5245 lines
146 KiB
C
5245 lines
146 KiB
C
/* GNU/Linux native-dependent code common to multiple platforms.
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Copyright (C) 2001-2015 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "inferior.h"
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#include "infrun.h"
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#include "target.h"
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#include "nat/linux-nat.h"
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#include "nat/linux-waitpid.h"
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#include "gdb_wait.h"
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#ifdef HAVE_TKILL_SYSCALL
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#include <unistd.h>
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#include <sys/syscall.h>
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#endif
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#include <sys/ptrace.h>
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#include "linux-nat.h"
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#include "nat/linux-ptrace.h"
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#include "nat/linux-procfs.h"
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#include "nat/linux-personality.h"
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#include "linux-fork.h"
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#include "gdbthread.h"
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#include "gdbcmd.h"
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#include "regcache.h"
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#include "regset.h"
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#include "inf-child.h"
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#include "inf-ptrace.h"
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#include "auxv.h"
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#include <sys/procfs.h> /* for elf_gregset etc. */
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#include "elf-bfd.h" /* for elfcore_write_* */
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#include "gregset.h" /* for gregset */
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#include "gdbcore.h" /* for get_exec_file */
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#include <ctype.h> /* for isdigit */
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#include <sys/stat.h> /* for struct stat */
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#include <fcntl.h> /* for O_RDONLY */
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#include "inf-loop.h"
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#include "event-loop.h"
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#include "event-top.h"
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#include <pwd.h>
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#include <sys/types.h>
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#include <dirent.h>
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#include "xml-support.h"
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#include <sys/vfs.h>
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#include "solib.h"
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#include "nat/linux-osdata.h"
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#include "linux-tdep.h"
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#include "symfile.h"
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#include "agent.h"
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#include "tracepoint.h"
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#include "buffer.h"
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#include "target-descriptions.h"
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#include "filestuff.h"
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#include "objfiles.h"
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#include "nat/linux-namespaces.h"
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#include "fileio.h"
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#ifndef SPUFS_MAGIC
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#define SPUFS_MAGIC 0x23c9b64e
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#endif
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/* This comment documents high-level logic of this file.
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Waiting for events in sync mode
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===============================
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When waiting for an event in a specific thread, we just use waitpid, passing
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the specific pid, and not passing WNOHANG.
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When waiting for an event in all threads, waitpid is not quite good. Prior to
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version 2.4, Linux can either wait for event in main thread, or in secondary
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threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
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miss an event. The solution is to use non-blocking waitpid, together with
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sigsuspend. First, we use non-blocking waitpid to get an event in the main
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process, if any. Second, we use non-blocking waitpid with the __WCLONED
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flag to check for events in cloned processes. If nothing is found, we use
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sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
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happened to a child process -- and SIGCHLD will be delivered both for events
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in main debugged process and in cloned processes. As soon as we know there's
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an event, we get back to calling nonblocking waitpid with and without
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__WCLONED.
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Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
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so that we don't miss a signal. If SIGCHLD arrives in between, when it's
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blocked, the signal becomes pending and sigsuspend immediately
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notices it and returns.
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Waiting for events in async mode
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================================
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In async mode, GDB should always be ready to handle both user input
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and target events, so neither blocking waitpid nor sigsuspend are
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viable options. Instead, we should asynchronously notify the GDB main
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event loop whenever there's an unprocessed event from the target. We
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detect asynchronous target events by handling SIGCHLD signals. To
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notify the event loop about target events, the self-pipe trick is used
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--- a pipe is registered as waitable event source in the event loop,
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the event loop select/poll's on the read end of this pipe (as well on
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other event sources, e.g., stdin), and the SIGCHLD handler writes a
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byte to this pipe. This is more portable than relying on
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pselect/ppoll, since on kernels that lack those syscalls, libc
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emulates them with select/poll+sigprocmask, and that is racy
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(a.k.a. plain broken).
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Obviously, if we fail to notify the event loop if there's a target
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event, it's bad. OTOH, if we notify the event loop when there's no
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event from the target, linux_nat_wait will detect that there's no real
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event to report, and return event of type TARGET_WAITKIND_IGNORE.
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This is mostly harmless, but it will waste time and is better avoided.
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The main design point is that every time GDB is outside linux-nat.c,
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we have a SIGCHLD handler installed that is called when something
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happens to the target and notifies the GDB event loop. Whenever GDB
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core decides to handle the event, and calls into linux-nat.c, we
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process things as in sync mode, except that the we never block in
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sigsuspend.
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While processing an event, we may end up momentarily blocked in
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waitpid calls. Those waitpid calls, while blocking, are guarantied to
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return quickly. E.g., in all-stop mode, before reporting to the core
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that an LWP hit a breakpoint, all LWPs are stopped by sending them
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SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
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Note that this is different from blocking indefinitely waiting for the
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next event --- here, we're already handling an event.
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Use of signals
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==============
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We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
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signal is not entirely significant; we just need for a signal to be delivered,
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so that we can intercept it. SIGSTOP's advantage is that it can not be
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blocked. A disadvantage is that it is not a real-time signal, so it can only
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be queued once; we do not keep track of other sources of SIGSTOP.
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Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
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use them, because they have special behavior when the signal is generated -
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not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
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kills the entire thread group.
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A delivered SIGSTOP would stop the entire thread group, not just the thread we
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tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
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cancel it (by PTRACE_CONT without passing SIGSTOP).
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We could use a real-time signal instead. This would solve those problems; we
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could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
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But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
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generates it, and there are races with trying to find a signal that is not
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blocked. */
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#ifndef O_LARGEFILE
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#define O_LARGEFILE 0
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#endif
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/* Does the current host support PTRACE_GETREGSET? */
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enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN;
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/* The single-threaded native GNU/Linux target_ops. We save a pointer for
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the use of the multi-threaded target. */
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static struct target_ops *linux_ops;
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static struct target_ops linux_ops_saved;
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/* The method to call, if any, when a new thread is attached. */
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static void (*linux_nat_new_thread) (struct lwp_info *);
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/* The method to call, if any, when a new fork is attached. */
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static linux_nat_new_fork_ftype *linux_nat_new_fork;
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/* The method to call, if any, when a process is no longer
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attached. */
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static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
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/* Hook to call prior to resuming a thread. */
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static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
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/* The method to call, if any, when the siginfo object needs to be
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converted between the layout returned by ptrace, and the layout in
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the architecture of the inferior. */
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static int (*linux_nat_siginfo_fixup) (siginfo_t *,
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gdb_byte *,
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int);
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/* The saved to_xfer_partial method, inherited from inf-ptrace.c.
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Called by our to_xfer_partial. */
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static target_xfer_partial_ftype *super_xfer_partial;
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/* The saved to_close method, inherited from inf-ptrace.c.
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Called by our to_close. */
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static void (*super_close) (struct target_ops *);
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static unsigned int debug_linux_nat;
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static void
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show_debug_linux_nat (struct ui_file *file, int from_tty,
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struct cmd_list_element *c, const char *value)
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{
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fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
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value);
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}
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struct simple_pid_list
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{
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int pid;
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int status;
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struct simple_pid_list *next;
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};
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struct simple_pid_list *stopped_pids;
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/* Async mode support. */
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/* The read/write ends of the pipe registered as waitable file in the
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event loop. */
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static int linux_nat_event_pipe[2] = { -1, -1 };
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/* True if we're currently in async mode. */
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#define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
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/* Flush the event pipe. */
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static void
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async_file_flush (void)
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{
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int ret;
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char buf;
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do
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{
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ret = read (linux_nat_event_pipe[0], &buf, 1);
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}
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while (ret >= 0 || (ret == -1 && errno == EINTR));
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}
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/* Put something (anything, doesn't matter what, or how much) in event
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pipe, so that the select/poll in the event-loop realizes we have
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something to process. */
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static void
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async_file_mark (void)
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{
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int ret;
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/* It doesn't really matter what the pipe contains, as long we end
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up with something in it. Might as well flush the previous
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left-overs. */
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async_file_flush ();
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do
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{
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ret = write (linux_nat_event_pipe[1], "+", 1);
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}
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while (ret == -1 && errno == EINTR);
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/* Ignore EAGAIN. If the pipe is full, the event loop will already
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be awakened anyway. */
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}
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static int kill_lwp (int lwpid, int signo);
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static int stop_callback (struct lwp_info *lp, void *data);
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static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
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static void block_child_signals (sigset_t *prev_mask);
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static void restore_child_signals_mask (sigset_t *prev_mask);
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struct lwp_info;
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static struct lwp_info *add_lwp (ptid_t ptid);
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static void purge_lwp_list (int pid);
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static void delete_lwp (ptid_t ptid);
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static struct lwp_info *find_lwp_pid (ptid_t ptid);
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static int lwp_status_pending_p (struct lwp_info *lp);
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static int check_stopped_by_breakpoint (struct lwp_info *lp);
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static int sigtrap_is_event (int status);
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static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
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/* LWP accessors. */
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/* See nat/linux-nat.h. */
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ptid_t
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ptid_of_lwp (struct lwp_info *lwp)
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{
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return lwp->ptid;
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}
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/* See nat/linux-nat.h. */
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void
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lwp_set_arch_private_info (struct lwp_info *lwp,
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struct arch_lwp_info *info)
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{
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lwp->arch_private = info;
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}
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/* See nat/linux-nat.h. */
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struct arch_lwp_info *
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lwp_arch_private_info (struct lwp_info *lwp)
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{
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return lwp->arch_private;
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}
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/* See nat/linux-nat.h. */
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int
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lwp_is_stopped (struct lwp_info *lwp)
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{
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return lwp->stopped;
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}
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/* See nat/linux-nat.h. */
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enum target_stop_reason
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lwp_stop_reason (struct lwp_info *lwp)
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{
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return lwp->stop_reason;
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}
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/* Trivial list manipulation functions to keep track of a list of
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new stopped processes. */
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static void
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add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
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{
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struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
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new_pid->pid = pid;
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new_pid->status = status;
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new_pid->next = *listp;
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*listp = new_pid;
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}
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static int
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in_pid_list_p (struct simple_pid_list *list, int pid)
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{
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struct simple_pid_list *p;
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for (p = list; p != NULL; p = p->next)
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if (p->pid == pid)
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return 1;
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return 0;
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}
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static int
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pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
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{
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struct simple_pid_list **p;
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for (p = listp; *p != NULL; p = &(*p)->next)
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if ((*p)->pid == pid)
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{
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struct simple_pid_list *next = (*p)->next;
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*statusp = (*p)->status;
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xfree (*p);
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*p = next;
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return 1;
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}
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return 0;
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}
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/* Return the ptrace options that we want to try to enable. */
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static int
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linux_nat_ptrace_options (int attached)
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{
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int options = 0;
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if (!attached)
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options |= PTRACE_O_EXITKILL;
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options |= (PTRACE_O_TRACESYSGOOD
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| PTRACE_O_TRACEVFORKDONE
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| PTRACE_O_TRACEVFORK
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| PTRACE_O_TRACEFORK
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| PTRACE_O_TRACEEXEC);
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return options;
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}
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/* Initialize ptrace warnings and check for supported ptrace
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features given PID.
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ATTACHED should be nonzero iff we attached to the inferior. */
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static void
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linux_init_ptrace (pid_t pid, int attached)
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{
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int options = linux_nat_ptrace_options (attached);
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linux_enable_event_reporting (pid, options);
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linux_ptrace_init_warnings ();
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}
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static void
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linux_child_post_attach (struct target_ops *self, int pid)
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{
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linux_init_ptrace (pid, 1);
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}
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||
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||
static void
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||
linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
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||
{
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linux_init_ptrace (ptid_get_pid (ptid), 0);
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||
}
|
||
|
||
/* Return the number of known LWPs in the tgid given by PID. */
|
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||
static int
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num_lwps (int pid)
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{
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int count = 0;
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struct lwp_info *lp;
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for (lp = lwp_list; lp; lp = lp->next)
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if (ptid_get_pid (lp->ptid) == pid)
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count++;
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return count;
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||
}
|
||
|
||
/* Call delete_lwp with prototype compatible for make_cleanup. */
|
||
|
||
static void
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||
delete_lwp_cleanup (void *lp_voidp)
|
||
{
|
||
struct lwp_info *lp = lp_voidp;
|
||
|
||
delete_lwp (lp->ptid);
|
||
}
|
||
|
||
/* Target hook for follow_fork. On entry inferior_ptid must be the
|
||
ptid of the followed inferior. At return, inferior_ptid will be
|
||
unchanged. */
|
||
|
||
static int
|
||
linux_child_follow_fork (struct target_ops *ops, int follow_child,
|
||
int detach_fork)
|
||
{
|
||
if (!follow_child)
|
||
{
|
||
struct lwp_info *child_lp = NULL;
|
||
int status = W_STOPCODE (0);
|
||
struct cleanup *old_chain;
|
||
int has_vforked;
|
||
ptid_t parent_ptid, child_ptid;
|
||
int parent_pid, child_pid;
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has_vforked = (inferior_thread ()->pending_follow.kind
|
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== TARGET_WAITKIND_VFORKED);
|
||
parent_ptid = inferior_ptid;
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child_ptid = inferior_thread ()->pending_follow.value.related_pid;
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parent_pid = ptid_get_lwp (parent_ptid);
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||
child_pid = ptid_get_lwp (child_ptid);
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||
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||
/* We're already attached to the parent, by default. */
|
||
old_chain = save_inferior_ptid ();
|
||
inferior_ptid = child_ptid;
|
||
child_lp = add_lwp (inferior_ptid);
|
||
child_lp->stopped = 1;
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||
child_lp->last_resume_kind = resume_stop;
|
||
|
||
/* Detach new forked process? */
|
||
if (detach_fork)
|
||
{
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||
make_cleanup (delete_lwp_cleanup, child_lp);
|
||
|
||
if (linux_nat_prepare_to_resume != NULL)
|
||
linux_nat_prepare_to_resume (child_lp);
|
||
|
||
/* When debugging an inferior in an architecture that supports
|
||
hardware single stepping on a kernel without commit
|
||
6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
|
||
process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
|
||
set if the parent process had them set.
|
||
To work around this, single step the child process
|
||
once before detaching to clear the flags. */
|
||
|
||
if (!gdbarch_software_single_step_p (target_thread_architecture
|
||
(child_lp->ptid)))
|
||
{
|
||
linux_disable_event_reporting (child_pid);
|
||
if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
|
||
perror_with_name (_("Couldn't do single step"));
|
||
if (my_waitpid (child_pid, &status, 0) < 0)
|
||
perror_with_name (_("Couldn't wait vfork process"));
|
||
}
|
||
|
||
if (WIFSTOPPED (status))
|
||
{
|
||
int signo;
|
||
|
||
signo = WSTOPSIG (status);
|
||
if (signo != 0
|
||
&& !signal_pass_state (gdb_signal_from_host (signo)))
|
||
signo = 0;
|
||
ptrace (PTRACE_DETACH, child_pid, 0, signo);
|
||
}
|
||
|
||
/* Resets value of inferior_ptid to parent ptid. */
|
||
do_cleanups (old_chain);
|
||
}
|
||
else
|
||
{
|
||
/* Let the thread_db layer learn about this new process. */
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
do_cleanups (old_chain);
|
||
|
||
if (has_vforked)
|
||
{
|
||
struct lwp_info *parent_lp;
|
||
|
||
parent_lp = find_lwp_pid (parent_ptid);
|
||
gdb_assert (linux_supports_tracefork () >= 0);
|
||
|
||
if (linux_supports_tracevforkdone ())
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LCFF: waiting for VFORK_DONE on %d\n",
|
||
parent_pid);
|
||
parent_lp->stopped = 1;
|
||
|
||
/* We'll handle the VFORK_DONE event like any other
|
||
event, in target_wait. */
|
||
}
|
||
else
|
||
{
|
||
/* We can't insert breakpoints until the child has
|
||
finished with the shared memory region. We need to
|
||
wait until that happens. Ideal would be to just
|
||
call:
|
||
- ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
|
||
- waitpid (parent_pid, &status, __WALL);
|
||
However, most architectures can't handle a syscall
|
||
being traced on the way out if it wasn't traced on
|
||
the way in.
|
||
|
||
We might also think to loop, continuing the child
|
||
until it exits or gets a SIGTRAP. One problem is
|
||
that the child might call ptrace with PTRACE_TRACEME.
|
||
|
||
There's no simple and reliable way to figure out when
|
||
the vforked child will be done with its copy of the
|
||
shared memory. We could step it out of the syscall,
|
||
two instructions, let it go, and then single-step the
|
||
parent once. When we have hardware single-step, this
|
||
would work; with software single-step it could still
|
||
be made to work but we'd have to be able to insert
|
||
single-step breakpoints in the child, and we'd have
|
||
to insert -just- the single-step breakpoint in the
|
||
parent. Very awkward.
|
||
|
||
In the end, the best we can do is to make sure it
|
||
runs for a little while. Hopefully it will be out of
|
||
range of any breakpoints we reinsert. Usually this
|
||
is only the single-step breakpoint at vfork's return
|
||
point. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LCFF: no VFORK_DONE "
|
||
"support, sleeping a bit\n");
|
||
|
||
usleep (10000);
|
||
|
||
/* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
|
||
and leave it pending. The next linux_nat_resume call
|
||
will notice a pending event, and bypasses actually
|
||
resuming the inferior. */
|
||
parent_lp->status = 0;
|
||
parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
|
||
parent_lp->stopped = 1;
|
||
|
||
/* If we're in async mode, need to tell the event loop
|
||
there's something here to process. */
|
||
if (target_is_async_p ())
|
||
async_file_mark ();
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
struct lwp_info *child_lp;
|
||
|
||
child_lp = add_lwp (inferior_ptid);
|
||
child_lp->stopped = 1;
|
||
child_lp->last_resume_kind = resume_stop;
|
||
|
||
/* Let the thread_db layer learn about this new process. */
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
|
||
static int
|
||
linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
|
||
{
|
||
return !linux_supports_tracefork ();
|
||
}
|
||
|
||
static int
|
||
linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
|
||
{
|
||
return !linux_supports_tracefork ();
|
||
}
|
||
|
||
static int
|
||
linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
|
||
{
|
||
return !linux_supports_tracefork ();
|
||
}
|
||
|
||
static int
|
||
linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
linux_child_set_syscall_catchpoint (struct target_ops *self,
|
||
int pid, int needed, int any_count,
|
||
int table_size, int *table)
|
||
{
|
||
if (!linux_supports_tracesysgood ())
|
||
return 1;
|
||
|
||
/* On GNU/Linux, we ignore the arguments. It means that we only
|
||
enable the syscall catchpoints, but do not disable them.
|
||
|
||
Also, we do not use the `table' information because we do not
|
||
filter system calls here. We let GDB do the logic for us. */
|
||
return 0;
|
||
}
|
||
|
||
/* On GNU/Linux there are no real LWP's. The closest thing to LWP's
|
||
are processes sharing the same VM space. A multi-threaded process
|
||
is basically a group of such processes. However, such a grouping
|
||
is almost entirely a user-space issue; the kernel doesn't enforce
|
||
such a grouping at all (this might change in the future). In
|
||
general, we'll rely on the threads library (i.e. the GNU/Linux
|
||
Threads library) to provide such a grouping.
|
||
|
||
It is perfectly well possible to write a multi-threaded application
|
||
without the assistance of a threads library, by using the clone
|
||
system call directly. This module should be able to give some
|
||
rudimentary support for debugging such applications if developers
|
||
specify the CLONE_PTRACE flag in the clone system call, and are
|
||
using the Linux kernel 2.4 or above.
|
||
|
||
Note that there are some peculiarities in GNU/Linux that affect
|
||
this code:
|
||
|
||
- In general one should specify the __WCLONE flag to waitpid in
|
||
order to make it report events for any of the cloned processes
|
||
(and leave it out for the initial process). However, if a cloned
|
||
process has exited the exit status is only reported if the
|
||
__WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
|
||
we cannot use it since GDB must work on older systems too.
|
||
|
||
- When a traced, cloned process exits and is waited for by the
|
||
debugger, the kernel reassigns it to the original parent and
|
||
keeps it around as a "zombie". Somehow, the GNU/Linux Threads
|
||
library doesn't notice this, which leads to the "zombie problem":
|
||
When debugged a multi-threaded process that spawns a lot of
|
||
threads will run out of processes, even if the threads exit,
|
||
because the "zombies" stay around. */
|
||
|
||
/* List of known LWPs. */
|
||
struct lwp_info *lwp_list;
|
||
|
||
|
||
/* Original signal mask. */
|
||
static sigset_t normal_mask;
|
||
|
||
/* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
|
||
_initialize_linux_nat. */
|
||
static sigset_t suspend_mask;
|
||
|
||
/* Signals to block to make that sigsuspend work. */
|
||
static sigset_t blocked_mask;
|
||
|
||
/* SIGCHLD action. */
|
||
struct sigaction sigchld_action;
|
||
|
||
/* Block child signals (SIGCHLD and linux threads signals), and store
|
||
the previous mask in PREV_MASK. */
|
||
|
||
static void
|
||
block_child_signals (sigset_t *prev_mask)
|
||
{
|
||
/* Make sure SIGCHLD is blocked. */
|
||
if (!sigismember (&blocked_mask, SIGCHLD))
|
||
sigaddset (&blocked_mask, SIGCHLD);
|
||
|
||
sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
|
||
}
|
||
|
||
/* Restore child signals mask, previously returned by
|
||
block_child_signals. */
|
||
|
||
static void
|
||
restore_child_signals_mask (sigset_t *prev_mask)
|
||
{
|
||
sigprocmask (SIG_SETMASK, prev_mask, NULL);
|
||
}
|
||
|
||
/* Mask of signals to pass directly to the inferior. */
|
||
static sigset_t pass_mask;
|
||
|
||
/* Update signals to pass to the inferior. */
|
||
static void
|
||
linux_nat_pass_signals (struct target_ops *self,
|
||
int numsigs, unsigned char *pass_signals)
|
||
{
|
||
int signo;
|
||
|
||
sigemptyset (&pass_mask);
|
||
|
||
for (signo = 1; signo < NSIG; signo++)
|
||
{
|
||
int target_signo = gdb_signal_from_host (signo);
|
||
if (target_signo < numsigs && pass_signals[target_signo])
|
||
sigaddset (&pass_mask, signo);
|
||
}
|
||
}
|
||
|
||
|
||
|
||
/* Prototypes for local functions. */
|
||
static int stop_wait_callback (struct lwp_info *lp, void *data);
|
||
static int linux_thread_alive (ptid_t ptid);
|
||
static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
|
||
static int resume_stopped_resumed_lwps (struct lwp_info *lp, void *data);
|
||
|
||
|
||
|
||
/* Destroy and free LP. */
|
||
|
||
static void
|
||
lwp_free (struct lwp_info *lp)
|
||
{
|
||
xfree (lp->arch_private);
|
||
xfree (lp);
|
||
}
|
||
|
||
/* Remove all LWPs belong to PID from the lwp list. */
|
||
|
||
static void
|
||
purge_lwp_list (int pid)
|
||
{
|
||
struct lwp_info *lp, *lpprev, *lpnext;
|
||
|
||
lpprev = NULL;
|
||
|
||
for (lp = lwp_list; lp; lp = lpnext)
|
||
{
|
||
lpnext = lp->next;
|
||
|
||
if (ptid_get_pid (lp->ptid) == pid)
|
||
{
|
||
if (lp == lwp_list)
|
||
lwp_list = lp->next;
|
||
else
|
||
lpprev->next = lp->next;
|
||
|
||
lwp_free (lp);
|
||
}
|
||
else
|
||
lpprev = lp;
|
||
}
|
||
}
|
||
|
||
/* Add the LWP specified by PTID to the list. PTID is the first LWP
|
||
in the process. Return a pointer to the structure describing the
|
||
new LWP.
|
||
|
||
This differs from add_lwp in that we don't let the arch specific
|
||
bits know about this new thread. Current clients of this callback
|
||
take the opportunity to install watchpoints in the new thread, and
|
||
we shouldn't do that for the first thread. If we're spawning a
|
||
child ("run"), the thread executes the shell wrapper first, and we
|
||
shouldn't touch it until it execs the program we want to debug.
|
||
For "attach", it'd be okay to call the callback, but it's not
|
||
necessary, because watchpoints can't yet have been inserted into
|
||
the inferior. */
|
||
|
||
static struct lwp_info *
|
||
add_initial_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
gdb_assert (ptid_lwp_p (ptid));
|
||
|
||
lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
|
||
|
||
memset (lp, 0, sizeof (struct lwp_info));
|
||
|
||
lp->last_resume_kind = resume_continue;
|
||
lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
|
||
|
||
lp->ptid = ptid;
|
||
lp->core = -1;
|
||
|
||
lp->next = lwp_list;
|
||
lwp_list = lp;
|
||
|
||
return lp;
|
||
}
|
||
|
||
/* Add the LWP specified by PID to the list. Return a pointer to the
|
||
structure describing the new LWP. The LWP should already be
|
||
stopped. */
|
||
|
||
static struct lwp_info *
|
||
add_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
lp = add_initial_lwp (ptid);
|
||
|
||
/* Let the arch specific bits know about this new thread. Current
|
||
clients of this callback take the opportunity to install
|
||
watchpoints in the new thread. We don't do this for the first
|
||
thread though. See add_initial_lwp. */
|
||
if (linux_nat_new_thread != NULL)
|
||
linux_nat_new_thread (lp);
|
||
|
||
return lp;
|
||
}
|
||
|
||
/* Remove the LWP specified by PID from the list. */
|
||
|
||
static void
|
||
delete_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp, *lpprev;
|
||
|
||
lpprev = NULL;
|
||
|
||
for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
|
||
if (ptid_equal (lp->ptid, ptid))
|
||
break;
|
||
|
||
if (!lp)
|
||
return;
|
||
|
||
if (lpprev)
|
||
lpprev->next = lp->next;
|
||
else
|
||
lwp_list = lp->next;
|
||
|
||
lwp_free (lp);
|
||
}
|
||
|
||
/* Return a pointer to the structure describing the LWP corresponding
|
||
to PID. If no corresponding LWP could be found, return NULL. */
|
||
|
||
static struct lwp_info *
|
||
find_lwp_pid (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
int lwp;
|
||
|
||
if (ptid_lwp_p (ptid))
|
||
lwp = ptid_get_lwp (ptid);
|
||
else
|
||
lwp = ptid_get_pid (ptid);
|
||
|
||
for (lp = lwp_list; lp; lp = lp->next)
|
||
if (lwp == ptid_get_lwp (lp->ptid))
|
||
return lp;
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
struct lwp_info *
|
||
iterate_over_lwps (ptid_t filter,
|
||
iterate_over_lwps_ftype callback,
|
||
void *data)
|
||
{
|
||
struct lwp_info *lp, *lpnext;
|
||
|
||
for (lp = lwp_list; lp; lp = lpnext)
|
||
{
|
||
lpnext = lp->next;
|
||
|
||
if (ptid_match (lp->ptid, filter))
|
||
{
|
||
if ((*callback) (lp, data) != 0)
|
||
return lp;
|
||
}
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Update our internal state when changing from one checkpoint to
|
||
another indicated by NEW_PTID. We can only switch single-threaded
|
||
applications, so we only create one new LWP, and the previous list
|
||
is discarded. */
|
||
|
||
void
|
||
linux_nat_switch_fork (ptid_t new_ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
purge_lwp_list (ptid_get_pid (inferior_ptid));
|
||
|
||
lp = add_lwp (new_ptid);
|
||
lp->stopped = 1;
|
||
|
||
/* This changes the thread's ptid while preserving the gdb thread
|
||
num. Also changes the inferior pid, while preserving the
|
||
inferior num. */
|
||
thread_change_ptid (inferior_ptid, new_ptid);
|
||
|
||
/* We've just told GDB core that the thread changed target id, but,
|
||
in fact, it really is a different thread, with different register
|
||
contents. */
|
||
registers_changed ();
|
||
}
|
||
|
||
/* Handle the exit of a single thread LP. */
|
||
|
||
static void
|
||
exit_lwp (struct lwp_info *lp)
|
||
{
|
||
struct thread_info *th = find_thread_ptid (lp->ptid);
|
||
|
||
if (th)
|
||
{
|
||
if (print_thread_events)
|
||
printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
|
||
|
||
delete_thread (lp->ptid);
|
||
}
|
||
|
||
delete_lwp (lp->ptid);
|
||
}
|
||
|
||
/* Wait for the LWP specified by LP, which we have just attached to.
|
||
Returns a wait status for that LWP, to cache. */
|
||
|
||
static int
|
||
linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
|
||
int *signalled)
|
||
{
|
||
pid_t new_pid, pid = ptid_get_lwp (ptid);
|
||
int status;
|
||
|
||
if (linux_proc_pid_is_stopped (pid))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNPAW: Attaching to a stopped process\n");
|
||
|
||
/* The process is definitely stopped. It is in a job control
|
||
stop, unless the kernel predates the TASK_STOPPED /
|
||
TASK_TRACED distinction, in which case it might be in a
|
||
ptrace stop. Make sure it is in a ptrace stop; from there we
|
||
can kill it, signal it, et cetera.
|
||
|
||
First make sure there is a pending SIGSTOP. Since we are
|
||
already attached, the process can not transition from stopped
|
||
to running without a PTRACE_CONT; so we know this signal will
|
||
go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
|
||
probably already in the queue (unless this kernel is old
|
||
enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
|
||
is not an RT signal, it can only be queued once. */
|
||
kill_lwp (pid, SIGSTOP);
|
||
|
||
/* Finally, resume the stopped process. This will deliver the SIGSTOP
|
||
(or a higher priority signal, just like normal PTRACE_ATTACH). */
|
||
ptrace (PTRACE_CONT, pid, 0, 0);
|
||
}
|
||
|
||
/* Make sure the initial process is stopped. The user-level threads
|
||
layer might want to poke around in the inferior, and that won't
|
||
work if things haven't stabilized yet. */
|
||
new_pid = my_waitpid (pid, &status, 0);
|
||
if (new_pid == -1 && errno == ECHILD)
|
||
{
|
||
if (first)
|
||
warning (_("%s is a cloned process"), target_pid_to_str (ptid));
|
||
|
||
/* Try again with __WCLONE to check cloned processes. */
|
||
new_pid = my_waitpid (pid, &status, __WCLONE);
|
||
*cloned = 1;
|
||
}
|
||
|
||
gdb_assert (pid == new_pid);
|
||
|
||
if (!WIFSTOPPED (status))
|
||
{
|
||
/* The pid we tried to attach has apparently just exited. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
|
||
pid, status_to_str (status));
|
||
return status;
|
||
}
|
||
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
*signalled = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNPAW: Received %s after attaching\n",
|
||
status_to_str (status));
|
||
}
|
||
|
||
return status;
|
||
}
|
||
|
||
/* Attach to the LWP specified by PID. Return 0 if successful, -1 if
|
||
the new LWP could not be attached, or 1 if we're already auto
|
||
attached to this thread, but haven't processed the
|
||
PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
|
||
its existance, without considering it an error. */
|
||
|
||
int
|
||
lin_lwp_attach_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
int lwpid;
|
||
|
||
gdb_assert (ptid_lwp_p (ptid));
|
||
|
||
lp = find_lwp_pid (ptid);
|
||
lwpid = ptid_get_lwp (ptid);
|
||
|
||
/* We assume that we're already attached to any LWP that is already
|
||
in our list of LWPs. If we're not seeing exit events from threads
|
||
and we've had PID wraparound since we last tried to stop all threads,
|
||
this assumption might be wrong; fortunately, this is very unlikely
|
||
to happen. */
|
||
if (lp == NULL)
|
||
{
|
||
int status, cloned = 0, signalled = 0;
|
||
|
||
if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
|
||
{
|
||
if (linux_supports_tracefork ())
|
||
{
|
||
/* If we haven't stopped all threads when we get here,
|
||
we may have seen a thread listed in thread_db's list,
|
||
but not processed the PTRACE_EVENT_CLONE yet. If
|
||
that's the case, ignore this new thread, and let
|
||
normal event handling discover it later. */
|
||
if (in_pid_list_p (stopped_pids, lwpid))
|
||
{
|
||
/* We've already seen this thread stop, but we
|
||
haven't seen the PTRACE_EVENT_CLONE extended
|
||
event yet. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLAL: attach failed, but already seen "
|
||
"this thread %s stop\n",
|
||
target_pid_to_str (ptid));
|
||
return 1;
|
||
}
|
||
else
|
||
{
|
||
int new_pid;
|
||
int status;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLAL: attach failed, and haven't seen "
|
||
"this thread %s stop yet\n",
|
||
target_pid_to_str (ptid));
|
||
|
||
/* We may or may not be attached to the LWP already.
|
||
Try waitpid on it. If that errors, we're not
|
||
attached to the LWP yet. Otherwise, we're
|
||
already attached. */
|
||
gdb_assert (lwpid > 0);
|
||
new_pid = my_waitpid (lwpid, &status, WNOHANG);
|
||
if (new_pid == -1 && errno == ECHILD)
|
||
new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
|
||
if (new_pid != -1)
|
||
{
|
||
if (new_pid == 0)
|
||
{
|
||
/* The child hasn't stopped for its initial
|
||
SIGSTOP stop yet. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLAL: child hasn't "
|
||
"stopped yet\n");
|
||
}
|
||
else if (WIFSTOPPED (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLAL: adding to stopped_pids\n");
|
||
add_to_pid_list (&stopped_pids, lwpid, status);
|
||
}
|
||
return 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If we fail to attach to the thread, issue a warning,
|
||
but continue. One way this can happen is if thread
|
||
creation is interrupted; as of Linux kernel 2.6.19, a
|
||
bug may place threads in the thread list and then fail
|
||
to create them. */
|
||
warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
|
||
safe_strerror (errno));
|
||
return -1;
|
||
}
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
|
||
target_pid_to_str (ptid));
|
||
|
||
status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
|
||
if (!WIFSTOPPED (status))
|
||
return 1;
|
||
|
||
lp = add_lwp (ptid);
|
||
lp->stopped = 1;
|
||
lp->last_resume_kind = resume_stop;
|
||
lp->cloned = cloned;
|
||
lp->signalled = signalled;
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
lp->resumed = 1;
|
||
lp->status = status;
|
||
}
|
||
|
||
target_post_attach (ptid_get_lwp (lp->ptid));
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLAL: waitpid %s received %s\n",
|
||
target_pid_to_str (ptid),
|
||
status_to_str (status));
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
linux_nat_create_inferior (struct target_ops *ops,
|
||
char *exec_file, char *allargs, char **env,
|
||
int from_tty)
|
||
{
|
||
struct cleanup *restore_personality
|
||
= maybe_disable_address_space_randomization (disable_randomization);
|
||
|
||
/* The fork_child mechanism is synchronous and calls target_wait, so
|
||
we have to mask the async mode. */
|
||
|
||
/* Make sure we report all signals during startup. */
|
||
linux_nat_pass_signals (ops, 0, NULL);
|
||
|
||
linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
|
||
|
||
do_cleanups (restore_personality);
|
||
}
|
||
|
||
/* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
|
||
already attached. Returns true if a new LWP is found, false
|
||
otherwise. */
|
||
|
||
static int
|
||
attach_proc_task_lwp_callback (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
/* Ignore LWPs we're already attached to. */
|
||
lp = find_lwp_pid (ptid);
|
||
if (lp == NULL)
|
||
{
|
||
int lwpid = ptid_get_lwp (ptid);
|
||
|
||
if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
|
||
{
|
||
int err = errno;
|
||
|
||
/* Be quiet if we simply raced with the thread exiting.
|
||
EPERM is returned if the thread's task still exists, and
|
||
is marked as exited or zombie, as well as other
|
||
conditions, so in that case, confirm the status in
|
||
/proc/PID/status. */
|
||
if (err == ESRCH
|
||
|| (err == EPERM && linux_proc_pid_is_gone (lwpid)))
|
||
{
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"Cannot attach to lwp %d: "
|
||
"thread is gone (%d: %s)\n",
|
||
lwpid, err, safe_strerror (err));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
warning (_("Cannot attach to lwp %d: %s"),
|
||
lwpid,
|
||
linux_ptrace_attach_fail_reason_string (ptid,
|
||
err));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"PTRACE_ATTACH %s, 0, 0 (OK)\n",
|
||
target_pid_to_str (ptid));
|
||
|
||
lp = add_lwp (ptid);
|
||
lp->cloned = 1;
|
||
|
||
/* The next time we wait for this LWP we'll see a SIGSTOP as
|
||
PTRACE_ATTACH brings it to a halt. */
|
||
lp->signalled = 1;
|
||
|
||
/* We need to wait for a stop before being able to make the
|
||
next ptrace call on this LWP. */
|
||
lp->must_set_ptrace_flags = 1;
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
|
||
{
|
||
struct lwp_info *lp;
|
||
int status;
|
||
ptid_t ptid;
|
||
|
||
/* Make sure we report all signals during attach. */
|
||
linux_nat_pass_signals (ops, 0, NULL);
|
||
|
||
TRY
|
||
{
|
||
linux_ops->to_attach (ops, args, from_tty);
|
||
}
|
||
CATCH (ex, RETURN_MASK_ERROR)
|
||
{
|
||
pid_t pid = parse_pid_to_attach (args);
|
||
struct buffer buffer;
|
||
char *message, *buffer_s;
|
||
|
||
message = xstrdup (ex.message);
|
||
make_cleanup (xfree, message);
|
||
|
||
buffer_init (&buffer);
|
||
linux_ptrace_attach_fail_reason (pid, &buffer);
|
||
|
||
buffer_grow_str0 (&buffer, "");
|
||
buffer_s = buffer_finish (&buffer);
|
||
make_cleanup (xfree, buffer_s);
|
||
|
||
if (*buffer_s != '\0')
|
||
throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
|
||
else
|
||
throw_error (ex.error, "%s", message);
|
||
}
|
||
END_CATCH
|
||
|
||
/* The ptrace base target adds the main thread with (pid,0,0)
|
||
format. Decorate it with lwp info. */
|
||
ptid = ptid_build (ptid_get_pid (inferior_ptid),
|
||
ptid_get_pid (inferior_ptid),
|
||
0);
|
||
thread_change_ptid (inferior_ptid, ptid);
|
||
|
||
/* Add the initial process as the first LWP to the list. */
|
||
lp = add_initial_lwp (ptid);
|
||
|
||
status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
|
||
&lp->signalled);
|
||
if (!WIFSTOPPED (status))
|
||
{
|
||
if (WIFEXITED (status))
|
||
{
|
||
int exit_code = WEXITSTATUS (status);
|
||
|
||
target_terminal_ours ();
|
||
target_mourn_inferior ();
|
||
if (exit_code == 0)
|
||
error (_("Unable to attach: program exited normally."));
|
||
else
|
||
error (_("Unable to attach: program exited with code %d."),
|
||
exit_code);
|
||
}
|
||
else if (WIFSIGNALED (status))
|
||
{
|
||
enum gdb_signal signo;
|
||
|
||
target_terminal_ours ();
|
||
target_mourn_inferior ();
|
||
|
||
signo = gdb_signal_from_host (WTERMSIG (status));
|
||
error (_("Unable to attach: program terminated with signal "
|
||
"%s, %s."),
|
||
gdb_signal_to_name (signo),
|
||
gdb_signal_to_string (signo));
|
||
}
|
||
|
||
internal_error (__FILE__, __LINE__,
|
||
_("unexpected status %d for PID %ld"),
|
||
status, (long) ptid_get_lwp (ptid));
|
||
}
|
||
|
||
lp->stopped = 1;
|
||
|
||
/* Save the wait status to report later. */
|
||
lp->resumed = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNA: waitpid %ld, saving status %s\n",
|
||
(long) ptid_get_pid (lp->ptid), status_to_str (status));
|
||
|
||
lp->status = status;
|
||
|
||
/* We must attach to every LWP. If /proc is mounted, use that to
|
||
find them now. The inferior may be using raw clone instead of
|
||
using pthreads. But even if it is using pthreads, thread_db
|
||
walks structures in the inferior's address space to find the list
|
||
of threads/LWPs, and those structures may well be corrupted.
|
||
Note that once thread_db is loaded, we'll still use it to list
|
||
threads and associate pthread info with each LWP. */
|
||
linux_proc_attach_tgid_threads (ptid_get_pid (lp->ptid),
|
||
attach_proc_task_lwp_callback);
|
||
|
||
if (target_can_async_p ())
|
||
target_async (1);
|
||
}
|
||
|
||
/* Get pending status of LP. */
|
||
static int
|
||
get_pending_status (struct lwp_info *lp, int *status)
|
||
{
|
||
enum gdb_signal signo = GDB_SIGNAL_0;
|
||
|
||
/* If we paused threads momentarily, we may have stored pending
|
||
events in lp->status or lp->waitstatus (see stop_wait_callback),
|
||
and GDB core hasn't seen any signal for those threads.
|
||
Otherwise, the last signal reported to the core is found in the
|
||
thread object's stop_signal.
|
||
|
||
There's a corner case that isn't handled here at present. Only
|
||
if the thread stopped with a TARGET_WAITKIND_STOPPED does
|
||
stop_signal make sense as a real signal to pass to the inferior.
|
||
Some catchpoint related events, like
|
||
TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
|
||
to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
|
||
those traps are debug API (ptrace in our case) related and
|
||
induced; the inferior wouldn't see them if it wasn't being
|
||
traced. Hence, we should never pass them to the inferior, even
|
||
when set to pass state. Since this corner case isn't handled by
|
||
infrun.c when proceeding with a signal, for consistency, neither
|
||
do we handle it here (or elsewhere in the file we check for
|
||
signal pass state). Normally SIGTRAP isn't set to pass state, so
|
||
this is really a corner case. */
|
||
|
||
if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
|
||
signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
|
||
else if (lp->status)
|
||
signo = gdb_signal_from_host (WSTOPSIG (lp->status));
|
||
else if (non_stop && !is_executing (lp->ptid))
|
||
{
|
||
struct thread_info *tp = find_thread_ptid (lp->ptid);
|
||
|
||
signo = tp->suspend.stop_signal;
|
||
}
|
||
else if (!non_stop)
|
||
{
|
||
struct target_waitstatus last;
|
||
ptid_t last_ptid;
|
||
|
||
get_last_target_status (&last_ptid, &last);
|
||
|
||
if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
|
||
{
|
||
struct thread_info *tp = find_thread_ptid (lp->ptid);
|
||
|
||
signo = tp->suspend.stop_signal;
|
||
}
|
||
}
|
||
|
||
*status = 0;
|
||
|
||
if (signo == GDB_SIGNAL_0)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"GPT: lwp %s has no pending signal\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
else if (!signal_pass_state (signo))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"GPT: lwp %s had signal %s, "
|
||
"but it is in no pass state\n",
|
||
target_pid_to_str (lp->ptid),
|
||
gdb_signal_to_string (signo));
|
||
}
|
||
else
|
||
{
|
||
*status = W_STOPCODE (gdb_signal_to_host (signo));
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"GPT: lwp %s has pending signal %s\n",
|
||
target_pid_to_str (lp->ptid),
|
||
gdb_signal_to_string (signo));
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
detach_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
|
||
|
||
if (debug_linux_nat && lp->status)
|
||
fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
|
||
strsignal (WSTOPSIG (lp->status)),
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
/* If there is a pending SIGSTOP, get rid of it. */
|
||
if (lp->signalled)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"DC: Sending SIGCONT to %s\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
|
||
lp->signalled = 0;
|
||
}
|
||
|
||
/* We don't actually detach from the LWP that has an id equal to the
|
||
overall process id just yet. */
|
||
if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
|
||
{
|
||
int status = 0;
|
||
|
||
/* Pass on any pending signal for this LWP. */
|
||
get_pending_status (lp, &status);
|
||
|
||
if (linux_nat_prepare_to_resume != NULL)
|
||
linux_nat_prepare_to_resume (lp);
|
||
errno = 0;
|
||
if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
|
||
WSTOPSIG (status)) < 0)
|
||
error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
|
||
safe_strerror (errno));
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"PTRACE_DETACH (%s, %s, 0) (OK)\n",
|
||
target_pid_to_str (lp->ptid),
|
||
strsignal (WSTOPSIG (status)));
|
||
|
||
delete_lwp (lp->ptid);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
|
||
{
|
||
int pid;
|
||
int status;
|
||
struct lwp_info *main_lwp;
|
||
|
||
pid = ptid_get_pid (inferior_ptid);
|
||
|
||
/* Don't unregister from the event loop, as there may be other
|
||
inferiors running. */
|
||
|
||
/* Stop all threads before detaching. ptrace requires that the
|
||
thread is stopped to sucessfully detach. */
|
||
iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
|
||
|
||
iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
|
||
|
||
/* Only the initial process should be left right now. */
|
||
gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
|
||
|
||
main_lwp = find_lwp_pid (pid_to_ptid (pid));
|
||
|
||
/* Pass on any pending signal for the last LWP. */
|
||
if ((args == NULL || *args == '\0')
|
||
&& get_pending_status (main_lwp, &status) != -1
|
||
&& WIFSTOPPED (status))
|
||
{
|
||
char *tem;
|
||
|
||
/* Put the signal number in ARGS so that inf_ptrace_detach will
|
||
pass it along with PTRACE_DETACH. */
|
||
tem = alloca (8);
|
||
xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
|
||
args = tem;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LND: Sending signal %s to %s\n",
|
||
args,
|
||
target_pid_to_str (main_lwp->ptid));
|
||
}
|
||
|
||
if (linux_nat_prepare_to_resume != NULL)
|
||
linux_nat_prepare_to_resume (main_lwp);
|
||
delete_lwp (main_lwp->ptid);
|
||
|
||
if (forks_exist_p ())
|
||
{
|
||
/* Multi-fork case. The current inferior_ptid is being detached
|
||
from, but there are other viable forks to debug. Detach from
|
||
the current fork, and context-switch to the first
|
||
available. */
|
||
linux_fork_detach (args, from_tty);
|
||
}
|
||
else
|
||
linux_ops->to_detach (ops, args, from_tty);
|
||
}
|
||
|
||
/* Resume execution of the inferior process. If STEP is nonzero,
|
||
single-step it. If SIGNAL is nonzero, give it that signal. */
|
||
|
||
static void
|
||
linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
|
||
enum gdb_signal signo)
|
||
{
|
||
lp->step = step;
|
||
|
||
/* stop_pc doubles as the PC the LWP had when it was last resumed.
|
||
We only presently need that if the LWP is stepped though (to
|
||
handle the case of stepping a breakpoint instruction). */
|
||
if (step)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
|
||
lp->stop_pc = regcache_read_pc (regcache);
|
||
}
|
||
else
|
||
lp->stop_pc = 0;
|
||
|
||
if (linux_nat_prepare_to_resume != NULL)
|
||
linux_nat_prepare_to_resume (lp);
|
||
linux_ops->to_resume (linux_ops, lp->ptid, step, signo);
|
||
|
||
/* Successfully resumed. Clear state that no longer makes sense,
|
||
and mark the LWP as running. Must not do this before resuming
|
||
otherwise if that fails other code will be confused. E.g., we'd
|
||
later try to stop the LWP and hang forever waiting for a stop
|
||
status. Note that we must not throw after this is cleared,
|
||
otherwise handle_zombie_lwp_error would get confused. */
|
||
lp->stopped = 0;
|
||
lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
|
||
registers_changed_ptid (lp->ptid);
|
||
}
|
||
|
||
/* Called when we try to resume a stopped LWP and that errors out. If
|
||
the LWP is no longer in ptrace-stopped state (meaning it's zombie,
|
||
or about to become), discard the error, clear any pending status
|
||
the LWP may have, and return true (we'll collect the exit status
|
||
soon enough). Otherwise, return false. */
|
||
|
||
static int
|
||
check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
|
||
{
|
||
/* If we get an error after resuming the LWP successfully, we'd
|
||
confuse !T state for the LWP being gone. */
|
||
gdb_assert (lp->stopped);
|
||
|
||
/* We can't just check whether the LWP is in 'Z (Zombie)' state,
|
||
because even if ptrace failed with ESRCH, the tracee may be "not
|
||
yet fully dead", but already refusing ptrace requests. In that
|
||
case the tracee has 'R (Running)' state for a little bit
|
||
(observed in Linux 3.18). See also the note on ESRCH in the
|
||
ptrace(2) man page. Instead, check whether the LWP has any state
|
||
other than ptrace-stopped. */
|
||
|
||
/* Don't assume anything if /proc/PID/status can't be read. */
|
||
if (linux_proc_pid_is_trace_stopped_nowarn (ptid_get_lwp (lp->ptid)) == 0)
|
||
{
|
||
lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
|
||
lp->status = 0;
|
||
lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
|
||
disappears while we try to resume it. */
|
||
|
||
static void
|
||
linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
|
||
{
|
||
TRY
|
||
{
|
||
linux_resume_one_lwp_throw (lp, step, signo);
|
||
}
|
||
CATCH (ex, RETURN_MASK_ERROR)
|
||
{
|
||
if (!check_ptrace_stopped_lwp_gone (lp))
|
||
throw_exception (ex);
|
||
}
|
||
END_CATCH
|
||
}
|
||
|
||
/* Resume LP. */
|
||
|
||
static void
|
||
resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
|
||
{
|
||
if (lp->stopped)
|
||
{
|
||
struct inferior *inf = find_inferior_ptid (lp->ptid);
|
||
|
||
if (inf->vfork_child != NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Not resuming %s (vfork parent)\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
else if (!lwp_status_pending_p (lp))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Resuming sibling %s, %s, %s\n",
|
||
target_pid_to_str (lp->ptid),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo))
|
||
: "0"),
|
||
step ? "step" : "resume");
|
||
|
||
linux_resume_one_lwp (lp, step, signo);
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Not resuming sibling %s (has pending)\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Not resuming sibling %s (not stopped)\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
}
|
||
|
||
/* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
|
||
Resume LWP with the last stop signal, if it is in pass state. */
|
||
|
||
static int
|
||
linux_nat_resume_callback (struct lwp_info *lp, void *except)
|
||
{
|
||
enum gdb_signal signo = GDB_SIGNAL_0;
|
||
|
||
if (lp == except)
|
||
return 0;
|
||
|
||
if (lp->stopped)
|
||
{
|
||
struct thread_info *thread;
|
||
|
||
thread = find_thread_ptid (lp->ptid);
|
||
if (thread != NULL)
|
||
{
|
||
signo = thread->suspend.stop_signal;
|
||
thread->suspend.stop_signal = GDB_SIGNAL_0;
|
||
}
|
||
}
|
||
|
||
resume_lwp (lp, 0, signo);
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
resume_clear_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
lp->resumed = 0;
|
||
lp->last_resume_kind = resume_stop;
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
resume_set_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
lp->resumed = 1;
|
||
lp->last_resume_kind = resume_continue;
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
linux_nat_resume (struct target_ops *ops,
|
||
ptid_t ptid, int step, enum gdb_signal signo)
|
||
{
|
||
struct lwp_info *lp;
|
||
int resume_many;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
|
||
step ? "step" : "resume",
|
||
target_pid_to_str (ptid),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo)) : "0"),
|
||
target_pid_to_str (inferior_ptid));
|
||
|
||
/* A specific PTID means `step only this process id'. */
|
||
resume_many = (ptid_equal (minus_one_ptid, ptid)
|
||
|| ptid_is_pid (ptid));
|
||
|
||
/* Mark the lwps we're resuming as resumed. */
|
||
iterate_over_lwps (ptid, resume_set_callback, NULL);
|
||
|
||
/* See if it's the current inferior that should be handled
|
||
specially. */
|
||
if (resume_many)
|
||
lp = find_lwp_pid (inferior_ptid);
|
||
else
|
||
lp = find_lwp_pid (ptid);
|
||
gdb_assert (lp != NULL);
|
||
|
||
/* Remember if we're stepping. */
|
||
lp->last_resume_kind = step ? resume_step : resume_continue;
|
||
|
||
/* If we have a pending wait status for this thread, there is no
|
||
point in resuming the process. But first make sure that
|
||
linux_nat_wait won't preemptively handle the event - we
|
||
should never take this short-circuit if we are going to
|
||
leave LP running, since we have skipped resuming all the
|
||
other threads. This bit of code needs to be synchronized
|
||
with linux_nat_wait. */
|
||
|
||
if (lp->status && WIFSTOPPED (lp->status))
|
||
{
|
||
if (!lp->step
|
||
&& WSTOPSIG (lp->status)
|
||
&& sigismember (&pass_mask, WSTOPSIG (lp->status)))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: Not short circuiting for ignored "
|
||
"status 0x%x\n", lp->status);
|
||
|
||
/* FIXME: What should we do if we are supposed to continue
|
||
this thread with a signal? */
|
||
gdb_assert (signo == GDB_SIGNAL_0);
|
||
signo = gdb_signal_from_host (WSTOPSIG (lp->status));
|
||
lp->status = 0;
|
||
}
|
||
}
|
||
|
||
if (lwp_status_pending_p (lp))
|
||
{
|
||
/* FIXME: What should we do if we are supposed to continue
|
||
this thread with a signal? */
|
||
gdb_assert (signo == GDB_SIGNAL_0);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: Short circuiting for status 0x%x\n",
|
||
lp->status);
|
||
|
||
if (target_can_async_p ())
|
||
{
|
||
target_async (1);
|
||
/* Tell the event loop we have something to process. */
|
||
async_file_mark ();
|
||
}
|
||
return;
|
||
}
|
||
|
||
if (resume_many)
|
||
iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: %s %s, %s (resume event thread)\n",
|
||
step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo)) : "0"));
|
||
|
||
linux_resume_one_lwp (lp, step, signo);
|
||
|
||
if (target_can_async_p ())
|
||
target_async (1);
|
||
}
|
||
|
||
/* Send a signal to an LWP. */
|
||
|
||
static int
|
||
kill_lwp (int lwpid, int signo)
|
||
{
|
||
/* Use tkill, if possible, in case we are using nptl threads. If tkill
|
||
fails, then we are not using nptl threads and we should be using kill. */
|
||
|
||
#ifdef HAVE_TKILL_SYSCALL
|
||
{
|
||
static int tkill_failed;
|
||
|
||
if (!tkill_failed)
|
||
{
|
||
int ret;
|
||
|
||
errno = 0;
|
||
ret = syscall (__NR_tkill, lwpid, signo);
|
||
if (errno != ENOSYS)
|
||
return ret;
|
||
tkill_failed = 1;
|
||
}
|
||
}
|
||
#endif
|
||
|
||
return kill (lwpid, signo);
|
||
}
|
||
|
||
/* Handle a GNU/Linux syscall trap wait response. If we see a syscall
|
||
event, check if the core is interested in it: if not, ignore the
|
||
event, and keep waiting; otherwise, we need to toggle the LWP's
|
||
syscall entry/exit status, since the ptrace event itself doesn't
|
||
indicate it, and report the trap to higher layers. */
|
||
|
||
static int
|
||
linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
|
||
{
|
||
struct target_waitstatus *ourstatus = &lp->waitstatus;
|
||
struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
|
||
int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
|
||
|
||
if (stopping)
|
||
{
|
||
/* If we're stopping threads, there's a SIGSTOP pending, which
|
||
makes it so that the LWP reports an immediate syscall return,
|
||
followed by the SIGSTOP. Skip seeing that "return" using
|
||
PTRACE_CONT directly, and let stop_wait_callback collect the
|
||
SIGSTOP. Later when the thread is resumed, a new syscall
|
||
entry event. If we didn't do this (and returned 0), we'd
|
||
leave a syscall entry pending, and our caller, by using
|
||
PTRACE_CONT to collect the SIGSTOP, skips the syscall return
|
||
itself. Later, when the user re-resumes this LWP, we'd see
|
||
another syscall entry event and we'd mistake it for a return.
|
||
|
||
If stop_wait_callback didn't force the SIGSTOP out of the LWP
|
||
(leaving immediately with LWP->signalled set, without issuing
|
||
a PTRACE_CONT), it would still be problematic to leave this
|
||
syscall enter pending, as later when the thread is resumed,
|
||
it would then see the same syscall exit mentioned above,
|
||
followed by the delayed SIGSTOP, while the syscall didn't
|
||
actually get to execute. It seems it would be even more
|
||
confusing to the user. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: ignoring syscall %d "
|
||
"for LWP %ld (stopping threads), "
|
||
"resuming with PTRACE_CONT for SIGSTOP\n",
|
||
syscall_number,
|
||
ptid_get_lwp (lp->ptid));
|
||
|
||
lp->syscall_state = TARGET_WAITKIND_IGNORE;
|
||
ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
|
||
lp->stopped = 0;
|
||
return 1;
|
||
}
|
||
|
||
if (catch_syscall_enabled ())
|
||
{
|
||
/* Always update the entry/return state, even if this particular
|
||
syscall isn't interesting to the core now. In async mode,
|
||
the user could install a new catchpoint for this syscall
|
||
between syscall enter/return, and we'll need to know to
|
||
report a syscall return if that happens. */
|
||
lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
|
||
? TARGET_WAITKIND_SYSCALL_RETURN
|
||
: TARGET_WAITKIND_SYSCALL_ENTRY);
|
||
|
||
if (catching_syscall_number (syscall_number))
|
||
{
|
||
/* Alright, an event to report. */
|
||
ourstatus->kind = lp->syscall_state;
|
||
ourstatus->value.syscall_number = syscall_number;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: stopping for %s of syscall %d"
|
||
" for LWP %ld\n",
|
||
lp->syscall_state
|
||
== TARGET_WAITKIND_SYSCALL_ENTRY
|
||
? "entry" : "return",
|
||
syscall_number,
|
||
ptid_get_lwp (lp->ptid));
|
||
return 0;
|
||
}
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: ignoring %s of syscall %d "
|
||
"for LWP %ld\n",
|
||
lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
|
||
? "entry" : "return",
|
||
syscall_number,
|
||
ptid_get_lwp (lp->ptid));
|
||
}
|
||
else
|
||
{
|
||
/* If we had been syscall tracing, and hence used PT_SYSCALL
|
||
before on this LWP, it could happen that the user removes all
|
||
syscall catchpoints before we get to process this event.
|
||
There are two noteworthy issues here:
|
||
|
||
- When stopped at a syscall entry event, resuming with
|
||
PT_STEP still resumes executing the syscall and reports a
|
||
syscall return.
|
||
|
||
- Only PT_SYSCALL catches syscall enters. If we last
|
||
single-stepped this thread, then this event can't be a
|
||
syscall enter. If we last single-stepped this thread, this
|
||
has to be a syscall exit.
|
||
|
||
The points above mean that the next resume, be it PT_STEP or
|
||
PT_CONTINUE, can not trigger a syscall trace event. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: caught syscall event "
|
||
"with no syscall catchpoints."
|
||
" %d for LWP %ld, ignoring\n",
|
||
syscall_number,
|
||
ptid_get_lwp (lp->ptid));
|
||
lp->syscall_state = TARGET_WAITKIND_IGNORE;
|
||
}
|
||
|
||
/* The core isn't interested in this event. For efficiency, avoid
|
||
stopping all threads only to have the core resume them all again.
|
||
Since we're not stopping threads, if we're still syscall tracing
|
||
and not stepping, we can't use PTRACE_CONT here, as we'd miss any
|
||
subsequent syscall. Simply resume using the inf-ptrace layer,
|
||
which knows when to use PT_SYSCALL or PT_CONTINUE. */
|
||
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
return 1;
|
||
}
|
||
|
||
/* Handle a GNU/Linux extended wait response. If we see a clone
|
||
event, we need to add the new LWP to our list (and not report the
|
||
trap to higher layers). This function returns non-zero if the
|
||
event should be ignored and we should wait again. If STOPPING is
|
||
true, the new LWP remains stopped, otherwise it is continued. */
|
||
|
||
static int
|
||
linux_handle_extended_wait (struct lwp_info *lp, int status,
|
||
int stopping)
|
||
{
|
||
int pid = ptid_get_lwp (lp->ptid);
|
||
struct target_waitstatus *ourstatus = &lp->waitstatus;
|
||
int event = linux_ptrace_get_extended_event (status);
|
||
|
||
if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
|
||
|| event == PTRACE_EVENT_CLONE)
|
||
{
|
||
unsigned long new_pid;
|
||
int ret;
|
||
|
||
ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
|
||
|
||
/* If we haven't already seen the new PID stop, wait for it now. */
|
||
if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
|
||
{
|
||
/* The new child has a pending SIGSTOP. We can't affect it until it
|
||
hits the SIGSTOP, but we're already attached. */
|
||
ret = my_waitpid (new_pid, &status,
|
||
(event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
|
||
if (ret == -1)
|
||
perror_with_name (_("waiting for new child"));
|
||
else if (ret != new_pid)
|
||
internal_error (__FILE__, __LINE__,
|
||
_("wait returned unexpected PID %d"), ret);
|
||
else if (!WIFSTOPPED (status))
|
||
internal_error (__FILE__, __LINE__,
|
||
_("wait returned unexpected status 0x%x"), status);
|
||
}
|
||
|
||
ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
|
||
|
||
if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
|
||
{
|
||
/* The arch-specific native code may need to know about new
|
||
forks even if those end up never mapped to an
|
||
inferior. */
|
||
if (linux_nat_new_fork != NULL)
|
||
linux_nat_new_fork (lp, new_pid);
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_FORK
|
||
&& linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
|
||
{
|
||
/* Handle checkpointing by linux-fork.c here as a special
|
||
case. We don't want the follow-fork-mode or 'catch fork'
|
||
to interfere with this. */
|
||
|
||
/* This won't actually modify the breakpoint list, but will
|
||
physically remove the breakpoints from the child. */
|
||
detach_breakpoints (ptid_build (new_pid, new_pid, 0));
|
||
|
||
/* Retain child fork in ptrace (stopped) state. */
|
||
if (!find_fork_pid (new_pid))
|
||
add_fork (new_pid);
|
||
|
||
/* Report as spurious, so that infrun doesn't want to follow
|
||
this fork. We're actually doing an infcall in
|
||
linux-fork.c. */
|
||
ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
|
||
|
||
/* Report the stop to the core. */
|
||
return 0;
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_FORK)
|
||
ourstatus->kind = TARGET_WAITKIND_FORKED;
|
||
else if (event == PTRACE_EVENT_VFORK)
|
||
ourstatus->kind = TARGET_WAITKIND_VFORKED;
|
||
else
|
||
{
|
||
struct lwp_info *new_lp;
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_IGNORE;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got clone event "
|
||
"from LWP %d, new child is LWP %ld\n",
|
||
pid, new_pid);
|
||
|
||
new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
|
||
new_lp->cloned = 1;
|
||
new_lp->stopped = 1;
|
||
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
/* This can happen if someone starts sending signals to
|
||
the new thread before it gets a chance to run, which
|
||
have a lower number than SIGSTOP (e.g. SIGUSR1).
|
||
This is an unlikely case, and harder to handle for
|
||
fork / vfork than for clone, so we do not try - but
|
||
we handle it for clone events here. We'll send
|
||
the other signal on to the thread below. */
|
||
|
||
new_lp->signalled = 1;
|
||
}
|
||
else
|
||
{
|
||
struct thread_info *tp;
|
||
|
||
/* When we stop for an event in some other thread, and
|
||
pull the thread list just as this thread has cloned,
|
||
we'll have seen the new thread in the thread_db list
|
||
before handling the CLONE event (glibc's
|
||
pthread_create adds the new thread to the thread list
|
||
before clone'ing, and has the kernel fill in the
|
||
thread's tid on the clone call with
|
||
CLONE_PARENT_SETTID). If that happened, and the core
|
||
had requested the new thread to stop, we'll have
|
||
killed it with SIGSTOP. But since SIGSTOP is not an
|
||
RT signal, it can only be queued once. We need to be
|
||
careful to not resume the LWP if we wanted it to
|
||
stop. In that case, we'll leave the SIGSTOP pending.
|
||
It will later be reported as GDB_SIGNAL_0. */
|
||
tp = find_thread_ptid (new_lp->ptid);
|
||
if (tp != NULL && tp->stop_requested)
|
||
new_lp->last_resume_kind = resume_stop;
|
||
else
|
||
status = 0;
|
||
}
|
||
|
||
/* If the thread_db layer is active, let it record the user
|
||
level thread id and status, and add the thread to GDB's
|
||
list. */
|
||
if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
|
||
{
|
||
/* The process is not using thread_db. Add the LWP to
|
||
GDB's list. */
|
||
target_post_attach (ptid_get_lwp (new_lp->ptid));
|
||
add_thread (new_lp->ptid);
|
||
}
|
||
|
||
/* Even if we're stopping the thread for some reason
|
||
internal to this module, from the user/frontend's
|
||
perspective, this new thread is running. */
|
||
set_running (new_lp->ptid, 1);
|
||
if (!stopping)
|
||
{
|
||
set_executing (new_lp->ptid, 1);
|
||
/* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
|
||
resume_stop. */
|
||
new_lp->last_resume_kind = resume_continue;
|
||
}
|
||
|
||
if (status != 0)
|
||
{
|
||
/* We created NEW_LP so it cannot yet contain STATUS. */
|
||
gdb_assert (new_lp->status == 0);
|
||
|
||
/* Save the wait status to report later. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: waitpid of new LWP %ld, "
|
||
"saving status %s\n",
|
||
(long) ptid_get_lwp (new_lp->ptid),
|
||
status_to_str (status));
|
||
new_lp->status = status;
|
||
}
|
||
|
||
new_lp->resumed = !stopping;
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_EXEC)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got exec event from LWP %ld\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_EXECD;
|
||
ourstatus->value.execd_pathname
|
||
= xstrdup (linux_child_pid_to_exec_file (NULL, pid));
|
||
|
||
/* The thread that execed must have been resumed, but, when a
|
||
thread execs, it changes its tid to the tgid, and the old
|
||
tgid thread might have not been resumed. */
|
||
lp->resumed = 1;
|
||
return 0;
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_VFORK_DONE)
|
||
{
|
||
if (current_inferior ()->waiting_for_vfork_done)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got expected PTRACE_EVENT_"
|
||
"VFORK_DONE from LWP %ld: stopping\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
|
||
return 0;
|
||
}
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got PTRACE_EVENT_VFORK_DONE "
|
||
"from LWP %ld: ignoring\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
return 1;
|
||
}
|
||
|
||
internal_error (__FILE__, __LINE__,
|
||
_("unknown ptrace event %d"), event);
|
||
}
|
||
|
||
/* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
|
||
exited. */
|
||
|
||
static int
|
||
wait_lwp (struct lwp_info *lp)
|
||
{
|
||
pid_t pid;
|
||
int status = 0;
|
||
int thread_dead = 0;
|
||
sigset_t prev_mask;
|
||
|
||
gdb_assert (!lp->stopped);
|
||
gdb_assert (lp->status == 0);
|
||
|
||
/* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
|
||
block_child_signals (&prev_mask);
|
||
|
||
for (;;)
|
||
{
|
||
/* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
|
||
was right and we should just call sigsuspend. */
|
||
|
||
pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
|
||
if (pid == -1 && errno == ECHILD)
|
||
pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
|
||
if (pid == -1 && errno == ECHILD)
|
||
{
|
||
/* The thread has previously exited. We need to delete it
|
||
now because, for some vendor 2.4 kernels with NPTL
|
||
support backported, there won't be an exit event unless
|
||
it is the main thread. 2.6 kernels will report an exit
|
||
event for each thread that exits, as expected. */
|
||
thread_dead = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
if (pid != 0)
|
||
break;
|
||
|
||
/* Bugs 10970, 12702.
|
||
Thread group leader may have exited in which case we'll lock up in
|
||
waitpid if there are other threads, even if they are all zombies too.
|
||
Basically, we're not supposed to use waitpid this way.
|
||
__WCLONE is not applicable for the leader so we can't use that.
|
||
LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
|
||
process; it gets ESRCH both for the zombie and for running processes.
|
||
|
||
As a workaround, check if we're waiting for the thread group leader and
|
||
if it's a zombie, and avoid calling waitpid if it is.
|
||
|
||
This is racy, what if the tgl becomes a zombie right after we check?
|
||
Therefore always use WNOHANG with sigsuspend - it is equivalent to
|
||
waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
|
||
|
||
if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
|
||
&& linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
|
||
{
|
||
thread_dead = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"WL: Thread group leader %s vanished.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
break;
|
||
}
|
||
|
||
/* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
|
||
get invoked despite our caller had them intentionally blocked by
|
||
block_child_signals. This is sensitive only to the loop of
|
||
linux_nat_wait_1 and there if we get called my_waitpid gets called
|
||
again before it gets to sigsuspend so we can safely let the handlers
|
||
get executed here. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
|
||
sigsuspend (&suspend_mask);
|
||
}
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
|
||
if (!thread_dead)
|
||
{
|
||
gdb_assert (pid == ptid_get_lwp (lp->ptid));
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"WL: waitpid %s received %s\n",
|
||
target_pid_to_str (lp->ptid),
|
||
status_to_str (status));
|
||
}
|
||
|
||
/* Check if the thread has exited. */
|
||
if (WIFEXITED (status) || WIFSIGNALED (status))
|
||
{
|
||
thread_dead = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
}
|
||
|
||
if (thread_dead)
|
||
{
|
||
exit_lwp (lp);
|
||
return 0;
|
||
}
|
||
|
||
gdb_assert (WIFSTOPPED (status));
|
||
lp->stopped = 1;
|
||
|
||
if (lp->must_set_ptrace_flags)
|
||
{
|
||
struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
|
||
int options = linux_nat_ptrace_options (inf->attach_flag);
|
||
|
||
linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
|
||
lp->must_set_ptrace_flags = 0;
|
||
}
|
||
|
||
/* Handle GNU/Linux's syscall SIGTRAPs. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
|
||
{
|
||
/* No longer need the sysgood bit. The ptrace event ends up
|
||
recorded in lp->waitstatus if we care for it. We can carry
|
||
on handling the event like a regular SIGTRAP from here
|
||
on. */
|
||
status = W_STOPCODE (SIGTRAP);
|
||
if (linux_handle_syscall_trap (lp, 1))
|
||
return wait_lwp (lp);
|
||
}
|
||
|
||
/* Handle GNU/Linux's extended waitstatus for trace events. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
|
||
&& linux_is_extended_waitstatus (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"WL: Handling extended status 0x%06x\n",
|
||
status);
|
||
linux_handle_extended_wait (lp, status, 1);
|
||
return 0;
|
||
}
|
||
|
||
return status;
|
||
}
|
||
|
||
/* Send a SIGSTOP to LP. */
|
||
|
||
static int
|
||
stop_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
if (!lp->stopped && !lp->signalled)
|
||
{
|
||
int ret;
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: kill %s **<SIGSTOP>**\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
errno = 0;
|
||
ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: lwp kill %d %s\n",
|
||
ret,
|
||
errno ? safe_strerror (errno) : "ERRNO-OK");
|
||
}
|
||
|
||
lp->signalled = 1;
|
||
gdb_assert (lp->status == 0);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Request a stop on LWP. */
|
||
|
||
void
|
||
linux_stop_lwp (struct lwp_info *lwp)
|
||
{
|
||
stop_callback (lwp, NULL);
|
||
}
|
||
|
||
/* See linux-nat.h */
|
||
|
||
void
|
||
linux_stop_and_wait_all_lwps (void)
|
||
{
|
||
/* Stop all LWP's ... */
|
||
iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
|
||
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
|
||
}
|
||
|
||
/* See linux-nat.h */
|
||
|
||
void
|
||
linux_unstop_all_lwps (void)
|
||
{
|
||
iterate_over_lwps (minus_one_ptid,
|
||
resume_stopped_resumed_lwps, &minus_one_ptid);
|
||
}
|
||
|
||
/* Return non-zero if LWP PID has a pending SIGINT. */
|
||
|
||
static int
|
||
linux_nat_has_pending_sigint (int pid)
|
||
{
|
||
sigset_t pending, blocked, ignored;
|
||
|
||
linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
|
||
|
||
if (sigismember (&pending, SIGINT)
|
||
&& !sigismember (&ignored, SIGINT))
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Set a flag in LP indicating that we should ignore its next SIGINT. */
|
||
|
||
static int
|
||
set_ignore_sigint (struct lwp_info *lp, void *data)
|
||
{
|
||
/* If a thread has a pending SIGINT, consume it; otherwise, set a
|
||
flag to consume the next one. */
|
||
if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
|
||
&& WSTOPSIG (lp->status) == SIGINT)
|
||
lp->status = 0;
|
||
else
|
||
lp->ignore_sigint = 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
|
||
This function is called after we know the LWP has stopped; if the LWP
|
||
stopped before the expected SIGINT was delivered, then it will never have
|
||
arrived. Also, if the signal was delivered to a shared queue and consumed
|
||
by a different thread, it will never be delivered to this LWP. */
|
||
|
||
static void
|
||
maybe_clear_ignore_sigint (struct lwp_info *lp)
|
||
{
|
||
if (!lp->ignore_sigint)
|
||
return;
|
||
|
||
if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"MCIS: Clearing bogus flag for %s\n",
|
||
target_pid_to_str (lp->ptid));
|
||
lp->ignore_sigint = 0;
|
||
}
|
||
}
|
||
|
||
/* Fetch the possible triggered data watchpoint info and store it in
|
||
LP.
|
||
|
||
On some archs, like x86, that use debug registers to set
|
||
watchpoints, it's possible that the way to know which watched
|
||
address trapped, is to check the register that is used to select
|
||
which address to watch. Problem is, between setting the watchpoint
|
||
and reading back which data address trapped, the user may change
|
||
the set of watchpoints, and, as a consequence, GDB changes the
|
||
debug registers in the inferior. To avoid reading back a stale
|
||
stopped-data-address when that happens, we cache in LP the fact
|
||
that a watchpoint trapped, and the corresponding data address, as
|
||
soon as we see LP stop with a SIGTRAP. If GDB changes the debug
|
||
registers meanwhile, we have the cached data we can rely on. */
|
||
|
||
static int
|
||
check_stopped_by_watchpoint (struct lwp_info *lp)
|
||
{
|
||
struct cleanup *old_chain;
|
||
|
||
if (linux_ops->to_stopped_by_watchpoint == NULL)
|
||
return 0;
|
||
|
||
old_chain = save_inferior_ptid ();
|
||
inferior_ptid = lp->ptid;
|
||
|
||
if (linux_ops->to_stopped_by_watchpoint (linux_ops))
|
||
{
|
||
lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
|
||
|
||
if (linux_ops->to_stopped_data_address != NULL)
|
||
lp->stopped_data_address_p =
|
||
linux_ops->to_stopped_data_address (¤t_target,
|
||
&lp->stopped_data_address);
|
||
else
|
||
lp->stopped_data_address_p = 0;
|
||
}
|
||
|
||
do_cleanups (old_chain);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
|
||
}
|
||
|
||
/* Called when the LWP stopped for a trap that could be explained by a
|
||
watchpoint or a breakpoint. */
|
||
|
||
static void
|
||
save_sigtrap (struct lwp_info *lp)
|
||
{
|
||
gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
|
||
gdb_assert (lp->status != 0);
|
||
|
||
/* Check first if this was a SW/HW breakpoint before checking
|
||
watchpoints, because at least s390 can't tell the data address of
|
||
hardware watchpoint hits, and the kernel returns
|
||
stopped-by-watchpoint as long as there's a watchpoint set. */
|
||
if (linux_nat_status_is_event (lp->status))
|
||
check_stopped_by_breakpoint (lp);
|
||
|
||
/* Note that TRAP_HWBKPT can indicate either a hardware breakpoint
|
||
or hardware watchpoint. Check which is which if we got
|
||
TARGET_STOPPED_BY_HW_BREAKPOINT. */
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON
|
||
|| lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
|
||
check_stopped_by_watchpoint (lp);
|
||
}
|
||
|
||
/* Returns true if the LWP had stopped for a watchpoint. */
|
||
|
||
static int
|
||
linux_nat_stopped_by_watchpoint (struct target_ops *ops)
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
|
||
}
|
||
|
||
static int
|
||
linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
*addr_p = lp->stopped_data_address;
|
||
|
||
return lp->stopped_data_address_p;
|
||
}
|
||
|
||
/* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
|
||
|
||
static int
|
||
sigtrap_is_event (int status)
|
||
{
|
||
return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
|
||
}
|
||
|
||
/* Set alternative SIGTRAP-like events recognizer. If
|
||
breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
|
||
applied. */
|
||
|
||
void
|
||
linux_nat_set_status_is_event (struct target_ops *t,
|
||
int (*status_is_event) (int status))
|
||
{
|
||
linux_nat_status_is_event = status_is_event;
|
||
}
|
||
|
||
/* Wait until LP is stopped. */
|
||
|
||
static int
|
||
stop_wait_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
struct inferior *inf = find_inferior_ptid (lp->ptid);
|
||
|
||
/* If this is a vfork parent, bail out, it is not going to report
|
||
any SIGSTOP until the vfork is done with. */
|
||
if (inf->vfork_child != NULL)
|
||
return 0;
|
||
|
||
if (!lp->stopped)
|
||
{
|
||
int status;
|
||
|
||
status = wait_lwp (lp);
|
||
if (status == 0)
|
||
return 0;
|
||
|
||
if (lp->ignore_sigint && WIFSTOPPED (status)
|
||
&& WSTOPSIG (status) == SIGINT)
|
||
{
|
||
lp->ignore_sigint = 0;
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
|
||
lp->stopped = 0;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"PTRACE_CONT %s, 0, 0 (%s) "
|
||
"(discarding SIGINT)\n",
|
||
target_pid_to_str (lp->ptid),
|
||
errno ? safe_strerror (errno) : "OK");
|
||
|
||
return stop_wait_callback (lp, NULL);
|
||
}
|
||
|
||
maybe_clear_ignore_sigint (lp);
|
||
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
/* The thread was stopped with a signal other than SIGSTOP. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SWC: Pending event %s in %s\n",
|
||
status_to_str ((int) status),
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
/* Save the sigtrap event. */
|
||
lp->status = status;
|
||
gdb_assert (lp->signalled);
|
||
save_sigtrap (lp);
|
||
}
|
||
else
|
||
{
|
||
/* We caught the SIGSTOP that we intended to catch, so
|
||
there's no SIGSTOP pending. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SWC: Expected SIGSTOP caught for %s.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
/* Reset SIGNALLED only after the stop_wait_callback call
|
||
above as it does gdb_assert on SIGNALLED. */
|
||
lp->signalled = 0;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return non-zero if LP has a wait status pending. Discard the
|
||
pending event and resume the LWP if the event that originally
|
||
caused the stop became uninteresting. */
|
||
|
||
static int
|
||
status_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
/* Only report a pending wait status if we pretend that this has
|
||
indeed been resumed. */
|
||
if (!lp->resumed)
|
||
return 0;
|
||
|
||
if (!lwp_status_pending_p (lp))
|
||
return 0;
|
||
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
|
||
|| lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
CORE_ADDR pc;
|
||
int discard = 0;
|
||
|
||
pc = regcache_read_pc (regcache);
|
||
|
||
if (pc != lp->stop_pc)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: PC of %s changed. was=%s, now=%s\n",
|
||
target_pid_to_str (lp->ptid),
|
||
paddress (target_gdbarch (), lp->stop_pc),
|
||
paddress (target_gdbarch (), pc));
|
||
discard = 1;
|
||
}
|
||
|
||
#if !USE_SIGTRAP_SIGINFO
|
||
else if (!breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: previous breakpoint of %s, at %s gone\n",
|
||
target_pid_to_str (lp->ptid),
|
||
paddress (target_gdbarch (), lp->stop_pc));
|
||
|
||
discard = 1;
|
||
}
|
||
#endif
|
||
|
||
if (discard)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: pending event of %s cancelled.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
lp->status = 0;
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Return non-zero if LP isn't stopped. */
|
||
|
||
static int
|
||
running_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
return (!lp->stopped
|
||
|| (lwp_status_pending_p (lp) && lp->resumed));
|
||
}
|
||
|
||
/* Count the LWP's that have had events. */
|
||
|
||
static int
|
||
count_events_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
int *count = data;
|
||
|
||
gdb_assert (count != NULL);
|
||
|
||
/* Select only resumed LWPs that have an event pending. */
|
||
if (lp->resumed && lwp_status_pending_p (lp))
|
||
(*count)++;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Select the LWP (if any) that is currently being single-stepped. */
|
||
|
||
static int
|
||
select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
if (lp->last_resume_kind == resume_step
|
||
&& lp->status != 0)
|
||
return 1;
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
/* Returns true if LP has a status pending. */
|
||
|
||
static int
|
||
lwp_status_pending_p (struct lwp_info *lp)
|
||
{
|
||
/* We check for lp->waitstatus in addition to lp->status, because we
|
||
can have pending process exits recorded in lp->status and
|
||
W_EXITCODE(0,0) happens to be 0. */
|
||
return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
|
||
}
|
||
|
||
/* Select the Nth LWP that has had an event. */
|
||
|
||
static int
|
||
select_event_lwp_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
int *selector = data;
|
||
|
||
gdb_assert (selector != NULL);
|
||
|
||
/* Select only resumed LWPs that have an event pending. */
|
||
if (lp->resumed && lwp_status_pending_p (lp))
|
||
if ((*selector)-- == 0)
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Called when the LWP got a signal/trap that could be explained by a
|
||
software or hardware breakpoint. */
|
||
|
||
static int
|
||
check_stopped_by_breakpoint (struct lwp_info *lp)
|
||
{
|
||
/* Arrange for a breakpoint to be hit again later. We don't keep
|
||
the SIGTRAP status and don't forward the SIGTRAP signal to the
|
||
LWP. We will handle the current event, eventually we will resume
|
||
this LWP, and this breakpoint will trap again.
|
||
|
||
If we do not do this, then we run the risk that the user will
|
||
delete or disable the breakpoint, but the LWP will have already
|
||
tripped on it. */
|
||
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
CORE_ADDR pc;
|
||
CORE_ADDR sw_bp_pc;
|
||
#if USE_SIGTRAP_SIGINFO
|
||
siginfo_t siginfo;
|
||
#endif
|
||
|
||
pc = regcache_read_pc (regcache);
|
||
sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
|
||
|
||
#if USE_SIGTRAP_SIGINFO
|
||
if (linux_nat_get_siginfo (lp->ptid, &siginfo))
|
||
{
|
||
if (siginfo.si_signo == SIGTRAP)
|
||
{
|
||
if (siginfo.si_code == GDB_ARCH_TRAP_BRKPT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by software "
|
||
"breakpoint\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
/* Back up the PC if necessary. */
|
||
if (pc != sw_bp_pc)
|
||
regcache_write_pc (regcache, sw_bp_pc);
|
||
|
||
lp->stop_pc = sw_bp_pc;
|
||
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
return 1;
|
||
}
|
||
else if (siginfo.si_code == TRAP_HWBKPT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by hardware "
|
||
"breakpoint/watchpoint\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
lp->stop_pc = pc;
|
||
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
|
||
return 1;
|
||
}
|
||
else if (siginfo.si_code == TRAP_TRACE)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by trace\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
}
|
||
}
|
||
#else
|
||
if ((!lp->step || lp->stop_pc == sw_bp_pc)
|
||
&& software_breakpoint_inserted_here_p (get_regcache_aspace (regcache),
|
||
sw_bp_pc))
|
||
{
|
||
/* The LWP was either continued, or stepped a software
|
||
breakpoint instruction. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by software breakpoint\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
/* Back up the PC if necessary. */
|
||
if (pc != sw_bp_pc)
|
||
regcache_write_pc (regcache, sw_bp_pc);
|
||
|
||
lp->stop_pc = sw_bp_pc;
|
||
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
return 1;
|
||
}
|
||
|
||
if (hardware_breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: stopped by hardware breakpoint %s\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
lp->stop_pc = pc;
|
||
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
|
||
return 1;
|
||
}
|
||
#endif
|
||
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Returns true if the LWP had stopped for a software breakpoint. */
|
||
|
||
static int
|
||
linux_nat_stopped_by_sw_breakpoint (struct target_ops *ops)
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
}
|
||
|
||
/* Implement the supports_stopped_by_sw_breakpoint method. */
|
||
|
||
static int
|
||
linux_nat_supports_stopped_by_sw_breakpoint (struct target_ops *ops)
|
||
{
|
||
return USE_SIGTRAP_SIGINFO;
|
||
}
|
||
|
||
/* Returns true if the LWP had stopped for a hardware
|
||
breakpoint/watchpoint. */
|
||
|
||
static int
|
||
linux_nat_stopped_by_hw_breakpoint (struct target_ops *ops)
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
|
||
}
|
||
|
||
/* Implement the supports_stopped_by_hw_breakpoint method. */
|
||
|
||
static int
|
||
linux_nat_supports_stopped_by_hw_breakpoint (struct target_ops *ops)
|
||
{
|
||
return USE_SIGTRAP_SIGINFO;
|
||
}
|
||
|
||
/* Select one LWP out of those that have events pending. */
|
||
|
||
static void
|
||
select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
|
||
{
|
||
int num_events = 0;
|
||
int random_selector;
|
||
struct lwp_info *event_lp = NULL;
|
||
|
||
/* Record the wait status for the original LWP. */
|
||
(*orig_lp)->status = *status;
|
||
|
||
/* In all-stop, give preference to the LWP that is being
|
||
single-stepped. There will be at most one, and it will be the
|
||
LWP that the core is most interested in. If we didn't do this,
|
||
then we'd have to handle pending step SIGTRAPs somehow in case
|
||
the core later continues the previously-stepped thread, as
|
||
otherwise we'd report the pending SIGTRAP then, and the core, not
|
||
having stepped the thread, wouldn't understand what the trap was
|
||
for, and therefore would report it to the user as a random
|
||
signal. */
|
||
if (!non_stop)
|
||
{
|
||
event_lp = iterate_over_lwps (filter,
|
||
select_singlestep_lwp_callback, NULL);
|
||
if (event_lp != NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SEL: Select single-step %s\n",
|
||
target_pid_to_str (event_lp->ptid));
|
||
}
|
||
}
|
||
|
||
if (event_lp == NULL)
|
||
{
|
||
/* Pick one at random, out of those which have had events. */
|
||
|
||
/* First see how many events we have. */
|
||
iterate_over_lwps (filter, count_events_callback, &num_events);
|
||
gdb_assert (num_events > 0);
|
||
|
||
/* Now randomly pick a LWP out of those that have had
|
||
events. */
|
||
random_selector = (int)
|
||
((num_events * (double) rand ()) / (RAND_MAX + 1.0));
|
||
|
||
if (debug_linux_nat && num_events > 1)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SEL: Found %d events, selecting #%d\n",
|
||
num_events, random_selector);
|
||
|
||
event_lp = iterate_over_lwps (filter,
|
||
select_event_lwp_callback,
|
||
&random_selector);
|
||
}
|
||
|
||
if (event_lp != NULL)
|
||
{
|
||
/* Switch the event LWP. */
|
||
*orig_lp = event_lp;
|
||
*status = event_lp->status;
|
||
}
|
||
|
||
/* Flush the wait status for the event LWP. */
|
||
(*orig_lp)->status = 0;
|
||
}
|
||
|
||
/* Return non-zero if LP has been resumed. */
|
||
|
||
static int
|
||
resumed_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
return lp->resumed;
|
||
}
|
||
|
||
/* Stop an active thread, verify it still exists, then resume it. If
|
||
the thread ends up with a pending status, then it is not resumed,
|
||
and *DATA (really a pointer to int), is set. */
|
||
|
||
static int
|
||
stop_and_resume_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
if (!lp->stopped)
|
||
{
|
||
ptid_t ptid = lp->ptid;
|
||
|
||
stop_callback (lp, NULL);
|
||
stop_wait_callback (lp, NULL);
|
||
|
||
/* Resume if the lwp still exists, and the core wanted it
|
||
running. */
|
||
lp = find_lwp_pid (ptid);
|
||
if (lp != NULL)
|
||
{
|
||
if (lp->last_resume_kind == resume_stop
|
||
&& !lwp_status_pending_p (lp))
|
||
{
|
||
/* The core wanted the LWP to stop. Even if it stopped
|
||
cleanly (with SIGSTOP), leave the event pending. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SARC: core wanted LWP %ld stopped "
|
||
"(leaving SIGSTOP pending)\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
lp->status = W_STOPCODE (SIGSTOP);
|
||
}
|
||
|
||
if (!lwp_status_pending_p (lp))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SARC: re-resuming LWP %ld\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
resume_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SARC: not re-resuming LWP %ld "
|
||
"(has pending)\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
}
|
||
}
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Check if we should go on and pass this event to common code.
|
||
Return the affected lwp if we are, or NULL otherwise. */
|
||
|
||
static struct lwp_info *
|
||
linux_nat_filter_event (int lwpid, int status)
|
||
{
|
||
struct lwp_info *lp;
|
||
int event = linux_ptrace_get_extended_event (status);
|
||
|
||
lp = find_lwp_pid (pid_to_ptid (lwpid));
|
||
|
||
/* Check for stop events reported by a process we didn't already
|
||
know about - anything not already in our LWP list.
|
||
|
||
If we're expecting to receive stopped processes after
|
||
fork, vfork, and clone events, then we'll just add the
|
||
new one to our list and go back to waiting for the event
|
||
to be reported - the stopped process might be returned
|
||
from waitpid before or after the event is.
|
||
|
||
But note the case of a non-leader thread exec'ing after the
|
||
leader having exited, and gone from our lists. The non-leader
|
||
thread changes its tid to the tgid. */
|
||
|
||
if (WIFSTOPPED (status) && lp == NULL
|
||
&& (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
|
||
{
|
||
/* A multi-thread exec after we had seen the leader exiting. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Re-adding thread group leader LWP %d.\n",
|
||
lwpid);
|
||
|
||
lp = add_lwp (ptid_build (lwpid, lwpid, 0));
|
||
lp->stopped = 1;
|
||
lp->resumed = 1;
|
||
add_thread (lp->ptid);
|
||
}
|
||
|
||
if (WIFSTOPPED (status) && !lp)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: saving LWP %ld status %s in stopped_pids list\n",
|
||
(long) lwpid, status_to_str (status));
|
||
add_to_pid_list (&stopped_pids, lwpid, status);
|
||
return NULL;
|
||
}
|
||
|
||
/* Make sure we don't report an event for the exit of an LWP not in
|
||
our list, i.e. not part of the current process. This can happen
|
||
if we detach from a program we originally forked and then it
|
||
exits. */
|
||
if (!WIFSTOPPED (status) && !lp)
|
||
return NULL;
|
||
|
||
/* This LWP is stopped now. (And if dead, this prevents it from
|
||
ever being continued.) */
|
||
lp->stopped = 1;
|
||
|
||
if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
|
||
{
|
||
struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
|
||
int options = linux_nat_ptrace_options (inf->attach_flag);
|
||
|
||
linux_enable_event_reporting (ptid_get_lwp (lp->ptid), options);
|
||
lp->must_set_ptrace_flags = 0;
|
||
}
|
||
|
||
/* Handle GNU/Linux's syscall SIGTRAPs. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
|
||
{
|
||
/* No longer need the sysgood bit. The ptrace event ends up
|
||
recorded in lp->waitstatus if we care for it. We can carry
|
||
on handling the event like a regular SIGTRAP from here
|
||
on. */
|
||
status = W_STOPCODE (SIGTRAP);
|
||
if (linux_handle_syscall_trap (lp, 0))
|
||
return NULL;
|
||
}
|
||
|
||
/* Handle GNU/Linux's extended waitstatus for trace events. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
|
||
&& linux_is_extended_waitstatus (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Handling extended status 0x%06x\n",
|
||
status);
|
||
if (linux_handle_extended_wait (lp, status, 0))
|
||
return NULL;
|
||
}
|
||
|
||
/* Check if the thread has exited. */
|
||
if (WIFEXITED (status) || WIFSIGNALED (status))
|
||
{
|
||
if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
|
||
{
|
||
/* If this is the main thread, we must stop all threads and
|
||
verify if they are still alive. This is because in the
|
||
nptl thread model on Linux 2.4, there is no signal issued
|
||
for exiting LWPs other than the main thread. We only get
|
||
the main thread exit signal once all child threads have
|
||
already exited. If we stop all the threads and use the
|
||
stop_wait_callback to check if they have exited we can
|
||
determine whether this signal should be ignored or
|
||
whether it means the end of the debugged application,
|
||
regardless of which threading model is being used. */
|
||
if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
|
||
{
|
||
iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
|
||
stop_and_resume_callback, NULL);
|
||
}
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s exited.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
|
||
{
|
||
/* If there is at least one more LWP, then the exit signal
|
||
was not the end of the debugged application and should be
|
||
ignored. */
|
||
exit_lwp (lp);
|
||
return NULL;
|
||
}
|
||
}
|
||
|
||
gdb_assert (lp->resumed);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"Process %ld exited\n",
|
||
ptid_get_lwp (lp->ptid));
|
||
|
||
/* This was the last lwp in the process. Since events are
|
||
serialized to GDB core, we may not be able report this one
|
||
right now, but GDB core and the other target layers will want
|
||
to be notified about the exit code/signal, leave the status
|
||
pending for the next time we're able to report it. */
|
||
|
||
/* Dead LWP's aren't expected to reported a pending sigstop. */
|
||
lp->signalled = 0;
|
||
|
||
/* Store the pending event in the waitstatus, because
|
||
W_EXITCODE(0,0) == 0. */
|
||
store_waitstatus (&lp->waitstatus, status);
|
||
return lp;
|
||
}
|
||
|
||
/* Check if the current LWP has previously exited. In the nptl
|
||
thread model, LWPs other than the main thread do not issue
|
||
signals when they exit so we must check whenever the thread has
|
||
stopped. A similar check is made in stop_wait_callback(). */
|
||
if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
|
||
{
|
||
ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s exited.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
exit_lwp (lp);
|
||
|
||
/* Make sure there is at least one thread running. */
|
||
gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
|
||
|
||
/* Discard the event. */
|
||
return NULL;
|
||
}
|
||
|
||
/* Make sure we don't report a SIGSTOP that we sent ourselves in
|
||
an attempt to stop an LWP. */
|
||
if (lp->signalled
|
||
&& WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
|
||
{
|
||
lp->signalled = 0;
|
||
|
||
if (lp->last_resume_kind == resume_stop)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: resume_stop SIGSTOP caught for %s.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
else
|
||
{
|
||
/* This is a delayed SIGSTOP. Filter out the event. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
|
||
lp->step ?
|
||
"PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
gdb_assert (lp->resumed);
|
||
return NULL;
|
||
}
|
||
}
|
||
|
||
/* Make sure we don't report a SIGINT that we have already displayed
|
||
for another thread. */
|
||
if (lp->ignore_sigint
|
||
&& WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Delayed SIGINT caught for %s.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
|
||
/* This is a delayed SIGINT. */
|
||
lp->ignore_sigint = 0;
|
||
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s %s, 0, 0 (discard SIGINT)\n",
|
||
lp->step ?
|
||
"PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid));
|
||
gdb_assert (lp->resumed);
|
||
|
||
/* Discard the event. */
|
||
return NULL;
|
||
}
|
||
|
||
/* Don't report signals that GDB isn't interested in, such as
|
||
signals that are neither printed nor stopped upon. Stopping all
|
||
threads can be a bit time-consuming so if we want decent
|
||
performance with heavily multi-threaded programs, especially when
|
||
they're using a high frequency timer, we'd better avoid it if we
|
||
can. */
|
||
if (WIFSTOPPED (status))
|
||
{
|
||
enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
|
||
|
||
if (!non_stop)
|
||
{
|
||
/* Only do the below in all-stop, as we currently use SIGSTOP
|
||
to implement target_stop (see linux_nat_stop) in
|
||
non-stop. */
|
||
if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
|
||
{
|
||
/* If ^C/BREAK is typed at the tty/console, SIGINT gets
|
||
forwarded to the entire process group, that is, all LWPs
|
||
will receive it - unless they're using CLONE_THREAD to
|
||
share signals. Since we only want to report it once, we
|
||
mark it as ignored for all LWPs except this one. */
|
||
iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
|
||
set_ignore_sigint, NULL);
|
||
lp->ignore_sigint = 0;
|
||
}
|
||
else
|
||
maybe_clear_ignore_sigint (lp);
|
||
}
|
||
|
||
/* When using hardware single-step, we need to report every signal.
|
||
Otherwise, signals in pass_mask may be short-circuited
|
||
except signals that might be caused by a breakpoint. */
|
||
if (!lp->step
|
||
&& WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
|
||
&& !linux_wstatus_maybe_breakpoint (status))
|
||
{
|
||
linux_resume_one_lwp (lp, lp->step, signo);
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s %s, %s (preempt 'handle')\n",
|
||
lp->step ?
|
||
"PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo))
|
||
: "0"));
|
||
return NULL;
|
||
}
|
||
}
|
||
|
||
/* An interesting event. */
|
||
gdb_assert (lp);
|
||
lp->status = status;
|
||
save_sigtrap (lp);
|
||
return lp;
|
||
}
|
||
|
||
/* Detect zombie thread group leaders, and "exit" them. We can't reap
|
||
their exits until all other threads in the group have exited. */
|
||
|
||
static void
|
||
check_zombie_leaders (void)
|
||
{
|
||
struct inferior *inf;
|
||
|
||
ALL_INFERIORS (inf)
|
||
{
|
||
struct lwp_info *leader_lp;
|
||
|
||
if (inf->pid == 0)
|
||
continue;
|
||
|
||
leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
|
||
if (leader_lp != NULL
|
||
/* Check if there are other threads in the group, as we may
|
||
have raced with the inferior simply exiting. */
|
||
&& num_lwps (inf->pid) > 1
|
||
&& linux_proc_pid_is_zombie (inf->pid))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CZL: Thread group leader %d zombie "
|
||
"(it exited, or another thread execd).\n",
|
||
inf->pid);
|
||
|
||
/* A leader zombie can mean one of two things:
|
||
|
||
- It exited, and there's an exit status pending
|
||
available, or only the leader exited (not the whole
|
||
program). In the latter case, we can't waitpid the
|
||
leader's exit status until all other threads are gone.
|
||
|
||
- There are 3 or more threads in the group, and a thread
|
||
other than the leader exec'd. On an exec, the Linux
|
||
kernel destroys all other threads (except the execing
|
||
one) in the thread group, and resets the execing thread's
|
||
tid to the tgid. No exit notification is sent for the
|
||
execing thread -- from the ptracer's perspective, it
|
||
appears as though the execing thread just vanishes.
|
||
Until we reap all other threads except the leader and the
|
||
execing thread, the leader will be zombie, and the
|
||
execing thread will be in `D (disc sleep)'. As soon as
|
||
all other threads are reaped, the execing thread changes
|
||
it's tid to the tgid, and the previous (zombie) leader
|
||
vanishes, giving place to the "new" leader. We could try
|
||
distinguishing the exit and exec cases, by waiting once
|
||
more, and seeing if something comes out, but it doesn't
|
||
sound useful. The previous leader _does_ go away, and
|
||
we'll re-add the new one once we see the exec event
|
||
(which is just the same as what would happen if the
|
||
previous leader did exit voluntarily before some other
|
||
thread execs). */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CZL: Thread group leader %d vanished.\n",
|
||
inf->pid);
|
||
exit_lwp (leader_lp);
|
||
}
|
||
}
|
||
}
|
||
|
||
static ptid_t
|
||
linux_nat_wait_1 (struct target_ops *ops,
|
||
ptid_t ptid, struct target_waitstatus *ourstatus,
|
||
int target_options)
|
||
{
|
||
sigset_t prev_mask;
|
||
enum resume_kind last_resume_kind;
|
||
struct lwp_info *lp;
|
||
int status;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
|
||
|
||
/* The first time we get here after starting a new inferior, we may
|
||
not have added it to the LWP list yet - this is the earliest
|
||
moment at which we know its PID. */
|
||
if (ptid_is_pid (inferior_ptid))
|
||
{
|
||
/* Upgrade the main thread's ptid. */
|
||
thread_change_ptid (inferior_ptid,
|
||
ptid_build (ptid_get_pid (inferior_ptid),
|
||
ptid_get_pid (inferior_ptid), 0));
|
||
|
||
lp = add_initial_lwp (inferior_ptid);
|
||
lp->resumed = 1;
|
||
}
|
||
|
||
/* Make sure SIGCHLD is blocked until the sigsuspend below. */
|
||
block_child_signals (&prev_mask);
|
||
|
||
/* First check if there is a LWP with a wait status pending. */
|
||
lp = iterate_over_lwps (ptid, status_callback, NULL);
|
||
if (lp != NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Using pending wait status %s for %s.\n",
|
||
status_to_str (lp->status),
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
|
||
if (!target_is_async_p ())
|
||
{
|
||
/* Causes SIGINT to be passed on to the attached process. */
|
||
set_sigint_trap ();
|
||
}
|
||
|
||
/* But if we don't find a pending event, we'll have to wait. Always
|
||
pull all events out of the kernel. We'll randomly select an
|
||
event LWP out of all that have events, to prevent starvation. */
|
||
|
||
while (lp == NULL)
|
||
{
|
||
pid_t lwpid;
|
||
|
||
/* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
|
||
quirks:
|
||
|
||
- If the thread group leader exits while other threads in the
|
||
thread group still exist, waitpid(TGID, ...) hangs. That
|
||
waitpid won't return an exit status until the other threads
|
||
in the group are reapped.
|
||
|
||
- When a non-leader thread execs, that thread just vanishes
|
||
without reporting an exit (so we'd hang if we waited for it
|
||
explicitly in that case). The exec event is reported to
|
||
the TGID pid. */
|
||
|
||
errno = 0;
|
||
lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
|
||
if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
|
||
lwpid = my_waitpid (-1, &status, WNOHANG);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNW: waitpid(-1, ...) returned %d, %s\n",
|
||
lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
|
||
|
||
if (lwpid > 0)
|
||
{
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: waitpid %ld received %s\n",
|
||
(long) lwpid, status_to_str (status));
|
||
}
|
||
|
||
linux_nat_filter_event (lwpid, status);
|
||
/* Retry until nothing comes out of waitpid. A single
|
||
SIGCHLD can indicate more than one child stopped. */
|
||
continue;
|
||
}
|
||
|
||
/* Now that we've pulled all events out of the kernel, resume
|
||
LWPs that don't have an interesting event to report. */
|
||
iterate_over_lwps (minus_one_ptid,
|
||
resume_stopped_resumed_lwps, &minus_one_ptid);
|
||
|
||
/* ... and find an LWP with a status to report to the core, if
|
||
any. */
|
||
lp = iterate_over_lwps (ptid, status_callback, NULL);
|
||
if (lp != NULL)
|
||
break;
|
||
|
||
/* Check for zombie thread group leaders. Those can't be reaped
|
||
until all other threads in the thread group are. */
|
||
check_zombie_leaders ();
|
||
|
||
/* If there are no resumed children left, bail. We'd be stuck
|
||
forever in the sigsuspend call below otherwise. */
|
||
if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
|
||
|
||
if (!target_is_async_p ())
|
||
clear_sigint_trap ();
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
return minus_one_ptid;
|
||
}
|
||
|
||
/* No interesting event to report to the core. */
|
||
|
||
if (target_options & TARGET_WNOHANG)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_IGNORE;
|
||
restore_child_signals_mask (&prev_mask);
|
||
return minus_one_ptid;
|
||
}
|
||
|
||
/* We shouldn't end up here unless we want to try again. */
|
||
gdb_assert (lp == NULL);
|
||
|
||
/* Block until we get an event reported with SIGCHLD. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
|
||
sigsuspend (&suspend_mask);
|
||
}
|
||
|
||
if (!target_is_async_p ())
|
||
clear_sigint_trap ();
|
||
|
||
gdb_assert (lp);
|
||
|
||
status = lp->status;
|
||
lp->status = 0;
|
||
|
||
if (!non_stop)
|
||
{
|
||
/* Now stop all other LWP's ... */
|
||
iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
|
||
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
|
||
}
|
||
|
||
/* If we're not waiting for a specific LWP, choose an event LWP from
|
||
among those that have had events. Giving equal priority to all
|
||
LWPs that have had events helps prevent starvation. */
|
||
if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
|
||
select_event_lwp (ptid, &lp, &status);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
/* Now that we've selected our final event LWP, un-adjust its PC if
|
||
it was a software breakpoint, and we can't reliably support the
|
||
"stopped by software breakpoint" stop reason. */
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
|
||
&& !USE_SIGTRAP_SIGINFO)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
|
||
|
||
if (decr_pc != 0)
|
||
{
|
||
CORE_ADDR pc;
|
||
|
||
pc = regcache_read_pc (regcache);
|
||
regcache_write_pc (regcache, pc + decr_pc);
|
||
}
|
||
}
|
||
|
||
/* We'll need this to determine whether to report a SIGSTOP as
|
||
GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
|
||
clears it. */
|
||
last_resume_kind = lp->last_resume_kind;
|
||
|
||
if (!non_stop)
|
||
{
|
||
/* In all-stop, from the core's perspective, all LWPs are now
|
||
stopped until a new resume action is sent over. */
|
||
iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
|
||
}
|
||
else
|
||
{
|
||
resume_clear_callback (lp, NULL);
|
||
}
|
||
|
||
if (linux_nat_status_is_event (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: trap ptid is %s.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
}
|
||
|
||
if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
|
||
{
|
||
*ourstatus = lp->waitstatus;
|
||
lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
|
||
}
|
||
else
|
||
store_waitstatus (ourstatus, status);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
|
||
if (last_resume_kind == resume_stop
|
||
&& ourstatus->kind == TARGET_WAITKIND_STOPPED
|
||
&& WSTOPSIG (status) == SIGSTOP)
|
||
{
|
||
/* A thread that has been requested to stop by GDB with
|
||
target_stop, and it stopped cleanly, so report as SIG0. The
|
||
use of SIGSTOP is an implementation detail. */
|
||
ourstatus->value.sig = GDB_SIGNAL_0;
|
||
}
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXITED
|
||
|| ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
|
||
lp->core = -1;
|
||
else
|
||
lp->core = linux_common_core_of_thread (lp->ptid);
|
||
|
||
return lp->ptid;
|
||
}
|
||
|
||
/* Resume LWPs that are currently stopped without any pending status
|
||
to report, but are resumed from the core's perspective. */
|
||
|
||
static int
|
||
resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
|
||
{
|
||
ptid_t *wait_ptid_p = data;
|
||
|
||
if (lp->stopped
|
||
&& lp->resumed
|
||
&& !lwp_status_pending_p (lp))
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
|
||
TRY
|
||
{
|
||
CORE_ADDR pc = regcache_read_pc (regcache);
|
||
int leave_stopped = 0;
|
||
|
||
/* Don't bother if there's a breakpoint at PC that we'd hit
|
||
immediately, and we're not waiting for this LWP. */
|
||
if (!ptid_match (lp->ptid, *wait_ptid_p))
|
||
{
|
||
if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
|
||
leave_stopped = 1;
|
||
}
|
||
|
||
if (!leave_stopped)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RSRL: resuming stopped-resumed LWP %s at "
|
||
"%s: step=%d\n",
|
||
target_pid_to_str (lp->ptid),
|
||
paddress (gdbarch, pc),
|
||
lp->step);
|
||
|
||
linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
|
||
}
|
||
}
|
||
CATCH (ex, RETURN_MASK_ERROR)
|
||
{
|
||
if (!check_ptrace_stopped_lwp_gone (lp))
|
||
throw_exception (ex);
|
||
}
|
||
END_CATCH
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static ptid_t
|
||
linux_nat_wait (struct target_ops *ops,
|
||
ptid_t ptid, struct target_waitstatus *ourstatus,
|
||
int target_options)
|
||
{
|
||
ptid_t event_ptid;
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
char *options_string;
|
||
|
||
options_string = target_options_to_string (target_options);
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"linux_nat_wait: [%s], [%s]\n",
|
||
target_pid_to_str (ptid),
|
||
options_string);
|
||
xfree (options_string);
|
||
}
|
||
|
||
/* Flush the async file first. */
|
||
if (target_is_async_p ())
|
||
async_file_flush ();
|
||
|
||
/* Resume LWPs that are currently stopped without any pending status
|
||
to report, but are resumed from the core's perspective. LWPs get
|
||
in this state if we find them stopping at a time we're not
|
||
interested in reporting the event (target_wait on a
|
||
specific_process, for example, see linux_nat_wait_1), and
|
||
meanwhile the event became uninteresting. Don't bother resuming
|
||
LWPs we're not going to wait for if they'd stop immediately. */
|
||
if (non_stop)
|
||
iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
|
||
|
||
event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
|
||
|
||
/* If we requested any event, and something came out, assume there
|
||
may be more. If we requested a specific lwp or process, also
|
||
assume there may be more. */
|
||
if (target_is_async_p ()
|
||
&& ((ourstatus->kind != TARGET_WAITKIND_IGNORE
|
||
&& ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
|
||
|| !ptid_equal (ptid, minus_one_ptid)))
|
||
async_file_mark ();
|
||
|
||
return event_ptid;
|
||
}
|
||
|
||
static int
|
||
kill_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
/* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
|
||
|
||
errno = 0;
|
||
kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
|
||
if (debug_linux_nat)
|
||
{
|
||
int save_errno = errno;
|
||
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
|
||
target_pid_to_str (lp->ptid),
|
||
save_errno ? safe_strerror (save_errno) : "OK");
|
||
}
|
||
|
||
/* Some kernels ignore even SIGKILL for processes under ptrace. */
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
|
||
if (debug_linux_nat)
|
||
{
|
||
int save_errno = errno;
|
||
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KC: PTRACE_KILL %s, 0, 0 (%s)\n",
|
||
target_pid_to_str (lp->ptid),
|
||
save_errno ? safe_strerror (save_errno) : "OK");
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
kill_wait_callback (struct lwp_info *lp, void *data)
|
||
{
|
||
pid_t pid;
|
||
|
||
/* We must make sure that there are no pending events (delayed
|
||
SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
|
||
program doesn't interfere with any following debugging session. */
|
||
|
||
/* For cloned processes we must check both with __WCLONE and
|
||
without, since the exit status of a cloned process isn't reported
|
||
with __WCLONE. */
|
||
if (lp->cloned)
|
||
{
|
||
do
|
||
{
|
||
pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
|
||
if (pid != (pid_t) -1)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KWC: wait %s received unknown.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
/* The Linux kernel sometimes fails to kill a thread
|
||
completely after PTRACE_KILL; that goes from the stop
|
||
point in do_fork out to the one in
|
||
get_signal_to_deliever and waits again. So kill it
|
||
again. */
|
||
kill_callback (lp, NULL);
|
||
}
|
||
}
|
||
while (pid == ptid_get_lwp (lp->ptid));
|
||
|
||
gdb_assert (pid == -1 && errno == ECHILD);
|
||
}
|
||
|
||
do
|
||
{
|
||
pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
|
||
if (pid != (pid_t) -1)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KWC: wait %s received unk.\n",
|
||
target_pid_to_str (lp->ptid));
|
||
/* See the call to kill_callback above. */
|
||
kill_callback (lp, NULL);
|
||
}
|
||
}
|
||
while (pid == ptid_get_lwp (lp->ptid));
|
||
|
||
gdb_assert (pid == -1 && errno == ECHILD);
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
linux_nat_kill (struct target_ops *ops)
|
||
{
|
||
struct target_waitstatus last;
|
||
ptid_t last_ptid;
|
||
int status;
|
||
|
||
/* If we're stopped while forking and we haven't followed yet,
|
||
kill the other task. We need to do this first because the
|
||
parent will be sleeping if this is a vfork. */
|
||
|
||
get_last_target_status (&last_ptid, &last);
|
||
|
||
if (last.kind == TARGET_WAITKIND_FORKED
|
||
|| last.kind == TARGET_WAITKIND_VFORKED)
|
||
{
|
||
ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
|
||
wait (&status);
|
||
|
||
/* Let the arch-specific native code know this process is
|
||
gone. */
|
||
linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
|
||
}
|
||
|
||
if (forks_exist_p ())
|
||
linux_fork_killall ();
|
||
else
|
||
{
|
||
ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
|
||
|
||
/* Stop all threads before killing them, since ptrace requires
|
||
that the thread is stopped to sucessfully PTRACE_KILL. */
|
||
iterate_over_lwps (ptid, stop_callback, NULL);
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (ptid, stop_wait_callback, NULL);
|
||
|
||
/* Kill all LWP's ... */
|
||
iterate_over_lwps (ptid, kill_callback, NULL);
|
||
|
||
/* ... and wait until we've flushed all events. */
|
||
iterate_over_lwps (ptid, kill_wait_callback, NULL);
|
||
}
|
||
|
||
target_mourn_inferior ();
|
||
}
|
||
|
||
static void
|
||
linux_nat_mourn_inferior (struct target_ops *ops)
|
||
{
|
||
int pid = ptid_get_pid (inferior_ptid);
|
||
|
||
purge_lwp_list (pid);
|
||
|
||
if (! forks_exist_p ())
|
||
/* Normal case, no other forks available. */
|
||
linux_ops->to_mourn_inferior (ops);
|
||
else
|
||
/* Multi-fork case. The current inferior_ptid has exited, but
|
||
there are other viable forks to debug. Delete the exiting
|
||
one and context-switch to the first available. */
|
||
linux_fork_mourn_inferior ();
|
||
|
||
/* Let the arch-specific native code know this process is gone. */
|
||
linux_nat_forget_process (pid);
|
||
}
|
||
|
||
/* Convert a native/host siginfo object, into/from the siginfo in the
|
||
layout of the inferiors' architecture. */
|
||
|
||
static void
|
||
siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
|
||
{
|
||
int done = 0;
|
||
|
||
if (linux_nat_siginfo_fixup != NULL)
|
||
done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
|
||
|
||
/* If there was no callback, or the callback didn't do anything,
|
||
then just do a straight memcpy. */
|
||
if (!done)
|
||
{
|
||
if (direction == 1)
|
||
memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
|
||
else
|
||
memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
|
||
}
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
|
||
ULONGEST *xfered_len)
|
||
{
|
||
int pid;
|
||
siginfo_t siginfo;
|
||
gdb_byte inf_siginfo[sizeof (siginfo_t)];
|
||
|
||
gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
|
||
gdb_assert (readbuf || writebuf);
|
||
|
||
pid = ptid_get_lwp (inferior_ptid);
|
||
if (pid == 0)
|
||
pid = ptid_get_pid (inferior_ptid);
|
||
|
||
if (offset > sizeof (siginfo))
|
||
return TARGET_XFER_E_IO;
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
|
||
if (errno != 0)
|
||
return TARGET_XFER_E_IO;
|
||
|
||
/* When GDB is built as a 64-bit application, ptrace writes into
|
||
SIGINFO an object with 64-bit layout. Since debugging a 32-bit
|
||
inferior with a 64-bit GDB should look the same as debugging it
|
||
with a 32-bit GDB, we need to convert it. GDB core always sees
|
||
the converted layout, so any read/write will have to be done
|
||
post-conversion. */
|
||
siginfo_fixup (&siginfo, inf_siginfo, 0);
|
||
|
||
if (offset + len > sizeof (siginfo))
|
||
len = sizeof (siginfo) - offset;
|
||
|
||
if (readbuf != NULL)
|
||
memcpy (readbuf, inf_siginfo + offset, len);
|
||
else
|
||
{
|
||
memcpy (inf_siginfo + offset, writebuf, len);
|
||
|
||
/* Convert back to ptrace layout before flushing it out. */
|
||
siginfo_fixup (&siginfo, inf_siginfo, 1);
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
|
||
if (errno != 0)
|
||
return TARGET_XFER_E_IO;
|
||
}
|
||
|
||
*xfered_len = len;
|
||
return TARGET_XFER_OK;
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf,
|
||
ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
|
||
{
|
||
struct cleanup *old_chain;
|
||
enum target_xfer_status xfer;
|
||
|
||
if (object == TARGET_OBJECT_SIGNAL_INFO)
|
||
return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
/* The target is connected but no live inferior is selected. Pass
|
||
this request down to a lower stratum (e.g., the executable
|
||
file). */
|
||
if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
|
||
return TARGET_XFER_EOF;
|
||
|
||
old_chain = save_inferior_ptid ();
|
||
|
||
if (ptid_lwp_p (inferior_ptid))
|
||
inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
|
||
|
||
xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
do_cleanups (old_chain);
|
||
return xfer;
|
||
}
|
||
|
||
static int
|
||
linux_thread_alive (ptid_t ptid)
|
||
{
|
||
int err, tmp_errno;
|
||
|
||
gdb_assert (ptid_lwp_p (ptid));
|
||
|
||
/* Send signal 0 instead of anything ptrace, because ptracing a
|
||
running thread errors out claiming that the thread doesn't
|
||
exist. */
|
||
err = kill_lwp (ptid_get_lwp (ptid), 0);
|
||
tmp_errno = errno;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLTA: KILL(SIG0) %s (%s)\n",
|
||
target_pid_to_str (ptid),
|
||
err ? safe_strerror (tmp_errno) : "OK");
|
||
|
||
if (err != 0)
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int
|
||
linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
|
||
{
|
||
return linux_thread_alive (ptid);
|
||
}
|
||
|
||
/* Implement the to_update_thread_list target method for this
|
||
target. */
|
||
|
||
static void
|
||
linux_nat_update_thread_list (struct target_ops *ops)
|
||
{
|
||
if (linux_supports_traceclone ())
|
||
{
|
||
/* With support for clone events, we add/delete threads from the
|
||
list as clone/exit events are processed, so just try deleting
|
||
exited threads still in the thread list. */
|
||
delete_exited_threads ();
|
||
}
|
||
else
|
||
prune_threads ();
|
||
}
|
||
|
||
static char *
|
||
linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
|
||
{
|
||
static char buf[64];
|
||
|
||
if (ptid_lwp_p (ptid)
|
||
&& (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
|
||
|| num_lwps (ptid_get_pid (ptid)) > 1))
|
||
{
|
||
snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
|
||
return buf;
|
||
}
|
||
|
||
return normal_pid_to_str (ptid);
|
||
}
|
||
|
||
static char *
|
||
linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
|
||
{
|
||
int pid = ptid_get_pid (thr->ptid);
|
||
long lwp = ptid_get_lwp (thr->ptid);
|
||
#define FORMAT "/proc/%d/task/%ld/comm"
|
||
char buf[sizeof (FORMAT) + 30];
|
||
FILE *comm_file;
|
||
char *result = NULL;
|
||
|
||
snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
|
||
comm_file = gdb_fopen_cloexec (buf, "r");
|
||
if (comm_file)
|
||
{
|
||
/* Not exported by the kernel, so we define it here. */
|
||
#define COMM_LEN 16
|
||
static char line[COMM_LEN + 1];
|
||
|
||
if (fgets (line, sizeof (line), comm_file))
|
||
{
|
||
char *nl = strchr (line, '\n');
|
||
|
||
if (nl)
|
||
*nl = '\0';
|
||
if (*line != '\0')
|
||
result = line;
|
||
}
|
||
|
||
fclose (comm_file);
|
||
}
|
||
|
||
#undef COMM_LEN
|
||
#undef FORMAT
|
||
|
||
return result;
|
||
}
|
||
|
||
/* Accepts an integer PID; Returns a string representing a file that
|
||
can be opened to get the symbols for the child process. */
|
||
|
||
static char *
|
||
linux_child_pid_to_exec_file (struct target_ops *self, int pid)
|
||
{
|
||
return linux_proc_pid_to_exec_file (pid);
|
||
}
|
||
|
||
/* Implement the to_xfer_partial interface for memory reads using the /proc
|
||
filesystem. Because we can use a single read() call for /proc, this
|
||
can be much more efficient than banging away at PTRACE_PEEKTEXT,
|
||
but it doesn't support writes. */
|
||
|
||
static enum target_xfer_status
|
||
linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf,
|
||
ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
|
||
{
|
||
LONGEST ret;
|
||
int fd;
|
||
char filename[64];
|
||
|
||
if (object != TARGET_OBJECT_MEMORY || !readbuf)
|
||
return 0;
|
||
|
||
/* Don't bother for one word. */
|
||
if (len < 3 * sizeof (long))
|
||
return TARGET_XFER_EOF;
|
||
|
||
/* We could keep this file open and cache it - possibly one per
|
||
thread. That requires some juggling, but is even faster. */
|
||
xsnprintf (filename, sizeof filename, "/proc/%d/mem",
|
||
ptid_get_pid (inferior_ptid));
|
||
fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
|
||
if (fd == -1)
|
||
return TARGET_XFER_EOF;
|
||
|
||
/* If pread64 is available, use it. It's faster if the kernel
|
||
supports it (only one syscall), and it's 64-bit safe even on
|
||
32-bit platforms (for instance, SPARC debugging a SPARC64
|
||
application). */
|
||
#ifdef HAVE_PREAD64
|
||
if (pread64 (fd, readbuf, len, offset) != len)
|
||
#else
|
||
if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
|
||
#endif
|
||
ret = 0;
|
||
else
|
||
ret = len;
|
||
|
||
close (fd);
|
||
|
||
if (ret == 0)
|
||
return TARGET_XFER_EOF;
|
||
else
|
||
{
|
||
*xfered_len = ret;
|
||
return TARGET_XFER_OK;
|
||
}
|
||
}
|
||
|
||
|
||
/* Enumerate spufs IDs for process PID. */
|
||
static LONGEST
|
||
spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
|
||
{
|
||
enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
|
||
LONGEST pos = 0;
|
||
LONGEST written = 0;
|
||
char path[128];
|
||
DIR *dir;
|
||
struct dirent *entry;
|
||
|
||
xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
|
||
dir = opendir (path);
|
||
if (!dir)
|
||
return -1;
|
||
|
||
rewinddir (dir);
|
||
while ((entry = readdir (dir)) != NULL)
|
||
{
|
||
struct stat st;
|
||
struct statfs stfs;
|
||
int fd;
|
||
|
||
fd = atoi (entry->d_name);
|
||
if (!fd)
|
||
continue;
|
||
|
||
xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
|
||
if (stat (path, &st) != 0)
|
||
continue;
|
||
if (!S_ISDIR (st.st_mode))
|
||
continue;
|
||
|
||
if (statfs (path, &stfs) != 0)
|
||
continue;
|
||
if (stfs.f_type != SPUFS_MAGIC)
|
||
continue;
|
||
|
||
if (pos >= offset && pos + 4 <= offset + len)
|
||
{
|
||
store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
|
||
written += 4;
|
||
}
|
||
pos += 4;
|
||
}
|
||
|
||
closedir (dir);
|
||
return written;
|
||
}
|
||
|
||
/* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
|
||
object type, using the /proc file system. */
|
||
|
||
static enum target_xfer_status
|
||
linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf,
|
||
ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
|
||
{
|
||
char buf[128];
|
||
int fd = 0;
|
||
int ret = -1;
|
||
int pid = ptid_get_pid (inferior_ptid);
|
||
|
||
if (!annex)
|
||
{
|
||
if (!readbuf)
|
||
return TARGET_XFER_E_IO;
|
||
else
|
||
{
|
||
LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
|
||
|
||
if (l < 0)
|
||
return TARGET_XFER_E_IO;
|
||
else if (l == 0)
|
||
return TARGET_XFER_EOF;
|
||
else
|
||
{
|
||
*xfered_len = (ULONGEST) l;
|
||
return TARGET_XFER_OK;
|
||
}
|
||
}
|
||
}
|
||
|
||
xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
|
||
fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
|
||
if (fd <= 0)
|
||
return TARGET_XFER_E_IO;
|
||
|
||
if (offset != 0
|
||
&& lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
|
||
{
|
||
close (fd);
|
||
return TARGET_XFER_EOF;
|
||
}
|
||
|
||
if (writebuf)
|
||
ret = write (fd, writebuf, (size_t) len);
|
||
else if (readbuf)
|
||
ret = read (fd, readbuf, (size_t) len);
|
||
|
||
close (fd);
|
||
|
||
if (ret < 0)
|
||
return TARGET_XFER_E_IO;
|
||
else if (ret == 0)
|
||
return TARGET_XFER_EOF;
|
||
else
|
||
{
|
||
*xfered_len = (ULONGEST) ret;
|
||
return TARGET_XFER_OK;
|
||
}
|
||
}
|
||
|
||
|
||
/* Parse LINE as a signal set and add its set bits to SIGS. */
|
||
|
||
static void
|
||
add_line_to_sigset (const char *line, sigset_t *sigs)
|
||
{
|
||
int len = strlen (line) - 1;
|
||
const char *p;
|
||
int signum;
|
||
|
||
if (line[len] != '\n')
|
||
error (_("Could not parse signal set: %s"), line);
|
||
|
||
p = line;
|
||
signum = len * 4;
|
||
while (len-- > 0)
|
||
{
|
||
int digit;
|
||
|
||
if (*p >= '0' && *p <= '9')
|
||
digit = *p - '0';
|
||
else if (*p >= 'a' && *p <= 'f')
|
||
digit = *p - 'a' + 10;
|
||
else
|
||
error (_("Could not parse signal set: %s"), line);
|
||
|
||
signum -= 4;
|
||
|
||
if (digit & 1)
|
||
sigaddset (sigs, signum + 1);
|
||
if (digit & 2)
|
||
sigaddset (sigs, signum + 2);
|
||
if (digit & 4)
|
||
sigaddset (sigs, signum + 3);
|
||
if (digit & 8)
|
||
sigaddset (sigs, signum + 4);
|
||
|
||
p++;
|
||
}
|
||
}
|
||
|
||
/* Find process PID's pending signals from /proc/pid/status and set
|
||
SIGS to match. */
|
||
|
||
void
|
||
linux_proc_pending_signals (int pid, sigset_t *pending,
|
||
sigset_t *blocked, sigset_t *ignored)
|
||
{
|
||
FILE *procfile;
|
||
char buffer[PATH_MAX], fname[PATH_MAX];
|
||
struct cleanup *cleanup;
|
||
|
||
sigemptyset (pending);
|
||
sigemptyset (blocked);
|
||
sigemptyset (ignored);
|
||
xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
|
||
procfile = gdb_fopen_cloexec (fname, "r");
|
||
if (procfile == NULL)
|
||
error (_("Could not open %s"), fname);
|
||
cleanup = make_cleanup_fclose (procfile);
|
||
|
||
while (fgets (buffer, PATH_MAX, procfile) != NULL)
|
||
{
|
||
/* Normal queued signals are on the SigPnd line in the status
|
||
file. However, 2.6 kernels also have a "shared" pending
|
||
queue for delivering signals to a thread group, so check for
|
||
a ShdPnd line also.
|
||
|
||
Unfortunately some Red Hat kernels include the shared pending
|
||
queue but not the ShdPnd status field. */
|
||
|
||
if (startswith (buffer, "SigPnd:\t"))
|
||
add_line_to_sigset (buffer + 8, pending);
|
||
else if (startswith (buffer, "ShdPnd:\t"))
|
||
add_line_to_sigset (buffer + 8, pending);
|
||
else if (startswith (buffer, "SigBlk:\t"))
|
||
add_line_to_sigset (buffer + 8, blocked);
|
||
else if (startswith (buffer, "SigIgn:\t"))
|
||
add_line_to_sigset (buffer + 8, ignored);
|
||
}
|
||
|
||
do_cleanups (cleanup);
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
|
||
ULONGEST *xfered_len)
|
||
{
|
||
gdb_assert (object == TARGET_OBJECT_OSDATA);
|
||
|
||
*xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
|
||
if (*xfered_len == 0)
|
||
return TARGET_XFER_EOF;
|
||
else
|
||
return TARGET_XFER_OK;
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_xfer_partial (struct target_ops *ops, enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
|
||
ULONGEST *xfered_len)
|
||
{
|
||
enum target_xfer_status xfer;
|
||
|
||
if (object == TARGET_OBJECT_AUXV)
|
||
return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
if (object == TARGET_OBJECT_OSDATA)
|
||
return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
if (object == TARGET_OBJECT_SPU)
|
||
return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
/* GDB calculates all the addresses in possibly larget width of the address.
|
||
Address width needs to be masked before its final use - either by
|
||
linux_proc_xfer_partial or inf_ptrace_xfer_partial.
|
||
|
||
Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
|
||
|
||
if (object == TARGET_OBJECT_MEMORY)
|
||
{
|
||
int addr_bit = gdbarch_addr_bit (target_gdbarch ());
|
||
|
||
if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
|
||
offset &= ((ULONGEST) 1 << addr_bit) - 1;
|
||
}
|
||
|
||
xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
if (xfer != TARGET_XFER_EOF)
|
||
return xfer;
|
||
|
||
return super_xfer_partial (ops, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
}
|
||
|
||
static void
|
||
cleanup_target_stop (void *arg)
|
||
{
|
||
ptid_t *ptid = (ptid_t *) arg;
|
||
|
||
gdb_assert (arg != NULL);
|
||
|
||
/* Unpause all */
|
||
target_resume (*ptid, 0, GDB_SIGNAL_0);
|
||
}
|
||
|
||
static VEC(static_tracepoint_marker_p) *
|
||
linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
|
||
const char *strid)
|
||
{
|
||
char s[IPA_CMD_BUF_SIZE];
|
||
struct cleanup *old_chain;
|
||
int pid = ptid_get_pid (inferior_ptid);
|
||
VEC(static_tracepoint_marker_p) *markers = NULL;
|
||
struct static_tracepoint_marker *marker = NULL;
|
||
char *p = s;
|
||
ptid_t ptid = ptid_build (pid, 0, 0);
|
||
|
||
/* Pause all */
|
||
target_stop (ptid);
|
||
|
||
memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
|
||
s[sizeof ("qTfSTM")] = 0;
|
||
|
||
agent_run_command (pid, s, strlen (s) + 1);
|
||
|
||
old_chain = make_cleanup (free_current_marker, &marker);
|
||
make_cleanup (cleanup_target_stop, &ptid);
|
||
|
||
while (*p++ == 'm')
|
||
{
|
||
if (marker == NULL)
|
||
marker = XCNEW (struct static_tracepoint_marker);
|
||
|
||
do
|
||
{
|
||
parse_static_tracepoint_marker_definition (p, &p, marker);
|
||
|
||
if (strid == NULL || strcmp (strid, marker->str_id) == 0)
|
||
{
|
||
VEC_safe_push (static_tracepoint_marker_p,
|
||
markers, marker);
|
||
marker = NULL;
|
||
}
|
||
else
|
||
{
|
||
release_static_tracepoint_marker (marker);
|
||
memset (marker, 0, sizeof (*marker));
|
||
}
|
||
}
|
||
while (*p++ == ','); /* comma-separated list */
|
||
|
||
memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
|
||
s[sizeof ("qTsSTM")] = 0;
|
||
agent_run_command (pid, s, strlen (s) + 1);
|
||
p = s;
|
||
}
|
||
|
||
do_cleanups (old_chain);
|
||
|
||
return markers;
|
||
}
|
||
|
||
/* Create a prototype generic GNU/Linux target. The client can override
|
||
it with local methods. */
|
||
|
||
static void
|
||
linux_target_install_ops (struct target_ops *t)
|
||
{
|
||
t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
|
||
t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
|
||
t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
|
||
t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
|
||
t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
|
||
t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
|
||
t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
|
||
t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
|
||
t->to_post_startup_inferior = linux_child_post_startup_inferior;
|
||
t->to_post_attach = linux_child_post_attach;
|
||
t->to_follow_fork = linux_child_follow_fork;
|
||
|
||
super_xfer_partial = t->to_xfer_partial;
|
||
t->to_xfer_partial = linux_xfer_partial;
|
||
|
||
t->to_static_tracepoint_markers_by_strid
|
||
= linux_child_static_tracepoint_markers_by_strid;
|
||
}
|
||
|
||
struct target_ops *
|
||
linux_target (void)
|
||
{
|
||
struct target_ops *t;
|
||
|
||
t = inf_ptrace_target ();
|
||
linux_target_install_ops (t);
|
||
|
||
return t;
|
||
}
|
||
|
||
struct target_ops *
|
||
linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
|
||
{
|
||
struct target_ops *t;
|
||
|
||
t = inf_ptrace_trad_target (register_u_offset);
|
||
linux_target_install_ops (t);
|
||
|
||
return t;
|
||
}
|
||
|
||
/* target_is_async_p implementation. */
|
||
|
||
static int
|
||
linux_nat_is_async_p (struct target_ops *ops)
|
||
{
|
||
return linux_is_async_p ();
|
||
}
|
||
|
||
/* target_can_async_p implementation. */
|
||
|
||
static int
|
||
linux_nat_can_async_p (struct target_ops *ops)
|
||
{
|
||
/* NOTE: palves 2008-03-21: We're only async when the user requests
|
||
it explicitly with the "set target-async" command.
|
||
Someday, linux will always be async. */
|
||
return target_async_permitted;
|
||
}
|
||
|
||
static int
|
||
linux_nat_supports_non_stop (struct target_ops *self)
|
||
{
|
||
return 1;
|
||
}
|
||
|
||
/* True if we want to support multi-process. To be removed when GDB
|
||
supports multi-exec. */
|
||
|
||
int linux_multi_process = 1;
|
||
|
||
static int
|
||
linux_nat_supports_multi_process (struct target_ops *self)
|
||
{
|
||
return linux_multi_process;
|
||
}
|
||
|
||
static int
|
||
linux_nat_supports_disable_randomization (struct target_ops *self)
|
||
{
|
||
#ifdef HAVE_PERSONALITY
|
||
return 1;
|
||
#else
|
||
return 0;
|
||
#endif
|
||
}
|
||
|
||
static int async_terminal_is_ours = 1;
|
||
|
||
/* target_terminal_inferior implementation.
|
||
|
||
This is a wrapper around child_terminal_inferior to add async support. */
|
||
|
||
static void
|
||
linux_nat_terminal_inferior (struct target_ops *self)
|
||
{
|
||
/* Like target_terminal_inferior, use target_can_async_p, not
|
||
target_is_async_p, since at this point the target is not async
|
||
yet. If it can async, then we know it will become async prior to
|
||
resume. */
|
||
if (!target_can_async_p ())
|
||
{
|
||
/* Async mode is disabled. */
|
||
child_terminal_inferior (self);
|
||
return;
|
||
}
|
||
|
||
child_terminal_inferior (self);
|
||
|
||
/* Calls to target_terminal_*() are meant to be idempotent. */
|
||
if (!async_terminal_is_ours)
|
||
return;
|
||
|
||
delete_file_handler (input_fd);
|
||
async_terminal_is_ours = 0;
|
||
set_sigint_trap ();
|
||
}
|
||
|
||
/* target_terminal_ours implementation.
|
||
|
||
This is a wrapper around child_terminal_ours to add async support (and
|
||
implement the target_terminal_ours vs target_terminal_ours_for_output
|
||
distinction). child_terminal_ours is currently no different than
|
||
child_terminal_ours_for_output.
|
||
We leave target_terminal_ours_for_output alone, leaving it to
|
||
child_terminal_ours_for_output. */
|
||
|
||
static void
|
||
linux_nat_terminal_ours (struct target_ops *self)
|
||
{
|
||
/* GDB should never give the terminal to the inferior if the
|
||
inferior is running in the background (run&, continue&, etc.),
|
||
but claiming it sure should. */
|
||
child_terminal_ours (self);
|
||
|
||
if (async_terminal_is_ours)
|
||
return;
|
||
|
||
clear_sigint_trap ();
|
||
add_file_handler (input_fd, stdin_event_handler, 0);
|
||
async_terminal_is_ours = 1;
|
||
}
|
||
|
||
/* SIGCHLD handler that serves two purposes: In non-stop/async mode,
|
||
so we notice when any child changes state, and notify the
|
||
event-loop; it allows us to use sigsuspend in linux_nat_wait_1
|
||
above to wait for the arrival of a SIGCHLD. */
|
||
|
||
static void
|
||
sigchld_handler (int signo)
|
||
{
|
||
int old_errno = errno;
|
||
|
||
if (debug_linux_nat)
|
||
ui_file_write_async_safe (gdb_stdlog,
|
||
"sigchld\n", sizeof ("sigchld\n") - 1);
|
||
|
||
if (signo == SIGCHLD
|
||
&& linux_nat_event_pipe[0] != -1)
|
||
async_file_mark (); /* Let the event loop know that there are
|
||
events to handle. */
|
||
|
||
errno = old_errno;
|
||
}
|
||
|
||
/* Callback registered with the target events file descriptor. */
|
||
|
||
static void
|
||
handle_target_event (int error, gdb_client_data client_data)
|
||
{
|
||
inferior_event_handler (INF_REG_EVENT, NULL);
|
||
}
|
||
|
||
/* Create/destroy the target events pipe. Returns previous state. */
|
||
|
||
static int
|
||
linux_async_pipe (int enable)
|
||
{
|
||
int previous = linux_is_async_p ();
|
||
|
||
if (previous != enable)
|
||
{
|
||
sigset_t prev_mask;
|
||
|
||
/* Block child signals while we create/destroy the pipe, as
|
||
their handler writes to it. */
|
||
block_child_signals (&prev_mask);
|
||
|
||
if (enable)
|
||
{
|
||
if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
|
||
internal_error (__FILE__, __LINE__,
|
||
"creating event pipe failed.");
|
||
|
||
fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
|
||
fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
|
||
}
|
||
else
|
||
{
|
||
close (linux_nat_event_pipe[0]);
|
||
close (linux_nat_event_pipe[1]);
|
||
linux_nat_event_pipe[0] = -1;
|
||
linux_nat_event_pipe[1] = -1;
|
||
}
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
}
|
||
|
||
return previous;
|
||
}
|
||
|
||
/* target_async implementation. */
|
||
|
||
static void
|
||
linux_nat_async (struct target_ops *ops, int enable)
|
||
{
|
||
if (enable)
|
||
{
|
||
if (!linux_async_pipe (1))
|
||
{
|
||
add_file_handler (linux_nat_event_pipe[0],
|
||
handle_target_event, NULL);
|
||
/* There may be pending events to handle. Tell the event loop
|
||
to poll them. */
|
||
async_file_mark ();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
delete_file_handler (linux_nat_event_pipe[0]);
|
||
linux_async_pipe (0);
|
||
}
|
||
return;
|
||
}
|
||
|
||
/* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
|
||
event came out. */
|
||
|
||
static int
|
||
linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
|
||
{
|
||
if (!lwp->stopped)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNSL: running -> suspending %s\n",
|
||
target_pid_to_str (lwp->ptid));
|
||
|
||
|
||
if (lwp->last_resume_kind == resume_stop)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"linux-nat: already stopping LWP %ld at "
|
||
"GDB's request\n",
|
||
ptid_get_lwp (lwp->ptid));
|
||
return 0;
|
||
}
|
||
|
||
stop_callback (lwp, NULL);
|
||
lwp->last_resume_kind = resume_stop;
|
||
}
|
||
else
|
||
{
|
||
/* Already known to be stopped; do nothing. */
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
if (find_thread_ptid (lwp->ptid)->stop_requested)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNSL: already stopped/stop_requested %s\n",
|
||
target_pid_to_str (lwp->ptid));
|
||
else
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNSL: already stopped/no "
|
||
"stop_requested yet %s\n",
|
||
target_pid_to_str (lwp->ptid));
|
||
}
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
linux_nat_stop (struct target_ops *self, ptid_t ptid)
|
||
{
|
||
if (non_stop)
|
||
iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
|
||
else
|
||
linux_ops->to_stop (linux_ops, ptid);
|
||
}
|
||
|
||
static void
|
||
linux_nat_close (struct target_ops *self)
|
||
{
|
||
/* Unregister from the event loop. */
|
||
if (linux_nat_is_async_p (self))
|
||
linux_nat_async (self, 0);
|
||
|
||
if (linux_ops->to_close)
|
||
linux_ops->to_close (linux_ops);
|
||
|
||
super_close (self);
|
||
}
|
||
|
||
/* When requests are passed down from the linux-nat layer to the
|
||
single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
|
||
used. The address space pointer is stored in the inferior object,
|
||
but the common code that is passed such ptid can't tell whether
|
||
lwpid is a "main" process id or not (it assumes so). We reverse
|
||
look up the "main" process id from the lwp here. */
|
||
|
||
static struct address_space *
|
||
linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
|
||
{
|
||
struct lwp_info *lwp;
|
||
struct inferior *inf;
|
||
int pid;
|
||
|
||
if (ptid_get_lwp (ptid) == 0)
|
||
{
|
||
/* An (lwpid,0,0) ptid. Look up the lwp object to get at the
|
||
tgid. */
|
||
lwp = find_lwp_pid (ptid);
|
||
pid = ptid_get_pid (lwp->ptid);
|
||
}
|
||
else
|
||
{
|
||
/* A (pid,lwpid,0) ptid. */
|
||
pid = ptid_get_pid (ptid);
|
||
}
|
||
|
||
inf = find_inferior_pid (pid);
|
||
gdb_assert (inf != NULL);
|
||
return inf->aspace;
|
||
}
|
||
|
||
/* Return the cached value of the processor core for thread PTID. */
|
||
|
||
static int
|
||
linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
|
||
{
|
||
struct lwp_info *info = find_lwp_pid (ptid);
|
||
|
||
if (info)
|
||
return info->core;
|
||
return -1;
|
||
}
|
||
|
||
/* Implementation of to_filesystem_is_local. */
|
||
|
||
static int
|
||
linux_nat_filesystem_is_local (struct target_ops *ops)
|
||
{
|
||
struct inferior *inf = current_inferior ();
|
||
|
||
if (inf->fake_pid_p || inf->pid == 0)
|
||
return 1;
|
||
|
||
return linux_ns_same (inf->pid, LINUX_NS_MNT);
|
||
}
|
||
|
||
/* Convert the INF argument passed to a to_fileio_* method
|
||
to a process ID suitable for passing to its corresponding
|
||
linux_mntns_* function. If INF is non-NULL then the
|
||
caller is requesting the filesystem seen by INF. If INF
|
||
is NULL then the caller is requesting the filesystem seen
|
||
by the GDB. We fall back to GDB's filesystem in the case
|
||
that INF is non-NULL but its PID is unknown. */
|
||
|
||
static pid_t
|
||
linux_nat_fileio_pid_of (struct inferior *inf)
|
||
{
|
||
if (inf == NULL || inf->fake_pid_p || inf->pid == 0)
|
||
return getpid ();
|
||
else
|
||
return inf->pid;
|
||
}
|
||
|
||
/* Implementation of to_fileio_open. */
|
||
|
||
static int
|
||
linux_nat_fileio_open (struct target_ops *self,
|
||
struct inferior *inf, const char *filename,
|
||
int flags, int mode, int *target_errno)
|
||
{
|
||
int nat_flags;
|
||
mode_t nat_mode;
|
||
int fd;
|
||
|
||
if (fileio_to_host_openflags (flags, &nat_flags) == -1
|
||
|| fileio_to_host_mode (mode, &nat_mode) == -1)
|
||
{
|
||
*target_errno = FILEIO_EINVAL;
|
||
return -1;
|
||
}
|
||
|
||
fd = linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf),
|
||
filename, nat_flags, nat_mode);
|
||
if (fd == -1)
|
||
*target_errno = host_to_fileio_error (errno);
|
||
|
||
return fd;
|
||
}
|
||
|
||
/* Implementation of to_fileio_readlink. */
|
||
|
||
static char *
|
||
linux_nat_fileio_readlink (struct target_ops *self,
|
||
struct inferior *inf, const char *filename,
|
||
int *target_errno)
|
||
{
|
||
char buf[PATH_MAX];
|
||
int len;
|
||
char *ret;
|
||
|
||
len = linux_mntns_readlink (linux_nat_fileio_pid_of (inf),
|
||
filename, buf, sizeof (buf));
|
||
if (len < 0)
|
||
{
|
||
*target_errno = host_to_fileio_error (errno);
|
||
return NULL;
|
||
}
|
||
|
||
ret = xmalloc (len + 1);
|
||
memcpy (ret, buf, len);
|
||
ret[len] = '\0';
|
||
return ret;
|
||
}
|
||
|
||
/* Implementation of to_fileio_unlink. */
|
||
|
||
static int
|
||
linux_nat_fileio_unlink (struct target_ops *self,
|
||
struct inferior *inf, const char *filename,
|
||
int *target_errno)
|
||
{
|
||
int ret;
|
||
|
||
ret = linux_mntns_unlink (linux_nat_fileio_pid_of (inf),
|
||
filename);
|
||
if (ret == -1)
|
||
*target_errno = host_to_fileio_error (errno);
|
||
|
||
return ret;
|
||
}
|
||
|
||
void
|
||
linux_nat_add_target (struct target_ops *t)
|
||
{
|
||
/* Save the provided single-threaded target. We save this in a separate
|
||
variable because another target we've inherited from (e.g. inf-ptrace)
|
||
may have saved a pointer to T; we want to use it for the final
|
||
process stratum target. */
|
||
linux_ops_saved = *t;
|
||
linux_ops = &linux_ops_saved;
|
||
|
||
/* Override some methods for multithreading. */
|
||
t->to_create_inferior = linux_nat_create_inferior;
|
||
t->to_attach = linux_nat_attach;
|
||
t->to_detach = linux_nat_detach;
|
||
t->to_resume = linux_nat_resume;
|
||
t->to_wait = linux_nat_wait;
|
||
t->to_pass_signals = linux_nat_pass_signals;
|
||
t->to_xfer_partial = linux_nat_xfer_partial;
|
||
t->to_kill = linux_nat_kill;
|
||
t->to_mourn_inferior = linux_nat_mourn_inferior;
|
||
t->to_thread_alive = linux_nat_thread_alive;
|
||
t->to_update_thread_list = linux_nat_update_thread_list;
|
||
t->to_pid_to_str = linux_nat_pid_to_str;
|
||
t->to_thread_name = linux_nat_thread_name;
|
||
t->to_has_thread_control = tc_schedlock;
|
||
t->to_thread_address_space = linux_nat_thread_address_space;
|
||
t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
|
||
t->to_stopped_data_address = linux_nat_stopped_data_address;
|
||
t->to_stopped_by_sw_breakpoint = linux_nat_stopped_by_sw_breakpoint;
|
||
t->to_supports_stopped_by_sw_breakpoint = linux_nat_supports_stopped_by_sw_breakpoint;
|
||
t->to_stopped_by_hw_breakpoint = linux_nat_stopped_by_hw_breakpoint;
|
||
t->to_supports_stopped_by_hw_breakpoint = linux_nat_supports_stopped_by_hw_breakpoint;
|
||
|
||
t->to_can_async_p = linux_nat_can_async_p;
|
||
t->to_is_async_p = linux_nat_is_async_p;
|
||
t->to_supports_non_stop = linux_nat_supports_non_stop;
|
||
t->to_async = linux_nat_async;
|
||
t->to_terminal_inferior = linux_nat_terminal_inferior;
|
||
t->to_terminal_ours = linux_nat_terminal_ours;
|
||
|
||
super_close = t->to_close;
|
||
t->to_close = linux_nat_close;
|
||
|
||
/* Methods for non-stop support. */
|
||
t->to_stop = linux_nat_stop;
|
||
|
||
t->to_supports_multi_process = linux_nat_supports_multi_process;
|
||
|
||
t->to_supports_disable_randomization
|
||
= linux_nat_supports_disable_randomization;
|
||
|
||
t->to_core_of_thread = linux_nat_core_of_thread;
|
||
|
||
t->to_filesystem_is_local = linux_nat_filesystem_is_local;
|
||
t->to_fileio_open = linux_nat_fileio_open;
|
||
t->to_fileio_readlink = linux_nat_fileio_readlink;
|
||
t->to_fileio_unlink = linux_nat_fileio_unlink;
|
||
|
||
/* We don't change the stratum; this target will sit at
|
||
process_stratum and thread_db will set at thread_stratum. This
|
||
is a little strange, since this is a multi-threaded-capable
|
||
target, but we want to be on the stack below thread_db, and we
|
||
also want to be used for single-threaded processes. */
|
||
|
||
add_target (t);
|
||
}
|
||
|
||
/* Register a method to call whenever a new thread is attached. */
|
||
void
|
||
linux_nat_set_new_thread (struct target_ops *t,
|
||
void (*new_thread) (struct lwp_info *))
|
||
{
|
||
/* Save the pointer. We only support a single registered instance
|
||
of the GNU/Linux native target, so we do not need to map this to
|
||
T. */
|
||
linux_nat_new_thread = new_thread;
|
||
}
|
||
|
||
/* See declaration in linux-nat.h. */
|
||
|
||
void
|
||
linux_nat_set_new_fork (struct target_ops *t,
|
||
linux_nat_new_fork_ftype *new_fork)
|
||
{
|
||
/* Save the pointer. */
|
||
linux_nat_new_fork = new_fork;
|
||
}
|
||
|
||
/* See declaration in linux-nat.h. */
|
||
|
||
void
|
||
linux_nat_set_forget_process (struct target_ops *t,
|
||
linux_nat_forget_process_ftype *fn)
|
||
{
|
||
/* Save the pointer. */
|
||
linux_nat_forget_process_hook = fn;
|
||
}
|
||
|
||
/* See declaration in linux-nat.h. */
|
||
|
||
void
|
||
linux_nat_forget_process (pid_t pid)
|
||
{
|
||
if (linux_nat_forget_process_hook != NULL)
|
||
linux_nat_forget_process_hook (pid);
|
||
}
|
||
|
||
/* Register a method that converts a siginfo object between the layout
|
||
that ptrace returns, and the layout in the architecture of the
|
||
inferior. */
|
||
void
|
||
linux_nat_set_siginfo_fixup (struct target_ops *t,
|
||
int (*siginfo_fixup) (siginfo_t *,
|
||
gdb_byte *,
|
||
int))
|
||
{
|
||
/* Save the pointer. */
|
||
linux_nat_siginfo_fixup = siginfo_fixup;
|
||
}
|
||
|
||
/* Register a method to call prior to resuming a thread. */
|
||
|
||
void
|
||
linux_nat_set_prepare_to_resume (struct target_ops *t,
|
||
void (*prepare_to_resume) (struct lwp_info *))
|
||
{
|
||
/* Save the pointer. */
|
||
linux_nat_prepare_to_resume = prepare_to_resume;
|
||
}
|
||
|
||
/* See linux-nat.h. */
|
||
|
||
int
|
||
linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
|
||
{
|
||
int pid;
|
||
|
||
pid = ptid_get_lwp (ptid);
|
||
if (pid == 0)
|
||
pid = ptid_get_pid (ptid);
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
|
||
if (errno != 0)
|
||
{
|
||
memset (siginfo, 0, sizeof (*siginfo));
|
||
return 0;
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
ptid_t
|
||
current_lwp_ptid (void)
|
||
{
|
||
gdb_assert (ptid_lwp_p (inferior_ptid));
|
||
return inferior_ptid;
|
||
}
|
||
|
||
/* Provide a prototype to silence -Wmissing-prototypes. */
|
||
extern initialize_file_ftype _initialize_linux_nat;
|
||
|
||
void
|
||
_initialize_linux_nat (void)
|
||
{
|
||
add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
|
||
&debug_linux_nat, _("\
|
||
Set debugging of GNU/Linux lwp module."), _("\
|
||
Show debugging of GNU/Linux lwp module."), _("\
|
||
Enables printf debugging output."),
|
||
NULL,
|
||
show_debug_linux_nat,
|
||
&setdebuglist, &showdebuglist);
|
||
|
||
add_setshow_boolean_cmd ("linux-namespaces", class_maintenance,
|
||
&debug_linux_namespaces, _("\
|
||
Set debugging of GNU/Linux namespaces module."), _("\
|
||
Show debugging of GNU/Linux namespaces module."), _("\
|
||
Enables printf debugging output."),
|
||
NULL,
|
||
NULL,
|
||
&setdebuglist, &showdebuglist);
|
||
|
||
/* Save this mask as the default. */
|
||
sigprocmask (SIG_SETMASK, NULL, &normal_mask);
|
||
|
||
/* Install a SIGCHLD handler. */
|
||
sigchld_action.sa_handler = sigchld_handler;
|
||
sigemptyset (&sigchld_action.sa_mask);
|
||
sigchld_action.sa_flags = SA_RESTART;
|
||
|
||
/* Make it the default. */
|
||
sigaction (SIGCHLD, &sigchld_action, NULL);
|
||
|
||
/* Make sure we don't block SIGCHLD during a sigsuspend. */
|
||
sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
|
||
sigdelset (&suspend_mask, SIGCHLD);
|
||
|
||
sigemptyset (&blocked_mask);
|
||
}
|
||
|
||
|
||
/* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
|
||
the GNU/Linux Threads library and therefore doesn't really belong
|
||
here. */
|
||
|
||
/* Read variable NAME in the target and return its value if found.
|
||
Otherwise return zero. It is assumed that the type of the variable
|
||
is `int'. */
|
||
|
||
static int
|
||
get_signo (const char *name)
|
||
{
|
||
struct bound_minimal_symbol ms;
|
||
int signo;
|
||
|
||
ms = lookup_minimal_symbol (name, NULL, NULL);
|
||
if (ms.minsym == NULL)
|
||
return 0;
|
||
|
||
if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
|
||
sizeof (signo)) != 0)
|
||
return 0;
|
||
|
||
return signo;
|
||
}
|
||
|
||
/* Return the set of signals used by the threads library in *SET. */
|
||
|
||
void
|
||
lin_thread_get_thread_signals (sigset_t *set)
|
||
{
|
||
struct sigaction action;
|
||
int restart, cancel;
|
||
|
||
sigemptyset (&blocked_mask);
|
||
sigemptyset (set);
|
||
|
||
restart = get_signo ("__pthread_sig_restart");
|
||
cancel = get_signo ("__pthread_sig_cancel");
|
||
|
||
/* LinuxThreads normally uses the first two RT signals, but in some legacy
|
||
cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
|
||
not provide any way for the debugger to query the signal numbers -
|
||
fortunately they don't change! */
|
||
|
||
if (restart == 0)
|
||
restart = __SIGRTMIN;
|
||
|
||
if (cancel == 0)
|
||
cancel = __SIGRTMIN + 1;
|
||
|
||
sigaddset (set, restart);
|
||
sigaddset (set, cancel);
|
||
|
||
/* The GNU/Linux Threads library makes terminating threads send a
|
||
special "cancel" signal instead of SIGCHLD. Make sure we catch
|
||
those (to prevent them from terminating GDB itself, which is
|
||
likely to be their default action) and treat them the same way as
|
||
SIGCHLD. */
|
||
|
||
action.sa_handler = sigchld_handler;
|
||
sigemptyset (&action.sa_mask);
|
||
action.sa_flags = SA_RESTART;
|
||
sigaction (cancel, &action, NULL);
|
||
|
||
/* We block the "cancel" signal throughout this code ... */
|
||
sigaddset (&blocked_mask, cancel);
|
||
sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
|
||
|
||
/* ... except during a sigsuspend. */
|
||
sigdelset (&suspend_mask, cancel);
|
||
}
|