6a3753b34b
All callers of target_async pass it the same callback (inferior_event_handler). Since both common code and target backends need to be able to put the target in and out of target async mode at any given time, there's really no way that a different callback could be passed. This commit simplifies things, and removes the indirection altogether. Bonus: with this, gdb's target_async method ends up with the same signature as gdbserver's. Tested on x86_64 Fedora 20, native and gdbserver. gdb/ChangeLog: 2015-03-25 Pedro Alves <palves@redhat.com> * target.h <to_async>: Replace 'callback' and 'context' parameters with boolean 'enable' parameter. (target_async): Replace CALLBACK and CONTEXT parameters with boolean ENABLE parameter. * inf-loop.c (inferior_event_handler): Adjust. * linux-nat.c (linux_nat_attach, linux_nat_resume) (linux_nat_resume): Adjust. (async_client_callback, async_client_context): Delete. (handle_target_event): Call inferior_event_handler directly. (linux_nat_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. Remove references to async_client_callback and async_client_context. (linux_nat_close): Adjust. * record-btrace.c (record_btrace_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. (record_btrace_resume): Adjust. * record-full.c (record_full_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. (record_full_resume, record_full_core_resume): Adjust. * remote.c (struct remote_state) <async_client_callback, async_client_context>: Delete fields. (remote_start_remote, extended_remote_attach_1, remote_resume) (extended_remote_create_inferior): Adjust. (remote_async_serial_handler): Call inferior_event_handler directly. (remote_async): Replace 'callback' and 'context' parameters with boolean 'enable' parameter. Adjust. * top.c (gdb_readline_wrapper_cleanup, gdb_readline_wrapper): Adjust. * target-delegates.c: Regenerate.
5100 lines
142 KiB
C
5100 lines
142 KiB
C
/* GNU/Linux native-dependent code common to multiple platforms.
|
||
|
||
Copyright (C) 2001-2015 Free Software Foundation, Inc.
|
||
|
||
This file is part of GDB.
|
||
|
||
This program is free software; you can redistribute it and/or modify
|
||
it under the terms of the GNU General Public License as published by
|
||
the Free Software Foundation; either version 3 of the License, or
|
||
(at your option) any later version.
|
||
|
||
This program is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
GNU General Public License for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
||
|
||
#include "defs.h"
|
||
#include "inferior.h"
|
||
#include "infrun.h"
|
||
#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>
|
||
#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"
|
||
#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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||
|
||
#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.
|
||
|
||
Waiting for events in sync mode
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===============================
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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.
|
||
|
||
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
|
||
process, if any. Second, we use non-blocking waitpid with the __WCLONED
|
||
flag to check for events in cloned processes. If nothing is found, we use
|
||
sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
|
||
happened to a child process -- and SIGCHLD will be delivered both for events
|
||
in main debugged process and in cloned processes. As soon as we know there's
|
||
an event, we get back to calling nonblocking waitpid with and without
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__WCLONED.
|
||
|
||
Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
|
||
so that we don't miss a signal. If SIGCHLD arrives in between, when it's
|
||
blocked, the signal becomes pending and sigsuspend immediately
|
||
notices it and returns.
|
||
|
||
Waiting for events in async mode
|
||
================================
|
||
|
||
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
|
||
event loop whenever there's an unprocessed event from the target. We
|
||
detect asynchronous target events by handling SIGCHLD signals. To
|
||
notify the event loop about target events, the self-pipe trick is used
|
||
--- a pipe is registered as waitable event source in the event loop,
|
||
the event loop select/poll's on the read end of this pipe (as well on
|
||
other event sources, e.g., stdin), and the SIGCHLD handler writes a
|
||
byte to this pipe. This is more portable than relying on
|
||
pselect/ppoll, since on kernels that lack those syscalls, libc
|
||
emulates them with select/poll+sigprocmask, and that is racy
|
||
(a.k.a. plain broken).
|
||
|
||
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.
|
||
This is mostly harmless, but it will waste time and is better avoided.
|
||
|
||
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
|
||
process things as in sync mode, except that the we never block in
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sigsuspend.
|
||
|
||
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
|
||
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.
|
||
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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||
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||
Use of signals
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||
==============
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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.
|
||
|
||
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).
|
||
|
||
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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||
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||
#ifndef O_LARGEFILE
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#define O_LARGEFILE 0
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||
#endif
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||
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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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||
{
|
||
int pid;
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||
int status;
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struct simple_pid_list *next;
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||
};
|
||
struct simple_pid_list *stopped_pids;
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|
||
/* Async mode support. */
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||
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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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||
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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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||
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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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||
int ret;
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||
|
||
/* It doesn't really matter what the pipe contains, as long we end
|
||
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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|
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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);
|
||
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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|
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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;
|
||
|
||
|
||
/* LWP accessors. */
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
ptid_t
|
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ptid_of_lwp (struct lwp_info *lwp)
|
||
{
|
||
return lwp->ptid;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
void
|
||
lwp_set_arch_private_info (struct lwp_info *lwp,
|
||
struct arch_lwp_info *info)
|
||
{
|
||
lwp->arch_private = info;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
struct arch_lwp_info *
|
||
lwp_arch_private_info (struct lwp_info *lwp)
|
||
{
|
||
return lwp->arch_private;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
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||
|
||
int
|
||
lwp_is_stopped (struct lwp_info *lwp)
|
||
{
|
||
return lwp->stopped;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
enum target_stop_reason
|
||
lwp_stop_reason (struct lwp_info *lwp)
|
||
{
|
||
return lwp->stop_reason;
|
||
}
|
||
|
||
|
||
/* Trivial list manipulation functions to keep track of a list of
|
||
new stopped processes. */
|
||
static void
|
||
add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
|
||
{
|
||
struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
|
||
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||
new_pid->pid = pid;
|
||
new_pid->status = status;
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||
new_pid->next = *listp;
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||
*listp = new_pid;
|
||
}
|
||
|
||
static int
|
||
in_pid_list_p (struct simple_pid_list *list, int pid)
|
||
{
|
||
struct simple_pid_list *p;
|
||
|
||
for (p = list; p != NULL; p = p->next)
|
||
if (p->pid == pid)
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||
return 1;
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||
return 0;
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||
}
|
||
|
||
static int
|
||
pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
|
||
{
|
||
struct simple_pid_list **p;
|
||
|
||
for (p = listp; *p != NULL; p = &(*p)->next)
|
||
if ((*p)->pid == pid)
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||
{
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||
struct simple_pid_list *next = (*p)->next;
|
||
|
||
*statusp = (*p)->status;
|
||
xfree (*p);
|
||
*p = next;
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Initialize ptrace warnings and check for supported ptrace
|
||
features given PID.
|
||
|
||
ATTACHED should be nonzero iff we attached to the inferior. */
|
||
|
||
static void
|
||
linux_init_ptrace (pid_t pid, int attached)
|
||
{
|
||
linux_enable_event_reporting (pid, attached);
|
||
linux_ptrace_init_warnings ();
|
||
}
|
||
|
||
static void
|
||
linux_child_post_attach (struct target_ops *self, int pid)
|
||
{
|
||
linux_init_ptrace (pid, 1);
|
||
}
|
||
|
||
static void
|
||
linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
|
||
{
|
||
linux_init_ptrace (ptid_get_pid (ptid), 0);
|
||
}
|
||
|
||
/* Return the number of known LWPs in the tgid given by PID. */
|
||
|
||
static int
|
||
num_lwps (int pid)
|
||
{
|
||
int count = 0;
|
||
struct lwp_info *lp;
|
||
|
||
for (lp = lwp_list; lp; lp = lp->next)
|
||
if (ptid_get_pid (lp->ptid) == pid)
|
||
count++;
|
||
|
||
return count;
|
||
}
|
||
|
||
/* Call delete_lwp with prototype compatible for make_cleanup. */
|
||
|
||
static void
|
||
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;
|
||
|
||
has_vforked = (inferior_thread ()->pending_follow.kind
|
||
== TARGET_WAITKIND_VFORKED);
|
||
parent_ptid = inferior_ptid;
|
||
child_ptid = inferior_thread ()->pending_follow.value.related_pid;
|
||
parent_pid = ptid_get_lwp (parent_ptid);
|
||
child_pid = ptid_get_lwp (child_ptid);
|
||
|
||
/* 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;
|
||
child_lp->last_resume_kind = resume_stop;
|
||
|
||
/* Detach new forked process? */
|
||
if (detach_fork)
|
||
{
|
||
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);
|
||
}
|
||
|
||
if (!stopping)
|
||
{
|
||
set_running (new_lp->ptid, 1);
|
||
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));
|
||
|
||
linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
|
||
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));
|
||
|
||
linux_enable_event_reporting (ptid_get_lwp (lp->ptid), inf->attach_flag);
|
||
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);
|
||
}
|
||
|
||
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)
|
||
{
|
||
static char buf[PATH_MAX];
|
||
char name[PATH_MAX];
|
||
|
||
xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
|
||
memset (buf, 0, PATH_MAX);
|
||
if (readlink (name, buf, PATH_MAX - 1) <= 0)
|
||
strcpy (buf, name);
|
||
|
||
return buf;
|
||
}
|
||
|
||
/* 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;
|
||
}
|
||
|
||
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_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;
|
||
|
||
/* 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);
|
||
|
||
/* 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);
|
||
|
||
/* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
|
||
support read-only process state. */
|
||
linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
|
||
| PTRACE_O_TRACEVFORKDONE
|
||
| PTRACE_O_TRACEVFORK
|
||
| PTRACE_O_TRACEFORK
|
||
| PTRACE_O_TRACEEXEC);
|
||
}
|
||
|
||
|
||
/* 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);
|
||
}
|