1791 lines
51 KiB
C
1791 lines
51 KiB
C
/* libthread_db assisted debugging support, generic parts.
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Copyright (C) 1999-2018 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include <dlfcn.h>
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#include "gdb_proc_service.h"
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#include "nat/gdb_thread_db.h"
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#include "gdb_vecs.h"
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#include "bfd.h"
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#include "command.h"
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#include "gdbcmd.h"
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#include "gdbthread.h"
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#include "inferior.h"
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#include "infrun.h"
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#include "symfile.h"
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#include "objfiles.h"
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#include "target.h"
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#include "regcache.h"
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#include "solib.h"
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#include "solib-svr4.h"
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#include "gdbcore.h"
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#include "observer.h"
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#include "linux-nat.h"
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#include "nat/linux-procfs.h"
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#include "nat/linux-ptrace.h"
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#include "nat/linux-osdata.h"
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#include "auto-load.h"
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#include "cli/cli-utils.h"
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#include <signal.h>
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#include <ctype.h>
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#include "nat/linux-namespaces.h"
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#include <algorithm>
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/* GNU/Linux libthread_db support.
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libthread_db is a library, provided along with libpthread.so, which
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exposes the internals of the thread library to a debugger. It
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allows GDB to find existing threads, new threads as they are
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created, thread IDs (usually, the result of pthread_self), and
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thread-local variables.
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The libthread_db interface originates on Solaris, where it is both
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more powerful and more complicated. This implementation only works
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for NPTL, the glibc threading library. It assumes that each thread
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is permanently assigned to a single light-weight process (LWP). At
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some point it also supported the older LinuxThreads library, but it
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no longer does.
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libthread_db-specific information is stored in the "private" field
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of struct thread_info. When the field is NULL we do not yet have
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information about the new thread; this could be temporary (created,
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but the thread library's data structures do not reflect it yet)
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or permanent (created using clone instead of pthread_create).
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Process IDs managed by linux-thread-db.c match those used by
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linux-nat.c: a common PID for all processes, an LWP ID for each
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thread, and no TID. We save the TID in private. Keeping it out
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of the ptid_t prevents thread IDs changing when libpthread is
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loaded or unloaded. */
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static char *libthread_db_search_path;
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/* Set to non-zero if thread_db auto-loading is enabled
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by the "set auto-load libthread-db" command. */
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static int auto_load_thread_db = 1;
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/* "show" command for the auto_load_thread_db configuration variable. */
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static void
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show_auto_load_thread_db (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, _("Auto-loading of inferior specific libthread_db "
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"is %s.\n"),
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value);
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}
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static void
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set_libthread_db_search_path (const char *ignored, int from_tty,
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struct cmd_list_element *c)
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{
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if (*libthread_db_search_path == '\0')
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{
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xfree (libthread_db_search_path);
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libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
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}
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}
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/* If non-zero, print details of libthread_db processing. */
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static unsigned int libthread_db_debug;
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static void
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show_libthread_db_debug (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, _("libthread-db debugging is %s.\n"), value);
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}
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/* If we're running on GNU/Linux, we must explicitly attach to any new
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threads. */
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/* This module's target vector. */
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static struct target_ops thread_db_ops;
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/* Non-zero if we have determined the signals used by the threads
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library. */
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static int thread_signals;
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static sigset_t thread_stop_set;
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static sigset_t thread_print_set;
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struct thread_db_info
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{
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struct thread_db_info *next;
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/* Process id this object refers to. */
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int pid;
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/* Handle from dlopen for libthread_db.so. */
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void *handle;
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/* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
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HANDLE. It may be NULL for system library. */
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char *filename;
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/* Structure that identifies the child process for the
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<proc_service.h> interface. */
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struct ps_prochandle proc_handle;
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/* Connection to the libthread_db library. */
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td_thragent_t *thread_agent;
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/* True if we need to apply the workaround for glibc/BZ5983. When
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we catch a PTRACE_O_TRACEFORK, and go query the child's thread
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list, nptl_db returns the parent's threads in addition to the new
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(single) child thread. If this flag is set, we do extra work to
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be able to ignore such stale entries. */
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int need_stale_parent_threads_check;
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/* Pointers to the libthread_db functions. */
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td_init_ftype *td_init_p;
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td_ta_new_ftype *td_ta_new_p;
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td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p;
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td_ta_thr_iter_ftype *td_ta_thr_iter_p;
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td_thr_get_info_ftype *td_thr_get_info_p;
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td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p;
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td_thr_tlsbase_ftype *td_thr_tlsbase_p;
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};
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/* List of known processes using thread_db, and the required
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bookkeeping. */
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struct thread_db_info *thread_db_list;
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static void thread_db_find_new_threads_1 (ptid_t ptid);
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static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new);
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static void check_thread_signals (void);
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static struct thread_info *record_thread
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(struct thread_db_info *info, struct thread_info *tp,
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ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p);
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/* Add the current inferior to the list of processes using libpthread.
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Return a pointer to the newly allocated object that was added to
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THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
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LIBTHREAD_DB_SO. */
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static struct thread_db_info *
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add_thread_db_info (void *handle)
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{
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struct thread_db_info *info = XCNEW (struct thread_db_info);
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info->pid = ptid_get_pid (inferior_ptid);
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info->handle = handle;
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/* The workaround works by reading from /proc/pid/status, so it is
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disabled for core files. */
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if (target_has_execution)
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info->need_stale_parent_threads_check = 1;
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info->next = thread_db_list;
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thread_db_list = info;
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return info;
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}
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/* Return the thread_db_info object representing the bookkeeping
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related to process PID, if any; NULL otherwise. */
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static struct thread_db_info *
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get_thread_db_info (int pid)
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{
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struct thread_db_info *info;
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for (info = thread_db_list; info; info = info->next)
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if (pid == info->pid)
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return info;
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return NULL;
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}
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/* When PID has exited or has been detached, we no longer want to keep
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track of it as using libpthread. Call this function to discard
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thread_db related info related to PID. Note that this closes
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LIBTHREAD_DB_SO's dlopen'ed handle. */
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static void
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delete_thread_db_info (int pid)
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{
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struct thread_db_info *info, *info_prev;
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info_prev = NULL;
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for (info = thread_db_list; info; info_prev = info, info = info->next)
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if (pid == info->pid)
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break;
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if (info == NULL)
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return;
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if (info->handle != NULL)
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dlclose (info->handle);
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xfree (info->filename);
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if (info_prev)
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info_prev->next = info->next;
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else
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thread_db_list = info->next;
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xfree (info);
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}
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/* Use "struct private_thread_info" to cache thread state. This is
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a substantial optimization. */
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struct thread_db_thread_info : public private_thread_info
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{
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/* Flag set when we see a TD_DEATH event for this thread. */
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bool dying = false;
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/* Cached thread state. */
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td_thrhandle_t th {};
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thread_t tid {};
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};
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static thread_db_thread_info *
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get_thread_db_thread_info (thread_info *thread)
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{
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return static_cast<thread_db_thread_info *> (thread->priv.get ());
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}
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static const char *
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thread_db_err_str (td_err_e err)
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{
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static char buf[64];
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switch (err)
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{
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case TD_OK:
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return "generic 'call succeeded'";
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case TD_ERR:
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return "generic error";
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case TD_NOTHR:
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return "no thread to satisfy query";
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case TD_NOSV:
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return "no sync handle to satisfy query";
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case TD_NOLWP:
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return "no LWP to satisfy query";
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case TD_BADPH:
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return "invalid process handle";
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case TD_BADTH:
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return "invalid thread handle";
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case TD_BADSH:
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return "invalid synchronization handle";
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case TD_BADTA:
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return "invalid thread agent";
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case TD_BADKEY:
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return "invalid key";
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case TD_NOMSG:
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return "no event message for getmsg";
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case TD_NOFPREGS:
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return "FPU register set not available";
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case TD_NOLIBTHREAD:
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return "application not linked with libthread";
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case TD_NOEVENT:
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return "requested event is not supported";
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case TD_NOCAPAB:
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return "capability not available";
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case TD_DBERR:
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return "debugger service failed";
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case TD_NOAPLIC:
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return "operation not applicable to";
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case TD_NOTSD:
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return "no thread-specific data for this thread";
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case TD_MALLOC:
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return "malloc failed";
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case TD_PARTIALREG:
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return "only part of register set was written/read";
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case TD_NOXREGS:
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return "X register set not available for this thread";
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#ifdef THREAD_DB_HAS_TD_NOTALLOC
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case TD_NOTALLOC:
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return "thread has not yet allocated TLS for given module";
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#endif
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#ifdef THREAD_DB_HAS_TD_VERSION
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case TD_VERSION:
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return "versions of libpthread and libthread_db do not match";
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#endif
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#ifdef THREAD_DB_HAS_TD_NOTLS
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case TD_NOTLS:
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return "there is no TLS segment in the given module";
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#endif
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default:
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snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
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return buf;
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}
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}
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/* Fetch the user-level thread id of PTID. */
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static struct thread_info *
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thread_from_lwp (ptid_t ptid)
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{
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td_thrhandle_t th;
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td_thrinfo_t ti;
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td_err_e err;
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struct thread_db_info *info;
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struct thread_info *tp;
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/* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
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th.th_unique = 0;
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/* This ptid comes from linux-nat.c, which should always fill in the
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LWP. */
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gdb_assert (ptid_get_lwp (ptid) != 0);
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info = get_thread_db_info (ptid_get_pid (ptid));
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/* Access an lwp we know is stopped. */
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info->proc_handle.ptid = ptid;
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err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid_get_lwp (ptid),
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&th);
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if (err != TD_OK)
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error (_("Cannot find user-level thread for LWP %ld: %s"),
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ptid_get_lwp (ptid), thread_db_err_str (err));
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err = info->td_thr_get_info_p (&th, &ti);
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if (err != TD_OK)
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error (_("thread_get_info_callback: cannot get thread info: %s"),
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thread_db_err_str (err));
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/* Fill the cache. */
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tp = find_thread_ptid (ptid);
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return record_thread (info, tp, ptid, &th, &ti);
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}
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/* See linux-nat.h. */
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int
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thread_db_notice_clone (ptid_t parent, ptid_t child)
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{
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struct thread_db_info *info;
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info = get_thread_db_info (ptid_get_pid (child));
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if (info == NULL)
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return 0;
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thread_from_lwp (child);
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/* If we do not know about the main thread yet, this would be a good
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time to find it. */
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thread_from_lwp (parent);
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return 1;
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}
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static void *
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verbose_dlsym (void *handle, const char *name)
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{
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void *sym = dlsym (handle, name);
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if (sym == NULL)
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warning (_("Symbol \"%s\" not found in libthread_db: %s"),
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name, dlerror ());
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return sym;
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}
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/* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
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return 1 if this version is lower (and not equal) to
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VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
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static int
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inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min)
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{
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struct bound_minimal_symbol version_msym;
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CORE_ADDR version_addr;
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char *version;
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int err, got, retval = 0;
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version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL);
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if (version_msym.minsym == NULL)
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return 0;
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version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym);
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got = target_read_string (version_addr, &version, 32, &err);
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if (err == 0 && memchr (version, 0, got) == &version[got -1])
|
||
{
|
||
int major, minor;
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||
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retval = (sscanf (version, "%d.%d", &major, &minor) == 2
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&& (major < ver_major_min
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|| (major == ver_major_min && minor < ver_minor_min)));
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||
}
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xfree (version);
|
||
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return retval;
|
||
}
|
||
|
||
/* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
|
||
if appropriate.
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|
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Return 1 if the caller should abort libthread_db initialization. Return 0
|
||
otherwise. */
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||
|
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static int
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thread_db_find_new_threads_silently (ptid_t ptid)
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||
{
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||
|
||
TRY
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||
{
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||
thread_db_find_new_threads_2 (ptid, 1);
|
||
}
|
||
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||
CATCH (except, RETURN_MASK_ERROR)
|
||
{
|
||
if (libthread_db_debug)
|
||
exception_fprintf (gdb_stdlog, except,
|
||
"Warning: thread_db_find_new_threads_silently: ");
|
||
|
||
/* There is a bug fixed between nptl 2.6.1 and 2.7 by
|
||
commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
|
||
where calls to td_thr_get_info fail with TD_ERR for statically linked
|
||
executables if td_thr_get_info is called before glibc has initialized
|
||
itself.
|
||
|
||
If the nptl bug is NOT present in the inferior and still thread_db
|
||
reports an error return 1. It means the inferior has corrupted thread
|
||
list and GDB should fall back only to LWPs.
|
||
|
||
If the nptl bug is present in the inferior return 0 to silently ignore
|
||
such errors, and let gdb enumerate threads again later. In such case
|
||
GDB cannot properly display LWPs if the inferior thread list is
|
||
corrupted. For core files it does not apply, no 'later enumeration'
|
||
is possible. */
|
||
|
||
if (!target_has_execution || !inferior_has_bug ("nptl_version", 2, 7))
|
||
{
|
||
exception_fprintf (gdb_stderr, except,
|
||
_("Warning: couldn't activate thread debugging "
|
||
"using libthread_db: "));
|
||
return 1;
|
||
}
|
||
}
|
||
END_CATCH
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Lookup a library in which given symbol resides.
|
||
Note: this is looking in GDB process, not in the inferior.
|
||
Returns library name, or NULL. */
|
||
|
||
static const char *
|
||
dladdr_to_soname (const void *addr)
|
||
{
|
||
Dl_info info;
|
||
|
||
if (dladdr (addr, &info) != 0)
|
||
return info.dli_fname;
|
||
return NULL;
|
||
}
|
||
|
||
/* Attempt to initialize dlopen()ed libthread_db, described by INFO.
|
||
Return 1 on success.
|
||
Failure could happen if libthread_db does not have symbols we expect,
|
||
or when it refuses to work with the current inferior (e.g. due to
|
||
version mismatch between libthread_db and libpthread). */
|
||
|
||
static int
|
||
try_thread_db_load_1 (struct thread_db_info *info)
|
||
{
|
||
td_err_e err;
|
||
|
||
/* Initialize pointers to the dynamic library functions we will use.
|
||
Essential functions first. */
|
||
|
||
#define TDB_VERBOSE_DLSYM(info, func) \
|
||
info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
|
||
|
||
#define TDB_DLSYM(info, func) \
|
||
info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
|
||
|
||
#define CHK(a) \
|
||
do \
|
||
{ \
|
||
if ((a) == NULL) \
|
||
return 0; \
|
||
} while (0)
|
||
|
||
CHK (TDB_VERBOSE_DLSYM (info, td_init));
|
||
|
||
err = info->td_init_p ();
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Cannot initialize libthread_db: %s"),
|
||
thread_db_err_str (err));
|
||
return 0;
|
||
}
|
||
|
||
CHK (TDB_VERBOSE_DLSYM (info, td_ta_new));
|
||
|
||
/* Initialize the structure that identifies the child process. */
|
||
info->proc_handle.ptid = inferior_ptid;
|
||
|
||
/* Now attempt to open a connection to the thread library. */
|
||
err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
|
||
if (err != TD_OK)
|
||
{
|
||
if (libthread_db_debug)
|
||
fprintf_unfiltered (gdb_stdlog, _("td_ta_new failed: %s\n"),
|
||
thread_db_err_str (err));
|
||
else
|
||
switch (err)
|
||
{
|
||
case TD_NOLIBTHREAD:
|
||
#ifdef THREAD_DB_HAS_TD_VERSION
|
||
case TD_VERSION:
|
||
#endif
|
||
/* The errors above are not unexpected and silently ignored:
|
||
they just mean we haven't found correct version of
|
||
libthread_db yet. */
|
||
break;
|
||
default:
|
||
warning (_("td_ta_new failed: %s"), thread_db_err_str (err));
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* These are essential. */
|
||
CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr));
|
||
CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info));
|
||
|
||
/* These are not essential. */
|
||
TDB_DLSYM (info, td_thr_tls_get_addr);
|
||
TDB_DLSYM (info, td_thr_tlsbase);
|
||
|
||
/* It's best to avoid td_ta_thr_iter if possible. That walks data
|
||
structures in the inferior's address space that may be corrupted,
|
||
or, if the target is running, may change while we walk them. If
|
||
there's execution (and /proc is mounted), then we're already
|
||
attached to all LWPs. Use thread_from_lwp, which uses
|
||
td_ta_map_lwp2thr instead, which does not walk the thread list.
|
||
|
||
td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
|
||
currently on core targets, as it uses ptrace directly. */
|
||
if (target_has_execution
|
||
&& linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid)))
|
||
info->td_ta_thr_iter_p = NULL;
|
||
else
|
||
CHK (TDB_VERBOSE_DLSYM (info, td_ta_thr_iter));
|
||
|
||
#undef TDB_VERBOSE_DLSYM
|
||
#undef TDB_DLSYM
|
||
#undef CHK
|
||
|
||
if (info->td_ta_thr_iter_p == NULL)
|
||
{
|
||
struct lwp_info *lp;
|
||
int pid = ptid_get_pid (inferior_ptid);
|
||
|
||
linux_stop_and_wait_all_lwps ();
|
||
|
||
ALL_LWPS (lp)
|
||
if (ptid_get_pid (lp->ptid) == pid)
|
||
thread_from_lwp (lp->ptid);
|
||
|
||
linux_unstop_all_lwps ();
|
||
}
|
||
else if (thread_db_find_new_threads_silently (inferior_ptid) != 0)
|
||
{
|
||
/* Even if libthread_db initializes, if the thread list is
|
||
corrupted, we'd not manage to list any threads. Better reject this
|
||
thread_db, and fall back to at least listing LWPs. */
|
||
return 0;
|
||
}
|
||
|
||
printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
|
||
|
||
if (*libthread_db_search_path || libthread_db_debug)
|
||
{
|
||
struct ui_file *file;
|
||
const char *library;
|
||
|
||
library = dladdr_to_soname ((const void *) *info->td_ta_new_p);
|
||
if (library == NULL)
|
||
library = LIBTHREAD_DB_SO;
|
||
|
||
/* If we'd print this to gdb_stdout when debug output is
|
||
disabled, still print it to gdb_stdout if debug output is
|
||
enabled. User visible output should not depend on debug
|
||
settings. */
|
||
file = *libthread_db_search_path != '\0' ? gdb_stdout : gdb_stdlog;
|
||
fprintf_unfiltered (file, _("Using host libthread_db library \"%s\".\n"),
|
||
library);
|
||
}
|
||
|
||
/* The thread library was detected. Activate the thread_db target
|
||
if this is the first process using it. */
|
||
if (thread_db_list->next == NULL)
|
||
push_target (&thread_db_ops);
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
|
||
relative, or just LIBTHREAD_DB. */
|
||
|
||
static int
|
||
try_thread_db_load (const char *library, int check_auto_load_safe)
|
||
{
|
||
void *handle;
|
||
struct thread_db_info *info;
|
||
|
||
if (libthread_db_debug)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
_("Trying host libthread_db library: %s.\n"),
|
||
library);
|
||
|
||
if (check_auto_load_safe)
|
||
{
|
||
if (access (library, R_OK) != 0)
|
||
{
|
||
/* Do not print warnings by file_is_auto_load_safe if the library does
|
||
not exist at this place. */
|
||
if (libthread_db_debug)
|
||
fprintf_unfiltered (gdb_stdlog, _("open failed: %s.\n"),
|
||
safe_strerror (errno));
|
||
return 0;
|
||
}
|
||
|
||
if (!file_is_auto_load_safe (library, _("auto-load: Loading libthread-db "
|
||
"library \"%s\" from explicit "
|
||
"directory.\n"),
|
||
library))
|
||
return 0;
|
||
}
|
||
|
||
handle = dlopen (library, RTLD_NOW);
|
||
if (handle == NULL)
|
||
{
|
||
if (libthread_db_debug)
|
||
fprintf_unfiltered (gdb_stdlog, _("dlopen failed: %s.\n"), dlerror ());
|
||
return 0;
|
||
}
|
||
|
||
if (libthread_db_debug && strchr (library, '/') == NULL)
|
||
{
|
||
void *td_init;
|
||
|
||
td_init = dlsym (handle, "td_init");
|
||
if (td_init != NULL)
|
||
{
|
||
const char *const libpath = dladdr_to_soname (td_init);
|
||
|
||
if (libpath != NULL)
|
||
fprintf_unfiltered (gdb_stdlog, _("Host %s resolved to: %s.\n"),
|
||
library, libpath);
|
||
}
|
||
}
|
||
|
||
info = add_thread_db_info (handle);
|
||
|
||
/* Do not save system library name, that one is always trusted. */
|
||
if (strchr (library, '/') != NULL)
|
||
info->filename = gdb_realpath (library).release ();
|
||
|
||
if (try_thread_db_load_1 (info))
|
||
return 1;
|
||
|
||
/* This library "refused" to work on current inferior. */
|
||
delete_thread_db_info (ptid_get_pid (inferior_ptid));
|
||
return 0;
|
||
}
|
||
|
||
/* Subroutine of try_thread_db_load_from_pdir to simplify it.
|
||
Try loading libthread_db in directory(OBJ)/SUBDIR.
|
||
SUBDIR may be NULL. It may also be something like "../lib64".
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_pdir_1 (struct objfile *obj, const char *subdir)
|
||
{
|
||
struct cleanup *cleanup;
|
||
char *path, *cp;
|
||
int result;
|
||
const char *obj_name = objfile_name (obj);
|
||
int alloc_len;
|
||
|
||
if (obj_name[0] != '/')
|
||
{
|
||
warning (_("Expected absolute pathname for libpthread in the"
|
||
" inferior, but got %s."), obj_name);
|
||
return 0;
|
||
}
|
||
|
||
alloc_len = (strlen (obj_name)
|
||
+ (subdir ? strlen (subdir) + 1 : 0)
|
||
+ 1 + strlen (LIBTHREAD_DB_SO) + 1);
|
||
path = (char *) xmalloc (alloc_len);
|
||
cleanup = make_cleanup (xfree, path);
|
||
|
||
strcpy (path, obj_name);
|
||
cp = strrchr (path, '/');
|
||
/* This should at minimum hit the first character. */
|
||
gdb_assert (cp != NULL);
|
||
cp[1] = '\0';
|
||
if (subdir != NULL)
|
||
{
|
||
strcat (cp, subdir);
|
||
strcat (cp, "/");
|
||
}
|
||
strcat (cp, LIBTHREAD_DB_SO);
|
||
|
||
result = try_thread_db_load (path, 1);
|
||
|
||
do_cleanups (cleanup);
|
||
return result;
|
||
}
|
||
|
||
/* Handle $pdir in libthread-db-search-path.
|
||
Look for libthread_db in directory(libpthread)/SUBDIR.
|
||
SUBDIR may be NULL. It may also be something like "../lib64".
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_pdir (const char *subdir)
|
||
{
|
||
struct objfile *obj;
|
||
|
||
if (!auto_load_thread_db)
|
||
return 0;
|
||
|
||
ALL_OBJFILES (obj)
|
||
if (libpthread_name_p (objfile_name (obj)))
|
||
{
|
||
if (try_thread_db_load_from_pdir_1 (obj, subdir))
|
||
return 1;
|
||
|
||
/* We may have found the separate-debug-info version of
|
||
libpthread, and it may live in a directory without a matching
|
||
libthread_db. */
|
||
if (obj->separate_debug_objfile_backlink != NULL)
|
||
return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink,
|
||
subdir);
|
||
|
||
return 0;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Handle $sdir in libthread-db-search-path.
|
||
Look for libthread_db in the system dirs, or wherever a plain
|
||
dlopen(file_without_path) will look.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_sdir (void)
|
||
{
|
||
return try_thread_db_load (LIBTHREAD_DB_SO, 0);
|
||
}
|
||
|
||
/* Try to load libthread_db from directory DIR of length DIR_LEN.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_dir (const char *dir, size_t dir_len)
|
||
{
|
||
struct cleanup *cleanup;
|
||
char *path;
|
||
int result;
|
||
|
||
if (!auto_load_thread_db)
|
||
return 0;
|
||
|
||
path = (char *) xmalloc (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1);
|
||
cleanup = make_cleanup (xfree, path);
|
||
|
||
memcpy (path, dir, dir_len);
|
||
path[dir_len] = '/';
|
||
strcpy (path + dir_len + 1, LIBTHREAD_DB_SO);
|
||
|
||
result = try_thread_db_load (path, 1);
|
||
|
||
do_cleanups (cleanup);
|
||
return result;
|
||
}
|
||
|
||
/* Search libthread_db_search_path for libthread_db which "agrees"
|
||
to work on current inferior.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
thread_db_load_search (void)
|
||
{
|
||
VEC (char_ptr) *dir_vec;
|
||
struct cleanup *cleanups;
|
||
char *this_dir;
|
||
int i, rc = 0;
|
||
|
||
dir_vec = dirnames_to_char_ptr_vec (libthread_db_search_path);
|
||
cleanups = make_cleanup_free_char_ptr_vec (dir_vec);
|
||
|
||
for (i = 0; VEC_iterate (char_ptr, dir_vec, i, this_dir); ++i)
|
||
{
|
||
const int pdir_len = sizeof ("$pdir") - 1;
|
||
size_t this_dir_len;
|
||
|
||
this_dir_len = strlen (this_dir);
|
||
|
||
if (strncmp (this_dir, "$pdir", pdir_len) == 0
|
||
&& (this_dir[pdir_len] == '\0'
|
||
|| this_dir[pdir_len] == '/'))
|
||
{
|
||
char *subdir = NULL;
|
||
struct cleanup *free_subdir_cleanup
|
||
= make_cleanup (null_cleanup, NULL);
|
||
|
||
if (this_dir[pdir_len] == '/')
|
||
{
|
||
subdir = (char *) xmalloc (strlen (this_dir));
|
||
make_cleanup (xfree, subdir);
|
||
strcpy (subdir, this_dir + pdir_len + 1);
|
||
}
|
||
rc = try_thread_db_load_from_pdir (subdir);
|
||
do_cleanups (free_subdir_cleanup);
|
||
if (rc)
|
||
break;
|
||
}
|
||
else if (strcmp (this_dir, "$sdir") == 0)
|
||
{
|
||
if (try_thread_db_load_from_sdir ())
|
||
{
|
||
rc = 1;
|
||
break;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (try_thread_db_load_from_dir (this_dir, this_dir_len))
|
||
{
|
||
rc = 1;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
do_cleanups (cleanups);
|
||
if (libthread_db_debug)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
_("thread_db_load_search returning %d\n"), rc);
|
||
return rc;
|
||
}
|
||
|
||
/* Return non-zero if the inferior has a libpthread. */
|
||
|
||
static int
|
||
has_libpthread (void)
|
||
{
|
||
struct objfile *obj;
|
||
|
||
ALL_OBJFILES (obj)
|
||
if (libpthread_name_p (objfile_name (obj)))
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Attempt to load and initialize libthread_db.
|
||
Return 1 on success. */
|
||
|
||
static int
|
||
thread_db_load (void)
|
||
{
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (ptid_get_pid (inferior_ptid));
|
||
|
||
if (info != NULL)
|
||
return 1;
|
||
|
||
/* Don't attempt to use thread_db on executables not running
|
||
yet. */
|
||
if (!target_has_registers)
|
||
return 0;
|
||
|
||
/* Don't attempt to use thread_db for remote targets. */
|
||
if (!(target_can_run (¤t_target) || core_bfd))
|
||
return 0;
|
||
|
||
if (thread_db_load_search ())
|
||
return 1;
|
||
|
||
/* We couldn't find a libthread_db.
|
||
If the inferior has a libpthread warn the user. */
|
||
if (has_libpthread ())
|
||
{
|
||
warning (_("Unable to find libthread_db matching inferior's thread"
|
||
" library, thread debugging will not be available."));
|
||
return 0;
|
||
}
|
||
|
||
/* Either this executable isn't using libpthread at all, or it is
|
||
statically linked. Since we can't easily distinguish these two cases,
|
||
no warning is issued. */
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
check_thread_signals (void)
|
||
{
|
||
if (!thread_signals)
|
||
{
|
||
sigset_t mask;
|
||
int i;
|
||
|
||
lin_thread_get_thread_signals (&mask);
|
||
sigemptyset (&thread_stop_set);
|
||
sigemptyset (&thread_print_set);
|
||
|
||
for (i = 1; i < NSIG; i++)
|
||
{
|
||
if (sigismember (&mask, i))
|
||
{
|
||
if (signal_stop_update (gdb_signal_from_host (i), 0))
|
||
sigaddset (&thread_stop_set, i);
|
||
if (signal_print_update (gdb_signal_from_host (i), 0))
|
||
sigaddset (&thread_print_set, i);
|
||
thread_signals = 1;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Check whether thread_db is usable. This function is called when
|
||
an inferior is created (or otherwise acquired, e.g. attached to)
|
||
and when new shared libraries are loaded into a running process. */
|
||
|
||
void
|
||
check_for_thread_db (void)
|
||
{
|
||
/* Do nothing if we couldn't load libthread_db.so.1. */
|
||
if (!thread_db_load ())
|
||
return;
|
||
}
|
||
|
||
/* This function is called via the new_objfile observer. */
|
||
|
||
static void
|
||
thread_db_new_objfile (struct objfile *objfile)
|
||
{
|
||
/* This observer must always be called with inferior_ptid set
|
||
correctly. */
|
||
|
||
if (objfile != NULL
|
||
/* libpthread with separate debug info has its debug info file already
|
||
loaded (and notified without successful thread_db initialization)
|
||
the time observer_notify_new_objfile is called for the library itself.
|
||
Static executables have their separate debug info loaded already
|
||
before the inferior has started. */
|
||
&& objfile->separate_debug_objfile_backlink == NULL
|
||
/* Only check for thread_db if we loaded libpthread,
|
||
or if this is the main symbol file.
|
||
We need to check OBJF_MAINLINE to handle the case of debugging
|
||
a statically linked executable AND the symbol file is specified AFTER
|
||
the exec file is loaded (e.g., gdb -c core ; file foo).
|
||
For dynamically linked executables, libpthread can be near the end
|
||
of the list of shared libraries to load, and in an app of several
|
||
thousand shared libraries, this can otherwise be painful. */
|
||
&& ((objfile->flags & OBJF_MAINLINE) != 0
|
||
|| libpthread_name_p (objfile_name (objfile))))
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
static void
|
||
check_pid_namespace_match (void)
|
||
{
|
||
/* Check is only relevant for local targets targets. */
|
||
if (target_can_run (¤t_target))
|
||
{
|
||
/* If the child is in a different PID namespace, its idea of its
|
||
PID will differ from our idea of its PID. When we scan the
|
||
child's thread list, we'll mistakenly think it has no threads
|
||
since the thread PID fields won't match the PID we give to
|
||
libthread_db. */
|
||
if (!linux_ns_same (ptid_get_pid (inferior_ptid), LINUX_NS_PID))
|
||
{
|
||
warning (_ ("Target and debugger are in different PID "
|
||
"namespaces; thread lists and other data are "
|
||
"likely unreliable. "
|
||
"Connect to gdbserver inside the container."));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* This function is called via the inferior_created observer.
|
||
This handles the case of debugging statically linked executables. */
|
||
|
||
static void
|
||
thread_db_inferior_created (struct target_ops *target, int from_tty)
|
||
{
|
||
check_pid_namespace_match ();
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
/* Update the thread's state (what's displayed in "info threads"),
|
||
from libthread_db thread state information. */
|
||
|
||
static void
|
||
update_thread_state (thread_db_thread_info *priv,
|
||
const td_thrinfo_t *ti_p)
|
||
{
|
||
priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN
|
||
|| ti_p->ti_state == TD_THR_ZOMBIE);
|
||
}
|
||
|
||
/* Record a new thread in GDB's thread list. Creates the thread's
|
||
private info. If TP is NULL or TP is marked as having exited,
|
||
creates a new thread. Otherwise, uses TP. */
|
||
|
||
static struct thread_info *
|
||
record_thread (struct thread_db_info *info,
|
||
struct thread_info *tp,
|
||
ptid_t ptid, const td_thrhandle_t *th_p,
|
||
const td_thrinfo_t *ti_p)
|
||
{
|
||
/* A thread ID of zero may mean the thread library has not
|
||
initialized yet. Leave private == NULL until the thread library
|
||
has initialized. */
|
||
if (ti_p->ti_tid == 0)
|
||
return tp;
|
||
|
||
/* Construct the thread's private data. */
|
||
thread_db_thread_info *priv = new thread_db_thread_info;
|
||
|
||
priv->th = *th_p;
|
||
priv->tid = ti_p->ti_tid;
|
||
update_thread_state (priv, ti_p);
|
||
|
||
/* Add the thread to GDB's thread list. If we already know about a
|
||
thread with this PTID, but it's marked exited, then the kernel
|
||
reused the tid of an old thread. */
|
||
if (tp == NULL || tp->state == THREAD_EXITED)
|
||
tp = add_thread_with_info (ptid, priv);
|
||
else
|
||
tp->priv.reset (priv);
|
||
|
||
if (target_has_execution)
|
||
check_thread_signals ();
|
||
|
||
return tp;
|
||
}
|
||
|
||
static void
|
||
thread_db_detach (struct target_ops *ops, const char *args, int from_tty)
|
||
{
|
||
struct target_ops *target_beneath = find_target_beneath (ops);
|
||
|
||
delete_thread_db_info (ptid_get_pid (inferior_ptid));
|
||
|
||
target_beneath->to_detach (target_beneath, args, from_tty);
|
||
|
||
/* NOTE: From this point on, inferior_ptid is null_ptid. */
|
||
|
||
/* If there are no more processes using libpthread, detach the
|
||
thread_db target ops. */
|
||
if (!thread_db_list)
|
||
unpush_target (&thread_db_ops);
|
||
}
|
||
|
||
static ptid_t
|
||
thread_db_wait (struct target_ops *ops,
|
||
ptid_t ptid, struct target_waitstatus *ourstatus,
|
||
int options)
|
||
{
|
||
struct thread_db_info *info;
|
||
struct target_ops *beneath = find_target_beneath (ops);
|
||
|
||
ptid = beneath->to_wait (beneath, ptid, ourstatus, options);
|
||
|
||
switch (ourstatus->kind)
|
||
{
|
||
case TARGET_WAITKIND_IGNORE:
|
||
case TARGET_WAITKIND_EXITED:
|
||
case TARGET_WAITKIND_THREAD_EXITED:
|
||
case TARGET_WAITKIND_SIGNALLED:
|
||
return ptid;
|
||
}
|
||
|
||
info = get_thread_db_info (ptid_get_pid (ptid));
|
||
|
||
/* If this process isn't using thread_db, we're done. */
|
||
if (info == NULL)
|
||
return ptid;
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXECD)
|
||
{
|
||
/* New image, it may or may not end up using thread_db. Assume
|
||
not unless we find otherwise. */
|
||
delete_thread_db_info (ptid_get_pid (ptid));
|
||
if (!thread_db_list)
|
||
unpush_target (&thread_db_ops);
|
||
|
||
return ptid;
|
||
}
|
||
|
||
/* Fill in the thread's user-level thread id and status. */
|
||
thread_from_lwp (ptid);
|
||
|
||
return ptid;
|
||
}
|
||
|
||
static void
|
||
thread_db_mourn_inferior (struct target_ops *ops)
|
||
{
|
||
struct target_ops *target_beneath = find_target_beneath (ops);
|
||
|
||
delete_thread_db_info (ptid_get_pid (inferior_ptid));
|
||
|
||
target_beneath->to_mourn_inferior (target_beneath);
|
||
|
||
/* Detach thread_db target ops. */
|
||
if (!thread_db_list)
|
||
unpush_target (ops);
|
||
}
|
||
|
||
struct callback_data
|
||
{
|
||
struct thread_db_info *info;
|
||
int new_threads;
|
||
};
|
||
|
||
static int
|
||
find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
|
||
{
|
||
td_thrinfo_t ti;
|
||
td_err_e err;
|
||
ptid_t ptid;
|
||
struct thread_info *tp;
|
||
struct callback_data *cb_data = (struct callback_data *) data;
|
||
struct thread_db_info *info = cb_data->info;
|
||
|
||
err = info->td_thr_get_info_p (th_p, &ti);
|
||
if (err != TD_OK)
|
||
error (_("find_new_threads_callback: cannot get thread info: %s"),
|
||
thread_db_err_str (err));
|
||
|
||
if (ti.ti_lid == -1)
|
||
{
|
||
/* A thread with kernel thread ID -1 is either a thread that
|
||
exited and was joined, or a thread that is being created but
|
||
hasn't started yet, and that is reusing the tcb/stack of a
|
||
thread that previously exited and was joined. (glibc marks
|
||
terminated and joined threads with kernel thread ID -1. See
|
||
glibc PR17707. */
|
||
if (libthread_db_debug)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"thread_db: skipping exited and "
|
||
"joined thread (0x%lx)\n",
|
||
(unsigned long) ti.ti_tid);
|
||
return 0;
|
||
}
|
||
|
||
if (ti.ti_tid == 0)
|
||
{
|
||
/* A thread ID of zero means that this is the main thread, but
|
||
glibc has not yet initialized thread-local storage and the
|
||
pthread library. We do not know what the thread's TID will
|
||
be yet. */
|
||
|
||
/* In that case, we're not stopped in a fork syscall and don't
|
||
need this glibc bug workaround. */
|
||
info->need_stale_parent_threads_check = 0;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Ignore stale parent threads, caused by glibc/BZ5983. This is a
|
||
bit expensive, as it needs to open /proc/pid/status, so try to
|
||
avoid doing the work if we know we don't have to. */
|
||
if (info->need_stale_parent_threads_check)
|
||
{
|
||
int tgid = linux_proc_get_tgid (ti.ti_lid);
|
||
|
||
if (tgid != -1 && tgid != info->pid)
|
||
return 0;
|
||
}
|
||
|
||
ptid = ptid_build (info->pid, ti.ti_lid, 0);
|
||
tp = find_thread_ptid (ptid);
|
||
if (tp == NULL || tp->priv == NULL)
|
||
record_thread (info, tp, ptid, th_p, &ti);
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Helper for thread_db_find_new_threads_2.
|
||
Returns number of new threads found. */
|
||
|
||
static int
|
||
find_new_threads_once (struct thread_db_info *info, int iteration,
|
||
td_err_e *errp)
|
||
{
|
||
struct callback_data data;
|
||
td_err_e err = TD_ERR;
|
||
|
||
data.info = info;
|
||
data.new_threads = 0;
|
||
|
||
/* See comment in thread_db_update_thread_list. */
|
||
gdb_assert (info->td_ta_thr_iter_p != NULL);
|
||
|
||
TRY
|
||
{
|
||
/* Iterate over all user-space threads to discover new threads. */
|
||
err = info->td_ta_thr_iter_p (info->thread_agent,
|
||
find_new_threads_callback,
|
||
&data,
|
||
TD_THR_ANY_STATE,
|
||
TD_THR_LOWEST_PRIORITY,
|
||
TD_SIGNO_MASK,
|
||
TD_THR_ANY_USER_FLAGS);
|
||
}
|
||
CATCH (except, RETURN_MASK_ERROR)
|
||
{
|
||
if (libthread_db_debug)
|
||
{
|
||
exception_fprintf (gdb_stdlog, except,
|
||
"Warning: find_new_threads_once: ");
|
||
}
|
||
}
|
||
END_CATCH
|
||
|
||
if (libthread_db_debug)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
_("Found %d new threads in iteration %d.\n"),
|
||
data.new_threads, iteration);
|
||
}
|
||
|
||
if (errp != NULL)
|
||
*errp = err;
|
||
|
||
return data.new_threads;
|
||
}
|
||
|
||
/* Search for new threads, accessing memory through stopped thread
|
||
PTID. If UNTIL_NO_NEW is true, repeat searching until several
|
||
searches in a row do not discover any new threads. */
|
||
|
||
static void
|
||
thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new)
|
||
{
|
||
td_err_e err = TD_OK;
|
||
struct thread_db_info *info;
|
||
int i, loop;
|
||
|
||
info = get_thread_db_info (ptid_get_pid (ptid));
|
||
|
||
/* Access an lwp we know is stopped. */
|
||
info->proc_handle.ptid = ptid;
|
||
|
||
if (until_no_new)
|
||
{
|
||
/* Require 4 successive iterations which do not find any new threads.
|
||
The 4 is a heuristic: there is an inherent race here, and I have
|
||
seen that 2 iterations in a row are not always sufficient to
|
||
"capture" all threads. */
|
||
for (i = 0, loop = 0; loop < 4 && err == TD_OK; ++i, ++loop)
|
||
if (find_new_threads_once (info, i, &err) != 0)
|
||
{
|
||
/* Found some new threads. Restart the loop from beginning. */
|
||
loop = -1;
|
||
}
|
||
}
|
||
else
|
||
find_new_threads_once (info, 0, &err);
|
||
|
||
if (err != TD_OK)
|
||
error (_("Cannot find new threads: %s"), thread_db_err_str (err));
|
||
}
|
||
|
||
static void
|
||
thread_db_find_new_threads_1 (ptid_t ptid)
|
||
{
|
||
thread_db_find_new_threads_2 (ptid, 0);
|
||
}
|
||
|
||
/* Implement the to_update_thread_list target method for this
|
||
target. */
|
||
|
||
static void
|
||
thread_db_update_thread_list (struct target_ops *ops)
|
||
{
|
||
struct thread_db_info *info;
|
||
struct inferior *inf;
|
||
|
||
prune_threads ();
|
||
|
||
ALL_INFERIORS (inf)
|
||
{
|
||
struct thread_info *thread;
|
||
|
||
if (inf->pid == 0)
|
||
continue;
|
||
|
||
info = get_thread_db_info (inf->pid);
|
||
if (info == NULL)
|
||
continue;
|
||
|
||
thread = any_live_thread_of_process (inf->pid);
|
||
if (thread == NULL || thread->executing)
|
||
continue;
|
||
|
||
/* It's best to avoid td_ta_thr_iter if possible. That walks
|
||
data structures in the inferior's address space that may be
|
||
corrupted, or, if the target is running, the list may change
|
||
while we walk it. In the latter case, it's possible that a
|
||
thread exits just at the exact time that causes GDB to get
|
||
stuck in an infinite loop. To avoid pausing all threads
|
||
whenever the core wants to refresh the thread list, we
|
||
instead use thread_from_lwp immediately when we see an LWP
|
||
stop. That uses thread_db entry points that do not walk
|
||
libpthread's thread list, so should be safe, as well as more
|
||
efficient. */
|
||
if (target_has_execution_1 (thread->ptid))
|
||
continue;
|
||
|
||
thread_db_find_new_threads_1 (thread->ptid);
|
||
}
|
||
|
||
/* Give the beneath target a chance to do extra processing. */
|
||
ops->beneath->to_update_thread_list (ops->beneath);
|
||
}
|
||
|
||
static const char *
|
||
thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid)
|
||
{
|
||
struct thread_info *thread_info = find_thread_ptid (ptid);
|
||
struct target_ops *beneath;
|
||
|
||
if (thread_info != NULL && thread_info->priv != NULL)
|
||
{
|
||
static char buf[64];
|
||
thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
|
||
|
||
snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
|
||
(unsigned long) priv->tid, ptid_get_lwp (ptid));
|
||
|
||
return buf;
|
||
}
|
||
|
||
beneath = find_target_beneath (ops);
|
||
return beneath->to_pid_to_str (beneath, ptid);
|
||
}
|
||
|
||
/* Return a string describing the state of the thread specified by
|
||
INFO. */
|
||
|
||
static const char *
|
||
thread_db_extra_thread_info (struct target_ops *self,
|
||
struct thread_info *info)
|
||
{
|
||
if (info->priv == NULL)
|
||
return NULL;
|
||
|
||
thread_db_thread_info *priv = get_thread_db_thread_info (info);
|
||
|
||
if (priv->dying)
|
||
return "Exiting";
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Return pointer to the thread_info struct which corresponds to
|
||
THREAD_HANDLE (having length HANDLE_LEN). */
|
||
|
||
static struct thread_info *
|
||
thread_db_thread_handle_to_thread_info (struct target_ops *ops,
|
||
const gdb_byte *thread_handle,
|
||
int handle_len,
|
||
struct inferior *inf)
|
||
{
|
||
struct thread_info *tp;
|
||
thread_t handle_tid;
|
||
|
||
/* Thread handle sizes must match in order to proceed. We don't use an
|
||
assert here because the resulting internal error will cause GDB to
|
||
exit. This isn't necessarily an internal error due to the possibility
|
||
of garbage being passed as the thread handle via the python interface. */
|
||
if (handle_len != sizeof (handle_tid))
|
||
error (_("Thread handle size mismatch: %d vs %zu (from libthread_db)"),
|
||
handle_len, sizeof (handle_tid));
|
||
|
||
handle_tid = * (const thread_t *) thread_handle;
|
||
|
||
ALL_NON_EXITED_THREADS (tp)
|
||
{
|
||
thread_db_thread_info *priv = get_thread_db_thread_info (tp);
|
||
|
||
if (tp->inf == inf && priv != NULL && handle_tid == priv->tid)
|
||
return tp;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Get the address of the thread local variable in load module LM which
|
||
is stored at OFFSET within the thread local storage for thread PTID. */
|
||
|
||
static CORE_ADDR
|
||
thread_db_get_thread_local_address (struct target_ops *ops,
|
||
ptid_t ptid,
|
||
CORE_ADDR lm,
|
||
CORE_ADDR offset)
|
||
{
|
||
struct thread_info *thread_info;
|
||
struct target_ops *beneath;
|
||
|
||
/* Find the matching thread. */
|
||
thread_info = find_thread_ptid (ptid);
|
||
|
||
/* We may not have discovered the thread yet. */
|
||
if (thread_info != NULL && thread_info->priv == NULL)
|
||
thread_info = thread_from_lwp (ptid);
|
||
|
||
if (thread_info != NULL && thread_info->priv != NULL)
|
||
{
|
||
td_err_e err;
|
||
psaddr_t address;
|
||
thread_db_info *info = get_thread_db_info (ptid_get_pid (ptid));
|
||
thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
|
||
|
||
/* Finally, get the address of the variable. */
|
||
if (lm != 0)
|
||
{
|
||
/* glibc doesn't provide the needed interface. */
|
||
if (!info->td_thr_tls_get_addr_p)
|
||
throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
|
||
_("No TLS library support"));
|
||
|
||
/* Note the cast through uintptr_t: this interface only works if
|
||
a target address fits in a psaddr_t, which is a host pointer.
|
||
So a 32-bit debugger can not access 64-bit TLS through this. */
|
||
err = info->td_thr_tls_get_addr_p (&priv->th,
|
||
(psaddr_t)(uintptr_t) lm,
|
||
offset, &address);
|
||
}
|
||
else
|
||
{
|
||
/* If glibc doesn't provide the needed interface throw an error
|
||
that LM is zero - normally cases it should not be. */
|
||
if (!info->td_thr_tlsbase_p)
|
||
throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
|
||
_("TLS load module not found"));
|
||
|
||
/* This code path handles the case of -static -pthread executables:
|
||
https://sourceware.org/ml/libc-help/2014-03/msg00024.html
|
||
For older GNU libc r_debug.r_map is NULL. For GNU libc after
|
||
PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
|
||
The constant number 1 depends on GNU __libc_setup_tls
|
||
initialization of l_tls_modid to 1. */
|
||
err = info->td_thr_tlsbase_p (&priv->th, 1, &address);
|
||
address = (char *) address + offset;
|
||
}
|
||
|
||
#ifdef THREAD_DB_HAS_TD_NOTALLOC
|
||
/* The memory hasn't been allocated, yet. */
|
||
if (err == TD_NOTALLOC)
|
||
/* Now, if libthread_db provided the initialization image's
|
||
address, we *could* try to build a non-lvalue value from
|
||
the initialization image. */
|
||
throw_error (TLS_NOT_ALLOCATED_YET_ERROR,
|
||
_("TLS not allocated yet"));
|
||
#endif
|
||
|
||
/* Something else went wrong. */
|
||
if (err != TD_OK)
|
||
throw_error (TLS_GENERIC_ERROR,
|
||
(("%s")), thread_db_err_str (err));
|
||
|
||
/* Cast assuming host == target. Joy. */
|
||
/* Do proper sign extension for the target. */
|
||
gdb_assert (exec_bfd);
|
||
return (bfd_get_sign_extend_vma (exec_bfd) > 0
|
||
? (CORE_ADDR) (intptr_t) address
|
||
: (CORE_ADDR) (uintptr_t) address);
|
||
}
|
||
|
||
beneath = find_target_beneath (ops);
|
||
return beneath->to_get_thread_local_address (beneath, ptid, lm, offset);
|
||
}
|
||
|
||
/* Implement the to_get_ada_task_ptid target method for this target. */
|
||
|
||
static ptid_t
|
||
thread_db_get_ada_task_ptid (struct target_ops *self, long lwp, long thread)
|
||
{
|
||
/* NPTL uses a 1:1 model, so the LWP id suffices. */
|
||
return ptid_build (ptid_get_pid (inferior_ptid), lwp, 0);
|
||
}
|
||
|
||
static void
|
||
thread_db_resume (struct target_ops *ops,
|
||
ptid_t ptid, int step, enum gdb_signal signo)
|
||
{
|
||
struct target_ops *beneath = find_target_beneath (ops);
|
||
struct thread_db_info *info;
|
||
|
||
if (ptid_equal (ptid, minus_one_ptid))
|
||
info = get_thread_db_info (ptid_get_pid (inferior_ptid));
|
||
else
|
||
info = get_thread_db_info (ptid_get_pid (ptid));
|
||
|
||
/* This workaround is only needed for child fork lwps stopped in a
|
||
PTRACE_O_TRACEFORK event. When the inferior is resumed, the
|
||
workaround can be disabled. */
|
||
if (info)
|
||
info->need_stale_parent_threads_check = 0;
|
||
|
||
beneath->to_resume (beneath, ptid, step, signo);
|
||
}
|
||
|
||
/* qsort helper function for info_auto_load_libthread_db, sort the
|
||
thread_db_info pointers primarily by their FILENAME and secondarily by their
|
||
PID, both in ascending order. */
|
||
|
||
static int
|
||
info_auto_load_libthread_db_compare (const void *ap, const void *bp)
|
||
{
|
||
struct thread_db_info *a = *(struct thread_db_info **) ap;
|
||
struct thread_db_info *b = *(struct thread_db_info **) bp;
|
||
int retval;
|
||
|
||
retval = strcmp (a->filename, b->filename);
|
||
if (retval)
|
||
return retval;
|
||
|
||
return (a->pid > b->pid) - (a->pid - b->pid);
|
||
}
|
||
|
||
/* Implement 'info auto-load libthread-db'. */
|
||
|
||
static void
|
||
info_auto_load_libthread_db (const char *args, int from_tty)
|
||
{
|
||
struct ui_out *uiout = current_uiout;
|
||
const char *cs = args ? args : "";
|
||
struct thread_db_info *info, **array;
|
||
unsigned info_count, unique_filenames;
|
||
size_t max_filename_len, max_pids_len, pids_len;
|
||
struct cleanup *back_to;
|
||
char *pids;
|
||
int i;
|
||
|
||
cs = skip_spaces (cs);
|
||
if (*cs)
|
||
error (_("'info auto-load libthread-db' does not accept any parameters"));
|
||
|
||
info_count = 0;
|
||
for (info = thread_db_list; info; info = info->next)
|
||
if (info->filename != NULL)
|
||
info_count++;
|
||
|
||
array = XNEWVEC (struct thread_db_info *, info_count);
|
||
back_to = make_cleanup (xfree, array);
|
||
|
||
info_count = 0;
|
||
for (info = thread_db_list; info; info = info->next)
|
||
if (info->filename != NULL)
|
||
array[info_count++] = info;
|
||
|
||
/* Sort ARRAY by filenames and PIDs. */
|
||
|
||
qsort (array, info_count, sizeof (*array),
|
||
info_auto_load_libthread_db_compare);
|
||
|
||
/* Calculate the number of unique filenames (rows) and the maximum string
|
||
length of PIDs list for the unique filenames (columns). */
|
||
|
||
unique_filenames = 0;
|
||
max_filename_len = 0;
|
||
max_pids_len = 0;
|
||
pids_len = 0;
|
||
for (i = 0; i < info_count; i++)
|
||
{
|
||
int pid = array[i]->pid;
|
||
size_t this_pid_len;
|
||
|
||
for (this_pid_len = 0; pid != 0; pid /= 10)
|
||
this_pid_len++;
|
||
|
||
if (i == 0 || strcmp (array[i - 1]->filename, array[i]->filename) != 0)
|
||
{
|
||
unique_filenames++;
|
||
max_filename_len = std::max (max_filename_len,
|
||
strlen (array[i]->filename));
|
||
|
||
if (i > 0)
|
||
{
|
||
pids_len -= strlen (", ");
|
||
max_pids_len = std::max (max_pids_len, pids_len);
|
||
}
|
||
pids_len = 0;
|
||
}
|
||
pids_len += this_pid_len + strlen (", ");
|
||
}
|
||
if (i)
|
||
{
|
||
pids_len -= strlen (", ");
|
||
max_pids_len = std::max (max_pids_len, pids_len);
|
||
}
|
||
|
||
/* Table header shifted right by preceding "libthread-db: " would not match
|
||
its columns. */
|
||
if (info_count > 0 && args == auto_load_info_scripts_pattern_nl)
|
||
uiout->text ("\n");
|
||
|
||
{
|
||
ui_out_emit_table table_emitter (uiout, 2, unique_filenames,
|
||
"LinuxThreadDbTable");
|
||
|
||
uiout->table_header (max_filename_len, ui_left, "filename", "Filename");
|
||
uiout->table_header (pids_len, ui_left, "PIDs", "Pids");
|
||
uiout->table_body ();
|
||
|
||
pids = (char *) xmalloc (max_pids_len + 1);
|
||
make_cleanup (xfree, pids);
|
||
|
||
/* Note I is incremented inside the cycle, not at its end. */
|
||
for (i = 0; i < info_count;)
|
||
{
|
||
ui_out_emit_tuple tuple_emitter (uiout, NULL);
|
||
char *pids_end;
|
||
|
||
info = array[i];
|
||
uiout->field_string ("filename", info->filename);
|
||
pids_end = pids;
|
||
|
||
while (i < info_count && strcmp (info->filename,
|
||
array[i]->filename) == 0)
|
||
{
|
||
if (pids_end != pids)
|
||
{
|
||
*pids_end++ = ',';
|
||
*pids_end++ = ' ';
|
||
}
|
||
pids_end += xsnprintf (pids_end,
|
||
&pids[max_pids_len + 1] - pids_end,
|
||
"%u", array[i]->pid);
|
||
gdb_assert (pids_end < &pids[max_pids_len + 1]);
|
||
|
||
i++;
|
||
}
|
||
*pids_end = '\0';
|
||
|
||
uiout->field_string ("pids", pids);
|
||
|
||
uiout->text ("\n");
|
||
}
|
||
}
|
||
|
||
do_cleanups (back_to);
|
||
|
||
if (info_count == 0)
|
||
uiout->message (_("No auto-loaded libthread-db.\n"));
|
||
}
|
||
|
||
static void
|
||
init_thread_db_ops (void)
|
||
{
|
||
thread_db_ops.to_shortname = "multi-thread";
|
||
thread_db_ops.to_longname = "multi-threaded child process.";
|
||
thread_db_ops.to_doc = "Threads and pthreads support.";
|
||
thread_db_ops.to_detach = thread_db_detach;
|
||
thread_db_ops.to_wait = thread_db_wait;
|
||
thread_db_ops.to_resume = thread_db_resume;
|
||
thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior;
|
||
thread_db_ops.to_update_thread_list = thread_db_update_thread_list;
|
||
thread_db_ops.to_pid_to_str = thread_db_pid_to_str;
|
||
thread_db_ops.to_stratum = thread_stratum;
|
||
thread_db_ops.to_has_thread_control = tc_schedlock;
|
||
thread_db_ops.to_get_thread_local_address
|
||
= thread_db_get_thread_local_address;
|
||
thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info;
|
||
thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid;
|
||
thread_db_ops.to_thread_handle_to_thread_info = thread_db_thread_handle_to_thread_info;
|
||
thread_db_ops.to_magic = OPS_MAGIC;
|
||
|
||
complete_target_initialization (&thread_db_ops);
|
||
}
|
||
|
||
void
|
||
_initialize_thread_db (void)
|
||
{
|
||
init_thread_db_ops ();
|
||
|
||
/* Defer loading of libthread_db.so until inferior is running.
|
||
This allows gdb to load correct libthread_db for a given
|
||
executable -- there could be multiple versions of glibc,
|
||
and until there is a running inferior, we can't tell which
|
||
libthread_db is the correct one to load. */
|
||
|
||
libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
|
||
|
||
add_setshow_optional_filename_cmd ("libthread-db-search-path",
|
||
class_support,
|
||
&libthread_db_search_path, _("\
|
||
Set search path for libthread_db."), _("\
|
||
Show the current search path or libthread_db."), _("\
|
||
This path is used to search for libthread_db to be loaded into \
|
||
gdb itself.\n\
|
||
Its value is a colon (':') separate list of directories to search.\n\
|
||
Setting the search path to an empty list resets it to its default value."),
|
||
set_libthread_db_search_path,
|
||
NULL,
|
||
&setlist, &showlist);
|
||
|
||
add_setshow_zuinteger_cmd ("libthread-db", class_maintenance,
|
||
&libthread_db_debug, _("\
|
||
Set libthread-db debugging."), _("\
|
||
Show libthread-db debugging."), _("\
|
||
When non-zero, libthread-db debugging is enabled."),
|
||
NULL,
|
||
show_libthread_db_debug,
|
||
&setdebuglist, &showdebuglist);
|
||
|
||
add_setshow_boolean_cmd ("libthread-db", class_support,
|
||
&auto_load_thread_db, _("\
|
||
Enable or disable auto-loading of inferior specific libthread_db."), _("\
|
||
Show whether auto-loading inferior specific libthread_db is enabled."), _("\
|
||
If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
|
||
locations to load libthread_db compatible with the inferior.\n\
|
||
Standard system libthread_db still gets loaded even with this option off.\n\
|
||
This options has security implications for untrusted inferiors."),
|
||
NULL, show_auto_load_thread_db,
|
||
auto_load_set_cmdlist_get (),
|
||
auto_load_show_cmdlist_get ());
|
||
|
||
add_cmd ("libthread-db", class_info, info_auto_load_libthread_db,
|
||
_("Print the list of loaded inferior specific libthread_db.\n\
|
||
Usage: info auto-load libthread-db"),
|
||
auto_load_info_cmdlist_get ());
|
||
|
||
/* Add ourselves to objfile event chain. */
|
||
observer_attach_new_objfile (thread_db_new_objfile);
|
||
|
||
/* Add ourselves to inferior_created event chain.
|
||
This is needed to handle debugging statically linked programs where
|
||
the new_objfile observer won't get called for libpthread. */
|
||
observer_attach_inferior_created (thread_db_inferior_created);
|
||
}
|