1849 lines
52 KiB
C
1849 lines
52 KiB
C
/* libthread_db assisted debugging support, generic parts.
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Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
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2010, 2011 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 "gdb_assert.h"
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#include <dlfcn.h>
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#include "gdb_proc_service.h"
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#include "gdb_thread_db.h"
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#include "bfd.h"
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#include "command.h"
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#include "exceptions.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 "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 "linux-procfs.h"
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#include <signal.h>
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#ifdef HAVE_GNU_LIBC_VERSION_H
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#include <gnu/libc-version.h>
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#endif
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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
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both more powerful and more complicated. This implementation
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only works for LinuxThreads and NPTL, the two glibc threading
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libraries. It assumes that each thread is permanently assigned
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to a single light-weight process (LWP).
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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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static void
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set_libthread_db_search_path (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 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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/* 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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/* Location of the thread creation event breakpoint. The code at
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this location in the child process will be called by the pthread
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library whenever a new thread is created. By setting a special
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breakpoint at this location, GDB can detect when a new thread is
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created. We obtain this location via the td_ta_event_addr
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call. */
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CORE_ADDR td_create_bp_addr;
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/* Location of the thread death event breakpoint. */
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CORE_ADDR td_death_bp_addr;
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/* Pointers to the libthread_db functions. */
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td_err_e (*td_init_p) (void);
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td_err_e (*td_ta_new_p) (struct ps_prochandle * ps,
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td_thragent_t **ta);
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td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt,
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td_thrhandle_t *__th);
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td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta,
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lwpid_t lwpid, td_thrhandle_t *th);
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td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta,
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td_thr_iter_f *callback, void *cbdata_p,
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td_thr_state_e state, int ti_pri,
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sigset_t *ti_sigmask_p,
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unsigned int ti_user_flags);
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td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta,
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td_event_e event, td_notify_t *ptr);
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td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta,
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td_thr_events_t *event);
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td_err_e (*td_ta_clear_event_p) (const td_thragent_t *ta,
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td_thr_events_t *event);
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td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
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td_event_msg_t *msg);
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td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th);
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td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th,
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td_thrinfo_t *infop);
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td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th,
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int event);
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td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
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psaddr_t map_address,
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size_t offset, psaddr_t *address);
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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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/* 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;
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info = xcalloc (1, sizeof (*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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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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/* Prototypes for local functions. */
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static int attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
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const td_thrinfo_t *ti_p);
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static void detach_thread (ptid_t ptid);
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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 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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unsigned int dying:1;
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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 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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/* Return 1 if any threads have been registered. There may be none if
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the threading library is not fully initialized yet. */
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static int
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have_threads_callback (struct thread_info *thread, void *args)
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{
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int pid = * (int *) args;
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if (ptid_get_pid (thread->ptid) != pid)
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return 0;
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return thread->private != NULL;
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}
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static int
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have_threads (ptid_t ptid)
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{
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int pid = ptid_get_pid (ptid);
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return iterate_over_threads (have_threads_callback, &pid) != NULL;
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}
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struct thread_get_info_inout
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{
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struct thread_info *thread_info;
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struct thread_db_info *thread_db_info;
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};
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/* A callback function for td_ta_thr_iter, which we use to map all
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threads to LWPs.
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THP is a handle to the current thread; if INFOP is not NULL, the
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struct thread_info associated with this thread is returned in
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*INFOP.
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If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise,
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zero is returned to indicate success. */
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static int
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thread_get_info_callback (const td_thrhandle_t *thp, void *argp)
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{
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td_thrinfo_t ti;
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td_err_e err;
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ptid_t thread_ptid;
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struct thread_get_info_inout *inout;
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struct thread_db_info *info;
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inout = argp;
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info = inout->thread_db_info;
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err = info->td_thr_get_info_p (thp, &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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thread_ptid = ptid_build (info->pid, ti.ti_lid, 0);
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inout->thread_info = find_thread_ptid (thread_ptid);
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/* In the case of a zombie thread, don't continue. We don't want to
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attach to it thinking it is a new thread. */
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if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
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return TD_THR_ZOMBIE;
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if (inout->thread_info == NULL)
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{
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/* New thread. Attach to it now (why wait?). */
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if (!have_threads (thread_ptid))
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thread_db_find_new_threads_1 (thread_ptid);
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else
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attach_thread (thread_ptid, thp, &ti);
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||
inout->thread_info = find_thread_ptid (thread_ptid);
|
||
gdb_assert (inout->thread_info != NULL);
|
||
}
|
||
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||
return 0;
|
||
}
|
||
|
||
/* Convert between user-level thread ids and LWP ids. */
|
||
|
||
static ptid_t
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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_err_e err;
|
||
struct thread_db_info *info;
|
||
struct thread_get_info_inout io = {0};
|
||
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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
|
||
LWP. */
|
||
gdb_assert (GET_LWP (ptid) != 0);
|
||
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||
info = get_thread_db_info (GET_PID (ptid));
|
||
|
||
/* 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, GET_LWP (ptid), &th);
|
||
if (err != TD_OK)
|
||
error (_("Cannot find user-level thread for LWP %ld: %s"),
|
||
GET_LWP (ptid), thread_db_err_str (err));
|
||
|
||
/* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the
|
||
event thread has already died. If another gdb interface has called
|
||
thread_alive() previously, the thread won't be found on the thread list
|
||
anymore. In that case, we don't want to process this ptid anymore
|
||
to avoid the possibility of later treating it as a newly
|
||
discovered thread id that we should add to the list. Thus,
|
||
we return a -1 ptid which is also how the thread list marks a
|
||
dead thread. */
|
||
io.thread_db_info = info;
|
||
io.thread_info = NULL;
|
||
if (thread_get_info_callback (&th, &io) == TD_THR_ZOMBIE
|
||
&& io.thread_info == NULL)
|
||
return minus_one_ptid;
|
||
|
||
gdb_assert (ptid_get_tid (ptid) == 0);
|
||
return ptid;
|
||
}
|
||
|
||
|
||
/* Attach to lwp PTID, doing whatever else is required to have this
|
||
LWP under the debugger's control --- e.g., enabling event
|
||
reporting. Returns true on success. */
|
||
int
|
||
thread_db_attach_lwp (ptid_t ptid)
|
||
{
|
||
td_thrhandle_t th;
|
||
td_thrinfo_t ti;
|
||
td_err_e err;
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (GET_PID (ptid));
|
||
|
||
if (info == NULL)
|
||
return 0;
|
||
|
||
/* This ptid comes from linux-nat.c, which should always fill in the
|
||
LWP. */
|
||
gdb_assert (GET_LWP (ptid) != 0);
|
||
|
||
/* Access an lwp we know is stopped. */
|
||
info->proc_handle.ptid = ptid;
|
||
|
||
/* If we have only looked at the first thread before libpthread was
|
||
initialized, we may not know its thread ID yet. Make sure we do
|
||
before we add another thread to the list. */
|
||
if (!have_threads (ptid))
|
||
thread_db_find_new_threads_1 (ptid);
|
||
|
||
err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th);
|
||
if (err != TD_OK)
|
||
/* Cannot find user-level thread. */
|
||
return 0;
|
||
|
||
err = info->td_thr_get_info_p (&th, &ti);
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Cannot get thread info: %s"), thread_db_err_str (err));
|
||
return 0;
|
||
}
|
||
|
||
attach_thread (ptid, &th, &ti);
|
||
return 1;
|
||
}
|
||
|
||
static void *
|
||
verbose_dlsym (void *handle, const char *name)
|
||
{
|
||
void *sym = dlsym (handle, name);
|
||
if (sym == NULL)
|
||
warning (_("Symbol \"%s\" not found in libthread_db: %s"),
|
||
name, dlerror ());
|
||
return sym;
|
||
}
|
||
|
||
static td_err_e
|
||
enable_thread_event (int event, CORE_ADDR *bp)
|
||
{
|
||
td_notify_t notify;
|
||
td_err_e err;
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (GET_PID (inferior_ptid));
|
||
|
||
/* Access an lwp we know is stopped. */
|
||
info->proc_handle.ptid = inferior_ptid;
|
||
|
||
/* Get the breakpoint address for thread EVENT. */
|
||
err = info->td_ta_event_addr_p (info->thread_agent, event, ¬ify);
|
||
if (err != TD_OK)
|
||
return err;
|
||
|
||
/* Set up the breakpoint. */
|
||
gdb_assert (exec_bfd);
|
||
(*bp) = (gdbarch_convert_from_func_ptr_addr
|
||
(target_gdbarch,
|
||
/* Do proper sign extension for the target. */
|
||
(bfd_get_sign_extend_vma (exec_bfd) > 0
|
||
? (CORE_ADDR) (intptr_t) notify.u.bptaddr
|
||
: (CORE_ADDR) (uintptr_t) notify.u.bptaddr),
|
||
¤t_target));
|
||
create_thread_event_breakpoint (target_gdbarch, *bp);
|
||
|
||
return TD_OK;
|
||
}
|
||
|
||
static void
|
||
enable_thread_event_reporting (void)
|
||
{
|
||
td_thr_events_t events;
|
||
td_err_e err;
|
||
#ifdef HAVE_GNU_LIBC_VERSION_H
|
||
const char *libc_version;
|
||
int libc_major, libc_minor;
|
||
#endif
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (GET_PID (inferior_ptid));
|
||
|
||
/* We cannot use the thread event reporting facility if these
|
||
functions aren't available. */
|
||
if (info->td_ta_event_addr_p == NULL
|
||
|| info->td_ta_set_event_p == NULL
|
||
|| info->td_ta_event_getmsg_p == NULL
|
||
|| info->td_thr_event_enable_p == NULL)
|
||
return;
|
||
|
||
/* Set the process wide mask saying which events we're interested in. */
|
||
td_event_emptyset (&events);
|
||
td_event_addset (&events, TD_CREATE);
|
||
|
||
#ifdef HAVE_GNU_LIBC_VERSION_H
|
||
/* The event reporting facility is broken for TD_DEATH events in
|
||
glibc 2.1.3, so don't enable it if we have glibc but a lower
|
||
version. */
|
||
libc_version = gnu_get_libc_version ();
|
||
if (sscanf (libc_version, "%d.%d", &libc_major, &libc_minor) == 2
|
||
&& (libc_major > 2 || (libc_major == 2 && libc_minor > 1)))
|
||
#endif
|
||
td_event_addset (&events, TD_DEATH);
|
||
|
||
err = info->td_ta_set_event_p (info->thread_agent, &events);
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Unable to set global thread event mask: %s"),
|
||
thread_db_err_str (err));
|
||
return;
|
||
}
|
||
|
||
/* Delete previous thread event breakpoints, if any. */
|
||
remove_thread_event_breakpoints ();
|
||
info->td_create_bp_addr = 0;
|
||
info->td_death_bp_addr = 0;
|
||
|
||
/* Set up the thread creation event. */
|
||
err = enable_thread_event (TD_CREATE, &info->td_create_bp_addr);
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Unable to get location for thread creation breakpoint: %s"),
|
||
thread_db_err_str (err));
|
||
return;
|
||
}
|
||
|
||
/* Set up the thread death event. */
|
||
err = enable_thread_event (TD_DEATH, &info->td_death_bp_addr);
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Unable to get location for thread death breakpoint: %s"),
|
||
thread_db_err_str (err));
|
||
return;
|
||
}
|
||
}
|
||
|
||
/* Same as thread_db_find_new_threads_1, but silently ignore errors. */
|
||
|
||
static void
|
||
thread_db_find_new_threads_silently (ptid_t ptid)
|
||
{
|
||
volatile struct gdb_exception except;
|
||
|
||
TRY_CATCH (except, RETURN_MASK_ERROR)
|
||
{
|
||
thread_db_find_new_threads_2 (ptid, 1);
|
||
}
|
||
|
||
if (except.reason < 0 && libthread_db_debug)
|
||
{
|
||
exception_fprintf (gdb_stderr, except,
|
||
"Warning: thread_db_find_new_threads_silently: ");
|
||
}
|
||
}
|
||
|
||
/* 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. */
|
||
|
||
info->td_init_p = verbose_dlsym (info->handle, "td_init");
|
||
if (info->td_init_p == NULL)
|
||
return 0;
|
||
|
||
err = info->td_init_p ();
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Cannot initialize libthread_db: %s"),
|
||
thread_db_err_str (err));
|
||
return 0;
|
||
}
|
||
|
||
info->td_ta_new_p = verbose_dlsym (info->handle, "td_ta_new");
|
||
if (info->td_ta_new_p == NULL)
|
||
return 0;
|
||
|
||
/* 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)
|
||
printf_unfiltered (_("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;
|
||
}
|
||
|
||
info->td_ta_map_id2thr_p = verbose_dlsym (info->handle, "td_ta_map_id2thr");
|
||
if (info->td_ta_map_id2thr_p == NULL)
|
||
return 0;
|
||
|
||
info->td_ta_map_lwp2thr_p = verbose_dlsym (info->handle,
|
||
"td_ta_map_lwp2thr");
|
||
if (info->td_ta_map_lwp2thr_p == NULL)
|
||
return 0;
|
||
|
||
info->td_ta_thr_iter_p = verbose_dlsym (info->handle, "td_ta_thr_iter");
|
||
if (info->td_ta_thr_iter_p == NULL)
|
||
return 0;
|
||
|
||
info->td_thr_validate_p = verbose_dlsym (info->handle, "td_thr_validate");
|
||
if (info->td_thr_validate_p == NULL)
|
||
return 0;
|
||
|
||
info->td_thr_get_info_p = verbose_dlsym (info->handle, "td_thr_get_info");
|
||
if (info->td_thr_get_info_p == NULL)
|
||
return 0;
|
||
|
||
/* These are not essential. */
|
||
info->td_ta_event_addr_p = dlsym (info->handle, "td_ta_event_addr");
|
||
info->td_ta_set_event_p = dlsym (info->handle, "td_ta_set_event");
|
||
info->td_ta_clear_event_p = dlsym (info->handle, "td_ta_clear_event");
|
||
info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg");
|
||
info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable");
|
||
info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr");
|
||
|
||
printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
|
||
|
||
if (libthread_db_debug || *libthread_db_search_path)
|
||
{
|
||
const char *library;
|
||
|
||
library = dladdr_to_soname (*info->td_ta_new_p);
|
||
if (library == NULL)
|
||
library = LIBTHREAD_DB_SO;
|
||
|
||
printf_unfiltered (_("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);
|
||
|
||
/* Enable event reporting, but not when debugging a core file. */
|
||
if (target_has_execution)
|
||
enable_thread_event_reporting ();
|
||
|
||
/* There appears to be a bug in glibc-2.3.6: 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. Silently ignore such
|
||
errors, and let gdb enumerate threads again later. */
|
||
thread_db_find_new_threads_silently (inferior_ptid);
|
||
|
||
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)
|
||
{
|
||
void *handle;
|
||
struct thread_db_info *info;
|
||
|
||
if (libthread_db_debug)
|
||
printf_unfiltered (_("Trying host libthread_db library: %s.\n"),
|
||
library);
|
||
handle = dlopen (library, RTLD_NOW);
|
||
if (handle == NULL)
|
||
{
|
||
if (libthread_db_debug)
|
||
printf_unfiltered (_("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)
|
||
printf_unfiltered (_("Host %s resolved to: %s.\n"),
|
||
library, libpath);
|
||
}
|
||
}
|
||
|
||
info = add_thread_db_info (handle);
|
||
|
||
if (try_thread_db_load_1 (info))
|
||
return 1;
|
||
|
||
/* This library "refused" to work on current inferior. */
|
||
delete_thread_db_info (GET_PID (inferior_ptid));
|
||
return 0;
|
||
}
|
||
|
||
/* Subroutine of try_thread_db_load_from_pdir to simplify it.
|
||
Try loading libthread_db from the same directory as OBJ.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_pdir_1 (struct objfile *obj)
|
||
{
|
||
struct cleanup *cleanup;
|
||
char *path, *cp;
|
||
int result;
|
||
|
||
if (obj->name[0] != '/')
|
||
{
|
||
warning (_("Expected absolute pathname for libpthread in the"
|
||
" inferior, but got %s."), obj->name);
|
||
return 0;
|
||
}
|
||
|
||
path = xmalloc (strlen (obj->name) + 1 + strlen (LIBTHREAD_DB_SO) + 1);
|
||
cleanup = make_cleanup (xfree, path);
|
||
|
||
strcpy (path, obj->name);
|
||
cp = strrchr (path, '/');
|
||
/* This should at minimum hit the first character. */
|
||
gdb_assert (cp != NULL);
|
||
strcpy (cp + 1, LIBTHREAD_DB_SO);
|
||
result = try_thread_db_load (path);
|
||
|
||
do_cleanups (cleanup);
|
||
return result;
|
||
}
|
||
|
||
/* Handle $pdir in libthread-db-search-path.
|
||
Look for libthread_db in the directory of libpthread.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_pdir (void)
|
||
{
|
||
struct objfile *obj;
|
||
|
||
ALL_OBJFILES (obj)
|
||
if (libpthread_name_p (obj->name))
|
||
{
|
||
if (try_thread_db_load_from_pdir_1 (obj))
|
||
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);
|
||
|
||
return 0;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Handle $sdir in libthread-db-search-path.
|
||
Look for libthread_db in the system dirs, or wherever a plain
|
||
dlopen(file_without_path) will look.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_sdir (void)
|
||
{
|
||
return try_thread_db_load (LIBTHREAD_DB_SO);
|
||
}
|
||
|
||
/* Try to load libthread_db from directory DIR of length DIR_LEN.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
try_thread_db_load_from_dir (const char *dir, size_t dir_len)
|
||
{
|
||
struct cleanup *cleanup;
|
||
char *path;
|
||
int result;
|
||
|
||
path = xmalloc (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1);
|
||
cleanup = make_cleanup (xfree, path);
|
||
|
||
memcpy (path, dir, dir_len);
|
||
path[dir_len] = '/';
|
||
strcpy (path + dir_len + 1, LIBTHREAD_DB_SO);
|
||
result = try_thread_db_load (path);
|
||
|
||
do_cleanups (cleanup);
|
||
return result;
|
||
}
|
||
|
||
/* Search libthread_db_search_path for libthread_db which "agrees"
|
||
to work on current inferior.
|
||
The result is true for success. */
|
||
|
||
static int
|
||
thread_db_load_search (void)
|
||
{
|
||
const char *search_path = libthread_db_search_path;
|
||
int rc = 0;
|
||
|
||
while (*search_path)
|
||
{
|
||
const char *end = strchr (search_path, ':');
|
||
const char *this_dir = search_path;
|
||
size_t this_dir_len;
|
||
|
||
if (end)
|
||
{
|
||
this_dir_len = end - search_path;
|
||
search_path += this_dir_len + 1;
|
||
}
|
||
else
|
||
{
|
||
this_dir_len = strlen (this_dir);
|
||
search_path += this_dir_len;
|
||
}
|
||
|
||
if (this_dir_len == sizeof ("$pdir") - 1
|
||
&& strncmp (this_dir, "$pdir", this_dir_len) == 0)
|
||
{
|
||
if (try_thread_db_load_from_pdir ())
|
||
{
|
||
rc = 1;
|
||
break;
|
||
}
|
||
}
|
||
else if (this_dir_len == sizeof ("$sdir") - 1
|
||
&& strncmp (this_dir, "$sdir", this_dir_len) == 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;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (libthread_db_debug)
|
||
printf_unfiltered (_("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 (obj->name))
|
||
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 (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
|
||
disable_thread_event_reporting (struct thread_db_info *info)
|
||
{
|
||
if (info->td_ta_clear_event_p != NULL)
|
||
{
|
||
td_thr_events_t events;
|
||
|
||
/* Set the process wide mask saying we aren't interested in any
|
||
events anymore. */
|
||
td_event_fillset (&events);
|
||
info->td_ta_clear_event_p (info->thread_agent, &events);
|
||
}
|
||
|
||
info->td_create_bp_addr = 0;
|
||
info->td_death_bp_addr = 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 (target_signal_from_host (i), 0))
|
||
sigaddset (&thread_stop_set, i);
|
||
if (signal_print_update (target_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;
|
||
}
|
||
|
||
static void
|
||
thread_db_new_objfile (struct objfile *objfile)
|
||
{
|
||
/* This observer must always be called with inferior_ptid set
|
||
correctly. */
|
||
|
||
if (objfile != NULL)
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
/* Attach to a new thread. This function is called when we receive a
|
||
TD_CREATE event or when we iterate over all threads and find one
|
||
that wasn't already in our list. Returns true on success. */
|
||
|
||
static int
|
||
attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
|
||
const td_thrinfo_t *ti_p)
|
||
{
|
||
struct private_thread_info *private;
|
||
struct thread_info *tp = NULL;
|
||
td_err_e err;
|
||
struct thread_db_info *info;
|
||
|
||
/* If we're being called after a TD_CREATE event, we may already
|
||
know about this thread. There are two ways this can happen. We
|
||
may have iterated over all threads between the thread creation
|
||
and the TD_CREATE event, for instance when the user has issued
|
||
the `info threads' command before the SIGTRAP for hitting the
|
||
thread creation breakpoint was reported. Alternatively, the
|
||
thread may have exited and a new one been created with the same
|
||
thread ID. In the first case we don't need to do anything; in
|
||
the second case we should discard information about the dead
|
||
thread and attach to the new one. */
|
||
if (in_thread_list (ptid))
|
||
{
|
||
tp = find_thread_ptid (ptid);
|
||
gdb_assert (tp != NULL);
|
||
|
||
/* If tp->private is NULL, then GDB is already attached to this
|
||
thread, but we do not know anything about it. We can learn
|
||
about it here. This can only happen if we have some other
|
||
way besides libthread_db to notice new threads (i.e.
|
||
PTRACE_EVENT_CLONE); assume the same mechanism notices thread
|
||
exit, so this can not be a stale thread recreated with the
|
||
same ID. */
|
||
if (tp->private != NULL)
|
||
{
|
||
if (!tp->private->dying)
|
||
return 0;
|
||
|
||
delete_thread (ptid);
|
||
tp = NULL;
|
||
}
|
||
}
|
||
|
||
if (target_has_execution)
|
||
check_thread_signals ();
|
||
|
||
if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
|
||
return 0; /* A zombie thread -- do not attach. */
|
||
|
||
/* Under GNU/Linux, we have to attach to each and every thread. */
|
||
if (target_has_execution
|
||
&& tp == NULL)
|
||
{
|
||
int res;
|
||
|
||
res = lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)));
|
||
if (res < 0)
|
||
{
|
||
/* Error, stop iterating. */
|
||
return 0;
|
||
}
|
||
else if (res > 0)
|
||
{
|
||
/* Pretend this thread doesn't exist yet, and keep
|
||
iterating. */
|
||
return 1;
|
||
}
|
||
|
||
/* Otherwise, we sucessfully attached to the thread. */
|
||
}
|
||
|
||
/* Construct the thread's private data. */
|
||
private = xmalloc (sizeof (struct private_thread_info));
|
||
memset (private, 0, sizeof (struct private_thread_info));
|
||
|
||
/* A thread ID of zero may mean the thread library has not initialized
|
||
yet. But we shouldn't even get here if that's the case. FIXME:
|
||
if we change GDB to always have at least one thread in the thread
|
||
list this will have to go somewhere else; maybe private == NULL
|
||
until the thread_db target claims it. */
|
||
gdb_assert (ti_p->ti_tid != 0);
|
||
private->th = *th_p;
|
||
private->tid = ti_p->ti_tid;
|
||
|
||
/* Add the thread to GDB's thread list. */
|
||
if (tp == NULL)
|
||
add_thread_with_info (ptid, private);
|
||
else
|
||
tp->private = private;
|
||
|
||
info = get_thread_db_info (GET_PID (ptid));
|
||
|
||
/* Enable thread event reporting for this thread, except when
|
||
debugging a core file. */
|
||
if (target_has_execution)
|
||
{
|
||
err = info->td_thr_event_enable_p (th_p, 1);
|
||
if (err != TD_OK)
|
||
error (_("Cannot enable thread event reporting for %s: %s"),
|
||
target_pid_to_str (ptid), thread_db_err_str (err));
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
static void
|
||
detach_thread (ptid_t ptid)
|
||
{
|
||
struct thread_info *thread_info;
|
||
|
||
/* Don't delete the thread now, because it still reports as active
|
||
until it has executed a few instructions after the event
|
||
breakpoint - if we deleted it now, "info threads" would cause us
|
||
to re-attach to it. Just mark it as having had a TD_DEATH
|
||
event. This means that we won't delete it from our thread list
|
||
until we notice that it's dead (via prune_threads), or until
|
||
something re-uses its thread ID. We'll report the thread exit
|
||
when the underlying LWP dies. */
|
||
thread_info = find_thread_ptid (ptid);
|
||
gdb_assert (thread_info != NULL && thread_info->private != NULL);
|
||
thread_info->private->dying = 1;
|
||
}
|
||
|
||
static void
|
||
thread_db_detach (struct target_ops *ops, char *args, int from_tty)
|
||
{
|
||
struct target_ops *target_beneath = find_target_beneath (ops);
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (GET_PID (inferior_ptid));
|
||
|
||
if (info)
|
||
{
|
||
if (target_has_execution)
|
||
{
|
||
disable_thread_event_reporting (info);
|
||
|
||
/* Delete the old thread event breakpoints. Note that
|
||
unlike when mourning, we can remove them here because
|
||
there's still a live inferior to poke at. In any case,
|
||
GDB will not try to insert anything in the inferior when
|
||
removing a breakpoint. */
|
||
remove_thread_event_breakpoints ();
|
||
}
|
||
|
||
delete_thread_db_info (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);
|
||
}
|
||
|
||
/* Check if PID is currently stopped at the location of a thread event
|
||
breakpoint location. If it is, read the event message and act upon
|
||
the event. */
|
||
|
||
static void
|
||
check_event (ptid_t ptid)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (ptid);
|
||
struct gdbarch *gdbarch = get_regcache_arch (regcache);
|
||
td_event_msg_t msg;
|
||
td_thrinfo_t ti;
|
||
td_err_e err;
|
||
CORE_ADDR stop_pc;
|
||
int loop = 0;
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (GET_PID (ptid));
|
||
|
||
/* Bail out early if we're not at a thread event breakpoint. */
|
||
stop_pc = regcache_read_pc (regcache)
|
||
- gdbarch_decr_pc_after_break (gdbarch);
|
||
if (stop_pc != info->td_create_bp_addr
|
||
&& stop_pc != info->td_death_bp_addr)
|
||
return;
|
||
|
||
/* Access an lwp we know is stopped. */
|
||
info->proc_handle.ptid = ptid;
|
||
|
||
/* If we have only looked at the first thread before libpthread was
|
||
initialized, we may not know its thread ID yet. Make sure we do
|
||
before we add another thread to the list. */
|
||
if (!have_threads (ptid))
|
||
thread_db_find_new_threads_1 (ptid);
|
||
|
||
/* If we are at a create breakpoint, we do not know what new lwp
|
||
was created and cannot specifically locate the event message for it.
|
||
We have to call td_ta_event_getmsg() to get
|
||
the latest message. Since we have no way of correlating whether
|
||
the event message we get back corresponds to our breakpoint, we must
|
||
loop and read all event messages, processing them appropriately.
|
||
This guarantees we will process the correct message before continuing
|
||
from the breakpoint.
|
||
|
||
Currently, death events are not enabled. If they are enabled,
|
||
the death event can use the td_thr_event_getmsg() interface to
|
||
get the message specifically for that lwp and avoid looping
|
||
below. */
|
||
|
||
loop = 1;
|
||
|
||
do
|
||
{
|
||
err = info->td_ta_event_getmsg_p (info->thread_agent, &msg);
|
||
if (err != TD_OK)
|
||
{
|
||
if (err == TD_NOMSG)
|
||
return;
|
||
|
||
error (_("Cannot get thread event message: %s"),
|
||
thread_db_err_str (err));
|
||
}
|
||
|
||
err = info->td_thr_get_info_p (msg.th_p, &ti);
|
||
if (err != TD_OK)
|
||
error (_("Cannot get thread info: %s"), thread_db_err_str (err));
|
||
|
||
ptid = ptid_build (GET_PID (ptid), ti.ti_lid, 0);
|
||
|
||
switch (msg.event)
|
||
{
|
||
case TD_CREATE:
|
||
/* Call attach_thread whether or not we already know about a
|
||
thread with this thread ID. */
|
||
attach_thread (ptid, msg.th_p, &ti);
|
||
|
||
break;
|
||
|
||
case TD_DEATH:
|
||
|
||
if (!in_thread_list (ptid))
|
||
error (_("Spurious thread death event."));
|
||
|
||
detach_thread (ptid);
|
||
|
||
break;
|
||
|
||
default:
|
||
error (_("Spurious thread event."));
|
||
}
|
||
}
|
||
while (loop);
|
||
}
|
||
|
||
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);
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
|
||
return ptid;
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXITED
|
||
|| ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
|
||
return ptid;
|
||
|
||
info = get_thread_db_info (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 (GET_PID (ptid));
|
||
if (!thread_db_list)
|
||
unpush_target (&thread_db_ops);
|
||
|
||
/* Thread event breakpoints are deleted by
|
||
update_breakpoints_after_exec. */
|
||
|
||
return ptid;
|
||
}
|
||
|
||
/* If we do not know about the main thread yet, this would be a good time to
|
||
find it. */
|
||
if (ourstatus->kind == TARGET_WAITKIND_STOPPED && !have_threads (ptid))
|
||
thread_db_find_new_threads_1 (ptid);
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_STOPPED
|
||
&& ourstatus->value.sig == TARGET_SIGNAL_TRAP)
|
||
/* Check for a thread event. */
|
||
check_event (ptid);
|
||
|
||
if (have_threads (ptid))
|
||
{
|
||
/* Change ptids back into the higher level PID + TID format. If
|
||
the thread is dead and no longer on the thread list, we will
|
||
get back a dead ptid. This can occur if the thread death
|
||
event gets postponed by other simultaneous events. In such a
|
||
case, we want to just ignore the event and continue on. */
|
||
|
||
ptid = thread_from_lwp (ptid);
|
||
if (GET_PID (ptid) == -1)
|
||
ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
|
||
}
|
||
|
||
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 (GET_PID (inferior_ptid));
|
||
|
||
target_beneath->to_mourn_inferior (target_beneath);
|
||
|
||
/* Delete the old thread event breakpoints. Do this after mourning
|
||
the inferior, so that we don't try to uninsert them. */
|
||
remove_thread_event_breakpoints ();
|
||
|
||
/* 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 = 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_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
|
||
return 0; /* A zombie -- ignore. */
|
||
|
||
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. Just enable event reporting and otherwise ignore
|
||
it. */
|
||
|
||
/* 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;
|
||
|
||
if (target_has_execution)
|
||
{
|
||
err = info->td_thr_event_enable_p (th_p, 1);
|
||
if (err != TD_OK)
|
||
error (_("Cannot enable thread event reporting for LWP %d: %s"),
|
||
(int) ti.ti_lid, thread_db_err_str (err));
|
||
}
|
||
|
||
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->private == NULL)
|
||
{
|
||
if (attach_thread (ptid, th_p, &ti))
|
||
cb_data->new_threads += 1;
|
||
else
|
||
/* Problem attaching this thread; perhaps it exited before we
|
||
could attach it?
|
||
This could mean that the thread list inside glibc itself is in
|
||
inconsistent state, and libthread_db could go on looping forever
|
||
(observed with glibc-2.3.6). To prevent that, terminate
|
||
iteration: thread_db_find_new_threads_2 will retry. */
|
||
return 1;
|
||
}
|
||
|
||
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)
|
||
{
|
||
volatile struct gdb_exception except;
|
||
struct callback_data data;
|
||
td_err_e err = TD_ERR;
|
||
|
||
data.info = info;
|
||
data.new_threads = 0;
|
||
|
||
TRY_CATCH (except, RETURN_MASK_ERROR)
|
||
{
|
||
/* 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);
|
||
}
|
||
|
||
if (libthread_db_debug)
|
||
{
|
||
if (except.reason < 0)
|
||
exception_fprintf (gdb_stderr, except,
|
||
"Warning: find_new_threads_once: ");
|
||
|
||
printf_filtered (_("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;
|
||
struct thread_db_info *info;
|
||
int pid = ptid_get_pid (ptid);
|
||
int i, loop;
|
||
|
||
info = get_thread_db_info (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; ++i, ++loop)
|
||
if (find_new_threads_once (info, i, NULL) != 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);
|
||
}
|
||
|
||
static int
|
||
update_thread_core (struct lwp_info *info, void *closure)
|
||
{
|
||
info->core = linux_nat_core_of_thread_1 (info->ptid);
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
thread_db_find_new_threads (struct target_ops *ops)
|
||
{
|
||
struct thread_db_info *info;
|
||
struct inferior *inf;
|
||
|
||
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;
|
||
|
||
thread_db_find_new_threads_1 (thread->ptid);
|
||
}
|
||
|
||
if (target_has_execution)
|
||
iterate_over_lwps (minus_one_ptid /* iterate over all */,
|
||
update_thread_core, NULL);
|
||
}
|
||
|
||
static 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->private != NULL)
|
||
{
|
||
static char buf[64];
|
||
thread_t tid;
|
||
|
||
tid = thread_info->private->tid;
|
||
snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
|
||
tid, GET_LWP (ptid));
|
||
|
||
return buf;
|
||
}
|
||
|
||
beneath = find_target_beneath (ops);
|
||
if (beneath->to_pid_to_str (beneath, ptid))
|
||
return beneath->to_pid_to_str (beneath, ptid);
|
||
|
||
return normal_pid_to_str (ptid);
|
||
}
|
||
|
||
/* Return a string describing the state of the thread specified by
|
||
INFO. */
|
||
|
||
static char *
|
||
thread_db_extra_thread_info (struct thread_info *info)
|
||
{
|
||
if (info->private == NULL)
|
||
return NULL;
|
||
|
||
if (info->private->dying)
|
||
return "Exiting";
|
||
|
||
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;
|
||
|
||
/* If we have not discovered any threads yet, check now. */
|
||
if (!have_threads (ptid))
|
||
thread_db_find_new_threads_1 (ptid);
|
||
|
||
/* Find the matching thread. */
|
||
thread_info = find_thread_ptid (ptid);
|
||
|
||
if (thread_info != NULL && thread_info->private != NULL)
|
||
{
|
||
td_err_e err;
|
||
psaddr_t address;
|
||
struct thread_db_info *info;
|
||
|
||
info = get_thread_db_info (GET_PID (ptid));
|
||
|
||
/* 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"));
|
||
|
||
/* Caller should have verified that lm != 0. */
|
||
gdb_assert (lm != 0);
|
||
|
||
/* Finally, get the address of the variable. */
|
||
/* 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 (&thread_info->private->th,
|
||
(psaddr_t)(uintptr_t) lm,
|
||
offset, &address);
|
||
|
||
#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);
|
||
if (beneath->to_get_thread_local_address)
|
||
return beneath->to_get_thread_local_address (beneath, ptid, lm, offset);
|
||
else
|
||
throw_error (TLS_GENERIC_ERROR,
|
||
_("TLS not supported on this target"));
|
||
}
|
||
|
||
/* Callback routine used to find a thread based on the TID part of
|
||
its PTID. */
|
||
|
||
static int
|
||
thread_db_find_thread_from_tid (struct thread_info *thread, void *data)
|
||
{
|
||
long *tid = (long *) data;
|
||
|
||
if (thread->private->tid == *tid)
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Implement the to_get_ada_task_ptid target method for this target. */
|
||
|
||
static ptid_t
|
||
thread_db_get_ada_task_ptid (long lwp, long thread)
|
||
{
|
||
struct thread_info *thread_info;
|
||
|
||
thread_db_find_new_threads_1 (inferior_ptid);
|
||
thread_info = iterate_over_threads (thread_db_find_thread_from_tid, &thread);
|
||
|
||
gdb_assert (thread_info != NULL);
|
||
|
||
return (thread_info->ptid);
|
||
}
|
||
|
||
static void
|
||
thread_db_resume (struct target_ops *ops,
|
||
ptid_t ptid, int step, enum target_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 (GET_PID (inferior_ptid));
|
||
else
|
||
info = get_thread_db_info (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);
|
||
}
|
||
|
||
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_find_new_threads = thread_db_find_new_threads;
|
||
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_magic = OPS_MAGIC;
|
||
}
|
||
|
||
/* Provide a prototype to silence -Wmissing-prototypes. */
|
||
extern initialize_file_ftype _initialize_thread_db;
|
||
|
||
void
|
||
_initialize_thread_db (void)
|
||
{
|
||
init_thread_db_ops ();
|
||
add_target (&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 mutiple versions of glibc,
|
||
compiled with LinuxThreads or NPTL, 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_zinteger_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 ourselves to objfile event chain. */
|
||
observer_attach_new_objfile (thread_db_new_objfile);
|
||
}
|