1200 lines
35 KiB
C
1200 lines
35 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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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 "exceptions.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-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 <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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#ifndef LIBTHREAD_DB_SO
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#define LIBTHREAD_DB_SO "libthread_db.so.1"
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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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/* 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're using this module's target vector. */
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static int using_thread_db;
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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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/* Structure that identifies the child process for the
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<proc_service.h> interface. */
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static struct ps_prochandle proc_handle;
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/* Connection to the libthread_db library. */
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static td_thragent_t *thread_agent;
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/* Pointers to the libthread_db functions. */
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static td_err_e (*td_init_p) (void);
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static td_err_e (*td_ta_new_p) (struct ps_prochandle * ps,
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td_thragent_t **ta);
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static 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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static 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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static 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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static 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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static 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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static 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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static td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th);
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static 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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static td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th,
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int event);
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static td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
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void *map_address,
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size_t offset, void **address);
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/* Location of the thread creation event breakpoint. The code at this
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location in the child process will be called by the pthread library
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whenever a new thread is created. By setting a special breakpoint
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at this location, GDB can detect when a new thread is created. We
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obtain this location via the td_ta_event_addr call. */
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static CORE_ADDR td_create_bp_addr;
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/* Location of the thread death event breakpoint. */
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static CORE_ADDR td_death_bp_addr;
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/* Prototypes for local functions. */
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static void thread_db_find_new_threads_1 (void);
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static void 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 *dummy)
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{
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return thread->private != NULL;
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}
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static int
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have_threads (void)
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{
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return iterate_over_threads (have_threads_callback, NULL) != NULL;
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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 *infop)
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{
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td_thrinfo_t ti;
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td_err_e err;
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struct thread_info *thread_info;
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ptid_t thread_ptid;
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err = 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 (GET_PID (inferior_ptid), ti.ti_lid, 0);
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thread_info = find_thread_pid (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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{
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if (infop != NULL)
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*(struct thread_info **) infop = thread_info;
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return TD_THR_ZOMBIE;
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}
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if (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 ())
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thread_db_find_new_threads_1 ();
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else
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attach_thread (thread_ptid, thp, &ti);
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thread_info = find_thread_pid (thread_ptid);
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gdb_assert (thread_info != NULL);
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}
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if (infop != NULL)
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*(struct thread_info **) infop = thread_info;
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return 0;
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}
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/* Convert between user-level thread ids and LWP ids. */
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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;
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struct thread_info *thread_info;
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ptid_t thread_ptid;
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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 (GET_LWP (ptid) != 0);
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/* Access an lwp we know is stopped. */
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proc_handle.pid = GET_LWP (ptid);
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err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &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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GET_LWP (ptid), thread_db_err_str (err));
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thread_info = NULL;
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/* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the
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event thread has already died. If another gdb interface has called
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thread_alive() previously, the thread won't be found on the thread list
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anymore. In that case, we don't want to process this ptid anymore
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to avoid the possibility of later treating it as a newly
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discovered thread id that we should add to the list. Thus,
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we return a -1 ptid which is also how the thread list marks a
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dead thread. */
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if (thread_get_info_callback (&th, &thread_info) == TD_THR_ZOMBIE
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&& thread_info == NULL)
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return pid_to_ptid (-1);
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gdb_assert (ptid_get_tid (ptid) == 0);
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return ptid;
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}
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/* Attach to lwp PTID, doing whatever else is required to have this
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LWP under the debugger's control --- e.g., enabling event
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reporting. Returns true on success. */
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int
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thread_db_attach_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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if (!using_thread_db)
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return 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 (GET_LWP (ptid) != 0);
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/* Access an lwp we know is stopped. */
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proc_handle.pid = GET_LWP (ptid);
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/* If we have only looked at the first thread before libpthread was
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initialized, we may not know its thread ID yet. Make sure we do
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before we add another thread to the list. */
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if (!have_threads ())
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thread_db_find_new_threads_1 ();
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err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &th);
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if (err != TD_OK)
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/* Cannot find user-level thread. */
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return 0;
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err = td_thr_get_info_p (&th, &ti);
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if (err != TD_OK)
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{
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warning (_("Cannot get thread info: %s"), thread_db_err_str (err));
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return 0;
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}
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attach_thread (ptid, &th, &ti);
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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"), name, dlerror ());
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return sym;
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}
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static int
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thread_db_load (void)
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{
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void *handle;
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td_err_e err;
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handle = dlopen (LIBTHREAD_DB_SO, RTLD_NOW);
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if (handle == NULL)
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{
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fprintf_filtered (gdb_stderr, "\n\ndlopen failed on '%s' - %s\n",
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LIBTHREAD_DB_SO, dlerror ());
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fprintf_filtered (gdb_stderr,
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"GDB will not be able to debug pthreads.\n\n");
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return 0;
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}
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/* Initialize pointers to the dynamic library functions we will use.
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Essential functions first. */
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td_init_p = verbose_dlsym (handle, "td_init");
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if (td_init_p == NULL)
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return 0;
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td_ta_new_p = verbose_dlsym (handle, "td_ta_new");
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if (td_ta_new_p == NULL)
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return 0;
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td_ta_map_id2thr_p = verbose_dlsym (handle, "td_ta_map_id2thr");
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if (td_ta_map_id2thr_p == NULL)
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return 0;
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td_ta_map_lwp2thr_p = verbose_dlsym (handle, "td_ta_map_lwp2thr");
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if (td_ta_map_lwp2thr_p == NULL)
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return 0;
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td_ta_thr_iter_p = verbose_dlsym (handle, "td_ta_thr_iter");
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if (td_ta_thr_iter_p == NULL)
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return 0;
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td_thr_validate_p = verbose_dlsym (handle, "td_thr_validate");
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if (td_thr_validate_p == NULL)
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return 0;
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td_thr_get_info_p = verbose_dlsym (handle, "td_thr_get_info");
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if (td_thr_get_info_p == NULL)
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return 0;
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/* Initialize the library. */
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err = td_init_p ();
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if (err != TD_OK)
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{
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warning (_("Cannot initialize libthread_db: %s"), thread_db_err_str (err));
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return 0;
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}
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/* These are not essential. */
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td_ta_event_addr_p = dlsym (handle, "td_ta_event_addr");
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td_ta_set_event_p = dlsym (handle, "td_ta_set_event");
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td_ta_event_getmsg_p = dlsym (handle, "td_ta_event_getmsg");
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td_thr_event_enable_p = dlsym (handle, "td_thr_event_enable");
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td_thr_tls_get_addr_p = dlsym (handle, "td_thr_tls_get_addr");
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return 1;
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}
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static td_err_e
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enable_thread_event (td_thragent_t *thread_agent, int event, CORE_ADDR *bp)
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{
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td_notify_t notify;
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td_err_e err;
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/* Access an lwp we know is stopped. */
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proc_handle.pid = GET_LWP (inferior_ptid);
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/* Get the breakpoint address for thread EVENT. */
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err = td_ta_event_addr_p (thread_agent, event, ¬ify);
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if (err != TD_OK)
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return err;
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/* Set up the breakpoint. */
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gdb_assert (exec_bfd);
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(*bp) = (gdbarch_convert_from_func_ptr_addr
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(current_gdbarch,
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/* Do proper sign extension for the target. */
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(bfd_get_sign_extend_vma (exec_bfd) > 0
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? (CORE_ADDR) (intptr_t) notify.u.bptaddr
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: (CORE_ADDR) (uintptr_t) notify.u.bptaddr),
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¤t_target));
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create_thread_event_breakpoint ((*bp));
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return TD_OK;
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}
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static void
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enable_thread_event_reporting (void)
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{
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td_thr_events_t events;
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td_notify_t notify;
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td_err_e err;
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#ifdef HAVE_GNU_LIBC_VERSION_H
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const char *libc_version;
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int libc_major, libc_minor;
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#endif
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/* We cannot use the thread event reporting facility if these
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functions aren't available. */
|
||
if (td_ta_event_addr_p == NULL || td_ta_set_event_p == NULL
|
||
|| td_ta_event_getmsg_p == NULL || 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 = td_ta_set_event_p (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 ();
|
||
td_create_bp_addr = 0;
|
||
td_death_bp_addr = 0;
|
||
|
||
/* Set up the thread creation event. */
|
||
err = enable_thread_event (thread_agent, TD_CREATE, &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 (thread_agent, TD_DEATH, &td_death_bp_addr);
|
||
if (err != TD_OK)
|
||
{
|
||
warning (_("Unable to get location for thread death breakpoint: %s"),
|
||
thread_db_err_str (err));
|
||
return;
|
||
}
|
||
}
|
||
|
||
static void
|
||
disable_thread_event_reporting (void)
|
||
{
|
||
td_thr_events_t events;
|
||
|
||
/* Set the process wide mask saying we aren't interested in any
|
||
events anymore. */
|
||
td_event_emptyset (&events);
|
||
td_ta_set_event_p (thread_agent, &events);
|
||
|
||
/* Delete thread event breakpoints, if any. */
|
||
remove_thread_event_breakpoints ();
|
||
td_create_bp_addr = 0;
|
||
td_death_bp_addr = 0;
|
||
}
|
||
|
||
static void
|
||
check_thread_signals (void)
|
||
{
|
||
#ifdef GET_THREAD_SIGNALS
|
||
if (!thread_signals)
|
||
{
|
||
sigset_t mask;
|
||
int i;
|
||
|
||
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;
|
||
}
|
||
}
|
||
}
|
||
#endif
|
||
}
|
||
|
||
/* 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)
|
||
{
|
||
td_err_e err;
|
||
static int already_loaded;
|
||
|
||
/* Do nothing if we couldn't load libthread_db.so.1. */
|
||
if (td_ta_new_p == NULL)
|
||
return;
|
||
|
||
/* First time through, report that libthread_db was successfuly
|
||
loaded. Can't print this in in thread_db_load as, at that stage,
|
||
the interpreter and it's console haven't started. */
|
||
|
||
if (!already_loaded)
|
||
{
|
||
Dl_info info;
|
||
const char *library = NULL;
|
||
if (dladdr ((*td_ta_new_p), &info) != 0)
|
||
library = info.dli_fname;
|
||
|
||
/* Try dlinfo? */
|
||
|
||
if (library == NULL)
|
||
/* Paranoid - don't let a NULL path slip through. */
|
||
library = LIBTHREAD_DB_SO;
|
||
|
||
if (info_verbose)
|
||
printf_unfiltered (_("Using host libthread_db library \"%s\".\n"),
|
||
library);
|
||
already_loaded = 1;
|
||
}
|
||
|
||
if (using_thread_db)
|
||
/* Nothing to do. The thread library was already detected and the
|
||
target vector was already activated. */
|
||
return;
|
||
|
||
/* Don't attempt to use thread_db on targets which can not run
|
||
(executables not running yet, core files) for now. */
|
||
if (!target_has_execution)
|
||
return;
|
||
|
||
/* Don't attempt to use thread_db for remote targets. */
|
||
if (!target_can_run (¤t_target))
|
||
return;
|
||
|
||
/* Initialize the structure that identifies the child process. */
|
||
proc_handle.pid = GET_PID (inferior_ptid);
|
||
|
||
/* Now attempt to open a connection to the thread library. */
|
||
err = td_ta_new_p (&proc_handle, &thread_agent);
|
||
switch (err)
|
||
{
|
||
case TD_NOLIBTHREAD:
|
||
/* No thread library was detected. */
|
||
break;
|
||
|
||
case TD_OK:
|
||
printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
|
||
|
||
/* The thread library was detected. Activate the thread_db target. */
|
||
push_target (&thread_db_ops);
|
||
using_thread_db = 1;
|
||
|
||
enable_thread_event_reporting ();
|
||
thread_db_find_new_threads_1 ();
|
||
break;
|
||
|
||
default:
|
||
warning (_("Cannot initialize thread debugging library: %s"),
|
||
thread_db_err_str (err));
|
||
break;
|
||
}
|
||
}
|
||
|
||
static void
|
||
thread_db_new_objfile (struct objfile *objfile)
|
||
{
|
||
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. */
|
||
|
||
static void
|
||
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;
|
||
|
||
/* 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_pid (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;
|
||
|
||
delete_thread (ptid);
|
||
tp = NULL;
|
||
}
|
||
}
|
||
|
||
check_thread_signals ();
|
||
|
||
if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
|
||
return; /* A zombie thread -- do not attach. */
|
||
|
||
/* Under GNU/Linux, we have to attach to each and every thread. */
|
||
if (tp == NULL
|
||
&& lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid))) < 0)
|
||
return;
|
||
|
||
/* 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)
|
||
tp = add_thread_with_info (ptid, private);
|
||
else
|
||
tp->private = private;
|
||
|
||
/* Enable thread event reporting for this thread. */
|
||
err = 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));
|
||
}
|
||
|
||
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_pid (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);
|
||
|
||
disable_thread_event_reporting ();
|
||
|
||
/* Forget about the child's process ID. We shouldn't need it
|
||
anymore. */
|
||
proc_handle.pid = 0;
|
||
|
||
/* Detach thread_db target ops. */
|
||
unpush_target (&thread_db_ops);
|
||
using_thread_db = 0;
|
||
|
||
target_beneath->to_detach (target_beneath, args, from_tty);
|
||
}
|
||
|
||
/* 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;
|
||
|
||
/* 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 != td_create_bp_addr && stop_pc != td_death_bp_addr)
|
||
return;
|
||
|
||
/* Access an lwp we know is stopped. */
|
||
proc_handle.pid = GET_LWP (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 ())
|
||
thread_db_find_new_threads_1 ();
|
||
|
||
/* 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 = td_ta_event_getmsg_p (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 = 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)
|
||
{
|
||
struct target_ops *beneath = find_target_beneath (ops);
|
||
|
||
ptid = beneath->to_wait (beneath, ptid, ourstatus);
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
|
||
return ptid;
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXITED
|
||
|| ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
|
||
return ptid;
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXECD)
|
||
{
|
||
remove_thread_event_breakpoints ();
|
||
unpush_target (&thread_db_ops);
|
||
using_thread_db = 0;
|
||
|
||
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 ())
|
||
thread_db_find_new_threads_1 ();
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_STOPPED
|
||
&& ourstatus->value.sig == TARGET_SIGNAL_TRAP)
|
||
/* Check for a thread event. */
|
||
check_event (ptid);
|
||
|
||
if (have_threads ())
|
||
{
|
||
/* 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);
|
||
|
||
/* Forget about the child's process ID. We shouldn't need it
|
||
anymore. */
|
||
proc_handle.pid = 0;
|
||
|
||
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. */
|
||
unpush_target (ops);
|
||
using_thread_db = 0;
|
||
}
|
||
|
||
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;
|
||
|
||
err = 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. */
|
||
|
||
ptid = ptid_build (GET_PID (inferior_ptid), ti.ti_lid, 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. Just enable event reporting and otherwise ignore
|
||
it. */
|
||
|
||
err = 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 0;
|
||
}
|
||
|
||
tp = find_thread_pid (ptid);
|
||
if (tp == NULL || tp->private == NULL)
|
||
attach_thread (ptid, th_p, &ti);
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Search for new threads, accessing memory through stopped thread
|
||
PTID. */
|
||
|
||
static void
|
||
thread_db_find_new_threads_1 (void)
|
||
{
|
||
td_err_e err;
|
||
struct lwp_info *lp;
|
||
ptid_t ptid;
|
||
|
||
/* In linux, we can only read memory through a stopped lwp. */
|
||
ALL_LWPS (lp, ptid)
|
||
if (lp->stopped)
|
||
break;
|
||
|
||
if (!lp)
|
||
/* There is no stopped thread. Bail out. */
|
||
return;
|
||
|
||
/* Access an lwp we know is stopped. */
|
||
proc_handle.pid = GET_LWP (ptid);
|
||
/* Iterate over all user-space threads to discover new threads. */
|
||
err = td_ta_thr_iter_p (thread_agent, find_new_threads_callback, NULL,
|
||
TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
|
||
TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
|
||
if (err != TD_OK)
|
||
error (_("Cannot find new threads: %s"), thread_db_err_str (err));
|
||
}
|
||
|
||
static void
|
||
thread_db_find_new_threads (struct target_ops *ops)
|
||
{
|
||
thread_db_find_new_threads_1 ();
|
||
}
|
||
|
||
static char *
|
||
thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid)
|
||
{
|
||
struct thread_info *thread_info = find_thread_pid (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;
|
||
thread_info = find_thread_pid (ptid);
|
||
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 ())
|
||
thread_db_find_new_threads_1 ();
|
||
|
||
/* Find the matching thread. */
|
||
thread_info = find_thread_pid (ptid);
|
||
|
||
if (thread_info != NULL && thread_info->private != NULL)
|
||
{
|
||
td_err_e err;
|
||
void *address;
|
||
|
||
/* glibc doesn't provide the needed interface. */
|
||
if (!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. */
|
||
err = td_thr_tls_get_addr_p (&thread_info->private->th,
|
||
(void *)(size_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 ();
|
||
thread_info = iterate_over_threads (thread_db_find_thread_from_tid, &thread);
|
||
|
||
gdb_assert (thread_info != NULL);
|
||
|
||
return (thread_info->ptid);
|
||
}
|
||
|
||
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_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)
|
||
{
|
||
/* Only initialize the module if we can load libthread_db. */
|
||
if (thread_db_load ())
|
||
{
|
||
init_thread_db_ops ();
|
||
add_target (&thread_db_ops);
|
||
|
||
/* Add ourselves to objfile event chain. */
|
||
observer_attach_new_objfile (thread_db_new_objfile);
|
||
}
|
||
}
|