1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "gdb_proc_service.h"
23 #include "nat/gdb_thread_db.h"
28 #include "gdbthread.h"
36 #include "solib-svr4.h"
39 #include "linux-nat.h"
40 #include "nat/linux-procfs.h"
41 #include "nat/linux-ptrace.h"
42 #include "nat/linux-osdata.h"
43 #include "auto-load.h"
44 #include "cli/cli-utils.h"
49 /* GNU/Linux libthread_db support.
51 libthread_db is a library, provided along with libpthread.so, which
52 exposes the internals of the thread library to a debugger. It
53 allows GDB to find existing threads, new threads as they are
54 created, thread IDs (usually, the result of pthread_self), and
55 thread-local variables.
57 The libthread_db interface originates on Solaris, where it is
58 both more powerful and more complicated. This implementation
59 only works for LinuxThreads and NPTL, the two glibc threading
60 libraries. It assumes that each thread is permanently assigned
61 to a single light-weight process (LWP).
63 libthread_db-specific information is stored in the "private" field
64 of struct thread_info. When the field is NULL we do not yet have
65 information about the new thread; this could be temporary (created,
66 but the thread library's data structures do not reflect it yet)
67 or permanent (created using clone instead of pthread_create).
69 Process IDs managed by linux-thread-db.c match those used by
70 linux-nat.c: a common PID for all processes, an LWP ID for each
71 thread, and no TID. We save the TID in private. Keeping it out
72 of the ptid_t prevents thread IDs changing when libpthread is
73 loaded or unloaded. */
75 static char *libthread_db_search_path
;
77 /* Set to non-zero if thread_db auto-loading is enabled
78 by the "set auto-load libthread-db" command. */
79 static int auto_load_thread_db
= 1;
81 /* Returns true if we need to use thread_db thread create/death event
82 breakpoints to learn about threads. */
85 thread_db_use_events (void)
87 /* Not necessary if the kernel supports clone events. */
88 return !linux_supports_traceclone ();
91 /* "show" command for the auto_load_thread_db configuration variable. */
94 show_auto_load_thread_db (struct ui_file
*file
, int from_tty
,
95 struct cmd_list_element
*c
, const char *value
)
97 fprintf_filtered (file
, _("Auto-loading of inferior specific libthread_db "
103 set_libthread_db_search_path (char *ignored
, int from_tty
,
104 struct cmd_list_element
*c
)
106 if (*libthread_db_search_path
== '\0')
108 xfree (libthread_db_search_path
);
109 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
113 /* If non-zero, print details of libthread_db processing. */
115 static unsigned int libthread_db_debug
;
118 show_libthread_db_debug (struct ui_file
*file
, int from_tty
,
119 struct cmd_list_element
*c
, const char *value
)
121 fprintf_filtered (file
, _("libthread-db debugging is %s.\n"), value
);
124 /* If we're running on GNU/Linux, we must explicitly attach to any new
127 /* This module's target vector. */
128 static struct target_ops thread_db_ops
;
130 /* Non-zero if we have determined the signals used by the threads
132 static int thread_signals
;
133 static sigset_t thread_stop_set
;
134 static sigset_t thread_print_set
;
136 struct thread_db_info
138 struct thread_db_info
*next
;
140 /* Process id this object refers to. */
143 /* Handle from dlopen for libthread_db.so. */
146 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
147 HANDLE. It may be NULL for system library. */
150 /* Structure that identifies the child process for the
151 <proc_service.h> interface. */
152 struct ps_prochandle proc_handle
;
154 /* Connection to the libthread_db library. */
155 td_thragent_t
*thread_agent
;
157 /* True if we need to apply the workaround for glibc/BZ5983. When
158 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
159 list, nptl_db returns the parent's threads in addition to the new
160 (single) child thread. If this flag is set, we do extra work to
161 be able to ignore such stale entries. */
162 int need_stale_parent_threads_check
;
164 /* Location of the thread creation event breakpoint. The code at
165 this location in the child process will be called by the pthread
166 library whenever a new thread is created. By setting a special
167 breakpoint at this location, GDB can detect when a new thread is
168 created. We obtain this location via the td_ta_event_addr
170 CORE_ADDR td_create_bp_addr
;
172 /* Location of the thread death event breakpoint. */
173 CORE_ADDR td_death_bp_addr
;
175 /* Pointers to the libthread_db functions. */
177 td_err_e (*td_init_p
) (void);
179 td_err_e (*td_ta_new_p
) (struct ps_prochandle
* ps
,
181 td_err_e (*td_ta_map_id2thr_p
) (const td_thragent_t
*ta
, thread_t pt
,
182 td_thrhandle_t
*__th
);
183 td_err_e (*td_ta_map_lwp2thr_p
) (const td_thragent_t
*ta
,
184 lwpid_t lwpid
, td_thrhandle_t
*th
);
185 td_err_e (*td_ta_thr_iter_p
) (const td_thragent_t
*ta
,
186 td_thr_iter_f
*callback
, void *cbdata_p
,
187 td_thr_state_e state
, int ti_pri
,
188 sigset_t
*ti_sigmask_p
,
189 unsigned int ti_user_flags
);
190 td_err_e (*td_ta_event_addr_p
) (const td_thragent_t
*ta
,
191 td_event_e event
, td_notify_t
*ptr
);
192 td_err_e (*td_ta_set_event_p
) (const td_thragent_t
*ta
,
193 td_thr_events_t
*event
);
194 td_err_e (*td_ta_clear_event_p
) (const td_thragent_t
*ta
,
195 td_thr_events_t
*event
);
196 td_err_e (*td_ta_event_getmsg_p
) (const td_thragent_t
*ta
,
197 td_event_msg_t
*msg
);
199 td_err_e (*td_thr_validate_p
) (const td_thrhandle_t
*th
);
200 td_err_e (*td_thr_get_info_p
) (const td_thrhandle_t
*th
,
201 td_thrinfo_t
*infop
);
202 td_err_e (*td_thr_event_enable_p
) (const td_thrhandle_t
*th
,
205 td_err_e (*td_thr_tls_get_addr_p
) (const td_thrhandle_t
*th
,
206 psaddr_t map_address
,
207 size_t offset
, psaddr_t
*address
);
208 td_err_e (*td_thr_tlsbase_p
) (const td_thrhandle_t
*th
,
209 unsigned long int modid
,
213 /* List of known processes using thread_db, and the required
215 struct thread_db_info
*thread_db_list
;
217 static void thread_db_find_new_threads_1 (ptid_t ptid
);
218 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
220 static void check_thread_signals (void);
222 static void record_thread (struct thread_db_info
*info
,
223 struct thread_info
*tp
,
224 ptid_t ptid
, const td_thrhandle_t
*th_p
,
225 const td_thrinfo_t
*ti_p
);
227 /* Add the current inferior to the list of processes using libpthread.
228 Return a pointer to the newly allocated object that was added to
229 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
232 static struct thread_db_info
*
233 add_thread_db_info (void *handle
)
235 struct thread_db_info
*info
;
237 info
= xcalloc (1, sizeof (*info
));
238 info
->pid
= ptid_get_pid (inferior_ptid
);
239 info
->handle
= handle
;
241 /* The workaround works by reading from /proc/pid/status, so it is
242 disabled for core files. */
243 if (target_has_execution
)
244 info
->need_stale_parent_threads_check
= 1;
246 info
->next
= thread_db_list
;
247 thread_db_list
= info
;
252 /* Return the thread_db_info object representing the bookkeeping
253 related to process PID, if any; NULL otherwise. */
255 static struct thread_db_info
*
256 get_thread_db_info (int pid
)
258 struct thread_db_info
*info
;
260 for (info
= thread_db_list
; info
; info
= info
->next
)
261 if (pid
== info
->pid
)
267 /* When PID has exited or has been detached, we no longer want to keep
268 track of it as using libpthread. Call this function to discard
269 thread_db related info related to PID. Note that this closes
270 LIBTHREAD_DB_SO's dlopen'ed handle. */
273 delete_thread_db_info (int pid
)
275 struct thread_db_info
*info
, *info_prev
;
279 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
280 if (pid
== info
->pid
)
286 if (info
->handle
!= NULL
)
287 dlclose (info
->handle
);
289 xfree (info
->filename
);
292 info_prev
->next
= info
->next
;
294 thread_db_list
= info
->next
;
299 /* Prototypes for local functions. */
300 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
301 const td_thrinfo_t
*ti_p
);
302 static void detach_thread (ptid_t ptid
);
305 /* Use "struct private_thread_info" to cache thread state. This is
306 a substantial optimization. */
308 struct private_thread_info
310 /* Flag set when we see a TD_DEATH event for this thread. */
311 unsigned int dying
:1;
313 /* Cached thread state. */
320 thread_db_err_str (td_err_e err
)
327 return "generic 'call succeeded'";
329 return "generic error";
331 return "no thread to satisfy query";
333 return "no sync handle to satisfy query";
335 return "no LWP to satisfy query";
337 return "invalid process handle";
339 return "invalid thread handle";
341 return "invalid synchronization handle";
343 return "invalid thread agent";
345 return "invalid key";
347 return "no event message for getmsg";
349 return "FPU register set not available";
351 return "application not linked with libthread";
353 return "requested event is not supported";
355 return "capability not available";
357 return "debugger service failed";
359 return "operation not applicable to";
361 return "no thread-specific data for this thread";
363 return "malloc failed";
365 return "only part of register set was written/read";
367 return "X register set not available for this thread";
368 #ifdef THREAD_DB_HAS_TD_NOTALLOC
370 return "thread has not yet allocated TLS for given module";
372 #ifdef THREAD_DB_HAS_TD_VERSION
374 return "versions of libpthread and libthread_db do not match";
376 #ifdef THREAD_DB_HAS_TD_NOTLS
378 return "there is no TLS segment in the given module";
381 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
386 /* Return 1 if any threads have been registered. There may be none if
387 the threading library is not fully initialized yet. */
390 have_threads_callback (struct thread_info
*thread
, void *args
)
392 int pid
= * (int *) args
;
394 if (ptid_get_pid (thread
->ptid
) != pid
)
397 return thread
->priv
!= NULL
;
401 have_threads (ptid_t ptid
)
403 int pid
= ptid_get_pid (ptid
);
405 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
409 /* Fetch the user-level thread id of PTID. */
412 thread_from_lwp (ptid_t ptid
)
417 struct thread_db_info
*info
;
418 struct thread_info
*tp
;
420 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
423 /* This ptid comes from linux-nat.c, which should always fill in the
425 gdb_assert (ptid_get_lwp (ptid
) != 0);
427 info
= get_thread_db_info (ptid_get_pid (ptid
));
429 /* Access an lwp we know is stopped. */
430 info
->proc_handle
.ptid
= ptid
;
431 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
434 error (_("Cannot find user-level thread for LWP %ld: %s"),
435 ptid_get_lwp (ptid
), thread_db_err_str (err
));
437 err
= info
->td_thr_get_info_p (&th
, &ti
);
439 error (_("thread_get_info_callback: cannot get thread info: %s"),
440 thread_db_err_str (err
));
442 /* Fill the cache. */
443 tp
= find_thread_ptid (ptid
);
444 record_thread (info
, tp
, ptid
, &th
, &ti
);
448 /* See linux-nat.h. */
451 thread_db_notice_clone (ptid_t parent
, ptid_t child
)
456 struct thread_db_info
*info
;
458 info
= get_thread_db_info (ptid_get_pid (child
));
463 thread_from_lwp (child
);
465 /* If we do not know about the main thread yet, this would be a good
467 thread_from_lwp (parent
);
472 verbose_dlsym (void *handle
, const char *name
)
474 void *sym
= dlsym (handle
, name
);
476 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
482 enable_thread_event (int event
, CORE_ADDR
*bp
)
486 struct thread_db_info
*info
;
488 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
490 /* Access an lwp we know is stopped. */
491 info
->proc_handle
.ptid
= inferior_ptid
;
493 /* Get the breakpoint address for thread EVENT. */
494 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
498 /* Set up the breakpoint. */
499 gdb_assert (exec_bfd
);
500 (*bp
) = (gdbarch_convert_from_func_ptr_addr
502 /* Do proper sign extension for the target. */
503 (bfd_get_sign_extend_vma (exec_bfd
) > 0
504 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
505 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
507 create_thread_event_breakpoint (target_gdbarch (), *bp
);
512 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
513 return 1 if this version is lower (and not equal) to
514 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
517 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
519 struct bound_minimal_symbol version_msym
;
520 CORE_ADDR version_addr
;
522 int err
, got
, retval
= 0;
524 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
525 if (version_msym
.minsym
== NULL
)
528 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
529 got
= target_read_string (version_addr
, &version
, 32, &err
);
530 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
534 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
535 && (major
< ver_major_min
536 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
544 enable_thread_event_reporting (void)
546 td_thr_events_t events
;
548 struct thread_db_info
*info
;
550 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
552 /* We cannot use the thread event reporting facility if these
553 functions aren't available. */
554 if (info
->td_ta_event_addr_p
== NULL
555 || info
->td_ta_set_event_p
== NULL
556 || info
->td_ta_event_getmsg_p
== NULL
557 || info
->td_thr_event_enable_p
== NULL
)
560 /* Set the process wide mask saying which events we're interested in. */
561 td_event_emptyset (&events
);
562 td_event_addset (&events
, TD_CREATE
);
564 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
565 commit 2e4581e4fba917f1779cd0a010a45698586c190a
566 * manager.c (pthread_exited): Correctly report event as TD_REAP
567 instead of TD_DEATH. Fix comments.
568 where event reporting facility is broken for TD_DEATH events,
569 so don't enable it if we have glibc but a lower version. */
570 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
571 td_event_addset (&events
, TD_DEATH
);
573 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
576 warning (_("Unable to set global thread event mask: %s"),
577 thread_db_err_str (err
));
581 /* Delete previous thread event breakpoints, if any. */
582 remove_thread_event_breakpoints ();
583 info
->td_create_bp_addr
= 0;
584 info
->td_death_bp_addr
= 0;
586 /* Set up the thread creation event. */
587 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
590 warning (_("Unable to get location for thread creation breakpoint: %s"),
591 thread_db_err_str (err
));
595 /* Set up the thread death event. */
596 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
599 warning (_("Unable to get location for thread death breakpoint: %s"),
600 thread_db_err_str (err
));
605 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
608 Return 1 if the caller should abort libthread_db initialization. Return 0
612 thread_db_find_new_threads_silently (ptid_t ptid
)
617 thread_db_find_new_threads_2 (ptid
, 1);
620 CATCH (except
, RETURN_MASK_ERROR
)
622 if (libthread_db_debug
)
623 exception_fprintf (gdb_stdlog
, except
,
624 "Warning: thread_db_find_new_threads_silently: ");
626 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
627 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
628 where calls to td_thr_get_info fail with TD_ERR for statically linked
629 executables if td_thr_get_info is called before glibc has initialized
632 If the nptl bug is NOT present in the inferior and still thread_db
633 reports an error return 1. It means the inferior has corrupted thread
634 list and GDB should fall back only to LWPs.
636 If the nptl bug is present in the inferior return 0 to silently ignore
637 such errors, and let gdb enumerate threads again later. In such case
638 GDB cannot properly display LWPs if the inferior thread list is
639 corrupted. For core files it does not apply, no 'later enumeration'
642 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
644 exception_fprintf (gdb_stderr
, except
,
645 _("Warning: couldn't activate thread debugging "
646 "using libthread_db: "));
655 /* Lookup a library in which given symbol resides.
656 Note: this is looking in GDB process, not in the inferior.
657 Returns library name, or NULL. */
660 dladdr_to_soname (const void *addr
)
664 if (dladdr (addr
, &info
) != 0)
665 return info
.dli_fname
;
669 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
671 Failure could happen if libthread_db does not have symbols we expect,
672 or when it refuses to work with the current inferior (e.g. due to
673 version mismatch between libthread_db and libpthread). */
676 try_thread_db_load_1 (struct thread_db_info
*info
)
680 /* Initialize pointers to the dynamic library functions we will use.
681 Essential functions first. */
683 info
->td_init_p
= verbose_dlsym (info
->handle
, "td_init");
684 if (info
->td_init_p
== NULL
)
687 err
= info
->td_init_p ();
690 warning (_("Cannot initialize libthread_db: %s"),
691 thread_db_err_str (err
));
695 info
->td_ta_new_p
= verbose_dlsym (info
->handle
, "td_ta_new");
696 if (info
->td_ta_new_p
== NULL
)
699 /* Initialize the structure that identifies the child process. */
700 info
->proc_handle
.ptid
= inferior_ptid
;
702 /* Now attempt to open a connection to the thread library. */
703 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
706 if (libthread_db_debug
)
707 fprintf_unfiltered (gdb_stdlog
, _("td_ta_new failed: %s\n"),
708 thread_db_err_str (err
));
713 #ifdef THREAD_DB_HAS_TD_VERSION
716 /* The errors above are not unexpected and silently ignored:
717 they just mean we haven't found correct version of
721 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
726 info
->td_ta_map_id2thr_p
= verbose_dlsym (info
->handle
, "td_ta_map_id2thr");
727 if (info
->td_ta_map_id2thr_p
== NULL
)
730 info
->td_ta_map_lwp2thr_p
= verbose_dlsym (info
->handle
,
731 "td_ta_map_lwp2thr");
732 if (info
->td_ta_map_lwp2thr_p
== NULL
)
735 info
->td_ta_thr_iter_p
= verbose_dlsym (info
->handle
, "td_ta_thr_iter");
736 if (info
->td_ta_thr_iter_p
== NULL
)
739 info
->td_thr_validate_p
= verbose_dlsym (info
->handle
, "td_thr_validate");
740 if (info
->td_thr_validate_p
== NULL
)
743 info
->td_thr_get_info_p
= verbose_dlsym (info
->handle
, "td_thr_get_info");
744 if (info
->td_thr_get_info_p
== NULL
)
747 /* These are not essential. */
748 info
->td_ta_event_addr_p
= dlsym (info
->handle
, "td_ta_event_addr");
749 info
->td_ta_set_event_p
= dlsym (info
->handle
, "td_ta_set_event");
750 info
->td_ta_clear_event_p
= dlsym (info
->handle
, "td_ta_clear_event");
751 info
->td_ta_event_getmsg_p
= dlsym (info
->handle
, "td_ta_event_getmsg");
752 info
->td_thr_event_enable_p
= dlsym (info
->handle
, "td_thr_event_enable");
753 info
->td_thr_tls_get_addr_p
= dlsym (info
->handle
, "td_thr_tls_get_addr");
754 info
->td_thr_tlsbase_p
= dlsym (info
->handle
, "td_thr_tlsbase");
756 /* It's best to avoid td_ta_thr_iter if possible. That walks data
757 structures in the inferior's address space that may be corrupted,
758 or, if the target is running, may change while we walk them. If
759 there's execution (and /proc is mounted), then we're already
760 attached to all LWPs. Use thread_from_lwp, which uses
761 td_ta_map_lwp2thr instead, which does not walk the thread list.
763 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
764 currently on core targets, as it uses ptrace directly. */
765 if (target_has_execution
766 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid
)))
769 int pid
= ptid_get_pid (inferior_ptid
);
771 linux_stop_and_wait_all_lwps ();
774 if (ptid_get_pid (lp
->ptid
) == pid
)
775 thread_from_lwp (lp
->ptid
);
777 linux_unstop_all_lwps ();
779 else if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
781 /* Even if libthread_db initializes, if the thread list is
782 corrupted, we'd not manage to list any threads. Better reject this
783 thread_db, and fall back to at least listing LWPs. */
787 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
789 if (*libthread_db_search_path
|| libthread_db_debug
)
791 struct ui_file
*file
;
794 library
= dladdr_to_soname (*info
->td_ta_new_p
);
796 library
= LIBTHREAD_DB_SO
;
798 /* If we'd print this to gdb_stdout when debug output is
799 disabled, still print it to gdb_stdout if debug output is
800 enabled. User visible output should not depend on debug
802 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
803 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
807 /* The thread library was detected. Activate the thread_db target
808 if this is the first process using it. */
809 if (thread_db_list
->next
== NULL
)
810 push_target (&thread_db_ops
);
812 /* Enable event reporting, but not when debugging a core file. */
813 if (target_has_execution
&& thread_db_use_events ())
814 enable_thread_event_reporting ();
819 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
820 relative, or just LIBTHREAD_DB. */
823 try_thread_db_load (const char *library
, int check_auto_load_safe
)
826 struct thread_db_info
*info
;
828 if (libthread_db_debug
)
829 fprintf_unfiltered (gdb_stdlog
,
830 _("Trying host libthread_db library: %s.\n"),
833 if (check_auto_load_safe
)
835 if (access (library
, R_OK
) != 0)
837 /* Do not print warnings by file_is_auto_load_safe if the library does
838 not exist at this place. */
839 if (libthread_db_debug
)
840 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
841 safe_strerror (errno
));
845 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
846 "library \"%s\" from explicit "
852 handle
= dlopen (library
, RTLD_NOW
);
855 if (libthread_db_debug
)
856 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
860 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
864 td_init
= dlsym (handle
, "td_init");
867 const char *const libpath
= dladdr_to_soname (td_init
);
870 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
875 info
= add_thread_db_info (handle
);
877 /* Do not save system library name, that one is always trusted. */
878 if (strchr (library
, '/') != NULL
)
879 info
->filename
= gdb_realpath (library
);
881 if (try_thread_db_load_1 (info
))
884 /* This library "refused" to work on current inferior. */
885 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
889 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
890 Try loading libthread_db in directory(OBJ)/SUBDIR.
891 SUBDIR may be NULL. It may also be something like "../lib64".
892 The result is true for success. */
895 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
897 struct cleanup
*cleanup
;
900 const char *obj_name
= objfile_name (obj
);
902 if (obj_name
[0] != '/')
904 warning (_("Expected absolute pathname for libpthread in the"
905 " inferior, but got %s."), obj_name
);
909 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
910 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
911 cleanup
= make_cleanup (xfree
, path
);
913 strcpy (path
, obj_name
);
914 cp
= strrchr (path
, '/');
915 /* This should at minimum hit the first character. */
916 gdb_assert (cp
!= NULL
);
923 strcat (cp
, LIBTHREAD_DB_SO
);
925 result
= try_thread_db_load (path
, 1);
927 do_cleanups (cleanup
);
931 /* Handle $pdir in libthread-db-search-path.
932 Look for libthread_db in directory(libpthread)/SUBDIR.
933 SUBDIR may be NULL. It may also be something like "../lib64".
934 The result is true for success. */
937 try_thread_db_load_from_pdir (const char *subdir
)
941 if (!auto_load_thread_db
)
945 if (libpthread_name_p (objfile_name (obj
)))
947 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
950 /* We may have found the separate-debug-info version of
951 libpthread, and it may live in a directory without a matching
953 if (obj
->separate_debug_objfile_backlink
!= NULL
)
954 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
963 /* Handle $sdir in libthread-db-search-path.
964 Look for libthread_db in the system dirs, or wherever a plain
965 dlopen(file_without_path) will look.
966 The result is true for success. */
969 try_thread_db_load_from_sdir (void)
971 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
974 /* Try to load libthread_db from directory DIR of length DIR_LEN.
975 The result is true for success. */
978 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
980 struct cleanup
*cleanup
;
984 if (!auto_load_thread_db
)
987 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
988 cleanup
= make_cleanup (xfree
, path
);
990 memcpy (path
, dir
, dir_len
);
992 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
994 result
= try_thread_db_load (path
, 1);
996 do_cleanups (cleanup
);
1000 /* Search libthread_db_search_path for libthread_db which "agrees"
1001 to work on current inferior.
1002 The result is true for success. */
1005 thread_db_load_search (void)
1007 VEC (char_ptr
) *dir_vec
;
1008 struct cleanup
*cleanups
;
1012 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
1013 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
1015 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
1017 const int pdir_len
= sizeof ("$pdir") - 1;
1018 size_t this_dir_len
;
1020 this_dir_len
= strlen (this_dir
);
1022 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
1023 && (this_dir
[pdir_len
] == '\0'
1024 || this_dir
[pdir_len
] == '/'))
1026 char *subdir
= NULL
;
1027 struct cleanup
*free_subdir_cleanup
1028 = make_cleanup (null_cleanup
, NULL
);
1030 if (this_dir
[pdir_len
] == '/')
1032 subdir
= xmalloc (strlen (this_dir
));
1033 make_cleanup (xfree
, subdir
);
1034 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1036 rc
= try_thread_db_load_from_pdir (subdir
);
1037 do_cleanups (free_subdir_cleanup
);
1041 else if (strcmp (this_dir
, "$sdir") == 0)
1043 if (try_thread_db_load_from_sdir ())
1051 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1059 do_cleanups (cleanups
);
1060 if (libthread_db_debug
)
1061 fprintf_unfiltered (gdb_stdlog
,
1062 _("thread_db_load_search returning %d\n"), rc
);
1066 /* Return non-zero if the inferior has a libpthread. */
1069 has_libpthread (void)
1071 struct objfile
*obj
;
1074 if (libpthread_name_p (objfile_name (obj
)))
1080 /* Attempt to load and initialize libthread_db.
1081 Return 1 on success. */
1084 thread_db_load (void)
1086 struct thread_db_info
*info
;
1088 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1093 /* Don't attempt to use thread_db on executables not running
1095 if (!target_has_registers
)
1098 /* Don't attempt to use thread_db for remote targets. */
1099 if (!(target_can_run (¤t_target
) || core_bfd
))
1102 if (thread_db_load_search ())
1105 /* We couldn't find a libthread_db.
1106 If the inferior has a libpthread warn the user. */
1107 if (has_libpthread ())
1109 warning (_("Unable to find libthread_db matching inferior's thread"
1110 " library, thread debugging will not be available."));
1114 /* Either this executable isn't using libpthread at all, or it is
1115 statically linked. Since we can't easily distinguish these two cases,
1116 no warning is issued. */
1121 disable_thread_event_reporting (struct thread_db_info
*info
)
1123 if (info
->td_ta_clear_event_p
!= NULL
)
1125 td_thr_events_t events
;
1127 /* Set the process wide mask saying we aren't interested in any
1129 td_event_fillset (&events
);
1130 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1133 info
->td_create_bp_addr
= 0;
1134 info
->td_death_bp_addr
= 0;
1138 check_thread_signals (void)
1140 if (!thread_signals
)
1145 lin_thread_get_thread_signals (&mask
);
1146 sigemptyset (&thread_stop_set
);
1147 sigemptyset (&thread_print_set
);
1149 for (i
= 1; i
< NSIG
; i
++)
1151 if (sigismember (&mask
, i
))
1153 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1154 sigaddset (&thread_stop_set
, i
);
1155 if (signal_print_update (gdb_signal_from_host (i
), 0))
1156 sigaddset (&thread_print_set
, i
);
1163 /* Check whether thread_db is usable. This function is called when
1164 an inferior is created (or otherwise acquired, e.g. attached to)
1165 and when new shared libraries are loaded into a running process. */
1168 check_for_thread_db (void)
1170 /* Do nothing if we couldn't load libthread_db.so.1. */
1171 if (!thread_db_load ())
1175 /* This function is called via the new_objfile observer. */
1178 thread_db_new_objfile (struct objfile
*objfile
)
1180 /* This observer must always be called with inferior_ptid set
1184 /* libpthread with separate debug info has its debug info file already
1185 loaded (and notified without successful thread_db initialization)
1186 the time observer_notify_new_objfile is called for the library itself.
1187 Static executables have their separate debug info loaded already
1188 before the inferior has started. */
1189 && objfile
->separate_debug_objfile_backlink
== NULL
1190 /* Only check for thread_db if we loaded libpthread,
1191 or if this is the main symbol file.
1192 We need to check OBJF_MAINLINE to handle the case of debugging
1193 a statically linked executable AND the symbol file is specified AFTER
1194 the exec file is loaded (e.g., gdb -c core ; file foo).
1195 For dynamically linked executables, libpthread can be near the end
1196 of the list of shared libraries to load, and in an app of several
1197 thousand shared libraries, this can otherwise be painful. */
1198 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1199 || libpthread_name_p (objfile_name (objfile
))))
1200 check_for_thread_db ();
1204 check_pid_namespace_match (void)
1206 /* Check is only relevant for local targets targets. */
1207 if (target_can_run (¤t_target
))
1209 /* If the child is in a different PID namespace, its idea of its
1210 PID will differ from our idea of its PID. When we scan the
1211 child's thread list, we'll mistakenly think it has no threads
1212 since the thread PID fields won't match the PID we give to
1214 char *our_pid_ns
= linux_proc_pid_get_ns (getpid (), "pid");
1215 char *inferior_pid_ns
= linux_proc_pid_get_ns (
1216 ptid_get_pid (inferior_ptid
), "pid");
1218 if (our_pid_ns
!= NULL
&& inferior_pid_ns
!= NULL
1219 && strcmp (our_pid_ns
, inferior_pid_ns
) != 0)
1221 warning (_ ("Target and debugger are in different PID "
1222 "namespaces; thread lists and other data are "
1223 "likely unreliable"));
1227 xfree (inferior_pid_ns
);
1231 /* This function is called via the inferior_created observer.
1232 This handles the case of debugging statically linked executables. */
1235 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1237 check_pid_namespace_match ();
1238 check_for_thread_db ();
1241 /* Update the thread's state (what's displayed in "info threads"),
1242 from libthread_db thread state information. */
1245 update_thread_state (struct private_thread_info
*priv
,
1246 const td_thrinfo_t
*ti_p
)
1248 priv
->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1249 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1252 /* Attach to a new thread. This function is called when we receive a
1253 TD_CREATE event or when we iterate over all threads and find one
1254 that wasn't already in our list. Returns true on success. */
1257 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1258 const td_thrinfo_t
*ti_p
)
1260 struct thread_info
*tp
;
1261 struct thread_db_info
*info
;
1263 /* If we're being called after a TD_CREATE event, we may already
1264 know about this thread. There are two ways this can happen. We
1265 may have iterated over all threads between the thread creation
1266 and the TD_CREATE event, for instance when the user has issued
1267 the `info threads' command before the SIGTRAP for hitting the
1268 thread creation breakpoint was reported. Alternatively, the
1269 thread may have exited and a new one been created with the same
1270 thread ID. In the first case we don't need to do anything; in
1271 the second case we should discard information about the dead
1272 thread and attach to the new one. */
1273 tp
= find_thread_ptid (ptid
);
1276 /* If tp->priv is NULL, then GDB is already attached to this
1277 thread, but we do not know anything about it. We can learn
1278 about it here. This can only happen if we have some other
1279 way besides libthread_db to notice new threads (i.e.
1280 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1281 exit, so this can not be a stale thread recreated with the
1283 if (tp
->priv
!= NULL
)
1285 if (!tp
->priv
->dying
)
1288 delete_thread (ptid
);
1293 /* Under GNU/Linux, we have to attach to each and every thread. */
1294 if (target_has_execution
1299 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1303 /* Error, stop iterating. */
1308 /* Pretend this thread doesn't exist yet, and keep
1313 /* Otherwise, we sucessfully attached to the thread. */
1316 info
= get_thread_db_info (ptid_get_pid (ptid
));
1317 record_thread (info
, tp
, ptid
, th_p
, ti_p
);
1321 /* Record a new thread in GDB's thread list. Creates the thread's
1322 private info. If TP is NULL, creates a new thread. Otherwise,
1326 record_thread (struct thread_db_info
*info
,
1327 struct thread_info
*tp
,
1328 ptid_t ptid
, const td_thrhandle_t
*th_p
,
1329 const td_thrinfo_t
*ti_p
)
1332 struct private_thread_info
*priv
;
1333 int new_thread
= (tp
== NULL
);
1335 /* A thread ID of zero may mean the thread library has not
1336 initialized yet. Leave private == NULL until the thread library
1338 if (ti_p
->ti_tid
== 0)
1341 /* Construct the thread's private data. */
1342 priv
= xmalloc (sizeof (struct private_thread_info
));
1343 memset (priv
, 0, sizeof (struct private_thread_info
));
1346 priv
->tid
= ti_p
->ti_tid
;
1347 update_thread_state (priv
, ti_p
);
1349 /* Add the thread to GDB's thread list. If we already know about a
1350 thread with this PTID, but it's marked exited, then the kernel
1351 reused the tid of an old thread. */
1352 if (tp
== NULL
|| tp
->state
== THREAD_EXITED
)
1353 tp
= add_thread_with_info (ptid
, priv
);
1357 /* Enable thread event reporting for this thread, except when
1358 debugging a core file. */
1359 if (target_has_execution
&& thread_db_use_events () && new_thread
)
1361 err
= info
->td_thr_event_enable_p (th_p
, 1);
1363 error (_("Cannot enable thread event reporting for %s: %s"),
1364 target_pid_to_str (ptid
), thread_db_err_str (err
));
1367 if (target_has_execution
)
1368 check_thread_signals ();
1372 detach_thread (ptid_t ptid
)
1374 struct thread_info
*thread_info
;
1376 /* Don't delete the thread now, because it still reports as active
1377 until it has executed a few instructions after the event
1378 breakpoint - if we deleted it now, "info threads" would cause us
1379 to re-attach to it. Just mark it as having had a TD_DEATH
1380 event. This means that we won't delete it from our thread list
1381 until we notice that it's dead (via prune_threads), or until
1382 something re-uses its thread ID. We'll report the thread exit
1383 when the underlying LWP dies. */
1384 thread_info
= find_thread_ptid (ptid
);
1385 gdb_assert (thread_info
!= NULL
&& thread_info
->priv
!= NULL
);
1386 thread_info
->priv
->dying
= 1;
1390 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1392 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1393 struct thread_db_info
*info
;
1395 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1399 if (target_has_execution
&& thread_db_use_events ())
1401 disable_thread_event_reporting (info
);
1403 /* Delete the old thread event breakpoints. Note that
1404 unlike when mourning, we can remove them here because
1405 there's still a live inferior to poke at. In any case,
1406 GDB will not try to insert anything in the inferior when
1407 removing a breakpoint. */
1408 remove_thread_event_breakpoints ();
1411 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1414 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1416 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1418 /* If there are no more processes using libpthread, detach the
1419 thread_db target ops. */
1420 if (!thread_db_list
)
1421 unpush_target (&thread_db_ops
);
1424 /* Check if PID is currently stopped at the location of a thread event
1425 breakpoint location. If it is, read the event message and act upon
1429 check_event (ptid_t ptid
)
1431 struct regcache
*regcache
= get_thread_regcache (ptid
);
1432 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1438 struct thread_db_info
*info
;
1440 info
= get_thread_db_info (ptid_get_pid (ptid
));
1442 /* Bail out early if we're not at a thread event breakpoint. */
1443 stop_pc
= regcache_read_pc (regcache
);
1444 if (!target_supports_stopped_by_sw_breakpoint ())
1445 stop_pc
-= gdbarch_decr_pc_after_break (gdbarch
);
1447 if (stop_pc
!= info
->td_create_bp_addr
1448 && stop_pc
!= info
->td_death_bp_addr
)
1451 /* Access an lwp we know is stopped. */
1452 info
->proc_handle
.ptid
= ptid
;
1454 /* If we have only looked at the first thread before libpthread was
1455 initialized, we may not know its thread ID yet. Make sure we do
1456 before we add another thread to the list. */
1457 if (!have_threads (ptid
))
1458 thread_db_find_new_threads_1 (ptid
);
1460 /* If we are at a create breakpoint, we do not know what new lwp
1461 was created and cannot specifically locate the event message for it.
1462 We have to call td_ta_event_getmsg() to get
1463 the latest message. Since we have no way of correlating whether
1464 the event message we get back corresponds to our breakpoint, we must
1465 loop and read all event messages, processing them appropriately.
1466 This guarantees we will process the correct message before continuing
1467 from the breakpoint.
1469 Currently, death events are not enabled. If they are enabled,
1470 the death event can use the td_thr_event_getmsg() interface to
1471 get the message specifically for that lwp and avoid looping
1478 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1481 if (err
== TD_NOMSG
)
1484 error (_("Cannot get thread event message: %s"),
1485 thread_db_err_str (err
));
1488 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1490 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1492 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1497 /* Call attach_thread whether or not we already know about a
1498 thread with this thread ID. */
1499 attach_thread (ptid
, msg
.th_p
, &ti
);
1505 if (!in_thread_list (ptid
))
1506 error (_("Spurious thread death event."));
1508 detach_thread (ptid
);
1513 error (_("Spurious thread event."));
1520 thread_db_wait (struct target_ops
*ops
,
1521 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1524 struct thread_db_info
*info
;
1525 struct target_ops
*beneath
= find_target_beneath (ops
);
1527 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1529 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1532 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1533 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1536 info
= get_thread_db_info (ptid_get_pid (ptid
));
1538 /* If this process isn't using thread_db, we're done. */
1542 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1544 /* New image, it may or may not end up using thread_db. Assume
1545 not unless we find otherwise. */
1546 delete_thread_db_info (ptid_get_pid (ptid
));
1547 if (!thread_db_list
)
1548 unpush_target (&thread_db_ops
);
1550 /* Thread event breakpoints are deleted by
1551 update_breakpoints_after_exec. */
1556 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1557 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1558 /* Check for a thread event. */
1561 /* Fill in the thread's user-level thread id and status. */
1562 thread_from_lwp (ptid
);
1568 thread_db_mourn_inferior (struct target_ops
*ops
)
1570 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1572 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1574 target_beneath
->to_mourn_inferior (target_beneath
);
1576 /* Delete the old thread event breakpoints. Do this after mourning
1577 the inferior, so that we don't try to uninsert them. */
1578 remove_thread_event_breakpoints ();
1580 /* Detach thread_db target ops. */
1581 if (!thread_db_list
)
1582 unpush_target (ops
);
1585 struct callback_data
1587 struct thread_db_info
*info
;
1592 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1597 struct thread_info
*tp
;
1598 struct callback_data
*cb_data
= data
;
1599 struct thread_db_info
*info
= cb_data
->info
;
1601 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1603 error (_("find_new_threads_callback: cannot get thread info: %s"),
1604 thread_db_err_str (err
));
1606 if (ti
.ti_lid
== -1)
1608 /* A thread with kernel thread ID -1 is either a thread that
1609 exited and was joined, or a thread that is being created but
1610 hasn't started yet, and that is reusing the tcb/stack of a
1611 thread that previously exited and was joined. (glibc marks
1612 terminated and joined threads with kernel thread ID -1. See
1614 if (libthread_db_debug
)
1615 fprintf_unfiltered (gdb_stdlog
,
1616 "thread_db: skipping exited and "
1617 "joined thread (0x%lx)\n", ti
.ti_tid
);
1623 /* A thread ID of zero means that this is the main thread, but
1624 glibc has not yet initialized thread-local storage and the
1625 pthread library. We do not know what the thread's TID will
1626 be yet. Just enable event reporting and otherwise ignore
1629 /* In that case, we're not stopped in a fork syscall and don't
1630 need this glibc bug workaround. */
1631 info
->need_stale_parent_threads_check
= 0;
1633 if (target_has_execution
&& thread_db_use_events ())
1635 err
= info
->td_thr_event_enable_p (th_p
, 1);
1637 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1638 (int) ti
.ti_lid
, thread_db_err_str (err
));
1644 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1645 bit expensive, as it needs to open /proc/pid/status, so try to
1646 avoid doing the work if we know we don't have to. */
1647 if (info
->need_stale_parent_threads_check
)
1649 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1651 if (tgid
!= -1 && tgid
!= info
->pid
)
1655 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1656 tp
= find_thread_ptid (ptid
);
1657 if (tp
== NULL
|| tp
->priv
== NULL
)
1659 if (attach_thread (ptid
, th_p
, &ti
))
1660 cb_data
->new_threads
+= 1;
1662 /* Problem attaching this thread; perhaps it exited before we
1664 This could mean that the thread list inside glibc itself is in
1665 inconsistent state, and libthread_db could go on looping forever
1666 (observed with glibc-2.3.6). To prevent that, terminate
1667 iteration: thread_db_find_new_threads_2 will retry. */
1670 else if (target_has_execution
&& !thread_db_use_events ())
1672 /* Need to update this if not using the libthread_db events
1673 (particularly, the TD_DEATH event). */
1674 update_thread_state (tp
->priv
, &ti
);
1680 /* Helper for thread_db_find_new_threads_2.
1681 Returns number of new threads found. */
1684 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1687 struct callback_data data
;
1688 td_err_e err
= TD_ERR
;
1691 data
.new_threads
= 0;
1693 /* See comment in thread_db_update_thread_list. */
1694 gdb_assert (!target_has_execution
|| thread_db_use_events ());
1698 /* Iterate over all user-space threads to discover new threads. */
1699 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1700 find_new_threads_callback
,
1703 TD_THR_LOWEST_PRIORITY
,
1705 TD_THR_ANY_USER_FLAGS
);
1707 CATCH (except
, RETURN_MASK_ERROR
)
1709 if (libthread_db_debug
)
1711 exception_fprintf (gdb_stdlog
, except
,
1712 "Warning: find_new_threads_once: ");
1717 if (libthread_db_debug
)
1719 fprintf_unfiltered (gdb_stdlog
,
1720 _("Found %d new threads in iteration %d.\n"),
1721 data
.new_threads
, iteration
);
1727 return data
.new_threads
;
1730 /* Search for new threads, accessing memory through stopped thread
1731 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1732 searches in a row do not discover any new threads. */
1735 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1737 td_err_e err
= TD_OK
;
1738 struct thread_db_info
*info
;
1741 info
= get_thread_db_info (ptid_get_pid (ptid
));
1743 /* Access an lwp we know is stopped. */
1744 info
->proc_handle
.ptid
= ptid
;
1748 /* Require 4 successive iterations which do not find any new threads.
1749 The 4 is a heuristic: there is an inherent race here, and I have
1750 seen that 2 iterations in a row are not always sufficient to
1751 "capture" all threads. */
1752 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1753 if (find_new_threads_once (info
, i
, &err
) != 0)
1755 /* Found some new threads. Restart the loop from beginning. */
1760 find_new_threads_once (info
, 0, &err
);
1763 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1767 thread_db_find_new_threads_1 (ptid_t ptid
)
1769 thread_db_find_new_threads_2 (ptid
, 0);
1773 update_thread_core (struct lwp_info
*info
, void *closure
)
1775 info
->core
= linux_common_core_of_thread (info
->ptid
);
1779 /* Update the thread list using td_ta_thr_iter. */
1782 thread_db_update_thread_list_td_ta_thr_iter (struct target_ops
*ops
)
1784 struct thread_db_info
*info
;
1785 struct inferior
*inf
;
1791 struct thread_info
*thread
;
1796 info
= get_thread_db_info (inf
->pid
);
1800 thread
= any_live_thread_of_process (inf
->pid
);
1801 if (thread
== NULL
|| thread
->executing
)
1804 thread_db_find_new_threads_1 (thread
->ptid
);
1808 /* Implement the to_update_thread_list target method for this
1812 thread_db_update_thread_list (struct target_ops
*ops
)
1814 /* It's best to avoid td_ta_thr_iter if possible. That walks data
1815 structures in the inferior's address space that may be corrupted,
1816 or, if the target is running, the list may change while we walk
1817 it. In the latter case, it's possible that a thread exits just
1818 at the exact time that causes GDB to get stuck in an infinite
1819 loop. To avoid pausing all threads whenever the core wants to
1820 refresh the thread list, if the kernel supports clone events
1821 (meaning we're always already attached to all LWPs), we use
1822 thread_from_lwp immediately when we see an LWP stop. That uses
1823 thread_db entry points that do not walk libpthread's thread list,
1824 so should be safe, as well as more efficient. */
1825 if (target_has_execution
&& !thread_db_use_events ())
1826 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1828 thread_db_update_thread_list_td_ta_thr_iter (ops
);
1830 if (target_has_execution
)
1831 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1832 update_thread_core
, NULL
);
1836 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1838 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1839 struct target_ops
*beneath
;
1841 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1843 static char buf
[64];
1846 tid
= thread_info
->priv
->tid
;
1847 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1848 tid
, ptid_get_lwp (ptid
));
1853 beneath
= find_target_beneath (ops
);
1854 return beneath
->to_pid_to_str (beneath
, ptid
);
1857 /* Return a string describing the state of the thread specified by
1861 thread_db_extra_thread_info (struct target_ops
*self
,
1862 struct thread_info
*info
)
1864 if (info
->priv
== NULL
)
1867 if (info
->priv
->dying
)
1873 /* Get the address of the thread local variable in load module LM which
1874 is stored at OFFSET within the thread local storage for thread PTID. */
1877 thread_db_get_thread_local_address (struct target_ops
*ops
,
1882 struct thread_info
*thread_info
;
1883 struct target_ops
*beneath
;
1885 /* If we have not discovered any threads yet, check now. */
1886 if (!have_threads (ptid
))
1887 thread_db_find_new_threads_1 (ptid
);
1889 /* Find the matching thread. */
1890 thread_info
= find_thread_ptid (ptid
);
1892 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1896 struct thread_db_info
*info
;
1898 info
= get_thread_db_info (ptid_get_pid (ptid
));
1900 /* Finally, get the address of the variable. */
1903 /* glibc doesn't provide the needed interface. */
1904 if (!info
->td_thr_tls_get_addr_p
)
1905 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1906 _("No TLS library support"));
1908 /* Note the cast through uintptr_t: this interface only works if
1909 a target address fits in a psaddr_t, which is a host pointer.
1910 So a 32-bit debugger can not access 64-bit TLS through this. */
1911 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1912 (psaddr_t
)(uintptr_t) lm
,
1917 /* If glibc doesn't provide the needed interface throw an error
1918 that LM is zero - normally cases it should not be. */
1919 if (!info
->td_thr_tlsbase_p
)
1920 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1921 _("TLS load module not found"));
1923 /* This code path handles the case of -static -pthread executables:
1924 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1925 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1926 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1927 The constant number 1 depends on GNU __libc_setup_tls
1928 initialization of l_tls_modid to 1. */
1929 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1931 address
= (char *) address
+ offset
;
1934 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1935 /* The memory hasn't been allocated, yet. */
1936 if (err
== TD_NOTALLOC
)
1937 /* Now, if libthread_db provided the initialization image's
1938 address, we *could* try to build a non-lvalue value from
1939 the initialization image. */
1940 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1941 _("TLS not allocated yet"));
1944 /* Something else went wrong. */
1946 throw_error (TLS_GENERIC_ERROR
,
1947 (("%s")), thread_db_err_str (err
));
1949 /* Cast assuming host == target. Joy. */
1950 /* Do proper sign extension for the target. */
1951 gdb_assert (exec_bfd
);
1952 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1953 ? (CORE_ADDR
) (intptr_t) address
1954 : (CORE_ADDR
) (uintptr_t) address
);
1957 beneath
= find_target_beneath (ops
);
1958 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1961 /* Implement the to_get_ada_task_ptid target method for this target. */
1964 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1966 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1967 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1971 thread_db_resume (struct target_ops
*ops
,
1972 ptid_t ptid
, int step
, enum gdb_signal signo
)
1974 struct target_ops
*beneath
= find_target_beneath (ops
);
1975 struct thread_db_info
*info
;
1977 if (ptid_equal (ptid
, minus_one_ptid
))
1978 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1980 info
= get_thread_db_info (ptid_get_pid (ptid
));
1982 /* This workaround is only needed for child fork lwps stopped in a
1983 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1984 workaround can be disabled. */
1986 info
->need_stale_parent_threads_check
= 0;
1988 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1991 /* qsort helper function for info_auto_load_libthread_db, sort the
1992 thread_db_info pointers primarily by their FILENAME and secondarily by their
1993 PID, both in ascending order. */
1996 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1998 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1999 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
2002 retval
= strcmp (a
->filename
, b
->filename
);
2006 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
2009 /* Implement 'info auto-load libthread-db'. */
2012 info_auto_load_libthread_db (char *args
, int from_tty
)
2014 struct ui_out
*uiout
= current_uiout
;
2015 const char *cs
= args
? args
: "";
2016 struct thread_db_info
*info
, **array
;
2017 unsigned info_count
, unique_filenames
;
2018 size_t max_filename_len
, max_pids_len
, pids_len
;
2019 struct cleanup
*back_to
;
2023 cs
= skip_spaces_const (cs
);
2025 error (_("'info auto-load libthread-db' does not accept any parameters"));
2028 for (info
= thread_db_list
; info
; info
= info
->next
)
2029 if (info
->filename
!= NULL
)
2032 array
= xmalloc (sizeof (*array
) * info_count
);
2033 back_to
= make_cleanup (xfree
, array
);
2036 for (info
= thread_db_list
; info
; info
= info
->next
)
2037 if (info
->filename
!= NULL
)
2038 array
[info_count
++] = info
;
2040 /* Sort ARRAY by filenames and PIDs. */
2042 qsort (array
, info_count
, sizeof (*array
),
2043 info_auto_load_libthread_db_compare
);
2045 /* Calculate the number of unique filenames (rows) and the maximum string
2046 length of PIDs list for the unique filenames (columns). */
2048 unique_filenames
= 0;
2049 max_filename_len
= 0;
2052 for (i
= 0; i
< info_count
; i
++)
2054 int pid
= array
[i
]->pid
;
2055 size_t this_pid_len
;
2057 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2060 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2063 max_filename_len
= max (max_filename_len
,
2064 strlen (array
[i
]->filename
));
2068 pids_len
-= strlen (", ");
2069 max_pids_len
= max (max_pids_len
, pids_len
);
2073 pids_len
+= this_pid_len
+ strlen (", ");
2077 pids_len
-= strlen (", ");
2078 max_pids_len
= max (max_pids_len
, pids_len
);
2081 /* Table header shifted right by preceding "libthread-db: " would not match
2083 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2084 ui_out_text (uiout
, "\n");
2086 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2087 "LinuxThreadDbTable");
2089 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2091 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2092 ui_out_table_body (uiout
);
2094 pids
= xmalloc (max_pids_len
+ 1);
2095 make_cleanup (xfree
, pids
);
2097 /* Note I is incremented inside the cycle, not at its end. */
2098 for (i
= 0; i
< info_count
;)
2100 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2104 ui_out_field_string (uiout
, "filename", info
->filename
);
2107 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2109 if (pids_end
!= pids
)
2114 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2115 "%u", array
[i
]->pid
);
2116 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2122 ui_out_field_string (uiout
, "pids", pids
);
2124 ui_out_text (uiout
, "\n");
2125 do_cleanups (chain
);
2128 do_cleanups (back_to
);
2130 if (info_count
== 0)
2131 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2135 init_thread_db_ops (void)
2137 thread_db_ops
.to_shortname
= "multi-thread";
2138 thread_db_ops
.to_longname
= "multi-threaded child process.";
2139 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2140 thread_db_ops
.to_detach
= thread_db_detach
;
2141 thread_db_ops
.to_wait
= thread_db_wait
;
2142 thread_db_ops
.to_resume
= thread_db_resume
;
2143 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2144 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2145 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2146 thread_db_ops
.to_stratum
= thread_stratum
;
2147 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2148 thread_db_ops
.to_get_thread_local_address
2149 = thread_db_get_thread_local_address
;
2150 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2151 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2152 thread_db_ops
.to_magic
= OPS_MAGIC
;
2154 complete_target_initialization (&thread_db_ops
);
2157 /* Provide a prototype to silence -Wmissing-prototypes. */
2158 extern initialize_file_ftype _initialize_thread_db
;
2161 _initialize_thread_db (void)
2163 init_thread_db_ops ();
2165 /* Defer loading of libthread_db.so until inferior is running.
2166 This allows gdb to load correct libthread_db for a given
2167 executable -- there could be mutiple versions of glibc,
2168 compiled with LinuxThreads or NPTL, and until there is
2169 a running inferior, we can't tell which libthread_db is
2170 the correct one to load. */
2172 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2174 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2176 &libthread_db_search_path
, _("\
2177 Set search path for libthread_db."), _("\
2178 Show the current search path or libthread_db."), _("\
2179 This path is used to search for libthread_db to be loaded into \
2181 Its value is a colon (':') separate list of directories to search.\n\
2182 Setting the search path to an empty list resets it to its default value."),
2183 set_libthread_db_search_path
,
2185 &setlist
, &showlist
);
2187 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2188 &libthread_db_debug
, _("\
2189 Set libthread-db debugging."), _("\
2190 Show libthread-db debugging."), _("\
2191 When non-zero, libthread-db debugging is enabled."),
2193 show_libthread_db_debug
,
2194 &setdebuglist
, &showdebuglist
);
2196 add_setshow_boolean_cmd ("libthread-db", class_support
,
2197 &auto_load_thread_db
, _("\
2198 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2199 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2200 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2201 locations to load libthread_db compatible with the inferior.\n\
2202 Standard system libthread_db still gets loaded even with this option off.\n\
2203 This options has security implications for untrusted inferiors."),
2204 NULL
, show_auto_load_thread_db
,
2205 auto_load_set_cmdlist_get (),
2206 auto_load_show_cmdlist_get ());
2208 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2209 _("Print the list of loaded inferior specific libthread_db.\n\
2210 Usage: info auto-load libthread-db"),
2211 auto_load_info_cmdlist_get ());
2213 /* Add ourselves to objfile event chain. */
2214 observer_attach_new_objfile (thread_db_new_objfile
);
2216 /* Add ourselves to inferior_created event chain.
2217 This is needed to handle debugging statically linked programs where
2218 the new_objfile observer won't get called for libpthread. */
2219 observer_attach_inferior_created (thread_db_inferior_created
);