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"
47 #include "nat/linux-namespaces.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_init_ftype
*td_init_p
;
178 td_ta_new_ftype
*td_ta_new_p
;
179 td_ta_map_lwp2thr_ftype
*td_ta_map_lwp2thr_p
;
180 td_ta_thr_iter_ftype
*td_ta_thr_iter_p
;
181 td_ta_event_addr_ftype
*td_ta_event_addr_p
;
182 td_ta_set_event_ftype
*td_ta_set_event_p
;
183 td_ta_clear_event_ftype
*td_ta_clear_event_p
;
184 td_ta_event_getmsg_ftype
* td_ta_event_getmsg_p
;
185 td_thr_validate_ftype
*td_thr_validate_p
;
186 td_thr_get_info_ftype
*td_thr_get_info_p
;
187 td_thr_event_enable_ftype
*td_thr_event_enable_p
;
188 td_thr_tls_get_addr_ftype
*td_thr_tls_get_addr_p
;
189 td_thr_tlsbase_ftype
*td_thr_tlsbase_p
;
192 /* List of known processes using thread_db, and the required
194 struct thread_db_info
*thread_db_list
;
196 static void thread_db_find_new_threads_1 (ptid_t ptid
);
197 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
199 static void check_thread_signals (void);
201 static void record_thread (struct thread_db_info
*info
,
202 struct thread_info
*tp
,
203 ptid_t ptid
, const td_thrhandle_t
*th_p
,
204 const td_thrinfo_t
*ti_p
);
206 /* Add the current inferior to the list of processes using libpthread.
207 Return a pointer to the newly allocated object that was added to
208 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
211 static struct thread_db_info
*
212 add_thread_db_info (void *handle
)
214 struct thread_db_info
*info
;
216 info
= xcalloc (1, sizeof (*info
));
217 info
->pid
= ptid_get_pid (inferior_ptid
);
218 info
->handle
= handle
;
220 /* The workaround works by reading from /proc/pid/status, so it is
221 disabled for core files. */
222 if (target_has_execution
)
223 info
->need_stale_parent_threads_check
= 1;
225 info
->next
= thread_db_list
;
226 thread_db_list
= info
;
231 /* Return the thread_db_info object representing the bookkeeping
232 related to process PID, if any; NULL otherwise. */
234 static struct thread_db_info
*
235 get_thread_db_info (int pid
)
237 struct thread_db_info
*info
;
239 for (info
= thread_db_list
; info
; info
= info
->next
)
240 if (pid
== info
->pid
)
246 /* When PID has exited or has been detached, we no longer want to keep
247 track of it as using libpthread. Call this function to discard
248 thread_db related info related to PID. Note that this closes
249 LIBTHREAD_DB_SO's dlopen'ed handle. */
252 delete_thread_db_info (int pid
)
254 struct thread_db_info
*info
, *info_prev
;
258 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
259 if (pid
== info
->pid
)
265 if (info
->handle
!= NULL
)
266 dlclose (info
->handle
);
268 xfree (info
->filename
);
271 info_prev
->next
= info
->next
;
273 thread_db_list
= info
->next
;
278 /* Prototypes for local functions. */
279 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
280 const td_thrinfo_t
*ti_p
);
281 static void detach_thread (ptid_t ptid
);
284 /* Use "struct private_thread_info" to cache thread state. This is
285 a substantial optimization. */
287 struct private_thread_info
289 /* Flag set when we see a TD_DEATH event for this thread. */
290 unsigned int dying
:1;
292 /* Cached thread state. */
299 thread_db_err_str (td_err_e err
)
306 return "generic 'call succeeded'";
308 return "generic error";
310 return "no thread to satisfy query";
312 return "no sync handle to satisfy query";
314 return "no LWP to satisfy query";
316 return "invalid process handle";
318 return "invalid thread handle";
320 return "invalid synchronization handle";
322 return "invalid thread agent";
324 return "invalid key";
326 return "no event message for getmsg";
328 return "FPU register set not available";
330 return "application not linked with libthread";
332 return "requested event is not supported";
334 return "capability not available";
336 return "debugger service failed";
338 return "operation not applicable to";
340 return "no thread-specific data for this thread";
342 return "malloc failed";
344 return "only part of register set was written/read";
346 return "X register set not available for this thread";
347 #ifdef THREAD_DB_HAS_TD_NOTALLOC
349 return "thread has not yet allocated TLS for given module";
351 #ifdef THREAD_DB_HAS_TD_VERSION
353 return "versions of libpthread and libthread_db do not match";
355 #ifdef THREAD_DB_HAS_TD_NOTLS
357 return "there is no TLS segment in the given module";
360 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
365 /* Return 1 if any threads have been registered. There may be none if
366 the threading library is not fully initialized yet. */
369 have_threads_callback (struct thread_info
*thread
, void *args
)
371 int pid
= * (int *) args
;
373 if (ptid_get_pid (thread
->ptid
) != pid
)
376 return thread
->priv
!= NULL
;
380 have_threads (ptid_t ptid
)
382 int pid
= ptid_get_pid (ptid
);
384 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
388 /* Fetch the user-level thread id of PTID. */
391 thread_from_lwp (ptid_t ptid
)
396 struct thread_db_info
*info
;
397 struct thread_info
*tp
;
399 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
402 /* This ptid comes from linux-nat.c, which should always fill in the
404 gdb_assert (ptid_get_lwp (ptid
) != 0);
406 info
= get_thread_db_info (ptid_get_pid (ptid
));
408 /* Access an lwp we know is stopped. */
409 info
->proc_handle
.ptid
= ptid
;
410 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
413 error (_("Cannot find user-level thread for LWP %ld: %s"),
414 ptid_get_lwp (ptid
), thread_db_err_str (err
));
416 err
= info
->td_thr_get_info_p (&th
, &ti
);
418 error (_("thread_get_info_callback: cannot get thread info: %s"),
419 thread_db_err_str (err
));
421 /* Fill the cache. */
422 tp
= find_thread_ptid (ptid
);
423 record_thread (info
, tp
, ptid
, &th
, &ti
);
427 /* See linux-nat.h. */
430 thread_db_notice_clone (ptid_t parent
, ptid_t child
)
435 struct thread_db_info
*info
;
437 info
= get_thread_db_info (ptid_get_pid (child
));
442 thread_from_lwp (child
);
444 /* If we do not know about the main thread yet, this would be a good
446 thread_from_lwp (parent
);
451 verbose_dlsym (void *handle
, const char *name
)
453 void *sym
= dlsym (handle
, name
);
455 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
461 enable_thread_event (td_event_e event
, CORE_ADDR
*bp
)
465 struct thread_db_info
*info
;
467 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
469 /* Access an lwp we know is stopped. */
470 info
->proc_handle
.ptid
= inferior_ptid
;
472 /* Get the breakpoint address for thread EVENT. */
473 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
477 /* Set up the breakpoint. */
478 gdb_assert (exec_bfd
);
479 (*bp
) = (gdbarch_convert_from_func_ptr_addr
481 /* Do proper sign extension for the target. */
482 (bfd_get_sign_extend_vma (exec_bfd
) > 0
483 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
484 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
486 create_thread_event_breakpoint (target_gdbarch (), *bp
);
491 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
492 return 1 if this version is lower (and not equal) to
493 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
496 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
498 struct bound_minimal_symbol version_msym
;
499 CORE_ADDR version_addr
;
501 int err
, got
, retval
= 0;
503 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
504 if (version_msym
.minsym
== NULL
)
507 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
508 got
= target_read_string (version_addr
, &version
, 32, &err
);
509 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
513 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
514 && (major
< ver_major_min
515 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
523 enable_thread_event_reporting (void)
525 td_thr_events_t events
;
527 struct thread_db_info
*info
;
529 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
531 /* We cannot use the thread event reporting facility if these
532 functions aren't available. */
533 if (info
->td_ta_event_addr_p
== NULL
534 || info
->td_ta_set_event_p
== NULL
535 || info
->td_ta_event_getmsg_p
== NULL
536 || info
->td_thr_event_enable_p
== NULL
)
539 /* Set the process wide mask saying which events we're interested in. */
540 td_event_emptyset (&events
);
541 td_event_addset (&events
, TD_CREATE
);
543 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
544 commit 2e4581e4fba917f1779cd0a010a45698586c190a
545 * manager.c (pthread_exited): Correctly report event as TD_REAP
546 instead of TD_DEATH. Fix comments.
547 where event reporting facility is broken for TD_DEATH events,
548 so don't enable it if we have glibc but a lower version. */
549 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
550 td_event_addset (&events
, TD_DEATH
);
552 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
555 warning (_("Unable to set global thread event mask: %s"),
556 thread_db_err_str (err
));
560 /* Delete previous thread event breakpoints, if any. */
561 remove_thread_event_breakpoints ();
562 info
->td_create_bp_addr
= 0;
563 info
->td_death_bp_addr
= 0;
565 /* Set up the thread creation event. */
566 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
569 warning (_("Unable to get location for thread creation breakpoint: %s"),
570 thread_db_err_str (err
));
574 /* Set up the thread death event. */
575 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
578 warning (_("Unable to get location for thread death breakpoint: %s"),
579 thread_db_err_str (err
));
584 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
587 Return 1 if the caller should abort libthread_db initialization. Return 0
591 thread_db_find_new_threads_silently (ptid_t ptid
)
596 thread_db_find_new_threads_2 (ptid
, 1);
599 CATCH (except
, RETURN_MASK_ERROR
)
601 if (libthread_db_debug
)
602 exception_fprintf (gdb_stdlog
, except
,
603 "Warning: thread_db_find_new_threads_silently: ");
605 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
606 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
607 where calls to td_thr_get_info fail with TD_ERR for statically linked
608 executables if td_thr_get_info is called before glibc has initialized
611 If the nptl bug is NOT present in the inferior and still thread_db
612 reports an error return 1. It means the inferior has corrupted thread
613 list and GDB should fall back only to LWPs.
615 If the nptl bug is present in the inferior return 0 to silently ignore
616 such errors, and let gdb enumerate threads again later. In such case
617 GDB cannot properly display LWPs if the inferior thread list is
618 corrupted. For core files it does not apply, no 'later enumeration'
621 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
623 exception_fprintf (gdb_stderr
, except
,
624 _("Warning: couldn't activate thread debugging "
625 "using libthread_db: "));
634 /* Lookup a library in which given symbol resides.
635 Note: this is looking in GDB process, not in the inferior.
636 Returns library name, or NULL. */
639 dladdr_to_soname (const void *addr
)
643 if (dladdr (addr
, &info
) != 0)
644 return info
.dli_fname
;
648 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
650 Failure could happen if libthread_db does not have symbols we expect,
651 or when it refuses to work with the current inferior (e.g. due to
652 version mismatch between libthread_db and libpthread). */
655 try_thread_db_load_1 (struct thread_db_info
*info
)
659 /* Initialize pointers to the dynamic library functions we will use.
660 Essential functions first. */
662 #define TDB_VERBOSE_DLSYM(info, func) \
663 info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
665 #define TDB_DLSYM(info, func) \
666 info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
675 CHK (TDB_VERBOSE_DLSYM (info
, td_init
));
677 err
= info
->td_init_p ();
680 warning (_("Cannot initialize libthread_db: %s"),
681 thread_db_err_str (err
));
685 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_new
));
687 /* Initialize the structure that identifies the child process. */
688 info
->proc_handle
.ptid
= inferior_ptid
;
690 /* Now attempt to open a connection to the thread library. */
691 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
694 if (libthread_db_debug
)
695 fprintf_unfiltered (gdb_stdlog
, _("td_ta_new failed: %s\n"),
696 thread_db_err_str (err
));
701 #ifdef THREAD_DB_HAS_TD_VERSION
704 /* The errors above are not unexpected and silently ignored:
705 they just mean we haven't found correct version of
709 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
714 /* These are essential. */
715 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_map_lwp2thr
));
716 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_thr_iter
));
717 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_validate
));
718 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_get_info
));
720 /* These are not essential. */
721 TDB_DLSYM (info
, td_ta_event_addr
);
722 TDB_DLSYM (info
, td_ta_set_event
);
723 TDB_DLSYM (info
, td_ta_clear_event
);
724 TDB_DLSYM (info
, td_ta_event_getmsg
);
725 TDB_DLSYM (info
, td_thr_event_enable
);
726 TDB_DLSYM (info
, td_thr_tls_get_addr
);
727 TDB_DLSYM (info
, td_thr_tlsbase
);
729 #undef TDB_VERBOSE_DLSYM
733 /* It's best to avoid td_ta_thr_iter if possible. That walks data
734 structures in the inferior's address space that may be corrupted,
735 or, if the target is running, may change while we walk them. If
736 there's execution (and /proc is mounted), then we're already
737 attached to all LWPs. Use thread_from_lwp, which uses
738 td_ta_map_lwp2thr instead, which does not walk the thread list.
740 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
741 currently on core targets, as it uses ptrace directly. */
742 if (target_has_execution
743 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid
)))
746 int pid
= ptid_get_pid (inferior_ptid
);
748 linux_stop_and_wait_all_lwps ();
751 if (ptid_get_pid (lp
->ptid
) == pid
)
752 thread_from_lwp (lp
->ptid
);
754 linux_unstop_all_lwps ();
756 else if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
758 /* Even if libthread_db initializes, if the thread list is
759 corrupted, we'd not manage to list any threads. Better reject this
760 thread_db, and fall back to at least listing LWPs. */
764 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
766 if (*libthread_db_search_path
|| libthread_db_debug
)
768 struct ui_file
*file
;
771 library
= dladdr_to_soname (*info
->td_ta_new_p
);
773 library
= LIBTHREAD_DB_SO
;
775 /* If we'd print this to gdb_stdout when debug output is
776 disabled, still print it to gdb_stdout if debug output is
777 enabled. User visible output should not depend on debug
779 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
780 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
784 /* The thread library was detected. Activate the thread_db target
785 if this is the first process using it. */
786 if (thread_db_list
->next
== NULL
)
787 push_target (&thread_db_ops
);
789 /* Enable event reporting, but not when debugging a core file. */
790 if (target_has_execution
&& thread_db_use_events ())
791 enable_thread_event_reporting ();
796 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
797 relative, or just LIBTHREAD_DB. */
800 try_thread_db_load (const char *library
, int check_auto_load_safe
)
803 struct thread_db_info
*info
;
805 if (libthread_db_debug
)
806 fprintf_unfiltered (gdb_stdlog
,
807 _("Trying host libthread_db library: %s.\n"),
810 if (check_auto_load_safe
)
812 if (access (library
, R_OK
) != 0)
814 /* Do not print warnings by file_is_auto_load_safe if the library does
815 not exist at this place. */
816 if (libthread_db_debug
)
817 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
818 safe_strerror (errno
));
822 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
823 "library \"%s\" from explicit "
829 handle
= dlopen (library
, RTLD_NOW
);
832 if (libthread_db_debug
)
833 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
837 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
841 td_init
= dlsym (handle
, "td_init");
844 const char *const libpath
= dladdr_to_soname (td_init
);
847 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
852 info
= add_thread_db_info (handle
);
854 /* Do not save system library name, that one is always trusted. */
855 if (strchr (library
, '/') != NULL
)
856 info
->filename
= gdb_realpath (library
);
858 if (try_thread_db_load_1 (info
))
861 /* This library "refused" to work on current inferior. */
862 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
866 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
867 Try loading libthread_db in directory(OBJ)/SUBDIR.
868 SUBDIR may be NULL. It may also be something like "../lib64".
869 The result is true for success. */
872 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
874 struct cleanup
*cleanup
;
877 const char *obj_name
= objfile_name (obj
);
879 if (obj_name
[0] != '/')
881 warning (_("Expected absolute pathname for libpthread in the"
882 " inferior, but got %s."), obj_name
);
886 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
887 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
888 cleanup
= make_cleanup (xfree
, path
);
890 strcpy (path
, obj_name
);
891 cp
= strrchr (path
, '/');
892 /* This should at minimum hit the first character. */
893 gdb_assert (cp
!= NULL
);
900 strcat (cp
, LIBTHREAD_DB_SO
);
902 result
= try_thread_db_load (path
, 1);
904 do_cleanups (cleanup
);
908 /* Handle $pdir in libthread-db-search-path.
909 Look for libthread_db in directory(libpthread)/SUBDIR.
910 SUBDIR may be NULL. It may also be something like "../lib64".
911 The result is true for success. */
914 try_thread_db_load_from_pdir (const char *subdir
)
918 if (!auto_load_thread_db
)
922 if (libpthread_name_p (objfile_name (obj
)))
924 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
927 /* We may have found the separate-debug-info version of
928 libpthread, and it may live in a directory without a matching
930 if (obj
->separate_debug_objfile_backlink
!= NULL
)
931 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
940 /* Handle $sdir in libthread-db-search-path.
941 Look for libthread_db in the system dirs, or wherever a plain
942 dlopen(file_without_path) will look.
943 The result is true for success. */
946 try_thread_db_load_from_sdir (void)
948 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
951 /* Try to load libthread_db from directory DIR of length DIR_LEN.
952 The result is true for success. */
955 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
957 struct cleanup
*cleanup
;
961 if (!auto_load_thread_db
)
964 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
965 cleanup
= make_cleanup (xfree
, path
);
967 memcpy (path
, dir
, dir_len
);
969 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
971 result
= try_thread_db_load (path
, 1);
973 do_cleanups (cleanup
);
977 /* Search libthread_db_search_path for libthread_db which "agrees"
978 to work on current inferior.
979 The result is true for success. */
982 thread_db_load_search (void)
984 VEC (char_ptr
) *dir_vec
;
985 struct cleanup
*cleanups
;
989 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
990 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
992 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
994 const int pdir_len
= sizeof ("$pdir") - 1;
997 this_dir_len
= strlen (this_dir
);
999 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
1000 && (this_dir
[pdir_len
] == '\0'
1001 || this_dir
[pdir_len
] == '/'))
1003 char *subdir
= NULL
;
1004 struct cleanup
*free_subdir_cleanup
1005 = make_cleanup (null_cleanup
, NULL
);
1007 if (this_dir
[pdir_len
] == '/')
1009 subdir
= xmalloc (strlen (this_dir
));
1010 make_cleanup (xfree
, subdir
);
1011 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1013 rc
= try_thread_db_load_from_pdir (subdir
);
1014 do_cleanups (free_subdir_cleanup
);
1018 else if (strcmp (this_dir
, "$sdir") == 0)
1020 if (try_thread_db_load_from_sdir ())
1028 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1036 do_cleanups (cleanups
);
1037 if (libthread_db_debug
)
1038 fprintf_unfiltered (gdb_stdlog
,
1039 _("thread_db_load_search returning %d\n"), rc
);
1043 /* Return non-zero if the inferior has a libpthread. */
1046 has_libpthread (void)
1048 struct objfile
*obj
;
1051 if (libpthread_name_p (objfile_name (obj
)))
1057 /* Attempt to load and initialize libthread_db.
1058 Return 1 on success. */
1061 thread_db_load (void)
1063 struct thread_db_info
*info
;
1065 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1070 /* Don't attempt to use thread_db on executables not running
1072 if (!target_has_registers
)
1075 /* Don't attempt to use thread_db for remote targets. */
1076 if (!(target_can_run (¤t_target
) || core_bfd
))
1079 if (thread_db_load_search ())
1082 /* We couldn't find a libthread_db.
1083 If the inferior has a libpthread warn the user. */
1084 if (has_libpthread ())
1086 warning (_("Unable to find libthread_db matching inferior's thread"
1087 " library, thread debugging will not be available."));
1091 /* Either this executable isn't using libpthread at all, or it is
1092 statically linked. Since we can't easily distinguish these two cases,
1093 no warning is issued. */
1098 disable_thread_event_reporting (struct thread_db_info
*info
)
1100 if (info
->td_ta_clear_event_p
!= NULL
)
1102 td_thr_events_t events
;
1104 /* Set the process wide mask saying we aren't interested in any
1106 td_event_fillset (&events
);
1107 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1110 info
->td_create_bp_addr
= 0;
1111 info
->td_death_bp_addr
= 0;
1115 check_thread_signals (void)
1117 if (!thread_signals
)
1122 lin_thread_get_thread_signals (&mask
);
1123 sigemptyset (&thread_stop_set
);
1124 sigemptyset (&thread_print_set
);
1126 for (i
= 1; i
< NSIG
; i
++)
1128 if (sigismember (&mask
, i
))
1130 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1131 sigaddset (&thread_stop_set
, i
);
1132 if (signal_print_update (gdb_signal_from_host (i
), 0))
1133 sigaddset (&thread_print_set
, i
);
1140 /* Check whether thread_db is usable. This function is called when
1141 an inferior is created (or otherwise acquired, e.g. attached to)
1142 and when new shared libraries are loaded into a running process. */
1145 check_for_thread_db (void)
1147 /* Do nothing if we couldn't load libthread_db.so.1. */
1148 if (!thread_db_load ())
1152 /* This function is called via the new_objfile observer. */
1155 thread_db_new_objfile (struct objfile
*objfile
)
1157 /* This observer must always be called with inferior_ptid set
1161 /* libpthread with separate debug info has its debug info file already
1162 loaded (and notified without successful thread_db initialization)
1163 the time observer_notify_new_objfile is called for the library itself.
1164 Static executables have their separate debug info loaded already
1165 before the inferior has started. */
1166 && objfile
->separate_debug_objfile_backlink
== NULL
1167 /* Only check for thread_db if we loaded libpthread,
1168 or if this is the main symbol file.
1169 We need to check OBJF_MAINLINE to handle the case of debugging
1170 a statically linked executable AND the symbol file is specified AFTER
1171 the exec file is loaded (e.g., gdb -c core ; file foo).
1172 For dynamically linked executables, libpthread can be near the end
1173 of the list of shared libraries to load, and in an app of several
1174 thousand shared libraries, this can otherwise be painful. */
1175 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1176 || libpthread_name_p (objfile_name (objfile
))))
1177 check_for_thread_db ();
1181 check_pid_namespace_match (void)
1183 /* Check is only relevant for local targets targets. */
1184 if (target_can_run (¤t_target
))
1186 /* If the child is in a different PID namespace, its idea of its
1187 PID will differ from our idea of its PID. When we scan the
1188 child's thread list, we'll mistakenly think it has no threads
1189 since the thread PID fields won't match the PID we give to
1191 if (!linux_ns_same (ptid_get_pid (inferior_ptid
), LINUX_NS_PID
))
1193 warning (_ ("Target and debugger are in different PID "
1194 "namespaces; thread lists and other data are "
1195 "likely unreliable"));
1200 /* This function is called via the inferior_created observer.
1201 This handles the case of debugging statically linked executables. */
1204 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1206 check_pid_namespace_match ();
1207 check_for_thread_db ();
1210 /* Update the thread's state (what's displayed in "info threads"),
1211 from libthread_db thread state information. */
1214 update_thread_state (struct private_thread_info
*priv
,
1215 const td_thrinfo_t
*ti_p
)
1217 priv
->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1218 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1221 /* Attach to a new thread. This function is called when we receive a
1222 TD_CREATE event or when we iterate over all threads and find one
1223 that wasn't already in our list. Returns true on success. */
1226 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1227 const td_thrinfo_t
*ti_p
)
1229 struct thread_info
*tp
;
1230 struct thread_db_info
*info
;
1232 /* If we're being called after a TD_CREATE event, we may already
1233 know about this thread. There are two ways this can happen. We
1234 may have iterated over all threads between the thread creation
1235 and the TD_CREATE event, for instance when the user has issued
1236 the `info threads' command before the SIGTRAP for hitting the
1237 thread creation breakpoint was reported. Alternatively, the
1238 thread may have exited and a new one been created with the same
1239 thread ID. In the first case we don't need to do anything; in
1240 the second case we should discard information about the dead
1241 thread and attach to the new one. */
1242 tp
= find_thread_ptid (ptid
);
1245 /* If tp->priv is NULL, then GDB is already attached to this
1246 thread, but we do not know anything about it. We can learn
1247 about it here. This can only happen if we have some other
1248 way besides libthread_db to notice new threads (i.e.
1249 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1250 exit, so this can not be a stale thread recreated with the
1252 if (tp
->priv
!= NULL
)
1254 if (!tp
->priv
->dying
)
1257 delete_thread (ptid
);
1262 /* Under GNU/Linux, we have to attach to each and every thread. */
1263 if (target_has_execution
1268 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1272 /* Error, stop iterating. */
1277 /* Pretend this thread doesn't exist yet, and keep
1282 /* Otherwise, we sucessfully attached to the thread. */
1285 info
= get_thread_db_info (ptid_get_pid (ptid
));
1286 record_thread (info
, tp
, ptid
, th_p
, ti_p
);
1290 /* Record a new thread in GDB's thread list. Creates the thread's
1291 private info. If TP is NULL, creates a new thread. Otherwise,
1295 record_thread (struct thread_db_info
*info
,
1296 struct thread_info
*tp
,
1297 ptid_t ptid
, const td_thrhandle_t
*th_p
,
1298 const td_thrinfo_t
*ti_p
)
1301 struct private_thread_info
*priv
;
1302 int new_thread
= (tp
== NULL
);
1304 /* A thread ID of zero may mean the thread library has not
1305 initialized yet. Leave private == NULL until the thread library
1307 if (ti_p
->ti_tid
== 0)
1310 /* Construct the thread's private data. */
1311 priv
= xmalloc (sizeof (struct private_thread_info
));
1312 memset (priv
, 0, sizeof (struct private_thread_info
));
1315 priv
->tid
= ti_p
->ti_tid
;
1316 update_thread_state (priv
, ti_p
);
1318 /* Add the thread to GDB's thread list. If we already know about a
1319 thread with this PTID, but it's marked exited, then the kernel
1320 reused the tid of an old thread. */
1321 if (tp
== NULL
|| tp
->state
== THREAD_EXITED
)
1322 tp
= add_thread_with_info (ptid
, priv
);
1326 /* Enable thread event reporting for this thread, except when
1327 debugging a core file. */
1328 if (target_has_execution
&& thread_db_use_events () && new_thread
)
1330 err
= info
->td_thr_event_enable_p (th_p
, 1);
1332 error (_("Cannot enable thread event reporting for %s: %s"),
1333 target_pid_to_str (ptid
), thread_db_err_str (err
));
1336 if (target_has_execution
)
1337 check_thread_signals ();
1341 detach_thread (ptid_t ptid
)
1343 struct thread_info
*thread_info
;
1345 /* Don't delete the thread now, because it still reports as active
1346 until it has executed a few instructions after the event
1347 breakpoint - if we deleted it now, "info threads" would cause us
1348 to re-attach to it. Just mark it as having had a TD_DEATH
1349 event. This means that we won't delete it from our thread list
1350 until we notice that it's dead (via prune_threads), or until
1351 something re-uses its thread ID. We'll report the thread exit
1352 when the underlying LWP dies. */
1353 thread_info
= find_thread_ptid (ptid
);
1354 gdb_assert (thread_info
!= NULL
&& thread_info
->priv
!= NULL
);
1355 thread_info
->priv
->dying
= 1;
1359 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1361 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1362 struct thread_db_info
*info
;
1364 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1368 if (target_has_execution
&& thread_db_use_events ())
1370 disable_thread_event_reporting (info
);
1372 /* Delete the old thread event breakpoints. Note that
1373 unlike when mourning, we can remove them here because
1374 there's still a live inferior to poke at. In any case,
1375 GDB will not try to insert anything in the inferior when
1376 removing a breakpoint. */
1377 remove_thread_event_breakpoints ();
1380 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1383 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1385 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1387 /* If there are no more processes using libpthread, detach the
1388 thread_db target ops. */
1389 if (!thread_db_list
)
1390 unpush_target (&thread_db_ops
);
1393 /* Check if PID is currently stopped at the location of a thread event
1394 breakpoint location. If it is, read the event message and act upon
1398 check_event (ptid_t ptid
)
1400 struct regcache
*regcache
= get_thread_regcache (ptid
);
1401 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1407 struct thread_db_info
*info
;
1409 info
= get_thread_db_info (ptid_get_pid (ptid
));
1411 /* Bail out early if we're not at a thread event breakpoint. */
1412 stop_pc
= regcache_read_pc (regcache
);
1413 if (!target_supports_stopped_by_sw_breakpoint ())
1414 stop_pc
-= gdbarch_decr_pc_after_break (gdbarch
);
1416 if (stop_pc
!= info
->td_create_bp_addr
1417 && stop_pc
!= info
->td_death_bp_addr
)
1420 /* Access an lwp we know is stopped. */
1421 info
->proc_handle
.ptid
= ptid
;
1423 /* If we have only looked at the first thread before libpthread was
1424 initialized, we may not know its thread ID yet. Make sure we do
1425 before we add another thread to the list. */
1426 if (!have_threads (ptid
))
1427 thread_db_find_new_threads_1 (ptid
);
1429 /* If we are at a create breakpoint, we do not know what new lwp
1430 was created and cannot specifically locate the event message for it.
1431 We have to call td_ta_event_getmsg() to get
1432 the latest message. Since we have no way of correlating whether
1433 the event message we get back corresponds to our breakpoint, we must
1434 loop and read all event messages, processing them appropriately.
1435 This guarantees we will process the correct message before continuing
1436 from the breakpoint.
1438 Currently, death events are not enabled. If they are enabled,
1439 the death event can use the td_thr_event_getmsg() interface to
1440 get the message specifically for that lwp and avoid looping
1447 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1450 if (err
== TD_NOMSG
)
1453 error (_("Cannot get thread event message: %s"),
1454 thread_db_err_str (err
));
1457 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1459 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1461 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1466 /* Call attach_thread whether or not we already know about a
1467 thread with this thread ID. */
1468 attach_thread (ptid
, msg
.th_p
, &ti
);
1474 if (!in_thread_list (ptid
))
1475 error (_("Spurious thread death event."));
1477 detach_thread (ptid
);
1482 error (_("Spurious thread event."));
1489 thread_db_wait (struct target_ops
*ops
,
1490 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1493 struct thread_db_info
*info
;
1494 struct target_ops
*beneath
= find_target_beneath (ops
);
1496 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1498 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1501 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1502 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1505 info
= get_thread_db_info (ptid_get_pid (ptid
));
1507 /* If this process isn't using thread_db, we're done. */
1511 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1513 /* New image, it may or may not end up using thread_db. Assume
1514 not unless we find otherwise. */
1515 delete_thread_db_info (ptid_get_pid (ptid
));
1516 if (!thread_db_list
)
1517 unpush_target (&thread_db_ops
);
1519 /* Thread event breakpoints are deleted by
1520 update_breakpoints_after_exec. */
1525 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1526 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1527 /* Check for a thread event. */
1530 /* Fill in the thread's user-level thread id and status. */
1531 thread_from_lwp (ptid
);
1537 thread_db_mourn_inferior (struct target_ops
*ops
)
1539 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1541 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1543 target_beneath
->to_mourn_inferior (target_beneath
);
1545 /* Delete the old thread event breakpoints. Do this after mourning
1546 the inferior, so that we don't try to uninsert them. */
1547 remove_thread_event_breakpoints ();
1549 /* Detach thread_db target ops. */
1550 if (!thread_db_list
)
1551 unpush_target (ops
);
1554 struct callback_data
1556 struct thread_db_info
*info
;
1561 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1566 struct thread_info
*tp
;
1567 struct callback_data
*cb_data
= data
;
1568 struct thread_db_info
*info
= cb_data
->info
;
1570 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1572 error (_("find_new_threads_callback: cannot get thread info: %s"),
1573 thread_db_err_str (err
));
1575 if (ti
.ti_lid
== -1)
1577 /* A thread with kernel thread ID -1 is either a thread that
1578 exited and was joined, or a thread that is being created but
1579 hasn't started yet, and that is reusing the tcb/stack of a
1580 thread that previously exited and was joined. (glibc marks
1581 terminated and joined threads with kernel thread ID -1. See
1583 if (libthread_db_debug
)
1584 fprintf_unfiltered (gdb_stdlog
,
1585 "thread_db: skipping exited and "
1586 "joined thread (0x%lx)\n", ti
.ti_tid
);
1592 /* A thread ID of zero means that this is the main thread, but
1593 glibc has not yet initialized thread-local storage and the
1594 pthread library. We do not know what the thread's TID will
1595 be yet. Just enable event reporting and otherwise ignore
1598 /* In that case, we're not stopped in a fork syscall and don't
1599 need this glibc bug workaround. */
1600 info
->need_stale_parent_threads_check
= 0;
1602 if (target_has_execution
&& thread_db_use_events ())
1604 err
= info
->td_thr_event_enable_p (th_p
, 1);
1606 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1607 (int) ti
.ti_lid
, thread_db_err_str (err
));
1613 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1614 bit expensive, as it needs to open /proc/pid/status, so try to
1615 avoid doing the work if we know we don't have to. */
1616 if (info
->need_stale_parent_threads_check
)
1618 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1620 if (tgid
!= -1 && tgid
!= info
->pid
)
1624 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1625 tp
= find_thread_ptid (ptid
);
1626 if (tp
== NULL
|| tp
->priv
== NULL
)
1628 if (attach_thread (ptid
, th_p
, &ti
))
1629 cb_data
->new_threads
+= 1;
1631 /* Problem attaching this thread; perhaps it exited before we
1633 This could mean that the thread list inside glibc itself is in
1634 inconsistent state, and libthread_db could go on looping forever
1635 (observed with glibc-2.3.6). To prevent that, terminate
1636 iteration: thread_db_find_new_threads_2 will retry. */
1639 else if (target_has_execution
&& !thread_db_use_events ())
1641 /* Need to update this if not using the libthread_db events
1642 (particularly, the TD_DEATH event). */
1643 update_thread_state (tp
->priv
, &ti
);
1649 /* Helper for thread_db_find_new_threads_2.
1650 Returns number of new threads found. */
1653 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1656 struct callback_data data
;
1657 td_err_e err
= TD_ERR
;
1660 data
.new_threads
= 0;
1662 /* See comment in thread_db_update_thread_list. */
1663 gdb_assert (!target_has_execution
|| thread_db_use_events ());
1667 /* Iterate over all user-space threads to discover new threads. */
1668 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1669 find_new_threads_callback
,
1672 TD_THR_LOWEST_PRIORITY
,
1674 TD_THR_ANY_USER_FLAGS
);
1676 CATCH (except
, RETURN_MASK_ERROR
)
1678 if (libthread_db_debug
)
1680 exception_fprintf (gdb_stdlog
, except
,
1681 "Warning: find_new_threads_once: ");
1686 if (libthread_db_debug
)
1688 fprintf_unfiltered (gdb_stdlog
,
1689 _("Found %d new threads in iteration %d.\n"),
1690 data
.new_threads
, iteration
);
1696 return data
.new_threads
;
1699 /* Search for new threads, accessing memory through stopped thread
1700 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1701 searches in a row do not discover any new threads. */
1704 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1706 td_err_e err
= TD_OK
;
1707 struct thread_db_info
*info
;
1710 info
= get_thread_db_info (ptid_get_pid (ptid
));
1712 /* Access an lwp we know is stopped. */
1713 info
->proc_handle
.ptid
= ptid
;
1717 /* Require 4 successive iterations which do not find any new threads.
1718 The 4 is a heuristic: there is an inherent race here, and I have
1719 seen that 2 iterations in a row are not always sufficient to
1720 "capture" all threads. */
1721 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1722 if (find_new_threads_once (info
, i
, &err
) != 0)
1724 /* Found some new threads. Restart the loop from beginning. */
1729 find_new_threads_once (info
, 0, &err
);
1732 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1736 thread_db_find_new_threads_1 (ptid_t ptid
)
1738 thread_db_find_new_threads_2 (ptid
, 0);
1742 update_thread_core (struct lwp_info
*info
, void *closure
)
1744 info
->core
= linux_common_core_of_thread (info
->ptid
);
1748 /* Update the thread list using td_ta_thr_iter. */
1751 thread_db_update_thread_list_td_ta_thr_iter (struct target_ops
*ops
)
1753 struct thread_db_info
*info
;
1754 struct inferior
*inf
;
1760 struct thread_info
*thread
;
1765 info
= get_thread_db_info (inf
->pid
);
1769 thread
= any_live_thread_of_process (inf
->pid
);
1770 if (thread
== NULL
|| thread
->executing
)
1773 thread_db_find_new_threads_1 (thread
->ptid
);
1777 /* Implement the to_update_thread_list target method for this
1781 thread_db_update_thread_list (struct target_ops
*ops
)
1783 /* It's best to avoid td_ta_thr_iter if possible. That walks data
1784 structures in the inferior's address space that may be corrupted,
1785 or, if the target is running, the list may change while we walk
1786 it. In the latter case, it's possible that a thread exits just
1787 at the exact time that causes GDB to get stuck in an infinite
1788 loop. To avoid pausing all threads whenever the core wants to
1789 refresh the thread list, if the kernel supports clone events
1790 (meaning we're always already attached to all LWPs), we use
1791 thread_from_lwp immediately when we see an LWP stop. That uses
1792 thread_db entry points that do not walk libpthread's thread list,
1793 so should be safe, as well as more efficient. */
1794 if (target_has_execution
&& !thread_db_use_events ())
1795 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1797 thread_db_update_thread_list_td_ta_thr_iter (ops
);
1799 if (target_has_execution
)
1800 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1801 update_thread_core
, NULL
);
1805 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1807 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1808 struct target_ops
*beneath
;
1810 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1812 static char buf
[64];
1815 tid
= thread_info
->priv
->tid
;
1816 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1817 tid
, ptid_get_lwp (ptid
));
1822 beneath
= find_target_beneath (ops
);
1823 return beneath
->to_pid_to_str (beneath
, ptid
);
1826 /* Return a string describing the state of the thread specified by
1830 thread_db_extra_thread_info (struct target_ops
*self
,
1831 struct thread_info
*info
)
1833 if (info
->priv
== NULL
)
1836 if (info
->priv
->dying
)
1842 /* Get the address of the thread local variable in load module LM which
1843 is stored at OFFSET within the thread local storage for thread PTID. */
1846 thread_db_get_thread_local_address (struct target_ops
*ops
,
1851 struct thread_info
*thread_info
;
1852 struct target_ops
*beneath
;
1854 /* If we have not discovered any threads yet, check now. */
1855 if (!have_threads (ptid
))
1856 thread_db_find_new_threads_1 (ptid
);
1858 /* Find the matching thread. */
1859 thread_info
= find_thread_ptid (ptid
);
1861 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1865 struct thread_db_info
*info
;
1867 info
= get_thread_db_info (ptid_get_pid (ptid
));
1869 /* Finally, get the address of the variable. */
1872 /* glibc doesn't provide the needed interface. */
1873 if (!info
->td_thr_tls_get_addr_p
)
1874 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1875 _("No TLS library support"));
1877 /* Note the cast through uintptr_t: this interface only works if
1878 a target address fits in a psaddr_t, which is a host pointer.
1879 So a 32-bit debugger can not access 64-bit TLS through this. */
1880 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1881 (psaddr_t
)(uintptr_t) lm
,
1886 /* If glibc doesn't provide the needed interface throw an error
1887 that LM is zero - normally cases it should not be. */
1888 if (!info
->td_thr_tlsbase_p
)
1889 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1890 _("TLS load module not found"));
1892 /* This code path handles the case of -static -pthread executables:
1893 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1894 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1895 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1896 The constant number 1 depends on GNU __libc_setup_tls
1897 initialization of l_tls_modid to 1. */
1898 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1900 address
= (char *) address
+ offset
;
1903 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1904 /* The memory hasn't been allocated, yet. */
1905 if (err
== TD_NOTALLOC
)
1906 /* Now, if libthread_db provided the initialization image's
1907 address, we *could* try to build a non-lvalue value from
1908 the initialization image. */
1909 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1910 _("TLS not allocated yet"));
1913 /* Something else went wrong. */
1915 throw_error (TLS_GENERIC_ERROR
,
1916 (("%s")), thread_db_err_str (err
));
1918 /* Cast assuming host == target. Joy. */
1919 /* Do proper sign extension for the target. */
1920 gdb_assert (exec_bfd
);
1921 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1922 ? (CORE_ADDR
) (intptr_t) address
1923 : (CORE_ADDR
) (uintptr_t) address
);
1926 beneath
= find_target_beneath (ops
);
1927 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1930 /* Implement the to_get_ada_task_ptid target method for this target. */
1933 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1935 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1936 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1940 thread_db_resume (struct target_ops
*ops
,
1941 ptid_t ptid
, int step
, enum gdb_signal signo
)
1943 struct target_ops
*beneath
= find_target_beneath (ops
);
1944 struct thread_db_info
*info
;
1946 if (ptid_equal (ptid
, minus_one_ptid
))
1947 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1949 info
= get_thread_db_info (ptid_get_pid (ptid
));
1951 /* This workaround is only needed for child fork lwps stopped in a
1952 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1953 workaround can be disabled. */
1955 info
->need_stale_parent_threads_check
= 0;
1957 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1960 /* qsort helper function for info_auto_load_libthread_db, sort the
1961 thread_db_info pointers primarily by their FILENAME and secondarily by their
1962 PID, both in ascending order. */
1965 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1967 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1968 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1971 retval
= strcmp (a
->filename
, b
->filename
);
1975 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1978 /* Implement 'info auto-load libthread-db'. */
1981 info_auto_load_libthread_db (char *args
, int from_tty
)
1983 struct ui_out
*uiout
= current_uiout
;
1984 const char *cs
= args
? args
: "";
1985 struct thread_db_info
*info
, **array
;
1986 unsigned info_count
, unique_filenames
;
1987 size_t max_filename_len
, max_pids_len
, pids_len
;
1988 struct cleanup
*back_to
;
1992 cs
= skip_spaces_const (cs
);
1994 error (_("'info auto-load libthread-db' does not accept any parameters"));
1997 for (info
= thread_db_list
; info
; info
= info
->next
)
1998 if (info
->filename
!= NULL
)
2001 array
= xmalloc (sizeof (*array
) * info_count
);
2002 back_to
= make_cleanup (xfree
, array
);
2005 for (info
= thread_db_list
; info
; info
= info
->next
)
2006 if (info
->filename
!= NULL
)
2007 array
[info_count
++] = info
;
2009 /* Sort ARRAY by filenames and PIDs. */
2011 qsort (array
, info_count
, sizeof (*array
),
2012 info_auto_load_libthread_db_compare
);
2014 /* Calculate the number of unique filenames (rows) and the maximum string
2015 length of PIDs list for the unique filenames (columns). */
2017 unique_filenames
= 0;
2018 max_filename_len
= 0;
2021 for (i
= 0; i
< info_count
; i
++)
2023 int pid
= array
[i
]->pid
;
2024 size_t this_pid_len
;
2026 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2029 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2032 max_filename_len
= max (max_filename_len
,
2033 strlen (array
[i
]->filename
));
2037 pids_len
-= strlen (", ");
2038 max_pids_len
= max (max_pids_len
, pids_len
);
2042 pids_len
+= this_pid_len
+ strlen (", ");
2046 pids_len
-= strlen (", ");
2047 max_pids_len
= max (max_pids_len
, pids_len
);
2050 /* Table header shifted right by preceding "libthread-db: " would not match
2052 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2053 ui_out_text (uiout
, "\n");
2055 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2056 "LinuxThreadDbTable");
2058 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2060 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2061 ui_out_table_body (uiout
);
2063 pids
= xmalloc (max_pids_len
+ 1);
2064 make_cleanup (xfree
, pids
);
2066 /* Note I is incremented inside the cycle, not at its end. */
2067 for (i
= 0; i
< info_count
;)
2069 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2073 ui_out_field_string (uiout
, "filename", info
->filename
);
2076 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2078 if (pids_end
!= pids
)
2083 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2084 "%u", array
[i
]->pid
);
2085 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2091 ui_out_field_string (uiout
, "pids", pids
);
2093 ui_out_text (uiout
, "\n");
2094 do_cleanups (chain
);
2097 do_cleanups (back_to
);
2099 if (info_count
== 0)
2100 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2104 init_thread_db_ops (void)
2106 thread_db_ops
.to_shortname
= "multi-thread";
2107 thread_db_ops
.to_longname
= "multi-threaded child process.";
2108 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2109 thread_db_ops
.to_detach
= thread_db_detach
;
2110 thread_db_ops
.to_wait
= thread_db_wait
;
2111 thread_db_ops
.to_resume
= thread_db_resume
;
2112 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2113 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2114 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2115 thread_db_ops
.to_stratum
= thread_stratum
;
2116 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2117 thread_db_ops
.to_get_thread_local_address
2118 = thread_db_get_thread_local_address
;
2119 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2120 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2121 thread_db_ops
.to_magic
= OPS_MAGIC
;
2123 complete_target_initialization (&thread_db_ops
);
2126 /* Provide a prototype to silence -Wmissing-prototypes. */
2127 extern initialize_file_ftype _initialize_thread_db
;
2130 _initialize_thread_db (void)
2132 init_thread_db_ops ();
2134 /* Defer loading of libthread_db.so until inferior is running.
2135 This allows gdb to load correct libthread_db for a given
2136 executable -- there could be mutiple versions of glibc,
2137 compiled with LinuxThreads or NPTL, and until there is
2138 a running inferior, we can't tell which libthread_db is
2139 the correct one to load. */
2141 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2143 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2145 &libthread_db_search_path
, _("\
2146 Set search path for libthread_db."), _("\
2147 Show the current search path or libthread_db."), _("\
2148 This path is used to search for libthread_db to be loaded into \
2150 Its value is a colon (':') separate list of directories to search.\n\
2151 Setting the search path to an empty list resets it to its default value."),
2152 set_libthread_db_search_path
,
2154 &setlist
, &showlist
);
2156 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2157 &libthread_db_debug
, _("\
2158 Set libthread-db debugging."), _("\
2159 Show libthread-db debugging."), _("\
2160 When non-zero, libthread-db debugging is enabled."),
2162 show_libthread_db_debug
,
2163 &setdebuglist
, &showdebuglist
);
2165 add_setshow_boolean_cmd ("libthread-db", class_support
,
2166 &auto_load_thread_db
, _("\
2167 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2168 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2169 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2170 locations to load libthread_db compatible with the inferior.\n\
2171 Standard system libthread_db still gets loaded even with this option off.\n\
2172 This options has security implications for untrusted inferiors."),
2173 NULL
, show_auto_load_thread_db
,
2174 auto_load_set_cmdlist_get (),
2175 auto_load_show_cmdlist_get ());
2177 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2178 _("Print the list of loaded inferior specific libthread_db.\n\
2179 Usage: info auto-load libthread-db"),
2180 auto_load_info_cmdlist_get ());
2182 /* Add ourselves to objfile event chain. */
2183 observer_attach_new_objfile (thread_db_new_objfile
);
2185 /* Add ourselves to inferior_created event chain.
2186 This is needed to handle debugging statically linked programs where
2187 the new_objfile observer won't get called for libpthread. */
2188 observer_attach_inferior_created (thread_db_inferior_created
);