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
)
614 volatile struct gdb_exception except
;
616 TRY_CATCH (except
, RETURN_MASK_ERROR
)
618 thread_db_find_new_threads_2 (ptid
, 1);
621 if (except
.reason
< 0)
623 if (libthread_db_debug
)
624 exception_fprintf (gdb_stdlog
, except
,
625 "Warning: thread_db_find_new_threads_silently: ");
627 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
628 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
629 where calls to td_thr_get_info fail with TD_ERR for statically linked
630 executables if td_thr_get_info is called before glibc has initialized
633 If the nptl bug is NOT present in the inferior and still thread_db
634 reports an error return 1. It means the inferior has corrupted thread
635 list and GDB should fall back only to LWPs.
637 If the nptl bug is present in the inferior return 0 to silently ignore
638 such errors, and let gdb enumerate threads again later. In such case
639 GDB cannot properly display LWPs if the inferior thread list is
640 corrupted. For core files it does not apply, no 'later enumeration'
643 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
645 exception_fprintf (gdb_stderr
, except
,
646 _("Warning: couldn't activate thread debugging "
647 "using libthread_db: "));
654 /* Lookup a library in which given symbol resides.
655 Note: this is looking in GDB process, not in the inferior.
656 Returns library name, or NULL. */
659 dladdr_to_soname (const void *addr
)
663 if (dladdr (addr
, &info
) != 0)
664 return info
.dli_fname
;
668 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
670 Failure could happen if libthread_db does not have symbols we expect,
671 or when it refuses to work with the current inferior (e.g. due to
672 version mismatch between libthread_db and libpthread). */
675 try_thread_db_load_1 (struct thread_db_info
*info
)
679 /* Initialize pointers to the dynamic library functions we will use.
680 Essential functions first. */
682 info
->td_init_p
= verbose_dlsym (info
->handle
, "td_init");
683 if (info
->td_init_p
== NULL
)
686 err
= info
->td_init_p ();
689 warning (_("Cannot initialize libthread_db: %s"),
690 thread_db_err_str (err
));
694 info
->td_ta_new_p
= verbose_dlsym (info
->handle
, "td_ta_new");
695 if (info
->td_ta_new_p
== NULL
)
698 /* Initialize the structure that identifies the child process. */
699 info
->proc_handle
.ptid
= inferior_ptid
;
701 /* Now attempt to open a connection to the thread library. */
702 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
705 if (libthread_db_debug
)
706 fprintf_unfiltered (gdb_stdlog
, _("td_ta_new failed: %s\n"),
707 thread_db_err_str (err
));
712 #ifdef THREAD_DB_HAS_TD_VERSION
715 /* The errors above are not unexpected and silently ignored:
716 they just mean we haven't found correct version of
720 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
725 info
->td_ta_map_id2thr_p
= verbose_dlsym (info
->handle
, "td_ta_map_id2thr");
726 if (info
->td_ta_map_id2thr_p
== NULL
)
729 info
->td_ta_map_lwp2thr_p
= verbose_dlsym (info
->handle
,
730 "td_ta_map_lwp2thr");
731 if (info
->td_ta_map_lwp2thr_p
== NULL
)
734 info
->td_ta_thr_iter_p
= verbose_dlsym (info
->handle
, "td_ta_thr_iter");
735 if (info
->td_ta_thr_iter_p
== NULL
)
738 info
->td_thr_validate_p
= verbose_dlsym (info
->handle
, "td_thr_validate");
739 if (info
->td_thr_validate_p
== NULL
)
742 info
->td_thr_get_info_p
= verbose_dlsym (info
->handle
, "td_thr_get_info");
743 if (info
->td_thr_get_info_p
== NULL
)
746 /* These are not essential. */
747 info
->td_ta_event_addr_p
= dlsym (info
->handle
, "td_ta_event_addr");
748 info
->td_ta_set_event_p
= dlsym (info
->handle
, "td_ta_set_event");
749 info
->td_ta_clear_event_p
= dlsym (info
->handle
, "td_ta_clear_event");
750 info
->td_ta_event_getmsg_p
= dlsym (info
->handle
, "td_ta_event_getmsg");
751 info
->td_thr_event_enable_p
= dlsym (info
->handle
, "td_thr_event_enable");
752 info
->td_thr_tls_get_addr_p
= dlsym (info
->handle
, "td_thr_tls_get_addr");
753 info
->td_thr_tlsbase_p
= dlsym (info
->handle
, "td_thr_tlsbase");
755 /* It's best to avoid td_ta_thr_iter if possible. That walks data
756 structures in the inferior's address space that may be corrupted,
757 or, if the target is running, may change while we walk them. If
758 there's execution (and /proc is mounted), then we're already
759 attached to all LWPs. Use thread_from_lwp, which uses
760 td_ta_map_lwp2thr instead, which does not walk the thread list.
762 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
763 currently on core targets, as it uses ptrace directly. */
764 if (target_has_execution
765 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid
)))
768 int pid
= ptid_get_pid (inferior_ptid
);
770 linux_stop_and_wait_all_lwps ();
773 if (ptid_get_pid (lp
->ptid
) == pid
)
774 thread_from_lwp (lp
->ptid
);
776 linux_unstop_all_lwps ();
778 else if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
780 /* Even if libthread_db initializes, if the thread list is
781 corrupted, we'd not manage to list any threads. Better reject this
782 thread_db, and fall back to at least listing LWPs. */
786 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
788 if (*libthread_db_search_path
|| libthread_db_debug
)
790 struct ui_file
*file
;
793 library
= dladdr_to_soname (*info
->td_ta_new_p
);
795 library
= LIBTHREAD_DB_SO
;
797 /* If we'd print this to gdb_stdout when debug output is
798 disabled, still print it to gdb_stdout if debug output is
799 enabled. User visible output should not depend on debug
801 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
802 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
806 /* The thread library was detected. Activate the thread_db target
807 if this is the first process using it. */
808 if (thread_db_list
->next
== NULL
)
809 push_target (&thread_db_ops
);
811 /* Enable event reporting, but not when debugging a core file. */
812 if (target_has_execution
&& thread_db_use_events ())
813 enable_thread_event_reporting ();
818 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
819 relative, or just LIBTHREAD_DB. */
822 try_thread_db_load (const char *library
, int check_auto_load_safe
)
825 struct thread_db_info
*info
;
827 if (libthread_db_debug
)
828 fprintf_unfiltered (gdb_stdlog
,
829 _("Trying host libthread_db library: %s.\n"),
832 if (check_auto_load_safe
)
834 if (access (library
, R_OK
) != 0)
836 /* Do not print warnings by file_is_auto_load_safe if the library does
837 not exist at this place. */
838 if (libthread_db_debug
)
839 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
840 safe_strerror (errno
));
844 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
845 "library \"%s\" from explicit "
851 handle
= dlopen (library
, RTLD_NOW
);
854 if (libthread_db_debug
)
855 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
859 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
863 td_init
= dlsym (handle
, "td_init");
866 const char *const libpath
= dladdr_to_soname (td_init
);
869 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
874 info
= add_thread_db_info (handle
);
876 /* Do not save system library name, that one is always trusted. */
877 if (strchr (library
, '/') != NULL
)
878 info
->filename
= gdb_realpath (library
);
880 if (try_thread_db_load_1 (info
))
883 /* This library "refused" to work on current inferior. */
884 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
888 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
889 Try loading libthread_db in directory(OBJ)/SUBDIR.
890 SUBDIR may be NULL. It may also be something like "../lib64".
891 The result is true for success. */
894 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
896 struct cleanup
*cleanup
;
899 const char *obj_name
= objfile_name (obj
);
901 if (obj_name
[0] != '/')
903 warning (_("Expected absolute pathname for libpthread in the"
904 " inferior, but got %s."), obj_name
);
908 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
909 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
910 cleanup
= make_cleanup (xfree
, path
);
912 strcpy (path
, obj_name
);
913 cp
= strrchr (path
, '/');
914 /* This should at minimum hit the first character. */
915 gdb_assert (cp
!= NULL
);
922 strcat (cp
, LIBTHREAD_DB_SO
);
924 result
= try_thread_db_load (path
, 1);
926 do_cleanups (cleanup
);
930 /* Handle $pdir in libthread-db-search-path.
931 Look for libthread_db in directory(libpthread)/SUBDIR.
932 SUBDIR may be NULL. It may also be something like "../lib64".
933 The result is true for success. */
936 try_thread_db_load_from_pdir (const char *subdir
)
940 if (!auto_load_thread_db
)
944 if (libpthread_name_p (objfile_name (obj
)))
946 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
949 /* We may have found the separate-debug-info version of
950 libpthread, and it may live in a directory without a matching
952 if (obj
->separate_debug_objfile_backlink
!= NULL
)
953 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
962 /* Handle $sdir in libthread-db-search-path.
963 Look for libthread_db in the system dirs, or wherever a plain
964 dlopen(file_without_path) will look.
965 The result is true for success. */
968 try_thread_db_load_from_sdir (void)
970 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
973 /* Try to load libthread_db from directory DIR of length DIR_LEN.
974 The result is true for success. */
977 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
979 struct cleanup
*cleanup
;
983 if (!auto_load_thread_db
)
986 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
987 cleanup
= make_cleanup (xfree
, path
);
989 memcpy (path
, dir
, dir_len
);
991 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
993 result
= try_thread_db_load (path
, 1);
995 do_cleanups (cleanup
);
999 /* Search libthread_db_search_path for libthread_db which "agrees"
1000 to work on current inferior.
1001 The result is true for success. */
1004 thread_db_load_search (void)
1006 VEC (char_ptr
) *dir_vec
;
1007 struct cleanup
*cleanups
;
1011 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
1012 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
1014 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
1016 const int pdir_len
= sizeof ("$pdir") - 1;
1017 size_t this_dir_len
;
1019 this_dir_len
= strlen (this_dir
);
1021 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
1022 && (this_dir
[pdir_len
] == '\0'
1023 || this_dir
[pdir_len
] == '/'))
1025 char *subdir
= NULL
;
1026 struct cleanup
*free_subdir_cleanup
1027 = make_cleanup (null_cleanup
, NULL
);
1029 if (this_dir
[pdir_len
] == '/')
1031 subdir
= xmalloc (strlen (this_dir
));
1032 make_cleanup (xfree
, subdir
);
1033 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1035 rc
= try_thread_db_load_from_pdir (subdir
);
1036 do_cleanups (free_subdir_cleanup
);
1040 else if (strcmp (this_dir
, "$sdir") == 0)
1042 if (try_thread_db_load_from_sdir ())
1050 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1058 do_cleanups (cleanups
);
1059 if (libthread_db_debug
)
1060 fprintf_unfiltered (gdb_stdlog
,
1061 _("thread_db_load_search returning %d\n"), rc
);
1065 /* Return non-zero if the inferior has a libpthread. */
1068 has_libpthread (void)
1070 struct objfile
*obj
;
1073 if (libpthread_name_p (objfile_name (obj
)))
1079 /* Attempt to load and initialize libthread_db.
1080 Return 1 on success. */
1083 thread_db_load (void)
1085 struct thread_db_info
*info
;
1087 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1092 /* Don't attempt to use thread_db on executables not running
1094 if (!target_has_registers
)
1097 /* Don't attempt to use thread_db for remote targets. */
1098 if (!(target_can_run (¤t_target
) || core_bfd
))
1101 if (thread_db_load_search ())
1104 /* We couldn't find a libthread_db.
1105 If the inferior has a libpthread warn the user. */
1106 if (has_libpthread ())
1108 warning (_("Unable to find libthread_db matching inferior's thread"
1109 " library, thread debugging will not be available."));
1113 /* Either this executable isn't using libpthread at all, or it is
1114 statically linked. Since we can't easily distinguish these two cases,
1115 no warning is issued. */
1120 disable_thread_event_reporting (struct thread_db_info
*info
)
1122 if (info
->td_ta_clear_event_p
!= NULL
)
1124 td_thr_events_t events
;
1126 /* Set the process wide mask saying we aren't interested in any
1128 td_event_fillset (&events
);
1129 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1132 info
->td_create_bp_addr
= 0;
1133 info
->td_death_bp_addr
= 0;
1137 check_thread_signals (void)
1139 if (!thread_signals
)
1144 lin_thread_get_thread_signals (&mask
);
1145 sigemptyset (&thread_stop_set
);
1146 sigemptyset (&thread_print_set
);
1148 for (i
= 1; i
< NSIG
; i
++)
1150 if (sigismember (&mask
, i
))
1152 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1153 sigaddset (&thread_stop_set
, i
);
1154 if (signal_print_update (gdb_signal_from_host (i
), 0))
1155 sigaddset (&thread_print_set
, i
);
1162 /* Check whether thread_db is usable. This function is called when
1163 an inferior is created (or otherwise acquired, e.g. attached to)
1164 and when new shared libraries are loaded into a running process. */
1167 check_for_thread_db (void)
1169 /* Do nothing if we couldn't load libthread_db.so.1. */
1170 if (!thread_db_load ())
1174 /* This function is called via the new_objfile observer. */
1177 thread_db_new_objfile (struct objfile
*objfile
)
1179 /* This observer must always be called with inferior_ptid set
1183 /* libpthread with separate debug info has its debug info file already
1184 loaded (and notified without successful thread_db initialization)
1185 the time observer_notify_new_objfile is called for the library itself.
1186 Static executables have their separate debug info loaded already
1187 before the inferior has started. */
1188 && objfile
->separate_debug_objfile_backlink
== NULL
1189 /* Only check for thread_db if we loaded libpthread,
1190 or if this is the main symbol file.
1191 We need to check OBJF_MAINLINE to handle the case of debugging
1192 a statically linked executable AND the symbol file is specified AFTER
1193 the exec file is loaded (e.g., gdb -c core ; file foo).
1194 For dynamically linked executables, libpthread can be near the end
1195 of the list of shared libraries to load, and in an app of several
1196 thousand shared libraries, this can otherwise be painful. */
1197 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1198 || libpthread_name_p (objfile_name (objfile
))))
1199 check_for_thread_db ();
1203 check_pid_namespace_match (void)
1205 /* Check is only relevant for local targets targets. */
1206 if (target_can_run (¤t_target
))
1208 /* If the child is in a different PID namespace, its idea of its
1209 PID will differ from our idea of its PID. When we scan the
1210 child's thread list, we'll mistakenly think it has no threads
1211 since the thread PID fields won't match the PID we give to
1213 char *our_pid_ns
= linux_proc_pid_get_ns (getpid (), "pid");
1214 char *inferior_pid_ns
= linux_proc_pid_get_ns (
1215 ptid_get_pid (inferior_ptid
), "pid");
1217 if (our_pid_ns
!= NULL
&& inferior_pid_ns
!= NULL
1218 && strcmp (our_pid_ns
, inferior_pid_ns
) != 0)
1220 warning (_ ("Target and debugger are in different PID "
1221 "namespaces; thread lists and other data are "
1222 "likely unreliable"));
1226 xfree (inferior_pid_ns
);
1230 /* This function is called via the inferior_created observer.
1231 This handles the case of debugging statically linked executables. */
1234 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1236 check_pid_namespace_match ();
1237 check_for_thread_db ();
1240 /* Update the thread's state (what's displayed in "info threads"),
1241 from libthread_db thread state information. */
1244 update_thread_state (struct private_thread_info
*priv
,
1245 const td_thrinfo_t
*ti_p
)
1247 priv
->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1248 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1251 /* Attach to a new thread. This function is called when we receive a
1252 TD_CREATE event or when we iterate over all threads and find one
1253 that wasn't already in our list. Returns true on success. */
1256 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1257 const td_thrinfo_t
*ti_p
)
1259 struct thread_info
*tp
;
1260 struct thread_db_info
*info
;
1262 /* If we're being called after a TD_CREATE event, we may already
1263 know about this thread. There are two ways this can happen. We
1264 may have iterated over all threads between the thread creation
1265 and the TD_CREATE event, for instance when the user has issued
1266 the `info threads' command before the SIGTRAP for hitting the
1267 thread creation breakpoint was reported. Alternatively, the
1268 thread may have exited and a new one been created with the same
1269 thread ID. In the first case we don't need to do anything; in
1270 the second case we should discard information about the dead
1271 thread and attach to the new one. */
1272 tp
= find_thread_ptid (ptid
);
1275 /* If tp->priv is NULL, then GDB is already attached to this
1276 thread, but we do not know anything about it. We can learn
1277 about it here. This can only happen if we have some other
1278 way besides libthread_db to notice new threads (i.e.
1279 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1280 exit, so this can not be a stale thread recreated with the
1282 if (tp
->priv
!= NULL
)
1284 if (!tp
->priv
->dying
)
1287 delete_thread (ptid
);
1292 /* Under GNU/Linux, we have to attach to each and every thread. */
1293 if (target_has_execution
1298 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1302 /* Error, stop iterating. */
1307 /* Pretend this thread doesn't exist yet, and keep
1312 /* Otherwise, we sucessfully attached to the thread. */
1315 info
= get_thread_db_info (ptid_get_pid (ptid
));
1316 record_thread (info
, tp
, ptid
, th_p
, ti_p
);
1320 /* Record a new thread in GDB's thread list. Creates the thread's
1321 private info. If TP is NULL, creates a new thread. Otherwise,
1325 record_thread (struct thread_db_info
*info
,
1326 struct thread_info
*tp
,
1327 ptid_t ptid
, const td_thrhandle_t
*th_p
,
1328 const td_thrinfo_t
*ti_p
)
1331 struct private_thread_info
*priv
;
1332 int new_thread
= (tp
== NULL
);
1334 /* A thread ID of zero may mean the thread library has not
1335 initialized yet. Leave private == NULL until the thread library
1337 if (ti_p
->ti_tid
== 0)
1340 /* Construct the thread's private data. */
1341 priv
= xmalloc (sizeof (struct private_thread_info
));
1342 memset (priv
, 0, sizeof (struct private_thread_info
));
1345 priv
->tid
= ti_p
->ti_tid
;
1346 update_thread_state (priv
, ti_p
);
1348 /* Add the thread to GDB's thread list. */
1350 tp
= add_thread_with_info (ptid
, priv
);
1354 /* Enable thread event reporting for this thread, except when
1355 debugging a core file. */
1356 if (target_has_execution
&& thread_db_use_events () && new_thread
)
1358 err
= info
->td_thr_event_enable_p (th_p
, 1);
1360 error (_("Cannot enable thread event reporting for %s: %s"),
1361 target_pid_to_str (ptid
), thread_db_err_str (err
));
1364 if (target_has_execution
)
1365 check_thread_signals ();
1369 detach_thread (ptid_t ptid
)
1371 struct thread_info
*thread_info
;
1373 /* Don't delete the thread now, because it still reports as active
1374 until it has executed a few instructions after the event
1375 breakpoint - if we deleted it now, "info threads" would cause us
1376 to re-attach to it. Just mark it as having had a TD_DEATH
1377 event. This means that we won't delete it from our thread list
1378 until we notice that it's dead (via prune_threads), or until
1379 something re-uses its thread ID. We'll report the thread exit
1380 when the underlying LWP dies. */
1381 thread_info
= find_thread_ptid (ptid
);
1382 gdb_assert (thread_info
!= NULL
&& thread_info
->priv
!= NULL
);
1383 thread_info
->priv
->dying
= 1;
1387 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1389 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1390 struct thread_db_info
*info
;
1392 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1396 if (target_has_execution
&& thread_db_use_events ())
1398 disable_thread_event_reporting (info
);
1400 /* Delete the old thread event breakpoints. Note that
1401 unlike when mourning, we can remove them here because
1402 there's still a live inferior to poke at. In any case,
1403 GDB will not try to insert anything in the inferior when
1404 removing a breakpoint. */
1405 remove_thread_event_breakpoints ();
1408 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1411 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1413 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1415 /* If there are no more processes using libpthread, detach the
1416 thread_db target ops. */
1417 if (!thread_db_list
)
1418 unpush_target (&thread_db_ops
);
1421 /* Check if PID is currently stopped at the location of a thread event
1422 breakpoint location. If it is, read the event message and act upon
1426 check_event (ptid_t ptid
)
1428 struct regcache
*regcache
= get_thread_regcache (ptid
);
1429 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1435 struct thread_db_info
*info
;
1437 info
= get_thread_db_info (ptid_get_pid (ptid
));
1439 /* Bail out early if we're not at a thread event breakpoint. */
1440 stop_pc
= regcache_read_pc (regcache
);
1441 if (!target_supports_stopped_by_sw_breakpoint ())
1442 stop_pc
-= gdbarch_decr_pc_after_break (gdbarch
);
1444 if (stop_pc
!= info
->td_create_bp_addr
1445 && stop_pc
!= info
->td_death_bp_addr
)
1448 /* Access an lwp we know is stopped. */
1449 info
->proc_handle
.ptid
= ptid
;
1451 /* If we have only looked at the first thread before libpthread was
1452 initialized, we may not know its thread ID yet. Make sure we do
1453 before we add another thread to the list. */
1454 if (!have_threads (ptid
))
1455 thread_db_find_new_threads_1 (ptid
);
1457 /* If we are at a create breakpoint, we do not know what new lwp
1458 was created and cannot specifically locate the event message for it.
1459 We have to call td_ta_event_getmsg() to get
1460 the latest message. Since we have no way of correlating whether
1461 the event message we get back corresponds to our breakpoint, we must
1462 loop and read all event messages, processing them appropriately.
1463 This guarantees we will process the correct message before continuing
1464 from the breakpoint.
1466 Currently, death events are not enabled. If they are enabled,
1467 the death event can use the td_thr_event_getmsg() interface to
1468 get the message specifically for that lwp and avoid looping
1475 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1478 if (err
== TD_NOMSG
)
1481 error (_("Cannot get thread event message: %s"),
1482 thread_db_err_str (err
));
1485 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1487 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1489 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1494 /* Call attach_thread whether or not we already know about a
1495 thread with this thread ID. */
1496 attach_thread (ptid
, msg
.th_p
, &ti
);
1502 if (!in_thread_list (ptid
))
1503 error (_("Spurious thread death event."));
1505 detach_thread (ptid
);
1510 error (_("Spurious thread event."));
1517 thread_db_wait (struct target_ops
*ops
,
1518 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1521 struct thread_db_info
*info
;
1522 struct target_ops
*beneath
= find_target_beneath (ops
);
1524 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1526 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1529 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1530 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1533 info
= get_thread_db_info (ptid_get_pid (ptid
));
1535 /* If this process isn't using thread_db, we're done. */
1539 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1541 /* New image, it may or may not end up using thread_db. Assume
1542 not unless we find otherwise. */
1543 delete_thread_db_info (ptid_get_pid (ptid
));
1544 if (!thread_db_list
)
1545 unpush_target (&thread_db_ops
);
1547 /* Thread event breakpoints are deleted by
1548 update_breakpoints_after_exec. */
1553 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1554 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1555 /* Check for a thread event. */
1558 /* Fill in the thread's user-level thread id and status. */
1559 thread_from_lwp (ptid
);
1565 thread_db_mourn_inferior (struct target_ops
*ops
)
1567 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1569 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1571 target_beneath
->to_mourn_inferior (target_beneath
);
1573 /* Delete the old thread event breakpoints. Do this after mourning
1574 the inferior, so that we don't try to uninsert them. */
1575 remove_thread_event_breakpoints ();
1577 /* Detach thread_db target ops. */
1578 if (!thread_db_list
)
1579 unpush_target (ops
);
1582 struct callback_data
1584 struct thread_db_info
*info
;
1589 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1594 struct thread_info
*tp
;
1595 struct callback_data
*cb_data
= data
;
1596 struct thread_db_info
*info
= cb_data
->info
;
1598 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1600 error (_("find_new_threads_callback: cannot get thread info: %s"),
1601 thread_db_err_str (err
));
1603 if (ti
.ti_lid
== -1)
1605 /* A thread with kernel thread ID -1 is either a thread that
1606 exited and was joined, or a thread that is being created but
1607 hasn't started yet, and that is reusing the tcb/stack of a
1608 thread that previously exited and was joined. (glibc marks
1609 terminated and joined threads with kernel thread ID -1. See
1611 if (libthread_db_debug
)
1612 fprintf_unfiltered (gdb_stdlog
,
1613 "thread_db: skipping exited and "
1614 "joined thread (0x%lx)\n", ti
.ti_tid
);
1620 /* A thread ID of zero means that this is the main thread, but
1621 glibc has not yet initialized thread-local storage and the
1622 pthread library. We do not know what the thread's TID will
1623 be yet. Just enable event reporting and otherwise ignore
1626 /* In that case, we're not stopped in a fork syscall and don't
1627 need this glibc bug workaround. */
1628 info
->need_stale_parent_threads_check
= 0;
1630 if (target_has_execution
&& thread_db_use_events ())
1632 err
= info
->td_thr_event_enable_p (th_p
, 1);
1634 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1635 (int) ti
.ti_lid
, thread_db_err_str (err
));
1641 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1642 bit expensive, as it needs to open /proc/pid/status, so try to
1643 avoid doing the work if we know we don't have to. */
1644 if (info
->need_stale_parent_threads_check
)
1646 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1648 if (tgid
!= -1 && tgid
!= info
->pid
)
1652 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1653 tp
= find_thread_ptid (ptid
);
1654 if (tp
== NULL
|| tp
->priv
== NULL
)
1656 if (attach_thread (ptid
, th_p
, &ti
))
1657 cb_data
->new_threads
+= 1;
1659 /* Problem attaching this thread; perhaps it exited before we
1661 This could mean that the thread list inside glibc itself is in
1662 inconsistent state, and libthread_db could go on looping forever
1663 (observed with glibc-2.3.6). To prevent that, terminate
1664 iteration: thread_db_find_new_threads_2 will retry. */
1667 else if (target_has_execution
&& !thread_db_use_events ())
1669 /* Need to update this if not using the libthread_db events
1670 (particularly, the TD_DEATH event). */
1671 update_thread_state (tp
->priv
, &ti
);
1677 /* Helper for thread_db_find_new_threads_2.
1678 Returns number of new threads found. */
1681 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1684 volatile struct gdb_exception except
;
1685 struct callback_data data
;
1686 td_err_e err
= TD_ERR
;
1689 data
.new_threads
= 0;
1691 /* See comment in thread_db_update_thread_list. */
1692 gdb_assert (!target_has_execution
|| thread_db_use_events ());
1694 TRY_CATCH (except
, RETURN_MASK_ERROR
)
1696 /* Iterate over all user-space threads to discover new threads. */
1697 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1698 find_new_threads_callback
,
1701 TD_THR_LOWEST_PRIORITY
,
1703 TD_THR_ANY_USER_FLAGS
);
1706 if (libthread_db_debug
)
1708 if (except
.reason
< 0)
1709 exception_fprintf (gdb_stdlog
, except
,
1710 "Warning: find_new_threads_once: ");
1712 fprintf_unfiltered (gdb_stdlog
,
1713 _("Found %d new threads in iteration %d.\n"),
1714 data
.new_threads
, iteration
);
1720 return data
.new_threads
;
1723 /* Search for new threads, accessing memory through stopped thread
1724 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1725 searches in a row do not discover any new threads. */
1728 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1730 td_err_e err
= TD_OK
;
1731 struct thread_db_info
*info
;
1734 info
= get_thread_db_info (ptid_get_pid (ptid
));
1736 /* Access an lwp we know is stopped. */
1737 info
->proc_handle
.ptid
= ptid
;
1741 /* Require 4 successive iterations which do not find any new threads.
1742 The 4 is a heuristic: there is an inherent race here, and I have
1743 seen that 2 iterations in a row are not always sufficient to
1744 "capture" all threads. */
1745 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1746 if (find_new_threads_once (info
, i
, &err
) != 0)
1748 /* Found some new threads. Restart the loop from beginning. */
1753 find_new_threads_once (info
, 0, &err
);
1756 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1760 thread_db_find_new_threads_1 (ptid_t ptid
)
1762 thread_db_find_new_threads_2 (ptid
, 0);
1766 update_thread_core (struct lwp_info
*info
, void *closure
)
1768 info
->core
= linux_common_core_of_thread (info
->ptid
);
1772 /* Update the thread list using td_ta_thr_iter. */
1775 thread_db_update_thread_list_td_ta_thr_iter (struct target_ops
*ops
)
1777 struct thread_db_info
*info
;
1778 struct inferior
*inf
;
1784 struct thread_info
*thread
;
1789 info
= get_thread_db_info (inf
->pid
);
1793 thread
= any_live_thread_of_process (inf
->pid
);
1794 if (thread
== NULL
|| thread
->executing
)
1797 thread_db_find_new_threads_1 (thread
->ptid
);
1801 /* Implement the to_update_thread_list target method for this
1805 thread_db_update_thread_list (struct target_ops
*ops
)
1807 /* It's best to avoid td_ta_thr_iter if possible. That walks data
1808 structures in the inferior's address space that may be corrupted,
1809 or, if the target is running, the list may change while we walk
1810 it. In the latter case, it's possible that a thread exits just
1811 at the exact time that causes GDB to get stuck in an infinite
1812 loop. To avoid pausing all threads whenever the core wants to
1813 refresh the thread list, if the kernel supports clone events
1814 (meaning we're always already attached to all LWPs), we use
1815 thread_from_lwp immediately when we see an LWP stop. That uses
1816 thread_db entry points that do not walk libpthread's thread list,
1817 so should be safe, as well as more efficient. */
1818 if (target_has_execution
&& !thread_db_use_events ())
1819 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1821 thread_db_update_thread_list_td_ta_thr_iter (ops
);
1823 if (target_has_execution
)
1824 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1825 update_thread_core
, NULL
);
1829 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1831 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1832 struct target_ops
*beneath
;
1834 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1836 static char buf
[64];
1839 tid
= thread_info
->priv
->tid
;
1840 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1841 tid
, ptid_get_lwp (ptid
));
1846 beneath
= find_target_beneath (ops
);
1847 return beneath
->to_pid_to_str (beneath
, ptid
);
1850 /* Return a string describing the state of the thread specified by
1854 thread_db_extra_thread_info (struct target_ops
*self
,
1855 struct thread_info
*info
)
1857 if (info
->priv
== NULL
)
1860 if (info
->priv
->dying
)
1866 /* Get the address of the thread local variable in load module LM which
1867 is stored at OFFSET within the thread local storage for thread PTID. */
1870 thread_db_get_thread_local_address (struct target_ops
*ops
,
1875 struct thread_info
*thread_info
;
1876 struct target_ops
*beneath
;
1878 /* If we have not discovered any threads yet, check now. */
1879 if (!have_threads (ptid
))
1880 thread_db_find_new_threads_1 (ptid
);
1882 /* Find the matching thread. */
1883 thread_info
= find_thread_ptid (ptid
);
1885 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1889 struct thread_db_info
*info
;
1891 info
= get_thread_db_info (ptid_get_pid (ptid
));
1893 /* Finally, get the address of the variable. */
1896 /* glibc doesn't provide the needed interface. */
1897 if (!info
->td_thr_tls_get_addr_p
)
1898 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1899 _("No TLS library support"));
1901 /* Note the cast through uintptr_t: this interface only works if
1902 a target address fits in a psaddr_t, which is a host pointer.
1903 So a 32-bit debugger can not access 64-bit TLS through this. */
1904 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1905 (psaddr_t
)(uintptr_t) lm
,
1910 /* If glibc doesn't provide the needed interface throw an error
1911 that LM is zero - normally cases it should not be. */
1912 if (!info
->td_thr_tlsbase_p
)
1913 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1914 _("TLS load module not found"));
1916 /* This code path handles the case of -static -pthread executables:
1917 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1918 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1919 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1920 The constant number 1 depends on GNU __libc_setup_tls
1921 initialization of l_tls_modid to 1. */
1922 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1924 address
= (char *) address
+ offset
;
1927 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1928 /* The memory hasn't been allocated, yet. */
1929 if (err
== TD_NOTALLOC
)
1930 /* Now, if libthread_db provided the initialization image's
1931 address, we *could* try to build a non-lvalue value from
1932 the initialization image. */
1933 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1934 _("TLS not allocated yet"));
1937 /* Something else went wrong. */
1939 throw_error (TLS_GENERIC_ERROR
,
1940 (("%s")), thread_db_err_str (err
));
1942 /* Cast assuming host == target. Joy. */
1943 /* Do proper sign extension for the target. */
1944 gdb_assert (exec_bfd
);
1945 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1946 ? (CORE_ADDR
) (intptr_t) address
1947 : (CORE_ADDR
) (uintptr_t) address
);
1950 beneath
= find_target_beneath (ops
);
1951 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1954 /* Implement the to_get_ada_task_ptid target method for this target. */
1957 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1959 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1960 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1964 thread_db_resume (struct target_ops
*ops
,
1965 ptid_t ptid
, int step
, enum gdb_signal signo
)
1967 struct target_ops
*beneath
= find_target_beneath (ops
);
1968 struct thread_db_info
*info
;
1970 if (ptid_equal (ptid
, minus_one_ptid
))
1971 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1973 info
= get_thread_db_info (ptid_get_pid (ptid
));
1975 /* This workaround is only needed for child fork lwps stopped in a
1976 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1977 workaround can be disabled. */
1979 info
->need_stale_parent_threads_check
= 0;
1981 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1984 /* qsort helper function for info_auto_load_libthread_db, sort the
1985 thread_db_info pointers primarily by their FILENAME and secondarily by their
1986 PID, both in ascending order. */
1989 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1991 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1992 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1995 retval
= strcmp (a
->filename
, b
->filename
);
1999 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
2002 /* Implement 'info auto-load libthread-db'. */
2005 info_auto_load_libthread_db (char *args
, int from_tty
)
2007 struct ui_out
*uiout
= current_uiout
;
2008 const char *cs
= args
? args
: "";
2009 struct thread_db_info
*info
, **array
;
2010 unsigned info_count
, unique_filenames
;
2011 size_t max_filename_len
, max_pids_len
, pids_len
;
2012 struct cleanup
*back_to
;
2016 cs
= skip_spaces_const (cs
);
2018 error (_("'info auto-load libthread-db' does not accept any parameters"));
2021 for (info
= thread_db_list
; info
; info
= info
->next
)
2022 if (info
->filename
!= NULL
)
2025 array
= xmalloc (sizeof (*array
) * info_count
);
2026 back_to
= make_cleanup (xfree
, array
);
2029 for (info
= thread_db_list
; info
; info
= info
->next
)
2030 if (info
->filename
!= NULL
)
2031 array
[info_count
++] = info
;
2033 /* Sort ARRAY by filenames and PIDs. */
2035 qsort (array
, info_count
, sizeof (*array
),
2036 info_auto_load_libthread_db_compare
);
2038 /* Calculate the number of unique filenames (rows) and the maximum string
2039 length of PIDs list for the unique filenames (columns). */
2041 unique_filenames
= 0;
2042 max_filename_len
= 0;
2045 for (i
= 0; i
< info_count
; i
++)
2047 int pid
= array
[i
]->pid
;
2048 size_t this_pid_len
;
2050 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2053 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2056 max_filename_len
= max (max_filename_len
,
2057 strlen (array
[i
]->filename
));
2061 pids_len
-= strlen (", ");
2062 max_pids_len
= max (max_pids_len
, pids_len
);
2066 pids_len
+= this_pid_len
+ strlen (", ");
2070 pids_len
-= strlen (", ");
2071 max_pids_len
= max (max_pids_len
, pids_len
);
2074 /* Table header shifted right by preceding "libthread-db: " would not match
2076 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2077 ui_out_text (uiout
, "\n");
2079 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2080 "LinuxThreadDbTable");
2082 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2084 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2085 ui_out_table_body (uiout
);
2087 pids
= xmalloc (max_pids_len
+ 1);
2088 make_cleanup (xfree
, pids
);
2090 /* Note I is incremented inside the cycle, not at its end. */
2091 for (i
= 0; i
< info_count
;)
2093 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2097 ui_out_field_string (uiout
, "filename", info
->filename
);
2100 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2102 if (pids_end
!= pids
)
2107 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2108 "%u", array
[i
]->pid
);
2109 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2115 ui_out_field_string (uiout
, "pids", pids
);
2117 ui_out_text (uiout
, "\n");
2118 do_cleanups (chain
);
2121 do_cleanups (back_to
);
2123 if (info_count
== 0)
2124 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2128 init_thread_db_ops (void)
2130 thread_db_ops
.to_shortname
= "multi-thread";
2131 thread_db_ops
.to_longname
= "multi-threaded child process.";
2132 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2133 thread_db_ops
.to_detach
= thread_db_detach
;
2134 thread_db_ops
.to_wait
= thread_db_wait
;
2135 thread_db_ops
.to_resume
= thread_db_resume
;
2136 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2137 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2138 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2139 thread_db_ops
.to_stratum
= thread_stratum
;
2140 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2141 thread_db_ops
.to_get_thread_local_address
2142 = thread_db_get_thread_local_address
;
2143 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2144 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2145 thread_db_ops
.to_magic
= OPS_MAGIC
;
2147 complete_target_initialization (&thread_db_ops
);
2150 /* Provide a prototype to silence -Wmissing-prototypes. */
2151 extern initialize_file_ftype _initialize_thread_db
;
2154 _initialize_thread_db (void)
2156 init_thread_db_ops ();
2158 /* Defer loading of libthread_db.so until inferior is running.
2159 This allows gdb to load correct libthread_db for a given
2160 executable -- there could be mutiple versions of glibc,
2161 compiled with LinuxThreads or NPTL, and until there is
2162 a running inferior, we can't tell which libthread_db is
2163 the correct one to load. */
2165 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2167 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2169 &libthread_db_search_path
, _("\
2170 Set search path for libthread_db."), _("\
2171 Show the current search path or libthread_db."), _("\
2172 This path is used to search for libthread_db to be loaded into \
2174 Its value is a colon (':') separate list of directories to search.\n\
2175 Setting the search path to an empty list resets it to its default value."),
2176 set_libthread_db_search_path
,
2178 &setlist
, &showlist
);
2180 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2181 &libthread_db_debug
, _("\
2182 Set libthread-db debugging."), _("\
2183 Show libthread-db debugging."), _("\
2184 When non-zero, libthread-db debugging is enabled."),
2186 show_libthread_db_debug
,
2187 &setdebuglist
, &showdebuglist
);
2189 add_setshow_boolean_cmd ("libthread-db", class_support
,
2190 &auto_load_thread_db
, _("\
2191 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2192 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2193 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2194 locations to load libthread_db compatible with the inferior.\n\
2195 Standard system libthread_db still gets loaded even with this option off.\n\
2196 This options has security implications for untrusted inferiors."),
2197 NULL
, show_auto_load_thread_db
,
2198 auto_load_set_cmdlist_get (),
2199 auto_load_show_cmdlist_get ());
2201 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2202 _("Print the list of loaded inferior specific libthread_db.\n\
2203 Usage: info auto-load libthread-db"),
2204 auto_load_info_cmdlist_get ());
2206 /* Add ourselves to objfile event chain. */
2207 observer_attach_new_objfile (thread_db_new_objfile
);
2209 /* Add ourselves to inferior_created event chain.
2210 This is needed to handle debugging statically linked programs where
2211 the new_objfile observer won't get called for libpthread. */
2212 observer_attach_inferior_created (thread_db_inferior_created
);