1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2001, 2003-2012 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_assert.h"
24 #include "gdb_proc_service.h"
25 #include "gdb_thread_db.h"
29 #include "exceptions.h"
31 #include "gdbthread.h"
38 #include "solib-svr4.h"
41 #include "linux-nat.h"
42 #include "linux-procfs.h"
43 #include "linux-osdata.h"
44 #include "auto-load.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 /* "show" command for the auto_load_thread_db configuration variable. */
84 show_auto_load_thread_db (struct ui_file
*file
, int from_tty
,
85 struct cmd_list_element
*c
, const char *value
)
87 fprintf_filtered (file
, _("Auto-loading of inferior specific libthread_db "
93 set_libthread_db_search_path (char *ignored
, int from_tty
,
94 struct cmd_list_element
*c
)
96 if (*libthread_db_search_path
== '\0')
98 xfree (libthread_db_search_path
);
99 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
103 /* If non-zero, print details of libthread_db processing. */
105 static int libthread_db_debug
;
108 show_libthread_db_debug (struct ui_file
*file
, int from_tty
,
109 struct cmd_list_element
*c
, const char *value
)
111 fprintf_filtered (file
, _("libthread-db debugging is %s.\n"), value
);
114 /* If we're running on GNU/Linux, we must explicitly attach to any new
117 /* This module's target vector. */
118 static struct target_ops thread_db_ops
;
120 /* Non-zero if we have determined the signals used by the threads
122 static int thread_signals
;
123 static sigset_t thread_stop_set
;
124 static sigset_t thread_print_set
;
126 struct thread_db_info
128 struct thread_db_info
*next
;
130 /* Process id this object refers to. */
133 /* Handle from dlopen for libthread_db.so. */
136 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
137 HANDLE. It may be NULL for system library. */
140 /* Structure that identifies the child process for the
141 <proc_service.h> interface. */
142 struct ps_prochandle proc_handle
;
144 /* Connection to the libthread_db library. */
145 td_thragent_t
*thread_agent
;
147 /* True if we need to apply the workaround for glibc/BZ5983. When
148 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
149 list, nptl_db returns the parent's threads in addition to the new
150 (single) child thread. If this flag is set, we do extra work to
151 be able to ignore such stale entries. */
152 int need_stale_parent_threads_check
;
154 /* Location of the thread creation event breakpoint. The code at
155 this location in the child process will be called by the pthread
156 library whenever a new thread is created. By setting a special
157 breakpoint at this location, GDB can detect when a new thread is
158 created. We obtain this location via the td_ta_event_addr
160 CORE_ADDR td_create_bp_addr
;
162 /* Location of the thread death event breakpoint. */
163 CORE_ADDR td_death_bp_addr
;
165 /* Pointers to the libthread_db functions. */
167 td_err_e (*td_init_p
) (void);
169 td_err_e (*td_ta_new_p
) (struct ps_prochandle
* ps
,
171 td_err_e (*td_ta_map_id2thr_p
) (const td_thragent_t
*ta
, thread_t pt
,
172 td_thrhandle_t
*__th
);
173 td_err_e (*td_ta_map_lwp2thr_p
) (const td_thragent_t
*ta
,
174 lwpid_t lwpid
, td_thrhandle_t
*th
);
175 td_err_e (*td_ta_thr_iter_p
) (const td_thragent_t
*ta
,
176 td_thr_iter_f
*callback
, void *cbdata_p
,
177 td_thr_state_e state
, int ti_pri
,
178 sigset_t
*ti_sigmask_p
,
179 unsigned int ti_user_flags
);
180 td_err_e (*td_ta_event_addr_p
) (const td_thragent_t
*ta
,
181 td_event_e event
, td_notify_t
*ptr
);
182 td_err_e (*td_ta_set_event_p
) (const td_thragent_t
*ta
,
183 td_thr_events_t
*event
);
184 td_err_e (*td_ta_clear_event_p
) (const td_thragent_t
*ta
,
185 td_thr_events_t
*event
);
186 td_err_e (*td_ta_event_getmsg_p
) (const td_thragent_t
*ta
,
187 td_event_msg_t
*msg
);
189 td_err_e (*td_thr_validate_p
) (const td_thrhandle_t
*th
);
190 td_err_e (*td_thr_get_info_p
) (const td_thrhandle_t
*th
,
191 td_thrinfo_t
*infop
);
192 td_err_e (*td_thr_event_enable_p
) (const td_thrhandle_t
*th
,
195 td_err_e (*td_thr_tls_get_addr_p
) (const td_thrhandle_t
*th
,
196 psaddr_t map_address
,
197 size_t offset
, psaddr_t
*address
);
200 /* List of known processes using thread_db, and the required
202 struct thread_db_info
*thread_db_list
;
204 static void thread_db_find_new_threads_1 (ptid_t ptid
);
205 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
207 /* Add the current inferior to the list of processes using libpthread.
208 Return a pointer to the newly allocated object that was added to
209 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
212 static struct thread_db_info
*
213 add_thread_db_info (void *handle
)
215 struct thread_db_info
*info
;
217 info
= xcalloc (1, sizeof (*info
));
218 info
->pid
= ptid_get_pid (inferior_ptid
);
219 info
->handle
= handle
;
221 /* The workaround works by reading from /proc/pid/status, so it is
222 disabled for core files. */
223 if (target_has_execution
)
224 info
->need_stale_parent_threads_check
= 1;
226 info
->next
= thread_db_list
;
227 thread_db_list
= info
;
232 /* Return the thread_db_info object representing the bookkeeping
233 related to process PID, if any; NULL otherwise. */
235 static struct thread_db_info
*
236 get_thread_db_info (int pid
)
238 struct thread_db_info
*info
;
240 for (info
= thread_db_list
; info
; info
= info
->next
)
241 if (pid
== info
->pid
)
247 /* When PID has exited or has been detached, we no longer want to keep
248 track of it as using libpthread. Call this function to discard
249 thread_db related info related to PID. Note that this closes
250 LIBTHREAD_DB_SO's dlopen'ed handle. */
253 delete_thread_db_info (int pid
)
255 struct thread_db_info
*info
, *info_prev
;
259 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
260 if (pid
== info
->pid
)
266 if (info
->handle
!= NULL
)
267 dlclose (info
->handle
);
269 xfree (info
->filename
);
272 info_prev
->next
= info
->next
;
274 thread_db_list
= info
->next
;
279 /* Prototypes for local functions. */
280 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
281 const td_thrinfo_t
*ti_p
);
282 static void detach_thread (ptid_t ptid
);
285 /* Use "struct private_thread_info" to cache thread state. This is
286 a substantial optimization. */
288 struct private_thread_info
290 /* Flag set when we see a TD_DEATH event for this thread. */
291 unsigned int dying
:1;
293 /* Cached thread state. */
300 thread_db_err_str (td_err_e err
)
307 return "generic 'call succeeded'";
309 return "generic error";
311 return "no thread to satisfy query";
313 return "no sync handle to satisfy query";
315 return "no LWP to satisfy query";
317 return "invalid process handle";
319 return "invalid thread handle";
321 return "invalid synchronization handle";
323 return "invalid thread agent";
325 return "invalid key";
327 return "no event message for getmsg";
329 return "FPU register set not available";
331 return "application not linked with libthread";
333 return "requested event is not supported";
335 return "capability not available";
337 return "debugger service failed";
339 return "operation not applicable to";
341 return "no thread-specific data for this thread";
343 return "malloc failed";
345 return "only part of register set was written/read";
347 return "X register set not available for this thread";
348 #ifdef THREAD_DB_HAS_TD_NOTALLOC
350 return "thread has not yet allocated TLS for given module";
352 #ifdef THREAD_DB_HAS_TD_VERSION
354 return "versions of libpthread and libthread_db do not match";
356 #ifdef THREAD_DB_HAS_TD_NOTLS
358 return "there is no TLS segment in the given module";
361 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
366 /* Return 1 if any threads have been registered. There may be none if
367 the threading library is not fully initialized yet. */
370 have_threads_callback (struct thread_info
*thread
, void *args
)
372 int pid
= * (int *) args
;
374 if (ptid_get_pid (thread
->ptid
) != pid
)
377 return thread
->private != NULL
;
381 have_threads (ptid_t ptid
)
383 int pid
= ptid_get_pid (ptid
);
385 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
388 struct thread_get_info_inout
390 struct thread_info
*thread_info
;
391 struct thread_db_info
*thread_db_info
;
394 /* A callback function for td_ta_thr_iter, which we use to map all
397 THP is a handle to the current thread; if INFOP is not NULL, the
398 struct thread_info associated with this thread is returned in
401 If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise,
402 zero is returned to indicate success. */
405 thread_get_info_callback (const td_thrhandle_t
*thp
, void *argp
)
410 struct thread_get_info_inout
*inout
;
411 struct thread_db_info
*info
;
414 info
= inout
->thread_db_info
;
416 err
= info
->td_thr_get_info_p (thp
, &ti
);
418 error (_("thread_get_info_callback: cannot get thread info: %s"),
419 thread_db_err_str (err
));
421 /* Fill the cache. */
422 thread_ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
423 inout
->thread_info
= find_thread_ptid (thread_ptid
);
425 /* In the case of a zombie thread, don't continue. We don't want to
426 attach to it thinking it is a new thread. */
427 if (ti
.ti_state
== TD_THR_UNKNOWN
|| ti
.ti_state
== TD_THR_ZOMBIE
)
428 return TD_THR_ZOMBIE
;
430 if (inout
->thread_info
== NULL
)
432 /* New thread. Attach to it now (why wait?). */
433 if (!have_threads (thread_ptid
))
434 thread_db_find_new_threads_1 (thread_ptid
);
436 attach_thread (thread_ptid
, thp
, &ti
);
437 inout
->thread_info
= find_thread_ptid (thread_ptid
);
438 gdb_assert (inout
->thread_info
!= NULL
);
444 /* Convert between user-level thread ids and LWP ids. */
447 thread_from_lwp (ptid_t ptid
)
451 struct thread_db_info
*info
;
452 struct thread_get_info_inout io
= {0};
454 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
457 /* This ptid comes from linux-nat.c, which should always fill in the
459 gdb_assert (GET_LWP (ptid
) != 0);
461 info
= get_thread_db_info (GET_PID (ptid
));
463 /* Access an lwp we know is stopped. */
464 info
->proc_handle
.ptid
= ptid
;
465 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, GET_LWP (ptid
), &th
);
467 error (_("Cannot find user-level thread for LWP %ld: %s"),
468 GET_LWP (ptid
), thread_db_err_str (err
));
470 /* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the
471 event thread has already died. If another gdb interface has called
472 thread_alive() previously, the thread won't be found on the thread list
473 anymore. In that case, we don't want to process this ptid anymore
474 to avoid the possibility of later treating it as a newly
475 discovered thread id that we should add to the list. Thus,
476 we return a -1 ptid which is also how the thread list marks a
478 io
.thread_db_info
= info
;
479 io
.thread_info
= NULL
;
480 if (thread_get_info_callback (&th
, &io
) == TD_THR_ZOMBIE
481 && io
.thread_info
== NULL
)
482 return minus_one_ptid
;
484 gdb_assert (ptid_get_tid (ptid
) == 0);
489 /* Attach to lwp PTID, doing whatever else is required to have this
490 LWP under the debugger's control --- e.g., enabling event
491 reporting. Returns true on success. */
493 thread_db_attach_lwp (ptid_t ptid
)
498 struct thread_db_info
*info
;
500 info
= get_thread_db_info (GET_PID (ptid
));
505 /* This ptid comes from linux-nat.c, which should always fill in the
507 gdb_assert (GET_LWP (ptid
) != 0);
509 /* Access an lwp we know is stopped. */
510 info
->proc_handle
.ptid
= ptid
;
512 /* If we have only looked at the first thread before libpthread was
513 initialized, we may not know its thread ID yet. Make sure we do
514 before we add another thread to the list. */
515 if (!have_threads (ptid
))
516 thread_db_find_new_threads_1 (ptid
);
518 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, GET_LWP (ptid
), &th
);
520 /* Cannot find user-level thread. */
523 err
= info
->td_thr_get_info_p (&th
, &ti
);
526 warning (_("Cannot get thread info: %s"), thread_db_err_str (err
));
530 attach_thread (ptid
, &th
, &ti
);
535 verbose_dlsym (void *handle
, const char *name
)
537 void *sym
= dlsym (handle
, name
);
539 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
545 enable_thread_event (int event
, CORE_ADDR
*bp
)
549 struct thread_db_info
*info
;
551 info
= get_thread_db_info (GET_PID (inferior_ptid
));
553 /* Access an lwp we know is stopped. */
554 info
->proc_handle
.ptid
= inferior_ptid
;
556 /* Get the breakpoint address for thread EVENT. */
557 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
561 /* Set up the breakpoint. */
562 gdb_assert (exec_bfd
);
563 (*bp
) = (gdbarch_convert_from_func_ptr_addr
565 /* Do proper sign extension for the target. */
566 (bfd_get_sign_extend_vma (exec_bfd
) > 0
567 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
568 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
570 create_thread_event_breakpoint (target_gdbarch
, *bp
);
575 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
576 return 1 if this version is lower (and not equal) to
577 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
580 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
582 struct minimal_symbol
*version_msym
;
583 CORE_ADDR version_addr
;
585 int err
, got
, retval
= 0;
587 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
588 if (version_msym
== NULL
)
591 version_addr
= SYMBOL_VALUE_ADDRESS (version_msym
);
592 got
= target_read_string (version_addr
, &version
, 32, &err
);
593 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
597 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
598 && (major
< ver_major_min
599 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
607 enable_thread_event_reporting (void)
609 td_thr_events_t events
;
611 struct thread_db_info
*info
;
613 info
= get_thread_db_info (GET_PID (inferior_ptid
));
615 /* We cannot use the thread event reporting facility if these
616 functions aren't available. */
617 if (info
->td_ta_event_addr_p
== NULL
618 || info
->td_ta_set_event_p
== NULL
619 || info
->td_ta_event_getmsg_p
== NULL
620 || info
->td_thr_event_enable_p
== NULL
)
623 /* Set the process wide mask saying which events we're interested in. */
624 td_event_emptyset (&events
);
625 td_event_addset (&events
, TD_CREATE
);
627 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
628 commit 2e4581e4fba917f1779cd0a010a45698586c190a
629 * manager.c (pthread_exited): Correctly report event as TD_REAP
630 instead of TD_DEATH. Fix comments.
631 where event reporting facility is broken for TD_DEATH events,
632 so don't enable it if we have glibc but a lower version. */
633 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
634 td_event_addset (&events
, TD_DEATH
);
636 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
639 warning (_("Unable to set global thread event mask: %s"),
640 thread_db_err_str (err
));
644 /* Delete previous thread event breakpoints, if any. */
645 remove_thread_event_breakpoints ();
646 info
->td_create_bp_addr
= 0;
647 info
->td_death_bp_addr
= 0;
649 /* Set up the thread creation event. */
650 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
653 warning (_("Unable to get location for thread creation breakpoint: %s"),
654 thread_db_err_str (err
));
658 /* Set up the thread death event. */
659 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
662 warning (_("Unable to get location for thread death breakpoint: %s"),
663 thread_db_err_str (err
));
668 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
671 Return 1 if the caller should abort libthread_db initialization. Return 0
675 thread_db_find_new_threads_silently (ptid_t ptid
)
677 volatile struct gdb_exception except
;
679 TRY_CATCH (except
, RETURN_MASK_ERROR
)
681 thread_db_find_new_threads_2 (ptid
, 1);
684 if (except
.reason
< 0)
686 if (libthread_db_debug
)
687 exception_fprintf (gdb_stderr
, except
,
688 "Warning: thread_db_find_new_threads_silently: ");
690 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
691 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
692 where calls to td_thr_get_info fail with TD_ERR for statically linked
693 executables if td_thr_get_info is called before glibc has initialized
696 If the nptl bug is NOT present in the inferior and still thread_db
697 reports an error return 1. It means the inferior has corrupted thread
698 list and GDB should fall back only to LWPs.
700 If the nptl bug is present in the inferior return 0 to silently ignore
701 such errors, and let gdb enumerate threads again later. In such case
702 GDB cannot properly display LWPs if the inferior thread list is
705 if (!inferior_has_bug ("nptl_version", 2, 7))
707 exception_fprintf (gdb_stderr
, except
,
708 _("Warning: couldn't activate thread debugging "
709 "using libthread_db: "));
716 /* Lookup a library in which given symbol resides.
717 Note: this is looking in GDB process, not in the inferior.
718 Returns library name, or NULL. */
721 dladdr_to_soname (const void *addr
)
725 if (dladdr (addr
, &info
) != 0)
726 return info
.dli_fname
;
730 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
732 Failure could happen if libthread_db does not have symbols we expect,
733 or when it refuses to work with the current inferior (e.g. due to
734 version mismatch between libthread_db and libpthread). */
737 try_thread_db_load_1 (struct thread_db_info
*info
)
741 /* Initialize pointers to the dynamic library functions we will use.
742 Essential functions first. */
744 info
->td_init_p
= verbose_dlsym (info
->handle
, "td_init");
745 if (info
->td_init_p
== NULL
)
748 err
= info
->td_init_p ();
751 warning (_("Cannot initialize libthread_db: %s"),
752 thread_db_err_str (err
));
756 info
->td_ta_new_p
= verbose_dlsym (info
->handle
, "td_ta_new");
757 if (info
->td_ta_new_p
== NULL
)
760 /* Initialize the structure that identifies the child process. */
761 info
->proc_handle
.ptid
= inferior_ptid
;
763 /* Now attempt to open a connection to the thread library. */
764 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
767 if (libthread_db_debug
)
768 printf_unfiltered (_("td_ta_new failed: %s\n"),
769 thread_db_err_str (err
));
774 #ifdef THREAD_DB_HAS_TD_VERSION
777 /* The errors above are not unexpected and silently ignored:
778 they just mean we haven't found correct version of
782 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
787 info
->td_ta_map_id2thr_p
= verbose_dlsym (info
->handle
, "td_ta_map_id2thr");
788 if (info
->td_ta_map_id2thr_p
== NULL
)
791 info
->td_ta_map_lwp2thr_p
= verbose_dlsym (info
->handle
,
792 "td_ta_map_lwp2thr");
793 if (info
->td_ta_map_lwp2thr_p
== NULL
)
796 info
->td_ta_thr_iter_p
= verbose_dlsym (info
->handle
, "td_ta_thr_iter");
797 if (info
->td_ta_thr_iter_p
== NULL
)
800 info
->td_thr_validate_p
= verbose_dlsym (info
->handle
, "td_thr_validate");
801 if (info
->td_thr_validate_p
== NULL
)
804 info
->td_thr_get_info_p
= verbose_dlsym (info
->handle
, "td_thr_get_info");
805 if (info
->td_thr_get_info_p
== NULL
)
808 /* These are not essential. */
809 info
->td_ta_event_addr_p
= dlsym (info
->handle
, "td_ta_event_addr");
810 info
->td_ta_set_event_p
= dlsym (info
->handle
, "td_ta_set_event");
811 info
->td_ta_clear_event_p
= dlsym (info
->handle
, "td_ta_clear_event");
812 info
->td_ta_event_getmsg_p
= dlsym (info
->handle
, "td_ta_event_getmsg");
813 info
->td_thr_event_enable_p
= dlsym (info
->handle
, "td_thr_event_enable");
814 info
->td_thr_tls_get_addr_p
= dlsym (info
->handle
, "td_thr_tls_get_addr");
816 if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
818 /* Even if libthread_db initializes, if the thread list is
819 corrupted, we'd not manage to list any threads. Better reject this
820 thread_db, and fall back to at least listing LWPs. */
824 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
826 if (libthread_db_debug
|| *libthread_db_search_path
)
830 library
= dladdr_to_soname (*info
->td_ta_new_p
);
832 library
= LIBTHREAD_DB_SO
;
834 printf_unfiltered (_("Using host libthread_db library \"%s\".\n"),
838 /* The thread library was detected. Activate the thread_db target
839 if this is the first process using it. */
840 if (thread_db_list
->next
== NULL
)
841 push_target (&thread_db_ops
);
843 /* Enable event reporting, but not when debugging a core file. */
844 if (target_has_execution
)
845 enable_thread_event_reporting ();
850 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
851 relative, or just LIBTHREAD_DB. */
854 try_thread_db_load (const char *library
)
857 struct thread_db_info
*info
;
859 if (libthread_db_debug
)
860 printf_unfiltered (_("Trying host libthread_db library: %s.\n"),
862 handle
= dlopen (library
, RTLD_NOW
);
865 if (libthread_db_debug
)
866 printf_unfiltered (_("dlopen failed: %s.\n"), dlerror ());
870 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
874 td_init
= dlsym (handle
, "td_init");
877 const char *const libpath
= dladdr_to_soname (td_init
);
880 printf_unfiltered (_("Host %s resolved to: %s.\n"),
885 info
= add_thread_db_info (handle
);
887 /* Do not save system library name, that one is always trusted. */
888 if (strchr (library
, '/') != NULL
)
889 info
->filename
= gdb_realpath (library
);
891 if (try_thread_db_load_1 (info
))
894 /* This library "refused" to work on current inferior. */
895 delete_thread_db_info (GET_PID (inferior_ptid
));
899 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
900 Try loading libthread_db from the same directory as OBJ.
901 The result is true for success. */
904 try_thread_db_load_from_pdir_1 (struct objfile
*obj
)
906 struct cleanup
*cleanup
;
910 if (obj
->name
[0] != '/')
912 warning (_("Expected absolute pathname for libpthread in the"
913 " inferior, but got %s."), obj
->name
);
917 path
= xmalloc (strlen (obj
->name
) + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
918 cleanup
= make_cleanup (xfree
, path
);
920 strcpy (path
, obj
->name
);
921 cp
= strrchr (path
, '/');
922 /* This should at minimum hit the first character. */
923 gdb_assert (cp
!= NULL
);
924 strcpy (cp
+ 1, LIBTHREAD_DB_SO
);
926 if (!file_is_auto_load_safe (path
, _("auto-load: Loading libthread-db "
927 "library \"%s\" from $pdir.\n"),
931 result
= try_thread_db_load (path
);
933 do_cleanups (cleanup
);
937 /* Handle $pdir in libthread-db-search-path.
938 Look for libthread_db in the directory of libpthread.
939 The result is true for success. */
942 try_thread_db_load_from_pdir (void)
946 if (!auto_load_thread_db
)
950 if (libpthread_name_p (obj
->name
))
952 if (try_thread_db_load_from_pdir_1 (obj
))
955 /* We may have found the separate-debug-info version of
956 libpthread, and it may live in a directory without a matching
958 if (obj
->separate_debug_objfile_backlink
!= NULL
)
959 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
);
967 /* Handle $sdir in libthread-db-search-path.
968 Look for libthread_db in the system dirs, or wherever a plain
969 dlopen(file_without_path) will look.
970 The result is true for success. */
973 try_thread_db_load_from_sdir (void)
975 return try_thread_db_load (LIBTHREAD_DB_SO
);
978 /* Try to load libthread_db from directory DIR of length DIR_LEN.
979 The result is true for success. */
982 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
984 struct cleanup
*cleanup
;
988 if (!auto_load_thread_db
)
991 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
992 cleanup
= make_cleanup (xfree
, path
);
994 memcpy (path
, dir
, dir_len
);
996 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
998 if (!file_is_auto_load_safe (path
, _("auto-load: Loading libthread-db "
999 "library \"%s\" from explicit "
1004 result
= try_thread_db_load (path
);
1006 do_cleanups (cleanup
);
1010 /* Search libthread_db_search_path for libthread_db which "agrees"
1011 to work on current inferior.
1012 The result is true for success. */
1015 thread_db_load_search (void)
1017 const char *search_path
= libthread_db_search_path
;
1020 while (*search_path
)
1022 const char *end
= strchr (search_path
, ':');
1023 const char *this_dir
= search_path
;
1024 size_t this_dir_len
;
1028 this_dir_len
= end
- search_path
;
1029 search_path
+= this_dir_len
+ 1;
1033 this_dir_len
= strlen (this_dir
);
1034 search_path
+= this_dir_len
;
1037 if (this_dir_len
== sizeof ("$pdir") - 1
1038 && strncmp (this_dir
, "$pdir", this_dir_len
) == 0)
1040 if (try_thread_db_load_from_pdir ())
1046 else if (this_dir_len
== sizeof ("$sdir") - 1
1047 && strncmp (this_dir
, "$sdir", this_dir_len
) == 0)
1049 if (try_thread_db_load_from_sdir ())
1057 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1065 if (libthread_db_debug
)
1066 printf_unfiltered (_("thread_db_load_search returning %d\n"), rc
);
1070 /* Return non-zero if the inferior has a libpthread. */
1073 has_libpthread (void)
1075 struct objfile
*obj
;
1078 if (libpthread_name_p (obj
->name
))
1084 /* Attempt to load and initialize libthread_db.
1085 Return 1 on success. */
1088 thread_db_load (void)
1090 struct thread_db_info
*info
;
1092 info
= get_thread_db_info (GET_PID (inferior_ptid
));
1097 /* Don't attempt to use thread_db on executables not running
1099 if (!target_has_registers
)
1102 /* Don't attempt to use thread_db for remote targets. */
1103 if (!(target_can_run (¤t_target
) || core_bfd
))
1106 if (thread_db_load_search ())
1109 /* We couldn't find a libthread_db.
1110 If the inferior has a libpthread warn the user. */
1111 if (has_libpthread ())
1113 warning (_("Unable to find libthread_db matching inferior's thread"
1114 " library, thread debugging will not be available."));
1118 /* Either this executable isn't using libpthread at all, or it is
1119 statically linked. Since we can't easily distinguish these two cases,
1120 no warning is issued. */
1125 disable_thread_event_reporting (struct thread_db_info
*info
)
1127 if (info
->td_ta_clear_event_p
!= NULL
)
1129 td_thr_events_t events
;
1131 /* Set the process wide mask saying we aren't interested in any
1133 td_event_fillset (&events
);
1134 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1137 info
->td_create_bp_addr
= 0;
1138 info
->td_death_bp_addr
= 0;
1142 check_thread_signals (void)
1144 if (!thread_signals
)
1149 lin_thread_get_thread_signals (&mask
);
1150 sigemptyset (&thread_stop_set
);
1151 sigemptyset (&thread_print_set
);
1153 for (i
= 1; i
< NSIG
; i
++)
1155 if (sigismember (&mask
, i
))
1157 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1158 sigaddset (&thread_stop_set
, i
);
1159 if (signal_print_update (gdb_signal_from_host (i
), 0))
1160 sigaddset (&thread_print_set
, i
);
1167 /* Check whether thread_db is usable. This function is called when
1168 an inferior is created (or otherwise acquired, e.g. attached to)
1169 and when new shared libraries are loaded into a running process. */
1172 check_for_thread_db (void)
1174 /* Do nothing if we couldn't load libthread_db.so.1. */
1175 if (!thread_db_load ())
1179 /* This function is called via the new_objfile observer. */
1182 thread_db_new_objfile (struct objfile
*objfile
)
1184 /* This observer must always be called with inferior_ptid set
1188 /* libpthread with separate debug info has its debug info file already
1189 loaded (and notified without successful thread_db initialization)
1190 the time observer_notify_new_objfile is called for the library itself.
1191 Static executables have their separate debug info loaded already
1192 before the inferior has started. */
1193 && objfile
->separate_debug_objfile_backlink
== NULL
1194 /* Only check for thread_db if we loaded libpthread,
1195 or if this is the main symbol file.
1196 We need to check OBJF_MAINLINE to handle the case of debugging
1197 a statically linked executable AND the symbol file is specified AFTER
1198 the exec file is loaded (e.g., gdb -c core ; file foo).
1199 For dynamically linked executables, libpthread can be near the end
1200 of the list of shared libraries to load, and in an app of several
1201 thousand shared libraries, this can otherwise be painful. */
1202 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1203 || libpthread_name_p (objfile
->name
)))
1204 check_for_thread_db ();
1207 /* This function is called via the inferior_created observer.
1208 This handles the case of debugging statically linked executables. */
1211 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1213 check_for_thread_db ();
1216 /* Attach to a new thread. This function is called when we receive a
1217 TD_CREATE event or when we iterate over all threads and find one
1218 that wasn't already in our list. Returns true on success. */
1221 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1222 const td_thrinfo_t
*ti_p
)
1224 struct private_thread_info
*private;
1225 struct thread_info
*tp
;
1227 struct thread_db_info
*info
;
1229 /* If we're being called after a TD_CREATE event, we may already
1230 know about this thread. There are two ways this can happen. We
1231 may have iterated over all threads between the thread creation
1232 and the TD_CREATE event, for instance when the user has issued
1233 the `info threads' command before the SIGTRAP for hitting the
1234 thread creation breakpoint was reported. Alternatively, the
1235 thread may have exited and a new one been created with the same
1236 thread ID. In the first case we don't need to do anything; in
1237 the second case we should discard information about the dead
1238 thread and attach to the new one. */
1239 tp
= find_thread_ptid (ptid
);
1242 /* If tp->private is NULL, then GDB is already attached to this
1243 thread, but we do not know anything about it. We can learn
1244 about it here. This can only happen if we have some other
1245 way besides libthread_db to notice new threads (i.e.
1246 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1247 exit, so this can not be a stale thread recreated with the
1249 if (tp
->private != NULL
)
1251 if (!tp
->private->dying
)
1254 delete_thread (ptid
);
1259 if (target_has_execution
)
1260 check_thread_signals ();
1262 if (ti_p
->ti_state
== TD_THR_UNKNOWN
|| ti_p
->ti_state
== TD_THR_ZOMBIE
)
1263 return 0; /* A zombie thread -- do not attach. */
1265 /* Under GNU/Linux, we have to attach to each and every thread. */
1266 if (target_has_execution
1271 res
= lin_lwp_attach_lwp (BUILD_LWP (ti_p
->ti_lid
, GET_PID (ptid
)));
1274 /* Error, stop iterating. */
1279 /* Pretend this thread doesn't exist yet, and keep
1284 /* Otherwise, we sucessfully attached to the thread. */
1287 /* Construct the thread's private data. */
1288 private = xmalloc (sizeof (struct private_thread_info
));
1289 memset (private, 0, sizeof (struct private_thread_info
));
1291 /* A thread ID of zero may mean the thread library has not initialized
1292 yet. But we shouldn't even get here if that's the case. FIXME:
1293 if we change GDB to always have at least one thread in the thread
1294 list this will have to go somewhere else; maybe private == NULL
1295 until the thread_db target claims it. */
1296 gdb_assert (ti_p
->ti_tid
!= 0);
1297 private->th
= *th_p
;
1298 private->tid
= ti_p
->ti_tid
;
1300 /* Add the thread to GDB's thread list. */
1302 add_thread_with_info (ptid
, private);
1304 tp
->private = private;
1306 info
= get_thread_db_info (GET_PID (ptid
));
1308 /* Enable thread event reporting for this thread, except when
1309 debugging a core file. */
1310 if (target_has_execution
)
1312 err
= info
->td_thr_event_enable_p (th_p
, 1);
1314 error (_("Cannot enable thread event reporting for %s: %s"),
1315 target_pid_to_str (ptid
), thread_db_err_str (err
));
1322 detach_thread (ptid_t ptid
)
1324 struct thread_info
*thread_info
;
1326 /* Don't delete the thread now, because it still reports as active
1327 until it has executed a few instructions after the event
1328 breakpoint - if we deleted it now, "info threads" would cause us
1329 to re-attach to it. Just mark it as having had a TD_DEATH
1330 event. This means that we won't delete it from our thread list
1331 until we notice that it's dead (via prune_threads), or until
1332 something re-uses its thread ID. We'll report the thread exit
1333 when the underlying LWP dies. */
1334 thread_info
= find_thread_ptid (ptid
);
1335 gdb_assert (thread_info
!= NULL
&& thread_info
->private != NULL
);
1336 thread_info
->private->dying
= 1;
1340 thread_db_detach (struct target_ops
*ops
, char *args
, int from_tty
)
1342 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1343 struct thread_db_info
*info
;
1345 info
= get_thread_db_info (GET_PID (inferior_ptid
));
1349 if (target_has_execution
)
1351 disable_thread_event_reporting (info
);
1353 /* Delete the old thread event breakpoints. Note that
1354 unlike when mourning, we can remove them here because
1355 there's still a live inferior to poke at. In any case,
1356 GDB will not try to insert anything in the inferior when
1357 removing a breakpoint. */
1358 remove_thread_event_breakpoints ();
1361 delete_thread_db_info (GET_PID (inferior_ptid
));
1364 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1366 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1368 /* If there are no more processes using libpthread, detach the
1369 thread_db target ops. */
1370 if (!thread_db_list
)
1371 unpush_target (&thread_db_ops
);
1374 /* Check if PID is currently stopped at the location of a thread event
1375 breakpoint location. If it is, read the event message and act upon
1379 check_event (ptid_t ptid
)
1381 struct regcache
*regcache
= get_thread_regcache (ptid
);
1382 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1388 struct thread_db_info
*info
;
1390 info
= get_thread_db_info (GET_PID (ptid
));
1392 /* Bail out early if we're not at a thread event breakpoint. */
1393 stop_pc
= regcache_read_pc (regcache
)
1394 - gdbarch_decr_pc_after_break (gdbarch
);
1395 if (stop_pc
!= info
->td_create_bp_addr
1396 && stop_pc
!= info
->td_death_bp_addr
)
1399 /* Access an lwp we know is stopped. */
1400 info
->proc_handle
.ptid
= ptid
;
1402 /* If we have only looked at the first thread before libpthread was
1403 initialized, we may not know its thread ID yet. Make sure we do
1404 before we add another thread to the list. */
1405 if (!have_threads (ptid
))
1406 thread_db_find_new_threads_1 (ptid
);
1408 /* If we are at a create breakpoint, we do not know what new lwp
1409 was created and cannot specifically locate the event message for it.
1410 We have to call td_ta_event_getmsg() to get
1411 the latest message. Since we have no way of correlating whether
1412 the event message we get back corresponds to our breakpoint, we must
1413 loop and read all event messages, processing them appropriately.
1414 This guarantees we will process the correct message before continuing
1415 from the breakpoint.
1417 Currently, death events are not enabled. If they are enabled,
1418 the death event can use the td_thr_event_getmsg() interface to
1419 get the message specifically for that lwp and avoid looping
1426 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1429 if (err
== TD_NOMSG
)
1432 error (_("Cannot get thread event message: %s"),
1433 thread_db_err_str (err
));
1436 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1438 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1440 ptid
= ptid_build (GET_PID (ptid
), ti
.ti_lid
, 0);
1445 /* Call attach_thread whether or not we already know about a
1446 thread with this thread ID. */
1447 attach_thread (ptid
, msg
.th_p
, &ti
);
1453 if (!in_thread_list (ptid
))
1454 error (_("Spurious thread death event."));
1456 detach_thread (ptid
);
1461 error (_("Spurious thread event."));
1468 thread_db_wait (struct target_ops
*ops
,
1469 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1472 struct thread_db_info
*info
;
1473 struct target_ops
*beneath
= find_target_beneath (ops
);
1475 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1477 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1480 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1481 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1484 info
= get_thread_db_info (GET_PID (ptid
));
1486 /* If this process isn't using thread_db, we're done. */
1490 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1492 /* New image, it may or may not end up using thread_db. Assume
1493 not unless we find otherwise. */
1494 delete_thread_db_info (GET_PID (ptid
));
1495 if (!thread_db_list
)
1496 unpush_target (&thread_db_ops
);
1498 /* Thread event breakpoints are deleted by
1499 update_breakpoints_after_exec. */
1504 /* If we do not know about the main thread yet, this would be a good time to
1506 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
&& !have_threads (ptid
))
1507 thread_db_find_new_threads_1 (ptid
);
1509 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1510 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1511 /* Check for a thread event. */
1514 if (have_threads (ptid
))
1516 /* Change ptids back into the higher level PID + TID format. If
1517 the thread is dead and no longer on the thread list, we will
1518 get back a dead ptid. This can occur if the thread death
1519 event gets postponed by other simultaneous events. In such a
1520 case, we want to just ignore the event and continue on. */
1522 ptid
= thread_from_lwp (ptid
);
1523 if (GET_PID (ptid
) == -1)
1524 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1531 thread_db_mourn_inferior (struct target_ops
*ops
)
1533 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1535 delete_thread_db_info (GET_PID (inferior_ptid
));
1537 target_beneath
->to_mourn_inferior (target_beneath
);
1539 /* Delete the old thread event breakpoints. Do this after mourning
1540 the inferior, so that we don't try to uninsert them. */
1541 remove_thread_event_breakpoints ();
1543 /* Detach thread_db target ops. */
1544 if (!thread_db_list
)
1545 unpush_target (ops
);
1548 struct callback_data
1550 struct thread_db_info
*info
;
1555 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1560 struct thread_info
*tp
;
1561 struct callback_data
*cb_data
= data
;
1562 struct thread_db_info
*info
= cb_data
->info
;
1564 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1566 error (_("find_new_threads_callback: cannot get thread info: %s"),
1567 thread_db_err_str (err
));
1569 if (ti
.ti_state
== TD_THR_UNKNOWN
|| ti
.ti_state
== TD_THR_ZOMBIE
)
1570 return 0; /* A zombie -- ignore. */
1574 /* A thread ID of zero means that this is the main thread, but
1575 glibc has not yet initialized thread-local storage and the
1576 pthread library. We do not know what the thread's TID will
1577 be yet. Just enable event reporting and otherwise ignore
1580 /* In that case, we're not stopped in a fork syscall and don't
1581 need this glibc bug workaround. */
1582 info
->need_stale_parent_threads_check
= 0;
1584 if (target_has_execution
)
1586 err
= info
->td_thr_event_enable_p (th_p
, 1);
1588 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1589 (int) ti
.ti_lid
, thread_db_err_str (err
));
1595 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1596 bit expensive, as it needs to open /proc/pid/status, so try to
1597 avoid doing the work if we know we don't have to. */
1598 if (info
->need_stale_parent_threads_check
)
1600 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1602 if (tgid
!= -1 && tgid
!= info
->pid
)
1606 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1607 tp
= find_thread_ptid (ptid
);
1608 if (tp
== NULL
|| tp
->private == NULL
)
1610 if (attach_thread (ptid
, th_p
, &ti
))
1611 cb_data
->new_threads
+= 1;
1613 /* Problem attaching this thread; perhaps it exited before we
1615 This could mean that the thread list inside glibc itself is in
1616 inconsistent state, and libthread_db could go on looping forever
1617 (observed with glibc-2.3.6). To prevent that, terminate
1618 iteration: thread_db_find_new_threads_2 will retry. */
1625 /* Helper for thread_db_find_new_threads_2.
1626 Returns number of new threads found. */
1629 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1632 volatile struct gdb_exception except
;
1633 struct callback_data data
;
1634 td_err_e err
= TD_ERR
;
1637 data
.new_threads
= 0;
1639 TRY_CATCH (except
, RETURN_MASK_ERROR
)
1641 /* Iterate over all user-space threads to discover new threads. */
1642 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1643 find_new_threads_callback
,
1646 TD_THR_LOWEST_PRIORITY
,
1648 TD_THR_ANY_USER_FLAGS
);
1651 if (libthread_db_debug
)
1653 if (except
.reason
< 0)
1654 exception_fprintf (gdb_stderr
, except
,
1655 "Warning: find_new_threads_once: ");
1657 printf_filtered (_("Found %d new threads in iteration %d.\n"),
1658 data
.new_threads
, iteration
);
1664 return data
.new_threads
;
1667 /* Search for new threads, accessing memory through stopped thread
1668 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1669 searches in a row do not discover any new threads. */
1672 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1674 td_err_e err
= TD_OK
;
1675 struct thread_db_info
*info
;
1676 int pid
= ptid_get_pid (ptid
);
1679 info
= get_thread_db_info (GET_PID (ptid
));
1681 /* Access an lwp we know is stopped. */
1682 info
->proc_handle
.ptid
= ptid
;
1686 /* Require 4 successive iterations which do not find any new threads.
1687 The 4 is a heuristic: there is an inherent race here, and I have
1688 seen that 2 iterations in a row are not always sufficient to
1689 "capture" all threads. */
1690 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1691 if (find_new_threads_once (info
, i
, &err
) != 0)
1693 /* Found some new threads. Restart the loop from beginning. */
1698 find_new_threads_once (info
, 0, &err
);
1701 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1705 thread_db_find_new_threads_1 (ptid_t ptid
)
1707 thread_db_find_new_threads_2 (ptid
, 0);
1711 update_thread_core (struct lwp_info
*info
, void *closure
)
1713 info
->core
= linux_common_core_of_thread (info
->ptid
);
1718 thread_db_find_new_threads (struct target_ops
*ops
)
1720 struct thread_db_info
*info
;
1721 struct inferior
*inf
;
1725 struct thread_info
*thread
;
1730 info
= get_thread_db_info (inf
->pid
);
1734 thread
= any_live_thread_of_process (inf
->pid
);
1735 if (thread
== NULL
|| thread
->executing
)
1738 thread_db_find_new_threads_1 (thread
->ptid
);
1741 if (target_has_execution
)
1742 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1743 update_thread_core
, NULL
);
1747 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1749 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1750 struct target_ops
*beneath
;
1752 if (thread_info
!= NULL
&& thread_info
->private != NULL
)
1754 static char buf
[64];
1757 tid
= thread_info
->private->tid
;
1758 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1759 tid
, GET_LWP (ptid
));
1764 beneath
= find_target_beneath (ops
);
1765 if (beneath
->to_pid_to_str (beneath
, ptid
))
1766 return beneath
->to_pid_to_str (beneath
, ptid
);
1768 return normal_pid_to_str (ptid
);
1771 /* Return a string describing the state of the thread specified by
1775 thread_db_extra_thread_info (struct thread_info
*info
)
1777 if (info
->private == NULL
)
1780 if (info
->private->dying
)
1786 /* Get the address of the thread local variable in load module LM which
1787 is stored at OFFSET within the thread local storage for thread PTID. */
1790 thread_db_get_thread_local_address (struct target_ops
*ops
,
1795 struct thread_info
*thread_info
;
1796 struct target_ops
*beneath
;
1798 /* If we have not discovered any threads yet, check now. */
1799 if (!have_threads (ptid
))
1800 thread_db_find_new_threads_1 (ptid
);
1802 /* Find the matching thread. */
1803 thread_info
= find_thread_ptid (ptid
);
1805 if (thread_info
!= NULL
&& thread_info
->private != NULL
)
1809 struct thread_db_info
*info
;
1811 info
= get_thread_db_info (GET_PID (ptid
));
1813 /* glibc doesn't provide the needed interface. */
1814 if (!info
->td_thr_tls_get_addr_p
)
1815 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1816 _("No TLS library support"));
1818 /* Caller should have verified that lm != 0. */
1819 gdb_assert (lm
!= 0);
1821 /* Finally, get the address of the variable. */
1822 /* Note the cast through uintptr_t: this interface only works if
1823 a target address fits in a psaddr_t, which is a host pointer.
1824 So a 32-bit debugger can not access 64-bit TLS through this. */
1825 err
= info
->td_thr_tls_get_addr_p (&thread_info
->private->th
,
1826 (psaddr_t
)(uintptr_t) lm
,
1829 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1830 /* The memory hasn't been allocated, yet. */
1831 if (err
== TD_NOTALLOC
)
1832 /* Now, if libthread_db provided the initialization image's
1833 address, we *could* try to build a non-lvalue value from
1834 the initialization image. */
1835 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1836 _("TLS not allocated yet"));
1839 /* Something else went wrong. */
1841 throw_error (TLS_GENERIC_ERROR
,
1842 (("%s")), thread_db_err_str (err
));
1844 /* Cast assuming host == target. Joy. */
1845 /* Do proper sign extension for the target. */
1846 gdb_assert (exec_bfd
);
1847 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1848 ? (CORE_ADDR
) (intptr_t) address
1849 : (CORE_ADDR
) (uintptr_t) address
);
1852 beneath
= find_target_beneath (ops
);
1853 if (beneath
->to_get_thread_local_address
)
1854 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1856 throw_error (TLS_GENERIC_ERROR
,
1857 _("TLS not supported on this target"));
1860 /* Callback routine used to find a thread based on the TID part of
1864 thread_db_find_thread_from_tid (struct thread_info
*thread
, void *data
)
1866 long *tid
= (long *) data
;
1868 if (thread
->private->tid
== *tid
)
1874 /* Implement the to_get_ada_task_ptid target method for this target. */
1877 thread_db_get_ada_task_ptid (long lwp
, long thread
)
1879 struct thread_info
*thread_info
;
1881 thread_db_find_new_threads_1 (inferior_ptid
);
1882 thread_info
= iterate_over_threads (thread_db_find_thread_from_tid
, &thread
);
1884 gdb_assert (thread_info
!= NULL
);
1886 return (thread_info
->ptid
);
1890 thread_db_resume (struct target_ops
*ops
,
1891 ptid_t ptid
, int step
, enum gdb_signal signo
)
1893 struct target_ops
*beneath
= find_target_beneath (ops
);
1894 struct thread_db_info
*info
;
1896 if (ptid_equal (ptid
, minus_one_ptid
))
1897 info
= get_thread_db_info (GET_PID (inferior_ptid
));
1899 info
= get_thread_db_info (GET_PID (ptid
));
1901 /* This workaround is only needed for child fork lwps stopped in a
1902 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1903 workaround can be disabled. */
1905 info
->need_stale_parent_threads_check
= 0;
1907 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1910 /* qsort helper function for info_auto_load_libthread_db, sort the
1911 thread_db_info pointers primarily by their FILENAME and secondarily by their
1912 PID, both in ascending order. */
1915 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1917 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1918 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1921 retval
= strcmp (a
->filename
, b
->filename
);
1925 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1928 /* Implement 'info auto-load libthread-db'. */
1931 info_auto_load_libthread_db (char *args
, int from_tty
)
1933 struct ui_out
*uiout
= current_uiout
;
1934 const char *cs
= args
? args
: "";
1935 struct thread_db_info
*info
, **array
;
1936 unsigned info_count
, unique_filenames
;
1937 size_t max_filename_len
, max_pids_len
, pids_len
;
1938 struct cleanup
*back_to
;
1942 while (isspace (*cs
))
1945 error (_("'info auto-load libthread-db' does not accept any parameters"));
1948 for (info
= thread_db_list
; info
; info
= info
->next
)
1949 if (info
->filename
!= NULL
)
1952 array
= xmalloc (sizeof (*array
) * info_count
);
1953 back_to
= make_cleanup (xfree
, array
);
1956 for (info
= thread_db_list
; info
; info
= info
->next
)
1957 if (info
->filename
!= NULL
)
1958 array
[info_count
++] = info
;
1960 /* Sort ARRAY by filenames and PIDs. */
1962 qsort (array
, info_count
, sizeof (*array
),
1963 info_auto_load_libthread_db_compare
);
1965 /* Calculate the number of unique filenames (rows) and the maximum string
1966 length of PIDs list for the unique filenames (columns). */
1968 unique_filenames
= 0;
1969 max_filename_len
= 0;
1972 for (i
= 0; i
< info_count
; i
++)
1974 int pid
= array
[i
]->pid
;
1975 size_t this_pid_len
;
1977 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
1980 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
1983 max_filename_len
= max (max_filename_len
,
1984 strlen (array
[i
]->filename
));
1988 pids_len
-= strlen (", ");
1989 max_pids_len
= max (max_pids_len
, pids_len
);
1993 pids_len
+= this_pid_len
+ strlen (", ");
1997 pids_len
-= strlen (", ");
1998 max_pids_len
= max (max_pids_len
, pids_len
);
2001 /* Table header shifted right by preceding "libthread-db: " would not match
2003 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2004 ui_out_text (uiout
, "\n");
2006 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2007 "LinuxThreadDbTable");
2009 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2011 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2012 ui_out_table_body (uiout
);
2014 pids
= xmalloc (max_pids_len
+ 1);
2015 make_cleanup (xfree
, pids
);
2017 /* Note I is incremented inside the cycle, not at its end. */
2018 for (i
= 0; i
< info_count
;)
2020 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2024 ui_out_field_string (uiout
, "filename", info
->filename
);
2027 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2029 if (pids_end
!= pids
)
2034 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2035 "%u", array
[i
]->pid
);
2036 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2042 ui_out_field_string (uiout
, "pids", pids
);
2044 ui_out_text (uiout
, "\n");
2045 do_cleanups (chain
);
2048 do_cleanups (back_to
);
2050 if (info_count
== 0)
2051 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2055 init_thread_db_ops (void)
2057 thread_db_ops
.to_shortname
= "multi-thread";
2058 thread_db_ops
.to_longname
= "multi-threaded child process.";
2059 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2060 thread_db_ops
.to_detach
= thread_db_detach
;
2061 thread_db_ops
.to_wait
= thread_db_wait
;
2062 thread_db_ops
.to_resume
= thread_db_resume
;
2063 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2064 thread_db_ops
.to_find_new_threads
= thread_db_find_new_threads
;
2065 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2066 thread_db_ops
.to_stratum
= thread_stratum
;
2067 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2068 thread_db_ops
.to_get_thread_local_address
2069 = thread_db_get_thread_local_address
;
2070 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2071 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2072 thread_db_ops
.to_magic
= OPS_MAGIC
;
2075 /* Provide a prototype to silence -Wmissing-prototypes. */
2076 extern initialize_file_ftype _initialize_thread_db
;
2079 _initialize_thread_db (void)
2081 init_thread_db_ops ();
2082 add_target (&thread_db_ops
);
2084 /* Defer loading of libthread_db.so until inferior is running.
2085 This allows gdb to load correct libthread_db for a given
2086 executable -- there could be mutiple versions of glibc,
2087 compiled with LinuxThreads or NPTL, and until there is
2088 a running inferior, we can't tell which libthread_db is
2089 the correct one to load. */
2091 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2093 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2095 &libthread_db_search_path
, _("\
2096 Set search path for libthread_db."), _("\
2097 Show the current search path or libthread_db."), _("\
2098 This path is used to search for libthread_db to be loaded into \
2100 Its value is a colon (':') separate list of directories to search.\n\
2101 Setting the search path to an empty list resets it to its default value."),
2102 set_libthread_db_search_path
,
2104 &setlist
, &showlist
);
2106 add_setshow_zinteger_cmd ("libthread-db", class_maintenance
,
2107 &libthread_db_debug
, _("\
2108 Set libthread-db debugging."), _("\
2109 Show libthread-db debugging."), _("\
2110 When non-zero, libthread-db debugging is enabled."),
2112 show_libthread_db_debug
,
2113 &setdebuglist
, &showdebuglist
);
2115 add_setshow_boolean_cmd ("libthread-db", class_support
,
2116 &auto_load_thread_db
, _("\
2117 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2118 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2119 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2120 locations to load libthread_db compatible with the inferior.\n\
2121 Standard system libthread_db still gets loaded even with this option off.\n\
2122 This options has security implications for untrusted inferiors."),
2123 NULL
, show_auto_load_thread_db
,
2124 auto_load_set_cmdlist_get (),
2125 auto_load_show_cmdlist_get ());
2127 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2128 _("Print the list of loaded inferior specific libthread_db.\n\
2129 Usage: info auto-load libthread-db"),
2130 auto_load_info_cmdlist_get ());
2132 /* Add ourselves to objfile event chain. */
2133 observer_attach_new_objfile (thread_db_new_objfile
);
2135 /* Add ourselves to inferior_created event chain.
2136 This is needed to handle debugging statically linked programs where
2137 the new_objfile observer won't get called for libpthread. */
2138 observer_attach_inferior_created (thread_db_inferior_created
);