1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2018 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"
38 #include "observable.h"
39 #include "linux-nat.h"
40 #include "nat/linux-procfs.h"
41 #include "nat/linux-ptrace.h"
42 #include "nat/linux-osdata.h"
43 #include "auto-load.h"
44 #include "cli/cli-utils.h"
47 #include "nat/linux-namespaces.h"
49 #include "common/pathstuff.h"
52 /* GNU/Linux libthread_db support.
54 libthread_db is a library, provided along with libpthread.so, which
55 exposes the internals of the thread library to a debugger. It
56 allows GDB to find existing threads, new threads as they are
57 created, thread IDs (usually, the result of pthread_self), and
58 thread-local variables.
60 The libthread_db interface originates on Solaris, where it is both
61 more powerful and more complicated. This implementation only works
62 for NPTL, the glibc threading library. It assumes that each thread
63 is permanently assigned to a single light-weight process (LWP). At
64 some point it also supported the older LinuxThreads library, but it
67 libthread_db-specific information is stored in the "private" field
68 of struct thread_info. When the field is NULL we do not yet have
69 information about the new thread; this could be temporary (created,
70 but the thread library's data structures do not reflect it yet)
71 or permanent (created using clone instead of pthread_create).
73 Process IDs managed by linux-thread-db.c match those used by
74 linux-nat.c: a common PID for all processes, an LWP ID for each
75 thread, and no TID. We save the TID in private. Keeping it out
76 of the ptid_t prevents thread IDs changing when libpthread is
77 loaded or unloaded. */
79 static const target_info thread_db_target_info = {
81 N_("multi-threaded child process."),
82 N_("Threads and pthreads support.")
85 class thread_db_target final : public target_ops
90 const target_info &info () const override
91 { return thread_db_target_info; }
93 void detach (inferior *, int) override;
94 ptid_t wait (ptid_t, struct target_waitstatus *, int) override;
95 void resume (ptid_t, int, enum gdb_signal) override;
96 void mourn_inferior () override;
97 void update_thread_list () override;
98 const char *pid_to_str (ptid_t) override;
99 CORE_ADDR get_thread_local_address (ptid_t ptid,
100 CORE_ADDR load_module_addr,
101 CORE_ADDR offset) override;
102 const char *extra_thread_info (struct thread_info *) override;
103 ptid_t get_ada_task_ptid (long lwp, long thread) override;
105 thread_info *thread_handle_to_thread_info (const gdb_byte *thread_handle,
107 inferior *inf) override;
110 thread_db_target::thread_db_target ()
112 this->to_stratum = thread_stratum;
115 static char *libthread_db_search_path;
117 /* Set to non-zero if thread_db auto-loading is enabled
118 by the "set auto-load libthread-db" command. */
119 static int auto_load_thread_db = 1;
121 /* Set to non-zero if load-time libthread_db tests have been enabled
122 by the "maintenence set check-libthread-db" command. */
123 static int check_thread_db_on_load = 0;
125 /* "show" command for the auto_load_thread_db configuration variable. */
128 show_auto_load_thread_db (struct ui_file *file, int from_tty,
129 struct cmd_list_element *c, const char *value)
131 fprintf_filtered (file, _("Auto-loading of inferior specific libthread_db "
137 set_libthread_db_search_path (const char *ignored, int from_tty,
138 struct cmd_list_element *c)
140 if (*libthread_db_search_path == '\0')
142 xfree (libthread_db_search_path);
143 libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
147 /* If non-zero, print details of libthread_db processing. */
149 static unsigned int libthread_db_debug;
152 show_libthread_db_debug (struct ui_file *file, int from_tty,
153 struct cmd_list_element *c, const char *value)
155 fprintf_filtered (file, _("libthread-db debugging is %s.\n"), value);
158 /* If we're running on GNU/Linux, we must explicitly attach to any new
161 /* This module's target vector. */
162 static thread_db_target the_thread_db_target;
164 /* Non-zero if we have determined the signals used by the threads
166 static int thread_signals;
167 static sigset_t thread_stop_set;
168 static sigset_t thread_print_set;
170 struct thread_db_info
172 struct thread_db_info *next;
174 /* Process id this object refers to. */
177 /* Handle from dlopen for libthread_db.so. */
180 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
181 HANDLE. It may be NULL for system library. */
184 /* Structure that identifies the child process for the
185 <proc_service.h> interface. */
186 struct ps_prochandle proc_handle;
188 /* Connection to the libthread_db library. */
189 td_thragent_t *thread_agent;
191 /* True if we need to apply the workaround for glibc/BZ5983. When
192 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
193 list, nptl_db returns the parent's threads in addition to the new
194 (single) child thread. If this flag is set, we do extra work to
195 be able to ignore such stale entries. */
196 int need_stale_parent_threads_check;
198 /* Pointers to the libthread_db functions. */
200 td_init_ftype *td_init_p;
201 td_ta_new_ftype *td_ta_new_p;
202 td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p;
203 td_ta_thr_iter_ftype *td_ta_thr_iter_p;
204 td_thr_get_info_ftype *td_thr_get_info_p;
205 td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p;
206 td_thr_tlsbase_ftype *td_thr_tlsbase_p;
209 /* List of known processes using thread_db, and the required
211 struct thread_db_info *thread_db_list;
213 static void thread_db_find_new_threads_1 (ptid_t ptid);
214 static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new);
216 static void check_thread_signals (void);
218 static struct thread_info *record_thread
219 (struct thread_db_info *info, struct thread_info *tp,
220 ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p);
222 /* Add the current inferior to the list of processes using libpthread.
223 Return a pointer to the newly allocated object that was added to
224 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
227 static struct thread_db_info *
228 add_thread_db_info (void *handle)
230 struct thread_db_info *info = XCNEW (struct thread_db_info);
232 info->pid = ptid_get_pid (inferior_ptid);
233 info->handle = handle;
235 /* The workaround works by reading from /proc/pid/status, so it is
236 disabled for core files. */
237 if (target_has_execution)
238 info->need_stale_parent_threads_check = 1;
240 info->next = thread_db_list;
241 thread_db_list = info;
246 /* Return the thread_db_info object representing the bookkeeping
247 related to process PID, if any; NULL otherwise. */
249 static struct thread_db_info *
250 get_thread_db_info (int pid)
252 struct thread_db_info *info;
254 for (info = thread_db_list; info; info = info->next)
255 if (pid == info->pid)
261 /* When PID has exited or has been detached, we no longer want to keep
262 track of it as using libpthread. Call this function to discard
263 thread_db related info related to PID. Note that this closes
264 LIBTHREAD_DB_SO's dlopen'ed handle. */
267 delete_thread_db_info (int pid)
269 struct thread_db_info *info, *info_prev;
273 for (info = thread_db_list; info; info_prev = info, info = info->next)
274 if (pid == info->pid)
280 if (info->handle != NULL)
281 dlclose (info->handle);
283 xfree (info->filename);
286 info_prev->next = info->next;
288 thread_db_list = info->next;
293 /* Use "struct private_thread_info" to cache thread state. This is
294 a substantial optimization. */
296 struct thread_db_thread_info : public private_thread_info
298 /* Flag set when we see a TD_DEATH event for this thread. */
301 /* Cached thread state. */
302 td_thrhandle_t th {};
306 static thread_db_thread_info *
307 get_thread_db_thread_info (thread_info *thread)
309 return static_cast<thread_db_thread_info *> (thread->priv.get ());
313 thread_db_err_str (td_err_e err)
320 return "generic 'call succeeded'";
322 return "generic error";
324 return "no thread to satisfy query";
326 return "no sync handle to satisfy query";
328 return "no LWP to satisfy query";
330 return "invalid process handle";
332 return "invalid thread handle";
334 return "invalid synchronization handle";
336 return "invalid thread agent";
338 return "invalid key";
340 return "no event message for getmsg";
342 return "FPU register set not available";
344 return "application not linked with libthread";
346 return "requested event is not supported";
348 return "capability not available";
350 return "debugger service failed";
352 return "operation not applicable to";
354 return "no thread-specific data for this thread";
356 return "malloc failed";
358 return "only part of register set was written/read";
360 return "X register set not available for this thread";
361 #ifdef THREAD_DB_HAS_TD_NOTALLOC
363 return "thread has not yet allocated TLS for given module";
365 #ifdef THREAD_DB_HAS_TD_VERSION
367 return "versions of libpthread and libthread_db do not match";
369 #ifdef THREAD_DB_HAS_TD_NOTLS
371 return "there is no TLS segment in the given module";
374 snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
379 /* Fetch the user-level thread id of PTID. */
381 static struct thread_info *
382 thread_from_lwp (ptid_t ptid)
387 struct thread_db_info *info;
388 struct thread_info *tp;
390 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
393 /* This ptid comes from linux-nat.c, which should always fill in the
395 gdb_assert (ptid_get_lwp (ptid) != 0);
397 info = get_thread_db_info (ptid_get_pid (ptid));
399 /* Access an lwp we know is stopped. */
400 info->proc_handle.ptid = ptid;
401 err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid_get_lwp (ptid),
404 error (_("Cannot find user-level thread for LWP %ld: %s"),
405 ptid_get_lwp (ptid), thread_db_err_str (err));
407 err = info->td_thr_get_info_p (&th, &ti);
409 error (_("thread_get_info_callback: cannot get thread info: %s"),
410 thread_db_err_str (err));
412 /* Fill the cache. */
413 tp = find_thread_ptid (ptid);
414 return record_thread (info, tp, ptid, &th, &ti);
418 /* See linux-nat.h. */
421 thread_db_notice_clone (ptid_t parent, ptid_t child)
423 struct thread_db_info *info;
425 info = get_thread_db_info (ptid_get_pid (child));
430 thread_from_lwp (child);
432 /* If we do not know about the main thread yet, this would be a good
434 thread_from_lwp (parent);
439 verbose_dlsym (void *handle, const char *name)
441 void *sym = dlsym (handle, name);
443 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
448 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
449 return 1 if this version is lower (and not equal) to
450 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
453 inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min)
455 struct bound_minimal_symbol version_msym;
456 CORE_ADDR version_addr;
457 gdb::unique_xmalloc_ptr<char> version;
458 int err, got, retval = 0;
460 version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL);
461 if (version_msym.minsym == NULL)
464 version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym);
465 got = target_read_string (version_addr, &version, 32, &err);
466 if (err == 0 && memchr (version.get (), 0, got) == version.get () + got - 1)
470 retval = (sscanf (version.get (), "%d.%d", &major, &minor) == 2
471 && (major < ver_major_min
472 || (major == ver_major_min && minor < ver_minor_min)));
478 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
481 Return 1 if the caller should abort libthread_db initialization. Return 0
485 thread_db_find_new_threads_silently (ptid_t ptid)
490 thread_db_find_new_threads_2 (ptid, 1);
493 CATCH (except, RETURN_MASK_ERROR)
495 if (libthread_db_debug)
496 exception_fprintf (gdb_stdlog, except,
497 "Warning: thread_db_find_new_threads_silently: ");
499 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
500 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
501 where calls to td_thr_get_info fail with TD_ERR for statically linked
502 executables if td_thr_get_info is called before glibc has initialized
505 If the nptl bug is NOT present in the inferior and still thread_db
506 reports an error return 1. It means the inferior has corrupted thread
507 list and GDB should fall back only to LWPs.
509 If the nptl bug is present in the inferior return 0 to silently ignore
510 such errors, and let gdb enumerate threads again later. In such case
511 GDB cannot properly display LWPs if the inferior thread list is
512 corrupted. For core files it does not apply, no 'later enumeration'
515 if (!target_has_execution || !inferior_has_bug ("nptl_version", 2, 7))
517 exception_fprintf (gdb_stderr, except,
518 _("Warning: couldn't activate thread debugging "
519 "using libthread_db: "));
528 /* Lookup a library in which given symbol resides.
529 Note: this is looking in GDB process, not in the inferior.
530 Returns library name, or NULL. */
533 dladdr_to_soname (const void *addr)
537 if (dladdr (addr, &info) != 0)
538 return info.dli_fname;
542 /* State for check_thread_db_callback. */
544 struct check_thread_db_info
546 /* The libthread_db under test. */
547 struct thread_db_info *info;
549 /* True if progress should be logged. */
552 /* True if the callback was called. */
555 /* Name of last libthread_db function called. */
556 const char *last_call;
558 /* Value returned by last libthread_db call. */
559 td_err_e last_result;
562 static struct check_thread_db_info *tdb_testinfo;
564 /* Callback for check_thread_db. */
567 check_thread_db_callback (const td_thrhandle_t *th, void *arg)
569 gdb_assert (tdb_testinfo != NULL);
570 tdb_testinfo->threads_seen = true;
572 #define LOG(fmt, args...) \
575 if (tdb_testinfo->log_progress) \
577 debug_printf (fmt, ## args); \
578 gdb_flush (gdb_stdlog); \
583 #define CHECK_1(expr, args...) \
588 LOG (" ... FAIL!\n"); \
594 #define CHECK(expr) \
595 CHECK_1 (expr, "(%s) == false", #expr)
597 #define CALL_UNCHECKED(func, args...) \
600 tdb_testinfo->last_call = #func; \
601 tdb_testinfo->last_result \
602 = tdb_testinfo->info->func ## _p (args); \
606 #define CHECK_CALL() \
607 CHECK_1 (tdb_testinfo->last_result == TD_OK, \
608 _("%s failed: %s"), \
609 tdb_testinfo->last_call, \
610 thread_db_err_str (tdb_testinfo->last_result)) \
612 #define CALL(func, args...) \
615 CALL_UNCHECKED (func, args); \
622 /* Check td_ta_thr_iter passed consistent arguments. */
624 CHECK (arg == (void *) tdb_testinfo);
625 CHECK (th->th_ta_p == tdb_testinfo->info->thread_agent);
627 LOG (" %s", core_addr_to_string_nz ((CORE_ADDR) th->th_unique));
629 /* Check td_thr_get_info. */
631 CALL (td_thr_get_info, th, &ti);
633 LOG (" => %d", ti.ti_lid);
635 CHECK (ti.ti_ta_p == th->th_ta_p);
636 CHECK (ti.ti_tid == (thread_t) th->th_unique);
638 /* Check td_ta_map_lwp2thr. */
640 memset (&th2, 23, sizeof (td_thrhandle_t));
641 CALL_UNCHECKED (td_ta_map_lwp2thr, th->th_ta_p, ti.ti_lid, &th2);
643 if (tdb_testinfo->last_result == TD_ERR && !target_has_execution)
645 /* Some platforms require execution for td_ta_map_lwp2thr. */
646 LOG (_("; can't map_lwp2thr"));
652 LOG (" => %s", core_addr_to_string_nz ((CORE_ADDR) th2.th_unique));
654 CHECK (memcmp (th, &th2, sizeof (td_thrhandle_t)) == 0);
657 /* Attempt TLS access. Assuming errno is TLS, this calls
658 thread_db_get_thread_local_address, which in turn calls
659 td_thr_tls_get_addr for live inferiors or td_thr_tlsbase
660 for core files. This test is skipped if the thread has
661 not been recorded; proceeding in that case would result
662 in the test having the side-effect of noticing threads
665 Note that in glibc's libthread_db td_thr_tls_get_addr is
666 a thin wrapper around td_thr_tlsbase; this check always
667 hits the bulk of the code.
669 Note also that we don't actually check any libthread_db
670 calls are made, we just assume they were; future changes
671 to how GDB accesses TLS could result in this passing
672 without exercising the calls it's supposed to. */
673 ptid_t ptid = ptid_build (tdb_testinfo->info->pid, ti.ti_lid, 0);
674 struct thread_info *thread_info = find_thread_ptid (ptid);
675 if (thread_info != NULL && thread_info->priv != NULL)
679 scoped_restore_current_thread restore_current_thread;
680 switch_to_thread (ptid);
682 expression_up expr = parse_expression ("(int) errno");
683 struct value *val = evaluate_expression (expr.get ());
685 if (tdb_testinfo->log_progress)
687 struct value_print_options opts;
689 get_user_print_options (&opts);
691 value_print (val, gdb_stdlog, &opts);
700 #undef CALL_UNCHECKED
707 /* Run integrity checks on the dlopen()ed libthread_db described by
708 INFO. Returns true on success, displays a warning and returns
709 false on failure. Logs progress messages to gdb_stdlog during
710 the test if LOG_PROGRESS is true. */
713 check_thread_db (struct thread_db_info *info, bool log_progress)
715 bool test_passed = true;
718 debug_printf (_("Running libthread_db integrity checks:\n"));
720 /* GDB avoids using td_ta_thr_iter wherever possible (see comment
721 in try_thread_db_load_1 below) so in order to test it we may
722 have to locate it ourselves. */
723 td_ta_thr_iter_ftype *td_ta_thr_iter_p = info->td_ta_thr_iter_p;
724 if (td_ta_thr_iter_p == NULL)
726 void *thr_iter = verbose_dlsym (info->handle, "td_ta_thr_iter");
727 if (thr_iter == NULL)
730 td_ta_thr_iter_p = (td_ta_thr_iter_ftype *) thr_iter;
733 /* Set up the test state we share with the callback. */
734 gdb_assert (tdb_testinfo == NULL);
735 struct check_thread_db_info tdb_testinfo_buf;
736 tdb_testinfo = &tdb_testinfo_buf;
738 memset (tdb_testinfo, 0, sizeof (struct check_thread_db_info));
739 tdb_testinfo->info = info;
740 tdb_testinfo->log_progress = log_progress;
742 /* td_ta_thr_iter shouldn't be used on running processes. Note that
743 it's possible the inferior will stop midway through modifying one
744 of its thread lists, in which case the check will spuriously
746 linux_stop_and_wait_all_lwps ();
750 td_err_e err = td_ta_thr_iter_p (info->thread_agent,
751 check_thread_db_callback,
754 TD_THR_LOWEST_PRIORITY,
756 TD_THR_ANY_USER_FLAGS);
759 error (_("td_ta_thr_iter failed: %s"), thread_db_err_str (err));
761 if (!tdb_testinfo->threads_seen)
762 error (_("no threads seen"));
764 CATCH (except, RETURN_MASK_ERROR)
766 if (warning_pre_print)
767 fputs_unfiltered (warning_pre_print, gdb_stderr);
769 exception_fprintf (gdb_stderr, except,
770 _("libthread_db integrity checks failed: "));
776 if (test_passed && log_progress)
777 debug_printf (_("libthread_db integrity checks passed.\n"));
781 linux_unstop_all_lwps ();
786 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
788 Failure could happen if libthread_db does not have symbols we expect,
789 or when it refuses to work with the current inferior (e.g. due to
790 version mismatch between libthread_db and libpthread). */
793 try_thread_db_load_1 (struct thread_db_info *info)
797 /* Initialize pointers to the dynamic library functions we will use.
798 Essential functions first. */
800 #define TDB_VERBOSE_DLSYM(info, func) \
801 info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
803 #define TDB_DLSYM(info, func) \
804 info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
813 CHK (TDB_VERBOSE_DLSYM (info, td_init));
815 err = info->td_init_p ();
818 warning (_("Cannot initialize libthread_db: %s"),
819 thread_db_err_str (err));
823 CHK (TDB_VERBOSE_DLSYM (info, td_ta_new));
825 /* Initialize the structure that identifies the child process. */
826 info->proc_handle.ptid = inferior_ptid;
828 /* Now attempt to open a connection to the thread library. */
829 err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
832 if (libthread_db_debug)
833 fprintf_unfiltered (gdb_stdlog, _("td_ta_new failed: %s\n"),
834 thread_db_err_str (err));
839 #ifdef THREAD_DB_HAS_TD_VERSION
842 /* The errors above are not unexpected and silently ignored:
843 they just mean we haven't found correct version of
847 warning (_("td_ta_new failed: %s"), thread_db_err_str (err));
852 /* These are essential. */
853 CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr));
854 CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info));
856 /* These are not essential. */
857 TDB_DLSYM (info, td_thr_tls_get_addr);
858 TDB_DLSYM (info, td_thr_tlsbase);
860 /* It's best to avoid td_ta_thr_iter if possible. That walks data
861 structures in the inferior's address space that may be corrupted,
862 or, if the target is running, may change while we walk them. If
863 there's execution (and /proc is mounted), then we're already
864 attached to all LWPs. Use thread_from_lwp, which uses
865 td_ta_map_lwp2thr instead, which does not walk the thread list.
867 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
868 currently on core targets, as it uses ptrace directly. */
869 if (target_has_execution
870 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid)))
871 info->td_ta_thr_iter_p = NULL;
873 CHK (TDB_VERBOSE_DLSYM (info, td_ta_thr_iter));
875 #undef TDB_VERBOSE_DLSYM
879 /* Run integrity checks if requested. */
880 if (check_thread_db_on_load)
882 if (!check_thread_db (info, libthread_db_debug))
886 if (info->td_ta_thr_iter_p == NULL)
889 int pid = ptid_get_pid (inferior_ptid);
891 linux_stop_and_wait_all_lwps ();
894 if (ptid_get_pid (lp->ptid) == pid)
895 thread_from_lwp (lp->ptid);
897 linux_unstop_all_lwps ();
899 else if (thread_db_find_new_threads_silently (inferior_ptid) != 0)
901 /* Even if libthread_db initializes, if the thread list is
902 corrupted, we'd not manage to list any threads. Better reject this
903 thread_db, and fall back to at least listing LWPs. */
907 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
909 if (*libthread_db_search_path || libthread_db_debug)
911 struct ui_file *file;
914 library = dladdr_to_soname ((const void *) *info->td_ta_new_p);
916 library = LIBTHREAD_DB_SO;
918 /* If we'd print this to gdb_stdout when debug output is
919 disabled, still print it to gdb_stdout if debug output is
920 enabled. User visible output should not depend on debug
922 file = *libthread_db_search_path != '\0' ? gdb_stdout : gdb_stdlog;
923 fprintf_unfiltered (file, _("Using host libthread_db library \"%s\".\n"),
927 /* The thread library was detected. Activate the thread_db target
928 if this is the first process using it. */
929 if (thread_db_list->next == NULL)
930 push_target (&the_thread_db_target);
935 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
936 relative, or just LIBTHREAD_DB. */
939 try_thread_db_load (const char *library, int check_auto_load_safe)
942 struct thread_db_info *info;
944 if (libthread_db_debug)
945 fprintf_unfiltered (gdb_stdlog,
946 _("Trying host libthread_db library: %s.\n"),
949 if (check_auto_load_safe)
951 if (access (library, R_OK) != 0)
953 /* Do not print warnings by file_is_auto_load_safe if the library does
954 not exist at this place. */
955 if (libthread_db_debug)
956 fprintf_unfiltered (gdb_stdlog, _("open failed: %s.\n"),
957 safe_strerror (errno));
961 if (!file_is_auto_load_safe (library, _("auto-load: Loading libthread-db "
962 "library \"%s\" from explicit "
968 handle = dlopen (library, RTLD_NOW);
971 if (libthread_db_debug)
972 fprintf_unfiltered (gdb_stdlog, _("dlopen failed: %s.\n"), dlerror ());
976 if (libthread_db_debug && strchr (library, '/') == NULL)
980 td_init = dlsym (handle, "td_init");
983 const char *const libpath = dladdr_to_soname (td_init);
986 fprintf_unfiltered (gdb_stdlog, _("Host %s resolved to: %s.\n"),
991 info = add_thread_db_info (handle);
993 /* Do not save system library name, that one is always trusted. */
994 if (strchr (library, '/') != NULL)
995 info->filename = gdb_realpath (library).release ();
997 if (try_thread_db_load_1 (info))
1000 /* This library "refused" to work on current inferior. */
1001 delete_thread_db_info (ptid_get_pid (inferior_ptid));
1005 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
1006 Try loading libthread_db in directory(OBJ)/SUBDIR.
1007 SUBDIR may be NULL. It may also be something like "../lib64".
1008 The result is true for success. */
1011 try_thread_db_load_from_pdir_1 (struct objfile *obj, const char *subdir)
1013 const char *obj_name = objfile_name (obj);
1015 if (obj_name[0] != '/')
1017 warning (_("Expected absolute pathname for libpthread in the"
1018 " inferior, but got %s."), obj_name);
1022 std::string path = obj_name;
1023 size_t cp = path.rfind ('/');
1024 /* This should at minimum hit the first character. */
1025 gdb_assert (cp != std::string::npos);
1026 path.resize (cp + 1);
1028 path = path + subdir + "/";
1029 path += LIBTHREAD_DB_SO;
1031 return try_thread_db_load (path.c_str (), 1);
1034 /* Handle $pdir in libthread-db-search-path.
1035 Look for libthread_db in directory(libpthread)/SUBDIR.
1036 SUBDIR may be NULL. It may also be something like "../lib64".
1037 The result is true for success. */
1040 try_thread_db_load_from_pdir (const char *subdir)
1042 struct objfile *obj;
1044 if (!auto_load_thread_db)
1048 if (libpthread_name_p (objfile_name (obj)))
1050 if (try_thread_db_load_from_pdir_1 (obj, subdir))
1053 /* We may have found the separate-debug-info version of
1054 libpthread, and it may live in a directory without a matching
1056 if (obj->separate_debug_objfile_backlink != NULL)
1057 return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink,
1066 /* Handle $sdir in libthread-db-search-path.
1067 Look for libthread_db in the system dirs, or wherever a plain
1068 dlopen(file_without_path) will look.
1069 The result is true for success. */
1072 try_thread_db_load_from_sdir (void)
1074 return try_thread_db_load (LIBTHREAD_DB_SO, 0);
1077 /* Try to load libthread_db from directory DIR of length DIR_LEN.
1078 The result is true for success. */
1081 try_thread_db_load_from_dir (const char *dir, size_t dir_len)
1083 if (!auto_load_thread_db)
1086 std::string path = std::string (dir, dir_len) + "/" + LIBTHREAD_DB_SO;
1088 return try_thread_db_load (path.c_str (), 1);
1091 /* Search libthread_db_search_path for libthread_db which "agrees"
1092 to work on current inferior.
1093 The result is true for success. */
1096 thread_db_load_search (void)
1100 std::vector<gdb::unique_xmalloc_ptr<char>> dir_vec
1101 = dirnames_to_char_ptr_vec (libthread_db_search_path);
1103 for (const gdb::unique_xmalloc_ptr<char> &this_dir_up : dir_vec)
1105 const char *this_dir = this_dir_up.get ();
1106 const int pdir_len = sizeof ("$pdir") - 1;
1107 size_t this_dir_len;
1109 this_dir_len = strlen (this_dir);
1111 if (strncmp (this_dir, "$pdir", pdir_len) == 0
1112 && (this_dir[pdir_len] == '\0'
1113 || this_dir[pdir_len] == '/'))
1115 const char *subdir = NULL;
1117 std::string subdir_holder;
1118 if (this_dir[pdir_len] == '/')
1120 subdir_holder = std::string (this_dir + pdir_len + 1);
1121 subdir = subdir_holder.c_str ();
1123 rc = try_thread_db_load_from_pdir (subdir);
1127 else if (strcmp (this_dir, "$sdir") == 0)
1129 if (try_thread_db_load_from_sdir ())
1137 if (try_thread_db_load_from_dir (this_dir, this_dir_len))
1145 if (libthread_db_debug)
1146 fprintf_unfiltered (gdb_stdlog,
1147 _("thread_db_load_search returning %d\n"), rc);
1151 /* Return non-zero if the inferior has a libpthread. */
1154 has_libpthread (void)
1156 struct objfile *obj;
1159 if (libpthread_name_p (objfile_name (obj)))
1165 /* Attempt to load and initialize libthread_db.
1166 Return 1 on success. */
1169 thread_db_load (void)
1171 struct thread_db_info *info;
1173 info = get_thread_db_info (ptid_get_pid (inferior_ptid));
1178 /* Don't attempt to use thread_db on executables not running
1180 if (!target_has_registers)
1183 /* Don't attempt to use thread_db for remote targets. */
1184 if (!(target_can_run () || core_bfd))
1187 if (thread_db_load_search ())
1190 /* We couldn't find a libthread_db.
1191 If the inferior has a libpthread warn the user. */
1192 if (has_libpthread ())
1194 warning (_("Unable to find libthread_db matching inferior's thread"
1195 " library, thread debugging will not be available."));
1199 /* Either this executable isn't using libpthread at all, or it is
1200 statically linked. Since we can't easily distinguish these two cases,
1201 no warning is issued. */
1206 check_thread_signals (void)
1208 if (!thread_signals)
1213 lin_thread_get_thread_signals (&mask);
1214 sigemptyset (&thread_stop_set);
1215 sigemptyset (&thread_print_set);
1217 for (i = 1; i < NSIG; i++)
1219 if (sigismember (&mask, i))
1221 if (signal_stop_update (gdb_signal_from_host (i), 0))
1222 sigaddset (&thread_stop_set, i);
1223 if (signal_print_update (gdb_signal_from_host (i), 0))
1224 sigaddset (&thread_print_set, i);
1231 /* Check whether thread_db is usable. This function is called when
1232 an inferior is created (or otherwise acquired, e.g. attached to)
1233 and when new shared libraries are loaded into a running process. */
1236 check_for_thread_db (void)
1238 /* Do nothing if we couldn't load libthread_db.so.1. */
1239 if (!thread_db_load ())
1243 /* This function is called via the new_objfile observer. */
1246 thread_db_new_objfile (struct objfile *objfile)
1248 /* This observer must always be called with inferior_ptid set
1252 /* libpthread with separate debug info has its debug info file already
1253 loaded (and notified without successful thread_db initialization)
1254 the time gdb::observers::new_objfile.notify is called for the library itself.
1255 Static executables have their separate debug info loaded already
1256 before the inferior has started. */
1257 && objfile->separate_debug_objfile_backlink == NULL
1258 /* Only check for thread_db if we loaded libpthread,
1259 or if this is the main symbol file.
1260 We need to check OBJF_MAINLINE to handle the case of debugging
1261 a statically linked executable AND the symbol file is specified AFTER
1262 the exec file is loaded (e.g., gdb -c core ; file foo).
1263 For dynamically linked executables, libpthread can be near the end
1264 of the list of shared libraries to load, and in an app of several
1265 thousand shared libraries, this can otherwise be painful. */
1266 && ((objfile->flags & OBJF_MAINLINE) != 0
1267 || libpthread_name_p (objfile_name (objfile))))
1268 check_for_thread_db ();
1272 check_pid_namespace_match (void)
1274 /* Check is only relevant for local targets targets. */
1275 if (target_can_run ())
1277 /* If the child is in a different PID namespace, its idea of its
1278 PID will differ from our idea of its PID. When we scan the
1279 child's thread list, we'll mistakenly think it has no threads
1280 since the thread PID fields won't match the PID we give to
1282 if (!linux_ns_same (ptid_get_pid (inferior_ptid), LINUX_NS_PID))
1284 warning (_ ("Target and debugger are in different PID "
1285 "namespaces; thread lists and other data are "
1286 "likely unreliable. "
1287 "Connect to gdbserver inside the container."));
1292 /* This function is called via the inferior_created observer.
1293 This handles the case of debugging statically linked executables. */
1296 thread_db_inferior_created (struct target_ops *target, int from_tty)
1298 check_pid_namespace_match ();
1299 check_for_thread_db ();
1302 /* Update the thread's state (what's displayed in "info threads"),
1303 from libthread_db thread state information. */
1306 update_thread_state (thread_db_thread_info *priv,
1307 const td_thrinfo_t *ti_p)
1309 priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN
1310 || ti_p->ti_state == TD_THR_ZOMBIE);
1313 /* Record a new thread in GDB's thread list. Creates the thread's
1314 private info. If TP is NULL or TP is marked as having exited,
1315 creates a new thread. Otherwise, uses TP. */
1317 static struct thread_info *
1318 record_thread (struct thread_db_info *info,
1319 struct thread_info *tp,
1320 ptid_t ptid, const td_thrhandle_t *th_p,
1321 const td_thrinfo_t *ti_p)
1323 /* A thread ID of zero may mean the thread library has not
1324 initialized yet. Leave private == NULL until the thread library
1326 if (ti_p->ti_tid == 0)
1329 /* Construct the thread's private data. */
1330 thread_db_thread_info *priv = new thread_db_thread_info;
1333 priv->tid = ti_p->ti_tid;
1334 update_thread_state (priv, ti_p);
1336 /* Add the thread to GDB's thread list. If we already know about a
1337 thread with this PTID, but it's marked exited, then the kernel
1338 reused the tid of an old thread. */
1339 if (tp == NULL || tp->state == THREAD_EXITED)
1340 tp = add_thread_with_info (ptid, priv);
1342 tp->priv.reset (priv);
1344 if (target_has_execution)
1345 check_thread_signals ();
1351 thread_db_target::detach (inferior *inf, int from_tty)
1353 delete_thread_db_info (inf->pid);
1355 beneath ()->detach (inf, from_tty);
1357 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1359 /* If there are no more processes using libpthread, detach the
1360 thread_db target ops. */
1361 if (!thread_db_list)
1362 unpush_target (this);
1366 thread_db_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
1369 struct thread_db_info *info;
1371 ptid = beneath ()->wait (ptid, ourstatus, options);
1373 switch (ourstatus->kind)
1375 case TARGET_WAITKIND_IGNORE:
1376 case TARGET_WAITKIND_EXITED:
1377 case TARGET_WAITKIND_THREAD_EXITED:
1378 case TARGET_WAITKIND_SIGNALLED:
1382 info = get_thread_db_info (ptid_get_pid (ptid));
1384 /* If this process isn't using thread_db, we're done. */
1388 if (ourstatus->kind == TARGET_WAITKIND_EXECD)
1390 /* New image, it may or may not end up using thread_db. Assume
1391 not unless we find otherwise. */
1392 delete_thread_db_info (ptid_get_pid (ptid));
1393 if (!thread_db_list)
1394 unpush_target (&the_thread_db_target);
1399 /* Fill in the thread's user-level thread id and status. */
1400 thread_from_lwp (ptid);
1406 thread_db_target::mourn_inferior ()
1408 delete_thread_db_info (ptid_get_pid (inferior_ptid));
1410 beneath ()->mourn_inferior ();
1412 /* Detach thread_db target ops. */
1413 if (!thread_db_list)
1414 unpush_target (&the_thread_db_target);
1417 struct callback_data
1419 struct thread_db_info *info;
1424 find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
1429 struct thread_info *tp;
1430 struct callback_data *cb_data = (struct callback_data *) data;
1431 struct thread_db_info *info = cb_data->info;
1433 err = info->td_thr_get_info_p (th_p, &ti);
1435 error (_("find_new_threads_callback: cannot get thread info: %s"),
1436 thread_db_err_str (err));
1438 if (ti.ti_lid == -1)
1440 /* A thread with kernel thread ID -1 is either a thread that
1441 exited and was joined, or a thread that is being created but
1442 hasn't started yet, and that is reusing the tcb/stack of a
1443 thread that previously exited and was joined. (glibc marks
1444 terminated and joined threads with kernel thread ID -1. See
1446 if (libthread_db_debug)
1447 fprintf_unfiltered (gdb_stdlog,
1448 "thread_db: skipping exited and "
1449 "joined thread (0x%lx)\n",
1450 (unsigned long) ti.ti_tid);
1456 /* A thread ID of zero means that this is the main thread, but
1457 glibc has not yet initialized thread-local storage and the
1458 pthread library. We do not know what the thread's TID will
1461 /* In that case, we're not stopped in a fork syscall and don't
1462 need this glibc bug workaround. */
1463 info->need_stale_parent_threads_check = 0;
1468 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1469 bit expensive, as it needs to open /proc/pid/status, so try to
1470 avoid doing the work if we know we don't have to. */
1471 if (info->need_stale_parent_threads_check)
1473 int tgid = linux_proc_get_tgid (ti.ti_lid);
1475 if (tgid != -1 && tgid != info->pid)
1479 ptid = ptid_build (info->pid, ti.ti_lid, 0);
1480 tp = find_thread_ptid (ptid);
1481 if (tp == NULL || tp->priv == NULL)
1482 record_thread (info, tp, ptid, th_p, &ti);
1487 /* Helper for thread_db_find_new_threads_2.
1488 Returns number of new threads found. */
1491 find_new_threads_once (struct thread_db_info *info, int iteration,
1494 struct callback_data data;
1495 td_err_e err = TD_ERR;
1498 data.new_threads = 0;
1500 /* See comment in thread_db_update_thread_list. */
1501 gdb_assert (info->td_ta_thr_iter_p != NULL);
1505 /* Iterate over all user-space threads to discover new threads. */
1506 err = info->td_ta_thr_iter_p (info->thread_agent,
1507 find_new_threads_callback,
1510 TD_THR_LOWEST_PRIORITY,
1512 TD_THR_ANY_USER_FLAGS);
1514 CATCH (except, RETURN_MASK_ERROR)
1516 if (libthread_db_debug)
1518 exception_fprintf (gdb_stdlog, except,
1519 "Warning: find_new_threads_once: ");
1524 if (libthread_db_debug)
1526 fprintf_unfiltered (gdb_stdlog,
1527 _("Found %d new threads in iteration %d.\n"),
1528 data.new_threads, iteration);
1534 return data.new_threads;
1537 /* Search for new threads, accessing memory through stopped thread
1538 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1539 searches in a row do not discover any new threads. */
1542 thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new)
1544 td_err_e err = TD_OK;
1545 struct thread_db_info *info;
1548 info = get_thread_db_info (ptid_get_pid (ptid));
1550 /* Access an lwp we know is stopped. */
1551 info->proc_handle.ptid = ptid;
1555 /* Require 4 successive iterations which do not find any new threads.
1556 The 4 is a heuristic: there is an inherent race here, and I have
1557 seen that 2 iterations in a row are not always sufficient to
1558 "capture" all threads. */
1559 for (i = 0, loop = 0; loop < 4 && err == TD_OK; ++i, ++loop)
1560 if (find_new_threads_once (info, i, &err) != 0)
1562 /* Found some new threads. Restart the loop from beginning. */
1567 find_new_threads_once (info, 0, &err);
1570 error (_("Cannot find new threads: %s"), thread_db_err_str (err));
1574 thread_db_find_new_threads_1 (ptid_t ptid)
1576 thread_db_find_new_threads_2 (ptid, 0);
1579 /* Implement the to_update_thread_list target method for this
1583 thread_db_target::update_thread_list ()
1585 struct thread_db_info *info;
1586 struct inferior *inf;
1592 struct thread_info *thread;
1597 info = get_thread_db_info (inf->pid);
1601 thread = any_live_thread_of_process (inf->pid);
1602 if (thread == NULL || thread->executing)
1605 /* It's best to avoid td_ta_thr_iter if possible. That walks
1606 data structures in the inferior's address space that may be
1607 corrupted, or, if the target is running, the list may change
1608 while we walk it. In the latter case, it's possible that a
1609 thread exits just at the exact time that causes GDB to get
1610 stuck in an infinite loop. To avoid pausing all threads
1611 whenever the core wants to refresh the thread list, we
1612 instead use thread_from_lwp immediately when we see an LWP
1613 stop. That uses thread_db entry points that do not walk
1614 libpthread's thread list, so should be safe, as well as more
1616 if (target_has_execution_1 (thread->ptid))
1619 thread_db_find_new_threads_1 (thread->ptid);
1622 /* Give the beneath target a chance to do extra processing. */
1623 this->beneath ()->update_thread_list ();
1627 thread_db_target::pid_to_str (ptid_t ptid)
1629 struct thread_info *thread_info = find_thread_ptid (ptid);
1631 if (thread_info != NULL && thread_info->priv != NULL)
1633 static char buf[64];
1634 thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
1636 snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
1637 (unsigned long) priv->tid, ptid_get_lwp (ptid));
1642 return beneath ()->pid_to_str (ptid);
1645 /* Return a string describing the state of the thread specified by
1649 thread_db_target::extra_thread_info (thread_info *info)
1651 if (info->priv == NULL)
1654 thread_db_thread_info *priv = get_thread_db_thread_info (info);
1662 /* Return pointer to the thread_info struct which corresponds to
1663 THREAD_HANDLE (having length HANDLE_LEN). */
1666 thread_db_target::thread_handle_to_thread_info (const gdb_byte *thread_handle,
1670 struct thread_info *tp;
1671 thread_t handle_tid;
1673 /* Thread handle sizes must match in order to proceed. We don't use an
1674 assert here because the resulting internal error will cause GDB to
1675 exit. This isn't necessarily an internal error due to the possibility
1676 of garbage being passed as the thread handle via the python interface. */
1677 if (handle_len != sizeof (handle_tid))
1678 error (_("Thread handle size mismatch: %d vs %zu (from libthread_db)"),
1679 handle_len, sizeof (handle_tid));
1681 handle_tid = * (const thread_t *) thread_handle;
1683 ALL_NON_EXITED_THREADS (tp)
1685 thread_db_thread_info *priv = get_thread_db_thread_info (tp);
1687 if (tp->inf == inf && priv != NULL && handle_tid == priv->tid)
1694 /* Get the address of the thread local variable in load module LM which
1695 is stored at OFFSET within the thread local storage for thread PTID. */
1698 thread_db_target::get_thread_local_address (ptid_t ptid,
1702 struct thread_info *thread_info;
1704 /* Find the matching thread. */
1705 thread_info = find_thread_ptid (ptid);
1707 /* We may not have discovered the thread yet. */
1708 if (thread_info != NULL && thread_info->priv == NULL)
1709 thread_info = thread_from_lwp (ptid);
1711 if (thread_info != NULL && thread_info->priv != NULL)
1715 thread_db_info *info = get_thread_db_info (ptid_get_pid (ptid));
1716 thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
1718 /* Finally, get the address of the variable. */
1721 /* glibc doesn't provide the needed interface. */
1722 if (!info->td_thr_tls_get_addr_p)
1723 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
1724 _("No TLS library support"));
1726 /* Note the cast through uintptr_t: this interface only works if
1727 a target address fits in a psaddr_t, which is a host pointer.
1728 So a 32-bit debugger can not access 64-bit TLS through this. */
1729 err = info->td_thr_tls_get_addr_p (&priv->th,
1730 (psaddr_t)(uintptr_t) lm,
1735 /* If glibc doesn't provide the needed interface throw an error
1736 that LM is zero - normally cases it should not be. */
1737 if (!info->td_thr_tlsbase_p)
1738 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
1739 _("TLS load module not found"));
1741 /* This code path handles the case of -static -pthread executables:
1742 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1743 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1744 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1745 The constant number 1 depends on GNU __libc_setup_tls
1746 initialization of l_tls_modid to 1. */
1747 err = info->td_thr_tlsbase_p (&priv->th, 1, &address);
1748 address = (char *) address + offset;
1751 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1752 /* The memory hasn't been allocated, yet. */
1753 if (err == TD_NOTALLOC)
1754 /* Now, if libthread_db provided the initialization image's
1755 address, we *could* try to build a non-lvalue value from
1756 the initialization image. */
1757 throw_error (TLS_NOT_ALLOCATED_YET_ERROR,
1758 _("TLS not allocated yet"));
1761 /* Something else went wrong. */
1763 throw_error (TLS_GENERIC_ERROR,
1764 (("%s")), thread_db_err_str (err));
1766 /* Cast assuming host == target. Joy. */
1767 /* Do proper sign extension for the target. */
1768 gdb_assert (exec_bfd);
1769 return (bfd_get_sign_extend_vma (exec_bfd) > 0
1770 ? (CORE_ADDR) (intptr_t) address
1771 : (CORE_ADDR) (uintptr_t) address);
1774 return beneath ()->get_thread_local_address (ptid, lm, offset);
1777 /* Implement the to_get_ada_task_ptid target method for this target. */
1780 thread_db_target::get_ada_task_ptid (long lwp, long thread)
1782 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1783 return ptid_build (ptid_get_pid (inferior_ptid), lwp, 0);
1787 thread_db_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
1789 struct thread_db_info *info;
1791 if (ptid_equal (ptid, minus_one_ptid))
1792 info = get_thread_db_info (ptid_get_pid (inferior_ptid));
1794 info = get_thread_db_info (ptid_get_pid (ptid));
1796 /* This workaround is only needed for child fork lwps stopped in a
1797 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1798 workaround can be disabled. */
1800 info->need_stale_parent_threads_check = 0;
1802 beneath ()->resume (ptid, step, signo);
1805 /* std::sort helper function for info_auto_load_libthread_db, sort the
1806 thread_db_info pointers primarily by their FILENAME and secondarily by their
1807 PID, both in ascending order. */
1810 info_auto_load_libthread_db_compare (const struct thread_db_info *a,
1811 const struct thread_db_info *b)
1815 retval = strcmp (a->filename, b->filename);
1819 return a->pid < b->pid;
1822 /* Implement 'info auto-load libthread-db'. */
1825 info_auto_load_libthread_db (const char *args, int from_tty)
1827 struct ui_out *uiout = current_uiout;
1828 const char *cs = args ? args : "";
1829 struct thread_db_info *info;
1830 unsigned unique_filenames;
1831 size_t max_filename_len, pids_len;
1834 cs = skip_spaces (cs);
1836 error (_("'info auto-load libthread-db' does not accept any parameters"));
1838 std::vector<struct thread_db_info *> array;
1839 for (info = thread_db_list; info; info = info->next)
1840 if (info->filename != NULL)
1841 array.push_back (info);
1843 /* Sort ARRAY by filenames and PIDs. */
1844 std::sort (array.begin (), array.end (),
1845 info_auto_load_libthread_db_compare);
1847 /* Calculate the number of unique filenames (rows) and the maximum string
1848 length of PIDs list for the unique filenames (columns). */
1850 unique_filenames = 0;
1851 max_filename_len = 0;
1853 for (i = 0; i < array.size (); i++)
1855 int pid = array[i]->pid;
1856 size_t this_pid_len;
1858 for (this_pid_len = 0; pid != 0; pid /= 10)
1861 if (i == 0 || strcmp (array[i - 1]->filename, array[i]->filename) != 0)
1864 max_filename_len = std::max (max_filename_len,
1865 strlen (array[i]->filename));
1868 pids_len -= strlen (", ");
1871 pids_len += this_pid_len + strlen (", ");
1874 pids_len -= strlen (", ");
1876 /* Table header shifted right by preceding "libthread-db: " would not match
1878 if (array.size () > 0 && args == auto_load_info_scripts_pattern_nl)
1882 ui_out_emit_table table_emitter (uiout, 2, unique_filenames,
1883 "LinuxThreadDbTable");
1885 uiout->table_header (max_filename_len, ui_left, "filename", "Filename");
1886 uiout->table_header (pids_len, ui_left, "PIDs", "Pids");
1887 uiout->table_body ();
1889 /* Note I is incremented inside the cycle, not at its end. */
1890 for (i = 0; i < array.size ();)
1892 ui_out_emit_tuple tuple_emitter (uiout, NULL);
1895 uiout->field_string ("filename", info->filename);
1898 while (i < array.size () && strcmp (info->filename,
1899 array[i]->filename) == 0)
1903 string_appendf (pids, "%u", array[i]->pid);
1907 uiout->field_string ("pids", pids.c_str ());
1914 uiout->message (_("No auto-loaded libthread-db.\n"));
1917 /* Implement 'maintenance check libthread-db'. */
1920 maintenance_check_libthread_db (const char *args, int from_tty)
1922 int inferior_pid = ptid_get_pid (inferior_ptid);
1923 struct thread_db_info *info;
1925 if (inferior_pid == 0)
1926 error (_("No inferior running"));
1928 info = get_thread_db_info (inferior_pid);
1930 error (_("No libthread_db loaded"));
1932 check_thread_db (info, true);
1936 _initialize_thread_db (void)
1938 /* Defer loading of libthread_db.so until inferior is running.
1939 This allows gdb to load correct libthread_db for a given
1940 executable -- there could be multiple versions of glibc,
1941 and until there is a running inferior, we can't tell which
1942 libthread_db is the correct one to load. */
1944 libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
1946 add_setshow_optional_filename_cmd ("libthread-db-search-path",
1948 &libthread_db_search_path, _("\
1949 Set search path for libthread_db."), _("\
1950 Show the current search path or libthread_db."), _("\
1951 This path is used to search for libthread_db to be loaded into \
1953 Its value is a colon (':') separate list of directories to search.\n\
1954 Setting the search path to an empty list resets it to its default value."),
1955 set_libthread_db_search_path,
1957 &setlist, &showlist);
1959 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance,
1960 &libthread_db_debug, _("\
1961 Set libthread-db debugging."), _("\
1962 Show libthread-db debugging."), _("\
1963 When non-zero, libthread-db debugging is enabled."),
1965 show_libthread_db_debug,
1966 &setdebuglist, &showdebuglist);
1968 add_setshow_boolean_cmd ("libthread-db", class_support,
1969 &auto_load_thread_db, _("\
1970 Enable or disable auto-loading of inferior specific libthread_db."), _("\
1971 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
1972 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
1973 locations to load libthread_db compatible with the inferior.\n\
1974 Standard system libthread_db still gets loaded even with this option off.\n\
1975 This options has security implications for untrusted inferiors."),
1976 NULL, show_auto_load_thread_db,
1977 auto_load_set_cmdlist_get (),
1978 auto_load_show_cmdlist_get ());
1980 add_cmd ("libthread-db", class_info, info_auto_load_libthread_db,
1981 _("Print the list of loaded inferior specific libthread_db.\n\
1982 Usage: info auto-load libthread-db"),
1983 auto_load_info_cmdlist_get ());
1985 add_cmd ("libthread-db", class_maintenance,
1986 maintenance_check_libthread_db, _("\
1987 Run integrity checks on the current inferior's libthread_db."),
1988 &maintenancechecklist);
1990 add_setshow_boolean_cmd ("check-libthread-db",
1992 &check_thread_db_on_load, _("\
1993 Set whether to check libthread_db at load time."), _("\
1994 Show whether to check libthread_db at load time."), _("\
1995 If enabled GDB will run integrity checks on inferior specific libthread_db\n\
1996 as they are loaded."),
1999 &maintenance_set_cmdlist,
2000 &maintenance_show_cmdlist);
2002 /* Add ourselves to objfile event chain. */
2003 gdb::observers::new_objfile.attach (thread_db_new_objfile);
2005 /* Add ourselves to inferior_created event chain.
2006 This is needed to handle debugging statically linked programs where
2007 the new_objfile observer won't get called for libpthread. */
2008 gdb::observers::inferior_created.attach (thread_db_inferior_created);