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
88 const target_info &info () const override
89 { return thread_db_target_info; }
91 strata stratum () const override { return thread_stratum; }
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 static char *libthread_db_search_path;
112 /* Set to non-zero if thread_db auto-loading is enabled
113 by the "set auto-load libthread-db" command. */
114 static int auto_load_thread_db = 1;
116 /* Set to non-zero if load-time libthread_db tests have been enabled
117 by the "maintenence set check-libthread-db" command. */
118 static int check_thread_db_on_load = 0;
120 /* "show" command for the auto_load_thread_db configuration variable. */
123 show_auto_load_thread_db (struct ui_file *file, int from_tty,
124 struct cmd_list_element *c, const char *value)
126 fprintf_filtered (file, _("Auto-loading of inferior specific libthread_db "
132 set_libthread_db_search_path (const char *ignored, int from_tty,
133 struct cmd_list_element *c)
135 if (*libthread_db_search_path == '\0')
137 xfree (libthread_db_search_path);
138 libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
142 /* If non-zero, print details of libthread_db processing. */
144 static unsigned int libthread_db_debug;
147 show_libthread_db_debug (struct ui_file *file, int from_tty,
148 struct cmd_list_element *c, const char *value)
150 fprintf_filtered (file, _("libthread-db debugging is %s.\n"), value);
153 /* If we're running on GNU/Linux, we must explicitly attach to any new
156 /* This module's target vector. */
157 static thread_db_target the_thread_db_target;
159 /* Non-zero if we have determined the signals used by the threads
161 static int thread_signals;
162 static sigset_t thread_stop_set;
163 static sigset_t thread_print_set;
165 struct thread_db_info
167 struct thread_db_info *next;
169 /* Process id this object refers to. */
172 /* Handle from dlopen for libthread_db.so. */
175 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
176 HANDLE. It may be NULL for system library. */
179 /* Structure that identifies the child process for the
180 <proc_service.h> interface. */
181 struct ps_prochandle proc_handle;
183 /* Connection to the libthread_db library. */
184 td_thragent_t *thread_agent;
186 /* True if we need to apply the workaround for glibc/BZ5983. When
187 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
188 list, nptl_db returns the parent's threads in addition to the new
189 (single) child thread. If this flag is set, we do extra work to
190 be able to ignore such stale entries. */
191 int need_stale_parent_threads_check;
193 /* Pointers to the libthread_db functions. */
195 td_init_ftype *td_init_p;
196 td_ta_new_ftype *td_ta_new_p;
197 td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p;
198 td_ta_thr_iter_ftype *td_ta_thr_iter_p;
199 td_thr_get_info_ftype *td_thr_get_info_p;
200 td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p;
201 td_thr_tlsbase_ftype *td_thr_tlsbase_p;
204 /* List of known processes using thread_db, and the required
206 struct thread_db_info *thread_db_list;
208 static void thread_db_find_new_threads_1 (thread_info *stopped);
209 static void thread_db_find_new_threads_2 (thread_info *stopped,
212 static void check_thread_signals (void);
214 static struct thread_info *record_thread
215 (struct thread_db_info *info, struct thread_info *tp,
216 ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p);
218 /* Add the current inferior to the list of processes using libpthread.
219 Return a pointer to the newly allocated object that was added to
220 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
223 static struct thread_db_info *
224 add_thread_db_info (void *handle)
226 struct thread_db_info *info = XCNEW (struct thread_db_info);
228 info->pid = inferior_ptid.pid ();
229 info->handle = handle;
231 /* The workaround works by reading from /proc/pid/status, so it is
232 disabled for core files. */
233 if (target_has_execution)
234 info->need_stale_parent_threads_check = 1;
236 info->next = thread_db_list;
237 thread_db_list = info;
242 /* Return the thread_db_info object representing the bookkeeping
243 related to process PID, if any; NULL otherwise. */
245 static struct thread_db_info *
246 get_thread_db_info (int pid)
248 struct thread_db_info *info;
250 for (info = thread_db_list; info; info = info->next)
251 if (pid == info->pid)
257 /* When PID has exited or has been detached, we no longer want to keep
258 track of it as using libpthread. Call this function to discard
259 thread_db related info related to PID. Note that this closes
260 LIBTHREAD_DB_SO's dlopen'ed handle. */
263 delete_thread_db_info (int pid)
265 struct thread_db_info *info, *info_prev;
269 for (info = thread_db_list; info; info_prev = info, info = info->next)
270 if (pid == info->pid)
276 if (info->handle != NULL)
277 dlclose (info->handle);
279 xfree (info->filename);
282 info_prev->next = info->next;
284 thread_db_list = info->next;
289 /* Use "struct private_thread_info" to cache thread state. This is
290 a substantial optimization. */
292 struct thread_db_thread_info : public private_thread_info
294 /* Flag set when we see a TD_DEATH event for this thread. */
297 /* Cached thread state. */
298 td_thrhandle_t th {};
302 static thread_db_thread_info *
303 get_thread_db_thread_info (thread_info *thread)
305 return static_cast<thread_db_thread_info *> (thread->priv.get ());
309 thread_db_err_str (td_err_e err)
316 return "generic 'call succeeded'";
318 return "generic error";
320 return "no thread to satisfy query";
322 return "no sync handle to satisfy query";
324 return "no LWP to satisfy query";
326 return "invalid process handle";
328 return "invalid thread handle";
330 return "invalid synchronization handle";
332 return "invalid thread agent";
334 return "invalid key";
336 return "no event message for getmsg";
338 return "FPU register set not available";
340 return "application not linked with libthread";
342 return "requested event is not supported";
344 return "capability not available";
346 return "debugger service failed";
348 return "operation not applicable to";
350 return "no thread-specific data for this thread";
352 return "malloc failed";
354 return "only part of register set was written/read";
356 return "X register set not available for this thread";
357 #ifdef THREAD_DB_HAS_TD_NOTALLOC
359 return "thread has not yet allocated TLS for given module";
361 #ifdef THREAD_DB_HAS_TD_VERSION
363 return "versions of libpthread and libthread_db do not match";
365 #ifdef THREAD_DB_HAS_TD_NOTLS
367 return "there is no TLS segment in the given module";
370 snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
375 /* Fetch the user-level thread id of PTID. STOPPED is a stopped
376 thread that we can use to access memory. */
378 static struct thread_info *
379 thread_from_lwp (thread_info *stopped, ptid_t ptid)
384 struct thread_db_info *info;
385 struct thread_info *tp;
387 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
390 /* This ptid comes from linux-nat.c, which should always fill in the
392 gdb_assert (ptid.lwp () != 0);
394 info = get_thread_db_info (ptid.pid ());
396 /* Access an lwp we know is stopped. */
397 info->proc_handle.thread = stopped;
398 err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid.lwp (),
401 error (_("Cannot find user-level thread for LWP %ld: %s"),
402 ptid.lwp (), thread_db_err_str (err));
404 err = info->td_thr_get_info_p (&th, &ti);
406 error (_("thread_get_info_callback: cannot get thread info: %s"),
407 thread_db_err_str (err));
409 /* Fill the cache. */
410 tp = find_thread_ptid (ptid);
411 return record_thread (info, tp, ptid, &th, &ti);
415 /* See linux-nat.h. */
418 thread_db_notice_clone (ptid_t parent, ptid_t child)
420 struct thread_db_info *info;
422 info = get_thread_db_info (child.pid ());
427 thread_info *stopped = find_thread_ptid (parent);
429 thread_from_lwp (stopped, child);
431 /* If we do not know about the main thread's pthread info yet, this
432 would be a good time to find it. */
433 thread_from_lwp (stopped, parent);
438 verbose_dlsym (void *handle, const char *name)
440 void *sym = dlsym (handle, name);
442 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
447 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
448 return 1 if this version is lower (and not equal) to
449 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
452 inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min)
454 struct bound_minimal_symbol version_msym;
455 CORE_ADDR version_addr;
456 gdb::unique_xmalloc_ptr<char> version;
457 int err, got, retval = 0;
459 version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL);
460 if (version_msym.minsym == NULL)
463 version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym);
464 got = target_read_string (version_addr, &version, 32, &err);
465 if (err == 0 && memchr (version.get (), 0, got) == version.get () + got - 1)
469 retval = (sscanf (version.get (), "%d.%d", &major, &minor) == 2
470 && (major < ver_major_min
471 || (major == ver_major_min && minor < ver_minor_min)));
477 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
480 Return 1 if the caller should abort libthread_db initialization. Return 0
484 thread_db_find_new_threads_silently (thread_info *stopped)
489 thread_db_find_new_threads_2 (stopped, true);
492 CATCH (except, RETURN_MASK_ERROR)
494 if (libthread_db_debug)
495 exception_fprintf (gdb_stdlog, except,
496 "Warning: thread_db_find_new_threads_silently: ");
498 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
499 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
500 where calls to td_thr_get_info fail with TD_ERR for statically linked
501 executables if td_thr_get_info is called before glibc has initialized
504 If the nptl bug is NOT present in the inferior and still thread_db
505 reports an error return 1. It means the inferior has corrupted thread
506 list and GDB should fall back only to LWPs.
508 If the nptl bug is present in the inferior return 0 to silently ignore
509 such errors, and let gdb enumerate threads again later. In such case
510 GDB cannot properly display LWPs if the inferior thread list is
511 corrupted. For core files it does not apply, no 'later enumeration'
514 if (!target_has_execution || !inferior_has_bug ("nptl_version", 2, 7))
516 exception_fprintf (gdb_stderr, except,
517 _("Warning: couldn't activate thread debugging "
518 "using libthread_db: "));
527 /* Lookup a library in which given symbol resides.
528 Note: this is looking in GDB process, not in the inferior.
529 Returns library name, or NULL. */
532 dladdr_to_soname (const void *addr)
536 if (dladdr (addr, &info) != 0)
537 return info.dli_fname;
541 /* State for check_thread_db_callback. */
543 struct check_thread_db_info
545 /* The libthread_db under test. */
546 struct thread_db_info *info;
548 /* True if progress should be logged. */
551 /* True if the callback was called. */
554 /* Name of last libthread_db function called. */
555 const char *last_call;
557 /* Value returned by last libthread_db call. */
558 td_err_e last_result;
561 static struct check_thread_db_info *tdb_testinfo;
563 /* Callback for check_thread_db. */
566 check_thread_db_callback (const td_thrhandle_t *th, void *arg)
568 gdb_assert (tdb_testinfo != NULL);
569 tdb_testinfo->threads_seen = true;
571 #define LOG(fmt, args...) \
574 if (tdb_testinfo->log_progress) \
576 debug_printf (fmt, ## args); \
577 gdb_flush (gdb_stdlog); \
582 #define CHECK_1(expr, args...) \
587 LOG (" ... FAIL!\n"); \
593 #define CHECK(expr) \
594 CHECK_1 (expr, "(%s) == false", #expr)
596 #define CALL_UNCHECKED(func, args...) \
599 tdb_testinfo->last_call = #func; \
600 tdb_testinfo->last_result \
601 = tdb_testinfo->info->func ## _p (args); \
605 #define CHECK_CALL() \
606 CHECK_1 (tdb_testinfo->last_result == TD_OK, \
607 _("%s failed: %s"), \
608 tdb_testinfo->last_call, \
609 thread_db_err_str (tdb_testinfo->last_result)) \
611 #define CALL(func, args...) \
614 CALL_UNCHECKED (func, args); \
621 /* Check td_ta_thr_iter passed consistent arguments. */
623 CHECK (arg == (void *) tdb_testinfo);
624 CHECK (th->th_ta_p == tdb_testinfo->info->thread_agent);
626 LOG (" %s", core_addr_to_string_nz ((CORE_ADDR) th->th_unique));
628 /* Check td_thr_get_info. */
630 CALL (td_thr_get_info, th, &ti);
632 LOG (" => %d", ti.ti_lid);
634 CHECK (ti.ti_ta_p == th->th_ta_p);
635 CHECK (ti.ti_tid == (thread_t) th->th_unique);
637 /* Check td_ta_map_lwp2thr. */
639 memset (&th2, 23, sizeof (td_thrhandle_t));
640 CALL_UNCHECKED (td_ta_map_lwp2thr, th->th_ta_p, ti.ti_lid, &th2);
642 if (tdb_testinfo->last_result == TD_ERR && !target_has_execution)
644 /* Some platforms require execution for td_ta_map_lwp2thr. */
645 LOG (_("; can't map_lwp2thr"));
651 LOG (" => %s", core_addr_to_string_nz ((CORE_ADDR) th2.th_unique));
653 CHECK (memcmp (th, &th2, sizeof (td_thrhandle_t)) == 0);
656 /* Attempt TLS access. Assuming errno is TLS, this calls
657 thread_db_get_thread_local_address, which in turn calls
658 td_thr_tls_get_addr for live inferiors or td_thr_tlsbase
659 for core files. This test is skipped if the thread has
660 not been recorded; proceeding in that case would result
661 in the test having the side-effect of noticing threads
664 Note that in glibc's libthread_db td_thr_tls_get_addr is
665 a thin wrapper around td_thr_tlsbase; this check always
666 hits the bulk of the code.
668 Note also that we don't actually check any libthread_db
669 calls are made, we just assume they were; future changes
670 to how GDB accesses TLS could result in this passing
671 without exercising the calls it's supposed to. */
672 ptid_t ptid = ptid_t (tdb_testinfo->info->pid, ti.ti_lid, 0);
673 struct thread_info *thread_info = find_thread_ptid (ptid);
674 if (thread_info != NULL && thread_info->priv != NULL)
678 scoped_restore_current_thread restore_current_thread;
679 switch_to_thread (ptid);
681 expression_up expr = parse_expression ("(int) errno");
682 struct value *val = evaluate_expression (expr.get ());
684 if (tdb_testinfo->log_progress)
686 struct value_print_options opts;
688 get_user_print_options (&opts);
690 value_print (val, gdb_stdlog, &opts);
699 #undef CALL_UNCHECKED
706 /* Run integrity checks on the dlopen()ed libthread_db described by
707 INFO. Returns true on success, displays a warning and returns
708 false on failure. Logs progress messages to gdb_stdlog during
709 the test if LOG_PROGRESS is true. */
712 check_thread_db (struct thread_db_info *info, bool log_progress)
714 bool test_passed = true;
717 debug_printf (_("Running libthread_db integrity checks:\n"));
719 /* GDB avoids using td_ta_thr_iter wherever possible (see comment
720 in try_thread_db_load_1 below) so in order to test it we may
721 have to locate it ourselves. */
722 td_ta_thr_iter_ftype *td_ta_thr_iter_p = info->td_ta_thr_iter_p;
723 if (td_ta_thr_iter_p == NULL)
725 void *thr_iter = verbose_dlsym (info->handle, "td_ta_thr_iter");
726 if (thr_iter == NULL)
729 td_ta_thr_iter_p = (td_ta_thr_iter_ftype *) thr_iter;
732 /* Set up the test state we share with the callback. */
733 gdb_assert (tdb_testinfo == NULL);
734 struct check_thread_db_info tdb_testinfo_buf;
735 tdb_testinfo = &tdb_testinfo_buf;
737 memset (tdb_testinfo, 0, sizeof (struct check_thread_db_info));
738 tdb_testinfo->info = info;
739 tdb_testinfo->log_progress = log_progress;
741 /* td_ta_thr_iter shouldn't be used on running processes. Note that
742 it's possible the inferior will stop midway through modifying one
743 of its thread lists, in which case the check will spuriously
745 linux_stop_and_wait_all_lwps ();
749 td_err_e err = td_ta_thr_iter_p (info->thread_agent,
750 check_thread_db_callback,
753 TD_THR_LOWEST_PRIORITY,
755 TD_THR_ANY_USER_FLAGS);
758 error (_("td_ta_thr_iter failed: %s"), thread_db_err_str (err));
760 if (!tdb_testinfo->threads_seen)
761 error (_("no threads seen"));
763 CATCH (except, RETURN_MASK_ERROR)
765 if (warning_pre_print)
766 fputs_unfiltered (warning_pre_print, gdb_stderr);
768 exception_fprintf (gdb_stderr, except,
769 _("libthread_db integrity checks failed: "));
775 if (test_passed && log_progress)
776 debug_printf (_("libthread_db integrity checks passed.\n"));
780 linux_unstop_all_lwps ();
785 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
787 Failure could happen if libthread_db does not have symbols we expect,
788 or when it refuses to work with the current inferior (e.g. due to
789 version mismatch between libthread_db and libpthread). */
792 try_thread_db_load_1 (struct thread_db_info *info)
796 /* Initialize pointers to the dynamic library functions we will use.
797 Essential functions first. */
799 #define TDB_VERBOSE_DLSYM(info, func) \
800 info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
802 #define TDB_DLSYM(info, func) \
803 info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
812 CHK (TDB_VERBOSE_DLSYM (info, td_init));
814 err = info->td_init_p ();
817 warning (_("Cannot initialize libthread_db: %s"),
818 thread_db_err_str (err));
822 CHK (TDB_VERBOSE_DLSYM (info, td_ta_new));
824 /* Initialize the structure that identifies the child process. */
825 info->proc_handle.thread = inferior_thread ();
827 /* Now attempt to open a connection to the thread library. */
828 err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
831 if (libthread_db_debug)
832 fprintf_unfiltered (gdb_stdlog, _("td_ta_new failed: %s\n"),
833 thread_db_err_str (err));
838 #ifdef THREAD_DB_HAS_TD_VERSION
841 /* The errors above are not unexpected and silently ignored:
842 they just mean we haven't found correct version of
846 warning (_("td_ta_new failed: %s"), thread_db_err_str (err));
851 /* These are essential. */
852 CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr));
853 CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info));
855 /* These are not essential. */
856 TDB_DLSYM (info, td_thr_tls_get_addr);
857 TDB_DLSYM (info, td_thr_tlsbase);
859 /* It's best to avoid td_ta_thr_iter if possible. That walks data
860 structures in the inferior's address space that may be corrupted,
861 or, if the target is running, may change while we walk them. If
862 there's execution (and /proc is mounted), then we're already
863 attached to all LWPs. Use thread_from_lwp, which uses
864 td_ta_map_lwp2thr instead, which does not walk the thread list.
866 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
867 currently on core targets, as it uses ptrace directly. */
868 if (target_has_execution
869 && linux_proc_task_list_dir_exists (inferior_ptid.pid ()))
870 info->td_ta_thr_iter_p = NULL;
872 CHK (TDB_VERBOSE_DLSYM (info, td_ta_thr_iter));
874 #undef TDB_VERBOSE_DLSYM
878 /* Run integrity checks if requested. */
879 if (check_thread_db_on_load)
881 if (!check_thread_db (info, libthread_db_debug))
885 if (info->td_ta_thr_iter_p == NULL)
888 int pid = inferior_ptid.pid ();
889 thread_info *curr_thread = inferior_thread ();
891 linux_stop_and_wait_all_lwps ();
894 if (lp->ptid.pid () == pid)
895 thread_from_lwp (curr_thread, lp->ptid);
897 linux_unstop_all_lwps ();
899 else if (thread_db_find_new_threads_silently (inferior_thread ()) != 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 (inferior_ptid.pid ());
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 (inferior_ptid.pid ());
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 (inferior_ptid.pid (), 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.pid ());
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.pid ());
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 (find_thread_ptid (ptid), ptid);
1406 thread_db_target::mourn_inferior ()
1408 delete_thread_db_info (inferior_ptid.pid ());
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)
1428 struct thread_info *tp;
1429 struct callback_data *cb_data = (struct callback_data *) data;
1430 struct thread_db_info *info = cb_data->info;
1432 err = info->td_thr_get_info_p (th_p, &ti);
1434 error (_("find_new_threads_callback: cannot get thread info: %s"),
1435 thread_db_err_str (err));
1437 if (ti.ti_lid == -1)
1439 /* A thread with kernel thread ID -1 is either a thread that
1440 exited and was joined, or a thread that is being created but
1441 hasn't started yet, and that is reusing the tcb/stack of a
1442 thread that previously exited and was joined. (glibc marks
1443 terminated and joined threads with kernel thread ID -1. See
1445 if (libthread_db_debug)
1446 fprintf_unfiltered (gdb_stdlog,
1447 "thread_db: skipping exited and "
1448 "joined thread (0x%lx)\n",
1449 (unsigned long) ti.ti_tid);
1455 /* A thread ID of zero means that this is the main thread, but
1456 glibc has not yet initialized thread-local storage and the
1457 pthread library. We do not know what the thread's TID will
1460 /* In that case, we're not stopped in a fork syscall and don't
1461 need this glibc bug workaround. */
1462 info->need_stale_parent_threads_check = 0;
1467 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1468 bit expensive, as it needs to open /proc/pid/status, so try to
1469 avoid doing the work if we know we don't have to. */
1470 if (info->need_stale_parent_threads_check)
1472 int tgid = linux_proc_get_tgid (ti.ti_lid);
1474 if (tgid != -1 && tgid != info->pid)
1478 ptid_t ptid (info->pid, ti.ti_lid);
1479 tp = find_thread_ptid (ptid);
1480 if (tp == NULL || tp->priv == NULL)
1481 record_thread (info, tp, ptid, th_p, &ti);
1486 /* Helper for thread_db_find_new_threads_2.
1487 Returns number of new threads found. */
1490 find_new_threads_once (struct thread_db_info *info, int iteration,
1493 struct callback_data data;
1494 td_err_e err = TD_ERR;
1497 data.new_threads = 0;
1499 /* See comment in thread_db_update_thread_list. */
1500 gdb_assert (info->td_ta_thr_iter_p != NULL);
1504 /* Iterate over all user-space threads to discover new threads. */
1505 err = info->td_ta_thr_iter_p (info->thread_agent,
1506 find_new_threads_callback,
1509 TD_THR_LOWEST_PRIORITY,
1511 TD_THR_ANY_USER_FLAGS);
1513 CATCH (except, RETURN_MASK_ERROR)
1515 if (libthread_db_debug)
1517 exception_fprintf (gdb_stdlog, except,
1518 "Warning: find_new_threads_once: ");
1523 if (libthread_db_debug)
1525 fprintf_unfiltered (gdb_stdlog,
1526 _("Found %d new threads in iteration %d.\n"),
1527 data.new_threads, iteration);
1533 return data.new_threads;
1536 /* Search for new threads, accessing memory through stopped thread
1537 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1538 searches in a row do not discover any new threads. */
1541 thread_db_find_new_threads_2 (thread_info *stopped, bool until_no_new)
1543 td_err_e err = TD_OK;
1544 struct thread_db_info *info;
1547 info = get_thread_db_info (stopped->ptid.pid ());
1549 /* Access an lwp we know is stopped. */
1550 info->proc_handle.thread = stopped;
1554 /* Require 4 successive iterations which do not find any new threads.
1555 The 4 is a heuristic: there is an inherent race here, and I have
1556 seen that 2 iterations in a row are not always sufficient to
1557 "capture" all threads. */
1558 for (i = 0, loop = 0; loop < 4 && err == TD_OK; ++i, ++loop)
1559 if (find_new_threads_once (info, i, &err) != 0)
1561 /* Found some new threads. Restart the loop from beginning. */
1566 find_new_threads_once (info, 0, &err);
1569 error (_("Cannot find new threads: %s"), thread_db_err_str (err));
1573 thread_db_find_new_threads_1 (thread_info *stopped)
1575 thread_db_find_new_threads_2 (stopped, 0);
1578 /* Implement the to_update_thread_list target method for this
1582 thread_db_target::update_thread_list ()
1584 struct thread_db_info *info;
1588 for (inferior *inf : all_inferiors ())
1590 struct thread_info *thread;
1595 info = get_thread_db_info (inf->pid);
1599 thread = any_live_thread_of_inferior (inf);
1600 if (thread == NULL || thread->executing)
1603 /* It's best to avoid td_ta_thr_iter if possible. That walks
1604 data structures in the inferior's address space that may be
1605 corrupted, or, if the target is running, the list may change
1606 while we walk it. In the latter case, it's possible that a
1607 thread exits just at the exact time that causes GDB to get
1608 stuck in an infinite loop. To avoid pausing all threads
1609 whenever the core wants to refresh the thread list, we
1610 instead use thread_from_lwp immediately when we see an LWP
1611 stop. That uses thread_db entry points that do not walk
1612 libpthread's thread list, so should be safe, as well as more
1614 if (target_has_execution_1 (thread->ptid))
1617 thread_db_find_new_threads_1 (thread);
1620 /* Give the beneath target a chance to do extra processing. */
1621 this->beneath ()->update_thread_list ();
1625 thread_db_target::pid_to_str (ptid_t ptid)
1627 struct thread_info *thread_info = find_thread_ptid (ptid);
1629 if (thread_info != NULL && thread_info->priv != NULL)
1631 static char buf[64];
1632 thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
1634 snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
1635 (unsigned long) priv->tid, ptid.lwp ());
1640 return beneath ()->pid_to_str (ptid);
1643 /* Return a string describing the state of the thread specified by
1647 thread_db_target::extra_thread_info (thread_info *info)
1649 if (info->priv == NULL)
1652 thread_db_thread_info *priv = get_thread_db_thread_info (info);
1660 /* Return pointer to the thread_info struct which corresponds to
1661 THREAD_HANDLE (having length HANDLE_LEN). */
1664 thread_db_target::thread_handle_to_thread_info (const gdb_byte *thread_handle,
1668 thread_t handle_tid;
1670 /* Thread handle sizes must match in order to proceed. We don't use an
1671 assert here because the resulting internal error will cause GDB to
1672 exit. This isn't necessarily an internal error due to the possibility
1673 of garbage being passed as the thread handle via the python interface. */
1674 if (handle_len != sizeof (handle_tid))
1675 error (_("Thread handle size mismatch: %d vs %zu (from libthread_db)"),
1676 handle_len, sizeof (handle_tid));
1678 handle_tid = * (const thread_t *) thread_handle;
1680 for (thread_info *tp : inf->non_exited_threads ())
1682 thread_db_thread_info *priv = get_thread_db_thread_info (tp);
1684 if (priv != NULL && handle_tid == priv->tid)
1691 /* Get the address of the thread local variable in load module LM which
1692 is stored at OFFSET within the thread local storage for thread PTID. */
1695 thread_db_target::get_thread_local_address (ptid_t ptid,
1699 struct thread_info *thread_info;
1701 /* Find the matching thread. */
1702 thread_info = find_thread_ptid (ptid);
1704 /* We may not have discovered the thread yet. */
1705 if (thread_info != NULL && thread_info->priv == NULL)
1706 thread_info = thread_from_lwp (thread_info, ptid);
1708 if (thread_info != NULL && thread_info->priv != NULL)
1712 thread_db_info *info = get_thread_db_info (ptid.pid ());
1713 thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
1715 /* Finally, get the address of the variable. */
1718 /* glibc doesn't provide the needed interface. */
1719 if (!info->td_thr_tls_get_addr_p)
1720 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
1721 _("No TLS library support"));
1723 /* Note the cast through uintptr_t: this interface only works if
1724 a target address fits in a psaddr_t, which is a host pointer.
1725 So a 32-bit debugger can not access 64-bit TLS through this. */
1726 err = info->td_thr_tls_get_addr_p (&priv->th,
1727 (psaddr_t)(uintptr_t) lm,
1732 /* If glibc doesn't provide the needed interface throw an error
1733 that LM is zero - normally cases it should not be. */
1734 if (!info->td_thr_tlsbase_p)
1735 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
1736 _("TLS load module not found"));
1738 /* This code path handles the case of -static -pthread executables:
1739 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1740 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1741 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1742 The constant number 1 depends on GNU __libc_setup_tls
1743 initialization of l_tls_modid to 1. */
1744 err = info->td_thr_tlsbase_p (&priv->th, 1, &address);
1745 address = (char *) address + offset;
1748 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1749 /* The memory hasn't been allocated, yet. */
1750 if (err == TD_NOTALLOC)
1751 /* Now, if libthread_db provided the initialization image's
1752 address, we *could* try to build a non-lvalue value from
1753 the initialization image. */
1754 throw_error (TLS_NOT_ALLOCATED_YET_ERROR,
1755 _("TLS not allocated yet"));
1758 /* Something else went wrong. */
1760 throw_error (TLS_GENERIC_ERROR,
1761 (("%s")), thread_db_err_str (err));
1763 /* Cast assuming host == target. Joy. */
1764 /* Do proper sign extension for the target. */
1765 gdb_assert (exec_bfd);
1766 return (bfd_get_sign_extend_vma (exec_bfd) > 0
1767 ? (CORE_ADDR) (intptr_t) address
1768 : (CORE_ADDR) (uintptr_t) address);
1771 return beneath ()->get_thread_local_address (ptid, lm, offset);
1774 /* Implement the to_get_ada_task_ptid target method for this target. */
1777 thread_db_target::get_ada_task_ptid (long lwp, long thread)
1779 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1780 return ptid_t (inferior_ptid.pid (), lwp, 0);
1784 thread_db_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
1786 struct thread_db_info *info;
1788 if (ptid == minus_one_ptid)
1789 info = get_thread_db_info (inferior_ptid.pid ());
1791 info = get_thread_db_info (ptid.pid ());
1793 /* This workaround is only needed for child fork lwps stopped in a
1794 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1795 workaround can be disabled. */
1797 info->need_stale_parent_threads_check = 0;
1799 beneath ()->resume (ptid, step, signo);
1802 /* std::sort helper function for info_auto_load_libthread_db, sort the
1803 thread_db_info pointers primarily by their FILENAME and secondarily by their
1804 PID, both in ascending order. */
1807 info_auto_load_libthread_db_compare (const struct thread_db_info *a,
1808 const struct thread_db_info *b)
1812 retval = strcmp (a->filename, b->filename);
1816 return a->pid < b->pid;
1819 /* Implement 'info auto-load libthread-db'. */
1822 info_auto_load_libthread_db (const char *args, int from_tty)
1824 struct ui_out *uiout = current_uiout;
1825 const char *cs = args ? args : "";
1826 struct thread_db_info *info;
1827 unsigned unique_filenames;
1828 size_t max_filename_len, pids_len;
1831 cs = skip_spaces (cs);
1833 error (_("'info auto-load libthread-db' does not accept any parameters"));
1835 std::vector<struct thread_db_info *> array;
1836 for (info = thread_db_list; info; info = info->next)
1837 if (info->filename != NULL)
1838 array.push_back (info);
1840 /* Sort ARRAY by filenames and PIDs. */
1841 std::sort (array.begin (), array.end (),
1842 info_auto_load_libthread_db_compare);
1844 /* Calculate the number of unique filenames (rows) and the maximum string
1845 length of PIDs list for the unique filenames (columns). */
1847 unique_filenames = 0;
1848 max_filename_len = 0;
1850 for (i = 0; i < array.size (); i++)
1852 int pid = array[i]->pid;
1853 size_t this_pid_len;
1855 for (this_pid_len = 0; pid != 0; pid /= 10)
1858 if (i == 0 || strcmp (array[i - 1]->filename, array[i]->filename) != 0)
1861 max_filename_len = std::max (max_filename_len,
1862 strlen (array[i]->filename));
1865 pids_len -= strlen (", ");
1868 pids_len += this_pid_len + strlen (", ");
1871 pids_len -= strlen (", ");
1873 /* Table header shifted right by preceding "libthread-db: " would not match
1875 if (array.size () > 0 && args == auto_load_info_scripts_pattern_nl)
1879 ui_out_emit_table table_emitter (uiout, 2, unique_filenames,
1880 "LinuxThreadDbTable");
1882 uiout->table_header (max_filename_len, ui_left, "filename", "Filename");
1883 uiout->table_header (pids_len, ui_left, "PIDs", "Pids");
1884 uiout->table_body ();
1886 /* Note I is incremented inside the cycle, not at its end. */
1887 for (i = 0; i < array.size ();)
1889 ui_out_emit_tuple tuple_emitter (uiout, NULL);
1892 uiout->field_string ("filename", info->filename);
1895 while (i < array.size () && strcmp (info->filename,
1896 array[i]->filename) == 0)
1900 string_appendf (pids, "%u", array[i]->pid);
1904 uiout->field_string ("pids", pids.c_str ());
1911 uiout->message (_("No auto-loaded libthread-db.\n"));
1914 /* Implement 'maintenance check libthread-db'. */
1917 maintenance_check_libthread_db (const char *args, int from_tty)
1919 int inferior_pid = inferior_ptid.pid ();
1920 struct thread_db_info *info;
1922 if (inferior_pid == 0)
1923 error (_("No inferior running"));
1925 info = get_thread_db_info (inferior_pid);
1927 error (_("No libthread_db loaded"));
1929 check_thread_db (info, true);
1933 _initialize_thread_db (void)
1935 /* Defer loading of libthread_db.so until inferior is running.
1936 This allows gdb to load correct libthread_db for a given
1937 executable -- there could be multiple versions of glibc,
1938 and until there is a running inferior, we can't tell which
1939 libthread_db is the correct one to load. */
1941 libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
1943 add_setshow_optional_filename_cmd ("libthread-db-search-path",
1945 &libthread_db_search_path, _("\
1946 Set search path for libthread_db."), _("\
1947 Show the current search path or libthread_db."), _("\
1948 This path is used to search for libthread_db to be loaded into \
1950 Its value is a colon (':') separate list of directories to search.\n\
1951 Setting the search path to an empty list resets it to its default value."),
1952 set_libthread_db_search_path,
1954 &setlist, &showlist);
1956 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance,
1957 &libthread_db_debug, _("\
1958 Set libthread-db debugging."), _("\
1959 Show libthread-db debugging."), _("\
1960 When non-zero, libthread-db debugging is enabled."),
1962 show_libthread_db_debug,
1963 &setdebuglist, &showdebuglist);
1965 add_setshow_boolean_cmd ("libthread-db", class_support,
1966 &auto_load_thread_db, _("\
1967 Enable or disable auto-loading of inferior specific libthread_db."), _("\
1968 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
1969 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
1970 locations to load libthread_db compatible with the inferior.\n\
1971 Standard system libthread_db still gets loaded even with this option off.\n\
1972 This options has security implications for untrusted inferiors."),
1973 NULL, show_auto_load_thread_db,
1974 auto_load_set_cmdlist_get (),
1975 auto_load_show_cmdlist_get ());
1977 add_cmd ("libthread-db", class_info, info_auto_load_libthread_db,
1978 _("Print the list of loaded inferior specific libthread_db.\n\
1979 Usage: info auto-load libthread-db"),
1980 auto_load_info_cmdlist_get ());
1982 add_cmd ("libthread-db", class_maintenance,
1983 maintenance_check_libthread_db, _("\
1984 Run integrity checks on the current inferior's libthread_db."),
1985 &maintenancechecklist);
1987 add_setshow_boolean_cmd ("check-libthread-db",
1989 &check_thread_db_on_load, _("\
1990 Set whether to check libthread_db at load time."), _("\
1991 Show whether to check libthread_db at load time."), _("\
1992 If enabled GDB will run integrity checks on inferior specific libthread_db\n\
1993 as they are loaded."),
1996 &maintenance_set_cmdlist,
1997 &maintenance_show_cmdlist);
1999 /* Add ourselves to objfile event chain. */
2000 gdb::observers::new_objfile.attach (thread_db_new_objfile);
2002 /* Add ourselves to inferior_created event chain.
2003 This is needed to handle debugging statically linked programs where
2004 the new_objfile observer won't get called for libpthread. */
2005 gdb::observers::inferior_created.attach (thread_db_inferior_created);