12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052105310541055105610571058105910601061106210631064106510661067106810691070107110721073107410751076107710781079108010811082108310841085108610871088108910901091109210931094109510961097109810991100110111021103110411051106110711081109111011111112111311141115111611171118111911201121112211231124112511261127112811291130113111321133113411351136113711381139114011411142114311441145114611471148114911501151115211531154115511561157115811591160116111621163116411651166116711681169117011711172117311741175117611771178117911801181118211831184118511861187118811891190119111921193119411951196119711981199120012011202120312041205120612071208120912101211121212131214121512161217121812191220122112221223122412251226122712281229123012311232123312341235123612371238123912401241124212431244124512461247124812491250125112521253125412551256125712581259126012611262126312641265126612671268126912701271127212731274127512761277127812791280128112821283128412851286128712881289129012911292129312941295129612971298129913001301130213031304130513061307130813091310131113121313131413151316131713181319132013211322132313241325132613271328132913301331133213331334133513361337133813391340134113421343134413451346134713481349135013511352135313541355135613571358135913601361136213631364136513661367136813691370137113721373137413751376137713781379138013811382138313841385138613871388138913901391139213931394139513961397139813991400140114021403140414051406140714081409141014111412141314141415141614171418141914201421142214231424142514261427142814291430143114321433143414351436143714381439144014411442144314441445144614471448144914501451145214531454145514561457145814591460146114621463146414651466146714681469147014711472147314741475147614771478147914801481148214831484148514861487148814891490149114921493149414951496149714981499150015011502150315041505150615071508150915101511151215131514151515161517151815191520152115221523152415251526152715281529153015311532153315341535153615371538153915401541154215431544154515461547154815491550155115521553155415551556155715581559156015611562156315641565156615671568156915701571157215731574157515761577157815791580158115821583158415851586158715881589159015911592159315941595159615971598159916001601160216031604160516061607160816091610161116121613161416151616161716181619162016211622162316241625162616271628162916301631163216331634163516361637163816391640164116421643164416451646164716481649165016511652165316541655165616571658165916601661166216631664166516661667166816691670167116721673167416751676167716781679168016811682168316841685168616871688168916901691169216931694169516961697169816991700170117021703170417051706170717081709171017111712171317141715171617171718171917201721172217231724172517261727172817291730173117321733173417351736173717381739174017411742174317441745174617471748174917501751175217531754175517561757175817591760176117621763176417651766176717681769177017711772177317741775177617771778177917801781178217831784178517861787178817891790179117921793179417951796179717981799180018011802180318041805180618071808180918101811181218131814181518161817181818191820182118221823182418251826182718281829183018311832183318341835183618371838183918401841184218431844184518461847184818491850185118521853185418551856185718581859186018611862186318641865186618671868186918701871187218731874187518761877187818791880188118821883188418851886188718881889189018911892189318941895189618971898189919001901190219031904190519061907190819091910191119121913191419151916191719181919192019211922192319241925192619271928192919301931193219331934193519361937193819391940194119421943194419451946194719481949195019511952195319541955195619571958195919601961196219631964196519661967196819691970197119721973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012201320142015201620172018201920202021202220232024202520262027202820292030203120322033203420352036203720382039204020412042204320442045204620472048204920502051205220532054205520562057205820592060206120622063 |
- /* libthread_db assisted debugging support, generic parts.
- Copyright (C) 1999-2022 Free Software Foundation, Inc.
- This file is part of GDB.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include <dlfcn.h>
- #include "gdb_proc_service.h"
- #include "nat/gdb_thread_db.h"
- #include "gdbsupport/gdb_vecs.h"
- #include "bfd.h"
- #include "command.h"
- #include "gdbcmd.h"
- #include "gdbthread.h"
- #include "inferior.h"
- #include "infrun.h"
- #include "symfile.h"
- #include "objfiles.h"
- #include "target.h"
- #include "regcache.h"
- #include "solib.h"
- #include "solib-svr4.h"
- #include "gdbcore.h"
- #include "observable.h"
- #include "linux-nat.h"
- #include "nat/linux-procfs.h"
- #include "nat/linux-ptrace.h"
- #include "nat/linux-osdata.h"
- #include "auto-load.h"
- #include "cli/cli-utils.h"
- #include <signal.h>
- #include <ctype.h>
- #include "nat/linux-namespaces.h"
- #include <algorithm>
- #include "gdbsupport/pathstuff.h"
- #include "valprint.h"
- #include "cli/cli-style.h"
- /* GNU/Linux libthread_db support.
- libthread_db is a library, provided along with libpthread.so, which
- exposes the internals of the thread library to a debugger. It
- allows GDB to find existing threads, new threads as they are
- created, thread IDs (usually, the result of pthread_self), and
- thread-local variables.
- The libthread_db interface originates on Solaris, where it is both
- more powerful and more complicated. This implementation only works
- for NPTL, the glibc threading library. It assumes that each thread
- is permanently assigned to a single light-weight process (LWP). At
- some point it also supported the older LinuxThreads library, but it
- no longer does.
- libthread_db-specific information is stored in the "private" field
- of struct thread_info. When the field is NULL we do not yet have
- information about the new thread; this could be temporary (created,
- but the thread library's data structures do not reflect it yet)
- or permanent (created using clone instead of pthread_create).
- Process IDs managed by linux-thread-db.c match those used by
- linux-nat.c: a common PID for all processes, an LWP ID for each
- thread, and no TID. We save the TID in private. Keeping it out
- of the ptid_t prevents thread IDs changing when libpthread is
- loaded or unloaded. */
- static const target_info thread_db_target_info = {
- "multi-thread",
- N_("multi-threaded child process."),
- N_("Threads and pthreads support.")
- };
- class thread_db_target final : public target_ops
- {
- public:
- const target_info &info () const override
- { return thread_db_target_info; }
- strata stratum () const override { return thread_stratum; }
- void detach (inferior *, int) override;
- ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
- void resume (ptid_t, int, enum gdb_signal) override;
- void mourn_inferior () override;
- void follow_exec (inferior *, ptid_t, const char *) override;
- void update_thread_list () override;
- std::string pid_to_str (ptid_t) override;
- CORE_ADDR get_thread_local_address (ptid_t ptid,
- CORE_ADDR load_module_addr,
- CORE_ADDR offset) override;
- const char *extra_thread_info (struct thread_info *) override;
- ptid_t get_ada_task_ptid (long lwp, ULONGEST thread) override;
- thread_info *thread_handle_to_thread_info (const gdb_byte *thread_handle,
- int handle_len,
- inferior *inf) override;
- gdb::byte_vector thread_info_to_thread_handle (struct thread_info *) override;
- };
- static std::string libthread_db_search_path = LIBTHREAD_DB_SEARCH_PATH;
- /* Set to true if thread_db auto-loading is enabled
- by the "set auto-load libthread-db" command. */
- static bool auto_load_thread_db = true;
- /* Set to true if load-time libthread_db tests have been enabled
- by the "maintenance set check-libthread-db" command. */
- static bool check_thread_db_on_load = false;
- /* "show" command for the auto_load_thread_db configuration variable. */
- static void
- show_auto_load_thread_db (struct ui_file *file, int from_tty,
- struct cmd_list_element *c, const char *value)
- {
- gdb_printf (file, _("Auto-loading of inferior specific libthread_db "
- "is %s.\n"),
- value);
- }
- static void
- set_libthread_db_search_path (const char *ignored, int from_tty,
- struct cmd_list_element *c)
- {
- if (libthread_db_search_path.empty ())
- libthread_db_search_path = LIBTHREAD_DB_SEARCH_PATH;
- }
- /* If non-zero, print details of libthread_db processing. */
- static unsigned int libthread_db_debug;
- static void
- show_libthread_db_debug (struct ui_file *file, int from_tty,
- struct cmd_list_element *c, const char *value)
- {
- gdb_printf (file, _("libthread-db debugging is %s.\n"), value);
- }
- /* If we're running on GNU/Linux, we must explicitly attach to any new
- threads. */
- /* This module's target vector. */
- static thread_db_target the_thread_db_target;
- /* Non-zero if we have determined the signals used by the threads
- library. */
- static int thread_signals;
- struct thread_db_info
- {
- struct thread_db_info *next;
- /* The target this thread_db_info is bound to. */
- process_stratum_target *process_target;
- /* Process id this object refers to. */
- int pid;
- /* Handle from dlopen for libthread_db.so. */
- void *handle;
- /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
- HANDLE. It may be NULL for system library. */
- char *filename;
- /* Structure that identifies the child process for the
- <proc_service.h> interface. */
- struct ps_prochandle proc_handle;
- /* Connection to the libthread_db library. */
- td_thragent_t *thread_agent;
- /* True if we need to apply the workaround for glibc/BZ5983. When
- we catch a PTRACE_O_TRACEFORK, and go query the child's thread
- list, nptl_db returns the parent's threads in addition to the new
- (single) child thread. If this flag is set, we do extra work to
- be able to ignore such stale entries. */
- int need_stale_parent_threads_check;
- /* Pointers to the libthread_db functions. */
- td_init_ftype *td_init_p;
- td_ta_new_ftype *td_ta_new_p;
- td_ta_delete_ftype *td_ta_delete_p;
- td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p;
- td_ta_thr_iter_ftype *td_ta_thr_iter_p;
- td_thr_get_info_ftype *td_thr_get_info_p;
- td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p;
- td_thr_tlsbase_ftype *td_thr_tlsbase_p;
- };
- /* List of known processes using thread_db, and the required
- bookkeeping. */
- static thread_db_info *thread_db_list;
- static void thread_db_find_new_threads_1 (thread_info *stopped);
- static void thread_db_find_new_threads_2 (thread_info *stopped,
- bool until_no_new);
- static void check_thread_signals (void);
- static struct thread_info *record_thread
- (struct thread_db_info *info, struct thread_info *tp,
- ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p);
- /* Add the current inferior to the list of processes using libpthread.
- Return a pointer to the newly allocated object that was added to
- THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
- LIBTHREAD_DB_SO. */
- static struct thread_db_info *
- add_thread_db_info (void *handle)
- {
- struct thread_db_info *info = XCNEW (struct thread_db_info);
- info->process_target = current_inferior ()->process_target ();
- info->pid = inferior_ptid.pid ();
- info->handle = handle;
- /* The workaround works by reading from /proc/pid/status, so it is
- disabled for core files. */
- if (target_has_execution ())
- info->need_stale_parent_threads_check = 1;
- info->next = thread_db_list;
- thread_db_list = info;
- return info;
- }
- /* Return the thread_db_info object representing the bookkeeping
- related to process PID, if any; NULL otherwise. */
- static struct thread_db_info *
- get_thread_db_info (process_stratum_target *targ, int pid)
- {
- struct thread_db_info *info;
- for (info = thread_db_list; info; info = info->next)
- if (targ == info->process_target && pid == info->pid)
- return info;
- return NULL;
- }
- static const char *thread_db_err_str (td_err_e err);
- /* When PID has exited or has been detached, we no longer want to keep
- track of it as using libpthread. Call this function to discard
- thread_db related info related to PID. Note that this closes
- LIBTHREAD_DB_SO's dlopen'ed handle. */
- static void
- delete_thread_db_info (process_stratum_target *targ, int pid)
- {
- struct thread_db_info *info, *info_prev;
- info_prev = NULL;
- for (info = thread_db_list; info; info_prev = info, info = info->next)
- if (targ == info->process_target && pid == info->pid)
- break;
- if (info == NULL)
- return;
- if (info->thread_agent != NULL && info->td_ta_delete_p != NULL)
- {
- td_err_e err = info->td_ta_delete_p (info->thread_agent);
- if (err != TD_OK)
- warning (_("Cannot deregister process %d from libthread_db: %s"),
- pid, thread_db_err_str (err));
- info->thread_agent = NULL;
- }
- if (info->handle != NULL)
- dlclose (info->handle);
- xfree (info->filename);
- if (info_prev)
- info_prev->next = info->next;
- else
- thread_db_list = info->next;
- xfree (info);
- }
- /* Use "struct private_thread_info" to cache thread state. This is
- a substantial optimization. */
- struct thread_db_thread_info : public private_thread_info
- {
- /* Flag set when we see a TD_DEATH event for this thread. */
- bool dying = false;
- /* Cached thread state. */
- td_thrhandle_t th {};
- thread_t tid {};
- };
- static thread_db_thread_info *
- get_thread_db_thread_info (thread_info *thread)
- {
- return static_cast<thread_db_thread_info *> (thread->priv.get ());
- }
- static const char *
- thread_db_err_str (td_err_e err)
- {
- static char buf[64];
- switch (err)
- {
- case TD_OK:
- return "generic 'call succeeded'";
- case TD_ERR:
- return "generic error";
- case TD_NOTHR:
- return "no thread to satisfy query";
- case TD_NOSV:
- return "no sync handle to satisfy query";
- case TD_NOLWP:
- return "no LWP to satisfy query";
- case TD_BADPH:
- return "invalid process handle";
- case TD_BADTH:
- return "invalid thread handle";
- case TD_BADSH:
- return "invalid synchronization handle";
- case TD_BADTA:
- return "invalid thread agent";
- case TD_BADKEY:
- return "invalid key";
- case TD_NOMSG:
- return "no event message for getmsg";
- case TD_NOFPREGS:
- return "FPU register set not available";
- case TD_NOLIBTHREAD:
- return "application not linked with libthread";
- case TD_NOEVENT:
- return "requested event is not supported";
- case TD_NOCAPAB:
- return "capability not available";
- case TD_DBERR:
- return "debugger service failed";
- case TD_NOAPLIC:
- return "operation not applicable to";
- case TD_NOTSD:
- return "no thread-specific data for this thread";
- case TD_MALLOC:
- return "malloc failed";
- case TD_PARTIALREG:
- return "only part of register set was written/read";
- case TD_NOXREGS:
- return "X register set not available for this thread";
- #ifdef THREAD_DB_HAS_TD_NOTALLOC
- case TD_NOTALLOC:
- return "thread has not yet allocated TLS for given module";
- #endif
- #ifdef THREAD_DB_HAS_TD_VERSION
- case TD_VERSION:
- return "versions of libpthread and libthread_db do not match";
- #endif
- #ifdef THREAD_DB_HAS_TD_NOTLS
- case TD_NOTLS:
- return "there is no TLS segment in the given module";
- #endif
- default:
- snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
- return buf;
- }
- }
- /* Fetch the user-level thread id of PTID. STOPPED is a stopped
- thread that we can use to access memory. */
- static struct thread_info *
- thread_from_lwp (thread_info *stopped, ptid_t ptid)
- {
- td_thrhandle_t th;
- td_thrinfo_t ti;
- td_err_e err;
- struct thread_db_info *info;
- struct thread_info *tp;
- /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
- th.th_unique = 0;
- /* This ptid comes from linux-nat.c, which should always fill in the
- LWP. */
- gdb_assert (ptid.lwp () != 0);
- info = get_thread_db_info (stopped->inf->process_target (), ptid.pid ());
- /* Access an lwp we know is stopped. */
- info->proc_handle.thread = stopped;
- err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid.lwp (),
- &th);
- if (err != TD_OK)
- error (_("Cannot find user-level thread for LWP %ld: %s"),
- ptid.lwp (), thread_db_err_str (err));
- err = info->td_thr_get_info_p (&th, &ti);
- if (err != TD_OK)
- error (_("thread_get_info_callback: cannot get thread info: %s"),
- thread_db_err_str (err));
- /* Fill the cache. */
- tp = find_thread_ptid (stopped->inf->process_target (), ptid);
- return record_thread (info, tp, ptid, &th, &ti);
- }
- /* See linux-nat.h. */
- int
- thread_db_notice_clone (ptid_t parent, ptid_t child)
- {
- struct thread_db_info *info;
- info = get_thread_db_info (linux_target, child.pid ());
- if (info == NULL)
- return 0;
- thread_info *stopped = find_thread_ptid (linux_target, parent);
- thread_from_lwp (stopped, child);
- /* If we do not know about the main thread's pthread info yet, this
- would be a good time to find it. */
- thread_from_lwp (stopped, parent);
- return 1;
- }
- static void *
- verbose_dlsym (void *handle, const char *name)
- {
- void *sym = dlsym (handle, name);
- if (sym == NULL)
- warning (_("Symbol \"%s\" not found in libthread_db: %s"),
- name, dlerror ());
- return sym;
- }
- /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
- return 1 if this version is lower (and not equal) to
- VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
- static int
- inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min)
- {
- struct bound_minimal_symbol version_msym;
- CORE_ADDR version_addr;
- int got, retval = 0;
- version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL);
- if (version_msym.minsym == NULL)
- return 0;
- version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym);
- gdb::unique_xmalloc_ptr<char> version
- = target_read_string (version_addr, 32, &got);
- if (version != nullptr
- && memchr (version.get (), 0, got) == version.get () + got - 1)
- {
- int major, minor;
- retval = (sscanf (version.get (), "%d.%d", &major, &minor) == 2
- && (major < ver_major_min
- || (major == ver_major_min && minor < ver_minor_min)));
- }
- return retval;
- }
- /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
- if appropriate.
- Return 1 if the caller should abort libthread_db initialization. Return 0
- otherwise. */
- static int
- thread_db_find_new_threads_silently (thread_info *stopped)
- {
- try
- {
- thread_db_find_new_threads_2 (stopped, true);
- }
- catch (const gdb_exception_error &except)
- {
- if (libthread_db_debug)
- exception_fprintf (gdb_stdlog, except,
- "Warning: thread_db_find_new_threads_silently: ");
- /* There is a bug fixed between nptl 2.6.1 and 2.7 by
- commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
- where calls to td_thr_get_info fail with TD_ERR for statically linked
- executables if td_thr_get_info is called before glibc has initialized
- itself.
-
- If the nptl bug is NOT present in the inferior and still thread_db
- reports an error return 1. It means the inferior has corrupted thread
- list and GDB should fall back only to LWPs.
- If the nptl bug is present in the inferior return 0 to silently ignore
- such errors, and let gdb enumerate threads again later. In such case
- GDB cannot properly display LWPs if the inferior thread list is
- corrupted. For core files it does not apply, no 'later enumeration'
- is possible. */
- if (!target_has_execution () || !inferior_has_bug ("nptl_version", 2, 7))
- {
- exception_fprintf (gdb_stderr, except,
- _("Warning: couldn't activate thread debugging "
- "using libthread_db: "));
- return 1;
- }
- }
- return 0;
- }
- /* Lookup a library in which given symbol resides.
- Note: this is looking in GDB process, not in the inferior.
- Returns library name, or NULL. */
- static const char *
- dladdr_to_soname (const void *addr)
- {
- Dl_info info;
- if (dladdr (addr, &info) != 0)
- return info.dli_fname;
- return NULL;
- }
- /* State for check_thread_db_callback. */
- struct check_thread_db_info
- {
- /* The libthread_db under test. */
- struct thread_db_info *info;
- /* True if progress should be logged. */
- bool log_progress;
- /* True if the callback was called. */
- bool threads_seen;
- /* Name of last libthread_db function called. */
- const char *last_call;
- /* Value returned by last libthread_db call. */
- td_err_e last_result;
- };
- static struct check_thread_db_info *tdb_testinfo;
- /* Callback for check_thread_db. */
- static int
- check_thread_db_callback (const td_thrhandle_t *th, void *arg)
- {
- gdb_assert (tdb_testinfo != NULL);
- tdb_testinfo->threads_seen = true;
- #define LOG(fmt, args...) \
- do \
- { \
- if (tdb_testinfo->log_progress) \
- { \
- debug_printf (fmt, ## args); \
- gdb_flush (gdb_stdlog); \
- } \
- } \
- while (0)
- #define CHECK_1(expr, args...) \
- do \
- { \
- if (!(expr)) \
- { \
- LOG (" ... FAIL!\n"); \
- error (args); \
- } \
- } \
- while (0)
- #define CHECK(expr) \
- CHECK_1 (expr, "(%s) == false", #expr)
- #define CALL_UNCHECKED(func, args...) \
- do \
- { \
- tdb_testinfo->last_call = #func; \
- tdb_testinfo->last_result \
- = tdb_testinfo->info->func ## _p (args); \
- } \
- while (0)
- #define CHECK_CALL() \
- CHECK_1 (tdb_testinfo->last_result == TD_OK, \
- _("%s failed: %s"), \
- tdb_testinfo->last_call, \
- thread_db_err_str (tdb_testinfo->last_result)) \
- #define CALL(func, args...) \
- do \
- { \
- CALL_UNCHECKED (func, args); \
- CHECK_CALL (); \
- } \
- while (0)
- LOG (" Got thread");
- /* Check td_ta_thr_iter passed consistent arguments. */
- CHECK (th != NULL);
- CHECK (arg == (void *) tdb_testinfo);
- CHECK (th->th_ta_p == tdb_testinfo->info->thread_agent);
- LOG (" %s", core_addr_to_string_nz ((CORE_ADDR) th->th_unique));
- /* Check td_thr_get_info. */
- td_thrinfo_t ti;
- CALL (td_thr_get_info, th, &ti);
- LOG (" => %d", ti.ti_lid);
- CHECK (ti.ti_ta_p == th->th_ta_p);
- CHECK (ti.ti_tid == (thread_t) th->th_unique);
- /* Check td_ta_map_lwp2thr. */
- td_thrhandle_t th2;
- memset (&th2, 23, sizeof (td_thrhandle_t));
- CALL_UNCHECKED (td_ta_map_lwp2thr, th->th_ta_p, ti.ti_lid, &th2);
- if (tdb_testinfo->last_result == TD_ERR && !target_has_execution ())
- {
- /* Some platforms require execution for td_ta_map_lwp2thr. */
- LOG (_("; can't map_lwp2thr"));
- }
- else
- {
- CHECK_CALL ();
- LOG (" => %s", core_addr_to_string_nz ((CORE_ADDR) th2.th_unique));
- CHECK (memcmp (th, &th2, sizeof (td_thrhandle_t)) == 0);
- }
- /* Attempt TLS access. Assuming errno is TLS, this calls
- thread_db_get_thread_local_address, which in turn calls
- td_thr_tls_get_addr for live inferiors or td_thr_tlsbase
- for core files. This test is skipped if the thread has
- not been recorded; proceeding in that case would result
- in the test having the side-effect of noticing threads
- which seems wrong.
- Note that in glibc's libthread_db td_thr_tls_get_addr is
- a thin wrapper around td_thr_tlsbase; this check always
- hits the bulk of the code.
- Note also that we don't actually check any libthread_db
- calls are made, we just assume they were; future changes
- to how GDB accesses TLS could result in this passing
- without exercising the calls it's supposed to. */
- ptid_t ptid = ptid_t (tdb_testinfo->info->pid, ti.ti_lid);
- thread_info *thread_info = find_thread_ptid (linux_target, ptid);
- if (thread_info != NULL && thread_info->priv != NULL)
- {
- LOG ("; errno");
- scoped_restore_current_thread restore_current_thread;
- switch_to_thread (thread_info);
- expression_up expr = parse_expression ("(int) errno");
- struct value *val = evaluate_expression (expr.get ());
- if (tdb_testinfo->log_progress)
- {
- struct value_print_options opts;
- get_user_print_options (&opts);
- LOG (" = ");
- value_print (val, gdb_stdlog, &opts);
- }
- }
- LOG (" ... OK\n");
- #undef LOG
- #undef CHECK_1
- #undef CHECK
- #undef CALL_UNCHECKED
- #undef CHECK_CALL
- #undef CALL
- return 0;
- }
- /* Run integrity checks on the dlopen()ed libthread_db described by
- INFO. Returns true on success, displays a warning and returns
- false on failure. Logs progress messages to gdb_stdlog during
- the test if LOG_PROGRESS is true. */
- static bool
- check_thread_db (struct thread_db_info *info, bool log_progress)
- {
- bool test_passed = true;
- if (log_progress)
- debug_printf (_("Running libthread_db integrity checks:\n"));
- /* GDB avoids using td_ta_thr_iter wherever possible (see comment
- in try_thread_db_load_1 below) so in order to test it we may
- have to locate it ourselves. */
- td_ta_thr_iter_ftype *td_ta_thr_iter_p = info->td_ta_thr_iter_p;
- if (td_ta_thr_iter_p == NULL)
- {
- void *thr_iter = verbose_dlsym (info->handle, "td_ta_thr_iter");
- if (thr_iter == NULL)
- return 0;
- td_ta_thr_iter_p = (td_ta_thr_iter_ftype *) thr_iter;
- }
- /* Set up the test state we share with the callback. */
- gdb_assert (tdb_testinfo == NULL);
- struct check_thread_db_info tdb_testinfo_buf;
- tdb_testinfo = &tdb_testinfo_buf;
- memset (tdb_testinfo, 0, sizeof (struct check_thread_db_info));
- tdb_testinfo->info = info;
- tdb_testinfo->log_progress = log_progress;
- /* td_ta_thr_iter shouldn't be used on running processes. Note that
- it's possible the inferior will stop midway through modifying one
- of its thread lists, in which case the check will spuriously
- fail. */
- linux_stop_and_wait_all_lwps ();
- try
- {
- td_err_e err = td_ta_thr_iter_p (info->thread_agent,
- check_thread_db_callback,
- tdb_testinfo,
- TD_THR_ANY_STATE,
- TD_THR_LOWEST_PRIORITY,
- TD_SIGNO_MASK,
- TD_THR_ANY_USER_FLAGS);
- if (err != TD_OK)
- error (_("td_ta_thr_iter failed: %s"), thread_db_err_str (err));
- if (!tdb_testinfo->threads_seen)
- error (_("no threads seen"));
- }
- catch (const gdb_exception_error &except)
- {
- if (warning_pre_print)
- gdb_puts (warning_pre_print, gdb_stderr);
- exception_fprintf (gdb_stderr, except,
- _("libthread_db integrity checks failed: "));
- test_passed = false;
- }
- if (test_passed && log_progress)
- debug_printf (_("libthread_db integrity checks passed.\n"));
- tdb_testinfo = NULL;
- linux_unstop_all_lwps ();
- return test_passed;
- }
- /* Predicate which tests whether objfile OBJ refers to the library
- containing pthread related symbols. Historically, this library has
- been named in such a way that looking for "libpthread" in the name
- was sufficient to identify it. As of glibc-2.34, the C library
- (libc) contains the thread library symbols. Therefore we check
- that the name matches a possible thread library, but we also check
- that it contains at least one of the symbols (pthread_create) that
- we'd expect to find in the thread library. */
- static bool
- libpthread_objfile_p (objfile *obj)
- {
- return (libpthread_name_p (objfile_name (obj))
- && lookup_minimal_symbol ("pthread_create",
- NULL,
- obj).minsym != NULL);
- }
- /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
- Return true on success.
- Failure could happen if libthread_db does not have symbols we expect,
- or when it refuses to work with the current inferior (e.g. due to
- version mismatch between libthread_db and libpthread). */
- static bool
- try_thread_db_load_1 (struct thread_db_info *info)
- {
- td_err_e err;
- /* Initialize pointers to the dynamic library functions we will use.
- Essential functions first. */
- #define TDB_VERBOSE_DLSYM(info, func) \
- info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
- #define TDB_DLSYM(info, func) \
- info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
- #define CHK(a) \
- do \
- { \
- if ((a) == NULL) \
- return false; \
- } while (0)
- CHK (TDB_VERBOSE_DLSYM (info, td_init));
- err = info->td_init_p ();
- if (err != TD_OK)
- {
- warning (_("Cannot initialize libthread_db: %s"),
- thread_db_err_str (err));
- return false;
- }
- CHK (TDB_VERBOSE_DLSYM (info, td_ta_new));
- /* Initialize the structure that identifies the child process. */
- info->proc_handle.thread = inferior_thread ();
- /* Now attempt to open a connection to the thread library. */
- err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
- if (err != TD_OK)
- {
- if (libthread_db_debug)
- gdb_printf (gdb_stdlog, _("td_ta_new failed: %s\n"),
- thread_db_err_str (err));
- else
- switch (err)
- {
- case TD_NOLIBTHREAD:
- #ifdef THREAD_DB_HAS_TD_VERSION
- case TD_VERSION:
- #endif
- /* The errors above are not unexpected and silently ignored:
- they just mean we haven't found correct version of
- libthread_db yet. */
- break;
- default:
- warning (_("td_ta_new failed: %s"), thread_db_err_str (err));
- }
- return false;
- }
- /* These are essential. */
- CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr));
- CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info));
- /* These are not essential. */
- TDB_DLSYM (info, td_thr_tls_get_addr);
- TDB_DLSYM (info, td_thr_tlsbase);
- TDB_DLSYM (info, td_ta_delete);
- /* It's best to avoid td_ta_thr_iter if possible. That walks data
- structures in the inferior's address space that may be corrupted,
- or, if the target is running, may change while we walk them. If
- there's execution (and /proc is mounted), then we're already
- attached to all LWPs. Use thread_from_lwp, which uses
- td_ta_map_lwp2thr instead, which does not walk the thread list.
- td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
- currently on core targets, as it uses ptrace directly. */
- if (target_has_execution ()
- && linux_proc_task_list_dir_exists (inferior_ptid.pid ()))
- info->td_ta_thr_iter_p = NULL;
- else
- CHK (TDB_VERBOSE_DLSYM (info, td_ta_thr_iter));
- #undef TDB_VERBOSE_DLSYM
- #undef TDB_DLSYM
- #undef CHK
- /* Run integrity checks if requested. */
- if (check_thread_db_on_load)
- {
- if (!check_thread_db (info, libthread_db_debug))
- return false;
- }
- if (info->td_ta_thr_iter_p == NULL)
- {
- int pid = inferior_ptid.pid ();
- thread_info *curr_thread = inferior_thread ();
- linux_stop_and_wait_all_lwps ();
- for (const lwp_info *lp : all_lwps ())
- if (lp->ptid.pid () == pid)
- thread_from_lwp (curr_thread, lp->ptid);
- linux_unstop_all_lwps ();
- }
- else if (thread_db_find_new_threads_silently (inferior_thread ()) != 0)
- {
- /* Even if libthread_db initializes, if the thread list is
- corrupted, we'd not manage to list any threads. Better reject this
- thread_db, and fall back to at least listing LWPs. */
- return false;
- }
- gdb_printf (_("[Thread debugging using libthread_db enabled]\n"));
- if (!libthread_db_search_path.empty () || libthread_db_debug)
- {
- const char *library;
- library = dladdr_to_soname ((const void *) *info->td_ta_new_p);
- if (library == NULL)
- library = LIBTHREAD_DB_SO;
- gdb_printf (_("Using host libthread_db library \"%ps\".\n"),
- styled_string (file_name_style.style (), library));
- }
- /* The thread library was detected. Activate the thread_db target
- for this process. */
- current_inferior ()->push_target (&the_thread_db_target);
- return true;
- }
- /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
- relative, or just LIBTHREAD_DB. */
- static bool
- try_thread_db_load (const char *library, bool check_auto_load_safe)
- {
- void *handle;
- struct thread_db_info *info;
- if (libthread_db_debug)
- gdb_printf (gdb_stdlog,
- _("Trying host libthread_db library: %s.\n"),
- library);
- if (check_auto_load_safe)
- {
- if (access (library, R_OK) != 0)
- {
- /* Do not print warnings by file_is_auto_load_safe if the library does
- not exist at this place. */
- if (libthread_db_debug)
- gdb_printf (gdb_stdlog, _("open failed: %s.\n"),
- safe_strerror (errno));
- return false;
- }
- auto_load_debug_printf
- ("Loading libthread-db library \"%s\" from explicit directory.",
- library);
- if (!file_is_auto_load_safe (library))
- return false;
- }
- handle = dlopen (library, RTLD_NOW);
- if (handle == NULL)
- {
- if (libthread_db_debug)
- gdb_printf (gdb_stdlog, _("dlopen failed: %s.\n"), dlerror ());
- return false;
- }
- if (libthread_db_debug && strchr (library, '/') == NULL)
- {
- void *td_init;
- td_init = dlsym (handle, "td_init");
- if (td_init != NULL)
- {
- const char *const libpath = dladdr_to_soname (td_init);
- if (libpath != NULL)
- gdb_printf (gdb_stdlog, _("Host %s resolved to: %s.\n"),
- library, libpath);
- }
- }
- info = add_thread_db_info (handle);
- /* Do not save system library name, that one is always trusted. */
- if (strchr (library, '/') != NULL)
- info->filename = gdb_realpath (library).release ();
- try
- {
- if (try_thread_db_load_1 (info))
- return true;
- }
- catch (const gdb_exception_error &except)
- {
- if (libthread_db_debug)
- exception_fprintf (gdb_stdlog, except,
- "Warning: While trying to load libthread_db: ");
- }
- /* This library "refused" to work on current inferior. */
- delete_thread_db_info (current_inferior ()->process_target (),
- inferior_ptid.pid ());
- return false;
- }
- /* Subroutine of try_thread_db_load_from_pdir to simplify it.
- Try loading libthread_db in directory(OBJ)/SUBDIR.
- SUBDIR may be NULL. It may also be something like "../lib64".
- The result is true for success. */
- static bool
- try_thread_db_load_from_pdir_1 (struct objfile *obj, const char *subdir)
- {
- const char *obj_name = objfile_name (obj);
- if (obj_name[0] != '/')
- {
- warning (_("Expected absolute pathname for libpthread in the"
- " inferior, but got %ps."),
- styled_string (file_name_style.style (), obj_name));
- return false;
- }
- std::string path = obj_name;
- size_t cp = path.rfind ('/');
- /* This should at minimum hit the first character. */
- gdb_assert (cp != std::string::npos);
- path.resize (cp + 1);
- if (subdir != NULL)
- path = path + subdir + "/";
- path += LIBTHREAD_DB_SO;
- return try_thread_db_load (path.c_str (), true);
- }
- /* Handle $pdir in libthread-db-search-path.
- Look for libthread_db in directory(libpthread)/SUBDIR.
- SUBDIR may be NULL. It may also be something like "../lib64".
- The result is true for success. */
- static bool
- try_thread_db_load_from_pdir (const char *subdir)
- {
- if (!auto_load_thread_db)
- return false;
- for (objfile *obj : current_program_space->objfiles ())
- if (libpthread_objfile_p (obj))
- {
- if (try_thread_db_load_from_pdir_1 (obj, subdir))
- return true;
- /* We may have found the separate-debug-info version of
- libpthread, and it may live in a directory without a matching
- libthread_db. */
- if (obj->separate_debug_objfile_backlink != NULL)
- return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink,
- subdir);
- return false;
- }
- return false;
- }
- /* Handle $sdir in libthread-db-search-path.
- Look for libthread_db in the system dirs, or wherever a plain
- dlopen(file_without_path) will look.
- The result is true for success. */
- static bool
- try_thread_db_load_from_sdir (void)
- {
- return try_thread_db_load (LIBTHREAD_DB_SO, false);
- }
- /* Try to load libthread_db from directory DIR of length DIR_LEN.
- The result is true for success. */
- static bool
- try_thread_db_load_from_dir (const char *dir, size_t dir_len)
- {
- if (!auto_load_thread_db)
- return false;
- std::string path = std::string (dir, dir_len) + "/" + LIBTHREAD_DB_SO;
- return try_thread_db_load (path.c_str (), true);
- }
- /* Search libthread_db_search_path for libthread_db which "agrees"
- to work on current inferior.
- The result is true for success. */
- static bool
- thread_db_load_search (void)
- {
- bool rc = false;
- std::vector<gdb::unique_xmalloc_ptr<char>> dir_vec
- = dirnames_to_char_ptr_vec (libthread_db_search_path.c_str ());
- for (const gdb::unique_xmalloc_ptr<char> &this_dir_up : dir_vec)
- {
- const char *this_dir = this_dir_up.get ();
- const int pdir_len = sizeof ("$pdir") - 1;
- size_t this_dir_len;
- this_dir_len = strlen (this_dir);
- if (strncmp (this_dir, "$pdir", pdir_len) == 0
- && (this_dir[pdir_len] == '\0'
- || this_dir[pdir_len] == '/'))
- {
- const char *subdir = NULL;
- std::string subdir_holder;
- if (this_dir[pdir_len] == '/')
- {
- subdir_holder = std::string (this_dir + pdir_len + 1);
- subdir = subdir_holder.c_str ();
- }
- rc = try_thread_db_load_from_pdir (subdir);
- if (rc)
- break;
- }
- else if (strcmp (this_dir, "$sdir") == 0)
- {
- if (try_thread_db_load_from_sdir ())
- {
- rc = 1;
- break;
- }
- }
- else
- {
- if (try_thread_db_load_from_dir (this_dir, this_dir_len))
- {
- rc = 1;
- break;
- }
- }
- }
- if (libthread_db_debug)
- gdb_printf (gdb_stdlog,
- _("thread_db_load_search returning %d\n"), rc);
- return rc;
- }
- /* Return true if the inferior has a libpthread. */
- static bool
- has_libpthread (void)
- {
- for (objfile *obj : current_program_space->objfiles ())
- if (libpthread_objfile_p (obj))
- return true;
- return false;
- }
- /* Attempt to load and initialize libthread_db.
- Return 1 on success. */
- static bool
- thread_db_load (void)
- {
- inferior *inf = current_inferior ();
- /* When attaching / handling fork child, don't try loading libthread_db
- until we know about all shared libraries. */
- if (inf->in_initial_library_scan)
- return false;
- thread_db_info *info = get_thread_db_info (inf->process_target (),
- inferior_ptid.pid ());
- if (info != NULL)
- return true;
- /* Don't attempt to use thread_db on executables not running
- yet. */
- if (!target_has_registers ())
- return false;
- /* Don't attempt to use thread_db for remote targets. */
- if (!(target_can_run () || core_bfd))
- return false;
- if (thread_db_load_search ())
- return true;
- /* We couldn't find a libthread_db.
- If the inferior has a libpthread warn the user. */
- if (has_libpthread ())
- {
- warning (_("Unable to find libthread_db matching inferior's thread"
- " library, thread debugging will not be available."));
- return false;
- }
- /* Either this executable isn't using libpthread at all, or it is
- statically linked. Since we can't easily distinguish these two cases,
- no warning is issued. */
- return false;
- }
- static void
- check_thread_signals (void)
- {
- if (!thread_signals)
- {
- int i;
- for (i = 0; i < lin_thread_get_thread_signal_num (); i++)
- {
- int sig = lin_thread_get_thread_signal (i);
- signal_stop_update (gdb_signal_from_host (sig), 0);
- signal_print_update (gdb_signal_from_host (sig), 0);
- thread_signals = 1;
- }
- }
- }
- /* Check whether thread_db is usable. This function is called when
- an inferior is created (or otherwise acquired, e.g. attached to)
- and when new shared libraries are loaded into a running process. */
- static void
- check_for_thread_db (void)
- {
- /* Do nothing if we couldn't load libthread_db.so.1. */
- if (!thread_db_load ())
- return;
- }
- /* This function is called via the new_objfile observer. */
- static void
- thread_db_new_objfile (struct objfile *objfile)
- {
- /* This observer must always be called with inferior_ptid set
- correctly. */
- if (objfile != NULL
- /* libpthread with separate debug info has its debug info file already
- loaded (and notified without successful thread_db initialization)
- the time gdb::observers::new_objfile.notify is called for the library itself.
- Static executables have their separate debug info loaded already
- before the inferior has started. */
- && objfile->separate_debug_objfile_backlink == NULL
- /* Only check for thread_db if we loaded libpthread,
- or if this is the main symbol file.
- We need to check OBJF_MAINLINE to handle the case of debugging
- a statically linked executable AND the symbol file is specified AFTER
- the exec file is loaded (e.g., gdb -c core ; file foo).
- For dynamically linked executables, libpthread can be near the end
- of the list of shared libraries to load, and in an app of several
- thousand shared libraries, this can otherwise be painful. */
- && ((objfile->flags & OBJF_MAINLINE) != 0
- || libpthread_objfile_p (objfile)))
- check_for_thread_db ();
- }
- static void
- check_pid_namespace_match (inferior *inf)
- {
- /* Check is only relevant for local targets targets. */
- if (target_can_run ())
- {
- /* If the child is in a different PID namespace, its idea of its
- PID will differ from our idea of its PID. When we scan the
- child's thread list, we'll mistakenly think it has no threads
- since the thread PID fields won't match the PID we give to
- libthread_db. */
- if (!linux_ns_same (inf->pid, LINUX_NS_PID))
- {
- warning (_ ("Target and debugger are in different PID "
- "namespaces; thread lists and other data are "
- "likely unreliable. "
- "Connect to gdbserver inside the container."));
- }
- }
- }
- /* This function is called via the inferior_created observer.
- This handles the case of debugging statically linked executables. */
- static void
- thread_db_inferior_created (inferior *inf)
- {
- check_pid_namespace_match (inf);
- check_for_thread_db ();
- }
- /* Update the thread's state (what's displayed in "info threads"),
- from libthread_db thread state information. */
- static void
- update_thread_state (thread_db_thread_info *priv,
- const td_thrinfo_t *ti_p)
- {
- priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN
- || ti_p->ti_state == TD_THR_ZOMBIE);
- }
- /* Record a new thread in GDB's thread list. Creates the thread's
- private info. If TP is NULL or TP is marked as having exited,
- creates a new thread. Otherwise, uses TP. */
- static struct thread_info *
- record_thread (struct thread_db_info *info,
- struct thread_info *tp,
- ptid_t ptid, const td_thrhandle_t *th_p,
- const td_thrinfo_t *ti_p)
- {
- /* A thread ID of zero may mean the thread library has not
- initialized yet. Leave private == NULL until the thread library
- has initialized. */
- if (ti_p->ti_tid == 0)
- return tp;
- /* Construct the thread's private data. */
- thread_db_thread_info *priv = new thread_db_thread_info;
- priv->th = *th_p;
- priv->tid = ti_p->ti_tid;
- update_thread_state (priv, ti_p);
- /* Add the thread to GDB's thread list. If we already know about a
- thread with this PTID, but it's marked exited, then the kernel
- reused the tid of an old thread. */
- if (tp == NULL || tp->state == THREAD_EXITED)
- tp = add_thread_with_info (info->process_target, ptid, priv);
- else
- tp->priv.reset (priv);
- if (target_has_execution ())
- check_thread_signals ();
- return tp;
- }
- void
- thread_db_target::detach (inferior *inf, int from_tty)
- {
- delete_thread_db_info (inf->process_target (), inf->pid);
- beneath ()->detach (inf, from_tty);
- /* NOTE: From this point on, inferior_ptid is null_ptid. */
- /* Detach the thread_db target from this inferior. */
- inf->unpush_target (this);
- }
- ptid_t
- thread_db_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
- target_wait_flags options)
- {
- struct thread_db_info *info;
- process_stratum_target *beneath
- = as_process_stratum_target (this->beneath ());
- ptid = beneath->wait (ptid, ourstatus, options);
- switch (ourstatus->kind ())
- {
- case TARGET_WAITKIND_IGNORE:
- case TARGET_WAITKIND_EXITED:
- case TARGET_WAITKIND_THREAD_EXITED:
- case TARGET_WAITKIND_SIGNALLED:
- case TARGET_WAITKIND_EXECD:
- return ptid;
- }
- info = get_thread_db_info (beneath, ptid.pid ());
- /* If this process isn't using thread_db, we're done. */
- if (info == NULL)
- return ptid;
- /* Fill in the thread's user-level thread id and status. */
- thread_from_lwp (find_thread_ptid (beneath, ptid), ptid);
- return ptid;
- }
- void
- thread_db_target::mourn_inferior ()
- {
- process_stratum_target *target_beneath
- = as_process_stratum_target (this->beneath ());
- delete_thread_db_info (target_beneath, inferior_ptid.pid ());
- target_beneath->mourn_inferior ();
- /* Detach the thread_db target from this inferior. */
- current_inferior ()->unpush_target (this);
- }
- void
- thread_db_target::follow_exec (inferior *follow_inf, ptid_t ptid,
- const char *execd_pathname)
- {
- process_stratum_target *beneath
- = as_process_stratum_target (this->beneath ());
- delete_thread_db_info (beneath, ptid.pid ());
- current_inferior ()->unpush_target (this);
- beneath->follow_exec (follow_inf, ptid, execd_pathname);
- }
- struct callback_data
- {
- struct thread_db_info *info;
- int new_threads;
- };
- static int
- find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
- {
- td_thrinfo_t ti;
- td_err_e err;
- struct thread_info *tp;
- struct callback_data *cb_data = (struct callback_data *) data;
- struct thread_db_info *info = cb_data->info;
- err = info->td_thr_get_info_p (th_p, &ti);
- if (err != TD_OK)
- error (_("find_new_threads_callback: cannot get thread info: %s"),
- thread_db_err_str (err));
- if (ti.ti_lid == -1)
- {
- /* A thread with kernel thread ID -1 is either a thread that
- exited and was joined, or a thread that is being created but
- hasn't started yet, and that is reusing the tcb/stack of a
- thread that previously exited and was joined. (glibc marks
- terminated and joined threads with kernel thread ID -1. See
- glibc PR17707. */
- if (libthread_db_debug)
- gdb_printf (gdb_stdlog,
- "thread_db: skipping exited and "
- "joined thread (0x%lx)\n",
- (unsigned long) ti.ti_tid);
- return 0;
- }
- if (ti.ti_tid == 0)
- {
- /* A thread ID of zero means that this is the main thread, but
- glibc has not yet initialized thread-local storage and the
- pthread library. We do not know what the thread's TID will
- be yet. */
- /* In that case, we're not stopped in a fork syscall and don't
- need this glibc bug workaround. */
- info->need_stale_parent_threads_check = 0;
- return 0;
- }
- /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
- bit expensive, as it needs to open /proc/pid/status, so try to
- avoid doing the work if we know we don't have to. */
- if (info->need_stale_parent_threads_check)
- {
- int tgid = linux_proc_get_tgid (ti.ti_lid);
- if (tgid != -1 && tgid != info->pid)
- return 0;
- }
- ptid_t ptid (info->pid, ti.ti_lid);
- tp = find_thread_ptid (info->process_target, ptid);
- if (tp == NULL || tp->priv == NULL)
- record_thread (info, tp, ptid, th_p, &ti);
- return 0;
- }
- /* Helper for thread_db_find_new_threads_2.
- Returns number of new threads found. */
- static int
- find_new_threads_once (struct thread_db_info *info, int iteration,
- td_err_e *errp)
- {
- struct callback_data data;
- td_err_e err = TD_ERR;
- data.info = info;
- data.new_threads = 0;
- /* See comment in thread_db_update_thread_list. */
- gdb_assert (info->td_ta_thr_iter_p != NULL);
- try
- {
- /* Iterate over all user-space threads to discover new threads. */
- err = info->td_ta_thr_iter_p (info->thread_agent,
- find_new_threads_callback,
- &data,
- TD_THR_ANY_STATE,
- TD_THR_LOWEST_PRIORITY,
- TD_SIGNO_MASK,
- TD_THR_ANY_USER_FLAGS);
- }
- catch (const gdb_exception_error &except)
- {
- if (libthread_db_debug)
- {
- exception_fprintf (gdb_stdlog, except,
- "Warning: find_new_threads_once: ");
- }
- }
- if (libthread_db_debug)
- {
- gdb_printf (gdb_stdlog,
- _("Found %d new threads in iteration %d.\n"),
- data.new_threads, iteration);
- }
- if (errp != NULL)
- *errp = err;
- return data.new_threads;
- }
- /* Search for new threads, accessing memory through stopped thread
- PTID. If UNTIL_NO_NEW is true, repeat searching until several
- searches in a row do not discover any new threads. */
- static void
- thread_db_find_new_threads_2 (thread_info *stopped, bool until_no_new)
- {
- td_err_e err = TD_OK;
- struct thread_db_info *info;
- int i, loop;
- info = get_thread_db_info (stopped->inf->process_target (),
- stopped->ptid.pid ());
- /* Access an lwp we know is stopped. */
- info->proc_handle.thread = stopped;
- if (until_no_new)
- {
- /* Require 4 successive iterations which do not find any new threads.
- The 4 is a heuristic: there is an inherent race here, and I have
- seen that 2 iterations in a row are not always sufficient to
- "capture" all threads. */
- for (i = 0, loop = 0; loop < 4 && err == TD_OK; ++i, ++loop)
- if (find_new_threads_once (info, i, &err) != 0)
- {
- /* Found some new threads. Restart the loop from beginning. */
- loop = -1;
- }
- }
- else
- find_new_threads_once (info, 0, &err);
- if (err != TD_OK)
- error (_("Cannot find new threads: %s"), thread_db_err_str (err));
- }
- static void
- thread_db_find_new_threads_1 (thread_info *stopped)
- {
- thread_db_find_new_threads_2 (stopped, 0);
- }
- /* Implement the to_update_thread_list target method for this
- target. */
- void
- thread_db_target::update_thread_list ()
- {
- struct thread_db_info *info;
- prune_threads ();
- for (inferior *inf : all_inferiors ())
- {
- if (inf->pid == 0)
- continue;
- info = get_thread_db_info (inf->process_target (), inf->pid);
- if (info == NULL)
- continue;
- thread_info *thread = any_live_thread_of_inferior (inf);
- if (thread == NULL || thread->executing ())
- continue;
- /* It's best to avoid td_ta_thr_iter if possible. That walks
- data structures in the inferior's address space that may be
- corrupted, or, if the target is running, the list may change
- while we walk it. In the latter case, it's possible that a
- thread exits just at the exact time that causes GDB to get
- stuck in an infinite loop. To avoid pausing all threads
- whenever the core wants to refresh the thread list, we
- instead use thread_from_lwp immediately when we see an LWP
- stop. That uses thread_db entry points that do not walk
- libpthread's thread list, so should be safe, as well as more
- efficient. */
- if (thread->inf->has_execution ())
- continue;
- thread_db_find_new_threads_1 (thread);
- }
- /* Give the beneath target a chance to do extra processing. */
- this->beneath ()->update_thread_list ();
- }
- std::string
- thread_db_target::pid_to_str (ptid_t ptid)
- {
- thread_info *thread_info = find_thread_ptid (current_inferior (), ptid);
- if (thread_info != NULL && thread_info->priv != NULL)
- {
- thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
- return string_printf ("Thread 0x%lx (LWP %ld)",
- (unsigned long) priv->tid, ptid.lwp ());
- }
- return beneath ()->pid_to_str (ptid);
- }
- /* Return a string describing the state of the thread specified by
- INFO. */
- const char *
- thread_db_target::extra_thread_info (thread_info *info)
- {
- if (info->priv == NULL)
- return NULL;
- thread_db_thread_info *priv = get_thread_db_thread_info (info);
- if (priv->dying)
- return "Exiting";
- return NULL;
- }
- /* Return pointer to the thread_info struct which corresponds to
- THREAD_HANDLE (having length HANDLE_LEN). */
- thread_info *
- thread_db_target::thread_handle_to_thread_info (const gdb_byte *thread_handle,
- int handle_len,
- inferior *inf)
- {
- thread_t handle_tid;
- /* When debugging a 32-bit target from a 64-bit host, handle_len
- will be 4 and sizeof (handle_tid) will be 8. This requires
- a different cast than the more straightforward case where
- the sizes are the same.
- Use "--target_board unix/-m32" from a native x86_64 linux build
- to test the 32/64-bit case. */
- if (handle_len == 4 && sizeof (handle_tid) == 8)
- handle_tid = (thread_t) * (const uint32_t *) thread_handle;
- else if (handle_len == sizeof (handle_tid))
- handle_tid = * (const thread_t *) thread_handle;
- else
- error (_("Thread handle size mismatch: %d vs %zu (from libthread_db)"),
- handle_len, sizeof (handle_tid));
- for (thread_info *tp : inf->non_exited_threads ())
- {
- thread_db_thread_info *priv = get_thread_db_thread_info (tp);
- if (priv != NULL && handle_tid == priv->tid)
- return tp;
- }
- return NULL;
- }
- /* Return the thread handle associated the thread_info pointer TP. */
- gdb::byte_vector
- thread_db_target::thread_info_to_thread_handle (struct thread_info *tp)
- {
- thread_db_thread_info *priv = get_thread_db_thread_info (tp);
- if (priv == NULL)
- return gdb::byte_vector ();
- int handle_size = sizeof (priv->tid);
- gdb::byte_vector rv (handle_size);
- memcpy (rv.data (), &priv->tid, handle_size);
- return rv;
- }
- /* Get the address of the thread local variable in load module LM which
- is stored at OFFSET within the thread local storage for thread PTID. */
- CORE_ADDR
- thread_db_target::get_thread_local_address (ptid_t ptid,
- CORE_ADDR lm,
- CORE_ADDR offset)
- {
- struct thread_info *thread_info;
- process_stratum_target *beneath
- = as_process_stratum_target (this->beneath ());
- /* Find the matching thread. */
- thread_info = find_thread_ptid (beneath, ptid);
- /* We may not have discovered the thread yet. */
- if (thread_info != NULL && thread_info->priv == NULL)
- thread_info = thread_from_lwp (thread_info, ptid);
- if (thread_info != NULL && thread_info->priv != NULL)
- {
- td_err_e err;
- psaddr_t address;
- thread_db_info *info = get_thread_db_info (beneath, ptid.pid ());
- thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
- /* Finally, get the address of the variable. */
- if (lm != 0)
- {
- /* glibc doesn't provide the needed interface. */
- if (!info->td_thr_tls_get_addr_p)
- throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
- _("No TLS library support"));
- /* Note the cast through uintptr_t: this interface only works if
- a target address fits in a psaddr_t, which is a host pointer.
- So a 32-bit debugger can not access 64-bit TLS through this. */
- err = info->td_thr_tls_get_addr_p (&priv->th,
- (psaddr_t)(uintptr_t) lm,
- offset, &address);
- }
- else
- {
- /* If glibc doesn't provide the needed interface throw an error
- that LM is zero - normally cases it should not be. */
- if (!info->td_thr_tlsbase_p)
- throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
- _("TLS load module not found"));
- /* This code path handles the case of -static -pthread executables:
- https://sourceware.org/ml/libc-help/2014-03/msg00024.html
- For older GNU libc r_debug.r_map is NULL. For GNU libc after
- PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
- The constant number 1 depends on GNU __libc_setup_tls
- initialization of l_tls_modid to 1. */
- err = info->td_thr_tlsbase_p (&priv->th, 1, &address);
- address = (char *) address + offset;
- }
- #ifdef THREAD_DB_HAS_TD_NOTALLOC
- /* The memory hasn't been allocated, yet. */
- if (err == TD_NOTALLOC)
- /* Now, if libthread_db provided the initialization image's
- address, we *could* try to build a non-lvalue value from
- the initialization image. */
- throw_error (TLS_NOT_ALLOCATED_YET_ERROR,
- _("TLS not allocated yet"));
- #endif
- /* Something else went wrong. */
- if (err != TD_OK)
- throw_error (TLS_GENERIC_ERROR,
- (("%s")), thread_db_err_str (err));
- /* Cast assuming host == target. Joy. */
- /* Do proper sign extension for the target. */
- gdb_assert (current_program_space->exec_bfd ());
- return (bfd_get_sign_extend_vma (current_program_space->exec_bfd ()) > 0
- ? (CORE_ADDR) (intptr_t) address
- : (CORE_ADDR) (uintptr_t) address);
- }
- return beneath->get_thread_local_address (ptid, lm, offset);
- }
- /* Implement the to_get_ada_task_ptid target method for this target. */
- ptid_t
- thread_db_target::get_ada_task_ptid (long lwp, ULONGEST thread)
- {
- /* NPTL uses a 1:1 model, so the LWP id suffices. */
- return ptid_t (inferior_ptid.pid (), lwp);
- }
- void
- thread_db_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
- {
- process_stratum_target *beneath
- = as_process_stratum_target (this->beneath ());
- thread_db_info *info
- = get_thread_db_info (beneath, (ptid == minus_one_ptid
- ? inferior_ptid.pid ()
- : ptid.pid ()));
- /* This workaround is only needed for child fork lwps stopped in a
- PTRACE_O_TRACEFORK event. When the inferior is resumed, the
- workaround can be disabled. */
- if (info)
- info->need_stale_parent_threads_check = 0;
- beneath->resume (ptid, step, signo);
- }
- /* std::sort helper function for info_auto_load_libthread_db, sort the
- thread_db_info pointers primarily by their FILENAME and secondarily by their
- PID, both in ascending order. */
- static bool
- info_auto_load_libthread_db_compare (const struct thread_db_info *a,
- const struct thread_db_info *b)
- {
- int retval;
- retval = strcmp (a->filename, b->filename);
- if (retval)
- return retval < 0;
- return a->pid < b->pid;
- }
- /* Implement 'info auto-load libthread-db'. */
- static void
- info_auto_load_libthread_db (const char *args, int from_tty)
- {
- struct ui_out *uiout = current_uiout;
- const char *cs = args ? args : "";
- struct thread_db_info *info;
- unsigned unique_filenames;
- size_t max_filename_len, pids_len;
- int i;
- cs = skip_spaces (cs);
- if (*cs)
- error (_("'info auto-load libthread-db' does not accept any parameters"));
- std::vector<struct thread_db_info *> array;
- for (info = thread_db_list; info; info = info->next)
- if (info->filename != NULL)
- array.push_back (info);
- /* Sort ARRAY by filenames and PIDs. */
- std::sort (array.begin (), array.end (),
- info_auto_load_libthread_db_compare);
- /* Calculate the number of unique filenames (rows) and the maximum string
- length of PIDs list for the unique filenames (columns). */
- unique_filenames = 0;
- max_filename_len = 0;
- pids_len = 0;
- for (i = 0; i < array.size (); i++)
- {
- int pid = array[i]->pid;
- size_t this_pid_len;
- for (this_pid_len = 0; pid != 0; pid /= 10)
- this_pid_len++;
- if (i == 0 || strcmp (array[i - 1]->filename, array[i]->filename) != 0)
- {
- unique_filenames++;
- max_filename_len = std::max (max_filename_len,
- strlen (array[i]->filename));
- if (i > 0)
- pids_len -= strlen (", ");
- pids_len = 0;
- }
- pids_len += this_pid_len + strlen (", ");
- }
- if (i)
- pids_len -= strlen (", ");
- /* Table header shifted right by preceding "libthread-db: " would not match
- its columns. */
- if (array.size () > 0 && args == auto_load_info_scripts_pattern_nl)
- uiout->text ("\n");
- {
- ui_out_emit_table table_emitter (uiout, 2, unique_filenames,
- "LinuxThreadDbTable");
- uiout->table_header (max_filename_len, ui_left, "filename", "Filename");
- uiout->table_header (pids_len, ui_left, "PIDs", "Pids");
- uiout->table_body ();
- /* Note I is incremented inside the cycle, not at its end. */
- for (i = 0; i < array.size ();)
- {
- ui_out_emit_tuple tuple_emitter (uiout, NULL);
- info = array[i];
- uiout->field_string ("filename", info->filename,
- file_name_style.style ());
- std::string pids;
- while (i < array.size () && strcmp (info->filename,
- array[i]->filename) == 0)
- {
- if (!pids.empty ())
- pids += ", ";
- string_appendf (pids, "%u", array[i]->pid);
- i++;
- }
- uiout->field_string ("pids", pids);
- uiout->text ("\n");
- }
- }
- if (array.empty ())
- uiout->message (_("No auto-loaded libthread-db.\n"));
- }
- /* Implement 'maintenance check libthread-db'. */
- static void
- maintenance_check_libthread_db (const char *args, int from_tty)
- {
- int inferior_pid = inferior_ptid.pid ();
- struct thread_db_info *info;
- if (inferior_pid == 0)
- error (_("No inferior running"));
- info = get_thread_db_info (current_inferior ()->process_target (),
- inferior_pid);
- if (info == NULL)
- error (_("No libthread_db loaded"));
- check_thread_db (info, true);
- }
- void _initialize_thread_db ();
- void
- _initialize_thread_db ()
- {
- /* Defer loading of libthread_db.so until inferior is running.
- This allows gdb to load correct libthread_db for a given
- executable -- there could be multiple versions of glibc,
- and until there is a running inferior, we can't tell which
- libthread_db is the correct one to load. */
- add_setshow_optional_filename_cmd ("libthread-db-search-path",
- class_support,
- &libthread_db_search_path, _("\
- Set search path for libthread_db."), _("\
- Show the current search path or libthread_db."), _("\
- This path is used to search for libthread_db to be loaded into \
- gdb itself.\n\
- Its value is a colon (':') separate list of directories to search.\n\
- Setting the search path to an empty list resets it to its default value."),
- set_libthread_db_search_path,
- NULL,
- &setlist, &showlist);
- add_setshow_zuinteger_cmd ("libthread-db", class_maintenance,
- &libthread_db_debug, _("\
- Set libthread-db debugging."), _("\
- Show libthread-db debugging."), _("\
- When non-zero, libthread-db debugging is enabled."),
- NULL,
- show_libthread_db_debug,
- &setdebuglist, &showdebuglist);
- add_setshow_boolean_cmd ("libthread-db", class_support,
- &auto_load_thread_db, _("\
- Enable or disable auto-loading of inferior specific libthread_db."), _("\
- Show whether auto-loading inferior specific libthread_db is enabled."), _("\
- If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
- locations to load libthread_db compatible with the inferior.\n\
- Standard system libthread_db still gets loaded even with this option off.\n\
- This option has security implications for untrusted inferiors."),
- NULL, show_auto_load_thread_db,
- auto_load_set_cmdlist_get (),
- auto_load_show_cmdlist_get ());
- add_cmd ("libthread-db", class_info, info_auto_load_libthread_db,
- _("Print the list of loaded inferior specific libthread_db.\n\
- Usage: info auto-load libthread-db"),
- auto_load_info_cmdlist_get ());
- add_cmd ("libthread-db", class_maintenance,
- maintenance_check_libthread_db, _("\
- Run integrity checks on the current inferior's libthread_db."),
- &maintenancechecklist);
- add_setshow_boolean_cmd ("check-libthread-db",
- class_maintenance,
- &check_thread_db_on_load, _("\
- Set whether to check libthread_db at load time."), _("\
- Show whether to check libthread_db at load time."), _("\
- If enabled GDB will run integrity checks on inferior specific libthread_db\n\
- as they are loaded."),
- NULL,
- NULL,
- &maintenance_set_cmdlist,
- &maintenance_show_cmdlist);
- /* Add ourselves to objfile event chain. */
- gdb::observers::new_objfile.attach (thread_db_new_objfile, "linux-thread-db");
- /* Add ourselves to inferior_created event chain.
- This is needed to handle debugging statically linked programs where
- the new_objfile observer won't get called for libpthread. */
- gdb::observers::inferior_created.attach (thread_db_inferior_created,
- "linux-thread-db");
- }
|