X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Flinux-thread-db.c;h=6d981357cf804f7c366326cc0f130cbfe0fa7d58;hb=14278e1fdbe045df184d6dd546ff6a1e9e3c3797;hp=f43efc74c4898943a36530f254222625012a6981;hpb=05386e9ec7208d79280caffeff0b01ebea63875c;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c index f43efc74c4..6d981357cf 100644 --- a/gdb/linux-thread-db.c +++ b/gdb/linux-thread-db.c @@ -1,7 +1,6 @@ /* libthread_db assisted debugging support, generic parts. - Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, - 2010, 2011 Free Software Foundation, Inc. + Copyright (C) 1999-2017 Free Software Foundation, Inc. This file is part of GDB. @@ -19,18 +18,16 @@ along with this program. If not, see . */ #include "defs.h" - -#include "gdb_assert.h" #include #include "gdb_proc_service.h" -#include "gdb_thread_db.h" - +#include "nat/gdb_thread_db.h" +#include "gdb_vecs.h" #include "bfd.h" #include "command.h" -#include "exceptions.h" #include "gdbcmd.h" #include "gdbthread.h" #include "inferior.h" +#include "infrun.h" #include "symfile.h" #include "objfiles.h" #include "target.h" @@ -40,12 +37,15 @@ #include "gdbcore.h" #include "observer.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 - -#ifdef HAVE_GNU_LIBC_VERSION_H -#include -#endif +#include +#include "nat/linux-namespaces.h" +#include /* GNU/Linux libthread_db support. @@ -55,11 +55,12 @@ 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 LinuxThreads and NPTL, the two glibc threading - libraries. It assumes that each thread is permanently assigned - to a single light-weight process (LWP). + 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 @@ -75,6 +76,21 @@ static char *libthread_db_search_path; +/* Set to non-zero if thread_db auto-loading is enabled + by the "set auto-load libthread-db" command. */ +static int auto_load_thread_db = 1; + +/* "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) +{ + fprintf_filtered (file, _("Auto-loading of inferior specific libthread_db " + "is %s.\n"), + value); +} + static void set_libthread_db_search_path (char *ignored, int from_tty, struct cmd_list_element *c) @@ -88,7 +104,7 @@ set_libthread_db_search_path (char *ignored, int from_tty, /* If non-zero, print details of libthread_db processing. */ -static int libthread_db_debug; +static unsigned int libthread_db_debug; static void show_libthread_db_debug (struct ui_file *file, int from_tty, @@ -119,6 +135,10 @@ struct thread_db_info /* 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 interface. */ struct ps_prochandle proc_handle; @@ -133,50 +153,15 @@ struct thread_db_info be able to ignore such stale entries. */ int need_stale_parent_threads_check; - /* Location of the thread creation event breakpoint. The code at - this location in the child process will be called by the pthread - library whenever a new thread is created. By setting a special - breakpoint at this location, GDB can detect when a new thread is - created. We obtain this location via the td_ta_event_addr - call. */ - CORE_ADDR td_create_bp_addr; - - /* Location of the thread death event breakpoint. */ - CORE_ADDR td_death_bp_addr; - /* Pointers to the libthread_db functions. */ - td_err_e (*td_init_p) (void); - - td_err_e (*td_ta_new_p) (struct ps_prochandle * ps, - td_thragent_t **ta); - td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt, - td_thrhandle_t *__th); - td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta, - lwpid_t lwpid, td_thrhandle_t *th); - td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta, - td_thr_iter_f *callback, void *cbdata_p, - td_thr_state_e state, int ti_pri, - sigset_t *ti_sigmask_p, - unsigned int ti_user_flags); - td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta, - td_event_e event, td_notify_t *ptr); - td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta, - td_thr_events_t *event); - td_err_e (*td_ta_clear_event_p) (const td_thragent_t *ta, - td_thr_events_t *event); - td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta, - td_event_msg_t *msg); - - td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th); - td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th, - td_thrinfo_t *infop); - td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th, - int event); - - td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th, - psaddr_t map_address, - size_t offset, psaddr_t *address); + td_init_ftype *td_init_p; + td_ta_new_ftype *td_ta_new_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 @@ -186,6 +171,12 @@ struct thread_db_info *thread_db_list; static void thread_db_find_new_threads_1 (ptid_t ptid); static void thread_db_find_new_threads_2 (ptid_t ptid, int 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 @@ -194,9 +185,8 @@ static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new); static struct thread_db_info * add_thread_db_info (void *handle) { - struct thread_db_info *info; + struct thread_db_info *info = XCNEW (struct thread_db_info); - info = xcalloc (1, sizeof (*info)); info->pid = ptid_get_pid (inferior_ptid); info->handle = handle; @@ -248,6 +238,8 @@ delete_thread_db_info (int pid) if (info->handle != NULL) dlclose (info->handle); + xfree (info->filename); + if (info_prev) info_prev->next = info->next; else @@ -256,12 +248,6 @@ delete_thread_db_info (int pid) xfree (info); } -/* Prototypes for local functions. */ -static int attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, - const td_thrinfo_t *ti_p); -static void detach_thread (ptid_t ptid); - - /* Use "struct private_thread_info" to cache thread state. This is a substantial optimization. */ @@ -276,7 +262,7 @@ struct private_thread_info }; -static char * +static const char * thread_db_err_str (td_err_e err) { static char buf[64]; @@ -342,169 +328,63 @@ thread_db_err_str (td_err_e err) return buf; } } - -/* Return 1 if any threads have been registered. There may be none if - the threading library is not fully initialized yet. */ - -static int -have_threads_callback (struct thread_info *thread, void *args) -{ - int pid = * (int *) args; - - if (ptid_get_pid (thread->ptid) != pid) - return 0; - - return thread->private != NULL; -} - -static int -have_threads (ptid_t ptid) -{ - int pid = ptid_get_pid (ptid); - - return iterate_over_threads (have_threads_callback, &pid) != NULL; -} - -struct thread_get_info_inout -{ - struct thread_info *thread_info; - struct thread_db_info *thread_db_info; -}; - -/* A callback function for td_ta_thr_iter, which we use to map all - threads to LWPs. - - THP is a handle to the current thread; if INFOP is not NULL, the - struct thread_info associated with this thread is returned in - *INFOP. - - If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise, - zero is returned to indicate success. */ - -static int -thread_get_info_callback (const td_thrhandle_t *thp, void *argp) -{ - td_thrinfo_t ti; - td_err_e err; - ptid_t thread_ptid; - struct thread_get_info_inout *inout; - struct thread_db_info *info; - - inout = argp; - info = inout->thread_db_info; - - err = info->td_thr_get_info_p (thp, &ti); - if (err != TD_OK) - error (_("thread_get_info_callback: cannot get thread info: %s"), - thread_db_err_str (err)); - /* Fill the cache. */ - thread_ptid = ptid_build (info->pid, ti.ti_lid, 0); - inout->thread_info = find_thread_ptid (thread_ptid); - - /* In the case of a zombie thread, don't continue. We don't want to - attach to it thinking it is a new thread. */ - if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE) - return TD_THR_ZOMBIE; - - if (inout->thread_info == NULL) - { - /* New thread. Attach to it now (why wait?). */ - if (!have_threads (thread_ptid)) - thread_db_find_new_threads_1 (thread_ptid); - else - attach_thread (thread_ptid, thp, &ti); - inout->thread_info = find_thread_ptid (thread_ptid); - gdb_assert (inout->thread_info != NULL); - } - - return 0; -} - -/* Convert between user-level thread ids and LWP ids. */ +/* Fetch the user-level thread id of PTID. */ -static ptid_t +static struct thread_info * thread_from_lwp (ptid_t ptid) { td_thrhandle_t th; + td_thrinfo_t ti; td_err_e err; struct thread_db_info *info; - struct thread_get_info_inout io = {0}; + 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 (GET_LWP (ptid) != 0); + gdb_assert (ptid_get_lwp (ptid) != 0); - info = get_thread_db_info (GET_PID (ptid)); + info = get_thread_db_info (ptid_get_pid (ptid)); /* Access an lwp we know is stopped. */ info->proc_handle.ptid = ptid; - err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th); + err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid_get_lwp (ptid), + &th); if (err != TD_OK) error (_("Cannot find user-level thread for LWP %ld: %s"), - GET_LWP (ptid), thread_db_err_str (err)); - - /* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the - event thread has already died. If another gdb interface has called - thread_alive() previously, the thread won't be found on the thread list - anymore. In that case, we don't want to process this ptid anymore - to avoid the possibility of later treating it as a newly - discovered thread id that we should add to the list. Thus, - we return a -1 ptid which is also how the thread list marks a - dead thread. */ - io.thread_db_info = info; - io.thread_info = NULL; - if (thread_get_info_callback (&th, &io) == TD_THR_ZOMBIE - && io.thread_info == NULL) - return minus_one_ptid; - - gdb_assert (ptid_get_tid (ptid) == 0); - return ptid; + ptid_get_lwp (ptid), 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 (ptid); + return record_thread (info, tp, ptid, &th, &ti); } -/* Attach to lwp PTID, doing whatever else is required to have this - LWP under the debugger's control --- e.g., enabling event - reporting. Returns true on success. */ +/* See linux-nat.h. */ + int -thread_db_attach_lwp (ptid_t ptid) +thread_db_notice_clone (ptid_t parent, ptid_t child) { - td_thrhandle_t th; - td_thrinfo_t ti; - td_err_e err; struct thread_db_info *info; - info = get_thread_db_info (GET_PID (ptid)); + info = get_thread_db_info (ptid_get_pid (child)); if (info == NULL) return 0; - /* This ptid comes from linux-nat.c, which should always fill in the - LWP. */ - gdb_assert (GET_LWP (ptid) != 0); - - /* Access an lwp we know is stopped. */ - info->proc_handle.ptid = ptid; - - /* If we have only looked at the first thread before libpthread was - initialized, we may not know its thread ID yet. Make sure we do - before we add another thread to the list. */ - if (!have_threads (ptid)) - thread_db_find_new_threads_1 (ptid); - - err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th); - if (err != TD_OK) - /* Cannot find user-level thread. */ - return 0; - - err = info->td_thr_get_info_p (&th, &ti); - if (err != TD_OK) - { - warning (_("Cannot get thread info: %s"), thread_db_err_str (err)); - return 0; - } + thread_from_lwp (child); - attach_thread (ptid, &th, &ti); + /* If we do not know about the main thread yet, this would be a good + time to find it. */ + thread_from_lwp (parent); return 1; } @@ -518,121 +398,85 @@ verbose_dlsym (void *handle, const char *name) return sym; } -static td_err_e -enable_thread_event (int event, CORE_ADDR *bp) -{ - td_notify_t notify; - td_err_e err; - struct thread_db_info *info; - - info = get_thread_db_info (GET_PID (inferior_ptid)); +/* 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. */ - /* Access an lwp we know is stopped. */ - info->proc_handle.ptid = inferior_ptid; - - /* Get the breakpoint address for thread EVENT. */ - err = info->td_ta_event_addr_p (info->thread_agent, event, ¬ify); - if (err != TD_OK) - return err; - - /* Set up the breakpoint. */ - gdb_assert (exec_bfd); - (*bp) = (gdbarch_convert_from_func_ptr_addr - (target_gdbarch, - /* Do proper sign extension for the target. */ - (bfd_get_sign_extend_vma (exec_bfd) > 0 - ? (CORE_ADDR) (intptr_t) notify.u.bptaddr - : (CORE_ADDR) (uintptr_t) notify.u.bptaddr), - ¤t_target)); - create_thread_event_breakpoint (target_gdbarch, *bp); - - return TD_OK; -} - -static void -enable_thread_event_reporting (void) +static int +inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min) { - td_thr_events_t events; - td_err_e err; -#ifdef HAVE_GNU_LIBC_VERSION_H - const char *libc_version; - int libc_major, libc_minor; -#endif - struct thread_db_info *info; - - info = get_thread_db_info (GET_PID (inferior_ptid)); + struct bound_minimal_symbol version_msym; + CORE_ADDR version_addr; + char *version; + int err, got, retval = 0; - /* We cannot use the thread event reporting facility if these - functions aren't available. */ - if (info->td_ta_event_addr_p == NULL - || info->td_ta_set_event_p == NULL - || info->td_ta_event_getmsg_p == NULL - || info->td_thr_event_enable_p == NULL) - return; - - /* Set the process wide mask saying which events we're interested in. */ - td_event_emptyset (&events); - td_event_addset (&events, TD_CREATE); - -#ifdef HAVE_GNU_LIBC_VERSION_H - /* The event reporting facility is broken for TD_DEATH events in - glibc 2.1.3, so don't enable it if we have glibc but a lower - version. */ - libc_version = gnu_get_libc_version (); - if (sscanf (libc_version, "%d.%d", &libc_major, &libc_minor) == 2 - && (libc_major > 2 || (libc_major == 2 && libc_minor > 1))) -#endif - td_event_addset (&events, TD_DEATH); + version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL); + if (version_msym.minsym == NULL) + return 0; - err = info->td_ta_set_event_p (info->thread_agent, &events); - if (err != TD_OK) + version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym); + got = target_read_string (version_addr, &version, 32, &err); + if (err == 0 && memchr (version, 0, got) == &version[got -1]) { - warning (_("Unable to set global thread event mask: %s"), - thread_db_err_str (err)); - return; - } + int major, minor; - /* Delete previous thread event breakpoints, if any. */ - remove_thread_event_breakpoints (); - info->td_create_bp_addr = 0; - info->td_death_bp_addr = 0; - - /* Set up the thread creation event. */ - err = enable_thread_event (TD_CREATE, &info->td_create_bp_addr); - if (err != TD_OK) - { - warning (_("Unable to get location for thread creation breakpoint: %s"), - thread_db_err_str (err)); - return; + retval = (sscanf (version, "%d.%d", &major, &minor) == 2 + && (major < ver_major_min + || (major == ver_major_min && minor < ver_minor_min))); } + xfree (version); - /* Set up the thread death event. */ - err = enable_thread_event (TD_DEATH, &info->td_death_bp_addr); - if (err != TD_OK) - { - warning (_("Unable to get location for thread death breakpoint: %s"), - thread_db_err_str (err)); - return; - } + return retval; } -/* Same as thread_db_find_new_threads_1, but silently ignore errors. */ +/* Similar as thread_db_find_new_threads_1, but try to silently ignore errors + if appropriate. -static void + Return 1 if the caller should abort libthread_db initialization. Return 0 + otherwise. */ + +static int thread_db_find_new_threads_silently (ptid_t ptid) { - volatile struct gdb_exception except; - TRY_CATCH (except, RETURN_MASK_ERROR) + TRY { thread_db_find_new_threads_2 (ptid, 1); } - if (except.reason < 0 && libthread_db_debug) + CATCH (except, RETURN_MASK_ERROR) { - exception_fprintf (gdb_stderr, except, - "Warning: thread_db_find_new_threads_silently: "); + 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; + } } + END_CATCH + + return 0; } /* Lookup a library in which given symbol resides. @@ -663,9 +507,20 @@ try_thread_db_load_1 (struct thread_db_info *info) /* Initialize pointers to the dynamic library functions we will use. Essential functions first. */ - info->td_init_p = verbose_dlsym (info->handle, "td_init"); - if (info->td_init_p == NULL) - return 0; +#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 0; \ + } while (0) + + CHK (TDB_VERBOSE_DLSYM (info, td_init)); err = info->td_init_p (); if (err != TD_OK) @@ -675,9 +530,7 @@ try_thread_db_load_1 (struct thread_db_info *info) return 0; } - info->td_ta_new_p = verbose_dlsym (info->handle, "td_ta_new"); - if (info->td_ta_new_p == NULL) - return 0; + CHK (TDB_VERBOSE_DLSYM (info, td_ta_new)); /* Initialize the structure that identifies the child process. */ info->proc_handle.ptid = inferior_ptid; @@ -687,8 +540,8 @@ try_thread_db_load_1 (struct thread_db_info *info) if (err != TD_OK) { if (libthread_db_debug) - printf_unfiltered (_("td_ta_new failed: %s\n"), - thread_db_err_str (err)); + fprintf_unfiltered (gdb_stdlog, _("td_ta_new failed: %s\n"), + thread_db_err_str (err)); else switch (err) { @@ -706,47 +559,72 @@ try_thread_db_load_1 (struct thread_db_info *info) return 0; } - info->td_ta_map_id2thr_p = verbose_dlsym (info->handle, "td_ta_map_id2thr"); - if (info->td_ta_map_id2thr_p == NULL) - return 0; + /* These are essential. */ + CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr)); + CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info)); - info->td_ta_map_lwp2thr_p = verbose_dlsym (info->handle, - "td_ta_map_lwp2thr"); - if (info->td_ta_map_lwp2thr_p == NULL) - return 0; + /* These are not essential. */ + TDB_DLSYM (info, td_thr_tls_get_addr); + TDB_DLSYM (info, td_thr_tlsbase); + + /* 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 (ptid_get_pid (inferior_ptid))) + 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 - info->td_ta_thr_iter_p = verbose_dlsym (info->handle, "td_ta_thr_iter"); if (info->td_ta_thr_iter_p == NULL) - return 0; + { + struct lwp_info *lp; + int pid = ptid_get_pid (inferior_ptid); - info->td_thr_validate_p = verbose_dlsym (info->handle, "td_thr_validate"); - if (info->td_thr_validate_p == NULL) - return 0; + linux_stop_and_wait_all_lwps (); - info->td_thr_get_info_p = verbose_dlsym (info->handle, "td_thr_get_info"); - if (info->td_thr_get_info_p == NULL) - return 0; + ALL_LWPS (lp) + if (ptid_get_pid (lp->ptid) == pid) + thread_from_lwp (lp->ptid); - /* These are not essential. */ - info->td_ta_event_addr_p = dlsym (info->handle, "td_ta_event_addr"); - info->td_ta_set_event_p = dlsym (info->handle, "td_ta_set_event"); - info->td_ta_clear_event_p = dlsym (info->handle, "td_ta_clear_event"); - info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg"); - info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable"); - info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr"); + linux_unstop_all_lwps (); + } + else if (thread_db_find_new_threads_silently (inferior_ptid) != 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 0; + } printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n")); - if (libthread_db_debug || *libthread_db_search_path) + if (*libthread_db_search_path || libthread_db_debug) { + struct ui_file *file; const char *library; - library = dladdr_to_soname (*info->td_ta_new_p); + library = dladdr_to_soname ((const void *) *info->td_ta_new_p); if (library == NULL) library = LIBTHREAD_DB_SO; - printf_unfiltered (_("Using host libthread_db library \"%s\".\n"), - library); + /* If we'd print this to gdb_stdout when debug output is + disabled, still print it to gdb_stdout if debug output is + enabled. User visible output should not depend on debug + settings. */ + file = *libthread_db_search_path != '\0' ? gdb_stdout : gdb_stdlog; + fprintf_unfiltered (file, _("Using host libthread_db library \"%s\".\n"), + library); } /* The thread library was detected. Activate the thread_db target @@ -754,16 +632,6 @@ try_thread_db_load_1 (struct thread_db_info *info) if (thread_db_list->next == NULL) push_target (&thread_db_ops); - /* Enable event reporting, but not when debugging a core file. */ - if (target_has_execution) - enable_thread_event_reporting (); - - /* There appears to be a bug in glibc-2.3.6: 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. Silently ignore such - errors, and let gdb enumerate threads again later. */ - thread_db_find_new_threads_silently (inferior_ptid); - return 1; } @@ -771,19 +639,40 @@ try_thread_db_load_1 (struct thread_db_info *info) relative, or just LIBTHREAD_DB. */ static int -try_thread_db_load (const char *library) +try_thread_db_load (const char *library, int check_auto_load_safe) { void *handle; struct thread_db_info *info; if (libthread_db_debug) - printf_unfiltered (_("Trying host libthread_db library: %s.\n"), - library); + fprintf_unfiltered (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) + fprintf_unfiltered (gdb_stdlog, _("open failed: %s.\n"), + safe_strerror (errno)); + return 0; + } + + if (!file_is_auto_load_safe (library, _("auto-load: Loading libthread-db " + "library \"%s\" from explicit " + "directory.\n"), + library)) + return 0; + } + handle = dlopen (library, RTLD_NOW); if (handle == NULL) { if (libthread_db_debug) - printf_unfiltered (_("dlopen failed: %s.\n"), dlerror ()); + fprintf_unfiltered (gdb_stdlog, _("dlopen failed: %s.\n"), dlerror ()); return 0; } @@ -797,73 +686,95 @@ try_thread_db_load (const char *library) const char *const libpath = dladdr_to_soname (td_init); if (libpath != NULL) - printf_unfiltered (_("Host %s resolved to: %s.\n"), + fprintf_unfiltered (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 (); + if (try_thread_db_load_1 (info)) return 1; /* This library "refused" to work on current inferior. */ - delete_thread_db_info (GET_PID (inferior_ptid)); + delete_thread_db_info (ptid_get_pid (inferior_ptid)); return 0; } /* Subroutine of try_thread_db_load_from_pdir to simplify it. - Try loading libthread_db from the same directory as OBJ. + 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 int -try_thread_db_load_from_pdir_1 (struct objfile *obj) +try_thread_db_load_from_pdir_1 (struct objfile *obj, const char *subdir) { struct cleanup *cleanup; char *path, *cp; int result; + const char *obj_name = objfile_name (obj); + int alloc_len; - if (obj->name[0] != '/') + if (obj_name[0] != '/') { warning (_("Expected absolute pathname for libpthread in the" - " inferior, but got %s."), obj->name); + " inferior, but got %s."), obj_name); return 0; } - path = xmalloc (strlen (obj->name) + 1 + strlen (LIBTHREAD_DB_SO) + 1); + alloc_len = (strlen (obj_name) + + (subdir ? strlen (subdir) + 1 : 0) + + 1 + strlen (LIBTHREAD_DB_SO) + 1); + path = (char *) xmalloc (alloc_len); cleanup = make_cleanup (xfree, path); - strcpy (path, obj->name); + strcpy (path, obj_name); cp = strrchr (path, '/'); /* This should at minimum hit the first character. */ gdb_assert (cp != NULL); - strcpy (cp + 1, LIBTHREAD_DB_SO); - result = try_thread_db_load (path); + cp[1] = '\0'; + if (subdir != NULL) + { + strcat (cp, subdir); + strcat (cp, "/"); + } + strcat (cp, LIBTHREAD_DB_SO); + + result = try_thread_db_load (path, 1); do_cleanups (cleanup); return result; } /* Handle $pdir in libthread-db-search-path. - Look for libthread_db in the directory of libpthread. + 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 int -try_thread_db_load_from_pdir (void) +try_thread_db_load_from_pdir (const char *subdir) { struct objfile *obj; + if (!auto_load_thread_db) + return 0; + ALL_OBJFILES (obj) - if (libpthread_name_p (obj->name)) + if (libpthread_name_p (objfile_name (obj))) { - if (try_thread_db_load_from_pdir_1 (obj)) + if (try_thread_db_load_from_pdir_1 (obj, subdir)) return 1; /* 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); + return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink, + subdir); return 0; } @@ -879,7 +790,7 @@ try_thread_db_load_from_pdir (void) static int try_thread_db_load_from_sdir (void) { - return try_thread_db_load (LIBTHREAD_DB_SO); + return try_thread_db_load (LIBTHREAD_DB_SO, 0); } /* Try to load libthread_db from directory DIR of length DIR_LEN. @@ -892,13 +803,17 @@ try_thread_db_load_from_dir (const char *dir, size_t dir_len) char *path; int result; - path = xmalloc (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1); + if (!auto_load_thread_db) + return 0; + + path = (char *) xmalloc (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1); cleanup = make_cleanup (xfree, path); memcpy (path, dir, dir_len); path[dir_len] = '/'; strcpy (path + dir_len + 1, LIBTHREAD_DB_SO); - result = try_thread_db_load (path); + + result = try_thread_db_load (path, 1); do_cleanups (cleanup); return result; @@ -911,37 +826,41 @@ try_thread_db_load_from_dir (const char *dir, size_t dir_len) static int thread_db_load_search (void) { - const char *search_path = libthread_db_search_path; - int rc = 0; + VEC (char_ptr) *dir_vec; + struct cleanup *cleanups; + char *this_dir; + int i, rc = 0; - while (*search_path) + dir_vec = dirnames_to_char_ptr_vec (libthread_db_search_path); + cleanups = make_cleanup_free_char_ptr_vec (dir_vec); + + for (i = 0; VEC_iterate (char_ptr, dir_vec, i, this_dir); ++i) { - const char *end = strchr (search_path, ':'); - const char *this_dir = search_path; + const int pdir_len = sizeof ("$pdir") - 1; size_t this_dir_len; - if (end) - { - this_dir_len = end - search_path; - search_path += this_dir_len + 1; - } - else - { - this_dir_len = strlen (this_dir); - search_path += this_dir_len; - } + this_dir_len = strlen (this_dir); - if (this_dir_len == sizeof ("$pdir") - 1 - && strncmp (this_dir, "$pdir", this_dir_len) == 0) + if (strncmp (this_dir, "$pdir", pdir_len) == 0 + && (this_dir[pdir_len] == '\0' + || this_dir[pdir_len] == '/')) { - if (try_thread_db_load_from_pdir ()) + char *subdir = NULL; + struct cleanup *free_subdir_cleanup + = make_cleanup (null_cleanup, NULL); + + if (this_dir[pdir_len] == '/') { - rc = 1; - break; + subdir = (char *) xmalloc (strlen (this_dir)); + make_cleanup (xfree, subdir); + strcpy (subdir, this_dir + pdir_len + 1); } + rc = try_thread_db_load_from_pdir (subdir); + do_cleanups (free_subdir_cleanup); + if (rc) + break; } - else if (this_dir_len == sizeof ("$sdir") - 1 - && strncmp (this_dir, "$sdir", this_dir_len) == 0) + else if (strcmp (this_dir, "$sdir") == 0) { if (try_thread_db_load_from_sdir ()) { @@ -959,8 +878,10 @@ thread_db_load_search (void) } } + do_cleanups (cleanups); if (libthread_db_debug) - printf_unfiltered (_("thread_db_load_search returning %d\n"), rc); + fprintf_unfiltered (gdb_stdlog, + _("thread_db_load_search returning %d\n"), rc); return rc; } @@ -972,7 +893,7 @@ has_libpthread (void) struct objfile *obj; ALL_OBJFILES (obj) - if (libpthread_name_p (obj->name)) + if (libpthread_name_p (objfile_name (obj))) return 1; return 0; @@ -986,7 +907,7 @@ thread_db_load (void) { struct thread_db_info *info; - info = get_thread_db_info (GET_PID (inferior_ptid)); + info = get_thread_db_info (ptid_get_pid (inferior_ptid)); if (info != NULL) return 1; @@ -1018,23 +939,6 @@ thread_db_load (void) return 0; } -static void -disable_thread_event_reporting (struct thread_db_info *info) -{ - if (info->td_ta_clear_event_p != NULL) - { - td_thr_events_t events; - - /* Set the process wide mask saying we aren't interested in any - events anymore. */ - td_event_fillset (&events); - info->td_ta_clear_event_p (info->thread_agent, &events); - } - - info->td_create_bp_addr = 0; - info->td_death_bp_addr = 0; -} - static void check_thread_signals (void) { @@ -1051,9 +955,9 @@ check_thread_signals (void) { if (sigismember (&mask, i)) { - if (signal_stop_update (target_signal_from_host (i), 0)) + if (signal_stop_update (gdb_signal_from_host (i), 0)) sigaddset (&thread_stop_set, i); - if (signal_print_update (target_signal_from_host (i), 0)) + if (signal_print_update (gdb_signal_from_host (i), 0)) sigaddset (&thread_print_set, i); thread_signals = 1; } @@ -1073,149 +977,125 @@ check_for_thread_db (void) 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) + if (objfile != NULL + /* libpthread with separate debug info has its debug info file already + loaded (and notified without successful thread_db initialization) + the time observer_notify_new_objfile 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_name_p (objfile_name (objfile)))) check_for_thread_db (); } -/* Attach to a new thread. This function is called when we receive a - TD_CREATE event or when we iterate over all threads and find one - that wasn't already in our list. Returns true on success. */ - -static int -attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, - const td_thrinfo_t *ti_p) +static void +check_pid_namespace_match (void) { - struct private_thread_info *private; - struct thread_info *tp = NULL; - td_err_e err; - struct thread_db_info *info; - - /* If we're being called after a TD_CREATE event, we may already - know about this thread. There are two ways this can happen. We - may have iterated over all threads between the thread creation - and the TD_CREATE event, for instance when the user has issued - the `info threads' command before the SIGTRAP for hitting the - thread creation breakpoint was reported. Alternatively, the - thread may have exited and a new one been created with the same - thread ID. In the first case we don't need to do anything; in - the second case we should discard information about the dead - thread and attach to the new one. */ - if (in_thread_list (ptid)) + /* Check is only relevant for local targets targets. */ + if (target_can_run (¤t_target)) { - tp = find_thread_ptid (ptid); - gdb_assert (tp != NULL); - - /* If tp->private is NULL, then GDB is already attached to this - thread, but we do not know anything about it. We can learn - about it here. This can only happen if we have some other - way besides libthread_db to notice new threads (i.e. - PTRACE_EVENT_CLONE); assume the same mechanism notices thread - exit, so this can not be a stale thread recreated with the - same ID. */ - if (tp->private != NULL) + /* 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 (ptid_get_pid (inferior_ptid), LINUX_NS_PID)) { - if (!tp->private->dying) - return 0; - - delete_thread (ptid); - tp = NULL; + warning (_ ("Target and debugger are in different PID " + "namespaces; thread lists and other data are " + "likely unreliable. " + "Connect to gdbserver inside the container.")); } } +} - if (target_has_execution) - check_thread_signals (); +/* This function is called via the inferior_created observer. + This handles the case of debugging statically linked executables. */ - if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE) - return 0; /* A zombie thread -- do not attach. */ +static void +thread_db_inferior_created (struct target_ops *target, int from_tty) +{ + check_pid_namespace_match (); + check_for_thread_db (); +} - /* Under GNU/Linux, we have to attach to each and every thread. */ - if (target_has_execution - && tp == NULL - && lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid))) < 0) - return 0; +/* Update the thread's state (what's displayed in "info threads"), + from libthread_db thread state information. */ - /* Construct the thread's private data. */ - private = xmalloc (sizeof (struct private_thread_info)); - memset (private, 0, sizeof (struct private_thread_info)); - - /* A thread ID of zero may mean the thread library has not initialized - yet. But we shouldn't even get here if that's the case. FIXME: - if we change GDB to always have at least one thread in the thread - list this will have to go somewhere else; maybe private == NULL - until the thread_db target claims it. */ - gdb_assert (ti_p->ti_tid != 0); - private->th = *th_p; - private->tid = ti_p->ti_tid; - - /* Add the thread to GDB's thread list. */ - if (tp == NULL) - add_thread_with_info (ptid, private); - else - tp->private = private; +static void +update_thread_state (struct private_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); +} - info = get_thread_db_info (GET_PID (ptid)); +/* 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. */ - /* Enable thread event reporting for this thread, except when - debugging a core file. */ - if (target_has_execution) - { - err = info->td_thr_event_enable_p (th_p, 1); - if (err != TD_OK) - error (_("Cannot enable thread event reporting for %s: %s"), - target_pid_to_str (ptid), thread_db_err_str (err)); - } +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) +{ + struct private_thread_info *priv; - return 1; -} + /* 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; -static void -detach_thread (ptid_t ptid) -{ - struct thread_info *thread_info; + /* Construct the thread's private data. */ + priv = XCNEW (struct private_thread_info); - /* Don't delete the thread now, because it still reports as active - until it has executed a few instructions after the event - breakpoint - if we deleted it now, "info threads" would cause us - to re-attach to it. Just mark it as having had a TD_DEATH - event. This means that we won't delete it from our thread list - until we notice that it's dead (via prune_threads), or until - something re-uses its thread ID. We'll report the thread exit - when the underlying LWP dies. */ - thread_info = find_thread_ptid (ptid); - gdb_assert (thread_info != NULL && thread_info->private != NULL); - thread_info->private->dying = 1; + 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 (ptid, priv); + else + tp->priv = priv; + + if (target_has_execution) + check_thread_signals (); + + return tp; } static void -thread_db_detach (struct target_ops *ops, char *args, int from_tty) +thread_db_detach (struct target_ops *ops, const char *args, int from_tty) { struct target_ops *target_beneath = find_target_beneath (ops); struct thread_db_info *info; - info = get_thread_db_info (GET_PID (inferior_ptid)); + info = get_thread_db_info (ptid_get_pid (inferior_ptid)); if (info) - { - if (target_has_execution) - { - disable_thread_event_reporting (info); - - /* Delete the old thread event breakpoints. Note that - unlike when mourning, we can remove them here because - there's still a live inferior to poke at. In any case, - GDB will not try to insert anything in the inferior when - removing a breakpoint. */ - remove_thread_event_breakpoints (); - } - - delete_thread_db_info (GET_PID (inferior_ptid)); - } + delete_thread_db_info (ptid_get_pid (inferior_ptid)); target_beneath->to_detach (target_beneath, args, from_tty); @@ -1227,99 +1107,6 @@ thread_db_detach (struct target_ops *ops, char *args, int from_tty) unpush_target (&thread_db_ops); } -/* Check if PID is currently stopped at the location of a thread event - breakpoint location. If it is, read the event message and act upon - the event. */ - -static void -check_event (ptid_t ptid) -{ - struct regcache *regcache = get_thread_regcache (ptid); - struct gdbarch *gdbarch = get_regcache_arch (regcache); - td_event_msg_t msg; - td_thrinfo_t ti; - td_err_e err; - CORE_ADDR stop_pc; - int loop = 0; - struct thread_db_info *info; - - info = get_thread_db_info (GET_PID (ptid)); - - /* Bail out early if we're not at a thread event breakpoint. */ - stop_pc = regcache_read_pc (regcache) - - gdbarch_decr_pc_after_break (gdbarch); - if (stop_pc != info->td_create_bp_addr - && stop_pc != info->td_death_bp_addr) - return; - - /* Access an lwp we know is stopped. */ - info->proc_handle.ptid = ptid; - - /* If we have only looked at the first thread before libpthread was - initialized, we may not know its thread ID yet. Make sure we do - before we add another thread to the list. */ - if (!have_threads (ptid)) - thread_db_find_new_threads_1 (ptid); - - /* If we are at a create breakpoint, we do not know what new lwp - was created and cannot specifically locate the event message for it. - We have to call td_ta_event_getmsg() to get - the latest message. Since we have no way of correlating whether - the event message we get back corresponds to our breakpoint, we must - loop and read all event messages, processing them appropriately. - This guarantees we will process the correct message before continuing - from the breakpoint. - - Currently, death events are not enabled. If they are enabled, - the death event can use the td_thr_event_getmsg() interface to - get the message specifically for that lwp and avoid looping - below. */ - - loop = 1; - - do - { - err = info->td_ta_event_getmsg_p (info->thread_agent, &msg); - if (err != TD_OK) - { - if (err == TD_NOMSG) - return; - - error (_("Cannot get thread event message: %s"), - thread_db_err_str (err)); - } - - err = info->td_thr_get_info_p (msg.th_p, &ti); - if (err != TD_OK) - error (_("Cannot get thread info: %s"), thread_db_err_str (err)); - - ptid = ptid_build (GET_PID (ptid), ti.ti_lid, 0); - - switch (msg.event) - { - case TD_CREATE: - /* Call attach_thread whether or not we already know about a - thread with this thread ID. */ - attach_thread (ptid, msg.th_p, &ti); - - break; - - case TD_DEATH: - - if (!in_thread_list (ptid)) - error (_("Spurious thread death event.")); - - detach_thread (ptid); - - break; - - default: - error (_("Spurious thread event.")); - } - } - while (loop); -} - static ptid_t thread_db_wait (struct target_ops *ops, ptid_t ptid, struct target_waitstatus *ourstatus, @@ -1330,14 +1117,16 @@ thread_db_wait (struct target_ops *ops, ptid = beneath->to_wait (beneath, ptid, ourstatus, options); - if (ourstatus->kind == TARGET_WAITKIND_IGNORE) - return ptid; - - if (ourstatus->kind == TARGET_WAITKIND_EXITED - || ourstatus->kind == TARGET_WAITKIND_SIGNALLED) - return ptid; + switch (ourstatus->kind) + { + case TARGET_WAITKIND_IGNORE: + case TARGET_WAITKIND_EXITED: + case TARGET_WAITKIND_THREAD_EXITED: + case TARGET_WAITKIND_SIGNALLED: + return ptid; + } - info = get_thread_db_info (GET_PID (ptid)); + info = get_thread_db_info (ptid_get_pid (ptid)); /* If this process isn't using thread_db, we're done. */ if (info == NULL) @@ -1347,38 +1136,15 @@ thread_db_wait (struct target_ops *ops, { /* New image, it may or may not end up using thread_db. Assume not unless we find otherwise. */ - delete_thread_db_info (GET_PID (ptid)); + delete_thread_db_info (ptid_get_pid (ptid)); if (!thread_db_list) unpush_target (&thread_db_ops); - /* Thread event breakpoints are deleted by - update_breakpoints_after_exec. */ - return ptid; } - /* If we do not know about the main thread yet, this would be a good time to - find it. */ - if (ourstatus->kind == TARGET_WAITKIND_STOPPED && !have_threads (ptid)) - thread_db_find_new_threads_1 (ptid); - - if (ourstatus->kind == TARGET_WAITKIND_STOPPED - && ourstatus->value.sig == TARGET_SIGNAL_TRAP) - /* Check for a thread event. */ - check_event (ptid); - - if (have_threads (ptid)) - { - /* Change ptids back into the higher level PID + TID format. If - the thread is dead and no longer on the thread list, we will - get back a dead ptid. This can occur if the thread death - event gets postponed by other simultaneous events. In such a - case, we want to just ignore the event and continue on. */ - - ptid = thread_from_lwp (ptid); - if (GET_PID (ptid) == -1) - ourstatus->kind = TARGET_WAITKIND_SPURIOUS; - } + /* Fill in the thread's user-level thread id and status. */ + thread_from_lwp (ptid); return ptid; } @@ -1388,14 +1154,10 @@ thread_db_mourn_inferior (struct target_ops *ops) { struct target_ops *target_beneath = find_target_beneath (ops); - delete_thread_db_info (GET_PID (inferior_ptid)); + delete_thread_db_info (ptid_get_pid (inferior_ptid)); target_beneath->to_mourn_inferior (target_beneath); - /* Delete the old thread event breakpoints. Do this after mourning - the inferior, so that we don't try to uninsert them. */ - remove_thread_event_breakpoints (); - /* Detach thread_db target ops. */ if (!thread_db_list) unpush_target (ops); @@ -1414,7 +1176,7 @@ find_new_threads_callback (const td_thrhandle_t *th_p, void *data) td_err_e err; ptid_t ptid; struct thread_info *tp; - struct callback_data *cb_data = data; + 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); @@ -1422,29 +1184,33 @@ find_new_threads_callback (const td_thrhandle_t *th_p, void *data) error (_("find_new_threads_callback: cannot get thread info: %s"), thread_db_err_str (err)); - if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE) - return 0; /* A zombie -- ignore. */ + 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) + fprintf_unfiltered (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. Just enable event reporting and otherwise ignore - it. */ + 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; - if (target_has_execution) - { - err = info->td_thr_event_enable_p (th_p, 1); - if (err != TD_OK) - error (_("Cannot enable thread event reporting for LWP %d: %s"), - (int) ti.ti_lid, thread_db_err_str (err)); - } - return 0; } @@ -1461,19 +1227,8 @@ find_new_threads_callback (const td_thrhandle_t *th_p, void *data) ptid = ptid_build (info->pid, ti.ti_lid, 0); tp = find_thread_ptid (ptid); - if (tp == NULL || tp->private == NULL) - { - if (attach_thread (ptid, th_p, &ti)) - cb_data->new_threads += 1; - else - /* Problem attaching this thread; perhaps it exited before we - could attach it? - This could mean that the thread list inside glibc itself is in - inconsistent state, and libthread_db could go on looping forever - (observed with glibc-2.3.6). To prevent that, terminate - iteration: thread_db_find_new_threads_2 will retry. */ - return 1; - } + if (tp == NULL || tp->priv == NULL) + record_thread (info, tp, ptid, th_p, &ti); return 0; } @@ -1485,14 +1240,16 @@ static int find_new_threads_once (struct thread_db_info *info, int iteration, td_err_e *errp) { - volatile struct gdb_exception except; struct callback_data data; td_err_e err = TD_ERR; data.info = info; data.new_threads = 0; - TRY_CATCH (except, RETURN_MASK_ERROR) + /* 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, @@ -1503,15 +1260,21 @@ find_new_threads_once (struct thread_db_info *info, int iteration, TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS); } + CATCH (except, RETURN_MASK_ERROR) + { + if (libthread_db_debug) + { + exception_fprintf (gdb_stdlog, except, + "Warning: find_new_threads_once: "); + } + } + END_CATCH if (libthread_db_debug) { - if (except.reason < 0) - exception_fprintf (gdb_stderr, except, - "Warning: find_new_threads_once: "); - - printf_filtered (_("Found %d new threads in iteration %d.\n"), - data.new_threads, iteration); + fprintf_unfiltered (gdb_stdlog, + _("Found %d new threads in iteration %d.\n"), + data.new_threads, iteration); } if (errp != NULL) @@ -1527,26 +1290,11 @@ find_new_threads_once (struct thread_db_info *info, int iteration, static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new) { - td_err_e err; + td_err_e err = TD_OK; struct thread_db_info *info; - int pid = ptid_get_pid (ptid); int i, loop; - if (target_has_execution) - { - struct lwp_info *lp; - - /* In linux, we can only read memory through a stopped lwp. */ - ALL_LWPS (lp, ptid) - if (lp->stopped && ptid_get_pid (lp->ptid) == pid) - break; - - if (!lp) - /* There is no stopped thread. Bail out. */ - return; - } - - info = get_thread_db_info (GET_PID (ptid)); + info = get_thread_db_info (ptid_get_pid (ptid)); /* Access an lwp we know is stopped. */ info->proc_handle.ptid = ptid; @@ -1557,17 +1305,18 @@ thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new) 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; ++i, ++loop) - if (find_new_threads_once (info, i, NULL) != 0) - /* Found some new threads. Restart the loop from beginning. */ - loop = -1; + 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)); - } + find_new_threads_once (info, 0, &err); + + if (err != TD_OK) + error (_("Cannot find new threads: %s"), thread_db_err_str (err)); } static void @@ -1576,65 +1325,86 @@ thread_db_find_new_threads_1 (ptid_t ptid) thread_db_find_new_threads_2 (ptid, 0); } -static int -update_thread_core (struct lwp_info *info, void *closure) -{ - info->core = linux_nat_core_of_thread_1 (info->ptid); - return 0; -} +/* Implement the to_update_thread_list target method for this + target. */ static void -thread_db_find_new_threads (struct target_ops *ops) +thread_db_update_thread_list (struct target_ops *ops) { struct thread_db_info *info; + struct inferior *inf; - info = get_thread_db_info (GET_PID (inferior_ptid)); + prune_threads (); - if (info == NULL) - return; - - thread_db_find_new_threads_1 (inferior_ptid); + ALL_INFERIORS (inf) + { + struct thread_info *thread; + + if (inf->pid == 0) + continue; + + info = get_thread_db_info (inf->pid); + if (info == NULL) + continue; + + thread = any_live_thread_of_process (inf->pid); + 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 (target_has_execution_1 (thread->ptid)) + continue; + + thread_db_find_new_threads_1 (thread->ptid); + } - if (target_has_execution) - iterate_over_lwps (minus_one_ptid /* iterate over all */, - update_thread_core, NULL); + /* Give the beneath target a chance to do extra processing. */ + ops->beneath->to_update_thread_list (ops->beneath); } -static char * +static const char * thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid) { struct thread_info *thread_info = find_thread_ptid (ptid); struct target_ops *beneath; - if (thread_info != NULL && thread_info->private != NULL) + if (thread_info != NULL && thread_info->priv != NULL) { static char buf[64]; thread_t tid; - tid = thread_info->private->tid; + tid = thread_info->priv->tid; snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)", - tid, GET_LWP (ptid)); + (unsigned long) tid, ptid_get_lwp (ptid)); return buf; } beneath = find_target_beneath (ops); - if (beneath->to_pid_to_str (beneath, ptid)) - return beneath->to_pid_to_str (beneath, ptid); - - return normal_pid_to_str (ptid); + return beneath->to_pid_to_str (beneath, ptid); } /* Return a string describing the state of the thread specified by INFO. */ -static char * -thread_db_extra_thread_info (struct thread_info *info) +static const char * +thread_db_extra_thread_info (struct target_ops *self, + struct thread_info *info) { - if (info->private == NULL) + if (info->priv == NULL) return NULL; - if (info->private->dying) + if (info->priv->dying) return "Exiting"; return NULL; @@ -1652,36 +1422,54 @@ thread_db_get_thread_local_address (struct target_ops *ops, struct thread_info *thread_info; struct target_ops *beneath; - /* If we have not discovered any threads yet, check now. */ - if (!have_threads (ptid)) - thread_db_find_new_threads_1 (ptid); - /* Find the matching thread. */ thread_info = find_thread_ptid (ptid); - if (thread_info != NULL && thread_info->private != NULL) + /* We may not have discovered the thread yet. */ + if (thread_info != NULL && thread_info->priv == NULL) + thread_info = thread_from_lwp (ptid); + + if (thread_info != NULL && thread_info->priv != NULL) { td_err_e err; psaddr_t address; struct thread_db_info *info; - info = get_thread_db_info (GET_PID (ptid)); - - /* 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")); - - /* Caller should have verified that lm != 0. */ - gdb_assert (lm != 0); + info = get_thread_db_info (ptid_get_pid (ptid)); /* Finally, get the address of the variable. */ - /* 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 (&thread_info->private->th, - (psaddr_t)(uintptr_t) lm, - offset, &address); + 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 (&thread_info->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 (&thread_info->priv->th, + 1, &address); + address = (char *) address + offset; + } #ifdef THREAD_DB_HAS_TD_NOTALLOC /* The memory hasn't been allocated, yet. */ @@ -1707,53 +1495,29 @@ thread_db_get_thread_local_address (struct target_ops *ops, } beneath = find_target_beneath (ops); - if (beneath->to_get_thread_local_address) - return beneath->to_get_thread_local_address (beneath, ptid, lm, offset); - else - throw_error (TLS_GENERIC_ERROR, - _("TLS not supported on this target")); -} - -/* Callback routine used to find a thread based on the TID part of - its PTID. */ - -static int -thread_db_find_thread_from_tid (struct thread_info *thread, void *data) -{ - long *tid = (long *) data; - - if (thread->private->tid == *tid) - return 1; - - return 0; + return beneath->to_get_thread_local_address (beneath, ptid, lm, offset); } /* Implement the to_get_ada_task_ptid target method for this target. */ static ptid_t -thread_db_get_ada_task_ptid (long lwp, long thread) +thread_db_get_ada_task_ptid (struct target_ops *self, long lwp, long thread) { - struct thread_info *thread_info; - - thread_db_find_new_threads_1 (inferior_ptid); - thread_info = iterate_over_threads (thread_db_find_thread_from_tid, &thread); - - gdb_assert (thread_info != NULL); - - return (thread_info->ptid); + /* NPTL uses a 1:1 model, so the LWP id suffices. */ + return ptid_build (ptid_get_pid (inferior_ptid), lwp, 0); } static void thread_db_resume (struct target_ops *ops, - ptid_t ptid, int step, enum target_signal signo) + ptid_t ptid, int step, enum gdb_signal signo) { struct target_ops *beneath = find_target_beneath (ops); struct thread_db_info *info; if (ptid_equal (ptid, minus_one_ptid)) - info = get_thread_db_info (GET_PID (inferior_ptid)); + info = get_thread_db_info (ptid_get_pid (inferior_ptid)); else - info = get_thread_db_info (GET_PID (ptid)); + info = get_thread_db_info (ptid_get_pid (ptid)); /* This workaround is only needed for child fork lwps stopped in a PTRACE_O_TRACEFORK event. When the inferior is resumed, the @@ -1764,6 +1528,151 @@ thread_db_resume (struct target_ops *ops, beneath->to_resume (beneath, ptid, step, signo); } +/* qsort 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 int +info_auto_load_libthread_db_compare (const void *ap, const void *bp) +{ + struct thread_db_info *a = *(struct thread_db_info **) ap; + struct thread_db_info *b = *(struct thread_db_info **) bp; + int retval; + + retval = strcmp (a->filename, b->filename); + if (retval) + return retval; + + return (a->pid > b->pid) - (a->pid - b->pid); +} + +/* Implement 'info auto-load libthread-db'. */ + +static void +info_auto_load_libthread_db (char *args, int from_tty) +{ + struct ui_out *uiout = current_uiout; + const char *cs = args ? args : ""; + struct thread_db_info *info, **array; + unsigned info_count, unique_filenames; + size_t max_filename_len, max_pids_len, pids_len; + struct cleanup *back_to; + char *pids; + int i; + + cs = skip_spaces_const (cs); + if (*cs) + error (_("'info auto-load libthread-db' does not accept any parameters")); + + info_count = 0; + for (info = thread_db_list; info; info = info->next) + if (info->filename != NULL) + info_count++; + + array = XNEWVEC (struct thread_db_info *, info_count); + back_to = make_cleanup (xfree, array); + + info_count = 0; + for (info = thread_db_list; info; info = info->next) + if (info->filename != NULL) + array[info_count++] = info; + + /* Sort ARRAY by filenames and PIDs. */ + + qsort (array, info_count, sizeof (*array), + 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; + max_pids_len = 0; + pids_len = 0; + for (i = 0; i < info_count; 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 (", "); + max_pids_len = std::max (max_pids_len, pids_len); + } + pids_len = 0; + } + pids_len += this_pid_len + strlen (", "); + } + if (i) + { + pids_len -= strlen (", "); + max_pids_len = std::max (max_pids_len, pids_len); + } + + /* Table header shifted right by preceding "libthread-db: " would not match + its columns. */ + if (info_count > 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 (); + + pids = (char *) xmalloc (max_pids_len + 1); + make_cleanup (xfree, pids); + + /* Note I is incremented inside the cycle, not at its end. */ + for (i = 0; i < info_count;) + { + ui_out_emit_tuple tuple_emitter (uiout, NULL); + char *pids_end; + + info = array[i]; + uiout->field_string ("filename", info->filename); + pids_end = pids; + + while (i < info_count && strcmp (info->filename, + array[i]->filename) == 0) + { + if (pids_end != pids) + { + *pids_end++ = ','; + *pids_end++ = ' '; + } + pids_end += xsnprintf (pids_end, + &pids[max_pids_len + 1] - pids_end, + "%u", array[i]->pid); + gdb_assert (pids_end < &pids[max_pids_len + 1]); + + i++; + } + *pids_end = '\0'; + + uiout->field_string ("pids", pids); + + uiout->text ("\n"); + } + } + + do_cleanups (back_to); + + if (info_count == 0) + uiout->message (_("No auto-loaded libthread-db.\n")); +} + static void init_thread_db_ops (void) { @@ -1774,7 +1683,7 @@ init_thread_db_ops (void) thread_db_ops.to_wait = thread_db_wait; thread_db_ops.to_resume = thread_db_resume; thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior; - thread_db_ops.to_find_new_threads = thread_db_find_new_threads; + thread_db_ops.to_update_thread_list = thread_db_update_thread_list; thread_db_ops.to_pid_to_str = thread_db_pid_to_str; thread_db_ops.to_stratum = thread_stratum; thread_db_ops.to_has_thread_control = tc_schedlock; @@ -1783,6 +1692,8 @@ init_thread_db_ops (void) thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info; thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid; thread_db_ops.to_magic = OPS_MAGIC; + + complete_target_initialization (&thread_db_ops); } /* Provide a prototype to silence -Wmissing-prototypes. */ @@ -1792,14 +1703,12 @@ void _initialize_thread_db (void) { init_thread_db_ops (); - add_target (&thread_db_ops); /* 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 mutiple versions of glibc, - compiled with LinuxThreads or NPTL, and until there is - a running inferior, we can't tell which libthread_db is - the correct one to load. */ + 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. */ libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH); @@ -1816,15 +1725,37 @@ Setting the search path to an empty list resets it to its default value."), NULL, &setlist, &showlist); - add_setshow_zinteger_cmd ("libthread-db", class_maintenance, - &libthread_db_debug, _("\ + 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); + 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 options 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 ourselves to objfile event chain. */ observer_attach_new_objfile (thread_db_new_objfile); + + /* 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. */ + observer_attach_inferior_created (thread_db_inferior_created); }