/* libthread_db assisted debugging support, generic parts. Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007 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 "gdb_assert.h" #include <dlfcn.h> #include "gdb_proc_service.h" #include "gdb_thread_db.h" #include "bfd.h" #include "exceptions.h" #include "gdbthread.h" #include "inferior.h" #include "symfile.h" #include "objfiles.h" #include "target.h" #include "regcache.h" #include "solib-svr4.h" #include "gdbcore.h" #include "observer.h" #include "linux-nat.h" #include <signal.h> #ifdef HAVE_GNU_LIBC_VERSION_H #include <gnu/libc-version.h> #endif #ifndef LIBTHREAD_DB_SO #define LIBTHREAD_DB_SO "libthread_db.so.1" #endif /* If we're running on GNU/Linux, we must explicitly attach to any new threads. */ /* This module's target vector. */ static struct target_ops thread_db_ops; /* The target vector that we call for things this module can't handle. */ static struct target_ops *target_beneath; /* Non-zero if we're using this module's target vector. */ static int using_thread_db; /* Non-zero if we have determined the signals used by the threads library. */ static int thread_signals; static sigset_t thread_stop_set; static sigset_t thread_print_set; /* Structure that identifies the child process for the <proc_service.h> interface. */ static struct ps_prochandle proc_handle; /* Connection to the libthread_db library. */ static td_thragent_t *thread_agent; /* Pointers to the libthread_db functions. */ static td_err_e (*td_init_p) (void); static td_err_e (*td_ta_new_p) (struct ps_prochandle * ps, td_thragent_t **ta); static td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt, td_thrhandle_t *__th); static td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta, lwpid_t lwpid, td_thrhandle_t *th); static 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); static td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta, td_event_e event, td_notify_t *ptr); static td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta, td_thr_events_t *event); static td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta, td_event_msg_t *msg); static td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th); static td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th, td_thrinfo_t *infop); static td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th, int event); static td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th, void *map_address, size_t offset, void **address); /* 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. */ static CORE_ADDR td_create_bp_addr; /* Location of the thread death event breakpoint. */ static CORE_ADDR td_death_bp_addr; /* Prototypes for local functions. */ static void thread_db_find_new_threads (void); static void attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p, int verbose); static void detach_thread (ptid_t ptid, int verbose); /* Building process ids. */ #define GET_PID(ptid) ptid_get_pid (ptid) #define GET_LWP(ptid) ptid_get_lwp (ptid) #define GET_THREAD(ptid) ptid_get_tid (ptid) #define is_lwp(ptid) (GET_LWP (ptid) != 0) #define is_thread(ptid) (GET_THREAD (ptid) != 0) #define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0) /* Use "struct private_thread_info" to cache thread state. This is a substantial optimization. */ struct private_thread_info { /* Flag set when we see a TD_DEATH event for this thread. */ unsigned int dying:1; /* Cached thread state. */ unsigned int th_valid:1; unsigned int ti_valid:1; td_thrhandle_t th; td_thrinfo_t ti; }; static 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; } } /* 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 *dummy) { return 1; } static int have_threads (void) { return iterate_over_threads (have_threads_callback, NULL) != NULL; } /* 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 *infop) { td_thrinfo_t ti; td_err_e err; struct thread_info *thread_info; ptid_t thread_ptid; err = 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 (GET_PID (inferior_ptid), ti.ti_lid, ti.ti_tid); thread_info = find_thread_pid (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) { if (infop != NULL) *(struct thread_info **) infop = thread_info; if (thread_info != NULL) { memcpy (&thread_info->private->th, thp, sizeof (*thp)); thread_info->private->th_valid = 1; memcpy (&thread_info->private->ti, &ti, sizeof (ti)); thread_info->private->ti_valid = 1; } return TD_THR_ZOMBIE; } if (thread_info == NULL) { /* New thread. Attach to it now (why wait?). */ attach_thread (thread_ptid, thp, &ti, 1); thread_info = find_thread_pid (thread_ptid); gdb_assert (thread_info != NULL); } memcpy (&thread_info->private->th, thp, sizeof (*thp)); thread_info->private->th_valid = 1; memcpy (&thread_info->private->ti, &ti, sizeof (ti)); thread_info->private->ti_valid = 1; if (infop != NULL) *(struct thread_info **) infop = thread_info; return 0; } /* Accessor functions for the thread_db information, with caching. */ static void thread_db_map_id2thr (struct thread_info *thread_info, int fatal) { td_err_e err; if (thread_info->private->th_valid) return; err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (thread_info->ptid), &thread_info->private->th); if (err != TD_OK) { if (fatal) error (_("Cannot find thread %ld: %s"), (long) GET_THREAD (thread_info->ptid), thread_db_err_str (err)); } else thread_info->private->th_valid = 1; } /* Convert between user-level thread ids and LWP ids. */ static ptid_t thread_from_lwp (ptid_t ptid) { td_thrhandle_t th; td_err_e err; struct thread_info *thread_info; ptid_t thread_ptid; if (GET_LWP (ptid) == 0) ptid = BUILD_LWP (GET_PID (ptid), GET_PID (ptid)); gdb_assert (is_lwp (ptid)); err = td_ta_map_lwp2thr_p (thread_agent, 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)); thread_info = NULL; /* 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. */ if (thread_get_info_callback (&th, &thread_info) == TD_THR_ZOMBIE && thread_info == NULL) return pid_to_ptid (-1); gdb_assert (thread_info && thread_info->private->ti_valid); return ptid_build (GET_PID (ptid), GET_LWP (ptid), thread_info->private->ti.ti_tid); } static ptid_t lwp_from_thread (ptid_t ptid) { return BUILD_LWP (GET_LWP (ptid), GET_PID (ptid)); } void thread_db_init (struct target_ops *target) { target_beneath = target; } 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; } static int thread_db_load (void) { void *handle; td_err_e err; handle = dlopen (LIBTHREAD_DB_SO, RTLD_NOW); if (handle == NULL) { fprintf_filtered (gdb_stderr, "\n\ndlopen failed on '%s' - %s\n", LIBTHREAD_DB_SO, dlerror ()); fprintf_filtered (gdb_stderr, "GDB will not be able to debug pthreads.\n\n"); return 0; } /* Initialize pointers to the dynamic library functions we will use. Essential functions first. */ td_init_p = verbose_dlsym (handle, "td_init"); if (td_init_p == NULL) return 0; td_ta_new_p = verbose_dlsym (handle, "td_ta_new"); if (td_ta_new_p == NULL) return 0; td_ta_map_id2thr_p = verbose_dlsym (handle, "td_ta_map_id2thr"); if (td_ta_map_id2thr_p == NULL) return 0; td_ta_map_lwp2thr_p = verbose_dlsym (handle, "td_ta_map_lwp2thr"); if (td_ta_map_lwp2thr_p == NULL) return 0; td_ta_thr_iter_p = verbose_dlsym (handle, "td_ta_thr_iter"); if (td_ta_thr_iter_p == NULL) return 0; td_thr_validate_p = verbose_dlsym (handle, "td_thr_validate"); if (td_thr_validate_p == NULL) return 0; td_thr_get_info_p = verbose_dlsym (handle, "td_thr_get_info"); if (td_thr_get_info_p == NULL) return 0; /* Initialize the library. */ err = td_init_p (); if (err != TD_OK) { warning (_("Cannot initialize libthread_db: %s"), thread_db_err_str (err)); return 0; } /* These are not essential. */ td_ta_event_addr_p = dlsym (handle, "td_ta_event_addr"); td_ta_set_event_p = dlsym (handle, "td_ta_set_event"); td_ta_event_getmsg_p = dlsym (handle, "td_ta_event_getmsg"); td_thr_event_enable_p = dlsym (handle, "td_thr_event_enable"); td_thr_tls_get_addr_p = dlsym (handle, "td_thr_tls_get_addr"); return 1; } static td_err_e enable_thread_event (td_thragent_t *thread_agent, int event, CORE_ADDR *bp) { td_notify_t notify; td_err_e err; /* Get the breakpoint address for thread EVENT. */ err = td_ta_event_addr_p (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 (current_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 ((*bp)); return TD_OK; } static void enable_thread_event_reporting (void) { td_thr_events_t events; td_notify_t notify; td_err_e err; #ifdef HAVE_GNU_LIBC_VERSION_H const char *libc_version; int libc_major, libc_minor; #endif /* We cannot use the thread event reporting facility if these functions aren't available. */ if (td_ta_event_addr_p == NULL || td_ta_set_event_p == NULL || td_ta_event_getmsg_p == NULL || 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); err = td_ta_set_event_p (thread_agent, &events); if (err != TD_OK) { warning (_("Unable to set global thread event mask: %s"), thread_db_err_str (err)); return; } /* Delete previous thread event breakpoints, if any. */ remove_thread_event_breakpoints (); td_create_bp_addr = 0; td_death_bp_addr = 0; /* Set up the thread creation event. */ err = enable_thread_event (thread_agent, TD_CREATE, &td_create_bp_addr); if (err != TD_OK) { warning (_("Unable to get location for thread creation breakpoint: %s"), thread_db_err_str (err)); return; } /* Set up the thread death event. */ err = enable_thread_event (thread_agent, TD_DEATH, &td_death_bp_addr); if (err != TD_OK) { warning (_("Unable to get location for thread death breakpoint: %s"), thread_db_err_str (err)); return; } } static void disable_thread_event_reporting (void) { td_thr_events_t events; /* Set the process wide mask saying we aren't interested in any events anymore. */ td_event_emptyset (&events); td_ta_set_event_p (thread_agent, &events); /* Delete thread event breakpoints, if any. */ remove_thread_event_breakpoints (); td_create_bp_addr = 0; td_death_bp_addr = 0; } static void check_thread_signals (void) { #ifdef GET_THREAD_SIGNALS if (!thread_signals) { sigset_t mask; int i; GET_THREAD_SIGNALS (&mask); sigemptyset (&thread_stop_set); sigemptyset (&thread_print_set); for (i = 1; i < NSIG; i++) { if (sigismember (&mask, i)) { if (signal_stop_update (target_signal_from_host (i), 0)) sigaddset (&thread_stop_set, i); if (signal_print_update (target_signal_from_host (i), 0)) sigaddset (&thread_print_set, i); thread_signals = 1; } } } #endif } /* 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. */ void check_for_thread_db (void) { td_err_e err; static int already_loaded; /* Do nothing if we couldn't load libthread_db.so.1. */ if (td_ta_new_p == NULL) return; /* First time through, report that libthread_db was successfuly loaded. Can't print this in in thread_db_load as, at that stage, the interpreter and it's console haven't started. */ if (!already_loaded) { Dl_info info; const char *library = NULL; if (dladdr ((*td_ta_new_p), &info) != 0) library = info.dli_fname; /* Try dlinfo? */ if (library == NULL) /* Paranoid - don't let a NULL path slip through. */ library = LIBTHREAD_DB_SO; if (info_verbose) printf_unfiltered (_("Using host libthread_db library \"%s\".\n"), library); already_loaded = 1; } if (using_thread_db) /* Nothing to do. The thread library was already detected and the target vector was already activated. */ return; /* Don't attempt to use thread_db on targets which can not run (executables not running yet, core files) for now. */ if (!target_has_execution) return; /* Don't attempt to use thread_db for remote targets. */ if (!target_can_run (¤t_target)) return; /* Initialize the structure that identifies the child process. */ proc_handle.pid = GET_PID (inferior_ptid); /* Now attempt to open a connection to the thread library. */ err = td_ta_new_p (&proc_handle, &thread_agent); switch (err) { case TD_NOLIBTHREAD: /* No thread library was detected. */ break; case TD_OK: printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n")); /* The thread library was detected. Activate the thread_db target. */ push_target (&thread_db_ops); using_thread_db = 1; enable_thread_event_reporting (); thread_db_find_new_threads (); break; default: warning (_("Cannot initialize thread debugging library: %s"), thread_db_err_str (err)); break; } } static void thread_db_new_objfile (struct objfile *objfile) { if (objfile != NULL) 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. */ static void attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p, int verbose) { struct thread_info *tp; td_err_e err; /* 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)) { tp = find_thread_pid (ptid); gdb_assert (tp != NULL); if (!tp->private->dying) return; delete_thread (ptid); } check_thread_signals (); if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE) return; /* A zombie thread -- do not attach. */ /* Under GNU/Linux, we have to attach to each and every thread. */ if (lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)), 0) < 0) return; /* Add the thread to GDB's thread list. */ tp = add_thread (ptid); tp->private = xmalloc (sizeof (struct private_thread_info)); memset (tp->private, 0, sizeof (struct private_thread_info)); if (verbose) printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid)); /* Enable thread event reporting for this thread. */ err = 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 void detach_thread (ptid_t ptid, int verbose) { struct thread_info *thread_info; if (verbose) printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (ptid)); /* 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. */ thread_info = find_thread_pid (ptid); gdb_assert (thread_info != NULL); thread_info->private->dying = 1; } static void thread_db_detach (char *args, int from_tty) { disable_thread_event_reporting (); /* There's no need to save & restore inferior_ptid here, since the inferior is not supposed to survive this function call. */ inferior_ptid = lwp_from_thread (inferior_ptid); target_beneath->to_detach (args, from_tty); /* Should this be done by detach_command? */ target_mourn_inferior (); } static int clear_lwpid_callback (struct thread_info *thread, void *dummy) { /* If we know that our thread implementation is 1-to-1, we could save a certain amount of information; it's not clear how much, so we are always conservative. */ thread->private->th_valid = 0; thread->private->ti_valid = 0; return 0; } static void thread_db_resume (ptid_t ptid, int step, enum target_signal signo) { struct cleanup *old_chain = save_inferior_ptid (); if (GET_PID (ptid) == -1) inferior_ptid = lwp_from_thread (inferior_ptid); else if (is_thread (ptid)) ptid = lwp_from_thread (ptid); /* Clear cached data which may not be valid after the resume. */ iterate_over_threads (clear_lwpid_callback, NULL); target_beneath->to_resume (ptid, step, signo); do_cleanups (old_chain); } /* 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) { td_event_msg_t msg; td_thrinfo_t ti; td_err_e err; CORE_ADDR stop_pc; int loop = 0; /* Bail out early if we're not at a thread event breakpoint. */ stop_pc = read_pc_pid (ptid) - gdbarch_decr_pc_after_break (current_gdbarch); if (stop_pc != td_create_bp_addr && stop_pc != td_death_bp_addr) return; /* 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 = td_ta_event_getmsg_p (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 = 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, ti.ti_tid); 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, 1); break; case TD_DEATH: if (!in_thread_list (ptid)) error (_("Spurious thread death event.")); detach_thread (ptid, 1); break; default: error (_("Spurious thread event.")); } } while (loop); } static ptid_t thread_db_wait (ptid_t ptid, struct target_waitstatus *ourstatus) { extern ptid_t trap_ptid; if (GET_PID (ptid) != -1 && is_thread (ptid)) ptid = lwp_from_thread (ptid); ptid = target_beneath->to_wait (ptid, ourstatus); if (ourstatus->kind == TARGET_WAITKIND_EXITED || ourstatus->kind == TARGET_WAITKIND_SIGNALLED) return pid_to_ptid (-1); if (ourstatus->kind == TARGET_WAITKIND_EXECD) { remove_thread_event_breakpoints (); unpush_target (&thread_db_ops); using_thread_db = 0; return pid_to_ptid (GET_PID (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 ()) thread_db_find_new_threads (); if (ourstatus->kind == TARGET_WAITKIND_STOPPED && ourstatus->value.sig == TARGET_SIGNAL_TRAP) /* Check for a thread event. */ check_event (ptid); if (have_threads ()) { /* 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. */ if (!ptid_equal (trap_ptid, null_ptid)) trap_ptid = thread_from_lwp (trap_ptid); ptid = thread_from_lwp (ptid); if (GET_PID (ptid) == -1) ourstatus->kind = TARGET_WAITKIND_SPURIOUS; } return ptid; } static void thread_db_kill (void) { /* There's no need to save & restore inferior_ptid here, since the inferior isn't supposed to survive this function call. */ inferior_ptid = lwp_from_thread (inferior_ptid); target_beneath->to_kill (); } static void thread_db_mourn_inferior (void) { /* Forget about the child's process ID. We shouldn't need it anymore. */ proc_handle.pid = 0; target_beneath->to_mourn_inferior (); /* 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. */ unpush_target (&thread_db_ops); using_thread_db = 0; } static int find_new_threads_callback (const td_thrhandle_t *th_p, void *data) { td_thrinfo_t ti; td_err_e err; ptid_t ptid; err = 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_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE) return 0; /* A zombie -- ignore. */ ptid = ptid_build (GET_PID (inferior_ptid), ti.ti_lid, ti.ti_tid); 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. */ err = 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)); return 0; } if (!in_thread_list (ptid)) attach_thread (ptid, th_p, &ti, 1); return 0; } static void thread_db_find_new_threads (void) { td_err_e err; /* Iterate over all user-space threads to discover new threads. */ err = td_ta_thr_iter_p (thread_agent, find_new_threads_callback, NULL, TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY, TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS); if (err != TD_OK) error (_("Cannot find new threads: %s"), thread_db_err_str (err)); } static char * thread_db_pid_to_str (ptid_t ptid) { if (is_thread (ptid)) { static char buf[64]; struct thread_info *thread_info; thread_info = find_thread_pid (ptid); if (thread_info == NULL) snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld) (Missing)", GET_THREAD (ptid), GET_LWP (ptid)); else snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)", GET_THREAD (ptid), GET_LWP (ptid)); return buf; } if (target_beneath->to_pid_to_str (ptid)) return target_beneath->to_pid_to_str (ptid); return normal_pid_to_str (ptid); } /* Return a string describing the state of the thread specified by INFO. */ static char * thread_db_extra_thread_info (struct thread_info *info) { if (info->private->dying) return "Exiting"; return NULL; } /* Return 1 if this thread has the same LWP as the passed PTID. */ static int same_ptid_callback (struct thread_info *thread, void *arg) { ptid_t *ptid_p = arg; return GET_LWP (thread->ptid) == GET_LWP (*ptid_p); } /* 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. */ static CORE_ADDR thread_db_get_thread_local_address (ptid_t ptid, CORE_ADDR lm, CORE_ADDR offset) { /* If we have not discovered any threads yet, check now. */ if (!is_thread (ptid) && !have_threads ()) thread_db_find_new_threads (); /* Try to find a matching thread if we still have the LWP ID instead of the thread ID. */ if (!is_thread (ptid)) { struct thread_info *thread; thread = iterate_over_threads (same_ptid_callback, &ptid); if (thread != NULL) ptid = thread->ptid; } if (is_thread (ptid)) { td_err_e err; void *address; struct thread_info *thread_info; /* glibc doesn't provide the needed interface. */ if (!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); /* Get info about the thread. */ thread_info = find_thread_pid (ptid); gdb_assert (thread_info); thread_db_map_id2thr (thread_info, 1); /* Finally, get the address of the variable. */ err = td_thr_tls_get_addr_p (&thread_info->private->th, (void *)(size_t) lm, offset, &address); #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 (exec_bfd); return (bfd_get_sign_extend_vma (exec_bfd) > 0 ? (CORE_ADDR) (intptr_t) address : (CORE_ADDR) (uintptr_t) address); } if (target_beneath->to_get_thread_local_address) return target_beneath->to_get_thread_local_address (ptid, lm, offset); else throw_error (TLS_GENERIC_ERROR, _("TLS not supported on this target")); } static void init_thread_db_ops (void) { thread_db_ops.to_shortname = "multi-thread"; thread_db_ops.to_longname = "multi-threaded child process."; thread_db_ops.to_doc = "Threads and pthreads support."; thread_db_ops.to_detach = thread_db_detach; thread_db_ops.to_resume = thread_db_resume; thread_db_ops.to_wait = thread_db_wait; thread_db_ops.to_kill = thread_db_kill; 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_pid_to_str = thread_db_pid_to_str; thread_db_ops.to_stratum = thread_stratum; thread_db_ops.to_has_thread_control = tc_schedlock; thread_db_ops.to_get_thread_local_address = thread_db_get_thread_local_address; thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info; thread_db_ops.to_magic = OPS_MAGIC; } void _initialize_thread_db (void) { /* Only initialize the module if we can load libthread_db. */ if (thread_db_load ()) { init_thread_db_ops (); add_target (&thread_db_ops); /* Add ourselves to objfile event chain. */ observer_attach_new_objfile (thread_db_new_objfile); } }