diff options
Diffstat (limited to 'gdb/linux-thread-db.c')
| -rw-r--r-- | gdb/linux-thread-db.c | 1370 |
1 files changed, 1370 insertions, 0 deletions
diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c new file mode 100644 index 0000000..65d9fd5 --- /dev/null +++ b/gdb/linux-thread-db.c @@ -0,0 +1,1370 @@ +/* libthread_db assisted debugging support, generic parts. + + Copyright 1999, 2000, 2001, 2003, 2004 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 2 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include "defs.h" + +#include "gdb_assert.h" +#include <dlfcn.h> +#include "gdb_proc_service.h" +#include "gdb_thread_db.h" + +#include "bfd.h" +#include "gdbthread.h" +#include "inferior.h" +#include "symfile.h" +#include "objfiles.h" +#include "target.h" +#include "regcache.h" +#include "solib-svr4.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. */ + +/* FIXME: There is certainly some room for improvements: + - Cache LWP ids. + - Bypass libthread_db when fetching or storing registers for + threads bound to a LWP. */ + +/* 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; + +/* Pointer to the next function on the objfile event chain. */ +static void (*target_new_objfile_chain) (struct objfile * objfile); + +/* 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_getfpregs_p) (const td_thrhandle_t *th, + gdb_prfpregset_t *regset); +static td_err_e (*td_thr_getgregs_p) (const td_thrhandle_t *th, + prgregset_t gregs); +static td_err_e (*td_thr_setfpregs_p) (const td_thrhandle_t *th, + const gdb_prfpregset_t *fpregs); +static td_err_e (*td_thr_setgregs_p) (const td_thrhandle_t *th, + prgregset_t gregs); +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) +#define BUILD_THREAD(tid, pid) ptid_build (pid, 0, tid) + + +/* 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"; + default: + snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err); + return buf; + } +} + +static char * +thread_db_state_str (td_thr_state_e state) +{ + static char buf[64]; + + switch (state) + { + case TD_THR_STOPPED: + return "stopped by debugger"; + case TD_THR_RUN: + return "runnable"; + case TD_THR_ACTIVE: + return "active"; + case TD_THR_ZOMBIE: + return "zombie"; + case TD_THR_SLEEP: + return "sleeping"; + case TD_THR_STOPPED_ASLEEP: + return "stopped by debugger AND blocked"; + default: + snprintf (buf, sizeof (buf), "unknown thread_db state %d", state); + return buf; + } +} + +/* 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 = BUILD_THREAD (ti.ti_tid, GET_PID (inferior_ptid)); + 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; +} + +static td_thrinfo_t * +thread_db_get_info (struct thread_info *thread_info) +{ + td_err_e err; + + if (thread_info->private->ti_valid) + return &thread_info->private->ti; + + if (!thread_info->private->th_valid) + thread_db_map_id2thr (thread_info, 1); + + err = + td_thr_get_info_p (&thread_info->private->th, &thread_info->private->ti); + if (err != TD_OK) + error ("thread_db_get_info: cannot get thread info: %s", + thread_db_err_str (err)); + + thread_info->private->ti_valid = 1; + return &thread_info->private->ti; +} + +/* 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 BUILD_THREAD (thread_info->private->ti.ti_tid, GET_PID (ptid)); +} + +static ptid_t +lwp_from_thread (ptid_t ptid) +{ + struct thread_info *thread_info; + ptid_t thread_ptid; + + if (!is_thread (ptid)) + return ptid; + + thread_info = find_thread_pid (ptid); + thread_db_get_info (thread_info); + + return BUILD_LWP (thread_info->private->ti.ti_lid, 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; + + td_thr_getfpregs_p = verbose_dlsym (handle, "td_thr_getfpregs"); + if (td_thr_getfpregs_p == NULL) + return 0; + + td_thr_getgregs_p = verbose_dlsym (handle, "td_thr_getgregs"); + if (td_thr_getgregs_p == NULL) + return 0; + + td_thr_setfpregs_p = verbose_dlsym (handle, "td_thr_setfpregs"); + if (td_thr_setfpregs_p == NULL) + return 0; + + td_thr_setgregs_p = verbose_dlsym (handle, "td_thr_setgregs"); + if (td_thr_setgregs_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. */ + (*bp) = gdbarch_convert_from_func_ptr_addr (current_gdbarch, + (CORE_ADDR) 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 + /* FIXME: kettenis/2000-04-23: The event reporting facility is + broken for TD_DEATH events in glibc 2.1.3, so don't enable it for + now. */ + 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 +} + +static void +thread_db_new_objfile (struct objfile *objfile) +{ + td_err_e err; + + /* 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. The real + problem here is that libthread_db is loaded too early - it should + only be loaded when there is a program to debug. */ + { + static int dejavu; + if (!dejavu) + { + Dl_info info; + const char *library = NULL; + /* Try dladdr. */ + 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; + printf_unfiltered ("Using host libthread_db library \"%s\".\n", + library); + dejavu = 1; + } + } + + /* Don't attempt to use thread_db on targets which can not run + (core files). */ + if (objfile == NULL || !target_has_execution) + { + /* All symbols have been discarded. If the thread_db target is + active, deactivate it now. */ + if (using_thread_db) + { + gdb_assert (proc_handle.pid == 0); + unpush_target (&thread_db_ops); + using_thread_db = 0; + } + + goto quit; + } + + if (using_thread_db) + /* Nothing to do. The thread library was already detected and the + target vector was already activated. */ + goto quit; + + /* Initialize the structure that identifies the child process. Note + that at this point there is no guarantee that we actually have a + 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; + } + +quit: + if (target_new_objfile_chain) + target_new_objfile_chain (objfile); +} + +/* 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 (); + + /* 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)); + + 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. */ +#ifdef ATTACH_LWP + ATTACH_LWP (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)), 0); +#endif + + /* 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 +thread_db_attach (char *args, int from_tty) +{ + target_beneath->to_attach (args, from_tty); + + /* Destroy thread info; it's no longer valid. */ + init_thread_list (); + + /* The child process is now the actual multi-threaded + program. Snatch its process ID... */ + proc_handle.pid = GET_PID (inferior_ptid); + + /* ...and perform the remaining initialization steps. */ + enable_thread_event_reporting (); + thread_db_find_new_threads (); +} + +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 supposed to be survive this function call. */ + inferior_ptid = lwp_from_thread (inferior_ptid); + + /* Forget about the child's process ID. We shouldn't need it + anymore. */ + proc_handle.pid = 0; + + target_beneath->to_detach (args, from_tty); +} + +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) - DECR_PC_AFTER_BREAK; + 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 = BUILD_THREAD (ti.ti_tid, GET_PID (ptid)); + + 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 (proc_handle.pid == 0) + /* The current child process isn't the actual multi-threaded + program yet, so don't try to do any special thread-specific + post-processing and bail out early. */ + return ptid; + + if (ourstatus->kind == TARGET_WAITKIND_EXITED) + return pid_to_ptid (-1); + + if (ourstatus->kind == TARGET_WAITKIND_STOPPED + && ourstatus->value.sig == TARGET_SIGNAL_TRAP) + /* Check for a thread event. */ + check_event (ptid); + + if (!ptid_equal (trap_ptid, null_ptid)) + trap_ptid = thread_from_lwp (trap_ptid); + + /* Change the ptid 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; + + return ptid; +} + +static int +thread_db_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write, + struct mem_attrib *attrib, struct target_ops *target) +{ + struct cleanup *old_chain = save_inferior_ptid (); + int xfer; + + if (is_thread (inferior_ptid)) + { + /* FIXME: This seems to be necessary to make sure breakpoints + are removed. */ + if (!target_thread_alive (inferior_ptid)) + inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid)); + else + inferior_ptid = lwp_from_thread (inferior_ptid); + } + + xfer = + target_beneath->deprecated_xfer_memory (memaddr, myaddr, len, write, + attrib, target); + + do_cleanups (old_chain); + return xfer; +} + +static void +thread_db_fetch_registers (int regno) +{ + struct thread_info *thread_info; + prgregset_t gregset; + gdb_prfpregset_t fpregset; + td_err_e err; + + if (!is_thread (inferior_ptid)) + { + /* Pass the request to the target beneath us. */ + target_beneath->to_fetch_registers (regno); + return; + } + + thread_info = find_thread_pid (inferior_ptid); + thread_db_map_id2thr (thread_info, 1); + + err = td_thr_getgregs_p (&thread_info->private->th, gregset); + if (err != TD_OK) + error ("Cannot fetch general-purpose registers for thread %ld: %s", + (long) GET_THREAD (inferior_ptid), thread_db_err_str (err)); + + err = td_thr_getfpregs_p (&thread_info->private->th, &fpregset); + if (err != TD_OK) + error ("Cannot get floating-point registers for thread %ld: %s", + (long) GET_THREAD (inferior_ptid), thread_db_err_str (err)); + + /* Note that we must call supply_gregset after calling the thread_db + routines because the thread_db routines call ps_lgetgregs and + friends which clobber GDB's register cache. */ + supply_gregset ((gdb_gregset_t *) gregset); + supply_fpregset (&fpregset); +} + +static void +thread_db_store_registers (int regno) +{ + prgregset_t gregset; + gdb_prfpregset_t fpregset; + td_err_e err; + struct thread_info *thread_info; + + if (!is_thread (inferior_ptid)) + { + /* Pass the request to the target beneath us. */ + target_beneath->to_store_registers (regno); + return; + } + + thread_info = find_thread_pid (inferior_ptid); + thread_db_map_id2thr (thread_info, 1); + + if (regno != -1) + { + char raw[MAX_REGISTER_SIZE]; + + deprecated_read_register_gen (regno, raw); + thread_db_fetch_registers (-1); + regcache_raw_supply (current_regcache, regno, raw); + } + + fill_gregset ((gdb_gregset_t *) gregset, -1); + fill_fpregset (&fpregset, -1); + + err = td_thr_setgregs_p (&thread_info->private->th, gregset); + if (err != TD_OK) + error ("Cannot store general-purpose registers for thread %ld: %s", + (long) GET_THREAD (inferior_ptid), thread_db_err_str (err)); + err = td_thr_setfpregs_p (&thread_info->private->th, &fpregset); + if (err != TD_OK) + error ("Cannot store floating-point registers for thread %ld: %s", + (long) GET_THREAD (inferior_ptid), thread_db_err_str (err)); +} + +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_create_inferior (char *exec_file, char *allargs, char **env, + int from_tty) +{ + unpush_target (&thread_db_ops); + using_thread_db = 0; + target_beneath->to_create_inferior (exec_file, allargs, env, from_tty); +} + +static void +thread_db_post_startup_inferior (ptid_t ptid) +{ + if (proc_handle.pid == 0) + { + /* The child process is now the actual multi-threaded + program. Snatch its process ID... */ + proc_handle.pid = GET_PID (ptid); + + /* ...and perform the remaining initialization steps. */ + enable_thread_event_reporting (); + thread_db_find_new_threads (); + } +} + +static void +thread_db_mourn_inferior (void) +{ + remove_thread_event_breakpoints (); + + /* Forget about the child's process ID. We shouldn't need it + anymore. */ + proc_handle.pid = 0; + + target_beneath->to_mourn_inferior (); + + /* Detach thread_db target ops. */ + unpush_target (&thread_db_ops); + using_thread_db = 0; +} + +static int +thread_db_thread_alive (ptid_t ptid) +{ + td_thrhandle_t th; + td_err_e err; + + if (is_thread (ptid)) + { + struct thread_info *thread_info; + thread_info = find_thread_pid (ptid); + + thread_db_map_id2thr (thread_info, 0); + if (!thread_info->private->th_valid) + return 0; + + err = td_thr_validate_p (&thread_info->private->th); + if (err != TD_OK) + return 0; + + if (!thread_info->private->ti_valid) + { + err = + td_thr_get_info_p (&thread_info->private->th, + &thread_info->private->ti); + if (err != TD_OK) + return 0; + thread_info->private->ti_valid = 1; + } + + if (thread_info->private->ti.ti_state == TD_THR_UNKNOWN + || thread_info->private->ti.ti_state == TD_THR_ZOMBIE) + return 0; /* A zombie thread. */ + + return 1; + } + + if (target_beneath->to_thread_alive) + return target_beneath->to_thread_alive (ptid); + + return 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 = BUILD_THREAD (ti.ti_tid, GET_PID (inferior_ptid)); + + 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]; + td_thrinfo_t *ti_p; + td_err_e err; + struct thread_info *thread_info; + + thread_info = find_thread_pid (ptid); + thread_db_map_id2thr (thread_info, 0); + if (!thread_info->private->th_valid) + { + snprintf (buf, sizeof (buf), "Thread %ld (Missing)", + GET_THREAD (ptid)); + return buf; + } + + ti_p = thread_db_get_info (thread_info); + + if (ti_p->ti_state == TD_THR_ACTIVE && ti_p->ti_lid != 0) + { + snprintf (buf, sizeof (buf), "Thread %ld (LWP %d)", + (long) ti_p->ti_tid, ti_p->ti_lid); + } + else + { + snprintf (buf, sizeof (buf), "Thread %ld (%s)", + (long) ti_p->ti_tid, + thread_db_state_str (ti_p->ti_state)); + } + + return buf; + } + + if (target_beneath->to_pid_to_str (ptid)) + return target_beneath->to_pid_to_str (ptid); + + return normal_pid_to_str (ptid); +} + +/* Get the address of the thread local variable in OBJFILE 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, struct objfile *objfile, + CORE_ADDR offset) +{ + if (is_thread (ptid)) + { + int objfile_is_library = (objfile->flags & OBJF_SHARED); + td_err_e err; + void *address; + CORE_ADDR lm; + struct thread_info *thread_info; + + /* glibc doesn't provide the needed interface. */ + if (!td_thr_tls_get_addr_p) + error ("Cannot find thread-local variables in this thread library."); + + /* Get the address of the link map for this objfile. */ + lm = svr4_fetch_objfile_link_map (objfile); + + /* Whoops, we couldn't find one. Bail out. */ + if (!lm) + { + if (objfile_is_library) + error ("Cannot find shared library `%s' link_map in dynamic" + " linker's module list", objfile->name); + else + error ("Cannot find executable file `%s' link_map in dynamic" + " linker's module list", objfile->name); + } + + /* Get info about the thread. */ + thread_info = find_thread_pid (ptid); + 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 *) 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. */ + if (objfile_is_library) + error ("The inferior has not yet allocated storage for" + " thread-local variables in\n" + "the shared library `%s'\n" + "for the thread %ld", + objfile->name, (long) GET_THREAD (ptid)); + else + error ("The inferior has not yet allocated storage for" + " thread-local variables in\n" + "the executable `%s'\n" + "for the thread %ld", + objfile->name, (long) GET_THREAD (ptid)); + } +#endif + + /* Something else went wrong. */ + if (err != TD_OK) + { + if (objfile_is_library) + error ("Cannot find thread-local storage for thread %ld, " + "shared library %s:\n%s", + (long) GET_THREAD (ptid), + objfile->name, thread_db_err_str (err)); + else + error ("Cannot find thread-local storage for thread %ld, " + "executable file %s:\n%s", + (long) GET_THREAD (ptid), + objfile->name, thread_db_err_str (err)); + } + + /* Cast assuming host == target. Joy. */ + return (CORE_ADDR) address; + } + + if (target_beneath->to_get_thread_local_address) + return target_beneath->to_get_thread_local_address (ptid, objfile, + offset); + + error ("Cannot find thread-local values 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_attach = thread_db_attach; + 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_fetch_registers = thread_db_fetch_registers; + thread_db_ops.to_store_registers = thread_db_store_registers; + thread_db_ops.deprecated_xfer_memory = thread_db_xfer_memory; + thread_db_ops.to_kill = thread_db_kill; + thread_db_ops.to_create_inferior = thread_db_create_inferior; + thread_db_ops.to_post_startup_inferior = thread_db_post_startup_inferior; + thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior; + thread_db_ops.to_thread_alive = thread_db_thread_alive; + 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_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. */ + target_new_objfile_chain = deprecated_target_new_objfile_hook; + deprecated_target_new_objfile_hook = thread_db_new_objfile; + } +} |