darling-gdb/gdb/linux-thread-db.c
Pedro Alves 4c28f408df Non-stop linux native.
* linux-nat.c (linux_test_for_tracefork): Block events while we're
	here.
	(get_pending_status): Implement non-stop mode.
	(linux_nat_detach): Stop threads before detaching.
	(linux_nat_resume): In non-stop mode, always resume only a single
	PTID.
	(linux_handle_extended_wait): On a clone event, in non-stop mode,
	add new lwp to GDB's thread table, and mark as running, executing
	and stopped appropriately.
	(linux_nat_filter_event): Don't assume there are other running
	threads when a thread exits.
	(linux_nat_wait): Mark the main thread as running and executing.
	In non-stop mode, don't stop all lwps.
	(linux_nat_kill): Stop lwps before killing them.
	(linux_nat_thread_alive): Use signal 0 to detect if a thread is
	alive.
	(send_sigint_callback): New.
	(linux_nat_stop): New.
	(linux_nat_add_target): Set to_stop to linux_nat_stop.

	* linux-nat.h (thread_db_attach_lwp): Declare.

	* linux-thread-db.c (thread_get_info_callback): Check for new
	threads if we have none.
	(thread_from_lwp, enable_thread_event): Set proc_handle.pid to the
	stopped lwp.  Check for new threads if we have none.
	(thread_db_attach_lwp): New.
	(thread_db_init): Set proc_handle.pid to inferior_ptid.
	(check_event): Set proc_handle.pid to the stopped lwp.
	(thread_db_find_new_threads): Set proc_handle.pid to any stopped
	lwp available, bail out if there is none.

	* linux-fork.c (linux_fork_killall): Use SIGKILL instead of
	PTRACE_KILL.
2008-07-10 22:58:37 +00:00

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/* libthread_db assisted debugging support, generic parts.
Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008
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
/* GNU/Linux libthread_db support.
libthread_db is a library, provided along with libpthread.so, which
exposes the internals of the thread library to a debugger. It
allows GDB to find existing threads, new threads as they are
created, thread IDs (usually, the result of pthread_self), and
thread-local variables.
The libthread_db interface originates on Solaris, where it is
both more powerful and more complicated. This implementation
only works for LinuxThreads and NPTL, the two glibc threading
libraries. It assumes that each thread is permanently assigned
to a single light-weight process (LWP).
libthread_db-specific information is stored in the "private" field
of struct thread_info. When the field is NULL we do not yet have
information about the new thread; this could be temporary (created,
but the thread library's data structures do not reflect it yet)
or permanent (created using clone instead of pthread_create).
Process IDs managed by linux-thread-db.c match those used by
linux-nat.c: a common PID for all processes, an LWP ID for each
thread, and no TID. We save the TID in private. Keeping it out
of the ptid_t prevents thread IDs changing when libpthread is
loaded or unloaded. */
/* 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);
static void detach_thread (ptid_t ptid);
/* 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. */
td_thrhandle_t th;
thread_t tid;
};
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 thread->private != NULL;
}
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, 0);
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;
return TD_THR_ZOMBIE;
}
if (thread_info == NULL)
{
/* New thread. Attach to it now (why wait?). */
if (!have_threads ())
thread_db_find_new_threads ();
else
attach_thread (thread_ptid, thp, &ti);
thread_info = find_thread_pid (thread_ptid);
gdb_assert (thread_info != NULL);
}
if (infop != NULL)
*(struct thread_info **) infop = thread_info;
return 0;
}
/* 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;
/* 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. */
proc_handle.pid = GET_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 (ptid_get_tid (ptid) == 0);
return ptid;
}
/* 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. */
int
thread_db_attach_lwp (ptid_t ptid)
{
td_thrhandle_t th;
td_thrinfo_t ti;
td_err_e err;
if (!using_thread_db)
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. */
proc_handle.pid = GET_LWP (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 ())
thread_db_find_new_threads ();
err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &th);
if (err != TD_OK)
/* Cannot find user-level thread. */
return 0;
err = td_thr_get_info_p (&th, &ti);
if (err != TD_OK)
{
warning (_("Cannot get thread info: %s"), thread_db_err_str (err));
return 0;
}
attach_thread (ptid, &th, &ti);
return 1;
}
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;
/* Access an lwp we know is stopped. */
proc_handle.pid = GET_LWP (inferior_ptid);
/* Get the breakpoint address for thread EVENT. */
err = td_ta_event_addr_p (thread_agent, event, &notify);
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),
&current_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 (&current_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)
{
struct private_thread_info *private;
struct thread_info *tp = NULL;
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 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 (!tp->private->dying)
return;
delete_thread (ptid);
tp = NULL;
}
}
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 (tp == NULL
&& lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid))) < 0)
return;
/* 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)
tp = add_thread_with_info (ptid, private);
else
tp->private = private;
/* 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)
{
struct thread_info *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_pid (ptid);
gdb_assert (thread_info != NULL && thread_info->private != NULL);
thread_info->private->dying = 1;
}
static void
thread_db_detach (char *args, int from_tty)
{
disable_thread_event_reporting ();
target_beneath->to_detach (args, from_tty);
/* Should this be done by detach_command? */
target_mourn_inferior ();
}
/* 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;
/* 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 != td_create_bp_addr && stop_pc != td_death_bp_addr)
return;
/* Access an lwp we know is stopped. */
proc_handle.pid = GET_LWP (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 ())
thread_db_find_new_threads ();
/* 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, 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 (ptid_t ptid, struct target_waitstatus *ourstatus)
{
ptid = target_beneath->to_wait (ptid, ourstatus);
if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
return ptid;
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 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. */
ptid = thread_from_lwp (ptid);
if (GET_PID (ptid) == -1)
ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
}
return ptid;
}
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
thread_db_can_async_p (void)
{
return target_beneath->to_can_async_p ();
}
static int
thread_db_is_async_p (void)
{
return target_beneath->to_is_async_p ();
}
static void
thread_db_async (void (*callback) (enum inferior_event_type event_type,
void *context), void *context)
{
return target_beneath->to_async (callback, context);
}
static int
thread_db_async_mask (int mask)
{
return target_beneath->to_async_mask (mask);
}
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;
struct thread_info *tp;
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, 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. */
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;
}
tp = find_thread_pid (ptid);
if (tp == NULL || tp->private == NULL)
attach_thread (ptid, th_p, &ti);
return 0;
}
/* Search for new threads, accessing memory through stopped thread
PTID. */
static void
thread_db_find_new_threads (void)
{
td_err_e err;
struct lwp_info *lp;
ptid_t ptid;
/* In linux, we can only read memory through a stopped lwp. */
ALL_LWPS (lp, ptid)
if (lp->stopped)
break;
if (!lp)
/* There is no stopped thread. Bail out. */
return;
/* Access an lwp we know is stopped. */
proc_handle.pid = GET_LWP (ptid);
/* 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)
{
struct thread_info *thread_info = find_thread_pid (ptid);
if (thread_info != NULL && thread_info->private != NULL)
{
static char buf[64];
thread_t tid;
tid = thread_info->private->tid;
thread_info = find_thread_pid (ptid);
snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
tid, 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 == NULL)
return NULL;
if (info->private->dying)
return "Exiting";
return NULL;
}
/* 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)
{
struct thread_info *thread_info;
/* If we have not discovered any threads yet, check now. */
if (!have_threads ())
thread_db_find_new_threads ();
/* Find the matching thread. */
thread_info = find_thread_pid (ptid);
if (thread_info != NULL && thread_info->private != NULL)
{
td_err_e err;
void *address;
/* 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);
/* 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_wait = thread_db_wait;
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_can_async_p = thread_db_can_async_p;
thread_db_ops.to_is_async_p = thread_db_is_async_p;
thread_db_ops.to_async = thread_db_async;
thread_db_ops.to_async_mask = thread_db_async_mask;
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);
}
}