/* libthread_db assisted debugging support, generic parts.
- Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009
- Free Software Foundation, Inc.
+ Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+ 2010 Free Software Foundation, Inc.
This file is part of GDB.
static char *libthread_db_search_path;
+/* If non-zero, print details of libthread_db processing. */
+
+static int libthread_db_debug;
+
+static void
+show_libthread_db_debug (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file, _("libthread-db debugging is %s.\n"), value);
+}
+
+
/* If we're running on GNU/Linux, we must explicitly attach to any new
threads. */
td_event_e event, td_notify_t *ptr);
td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta,
td_thr_events_t *event);
+ td_err_e (*td_ta_clear_event_p) (const td_thragent_t *ta,
+ td_thr_events_t *event);
td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
td_event_msg_t *msg);
int event);
td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
- void *map_address,
- size_t offset, void **address);
+ psaddr_t map_address,
+ size_t offset, psaddr_t *address);
};
/* List of known processes using thread_db, and the required
struct thread_db_info *thread_db_list;
static void thread_db_find_new_threads_1 (ptid_t ptid);
+static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new);
/* Add the current inferior to the list of processes using libpthread.
Return a pointer to the newly allocated object that was added to
static struct thread_db_info *
add_thread_db_info (void *handle)
{
- int pid;
struct thread_db_info *info;
info = xcalloc (1, sizeof (*info));
info->pid = ptid_get_pid (inferior_ptid);
info->handle = handle;
- info->need_stale_parent_threads_check = 1;
+
+ /* The workaround works by reading from /proc/pid/status, so it is
+ disabled for core files. */
+ if (target_has_execution)
+ info->need_stale_parent_threads_check = 1;
info->next = thread_db_list;
thread_db_list = info;
}
/* Prototypes for local functions. */
-static void attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
- const td_thrinfo_t *ti_p);
+static int attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
+ const td_thrinfo_t *ti_p);
static void detach_thread (ptid_t ptid);
\f
have_threads_callback (struct thread_info *thread, void *args)
{
int pid = * (int *) args;
+
if (ptid_get_pid (thread->ptid) != pid)
return 0;
{
td_thrhandle_t th;
td_err_e err;
- ptid_t thread_ptid;
struct thread_db_info *info;
struct thread_get_info_inout io = {0};
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;
TRY_CATCH (except, RETURN_MASK_ERROR)
{
- thread_db_find_new_threads_1 (ptid);
+ thread_db_find_new_threads_2 (ptid, 1);
}
- if (except.reason < 0 && info_verbose)
- {
- exception_fprintf (gdb_stderr, except,
- "Warning: thread_db_find_new_threads_silently: ");
- }
+ if (except.reason < 0 && libthread_db_debug)
+ {
+ exception_fprintf (gdb_stderr, except,
+ "Warning: thread_db_find_new_threads_silently: ");
+ }
}
/* Lookup a library in which given symbol resides.
err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
if (err != TD_OK)
{
- if (info_verbose)
+ if (libthread_db_debug)
printf_unfiltered (_("td_ta_new failed: %s\n"),
thread_db_err_str (err));
else
/* These are not essential. */
info->td_ta_event_addr_p = dlsym (info->handle, "td_ta_event_addr");
info->td_ta_set_event_p = dlsym (info->handle, "td_ta_set_event");
+ info->td_ta_clear_event_p = dlsym (info->handle, "td_ta_clear_event");
info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg");
info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable");
info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr");
printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
- if (info_verbose || *libthread_db_search_path)
+ if (libthread_db_debug || *libthread_db_search_path)
{
const char *library;
if (thread_db_list->next == NULL)
push_target (&thread_db_ops);
- enable_thread_event_reporting ();
+ /* Enable event reporting, but not when debugging a core file. */
+ if (target_has_execution)
+ enable_thread_event_reporting ();
/* There appears to be a bug in glibc-2.3.6: calls to td_thr_get_info fail
with TD_ERR for statically linked executables if td_thr_get_info is
void *handle;
struct thread_db_info *info;
- if (info_verbose)
+ if (libthread_db_debug)
printf_unfiltered (_("Trying host libthread_db library: %s.\n"),
library);
handle = dlopen (library, RTLD_NOW);
if (handle == NULL)
{
- if (info_verbose)
+ if (libthread_db_debug)
printf_unfiltered (_("dlopen failed: %s.\n"), dlerror ());
return 0;
}
- if (info_verbose && strchr (library, '/') == NULL)
+ if (libthread_db_debug && strchr (library, '/') == NULL)
{
void *td_init;
while (*search_path)
{
const char *end = strchr (search_path, ':');
+
if (end)
{
size_t len = end - search_path;
+
if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path))
{
char *cp = xmalloc (len + 1);
+
memcpy (cp, search_path, len);
cp[len] = '\0';
warning (_("libthread_db_search_path component too long,"
if (info != NULL)
return 1;
- /* 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)
+ /* Don't attempt to use thread_db on executables not running
+ yet. */
+ if (!target_has_registers)
return 0;
/* Don't attempt to use thread_db for remote targets. */
- if (!target_can_run (¤t_target))
+ if (!(target_can_run (¤t_target) || core_bfd))
return 0;
if (thread_db_load_search ())
}
static void
-disable_thread_event_reporting (void)
+disable_thread_event_reporting (struct thread_db_info *info)
{
- td_thr_events_t events;
- struct thread_db_info *info;
-
- info = get_thread_db_info (GET_PID (inferior_ptid));
+ if (info->td_ta_clear_event_p != NULL)
+ {
+ td_thr_events_t events;
- /* Set the process wide mask saying we aren't interested in any
- events anymore. */
- td_event_emptyset (&events);
- info->td_ta_set_event_p (info->thread_agent, &events);
+ /* Set the process wide mask saying we aren't interested in any
+ events anymore. */
+ td_event_fillset (&events);
+ info->td_ta_clear_event_p (info->thread_agent, &events);
+ }
- /* Delete thread event breakpoints, if any. */
- remove_thread_event_breakpoints ();
info->td_create_bp_addr = 0;
info->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);
+ lin_thread_get_thread_signals (&mask);
sigemptyset (&thread_stop_set);
sigemptyset (&thread_print_set);
}
}
}
-#endif
}
/* Check whether thread_db is usable. This function is called when
void
check_for_thread_db (void)
{
- td_err_e err;
- static void *last_loaded;
-
/* Do nothing if we couldn't load libthread_db.so.1. */
if (!thread_db_load ())
return;
/* 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. */
+ that wasn't already in our list. Returns true on success. */
-static void
+static int
attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
const td_thrinfo_t *ti_p)
{
if (tp->private != NULL)
{
if (!tp->private->dying)
- return;
+ return 0;
delete_thread (ptid);
tp = NULL;
}
}
- check_thread_signals ();
+ if (target_has_execution)
+ 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. */
+ return 0; /* A zombie thread -- do not attach. */
/* Under GNU/Linux, we have to attach to each and every thread. */
- if (tp == NULL
+ if (target_has_execution
+ && tp == NULL
&& lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid))) < 0)
- return;
+ return 0;
/* Construct the thread's private data. */
private = xmalloc (sizeof (struct private_thread_info));
info = get_thread_db_info (GET_PID (ptid));
- /* Enable thread event reporting for this thread. */
- err = info->td_thr_event_enable_p (th_p, 1);
- if (err != TD_OK)
- error (_("Cannot enable thread event reporting for %s: %s"),
- target_pid_to_str (ptid), thread_db_err_str (err));
+ /* Enable thread event reporting for this thread, except when
+ debugging a core file. */
+ if (target_has_execution)
+ {
+ err = info->td_thr_event_enable_p (th_p, 1);
+ if (err != TD_OK)
+ error (_("Cannot enable thread event reporting for %s: %s"),
+ target_pid_to_str (ptid), thread_db_err_str (err));
+ }
+
+ return 1;
}
static void
if (info)
{
- disable_thread_event_reporting ();
-
- /* Delete the old thread event breakpoints. Note that unlike
- when mourning, we can remove them here because there's still
- a live inferior to poke at. In any case, GDB will not try to
- insert anything in the inferior when removing a
- breakpoint. */
- remove_thread_event_breakpoints ();
+ if (target_has_execution)
+ {
+ disable_thread_event_reporting (info);
+
+ /* Delete the old thread event breakpoints. Note that
+ unlike when mourning, we can remove them here because
+ there's still a live inferior to poke at. In any case,
+ GDB will not try to insert anything in the inferior when
+ removing a breakpoint. */
+ remove_thread_event_breakpoints ();
+ }
delete_thread_db_info (GET_PID (inferior_ptid));
}
unpush_target (ops);
}
+struct callback_data
+{
+ struct thread_db_info *info;
+ int new_threads;
+};
+
static int
find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
{
td_err_e err;
ptid_t ptid;
struct thread_info *tp;
- struct thread_db_info *info = data;
+ struct callback_data *cb_data = data;
+ struct thread_db_info *info = cb_data->info;
err = info->td_thr_get_info_p (th_p, &ti);
if (err != TD_OK)
if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
return 0; /* A zombie -- ignore. */
- if (ti.ti_tid == 0)
+ if (ti.ti_tid == 0 && target_has_execution)
{
/* A thread ID of zero means that this is the main thread, but
glibc has not yet initialized thread-local storage and the
if (info->need_stale_parent_threads_check)
{
int tgid = linux_proc_get_tgid (ti.ti_lid);
+
if (tgid != -1 && tgid != info->pid)
return 0;
}
ptid = ptid_build (info->pid, ti.ti_lid, 0);
tp = find_thread_ptid (ptid);
if (tp == NULL || tp->private == NULL)
- attach_thread (ptid, th_p, &ti);
+ {
+ if (attach_thread (ptid, th_p, &ti))
+ cb_data->new_threads += 1;
+ else
+ /* Problem attaching this thread; perhaps it exited before we
+ could attach it?
+ This could mean that the thread list inside glibc itself is in
+ inconsistent state, and libthread_db could go on looping forever
+ (observed with glibc-2.3.6). To prevent that, terminate
+ iteration: thread_db_find_new_threads_2 will retry. */
+ return 1;
+ }
return 0;
}
+/* Helper for thread_db_find_new_threads_2.
+ Returns number of new threads found. */
+
+static int
+find_new_threads_once (struct thread_db_info *info, int iteration,
+ td_err_e *errp)
+{
+ volatile struct gdb_exception except;
+ struct callback_data data;
+ td_err_e err = TD_ERR;
+
+ data.info = info;
+ data.new_threads = 0;
+
+ TRY_CATCH (except, RETURN_MASK_ERROR)
+ {
+ /* Iterate over all user-space threads to discover new threads. */
+ err = info->td_ta_thr_iter_p (info->thread_agent,
+ find_new_threads_callback,
+ &data,
+ TD_THR_ANY_STATE,
+ TD_THR_LOWEST_PRIORITY,
+ TD_SIGNO_MASK,
+ TD_THR_ANY_USER_FLAGS);
+ }
+
+ if (libthread_db_debug)
+ {
+ if (except.reason < 0)
+ exception_fprintf (gdb_stderr, except,
+ "Warning: find_new_threads_once: ");
+
+ printf_filtered (_("Found %d new threads in iteration %d.\n"),
+ data.new_threads, iteration);
+ }
+
+ if (errp != NULL)
+ *errp = err;
+
+ return data.new_threads;
+}
+
/* Search for new threads, accessing memory through stopped thread
- PTID. */
+ PTID. If UNTIL_NO_NEW is true, repeat searching until several
+ searches in a row do not discover any new threads. */
static void
-thread_db_find_new_threads_1 (ptid_t ptid)
+thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new)
{
td_err_e err;
- struct lwp_info *lp;
struct thread_db_info *info;
int pid = ptid_get_pid (ptid);
+ int i, loop;
- /* In linux, we can only read memory through a stopped lwp. */
- ALL_LWPS (lp, ptid)
- if (lp->stopped && ptid_get_pid (lp->ptid) == pid)
- break;
+ if (target_has_execution)
+ {
+ struct lwp_info *lp;
- if (!lp)
- /* There is no stopped thread. Bail out. */
- return;
+ /* In linux, we can only read memory through a stopped lwp. */
+ ALL_LWPS (lp, ptid)
+ if (lp->stopped && ptid_get_pid (lp->ptid) == pid)
+ break;
+
+ if (!lp)
+ /* There is no stopped thread. Bail out. */
+ return;
+ }
info = get_thread_db_info (GET_PID (ptid));
/* Access an lwp we know is stopped. */
info->proc_handle.ptid = ptid;
- /* Iterate over all user-space threads to discover new threads. */
- err = info->td_ta_thr_iter_p (info->thread_agent, find_new_threads_callback,
- info, 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));
+
+ if (until_no_new)
+ {
+ /* Require 4 successive iterations which do not find any new threads.
+ The 4 is a heuristic: there is an inherent race here, and I have
+ seen that 2 iterations in a row are not always sufficient to
+ "capture" all threads. */
+ for (i = 0, loop = 0; loop < 4; ++i, ++loop)
+ if (find_new_threads_once (info, i, NULL) != 0)
+ /* Found some new threads. Restart the loop from beginning. */
+ loop = -1;
+ }
+ else
+ {
+ find_new_threads_once (info, 0, &err);
+ if (err != TD_OK)
+ error (_("Cannot find new threads: %s"), thread_db_err_str (err));
+ }
+}
+
+static void
+thread_db_find_new_threads_1 (ptid_t ptid)
+{
+ thread_db_find_new_threads_2 (ptid, 0);
+}
+
+static int
+update_thread_core (struct lwp_info *info, void *closure)
+{
+ info->core = linux_nat_core_of_thread_1 (info->ptid);
+ return 0;
}
static void
return;
thread_db_find_new_threads_1 (inferior_ptid);
+
+ if (target_has_execution)
+ iterate_over_lwps (minus_one_ptid /* iterate over all */,
+ update_thread_core, NULL);
}
static char *
if (thread_info != NULL && thread_info->private != NULL)
{
td_err_e err;
- void *address;
+ psaddr_t address;
struct thread_db_info *info;
info = get_thread_db_info (GET_PID (ptid));
gdb_assert (lm != 0);
/* Finally, get the address of the variable. */
+ /* Note the cast through uintptr_t: this interface only works if
+ a target address fits in a psaddr_t, which is a host pointer.
+ So a 32-bit debugger can not access 64-bit TLS through this. */
err = info->td_thr_tls_get_addr_p (&thread_info->private->th,
- (void *)(size_t) lm,
+ (psaddr_t)(uintptr_t) lm,
offset, &address);
#ifdef THREAD_DB_HAS_TD_NOTALLOC
NULL,
NULL,
&setlist, &showlist);
+
+ add_setshow_zinteger_cmd ("libthread-db", class_maintenance,
+ &libthread_db_debug, _("\
+Set libthread-db debugging."), _("\
+Show libthread-db debugging."), _("\
+When non-zero, libthread-db debugging is enabled."),
+ NULL,
+ show_libthread_db_debug,
+ &setdebuglist, &showdebuglist);
+
/* Add ourselves to objfile event chain. */
observer_attach_new_objfile (thread_db_new_objfile);
}
projects / deliverable / binutils-gdb.git / blobdiff