/* Thread management interface, for the remote server for GDB.
- Copyright 2002
- Free Software Foundation, Inc.
+ Copyright (C) 2002-2019 Free Software Foundation, Inc.
Contributed by MontaVista Software.
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
+ 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,
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "server.h"
#include "linux-low.h"
-extern int debug_threads;
+#include "debug.h"
+#include "gdb_proc_service.h"
+#include "nat/gdb_thread_db.h"
+#include "gdbsupport/gdb_vecs.h"
+#include "nat/linux-procfs.h"
+#include "gdbsupport/scoped_restore.h"
-#ifdef HAVE_THREAD_DB_H
-#include <thread_db.h>
+#ifndef USE_LIBTHREAD_DB_DIRECTLY
+#include <dlfcn.h>
#endif
+#include <limits.h>
+#include <ctype.h>
-/* Correct for all GNU/Linux targets (for quite some time). */
-#define GDB_GREGSET_T elf_gregset_t
-#define GDB_FPREGSET_T elf_fpregset_t
+struct thread_db
+{
+ /* Structure that identifies the child process for the
+ <proc_service.h> interface. */
+ struct ps_prochandle proc_handle;
-#ifndef HAVE_ELF_FPREGSET_T
-/* Make sure we have said types. Not all platforms bring in <linux/elf.h>
- via <sys/procfs.h>. */
-#ifdef HAVE_LINUX_ELF_H
-#include <linux/elf.h>
-#endif
-#endif
+ /* Connection to the libthread_db library. */
+ td_thragent_t *thread_agent;
+
+ /* If this flag has been set, we've already asked GDB for all
+ symbols we might need; assume symbol cache misses are
+ failures. */
+ int all_symbols_looked_up;
-#include "../gdb_proc_service.h"
+#ifndef USE_LIBTHREAD_DB_DIRECTLY
+ /* Handle of the libthread_db from dlopen. */
+ void *handle;
+#endif
-/* Structure that identifies the child process for the
- <proc_service.h> interface. */
-static struct ps_prochandle proc_handle;
+ /* Addresses of libthread_db functions. */
+ td_ta_new_ftype *td_ta_new_p;
+ td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p;
+ td_thr_get_info_ftype *td_thr_get_info_p;
+ td_ta_thr_iter_ftype *td_ta_thr_iter_p;
+ td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p;
+ td_thr_tlsbase_ftype *td_thr_tlsbase_p;
+ td_symbol_list_ftype *td_symbol_list_p;
+};
-/* Connection to the libthread_db library. */
-static td_thragent_t *thread_agent;
+static char *libthread_db_search_path;
+static int find_one_thread (ptid_t);
static int find_new_threads_callback (const td_thrhandle_t *th_p, void *data);
-static char *
+static const char *
thread_db_err_str (td_err_e err)
{
static char buf[64];
return "only part of register set was written/read";
case TD_NOXREGS:
return "X register set not available for this thread";
+#ifdef HAVE_TD_VERSION
+ case TD_VERSION:
+ return "version mismatch between libthread_db and libpthread";
+#endif
default:
- snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
+ xsnprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
return buf;
}
}
case TD_THR_STOPPED_ASLEEP:
return "stopped by debugger AND blocked";
default:
- snprintf (buf, sizeof (buf), "unknown thread_db state %d", state);
+ xsnprintf (buf, sizeof (buf), "unknown thread_db state %d", state);
return buf;
}
}
#endif
-static void
-thread_db_create_event (CORE_ADDR where)
+/* Get thread info about PTID, accessing memory via the current
+ thread. */
+
+static int
+find_one_thread (ptid_t ptid)
{
- td_event_msg_t msg;
+ td_thrhandle_t th;
+ td_thrinfo_t ti;
td_err_e err;
- struct inferior_linux_data *tdata;
+ struct lwp_info *lwp;
+ struct thread_db *thread_db = current_process ()->priv->thread_db;
+ int lwpid = ptid.lwp ();
- if (debug_threads)
- fprintf (stderr, "Thread creation event.\n");
+ thread_info *thread = find_thread_ptid (ptid);
+ lwp = get_thread_lwp (thread);
+ if (lwp->thread_known)
+ return 1;
- tdata = inferior_target_data (current_inferior);
+ /* Get information about this thread. */
+ err = thread_db->td_ta_map_lwp2thr_p (thread_db->thread_agent, lwpid, &th);
+ if (err != TD_OK)
+ error ("Cannot get thread handle for LWP %d: %s",
+ lwpid, thread_db_err_str (err));
- /* FIXME: This assumes we don't get another event.
- In the LinuxThreads implementation, this is safe,
- because all events come from the manager thread
- (except for its own creation, of course). */
- err = td_ta_event_getmsg (thread_agent, &msg);
+ err = thread_db->td_thr_get_info_p (&th, &ti);
if (err != TD_OK)
- fprintf (stderr, "thread getmsg err: %s\n",
- thread_db_err_str (err));
+ error ("Cannot get thread info for LWP %d: %s",
+ lwpid, thread_db_err_str (err));
+
+ if (debug_threads)
+ debug_printf ("Found thread %ld (LWP %d)\n",
+ (unsigned long) ti.ti_tid, ti.ti_lid);
+
+ if (lwpid != ti.ti_lid)
+ {
+ warning ("PID mismatch! Expected %ld, got %ld",
+ (long) lwpid, (long) ti.ti_lid);
+ return 0;
+ }
+
+ /* If the new thread ID is zero, a final thread ID will be available
+ later. Do not enable thread debugging yet. */
+ if (ti.ti_tid == 0)
+ return 0;
- /* msg.event == TD_EVENT_CREATE */
+ lwp->thread_known = 1;
+ lwp->th = th;
+ lwp->thread_handle = ti.ti_tid;
- find_new_threads_callback (msg.th_p, NULL);
+ return 1;
}
-#if 0
-static void
-thread_db_death_event (CORE_ADDR where)
+/* Attach a thread. Return true on success. */
+
+static int
+attach_thread (const td_thrhandle_t *th_p, td_thrinfo_t *ti_p)
{
+ struct process_info *proc = current_process ();
+ int pid = pid_of (proc);
+ ptid_t ptid = ptid_t (pid, ti_p->ti_lid, 0);
+ struct lwp_info *lwp;
+ int err;
+
if (debug_threads)
- fprintf (stderr, "Thread death event.\n");
+ debug_printf ("Attaching to thread %ld (LWP %d)\n",
+ (unsigned long) ti_p->ti_tid, ti_p->ti_lid);
+ err = linux_attach_lwp (ptid);
+ if (err != 0)
+ {
+ std::string reason = linux_ptrace_attach_fail_reason_string (ptid, err);
+
+ warning ("Could not attach to thread %ld (LWP %d): %s",
+ (unsigned long) ti_p->ti_tid, ti_p->ti_lid, reason.c_str ());
+
+ return 0;
+ }
+
+ lwp = find_lwp_pid (ptid);
+ gdb_assert (lwp != NULL);
+ lwp->thread_known = 1;
+ lwp->th = *th_p;
+ lwp->thread_handle = ti_p->ti_tid;
+
+ return 1;
}
-#endif
+
+/* Attach thread if we haven't seen it yet.
+ Increment *COUNTER if we have attached a new thread.
+ Return false on failure. */
static int
-thread_db_enable_reporting ()
+maybe_attach_thread (const td_thrhandle_t *th_p, td_thrinfo_t *ti_p,
+ int *counter)
{
- td_thr_events_t events;
- td_notify_t notify;
- td_err_e err;
+ struct lwp_info *lwp;
- /* Set the process wide mask saying which events we're interested in. */
- td_event_emptyset (&events);
- td_event_addset (&events, TD_CREATE);
+ lwp = find_lwp_pid (ptid_t (ti_p->ti_lid));
+ if (lwp != NULL)
+ return 1;
-#if 0
- /* This is reported to be broken in glibc 2.1.3. A different approach
- will be necessary to support that. */
- td_event_addset (&events, TD_DEATH);
-#endif
+ if (!attach_thread (th_p, ti_p))
+ return 0;
+
+ if (counter != NULL)
+ *counter += 1;
+
+ return 1;
+}
+
+static int
+find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
+{
+ td_thrinfo_t ti;
+ td_err_e err;
+ struct thread_db *thread_db = current_process ()->priv->thread_db;
- err = td_ta_set_event (thread_agent, &events);
+ err = thread_db->td_thr_get_info_p (th_p, &ti);
if (err != TD_OK)
+ error ("Cannot get thread info: %s", thread_db_err_str (err));
+
+ if (ti.ti_lid == -1)
{
- warning ("Unable to set global thread event mask: %s",
- thread_db_err_str (err));
+ /* A thread with kernel thread ID -1 is either a thread that
+ exited and was joined, or a thread that is being created but
+ hasn't started yet, and that is reusing the tcb/stack of a
+ thread that previously exited and was joined. (glibc marks
+ terminated and joined threads with kernel thread ID -1. See
+ glibc PR17707. */
+ if (debug_threads)
+ debug_printf ("thread_db: skipping exited and "
+ "joined thread (0x%lx)\n",
+ (unsigned long) ti.ti_tid);
return 0;
}
- /* Get address for thread creation breakpoint. */
- err = td_ta_event_addr (thread_agent, TD_CREATE, ¬ify);
+ /* Check for zombies. */
+ if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
+ return 0;
+
+ if (!maybe_attach_thread (th_p, &ti, (int *) data))
+ {
+ /* Terminate iteration early: we might be looking at stale data in
+ the inferior. The thread_db_find_new_threads will retry. */
+ return 1;
+ }
+
+ return 0;
+}
+
+static void
+thread_db_find_new_threads (void)
+{
+ td_err_e err;
+ ptid_t ptid = current_ptid;
+ struct thread_db *thread_db = current_process ()->priv->thread_db;
+ int loop, iteration;
+
+ /* This function is only called when we first initialize thread_db.
+ First locate the initial thread. If it is not ready for
+ debugging yet, then stop. */
+ if (find_one_thread (ptid) == 0)
+ return;
+
+ /* 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 (loop = 0, iteration = 0; loop < 4; ++loop, ++iteration)
+ {
+ int new_thread_count = 0;
+
+ /* Iterate over all user-space threads to discover new threads. */
+ err = thread_db->td_ta_thr_iter_p (thread_db->thread_agent,
+ find_new_threads_callback,
+ &new_thread_count,
+ TD_THR_ANY_STATE,
+ TD_THR_LOWEST_PRIORITY,
+ TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
+ if (debug_threads)
+ debug_printf ("Found %d threads in iteration %d.\n",
+ new_thread_count, iteration);
+
+ if (new_thread_count != 0)
+ {
+ /* Found new threads. Restart iteration from beginning. */
+ loop = -1;
+ }
+ }
if (err != TD_OK)
+ error ("Cannot find new threads: %s", thread_db_err_str (err));
+}
+
+/* Cache all future symbols that thread_db might request. We can not
+ request symbols at arbitrary states in the remote protocol, only
+ when the client tells us that new symbols are available. So when
+ we load the thread library, make sure to check the entire list. */
+
+static void
+thread_db_look_up_symbols (void)
+{
+ struct thread_db *thread_db = current_process ()->priv->thread_db;
+ const char **sym_list;
+ CORE_ADDR unused;
+
+ for (sym_list = thread_db->td_symbol_list_p (); *sym_list; sym_list++)
+ look_up_one_symbol (*sym_list, &unused, 1);
+
+ /* We're not interested in any other libraries loaded after this
+ point, only in symbols in libpthread.so. */
+ thread_db->all_symbols_looked_up = 1;
+}
+
+int
+thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp)
+{
+ struct thread_db *thread_db = current_process ()->priv->thread_db;
+ int may_ask_gdb = !thread_db->all_symbols_looked_up;
+
+ /* If we've passed the call to thread_db_look_up_symbols, then
+ anything not in the cache must not exist; we're not interested
+ in any libraries loaded after that point, only in symbols in
+ libpthread.so. It might not be an appropriate time to look
+ up a symbol, e.g. while we're trying to fetch registers. */
+ return look_up_one_symbol (name, addrp, may_ask_gdb);
+}
+
+int
+thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
+ CORE_ADDR load_module, CORE_ADDR *address)
+{
+ psaddr_t addr;
+ td_err_e err;
+ struct lwp_info *lwp;
+ struct thread_info *saved_thread;
+ struct process_info *proc;
+ struct thread_db *thread_db;
+
+ proc = get_thread_process (thread);
+ thread_db = proc->priv->thread_db;
+
+ /* If the thread layer is not (yet) initialized, fail. */
+ if (thread_db == NULL || !thread_db->all_symbols_looked_up)
+ return TD_ERR;
+
+ /* If td_thr_tls_get_addr is missing rather do not expect td_thr_tlsbase
+ could work. */
+ if (thread_db->td_thr_tls_get_addr_p == NULL
+ || (load_module == 0 && thread_db->td_thr_tlsbase_p == NULL))
+ return -1;
+
+ lwp = get_thread_lwp (thread);
+ if (!lwp->thread_known)
+ find_one_thread (thread->id);
+ if (!lwp->thread_known)
+ return TD_NOTHR;
+
+ saved_thread = current_thread;
+ current_thread = thread;
+
+ if (load_module != 0)
+ {
+ /* 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 = thread_db->td_thr_tls_get_addr_p (&lwp->th,
+ (psaddr_t) (uintptr_t) load_module,
+ offset, &addr);
+ }
+ else
+ {
+ /* This code path handles the case of -static -pthread executables:
+ https://sourceware.org/ml/libc-help/2014-03/msg00024.html
+ For older GNU libc r_debug.r_map is NULL. For GNU libc after
+ PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
+ The constant number 1 depends on GNU __libc_setup_tls
+ initialization of l_tls_modid to 1. */
+ err = thread_db->td_thr_tlsbase_p (&lwp->th, 1, &addr);
+ addr = (char *) addr + offset;
+ }
+
+ current_thread = saved_thread;
+ if (err == TD_OK)
{
- warning ("Unable to get location for thread creation breakpoint: %s",
- thread_db_err_str (err));
+ *address = (CORE_ADDR) (uintptr_t) addr;
return 0;
}
- set_breakpoint_at ((CORE_ADDR) (unsigned long) notify.u.bptaddr,
- thread_db_create_event);
+ else
+ return err;
+}
-#if 0
- /* Don't concern ourselves with reported thread deaths, only
- with actual thread deaths (via wait). */
+/* See linux-low.h. */
+
+bool
+thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len)
+{
+ struct thread_db *thread_db;
+ struct lwp_info *lwp;
+ thread_info *thread = find_thread_ptid (ptid);
+
+ if (thread == NULL)
+ return false;
+
+ thread_db = get_thread_process (thread)->priv->thread_db;
+
+ if (thread_db == NULL)
+ return false;
+
+ lwp = get_thread_lwp (thread);
+
+ if (!lwp->thread_known && !find_one_thread (thread->id))
+ return false;
+
+ gdb_assert (lwp->thread_known);
+
+ *handle = (gdb_byte *) &lwp->thread_handle;
+ *handle_len = sizeof (lwp->thread_handle);
+ return true;
+}
+
+#ifdef USE_LIBTHREAD_DB_DIRECTLY
+
+static int
+thread_db_load_search (void)
+{
+ td_err_e err;
+ struct thread_db *tdb;
+ struct process_info *proc = current_process ();
+
+ gdb_assert (proc->priv->thread_db == NULL);
+
+ tdb = XCNEW (struct thread_db);
+ proc->priv->thread_db = tdb;
- /* Get address for thread death breakpoint. */
- err = td_ta_event_addr (thread_agent, TD_DEATH, ¬ify);
+ tdb->td_ta_new_p = &td_ta_new;
+
+ /* Attempt to open a connection to the thread library. */
+ err = tdb->td_ta_new_p (&tdb->proc_handle, &tdb->thread_agent);
if (err != TD_OK)
{
- warning ("Unable to get location for thread death breakpoint: %s",
- thread_db_err_str (err));
- return;
+ if (debug_threads)
+ debug_printf ("td_ta_new(): %s\n", thread_db_err_str (err));
+ free (tdb);
+ proc->priv->thread_db = NULL;
+ return 0;
}
- set_breakpoint_at ((CORE_ADDR) (unsigned long) notify.u.bptaddr,
- thread_db_death_event);
-#endif
+
+ tdb->td_ta_map_lwp2thr_p = &td_ta_map_lwp2thr;
+ tdb->td_thr_get_info_p = &td_thr_get_info;
+ tdb->td_ta_thr_iter_p = &td_ta_thr_iter;
+ tdb->td_symbol_list_p = &td_symbol_list;
+
+ /* These are not essential. */
+ tdb->td_thr_tls_get_addr_p = &td_thr_tls_get_addr;
+ tdb->td_thr_tlsbase_p = &td_thr_tlsbase;
return 1;
}
-static void
-maybe_attach_thread (const td_thrhandle_t *th_p, td_thrinfo_t *ti_p)
+#else
+
+static int
+try_thread_db_load_1 (void *handle)
{
td_err_e err;
- struct thread_info *inferior;
- struct process_info *process;
+ struct thread_db *tdb;
+ struct process_info *proc = current_process ();
+
+ gdb_assert (proc->priv->thread_db == NULL);
+
+ tdb = XCNEW (struct thread_db);
+ proc->priv->thread_db = tdb;
+
+ tdb->handle = handle;
+
+ /* Initialize pointers to the dynamic library functions we will use.
+ Essential functions first. */
+
+#define CHK(required, a) \
+ do \
+ { \
+ if ((a) == NULL) \
+ { \
+ if (debug_threads) \
+ debug_printf ("dlsym: %s\n", dlerror ()); \
+ if (required) \
+ { \
+ free (tdb); \
+ proc->priv->thread_db = NULL; \
+ return 0; \
+ } \
+ } \
+ } \
+ while (0)
+
+#define TDB_DLSYM(tdb, func) \
+ tdb->func ## _p = (func ## _ftype *) dlsym (tdb->handle, #func)
+
+ CHK (1, TDB_DLSYM (tdb, td_ta_new));
+
+ /* Attempt to open a connection to the thread library. */
+ err = tdb->td_ta_new_p (&tdb->proc_handle, &tdb->thread_agent);
+ if (err != TD_OK)
+ {
+ if (debug_threads)
+ debug_printf ("td_ta_new(): %s\n", thread_db_err_str (err));
+ free (tdb);
+ proc->priv->thread_db = NULL;
+ return 0;
+ }
- /* If we are attaching to our first thread, things are a little
- different. */
- if (all_threads.head == all_threads.tail)
+ CHK (1, TDB_DLSYM (tdb, td_ta_map_lwp2thr));
+ CHK (1, TDB_DLSYM (tdb, td_thr_get_info));
+ CHK (1, TDB_DLSYM (tdb, td_ta_thr_iter));
+ CHK (1, TDB_DLSYM (tdb, td_symbol_list));
+
+ /* These are not essential. */
+ CHK (0, TDB_DLSYM (tdb, td_thr_tls_get_addr));
+ CHK (0, TDB_DLSYM (tdb, td_thr_tlsbase));
+
+#undef CHK
+#undef TDB_DLSYM
+
+ return 1;
+}
+
+#ifdef HAVE_DLADDR
+
+/* Lookup a library in which given symbol resides.
+ Note: this is looking in the GDBSERVER process, not in the inferior.
+ Returns library name, or NULL. */
+
+static const char *
+dladdr_to_soname (const void *addr)
+{
+ Dl_info info;
+
+ if (dladdr (addr, &info) != 0)
+ return info.dli_fname;
+ return NULL;
+}
+
+#endif
+
+static int
+try_thread_db_load (const char *library)
+{
+ void *handle;
+
+ if (debug_threads)
+ debug_printf ("Trying host libthread_db library: %s.\n",
+ library);
+ handle = dlopen (library, RTLD_NOW);
+ if (handle == NULL)
+ {
+ if (debug_threads)
+ debug_printf ("dlopen failed: %s.\n", dlerror ());
+ return 0;
+ }
+
+#ifdef HAVE_DLADDR
+ if (debug_threads && strchr (library, '/') == NULL)
{
- inferior = (struct thread_info *) all_threads.head;
- process = get_thread_process (inferior);
- if (process->thread_known == 0)
+ void *td_init;
+
+ td_init = dlsym (handle, "td_init");
+ if (td_init != NULL)
{
- /* Switch to indexing the threads list by TID. */
- change_inferior_id (&all_threads, ti_p->ti_tid);
- goto found;
+ const char *const libpath = dladdr_to_soname (td_init);
+
+ if (libpath != NULL)
+ debug_printf ("Host %s resolved to: %s.\n", library, libpath);
}
}
-
- inferior = (struct thread_info *) find_inferior_id (&all_threads,
- ti_p->ti_tid);
- if (inferior != NULL)
- return;
+#endif
- if (debug_threads)
- fprintf (stderr, "Attaching to thread %ld (LWP %d)\n",
- ti_p->ti_tid, ti_p->ti_lid);
- linux_attach_lwp (ti_p->ti_lid, ti_p->ti_tid);
- inferior = (struct thread_info *) find_inferior_id (&all_threads,
- ti_p->ti_tid);
- if (inferior == NULL)
+ if (try_thread_db_load_1 (handle))
+ return 1;
+
+ /* This library "refused" to work on current inferior. */
+ dlclose (handle);
+ return 0;
+}
+
+/* Handle $sdir in libthread-db-search-path.
+ Look for libthread_db in the system dirs, or wherever a plain
+ dlopen(file_without_path) will look.
+ The result is true for success. */
+
+static int
+try_thread_db_load_from_sdir (void)
+{
+ return try_thread_db_load (LIBTHREAD_DB_SO);
+}
+
+/* Try to load libthread_db from directory DIR of length DIR_LEN.
+ The result is true for success. */
+
+static int
+try_thread_db_load_from_dir (const char *dir, size_t dir_len)
+{
+ char path[PATH_MAX];
+
+ if (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path))
{
- warning ("Could not attach to thread %ld (LWP %d)\n",
- ti_p->ti_tid, ti_p->ti_lid);
- return;
+ char *cp = (char *) xmalloc (dir_len + 1);
+
+ memcpy (cp, dir, dir_len);
+ cp[dir_len] = '\0';
+ warning (_("libthread-db-search-path component too long,"
+ " ignored: %s."), cp);
+ free (cp);
+ return 0;
}
- process = inferior_target_data (inferior);
+ memcpy (path, dir, dir_len);
+ path[dir_len] = '/';
+ strcpy (path + dir_len + 1, LIBTHREAD_DB_SO);
+ return try_thread_db_load (path);
+}
+
+/* Search libthread_db_search_path for libthread_db which "agrees"
+ to work on current inferior.
+ The result is true for success. */
-found:
- new_thread_notify (ti_p->ti_tid);
+static int
+thread_db_load_search (void)
+{
+ int rc = 0;
- process->tid = ti_p->ti_tid;
- process->lwpid = ti_p->ti_lid;
+ if (libthread_db_search_path == NULL)
+ libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
- process->thread_known = 1;
- err = td_thr_event_enable (th_p, 1);
- if (err != TD_OK)
- error ("Cannot enable thread event reporting for %d: %s",
- ti_p->ti_lid, thread_db_err_str (err));
+ std::vector<gdb::unique_xmalloc_ptr<char>> dir_vec
+ = dirnames_to_char_ptr_vec (libthread_db_search_path);
+
+ for (const gdb::unique_xmalloc_ptr<char> &this_dir_up : dir_vec)
+ {
+ char *this_dir = this_dir_up.get ();
+ const int pdir_len = sizeof ("$pdir") - 1;
+ size_t this_dir_len;
+
+ this_dir_len = strlen (this_dir);
+
+ if (strncmp (this_dir, "$pdir", pdir_len) == 0
+ && (this_dir[pdir_len] == '\0'
+ || this_dir[pdir_len] == '/'))
+ {
+ /* We don't maintain a list of loaded libraries so we don't know
+ where libpthread lives. We *could* fetch the info, but we don't
+ do that yet. Ignore it. */
+ }
+ else if (strcmp (this_dir, "$sdir") == 0)
+ {
+ if (try_thread_db_load_from_sdir ())
+ {
+ rc = 1;
+ break;
+ }
+ }
+ else
+ {
+ if (try_thread_db_load_from_dir (this_dir, this_dir_len))
+ {
+ rc = 1;
+ break;
+ }
+ }
+ }
+
+ if (debug_threads)
+ debug_printf ("thread_db_load_search returning %d\n", rc);
+ return rc;
}
-static int
-find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
+#endif /* USE_LIBTHREAD_DB_DIRECTLY */
+
+int
+thread_db_init (void)
{
- td_thrinfo_t ti;
- td_err_e err;
+ struct process_info *proc = current_process ();
- err = td_thr_get_info (th_p, &ti);
- if (err != TD_OK)
- error ("Cannot get thread info: %s", thread_db_err_str (err));
+ /* FIXME drow/2004-10-16: This is the "overall process ID", which
+ GNU/Linux calls tgid, "thread group ID". When we support
+ attaching to threads, the original thread may not be the correct
+ thread. We would have to get the process ID from /proc for NPTL.
- /* Check for zombies. */
- if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
- return 0;
+ This isn't the only place in gdbserver that assumes that the first
+ process in the list is the thread group leader. */
- maybe_attach_thread (th_p, &ti);
+ if (thread_db_load_search ())
+ {
+ /* It's best to avoid td_ta_thr_iter if possible. That walks
+ data structures in the inferior's address space that may be
+ corrupted, or, if the target is running, the list may change
+ while we walk it. In the latter case, it's possible that a
+ thread exits just at the exact time that causes GDBserver to
+ get stuck in an infinite loop. As the kernel supports clone
+ events and /proc/PID/task/ exists, then we already know about
+ all threads in the process. When we need info out of
+ thread_db on a given thread (e.g., for TLS), we'll use
+ find_one_thread then. That uses thread_db entry points that
+ do not walk libpthread's thread list, so should be safe, as
+ well as more efficient. */
+ if (!linux_proc_task_list_dir_exists (pid_of (proc)))
+ thread_db_find_new_threads ();
+ thread_db_look_up_symbols ();
+ return 1;
+ }
return 0;
}
static void
-thread_db_find_new_threads (void)
+switch_to_process (struct process_info *proc)
{
- td_err_e err;
+ int pid = pid_of (proc);
- /* Iterate over all user-space threads to discover new threads. */
- err = td_ta_thr_iter (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));
+ current_thread = find_any_thread_of_pid (pid);
}
-int
-thread_db_init ()
+/* Disconnect from libthread_db and free resources. */
+
+static void
+disable_thread_event_reporting (struct process_info *proc)
{
- int err;
+ struct thread_db *thread_db = proc->priv->thread_db;
+ if (thread_db)
+ {
+ td_err_e (*td_ta_clear_event_p) (const td_thragent_t *ta,
+ td_thr_events_t *event);
+
+#ifndef USE_LIBTHREAD_DB_DIRECTLY
+ td_ta_clear_event_p
+ = (td_ta_clear_event_ftype *) dlsym (thread_db->handle,
+ "td_ta_clear_event");
+#else
+ td_ta_clear_event_p = &td_ta_clear_event;
+#endif
- proc_handle.pid = ((struct inferior_list_entry *)current_inferior)->id;
+ if (td_ta_clear_event_p != NULL)
+ {
+ struct thread_info *saved_thread = current_thread;
+ td_thr_events_t events;
- err = td_ta_new (&proc_handle, &thread_agent);
- switch (err)
+ switch_to_process (proc);
+
+ /* Set the process wide mask saying we aren't interested
+ in any events anymore. */
+ td_event_fillset (&events);
+ (*td_ta_clear_event_p) (thread_db->thread_agent, &events);
+
+ current_thread = saved_thread;
+ }
+ }
+}
+
+void
+thread_db_detach (struct process_info *proc)
+{
+ struct thread_db *thread_db = proc->priv->thread_db;
+
+ if (thread_db)
{
- case TD_NOLIBTHREAD:
- /* No thread library was detected. */
- return 0;
+ disable_thread_event_reporting (proc);
+ }
+}
- case TD_OK:
- /* The thread library was detected. */
+/* Disconnect from libthread_db and free resources. */
- if (thread_db_enable_reporting () == 0)
- return 0;
- thread_db_find_new_threads ();
- return 1;
+void
+thread_db_mourn (struct process_info *proc)
+{
+ struct thread_db *thread_db = proc->priv->thread_db;
+ if (thread_db)
+ {
+ td_ta_delete_ftype *td_ta_delete_p;
- default:
- warning ("error initializing thread_db library.");
+#ifndef USE_LIBTHREAD_DB_DIRECTLY
+ td_ta_delete_p = (td_ta_delete_ftype *) dlsym (thread_db->handle, "td_ta_delete");
+#else
+ td_ta_delete_p = &td_ta_delete;
+#endif
+
+ if (td_ta_delete_p != NULL)
+ (*td_ta_delete_p) (thread_db->thread_agent);
+
+#ifndef USE_LIBTHREAD_DB_DIRECTLY
+ dlclose (thread_db->handle);
+#endif /* USE_LIBTHREAD_DB_DIRECTLY */
+
+ free (thread_db);
+ proc->priv->thread_db = NULL;
+ }
+}
+
+/* Handle "set libthread-db-search-path" monitor command and return 1.
+ For any other command, return 0. */
+
+int
+thread_db_handle_monitor_command (char *mon)
+{
+ const char *cmd = "set libthread-db-search-path";
+ size_t cmd_len = strlen (cmd);
+
+ if (strncmp (mon, cmd, cmd_len) == 0
+ && (mon[cmd_len] == '\0'
+ || mon[cmd_len] == ' '))
+ {
+ const char *cp = mon + cmd_len;
+
+ if (libthread_db_search_path != NULL)
+ free (libthread_db_search_path);
+
+ /* Skip leading space (if any). */
+ while (isspace (*cp))
+ ++cp;
+
+ if (*cp == '\0')
+ cp = LIBTHREAD_DB_SEARCH_PATH;
+ libthread_db_search_path = xstrdup (cp);
+
+ monitor_output ("libthread-db-search-path set to `");
+ monitor_output (libthread_db_search_path);
+ monitor_output ("'\n");
+ return 1;
}
+ /* Tell server.c to perform default processing. */
return 0;
}
+
+/* See linux-low.h. */
+
+void
+thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid)
+{
+ process_info *parent_proc = get_thread_process (parent_thr);
+ struct thread_db *thread_db = parent_proc->priv->thread_db;
+
+ /* If the thread layer isn't initialized, return. It may just
+ be that the program uses clone, but does not use libthread_db. */
+ if (thread_db == NULL || !thread_db->all_symbols_looked_up)
+ return;
+
+ /* find_one_thread calls into libthread_db which accesses memory via
+ the current thread. Temporarily switch to a thread we know is
+ stopped. */
+ scoped_restore restore_current_thread
+ = make_scoped_restore (¤t_thread, parent_thr);
+
+ if (!find_one_thread (child_ptid))
+ warning ("Cannot find thread after clone.");
+}
projects / deliverable / binutils-gdb.git / blobdiff