/* libthread_db assisted debugging support, generic parts.
- Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007
- Free Software Foundation, Inc.
+ Copyright (C) 1999-2020 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
+ 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., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA. */
+ 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 "nat/gdb_thread_db.h"
+#include "gdbsupport/gdb_vecs.h"
#include "bfd.h"
-#include "exceptions.h"
+#include "command.h"
+#include "gdbcmd.h"
#include "gdbthread.h"
#include "inferior.h"
+#include "infrun.h"
#include "symfile.h"
#include "objfiles.h"
#include "target.h"
#include "regcache.h"
+#include "solib.h"
#include "solib-svr4.h"
#include "gdbcore.h"
+#include "observable.h"
#include "linux-nat.h"
-
+#include "nat/linux-procfs.h"
+#include "nat/linux-ptrace.h"
+#include "nat/linux-osdata.h"
+#include "auto-load.h"
+#include "cli/cli-utils.h"
#include <signal.h>
+#include <ctype.h>
+#include "nat/linux-namespaces.h"
+#include <algorithm>
+#include "gdbsupport/pathstuff.h"
+#include "valprint.h"
+#include "cli/cli-style.h"
+
+/* 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 NPTL, the glibc threading library. It assumes that each thread
+ is permanently assigned to a single light-weight process (LWP). At
+ some point it also supported the older LinuxThreads library, but it
+ no longer does.
+
+ 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. */
+
+static const target_info thread_db_target_info = {
+ "multi-thread",
+ N_("multi-threaded child process."),
+ N_("Threads and pthreads support.")
+};
-#ifdef HAVE_GNU_LIBC_VERSION_H
-#include <gnu/libc-version.h>
-#endif
+class thread_db_target final : public target_ops
+{
+public:
+ const target_info &info () const override
+ { return thread_db_target_info; }
+
+ strata stratum () const override { return thread_stratum; }
+
+ void detach (inferior *, int) override;
+ ptid_t wait (ptid_t, struct target_waitstatus *, int) override;
+ void resume (ptid_t, int, enum gdb_signal) override;
+ void mourn_inferior () override;
+ void update_thread_list () override;
+ std::string pid_to_str (ptid_t) override;
+ CORE_ADDR get_thread_local_address (ptid_t ptid,
+ CORE_ADDR load_module_addr,
+ CORE_ADDR offset) override;
+ const char *extra_thread_info (struct thread_info *) override;
+ ptid_t get_ada_task_ptid (long lwp, long thread) override;
+
+ thread_info *thread_handle_to_thread_info (const gdb_byte *thread_handle,
+ int handle_len,
+ inferior *inf) override;
+ gdb::byte_vector thread_info_to_thread_handle (struct thread_info *) override;
+};
-#ifndef LIBTHREAD_DB_SO
-#define LIBTHREAD_DB_SO "libthread_db.so.1"
-#endif
+static char *libthread_db_search_path;
-/* If we're running on GNU/Linux, we must explicitly attach to any new
- threads. */
+/* Set to true if thread_db auto-loading is enabled
+ by the "set auto-load libthread-db" command. */
+static bool auto_load_thread_db = true;
-/* This module's target vector. */
-static struct target_ops thread_db_ops;
+/* Set to true if load-time libthread_db tests have been enabled
+ by the "maintenance set check-libthread-db" command. */
+static bool check_thread_db_on_load = false;
+
+/* "show" command for the auto_load_thread_db configuration variable. */
+
+static void
+show_auto_load_thread_db (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file, _("Auto-loading of inferior specific libthread_db "
+ "is %s.\n"),
+ value);
+}
+
+static void
+set_libthread_db_search_path (const char *ignored, int from_tty,
+ struct cmd_list_element *c)
+{
+ if (*libthread_db_search_path == '\0')
+ {
+ xfree (libthread_db_search_path);
+ libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
+ }
+}
+
+/* If non-zero, print details of libthread_db processing. */
-/* The target vector that we call for things this module can't handle. */
-static struct target_ops *target_beneath;
+static unsigned 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);
+}
-/* Pointer to the next function on the objfile event chain. */
-static void (*target_new_objfile_chain) (struct objfile * objfile);
+/* If we're running on GNU/Linux, we must explicitly attach to any new
+ threads. */
-/* Non-zero if we're using this module's target vector. */
-static int using_thread_db;
+/* This module's target vector. */
+static thread_db_target the_thread_db_target;
/* Non-zero if we have determined the signals used by the threads
library. */
static sigset_t thread_stop_set;
static sigset_t thread_print_set;
-/* Structure that identifies the child process for the
- <proc_service.h> interface. */
-static struct ps_prochandle proc_handle;
-
-/* Connection to the libthread_db library. */
-static td_thragent_t *thread_agent;
-
-/* Pointers to the libthread_db functions. */
-
-static td_err_e (*td_init_p) (void);
-
-static td_err_e (*td_ta_new_p) (struct ps_prochandle * ps,
- td_thragent_t **ta);
-static td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt,
- td_thrhandle_t *__th);
-static td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta,
- lwpid_t lwpid, td_thrhandle_t *th);
-static td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta,
- td_thr_iter_f *callback, void *cbdata_p,
- td_thr_state_e state, int ti_pri,
- sigset_t *ti_sigmask_p,
- unsigned int ti_user_flags);
-static td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta,
- td_event_e event, td_notify_t *ptr);
-static td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta,
- td_thr_events_t *event);
-static td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
- td_event_msg_t *msg);
-
-static td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th);
-static td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th,
- td_thrinfo_t *infop);
-static td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th,
- int event);
-
-static td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
- void *map_address,
- size_t offset, void **address);
-
-/* Location of the thread creation event breakpoint. The code at this
- location in the child process will be called by the pthread library
- whenever a new thread is created. By setting a special breakpoint
- at this location, GDB can detect when a new thread is created. We
- obtain this location via the td_ta_event_addr call. */
-static CORE_ADDR td_create_bp_addr;
-
-/* Location of the thread death event breakpoint. */
-static CORE_ADDR td_death_bp_addr;
-
-/* Prototypes for local functions. */
-static void thread_db_find_new_threads (void);
-static void attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
- const td_thrinfo_t *ti_p, int verbose);
-static void detach_thread (ptid_t ptid, int verbose);
-\f
+struct thread_db_info
+{
+ struct thread_db_info *next;
-/* Building process ids. */
+ /* The target this thread_db_info is bound to. */
+ process_stratum_target *process_target;
-#define GET_PID(ptid) ptid_get_pid (ptid)
-#define GET_LWP(ptid) ptid_get_lwp (ptid)
-#define GET_THREAD(ptid) ptid_get_tid (ptid)
+ /* Process id this object refers to. */
+ int pid;
-#define is_lwp(ptid) (GET_LWP (ptid) != 0)
-#define is_thread(ptid) (GET_THREAD (ptid) != 0)
+ /* Handle from dlopen for libthread_db.so. */
+ void *handle;
-#define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0)
-\f
+ /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
+ HANDLE. It may be NULL for system library. */
+ char *filename;
+
+ /* Structure that identifies the child process for the
+ <proc_service.h> interface. */
+ struct ps_prochandle proc_handle;
+
+ /* Connection to the libthread_db library. */
+ td_thragent_t *thread_agent;
+
+ /* True if we need to apply the workaround for glibc/BZ5983. When
+ we catch a PTRACE_O_TRACEFORK, and go query the child's thread
+ list, nptl_db returns the parent's threads in addition to the new
+ (single) child thread. If this flag is set, we do extra work to
+ be able to ignore such stale entries. */
+ int need_stale_parent_threads_check;
+
+ /* Pointers to the libthread_db functions. */
+
+ td_init_ftype *td_init_p;
+ td_ta_new_ftype *td_ta_new_p;
+ td_ta_delete_ftype *td_ta_delete_p;
+ td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p;
+ td_ta_thr_iter_ftype *td_ta_thr_iter_p;
+ td_thr_get_info_ftype *td_thr_get_info_p;
+ td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p;
+ td_thr_tlsbase_ftype *td_thr_tlsbase_p;
+};
+
+/* List of known processes using thread_db, and the required
+ bookkeeping. */
+struct thread_db_info *thread_db_list;
+
+static void thread_db_find_new_threads_1 (thread_info *stopped);
+static void thread_db_find_new_threads_2 (thread_info *stopped,
+ bool until_no_new);
+
+static void check_thread_signals (void);
+
+static struct thread_info *record_thread
+ (struct thread_db_info *info, struct thread_info *tp,
+ ptid_t ptid, const td_thrhandle_t *th_p, const td_thrinfo_t *ti_p);
+
+/* Add the current inferior to the list of processes using libpthread.
+ Return a pointer to the newly allocated object that was added to
+ THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
+ LIBTHREAD_DB_SO. */
+
+static struct thread_db_info *
+add_thread_db_info (void *handle)
+{
+ struct thread_db_info *info = XCNEW (struct thread_db_info);
+
+ info->process_target = current_inferior ()->process_target ();
+ info->pid = inferior_ptid.pid ();
+ info->handle = handle;
+
+ /* 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;
+
+ return info;
+}
+
+/* Return the thread_db_info object representing the bookkeeping
+ related to process PID, if any; NULL otherwise. */
+
+static struct thread_db_info *
+get_thread_db_info (process_stratum_target *targ, int pid)
+{
+ struct thread_db_info *info;
+
+ for (info = thread_db_list; info; info = info->next)
+ if (targ == info->process_target && pid == info->pid)
+ return info;
+
+ return NULL;
+}
+
+static const char *thread_db_err_str (td_err_e err);
+
+/* When PID has exited or has been detached, we no longer want to keep
+ track of it as using libpthread. Call this function to discard
+ thread_db related info related to PID. Note that this closes
+ LIBTHREAD_DB_SO's dlopen'ed handle. */
+
+static void
+delete_thread_db_info (process_stratum_target *targ, int pid)
+{
+ struct thread_db_info *info, *info_prev;
+
+ info_prev = NULL;
+
+ for (info = thread_db_list; info; info_prev = info, info = info->next)
+ if (targ == info->process_target && pid == info->pid)
+ break;
+
+ if (info == NULL)
+ return;
+
+ if (info->thread_agent != NULL && info->td_ta_delete_p != NULL)
+ {
+ td_err_e err = info->td_ta_delete_p (info->thread_agent);
+
+ if (err != TD_OK)
+ warning (_("Cannot deregister process %d from libthread_db: %s"),
+ pid, thread_db_err_str (err));
+ info->thread_agent = NULL;
+ }
+
+ if (info->handle != NULL)
+ dlclose (info->handle);
+
+ xfree (info->filename);
+
+ if (info_prev)
+ info_prev->next = info->next;
+ else
+ thread_db_list = info->next;
+
+ xfree (info);
+}
/* Use "struct private_thread_info" to cache thread state. This is
a substantial optimization. */
-struct private_thread_info
+struct thread_db_thread_info : public private_thread_info
{
/* Flag set when we see a TD_DEATH event for this thread. */
- unsigned int dying:1;
+ bool dying = false;
/* Cached thread state. */
- unsigned int th_valid:1;
- unsigned int ti_valid:1;
-
- td_thrhandle_t th;
- td_thrinfo_t ti;
+ td_thrhandle_t th {};
+ thread_t tid {};
};
-\f
-static char *
+static thread_db_thread_info *
+get_thread_db_thread_info (thread_info *thread)
+{
+ return static_cast<thread_db_thread_info *> (thread->priv.get ());
+}
+
+static const char *
thread_db_err_str (td_err_e err)
{
static char buf[64];
return buf;
}
}
-\f
-/* 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.
+/* Fetch the user-level thread id of PTID. STOPPED is a stopped
+ thread that we can use to access memory. */
- 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)
+static struct thread_info *
+thread_from_lwp (thread_info *stopped, ptid_t ptid)
{
+ td_thrhandle_t th;
td_thrinfo_t ti;
td_err_e err;
- struct thread_info *thread_info;
- ptid_t thread_ptid;
+ struct thread_db_info *info;
+ struct thread_info *tp;
+
+ /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
+ th.th_unique = 0;
+
+ /* This ptid comes from linux-nat.c, which should always fill in the
+ LWP. */
+ gdb_assert (ptid.lwp () != 0);
- err = td_thr_get_info_p (thp, &ti);
+ info = get_thread_db_info (stopped->inf->process_target (), ptid.pid ());
+
+ /* Access an lwp we know is stopped. */
+ info->proc_handle.thread = stopped;
+ err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid.lwp (),
+ &th);
+ if (err != TD_OK)
+ error (_("Cannot find user-level thread for LWP %ld: %s"),
+ ptid.lwp (), thread_db_err_str (err));
+
+ err = info->td_thr_get_info_p (&th, &ti);
if (err != TD_OK)
error (_("thread_get_info_callback: cannot get thread info: %s"),
thread_db_err_str (err));
/* Fill the cache. */
- thread_ptid = ptid_build (GET_PID (inferior_ptid), ti.ti_lid, ti.ti_tid);
- thread_info = find_thread_pid (thread_ptid);
+ tp = find_thread_ptid (stopped->inf->process_target (), ptid);
+ return record_thread (info, tp, ptid, &th, &ti);
+}
+\f
+
+/* See linux-nat.h. */
+
+int
+thread_db_notice_clone (ptid_t parent, ptid_t child)
+{
+ struct thread_db_info *info;
+
+ info = get_thread_db_info (linux_target, child.pid ());
- /* 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 (info == NULL)
+ return 0;
+
+ thread_info *stopped = find_thread_ptid (linux_target, parent);
+
+ thread_from_lwp (stopped, child);
+
+ /* If we do not know about the main thread's pthread info yet, this
+ would be a good time to find it. */
+ thread_from_lwp (stopped, parent);
+ return 1;
+}
+
+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;
+}
+
+/* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
+ return 1 if this version is lower (and not equal) to
+ VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
+
+static int
+inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min)
+{
+ struct bound_minimal_symbol version_msym;
+ CORE_ADDR version_addr;
+ int got, retval = 0;
+
+ version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL);
+ if (version_msym.minsym == NULL)
+ return 0;
+
+ version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym);
+ gdb::unique_xmalloc_ptr<char> version
+ = target_read_string (version_addr, 32, &got);
+ if (version != nullptr
+ && memchr (version.get (), 0, got) == version.get () + got - 1)
+ {
+ int major, minor;
+
+ retval = (sscanf (version.get (), "%d.%d", &major, &minor) == 2
+ && (major < ver_major_min
+ || (major == ver_major_min && minor < ver_minor_min)));
+ }
+
+ return retval;
+}
+
+/* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
+ if appropriate.
+
+ Return 1 if the caller should abort libthread_db initialization. Return 0
+ otherwise. */
+
+static int
+thread_db_find_new_threads_silently (thread_info *stopped)
+{
+
+ try
+ {
+ thread_db_find_new_threads_2 (stopped, true);
+ }
+
+ catch (const gdb_exception_error &except)
{
- if (infop != NULL)
- *(struct thread_info **) infop = thread_info;
- if (thread_info != NULL)
+ if (libthread_db_debug)
+ exception_fprintf (gdb_stdlog, except,
+ "Warning: thread_db_find_new_threads_silently: ");
+
+ /* There is a bug fixed between nptl 2.6.1 and 2.7 by
+ commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
+ where calls to td_thr_get_info fail with TD_ERR for statically linked
+ executables if td_thr_get_info is called before glibc has initialized
+ itself.
+
+ If the nptl bug is NOT present in the inferior and still thread_db
+ reports an error return 1. It means the inferior has corrupted thread
+ list and GDB should fall back only to LWPs.
+
+ If the nptl bug is present in the inferior return 0 to silently ignore
+ such errors, and let gdb enumerate threads again later. In such case
+ GDB cannot properly display LWPs if the inferior thread list is
+ corrupted. For core files it does not apply, no 'later enumeration'
+ is possible. */
+
+ if (!target_has_execution || !inferior_has_bug ("nptl_version", 2, 7))
{
- 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;
+ exception_fprintf (gdb_stderr, except,
+ _("Warning: couldn't activate thread debugging "
+ "using libthread_db: "));
+ return 1;
}
- return TD_THR_ZOMBIE;
}
- if (thread_info == NULL)
+ return 0;
+}
+
+/* Lookup a library in which given symbol resides.
+ Note: this is looking in GDB 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;
+}
+
+/* State for check_thread_db_callback. */
+
+struct check_thread_db_info
+{
+ /* The libthread_db under test. */
+ struct thread_db_info *info;
+
+ /* True if progress should be logged. */
+ bool log_progress;
+
+ /* True if the callback was called. */
+ bool threads_seen;
+
+ /* Name of last libthread_db function called. */
+ const char *last_call;
+
+ /* Value returned by last libthread_db call. */
+ td_err_e last_result;
+};
+
+static struct check_thread_db_info *tdb_testinfo;
+
+/* Callback for check_thread_db. */
+
+static int
+check_thread_db_callback (const td_thrhandle_t *th, void *arg)
+{
+ gdb_assert (tdb_testinfo != NULL);
+ tdb_testinfo->threads_seen = true;
+
+#define LOG(fmt, args...) \
+ do \
+ { \
+ if (tdb_testinfo->log_progress) \
+ { \
+ debug_printf (fmt, ## args); \
+ gdb_flush (gdb_stdlog); \
+ } \
+ } \
+ while (0)
+
+#define CHECK_1(expr, args...) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ LOG (" ... FAIL!\n"); \
+ error (args); \
+ } \
+ } \
+ while (0)
+
+#define CHECK(expr) \
+ CHECK_1 (expr, "(%s) == false", #expr)
+
+#define CALL_UNCHECKED(func, args...) \
+ do \
+ { \
+ tdb_testinfo->last_call = #func; \
+ tdb_testinfo->last_result \
+ = tdb_testinfo->info->func ## _p (args); \
+ } \
+ while (0)
+
+#define CHECK_CALL() \
+ CHECK_1 (tdb_testinfo->last_result == TD_OK, \
+ _("%s failed: %s"), \
+ tdb_testinfo->last_call, \
+ thread_db_err_str (tdb_testinfo->last_result)) \
+
+#define CALL(func, args...) \
+ do \
+ { \
+ CALL_UNCHECKED (func, args); \
+ CHECK_CALL (); \
+ } \
+ while (0)
+
+ LOG (" Got thread");
+
+ /* Check td_ta_thr_iter passed consistent arguments. */
+ CHECK (th != NULL);
+ CHECK (arg == (void *) tdb_testinfo);
+ CHECK (th->th_ta_p == tdb_testinfo->info->thread_agent);
+
+ LOG (" %s", core_addr_to_string_nz ((CORE_ADDR) th->th_unique));
+
+ /* Check td_thr_get_info. */
+ td_thrinfo_t ti;
+ CALL (td_thr_get_info, th, &ti);
+
+ LOG (" => %d", ti.ti_lid);
+
+ CHECK (ti.ti_ta_p == th->th_ta_p);
+ CHECK (ti.ti_tid == (thread_t) th->th_unique);
+
+ /* Check td_ta_map_lwp2thr. */
+ td_thrhandle_t th2;
+ memset (&th2, 23, sizeof (td_thrhandle_t));
+ CALL_UNCHECKED (td_ta_map_lwp2thr, th->th_ta_p, ti.ti_lid, &th2);
+
+ if (tdb_testinfo->last_result == TD_ERR && !target_has_execution)
+ {
+ /* Some platforms require execution for td_ta_map_lwp2thr. */
+ LOG (_("; can't map_lwp2thr"));
+ }
+ else
+ {
+ CHECK_CALL ();
+
+ LOG (" => %s", core_addr_to_string_nz ((CORE_ADDR) th2.th_unique));
+
+ CHECK (memcmp (th, &th2, sizeof (td_thrhandle_t)) == 0);
+ }
+
+ /* Attempt TLS access. Assuming errno is TLS, this calls
+ thread_db_get_thread_local_address, which in turn calls
+ td_thr_tls_get_addr for live inferiors or td_thr_tlsbase
+ for core files. This test is skipped if the thread has
+ not been recorded; proceeding in that case would result
+ in the test having the side-effect of noticing threads
+ which seems wrong.
+
+ Note that in glibc's libthread_db td_thr_tls_get_addr is
+ a thin wrapper around td_thr_tlsbase; this check always
+ hits the bulk of the code.
+
+ Note also that we don't actually check any libthread_db
+ calls are made, we just assume they were; future changes
+ to how GDB accesses TLS could result in this passing
+ without exercising the calls it's supposed to. */
+ ptid_t ptid = ptid_t (tdb_testinfo->info->pid, ti.ti_lid, 0);
+ thread_info *thread_info = find_thread_ptid (linux_target, ptid);
+ if (thread_info != NULL && thread_info->priv != 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);
+ LOG ("; errno");
+
+ scoped_restore_current_thread restore_current_thread;
+ switch_to_thread (thread_info);
+
+ expression_up expr = parse_expression ("(int) errno");
+ struct value *val = evaluate_expression (expr.get ());
+
+ if (tdb_testinfo->log_progress)
+ {
+ struct value_print_options opts;
+
+ get_user_print_options (&opts);
+ LOG (" = ");
+ value_print (val, gdb_stdlog, &opts);
+ }
}
- 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;
+ LOG (" ... OK\n");
- if (infop != NULL)
- *(struct thread_info **) infop = thread_info;
+#undef LOG
+#undef CHECK_1
+#undef CHECK
+#undef CALL_UNCHECKED
+#undef CHECK_CALL
+#undef CALL
return 0;
}
-/* Accessor functions for the thread_db information, with caching. */
+/* Run integrity checks on the dlopen()ed libthread_db described by
+ INFO. Returns true on success, displays a warning and returns
+ false on failure. Logs progress messages to gdb_stdlog during
+ the test if LOG_PROGRESS is true. */
-static void
-thread_db_map_id2thr (struct thread_info *thread_info, int fatal)
+static bool
+check_thread_db (struct thread_db_info *info, bool log_progress)
+{
+ bool test_passed = true;
+
+ if (log_progress)
+ debug_printf (_("Running libthread_db integrity checks:\n"));
+
+ /* GDB avoids using td_ta_thr_iter wherever possible (see comment
+ in try_thread_db_load_1 below) so in order to test it we may
+ have to locate it ourselves. */
+ td_ta_thr_iter_ftype *td_ta_thr_iter_p = info->td_ta_thr_iter_p;
+ if (td_ta_thr_iter_p == NULL)
+ {
+ void *thr_iter = verbose_dlsym (info->handle, "td_ta_thr_iter");
+ if (thr_iter == NULL)
+ return 0;
+
+ td_ta_thr_iter_p = (td_ta_thr_iter_ftype *) thr_iter;
+ }
+
+ /* Set up the test state we share with the callback. */
+ gdb_assert (tdb_testinfo == NULL);
+ struct check_thread_db_info tdb_testinfo_buf;
+ tdb_testinfo = &tdb_testinfo_buf;
+
+ memset (tdb_testinfo, 0, sizeof (struct check_thread_db_info));
+ tdb_testinfo->info = info;
+ tdb_testinfo->log_progress = log_progress;
+
+ /* td_ta_thr_iter shouldn't be used on running processes. Note that
+ it's possible the inferior will stop midway through modifying one
+ of its thread lists, in which case the check will spuriously
+ fail. */
+ linux_stop_and_wait_all_lwps ();
+
+ try
+ {
+ td_err_e err = td_ta_thr_iter_p (info->thread_agent,
+ check_thread_db_callback,
+ tdb_testinfo,
+ TD_THR_ANY_STATE,
+ TD_THR_LOWEST_PRIORITY,
+ TD_SIGNO_MASK,
+ TD_THR_ANY_USER_FLAGS);
+
+ if (err != TD_OK)
+ error (_("td_ta_thr_iter failed: %s"), thread_db_err_str (err));
+
+ if (!tdb_testinfo->threads_seen)
+ error (_("no threads seen"));
+ }
+ catch (const gdb_exception_error &except)
+ {
+ if (warning_pre_print)
+ fputs_unfiltered (warning_pre_print, gdb_stderr);
+
+ exception_fprintf (gdb_stderr, except,
+ _("libthread_db integrity checks failed: "));
+
+ test_passed = false;
+ }
+
+ if (test_passed && log_progress)
+ debug_printf (_("libthread_db integrity checks passed.\n"));
+
+ tdb_testinfo = NULL;
+
+ linux_unstop_all_lwps ();
+
+ return test_passed;
+}
+
+/* Attempt to initialize dlopen()ed libthread_db, described by INFO.
+ Return true on success.
+ Failure could happen if libthread_db does not have symbols we expect,
+ or when it refuses to work with the current inferior (e.g. due to
+ version mismatch between libthread_db and libpthread). */
+
+static bool
+try_thread_db_load_1 (struct thread_db_info *info)
{
td_err_e err;
- if (thread_info->private->th_valid)
- return;
+ /* Initialize pointers to the dynamic library functions we will use.
+ Essential functions first. */
+
+#define TDB_VERBOSE_DLSYM(info, func) \
+ info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
+
+#define TDB_DLSYM(info, func) \
+ info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
+
+#define CHK(a) \
+ do \
+ { \
+ if ((a) == NULL) \
+ return false; \
+ } while (0)
- err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (thread_info->ptid),
- &thread_info->private->th);
+ CHK (TDB_VERBOSE_DLSYM (info, td_init));
+
+ err = info->td_init_p ();
if (err != TD_OK)
{
- if (fatal)
- error (_("Cannot find thread %ld: %s"),
- (long) GET_THREAD (thread_info->ptid),
+ warning (_("Cannot initialize libthread_db: %s"),
thread_db_err_str (err));
+ return false;
+ }
+
+ CHK (TDB_VERBOSE_DLSYM (info, td_ta_new));
+
+ /* Initialize the structure that identifies the child process. */
+ info->proc_handle.thread = inferior_thread ();
+
+ /* Now attempt to open a connection to the thread library. */
+ err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
+ if (err != TD_OK)
+ {
+ if (libthread_db_debug)
+ fprintf_unfiltered (gdb_stdlog, _("td_ta_new failed: %s\n"),
+ thread_db_err_str (err));
+ else
+ switch (err)
+ {
+ case TD_NOLIBTHREAD:
+#ifdef THREAD_DB_HAS_TD_VERSION
+ case TD_VERSION:
+#endif
+ /* The errors above are not unexpected and silently ignored:
+ they just mean we haven't found correct version of
+ libthread_db yet. */
+ break;
+ default:
+ warning (_("td_ta_new failed: %s"), thread_db_err_str (err));
+ }
+ return false;
}
+
+ /* These are essential. */
+ CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr));
+ CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info));
+
+ /* These are not essential. */
+ TDB_DLSYM (info, td_thr_tls_get_addr);
+ TDB_DLSYM (info, td_thr_tlsbase);
+ TDB_DLSYM (info, td_ta_delete);
+
+ /* 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, may change while we walk them. If
+ there's execution (and /proc is mounted), then we're already
+ attached to all LWPs. Use thread_from_lwp, which uses
+ td_ta_map_lwp2thr instead, which does not walk the thread list.
+
+ td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
+ currently on core targets, as it uses ptrace directly. */
+ if (target_has_execution
+ && linux_proc_task_list_dir_exists (inferior_ptid.pid ()))
+ info->td_ta_thr_iter_p = NULL;
else
- thread_info->private->th_valid = 1;
+ CHK (TDB_VERBOSE_DLSYM (info, td_ta_thr_iter));
+
+#undef TDB_VERBOSE_DLSYM
+#undef TDB_DLSYM
+#undef CHK
+
+ /* Run integrity checks if requested. */
+ if (check_thread_db_on_load)
+ {
+ if (!check_thread_db (info, libthread_db_debug))
+ return false;
+ }
+
+ if (info->td_ta_thr_iter_p == NULL)
+ {
+ struct lwp_info *lp;
+ int pid = inferior_ptid.pid ();
+ thread_info *curr_thread = inferior_thread ();
+
+ linux_stop_and_wait_all_lwps ();
+
+ ALL_LWPS (lp)
+ if (lp->ptid.pid () == pid)
+ thread_from_lwp (curr_thread, lp->ptid);
+
+ linux_unstop_all_lwps ();
+ }
+ else if (thread_db_find_new_threads_silently (inferior_thread ()) != 0)
+ {
+ /* Even if libthread_db initializes, if the thread list is
+ corrupted, we'd not manage to list any threads. Better reject this
+ thread_db, and fall back to at least listing LWPs. */
+ return false;
+ }
+
+ printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
+
+ if (*libthread_db_search_path || libthread_db_debug)
+ {
+ struct ui_file *file;
+ const char *library;
+
+ library = dladdr_to_soname ((const void *) *info->td_ta_new_p);
+ if (library == NULL)
+ library = LIBTHREAD_DB_SO;
+
+ /* If we'd print this to gdb_stdout when debug output is
+ disabled, still print it to gdb_stdout if debug output is
+ enabled. User visible output should not depend on debug
+ settings. */
+ file = *libthread_db_search_path != '\0' ? gdb_stdout : gdb_stdlog;
+ fprintf_unfiltered (file,
+ _("Using host libthread_db library \"%ps\".\n"),
+ styled_string (file_name_style.style (), library));
+ }
+
+ /* The thread library was detected. Activate the thread_db target
+ for this process. */
+ push_target (&the_thread_db_target);
+ return true;
}
-\f
-/* Convert between user-level thread ids and LWP ids. */
-static ptid_t
-thread_from_lwp (ptid_t ptid)
+/* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
+ relative, or just LIBTHREAD_DB. */
+
+static bool
+try_thread_db_load (const char *library, bool check_auto_load_safe)
{
- td_thrhandle_t th;
- td_err_e err;
- struct thread_info *thread_info;
- ptid_t thread_ptid;
+ void *handle;
+ struct thread_db_info *info;
+
+ if (libthread_db_debug)
+ fprintf_unfiltered (gdb_stdlog,
+ _("Trying host libthread_db library: %s.\n"),
+ library);
- if (GET_LWP (ptid) == 0)
- ptid = BUILD_LWP (GET_PID (ptid), GET_PID (ptid));
+ if (check_auto_load_safe)
+ {
+ if (access (library, R_OK) != 0)
+ {
+ /* Do not print warnings by file_is_auto_load_safe if the library does
+ not exist at this place. */
+ if (libthread_db_debug)
+ fprintf_unfiltered (gdb_stdlog, _("open failed: %s.\n"),
+ safe_strerror (errno));
+ return false;
+ }
- gdb_assert (is_lwp (ptid));
+ if (!file_is_auto_load_safe (library, _("auto-load: Loading libthread-db "
+ "library \"%s\" from explicit "
+ "directory.\n"),
+ library))
+ return false;
+ }
- err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &th);
- if (err != TD_OK)
- error (_("Cannot find user-level thread for LWP %ld: %s"),
- GET_LWP (ptid), thread_db_err_str (err));
-
- thread_info = NULL;
-
- /* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the
- event thread has already died. If another gdb interface has called
- thread_alive() previously, the thread won't be found on the thread list
- anymore. In that case, we don't want to process this ptid anymore
- to avoid the possibility of later treating it as a newly
- discovered thread id that we should add to the list. Thus,
- we return a -1 ptid which is also how the thread list marks a
- dead thread. */
- if (thread_get_info_callback (&th, &thread_info) == TD_THR_ZOMBIE
- && thread_info == NULL)
- return pid_to_ptid (-1);
-
- gdb_assert (thread_info && thread_info->private->ti_valid);
-
- return ptid_build (GET_PID (ptid), GET_LWP (ptid),
- thread_info->private->ti.ti_tid);
+ handle = dlopen (library, RTLD_NOW);
+ if (handle == NULL)
+ {
+ if (libthread_db_debug)
+ fprintf_unfiltered (gdb_stdlog, _("dlopen failed: %s.\n"), dlerror ());
+ return false;
+ }
+
+ if (libthread_db_debug && strchr (library, '/') == NULL)
+ {
+ void *td_init;
+
+ td_init = dlsym (handle, "td_init");
+ if (td_init != NULL)
+ {
+ const char *const libpath = dladdr_to_soname (td_init);
+
+ if (libpath != NULL)
+ fprintf_unfiltered (gdb_stdlog, _("Host %s resolved to: %s.\n"),
+ library, libpath);
+ }
+ }
+
+ info = add_thread_db_info (handle);
+
+ /* Do not save system library name, that one is always trusted. */
+ if (strchr (library, '/') != NULL)
+ info->filename = gdb_realpath (library).release ();
+
+ if (try_thread_db_load_1 (info))
+ return true;
+
+ /* This library "refused" to work on current inferior. */
+ delete_thread_db_info (current_inferior ()->process_target (),
+ inferior_ptid.pid ());
+ return false;
}
-static ptid_t
-lwp_from_thread (ptid_t ptid)
+/* Subroutine of try_thread_db_load_from_pdir to simplify it.
+ Try loading libthread_db in directory(OBJ)/SUBDIR.
+ SUBDIR may be NULL. It may also be something like "../lib64".
+ The result is true for success. */
+
+static bool
+try_thread_db_load_from_pdir_1 (struct objfile *obj, const char *subdir)
{
- return BUILD_LWP (GET_LWP (ptid), GET_PID (ptid));
+ const char *obj_name = objfile_name (obj);
+
+ if (obj_name[0] != '/')
+ {
+ warning (_("Expected absolute pathname for libpthread in the"
+ " inferior, but got %ps."),
+ styled_string (file_name_style.style (), obj_name));
+ return false;
+ }
+
+ std::string path = obj_name;
+ size_t cp = path.rfind ('/');
+ /* This should at minimum hit the first character. */
+ gdb_assert (cp != std::string::npos);
+ path.resize (cp + 1);
+ if (subdir != NULL)
+ path = path + subdir + "/";
+ path += LIBTHREAD_DB_SO;
+
+ return try_thread_db_load (path.c_str (), true);
}
-\f
-void
-thread_db_init (struct target_ops *target)
+/* Handle $pdir in libthread-db-search-path.
+ Look for libthread_db in directory(libpthread)/SUBDIR.
+ SUBDIR may be NULL. It may also be something like "../lib64".
+ The result is true for success. */
+
+static bool
+try_thread_db_load_from_pdir (const char *subdir)
{
- target_beneath = target;
+ if (!auto_load_thread_db)
+ return false;
+
+ for (objfile *obj : current_program_space->objfiles ())
+ if (libpthread_name_p (objfile_name (obj)))
+ {
+ if (try_thread_db_load_from_pdir_1 (obj, subdir))
+ return true;
+
+ /* We may have found the separate-debug-info version of
+ libpthread, and it may live in a directory without a matching
+ libthread_db. */
+ if (obj->separate_debug_objfile_backlink != NULL)
+ return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink,
+ subdir);
+
+ return false;
+ }
+
+ return false;
}
-static void *
-verbose_dlsym (void *handle, const char *name)
+/* 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 bool
+try_thread_db_load_from_sdir (void)
{
- void *sym = dlsym (handle, name);
- if (sym == NULL)
- warning (_("Symbol \"%s\" not found in libthread_db: %s"), name, dlerror ());
- return sym;
+ return try_thread_db_load (LIBTHREAD_DB_SO, false);
}
-static int
-thread_db_load (void)
+/* Try to load libthread_db from directory DIR of length DIR_LEN.
+ The result is true for success. */
+
+static bool
+try_thread_db_load_from_dir (const char *dir, size_t dir_len)
{
- void *handle;
- td_err_e err;
+ if (!auto_load_thread_db)
+ return false;
- 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;
- }
+ std::string path = std::string (dir, dir_len) + "/" + LIBTHREAD_DB_SO;
- /* Initialize pointers to the dynamic library functions we will use.
- Essential functions first. */
+ return try_thread_db_load (path.c_str (), true);
+}
- td_init_p = verbose_dlsym (handle, "td_init");
- if (td_init_p == NULL)
- return 0;
+/* Search libthread_db_search_path for libthread_db which "agrees"
+ to work on current inferior.
+ The result is true for success. */
- td_ta_new_p = verbose_dlsym (handle, "td_ta_new");
- if (td_ta_new_p == NULL)
- return 0;
+static bool
+thread_db_load_search (void)
+{
+ bool rc = false;
- td_ta_map_id2thr_p = verbose_dlsym (handle, "td_ta_map_id2thr");
- if (td_ta_map_id2thr_p == NULL)
- return 0;
+ std::vector<gdb::unique_xmalloc_ptr<char>> dir_vec
+ = dirnames_to_char_ptr_vec (libthread_db_search_path);
- 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;
+ for (const gdb::unique_xmalloc_ptr<char> &this_dir_up : dir_vec)
+ {
+ const char *this_dir = this_dir_up.get ();
+ const int pdir_len = sizeof ("$pdir") - 1;
+ size_t this_dir_len;
- td_thr_validate_p = verbose_dlsym (handle, "td_thr_validate");
- if (td_thr_validate_p == NULL)
- return 0;
+ this_dir_len = strlen (this_dir);
- td_thr_get_info_p = verbose_dlsym (handle, "td_thr_get_info");
- if (td_thr_get_info_p == NULL)
- return 0;
+ if (strncmp (this_dir, "$pdir", pdir_len) == 0
+ && (this_dir[pdir_len] == '\0'
+ || this_dir[pdir_len] == '/'))
+ {
+ const char *subdir = NULL;
- /* Initialize the library. */
- err = td_init_p ();
- if (err != TD_OK)
- {
- warning (_("Cannot initialize libthread_db: %s"), thread_db_err_str (err));
- return 0;
+ std::string subdir_holder;
+ if (this_dir[pdir_len] == '/')
+ {
+ subdir_holder = std::string (this_dir + pdir_len + 1);
+ subdir = subdir_holder.c_str ();
+ }
+ rc = try_thread_db_load_from_pdir (subdir);
+ if (rc)
+ break;
+ }
+ else if (strcmp (this_dir, "$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;
+ }
+ }
}
- /* 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;
+ if (libthread_db_debug)
+ fprintf_unfiltered (gdb_stdlog,
+ _("thread_db_load_search returning %d\n"), rc);
+ return rc;
}
-static td_err_e
-enable_thread_event (td_thragent_t *thread_agent, int event, CORE_ADDR *bp)
+/* Return true if the inferior has a libpthread. */
+
+static bool
+has_libpthread (void)
{
- td_notify_t notify;
- td_err_e err;
+ for (objfile *obj : current_program_space->objfiles ())
+ if (libpthread_name_p (objfile_name (obj)))
+ return true;
- /* Get the breakpoint address for thread EVENT. */
- err = td_ta_event_addr_p (thread_agent, event, ¬ify);
- if (err != TD_OK)
- return err;
-
- /* Set up the breakpoint. */
- gdb_assert (exec_bfd);
- (*bp) = (gdbarch_convert_from_func_ptr_addr
- (current_gdbarch,
- /* Do proper sign extension for the target. */
- (bfd_get_sign_extend_vma (exec_bfd) > 0
- ? (CORE_ADDR) (intptr_t) notify.u.bptaddr
- : (CORE_ADDR) (uintptr_t) notify.u.bptaddr),
- ¤t_target));
- create_thread_event_breakpoint ((*bp));
-
- return TD_OK;
+ return false;
}
-static void
-enable_thread_event_reporting (void)
+/* Attempt to load and initialize libthread_db.
+ Return 1 on success. */
+
+static bool
+thread_db_load (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
+ struct thread_db_info *info;
- /* 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;
+ info = get_thread_db_info (current_inferior ()->process_target (),
+ inferior_ptid.pid ());
- /* 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 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);
+ if (info != NULL)
+ return true;
- 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;
- }
+ /* Don't attempt to use thread_db on executables not running
+ yet. */
+ if (!target_has_registers)
+ return false;
- /* Delete previous thread event breakpoints, if any. */
- remove_thread_event_breakpoints ();
- td_create_bp_addr = 0;
- td_death_bp_addr = 0;
+ /* Don't attempt to use thread_db for remote targets. */
+ if (!(target_can_run () || core_bfd))
+ return false;
- /* 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;
- }
+ if (thread_db_load_search ())
+ return true;
- /* Set up the thread death event. */
- err = enable_thread_event (thread_agent, TD_DEATH, &td_death_bp_addr);
- if (err != TD_OK)
+ /* We couldn't find a libthread_db.
+ If the inferior has a libpthread warn the user. */
+ if (has_libpthread ())
{
- warning (_("Unable to get location for thread death breakpoint: %s"),
- thread_db_err_str (err));
- return;
+ warning (_("Unable to find libthread_db matching inferior's thread"
+ " library, thread debugging will not be available."));
+ return false;
}
-}
-
-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;
+ /* Either this executable isn't using libpthread at all, or it is
+ statically linked. Since we can't easily distinguish these two cases,
+ no warning is issued. */
+ return false;
}
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);
{
if (sigismember (&mask, i))
{
- if (signal_stop_update (target_signal_from_host (i), 0))
+ if (signal_stop_update (gdb_signal_from_host (i), 0))
sigaddset (&thread_stop_set, i);
- if (signal_print_update (target_signal_from_host (i), 0))
+ if (signal_print_update (gdb_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
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;
-
- printf_unfiltered (_("Using host libthread_db library \"%s\".\n"),
- library);
- already_loaded = 1;
- }
-
- if (using_thread_db)
- /* Nothing to do. The thread library was already detected and the
- target vector was already activated. */
- return;
-
- /* Don't attempt to use thread_db on targets which can not run
- (executables not running yet, core files) for now. */
- if (!target_has_execution)
- return;
-
- /* Don't attempt to use thread_db for remote targets. */
- if (!target_can_run (¤t_target))
+ if (!thread_db_load ())
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;
- }
}
+/* This function is called via the new_objfile observer. */
+
static void
thread_db_new_objfile (struct objfile *objfile)
{
- if (objfile != NULL)
+ /* This observer must always be called with inferior_ptid set
+ correctly. */
+
+ if (objfile != NULL
+ /* libpthread with separate debug info has its debug info file already
+ loaded (and notified without successful thread_db initialization)
+ the time gdb::observers::new_objfile.notify is called for the library itself.
+ Static executables have their separate debug info loaded already
+ before the inferior has started. */
+ && objfile->separate_debug_objfile_backlink == NULL
+ /* Only check for thread_db if we loaded libpthread,
+ or if this is the main symbol file.
+ We need to check OBJF_MAINLINE to handle the case of debugging
+ a statically linked executable AND the symbol file is specified AFTER
+ the exec file is loaded (e.g., gdb -c core ; file foo).
+ For dynamically linked executables, libpthread can be near the end
+ of the list of shared libraries to load, and in an app of several
+ thousand shared libraries, this can otherwise be painful. */
+ && ((objfile->flags & OBJF_MAINLINE) != 0
+ || libpthread_name_p (objfile_name (objfile))))
check_for_thread_db ();
-
- 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)
+check_pid_namespace_match (void)
{
- 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))
+ /* Check is only relevant for local targets targets. */
+ if (target_can_run ())
{
- tp = find_thread_pid (ptid);
- gdb_assert (tp != NULL);
+ /* If the child is in a different PID namespace, its idea of its
+ PID will differ from our idea of its PID. When we scan the
+ child's thread list, we'll mistakenly think it has no threads
+ since the thread PID fields won't match the PID we give to
+ libthread_db. */
+ if (!linux_ns_same (inferior_ptid.pid (), LINUX_NS_PID))
+ {
+ warning (_ ("Target and debugger are in different PID "
+ "namespaces; thread lists and other data are "
+ "likely unreliable. "
+ "Connect to gdbserver inside the container."));
+ }
+ }
+}
- if (!tp->private->dying)
- return;
+/* This function is called via the inferior_created observer.
+ This handles the case of debugging statically linked executables. */
- delete_thread (ptid);
- }
+static void
+thread_db_inferior_created (struct target_ops *target, int from_tty)
+{
+ check_pid_namespace_match ();
+ check_for_thread_db ();
+}
- check_thread_signals ();
+/* Update the thread's state (what's displayed in "info threads"),
+ from libthread_db thread state information. */
- if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
- return; /* A zombie thread -- do not attach. */
+static void
+update_thread_state (thread_db_thread_info *priv,
+ const td_thrinfo_t *ti_p)
+{
+ priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN
+ || ti_p->ti_state == TD_THR_ZOMBIE);
+}
- /* Under GNU/Linux, we have to attach to each and every thread. */
- if (lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)), 0) < 0)
- return;
+/* Record a new thread in GDB's thread list. Creates the thread's
+ private info. If TP is NULL or TP is marked as having exited,
+ creates a new thread. Otherwise, uses TP. */
- /* 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));
+static struct thread_info *
+record_thread (struct thread_db_info *info,
+ struct thread_info *tp,
+ ptid_t ptid, const td_thrhandle_t *th_p,
+ const td_thrinfo_t *ti_p)
+{
+ /* A thread ID of zero may mean the thread library has not
+ initialized yet. Leave private == NULL until the thread library
+ has initialized. */
+ if (ti_p->ti_tid == 0)
+ return tp;
+
+ /* Construct the thread's private data. */
+ thread_db_thread_info *priv = new thread_db_thread_info;
+
+ priv->th = *th_p;
+ priv->tid = ti_p->ti_tid;
+ update_thread_state (priv, ti_p);
+
+ /* Add the thread to GDB's thread list. If we already know about a
+ thread with this PTID, but it's marked exited, then the kernel
+ reused the tid of an old thread. */
+ if (tp == NULL || tp->state == THREAD_EXITED)
+ tp = add_thread_with_info (info->process_target, ptid, priv);
+ else
+ tp->priv.reset (priv);
- if (verbose)
- printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid));
+ if (target_has_execution)
+ check_thread_signals ();
- /* 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));
+ return tp;
}
-static void
-thread_db_attach (char *args, int from_tty)
+void
+thread_db_target::detach (inferior *inf, int from_tty)
{
- target_beneath->to_attach (args, from_tty);
+ delete_thread_db_info (inf->process_target (), inf->pid);
- /* Destroy thread info; it's no longer valid. */
- init_thread_list ();
+ beneath ()->detach (inf, from_tty);
- /* The child process is now the actual multi-threaded
- program. Snatch its process ID... */
- proc_handle.pid = GET_PID (inferior_ptid);
+ /* NOTE: From this point on, inferior_ptid is null_ptid. */
- /* ...and perform the remaining initialization steps. */
- enable_thread_event_reporting ();
- thread_db_find_new_threads ();
+ /* Detach the thread_db target from this inferior. */
+ unpush_target (this);
}
-static void
-detach_thread (ptid_t ptid, int verbose)
+ptid_t
+thread_db_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
+ int options)
{
- struct thread_info *thread_info;
+ struct thread_db_info *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;
-}
+ process_stratum_target *beneath
+ = as_process_stratum_target (this->beneath ());
-static void
-thread_db_detach (char *args, int from_tty)
-{
- disable_thread_event_reporting ();
+ ptid = beneath->wait (ptid, ourstatus, options);
- /* 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);
+ switch (ourstatus->kind)
+ {
+ case TARGET_WAITKIND_IGNORE:
+ case TARGET_WAITKIND_EXITED:
+ case TARGET_WAITKIND_THREAD_EXITED:
+ case TARGET_WAITKIND_SIGNALLED:
+ return ptid;
+ }
- /* Forget about the child's process ID. We shouldn't need it
- anymore. */
- proc_handle.pid = 0;
+ info = get_thread_db_info (beneath, ptid.pid ());
- target_beneath->to_detach (args, from_tty);
-}
+ /* If this process isn't using thread_db, we're done. */
+ if (info == NULL)
+ return ptid;
-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. */
+ if (ourstatus->kind == TARGET_WAITKIND_EXECD)
+ {
+ /* New image, it may or may not end up using thread_db. Assume
+ not unless we find otherwise. */
+ delete_thread_db_info (beneath, ptid.pid ());
+ unpush_target (this);
- thread->private->th_valid = 0;
- thread->private->ti_valid = 0;
+ return ptid;
+ }
- return 0;
+ /* Fill in the thread's user-level thread id and status. */
+ thread_from_lwp (find_thread_ptid (beneath, ptid), ptid);
+
+ return ptid;
}
-static void
-thread_db_resume (ptid_t ptid, int step, enum target_signal signo)
+void
+thread_db_target::mourn_inferior ()
{
- struct cleanup *old_chain = save_inferior_ptid ();
+ process_stratum_target *target_beneath
+ = as_process_stratum_target (this->beneath ());
- if (GET_PID (ptid) == -1)
- inferior_ptid = lwp_from_thread (inferior_ptid);
- else if (is_thread (ptid))
- ptid = lwp_from_thread (ptid);
+ delete_thread_db_info (target_beneath, inferior_ptid.pid ());
- /* Clear cached data which may not be valid after the resume. */
- iterate_over_threads (clear_lwpid_callback, NULL);
+ target_beneath->mourn_inferior ();
- target_beneath->to_resume (ptid, step, signo);
-
- do_cleanups (old_chain);
+ /* Detach the thread_db target from this inferior. */
+ unpush_target (this);
}
-/* 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. */
+struct callback_data
+{
+ struct thread_db_info *info;
+ int new_threads;
+};
-static void
-check_event (ptid_t ptid)
+static int
+find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
{
- 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.
+ struct thread_info *tp;
+ struct callback_data *cb_data = (struct callback_data *) data;
+ struct thread_db_info *info = cb_data->info;
- 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. */
+ err = info->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));
- loop = 1;
+ if (ti.ti_lid == -1)
+ {
+ /* 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 (libthread_db_debug)
+ fprintf_unfiltered (gdb_stdlog,
+ "thread_db: skipping exited and "
+ "joined thread (0x%lx)\n",
+ (unsigned long) ti.ti_tid);
+ return 0;
+ }
- do
+ if (ti.ti_tid == 0)
{
- err = td_ta_event_getmsg_p (thread_agent, &msg);
- if (err != TD_OK)
- {
- if (err == TD_NOMSG)
- return;
+ /* 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. */
- error (_("Cannot get thread event message: %s"),
- thread_db_err_str (err));
- }
+ /* In that case, we're not stopped in a fork syscall and don't
+ need this glibc bug workaround. */
+ info->need_stale_parent_threads_check = 0;
- 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));
+ return 0;
+ }
- ptid = ptid_build (GET_PID (ptid), ti.ti_lid, ti.ti_tid);
+ /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
+ bit expensive, as it needs to open /proc/pid/status, so try to
+ avoid doing the work if we know we don't have to. */
+ if (info->need_stale_parent_threads_check)
+ {
+ int tgid = linux_proc_get_tgid (ti.ti_lid);
- 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);
+ if (tgid != -1 && tgid != info->pid)
+ return 0;
+ }
+
+ ptid_t ptid (info->pid, ti.ti_lid);
+ tp = find_thread_ptid (info->process_target, ptid);
+ if (tp == NULL || tp->priv == NULL)
+ record_thread (info, tp, ptid, th_p, &ti);
- break;
+ return 0;
+}
- case TD_DEATH:
+/* Helper for thread_db_find_new_threads_2.
+ Returns number of new threads found. */
- if (!in_thread_list (ptid))
- error (_("Spurious thread death event."));
+static int
+find_new_threads_once (struct thread_db_info *info, int iteration,
+ td_err_e *errp)
+{
+ struct callback_data data;
+ td_err_e err = TD_ERR;
- detach_thread (ptid, 1);
+ data.info = info;
+ data.new_threads = 0;
- break;
+ /* See comment in thread_db_update_thread_list. */
+ gdb_assert (info->td_ta_thr_iter_p != NULL);
- default:
- error (_("Spurious thread event."));
+ try
+ {
+ /* 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);
+ }
+ catch (const gdb_exception_error &except)
+ {
+ if (libthread_db_debug)
+ {
+ exception_fprintf (gdb_stdlog, except,
+ "Warning: find_new_threads_once: ");
}
}
- while (loop);
-}
-static ptid_t
-thread_db_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
-{
- extern ptid_t trap_ptid;
+ if (libthread_db_debug)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ _("Found %d new threads in iteration %d.\n"),
+ data.new_threads, iteration);
+ }
- if (GET_PID (ptid) != -1 && is_thread (ptid))
- ptid = lwp_from_thread (ptid);
+ if (errp != NULL)
+ *errp = err;
- ptid = target_beneath->to_wait (ptid, ourstatus);
+ return data.new_threads;
+}
- 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;
+/* Search for new threads, accessing memory through stopped thread
+ 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_2 (thread_info *stopped, bool until_no_new)
+{
+ td_err_e err = TD_OK;
+ struct thread_db_info *info;
+ int i, loop;
- if (ourstatus->kind == TARGET_WAITKIND_EXITED
- || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
- return pid_to_ptid (-1);
+ info = get_thread_db_info (stopped->inf->process_target (),
+ stopped->ptid.pid ());
- if (ourstatus->kind == TARGET_WAITKIND_EXECD)
- {
- remove_thread_event_breakpoints ();
- unpush_target (&thread_db_ops);
- using_thread_db = 0;
+ /* Access an lwp we know is stopped. */
+ info->proc_handle.thread = stopped;
- return pid_to_ptid (GET_PID (ptid));
+ 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 && err == TD_OK; ++i, ++loop)
+ if (find_new_threads_once (info, i, &err) != 0)
+ {
+ /* Found some new threads. Restart the loop from beginning. */
+ loop = -1;
+ }
}
+ else
+ find_new_threads_once (info, 0, &err);
- 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;
+ if (err != TD_OK)
+ error (_("Cannot find new threads: %s"), thread_db_err_str (err));
}
static void
-thread_db_kill (void)
+thread_db_find_new_threads_1 (thread_info *stopped)
{
- /* 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 ();
+ thread_db_find_new_threads_2 (stopped, 0);
}
-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);
-}
+/* Implement the to_update_thread_list target method for this
+ target. */
-static void
-thread_db_post_startup_inferior (ptid_t ptid)
+void
+thread_db_target::update_thread_list ()
{
- 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);
+ struct thread_db_info *info;
- /* ...and perform the remaining initialization steps. */
- enable_thread_event_reporting ();
- thread_db_find_new_threads ();
+ prune_threads ();
+
+ for (inferior *inf : all_inferiors ())
+ {
+ if (inf->pid == 0)
+ continue;
+
+ info = get_thread_db_info (inf->process_target (), inf->pid);
+ if (info == NULL)
+ continue;
+
+ thread_info *thread = any_live_thread_of_inferior (inf);
+ if (thread == NULL || thread->executing)
+ continue;
+
+ /* 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 GDB to get
+ stuck in an infinite loop. To avoid pausing all threads
+ whenever the core wants to refresh the thread list, we
+ instead use thread_from_lwp immediately when we see an LWP
+ stop. That uses thread_db entry points that do not walk
+ libpthread's thread list, so should be safe, as well as more
+ efficient. */
+ if (thread->inf->has_execution ())
+ continue;
+
+ thread_db_find_new_threads_1 (thread);
}
+
+ /* Give the beneath target a chance to do extra processing. */
+ this->beneath ()->update_thread_list ();
}
-static void
-thread_db_mourn_inferior (void)
+std::string
+thread_db_target::pid_to_str (ptid_t ptid)
{
- /* Forget about the child's process ID. We shouldn't need it
- anymore. */
- proc_handle.pid = 0;
+ thread_info *thread_info = find_thread_ptid (current_inferior (), ptid);
- target_beneath->to_mourn_inferior ();
+ if (thread_info != NULL && thread_info->priv != NULL)
+ {
+ thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
- /* 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 ();
+ return string_printf ("Thread 0x%lx (LWP %ld)",
+ (unsigned long) priv->tid, ptid.lwp ());
+ }
- /* Detach thread_db target ops. */
- unpush_target (&thread_db_ops);
- using_thread_db = 0;
+ return beneath ()->pid_to_str (ptid);
}
-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));
+/* Return a string describing the state of the thread specified by
+ INFO. */
- if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
- return 0; /* A zombie -- ignore. */
+const char *
+thread_db_target::extra_thread_info (thread_info *info)
+{
+ if (info->priv == NULL)
+ return NULL;
- ptid = ptid_build (GET_PID (inferior_ptid), ti.ti_lid, ti.ti_tid);
+ thread_db_thread_info *priv = get_thread_db_thread_info (info);
- if (!in_thread_list (ptid))
- attach_thread (ptid, th_p, &ti, 1);
+ if (priv->dying)
+ return "Exiting";
- return 0;
+ return NULL;
}
-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));
-}
+/* Return pointer to the thread_info struct which corresponds to
+ THREAD_HANDLE (having length HANDLE_LEN). */
-static char *
-thread_db_pid_to_str (ptid_t ptid)
+thread_info *
+thread_db_target::thread_handle_to_thread_info (const gdb_byte *thread_handle,
+ int handle_len,
+ inferior *inf)
{
- if (is_thread (ptid))
- {
- static char buf[64];
- struct thread_info *thread_info;
+ thread_t handle_tid;
+
+ /* When debugging a 32-bit target from a 64-bit host, handle_len
+ will be 4 and sizeof (handle_tid) will be 8. This requires
+ a different cast than the more straightforward case where
+ the sizes are the same.
+
+ Use "--target_board unix/-m32" from a native x86_64 linux build
+ to test the 32/64-bit case. */
+ if (handle_len == 4 && sizeof (handle_tid) == 8)
+ handle_tid = (thread_t) * (const uint32_t *) thread_handle;
+ else if (handle_len == sizeof (handle_tid))
+ handle_tid = * (const thread_t *) thread_handle;
+ else
+ error (_("Thread handle size mismatch: %d vs %zu (from libthread_db)"),
+ handle_len, sizeof (handle_tid));
- thread_info = find_thread_pid (ptid);
- if (thread_info == NULL)
- snprintf (buf, sizeof (buf), "Thread %ld (LWP %ld) (Missing)",
- GET_THREAD (ptid), GET_LWP (ptid));
- else
- snprintf (buf, sizeof (buf), "Thread %ld (LWP %ld)",
- GET_THREAD (ptid), GET_LWP (ptid));
+ for (thread_info *tp : inf->non_exited_threads ())
+ {
+ thread_db_thread_info *priv = get_thread_db_thread_info (tp);
- return buf;
+ if (priv != NULL && handle_tid == priv->tid)
+ return tp;
}
- if (target_beneath->to_pid_to_str (ptid))
- return target_beneath->to_pid_to_str (ptid);
-
- return normal_pid_to_str (ptid);
+ return NULL;
}
-/* Return a string describing the state of the thread specified by
- INFO. */
+/* Return the thread handle associated the thread_info pointer TP. */
-static char *
-thread_db_extra_thread_info (struct thread_info *info)
+gdb::byte_vector
+thread_db_target::thread_info_to_thread_handle (struct thread_info *tp)
{
- if (info->private->dying)
- return "Exiting";
+ thread_db_thread_info *priv = get_thread_db_thread_info (tp);
- return NULL;
+ if (priv == NULL)
+ return gdb::byte_vector ();
+
+ int handle_size = sizeof (priv->tid);
+ gdb::byte_vector rv (handle_size);
+
+ memcpy (rv.data (), &priv->tid, handle_size);
+
+ return rv;
}
/* 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)
+CORE_ADDR
+thread_db_target::get_thread_local_address (ptid_t ptid,
+ CORE_ADDR lm,
+ CORE_ADDR offset)
{
- if (is_thread (ptid))
- {
- td_err_e err;
- void *address;
- struct thread_info *thread_info;
-
- /* glibc doesn't provide the needed interface. */
- if (!td_thr_tls_get_addr_p)
- throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
- _("No TLS library support"));
+ struct thread_info *thread_info;
+ process_stratum_target *beneath
+ = as_process_stratum_target (this->beneath ());
+ /* Find the matching thread. */
+ thread_info = find_thread_ptid (beneath, ptid);
- /* Caller should have verified that lm != 0. */
- gdb_assert (lm != 0);
+ /* We may not have discovered the thread yet. */
+ if (thread_info != NULL && thread_info->priv == NULL)
+ thread_info = thread_from_lwp (thread_info, ptid);
- /* Get info about the thread. */
- thread_info = find_thread_pid (ptid);
- thread_db_map_id2thr (thread_info, 1);
+ if (thread_info != NULL && thread_info->priv != NULL)
+ {
+ td_err_e err;
+ psaddr_t address;
+ thread_db_info *info = get_thread_db_info (beneath, ptid.pid ());
+ thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
/* Finally, get the address of the variable. */
- err = td_thr_tls_get_addr_p (&thread_info->private->th,
- (void *)(size_t) lm,
- offset, &address);
+ if (lm != 0)
+ {
+ /* glibc doesn't provide the needed interface. */
+ if (!info->td_thr_tls_get_addr_p)
+ throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
+ _("No TLS library support"));
+
+ /* 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 (&priv->th,
+ (psaddr_t)(uintptr_t) lm,
+ offset, &address);
+ }
+ else
+ {
+ /* If glibc doesn't provide the needed interface throw an error
+ that LM is zero - normally cases it should not be. */
+ if (!info->td_thr_tlsbase_p)
+ throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR,
+ _("TLS load module not found"));
+
+ /* 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 = info->td_thr_tlsbase_p (&priv->th, 1, &address);
+ address = (char *) address + offset;
+ }
#ifdef THREAD_DB_HAS_TD_NOTALLOC
/* The memory hasn't been allocated, yet. */
: (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"));
+ return beneath->get_thread_local_address (ptid, lm, offset);
}
-static void
-init_thread_db_ops (void)
+/* Implement the to_get_ada_task_ptid target method for this target. */
+
+ptid_t
+thread_db_target::get_ada_task_ptid (long lwp, long thread)
{
- 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_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_find_new_threads = thread_db_find_new_threads;
- thread_db_ops.to_pid_to_str = thread_db_pid_to_str;
- thread_db_ops.to_stratum = thread_stratum;
- thread_db_ops.to_has_thread_control = tc_schedlock;
- thread_db_ops.to_get_thread_local_address
- = thread_db_get_thread_local_address;
- thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info;
- thread_db_ops.to_magic = OPS_MAGIC;
+ /* NPTL uses a 1:1 model, so the LWP id suffices. */
+ return ptid_t (inferior_ptid.pid (), lwp, 0);
}
void
-_initialize_thread_db (void)
+thread_db_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
+{
+ process_stratum_target *beneath
+ = as_process_stratum_target (this->beneath ());
+
+ thread_db_info *info
+ = get_thread_db_info (beneath, (ptid == minus_one_ptid
+ ? inferior_ptid.pid ()
+ : ptid.pid ()));
+
+ /* This workaround is only needed for child fork lwps stopped in a
+ PTRACE_O_TRACEFORK event. When the inferior is resumed, the
+ workaround can be disabled. */
+ if (info)
+ info->need_stale_parent_threads_check = 0;
+
+ beneath->resume (ptid, step, signo);
+}
+
+/* std::sort helper function for info_auto_load_libthread_db, sort the
+ thread_db_info pointers primarily by their FILENAME and secondarily by their
+ PID, both in ascending order. */
+
+static bool
+info_auto_load_libthread_db_compare (const struct thread_db_info *a,
+ const struct thread_db_info *b)
+{
+ int retval;
+
+ retval = strcmp (a->filename, b->filename);
+ if (retval)
+ return retval < 0;
+
+ return a->pid < b->pid;
+}
+
+/* Implement 'info auto-load libthread-db'. */
+
+static void
+info_auto_load_libthread_db (const char *args, int from_tty)
{
- /* Only initialize the module if we can load libthread_db. */
- if (thread_db_load ())
+ struct ui_out *uiout = current_uiout;
+ const char *cs = args ? args : "";
+ struct thread_db_info *info;
+ unsigned unique_filenames;
+ size_t max_filename_len, pids_len;
+ int i;
+
+ cs = skip_spaces (cs);
+ if (*cs)
+ error (_("'info auto-load libthread-db' does not accept any parameters"));
+
+ std::vector<struct thread_db_info *> array;
+ for (info = thread_db_list; info; info = info->next)
+ if (info->filename != NULL)
+ array.push_back (info);
+
+ /* Sort ARRAY by filenames and PIDs. */
+ std::sort (array.begin (), array.end (),
+ info_auto_load_libthread_db_compare);
+
+ /* Calculate the number of unique filenames (rows) and the maximum string
+ length of PIDs list for the unique filenames (columns). */
+
+ unique_filenames = 0;
+ max_filename_len = 0;
+ pids_len = 0;
+ for (i = 0; i < array.size (); i++)
{
- init_thread_db_ops ();
- add_target (&thread_db_ops);
+ int pid = array[i]->pid;
+ size_t this_pid_len;
- /* Add ourselves to objfile event chain. */
- target_new_objfile_chain = deprecated_target_new_objfile_hook;
- deprecated_target_new_objfile_hook = thread_db_new_objfile;
+ for (this_pid_len = 0; pid != 0; pid /= 10)
+ this_pid_len++;
+
+ if (i == 0 || strcmp (array[i - 1]->filename, array[i]->filename) != 0)
+ {
+ unique_filenames++;
+ max_filename_len = std::max (max_filename_len,
+ strlen (array[i]->filename));
+
+ if (i > 0)
+ pids_len -= strlen (", ");
+ pids_len = 0;
+ }
+ pids_len += this_pid_len + strlen (", ");
}
+ if (i)
+ pids_len -= strlen (", ");
+
+ /* Table header shifted right by preceding "libthread-db: " would not match
+ its columns. */
+ if (array.size () > 0 && args == auto_load_info_scripts_pattern_nl)
+ uiout->text ("\n");
+
+ {
+ ui_out_emit_table table_emitter (uiout, 2, unique_filenames,
+ "LinuxThreadDbTable");
+
+ uiout->table_header (max_filename_len, ui_left, "filename", "Filename");
+ uiout->table_header (pids_len, ui_left, "PIDs", "Pids");
+ uiout->table_body ();
+
+ /* Note I is incremented inside the cycle, not at its end. */
+ for (i = 0; i < array.size ();)
+ {
+ ui_out_emit_tuple tuple_emitter (uiout, NULL);
+
+ info = array[i];
+ uiout->field_string ("filename", info->filename);
+
+ std::string pids;
+ while (i < array.size () && strcmp (info->filename,
+ array[i]->filename) == 0)
+ {
+ if (!pids.empty ())
+ pids += ", ";
+ string_appendf (pids, "%u", array[i]->pid);
+ i++;
+ }
+
+ uiout->field_string ("pids", pids.c_str ());
+
+ uiout->text ("\n");
+ }
+ }
+
+ if (array.empty ())
+ uiout->message (_("No auto-loaded libthread-db.\n"));
+}
+
+/* Implement 'maintenance check libthread-db'. */
+
+static void
+maintenance_check_libthread_db (const char *args, int from_tty)
+{
+ int inferior_pid = inferior_ptid.pid ();
+ struct thread_db_info *info;
+
+ if (inferior_pid == 0)
+ error (_("No inferior running"));
+
+ info = get_thread_db_info (current_inferior ()->process_target (),
+ inferior_pid);
+ if (info == NULL)
+ error (_("No libthread_db loaded"));
+
+ check_thread_db (info, true);
+}
+
+void _initialize_thread_db ();
+void
+_initialize_thread_db ()
+{
+ /* Defer loading of libthread_db.so until inferior is running.
+ This allows gdb to load correct libthread_db for a given
+ executable -- there could be multiple versions of glibc,
+ and until there is a running inferior, we can't tell which
+ libthread_db is the correct one to load. */
+
+ libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
+
+ add_setshow_optional_filename_cmd ("libthread-db-search-path",
+ class_support,
+ &libthread_db_search_path, _("\
+Set search path for libthread_db."), _("\
+Show the current search path or libthread_db."), _("\
+This path is used to search for libthread_db to be loaded into \
+gdb itself.\n\
+Its value is a colon (':') separate list of directories to search.\n\
+Setting the search path to an empty list resets it to its default value."),
+ set_libthread_db_search_path,
+ NULL,
+ &setlist, &showlist);
+
+ add_setshow_zuinteger_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_setshow_boolean_cmd ("libthread-db", class_support,
+ &auto_load_thread_db, _("\
+Enable or disable auto-loading of inferior specific libthread_db."), _("\
+Show whether auto-loading inferior specific libthread_db is enabled."), _("\
+If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
+locations to load libthread_db compatible with the inferior.\n\
+Standard system libthread_db still gets loaded even with this option off.\n\
+This option has security implications for untrusted inferiors."),
+ NULL, show_auto_load_thread_db,
+ auto_load_set_cmdlist_get (),
+ auto_load_show_cmdlist_get ());
+
+ add_cmd ("libthread-db", class_info, info_auto_load_libthread_db,
+ _("Print the list of loaded inferior specific libthread_db.\n\
+Usage: info auto-load libthread-db"),
+ auto_load_info_cmdlist_get ());
+
+ add_cmd ("libthread-db", class_maintenance,
+ maintenance_check_libthread_db, _("\
+Run integrity checks on the current inferior's libthread_db."),
+ &maintenancechecklist);
+
+ add_setshow_boolean_cmd ("check-libthread-db",
+ class_maintenance,
+ &check_thread_db_on_load, _("\
+Set whether to check libthread_db at load time."), _("\
+Show whether to check libthread_db at load time."), _("\
+If enabled GDB will run integrity checks on inferior specific libthread_db\n\
+as they are loaded."),
+ NULL,
+ NULL,
+ &maintenance_set_cmdlist,
+ &maintenance_show_cmdlist);
+
+ /* Add ourselves to objfile event chain. */
+ gdb::observers::new_objfile.attach (thread_db_new_objfile);
+
+ /* Add ourselves to inferior_created event chain.
+ This is needed to handle debugging statically linked programs where
+ the new_objfile observer won't get called for libpthread. */
+ gdb::observers::inferior_created.attach (thread_db_inferior_created);
}
projects / deliverable / binutils-gdb.git / blobdiff