/* 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.
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 "observer.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;
+
+/* 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;
+
+/* 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. */
+
+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);
+}
/* If we're running on GNU/Linux, we must explicitly attach to any new
threads. */
/* This module's target vector. */
-static struct target_ops thread_db_ops;
-
-/* The target vector that we call for things this module can't handle. */
-static struct target_ops *target_beneath;
-
-/* Non-zero if we're using this module's target vector. */
-static int using_thread_db;
+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;
}
}
+
+/* Fetch the user-level thread id of PTID. STOPPED is a stopped
+ thread that we can use to access memory. */
+
+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_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);
+
+ 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. */
+ tp = find_thread_ptid (stopped->inf->process_target (), ptid);
+ return record_thread (info, tp, ptid, &th, &ti);
+}
\f
-/* Return 1 if any threads have been registered. There may be none if
- the threading library is not fully initialized yet. */
-static int
-have_threads_callback (struct thread_info *thread, void *dummy)
+/* 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 ());
+
+ 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
-have_threads (void)
+inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min)
{
- return iterate_over_threads (have_threads_callback, NULL) != NULL;
+ 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;
}
-/* A callback function for td_ta_thr_iter, which we use to map all
- threads to LWPs.
+/* 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 (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))
+ {
+ exception_fprintf (gdb_stderr, except,
+ _("Warning: couldn't activate thread debugging "
+ "using libthread_db: "));
+ return 1;
+ }
+ }
- 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.
+ return 0;
+}
- If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise,
- zero is returned to indicate success. */
+/* 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
-thread_get_info_callback (const td_thrhandle_t *thp, void *infop)
+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;
- td_err_e err;
- struct thread_info *thread_info;
- ptid_t thread_ptid;
+ CALL (td_thr_get_info, th, &ti);
- err = td_thr_get_info_p (thp, &ti);
- if (err != TD_OK)
- error (_("thread_get_info_callback: cannot get thread info: %s"),
- thread_db_err_str (err));
+ LOG (" => %d", ti.ti_lid);
- /* Fill the cache. */
- thread_ptid = ptid_build (GET_PID (inferior_ptid), ti.ti_lid, ti.ti_tid);
- thread_info = find_thread_pid (thread_ptid);
+ 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);
+ }
- /* 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)
+ /* 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)
{
- if (infop != NULL)
- *(struct thread_info **) infop = thread_info;
- if (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)
{
- 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;
+ struct value_print_options opts;
+
+ get_user_print_options (&opts);
+ LOG (" = ");
+ value_print (val, gdb_stdlog, &opts);
}
- return TD_THR_ZOMBIE;
}
- if (thread_info == NULL)
+ LOG (" ... OK\n");
+
+#undef LOG
+#undef CHECK_1
+#undef CHECK
+#undef CALL_UNCHECKED
+#undef CHECK_CALL
+#undef CALL
+
+ return 0;
+}
+
+/* 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 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)
{
- /* 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);
+ if (warning_pre_print)
+ fputs_unfiltered (warning_pre_print, gdb_stderr);
+
+ exception_fprintf (gdb_stderr, except,
+ _("libthread_db integrity checks failed: "));
+
+ test_passed = false;
}
- memcpy (&thread_info->private->th, thp, sizeof (*thp));
- thread_info->private->th_valid = 1;
- memcpy (&thread_info->private->ti, &ti, sizeof (ti));
- thread_info->private->ti_valid = 1;
+ if (test_passed && log_progress)
+ debug_printf (_("libthread_db integrity checks passed.\n"));
- if (infop != NULL)
- *(struct thread_info **) infop = thread_info;
+ tdb_testinfo = NULL;
- return 0;
+ linux_unstop_all_lwps ();
+
+ return test_passed;
}
-/* Accessor functions for the thread_db information, with caching. */
+/* 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 void
-thread_db_map_id2thr (struct thread_info *thread_info, int fatal)
+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)
- err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (thread_info->ptid),
- &thread_info->private->th);
+#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)
+
+ 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 if we have glibc but a lower
- version. */
- libc_version = gnu_get_libc_version ();
- if (sscanf (libc_version, "%d.%d", &libc_major, &libc_minor) == 2
- && (libc_major > 2 || (libc_major == 2 && libc_minor > 1)))
-#endif
- td_event_addset (&events, TD_DEATH);
+ 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;
-
- if (info_verbose)
- printf_unfiltered (_("Using host libthread_db library \"%s\".\n"),
- library);
- already_loaded = 1;
- }
-
- if (using_thread_db)
- /* Nothing to do. The thread library was already detected and the
- target vector was already activated. */
- return;
-
- /* Don't attempt to use thread_db on targets which can not run
- (executables not running yet, core files) for now. */
- if (!target_has_execution)
+ if (!thread_db_load ())
return;
-
- /* Don't attempt to use thread_db for remote targets. */
- if (!target_can_run (¤t_target))
- return;
-
- /* Initialize the structure that identifies the child process. */
- proc_handle.pid = GET_PID (inferior_ptid);
-
- /* Now attempt to open a connection to the thread library. */
- err = td_ta_new_p (&proc_handle, &thread_agent);
- switch (err)
- {
- case TD_NOLIBTHREAD:
- /* No thread library was detected. */
- break;
-
- case TD_OK:
- printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
-
- /* The thread library was detected. Activate the thread_db target. */
- push_target (&thread_db_ops);
- using_thread_db = 1;
-
- enable_thread_event_reporting ();
- thread_db_find_new_threads ();
- break;
-
- default:
- warning (_("Cannot initialize thread debugging library: %s"),
- thread_db_err_str (err));
- break;
- }
}
+/* 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 ();
}
-/* 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 (!tp->private->dying)
- return;
-
- delete_thread (ptid);
+ /* 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."));
+ }
}
-
- check_thread_signals ();
-
- if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
- return; /* A zombie thread -- do not attach. */
-
- /* Under GNU/Linux, we have to attach to each and every thread. */
- if (lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)), 0) < 0)
- return;
-
- /* Add the thread to GDB's thread list. */
- tp = add_thread (ptid);
- tp->private = xmalloc (sizeof (struct private_thread_info));
- memset (tp->private, 0, sizeof (struct private_thread_info));
-
- if (verbose)
- printf_unfiltered (_("[New %s]\n"), target_pid_to_str (ptid));
-
- /* 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));
}
+/* This function is called via the inferior_created observer.
+ This handles the case of debugging statically linked executables. */
+
static void
-detach_thread (ptid_t ptid, int verbose)
+thread_db_inferior_created (struct target_ops *target, int from_tty)
{
- struct thread_info *thread_info;
-
- if (verbose)
- printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (ptid));
-
- /* Don't delete the thread now, because it still reports as active
- until it has executed a few instructions after the event
- breakpoint - if we deleted it now, "info threads" would cause us
- to re-attach to it. Just mark it as having had a TD_DEATH
- event. This means that we won't delete it from our thread list
- until we notice that it's dead (via prune_threads), or until
- something re-uses its thread ID. */
- thread_info = find_thread_pid (ptid);
- gdb_assert (thread_info != NULL);
- thread_info->private->dying = 1;
+ check_pid_namespace_match ();
+ check_for_thread_db ();
}
+/* Update the thread's state (what's displayed in "info threads"),
+ from libthread_db thread state information. */
+
static void
-thread_db_detach (char *args, int from_tty)
+update_thread_state (thread_db_thread_info *priv,
+ const td_thrinfo_t *ti_p)
{
- disable_thread_event_reporting ();
-
- /* There's no need to save & restore inferior_ptid here, since the
- inferior is not supposed to survive this function call. */
- inferior_ptid = lwp_from_thread (inferior_ptid);
-
- target_beneath->to_detach (args, from_tty);
-
- /* Should this be done by detach_command? */
- target_mourn_inferior ();
+ priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN
+ || ti_p->ti_state == TD_THR_ZOMBIE);
}
-static int
-clear_lwpid_callback (struct thread_info *thread, void *dummy)
+/* 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. */
+
+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)
{
- /* 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. */
+ /* 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);
- thread->private->th_valid = 0;
- thread->private->ti_valid = 0;
+ if (target_has_execution)
+ check_thread_signals ();
- return 0;
+ return tp;
}
-static void
-thread_db_resume (ptid_t ptid, int step, enum target_signal signo)
+void
+thread_db_target::detach (inferior *inf, int from_tty)
{
- struct cleanup *old_chain = save_inferior_ptid ();
-
- if (GET_PID (ptid) == -1)
- inferior_ptid = lwp_from_thread (inferior_ptid);
- else if (is_thread (ptid))
- ptid = lwp_from_thread (ptid);
+ delete_thread_db_info (inf->process_target (), inf->pid);
- /* Clear cached data which may not be valid after the resume. */
- iterate_over_threads (clear_lwpid_callback, NULL);
+ beneath ()->detach (inf, from_tty);
- target_beneath->to_resume (ptid, step, signo);
+ /* NOTE: From this point on, inferior_ptid is null_ptid. */
- 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. */
-
-static void
-check_event (ptid_t ptid)
+ptid_t
+thread_db_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
+ int options)
{
- td_event_msg_t msg;
- td_thrinfo_t ti;
- td_err_e err;
- CORE_ADDR stop_pc;
- int loop = 0;
+ struct thread_db_info *info;
- /* Bail out early if we're not at a thread event breakpoint. */
- stop_pc = read_pc_pid (ptid) - gdbarch_decr_pc_after_break (current_gdbarch);
- 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.
+ process_stratum_target *beneath
+ = as_process_stratum_target (this->beneath ());
- 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. */
+ ptid = beneath->wait (ptid, ourstatus, options);
- loop = 1;
-
- do
+ switch (ourstatus->kind)
{
- err = td_ta_event_getmsg_p (thread_agent, &msg);
- if (err != TD_OK)
- {
- if (err == TD_NOMSG)
- return;
-
- error (_("Cannot get thread event message: %s"),
- thread_db_err_str (err));
- }
-
- err = td_thr_get_info_p (msg.th_p, &ti);
- if (err != TD_OK)
- error (_("Cannot get thread info: %s"), thread_db_err_str (err));
-
- ptid = ptid_build (GET_PID (ptid), ti.ti_lid, ti.ti_tid);
-
- switch (msg.event)
- {
- case TD_CREATE:
- /* Call attach_thread whether or not we already know about a
- thread with this thread ID. */
- attach_thread (ptid, msg.th_p, &ti, 1);
-
- break;
-
- case TD_DEATH:
-
- if (!in_thread_list (ptid))
- error (_("Spurious thread death event."));
-
- detach_thread (ptid, 1);
-
- break;
-
- default:
- error (_("Spurious thread event."));
- }
+ case TARGET_WAITKIND_IGNORE:
+ case TARGET_WAITKIND_EXITED:
+ case TARGET_WAITKIND_THREAD_EXITED:
+ case TARGET_WAITKIND_SIGNALLED:
+ return ptid;
}
- while (loop);
-}
-static ptid_t
-thread_db_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
-{
- extern ptid_t trap_ptid;
-
- if (GET_PID (ptid) != -1 && is_thread (ptid))
- ptid = lwp_from_thread (ptid);
+ info = get_thread_db_info (beneath, ptid.pid ());
- ptid = target_beneath->to_wait (ptid, ourstatus);
-
- if (ourstatus->kind == TARGET_WAITKIND_EXITED
- || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
- return pid_to_ptid (-1);
+ /* If this process isn't using thread_db, we're done. */
+ if (info == NULL)
+ return ptid;
if (ourstatus->kind == TARGET_WAITKIND_EXECD)
{
- remove_thread_event_breakpoints ();
- unpush_target (&thread_db_ops);
- using_thread_db = 0;
+ /* 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);
- return pid_to_ptid (GET_PID (ptid));
+ return ptid;
}
- /* If we do not know about the main thread yet, this would be a good time to
- find it. */
- if (ourstatus->kind == TARGET_WAITKIND_STOPPED && !have_threads ())
- thread_db_find_new_threads ();
-
- if (ourstatus->kind == TARGET_WAITKIND_STOPPED
- && ourstatus->value.sig == TARGET_SIGNAL_TRAP)
- /* Check for a thread event. */
- check_event (ptid);
-
- if (have_threads ())
- {
- /* Change ptids back into the higher level PID + TID format. If
- the thread is dead and no longer on the thread list, we will
- get back a dead ptid. This can occur if the thread death
- event gets postponed by other simultaneous events. In such a
- case, we want to just ignore the event and continue on. */
-
- if (!ptid_equal (trap_ptid, null_ptid))
- trap_ptid = thread_from_lwp (trap_ptid);
-
- ptid = thread_from_lwp (ptid);
- if (GET_PID (ptid) == -1)
- ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
- }
+ /* 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_kill (void)
-{
- /* There's no need to save & restore inferior_ptid here, since the
- inferior isn't supposed to survive this function call. */
- inferior_ptid = lwp_from_thread (inferior_ptid);
- target_beneath->to_kill ();
-}
-
-static void
-thread_db_mourn_inferior (void)
+void
+thread_db_target::mourn_inferior ()
{
- /* Forget about the child's process ID. We shouldn't need it
- anymore. */
- proc_handle.pid = 0;
+ process_stratum_target *target_beneath
+ = as_process_stratum_target (this->beneath ());
- target_beneath->to_mourn_inferior ();
+ delete_thread_db_info (target_beneath, inferior_ptid.pid ());
- /* 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 ();
+ target_beneath->mourn_inferior ();
- /* Detach thread_db target ops. */
- unpush_target (&thread_db_ops);
- using_thread_db = 0;
+ /* Detach the thread_db target from this inferior. */
+ unpush_target (this);
}
+struct callback_data
+{
+ struct thread_db_info *info;
+ int new_threads;
+};
+
static int
find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
{
td_thrinfo_t ti;
td_err_e err;
- ptid_t ptid;
+ struct thread_info *tp;
+ struct callback_data *cb_data = (struct callback_data *) data;
+ struct thread_db_info *info = cb_data->info;
- err = td_thr_get_info_p (th_p, &ti);
+ 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));
- if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
- return 0; /* A zombie -- ignore. */
-
- ptid = ptid_build (GET_PID (inferior_ptid), ti.ti_lid, ti.ti_tid);
+ 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;
+ }
if (ti.ti_tid == 0)
{
/* A thread ID of zero means that this is the main thread, but
glibc has not yet initialized thread-local storage and the
pthread library. We do not know what the thread's TID will
- be yet. Just enable event reporting and otherwise ignore
- it. */
+ be yet. */
- 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));
+ /* 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;
return 0;
}
- if (!in_thread_list (ptid))
- attach_thread (ptid, th_p, &ti, 1);
+ /* 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);
+
+ 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);
return 0;
}
+/* Helper for thread_db_find_new_threads_2.
+ Returns number of new threads found. */
+
+static int
+find_new_threads_once (struct thread_db_info *info, int iteration,
+ td_err_e *errp)
+{
+ struct callback_data data;
+ td_err_e err = TD_ERR;
+
+ data.info = info;
+ data.new_threads = 0;
+
+ /* See comment in thread_db_update_thread_list. */
+ gdb_assert (info->td_ta_thr_iter_p != NULL);
+
+ 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: ");
+ }
+ }
+
+ if (libthread_db_debug)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ _("Found %d new threads in iteration %d.\n"),
+ data.new_threads, iteration);
+ }
+
+ if (errp != NULL)
+ *errp = err;
+
+ return data.new_threads;
+}
+
+/* Search for new threads, accessing memory through stopped thread
+ PTID. 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 (void)
+thread_db_find_new_threads_2 (thread_info *stopped, bool until_no_new)
{
- td_err_e err;
+ td_err_e err = TD_OK;
+ struct thread_db_info *info;
+ int i, loop;
+
+ info = get_thread_db_info (stopped->inf->process_target (),
+ stopped->ptid.pid ());
+
+ /* Access an lwp we know is stopped. */
+ info->proc_handle.thread = stopped;
+
+ 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);
- /* Iterate over all user-space threads to discover new threads. */
- err = td_ta_thr_iter_p (thread_agent, find_new_threads_callback, NULL,
- TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
- TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
if (err != TD_OK)
error (_("Cannot find new threads: %s"), thread_db_err_str (err));
}
-static char *
-thread_db_pid_to_str (ptid_t ptid)
+static void
+thread_db_find_new_threads_1 (thread_info *stopped)
{
- if (is_thread (ptid))
- {
- static char buf[64];
- struct thread_info *thread_info;
+ thread_db_find_new_threads_2 (stopped, 0);
+}
- thread_info = find_thread_pid (ptid);
- if (thread_info == NULL)
- snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld) (Missing)",
- GET_THREAD (ptid), GET_LWP (ptid));
- else
- snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
- GET_THREAD (ptid), GET_LWP (ptid));
+/* Implement the to_update_thread_list target method for this
+ target. */
- return buf;
+void
+thread_db_target::update_thread_list ()
+{
+ struct thread_db_info *info;
+
+ 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);
}
- if (target_beneath->to_pid_to_str (ptid))
- return target_beneath->to_pid_to_str (ptid);
+ /* Give the beneath target a chance to do extra processing. */
+ this->beneath ()->update_thread_list ();
+}
+
+std::string
+thread_db_target::pid_to_str (ptid_t ptid)
+{
+ thread_info *thread_info = find_thread_ptid (current_inferior (), ptid);
+
+ if (thread_info != NULL && thread_info->priv != NULL)
+ {
+ thread_db_thread_info *priv = get_thread_db_thread_info (thread_info);
+
+ return string_printf ("Thread 0x%lx (LWP %ld)",
+ (unsigned long) priv->tid, ptid.lwp ());
+ }
- return normal_pid_to_str (ptid);
+ return beneath ()->pid_to_str (ptid);
}
/* Return a string describing the state of the thread specified by
INFO. */
-static char *
-thread_db_extra_thread_info (struct thread_info *info)
+const char *
+thread_db_target::extra_thread_info (thread_info *info)
{
- if (info->private->dying)
+ if (info->priv == NULL)
+ return NULL;
+
+ thread_db_thread_info *priv = get_thread_db_thread_info (info);
+
+ if (priv->dying)
return "Exiting";
return NULL;
}
-/* Return 1 if this thread has the same LWP as the passed PTID. */
+/* Return pointer to the thread_info struct which corresponds to
+ THREAD_HANDLE (having length HANDLE_LEN). */
-static int
-same_ptid_callback (struct thread_info *thread, void *arg)
+thread_info *
+thread_db_target::thread_handle_to_thread_info (const gdb_byte *thread_handle,
+ int handle_len,
+ inferior *inf)
{
- ptid_t *ptid_p = arg;
+ 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));
+
+ for (thread_info *tp : inf->non_exited_threads ())
+ {
+ thread_db_thread_info *priv = get_thread_db_thread_info (tp);
- return GET_LWP (thread->ptid) == GET_LWP (*ptid_p);
+ if (priv != NULL && handle_tid == priv->tid)
+ return tp;
+ }
+
+ return NULL;
}
-/* Get the address of the thread local variable in load module LM which
- is stored at OFFSET within the thread local storage for thread PTID. */
+/* Return the thread handle associated the thread_info pointer TP. */
-static CORE_ADDR
-thread_db_get_thread_local_address (ptid_t ptid,
- CORE_ADDR lm,
- CORE_ADDR offset)
+gdb::byte_vector
+thread_db_target::thread_info_to_thread_handle (struct thread_info *tp)
{
- /* If we have not discovered any threads yet, check now. */
- if (!is_thread (ptid) && !have_threads ())
- thread_db_find_new_threads ();
+ thread_db_thread_info *priv = get_thread_db_thread_info (tp);
- /* Try to find a matching thread if we still have the LWP ID instead
- of the thread ID. */
- if (!is_thread (ptid))
- {
- struct thread_info *thread;
+ if (priv == NULL)
+ return gdb::byte_vector ();
- thread = iterate_over_threads (same_ptid_callback, &ptid);
- if (thread != NULL)
- ptid = thread->ptid;
- }
+ int handle_size = sizeof (priv->tid);
+ gdb::byte_vector rv (handle_size);
- if (is_thread (ptid))
- {
- td_err_e err;
- void *address;
- struct thread_info *thread_info;
+ 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. */
- /* 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"));
+CORE_ADDR
+thread_db_target::get_thread_local_address (ptid_t ptid,
+ CORE_ADDR lm,
+ CORE_ADDR offset)
+{
+ 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);
- gdb_assert (thread_info);
- 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_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_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. */
- observer_attach_new_objfile (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