+}
+
+static int
+try_thread_db_load_1 (void *handle)
+{
+ td_err_e err;
+ struct thread_db tdb;
+ struct process_info *proc = current_process ();
+
+ if (proc->private->thread_db != NULL)
+ fatal ("unexpected: proc->private->thread_db != NULL");
+
+ tdb.handle = handle;
+
+ /* Initialize pointers to the dynamic library functions we will use.
+ Essential functions first. */
+
+#define CHK(required, a) \
+ do \
+ { \
+ if ((a) == NULL) \
+ { \
+ if (debug_threads) \
+ fprintf (stderr, "dlsym: %s\n", dlerror ()); \
+ if (required) \
+ return 0; \
+ } \
+ } \
+ while (0)
+
+ CHK (1, tdb.td_ta_new_p = dlsym (handle, "td_ta_new"));
+
+ /* Attempt to open a connection to the thread library. */
+ err = tdb.td_ta_new_p (&tdb.proc_handle, &tdb.thread_agent);
+ if (err != TD_OK)
+ {
+ if (debug_threads)
+ fprintf (stderr, "td_ta_new(): %s\n", thread_db_err_str (err));
+ return 0;
+ }
+
+ CHK (1, tdb.td_ta_map_lwp2thr_p = dlsym (handle, "td_ta_map_lwp2thr"));
+ CHK (1, tdb.td_thr_get_info_p = dlsym (handle, "td_thr_get_info"));
+ CHK (1, tdb.td_ta_thr_iter_p = dlsym (handle, "td_ta_thr_iter"));
+ CHK (1, tdb.td_symbol_list_p = dlsym (handle, "td_symbol_list"));
+
+ /* This is required only when thread_db_use_events is on. */
+ CHK (thread_db_use_events,
+ tdb.td_thr_event_enable_p = dlsym (handle, "td_thr_event_enable"));
+
+ /* These are not essential. */
+ CHK (0, tdb.td_ta_event_addr_p = dlsym (handle, "td_ta_event_addr"));
+ CHK (0, tdb.td_ta_set_event_p = dlsym (handle, "td_ta_set_event"));
+ CHK (0, tdb.td_ta_event_getmsg_p = dlsym (handle, "td_ta_event_getmsg"));
+ CHK (0, tdb.td_thr_tls_get_addr_p = dlsym (handle, "td_thr_tls_get_addr"));
+
+#undef CHK
+
+ proc->private->thread_db = xmalloc (sizeof (tdb));
+ memcpy (proc->private->thread_db, &tdb, sizeof (tdb));
+
+ return 1;
+}
+
+/* Lookup a library in which given symbol resides.
+ Note: this is looking in the GDBSERVER process, not in the inferior.
+ Returns library name, or NULL. */
+
+static const char *
+dladdr_to_soname (const void *addr)
+{
+ Dl_info info;
+
+ if (dladdr (addr, &info) != 0)
+ return info.dli_fname;
+ return NULL;
+}
+
+static int
+try_thread_db_load (const char *library)
+{
+ void *handle;
+
+ if (debug_threads)
+ fprintf (stderr, "Trying host libthread_db library: %s.\n",
+ library);
+ handle = dlopen (library, RTLD_NOW);
+ if (handle == NULL)
+ {
+ if (debug_threads)
+ fprintf (stderr, "dlopen failed: %s.\n", dlerror ());
+ return 0;
+ }
+
+ if (debug_threads && 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 (stderr, "Host %s resolved to: %s.\n",
+ library, libpath);
+ }
+ }
+
+ if (try_thread_db_load_1 (handle))
+ return 1;
+
+ /* This library "refused" to work on current inferior. */
+ dlclose (handle);
+ return 0;
+}
+
+static int
+thread_db_load_search (void)
+{
+ char path[PATH_MAX];
+ const char *search_path;
+ int rc = 0;
+
+ if (libthread_db_search_path == NULL)
+ libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
+
+ search_path = libthread_db_search_path;
+ while (*search_path)
+ {
+ const char *end = strchr (search_path, ':');
+ if (end)
+ {
+ size_t len = end - search_path;
+ if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path))
+ {
+ char *cp = xmalloc (len + 1);
+ memcpy (cp, search_path, len);
+ cp[len] = '\0';
+ warning ("libthread_db_search_path component too long, "
+ "ignored: %s.", cp);
+ free (cp);
+ search_path += len + 1;
+ continue;
+ }
+ memcpy (path, search_path, len);
+ path[len] = '\0';
+ search_path += len + 1;
+ }
+ else
+ {
+ size_t len = strlen (search_path);
+
+ if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path))
+ {
+ warning ("libthread_db_search_path component too long,"
+ " ignored: %s.", search_path);
+ break;
+ }
+ memcpy (path, search_path, len + 1);
+ search_path += len;
+ }
+ strcat (path, "/");
+ strcat (path, LIBTHREAD_DB_SO);
+ if (debug_threads)
+ fprintf (stderr, "thread_db_load_search trying %s\n", path);
+ if (try_thread_db_load (path))
+ {
+ rc = 1;
+ break;
+ }
+ }
+ if (rc == 0)
+ rc = try_thread_db_load (LIBTHREAD_DB_SO);
+
+ if (debug_threads)
+ fprintf (stderr, "thread_db_load_search returning %d\n", rc);
+ return rc;