Move wait_shm_mmap initialization to library constructor
[lttng-ust.git] / liblttng-ust / lttng-ust-comm.c
index 511b9cf4a88214c0225ff8a7e15a63cbca32145e..faea043d13124df27a152b438da4f6f16ef984a2 100644 (file)
@@ -260,7 +260,7 @@ struct sock_info global_apps = {
        .global = 1,
 
        .root_handle = -1,
-       .allowed = 1,
+       .allowed = 0,
        .thread_active = 0,
 
        .sock_path = LTTNG_DEFAULT_RUNDIR "/" LTTNG_UST_SOCK_FILENAME,
@@ -339,6 +339,8 @@ extern void lttng_ring_buffer_client_discard_exit(void);
 extern void lttng_ring_buffer_client_discard_rt_exit(void);
 extern void lttng_ring_buffer_metadata_client_exit(void);
 
+static char *get_map_shm(struct sock_info *sock_info);
+
 ssize_t lttng_ust_read(int fd, void *buf, size_t len)
 {
        ssize_t ret;
@@ -430,25 +432,48 @@ void print_cmd(int cmd, int handle)
                lttng_ust_obj_get_name(handle), handle);
 }
 
+static
+int setup_global_apps(void)
+{
+       int ret = 0;
+       assert(!global_apps.wait_shm_mmap);
+
+       global_apps.wait_shm_mmap = get_map_shm(&global_apps);
+       if (!global_apps.wait_shm_mmap) {
+               WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
+               global_apps.allowed = 0;
+               ret = -EIO;
+               goto error;
+       }
+
+       global_apps.allowed = 1;
+error:
+       return ret;
+}
 static
 int setup_local_apps(void)
 {
+       int ret = 0;
        const char *home_dir;
        uid_t uid;
 
+       assert(!local_apps.wait_shm_mmap);
+
        uid = getuid();
        /*
         * Disallow per-user tracing for setuid binaries.
         */
        if (uid != geteuid()) {
                assert(local_apps.allowed == 0);
-               return 0;
+               ret = 0;
+               goto end;
        }
        home_dir = get_lttng_home_dir();
        if (!home_dir) {
                WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
                assert(local_apps.allowed == 0);
-               return -ENOENT;
+               ret = -ENOENT;
+               goto end;
        }
        local_apps.allowed = 1;
        snprintf(local_apps.sock_path, PATH_MAX, "%s/%s/%s",
@@ -458,7 +483,16 @@ int setup_local_apps(void)
        snprintf(local_apps.wait_shm_path, PATH_MAX, "/%s-%u",
                LTTNG_UST_WAIT_FILENAME,
                uid);
-       return 0;
+
+       local_apps.wait_shm_mmap = get_map_shm(&local_apps);
+       if (!local_apps.wait_shm_mmap) {
+               WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
+               local_apps.allowed = 0;
+               ret = -EIO;
+               goto end;
+       }
+end:
+       return ret;
 }
 
 /*
@@ -1261,7 +1295,18 @@ char *get_map_shm(struct sock_info *sock_info)
                lttng_ust_unlock_fd_tracker();
                goto error;
        }
-       lttng_ust_add_fd_to_tracker(wait_shm_fd);
+
+       ret = lttng_ust_add_fd_to_tracker(wait_shm_fd);
+       if (ret < 0) {
+               ret = close(wait_shm_fd);
+               if (!ret) {
+                       PERROR("Error closing fd");
+               }
+               lttng_ust_unlock_fd_tracker();
+               goto error;
+       }
+
+       wait_shm_fd = ret;
        lttng_ust_unlock_fd_tracker();
 
        wait_shm_mmap = mmap(NULL, page_size, PROT_READ,
@@ -1290,19 +1335,17 @@ error:
 static
 void wait_for_sessiond(struct sock_info *sock_info)
 {
+       /* Use ust_lock to check if we should quit. */
        if (ust_lock()) {
                goto quit;
        }
        if (wait_poll_fallback) {
                goto error;
        }
-       if (!sock_info->wait_shm_mmap) {
-               sock_info->wait_shm_mmap = get_map_shm(sock_info);
-               if (!sock_info->wait_shm_mmap)
-                       goto error;
-       }
        ust_unlock();
 
+       assert(sock_info->wait_shm_mmap);
+
        DBG("Waiting for %s apps sessiond", sock_info->name);
        /* Wait for futex wakeup */
        if (uatomic_read((int32_t *) sock_info->wait_shm_mmap))
@@ -1353,7 +1396,7 @@ static
 void *ust_listener_thread(void *arg)
 {
        struct sock_info *sock_info = arg;
-       int sock, ret, prev_connect_failed = 0, has_waited = 0;
+       int sock, ret, prev_connect_failed = 0, has_waited = 0, fd;
        long timeout;
 
        lttng_ust_fixup_tls();
@@ -1385,6 +1428,10 @@ restart:
                prev_connect_failed = 0;
        }
 
+       if (ust_lock()) {
+               goto quit;
+       }
+
        if (sock_info->socket != -1) {
                /* FD tracker is updated by ustcomm_close_unix_sock() */
                ret = ustcomm_close_unix_sock(sock_info->socket);
@@ -1404,9 +1451,6 @@ restart:
                sock_info->notify_socket = -1;
        }
 
-       if (ust_lock()) {
-               goto quit;
-       }
 
        /*
         * Register. We need to perform both connect and sending
@@ -1433,9 +1477,21 @@ restart:
                ust_unlock();
                goto restart;
        }
-       lttng_ust_add_fd_to_tracker(ret);
-       lttng_ust_unlock_fd_tracker();
+       fd = ret;
+       ret = lttng_ust_add_fd_to_tracker(fd);
+       if (ret < 0) {
+               ret = close(fd);
+               if (ret) {
+                       PERROR("close on sock_info->socket");
+               }
+               ret = -1;
+               lttng_ust_unlock_fd_tracker();
+               ust_unlock();
+               goto quit;
+       }
+
        sock_info->socket = ret;
+       lttng_ust_unlock_fd_tracker();
 
        ust_unlock();
        /*
@@ -1504,9 +1560,22 @@ restart:
                ust_unlock();
                goto restart;
        }
-       lttng_ust_add_fd_to_tracker(ret);
-       lttng_ust_unlock_fd_tracker();
+
+       fd = ret;
+       ret = lttng_ust_add_fd_to_tracker(fd);
+       if (ret < 0) {
+               ret = close(fd);
+               if (ret) {
+                       PERROR("close on sock_info->notify_socket");
+               }
+               ret = -1;
+               lttng_ust_unlock_fd_tracker();
+               ust_unlock();
+               goto quit;
+       }
+
        sock_info->notify_socket = ret;
+       lttng_ust_unlock_fd_tracker();
 
        ust_unlock();
        /*
@@ -1694,8 +1763,15 @@ void __attribute__((constructor)) lttng_ust_init(void)
                PERROR("sem_init");
        }
 
+       ret = setup_global_apps();
+       if (ret) {
+               assert(global_apps.allowed == 0);
+               DBG("global apps setup returned %d", ret);
+       }
+
        ret = setup_local_apps();
        if (ret) {
+               assert(local_apps.allowed == 0);
                DBG("local apps setup returned %d", ret);
        }
 
@@ -1719,14 +1795,18 @@ void __attribute__((constructor)) lttng_ust_init(void)
                ERR("pthread_attr_setdetachstate: %s", strerror(ret));
        }
 
-       pthread_mutex_lock(&ust_exit_mutex);
-       ret = pthread_create(&global_apps.ust_listener, &thread_attr,
-                       ust_listener_thread, &global_apps);
-       if (ret) {
-               ERR("pthread_create global: %s", strerror(ret));
+       if (global_apps.allowed) {
+               pthread_mutex_lock(&ust_exit_mutex);
+               ret = pthread_create(&global_apps.ust_listener, &thread_attr,
+                               ust_listener_thread, &global_apps);
+               if (ret) {
+                       ERR("pthread_create global: %s", strerror(ret));
+               }
+               global_apps.thread_active = 1;
+               pthread_mutex_unlock(&ust_exit_mutex);
+       } else {
+               handle_register_done(&global_apps);
        }
-       global_apps.thread_active = 1;
-       pthread_mutex_unlock(&ust_exit_mutex);
 
        if (local_apps.allowed) {
                pthread_mutex_lock(&ust_exit_mutex);
@@ -1797,6 +1877,7 @@ void lttng_ust_cleanup(int exiting)
        cleanup_sock_info(&global_apps, exiting);
        cleanup_sock_info(&local_apps, exiting);
        local_apps.allowed = 0;
+       global_apps.allowed = 0;
        /*
         * The teardown in this function all affect data structures
         * accessed under the UST lock by the listener thread. This
@@ -1949,7 +2030,9 @@ void ust_after_fork_child(sigset_t *restore_sigset)
 {
        if (URCU_TLS(lttng_ust_nest_count))
                return;
+       lttng_context_vpid_reset();
        lttng_context_vtid_reset();
+       lttng_context_procname_reset();
        DBG("process %d", getpid());
        /* Release urcu mutexes */
        rcu_bp_after_fork_child();
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