Add gid to registration
[lttng-ust.git] / libust / lttng-ust-comm.c
index 8f0cb85b95d2074c1ff2c362e69ce3de1eb7e994..6b548f82e0dcad7ba850495d555c2b7f7a6b8dc5 100644 (file)
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/prctl.h>
 #include <unistd.h>
 #include <errno.h>
-#include <ust/lttng-ust-abi.h>
-#include <lttng-ust-comm.h>
-#include <ust/usterr-signal-safe.h>
 #include <pthread.h>
 #include <semaphore.h>
 #include <time.h>
 #include <assert.h>
+#include <urcu/uatomic.h>
+
+#include <lttng-ust-comm.h>
+#include <ust/usterr-signal-safe.h>
+#include <ust/lttng-ust-abi.h>
+#include <ust/tracepoint.h>
+
+/*
+ * Has lttng ust comm constructor been called ?
+ */
+static int initialized;
 
 /*
  * communication thread mutex. Held when handling a command, also held
@@ -51,6 +60,10 @@ static int lttng_ust_comm_should_quit;
  *   daemon problems).
  */
 static sem_t constructor_wait;
+/*
+ * Doing this for both the global and local sessiond.
+ */
+static int sem_count = { 2 };
 
 /*
  * Info about socket and associated listener thread.
@@ -61,6 +74,7 @@ struct sock_info {
        int socket;
        pthread_t ust_listener; /* listener thread */
        int root_handle;
+       int constructor_sem_posted;;
 };
 
 /* Socket from app (connect) to session daemon (listen) for communication */
@@ -79,6 +93,13 @@ struct sock_info local_apps = {
        .root_handle = -1,
 };
 
+extern void ltt_ring_buffer_client_overwrite_init(void);
+extern void ltt_ring_buffer_client_discard_init(void);
+extern void ltt_ring_buffer_metadata_client_init(void);
+extern void ltt_ring_buffer_client_overwrite_exit(void);
+extern void ltt_ring_buffer_client_discard_exit(void);
+extern void ltt_ring_buffer_metadata_client_exit(void);
+
 static
 int setup_local_apps_socket(void)
 {
@@ -96,17 +117,28 @@ static
 int register_app_to_sessiond(int socket)
 {
        ssize_t ret;
+       int prctl_ret;
        struct {
                uint32_t major;
                uint32_t minor;
                pid_t pid;
+               pid_t ppid;
                uid_t uid;
+               gid_t gid;
+               char name[16];  /* process name */
        } reg_msg;
 
        reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR;
        reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR;
        reg_msg.pid = getpid();
+       reg_msg.ppid = getppid();
        reg_msg.uid = getuid();
+       reg_msg.gid = getgid();
+       prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0);
+       if (prctl_ret) {
+               ERR("Error executing prctl");
+               return -errno;
+       }
 
        ret = lttcomm_send_unix_sock(socket, &reg_msg, sizeof(reg_msg));
        if (ret >= 0 && ret != sizeof(reg_msg))
@@ -137,12 +169,18 @@ int send_reply(int sock, struct lttcomm_ust_reply *lur)
 }
 
 static
-int handle_register_done(void)
+int handle_register_done(struct sock_info *sock_info)
 {
        int ret;
 
-       ret = sem_post(&constructor_wait);
-       assert(!ret);
+       if (sock_info->constructor_sem_posted)
+               return 0;
+       sock_info->constructor_sem_posted = 1;
+       ret = uatomic_add_return(&sem_count, -1);
+       if (ret == 0) {
+               ret = sem_post(&constructor_wait);
+               assert(!ret);
+       }
        return 0;
 }
 
@@ -172,7 +210,7 @@ int handle_message(struct sock_info *sock_info,
        switch (lum->cmd) {
        case LTTNG_UST_REGISTER_DONE:
                if (lum->handle == LTTNG_UST_ROOT_HANDLE)
-                       ret = handle_register_done();
+                       ret = handle_register_done(sock_info);
                else
                        ret = -EINVAL;
                break;
@@ -267,7 +305,7 @@ restart:
                 * If we cannot find the sessiond daemon, don't delay
                 * constructor execution.
                 */
-               ret = handle_register_done();
+               ret = handle_register_done(sock_info);
                assert(!ret);
                pthread_mutex_unlock(&lttng_ust_comm_mutex);
                sleep(5);
@@ -297,7 +335,7 @@ restart:
                 * If we cannot register to the sessiond daemon, don't
                 * delay constructor execution.
                 */
-               ret = handle_register_done();
+               ret = handle_register_done(sock_info);
                assert(!ret);
                pthread_mutex_unlock(&lttng_ust_comm_mutex);
                sleep(5);
@@ -369,9 +407,9 @@ int get_timeout(struct timespec *constructor_timeout)
        if (ret) {
                return -1;
        }
-
-       constructor_timeout->tv_nsec =
-               constructor_timeout->tv_nsec + (constructor_delay_ms * 1000000UL);
+       constructor_timeout->tv_sec += constructor_delay_ms / 1000UL;
+       constructor_timeout->tv_nsec +=
+               (constructor_delay_ms % 1000UL) * 1000000UL;
        if (constructor_timeout->tv_nsec >= 1000000000UL) {
                constructor_timeout->tv_sec++;
                constructor_timeout->tv_nsec -= 1000000000UL;
@@ -385,17 +423,30 @@ int get_timeout(struct timespec *constructor_timeout)
  */
 /* TODO */
 
-void __attribute__((constructor)) lttng_ust_comm_init(void)
+void __attribute__((constructor)) lttng_ust_init(void)
 {
        struct timespec constructor_timeout;
        int timeout_mode;
        int ret;
 
+       if (uatomic_xchg(&initialized, 1) == 1)
+               return;
+
+       /*
+        * We want precise control over the order in which we construct
+        * our sub-libraries vs starting to receive commands from
+        * sessiond (otherwise leading to errors when trying to create
+        * sessiond before the init functions are completed).
+        */
        init_usterr();
+       init_tracepoint();
+       ltt_ring_buffer_metadata_client_init();
+       ltt_ring_buffer_client_overwrite_init();
+       ltt_ring_buffer_client_discard_init();
 
        timeout_mode = get_timeout(&constructor_timeout);
 
-       ret = sem_init(&constructor_wait, 0, 2);
+       ret = sem_init(&constructor_wait, 0, 0);
        assert(!ret);
 
        ret = setup_local_apps_socket();
@@ -403,13 +454,6 @@ void __attribute__((constructor)) lttng_ust_comm_init(void)
                ERR("Error setting up to local apps socket");
        }
 
-       /*
-        * Wait for the pthread cond to let us continue to main program
-        * execution. Hold mutex across thread creation, so we start
-        * waiting for the condition before the threads can signal its
-        * completion.
-        */
-       pthread_mutex_lock(&lttng_ust_comm_mutex);
        ret = pthread_create(&global_apps.ust_listener, NULL,
                        ust_listener_thread, &global_apps);
        ret = pthread_create(&local_apps.ust_listener, NULL,
@@ -417,24 +461,28 @@ void __attribute__((constructor)) lttng_ust_comm_init(void)
 
        switch (timeout_mode) {
        case 1: /* timeout wait */
-               ret = sem_timedwait(&constructor_wait, &constructor_timeout);
+               do {
+                       ret = sem_timedwait(&constructor_wait,
+                                       &constructor_timeout);
+               } while (ret < 0 && errno == EINTR);
                if (ret < 0 && errno == ETIMEDOUT) {
                        ERR("Timed out waiting for ltt-sessiond");
                } else {
                        assert(!ret);
                }
                break;
-       case 0: /* wait forever */
-               ret = sem_wait(&constructor_wait);
+       case -1:/* wait forever */
+               do {
+                       ret = sem_wait(&constructor_wait);
+               } while (ret < 0 && errno == EINTR);
                assert(!ret);
                break;
-       case -1:/* no timeout */
+       case 0: /* no timeout */
                break;
        }
-       pthread_mutex_unlock(&lttng_ust_comm_mutex);
 }
 
-void __attribute__((destructor)) lttng_ust_comm_exit(void)
+void __attribute__((destructor)) lttng_ust_exit(void)
 {
        int ret;
 
@@ -471,4 +519,8 @@ void __attribute__((destructor)) lttng_ust_comm_exit(void)
 
        lttng_ust_abi_exit();
        ltt_events_exit();
+       ltt_ring_buffer_client_discard_exit();
+       ltt_ring_buffer_client_overwrite_exit();
+       ltt_ring_buffer_metadata_client_exit();
+       exit_tracepoint();
 }
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