Centralize control of contructors/destructors

[lttng-ust.git] / libust / lttng-ust-comm.c

diff --git a/libust/lttng-ust-comm.c b/libust/lttng-ust-comm.c
index 04a32676b0a0a7755b6fbc6d8392f810145e7ba8..ee187f8b9308f8d41dd50b9f76611a938506827b 100644 (file)
--- a/libust/lttng-ust-comm.c
+++ b/libust/lttng-ust-comm.c
@@ -23,15 +23,22 @@
 #include <sys/socket.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
  * by fork() to deal with removal of threads, and by exit path.
@@ -66,6 +73,7 @@ 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 */
@@ -84,6 +92,13 @@ 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)
 {
@@ -142,12 +157,17 @@ 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;
 
+       if (sock_info->constructor_sem_posted)
+               return 0;
+       sock_info->constructor_sem_posted = 1;
        ret = uatomic_add_return(&sem_count, -1);
+       fprintf(stderr, "DEC ret %d\n", ret);
        if (ret == 0) {
+               fprintf(stderr, "POST\n");
                ret = sem_post(&constructor_wait);
                assert(!ret);
        }
@@ -180,7 +200,7 @@ 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;
@@ -275,7 +295,7 @@ 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);
@@ -305,7 +325,7 @@ 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);
@@ -393,13 +413,26 @@ 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);
 
@@ -439,7 +472,7 @@ void __attribute__((constructor)) lttng_ust_comm_init(void)
        }
 }
 
-void __attribute__((destructor)) lttng_ust_comm_exit(void)
+void __attribute__((destructor)) lttng_ust_exit(void)
 {
        int ret;
 
@@ -476,4 +509,8 @@ 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();
 }