Add lttng_ust prefix before struct obj and struct objd_ops
[lttng-ust.git] / libust / lttng-ust-comm.c
index 93f48940edb9a162f205686b066f1f9eb9bbc4e9..3ab7ca7c2b69341b13b8f2a0b69244c92220379f 100644 (file)
@@ -19,6 +19,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#define _LGPL_SOURCE
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/prctl.h>
 #include <assert.h>
 #include <signal.h>
 #include <urcu/uatomic.h>
+#include <urcu/futex.h>
 
 #include <lttng-ust-comm.h>
+#include <ust/lttng-events.h>
 #include <ust/usterr-signal-safe.h>
 #include <ust/lttng-ust-abi.h>
 #include <ust/tracepoint.h>
@@ -117,6 +120,8 @@ struct sock_info local_apps = {
        .socket = -1,
 };
 
+static int wait_poll_fallback;
+
 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);
@@ -177,18 +182,18 @@ int register_app_to_sessiond(int socket)
                return -errno;
        }
 
-       ret = lttcomm_send_unix_sock(socket, &reg_msg, sizeof(reg_msg));
+       ret = ustcomm_send_unix_sock(socket, &reg_msg, sizeof(reg_msg));
        if (ret >= 0 && ret != sizeof(reg_msg))
                return -EIO;
        return ret;
 }
 
 static
-int send_reply(int sock, struct lttcomm_ust_reply *lur)
+int send_reply(int sock, struct ustcomm_ust_reply *lur)
 {
        ssize_t len;
 
-       len = lttcomm_send_unix_sock(sock, lur, sizeof(*lur));
+       len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur));
        switch (len) {
        case sizeof(*lur):
                DBG("message successfully sent");
@@ -213,6 +218,9 @@ int handle_register_done(struct sock_info *sock_info)
        if (sock_info->constructor_sem_posted)
                return 0;
        sock_info->constructor_sem_posted = 1;
+       if (uatomic_read(&sem_count) <= 0) {
+               return 0;
+       }
        ret = uatomic_add_return(&sem_count, -1);
        if (ret == 0) {
                ret = sem_post(&constructor_wait);
@@ -223,11 +231,12 @@ int handle_register_done(struct sock_info *sock_info)
 
 static
 int handle_message(struct sock_info *sock_info,
-               int sock, struct lttcomm_ust_msg *lum)
+               int sock, struct ustcomm_ust_msg *lum)
 {
        int ret = 0;
-       const struct objd_ops *ops;
-       struct lttcomm_ust_reply lur;
+       const struct lttng_ust_objd_ops *ops;
+       struct ustcomm_ust_reply lur;
+       int shm_fd, wait_fd;
 
        ust_lock();
 
@@ -271,12 +280,58 @@ end:
        lur.cmd = lum->cmd;
        lur.ret_val = ret;
        if (ret >= 0) {
-               lur.ret_code = LTTCOMM_OK;
+               lur.ret_code = USTCOMM_OK;
        } else {
-               lur.ret_code = LTTCOMM_SESSION_FAIL;
+               //lur.ret_code = USTCOMM_SESSION_FAIL;
+               lur.ret_code = ret;
+       }
+       switch (lum->cmd) {
+       case LTTNG_UST_STREAM:
+               /*
+                * Special-case reply to send stream info.
+                * Use lum.u output.
+                */
+               lur.u.stream.memory_map_size = lum->u.stream.memory_map_size;
+               shm_fd = lum->u.stream.shm_fd;
+               wait_fd = lum->u.stream.wait_fd;
+               break;
+       case LTTNG_UST_METADATA:
+       case LTTNG_UST_CHANNEL:
+               lur.u.channel.memory_map_size = lum->u.channel.memory_map_size;
+               shm_fd = lum->u.channel.shm_fd;
+               wait_fd = lum->u.channel.wait_fd;
+               break;
+       case LTTNG_UST_VERSION:
+               lur.u.version = lum->u.version;
+               break;
        }
        ret = send_reply(sock, &lur);
+       if (ret < 0) {
+               perror("error sending reply");
+               goto error;
+       }
 
+       if ((lum->cmd == LTTNG_UST_STREAM
+            || lum->cmd == LTTNG_UST_CHANNEL
+            || lum->cmd == LTTNG_UST_METADATA)
+                       && lur.ret_code == USTCOMM_OK) {
+               /* we also need to send the file descriptors. */
+               ret = ustcomm_send_fds_unix_sock(sock,
+                       &shm_fd, &shm_fd,
+                       1, sizeof(int));
+               if (ret < 0) {
+                       perror("send shm_fd");
+                       goto error;
+               }
+               ret = ustcomm_send_fds_unix_sock(sock,
+                       &wait_fd, &wait_fd,
+                       1, sizeof(int));
+               if (ret < 0) {
+                       perror("send wait_fd");
+                       goto error;
+               }
+       }
+error:
        ust_unlock();
        return ret;
 }
@@ -477,10 +532,15 @@ error:
 static
 void wait_for_sessiond(struct sock_info *sock_info)
 {
+       int ret;
+
        ust_lock();
        if (lttng_ust_comm_should_quit) {
                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)
@@ -489,9 +549,23 @@ void wait_for_sessiond(struct sock_info *sock_info)
        ust_unlock();
 
        DBG("Waiting for %s apps sessiond", sock_info->name);
-       /* Wait for futex wakeup TODO */
-       sleep(5);
-
+       /* Wait for futex wakeup */
+       if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) {
+               ret = futex_async((int32_t *) sock_info->wait_shm_mmap,
+                       FUTEX_WAIT, 0, NULL, NULL, 0);
+               if (ret < 0) {
+                       if (errno == EFAULT) {
+                               wait_poll_fallback = 1;
+                               WARN(
+"Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
+"do not support FUTEX_WAKE on read-only memory mappings correctly. "
+"Please upgrade your kernel "
+"(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
+"mainline). LTTng-UST will use polling mode fallback.");
+                       }
+                       PERROR("futex");
+               }
+       }
        return;
 
 quit:
@@ -500,8 +574,6 @@ quit:
 
 error:
        ust_unlock();
-       /* Error handling: fallback on a 5 seconds sleep. */
-       sleep(5);
        return;
 }
 
@@ -516,10 +588,25 @@ static
 void *ust_listener_thread(void *arg)
 {
        struct sock_info *sock_info = arg;
-       int sock, ret;
+       int sock, ret, prev_connect_failed = 0, has_waited = 0;
 
        /* Restart trying to connect to the session daemon */
 restart:
+       if (prev_connect_failed) {
+               /* Wait for sessiond availability with pipe */
+               wait_for_sessiond(sock_info);
+               if (has_waited) {
+                       has_waited = 0;
+                       /*
+                        * Sleep for 5 seconds before retrying after a
+                        * sequence of failure / wait / failure. This
+                        * deals with a killed or broken session daemon.
+                        */
+                       sleep(5);
+               }
+               has_waited = 1;
+               prev_connect_failed = 0;
+       }
        ust_lock();
 
        if (lttng_ust_comm_should_quit) {
@@ -536,9 +623,10 @@ restart:
        }
 
        /* Register */
-       ret = lttcomm_connect_unix_sock(sock_info->sock_path);
+       ret = ustcomm_connect_unix_sock(sock_info->sock_path);
        if (ret < 0) {
                ERR("Error connecting to %s apps socket", sock_info->name);
+               prev_connect_failed = 1;
                /*
                 * If we cannot find the sessiond daemon, don't delay
                 * constructor execution.
@@ -546,9 +634,6 @@ restart:
                ret = handle_register_done(sock_info);
                assert(!ret);
                ust_unlock();
-
-               /* Wait for sessiond availability with pipe */
-               wait_for_sessiond(sock_info);
                goto restart;
        }
 
@@ -560,7 +645,7 @@ restart:
         */
        if (sock_info->root_handle == -1) {
                ret = lttng_abi_create_root_handle();
-               if (ret) {
+               if (ret < 0) {
                        ERR("Error creating root handle");
                        ust_unlock();
                        goto quit;
@@ -571,6 +656,7 @@ restart:
        ret = register_app_to_sessiond(sock);
        if (ret < 0) {
                ERR("Error registering to %s apps socket", sock_info->name);
+               prev_connect_failed = 1;
                /*
                 * If we cannot register to the sessiond daemon, don't
                 * delay constructor execution.
@@ -578,16 +664,15 @@ restart:
                ret = handle_register_done(sock_info);
                assert(!ret);
                ust_unlock();
-               wait_for_sessiond(sock_info);
                goto restart;
        }
        ust_unlock();
 
        for (;;) {
                ssize_t len;
-               struct lttcomm_ust_msg lum;
+               struct ustcomm_ust_msg lum;
 
-               len = lttcomm_recv_unix_sock(sock, &lum, sizeof(lum));
+               len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum));
                switch (len) {
                case 0: /* orderly shutdown */
                        DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name);
@@ -734,7 +819,7 @@ void lttng_ust_cleanup(int exiting)
                cleanup_sock_info(&local_apps);
        }
        lttng_ust_abi_exit();
-       ltt_events_exit();
+       lttng_ust_events_exit();
        ltt_ring_buffer_client_discard_exit();
        ltt_ring_buffer_client_overwrite_exit();
        ltt_ring_buffer_metadata_client_exit();
@@ -843,6 +928,7 @@ void ust_after_fork_child(ust_fork_info_t *fork_info)
        /* Release urcu mutexes */
        rcu_bp_after_fork_child();
        lttng_ust_cleanup(0);
+       lttng_context_vtid_reset();
        /* Release mutexes and reenable signals */
        ust_after_fork_common(fork_info);
        lttng_ust_init();
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