Remove the timeout on poll
[lttng-tools.git] / kconsumerd / kconsumerd.c
index 315095ee3c102794817176262d096e1b21089b96..fcd4101a62d0bdbdff1b7ffcd34a86365324afbf 100644 (file)
@@ -61,6 +61,9 @@ static pthread_t threads[2];
 /* communication with splice */
 static int thread_pipe[2];
 
+/* pipe to wake the poll thread when necessary */
+static int poll_pipe[2];
+
 /* socket to communicate errors with sessiond */
 static int error_socket = -1;
 
@@ -79,6 +82,7 @@ static char error_sock_path[PATH_MAX]; /* Global error path */
  */
 static void del_fd(struct ltt_kconsumerd_fd *lcf)
 {
+       DBG("Removing %d", lcf->consumerd_fd);
        pthread_mutex_lock(&kconsumerd_lock_fds);
        cds_list_del(&lcf->list);
        if (fds_count > 0) {
@@ -103,7 +107,6 @@ static void cleanup()
 {
        struct ltt_kconsumerd_fd *iter;
 
-
        /* remove the socket file */
        unlink(command_sock_path);
 
@@ -118,7 +121,8 @@ static void cleanup()
        }
 }
 
-/* send_error
+/*
+ * send_error
  *
  * send return code to ltt-sessiond
  */
@@ -330,7 +334,7 @@ static int read_subbuffer(struct ltt_kconsumerd_fd *kconsumerd_fd)
        long ret = 0;
        int infd = kconsumerd_fd->consumerd_fd;
 
-       DBG("In read_subbuffer");
+       DBG("In read_subbuffer (infd : %d)", infd);
        /* Get the next subbuffer */
        err = kernctl_get_next_subbuf(infd);
        if (err != 0) {
@@ -403,7 +407,7 @@ static int consumerd_recv_fd(int sfd, int size,
 {
        struct msghdr msg;
        struct iovec iov[1];
-       int ret, i;
+       int ret, i, tmp2;
        struct cmsghdr *cmsg;
        int nb_fd;
        char tmp[CMSG_SPACE(size)];
@@ -464,7 +468,8 @@ static int consumerd_recv_fd(int sfd, int size,
                }
                /* flag to tell the polling thread to update its fd array */
                update_fd_array = 1;
-               send_error(KCONSUMERD_SUCCESS_RECV_FD);
+               /* signal the poll thread */
+               tmp2 = write(poll_pipe[1], "4", 1);
        } else {
                ERR("Didn't received any fd");
                send_error(KCONSUMERD_ERROR_RECV_FD);
@@ -511,30 +516,28 @@ static void *thread_receive_fds(void *data)
                goto error;
        }
 
+       /* Blocking call, waiting for transmission */
+       sock = lttcomm_accept_unix_sock(client_socket);
+       if (sock <= 0) {
+               WARN("On accept, retrying");
+               goto error;
+       }
        while (1) {
-               /* Blocking call, waiting for transmission */
-               sock = lttcomm_accept_unix_sock(client_socket);
-               if (sock <= 0) {
-                       WARN("On accept, retrying");
-                       continue;
-               }
-
                /* We first get the number of fd we are about to receive */
                ret = lttcomm_recv_unix_sock(sock, &tmp,
                                sizeof(struct lttcomm_kconsumerd_header));
-               if (ret < 0) {
+               if (ret <= 0) {
                        ERR("Receiving the lttcomm_kconsumerd_header, exiting");
                        goto error;
                }
                ret = consumerd_recv_fd(sock, tmp.payload_size, tmp.cmd_type);
-               if (ret < 0) {
+               if (ret <= 0) {
                        ERR("Receiving the FD, exiting");
                        goto error;
                }
        }
 
 error:
-       cleanup();
        return NULL;
 }
 
@@ -562,13 +565,15 @@ static int update_poll_array(struct pollfd **pollfd,
                *local_kconsumerd_fd = NULL;
        }
 
-       *pollfd = malloc(fds_count * sizeof(struct pollfd));
+       /* allocate for all fds + 1 for the poll_pipe */
+       *pollfd = malloc((fds_count + 1) * sizeof(struct pollfd));
        if (*pollfd == NULL) {
                perror("pollfd malloc");
                goto error_mem;
        }
 
-       *local_kconsumerd_fd = malloc(fds_count * sizeof(struct ltt_kconsumerd_fd));
+       /* allocate for all fds + 1 for the poll_pipe */
+       *local_kconsumerd_fd = malloc((fds_count + 1) * sizeof(struct ltt_kconsumerd_fd));
        if (*local_kconsumerd_fd == NULL) {
                perror("local_kconsumerd_fd malloc");
                goto error_mem;
@@ -581,14 +586,21 @@ static int update_poll_array(struct pollfd **pollfd,
                DBG("Inside for each");
                if (iter->state == ACTIVE_FD) {
                        DBG("Active FD %d", iter->consumerd_fd);
-                       pollfd[i]->fd = iter->consumerd_fd;
-                       pollfd[i]->events = POLLIN | POLLPRI;
+                       (*pollfd)[i].fd = iter->consumerd_fd;
+                       (*pollfd)[i].events = POLLIN | POLLPRI;
                        local_kconsumerd_fd[i] = iter;
                        i++;
                } else if (iter->state == DELETE_FD) {
                        del_fd(iter);
                }
        }
+       /*
+        * insert the poll_pipe at the end of the array and don't increment i
+        * so nb_fd is the number of real FD
+        */
+       (*pollfd)[i].fd = poll_pipe[0];
+       (*pollfd)[i].events = POLLIN;
+
        update_fd_array = 0;
        pthread_mutex_unlock(&kconsumerd_lock_fds);
        return i;
@@ -608,9 +620,11 @@ static void *thread_poll_fds(void *data)
        int num_rdy, num_hup, high_prio, ret, i;
        struct pollfd *pollfd = NULL;
        /* local view of the fds */
-       struct ltt_kconsumerd_fd *local_kconsumerd_fd = NULL;
+       struct ltt_kconsumerd_fd **local_kconsumerd_fd = NULL;
        /* local view of fds_count */
        int nb_fd = 0;
+       char tmp;
+       int tmp2;
 
        ret = pipe(thread_pipe);
        if (ret < 0) {
@@ -618,6 +632,8 @@ static void *thread_poll_fds(void *data)
                goto end;
        }
 
+       local_kconsumerd_fd = malloc(sizeof(struct ltt_kconsumerd_fd));
+
        while (1) {
                high_prio = 0;
                num_hup = 0;
@@ -627,7 +643,7 @@ static void *thread_poll_fds(void *data)
                 * local array as well
                 */
                if (update_fd_array) {
-                       ret = update_poll_array(&pollfd, &local_kconsumerd_fd);
+                       ret = update_poll_array(&pollfd, local_kconsumerd_fd);
                        if (ret < 0) {
                                ERR("Error in allocating pollfd or local_outfds");
                                send_error(KCONSUMERD_POLL_ERROR);
@@ -637,8 +653,8 @@ static void *thread_poll_fds(void *data)
                }
 
                /* poll on the array of fds */
-               DBG("polling on %d fd", nb_fd);
-               num_rdy = poll(pollfd, nb_fd, POLL_TIMEOUT);
+               DBG("polling on %d fd", nb_fd + 1);
+               num_rdy = poll(pollfd, nb_fd + 1, -1);
                DBG("poll num_rdy : %d", num_rdy);
                if (num_rdy == -1) {
                        perror("Poll error");
@@ -646,6 +662,16 @@ static void *thread_poll_fds(void *data)
                        goto end;
                }
 
+               /*
+                * if only the poll_pipe triggered poll to return just return to the
+                * beginning of the loop to update the array
+                */
+               if (num_rdy == 1 && pollfd[nb_fd].revents == POLLIN) {
+                       DBG("poll_pipe wake up");
+                       tmp2 = read(poll_pipe[0], &tmp, 1);
+                       continue;
+               }
+
                /* Take care of high priority channels first. */
                for (i = 0; i < nb_fd; i++) {
                        switch(pollfd[i].revents) {
@@ -666,7 +692,7 @@ static void *thread_poll_fds(void *data)
                                case POLLPRI:
                                        DBG("Urgent read on fd %d", pollfd[i].fd);
                                        high_prio = 1;
-                                       ret = read_subbuffer(&local_kconsumerd_fd[i]);
+                                       ret = read_subbuffer(local_kconsumerd_fd[i]);
                                        /* it's ok to have an unavailable sub-buffer (FIXME : is it ?) */
                                        if (ret == EAGAIN) {
                                                ret = 0;
@@ -679,7 +705,7 @@ static void *thread_poll_fds(void *data)
                if (nb_fd > 0 && num_hup == nb_fd) {
                        DBG("every buffer FD has hung up\n");
                        send_error(KCONSUMERD_POLL_HUP);
-                       continue;
+                       goto end;
                }
 
                /* Take care of low priority channels. */
@@ -688,7 +714,7 @@ static void *thread_poll_fds(void *data)
                                switch(pollfd[i].revents) {
                                        case POLLIN:
                                                DBG("Normal read on fd %d", pollfd[i].fd);
-                                               ret = read_subbuffer(&local_kconsumerd_fd[i]);
+                                               ret = read_subbuffer(local_kconsumerd_fd[i]);
                                                /* it's ok to have an unavailable subbuffer (FIXME : is it ?) */
                                                if (ret == EAGAIN) {
                                                        ret = 0;
@@ -829,6 +855,13 @@ int main(int argc, char **argv)
                goto error;
        }
 
+       /* create the pipe to wake to polling thread when needed */
+       ret = pipe(poll_pipe);
+       if (ret < 0) {
+               perror("Error creating poll pipe");
+               goto end;
+       }
+
        /* Connect to the socket created by ltt-sessiond to report errors */
        DBG("Connecting to error socket %s", error_sock_path);
        error_socket = lttcomm_connect_unix_sock(error_sock_path);
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