Don't quit when all FD hang up
[lttng-tools.git] / kconsumerd / kconsumerd.c
index adc1f1beddeb79b68796258289cea9edf2e532e1..5a1fe89a77cbd6772722cf45dbbab5f67732ef1e 100644 (file)
@@ -70,6 +70,9 @@ static int error_socket = -1;
 /* to count the number of time the user pressed ctrl+c */
 static int sigintcount = 0;
 
+/* flag to inform the polling thread to quit when all fd hung up */
+static int quit = 0;
+
 /* Argument variables */
 int opt_quiet;
 int opt_verbose;
@@ -312,18 +315,18 @@ static int on_read_subbuffer(struct ltt_kconsumerd_fd *kconsumerd_fd,
 splice_error:
        /* send the appropriate error description to sessiond */
        switch(ret) {
-               case EBADF:
-                       send_error(KCONSUMERD_SPLICE_EBADF);
-                       break;
-               case EINVAL:
-                       send_error(KCONSUMERD_SPLICE_EINVAL);
-                       break;
-               case ENOMEM:
-                       send_error(KCONSUMERD_SPLICE_ENOMEM);
-                       break;
-               case ESPIPE:
-                       send_error(KCONSUMERD_SPLICE_ESPIPE);
-                       break;
+       case EBADF:
+               send_error(KCONSUMERD_SPLICE_EBADF);
+               break;
+       case EINVAL:
+               send_error(KCONSUMERD_SPLICE_EINVAL);
+               break;
+       case ENOMEM:
+               send_error(KCONSUMERD_SPLICE_ENOMEM);
+               break;
+       case ESPIPE:
+               send_error(KCONSUMERD_SPLICE_ESPIPE);
+               break;
        }
 
 end:
@@ -392,7 +395,7 @@ end:
  * Update a fd according to what we just received
  */
 static void change_fd_state(int sessiond_fd,
-               enum lttcomm_kconsumerd_fd_state state)
+               enum kconsumerd_fd_state state)
 {
        struct ltt_kconsumerd_fd *iter;
        cds_list_for_each_entry(iter, &kconsumerd_fd_list.head, list) {
@@ -411,7 +414,7 @@ static void change_fd_state(int sessiond_fd,
  * Returns the size of received data
  */
 static int consumerd_recv_fd(int sfd, int size,
-               enum lttcomm_consumerd_command cmd_type)
+               enum kconsumerd_command cmd_type)
 {
        struct msghdr msg;
        struct iovec iov[1];
@@ -459,19 +462,19 @@ static int consumerd_recv_fd(int sfd, int size,
                DBG("Receive : expecting %d fds", nb_fd);
                for (i = 0; i < nb_fd; i++) {
                        switch (cmd_type) {
-                               case LTTCOMM_ADD_STREAM:
-                                       DBG("add_fd %s (%d)", buf[i].path_name, ((int *)CMSG_DATA(cmsg))[i]);
-                                       ret = add_fd(&buf[i], ((int *)CMSG_DATA(cmsg))[i]);
-                                       if (ret < 0) {
-                                               send_error(KCONSUMERD_OUTFD_ERROR);
-                                               goto end;
-                                       }
-                                       break;
-                               case LTTCOMM_UPDATE_STREAM:
-                                       change_fd_state(buf[i].fd, buf[i].state);
-                                       break;
-                               default:
-                                       break;
+                       case ADD_STREAM:
+                               DBG("add_fd %s (%d)", buf[i].path_name, ((int *)CMSG_DATA(cmsg))[i]);
+                               ret = add_fd(&buf[i], ((int *)CMSG_DATA(cmsg))[i]);
+                               if (ret < 0) {
+                                       send_error(KCONSUMERD_OUTFD_ERROR);
+                                       goto end;
+                               }
+                               break;
+                       case UPDATE_STREAM:
+                               change_fd_state(buf[i].fd, buf[i].state);
+                               break;
+                       default:
+                               break;
                        }
                }
                /* flag to tell the polling thread to update its fd array */
@@ -486,6 +489,7 @@ static int consumerd_recv_fd(int sfd, int size,
        }
 
 end:
+       DBG("consumerd_recv_fd thread exiting");
        if (buf != NULL) {
                free(buf);
                buf = NULL;
@@ -509,43 +513,50 @@ static void *thread_receive_fds(void *data)
        client_socket = lttcomm_create_unix_sock(command_sock_path);
        if (client_socket < 0) {
                ERR("Cannot create command socket");
-               goto error;
+               goto end;
        }
 
        ret = lttcomm_listen_unix_sock(client_socket);
        if (ret < 0) {
-               goto error;
+               goto end;
        }
 
        DBG("Sending ready command to ltt-sessiond");
        ret = send_error(KCONSUMERD_COMMAND_SOCK_READY);
        if (ret < 0) {
                ERR("Error sending ready command to ltt-sessiond");
-               goto error;
+               goto end;
        }
 
        /* Blocking call, waiting for transmission */
        sock = lttcomm_accept_unix_sock(client_socket);
        if (sock <= 0) {
                WARN("On accept");
-               goto error;
+               goto end;
        }
        while (1) {
                /* 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) {
-                       ERR("Receiving the lttcomm_kconsumerd_header, exiting");
-                       goto error;
+                       ERR("Communication interrupted on command socket");
+                       goto end;
+               }
+               if (tmp.cmd_type == STOP) {
+                       DBG("Received STOP command");
+                       quit = 1;
+                       goto end;
                }
+               /* we received a command to add or update fds */
                ret = consumerd_recv_fd(sock, tmp.payload_size, tmp.cmd_type);
                if (ret <= 0) {
                        ERR("Receiving the FD, exiting");
-                       goto error;
+                       goto end;
                }
        }
 
-error:
+end:
+       DBG("thread_receive_fds exiting");
        return NULL;
 }
 
@@ -575,8 +586,6 @@ static int update_poll_array(struct pollfd **pollfd,
                        (*pollfd)[i].events = POLLIN | POLLPRI;
                        local_kconsumerd_fd[i] = iter;
                        i++;
-               } else if (iter->state == DELETE_FD) {
-                       del_fd(iter);
                }
        }
        /*
@@ -625,7 +634,7 @@ static void *thread_poll_fds(void *data)
                 * the ltt_fd_list has been updated, we need to update our
                 * local array as well
                 */
-               if (update_fd_array) {
+               if (update_fd_array == 1) {
                        if (pollfd != NULL) {
                                free(pollfd);
                                pollfd = NULL;
@@ -679,56 +688,61 @@ static void *thread_poll_fds(void *data)
                /* Take care of high priority channels first. */
                for (i = 0; i < nb_fd; i++) {
                        switch(pollfd[i].revents) {
-                               case POLLERR:
-                                       ERR("Error returned in polling fd %d.", pollfd[i].fd);
-                                       num_hup++;
-                                       send_error(KCONSUMERD_POLL_ERROR);
-                                       break;
-                               case POLLHUP:
-                                       ERR("Polling fd %d tells it has hung up.", pollfd[i].fd);
-                                       num_hup++;
-                                       break;
-                               case POLLNVAL:
-                                       ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
-                                       send_error(KCONSUMERD_POLL_NVAL);
-                                       num_hup++;
-                                       break;
-                               case POLLPRI:
-                                       DBG("Urgent read on fd %d", pollfd[i].fd);
-                                       high_prio = 1;
-                                       ret = read_subbuffer(local_kconsumerd_fd[i]);
-                                       /* it's ok to have an unavailable sub-buffer (FIXME : is it ?) */
-                                       if (ret == EAGAIN) {
-                                               ret = 0;
-                                       }
-                                       break;
+                       case POLLERR:
+                               ERR("Error returned in polling fd %d.", pollfd[i].fd);
+                               del_fd(local_kconsumerd_fd[i]);
+                               update_fd_array = 1;
+                               num_hup++;
+                               break;
+                       case POLLHUP:
+                               ERR("Polling fd %d tells it has hung up.", pollfd[i].fd);
+                               del_fd(local_kconsumerd_fd[i]);
+                               update_fd_array = 1;
+                               num_hup++;
+                               break;
+                       case POLLNVAL:
+                               ERR("Polling fd %d tells fd is not open.", pollfd[i].fd);
+                               del_fd(local_kconsumerd_fd[i]);
+                               update_fd_array = 1;
+                               num_hup++;
+                               break;
+                       case POLLPRI:
+                               DBG("Urgent read on fd %d", pollfd[i].fd);
+                               high_prio = 1;
+                               ret = read_subbuffer(local_kconsumerd_fd[i]);
+                               /* it's ok to have an unavailable sub-buffer (FIXME : is it ?) */
+                               if (ret == EAGAIN) {
+                                       ret = 0;
+                               }
+                               break;
                        }
                }
 
                /* If every buffer FD has hung up, we end the read loop here */
                if (nb_fd > 0 && num_hup == nb_fd) {
                        DBG("every buffer FD has hung up\n");
-                       send_error(KCONSUMERD_POLL_HUP);
-                       goto end;
+                       if (quit == 1) {
+                               goto end;
+                       }
+                       continue;
                }
 
                /* Take care of low priority channels. */
-               if (!high_prio) {
+               if (high_prio == 0) {
                        for (i = 0; i < nb_fd; i++) {
-                               switch(pollfd[i].revents) {
-                                       case POLLIN:
-                                               DBG("Normal read on fd %d", pollfd[i].fd);
-                                               ret = read_subbuffer(local_kconsumerd_fd[i]);
-                                               /* it's ok to have an unavailable subbuffer (FIXME : is it ?) */
-                                               if (ret == EAGAIN) {
-                                                       ret = 0;
-                                               }
-                                               break;
+                               if (pollfd[i].revents == POLLIN) {
+                                       DBG("Normal read on fd %d", pollfd[i].fd);
+                                       ret = read_subbuffer(local_kconsumerd_fd[i]);
+                                       /* it's ok to have an unavailable subbuffer (FIXME : is it ?) */
+                                       if (ret == EAGAIN) {
+                                               ret = 0;
+                                       }
                                }
                        }
                }
        }
 end:
+       DBG("polling thread exiting");
        if (pollfd != NULL) {
                free(pollfd);
                pollfd = NULL;
@@ -789,36 +803,36 @@ static void parse_args(int argc, char **argv)
                }
 
                switch (c) {
-                       case 0:
-                               fprintf(stderr, "option %s", long_options[option_index].name);
-                               if (optarg) {
-                                       fprintf(stderr, " with arg %s\n", optarg);
-                               }
-                               break;
-                       case 'c':
-                               snprintf(command_sock_path, PATH_MAX, "%s", optarg);
-                               break;
-                       case 'e':
-                               snprintf(error_sock_path, PATH_MAX, "%s", optarg);
-                               break;
-                       case 'd':
-                               opt_daemon = 1;
-                               break;
-                       case 'h':
-                               usage();
-                               exit(EXIT_FAILURE);
-                       case 'q':
-                               opt_quiet = 1;
-                               break;
-                       case 'v':
-                               opt_verbose = 1;
-                               break;
-                       case 'V':
-                               fprintf(stdout, "%s\n", VERSION);
-                               exit(EXIT_SUCCESS);
-                       default:
-                               usage();
-                               exit(EXIT_FAILURE);
+               case 0:
+                       fprintf(stderr, "option %s", long_options[option_index].name);
+                       if (optarg) {
+                               fprintf(stderr, " with arg %s\n", optarg);
+                       }
+                       break;
+               case 'c':
+                       snprintf(command_sock_path, PATH_MAX, "%s", optarg);
+                       break;
+               case 'e':
+                       snprintf(error_sock_path, PATH_MAX, "%s", optarg);
+                       break;
+               case 'd':
+                       opt_daemon = 1;
+                       break;
+               case 'h':
+                       usage();
+                       exit(EXIT_FAILURE);
+               case 'q':
+                       opt_quiet = 1;
+                       break;
+               case 'v':
+                       opt_verbose = 1;
+                       break;
+               case 'V':
+                       fprintf(stdout, "%s\n", VERSION);
+                       exit(EXIT_SUCCESS);
+               default:
+                       usage();
+                       exit(EXIT_FAILURE);
                }
        }
 }
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