Fix: add missing rcu read side lock

[lttng-tools.git] / src / bin / lttng-sessiond / main.c

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index 237a2cf8d75a3f3ee8dc1a68c7c63dfccc1526b2..339b20d3ee433be2d17f33d3462b104ab6266448 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -72,6 +72,7 @@ const char default_global_apps_pipe[] = DEFAULT_GLOBAL_APPS_PIPE;
 
 const char *progname;
 const char *opt_tracing_group;
+static const char *opt_pidfile;
 static int opt_sig_parent;
 static int opt_verbose_consumer;
 static int opt_daemon;
@@ -404,6 +405,17 @@ static void cleanup(void)
        /* First thing first, stop all threads */
        utils_close_pipe(thread_quit_pipe);
 
+       /*
+        * If opt_pidfile is undefined, the default file will be wiped when
+        * removing the rundir.
+        */
+       if (opt_pidfile) {
+               ret = remove(opt_pidfile);
+               if (ret < 0) {
+                       PERROR("remove pidfile %s", opt_pidfile);
+               }
+       }
+
        DBG("Removing %s directory", rundir);
        ret = asprintf(&cmd, "rm -rf %s", rundir);
        if (ret < 0) {
@@ -626,7 +638,7 @@ static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
                                        struct lttng_ht_iter iter;
                                        struct consumer_socket *socket;
 
-
+                                       rcu_read_lock();
                                        cds_lfht_for_each_entry(ksess->consumer->socks->ht,
                                                        &iter.iter, socket, node.node) {
                                                /* Code flow error */
@@ -637,9 +649,11 @@ static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
                                                                channel, ksess);
                                                pthread_mutex_unlock(socket->lock);
                                                if (ret < 0) {
+                                                       rcu_read_unlock();
                                                        goto error;
                                                }
                                        }
+                                       rcu_read_unlock();
                                }
                                goto error;
                        }
@@ -3406,6 +3420,7 @@ static void usage(void)
        fprintf(stderr, "  -S, --sig-parent                   Send SIGCHLD to parent pid to notify readiness.\n");
        fprintf(stderr, "  -q, --quiet                        No output at all.\n");
        fprintf(stderr, "  -v, --verbose                      Verbose mode. Activate DBG() macro.\n");
+       fprintf(stderr, "  -p, --pidfile FILE                 Write a pid to FILE name overriding the default value.\n");
        fprintf(stderr, "      --verbose-consumer             Verbose mode for consumer. Activate DBG() macro.\n");
        fprintf(stderr, "      --no-kernel                    Disable kernel tracer\n");
 }
@@ -3439,12 +3454,13 @@ static int parse_args(int argc, char **argv)
                { "verbose", 0, 0, 'v' },
                { "verbose-consumer", 0, 0, 'Z' },
                { "no-kernel", 0, 0, 'N' },
+               { "pidfile", 1, 0, 'p' },
                { NULL, 0, 0, 0 }
        };
 
        while (1) {
                int option_index = 0;
-               c = getopt_long(argc, argv, "dhqvVSN" "a:c:g:s:C:E:D:F:Z:u:t",
+               c = getopt_long(argc, argv, "dhqvVSN" "a:c:g:s:C:E:D:F:Z:u:t:p:",
                                long_options, &option_index);
                if (c == -1) {
                        break;
@@ -3521,6 +3537,9 @@ static int parse_args(int argc, char **argv)
                case 'T':
                        consumerd64_libdir = optarg;
                        break;
+               case 'p':
+                       opt_pidfile = optarg;
+                       break;
                default:
                        /* Unknown option or other error.
                         * Error is printed by getopt, just return */
@@ -3847,6 +3866,38 @@ static void set_ulimit(void)
        }
 }
 
+/*
+ * Write pidfile using the rundir and opt_pidfile.
+ */
+static void write_pidfile(void)
+{
+       int ret;
+       char pidfile_path[PATH_MAX];
+
+       assert(rundir);
+
+       if (opt_pidfile) {
+               strncpy(pidfile_path, opt_pidfile, sizeof(pidfile_path));
+       } else {
+               /* Build pidfile path from rundir and opt_pidfile. */
+               ret = snprintf(pidfile_path, sizeof(pidfile_path), "%s/"
+                               DEFAULT_LTTNG_SESSIOND_PIDFILE, rundir);
+               if (ret < 0) {
+                       PERROR("snprintf pidfile path");
+                       goto error;
+               }
+       }
+
+       /*
+        * Create pid file in rundir. Return value is of no importance. The
+        * execution will continue even though we are not able to write the file.
+        */
+       (void) utils_create_pid_file(getpid(), pidfile_path);
+
+error:
+       return;
+}
+
 /*
  * main
  */
@@ -4144,6 +4195,8 @@ int main(int argc, char **argv)
                app_socket_timeout = DEFAULT_APP_SOCKET_RW_TIMEOUT;
        }
 
+       write_pidfile();
+
        /* Create thread to manage the client socket */
        ret = pthread_create(&health_thread, NULL,
                        thread_manage_health, (void *) NULL);