Replace daemonize function by std glibc daemon()

[lttng-tools.git] / ltt-sessiond / ltt-sessiond.c

diff --git a/ltt-sessiond/ltt-sessiond.c b/ltt-sessiond/ltt-sessiond.c
index d846c89e58293016b3ffa4abb4c15b96655d8991..050c67397345eb0fa97a04239342959364926d90 100644 (file)
--- a/ltt-sessiond/ltt-sessiond.c
+++ b/ltt-sessiond/ltt-sessiond.c
@@ -48,7 +48,6 @@ const char default_global_apps_pipe[] = DEFAULT_GLOBAL_APPS_PIPE;
 static int set_signal_handler(void);
 static int set_socket_perms(void);
 static void sighandler(int);
-static void daemonize(void);
 static void cleanup(void);
 static void copy_common_data(struct lttcomm_lttng_msg *llm, struct lttcomm_session_msg *lsm);
 static int check_existing_daemon(void);
@@ -69,8 +68,10 @@ static struct ltt_session *find_session(uuid_t);
 /* Variables */
 const char *progname;
 const char *opt_tracing_group;
+static int opt_sig_parent;
 static int opt_daemon;
 static int is_root;                    /* Set to 1 if the daemon is running as root */
+static pid_t ppid;
 
 static char apps_unix_sock_path[PATH_MAX];                     /* Global application Unix socket path */
 static char client_unix_sock_path[PATH_MAX];           /* Global client Unix socket path */
@@ -185,6 +186,13 @@ static void *thread_manage_clients(void *data)
                goto error;
        }
 
+       /* Notify parent pid that we are ready
+        * to accept command for client side.
+        */
+       if (opt_sig_parent) {
+               kill(ppid, SIGCHLD);
+       }
+
        while (1) {
                /* Blocking call, waiting for transmission */
                sock = lttcomm_accept_unix_sock(client_socket);
@@ -511,7 +519,8 @@ static void usage(void)
                        "\t-a, --apps-sock PATH\t\tSpecify path for apps unix socket.\n"
                        "\t-d, --daemonize\t\tStart as a daemon.\n"
                        "\t-g, --group NAME\t\tSpecify the tracing group name. (default: tracing)\n"
-                       "\t-V, --version\t\tShow version number.\n",
+                       "\t-V, --version\t\tShow version number.\n"
+                       "\t-S, --sig-parent\t\tSend SIGCHLD to parent pid to notify readiness.\n",
                        progname);
 }
 
@@ -526,6 +535,7 @@ static int parse_args(int argc, char **argv)
                { "client-sock", 1, 0, 'c' },
                { "apps-sock", 1, 0, 'a' },
                { "daemonize", 0, 0, 'd' },
+               { "sig-parent", 0, 0, 'S' },
                { "help", 0, 0, 'h' },
                { "group", 1, 0, 'g' },
                { "version", 0, 0, 'V' },
@@ -534,7 +544,7 @@ static int parse_args(int argc, char **argv)
 
        while (1) {
                int option_index = 0;
-               c = getopt_long(argc, argv, "dhV" "a:c:g:s:", long_options, &option_index);
+               c = getopt_long(argc, argv, "dhVS" "a:c:g:s:", long_options, &option_index);
                if (c == -1) {
                        break;
                }
@@ -564,6 +574,9 @@ static int parse_args(int argc, char **argv)
                case 'V':
                        fprintf(stdout, "%s\n", VERSION);
                        exit(EXIT_SUCCESS);
+               case 'S':
+                       opt_sig_parent = 1;
+                       break;
                default:
                        /* Unknown option or other error.
                         * Error is printed by getopt, just return */
@@ -688,48 +701,6 @@ end:
        return ret;
 }
 
-/*
- *     daemonize
- *
- *     Daemonize ltt-sessiond.
- */
-static void daemonize(void)
-{
-       pid_t pid, sid;
-       const char *home_dir = get_home_dir();
-
-       /* Fork off the parent process */
-       if ((pid = fork()) < 0) {
-               perror("fork");
-               exit(EXIT_FAILURE);
-       }
-
-       /* Parent can now exit */
-       if (pid > 0) {
-               exit(EXIT_SUCCESS);
-       }
-
-       /* Change the file mode mask */
-       umask(0);
-
-       /* Create a new SID for the child process */
-       if ((sid = setsid()) < 0) {
-               perror("setsid");
-               exit(EXIT_FAILURE);
-       }
-
-       /* Change the current working directory */
-       if ((chdir(home_dir)) < 0) {
-               perror("chdir");
-               exit(EXIT_FAILURE);
-       }
-
-       /* Close out the standard file descriptors */
-       close(STDIN_FILENO);
-       close(STDOUT_FILENO);
-       close(STDERR_FILENO);
-}
-
 /*
  *     set_signal_handler
  *
@@ -822,7 +793,11 @@ int main(int argc, char **argv)
 
        /* Daemonize */
        if (opt_daemon) {
-               daemonize();
+               ret = daemon(0, 0);
+               if (ret < 0) {
+                       perror("daemon");
+                       goto error;
+               }
        }
 
        /* Check if daemon is UID = 0 */
@@ -874,6 +849,11 @@ int main(int argc, char **argv)
                goto error;
        }
 
+       /* Get parent pid if -S, --sig-parent is specified. */
+       if (opt_sig_parent) {
+               ppid = getppid();
+       }
+
        while (1) {
                /* Create thread to manage the client socket */
                ret = pthread_create(&threads[0], NULL, thread_manage_clients, (void *) NULL);