Fix: relayd: add LPOLLERR to events

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

diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index 506bbc6fb87249fe933cab9be2dfadb7f0a11d1c..62e149ed2cbdaf574968cbbe93659c48c8907db3 100644 (file)
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -45,6 +45,7 @@
 #include <common/compat/poll.h>
 #include <common/compat/socket.h>
 #include <common/defaults.h>
+#include <common/daemonize.h>
 #include <common/futex.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 #include <common/sessiond-comm/inet.h>
@@ -63,7 +64,17 @@
 
 /* command line options */
 char *opt_output_path;
-static int opt_daemon;
+static int opt_daemon, opt_background;
+
+/*
+ * We need to wait for listener and live listener threads, as well as
+ * health check thread, before being ready to signal readiness.
+ */
+#define NR_LTTNG_RELAY_READY   3
+static int lttng_relay_ready = NR_LTTNG_RELAY_READY;
+static int recv_child_signal;  /* Set to 1 when a SIGUSR1 signal is received. */
+static pid_t child_ppid;       /* Internal parent PID use with daemonize. */
+
 static struct lttng_uri *control_uri;
 static struct lttng_uri *data_uri;
 static struct lttng_uri *live_uri;
@@ -131,6 +142,7 @@ static struct option long_options[] = {
        { "data-port", 1, 0, 'D', },
        { "live-port", 1, 0, 'L', },
        { "daemonize", 0, 0, 'd', },
+       { "background", 0, 0, 'b', },
        { "group", 1, 0, 'g', },
        { "help", 0, 0, 'h', },
        { "output", 1, 0, 'o', },
@@ -150,6 +162,7 @@ void usage(void)
        fprintf(stderr, "Usage: %s OPTIONS\n\nOptions:\n", progname);
        fprintf(stderr, "  -h, --help                Display this usage.\n");
        fprintf(stderr, "  -d, --daemonize           Start as a daemon.\n");
+       fprintf(stderr, "  -b, --background          Start as a daemon, keeping console open.\n");
        fprintf(stderr, "  -C, --control-port URL    Control port listening.\n");
        fprintf(stderr, "  -D, --data-port URL       Data port listening.\n");
        fprintf(stderr, "  -L, --live-port URL       Live view port listening.\n");
@@ -210,6 +223,9 @@ int set_option(int opt, const char *arg, const char *optname)
        case 'd':
                opt_daemon = 1;
                break;
+       case 'b':
+               opt_background = 1;
+               break;
        case 'g':
                tracing_group_name = strdup(arg);
                tracing_group_name_override = 1;
@@ -504,6 +520,9 @@ void sighandler(int sig)
                DBG("SIGTERM caught");
                stop_threads();
                break;
+       case SIGUSR1:
+               CMM_STORE_SHARED(recv_child_signal, 1);
+               break;
        default:
                break;
        }
@@ -543,11 +562,26 @@ int set_signal_handler(void)
                return ret;
        }
 
-       DBG("Signal handler set for SIGTERM, SIGPIPE and SIGINT");
+       if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
+               PERROR("sigaction");
+               return ret;
+       }
+
+       DBG("Signal handler set for SIGTERM, SIGUSR1, SIGPIPE and SIGINT");
 
        return ret;
 }
 
+void lttng_relay_notify_ready(void)
+{
+       /* Notify the parent of the fork() process that we are ready. */
+       if (opt_daemon || opt_background) {
+               if (uatomic_sub_return(&lttng_relay_ready, 1) == 0) {
+                       kill(child_ppid, SIGUSR1);
+               }
+       }
+}
+
 /*
  * Init thread quit pipe.
  *
@@ -582,7 +616,7 @@ int create_thread_poll_set(struct lttng_poll_event *events, int size)
        }
 
        /* Add quit pipe */
-       ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN);
+       ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
        if (ret < 0) {
                goto error;
        }
@@ -717,6 +751,8 @@ void *relay_thread_listener(void *data)
                goto error_poll_add;
        }
 
+       lttng_relay_notify_ready();
+
        while (1) {
                health_code_update();
 
@@ -2817,11 +2853,6 @@ int main(int argc, char **argv)
        void *status;
        struct relay_local_data *relay_ctx;
 
-       /* Create thread quit pipe */
-       if ((ret = init_thread_quit_pipe()) < 0) {
-               goto error;
-       }
-
        /* Parse arguments */
        progname = argv[0];
        if ((ret = set_options(argc, argv)) < 0) {
@@ -2847,12 +2878,28 @@ int main(int argc, char **argv)
        }
 
        /* Daemonize */
-       if (opt_daemon) {
-               ret = daemon(0, 0);
+       if (opt_daemon || opt_background) {
+               int i;
+
+               ret = lttng_daemonize(&child_ppid, &recv_child_signal,
+                       !opt_background);
                if (ret < 0) {
-                       PERROR("daemon");
                        goto exit;
                }
+
+               /*
+                * We are in the child. Make sure all other file
+                * descriptors are closed, in case we are called with
+                * more opened file descriptors than the standard ones.
+                */
+               for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
+                       (void) close(i);
+               }
+       }
+
+       /* Create thread quit pipe */
+       if ((ret = init_thread_quit_pipe()) < 0) {
+               goto error;
        }
 
        /* We need those values for the file/dir creation. */