static int opt_no_sessiond;
static char *opt_sessiond_path;
static pid_t sessiond_pid;
+static volatile int recv_child_signal;
enum {
OPT_SESSION_PATH,
static void usage(FILE *ofp)
{
fprintf(ofp, "LTTng Trace Control " VERSION"\n\n");
- fprintf(ofp, "usage: lttng [options] <command>\n");
+ fprintf(ofp, "usage: lttng [OPTIONS] <COMMAND>\n");
fprintf(ofp, "\n");
fprintf(ofp, "Options:\n");
fprintf(ofp, " -h, --help Show this help\n");
- fprintf(ofp, " -g, --group NAME Unix tracing group name. (default: tracing)\n");
- fprintf(ofp, " -v, --verbose Verbose mode\n");
+ fprintf(ofp, " --list-options Simple listing of lttng options\n");
+ fprintf(ofp, " --list-commands Simple listing of lttng commands\n");
+ fprintf(ofp, " -v, --verbose Increase verbosity\n");
fprintf(ofp, " -q, --quiet Quiet mode\n");
+ fprintf(ofp, " -g, --group NAME Unix tracing group name. (default: tracing)\n");
fprintf(ofp, " -n, --no-sessiond Don't spawn a session daemon\n");
fprintf(ofp, " --sessiond-path Session daemon full path\n");
- fprintf(ofp, " --list-options Simple listing of lttng options\n");
- fprintf(ofp, " --list-commands Simple listing of lttng commands\n");
fprintf(ofp, "\n");
fprintf(ofp, "Commands:\n");
- fprintf(ofp, " add-context Add context to event or/and channel\n");
+ fprintf(ofp, " add-context Add context to event and/or channel\n");
fprintf(ofp, " calibrate Quantify LTTng overhead\n");
fprintf(ofp, " create Create tracing session\n");
- fprintf(ofp, " destroy Teardown tracing session\n");
+ fprintf(ofp, " destroy Tear down tracing session\n");
fprintf(ofp, " enable-channel Enable tracing channel\n");
fprintf(ofp, " enable-event Enable tracing event\n");
fprintf(ofp, " disable-channel Disable tracing channel\n");
case SIGCHLD:
DBG("SIGCHLD caugth");
waitpid(sessiond_pid, &status, 0);
+ recv_child_signal = 1;
/* Indicate that the session daemon died */
sessiond_pid = 0;
ERR("Session daemon died (exit status %d)", WEXITSTATUS(status));
break;
case SIGUSR1:
/* Notify is done */
+ recv_child_signal = 1;
DBG("SIGUSR1 caugth");
break;
default:
pid_t pid;
MSG("Spawning a session daemon");
+ recv_child_signal = 0;
pid = fork();
if (pid == 0) {
/*
} else {
perror("execlp");
}
- kill(getppid(), SIGTERM); /* unpause parent */
+ kill(getppid(), SIGTERM); /* wake parent */
exit(EXIT_FAILURE);
} else if (pid > 0) {
sessiond_pid = pid;
- /* Wait for lttng-sessiond to start */
- pause();
+ /*
+ * Wait for lttng-sessiond to start. We need to use a flag to check if
+ * the signal has been sent to us, because the child can be scheduled
+ * before the parent, and thus send the signal before this check. In
+ * the signal handler, we set the recv_child_signal flag, so anytime we
+ * check it after the fork is fine. Note that sleep() is interrupted
+ * before the 1 second delay as soon as the signal is received, so it
+ * will not cause visible delay for the user.
+ */
+ while (!recv_child_signal) {
+ sleep(1);
+ }
+ /*
+ * The signal handler will nullify sessiond_pid on SIGCHLD
+ */
if (!sessiond_pid) {
exit(EXIT_FAILURE);
}
if (opt_sessiond_path != NULL) {
ret = access(opt_sessiond_path, F_OK | X_OK);
if (ret < 0) {
- ERR("No such file: %s", opt_sessiond_path);
+ ERR("No such file or access denied: %s", opt_sessiond_path);
goto end;
}
pathname = opt_sessiond_path;
} else {
/* Try LTTNG_SESSIOND_PATH env variable */
- pathname = getenv(LTTNG_SESSIOND_PATH_ENV);
+ pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
}
/* Let's rock and roll */
ret = spawn_sessiond(pathname);
free(alloc_pathname);
if (ret < 0) {
- ERR("Problem occurs when starting %s", pathname);
+ ERR("Problem occurred when starting %s", pathname);
goto end;
}
}
int i;
for (i = 0; i < argc; i++) {
- if ((strncmp(argv[i], "-h", 2) == 0) ||
- strncmp(argv[i], "--h", 3) == 0 ||
- strncmp(argv[i], "--list-options", 14)) {
+ if ((strncmp(argv[i], "-h", sizeof("-h")) == 0) ||
+ strncmp(argv[i], "--h", sizeof("--h")) == 0 ||
+ strncmp(argv[i], "--list-options", sizeof("--list-options")) == 0 ||
+ strncmp(argv[i], "--list-commands", sizeof("--list-commands")) == 0) {
return 1;
}
}
}
/*
- * parse_args
+ * Parse command line arguments.
*
- * Parse command line arguments.
- * Return 0 if OK, else -1
+ * Return 0 if OK, else -1
*/
static int parse_args(int argc, char **argv)
{
while ((opt = getopt_long(argc, argv, "+hnvqg:", long_options, NULL)) != -1) {
switch (opt) {
case 'h':
- usage(stderr);
- goto error;
+ usage(stdout);
+ goto end;
case 'v':
opt_verbose += 1;
break;
case OPT_DUMP_OPTIONS:
list_options(stdout);
ret = 0;
- goto error;
+ goto end;
case OPT_DUMP_COMMANDS:
list_commands(stdout);
ret = 0;
- goto error;
+ goto end;
default:
usage(stderr);
goto error;
goto error;
}
+end:
return 0;
error:
projects / lttng-tools.git / blobdiff