X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng%2Flttng.c;h=f84ba63d7e8de48e4a9b6f44c79bbeffa72a7a89;hp=7058dd529d1ecd73e3a191f84e08b0883b54628e;hb=6d1fcf1c029c10dd79c3be0686b1fae567604406;hpb=8db8d1dc9f11aa7995b2f77bb938f2585005413c diff --git a/src/bin/lttng/lttng.c b/src/bin/lttng/lttng.c index 7058dd529..f84ba63d7 100644 --- a/src/bin/lttng/lttng.c +++ b/src/bin/lttng/lttng.c @@ -40,6 +40,7 @@ int opt_verbose; 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, @@ -81,23 +82,23 @@ static struct cmd_struct commands[] = { static void usage(FILE *ofp) { fprintf(ofp, "LTTng Trace Control " VERSION"\n\n"); - fprintf(ofp, "usage: lttng [options] \n"); + fprintf(ofp, "usage: lttng [OPTIONS] \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, " -q, --quiet Quiet mode\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, " -h, --help Show this help\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 PATH Session daemon full path\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"); @@ -108,6 +109,8 @@ static void usage(FILE *ofp) fprintf(ofp, " stop Stop tracing\n"); fprintf(ofp, " version Show version information\n"); fprintf(ofp, "\n"); + fprintf(ofp, "Each command also has its own -h, --help option.\n"); + fprintf(ofp, "\n"); fprintf(ofp, "Please see the lttng(1) man page for full documentation.\n"); fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n"); } @@ -175,22 +178,24 @@ static void sighandler(int sig) switch (sig) { case SIGTERM: - DBG("SIGTERM caugth"); + DBG("SIGTERM caught"); clean_exit(EXIT_FAILURE); break; case SIGCHLD: - DBG("SIGCHLD caugth"); + DBG("SIGCHLD caught"); 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 */ - DBG("SIGUSR1 caugth"); + recv_child_signal = 1; + DBG("SIGUSR1 caught"); break; default: - DBG("Unknown signal %d caugth", sig); + DBG("Unknown signal %d caught", sig); break; } @@ -259,20 +264,6 @@ static int handle_command(int argc, char **argv) /* Find command */ if (strcmp(argv[0], cmd->name) == 0) { ret = cmd->func(argc, (const char**) argv); - switch (ret) { - case CMD_ERROR: - ERR("Command error"); - break; - case CMD_NOT_IMPLEMENTED: - ERR("Options not implemented"); - break; - case CMD_UNDEFINED: - ERR("Undefined command"); - break; - case CMD_FATAL: - ERR("Fatal error"); - break; - } goto end; } i++; @@ -297,6 +288,7 @@ static int spawn_sessiond(char *pathname) pid_t pid; MSG("Spawning a session daemon"); + recv_child_signal = 0; pid = fork(); if (pid == 0) { /* @@ -310,12 +302,25 @@ static int spawn_sessiond(char *pathname) } 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); } @@ -348,13 +353,13 @@ static int check_sessiond(void) 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 */ @@ -370,7 +375,7 @@ static int check_sessiond(void) 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; } } @@ -380,15 +385,21 @@ end: } /* - * Check for the "help" option in the argv. If found, return 1 else return 0. + * Check args for specific options that *must* not trigger a session daemon + * execution. + * + * Return 1 if match else 0. */ -static int check_help_command(int argc, char **argv) +static int check_args_no_sessiond(int argc, char **argv) { int i; for (i = 0; i < argc; i++) { - if ((strncmp(argv[i], "-h", 2) == 0) || - strncmp(argv[i], "--h", 3) == 0) { + 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 || + strncmp(argv[i], "version", sizeof("version")) == 0) { return 1; } } @@ -397,10 +408,9 @@ static int check_help_command(int argc, char **argv) } /* - * 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) { @@ -414,8 +424,9 @@ 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); + ret = 0; + goto end; case 'v': opt_verbose += 1; break; @@ -434,13 +445,14 @@ static int parse_args(int argc, char **argv) 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); + ret = 1; goto error; } } @@ -451,14 +463,16 @@ static int parse_args(int argc, char **argv) } /* Spawn session daemon if needed */ - if (opt_no_sessiond == 0 && check_help_command(argc, argv) == 0 && + if (opt_no_sessiond == 0 && check_args_no_sessiond(argc, argv) == 0 && (check_sessiond() < 0)) { + ret = 1; goto error; } /* No leftovers, print usage and quit */ if ((argc - optind) == 0) { usage(stderr); + ret = 1; goto error; } @@ -467,19 +481,33 @@ static int parse_args(int argc, char **argv) * options. */ ret = handle_command(argc - optind, argv + optind); - if (ret < 0) { - if (ret == -1) { - usage(stderr); - } else { - ERR("%s", lttng_strerror(ret)); - } - goto error; + switch (ret) { + case CMD_WARNING: + WARN("Some command(s) went wrong"); + break; + case CMD_ERROR: + ERR("Command error"); + break; + case CMD_UNDEFINED: + ERR("Undefined command"); + break; + case CMD_FATAL: + ERR("Fatal error"); + break; + case -1: + usage(stderr); + ret = 1; + break; + case 0: + break; + default: + ERR("%s", lttng_strerror(ret)); + break; } - return 0; - +end: error: - return -1; + return ret; } @@ -492,9 +520,10 @@ int main(int argc, char *argv[]) progname = argv[0] ? argv[0] : "lttng"; - /* For Mathieu Desnoyers aka Dr Tracing */ - if (strncmp(progname, "drtrace", 7) == 0) { - MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0); + /* For Mathieu Desnoyers a.k.a. Dr. Tracing */ + if (strncmp(progname, "drtrace", 7) == 0 || + strncmp("compudj", getenv("USER"), 7) == 0) { + MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n", 27,1,33,27,0); } ret = set_signal_handler(); @@ -503,8 +532,8 @@ int main(int argc, char *argv[]) } ret = parse_args(argc, argv); - if (ret < 0) { - clean_exit(EXIT_FAILURE); + if (ret != 0) { + clean_exit(ret); } return 0;