16582b0363b86fa1405d4afd6d1751f3c36b9499
[lttng-tools.git] / src / bin / lttng / lttng.c
1 /*
2 * Copyright (c) 2011 David Goulet <david.goulet@polymtl.ca>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * as published by the Free Software Foundation; only version 2
7 * of the License.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _GNU_SOURCE
20 #include <getopt.h>
21 #include <signal.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/types.h>
26 #include <sys/wait.h>
27 #include <unistd.h>
28 #include <config.h>
29 #include <ctype.h>
30
31 #include <lttng/lttng.h>
32 #include <common/error.h>
33
34 #include "command.h"
35
36 /* Variables */
37 static char *progname;
38
39 int opt_quiet;
40 int opt_verbose;
41 static int opt_no_sessiond;
42 static char *opt_sessiond_path;
43 static pid_t sessiond_pid;
44 static volatile int recv_child_signal;
45
46 enum {
47 OPT_SESSION_PATH,
48 OPT_DUMP_OPTIONS,
49 OPT_DUMP_COMMANDS,
50 };
51
52 /* Getopt options. No first level command. */
53 static struct option long_options[] = {
54 {"help", 0, NULL, 'h'},
55 {"group", 1, NULL, 'g'},
56 {"verbose", 0, NULL, 'v'},
57 {"quiet", 0, NULL, 'q'},
58 {"no-sessiond", 0, NULL, 'n'},
59 {"sessiond-path", 1, NULL, OPT_SESSION_PATH},
60 {"list-options", 0, NULL, OPT_DUMP_OPTIONS},
61 {"list-commands", 0, NULL, OPT_DUMP_COMMANDS},
62 {NULL, 0, NULL, 0}
63 };
64
65 /* First level command */
66 static struct cmd_struct commands[] = {
67 { "list", cmd_list},
68 { "create", cmd_create},
69 { "destroy", cmd_destroy},
70 { "start", cmd_start},
71 { "stop", cmd_stop},
72 { "enable-event", cmd_enable_events},
73 { "disable-event", cmd_disable_events},
74 { "enable-channel", cmd_enable_channels},
75 { "disable-channel", cmd_disable_channels},
76 { "add-context", cmd_add_context},
77 { "set-session", cmd_set_session},
78 { "version", cmd_version},
79 { "calibrate", cmd_calibrate},
80 { "view", cmd_view},
81 { NULL, NULL} /* Array closure */
82 };
83
84 static void usage(FILE *ofp)
85 {
86 fprintf(ofp, "LTTng Trace Control " VERSION"\n\n");
87 fprintf(ofp, "usage: lttng [OPTIONS] <COMMAND>\n");
88 fprintf(ofp, "\n");
89 fprintf(ofp, "Options:\n");
90 fprintf(ofp, " -h, --help Show this help\n");
91 fprintf(ofp, " --list-options Simple listing of lttng options\n");
92 fprintf(ofp, " --list-commands Simple listing of lttng commands\n");
93 fprintf(ofp, " -v, --verbose Increase verbosity\n");
94 fprintf(ofp, " -q, --quiet Quiet mode\n");
95 fprintf(ofp, " -g, --group NAME Unix tracing group name. (default: tracing)\n");
96 fprintf(ofp, " -n, --no-sessiond Don't spawn a session daemon\n");
97 fprintf(ofp, " --sessiond-path PATH Session daemon full path\n");
98 fprintf(ofp, "\n");
99 fprintf(ofp, "Commands:\n");
100 fprintf(ofp, " add-context Add context to event and/or channel\n");
101 fprintf(ofp, " calibrate Quantify LTTng overhead\n");
102 fprintf(ofp, " create Create tracing session\n");
103 fprintf(ofp, " destroy Tear down tracing session\n");
104 fprintf(ofp, " enable-channel Enable tracing channel\n");
105 fprintf(ofp, " enable-event Enable tracing event\n");
106 fprintf(ofp, " disable-channel Disable tracing channel\n");
107 fprintf(ofp, " disable-event Disable tracing event\n");
108 fprintf(ofp, " list List possible tracing options\n");
109 fprintf(ofp, " set-session Set current session name\n");
110 fprintf(ofp, " start Start tracing\n");
111 fprintf(ofp, " stop Stop tracing\n");
112 fprintf(ofp, " version Show version information\n");
113 fprintf(ofp, " view Start trace viewer\n");
114 fprintf(ofp, "\n");
115 fprintf(ofp, "Each command also has its own -h, --help option.\n");
116 fprintf(ofp, "\n");
117 fprintf(ofp, "Please see the lttng(1) man page for full documentation.\n");
118 fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n");
119 }
120
121 /*
122 * list_options
123 *
124 * List options line by line. This is mostly for bash auto completion and to
125 * avoid difficult parsing.
126 */
127 static void list_options(FILE *ofp)
128 {
129 int i = 0;
130 struct option *option = NULL;
131
132 option = &long_options[i];
133 while (option->name != NULL) {
134 fprintf(ofp, "--%s\n", option->name);
135
136 if (isprint(option->val)) {
137 fprintf(ofp, "-%c\n", option->val);
138 }
139
140 i++;
141 option = &long_options[i];
142 }
143 }
144
145 /*
146 * list_commands
147 *
148 * List commands line by line. This is mostly for bash auto completion and to
149 * avoid difficult parsing.
150 */
151 static void list_commands(FILE *ofp)
152 {
153 int i = 0;
154 struct cmd_struct *cmd = NULL;
155
156 cmd = &commands[i];
157 while (cmd->name != NULL) {
158 fprintf(ofp, "%s\n", cmd->name);
159 i++;
160 cmd = &commands[i];
161 }
162 }
163
164 /*
165 * clean_exit
166 */
167 static void clean_exit(int code)
168 {
169 DBG("Clean exit");
170 exit(code);
171 }
172
173 /*
174 * sighandler
175 *
176 * Signal handler for the daemon
177 */
178 static void sighandler(int sig)
179 {
180 int status;
181
182 switch (sig) {
183 case SIGTERM:
184 DBG("SIGTERM caught");
185 clean_exit(EXIT_FAILURE);
186 break;
187 case SIGCHLD:
188 DBG("SIGCHLD caught");
189 waitpid(sessiond_pid, &status, 0);
190 recv_child_signal = 1;
191 /* Indicate that the session daemon died */
192 sessiond_pid = 0;
193 ERR("Session daemon died (exit status %d)", WEXITSTATUS(status));
194 break;
195 case SIGUSR1:
196 /* Notify is done */
197 recv_child_signal = 1;
198 DBG("SIGUSR1 caught");
199 break;
200 default:
201 DBG("Unknown signal %d caught", sig);
202 break;
203 }
204
205 return;
206 }
207
208 /*
209 * set_signal_handler
210 *
211 * Setup signal handler for SIGCHLD and SIGTERM.
212 */
213 static int set_signal_handler(void)
214 {
215 int ret = 0;
216 struct sigaction sa;
217 sigset_t sigset;
218
219 if ((ret = sigemptyset(&sigset)) < 0) {
220 perror("sigemptyset");
221 goto end;
222 }
223
224 sa.sa_handler = sighandler;
225 sa.sa_mask = sigset;
226 sa.sa_flags = 0;
227 if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
228 perror("sigaction");
229 goto end;
230 }
231
232 if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
233 perror("sigaction");
234 goto end;
235 }
236
237 if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
238 perror("sigaction");
239 goto end;
240 }
241
242 end:
243 return ret;
244 }
245
246 /*
247 * handle_command
248 *
249 * Handle the full argv list of a first level command. Will find the command
250 * in the global commands array and call the function callback associated.
251 *
252 * If command not found, return -1
253 * else, return function command error code.
254 */
255 static int handle_command(int argc, char **argv)
256 {
257 int i = 0, ret;
258 struct cmd_struct *cmd;
259
260 if (*argv == NULL) {
261 ret = CMD_SUCCESS;
262 goto end;
263 }
264
265 cmd = &commands[i];
266 while (cmd->func != NULL) {
267 /* Find command */
268 if (strcmp(argv[0], cmd->name) == 0) {
269 ret = cmd->func(argc, (const char**) argv);
270 goto end;
271 }
272 i++;
273 cmd = &commands[i];
274 }
275
276 /* Command not found */
277 ret = -1;
278
279 end:
280 return ret;
281 }
282
283 /*
284 * spawn_sessiond
285 *
286 * Spawn a session daemon by forking and execv.
287 */
288 static int spawn_sessiond(char *pathname)
289 {
290 int ret = 0;
291 pid_t pid;
292
293 MSG("Spawning a session daemon");
294 recv_child_signal = 0;
295 pid = fork();
296 if (pid == 0) {
297 /*
298 * Spawn session daemon and tell
299 * it to signal us when ready.
300 */
301 execlp(pathname, "lttng-sessiond", "--sig-parent", "--quiet", NULL);
302 /* execlp only returns if error happened */
303 if (errno == ENOENT) {
304 ERR("No session daemon found. Use --sessiond-path.");
305 } else {
306 perror("execlp");
307 }
308 kill(getppid(), SIGTERM); /* wake parent */
309 exit(EXIT_FAILURE);
310 } else if (pid > 0) {
311 sessiond_pid = pid;
312 /*
313 * Wait for lttng-sessiond to start. We need to use a flag to check if
314 * the signal has been sent to us, because the child can be scheduled
315 * before the parent, and thus send the signal before this check. In
316 * the signal handler, we set the recv_child_signal flag, so anytime we
317 * check it after the fork is fine. Note that sleep() is interrupted
318 * before the 1 second delay as soon as the signal is received, so it
319 * will not cause visible delay for the user.
320 */
321 while (!recv_child_signal) {
322 sleep(1);
323 }
324 /*
325 * The signal handler will nullify sessiond_pid on SIGCHLD
326 */
327 if (!sessiond_pid) {
328 exit(EXIT_FAILURE);
329 }
330 goto end;
331 } else {
332 perror("fork");
333 ret = -1;
334 goto end;
335 }
336
337 end:
338 return ret;
339 }
340
341 /*
342 * check_sessiond
343 *
344 * Check if the session daemon is available using
345 * the liblttngctl API for the check. If not, try to
346 * spawn a daemon.
347 */
348 static int check_sessiond(void)
349 {
350 int ret;
351 char *pathname = NULL, *alloc_pathname = NULL;
352
353 ret = lttng_session_daemon_alive();
354 if (ret == 0) { /* not alive */
355 /* Try command line option path */
356 if (opt_sessiond_path != NULL) {
357 ret = access(opt_sessiond_path, F_OK | X_OK);
358 if (ret < 0) {
359 ERR("No such file or access denied: %s", opt_sessiond_path);
360 goto end;
361 }
362 pathname = opt_sessiond_path;
363 } else {
364 /* Try LTTNG_SESSIOND_PATH env variable */
365 pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
366 }
367
368 /* Let's rock and roll */
369 if (pathname == NULL) {
370 ret = asprintf(&alloc_pathname, INSTALL_BIN_PATH "/lttng-sessiond");
371 if (ret < 0) {
372 perror("asprintf spawn sessiond");
373 goto end;
374 }
375 pathname = alloc_pathname;
376 }
377
378 ret = spawn_sessiond(pathname);
379 free(alloc_pathname);
380 if (ret < 0) {
381 ERR("Problem occurred when starting %s", pathname);
382 goto end;
383 }
384 }
385
386 end:
387 return ret;
388 }
389
390 /*
391 * Check args for specific options that *must* not trigger a session daemon
392 * execution.
393 *
394 * Return 1 if match else 0.
395 */
396 static int check_args_no_sessiond(int argc, char **argv)
397 {
398 int i;
399
400 for (i = 0; i < argc; i++) {
401 if ((strncmp(argv[i], "-h", sizeof("-h")) == 0) ||
402 strncmp(argv[i], "--h", sizeof("--h")) == 0 ||
403 strncmp(argv[i], "--list-options", sizeof("--list-options")) == 0 ||
404 strncmp(argv[i], "--list-commands", sizeof("--list-commands")) == 0 ||
405 strncmp(argv[i], "version", sizeof("version")) == 0 ||
406 strncmp(argv[i], "view", sizeof("view")) == 0) {
407 return 1;
408 }
409 }
410
411 return 0;
412 }
413
414 /*
415 * Parse command line arguments.
416 *
417 * Return 0 if OK, else -1
418 */
419 static int parse_args(int argc, char **argv)
420 {
421 int opt, ret;
422
423 if (argc < 2) {
424 usage(stderr);
425 clean_exit(EXIT_FAILURE);
426 }
427
428 while ((opt = getopt_long(argc, argv, "+hnvqg:", long_options, NULL)) != -1) {
429 switch (opt) {
430 case 'h':
431 usage(stdout);
432 ret = 0;
433 goto end;
434 case 'v':
435 opt_verbose += 1;
436 break;
437 case 'q':
438 opt_quiet = 1;
439 break;
440 case 'g':
441 lttng_set_tracing_group(optarg);
442 break;
443 case 'n':
444 opt_no_sessiond = 1;
445 break;
446 case OPT_SESSION_PATH:
447 opt_sessiond_path = strdup(optarg);
448 break;
449 case OPT_DUMP_OPTIONS:
450 list_options(stdout);
451 ret = 0;
452 goto end;
453 case OPT_DUMP_COMMANDS:
454 list_commands(stdout);
455 ret = 0;
456 goto end;
457 default:
458 usage(stderr);
459 ret = 1;
460 goto error;
461 }
462 }
463
464 /* If both options are specified, quiet wins */
465 if (opt_verbose && opt_quiet) {
466 opt_verbose = 0;
467 }
468
469 /* Spawn session daemon if needed */
470 if (opt_no_sessiond == 0 && check_args_no_sessiond(argc, argv) == 0 &&
471 (check_sessiond() < 0)) {
472 ret = 1;
473 goto error;
474 }
475
476 /* No leftovers, print usage and quit */
477 if ((argc - optind) == 0) {
478 usage(stderr);
479 ret = 1;
480 goto error;
481 }
482
483 /*
484 * Handle leftovers which is a first level command with the trailing
485 * options.
486 */
487 ret = handle_command(argc - optind, argv + optind);
488 switch (ret) {
489 case CMD_WARNING:
490 WARN("Some command(s) went wrong");
491 break;
492 case CMD_ERROR:
493 ERR("Command error");
494 break;
495 case CMD_UNDEFINED:
496 ERR("Undefined command");
497 break;
498 case CMD_FATAL:
499 ERR("Fatal error");
500 break;
501 case -1:
502 usage(stderr);
503 ret = 1;
504 break;
505 case 0:
506 break;
507 default:
508 ERR("%s", lttng_strerror(ret));
509 break;
510 }
511
512 end:
513 error:
514 return ret;
515 }
516
517
518 /*
519 * main
520 */
521 int main(int argc, char *argv[])
522 {
523 int ret;
524
525 progname = argv[0] ? argv[0] : "lttng";
526
527 /* For Mathieu Desnoyers a.k.a. Dr. Tracing */
528 if (strncmp(progname, "drtrace", 7) == 0 ||
529 strncmp("compudj", getenv("USER"), 7) == 0) {
530 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n", 27,1,33,27,0);
531 }
532
533 ret = set_signal_handler();
534 if (ret < 0) {
535 clean_exit(ret);
536 }
537
538 ret = parse_args(argc, argv);
539 if (ret != 0) {
540 clean_exit(ret);
541 }
542
543 return 0;
544 }
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