Add support for shorten session uuid
[lttng-tools.git] / 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 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
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 <errno.h>
21 #include <fcntl.h>
22 #include <getopt.h>
23 #include <grp.h>
24 #include <limits.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <sys/stat.h>
29 #include <sys/types.h>
30 #include <sys/wait.h>
31 #include <unistd.h>
32
33 #include <lttng/lttng.h>
34
35 #include "lttng.h"
36 #include "lttngerr.h"
37
38 /* Variables */
39 static char *progname;
40 static char short_uuid[9];
41
42 /* Prototypes */
43 static int process_client_opt(void);
44 static int process_opt_list_apps(void);
45 static int process_opt_list_sessions(void);
46 static int process_opt_list_traces(void);
47 static int process_opt_create_session(void);
48 static int process_opt_session_uuid(void);
49 static void sighandler(int sig);
50 static void shorten_uuid(char *in, char *out);
51 static int set_signal_handler(void);
52 static int validate_options(void);
53 static char *get_cmdline_by_pid(pid_t pid);
54
55 /*
56 * start_client
57 *
58 * Process client request from the command line
59 * options. Every tracing action is done by the
60 * liblttngctl API.
61 */
62 static int process_client_opt(void)
63 {
64 int ret;
65 uuid_t uuid;
66
67 if (opt_list_apps) {
68 ret = process_opt_list_apps();
69 if (ret < 0) {
70 goto end;
71 }
72 }
73
74 if (opt_list_session) {
75 ret = process_opt_list_sessions();
76 if (ret < 0) {
77 goto end;
78 }
79 }
80
81 if (opt_list_traces) {
82 ret = process_opt_list_traces();
83 if (ret < 0) {
84 goto end;
85 }
86 }
87
88 if (opt_create_session != NULL) {
89 ret = process_opt_create_session();
90 if (ret < 0) {
91 goto end;
92 }
93 }
94
95 if (opt_destroy_session != NULL) {
96 uuid_parse(opt_destroy_session, uuid);
97 ret = lttng_destroy_session(&uuid);
98 if (ret < 0) {
99 goto end;
100 }
101 }
102
103 if (opt_session_uuid != NULL) {
104 DBG("Set session uuid to %s", short_uuid);
105 ret = process_opt_session_uuid();
106 if (ret < 0) {
107 ERR("Session UUID %s not found", opt_session_uuid);
108 goto error;
109 }
110 }
111
112 if (opt_trace_kernel) {
113 ERR("Not implemented yet");
114 goto end;
115 }
116
117 if (opt_trace_pid != 0) {
118 if (opt_create_trace) {
119 DBG("Create a userspace trace for pid %d", opt_trace_pid);
120 ret = lttng_ust_create_trace(opt_trace_pid);
121 if (ret < 0) {
122 goto end;
123 }
124 MSG("Trace created successfully!\nUse --start to start tracing.");
125 }
126
127 if (opt_start_trace) {
128 DBG("Start trace for pid %d", opt_trace_pid);
129 ret = lttng_ust_start_trace(opt_trace_pid);
130 if (ret < 0) {
131 goto end;
132 }
133 MSG("Trace started successfully!");
134 } else if (opt_stop_trace) {
135 DBG("Stop trace for pid %d", opt_trace_pid);
136 ret = lttng_ust_stop_trace(opt_trace_pid);
137 if (ret < 0) {
138 goto end;
139 }
140 MSG("Trace stopped successfully!");
141 }
142
143 }
144
145 return 0;
146
147 end:
148 ERR("%s", lttng_get_readable_code(ret));
149 return ret;
150
151 error:
152 return ret;
153 }
154
155 /*
156 * process_opt_session_uuid
157 *
158 * Set current session uuid to the current flow of
159 * command(s) using the already shorten uuid.
160 */
161 static int process_opt_session_uuid(void)
162 {
163 int ret, count, i;
164 struct lttng_session *sessions;
165
166 count = lttng_list_sessions(&sessions);
167 if (count < 0) {
168 ret = count;
169 goto error;
170 }
171
172 for (i = 0; i < count; i++) {
173 if (strncmp(sessions[i].uuid, short_uuid, 8) == 0) {
174 lttng_set_current_session_uuid(sessions[i].uuid);
175 break;
176 }
177 }
178
179 free(sessions);
180
181 return 0;
182
183 error:
184 return ret;
185 }
186
187 /*
188 * process_opt_list_traces
189 *
190 * Get list of all traces for a specific session uuid.
191 */
192 static int process_opt_list_traces(void)
193 {
194 int ret, i;
195 uuid_t uuid;
196 struct lttng_trace *traces;
197
198 uuid_parse(opt_session_uuid, uuid);
199 ret = lttng_list_traces(&uuid, &traces);
200 if (ret < 0) {
201 goto error;
202 }
203
204 MSG("Userspace traces:");
205 for (i = 0; i < ret; i++) {
206 if (traces[i].type == USERSPACE) {
207 MSG("\t%d) %s (pid: %d): %s",
208 i, traces[i].name, traces[i].pid,
209 get_cmdline_by_pid(traces[i].pid));
210 } else {
211 break;
212 }
213 }
214
215 MSG("Kernel traces:");
216 for (;i < ret; i++) {
217 if (traces[i].type == KERNEL) {
218 MSG("\t%d) %s", i, traces[i].name);
219 }
220 }
221
222 free(traces);
223
224 error:
225 return ret;
226 }
227
228 /*
229 * process_opt_create_session
230 *
231 * Create a new session using the name pass
232 * to the command line.
233 */
234 static int process_opt_create_session(void)
235 {
236 int ret;
237 uuid_t session_id;
238 char str_uuid[37];
239
240 ret = lttng_create_session(opt_create_session, &session_id);
241 if (ret < 0) {
242 goto error;
243 }
244
245 uuid_unparse(session_id, str_uuid);
246
247 MSG("Session created:");
248 MSG(" %s (%s)", opt_create_session, str_uuid);
249
250 error:
251 return ret;
252 }
253
254 /*
255 * extract_short_uuid
256 *
257 * Extract shorten uuid and copy it to out.
258 * Shorten uuid format : '<name>.<short_uuid>'
259 */
260 static int extract_short_uuid(char *in, char *out)
261 {
262 char *tok;
263
264 tok = strchr(in, '.');
265 if (strlen(tok+1) == 8) {
266 memcpy(out, tok+1, 8);
267 out[9] = '\0';
268 return 0;
269 }
270
271 return -1;
272 }
273
274 /*
275 * shorten_uuid
276 *
277 * Small function to shorten the 37 bytes long uuid_t
278 * string representation to 8 characters.
279 */
280 static void shorten_uuid(char *in, char *out)
281 {
282 memcpy(out, in, 8);
283 out[8] = '\0';
284 }
285
286 /*
287 * process_opt_list_sessions
288 *
289 * Get the list of available sessions from
290 * the session daemon and print it to user.
291 */
292 static int process_opt_list_sessions(void)
293 {
294 int ret, count, i;
295 char tmp_short_uuid[9];
296 struct lttng_session *sess;
297
298 count = lttng_list_sessions(&sess);
299 DBG("Session count %d", count);
300 if (count < 0) {
301 ret = count;
302 goto error;
303 }
304
305 MSG("Available sessions (UUIDs):");
306 for (i = 0; i < count; i++) {
307 shorten_uuid(sess[i].uuid, tmp_short_uuid);
308 MSG(" %d) %s.%s", i+1, sess[i].name, tmp_short_uuid);
309 }
310
311 free(sess);
312 MSG("\nTo select a session, use -s, --session UUID.");
313
314 return 0;
315
316 error:
317 return ret;
318 }
319
320 /*
321 * process_opt_list_apps
322 *
323 * Get the UST traceable pid list and print
324 * them to the user.
325 */
326 static int process_opt_list_apps(void)
327 {
328 int i, ret, count;
329 pid_t *pids;
330 char *cmdline;
331
332 count = lttng_ust_list_apps(&pids);
333 if (count < 0) {
334 ret = count;
335 goto error;
336 }
337
338 MSG("LTTng UST traceable application [name (pid)]:");
339 for (i=0; i < count; i++) {
340 cmdline = get_cmdline_by_pid(pids[i]);
341 if (cmdline == NULL) {
342 MSG("\t(not running) (%d)", pids[i]);
343 continue;
344 }
345 MSG("\t%s (%d)", cmdline, pids[i]);
346 free(cmdline);
347 }
348
349 /* Allocated by lttng_ust_list_apps() */
350 free(pids);
351
352 return 0;
353
354 error:
355 return ret;
356 }
357
358 /*
359 * get_cmdline_by_pid
360 *
361 * Get command line from /proc for a specific pid.
362 *
363 * On success, return an allocated string pointer pointing to
364 * the proc cmdline.
365 * On error, return NULL.
366 */
367 static char *get_cmdline_by_pid(pid_t pid)
368 {
369 int ret;
370 FILE *fp;
371 char *cmdline = NULL;
372 char path[24]; /* Can't go bigger than /proc/65535/cmdline */
373
374 snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
375 fp = fopen(path, "r");
376 if (fp == NULL) {
377 goto end;
378 }
379
380 /* Caller must free() *cmdline */
381 cmdline = malloc(PATH_MAX);
382 ret = fread(cmdline, 1, PATH_MAX, fp);
383 fclose(fp);
384
385 end:
386 return cmdline;
387 }
388
389 /*
390 * validate_options
391 *
392 * Make sure that all options passed to the command line
393 * are compatible with each others.
394 *
395 * On error, return -1
396 * On success, return 0
397 */
398 static int validate_options(void)
399 {
400 int ret;
401
402 /* Conflicting command */
403 if (opt_start_trace && opt_stop_trace) {
404 ERR("Can't use --start and --stop together.");
405 goto error;
406 /* Must have a session UUID for trace action. */
407 } else if ((opt_session_uuid == NULL) &&
408 (opt_create_trace || opt_start_trace || opt_stop_trace || opt_list_traces)) {
409 ERR("You need to specify a session UUID.\nPlease use --session UUID to do so.");
410 goto error;
411 /* If no PID specified and trace_kernel is off */
412 } else if ((opt_trace_pid == 0 && opt_trace_kernel == 0) &&
413 (opt_create_trace || opt_start_trace || opt_stop_trace)) {
414 ERR("Please specify a PID using -p, --pid PID.");
415 goto error;
416 }
417
418 if (opt_session_uuid != NULL) {
419 ret = extract_short_uuid(opt_session_uuid, short_uuid);
420 if (ret < 0) {
421 ERR("Session UUID not valid. Must be <name>.<short_uuid>");
422 goto error;
423 }
424 }
425
426 return 0;
427
428 error:
429 return -1;
430 }
431
432 /*
433 * spawn_sessiond
434 *
435 * Spawn a session daemon by forking and execv.
436 */
437 static int spawn_sessiond(char *pathname)
438 {
439 int ret = 0;
440 pid_t pid;
441
442 MSG("Spawning session daemon");
443 pid = fork();
444 if (pid == 0) {
445 /* Spawn session daemon and tell
446 * it to signal us when ready.
447 */
448 ret = execlp(pathname, "ltt-sessiond", "--sig-parent", "--quiet", NULL);
449 if (ret < 0) {
450 if (errno == ENOENT) {
451 ERR("No session daemon found. Use --sessiond-path.");
452 } else {
453 perror("execlp");
454 }
455 kill(getppid(), SIGTERM);
456 exit(EXIT_FAILURE);
457 }
458 exit(EXIT_SUCCESS);
459 } else if (pid > 0) {
460 /* Wait for ltt-sessiond to start */
461 pause();
462 goto end;
463 } else {
464 perror("fork");
465 ret = -1;
466 goto end;
467 }
468
469 end:
470 return ret;
471 }
472
473 /*
474 * check_ltt_sessiond
475 *
476 * Check if the session daemon is available using
477 * the liblttngctl API for the check. If not, try to
478 * spawn a daemon.
479 */
480 static int check_ltt_sessiond(void)
481 {
482 int ret;
483 char *pathname = NULL;
484
485 ret = lttng_check_session_daemon();
486 if (ret < 0) {
487 /* Try command line option path */
488 if (opt_sessiond_path != NULL) {
489 ret = access(opt_sessiond_path, F_OK | X_OK);
490 if (ret < 0) {
491 ERR("No such file: %s", opt_sessiond_path);
492 goto end;
493 }
494 pathname = opt_sessiond_path;
495 } else {
496 /* Try LTTNG_SESSIOND_PATH env variable */
497 pathname = getenv(LTTNG_SESSIOND_PATH_ENV);
498 if (pathname != NULL) {
499 /* strdup here in order to make the free()
500 * not fail later on.
501 */
502 pathname = strdup(pathname);
503 }
504 }
505
506 /* Let's rock and roll */
507 if (pathname == NULL) {
508 ret = asprintf(&pathname, "ltt-sessiond");
509 if (ret < 0) {
510 goto end;
511 }
512 }
513
514 ret = spawn_sessiond(pathname);
515 free(pathname);
516 if (ret < 0) {
517 ERR("Problem occurs when starting %s", pathname);
518 goto end;
519 }
520 }
521
522 end:
523 return ret;
524 }
525
526 /*
527 * set_signal_handler
528 *
529 * Setup signal handler for SIGCHLD and SIGTERM.
530 */
531 static int set_signal_handler(void)
532 {
533 int ret = 0;
534 struct sigaction sa;
535 sigset_t sigset;
536
537 if ((ret = sigemptyset(&sigset)) < 0) {
538 perror("sigemptyset");
539 goto end;
540 }
541
542 sa.sa_handler = sighandler;
543 sa.sa_mask = sigset;
544 sa.sa_flags = 0;
545 if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
546 perror("sigaction");
547 goto end;
548 }
549
550 if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
551 perror("sigaction");
552 goto end;
553 }
554
555 end:
556 return ret;
557 }
558
559 /*
560 * sighandler
561 *
562 * Signal handler for the daemon
563 */
564 static void sighandler(int sig)
565 {
566 switch (sig) {
567 case SIGTERM:
568 DBG("SIGTERM catched");
569 clean_exit(EXIT_FAILURE);
570 break;
571 case SIGCHLD:
572 /* Notify is done */
573 DBG("SIGCHLD catched");
574 break;
575 default:
576 DBG("Unknown signal %d catched", sig);
577 break;
578 }
579
580 return;
581 }
582
583 /*
584 * clean_exit
585 */
586 void clean_exit(int code)
587 {
588 DBG("Clean exit");
589 exit(code);
590 }
591
592 /*
593 * main
594 */
595 int main(int argc, char *argv[])
596 {
597 int ret;
598
599 progname = argv[0] ? argv[0] : "lttng";
600
601 /* For Mathieu Desnoyers aka Dr Tracing */
602 if (strncmp(progname, "drtrace", 7) == 0) {
603 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0);
604 }
605
606 ret = parse_args(argc, (const char **) argv);
607 if (ret < 0) {
608 clean_exit(EXIT_FAILURE);
609 }
610
611 ret = validate_options();
612 if (ret < 0) {
613 return EXIT_FAILURE;
614 }
615
616 ret = set_signal_handler();
617 if (ret < 0) {
618 clean_exit(ret);
619 }
620
621 if (opt_tracing_group != NULL) {
622 DBG("Set tracing group to '%s'", opt_tracing_group);
623 lttng_set_tracing_group(opt_tracing_group);
624 }
625
626 /* If ask for kernel tracing, need root perms */
627 if (opt_trace_kernel) {
628 DBG("Kernel tracing activated");
629 if (getuid() != 0) {
630 ERR("%s must be setuid root", progname);
631 clean_exit(-EPERM);
632 }
633 }
634
635 /* Check if the lttng session daemon is running.
636 * If no, a daemon will be spawned.
637 */
638 if (opt_no_sessiond == 0 && (check_ltt_sessiond() < 0)) {
639 clean_exit(EXIT_FAILURE);
640 }
641
642 ret = process_client_opt();
643 if (ret < 0) {
644 clean_exit(ret);
645 }
646
647 clean_exit(0);
648
649 return 0;
650 }
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