Fix: Use after free on spawn_sessiond error path in check_sessiond
[lttng-tools.git] / src / bin / lttng / lttng.c
CommitLineData
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1/*
2 * Copyright (c) 2011 David Goulet <david.goulet@polymtl.ca>
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3 *
4 * This program is free software; you can redistribute it and/or modify
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5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
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7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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16 */
17
18#define _GNU_SOURCE
fac6795d 19#include <getopt.h>
f3ed775e 20#include <signal.h>
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21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
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24#include <sys/types.h>
25#include <sys/wait.h>
fac6795d 26#include <unistd.h>
3bd1e081 27#include <config.h>
730389d9 28#include <ctype.h>
fac6795d 29
5b97ec60 30#include <lttng/lttng.h>
db758600 31#include <common/error.h>
fac6795d 32
c399183f 33#include "command.h"
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34
35/* Variables */
36static char *progname;
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37static int opt_no_sessiond;
38static char *opt_sessiond_path;
8db8d1dc 39static pid_t sessiond_pid;
5a532b68 40static volatile int recv_child_signal;
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41
42enum {
f3ed775e 43 OPT_SESSION_PATH,
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44 OPT_DUMP_OPTIONS,
45 OPT_DUMP_COMMANDS,
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46};
47
48/* Getopt options. No first level command. */
49static struct option long_options[] = {
50 {"help", 0, NULL, 'h'},
51 {"group", 1, NULL, 'g'},
52 {"verbose", 0, NULL, 'v'},
53 {"quiet", 0, NULL, 'q'},
8490ae7b 54 {"no-sessiond", 0, NULL, 'n'},
f3ed775e 55 {"sessiond-path", 1, NULL, OPT_SESSION_PATH},
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56 {"list-options", 0, NULL, OPT_DUMP_OPTIONS},
57 {"list-commands", 0, NULL, OPT_DUMP_COMMANDS},
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58 {NULL, 0, NULL, 0}
59};
60
61/* First level command */
62static struct cmd_struct commands[] = {
63 { "list", cmd_list},
64 { "create", cmd_create},
65 { "destroy", cmd_destroy},
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66 { "start", cmd_start},
67 { "stop", cmd_stop},
68 { "enable-event", cmd_enable_events},
e953ef25 69 { "disable-event", cmd_disable_events},
d36b8583 70 { "enable-channel", cmd_enable_channels},
26cc6b4e 71 { "disable-channel", cmd_disable_channels},
d65106b1 72 { "add-context", cmd_add_context},
3087ef18 73 { "set-session", cmd_set_session},
eb9cb8b7 74 { "version", cmd_version},
d0254c7c 75 { "calibrate", cmd_calibrate},
0c95f5b2 76 { "view", cmd_view},
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77 { "enable-consumer", cmd_enable_consumer}, /* OBSELETE */
78 { "disable-consumer", cmd_disable_consumer}, /*OBSELETE */
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79 { NULL, NULL} /* Array closure */
80};
81
82static void usage(FILE *ofp)
8c0faa1d 83{
c6d4a597 84 fprintf(ofp, "LTTng Trace Control " VERSION" - " VERSION_NAME"\n\n");
32a6298d 85 fprintf(ofp, "usage: lttng [OPTIONS] <COMMAND> [<ARGS>]\n");
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86 fprintf(ofp, "\n");
87 fprintf(ofp, "Options:\n");
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88 fprintf(ofp, " -h, --help Show this help\n");
89 fprintf(ofp, " --list-options Simple listing of lttng options\n");
90 fprintf(ofp, " --list-commands Simple listing of lttng commands\n");
91 fprintf(ofp, " -v, --verbose Increase verbosity\n");
92 fprintf(ofp, " -q, --quiet Quiet mode\n");
93 fprintf(ofp, " -g, --group NAME Unix tracing group name. (default: tracing)\n");
94 fprintf(ofp, " -n, --no-sessiond Don't spawn a session daemon\n");
95 fprintf(ofp, " --sessiond-path PATH Session daemon full path\n");
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96 fprintf(ofp, "\n");
97 fprintf(ofp, "Commands:\n");
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98 fprintf(ofp, " add-context Add context to event and/or channel\n");
99 fprintf(ofp, " calibrate Quantify LTTng overhead\n");
100 fprintf(ofp, " create Create tracing session\n");
101 fprintf(ofp, " destroy Tear down tracing session\n");
102 fprintf(ofp, " enable-channel Enable tracing channel\n");
103 fprintf(ofp, " enable-event Enable tracing event\n");
104 fprintf(ofp, " disable-channel Disable tracing channel\n");
105 fprintf(ofp, " disable-event Disable tracing event\n");
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106 fprintf(ofp, " list List possible tracing options\n");
107 fprintf(ofp, " set-session Set current session name\n");
108 fprintf(ofp, " start Start tracing\n");
109 fprintf(ofp, " stop Stop tracing\n");
110 fprintf(ofp, " version Show version information\n");
111 fprintf(ofp, " view Start trace viewer\n");
f3ed775e 112 fprintf(ofp, "\n");
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113 fprintf(ofp, "Each command also has its own -h, --help option.\n");
114 fprintf(ofp, "\n");
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115 fprintf(ofp, "Please see the lttng(1) man page for full documentation.\n");
116 fprintf(ofp, "See http://lttng.org for updates, bug reports and news.\n");
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117}
118
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119/*
120 * list_options
121 *
122 * List options line by line. This is mostly for bash auto completion and to
123 * avoid difficult parsing.
124 */
125static void list_options(FILE *ofp)
126{
127 int i = 0;
128 struct option *option = NULL;
129
130 option = &long_options[i];
131 while (option->name != NULL) {
132 fprintf(ofp, "--%s\n", option->name);
133
134 if (isprint(option->val)) {
135 fprintf(ofp, "-%c\n", option->val);
136 }
137
138 i++;
139 option = &long_options[i];
140 }
141}
142
143/*
144 * list_commands
145 *
146 * List commands line by line. This is mostly for bash auto completion and to
147 * avoid difficult parsing.
148 */
149static void list_commands(FILE *ofp)
150{
151 int i = 0;
152 struct cmd_struct *cmd = NULL;
153
154 cmd = &commands[i];
155 while (cmd->name != NULL) {
156 fprintf(ofp, "%s\n", cmd->name);
157 i++;
158 cmd = &commands[i];
159 }
160}
161
7442b2ba 162/*
f3ed775e 163 * clean_exit
96243366 164 */
f3ed775e 165static void clean_exit(int code)
96243366 166{
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167 DBG("Clean exit");
168 exit(code);
894be886 169}
96243366 170
894be886 171/*
f3ed775e 172 * sighandler
2ef84c95 173 *
f3ed775e 174 * Signal handler for the daemon
2ef84c95 175 */
f3ed775e 176static void sighandler(int sig)
2ef84c95 177{
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178 int status;
179
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180 switch (sig) {
181 case SIGTERM:
99bab54f 182 DBG("SIGTERM caught");
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183 clean_exit(EXIT_FAILURE);
184 break;
185 case SIGCHLD:
99bab54f 186 DBG("SIGCHLD caught");
8db8d1dc 187 waitpid(sessiond_pid, &status, 0);
5a532b68 188 recv_child_signal = 1;
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189 /* Indicate that the session daemon died */
190 sessiond_pid = 0;
191 ERR("Session daemon died (exit status %d)", WEXITSTATUS(status));
192 break;
193 case SIGUSR1:
194 /* Notify is done */
5a532b68 195 recv_child_signal = 1;
99bab54f 196 DBG("SIGUSR1 caught");
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197 break;
198 default:
99bab54f 199 DBG("Unknown signal %d caught", sig);
f3ed775e 200 break;
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201 }
202
f3ed775e 203 return;
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204}
205
206/*
f3ed775e 207 * set_signal_handler
894be886 208 *
f3ed775e 209 * Setup signal handler for SIGCHLD and SIGTERM.
894be886 210 */
f3ed775e 211static int set_signal_handler(void)
894be886 212{
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213 int ret = 0;
214 struct sigaction sa;
215 sigset_t sigset;
33a2b854 216
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217 if ((ret = sigemptyset(&sigset)) < 0) {
218 perror("sigemptyset");
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219 goto end;
220 }
221
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222 sa.sa_handler = sighandler;
223 sa.sa_mask = sigset;
224 sa.sa_flags = 0;
8db8d1dc 225 if ((ret = sigaction(SIGUSR1, &sa, NULL)) < 0) {
f3ed775e 226 perror("sigaction");
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227 goto end;
228 }
229
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230 if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
231 perror("sigaction");
232 goto end;
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233 }
234
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235 if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
236 perror("sigaction");
237 goto end;
238 }
239
96243366 240end:
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241 return ret;
242}
243
fac6795d 244/*
f3ed775e 245 * handle_command
fac6795d 246 *
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247 * Handle the full argv list of a first level command. Will find the command
248 * in the global commands array and call the function callback associated.
1c9f7941 249 *
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250 * If command not found, return -1
251 * else, return function command error code.
1c9f7941 252 */
f3ed775e 253static int handle_command(int argc, char **argv)
1c9f7941 254{
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255 int i = 0, ret;
256 struct cmd_struct *cmd;
1c9f7941 257
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258 if (*argv == NULL) {
259 ret = CMD_SUCCESS;
47b74d63 260 goto end;
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261 }
262
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263 cmd = &commands[i];
264 while (cmd->func != NULL) {
265 /* Find command */
266 if (strcmp(argv[0], cmd->name) == 0) {
267 ret = cmd->func(argc, (const char**) argv);
f3ed775e 268 goto end;
894be886 269 }
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270 i++;
271 cmd = &commands[i];
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272 }
273
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274 /* Command not found */
275 ret = -1;
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276
277end:
f3ed775e 278 return ret;
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279}
280
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281/*
282 * spawn_sessiond
283 *
284 * Spawn a session daemon by forking and execv.
285 */
286static int spawn_sessiond(char *pathname)
287{
288 int ret = 0;
289 pid_t pid;
290
f3ed775e 291 MSG("Spawning a session daemon");
5a532b68 292 recv_child_signal = 0;
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293 pid = fork();
294 if (pid == 0) {
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295 /*
296 * Spawn session daemon and tell
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297 * it to signal us when ready.
298 */
32258573 299 execlp(pathname, "lttng-sessiond", "--sig-parent", "--quiet", NULL);
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300 /* execlp only returns if error happened */
301 if (errno == ENOENT) {
302 ERR("No session daemon found. Use --sessiond-path.");
303 } else {
304 perror("execlp");
5b8719f5 305 }
5a532b68 306 kill(getppid(), SIGTERM); /* wake parent */
5e16da05 307 exit(EXIT_FAILURE);
5b8719f5 308 } else if (pid > 0) {
8db8d1dc 309 sessiond_pid = pid;
5a532b68 310 /*
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311 * Wait for lttng-sessiond to start. We need to use a flag to check if
312 * the signal has been sent to us, because the child can be scheduled
313 * before the parent, and thus send the signal before this check. In
314 * the signal handler, we set the recv_child_signal flag, so anytime we
315 * check it after the fork is fine. Note that sleep() is interrupted
316 * before the 1 second delay as soon as the signal is received, so it
317 * will not cause visible delay for the user.
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MD
318 */
319 while (!recv_child_signal) {
320 sleep(1);
321 }
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322 /*
323 * The signal handler will nullify sessiond_pid on SIGCHLD
324 */
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325 if (!sessiond_pid) {
326 exit(EXIT_FAILURE);
327 }
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328 goto end;
329 } else {
330 perror("fork");
331 ret = -1;
332 goto end;
333 }
334
335end:
336 return ret;
337}
338
fac6795d 339/*
f3ed775e 340 * check_sessiond
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341 *
342 * Check if the session daemon is available using
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343 * the liblttngctl API for the check. If not, try to
344 * spawn a daemon.
fac6795d 345 */
f3ed775e 346static int check_sessiond(void)
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347{
348 int ret;
5e16da05 349 char *pathname = NULL, *alloc_pathname = NULL;
fac6795d 350
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351 ret = lttng_session_daemon_alive();
352 if (ret == 0) { /* not alive */
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353 /* Try command line option path */
354 if (opt_sessiond_path != NULL) {
355 ret = access(opt_sessiond_path, F_OK | X_OK);
356 if (ret < 0) {
3183dbb0 357 ERR("No such file or access denied: %s", opt_sessiond_path);
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358 goto end;
359 }
360 pathname = opt_sessiond_path;
361 } else {
362 /* Try LTTNG_SESSIOND_PATH env variable */
bbccc3d2 363 pathname = getenv(DEFAULT_SESSIOND_PATH_ENV);
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364 }
365
366 /* Let's rock and roll */
367 if (pathname == NULL) {
32258573 368 ret = asprintf(&alloc_pathname, INSTALL_BIN_PATH "/lttng-sessiond");
5b8719f5 369 if (ret < 0) {
3f5fa9ed 370 perror("asprintf spawn sessiond");
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371 goto end;
372 }
5e16da05 373 pathname = alloc_pathname;
5b8719f5
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374 }
375
376 ret = spawn_sessiond(pathname);
5b8719f5 377 if (ret < 0) {
3183dbb0 378 ERR("Problem occurred when starting %s", pathname);
5b8719f5 379 }
fac6795d 380
c2a79a67
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381 free(alloc_pathname);
382 }
5b8719f5 383end:
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384 return ret;
385}
386
bcfa8a05 387/*
679b4943
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388 * Check args for specific options that *must* not trigger a session daemon
389 * execution.
390 *
391 * Return 1 if match else 0.
bcfa8a05 392 */
679b4943 393static int check_args_no_sessiond(int argc, char **argv)
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394{
395 int i;
396
397 for (i = 0; i < argc; i++) {
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398 if ((strncmp(argv[i], "-h", sizeof("-h")) == 0) ||
399 strncmp(argv[i], "--h", sizeof("--h")) == 0 ||
3183dbb0 400 strncmp(argv[i], "--list-options", sizeof("--list-options")) == 0 ||
4747a49b 401 strncmp(argv[i], "--list-commands", sizeof("--list-commands")) == 0 ||
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402 strncmp(argv[i], "version", sizeof("version")) == 0 ||
403 strncmp(argv[i], "view", sizeof("view")) == 0) {
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404 return 1;
405 }
406 }
407
408 return 0;
409}
410
5b8719f5 411/*
3183dbb0 412 * Parse command line arguments.
5b8719f5 413 *
3183dbb0 414 * Return 0 if OK, else -1
5b8719f5 415 */
f3ed775e 416static int parse_args(int argc, char **argv)
5b8719f5 417{
f3ed775e 418 int opt, ret;
5b8719f5 419
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420 if (argc < 2) {
421 usage(stderr);
422 clean_exit(EXIT_FAILURE);
5b8719f5
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423 }
424
8490ae7b 425 while ((opt = getopt_long(argc, argv, "+hnvqg:", long_options, NULL)) != -1) {
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426 switch (opt) {
427 case 'h':
3183dbb0 428 usage(stdout);
ae856491 429 ret = 0;
3183dbb0 430 goto end;
f3ed775e 431 case 'v':
97e19046 432 lttng_opt_verbose += 1;
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433 break;
434 case 'q':
97e19046 435 lttng_opt_quiet = 1;
f3ed775e
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436 break;
437 case 'g':
438 lttng_set_tracing_group(optarg);
439 break;
8490ae7b 440 case 'n':
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441 opt_no_sessiond = 1;
442 break;
443 case OPT_SESSION_PATH:
444 opt_sessiond_path = strdup(optarg);
445 break;
865abf65
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446 case OPT_DUMP_OPTIONS:
447 list_options(stdout);
448 ret = 0;
3183dbb0 449 goto end;
865abf65
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450 case OPT_DUMP_COMMANDS:
451 list_commands(stdout);
452 ret = 0;
3183dbb0 453 goto end;
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454 default:
455 usage(stderr);
ae856491 456 ret = 1;
f3ed775e
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457 goto error;
458 }
5b8719f5 459 }
fac6795d 460
f3ed775e 461 /* If both options are specified, quiet wins */
97e19046
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462 if (lttng_opt_verbose && lttng_opt_quiet) {
463 lttng_opt_verbose = 0;
5b8719f5
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464 }
465
f3ed775e 466 /* Spawn session daemon if needed */
679b4943 467 if (opt_no_sessiond == 0 && check_args_no_sessiond(argc, argv) == 0 &&
bcfa8a05 468 (check_sessiond() < 0)) {
8005f29a 469 ret = 1;
f3ed775e 470 goto error;
5b8719f5
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471 }
472
f3ed775e
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473 /* No leftovers, print usage and quit */
474 if ((argc - optind) == 0) {
475 usage(stderr);
8005f29a 476 ret = 1;
f3ed775e
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477 goto error;
478 }
7442b2ba 479
f3ed775e
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480 /*
481 * Handle leftovers which is a first level command with the trailing
482 * options.
483 */
484 ret = handle_command(argc - optind, argv + optind);
ae856491
DG
485 switch (ret) {
486 case CMD_WARNING:
487 WARN("Some command(s) went wrong");
488 break;
489 case CMD_ERROR:
490 ERR("Command error");
491 break;
492 case CMD_UNDEFINED:
493 ERR("Undefined command");
494 break;
495 case CMD_FATAL:
496 ERR("Fatal error");
497 break;
498 case -1:
499 usage(stderr);
500 ret = 1;
501 break;
502 case 0:
503 break;
504 default:
42224349
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505 if (ret < 0) {
506 ret = -ret;
507 }
ae856491 508 break;
96243366
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509 }
510
3183dbb0 511end:
f3ed775e 512error:
ae856491 513 return ret;
fac6795d
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514}
515
f3ed775e 516
fac6795d 517/*
5b8719f5 518 * main
fac6795d
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519 */
520int main(int argc, char *argv[])
521{
522 int ret;
cbbb813a 523 char *user;
fac6795d
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524
525 progname = argv[0] ? argv[0] : "lttng";
526
99bab54f 527 /* For Mathieu Desnoyers a.k.a. Dr. Tracing */
cbbb813a
DG
528 user = getenv("USER");
529 if (user != NULL && ((strncmp(progname, "drtrace", 7) == 0 ||
530 strncmp("compudj", user, 7) == 0))) {
4666e71c 531 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n", 27,1,33,27,0);
fac6795d 532 }
cbbb813a 533 /* Thanks Mathieu */
fac6795d 534
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535 ret = set_signal_handler();
536 if (ret < 0) {
87378cf5 537 clean_exit(ret);
5b8719f5
DG
538 }
539
f3ed775e 540 ret = parse_args(argc, argv);
ae856491
DG
541 if (ret != 0) {
542 clean_exit(ret);
1fff1faa 543 }
87378cf5 544
fac6795d
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545 return 0;
546}
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