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826d496d MD |
1 | /* |
2 | * Copyright (c) 2011 David Goulet <david.goulet@polymtl.ca> | |
fac6795d DG |
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. | |
fac6795d DG |
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/liblttngctl.h> | |
34 | ||
35 | #include "lttng.h" | |
36 | #include "lttngerr.h" | |
37 | ||
38 | /* Variables */ | |
39 | static char *progname; | |
40 | ||
41 | /* Prototypes */ | |
42 | static int process_client_opt(void); | |
43 | static int process_opt_list_apps(void); | |
57167058 | 44 | static int process_opt_list_sessions(void); |
5b8719f5 DG |
45 | static void sighandler(int sig); |
46 | static int set_signal_handler(void); | |
fac6795d DG |
47 | |
48 | /* | |
49 | * start_client | |
50 | * | |
51 | * Process client request from the command line | |
52 | * options. Every tracing action is done by the | |
53 | * liblttngctl API. | |
54 | */ | |
55 | static int process_client_opt(void) | |
56 | { | |
57 | int ret; | |
58 | ||
59 | /* Connect to the session daemon */ | |
60 | ret = lttng_connect_sessiond(); | |
61 | if (ret < 0) { | |
fac6795d DG |
62 | goto end; |
63 | } | |
64 | ||
65 | if (opt_list_apps) { | |
66 | ret = process_opt_list_apps(); | |
67 | if (ret < 0) { | |
fac6795d DG |
68 | goto end; |
69 | } | |
70 | } | |
71 | ||
57167058 DG |
72 | if (opt_list_session) { |
73 | ret = process_opt_list_sessions(); | |
74 | if (ret < 0) { | |
75 | goto end; | |
76 | } | |
77 | } | |
78 | ||
fac6795d DG |
79 | return 0; |
80 | ||
81 | end: | |
ebafd2a5 | 82 | ERR("%s", lttng_get_readable_code(ret)); |
fac6795d DG |
83 | return ret; |
84 | } | |
85 | ||
57167058 DG |
86 | /* |
87 | * process_opt_list_sessions | |
88 | * | |
89 | * Get the list of available sessions from | |
90 | * the session daemon and print it to user. | |
91 | */ | |
92 | static int process_opt_list_sessions(void) | |
93 | { | |
94 | int ret, count, i; | |
95 | struct lttng_session *sess; | |
96 | ||
97 | count = lttng_list_sessions(&sess); | |
98 | if (count < 0) { | |
99 | ret = count; | |
100 | goto error; | |
101 | } | |
102 | ||
103 | MSG("Available sessions [Name (uuid)]:"); | |
104 | for (i = 0; i < count; i++) { | |
105 | MSG("\tName: %s (uuid: %s)", sess[i].name, sess[i].uuid); | |
106 | } | |
107 | ||
108 | free(sess); | |
109 | MSG("\nTo select a session, use --session UUID."); | |
110 | ||
111 | return 0; | |
112 | ||
113 | error: | |
114 | return ret; | |
115 | } | |
116 | ||
fac6795d DG |
117 | /* |
118 | * process_opt_list_apps | |
119 | * | |
120 | * Get the UST traceable pid list and print | |
121 | * them to the user. | |
122 | */ | |
123 | static int process_opt_list_apps(void) | |
124 | { | |
125 | int i, ret; | |
126 | pid_t *pids; | |
127 | FILE *fp; | |
128 | char path[24]; /* Can't go bigger than /proc/65535/cmdline */ | |
129 | char cmdline[PATH_MAX]; | |
130 | ||
131 | ret = lttng_ust_list_apps(&pids); | |
132 | if (ret < 0) { | |
133 | goto error; | |
134 | } | |
135 | ||
136 | MSG("LTTng UST traceable application [name (pid)]:"); | |
137 | for (i=0; i < ret; i++) { | |
138 | snprintf(path, sizeof(path), "/proc/%d/cmdline", pids[i]); | |
139 | fp = fopen(path, "r"); | |
140 | if (fp == NULL) { | |
141 | continue; | |
142 | } | |
143 | ret = fread(cmdline, 1, sizeof(cmdline), fp); | |
144 | MSG("\t%s (%d)", cmdline, pids[i]); | |
145 | fclose(fp); | |
146 | } | |
147 | ||
e065084a DG |
148 | /* Allocated by lttng_ust_list_apps() */ |
149 | free(pids); | |
150 | ||
fac6795d DG |
151 | return 0; |
152 | ||
153 | error: | |
154 | return ret; | |
155 | } | |
156 | ||
5b8719f5 DG |
157 | /* |
158 | * spawn_sessiond | |
159 | * | |
160 | * Spawn a session daemon by forking and execv. | |
161 | */ | |
162 | static int spawn_sessiond(char *pathname) | |
163 | { | |
164 | int ret = 0; | |
165 | pid_t pid; | |
166 | ||
167 | MSG("Spawning session daemon"); | |
168 | pid = fork(); | |
169 | if (pid == 0) { | |
170 | /* Spawn session daemon and tell | |
171 | * it to signal us when ready. | |
172 | */ | |
173 | ret = execlp(pathname, "ltt-sessiond", "--sig-parent", NULL); | |
174 | if (ret < 0) { | |
175 | if (errno == ENOENT) { | |
176 | ERR("No session daemon found. Use --sessiond-path."); | |
177 | } else { | |
178 | perror("execlp"); | |
179 | } | |
180 | kill(getppid(), SIGTERM); | |
181 | exit(EXIT_FAILURE); | |
182 | } | |
183 | exit(EXIT_SUCCESS); | |
184 | } else if (pid > 0) { | |
185 | /* Wait for ltt-sessiond to start */ | |
186 | pause(); | |
187 | goto end; | |
188 | } else { | |
189 | perror("fork"); | |
190 | ret = -1; | |
191 | goto end; | |
192 | } | |
193 | ||
194 | end: | |
195 | return ret; | |
196 | } | |
197 | ||
fac6795d DG |
198 | /* |
199 | * check_ltt_sessiond | |
200 | * | |
201 | * Check if the session daemon is available using | |
5b8719f5 DG |
202 | * the liblttngctl API for the check. If not, try to |
203 | * spawn a daemon. | |
fac6795d DG |
204 | */ |
205 | static int check_ltt_sessiond(void) | |
206 | { | |
207 | int ret; | |
5b8719f5 | 208 | char *pathname = NULL; |
fac6795d DG |
209 | |
210 | ret = lttng_check_session_daemon(); | |
211 | if (ret < 0) { | |
5b8719f5 DG |
212 | /* Try command line option path */ |
213 | if (opt_sessiond_path != NULL) { | |
214 | ret = access(opt_sessiond_path, F_OK | X_OK); | |
215 | if (ret < 0) { | |
216 | ERR("No such file: %s", opt_sessiond_path); | |
217 | goto end; | |
218 | } | |
219 | pathname = opt_sessiond_path; | |
220 | } else { | |
221 | /* Try LTTNG_SESSIOND_PATH env variable */ | |
222 | pathname = strdup(getenv(LTTNG_SESSIOND_PATH_ENV)); | |
223 | } | |
224 | ||
225 | /* Let's rock and roll */ | |
226 | if (pathname == NULL) { | |
227 | ret = asprintf(&pathname, "ltt-sessiond"); | |
228 | if (ret < 0) { | |
229 | goto end; | |
230 | } | |
231 | } | |
232 | ||
233 | ret = spawn_sessiond(pathname); | |
234 | free(pathname); | |
235 | if (ret < 0) { | |
236 | ERR("Problem occurs when starting %s", pathname); | |
237 | goto end; | |
238 | } | |
fac6795d DG |
239 | } |
240 | ||
5b8719f5 | 241 | end: |
fac6795d DG |
242 | return ret; |
243 | } | |
244 | ||
5b8719f5 DG |
245 | /* |
246 | * set_signal_handler | |
247 | * | |
248 | * Setup signal handler for SIGCHLD and SIGTERM. | |
249 | */ | |
250 | static int set_signal_handler(void) | |
251 | { | |
252 | int ret = 0; | |
253 | struct sigaction sa; | |
254 | sigset_t sigset; | |
255 | ||
256 | if ((ret = sigemptyset(&sigset)) < 0) { | |
257 | perror("sigemptyset"); | |
258 | goto end; | |
259 | } | |
260 | ||
261 | sa.sa_handler = sighandler; | |
262 | sa.sa_mask = sigset; | |
263 | sa.sa_flags = 0; | |
264 | if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) { | |
265 | perror("sigaction"); | |
266 | goto end; | |
267 | } | |
fac6795d | 268 | |
5b8719f5 DG |
269 | if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) { |
270 | perror("sigaction"); | |
271 | goto end; | |
272 | } | |
273 | ||
274 | end: | |
275 | return ret; | |
276 | } | |
277 | ||
278 | /* | |
279 | * sighandler | |
280 | * | |
281 | * Signal handler for the daemon | |
282 | */ | |
283 | static void sighandler(int sig) | |
284 | { | |
285 | DBG("%d received", sig); | |
286 | switch (sig) { | |
287 | case SIGTERM: | |
288 | clean_exit(EXIT_FAILURE); | |
289 | break; | |
290 | case SIGCHLD: | |
291 | /* Notify is done */ | |
292 | break; | |
293 | default: | |
294 | break; | |
295 | } | |
296 | ||
297 | return; | |
298 | } | |
fac6795d DG |
299 | /* |
300 | * clean_exit | |
301 | */ | |
302 | void clean_exit(int code) | |
303 | { | |
304 | DBG("Clean exit"); | |
305 | exit(code); | |
306 | } | |
307 | ||
308 | /* | |
5b8719f5 | 309 | * main |
fac6795d DG |
310 | */ |
311 | int main(int argc, char *argv[]) | |
312 | { | |
313 | int ret; | |
314 | ||
315 | progname = argv[0] ? argv[0] : "lttng"; | |
316 | ||
317 | /* For Mathieu Desnoyers aka Dr Tracing */ | |
318 | if (strncmp(progname, "drtrace", 7) == 0) { | |
319 | MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0); | |
320 | } | |
321 | ||
322 | ret = parse_args(argc, (const char **) argv); | |
323 | if (ret < 0) { | |
324 | return EXIT_FAILURE; | |
325 | } | |
326 | ||
5b8719f5 DG |
327 | ret = set_signal_handler(); |
328 | if (ret < 0) { | |
329 | return ret; | |
330 | } | |
331 | ||
fac6795d DG |
332 | if (opt_tracing_group != NULL) { |
333 | DBG("Set tracing group to '%s'", opt_tracing_group); | |
334 | lttng_set_tracing_group(opt_tracing_group); | |
335 | } | |
336 | ||
337 | /* If ask for kernel tracing, need root perms */ | |
338 | if (opt_trace_kernel) { | |
339 | DBG("Kernel tracing activated"); | |
340 | if (getuid() != 0) { | |
341 | ERR("%s must be setuid root", progname); | |
342 | return -EPERM; | |
343 | } | |
344 | } | |
345 | ||
346 | /* Check if the lttng session daemon is running. | |
347 | * If no, a daemon will be spawned. | |
348 | */ | |
5b8719f5 | 349 | if (opt_no_sessiond == 0 && (check_ltt_sessiond() < 0)) { |
fac6795d DG |
350 | return EXIT_FAILURE; |
351 | } | |
352 | ||
353 | ret = process_client_opt(); | |
354 | if (ret < 0) { | |
355 | return ret; | |
356 | } | |
357 | ||
358 | return 0; | |
359 | } |