Add debug statements to session daemon
[lttng-tools.git] / liblttngctl / liblttngctl.c
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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
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (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
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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17 */
18
19#define _GNU_SOURCE
20#include <errno.h>
21#include <grp.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <unistd.h>
26
27#include <lttng/liblttngctl.h>
28
29#include "liblttsessiondcomm.h"
30#include "lttngerr.h"
31
32/* Socket to session daemon for communication */
33static int sessiond_socket;
34static char sessiond_sock_path[PATH_MAX];
35
36/* Communication structure to ltt-sessiond */
fac6795d 37static struct lttcomm_session_msg lsm;
aaf97519 38static struct lttcomm_lttng_msg llm;
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39
40/* Prototypes */
41static int check_tracing_group(const char *grp_name);
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42static int ask_sessiond(enum lttcomm_command_type lct, void **buf);
43static int recv_data_sessiond(void *buf, size_t len);
44static int send_data_sessiond(void);
fac6795d 45static int set_session_daemon_path(void);
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46
47/* Variables */
48static char *tracing_group;
49static int connected;
50
51/*
ca95a216 52 * send_data_sessiond
fac6795d 53 *
e065084a 54 * Send lttcomm_session_msg to the session daemon.
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55 *
56 * On success, return 0
57 * On error, return error code
58 */
ca95a216 59static int send_data_sessiond(void)
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60{
61 int ret;
62
63 if (!connected) {
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64 ret = -ENOTCONN;
65 goto end;
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66 }
67
68 ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
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69
70end:
71 return ret;
72}
73
74/*
ca95a216 75 * recv_data_sessiond
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76 *
77 * Receive data from the sessiond socket.
78 *
79 * On success, return 0
80 * On error, return recv() error code
81 */
ca95a216 82static int recv_data_sessiond(void *buf, size_t len)
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83{
84 int ret;
85
86 if (!connected) {
87 ret = -ENOTCONN;
88 goto end;
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89 }
90
ca95a216 91 ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
fac6795d 92 if (ret < 0) {
e065084a 93 goto end;
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94 }
95
e065084a 96end:
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97 return ret;
98}
99
100/*
ca95a216 101 * ask_sessiond
fac6795d 102 *
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103 * Ask the session daemon a specific command
104 * and put the data into buf.
105 *
106 * Return size of data (only payload, not header).
fac6795d 107 */
ca95a216 108static int ask_sessiond(enum lttcomm_command_type lct, void **buf)
fac6795d 109{
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110 int ret;
111 size_t size;
112 void *data = NULL;
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113
114 lsm.cmd_type = lct;
115
116 /* Send command to session daemon */
117 ret = send_data_sessiond();
118 if (ret < 0) {
119 goto end;
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120 }
121
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122 /* Get header from data transmission */
123 ret = recv_data_sessiond(&llm, sizeof(llm));
124 if (ret < 0) {
125 goto end;
126 }
fac6795d 127
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128 /* Check error code if OK */
129 if (llm.ret_code != LTTCOMM_OK) {
130 ret = -llm.ret_code;
131 goto end;
132 }
fac6795d 133
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134 size = llm.size_payload;
135 if (size == 0) {
136 goto end;
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137 }
138
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139 data = (void*) malloc(size);
140
141 /* Get payload data */
142 ret = recv_data_sessiond(data, size);
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143 if (ret < 0) {
144 goto end;
145 }
146
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147 *buf = data;
148 ret = size;
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149
150end:
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151 /* Reset lsm data struct */
152 memset(&lsm, 0, sizeof(lsm));
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153 return ret;
154}
155
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156/*
157 * lttng_get_readable_code
158 *
159 * Return a human readable string of code
160 */
161const char *lttng_get_readable_code(int code)
162{
163 if (code > -LTTCOMM_OK) {
164 return "Ended with errors";
165 }
166
167 return lttcomm_get_readable_code(code);
168}
169
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170/*
171 * lttng_ust_start_trace
172 *
173 * Request a trace start for pid.
174 */
175int lttng_ust_start_trace(pid_t pid)
176{
177 int ret;
178
179 lsm.pid = pid;
180 ret = ask_sessiond(UST_START_TRACE, NULL);
181
182 return ret;
183}
184
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185/*
186 * lttng_ust_create_trace
187 *
188 * Request a trace creation for pid.
189 */
190int lttng_ust_create_trace(pid_t pid)
191{
192 int ret;
193
194 lsm.pid = pid;
195 ret = ask_sessiond(UST_CREATE_TRACE, NULL);
196
197 return ret;
198}
199
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200/*
201 * lttng_ust_list_apps
202 *
203 * Ask the session daemon for all UST traceable
204 * applications.
205 *
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206 * Return the number of pids.
207 * On error, return negative value.
fac6795d 208 */
ca95a216 209int lttng_ust_list_apps(pid_t **pids)
fac6795d 210{
ca95a216 211 int ret;
fac6795d 212
ca95a216 213 ret = ask_sessiond(UST_LIST_APPS, (void**) pids);
fac6795d 214 if (ret < 0) {
ca95a216 215 return ret;
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216 }
217
ca95a216 218 return ret / sizeof(pid_t);
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219}
220
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221/*
222 * lttng_create_session
223 *
224 * Create a brand new session using name. Allocate
225 * the session_id param pointing to the UUID.
226 */
8028d920 227int lttng_create_session(char *name, uuid_t *session_id)
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228{
229 int ret;
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230
231 strncpy(lsm.session_name, name, sizeof(lsm.session_name));
8028d920 232 lsm.session_name[sizeof(lsm.session_name) - 1] = '\0';
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233
234 ret = ask_sessiond(LTTNG_CREATE_SESSION, NULL);
235 if (ret < 0) {
236 goto end;
237 }
238
8028d920 239 uuid_copy(*session_id, llm.session_id);
aaf97519 240
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241end:
242 return ret;
243}
244
245/*
246 * lttng_destroy_session
247 *
248 * Destroy session using name.
249 */
250int lttng_destroy_session(uuid_t *uuid)
251{
252 int ret;
253
254 uuid_copy(lsm.session_id, *uuid);
255
256 ret = ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
257 if (ret < 0) {
258 goto end;
259 }
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260
261end:
262 return ret;
263}
264
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265/*
266 * lttng_list_sessions
267 *
268 * Ask the session daemon for all available sessions.
269 *
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270 * Return number of session.
271 * On error, return negative value.
57167058 272 */
ca95a216 273int lttng_list_sessions(struct lttng_session **sessions)
57167058 274{
ca95a216 275 int ret;
57167058 276
ca95a216 277 ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
57167058 278 if (ret < 0) {
ca95a216 279 return ret;
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280 }
281
ca95a216 282 return ret / sizeof(struct lttng_session);
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283}
284
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285/*
286 * lttng_connect_sessiond
287 *
288 * Connect to the LTTng session daemon.
289 * On success, return 0
290 * On error, return a negative value
291 */
292int lttng_connect_sessiond(void)
293{
294 int ret;
295
296 ret = set_session_daemon_path();
297 if (ret < 0) {
298 return ret;
299 }
300
301 /* Connect to the sesssion daemon */
302 ret = lttcomm_connect_unix_sock(sessiond_sock_path);
303 if (ret < 0) {
304 return ret;
305 }
306
307 sessiond_socket = ret;
308 connected = 1;
309
310 return 0;
311}
312
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313/*
314 * lttng_disconnect_sessiond
315 *
316 * Clean disconnect the session daemon.
317 */
318int lttng_disconnect_sessiond(void)
319{
320 int ret = 0;
321
322 if (connected) {
323 ret = lttcomm_close_unix_sock(sessiond_socket);
324 sessiond_socket = 0;
325 connected = 0;
326 }
327
328 return ret;
329}
330
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331/*
332 * lttng_set_current_session_uuid
333 *
334 * Set the session uuid for current lsm.
335 */
336void lttng_set_current_session_uuid(char *uuid)
337{
338 uuid_parse(uuid, lsm.session_id);
339}
340
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341/*
342 * lttng_set_tracing_group
343 *
344 * Set tracing group variable with name. This function
345 * allocate memory pointed by tracing_group.
346 */
347int lttng_set_tracing_group(const char *name)
348{
349 if (asprintf(&tracing_group, "%s", name) < 0) {
350 return -ENOMEM;
351 }
352
353 return 0;
354}
355
356/*
357 * lttng_check_session_daemon
358 *
359 * Return 0 if a sesssion daemon is available
360 * else return -1
361 */
362int lttng_check_session_daemon(void)
363{
364 int ret;
365
366 ret = set_session_daemon_path();
367 if (ret < 0) {
368 return ret;
369 }
370
371 /* If socket exist, we consider the daemon started */
372 ret = access(sessiond_sock_path, F_OK);
373 if (ret < 0) {
374 return ret;
375 }
376
377 return 0;
378}
379
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380/*
381 * set_session_daemon_path
382 *
383 * Set sessiond socket path by putting it in
384 * the global sessiond_sock_path variable.
385 */
386static int set_session_daemon_path(void)
387{
388 int ret;
389
390 /* Are we in the tracing group ? */
391 ret = check_tracing_group(tracing_group);
392 if (ret < 0) {
393 if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
394 getenv("HOME")) < 0) {
395 return -ENOMEM;
396 }
397 } else {
398 strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
399 sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
400 }
401
402 return 0;
403}
404
405/*
406 * check_tracing_group
407 *
408 * Check if the specified group name exist.
409 * If yes, 0, else -1
410 */
411static int check_tracing_group(const char *grp_name)
412{
413 struct group *grp_tracing; /* no free(). See getgrnam(3) */
414 gid_t *grp_list;
415 int grp_list_size, grp_id, i;
416 int ret = -1;
417
418 /* Get GID of group 'tracing' */
419 grp_tracing = getgrnam(grp_name);
420 if (grp_tracing == NULL) {
421 /* NULL means not found also. getgrnam(3) */
422 if (errno != 0) {
423 perror("getgrnam");
424 }
425 goto end;
426 }
427
428 /* Get number of supplementary group IDs */
429 grp_list_size = getgroups(0, NULL);
430 if (grp_list_size < 0) {
431 perror("getgroups");
432 goto end;
433 }
434
435 /* Alloc group list of the right size */
436 grp_list = malloc(grp_list_size * sizeof(gid_t));
437 grp_id = getgroups(grp_list_size, grp_list);
438 if (grp_id < -1) {
439 perror("getgroups");
440 goto free_list;
441 }
442
443 for (i = 0; i < grp_list_size; i++) {
444 if (grp_list[i] == grp_tracing->gr_gid) {
445 ret = 0;
446 break;
447 }
448 }
449
450free_list:
451 free(grp_list);
452
453end:
454 return ret;
455}
456
457/*
458 * lib constructor
459 */
460static void __attribute__((constructor)) init()
461{
462 /* Set default session group */
463 lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
464}
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