Initial import of kconsumerd and libkernelctl
[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
5b97ec60 27#include <lttng/lttng.h>
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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;
5461b305 38static struct lttcomm_lttng_msg llm;
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39
40/* Prototypes */
41static int check_tracing_group(const char *grp_name);
6abb15de 42static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf);
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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 */
6abb15de 108static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
fac6795d 109{
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110 int ret;
111 size_t size;
112 void *data = NULL;
ca95a216 113
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114 ret = lttng_connect_sessiond();
115 if (ret < 0) {
116 goto end;
117 }
118
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119 lsm.cmd_type = lct;
120
121 /* Send command to session daemon */
122 ret = send_data_sessiond();
123 if (ret < 0) {
124 goto end;
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125 }
126
ca95a216 127 /* Get header from data transmission */
5461b305 128 ret = recv_data_sessiond(&llm, sizeof(llm));
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129 if (ret < 0) {
130 goto end;
131 }
fac6795d 132
ca95a216 133 /* Check error code if OK */
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134 if (llm.ret_code != LTTCOMM_OK) {
135 ret = -llm.ret_code;
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136 goto end;
137 }
fac6795d 138
5461b305 139 size = llm.trace_name_offset + llm.data_size;
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140 if (size == 0) {
141 goto end;
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142 }
143
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144 data = (void*) malloc(size);
145
146 /* Get payload data */
147 ret = recv_data_sessiond(data, size);
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148 if (ret < 0) {
149 goto end;
150 }
151
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152 *buf = data;
153 ret = size;
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154
155end:
7442b2ba 156 lttng_disconnect_sessiond();
ca95a216 157 memset(&lsm, 0, sizeof(lsm));
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158 return ret;
159}
160
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161/*
162 * lttng_get_readable_code
163 *
164 * Return a human readable string of code
165 */
166const char *lttng_get_readable_code(int code)
167{
168 if (code > -LTTCOMM_OK) {
169 return "Ended with errors";
170 }
171
172 return lttcomm_get_readable_code(code);
173}
174
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175/*
176 * lttng_ust_start_trace
177 *
178 * Request a trace start for pid.
179 */
180int lttng_ust_start_trace(pid_t pid)
181{
182 int ret;
183
184 lsm.pid = pid;
185 ret = ask_sessiond(UST_START_TRACE, NULL);
186
187 return ret;
188}
189
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190/*
191 * lttng_ust_stop_trace
192 *
193 * Request a trace stop for pid.
194 */
195int lttng_ust_stop_trace(pid_t pid)
196{
197 int ret;
198
199 lsm.pid = pid;
200 ret = ask_sessiond(UST_STOP_TRACE, NULL);
201
202 return ret;
203}
204
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205/*
206 * lttng_ust_create_trace
207 *
208 * Request a trace creation for pid.
209 */
210int lttng_ust_create_trace(pid_t pid)
211{
212 int ret;
213
214 lsm.pid = pid;
215 ret = ask_sessiond(UST_CREATE_TRACE, NULL);
216
217 return ret;
218}
219
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220/*
221 * lttng_ust_list_apps
222 *
223 * Ask the session daemon for all UST traceable
224 * applications.
225 *
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226 * Return the number of pids.
227 * On error, return negative value.
fac6795d 228 */
ca95a216 229int lttng_ust_list_apps(pid_t **pids)
fac6795d 230{
ca95a216 231 int ret;
fac6795d 232
ca95a216 233 ret = ask_sessiond(UST_LIST_APPS, (void**) pids);
fac6795d 234 if (ret < 0) {
ca95a216 235 return ret;
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236 }
237
ca95a216 238 return ret / sizeof(pid_t);
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239}
240
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241/*
242 * lttng_list_traces
243 *
244 * Ask the session daemon for all traces (kernel and ust)
245 * for the session identified by uuid.
246 *
247 * Return the number of traces.
248 */
249int lttng_list_traces(uuid_t *uuid, struct lttng_trace **traces)
250{
251 int ret;
252
5461b305 253 uuid_copy(lsm.session_uuid, *uuid);
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254
255 ret = ask_sessiond(LTTNG_LIST_TRACES, (void **) traces);
256 if (ret < 0) {
257 return ret;
258 }
259
260 return ret / sizeof(struct lttng_trace);
261}
262
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263/*
264 * lttng_create_session
265 *
266 * Create a brand new session using name. Allocate
267 * the session_id param pointing to the UUID.
268 */
8028d920 269int lttng_create_session(char *name, uuid_t *session_id)
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270{
271 int ret;
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272
273 strncpy(lsm.session_name, name, sizeof(lsm.session_name));
8028d920 274 lsm.session_name[sizeof(lsm.session_name) - 1] = '\0';
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275
276 ret = ask_sessiond(LTTNG_CREATE_SESSION, NULL);
277 if (ret < 0) {
278 goto end;
279 }
280
5461b305 281 uuid_copy(*session_id, llm.session_uuid);
aaf97519 282
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283end:
284 return ret;
285}
286
287/*
288 * lttng_destroy_session
289 *
290 * Destroy session using name.
291 */
292int lttng_destroy_session(uuid_t *uuid)
293{
294 int ret;
295
5461b305 296 uuid_copy(lsm.session_uuid, *uuid);
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297
298 ret = ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
299 if (ret < 0) {
300 goto end;
301 }
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302
303end:
304 return ret;
305}
306
57167058
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307/*
308 * lttng_list_sessions
309 *
310 * Ask the session daemon for all available sessions.
311 *
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312 * Return number of session.
313 * On error, return negative value.
57167058 314 */
ca95a216 315int lttng_list_sessions(struct lttng_session **sessions)
57167058 316{
ca95a216 317 int ret;
57167058 318
ca95a216 319 ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
57167058 320 if (ret < 0) {
ca95a216 321 return ret;
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322 }
323
ca95a216 324 return ret / sizeof(struct lttng_session);
57167058
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325}
326
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327/*
328 * lttng_connect_sessiond
329 *
330 * Connect to the LTTng session daemon.
331 * On success, return 0
332 * On error, return a negative value
333 */
334int lttng_connect_sessiond(void)
335{
336 int ret;
337
338 ret = set_session_daemon_path();
339 if (ret < 0) {
340 return ret;
341 }
342
343 /* Connect to the sesssion daemon */
344 ret = lttcomm_connect_unix_sock(sessiond_sock_path);
345 if (ret < 0) {
346 return ret;
347 }
348
349 sessiond_socket = ret;
350 connected = 1;
351
352 return 0;
353}
354
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355/*
356 * lttng_disconnect_sessiond
357 *
358 * Clean disconnect the session daemon.
359 */
360int lttng_disconnect_sessiond(void)
361{
362 int ret = 0;
363
364 if (connected) {
365 ret = lttcomm_close_unix_sock(sessiond_socket);
366 sessiond_socket = 0;
367 connected = 0;
368 }
369
370 return ret;
371}
372
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373/*
374 * lttng_set_current_session_uuid
375 *
376 * Set the session uuid for current lsm.
377 */
96243366 378void lttng_set_current_session_uuid(uuid_t *uuid)
e8be5f4f 379{
5461b305 380 uuid_copy(lsm.session_uuid, *uuid);
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381}
382
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383/*
384 * lttng_set_tracing_group
385 *
386 * Set tracing group variable with name. This function
387 * allocate memory pointed by tracing_group.
388 */
389int lttng_set_tracing_group(const char *name)
390{
391 if (asprintf(&tracing_group, "%s", name) < 0) {
392 return -ENOMEM;
393 }
394
395 return 0;
396}
397
398/*
399 * lttng_check_session_daemon
400 *
401 * Return 0 if a sesssion daemon is available
402 * else return -1
403 */
404int lttng_check_session_daemon(void)
405{
406 int ret;
407
408 ret = set_session_daemon_path();
409 if (ret < 0) {
410 return ret;
411 }
412
413 /* If socket exist, we consider the daemon started */
414 ret = access(sessiond_sock_path, F_OK);
415 if (ret < 0) {
416 return ret;
417 }
418
419 return 0;
420}
421
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422/*
423 * set_session_daemon_path
424 *
425 * Set sessiond socket path by putting it in
426 * the global sessiond_sock_path variable.
427 */
428static int set_session_daemon_path(void)
429{
430 int ret;
431
432 /* Are we in the tracing group ? */
433 ret = check_tracing_group(tracing_group);
847177cd 434 if (ret < 0 && getuid() != 0) {
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435 if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
436 getenv("HOME")) < 0) {
437 return -ENOMEM;
438 }
439 } else {
440 strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
441 sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
442 }
443
444 return 0;
445}
446
447/*
448 * check_tracing_group
449 *
450 * Check if the specified group name exist.
451 * If yes, 0, else -1
452 */
453static int check_tracing_group(const char *grp_name)
454{
455 struct group *grp_tracing; /* no free(). See getgrnam(3) */
456 gid_t *grp_list;
457 int grp_list_size, grp_id, i;
458 int ret = -1;
459
460 /* Get GID of group 'tracing' */
461 grp_tracing = getgrnam(grp_name);
462 if (grp_tracing == NULL) {
463 /* NULL means not found also. getgrnam(3) */
464 if (errno != 0) {
465 perror("getgrnam");
466 }
467 goto end;
468 }
469
470 /* Get number of supplementary group IDs */
471 grp_list_size = getgroups(0, NULL);
472 if (grp_list_size < 0) {
473 perror("getgroups");
474 goto end;
475 }
476
477 /* Alloc group list of the right size */
478 grp_list = malloc(grp_list_size * sizeof(gid_t));
479 grp_id = getgroups(grp_list_size, grp_list);
480 if (grp_id < -1) {
481 perror("getgroups");
482 goto free_list;
483 }
484
485 for (i = 0; i < grp_list_size; i++) {
486 if (grp_list[i] == grp_tracing->gr_gid) {
487 ret = 0;
488 break;
489 }
490 }
491
492free_list:
493 free(grp_list);
494
495end:
496 return ret;
497}
498
499/*
500 * lib constructor
501 */
502static void __attribute__((constructor)) init()
503{
504 /* Set default session group */
505 lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
506}
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