| 1 | /* |
| 2 | * liblttngctl.c |
| 3 | * |
| 4 | * Linux Trace Toolkit Control Library |
| 5 | * |
| 6 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> |
| 7 | * |
| 8 | * This library is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; only |
| 11 | * version 2.1 of the License. |
| 12 | * |
| 13 | * This library is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with this library; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #define _GNU_SOURCE |
| 24 | #include <errno.h> |
| 25 | #include <grp.h> |
| 26 | #include <stdio.h> |
| 27 | #include <stdlib.h> |
| 28 | #include <string.h> |
| 29 | #include <unistd.h> |
| 30 | |
| 31 | #include <lttng/lttng.h> |
| 32 | |
| 33 | #include <lttng/lttng-sessiond-comm.h> |
| 34 | #include "lttngerr.h" |
| 35 | #include "lttng-share.h" |
| 36 | |
| 37 | /* Socket to session daemon for communication */ |
| 38 | static int sessiond_socket; |
| 39 | static char sessiond_sock_path[PATH_MAX]; |
| 40 | |
| 41 | /* Communication structure to ltt-sessiond */ |
| 42 | static struct lttcomm_session_msg lsm; |
| 43 | static struct lttcomm_lttng_msg llm; |
| 44 | |
| 45 | /* Variables */ |
| 46 | static char *tracing_group; |
| 47 | static int connected; |
| 48 | |
| 49 | /* |
| 50 | * Copy string from src to dst and enforce null terminated byte. |
| 51 | */ |
| 52 | static void copy_string(char *dst, const char *src, size_t len) |
| 53 | { |
| 54 | if (src && dst) { |
| 55 | strncpy(dst, src, len); |
| 56 | /* Enforce the NULL terminated byte */ |
| 57 | dst[len - 1] = '\0'; |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | /* |
| 62 | * send_data_sessiond |
| 63 | * |
| 64 | * Send lttcomm_session_msg to the session daemon. |
| 65 | * |
| 66 | * On success, return 0 |
| 67 | * On error, return error code |
| 68 | */ |
| 69 | static int send_data_sessiond(void) |
| 70 | { |
| 71 | int ret; |
| 72 | |
| 73 | if (!connected) { |
| 74 | ret = -ENOTCONN; |
| 75 | goto end; |
| 76 | } |
| 77 | |
| 78 | ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm)); |
| 79 | |
| 80 | end: |
| 81 | return ret; |
| 82 | } |
| 83 | |
| 84 | /* |
| 85 | * recv_data_sessiond |
| 86 | * |
| 87 | * Receive data from the sessiond socket. |
| 88 | * |
| 89 | * On success, return 0 |
| 90 | * On error, return recv() error code |
| 91 | */ |
| 92 | static int recv_data_sessiond(void *buf, size_t len) |
| 93 | { |
| 94 | int ret; |
| 95 | |
| 96 | if (!connected) { |
| 97 | ret = -ENOTCONN; |
| 98 | goto end; |
| 99 | } |
| 100 | |
| 101 | ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len); |
| 102 | |
| 103 | end: |
| 104 | return ret; |
| 105 | } |
| 106 | |
| 107 | /* |
| 108 | * Check if the specified group name exist. |
| 109 | * |
| 110 | * If yes return 0, else return -1. |
| 111 | */ |
| 112 | static int check_tracing_group(const char *grp_name) |
| 113 | { |
| 114 | struct group *grp_tracing; /* no free(). See getgrnam(3) */ |
| 115 | gid_t *grp_list; |
| 116 | int grp_list_size, grp_id, i; |
| 117 | int ret = -1; |
| 118 | |
| 119 | /* Get GID of group 'tracing' */ |
| 120 | grp_tracing = getgrnam(grp_name); |
| 121 | if (grp_tracing == NULL) { |
| 122 | /* NULL means not found also. getgrnam(3) */ |
| 123 | if (errno != 0) { |
| 124 | perror("getgrnam"); |
| 125 | } |
| 126 | goto end; |
| 127 | } |
| 128 | |
| 129 | /* Get number of supplementary group IDs */ |
| 130 | grp_list_size = getgroups(0, NULL); |
| 131 | if (grp_list_size < 0) { |
| 132 | perror("getgroups"); |
| 133 | goto end; |
| 134 | } |
| 135 | |
| 136 | /* Alloc group list of the right size */ |
| 137 | grp_list = malloc(grp_list_size * sizeof(gid_t)); |
| 138 | grp_id = getgroups(grp_list_size, grp_list); |
| 139 | if (grp_id < -1) { |
| 140 | perror("getgroups"); |
| 141 | goto free_list; |
| 142 | } |
| 143 | |
| 144 | for (i = 0; i < grp_list_size; i++) { |
| 145 | if (grp_list[i] == grp_tracing->gr_gid) { |
| 146 | ret = 0; |
| 147 | break; |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | free_list: |
| 152 | free(grp_list); |
| 153 | |
| 154 | end: |
| 155 | return ret; |
| 156 | } |
| 157 | |
| 158 | /* |
| 159 | * Set sessiond socket path by putting it in the global sessiond_sock_path |
| 160 | * variable. |
| 161 | */ |
| 162 | static int set_session_daemon_path(void) |
| 163 | { |
| 164 | int ret; |
| 165 | |
| 166 | /* Are we in the tracing group ? */ |
| 167 | ret = check_tracing_group(tracing_group); |
| 168 | if (ret < 0 && getuid() != 0) { |
| 169 | if (snprintf(sessiond_sock_path, PATH_MAX, |
| 170 | DEFAULT_HOME_CLIENT_UNIX_SOCK, |
| 171 | getenv("HOME")) < 0) { |
| 172 | return -ENOMEM; |
| 173 | } |
| 174 | } else { |
| 175 | copy_string(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK, |
| 176 | PATH_MAX); |
| 177 | } |
| 178 | |
| 179 | return 0; |
| 180 | } |
| 181 | |
| 182 | /* |
| 183 | * Connect to the LTTng session daemon. |
| 184 | * |
| 185 | * On success, return 0. On error, return -1. |
| 186 | */ |
| 187 | static int connect_sessiond(void) |
| 188 | { |
| 189 | int ret; |
| 190 | |
| 191 | ret = set_session_daemon_path(); |
| 192 | if (ret < 0) { |
| 193 | return ret; |
| 194 | } |
| 195 | |
| 196 | /* Connect to the sesssion daemon */ |
| 197 | ret = lttcomm_connect_unix_sock(sessiond_sock_path); |
| 198 | if (ret < 0) { |
| 199 | return ret; |
| 200 | } |
| 201 | |
| 202 | sessiond_socket = ret; |
| 203 | connected = 1; |
| 204 | |
| 205 | return 0; |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * Clean disconnect the session daemon. |
| 210 | */ |
| 211 | static int disconnect_sessiond(void) |
| 212 | { |
| 213 | int ret = 0; |
| 214 | |
| 215 | if (connected) { |
| 216 | ret = lttcomm_close_unix_sock(sessiond_socket); |
| 217 | sessiond_socket = 0; |
| 218 | connected = 0; |
| 219 | } |
| 220 | |
| 221 | return ret; |
| 222 | } |
| 223 | |
| 224 | /* |
| 225 | * Reset the session message structure. |
| 226 | */ |
| 227 | static void reset_session_msg(void) |
| 228 | { |
| 229 | memset(&lsm, 0, sizeof(struct lttcomm_session_msg)); |
| 230 | } |
| 231 | |
| 232 | /* |
| 233 | * ask_sessiond |
| 234 | * |
| 235 | * Ask the session daemon a specific command and put the data into buf. |
| 236 | * |
| 237 | * Return size of data (only payload, not header). |
| 238 | */ |
| 239 | static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf) |
| 240 | { |
| 241 | int ret; |
| 242 | size_t size; |
| 243 | void *data = NULL; |
| 244 | |
| 245 | ret = connect_sessiond(); |
| 246 | if (ret < 0) { |
| 247 | goto end; |
| 248 | } |
| 249 | |
| 250 | lsm.cmd_type = lct; |
| 251 | |
| 252 | /* Send command to session daemon */ |
| 253 | ret = send_data_sessiond(); |
| 254 | if (ret < 0) { |
| 255 | goto end; |
| 256 | } |
| 257 | |
| 258 | /* Get header from data transmission */ |
| 259 | ret = recv_data_sessiond(&llm, sizeof(llm)); |
| 260 | if (ret < 0) { |
| 261 | goto end; |
| 262 | } |
| 263 | |
| 264 | /* Check error code if OK */ |
| 265 | if (llm.ret_code != LTTCOMM_OK) { |
| 266 | ret = -llm.ret_code; |
| 267 | goto end; |
| 268 | } |
| 269 | |
| 270 | size = llm.data_size; |
| 271 | if (size == 0) { |
| 272 | ret = 0; |
| 273 | goto end; |
| 274 | } |
| 275 | |
| 276 | data = (void*) malloc(size); |
| 277 | |
| 278 | /* Get payload data */ |
| 279 | ret = recv_data_sessiond(data, size); |
| 280 | if (ret < 0) { |
| 281 | free(data); |
| 282 | goto end; |
| 283 | } |
| 284 | |
| 285 | *buf = data; |
| 286 | ret = size; |
| 287 | |
| 288 | end: |
| 289 | disconnect_sessiond(); |
| 290 | reset_session_msg(); |
| 291 | return ret; |
| 292 | } |
| 293 | |
| 294 | /* |
| 295 | * Copy domain to lttcomm_session_msg domain. If unknown domain, default domain |
| 296 | * will be the kernel. |
| 297 | */ |
| 298 | static void copy_lttng_domain(struct lttng_domain *dom) |
| 299 | { |
| 300 | if (dom) { |
| 301 | switch (dom->type) { |
| 302 | case LTTNG_DOMAIN_KERNEL: |
| 303 | case LTTNG_DOMAIN_UST: |
| 304 | case LTTNG_DOMAIN_UST_EXEC_NAME: |
| 305 | case LTTNG_DOMAIN_UST_PID: |
| 306 | case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN: |
| 307 | memcpy(&lsm.domain, dom, sizeof(struct lttng_domain)); |
| 308 | break; |
| 309 | default: |
| 310 | lsm.domain.type = LTTNG_DOMAIN_KERNEL; |
| 311 | break; |
| 312 | } |
| 313 | } |
| 314 | } |
| 315 | |
| 316 | /* |
| 317 | * Start tracing for all trace of the session. |
| 318 | */ |
| 319 | int lttng_start_tracing(const char *session_name) |
| 320 | { |
| 321 | copy_string(lsm.session.name, session_name, NAME_MAX); |
| 322 | return ask_sessiond(LTTNG_START_TRACE, NULL); |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * Stop tracing for all trace of the session. |
| 327 | */ |
| 328 | int lttng_stop_tracing(const char *session_name) |
| 329 | { |
| 330 | copy_string(lsm.session.name, session_name, NAME_MAX); |
| 331 | return ask_sessiond(LTTNG_STOP_TRACE, NULL); |
| 332 | } |
| 333 | |
| 334 | /* |
| 335 | * lttng_add_context |
| 336 | */ |
| 337 | int lttng_add_context(struct lttng_domain *domain, |
| 338 | struct lttng_event_context *ctx, const char *event_name, |
| 339 | const char *channel_name) |
| 340 | { |
| 341 | copy_string(lsm.u.context.channel_name, channel_name, NAME_MAX); |
| 342 | copy_string(lsm.u.context.event_name, event_name, NAME_MAX); |
| 343 | copy_lttng_domain(domain); |
| 344 | |
| 345 | if (ctx) { |
| 346 | memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context)); |
| 347 | } |
| 348 | |
| 349 | return ask_sessiond(LTTNG_ADD_CONTEXT, NULL); |
| 350 | } |
| 351 | |
| 352 | /* |
| 353 | * lttng_enable_event |
| 354 | */ |
| 355 | int lttng_enable_event(struct lttng_domain *domain, |
| 356 | struct lttng_event *ev, const char *channel_name) |
| 357 | { |
| 358 | int ret; |
| 359 | |
| 360 | if (channel_name == NULL) { |
| 361 | copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX); |
| 362 | } else { |
| 363 | copy_string(lsm.u.enable.channel_name, channel_name, NAME_MAX); |
| 364 | } |
| 365 | |
| 366 | copy_lttng_domain(domain); |
| 367 | |
| 368 | if (ev == NULL) { |
| 369 | ret = ask_sessiond(LTTNG_ENABLE_ALL_EVENT, NULL); |
| 370 | } else { |
| 371 | memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event)); |
| 372 | ret = ask_sessiond(LTTNG_ENABLE_EVENT, NULL); |
| 373 | } |
| 374 | |
| 375 | return ret; |
| 376 | } |
| 377 | |
| 378 | /* |
| 379 | * Disable event of a channel and domain. |
| 380 | */ |
| 381 | int lttng_disable_event(struct lttng_domain *domain, const char *name, |
| 382 | const char *channel_name) |
| 383 | { |
| 384 | int ret = -1; |
| 385 | |
| 386 | if (channel_name == NULL) { |
| 387 | copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX); |
| 388 | } else { |
| 389 | copy_string(lsm.u.disable.channel_name, channel_name, NAME_MAX); |
| 390 | } |
| 391 | |
| 392 | copy_lttng_domain(domain); |
| 393 | |
| 394 | if (name == NULL) { |
| 395 | ret = ask_sessiond(LTTNG_DISABLE_ALL_EVENT, NULL); |
| 396 | } else { |
| 397 | copy_string(lsm.u.disable.name, name, NAME_MAX); |
| 398 | ret = ask_sessiond(LTTNG_DISABLE_EVENT, NULL); |
| 399 | } |
| 400 | |
| 401 | return ret; |
| 402 | } |
| 403 | |
| 404 | /* |
| 405 | * Enable channel per domain |
| 406 | */ |
| 407 | int lttng_enable_channel(struct lttng_domain *domain, |
| 408 | struct lttng_channel *chan) |
| 409 | { |
| 410 | if (chan) { |
| 411 | memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel)); |
| 412 | } |
| 413 | |
| 414 | copy_lttng_domain(domain); |
| 415 | |
| 416 | return ask_sessiond(LTTNG_ENABLE_CHANNEL, NULL); |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * All tracing will be stopped for registered events of the channel. |
| 421 | */ |
| 422 | int lttng_disable_channel(struct lttng_domain *domain, const char *name) |
| 423 | { |
| 424 | copy_string(lsm.u.disable.channel_name, name, NAME_MAX); |
| 425 | copy_lttng_domain(domain); |
| 426 | |
| 427 | return ask_sessiond(LTTNG_DISABLE_CHANNEL, NULL); |
| 428 | } |
| 429 | |
| 430 | /* |
| 431 | * List all available tracepoints of domain. |
| 432 | * |
| 433 | * Return the size (bytes) of the list and set the events array. |
| 434 | * On error, return negative value. |
| 435 | */ |
| 436 | int lttng_list_tracepoints(struct lttng_domain *domain, |
| 437 | struct lttng_event **events) |
| 438 | { |
| 439 | int ret; |
| 440 | |
| 441 | copy_lttng_domain(domain); |
| 442 | |
| 443 | ret = ask_sessiond(LTTNG_LIST_TRACEPOINTS, (void **) events); |
| 444 | if (ret < 0) { |
| 445 | return ret; |
| 446 | } |
| 447 | |
| 448 | return ret / sizeof(struct lttng_event); |
| 449 | } |
| 450 | |
| 451 | /* |
| 452 | * Return a human readable string of code |
| 453 | */ |
| 454 | const char *lttng_get_readable_code(int code) |
| 455 | { |
| 456 | if (code > -LTTCOMM_OK) { |
| 457 | return "Ended with errors"; |
| 458 | } |
| 459 | |
| 460 | return lttcomm_get_readable_code(code); |
| 461 | } |
| 462 | |
| 463 | /* |
| 464 | * Create a brand new session using name. |
| 465 | */ |
| 466 | int lttng_create_session(const char *name, const char *path) |
| 467 | { |
| 468 | copy_string(lsm.session.name, name, NAME_MAX); |
| 469 | copy_string(lsm.session.path, path, PATH_MAX); |
| 470 | return ask_sessiond(LTTNG_CREATE_SESSION, NULL); |
| 471 | } |
| 472 | |
| 473 | /* |
| 474 | * Destroy session using name. |
| 475 | */ |
| 476 | int lttng_destroy_session(const char *name) |
| 477 | { |
| 478 | copy_string(lsm.session.name, name, NAME_MAX); |
| 479 | return ask_sessiond(LTTNG_DESTROY_SESSION, NULL); |
| 480 | } |
| 481 | |
| 482 | /* |
| 483 | * Ask the session daemon for all available sessions. |
| 484 | * |
| 485 | * Return number of session. |
| 486 | * On error, return negative value. |
| 487 | */ |
| 488 | int lttng_list_sessions(struct lttng_session **sessions) |
| 489 | { |
| 490 | int ret; |
| 491 | |
| 492 | ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions); |
| 493 | if (ret < 0) { |
| 494 | return ret; |
| 495 | } |
| 496 | |
| 497 | return ret / sizeof(struct lttng_session); |
| 498 | } |
| 499 | |
| 500 | /* |
| 501 | * List domain of a session. |
| 502 | */ |
| 503 | int lttng_list_domains(const char *session_name, struct lttng_domain **domains) |
| 504 | { |
| 505 | int ret; |
| 506 | |
| 507 | copy_string(lsm.session.name, session_name, NAME_MAX); |
| 508 | ret = ask_sessiond(LTTNG_LIST_DOMAINS, (void**) domains); |
| 509 | if (ret < 0) { |
| 510 | return ret; |
| 511 | } |
| 512 | |
| 513 | return ret / sizeof(struct lttng_domain); |
| 514 | } |
| 515 | |
| 516 | /* |
| 517 | * List channels of a session |
| 518 | */ |
| 519 | int lttng_list_channels(struct lttng_domain *domain, |
| 520 | const char *session_name, struct lttng_channel **channels) |
| 521 | { |
| 522 | int ret; |
| 523 | |
| 524 | copy_string(lsm.session.name, session_name, NAME_MAX); |
| 525 | copy_lttng_domain(domain); |
| 526 | |
| 527 | ret = ask_sessiond(LTTNG_LIST_CHANNELS, (void**) channels); |
| 528 | if (ret < 0) { |
| 529 | return ret; |
| 530 | } |
| 531 | |
| 532 | return ret / sizeof(struct lttng_channel); |
| 533 | } |
| 534 | |
| 535 | /* |
| 536 | * List events of a session channel. |
| 537 | */ |
| 538 | int lttng_list_events(struct lttng_domain *domain, |
| 539 | const char *session_name, const char *channel_name, |
| 540 | struct lttng_event **events) |
| 541 | { |
| 542 | int ret; |
| 543 | |
| 544 | copy_string(lsm.session.name, session_name, NAME_MAX); |
| 545 | copy_string(lsm.u.list.channel_name, channel_name, NAME_MAX); |
| 546 | copy_lttng_domain(domain); |
| 547 | |
| 548 | ret = ask_sessiond(LTTNG_LIST_EVENTS, (void**) events); |
| 549 | if (ret < 0) { |
| 550 | return ret; |
| 551 | } |
| 552 | |
| 553 | return ret / sizeof(struct lttng_event); |
| 554 | } |
| 555 | |
| 556 | /* |
| 557 | * Set session name for the current lsm. |
| 558 | */ |
| 559 | void lttng_set_session_name(const char *name) |
| 560 | { |
| 561 | copy_string(lsm.session.name, name, NAME_MAX); |
| 562 | } |
| 563 | |
| 564 | /* |
| 565 | * lttng_set_tracing_group |
| 566 | * |
| 567 | * Set tracing group variable with name. This function |
| 568 | * allocate memory pointed by tracing_group. |
| 569 | */ |
| 570 | int lttng_set_tracing_group(const char *name) |
| 571 | { |
| 572 | if (asprintf(&tracing_group, "%s", name) < 0) { |
| 573 | return -ENOMEM; |
| 574 | } |
| 575 | |
| 576 | return 0; |
| 577 | } |
| 578 | |
| 579 | /* |
| 580 | * lttng_calibrate |
| 581 | */ |
| 582 | int lttng_calibrate(struct lttng_domain *domain, |
| 583 | struct lttng_calibrate *calibrate) |
| 584 | { |
| 585 | int ret; |
| 586 | |
| 587 | copy_lttng_domain(domain); |
| 588 | |
| 589 | memcpy(&lsm.u.calibrate, calibrate, sizeof(struct lttng_calibrate)); |
| 590 | ret = ask_sessiond(LTTNG_CALIBRATE, NULL); |
| 591 | |
| 592 | return ret; |
| 593 | } |
| 594 | |
| 595 | /* |
| 596 | * lttng_check_session_daemon |
| 597 | * |
| 598 | * Yes, return 1 |
| 599 | * No, return 0 |
| 600 | * Error, return negative value |
| 601 | */ |
| 602 | int lttng_session_daemon_alive(void) |
| 603 | { |
| 604 | int ret; |
| 605 | |
| 606 | ret = set_session_daemon_path(); |
| 607 | if (ret < 0) { |
| 608 | /* Error */ |
| 609 | return ret; |
| 610 | } |
| 611 | |
| 612 | /* If socket exist, we check if the daemon listens to connect. */ |
| 613 | ret = access(sessiond_sock_path, F_OK); |
| 614 | if (ret < 0) { |
| 615 | /* Not alive */ |
| 616 | return 0; |
| 617 | } |
| 618 | |
| 619 | ret = lttcomm_connect_unix_sock(sessiond_sock_path); |
| 620 | if (ret < 0) { |
| 621 | /* Not alive */ |
| 622 | return 0; |
| 623 | } |
| 624 | ret = lttcomm_close_unix_sock(ret); |
| 625 | if (ret < 0) |
| 626 | perror("lttcomm_close_unix_sock"); |
| 627 | |
| 628 | /* Is alive */ |
| 629 | return 1; |
| 630 | } |
| 631 | |
| 632 | /* |
| 633 | * lib constructor |
| 634 | */ |
| 635 | static void __attribute__((constructor)) init() |
| 636 | { |
| 637 | /* Set default session group */ |
| 638 | lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP); |
| 639 | } |