| 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 "liblttsessiondcomm.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 | * send_data_sessiond |
| 51 | * |
| 52 | * Send lttcomm_session_msg to the session daemon. |
| 53 | * |
| 54 | * On success, return 0 |
| 55 | * On error, return error code |
| 56 | */ |
| 57 | static int send_data_sessiond(void) |
| 58 | { |
| 59 | int ret; |
| 60 | |
| 61 | if (!connected) { |
| 62 | ret = -ENOTCONN; |
| 63 | goto end; |
| 64 | } |
| 65 | |
| 66 | ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm)); |
| 67 | |
| 68 | end: |
| 69 | return ret; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * recv_data_sessiond |
| 74 | * |
| 75 | * Receive data from the sessiond socket. |
| 76 | * |
| 77 | * On success, return 0 |
| 78 | * On error, return recv() error code |
| 79 | */ |
| 80 | static int recv_data_sessiond(void *buf, size_t len) |
| 81 | { |
| 82 | int ret; |
| 83 | |
| 84 | if (!connected) { |
| 85 | ret = -ENOTCONN; |
| 86 | goto end; |
| 87 | } |
| 88 | |
| 89 | ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len); |
| 90 | |
| 91 | end: |
| 92 | return ret; |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * Check if the specified group name exist. |
| 97 | * |
| 98 | * If yes return 0, else return -1. |
| 99 | */ |
| 100 | static int check_tracing_group(const char *grp_name) |
| 101 | { |
| 102 | struct group *grp_tracing; /* no free(). See getgrnam(3) */ |
| 103 | gid_t *grp_list; |
| 104 | int grp_list_size, grp_id, i; |
| 105 | int ret = -1; |
| 106 | |
| 107 | /* Get GID of group 'tracing' */ |
| 108 | grp_tracing = getgrnam(grp_name); |
| 109 | if (grp_tracing == NULL) { |
| 110 | /* NULL means not found also. getgrnam(3) */ |
| 111 | if (errno != 0) { |
| 112 | perror("getgrnam"); |
| 113 | } |
| 114 | goto end; |
| 115 | } |
| 116 | |
| 117 | /* Get number of supplementary group IDs */ |
| 118 | grp_list_size = getgroups(0, NULL); |
| 119 | if (grp_list_size < 0) { |
| 120 | perror("getgroups"); |
| 121 | goto end; |
| 122 | } |
| 123 | |
| 124 | /* Alloc group list of the right size */ |
| 125 | grp_list = malloc(grp_list_size * sizeof(gid_t)); |
| 126 | grp_id = getgroups(grp_list_size, grp_list); |
| 127 | if (grp_id < -1) { |
| 128 | perror("getgroups"); |
| 129 | goto free_list; |
| 130 | } |
| 131 | |
| 132 | for (i = 0; i < grp_list_size; i++) { |
| 133 | if (grp_list[i] == grp_tracing->gr_gid) { |
| 134 | ret = 0; |
| 135 | break; |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | free_list: |
| 140 | free(grp_list); |
| 141 | |
| 142 | end: |
| 143 | return ret; |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * Set sessiond socket path by putting it in the global sessiond_sock_path |
| 148 | * variable. |
| 149 | */ |
| 150 | static int set_session_daemon_path(void) |
| 151 | { |
| 152 | int ret; |
| 153 | |
| 154 | /* Are we in the tracing group ? */ |
| 155 | ret = check_tracing_group(tracing_group); |
| 156 | if (ret < 0 && getuid() != 0) { |
| 157 | if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK, |
| 158 | getenv("HOME")) < 0) { |
| 159 | return -ENOMEM; |
| 160 | } |
| 161 | } else { |
| 162 | strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK, |
| 163 | sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK)); |
| 164 | } |
| 165 | |
| 166 | return 0; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Connect to the LTTng session daemon. |
| 171 | * |
| 172 | * On success, return 0. On error, return -1. |
| 173 | */ |
| 174 | static int connect_sessiond(void) |
| 175 | { |
| 176 | int ret; |
| 177 | |
| 178 | ret = set_session_daemon_path(); |
| 179 | if (ret < 0) { |
| 180 | return ret; |
| 181 | } |
| 182 | |
| 183 | /* Connect to the sesssion daemon */ |
| 184 | ret = lttcomm_connect_unix_sock(sessiond_sock_path); |
| 185 | if (ret < 0) { |
| 186 | return ret; |
| 187 | } |
| 188 | |
| 189 | sessiond_socket = ret; |
| 190 | connected = 1; |
| 191 | |
| 192 | return 0; |
| 193 | } |
| 194 | |
| 195 | /* |
| 196 | * Clean disconnect the session daemon. |
| 197 | */ |
| 198 | static int disconnect_sessiond(void) |
| 199 | { |
| 200 | int ret = 0; |
| 201 | |
| 202 | if (connected) { |
| 203 | ret = lttcomm_close_unix_sock(sessiond_socket); |
| 204 | sessiond_socket = 0; |
| 205 | connected = 0; |
| 206 | } |
| 207 | |
| 208 | return ret; |
| 209 | } |
| 210 | |
| 211 | /* |
| 212 | * Reset the session message structure. |
| 213 | */ |
| 214 | static void reset_session_msg(void) |
| 215 | { |
| 216 | memset(&lsm, 0, sizeof(struct lttcomm_session_msg)); |
| 217 | } |
| 218 | |
| 219 | /* |
| 220 | * ask_sessiond |
| 221 | * |
| 222 | * Ask the session daemon a specific command and put the data into buf. |
| 223 | * |
| 224 | * Return size of data (only payload, not header). |
| 225 | */ |
| 226 | static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf) |
| 227 | { |
| 228 | int ret; |
| 229 | size_t size; |
| 230 | void *data = NULL; |
| 231 | |
| 232 | ret = connect_sessiond(); |
| 233 | if (ret < 0) { |
| 234 | goto end; |
| 235 | } |
| 236 | |
| 237 | lsm.cmd_type = lct; |
| 238 | |
| 239 | /* Send command to session daemon */ |
| 240 | ret = send_data_sessiond(); |
| 241 | if (ret < 0) { |
| 242 | goto end; |
| 243 | } |
| 244 | |
| 245 | /* Get header from data transmission */ |
| 246 | ret = recv_data_sessiond(&llm, sizeof(llm)); |
| 247 | if (ret < 0) { |
| 248 | goto end; |
| 249 | } |
| 250 | |
| 251 | /* Check error code if OK */ |
| 252 | if (llm.ret_code != LTTCOMM_OK) { |
| 253 | ret = -llm.ret_code; |
| 254 | goto end; |
| 255 | } |
| 256 | |
| 257 | size = llm.data_size; |
| 258 | if (size == 0) { |
| 259 | ret = 0; |
| 260 | goto end; |
| 261 | } |
| 262 | |
| 263 | data = (void*) malloc(size); |
| 264 | |
| 265 | /* Get payload data */ |
| 266 | ret = recv_data_sessiond(data, size); |
| 267 | if (ret < 0) { |
| 268 | free(data); |
| 269 | goto end; |
| 270 | } |
| 271 | |
| 272 | *buf = data; |
| 273 | ret = size; |
| 274 | |
| 275 | end: |
| 276 | disconnect_sessiond(); |
| 277 | reset_session_msg(); |
| 278 | return ret; |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * Start tracing for all trace of the session. |
| 283 | */ |
| 284 | int lttng_start_tracing(const char *session_name) |
| 285 | { |
| 286 | strncpy(lsm.session_name, session_name, NAME_MAX); |
| 287 | return ask_sessiond(LTTNG_START_TRACE, NULL); |
| 288 | } |
| 289 | |
| 290 | /* |
| 291 | * Stop tracing for all trace of the session. |
| 292 | */ |
| 293 | int lttng_stop_tracing(const char *session_name) |
| 294 | { |
| 295 | strncpy(lsm.session_name, session_name, NAME_MAX); |
| 296 | return ask_sessiond(LTTNG_STOP_TRACE, NULL); |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * lttng_add_context |
| 301 | */ |
| 302 | int lttng_add_context(struct lttng_domain *domain, |
| 303 | struct lttng_event_context *ctx, const char *event_name, |
| 304 | const char *channel_name) |
| 305 | { |
| 306 | int ret; |
| 307 | |
| 308 | if (channel_name != NULL) { |
| 309 | strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX); |
| 310 | } |
| 311 | |
| 312 | if (event_name != NULL) { |
| 313 | strncpy(lsm.u.context.event_name, event_name, NAME_MAX); |
| 314 | } |
| 315 | |
| 316 | memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context)); |
| 317 | |
| 318 | switch (domain->type) { |
| 319 | case LTTNG_DOMAIN_KERNEL: |
| 320 | ret = ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL); |
| 321 | break; |
| 322 | case LTTNG_DOMAIN_UST: |
| 323 | ret = LTTCOMM_NOT_IMPLEMENTED; |
| 324 | break; |
| 325 | default: |
| 326 | ret = LTTCOMM_UNKNOWN_DOMAIN; |
| 327 | break; |
| 328 | }; |
| 329 | |
| 330 | return ret; |
| 331 | } |
| 332 | |
| 333 | /* |
| 334 | * lttng_enable_event |
| 335 | */ |
| 336 | int lttng_enable_event(struct lttng_domain *domain, |
| 337 | struct lttng_event *ev, const char *channel_name) |
| 338 | { |
| 339 | int ret; |
| 340 | |
| 341 | if (channel_name == NULL) { |
| 342 | strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX); |
| 343 | } else { |
| 344 | strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX); |
| 345 | } |
| 346 | |
| 347 | switch (domain->type) { |
| 348 | case LTTNG_DOMAIN_KERNEL: |
| 349 | if (ev == NULL) { |
| 350 | ret = ask_sessiond(LTTNG_KERNEL_ENABLE_ALL_EVENT, NULL); |
| 351 | } else { |
| 352 | memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event)); |
| 353 | ret = ask_sessiond(LTTNG_KERNEL_ENABLE_EVENT, NULL); |
| 354 | } |
| 355 | break; |
| 356 | case LTTNG_DOMAIN_UST: |
| 357 | ret = LTTCOMM_NOT_IMPLEMENTED; |
| 358 | break; |
| 359 | default: |
| 360 | ret = LTTCOMM_UNKNOWN_DOMAIN; |
| 361 | break; |
| 362 | }; |
| 363 | |
| 364 | return ret; |
| 365 | } |
| 366 | |
| 367 | /* |
| 368 | * Disable an event in the kernel tracer. |
| 369 | */ |
| 370 | int lttng_disable_event(struct lttng_domain *domain, const char *name, |
| 371 | const char *channel_name) |
| 372 | { |
| 373 | int ret; |
| 374 | |
| 375 | if (channel_name == NULL) { |
| 376 | strncpy(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX); |
| 377 | } else { |
| 378 | strncpy(lsm.u.disable.channel_name, channel_name, NAME_MAX); |
| 379 | } |
| 380 | |
| 381 | switch (domain->type) { |
| 382 | case LTTNG_DOMAIN_KERNEL: |
| 383 | if (name == NULL) { |
| 384 | ret = ask_sessiond(LTTNG_KERNEL_DISABLE_ALL_EVENT, NULL); |
| 385 | } else { |
| 386 | strncpy(lsm.u.disable.name, name, NAME_MAX); |
| 387 | ret = ask_sessiond(LTTNG_KERNEL_DISABLE_EVENT, NULL); |
| 388 | } |
| 389 | break; |
| 390 | case LTTNG_DOMAIN_UST: |
| 391 | ret = LTTCOMM_NOT_IMPLEMENTED; |
| 392 | break; |
| 393 | default: |
| 394 | ret = LTTCOMM_UNKNOWN_DOMAIN; |
| 395 | break; |
| 396 | }; |
| 397 | |
| 398 | return ret; |
| 399 | } |
| 400 | |
| 401 | /* |
| 402 | * Enable recording for a channel for the kernel tracer. |
| 403 | */ |
| 404 | int lttng_enable_channel(struct lttng_domain *domain, |
| 405 | struct lttng_channel *chan) |
| 406 | { |
| 407 | int ret; |
| 408 | |
| 409 | memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel)); |
| 410 | |
| 411 | switch (domain->type) { |
| 412 | case LTTNG_DOMAIN_KERNEL: |
| 413 | ret = ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL); |
| 414 | break; |
| 415 | case LTTNG_DOMAIN_UST: |
| 416 | ret = LTTCOMM_NOT_IMPLEMENTED; |
| 417 | break; |
| 418 | default: |
| 419 | ret = LTTCOMM_UNKNOWN_DOMAIN; |
| 420 | break; |
| 421 | }; |
| 422 | |
| 423 | return ret; |
| 424 | } |
| 425 | |
| 426 | /* |
| 427 | * Disable recording for the channel for the kernel tracer. |
| 428 | */ |
| 429 | int lttng_disable_channel(struct lttng_domain *domain, const char *name) |
| 430 | { |
| 431 | int ret; |
| 432 | |
| 433 | strncpy(lsm.u.disable.channel_name, name, NAME_MAX); |
| 434 | |
| 435 | switch (domain->type) { |
| 436 | case LTTNG_DOMAIN_KERNEL: |
| 437 | ret = ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL); |
| 438 | break; |
| 439 | case LTTNG_DOMAIN_UST: |
| 440 | ret = LTTCOMM_NOT_IMPLEMENTED; |
| 441 | break; |
| 442 | default: |
| 443 | ret = LTTCOMM_UNKNOWN_DOMAIN; |
| 444 | break; |
| 445 | }; |
| 446 | |
| 447 | return ret; |
| 448 | } |
| 449 | |
| 450 | /* |
| 451 | * List all available events in the kernel. |
| 452 | * |
| 453 | * Return the size (bytes) of the list and set the event_list array. |
| 454 | * On error, return negative value. |
| 455 | */ |
| 456 | int lttng_list_events(struct lttng_domain *domain, char **event_list) |
| 457 | { |
| 458 | int ret; |
| 459 | |
| 460 | switch (domain->type) { |
| 461 | case LTTNG_DOMAIN_KERNEL: |
| 462 | ret = ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) event_list); |
| 463 | break; |
| 464 | case LTTNG_DOMAIN_UST: |
| 465 | ret = LTTCOMM_NOT_IMPLEMENTED; |
| 466 | break; |
| 467 | default: |
| 468 | ret = LTTCOMM_UNKNOWN_DOMAIN; |
| 469 | break; |
| 470 | }; |
| 471 | |
| 472 | return ret; |
| 473 | } |
| 474 | |
| 475 | /* |
| 476 | * Return a human readable string of code |
| 477 | */ |
| 478 | const char *lttng_get_readable_code(int code) |
| 479 | { |
| 480 | if (code > -LTTCOMM_OK) { |
| 481 | return "Ended with errors"; |
| 482 | } |
| 483 | |
| 484 | return lttcomm_get_readable_code(code); |
| 485 | } |
| 486 | |
| 487 | /* |
| 488 | * Create a brand new session using name. |
| 489 | */ |
| 490 | int lttng_create_session(const char *name, const char *path) |
| 491 | { |
| 492 | strncpy(lsm.session_name, name, NAME_MAX); |
| 493 | strncpy(lsm.path, path, PATH_MAX); |
| 494 | return ask_sessiond(LTTNG_CREATE_SESSION, NULL); |
| 495 | } |
| 496 | |
| 497 | /* |
| 498 | * Destroy session using name. |
| 499 | */ |
| 500 | int lttng_destroy_session(const char *name) |
| 501 | { |
| 502 | strncpy(lsm.session_name, name, NAME_MAX); |
| 503 | return ask_sessiond(LTTNG_DESTROY_SESSION, NULL); |
| 504 | } |
| 505 | |
| 506 | /* |
| 507 | * Ask the session daemon for all available sessions. |
| 508 | * |
| 509 | * Return number of session. |
| 510 | * On error, return negative value. |
| 511 | */ |
| 512 | int lttng_list_sessions(struct lttng_session **sessions) |
| 513 | { |
| 514 | int ret; |
| 515 | |
| 516 | ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions); |
| 517 | if (ret < 0) { |
| 518 | return ret; |
| 519 | } |
| 520 | |
| 521 | return ret / sizeof(struct lttng_session); |
| 522 | } |
| 523 | |
| 524 | /* |
| 525 | * Set session name for the current lsm. |
| 526 | */ |
| 527 | void lttng_set_session_name(const char *name) |
| 528 | { |
| 529 | strncpy(lsm.session_name, name, NAME_MAX); |
| 530 | } |
| 531 | |
| 532 | /* |
| 533 | * lttng_set_tracing_group |
| 534 | * |
| 535 | * Set tracing group variable with name. This function |
| 536 | * allocate memory pointed by tracing_group. |
| 537 | */ |
| 538 | int lttng_set_tracing_group(const char *name) |
| 539 | { |
| 540 | if (asprintf(&tracing_group, "%s", name) < 0) { |
| 541 | return -ENOMEM; |
| 542 | } |
| 543 | |
| 544 | return 0; |
| 545 | } |
| 546 | |
| 547 | /* |
| 548 | * lttng_check_session_daemon |
| 549 | * |
| 550 | * Yes, return 1 |
| 551 | * No, return 0 |
| 552 | * Error, return negative value |
| 553 | */ |
| 554 | int lttng_session_daemon_alive(void) |
| 555 | { |
| 556 | int ret; |
| 557 | |
| 558 | ret = set_session_daemon_path(); |
| 559 | if (ret < 0) { |
| 560 | /* Error */ |
| 561 | return ret; |
| 562 | } |
| 563 | |
| 564 | /* If socket exist, we consider the daemon started */ |
| 565 | ret = access(sessiond_sock_path, F_OK); |
| 566 | if (ret < 0) { |
| 567 | /* Not alive */ |
| 568 | return 0; |
| 569 | } |
| 570 | |
| 571 | /* Is alive */ |
| 572 | return 1; |
| 573 | } |
| 574 | |
| 575 | /* |
| 576 | * lib constructor |
| 577 | */ |
| 578 | static void __attribute__((constructor)) init() |
| 579 | { |
| 580 | /* Set default session group */ |
| 581 | lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP); |
| 582 | } |