src/lib/lttng-ctl/lttng-ctl.c

   1 /*
   2  * lttng-ctl.c
   3  *
   4  * Linux Trace Toolkit Control Library
   5  *
   6  * Copyright (C) 2011 EfficiOS Inc.
   7  * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8  *
   9  * SPDX-License-Identifier: LGPL-2.1-only
  10  *
  11  */
  12
  13 #define _LGPL_SOURCE
  14 #include <assert.h>
  15 #include <grp.h>
  16 #include <errno.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <stdint.h>
  20 #include <string.h>
  21 #include <unistd.h>
  22
  23 #include <common/buffer-view.h>
  24 #include <common/common.h>
  25 #include <common/compat/string.h>
  26 #include <common/defaults.h>
  27 #include <common/dynamic-array.h>
  28 #include <common/dynamic-buffer.h>
  29 #include <common/macros.h>
  30 #include <common/sessiond-comm/sessiond-comm.h>
  31 #include <common/tracker.h>
  32 #include <common/uri.h>
  33 #include <common/utils.h>
  34 #include <lttng/channel-internal.h>
  35 #include <lttng/destruction-handle.h>
  36 #include <lttng/endpoint.h>
  37 #include <lttng/event-internal.h>
  38 #include <lttng/health-internal.h>
  39 #include <lttng/lttng.h>
  40 #include <lttng/session-descriptor-internal.h>
  41 #include <lttng/session-internal.h>
  42 #include <lttng/trigger/trigger-internal.h>
  43 #include <lttng/userspace-probe-internal.h>
  44
  45 #include "filter/filter-ast.h"
  46 #include "filter/filter-parser.h"
  47 #include "filter/filter-bytecode.h"
  48 #include "filter/memstream.h"
  49 #include "lttng-ctl-helper.h"
  50
  51 #ifdef DEBUG
  52 static const int print_xml = 1;
  53 #define dbg_printf(fmt, args...)        \
  54         printf("[debug liblttng-ctl] " fmt, ## args)
  55 #else
  56 static const int print_xml = 0;
  57 #define dbg_printf(fmt, args...)                                \
  58 do {                                                            \
  59         /* do nothing but check printf format */                \
  60         if (0)                                                  \
  61                 printf("[debug liblttnctl] " fmt, ## args);     \
  62 } while (0)
  63 #endif
  64
  65 #define COPY_DOMAIN_PACKED(dst, src)                            \
  66 do {                                                            \
  67         struct lttng_domain _tmp_domain;                        \
  68                                                                 \
  69         lttng_ctl_copy_lttng_domain(&_tmp_domain, &src);        \
  70         dst = _tmp_domain;                                      \
  71 } while (0)
  72
  73 /* Socket to session daemon for communication */
  74 static int sessiond_socket = -1;
  75 static char sessiond_sock_path[PATH_MAX];
  76
  77 /* Variables */
  78 static char *tracing_group;
  79 static int connected;
  80
  81 /* Global */
  82
  83 /*
  84  * Those two variables are used by error.h to silent or control the verbosity of
  85  * error message. They are global to the library so application linking with it
  86  * are able to compile correctly and also control verbosity of the library.
  87  */
  88 int lttng_opt_quiet;
  89 int lttng_opt_verbose;
  90 int lttng_opt_mi;
  91
  92 /*
  93  * Copy domain to lttcomm_session_msg domain.
  94  *
  95  * If domain is unknown, default domain will be the kernel.
  96  */
  97 LTTNG_HIDDEN
  98 void lttng_ctl_copy_lttng_domain(struct lttng_domain *dst,
  99                 struct lttng_domain *src)
 100 {
 101         if (src && dst) {
 102                 switch (src->type) {
 103                 case LTTNG_DOMAIN_KERNEL:
 104                 case LTTNG_DOMAIN_UST:
 105                 case LTTNG_DOMAIN_JUL:
 106                 case LTTNG_DOMAIN_LOG4J:
 107                 case LTTNG_DOMAIN_PYTHON:
 108                         memcpy(dst, src, sizeof(struct lttng_domain));
 109                         break;
 110                 default:
 111                         memset(dst, 0, sizeof(struct lttng_domain));
 112                         break;
 113                 }
 114         }
 115 }
 116
 117 /*
 118  * Send lttcomm_session_msg to the session daemon.
 119  *
 120  * On success, returns the number of bytes sent (>=0)
 121  * On error, returns -1
 122  */
 123 static int send_session_msg(struct lttcomm_session_msg *lsm)
 124 {
 125         int ret;
 126
 127         if (!connected) {
 128                 ret = -LTTNG_ERR_NO_SESSIOND;
 129                 goto end;
 130         }
 131
 132         DBG("LSM cmd type : %d", lsm->cmd_type);
 133
 134         ret = lttcomm_send_creds_unix_sock(sessiond_socket, lsm,
 135                         sizeof(struct lttcomm_session_msg));
 136         if (ret < 0) {
 137                 ret = -LTTNG_ERR_FATAL;
 138         }
 139
 140 end:
 141         return ret;
 142 }
 143
 144 /*
 145  * Send var len data to the session daemon.
 146  *
 147  * On success, returns the number of bytes sent (>=0)
 148  * On error, returns -1
 149  */
 150 static int send_session_varlen(const void *data, size_t len)
 151 {
 152         int ret;
 153
 154         if (!connected) {
 155                 ret = -LTTNG_ERR_NO_SESSIOND;
 156                 goto end;
 157         }
 158
 159         if (!data || !len) {
 160                 ret = 0;
 161                 goto end;
 162         }
 163
 164         ret = lttcomm_send_unix_sock(sessiond_socket, data, len);
 165         if (ret < 0) {
 166                 ret = -LTTNG_ERR_FATAL;
 167         }
 168
 169 end:
 170         return ret;
 171 }
 172
 173 /*
 174  * Send file descriptors to the session daemon.
 175  *
 176  * On success, returns the number of bytes sent (>=0)
 177  * On error, returns -1
 178  */
 179 static int send_session_fds(const int *fds, size_t nb_fd)
 180 {
 181         int ret;
 182
 183         if (!connected) {
 184                 ret = -LTTNG_ERR_NO_SESSIOND;
 185                 goto end;
 186         }
 187
 188         if (!fds || !nb_fd) {
 189                 ret = 0;
 190                 goto end;
 191         }
 192
 193         ret = lttcomm_send_fds_unix_sock(sessiond_socket, fds, nb_fd);
 194         if (ret < 0) {
 195                 ret = -LTTNG_ERR_FATAL;
 196         }
 197
 198 end:
 199         return ret;
 200 }
 201
 202 /*
 203  * Receive data from the sessiond socket.
 204  *
 205  * On success, returns the number of bytes received (>=0)
 206  * On error, returns -1 (recvmsg() error) or -ENOTCONN
 207  */
 208 static int recv_data_sessiond(void *buf, size_t len)
 209 {
 210         int ret;
 211
 212         if (!connected) {
 213                 ret = -LTTNG_ERR_NO_SESSIOND;
 214                 goto end;
 215         }
 216
 217         ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
 218         if (ret < 0) {
 219                 ret = -LTTNG_ERR_FATAL;
 220         }
 221
 222 end:
 223         return ret;
 224 }
 225
 226 /*
 227  * Check if we are in the specified group.
 228  *
 229  * If yes return 1, else return -1.
 230  */
 231 LTTNG_HIDDEN
 232 int lttng_check_tracing_group(void)
 233 {
 234         gid_t *grp_list, tracing_gid;
 235         int grp_list_size, grp_id, i;
 236         int ret = -1;
 237         const char *grp_name = tracing_group;
 238
 239         /* Get GID of group 'tracing' */
 240         if (utils_get_group_id(grp_name, false, &tracing_gid)) {
 241                 /* If grp_tracing is NULL, the group does not exist. */
 242                 goto end;
 243         }
 244
 245         /* Get number of supplementary group IDs */
 246         grp_list_size = getgroups(0, NULL);
 247         if (grp_list_size < 0) {
 248                 PERROR("getgroups");
 249                 goto end;
 250         }
 251
 252         /* Alloc group list of the right size */
 253         grp_list = zmalloc(grp_list_size * sizeof(gid_t));
 254         if (!grp_list) {
 255                 PERROR("malloc");
 256                 goto end;
 257         }
 258         grp_id = getgroups(grp_list_size, grp_list);
 259         if (grp_id < 0) {
 260                 PERROR("getgroups");
 261                 goto free_list;
 262         }
 263
 264         for (i = 0; i < grp_list_size; i++) {
 265                 if (grp_list[i] == tracing_gid) {
 266                         ret = 1;
 267                         break;
 268                 }
 269         }
 270
 271 free_list:
 272         free(grp_list);
 273
 274 end:
 275         return ret;
 276 }
 277
 278 static enum lttng_error_code check_enough_available_memory(
 279                 uint64_t num_bytes_requested_per_cpu)
 280 {
 281         int ret;
 282         long num_cpu;
 283         uint64_t best_mem_info;
 284         uint64_t num_bytes_requested_total;
 285
 286         /*
 287          * Get the number of CPU currently online to compute the amount of
 288          * memory needed to create a buffer for every CPU.
 289          */
 290         num_cpu = sysconf(_SC_NPROCESSORS_ONLN);
 291         if (num_cpu == -1) {
 292                 ret = LTTNG_ERR_FATAL;
 293                 goto end;
 294         }
 295
 296         if (num_bytes_requested_per_cpu > UINT64_MAX / (uint64_t) num_cpu) {
 297                 /* Overflow */
 298                 ret = LTTNG_ERR_OVERFLOW;
 299                 goto end;
 300         }
 301
 302         num_bytes_requested_total =
 303                         num_bytes_requested_per_cpu * (uint64_t) num_cpu;
 304
 305         /*
 306          * Try to get the `MemAvail` field of `/proc/meminfo`. This is the most
 307          * reliable estimate we can get but it is only exposed by the kernel
 308          * since 3.14. (See Linux kernel commit:
 309          * 34e431b0ae398fc54ea69ff85ec700722c9da773)
 310          */
 311         ret = utils_get_memory_available(&best_mem_info);
 312         if (ret >= 0) {
 313                 goto success;
 314         }
 315
 316         /*
 317          * As a backup plan, use `MemTotal` field of `/proc/meminfo`. This
 318          * is a sanity check for obvious user error.
 319          */
 320         ret = utils_get_memory_total(&best_mem_info);
 321         if (ret >= 0) {
 322                 goto success;
 323         }
 324
 325         /* No valid source of information. */
 326         ret = LTTNG_ERR_NOMEM;
 327         goto end;
 328
 329 success:
 330         if (best_mem_info >= num_bytes_requested_total) {
 331                 ret = LTTNG_OK;
 332         } else {
 333                 ret = LTTNG_ERR_NOMEM;
 334         }
 335 end:
 336         return ret;
 337 }
 338
 339 /*
 340  * Try connect to session daemon with sock_path.
 341  *
 342  * Return 0 on success, else -1
 343  */
 344 static int try_connect_sessiond(const char *sock_path)
 345 {
 346         int ret;
 347
 348         /* If socket exist, we check if the daemon listens for connect. */
 349         ret = access(sock_path, F_OK);
 350         if (ret < 0) {
 351                 /* Not alive */
 352                 goto error;
 353         }
 354
 355         ret = lttcomm_connect_unix_sock(sock_path);
 356         if (ret < 0) {
 357                 /* Not alive. */
 358                 goto error;
 359         }
 360
 361         ret = lttcomm_close_unix_sock(ret);
 362         if (ret < 0) {
 363                 PERROR("lttcomm_close_unix_sock");
 364         }
 365
 366         return 0;
 367
 368 error:
 369         return -1;
 370 }
 371
 372 /*
 373  * Set sessiond socket path by putting it in the global sessiond_sock_path
 374  * variable.
 375  *
 376  * Returns 0 on success, negative value on failure (the sessiond socket path
 377  * is somehow too long or ENOMEM).
 378  */
 379 static int set_session_daemon_path(void)
 380 {
 381         int in_tgroup = 0;      /* In tracing group. */
 382         uid_t uid;
 383
 384         uid = getuid();
 385
 386         if (uid != 0) {
 387                 /* Are we in the tracing group ? */
 388                 in_tgroup = lttng_check_tracing_group();
 389         }
 390
 391         if ((uid == 0) || in_tgroup == 1) {
 392                 const int ret = lttng_strncpy(sessiond_sock_path,
 393                                 DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 394                                 sizeof(sessiond_sock_path));
 395
 396                 if (ret) {
 397                         goto error;
 398                 }
 399         }
 400
 401         if (uid != 0) {
 402                 int ret;
 403
 404                 if (in_tgroup) {
 405                         /* Tracing group. */
 406                         ret = try_connect_sessiond(sessiond_sock_path);
 407                         if (ret >= 0) {
 408                                 goto end;
 409                         }
 410                         /* Global session daemon not available... */
 411                 }
 412                 /* ...or not in tracing group (and not root), default */
 413
 414                 /*
 415                  * With GNU C <  2.1, snprintf returns -1 if the target buffer
 416                  * is too small;
 417                  * With GNU C >= 2.1, snprintf returns the required size
 418                  * (excluding closing null)
 419                  */
 420                 ret = snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
 421                                 DEFAULT_HOME_CLIENT_UNIX_SOCK, utils_get_home_dir());
 422                 if ((ret < 0) || (ret >= sizeof(sessiond_sock_path))) {
 423                         goto error;
 424                 }
 425         }
 426 end:
 427         return 0;
 428
 429 error:
 430         return -1;
 431 }
 432
 433 /*
 434  * Connect to the LTTng session daemon.
 435  *
 436  * On success, return the socket's file descriptor. On error, return -1.
 437  */
 438 LTTNG_HIDDEN int connect_sessiond(void)
 439 {
 440         int ret;
 441
 442         ret = set_session_daemon_path();
 443         if (ret < 0) {
 444                 goto error;
 445         }
 446
 447         /* Connect to the sesssion daemon. */
 448         ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 449         if (ret < 0) {
 450                 goto error;
 451         }
 452
 453         return ret;
 454
 455 error:
 456         return -1;
 457 }
 458
 459 static void reset_global_sessiond_connection_state(void)
 460 {
 461         sessiond_socket = -1;
 462         connected = 0;
 463 }
 464
 465 /*
 466  *  Clean disconnect from the session daemon.
 467  *
 468  *  On success, return 0. On error, return -1.
 469  */
 470 static int disconnect_sessiond(void)
 471 {
 472         int ret = 0;
 473
 474         if (connected) {
 475                 ret = lttcomm_close_unix_sock(sessiond_socket);
 476                 reset_global_sessiond_connection_state();
 477         }
 478
 479         return ret;
 480 }
 481
 482 static int recv_sessiond_optional_data(size_t len, void **user_buf,
 483         size_t *user_len)
 484 {
 485         int ret = 0;
 486         void *buf = NULL;
 487
 488         if (len) {
 489                 if (!user_len) {
 490                         ret = -LTTNG_ERR_INVALID;
 491                         goto end;
 492                 }
 493
 494                 buf = zmalloc(len);
 495                 if (!buf) {
 496                         ret = -ENOMEM;
 497                         goto end;
 498                 }
 499
 500                 ret = recv_data_sessiond(buf, len);
 501                 if (ret < 0) {
 502                         goto end;
 503                 }
 504
 505                 if (!user_buf) {
 506                         ret = -LTTNG_ERR_INVALID;
 507                         goto end;
 508                 }
 509
 510                 /* Move ownership of command header buffer to user. */
 511                 *user_buf = buf;
 512                 buf = NULL;
 513                 *user_len = len;
 514         } else {
 515                 /* No command header. */
 516                 if (user_len) {
 517                         *user_len = 0;
 518                 }
 519
 520                 if (user_buf) {
 521                         *user_buf = NULL;
 522                 }
 523         }
 524
 525 end:
 526         free(buf);
 527         return ret;
 528 }
 529
 530 /*
 531  * Ask the session daemon a specific command and put the data into buf.
 532  * Takes extra var. len. data and file descriptors as input to send to the
 533  * session daemon.
 534  *
 535  * Return size of data (only payload, not header) or a negative error code.
 536  */
 537 LTTNG_HIDDEN
 538 int lttng_ctl_ask_sessiond_fds_varlen(struct lttcomm_session_msg *lsm,
 539                 const int *fds, size_t nb_fd, const void *vardata,
 540                 size_t vardata_len, void **user_payload_buf,
 541                 void **user_cmd_header_buf, size_t *user_cmd_header_len)
 542 {
 543         int ret;
 544         size_t payload_len;
 545         struct lttcomm_lttng_msg llm;
 546
 547         ret = connect_sessiond();
 548         if (ret < 0) {
 549                 ret = -LTTNG_ERR_NO_SESSIOND;
 550                 goto end;
 551         } else {
 552                 sessiond_socket = ret;
 553                 connected = 1;
 554         }
 555
 556         /* Send command to session daemon */
 557         ret = send_session_msg(lsm);
 558         if (ret < 0) {
 559                 /* Ret value is a valid lttng error code. */
 560                 goto end;
 561         }
 562         /* Send var len data */
 563         ret = send_session_varlen(vardata, vardata_len);
 564         if (ret < 0) {
 565                 /* Ret value is a valid lttng error code. */
 566                 goto end;
 567         }
 568
 569         /* Send fds */
 570         ret = send_session_fds(fds, nb_fd);
 571         if (ret < 0) {
 572                 /* Ret value is a valid lttng error code. */
 573                 goto end;
 574         }
 575
 576         /* Get header from data transmission */
 577         ret = recv_data_sessiond(&llm, sizeof(llm));
 578         if (ret < 0) {
 579                 /* Ret value is a valid lttng error code. */
 580                 goto end;
 581         }
 582
 583         /* Check error code if OK */
 584         if (llm.ret_code != LTTNG_OK) {
 585                 ret = -llm.ret_code;
 586                 goto end;
 587         }
 588
 589         /* Get command header from data transmission */
 590         ret = recv_sessiond_optional_data(llm.cmd_header_size,
 591                 user_cmd_header_buf, user_cmd_header_len);
 592         if (ret < 0) {
 593                 goto end;
 594         }
 595
 596         /* Get payload from data transmission */
 597         ret = recv_sessiond_optional_data(llm.data_size, user_payload_buf,
 598                 &payload_len);
 599         if (ret < 0) {
 600                 goto end;
 601         }
 602
 603         ret = llm.data_size;
 604
 605 end:
 606         disconnect_sessiond();
 607         return ret;
 608 }
 609
 610 /*
 611  * Create lttng handle and return pointer.
 612  *
 613  * The returned pointer will be NULL in case of malloc() error.
 614  */
 615 struct lttng_handle *lttng_create_handle(const char *session_name,
 616                 struct lttng_domain *domain)
 617 {
 618         int ret;
 619         struct lttng_handle *handle = NULL;
 620
 621         handle = zmalloc(sizeof(struct lttng_handle));
 622         if (handle == NULL) {
 623                 PERROR("malloc handle");
 624                 goto end;
 625         }
 626
 627         /* Copy session name */
 628         ret = lttng_strncpy(handle->session_name, session_name ? : "",
 629                             sizeof(handle->session_name));
 630         if (ret) {
 631                 goto error;
 632         }
 633
 634         /* Copy lttng domain or leave initialized to 0. */
 635         if (domain) {
 636                 lttng_ctl_copy_lttng_domain(&handle->domain, domain);
 637         }
 638
 639 end:
 640         return handle;
 641 error:
 642         free(handle);
 643         return NULL;
 644 }
 645
 646 /*
 647  * Destroy handle by free(3) the pointer.
 648  */
 649 void lttng_destroy_handle(struct lttng_handle *handle)
 650 {
 651         free(handle);
 652 }
 653
 654 /*
 655  * Register an outside consumer.
 656  *
 657  * Returns size of returned session payload data or a negative error code.
 658  */
 659 int lttng_register_consumer(struct lttng_handle *handle,
 660                 const char *socket_path)
 661 {
 662         int ret;
 663         struct lttcomm_session_msg lsm;
 664
 665         if (handle == NULL || socket_path == NULL) {
 666                 ret = -LTTNG_ERR_INVALID;
 667                 goto end;
 668         }
 669
 670         memset(&lsm, 0, sizeof(lsm));
 671         lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
 672         ret = lttng_strncpy(lsm.session.name, handle->session_name,
 673                         sizeof(lsm.session.name));
 674         if (ret) {
 675                 ret = -LTTNG_ERR_INVALID;
 676                 goto end;
 677         }
 678
 679         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 680
 681         ret = lttng_strncpy(lsm.u.reg.path, socket_path,
 682                             sizeof(lsm.u.reg.path));
 683         if (ret) {
 684                 ret = -LTTNG_ERR_INVALID;
 685                 goto end;
 686         }
 687
 688         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 689 end:
 690         return ret;
 691 }
 692
 693 /*
 694  * Start tracing for all traces of the session.
 695  *
 696  * Returns size of returned session payload data or a negative error code.
 697  */
 698 int lttng_start_tracing(const char *session_name)
 699 {
 700         int ret;
 701         struct lttcomm_session_msg lsm;
 702
 703         if (session_name == NULL) {
 704                 ret = -LTTNG_ERR_INVALID;
 705                 goto end;
 706         }
 707
 708         memset(&lsm, 0, sizeof(lsm));
 709         lsm.cmd_type = LTTNG_START_TRACE;
 710
 711         ret = lttng_strncpy(lsm.session.name, session_name,
 712                             sizeof(lsm.session.name));
 713         if (ret) {
 714                 ret = -LTTNG_ERR_INVALID;
 715                 goto end;
 716         }
 717
 718         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 719 end:
 720         return ret;
 721 }
 722
 723 /*
 724  * Stop tracing for all traces of the session.
 725  */
 726 static int _lttng_stop_tracing(const char *session_name, int wait)
 727 {
 728         int ret, data_ret;
 729         struct lttcomm_session_msg lsm;
 730
 731         if (session_name == NULL) {
 732                 ret = -LTTNG_ERR_INVALID;
 733                 goto error;
 734         }
 735
 736         memset(&lsm, 0, sizeof(lsm));
 737         lsm.cmd_type = LTTNG_STOP_TRACE;
 738
 739         ret = lttng_strncpy(lsm.session.name, session_name,
 740                             sizeof(lsm.session.name));
 741         if (ret) {
 742                 ret = -LTTNG_ERR_INVALID;
 743                 goto error;
 744         }
 745
 746         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
 747         if (ret < 0 && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
 748                 goto error;
 749         }
 750
 751         if (!wait) {
 752                 goto end;
 753         }
 754
 755         /* Check for data availability */
 756         do {
 757                 data_ret = lttng_data_pending(session_name);
 758                 if (data_ret < 0) {
 759                         /* Return the data available call error. */
 760                         ret = data_ret;
 761                         goto error;
 762                 }
 763
 764                 /*
 765                  * Data sleep time before retrying (in usec). Don't sleep if the
 766                  * call returned value indicates availability.
 767                  */
 768                 if (data_ret) {
 769                         usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME_US);
 770                 }
 771         } while (data_ret != 0);
 772
 773 end:
 774 error:
 775         return ret;
 776 }
 777
 778 /*
 779  * Stop tracing and wait for data availability.
 780  */
 781 int lttng_stop_tracing(const char *session_name)
 782 {
 783         return _lttng_stop_tracing(session_name, 1);
 784 }
 785
 786 /*
 787  * Stop tracing but _don't_ wait for data availability.
 788  */
 789 int lttng_stop_tracing_no_wait(const char *session_name)
 790 {
 791         return _lttng_stop_tracing(session_name, 0);
 792 }
 793
 794 /*
 795  * Add context to a channel.
 796  *
 797  * If the given channel is NULL, add the contexts to all channels.
 798  * The event_name param is ignored.
 799  *
 800  * Returns the size of the returned payload data or a negative error code.
 801  */
 802 int lttng_add_context(struct lttng_handle *handle,
 803                 struct lttng_event_context *ctx, const char *event_name,
 804                 const char *channel_name)
 805 {
 806         int ret;
 807         struct lttcomm_session_msg lsm;
 808         struct lttng_dynamic_buffer buffer;
 809
 810         lttng_dynamic_buffer_init(&buffer);
 811
 812         /* Safety check. Both are mandatory. */
 813         if (handle == NULL || ctx == NULL) {
 814                 ret = -LTTNG_ERR_INVALID;
 815                 goto end;
 816         }
 817
 818         memset(&lsm, 0, sizeof(lsm));
 819         lsm.cmd_type = LTTNG_ADD_CONTEXT;
 820
 821         /* If no channel name, send empty string. */
 822         ret = lttng_strncpy(lsm.u.context.channel_name, channel_name ?: "",
 823                         sizeof(lsm.u.context.channel_name));
 824         if (ret) {
 825                 ret = -LTTNG_ERR_INVALID;
 826                 goto end;
 827         }
 828
 829         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
 830         ret = lttng_strncpy(lsm.session.name, handle->session_name,
 831                         sizeof(lsm.session.name));
 832         if (ret) {
 833                 ret = -LTTNG_ERR_INVALID;
 834                 goto end;
 835         }
 836
 837         ret = lttng_event_context_serialize(ctx, &buffer);
 838         if (ret) {
 839                 ret = -LTTNG_ERR_INVALID;
 840                 goto end;
 841         }
 842
 843         lsm.u.context.length = buffer.size;
 844
 845         ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(
 846                         &lsm, buffer.data, buffer.size, NULL);
 847 end:
 848         lttng_dynamic_buffer_reset(&buffer);
 849         return ret;
 850 }
 851
 852 /*
 853  * Enable event(s) for a channel.
 854  *
 855  * If no event name is specified, all events are enabled.
 856  * If no channel name is specified, the default 'channel0' is used.
 857  *
 858  * Returns size of returned session payload data or a negative error code.
 859  */
 860 int lttng_enable_event(struct lttng_handle *handle,
 861                 struct lttng_event *ev, const char *channel_name)
 862 {
 863         return lttng_enable_event_with_exclusions(handle, ev, channel_name,
 864                         NULL, 0, NULL);
 865 }
 866
 867 /*
 868  * Create or enable an event with a filter expression.
 869  *
 870  * Return negative error value on error.
 871  * Return size of returned session payload data if OK.
 872  */
 873 int lttng_enable_event_with_filter(struct lttng_handle *handle,
 874                 struct lttng_event *event, const char *channel_name,
 875                 const char *filter_expression)
 876 {
 877         return lttng_enable_event_with_exclusions(handle, event, channel_name,
 878                         filter_expression, 0, NULL);
 879 }
 880
 881 /*
 882  * Depending on the event, return a newly allocated agent filter expression or
 883  * NULL if not applicable.
 884  *
 885  * An event with NO loglevel and the name is * will return NULL.
 886  */
 887 static char *set_agent_filter(const char *filter, struct lttng_event *ev)
 888 {
 889         int err;
 890         char *agent_filter = NULL;
 891
 892         assert(ev);
 893
 894         /* Don't add filter for the '*' event. */
 895         if (strcmp(ev->name, "*") != 0) {
 896                 if (filter) {
 897                         err = asprintf(&agent_filter, "(%s) && (logger_name == \"%s\")", filter,
 898                                         ev->name);
 899                 } else {
 900                         err = asprintf(&agent_filter, "logger_name == \"%s\"", ev->name);
 901                 }
 902                 if (err < 0) {
 903                         PERROR("asprintf");
 904                         goto error;
 905                 }
 906         }
 907
 908         /* Add loglevel filtering if any for the JUL domain. */
 909         if (ev->loglevel_type != LTTNG_EVENT_LOGLEVEL_ALL) {
 910                 const char *op;
 911
 912                 if (ev->loglevel_type == LTTNG_EVENT_LOGLEVEL_RANGE) {
 913                         op = ">=";
 914                 } else {
 915                         op = "==";
 916                 }
 917
 918                 if (filter || agent_filter) {
 919                         char *new_filter;
 920
 921                         err = asprintf(&new_filter, "(%s) && (int_loglevel %s %d)",
 922                                         agent_filter ? agent_filter : filter, op,
 923                                         ev->loglevel);
 924                         if (agent_filter) {
 925                                 free(agent_filter);
 926                         }
 927                         agent_filter = new_filter;
 928                 } else {
 929                         err = asprintf(&agent_filter, "int_loglevel %s %d", op,
 930                                         ev->loglevel);
 931                 }
 932                 if (err < 0) {
 933                         PERROR("asprintf");
 934                         goto error;
 935                 }
 936         }
 937
 938         return agent_filter;
 939 error:
 940         free(agent_filter);
 941         return NULL;
 942 }
 943
 944 /*
 945  * Generate the filter bytecode from a given filter expression string. Put the
 946  * newly allocated parser context in ctxp and populate the lsm object with the
 947  * expression len.
 948  *
 949  * Return 0 on success else a LTTNG_ERR_* code and ctxp is untouched.
 950  */
 951 static int generate_filter(char *filter_expression,
 952                 size_t *bytecode_len,
 953                 struct filter_parser_ctx **ctxp)
 954 {
 955         int ret;
 956         struct filter_parser_ctx *ctx = NULL;
 957         FILE *fmem = NULL;
 958
 959         assert(filter_expression);
 960         assert(ctxp);
 961
 962         /*
 963          * Casting const to non-const, as the underlying function will use it in
 964          * read-only mode.
 965          */
 966         fmem = lttng_fmemopen((void *) filter_expression,
 967                         strlen(filter_expression), "r");
 968         if (!fmem) {
 969                 fprintf(stderr, "Error opening memory as stream\n");
 970                 ret = -LTTNG_ERR_FILTER_NOMEM;
 971                 goto error;
 972         }
 973         ctx = filter_parser_ctx_alloc(fmem);
 974         if (!ctx) {
 975                 fprintf(stderr, "Error allocating parser\n");
 976                 ret = -LTTNG_ERR_FILTER_NOMEM;
 977                 goto filter_alloc_error;
 978         }
 979         ret = filter_parser_ctx_append_ast(ctx);
 980         if (ret) {
 981                 fprintf(stderr, "Parse error\n");
 982                 ret = -LTTNG_ERR_FILTER_INVAL;
 983                 goto parse_error;
 984         }
 985         if (print_xml) {
 986                 ret = filter_visitor_print_xml(ctx, stdout, 0);
 987                 if (ret) {
 988                         fflush(stdout);
 989                         fprintf(stderr, "XML print error\n");
 990                         ret = -LTTNG_ERR_FILTER_INVAL;
 991                         goto parse_error;
 992                 }
 993         }
 994
 995         dbg_printf("Generating IR... ");
 996         fflush(stdout);
 997         ret = filter_visitor_ir_generate(ctx);
 998         if (ret) {
 999                 fprintf(stderr, "Generate IR error\n");
1000                 ret = -LTTNG_ERR_FILTER_INVAL;
1001                 goto parse_error;
1002         }
1003         dbg_printf("done\n");
1004
1005         dbg_printf("Validating IR... ");
1006         fflush(stdout);
1007         ret = filter_visitor_ir_check_binary_op_nesting(ctx);
1008         if (ret) {
1009                 ret = -LTTNG_ERR_FILTER_INVAL;
1010                 goto parse_error;
1011         }
1012
1013         /* Normalize globbing patterns in the expression. */
1014         ret = filter_visitor_ir_normalize_glob_patterns(ctx);
1015         if (ret) {
1016                 ret = -LTTNG_ERR_FILTER_INVAL;
1017                 goto parse_error;
1018         }
1019
1020         /* Validate strings used as literals in the expression. */
1021         ret = filter_visitor_ir_validate_string(ctx);
1022         if (ret) {
1023                 ret = -LTTNG_ERR_FILTER_INVAL;
1024                 goto parse_error;
1025         }
1026
1027         /* Validate globbing patterns in the expression. */
1028         ret = filter_visitor_ir_validate_globbing(ctx);
1029         if (ret) {
1030                 ret = -LTTNG_ERR_FILTER_INVAL;
1031                 goto parse_error;
1032         }
1033
1034         dbg_printf("done\n");
1035
1036         dbg_printf("Generating bytecode... ");
1037         fflush(stdout);
1038         ret = filter_visitor_bytecode_generate(ctx);
1039         if (ret) {
1040                 fprintf(stderr, "Generate bytecode error\n");
1041                 ret = -LTTNG_ERR_FILTER_INVAL;
1042                 goto parse_error;
1043         }
1044         dbg_printf("done\n");
1045         dbg_printf("Size of bytecode generated: %u bytes.\n",
1046                         bytecode_get_len(&ctx->bytecode->b));
1047
1048         *bytecode_len = sizeof(ctx->bytecode->b) +
1049                         bytecode_get_len(&ctx->bytecode->b);
1050
1051         /* No need to keep the memory stream. */
1052         if (fclose(fmem) != 0) {
1053                 PERROR("fclose");
1054         }
1055
1056         *ctxp = ctx;
1057         return 0;
1058
1059 parse_error:
1060         filter_ir_free(ctx);
1061         filter_parser_ctx_free(ctx);
1062 filter_alloc_error:
1063         if (fclose(fmem) != 0) {
1064                 PERROR("fclose");
1065         }
1066 error:
1067         return ret;
1068 }
1069
1070 /*
1071  * Enable event(s) for a channel, possibly with exclusions and a filter.
1072  * If no event name is specified, all events are enabled.
1073  * If no channel name is specified, the default name is used.
1074  * If filter expression is not NULL, the filter is set for the event.
1075  * If exclusion count is not zero, the exclusions are set for the event.
1076  * Returns size of returned session payload data or a negative error code.
1077  */
1078 int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
1079                 struct lttng_event *ev, const char *channel_name,
1080                 const char *original_filter_expression,
1081                 int exclusion_count, char **exclusion_list)
1082 {
1083         struct lttcomm_session_msg lsm;
1084         struct lttng_dynamic_buffer send_buffer;
1085         int ret = 0, fd_to_send = -1;
1086         bool send_fd = false;
1087         unsigned int free_filter_expression = 0;
1088         struct filter_parser_ctx *ctx = NULL;
1089         size_t bytecode_len = 0;
1090
1091         /*
1092          * We have either a filter or some exclusions, so we need to set up
1093          * a variable-length memory block from where to send the data.
1094          */
1095         lttng_dynamic_buffer_init(&send_buffer);
1096
1097         /*
1098          * Cast as non-const since we may replace the filter expression
1099          * by a dynamically allocated string. Otherwise, the original
1100          * string is not modified.
1101          */
1102         char *filter_expression = (char *) original_filter_expression;
1103
1104         if (handle == NULL || ev == NULL) {
1105                 ret = -LTTNG_ERR_INVALID;
1106                 goto error;
1107         }
1108
1109         /*
1110          * Empty filter string will always be rejected by the parser
1111          * anyway, so treat this corner-case early to eliminate
1112          * lttng_fmemopen error for 0-byte allocation.
1113          */
1114         if (filter_expression && filter_expression[0] == '\0') {
1115                 ret = -LTTNG_ERR_INVALID;
1116                 goto error;
1117         }
1118
1119         if (ev->name[0] == '\0') {
1120                 /* Enable all events. */
1121                 ret = lttng_strncpy(ev->name, "*", sizeof(ev->name));
1122                 assert(ret == 0);
1123         }
1124
1125         /* Parse filter expression. */
1126         if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
1127                         || handle->domain.type == LTTNG_DOMAIN_LOG4J
1128                         || handle->domain.type == LTTNG_DOMAIN_PYTHON) {
1129                 if (handle->domain.type == LTTNG_DOMAIN_JUL ||
1130                                 handle->domain.type == LTTNG_DOMAIN_LOG4J ||
1131                                 handle->domain.type == LTTNG_DOMAIN_PYTHON) {
1132                         char *agent_filter;
1133
1134                         /* Setup agent filter if needed. */
1135                         agent_filter = set_agent_filter(filter_expression, ev);
1136                         if (!agent_filter) {
1137                                 if (!filter_expression) {
1138                                         /*
1139                                          * No JUL and no filter, just skip
1140                                          * everything below.
1141                                          */
1142                                         goto serialize;
1143                                 }
1144                         } else {
1145                                 /*
1146                                  * With an agent filter, the original filter has
1147                                  * been added to it thus replace the filter
1148                                  * expression.
1149                                  */
1150                                 filter_expression = agent_filter;
1151                                 free_filter_expression = 1;
1152                         }
1153                 }
1154
1155                 if (strnlen(filter_expression, LTTNG_FILTER_MAX_LEN) ==
1156                                 LTTNG_FILTER_MAX_LEN) {
1157                         ret = -LTTNG_ERR_FILTER_INVAL;
1158                         goto error;
1159                 }
1160
1161                 ret = generate_filter(filter_expression, &bytecode_len, &ctx);
1162                 if (ret) {
1163                         goto error;
1164                 }
1165
1166                 if (bytecode_len > LTTNG_FILTER_MAX_LEN) {
1167                         ret = -LTTNG_ERR_FILTER_INVAL;
1168                         goto error;
1169                 }
1170         }
1171
1172 serialize:
1173         ret = lttng_event_serialize(ev, exclusion_count, exclusion_list,
1174                         filter_expression, bytecode_len,
1175                         ctx && (bytecode_len != 0) ? &ctx->bytecode->b : NULL,
1176                         &send_buffer, &fd_to_send);
1177         if (ret) {
1178                 goto error;
1179         }
1180
1181         if (fd_to_send >= 0) {
1182                 send_fd = true;
1183         }
1184
1185         /* Prepare the command header */
1186         memset(&lsm, 0, sizeof(lsm));
1187         lsm.cmd_type = LTTNG_ENABLE_EVENT;
1188
1189         /* If no channel name, send empty string. */
1190         ret = lttng_strncpy(lsm.u.enable.channel_name, channel_name ?: "",
1191                         sizeof(lsm.u.enable.channel_name));
1192         if (ret) {
1193                 ret = -LTTNG_ERR_INVALID;
1194                 goto error;
1195         }
1196
1197         /* Domain */
1198         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
1199
1200         /* Session name */
1201         ret = lttng_strncpy(lsm.session.name, handle->session_name,
1202                         sizeof(lsm.session.name));
1203         if (ret) {
1204                 ret = -LTTNG_ERR_INVALID;
1205                 goto error;
1206         }
1207
1208         /* Length of the serialized event */
1209         lsm.u.enable.length = (uint32_t) send_buffer.size;
1210
1211         ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm,
1212                         send_fd ? &fd_to_send : NULL,
1213                         send_fd ? 1 : 0,
1214                         send_buffer.size ? send_buffer.data : NULL,
1215                         send_buffer.size, NULL, NULL, 0);
1216 error:
1217         if (filter_expression && ctx) {
1218                 filter_bytecode_free(ctx);
1219                 filter_ir_free(ctx);
1220                 filter_parser_ctx_free(ctx);
1221         }
1222
1223         if (free_filter_expression) {
1224                 /*
1225                  * The filter expression has been replaced and must be freed as
1226                  * it is not the original filter expression received as a
1227                  * parameter.
1228                  */
1229                 free(filter_expression);
1230         }
1231
1232         lttng_dynamic_buffer_reset(&send_buffer);
1233         return ret;
1234 }
1235
1236 int lttng_disable_event_ext(struct lttng_handle *handle,
1237                 struct lttng_event *ev, const char *channel_name,
1238                 const char *original_filter_expression)
1239 {
1240         struct lttcomm_session_msg lsm;
1241         struct lttng_dynamic_buffer buf;
1242         int ret = 0;
1243         unsigned int free_filter_expression = 0;
1244         struct filter_parser_ctx *ctx = NULL;
1245         size_t bytecode_len = 0;
1246         int fd_to_send = -1;
1247         bool send_fd = false;
1248         /*
1249          * Cast as non-const since we may replace the filter expression
1250          * by a dynamically allocated string. Otherwise, the original
1251          * string is not modified.
1252          */
1253         char *filter_expression = (char *) original_filter_expression;
1254
1255         lttng_dynamic_buffer_init(&buf);
1256
1257         if (handle == NULL || ev == NULL) {
1258                 ret = -LTTNG_ERR_INVALID;
1259                 goto error;
1260         }
1261
1262         /*
1263          * Empty filter string will always be rejected by the parser
1264          * anyway, so treat this corner-case early to eliminate
1265          * lttng_fmemopen error for 0-byte allocation.
1266          */
1267         if (filter_expression && filter_expression[0] == '\0') {
1268                 ret = -LTTNG_ERR_INVALID;
1269                 goto error;
1270         }
1271
1272         /* Parse filter expression */
1273         if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
1274                         || handle->domain.type == LTTNG_DOMAIN_LOG4J
1275                         || handle->domain.type == LTTNG_DOMAIN_PYTHON) {
1276                 if (handle->domain.type == LTTNG_DOMAIN_JUL ||
1277                                 handle->domain.type == LTTNG_DOMAIN_LOG4J ||
1278                                 handle->domain.type == LTTNG_DOMAIN_PYTHON) {
1279                         char *agent_filter;
1280
1281                         /* Setup agent filter if needed. */
1282                         agent_filter = set_agent_filter(filter_expression, ev);
1283                         if (!agent_filter) {
1284                                 if (!filter_expression) {
1285                                         /*
1286                                          * No JUL and no filter, just skip
1287                                          * everything below.
1288                                          */
1289                                         goto serialize;
1290                                 }
1291                         } else {
1292                                 /*
1293                                  * With a JUL filter, the original filter has
1294                                  * been added to it thus replace the filter
1295                                  * expression.
1296                                  */
1297                                 filter_expression = agent_filter;
1298                                 free_filter_expression = 1;
1299                         }
1300                 }
1301
1302                 ret = generate_filter(filter_expression, &bytecode_len, &ctx);
1303                 if (ret) {
1304                         ret = -1;
1305                         goto error;
1306                 }
1307         }
1308
1309 serialize:
1310         ret = lttng_event_serialize(ev, 0, NULL, filter_expression,
1311                         bytecode_len,
1312                         ctx && (bytecode_len != 0) ? &ctx->bytecode->b : NULL,
1313                         &buf, &fd_to_send);
1314         if (ret) {
1315                 ret = -1;
1316                 goto error;
1317         }
1318
1319         if (fd_to_send >= 0) {
1320                 send_fd = true;
1321         }
1322
1323         /* Prepare command header */
1324         memset(&lsm, 0, sizeof(lsm));
1325         lsm.cmd_type = LTTNG_DISABLE_EVENT;
1326
1327         /* If no channel name, send empty string. */
1328         ret = lttng_strncpy(lsm.u.disable.channel_name, channel_name ?: "",
1329                         sizeof(lsm.u.disable.channel_name));
1330         if (ret) {
1331                 ret = -LTTNG_ERR_INVALID;
1332                 goto error;
1333         }
1334         /* Domain */
1335         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
1336
1337         /* Session name */
1338         ret = lttng_strncpy(lsm.session.name, handle->session_name,
1339                         sizeof(lsm.session.name));
1340         if (ret) {
1341                 ret = -LTTNG_ERR_INVALID;
1342                 goto error;
1343         }
1344
1345         /* Length of the serialized event */
1346         lsm.u.disable.length = (uint32_t) buf.size;
1347
1348         ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm,
1349                         send_fd ? &fd_to_send : NULL, send_fd ? 1 : 0,
1350                         buf.size ? buf.data : NULL, buf.size, NULL, NULL, 0);
1351
1352 error:
1353         if (filter_expression && ctx) {
1354                 filter_bytecode_free(ctx);
1355                 filter_ir_free(ctx);
1356                 filter_parser_ctx_free(ctx);
1357         }
1358
1359         if (free_filter_expression) {
1360                 /*
1361                  * The filter expression has been replaced and must be freed as
1362                  * it is not the original filter expression received as a
1363                  * parameter.
1364                  */
1365                 free(filter_expression);
1366         }
1367
1368         lttng_dynamic_buffer_reset(&buf);
1369         return ret;
1370 }
1371
1372 /*
1373  * Disable event(s) of a channel and domain.
1374  * If no event name is specified, all events are disabled.
1375  * If no channel name is specified, the default 'channel0' is used.
1376  * Returns size of returned session payload data or a negative error code.
1377  */
1378 int lttng_disable_event(struct lttng_handle *handle, const char *name,
1379                 const char *channel_name)
1380 {
1381         int ret;
1382         struct lttng_event ev;
1383
1384         memset(&ev, 0, sizeof(ev));
1385         ev.loglevel = -1;
1386         ev.type = LTTNG_EVENT_ALL;
1387         ret = lttng_strncpy(ev.name, name ?: "", sizeof(ev.name));
1388         if (ret) {
1389                 ret = -LTTNG_ERR_INVALID;
1390                 goto end;
1391         }
1392
1393         ret = lttng_disable_event_ext(handle, &ev, channel_name, NULL);
1394 end:
1395         return ret;
1396 }
1397
1398 struct lttng_channel *lttng_channel_create(struct lttng_domain *domain)
1399 {
1400         struct lttng_channel *channel = NULL;
1401
1402         if (!domain) {
1403                 goto end;
1404         }
1405
1406         /* Validate domain. */
1407         switch (domain->type) {
1408         case LTTNG_DOMAIN_UST:
1409                 switch (domain->buf_type) {
1410                 case LTTNG_BUFFER_PER_UID:
1411                 case LTTNG_BUFFER_PER_PID:
1412                         break;
1413                 default:
1414                         goto end;
1415                 }
1416                 break;
1417         case LTTNG_DOMAIN_KERNEL:
1418                 if (domain->buf_type != LTTNG_BUFFER_GLOBAL) {
1419                         goto end;
1420                 }
1421                 break;
1422         default:
1423                 goto end;
1424         }
1425
1426         channel = lttng_channel_create_internal();
1427         if (!channel) {
1428                 goto end;
1429         }
1430
1431         lttng_channel_set_default_attr(domain, &channel->attr);
1432 end:
1433         return channel;
1434 }
1435
1436 void lttng_channel_destroy(struct lttng_channel *channel)
1437 {
1438         if (!channel) {
1439                 return;
1440         }
1441
1442         if (channel->attr.extended.ptr) {
1443                 free(channel->attr.extended.ptr);
1444         }
1445         free(channel);
1446 }
1447
1448 /*
1449  * Enable channel per domain
1450  * Returns size of returned session payload data or a negative error code.
1451  */
1452 int lttng_enable_channel(struct lttng_handle *handle,
1453                 struct lttng_channel *in_chan)
1454 {
1455         enum lttng_error_code ret_code;
1456         int ret;
1457         struct lttng_dynamic_buffer buffer;
1458         struct lttcomm_session_msg lsm;
1459         uint64_t total_buffer_size_needed_per_cpu = 0;
1460         struct lttng_channel *channel = NULL;
1461
1462         lttng_dynamic_buffer_init(&buffer);
1463
1464         /* NULL arguments are forbidden. No default values. */
1465         if (handle == NULL || in_chan == NULL) {
1466                 ret = -LTTNG_ERR_INVALID;
1467                 goto end;
1468         }
1469
1470         /*
1471          * Verify that the amount of memory required to create the requested
1472          * buffer is available on the system at the moment.
1473          */
1474         if (in_chan->attr.num_subbuf >
1475                         UINT64_MAX / in_chan->attr.subbuf_size) {
1476                 /* Overflow */
1477                 ret = -LTTNG_ERR_OVERFLOW;
1478                 goto end;
1479         }
1480
1481         total_buffer_size_needed_per_cpu =
1482                         in_chan->attr.num_subbuf * in_chan->attr.subbuf_size;
1483         ret_code = check_enough_available_memory(
1484                         total_buffer_size_needed_per_cpu);
1485         if (ret_code != LTTNG_OK) {
1486                 ret = -ret_code;
1487                 goto end;
1488         }
1489
1490         /* Copy the channel for easier manipulation. */
1491         channel = lttng_channel_copy(in_chan);
1492         if (!channel) {
1493                 ret = -LTTNG_ERR_NOMEM;
1494                 goto end;
1495         }
1496
1497         /* Populate the channel extended attribute if necessary. */
1498         if (!channel->attr.extended.ptr) {
1499                 struct lttng_channel_extended *extended =
1500                                 zmalloc(sizeof(*extended));
1501
1502                 if (!extended) {
1503                         ret = -LTTNG_ERR_NOMEM;
1504                         goto end;
1505                 }
1506                 lttng_channel_set_default_extended_attr(
1507                                 &handle->domain, extended);
1508                 channel->attr.extended.ptr = extended;
1509         }
1510
1511         /* Prepare the payload */
1512         memset(&lsm, 0, sizeof(lsm));
1513
1514         lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
1515         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
1516
1517         ret = lttng_strncpy(lsm.session.name, handle->session_name,
1518                                     sizeof(lsm.session.name));
1519         if (ret) {
1520                 ret = -LTTNG_ERR_INVALID;
1521                 goto end;
1522         }
1523
1524         ret = lttng_channel_serialize(channel, &buffer);
1525         if (ret) {
1526                 ret = -LTTNG_ERR_FATAL;
1527                 goto end;
1528         }
1529
1530         lsm.u.channel.length = buffer.size;
1531
1532         ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(
1533                         &lsm, buffer.data, buffer.size, NULL);
1534 end:
1535         lttng_channel_destroy(channel);
1536         lttng_dynamic_buffer_reset(&buffer);
1537         return ret;
1538 }
1539
1540 /*
1541  * All tracing will be stopped for registered events of the channel.
1542  * Returns size of returned session payload data or a negative error code.
1543  */
1544 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
1545 {
1546         int ret;
1547         struct lttcomm_session_msg lsm;
1548
1549         /* Safety check. Both are mandatory. */
1550         if (handle == NULL || name == NULL) {
1551                 return -LTTNG_ERR_INVALID;
1552         }
1553
1554         memset(&lsm, 0, sizeof(lsm));
1555
1556         lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
1557
1558         ret = lttng_strncpy(lsm.u.disable.channel_name, name,
1559                         sizeof(lsm.u.disable.channel_name));
1560         if (ret) {
1561                 ret = -LTTNG_ERR_INVALID;
1562                 goto end;
1563         }
1564
1565         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
1566
1567         ret = lttng_strncpy(lsm.session.name, handle->session_name,
1568                             sizeof(lsm.session.name));
1569         if (ret) {
1570                 ret = -LTTNG_ERR_INVALID;
1571                 goto end;
1572         }
1573
1574         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
1575 end:
1576         return ret;
1577 }
1578
1579 /*
1580  * Lists all available tracepoints of domain.
1581  * Sets the contents of the events array.
1582  * Returns the number of lttng_event entries in events;
1583  * on error, returns a negative value.
1584  */
1585 int lttng_list_tracepoints(struct lttng_handle *handle,
1586                 struct lttng_event **events)
1587 {
1588         enum lttng_error_code ret_code;
1589         int ret, total_payload_received;
1590         char *reception_buffer = NULL;
1591         struct lttcomm_session_msg lsm;
1592         struct lttcomm_list_command_header *cmd_header = NULL;
1593         size_t cmd_header_len;
1594         unsigned int nb_events = 0;
1595
1596         if (handle == NULL) {
1597                 ret = -LTTNG_ERR_INVALID;
1598                 goto end;
1599         }
1600
1601         memset(&lsm, 0, sizeof(lsm));
1602         lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
1603         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
1604
1605         ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
1606                         (void **) &reception_buffer, (void **) &cmd_header,
1607                         &cmd_header_len);
1608         if (ret < 0) {
1609                 goto end;
1610         }
1611         total_payload_received = ret;
1612
1613         if (!cmd_header) {
1614                 ret = -LTTNG_ERR_UNK;
1615                 goto end;
1616         }
1617
1618         if (cmd_header->count > INT_MAX) {
1619                 ret = -LTTNG_ERR_OVERFLOW;
1620                 goto end;
1621         }
1622
1623         nb_events = (unsigned int) cmd_header->count;
1624
1625         {
1626                 const struct lttng_buffer_view events_view =
1627                                 lttng_buffer_view_init(reception_buffer, 0,
1628                                                 total_payload_received);
1629
1630                 ret_code = lttng_events_create_and_flatten_from_buffer(
1631                                 &events_view, nb_events, events);
1632                 if (ret_code != LTTNG_OK) {
1633                         ret = -ret_code;
1634                         goto end;
1635                 }
1636         }
1637
1638         ret = (int) nb_events;
1639
1640 end:
1641         free(cmd_header);
1642         free(reception_buffer);
1643         return ret;
1644 }
1645
1646 /*
1647  * Lists all available tracepoint fields of domain.
1648  * Sets the contents of the event field array.
1649  * Returns the number of lttng_event_field entries in events;
1650  * on error, returns a negative value.
1651  */
1652 int lttng_list_tracepoint_fields(struct lttng_handle *handle,
1653                 struct lttng_event_field **fields)
1654 {
1655         int ret;
1656         struct lttcomm_session_msg lsm;
1657
1658         if (handle == NULL) {
1659                 return -LTTNG_ERR_INVALID;
1660         }
1661
1662         memset(&lsm, 0, sizeof(lsm));
1663         lsm.cmd_type = LTTNG_LIST_TRACEPOINT_FIELDS;
1664         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
1665
1666         ret = lttng_ctl_ask_sessiond(&lsm, (void **) fields);
1667         if (ret < 0) {
1668                 return ret;
1669         }
1670
1671         return ret / sizeof(struct lttng_event_field);
1672 }
1673
1674 /*
1675  * Lists all available kernel system calls. Allocates and sets the contents of
1676  * the events array.
1677  *
1678  * Returns the number of lttng_event entries in events; on error, returns a
1679  * negative value.
1680  */
1681 int lttng_list_syscalls(struct lttng_event **events)
1682 {
1683         enum lttng_error_code ret_code;
1684         int ret, total_payload_received;
1685         char *reception_buffer = NULL;
1686         struct lttcomm_session_msg lsm;
1687         struct lttcomm_list_command_header *cmd_header = NULL;
1688         size_t cmd_header_len;
1689         uint32_t nb_events = 0;
1690
1691         if (!events) {
1692                 ret = -LTTNG_ERR_INVALID;
1693                 goto end;
1694         }
1695
1696         memset(&lsm, 0, sizeof(lsm));
1697         lsm.cmd_type = LTTNG_LIST_SYSCALLS;
1698         /* Force kernel domain for system calls. */
1699         lsm.domain.type = LTTNG_DOMAIN_KERNEL;
1700
1701         ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
1702                         (void **) &reception_buffer, (void **) &cmd_header,
1703                         &cmd_header_len);
1704         if (ret < 0) {
1705                 goto end;
1706         }
1707         total_payload_received = ret;
1708
1709         if (!cmd_header) {
1710                 ret = -LTTNG_ERR_UNK;
1711                 goto end;
1712         }
1713
1714         if (cmd_header->count > INT_MAX) {
1715                 ret = -LTTNG_ERR_OVERFLOW;
1716                 goto end;
1717         }
1718
1719         nb_events = (unsigned int) cmd_header->count;
1720
1721         {
1722                 const struct lttng_buffer_view events_view =
1723                                 lttng_buffer_view_init(reception_buffer, 0,
1724                                                 total_payload_received);
1725
1726                 ret_code = lttng_events_create_and_flatten_from_buffer(
1727                                 &events_view, nb_events, events);
1728                 if (ret_code != LTTNG_OK) {
1729                         ret = -ret_code;
1730                         goto end;
1731                 }
1732         }
1733
1734         ret = (int) nb_events;
1735
1736 end:
1737         free(reception_buffer);
1738         free(cmd_header);
1739         return ret;
1740 }
1741
1742 /*
1743  * Returns a human readable string describing
1744  * the error code (a negative value).
1745  */
1746 const char *lttng_strerror(int code)
1747 {
1748         return error_get_str(code);
1749 }
1750
1751 enum lttng_error_code lttng_create_session_ext(
1752                 struct lttng_session_descriptor *session_descriptor)
1753 {
1754         enum lttng_error_code ret_code;
1755         struct lttcomm_session_msg lsm = {
1756                 .cmd_type = LTTNG_CREATE_SESSION_EXT,
1757         };
1758         void *reply = NULL;
1759         struct lttng_buffer_view reply_view;
1760         int reply_ret;
1761         bool sessiond_must_generate_ouput;
1762         struct lttng_dynamic_buffer payload;
1763         int ret;
1764         size_t descriptor_size;
1765         struct lttng_session_descriptor *descriptor_reply = NULL;
1766
1767         lttng_dynamic_buffer_init(&payload);
1768         if (!session_descriptor) {
1769                 ret_code = LTTNG_ERR_INVALID;
1770                 goto end;
1771         }
1772
1773         sessiond_must_generate_ouput =
1774                         !lttng_session_descriptor_is_output_destination_initialized(
1775                                 session_descriptor);
1776         if (sessiond_must_generate_ouput) {
1777                 const char *home_dir = utils_get_home_dir();
1778                 size_t home_dir_len = home_dir ? strlen(home_dir) + 1 : 0;
1779
1780                 if (!home_dir || home_dir_len > LTTNG_PATH_MAX) {
1781                         ret_code = LTTNG_ERR_FATAL;
1782                         goto end;
1783                 }
1784
1785                 lsm.u.create_session.home_dir_size = (uint16_t) home_dir_len;
1786                 ret = lttng_dynamic_buffer_append(&payload, home_dir,
1787                                 home_dir_len);
1788                 if (ret) {
1789                         ret_code = LTTNG_ERR_NOMEM;
1790                         goto end;
1791                 }
1792         }
1793
1794         descriptor_size = payload.size;
1795         ret = lttng_session_descriptor_serialize(session_descriptor,
1796                         &payload);
1797         if (ret) {
1798                 ret_code = LTTNG_ERR_INVALID;
1799                 goto end;
1800         }
1801         descriptor_size = payload.size - descriptor_size;
1802         lsm.u.create_session.session_descriptor_size = descriptor_size;
1803
1804         /* Command returns a session descriptor on success. */
1805         reply_ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, payload.data,
1806                         payload.size, &reply);
1807         if (reply_ret < 0) {
1808                 ret_code = -reply_ret;
1809                 goto end;
1810         } else if (reply_ret == 0) {
1811                 /* Socket unexpectedly closed by the session daemon. */
1812                 ret_code = LTTNG_ERR_FATAL;
1813                 goto end;
1814         }
1815
1816         reply_view = lttng_buffer_view_init(reply, 0, reply_ret);
1817         ret = lttng_session_descriptor_create_from_buffer(&reply_view,
1818                         &descriptor_reply);
1819         if (ret < 0) {
1820                 ret_code = LTTNG_ERR_FATAL;
1821                 goto end;
1822         }
1823         ret_code = LTTNG_OK;
1824         lttng_session_descriptor_assign(session_descriptor, descriptor_reply);
1825 end:
1826         free(reply);
1827         lttng_dynamic_buffer_reset(&payload);
1828         lttng_session_descriptor_destroy(descriptor_reply);
1829         return ret_code;
1830 }
1831
1832 /*
1833  * Create a new session using name and url for destination.
1834  *
1835  * Return 0 on success else a negative LTTng error code.
1836  */
1837 int lttng_create_session(const char *name, const char *url)
1838 {
1839         int ret;
1840         ssize_t size;
1841         struct lttng_uri *uris = NULL;
1842         struct lttng_session_descriptor *descriptor = NULL;
1843         enum lttng_error_code ret_code;
1844
1845         if (!name) {
1846                 ret = -LTTNG_ERR_INVALID;
1847                 goto end;
1848         }
1849
1850         size = uri_parse_str_urls(url, NULL, &uris);
1851         if (size < 0) {
1852                 ret = -LTTNG_ERR_INVALID;
1853                 goto end;
1854         }
1855         switch (size) {
1856         case 0:
1857                 descriptor = lttng_session_descriptor_create(name);
1858                 break;
1859         case 1:
1860                 if (uris[0].dtype != LTTNG_DST_PATH) {
1861                         ret = -LTTNG_ERR_INVALID;
1862                         goto end;
1863                 }
1864                 descriptor = lttng_session_descriptor_local_create(name,
1865                                 uris[0].dst.path);
1866                 break;
1867         case 2:
1868                 descriptor = lttng_session_descriptor_network_create(name, url,
1869                                 NULL);
1870                 break;
1871         default:
1872                 ret = -LTTNG_ERR_INVALID;
1873                 goto end;
1874         }
1875         if (!descriptor) {
1876                 ret = -LTTNG_ERR_INVALID;
1877                 goto end;
1878         }
1879         ret_code = lttng_create_session_ext(descriptor);
1880         ret = ret_code == LTTNG_OK ? 0 : -ret_code;
1881 end:
1882         lttng_session_descriptor_destroy(descriptor);
1883         free(uris);
1884         return ret;
1885 }
1886
1887 /*
1888  * Create a session exclusively used for snapshot.
1889  *
1890  * Return 0 on success else a negative LTTng error code.
1891  */
1892 int lttng_create_session_snapshot(const char *name, const char *snapshot_url)
1893 {
1894         int ret;
1895         enum lttng_error_code ret_code;
1896         ssize_t size;
1897         struct lttng_uri *uris = NULL;
1898         struct lttng_session_descriptor *descriptor = NULL;
1899
1900         if (!name) {
1901                 ret = -LTTNG_ERR_INVALID;
1902                 goto end;
1903         }
1904
1905         size = uri_parse_str_urls(snapshot_url, NULL, &uris);
1906         if (size < 0) {
1907                 ret = -LTTNG_ERR_INVALID;
1908                 goto end;
1909         }
1910         /*
1911          * If the user does not specify a custom subdir, use the session name.
1912          */
1913         if (size > 0 && uris[0].dtype != LTTNG_DST_PATH &&
1914                         strlen(uris[0].subdir) == 0) {
1915                 ret = snprintf(uris[0].subdir, sizeof(uris[0].subdir), "%s",
1916                                 name);
1917                 if (ret < 0) {
1918                         PERROR("Failed to set session name as network destination sub-directory");
1919                         ret = -LTTNG_ERR_FATAL;
1920                         goto end;
1921                 } else if (ret >= sizeof(uris[0].subdir)) {
1922                         /* Truncated output. */
1923                         ret = -LTTNG_ERR_INVALID;
1924                         goto end;
1925                 }
1926         }
1927
1928         switch (size) {
1929         case 0:
1930                 descriptor = lttng_session_descriptor_snapshot_create(name);
1931                 break;
1932         case 1:
1933                 if (uris[0].dtype != LTTNG_DST_PATH) {
1934                         ret = -LTTNG_ERR_INVALID;
1935                         goto end;
1936                 }
1937                 descriptor = lttng_session_descriptor_snapshot_local_create(
1938                                 name,
1939                                 uris[0].dst.path);
1940                 break;
1941         case 2:
1942                 descriptor = lttng_session_descriptor_snapshot_network_create(
1943                                 name,
1944                                 snapshot_url,
1945                                 NULL);
1946                 break;
1947         default:
1948                 ret = -LTTNG_ERR_INVALID;
1949                 goto end;
1950         }
1951         if (!descriptor) {
1952                 ret = -LTTNG_ERR_INVALID;
1953                 goto end;
1954         }
1955         ret_code = lttng_create_session_ext(descriptor);
1956         ret = ret_code == LTTNG_OK ? 0 : -ret_code;
1957 end:
1958         lttng_session_descriptor_destroy(descriptor);
1959         free(uris);
1960         return ret;
1961 }
1962
1963 /*
1964  * Create a session exclusively used for live.
1965  *
1966  * Return 0 on success else a negative LTTng error code.
1967  */
1968 int lttng_create_session_live(const char *name, const char *url,
1969                 unsigned int timer_interval)
1970 {
1971         int ret;
1972         enum lttng_error_code ret_code;
1973         struct lttng_session_descriptor *descriptor = NULL;
1974
1975         if (!name) {
1976                 ret = -LTTNG_ERR_INVALID;
1977                 goto end;
1978         }
1979
1980         if (url) {
1981                 descriptor = lttng_session_descriptor_live_network_create(
1982                                 name, url, NULL, timer_interval);
1983         } else {
1984                 descriptor = lttng_session_descriptor_live_create(
1985                                 name, timer_interval);
1986         }
1987         if (!descriptor) {
1988                 ret = -LTTNG_ERR_INVALID;
1989                 goto end;
1990         }
1991         ret_code = lttng_create_session_ext(descriptor);
1992         ret = ret_code == LTTNG_OK ? 0 : -ret_code;
1993 end:
1994         lttng_session_descriptor_destroy(descriptor);
1995         return ret;
1996 }
1997
1998 /*
1999  * Stop the session and wait for the data before destroying it
2000  *
2001  * Return 0 on success else a negative LTTng error code.
2002  */
2003 int lttng_destroy_session(const char *session_name)
2004 {
2005         int ret;
2006         enum lttng_error_code ret_code;
2007         enum lttng_destruction_handle_status status;
2008         struct lttng_destruction_handle *handle = NULL;
2009
2010         /*
2011          * Stop the tracing and wait for the data to be
2012          * consumed.
2013          */
2014         ret = _lttng_stop_tracing(session_name, 1);
2015         if (ret && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
2016                 goto end;
2017         }
2018
2019         ret_code = lttng_destroy_session_ext(session_name, &handle);
2020         if (ret_code != LTTNG_OK) {
2021                 ret = (int) -ret_code;
2022                 goto end;
2023         }
2024         assert(handle);
2025
2026         /* Block until the completion of the destruction of the session. */
2027         status = lttng_destruction_handle_wait_for_completion(handle, -1);
2028         if (status != LTTNG_DESTRUCTION_HANDLE_STATUS_COMPLETED) {
2029                 ret = -LTTNG_ERR_UNK;
2030                 goto end;
2031         }
2032
2033         status = lttng_destruction_handle_get_result(handle, &ret_code);
2034         if (status != LTTNG_DESTRUCTION_HANDLE_STATUS_OK) {
2035                 ret = -LTTNG_ERR_UNK;
2036                 goto end;
2037         }
2038         ret = ret_code == LTTNG_OK ? 0 : -ret_code;
2039 end:
2040         lttng_destruction_handle_destroy(handle);
2041         return ret;
2042 }
2043
2044 /*
2045  * Destroy the session without waiting for the data.
2046  */
2047 int lttng_destroy_session_no_wait(const char *session_name)
2048 {
2049         enum lttng_error_code ret_code;
2050
2051         ret_code = lttng_destroy_session_ext(session_name, NULL);
2052         return ret_code == LTTNG_OK ? 0 : -ret_code;
2053 }
2054
2055 /*
2056  * Ask the session daemon for all available sessions.
2057  * Sets the contents of the sessions array.
2058  * Returns the number of lttng_session entries in sessions;
2059  * on error, returns a negative value.
2060  */
2061 int lttng_list_sessions(struct lttng_session **out_sessions)
2062 {
2063         int ret;
2064         struct lttcomm_session_msg lsm;
2065         const size_t session_size = sizeof(struct lttng_session) +
2066                         sizeof(struct lttng_session_extended);
2067         size_t session_count, i;
2068         struct lttng_session_extended *sessions_extended_begin;
2069         struct lttng_session *sessions = NULL;
2070
2071         memset(&lsm, 0, sizeof(lsm));
2072         lsm.cmd_type = LTTNG_LIST_SESSIONS;
2073         /*
2074          * Initialize out_sessions to NULL so it is initialized when
2075          * lttng_list_sessions returns 0, thus allowing *out_sessions to
2076          * be subsequently freed.
2077          */
2078         *out_sessions = NULL;
2079         ret = lttng_ctl_ask_sessiond(&lsm, (void**) &sessions);
2080         if (ret <= 0) {
2081                 goto end;
2082         }
2083         if (!sessions) {
2084                 ret = -LTTNG_ERR_FATAL;
2085                 goto end;
2086         }
2087
2088         if (ret % session_size) {
2089                 ret = -LTTNG_ERR_UNK;
2090                 free(sessions);
2091                 goto end;
2092         }
2093         session_count = (size_t) ret / session_size;
2094         sessions_extended_begin = (struct lttng_session_extended *)
2095                         (&sessions[session_count]);
2096
2097         /* Set extended session info pointers. */
2098         for (i = 0; i < session_count; i++) {
2099                 struct lttng_session *session = &sessions[i];
2100                 struct lttng_session_extended *extended =
2101                                 &(sessions_extended_begin[i]);
2102
2103                 session->extended.ptr = extended;
2104         }
2105
2106         ret = (int) session_count;
2107         *out_sessions = sessions;
2108 end:
2109         return ret;
2110 }
2111
2112 enum lttng_error_code lttng_session_get_creation_time(
2113                 const struct lttng_session *session, uint64_t *creation_time)
2114 {
2115         enum lttng_error_code ret = LTTNG_OK;
2116         struct lttng_session_extended *extended;
2117
2118         if (!session || !creation_time || !session->extended.ptr) {
2119                 ret = LTTNG_ERR_INVALID;
2120                 goto end;
2121         }
2122
2123         extended = session->extended.ptr;
2124         if (!extended->creation_time.is_set) {
2125                 /* Not created on the session daemon yet. */
2126                 ret = LTTNG_ERR_SESSION_NOT_EXIST;
2127                 goto end;
2128         }
2129         *creation_time = extended->creation_time.value;
2130 end:
2131         return ret;
2132 }
2133
2134 int lttng_set_session_shm_path(const char *session_name,
2135                 const char *shm_path)
2136 {
2137         int ret;
2138         struct lttcomm_session_msg lsm;
2139
2140         if (session_name == NULL) {
2141                 return -LTTNG_ERR_INVALID;
2142         }
2143
2144         memset(&lsm, 0, sizeof(lsm));
2145         lsm.cmd_type = LTTNG_SET_SESSION_SHM_PATH;
2146
2147         ret = lttng_strncpy(lsm.session.name, session_name,
2148                         sizeof(lsm.session.name));
2149         if (ret) {
2150                 ret = -LTTNG_ERR_INVALID;
2151                 goto end;
2152         }
2153
2154         ret = lttng_strncpy(lsm.u.set_shm_path.shm_path, shm_path ?: "",
2155                         sizeof(lsm.u.set_shm_path.shm_path));
2156         if (ret) {
2157                 ret = -LTTNG_ERR_INVALID;
2158                 goto end;
2159         }
2160
2161         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
2162 end:
2163         return ret;
2164 }
2165
2166 /*
2167  * Ask the session daemon for all available domains of a session.
2168  * Sets the contents of the domains array.
2169  * Returns the number of lttng_domain entries in domains;
2170  * on error, returns a negative value.
2171  */
2172 int lttng_list_domains(const char *session_name,
2173                 struct lttng_domain **domains)
2174 {
2175         int ret;
2176         struct lttcomm_session_msg lsm;
2177
2178         if (session_name == NULL) {
2179                 ret = -LTTNG_ERR_INVALID;
2180                 goto error;
2181         }
2182
2183         memset(&lsm, 0, sizeof(lsm));
2184         lsm.cmd_type = LTTNG_LIST_DOMAINS;
2185
2186         ret = lttng_strncpy(lsm.session.name, session_name,
2187                         sizeof(lsm.session.name));
2188         if (ret) {
2189                 ret = -LTTNG_ERR_INVALID;
2190                 goto error;
2191         }
2192
2193         ret = lttng_ctl_ask_sessiond(&lsm, (void**) domains);
2194         if (ret < 0) {
2195                 goto error;
2196         }
2197
2198         return ret / sizeof(struct lttng_domain);
2199 error:
2200         return ret;
2201 }
2202
2203 /*
2204  * Ask the session daemon for all available channels of a session.
2205  * Sets the contents of the channels array.
2206  * Returns the number of lttng_channel entries in channels;
2207  * on error, returns a negative value.
2208  */
2209 int lttng_list_channels(struct lttng_handle *handle,
2210                 struct lttng_channel **channels)
2211 {
2212         int ret, total_payload_received;
2213         struct lttcomm_session_msg lsm;
2214         char *reception_buffer = NULL;
2215         size_t cmd_header_len = 0;
2216         struct lttcomm_list_command_header *cmd_header = NULL;
2217         struct lttng_dynamic_buffer tmp_buffer;
2218
2219         lttng_dynamic_buffer_init(&tmp_buffer);
2220
2221         if (handle == NULL) {
2222                 ret = -LTTNG_ERR_INVALID;
2223                 goto end;
2224         }
2225
2226         memset(&lsm, 0, sizeof(lsm));
2227         lsm.cmd_type = LTTNG_LIST_CHANNELS;
2228         ret = lttng_strncpy(lsm.session.name, handle->session_name,
2229                         sizeof(lsm.session.name));
2230         if (ret) {
2231                 ret = -LTTNG_ERR_INVALID;
2232                 goto end;
2233         }
2234
2235         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
2236
2237         ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
2238                         (void **) &reception_buffer, (void **) &cmd_header,
2239                         &cmd_header_len);
2240         if (ret < 0) {
2241                 goto end;
2242         }
2243
2244         total_payload_received = ret;
2245
2246         if (cmd_header_len != sizeof(*cmd_header)) {
2247                 ret = -LTTNG_ERR_FATAL;
2248                 goto end;
2249         }
2250
2251         if (!cmd_header) {
2252                 ret = LTTNG_ERR_UNK;
2253                 goto end;
2254         }
2255
2256         if (cmd_header->count > INT_MAX) {
2257                 ret = -LTTNG_ERR_OVERFLOW;
2258                 goto end;
2259         }
2260
2261         {
2262                 enum lttng_error_code ret_code;
2263                 const struct lttng_buffer_view events_view =
2264                                 lttng_buffer_view_init(reception_buffer, 0,
2265                                                 total_payload_received);
2266
2267                 ret_code = lttng_channels_create_and_flatten_from_buffer(
2268                                 &events_view, cmd_header->count, channels);
2269                 if (ret_code != LTTNG_OK) {
2270                         ret = -ret_code;
2271                         goto end;
2272                 }
2273         }
2274
2275         ret = (int) cmd_header->count;
2276 end:
2277         free(cmd_header);
2278         free(reception_buffer);
2279         return ret;
2280 }
2281
2282 /*
2283  * Ask the session daemon for all available events of a session channel.
2284  * Sets the contents of the events array.
2285  * Returns the number of lttng_event entries in events;
2286  * on error, returns a negative value.
2287  */
2288 int lttng_list_events(struct lttng_handle *handle,
2289                 const char *channel_name, struct lttng_event **events)
2290 {
2291         enum lttng_error_code ret_code;
2292         int ret;
2293         struct lttcomm_session_msg lsm;
2294         struct lttcomm_list_command_header *cmd_header = NULL;
2295         size_t cmd_header_len;
2296         unsigned int nb_events;
2297         char *reception_buffer = NULL;
2298         struct lttng_dynamic_buffer tmp_buffer;
2299         ssize_t total_payload_received;
2300
2301         lttng_dynamic_buffer_init(&tmp_buffer);
2302
2303         /* Safety check. An handle and channel name are mandatory */
2304         if (handle == NULL || channel_name == NULL) {
2305                 return -LTTNG_ERR_INVALID;
2306         }
2307
2308         memset(&lsm, 0, sizeof(lsm));
2309         lsm.cmd_type = LTTNG_LIST_EVENTS;
2310         ret = lttng_strncpy(lsm.session.name, handle->session_name,
2311                         sizeof(lsm.session.name));
2312         if (ret) {
2313                 ret = -LTTNG_ERR_INVALID;
2314                 goto end;
2315         }
2316
2317         ret = lttng_strncpy(lsm.u.list.channel_name, channel_name,
2318                         sizeof(lsm.u.list.channel_name));
2319         if (ret) {
2320                 ret = -LTTNG_ERR_INVALID;
2321                 goto end;
2322         }
2323
2324         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
2325
2326         ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
2327                 (void **) &reception_buffer, (void **) &cmd_header,
2328                 &cmd_header_len);
2329         if (ret < 0) {
2330                 goto end;
2331         }
2332
2333         total_payload_received = ret;
2334
2335         if (!cmd_header) {
2336                 ret = -LTTNG_ERR_UNK;
2337                 goto end;
2338         }
2339
2340         if (cmd_header->count > INT_MAX) {
2341                 ret = -LTTNG_ERR_OVERFLOW;
2342                 goto end;
2343         }
2344
2345         nb_events = (unsigned int) cmd_header->count;
2346
2347         {
2348                 const struct lttng_buffer_view events_view =
2349                                 lttng_buffer_view_init(reception_buffer, 0,
2350                                                 total_payload_received);
2351                 ret_code = lttng_events_create_and_flatten_from_buffer(
2352                                 &events_view, nb_events, events);
2353                 if (ret_code != LTTNG_OK) {
2354                         ret = -ret_code;
2355                         goto end;
2356                 }
2357         }
2358
2359         ret = (int) nb_events;
2360 end:
2361         free(cmd_header);
2362         free(reception_buffer);
2363         return ret;
2364 }
2365
2366 /*
2367  * Sets the tracing_group variable with name.
2368  * This function allocates memory pointed to by tracing_group.
2369  * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
2370  */
2371 int lttng_set_tracing_group(const char *name)
2372 {
2373         char *new_group;
2374         if (name == NULL) {
2375                 return -LTTNG_ERR_INVALID;
2376         }
2377
2378         if (asprintf(&new_group, "%s", name) < 0) {
2379                 return -LTTNG_ERR_FATAL;
2380         }
2381
2382         free(tracing_group);
2383         tracing_group = new_group;
2384         new_group = NULL;
2385
2386         return 0;
2387 }
2388
2389 int lttng_calibrate(struct lttng_handle *handle,
2390                 struct lttng_calibrate *calibrate)
2391 {
2392         /*
2393          * This command was removed in LTTng 2.9.
2394          */
2395         return -LTTNG_ERR_UND;
2396 }
2397
2398 /*
2399  * Set default channel attributes.
2400  * If either or both of the arguments are null, attr content is zeroe'd.
2401  */
2402 void lttng_channel_set_default_attr(struct lttng_domain *domain,
2403                 struct lttng_channel_attr *attr)
2404 {
2405         struct lttng_channel_extended *extended;
2406
2407         /* Safety check */
2408         if (attr == NULL || domain == NULL) {
2409                 return;
2410         }
2411
2412         /* Save the pointer for later use */
2413         extended = (struct lttng_channel_extended *) attr->extended.ptr;
2414         memset(attr, 0, sizeof(struct lttng_channel_attr));
2415
2416         /* Same for all domains. */
2417         attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
2418         attr->tracefile_size = DEFAULT_CHANNEL_TRACEFILE_SIZE;
2419         attr->tracefile_count = DEFAULT_CHANNEL_TRACEFILE_COUNT;
2420
2421         switch (domain->type) {
2422         case LTTNG_DOMAIN_KERNEL:
2423                 attr->switch_timer_interval =
2424                                 DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
2425                 attr->read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
2426                 attr->subbuf_size = default_get_kernel_channel_subbuf_size();
2427                 attr->num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
2428                 attr->output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
2429                 break;
2430         case LTTNG_DOMAIN_UST:
2431                 switch (domain->buf_type) {
2432                 case LTTNG_BUFFER_PER_UID:
2433                         attr->subbuf_size = default_get_ust_uid_channel_subbuf_size();
2434                         attr->num_subbuf = DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM;
2435                         attr->output = DEFAULT_UST_UID_CHANNEL_OUTPUT;
2436                         attr->switch_timer_interval =
2437                                         DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER;
2438                         attr->read_timer_interval =
2439                                         DEFAULT_UST_UID_CHANNEL_READ_TIMER;
2440                         break;
2441                 case LTTNG_BUFFER_PER_PID:
2442                 default:
2443                         attr->subbuf_size = default_get_ust_pid_channel_subbuf_size();
2444                         attr->num_subbuf = DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM;
2445                         attr->output = DEFAULT_UST_PID_CHANNEL_OUTPUT;
2446                         attr->switch_timer_interval =
2447                                         DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER;
2448                         attr->read_timer_interval =
2449                                         DEFAULT_UST_PID_CHANNEL_READ_TIMER;
2450                         break;
2451                 }
2452         default:
2453                 /* Default behavior: leave set to 0. */
2454                 break;
2455         }
2456
2457         if (extended) {
2458                 lttng_channel_set_default_extended_attr(domain, extended);
2459         }
2460
2461         /* Reassign the extended pointer. */
2462         attr->extended.ptr = extended;
2463 }
2464
2465 int lttng_channel_get_discarded_event_count(struct lttng_channel *channel,
2466                 uint64_t *discarded_events)
2467 {
2468         int ret = 0;
2469         struct lttng_channel_extended *chan_ext;
2470
2471         if (!channel || !discarded_events) {
2472                 ret = -LTTNG_ERR_INVALID;
2473                 goto end;
2474         }
2475
2476         chan_ext = channel->attr.extended.ptr;
2477         if (!chan_ext) {
2478                 /*
2479                  * This can happen since the lttng_channel structure is
2480                  * used for other tasks where this pointer is never set.
2481                  */
2482                 *discarded_events = 0;
2483                 goto end;
2484         }
2485
2486         *discarded_events = chan_ext->discarded_events;
2487 end:
2488         return ret;
2489 }
2490
2491 int lttng_channel_get_lost_packet_count(struct lttng_channel *channel,
2492                 uint64_t *lost_packets)
2493 {
2494         int ret = 0;
2495         struct lttng_channel_extended *chan_ext;
2496
2497         if (!channel || !lost_packets) {
2498                 ret = -LTTNG_ERR_INVALID;
2499                 goto end;
2500         }
2501
2502         chan_ext = channel->attr.extended.ptr;
2503         if (!chan_ext) {
2504                 /*
2505                  * This can happen since the lttng_channel structure is
2506                  * used for other tasks where this pointer is never set.
2507                  */
2508                 *lost_packets = 0;
2509                 goto end;
2510         }
2511
2512         *lost_packets = chan_ext->lost_packets;
2513 end:
2514         return ret;
2515 }
2516
2517 int lttng_channel_get_monitor_timer_interval(struct lttng_channel *chan,
2518                 uint64_t *monitor_timer_interval)
2519 {
2520         int ret = 0;
2521
2522         if (!chan || !monitor_timer_interval) {
2523                 ret = -LTTNG_ERR_INVALID;
2524                 goto end;
2525         }
2526
2527         if (!chan->attr.extended.ptr) {
2528                 ret = -LTTNG_ERR_INVALID;
2529                 goto end;
2530         }
2531
2532         *monitor_timer_interval = ((struct lttng_channel_extended *)
2533                         chan->attr.extended.ptr)->monitor_timer_interval;
2534 end:
2535         return ret;
2536 }
2537
2538 int lttng_channel_set_monitor_timer_interval(struct lttng_channel *chan,
2539                 uint64_t monitor_timer_interval)
2540 {
2541         int ret = 0;
2542
2543         if (!chan || !chan->attr.extended.ptr) {
2544                 ret = -LTTNG_ERR_INVALID;
2545                 goto end;
2546         }
2547
2548         ((struct lttng_channel_extended *)
2549                         chan->attr.extended.ptr)->monitor_timer_interval =
2550                         monitor_timer_interval;
2551 end:
2552         return ret;
2553 }
2554
2555 int lttng_channel_get_blocking_timeout(struct lttng_channel *chan,
2556                 int64_t *blocking_timeout)
2557 {
2558         int ret = 0;
2559
2560         if (!chan || !blocking_timeout) {
2561                 ret = -LTTNG_ERR_INVALID;
2562                 goto end;
2563         }
2564
2565         if (!chan->attr.extended.ptr) {
2566                 ret = -LTTNG_ERR_INVALID;
2567                 goto end;
2568         }
2569
2570         *blocking_timeout = ((struct lttng_channel_extended *)
2571                         chan->attr.extended.ptr)->blocking_timeout;
2572 end:
2573         return ret;
2574 }
2575
2576 int lttng_channel_set_blocking_timeout(struct lttng_channel *chan,
2577                 int64_t blocking_timeout)
2578 {
2579         int ret = 0;
2580         int64_t msec_timeout;
2581
2582         if (!chan || !chan->attr.extended.ptr) {
2583                 ret = -LTTNG_ERR_INVALID;
2584                 goto end;
2585         }
2586
2587         if (blocking_timeout < 0 && blocking_timeout != -1) {
2588                 ret = -LTTNG_ERR_INVALID;
2589                 goto end;
2590         }
2591
2592         /*
2593          * LTTng-ust's use of poll() to implement this timeout mechanism forces
2594          * us to accept a narrower range of values (msecs expressed as a signed
2595          * 32-bit integer).
2596          */
2597         msec_timeout = blocking_timeout / 1000;
2598         if (msec_timeout != (int32_t) msec_timeout) {
2599                 ret = -LTTNG_ERR_INVALID;
2600                 goto end;
2601         }
2602
2603         ((struct lttng_channel_extended *)
2604                         chan->attr.extended.ptr)->blocking_timeout =
2605                         blocking_timeout;
2606 end:
2607         return ret;
2608 }
2609
2610 /*
2611  * Check if session daemon is alive.
2612  *
2613  * Return 1 if alive or 0 if not.
2614  * On error returns a negative value.
2615  */
2616 int lttng_session_daemon_alive(void)
2617 {
2618         int ret;
2619
2620         ret = set_session_daemon_path();
2621         if (ret < 0) {
2622                 /* Error. */
2623                 return ret;
2624         }
2625
2626         if (*sessiond_sock_path == '\0') {
2627                 /*
2628                  * No socket path set. Weird error which means the constructor
2629                  * was not called.
2630                  */
2631                 assert(0);
2632         }
2633
2634         ret = try_connect_sessiond(sessiond_sock_path);
2635         if (ret < 0) {
2636                 /* Not alive. */
2637                 return 0;
2638         }
2639
2640         /* Is alive. */
2641         return 1;
2642 }
2643
2644 /*
2645  * Set URL for a consumer for a session and domain.
2646  *
2647  * Return 0 on success, else a negative value.
2648  */
2649 int lttng_set_consumer_url(struct lttng_handle *handle,
2650                 const char *control_url, const char *data_url)
2651 {
2652         int ret;
2653         ssize_t size;
2654         struct lttcomm_session_msg lsm;
2655         struct lttng_uri *uris = NULL;
2656
2657         if (handle == NULL || (control_url == NULL && data_url == NULL)) {
2658                 ret = -LTTNG_ERR_INVALID;
2659                 goto error;
2660         }
2661
2662         memset(&lsm, 0, sizeof(lsm));
2663
2664         lsm.cmd_type = LTTNG_SET_CONSUMER_URI;
2665
2666         ret = lttng_strncpy(lsm.session.name, handle->session_name,
2667                         sizeof(lsm.session.name));
2668         if (ret) {
2669                 ret = -LTTNG_ERR_INVALID;
2670                 goto error;
2671         }
2672
2673         COPY_DOMAIN_PACKED(lsm.domain, handle->domain);
2674
2675         size = uri_parse_str_urls(control_url, data_url, &uris);
2676         if (size < 0) {
2677                 ret = -LTTNG_ERR_INVALID;
2678                 goto error;
2679         }
2680
2681         lsm.u.uri.size = size;
2682
2683         ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, uris,
2684                         sizeof(struct lttng_uri) * size, NULL);
2685
2686         free(uris);
2687 error:
2688         return ret;
2689 }
2690
2691 /*
2692  * [OBSOLETE]
2693  */
2694 int lttng_enable_consumer(struct lttng_handle *handle);
2695 int lttng_enable_consumer(struct lttng_handle *handle)
2696 {
2697         return -ENOSYS;
2698 }
2699
2700 /*
2701  * [OBSOLETE]
2702  */
2703 int lttng_disable_consumer(struct lttng_handle *handle);
2704 int lttng_disable_consumer(struct lttng_handle *handle)
2705 {
2706         return -ENOSYS;
2707 }
2708
2709 /*
2710  * [OBSOLETE]
2711  */
2712 int _lttng_create_session_ext(const char *name, const char *url,
2713                 const char *datetime);
2714 int _lttng_create_session_ext(const char *name, const char *url,
2715                 const char *datetime)
2716 {
2717         return -ENOSYS;
2718 }
2719
2720 /*
2721  * For a given session name, this call checks if the data is ready to be read
2722  * or is still being extracted by the consumer(s) hence not ready to be used by
2723  * any readers.
2724  */
2725 int lttng_data_pending(const char *session_name)
2726 {
2727         int ret;
2728         struct lttcomm_session_msg lsm;
2729         uint8_t *pending = NULL;
2730
2731         if (session_name == NULL) {
2732                 return -LTTNG_ERR_INVALID;
2733         }
2734
2735         memset(&lsm, 0, sizeof(lsm));
2736         lsm.cmd_type = LTTNG_DATA_PENDING;
2737
2738         ret = lttng_strncpy(lsm.session.name, session_name,
2739                         sizeof(lsm.session.name));
2740         if (ret) {
2741                 ret = -LTTNG_ERR_INVALID;
2742                 goto end;
2743         }
2744
2745         ret = lttng_ctl_ask_sessiond(&lsm, (void **) &pending);
2746         if (ret < 0) {
2747                 goto end;
2748         } else if (ret != 1) {
2749                 /* Unexpected payload size */
2750                 ret = -LTTNG_ERR_INVALID;
2751                 goto end;
2752         } else if (!pending) {
2753                 /* Internal error. */
2754                 ret = -LTTNG_ERR_UNK;
2755                 goto end;
2756         }
2757
2758         ret = (int) *pending;
2759 end:
2760         free(pending);
2761         return ret;
2762 }
2763
2764 /*
2765  * Regenerate the metadata for a session.
2766  * Return 0 on success, a negative error code on error.
2767  */
2768 int lttng_regenerate_metadata(const char *session_name)
2769 {
2770         int ret;
2771         struct lttcomm_session_msg lsm;
2772
2773         if (!session_name) {
2774                 ret = -LTTNG_ERR_INVALID;
2775                 goto end;
2776         }
2777
2778         memset(&lsm, 0, sizeof(lsm));
2779         lsm.cmd_type = LTTNG_REGENERATE_METADATA;
2780
2781         ret = lttng_strncpy(lsm.session.name, session_name,
2782                         sizeof(lsm.session.name));
2783         if (ret) {
2784                 ret = -LTTNG_ERR_INVALID;
2785                 goto end;
2786         }
2787
2788         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
2789         if (ret < 0) {
2790                 goto end;
2791         }
2792
2793         ret = 0;
2794 end:
2795         return ret;
2796 }
2797
2798 /*
2799  * Deprecated, replaced by lttng_regenerate_metadata.
2800  */
2801 int lttng_metadata_regenerate(const char *session_name)
2802 {
2803         return lttng_regenerate_metadata(session_name);
2804 }
2805
2806 /*
2807  * Regenerate the statedump of a session.
2808  * Return 0 on success, a negative error code on error.
2809  */
2810 int lttng_regenerate_statedump(const char *session_name)
2811 {
2812         int ret;
2813         struct lttcomm_session_msg lsm;
2814
2815         if (!session_name) {
2816                 ret = -LTTNG_ERR_INVALID;
2817                 goto end;
2818         }
2819
2820         memset(&lsm, 0, sizeof(lsm));
2821         lsm.cmd_type = LTTNG_REGENERATE_STATEDUMP;
2822
2823         ret = lttng_strncpy(lsm.session.name, session_name,
2824                         sizeof(lsm.session.name));
2825         if (ret) {
2826                 ret = -LTTNG_ERR_INVALID;
2827                 goto end;
2828         }
2829
2830         ret = lttng_ctl_ask_sessiond(&lsm, NULL);
2831         if (ret < 0) {
2832                 goto end;
2833         }
2834
2835         ret = 0;
2836 end:
2837         return ret;
2838 }
2839
2840 int lttng_register_trigger(struct lttng_trigger *trigger)
2841 {
2842         int ret;
2843         struct lttcomm_session_msg lsm;
2844         struct lttng_dynamic_buffer buffer;
2845
2846         lttng_dynamic_buffer_init(&buffer);
2847         if (!trigger) {
2848                 ret = -LTTNG_ERR_INVALID;
2849                 goto end;
2850         }
2851
2852         if (!lttng_trigger_validate(trigger)) {
2853                 ret = -LTTNG_ERR_INVALID_TRIGGER;
2854                 goto end;
2855         }
2856
2857         ret = lttng_trigger_serialize(trigger, &buffer);
2858         if (ret < 0) {
2859                 ret = -LTTNG_ERR_UNK;
2860                 goto end;
2861         }
2862
2863         memset(&lsm, 0, sizeof(lsm));
2864         lsm.cmd_type = LTTNG_REGISTER_TRIGGER;
2865         lsm.u.trigger.length = (uint32_t) buffer.size;
2866         ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, buffer.data,
2867                         buffer.size, NULL);
2868 end:
2869         lttng_dynamic_buffer_reset(&buffer);
2870         return ret;
2871 }
2872
2873 int lttng_unregister_trigger(struct lttng_trigger *trigger)
2874 {
2875         int ret;
2876         struct lttcomm_session_msg lsm;
2877         struct lttng_dynamic_buffer buffer;
2878
2879         lttng_dynamic_buffer_init(&buffer);
2880         if (!trigger) {
2881                 ret = -LTTNG_ERR_INVALID;
2882                 goto end;
2883         }
2884
2885         if (!lttng_trigger_validate(trigger)) {
2886                 ret = -LTTNG_ERR_INVALID_TRIGGER;
2887                 goto end;
2888         }
2889
2890         ret = lttng_trigger_serialize(trigger, &buffer);
2891         if (ret < 0) {
2892                 ret = -LTTNG_ERR_UNK;
2893                 goto end;
2894         }
2895
2896         memset(&lsm, 0, sizeof(lsm));
2897         lsm.cmd_type = LTTNG_UNREGISTER_TRIGGER;
2898         lsm.u.trigger.length = (uint32_t) buffer.size;
2899         ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, buffer.data,
2900                         buffer.size, NULL);
2901 end:
2902         lttng_dynamic_buffer_reset(&buffer);
2903         return ret;
2904 }
2905
2906 /*
2907  * lib constructor.
2908  */
2909 static void __attribute__((constructor)) init(void)
2910 {
2911         /* Set default session group */
2912         lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
2913 }
2914
2915 /*
2916  * lib destructor.
2917  */
2918 static void __attribute__((destructor)) lttng_ctl_exit(void)
2919 {
2920         free(tracing_group);
2921 }