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

   1 /*
   2  * liblttngctl.c
   3  *
   4  * Linux Trace Toolkit Control Library
   5  *
   6  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   7  *
   8  * This library is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License, version 2.1 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this library; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #define _GNU_SOURCE
  23 #include <grp.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <unistd.h>
  29
  30 #include <common/common.h>
  31 #include <common/defaults.h>
  32 #include <common/sessiond-comm/sessiond-comm.h>
  33 #include <lttng/lttng.h>
  34
  35 #include "filter-parser.h"
  36 #include "filter-ast.h"
  37 #include "filter-bytecode.h"
  38 #include "memstream.h"
  39
  40 #ifdef DEBUG
  41 const int print_xml = 1;
  42 #define dbg_printf(fmt, args...)        \
  43         printf("[debug liblttng-ctl] " fmt, ## args)
  44 #else
  45 const int print_xml = 0;
  46 #define dbg_printf(fmt, args...)                                \
  47 do {                                                            \
  48         /* do nothing but check printf format */                \
  49         if (0)                                                  \
  50                 printf("[debug liblttnctl] " fmt, ## args);     \
  51 } while (0)
  52 #endif
  53
  54
  55 /* Socket to session daemon for communication */
  56 static int sessiond_socket;
  57 static char sessiond_sock_path[PATH_MAX];
  58
  59 /* Variables */
  60 static char *tracing_group;
  61 static int connected;
  62
  63 /* Global */
  64
  65 /*
  66  * Those two variables are used by error.h to silent or control the verbosity of
  67  * error message. They are global to the library so application linking with it
  68  * are able to compile correctly and also control verbosity of the library.
  69  *
  70  * Note that it is *not* possible to silent ERR() and PERROR() macros.
  71  */
  72 int lttng_opt_quiet;
  73 int lttng_opt_verbose;
  74
  75 /*
  76  * Copy string from src to dst and enforce null terminated byte.
  77  */
  78 static void copy_string(char *dst, const char *src, size_t len)
  79 {
  80         if (src && dst) {
  81                 strncpy(dst, src, len);
  82                 /* Enforce the NULL terminated byte */
  83                 dst[len - 1] = '\0';
  84         } else if (dst) {
  85                 dst[0] = '\0';
  86         }
  87 }
  88
  89 /*
  90  * Copy domain to lttcomm_session_msg domain.
  91  *
  92  * If domain is unknown, default domain will be the kernel.
  93  */
  94 static void copy_lttng_domain(struct lttng_domain *dst, struct lttng_domain *src)
  95 {
  96         if (src && dst) {
  97                 switch (src->type) {
  98                 case LTTNG_DOMAIN_KERNEL:
  99                 case LTTNG_DOMAIN_UST:
 100                 /*
 101                 case LTTNG_DOMAIN_UST_EXEC_NAME:
 102                 case LTTNG_DOMAIN_UST_PID:
 103                 case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
 104                 */
 105                         memcpy(dst, src, sizeof(struct lttng_domain));
 106                         break;
 107                 default:
 108                         memset(dst, 0, sizeof(struct lttng_domain));
 109                         dst->type = LTTNG_DOMAIN_KERNEL;
 110                         break;
 111                 }
 112         }
 113 }
 114
 115 /*
 116  * Send lttcomm_session_msg to the session daemon.
 117  *
 118  * On success, returns the number of bytes sent (>=0)
 119  * On error, returns -1
 120  */
 121 static int send_session_msg(struct lttcomm_session_msg *lsm)
 122 {
 123         int ret;
 124
 125         if (!connected) {
 126                 ret = -ENOTCONN;
 127                 goto end;
 128         }
 129
 130         ret = lttcomm_send_creds_unix_sock(sessiond_socket, lsm,
 131                         sizeof(struct lttcomm_session_msg));
 132
 133 end:
 134         return ret;
 135 }
 136
 137 /*
 138  * Send var len data to the session daemon.
 139  *
 140  * On success, returns the number of bytes sent (>=0)
 141  * On error, returns -1
 142  */
 143 static int send_session_varlen(void *data, size_t len)
 144 {
 145         int ret;
 146
 147         if (!connected) {
 148                 ret = -ENOTCONN;
 149                 goto end;
 150         }
 151         if (!data || !len) {
 152                 ret = 0;
 153                 goto end;
 154         }
 155
 156         ret = lttcomm_send_unix_sock(sessiond_socket, data, len);
 157
 158 end:
 159         return ret;
 160 }
 161
 162 /*
 163  * Receive data from the sessiond socket.
 164  *
 165  * On success, returns the number of bytes received (>=0)
 166  * On error, returns -1 (recvmsg() error) or -ENOTCONN
 167  */
 168 static int recv_data_sessiond(void *buf, size_t len)
 169 {
 170         int ret;
 171
 172         if (!connected) {
 173                 ret = -ENOTCONN;
 174                 goto end;
 175         }
 176
 177         ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
 178
 179 end:
 180         return ret;
 181 }
 182
 183 /*
 184  *  Check if we are in the specified group.
 185  *
 186  *  If yes return 1, else return -1.
 187  */
 188 static int check_tracing_group(const char *grp_name)
 189 {
 190         struct group *grp_tracing;      /* no free(). See getgrnam(3) */
 191         gid_t *grp_list;
 192         int grp_list_size, grp_id, i;
 193         int ret = -1;
 194
 195         /* Get GID of group 'tracing' */
 196         grp_tracing = getgrnam(grp_name);
 197         if (!grp_tracing) {
 198                 /* If grp_tracing is NULL, the group does not exist. */
 199                 goto end;
 200         }
 201
 202         /* Get number of supplementary group IDs */
 203         grp_list_size = getgroups(0, NULL);
 204         if (grp_list_size < 0) {
 205                 perror("getgroups");
 206                 goto end;
 207         }
 208
 209         /* Alloc group list of the right size */
 210         grp_list = malloc(grp_list_size * sizeof(gid_t));
 211         if (!grp_list) {
 212                 perror("malloc");
 213                 goto end;
 214         }
 215         grp_id = getgroups(grp_list_size, grp_list);
 216         if (grp_id < 0) {
 217                 perror("getgroups");
 218                 goto free_list;
 219         }
 220
 221         for (i = 0; i < grp_list_size; i++) {
 222                 if (grp_list[i] == grp_tracing->gr_gid) {
 223                         ret = 1;
 224                         break;
 225                 }
 226         }
 227
 228 free_list:
 229         free(grp_list);
 230
 231 end:
 232         return ret;
 233 }
 234
 235 /*
 236  * Try connect to session daemon with sock_path.
 237  *
 238  * Return 0 on success, else -1
 239  */
 240 static int try_connect_sessiond(const char *sock_path)
 241 {
 242         int ret;
 243
 244         /* If socket exist, we check if the daemon listens for connect. */
 245         ret = access(sock_path, F_OK);
 246         if (ret < 0) {
 247                 /* Not alive */
 248                 return -1;
 249         }
 250
 251         ret = lttcomm_connect_unix_sock(sock_path);
 252         if (ret < 0) {
 253                 /* Not alive */
 254                 return -1;
 255         }
 256
 257         ret = lttcomm_close_unix_sock(ret);
 258         if (ret < 0) {
 259                 perror("lttcomm_close_unix_sock");
 260         }
 261
 262         return 0;
 263 }
 264
 265 /*
 266  * Set sessiond socket path by putting it in the global
 267  * sessiond_sock_path variable.
 268  * Returns 0 on success,
 269  * -ENOMEM on failure (the sessiond socket path is somehow too long)
 270  */
 271 static int set_session_daemon_path(void)
 272 {
 273         int ret;
 274         int in_tgroup = 0;      /* In tracing group */
 275         uid_t uid;
 276
 277         uid = getuid();
 278
 279         if (uid != 0) {
 280                 /* Are we in the tracing group ? */
 281                 in_tgroup = check_tracing_group(tracing_group);
 282         }
 283
 284         if ((uid == 0) || in_tgroup) {
 285                 copy_string(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 286                                 sizeof(sessiond_sock_path));
 287         }
 288
 289         if (uid != 0) {
 290                 if (in_tgroup) {
 291                         /* Tracing group */
 292                         ret = try_connect_sessiond(sessiond_sock_path);
 293                         if (ret >= 0) {
 294                                 goto end;
 295                         }
 296                         /* Global session daemon not available... */
 297                 }
 298                 /* ...or not in tracing group (and not root), default */
 299
 300                 /*
 301                  * With GNU C <  2.1, snprintf returns -1 if the target buffer is too small;
 302                  * With GNU C >= 2.1, snprintf returns the required size (excluding closing null)
 303                  */
 304                 ret = snprintf(sessiond_sock_path, sizeof(sessiond_sock_path),
 305                                 DEFAULT_HOME_CLIENT_UNIX_SOCK, getenv("HOME"));
 306                 if ((ret < 0) || (ret >= sizeof(sessiond_sock_path))) {
 307                         return -ENOMEM;
 308                 }
 309         }
 310 end:
 311         return 0;
 312 }
 313
 314 /*
 315  *  Connect to the LTTng session daemon.
 316  *
 317  *  On success, return 0. On error, return -1.
 318  */
 319 static int connect_sessiond(void)
 320 {
 321         int ret;
 322
 323         ret = set_session_daemon_path();
 324         if (ret < 0) {
 325                 return -1; /* set_session_daemon_path() returns -ENOMEM */
 326         }
 327
 328         /* Connect to the sesssion daemon */
 329         ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 330         if (ret < 0) {
 331                 return ret;
 332         }
 333
 334         sessiond_socket = ret;
 335         connected = 1;
 336
 337         return 0;
 338 }
 339
 340 /*
 341  *  Clean disconnect from the session daemon.
 342  *  On success, return 0. On error, return -1.
 343  */
 344 static int disconnect_sessiond(void)
 345 {
 346         int ret = 0;
 347
 348         if (connected) {
 349                 ret = lttcomm_close_unix_sock(sessiond_socket);
 350                 sessiond_socket = 0;
 351                 connected = 0;
 352         }
 353
 354         return ret;
 355 }
 356
 357 /*
 358  * Ask the session daemon a specific command and put the data into buf.
 359  * Takes extra var. len. data as input to send to the session daemon.
 360  *
 361  * Return size of data (only payload, not header) or a negative error code.
 362  */
 363 static int ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
 364                 void *vardata,
 365                 size_t varlen,
 366                 void **buf)
 367 {
 368         int ret;
 369         size_t size;
 370         void *data = NULL;
 371         struct lttcomm_lttng_msg llm;
 372
 373         ret = connect_sessiond();
 374         if (ret < 0) {
 375                 goto end;
 376         }
 377
 378         /* Send command to session daemon */
 379         ret = send_session_msg(lsm);
 380         if (ret < 0) {
 381                 goto end;
 382         }
 383         /* Send var len data */
 384         ret = send_session_varlen(vardata, varlen);
 385         if (ret < 0) {
 386                 goto end;
 387         }
 388
 389         /* Get header from data transmission */
 390         ret = recv_data_sessiond(&llm, sizeof(llm));
 391         if (ret < 0) {
 392                 goto end;
 393         }
 394
 395         /* Check error code if OK */
 396         if (llm.ret_code != LTTCOMM_OK) {
 397                 ret = -llm.ret_code;
 398                 goto end;
 399         }
 400
 401         size = llm.data_size;
 402         if (size == 0) {
 403                 /* If client free with size 0 */
 404                 if (buf != NULL) {
 405                         *buf = NULL;
 406                 }
 407                 ret = 0;
 408                 goto end;
 409         }
 410
 411         data = (void*) malloc(size);
 412
 413         /* Get payload data */
 414         ret = recv_data_sessiond(data, size);
 415         if (ret < 0) {
 416                 free(data);
 417                 goto end;
 418         }
 419
 420         /*
 421          * Extra protection not to dereference a NULL pointer. If buf is NULL at
 422          * this point, an error is returned and data is freed.
 423          */
 424         if (buf == NULL) {
 425                 ret = -1;
 426                 free(data);
 427                 goto end;
 428         }
 429
 430         *buf = data;
 431         ret = size;
 432
 433 end:
 434         disconnect_sessiond();
 435         return ret;
 436 }
 437
 438 /*
 439  * Ask the session daemon a specific command and put the data into buf.
 440  *
 441  * Return size of data (only payload, not header) or a negative error code.
 442  */
 443 static int ask_sessiond(struct lttcomm_session_msg *lsm, void **buf)
 444 {
 445         return ask_sessiond_varlen(lsm, NULL, 0, buf);
 446 }
 447
 448 /*
 449  * Create lttng handle and return pointer.
 450  * The returned pointer will be NULL in case of malloc() error.
 451  */
 452 struct lttng_handle *lttng_create_handle(const char *session_name,
 453                 struct lttng_domain *domain)
 454 {
 455         struct lttng_handle *handle;
 456
 457         handle = malloc(sizeof(struct lttng_handle));
 458         if (handle == NULL) {
 459                 perror("malloc handle");
 460                 goto end;
 461         }
 462
 463         /* Copy session name */
 464         copy_string(handle->session_name, session_name,
 465                         sizeof(handle->session_name));
 466
 467         /* Copy lttng domain */
 468         copy_lttng_domain(&handle->domain, domain);
 469
 470 end:
 471         return handle;
 472 }
 473
 474 /*
 475  * Destroy handle by free(3) the pointer.
 476  */
 477 void lttng_destroy_handle(struct lttng_handle *handle)
 478 {
 479         if (handle) {
 480                 free(handle);
 481         }
 482 }
 483
 484 /*
 485  * Register an outside consumer.
 486  * Returns size of returned session payload data or a negative error code.
 487  */
 488 int lttng_register_consumer(struct lttng_handle *handle,
 489                 const char *socket_path)
 490 {
 491         struct lttcomm_session_msg lsm;
 492
 493         lsm.cmd_type = LTTNG_REGISTER_CONSUMER;
 494         copy_string(lsm.session.name, handle->session_name,
 495                         sizeof(lsm.session.name));
 496         copy_lttng_domain(&lsm.domain, &handle->domain);
 497
 498         copy_string(lsm.u.reg.path, socket_path, sizeof(lsm.u.reg.path));
 499
 500         return ask_sessiond(&lsm, NULL);
 501 }
 502
 503 /*
 504  *  Start tracing for all traces of the session.
 505  *  Returns size of returned session payload data or a negative error code.
 506  */
 507 int lttng_start_tracing(const char *session_name)
 508 {
 509         struct lttcomm_session_msg lsm;
 510
 511         if (session_name == NULL) {
 512                 return -1;
 513         }
 514
 515         lsm.cmd_type = LTTNG_START_TRACE;
 516
 517         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 518
 519         return ask_sessiond(&lsm, NULL);
 520 }
 521
 522 /*
 523  *  Stop tracing for all traces of the session.
 524  *  Returns size of returned session payload data or a negative error code.
 525  */
 526 int lttng_stop_tracing(const char *session_name)
 527 {
 528         struct lttcomm_session_msg lsm;
 529
 530         if (session_name == NULL) {
 531                 return -1;
 532         }
 533
 534         lsm.cmd_type = LTTNG_STOP_TRACE;
 535
 536         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 537
 538         return ask_sessiond(&lsm, NULL);
 539 }
 540
 541 /*
 542  * Add context to event and/or channel.
 543  * If event_name is NULL, the context is applied to all events of the channel.
 544  * If channel_name is NULL, a lookup of the event's channel is done.
 545  * If both are NULL, the context is applied to all events of all channels.
 546  *
 547  * Returns the size of the returned payload data or a negative error code.
 548  */
 549 int lttng_add_context(struct lttng_handle *handle,
 550                 struct lttng_event_context *ctx, const char *event_name,
 551                 const char *channel_name)
 552 {
 553         struct lttcomm_session_msg lsm;
 554
 555         /* Safety check. Both are mandatory */
 556         if (handle == NULL || ctx == NULL) {
 557                 return -1;
 558         }
 559
 560         memset(&lsm, 0, sizeof(lsm));
 561
 562         lsm.cmd_type = LTTNG_ADD_CONTEXT;
 563
 564         /* Copy channel name */
 565         copy_string(lsm.u.context.channel_name, channel_name,
 566                         sizeof(lsm.u.context.channel_name));
 567         /* Copy event name */
 568         copy_string(lsm.u.context.event_name, event_name,
 569                         sizeof(lsm.u.context.event_name));
 570
 571         copy_lttng_domain(&lsm.domain, &handle->domain);
 572
 573         memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 574
 575         copy_string(lsm.session.name, handle->session_name,
 576                         sizeof(lsm.session.name));
 577
 578         return ask_sessiond(&lsm, NULL);
 579 }
 580
 581 /*
 582  *  Enable event(s) for a channel.
 583  *  If no event name is specified, all events are enabled.
 584  *  If no channel name is specified, the default 'channel0' is used.
 585  *  Returns size of returned session payload data or a negative error code.
 586  */
 587 int lttng_enable_event(struct lttng_handle *handle,
 588                 struct lttng_event *ev, const char *channel_name)
 589 {
 590         struct lttcomm_session_msg lsm;
 591
 592         if (handle == NULL || ev == NULL) {
 593                 return -1;
 594         }
 595
 596         memset(&lsm, 0, sizeof(lsm));
 597
 598         /* If no channel name, we put the default name */
 599         if (channel_name == NULL) {
 600                 copy_string(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME,
 601                                 sizeof(lsm.u.enable.channel_name));
 602         } else {
 603                 copy_string(lsm.u.enable.channel_name, channel_name,
 604                                 sizeof(lsm.u.enable.channel_name));
 605         }
 606
 607         copy_lttng_domain(&lsm.domain, &handle->domain);
 608
 609         if (ev->name[0] != '\0') {
 610                 lsm.cmd_type = LTTNG_ENABLE_EVENT;
 611         } else {
 612                 lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
 613         }
 614         memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
 615
 616         copy_string(lsm.session.name, handle->session_name,
 617                         sizeof(lsm.session.name));
 618
 619         return ask_sessiond(&lsm, NULL);
 620 }
 621
 622 /*
 623  * set filter for an event
 624  * Return negative error value on error.
 625  * Return size of returned session payload data if OK.
 626  */
 627
 628 int lttng_set_event_filter(struct lttng_handle *handle,
 629                 const char *event_name, const char *channel_name,
 630                 const char *filter_expression)
 631 {
 632         struct lttcomm_session_msg lsm;
 633         struct filter_parser_ctx *ctx;
 634         FILE *fmem;
 635         int ret = 0;
 636
 637         /* Safety check. */
 638         if (handle == NULL) {
 639                 return -1;
 640         }
 641
 642         if (!filter_expression) {
 643                 return 0;
 644         }
 645
 646         /*
 647          * casting const to non-const, as the underlying function will
 648          * use it in read-only mode.
 649          */
 650         fmem = lttng_fmemopen((void *) filter_expression,
 651                         strlen(filter_expression), "r");
 652         if (!fmem) {
 653                 fprintf(stderr, "Error opening memory as stream\n");
 654                 return -ENOMEM;
 655         }
 656         ctx = filter_parser_ctx_alloc(fmem);
 657         if (!ctx) {
 658                 fprintf(stderr, "Error allocating parser\n");
 659                 ret = -ENOMEM;
 660                 goto alloc_error;
 661         }
 662         ret = filter_parser_ctx_append_ast(ctx);
 663         if (ret) {
 664                 fprintf(stderr, "Parse error\n");
 665                 ret = -EINVAL;
 666                 goto parse_error;
 667         }
 668         ret = filter_visitor_set_parent(ctx);
 669         if (ret) {
 670                 fprintf(stderr, "Set parent error\n");
 671                 ret = -EINVAL;
 672                 goto parse_error;
 673         }
 674         if (print_xml) {
 675                 ret = filter_visitor_print_xml(ctx, stdout, 0);
 676                 if (ret) {
 677                         fflush(stdout);
 678                         fprintf(stderr, "XML print error\n");
 679                         ret = -EINVAL;
 680                         goto parse_error;
 681                 }
 682         }
 683
 684         dbg_printf("Generating IR... ");
 685         fflush(stdout);
 686         ret = filter_visitor_ir_generate(ctx);
 687         if (ret) {
 688                 fprintf(stderr, "Generate IR error\n");
 689                 ret = -EINVAL;
 690                 goto parse_error;
 691         }
 692         dbg_printf("done\n");
 693
 694         dbg_printf("Validating IR... ");
 695         fflush(stdout);
 696         ret = filter_visitor_ir_check_binary_op_nesting(ctx);
 697         if (ret) {
 698                 ret = -EINVAL;
 699                 goto parse_error;
 700         }
 701         dbg_printf("done\n");
 702
 703         dbg_printf("Generating bytecode... ");
 704         fflush(stdout);
 705         ret = filter_visitor_bytecode_generate(ctx);
 706         if (ret) {
 707                 fprintf(stderr, "Generate bytecode error\n");
 708                 ret = -EINVAL;
 709                 goto parse_error;
 710         }
 711         dbg_printf("done\n");
 712         dbg_printf("Size of bytecode generated: %u bytes.\n",
 713                 bytecode_get_len(&ctx->bytecode->b));
 714
 715         memset(&lsm, 0, sizeof(lsm));
 716
 717         lsm.cmd_type = LTTNG_SET_FILTER;
 718
 719         /* Copy channel name */
 720         copy_string(lsm.u.filter.channel_name, channel_name,
 721                         sizeof(lsm.u.filter.channel_name));
 722         /* Copy event name */
 723         copy_string(lsm.u.filter.event_name, event_name,
 724                         sizeof(lsm.u.filter.event_name));
 725         lsm.u.filter.bytecode_len = sizeof(ctx->bytecode->b)
 726                         + bytecode_get_len(&ctx->bytecode->b);
 727
 728         copy_lttng_domain(&lsm.domain, &handle->domain);
 729
 730         copy_string(lsm.session.name, handle->session_name,
 731                         sizeof(lsm.session.name));
 732
 733         ret = ask_sessiond_varlen(&lsm, &ctx->bytecode->b,
 734                                 lsm.u.filter.bytecode_len, NULL);
 735
 736         filter_bytecode_free(ctx);
 737         filter_ir_free(ctx);
 738         filter_parser_ctx_free(ctx);
 739         if (fclose(fmem) != 0) {
 740                 perror("fclose");
 741         }
 742         return ret;
 743
 744 parse_error:
 745         filter_bytecode_free(ctx);
 746         filter_ir_free(ctx);
 747         filter_parser_ctx_free(ctx);
 748 alloc_error:
 749         if (fclose(fmem) != 0) {
 750                 perror("fclose");
 751         }
 752         return ret;
 753 }
 754
 755 /*
 756  *  Disable event(s) of a channel and domain.
 757  *  If no event name is specified, all events are disabled.
 758  *  If no channel name is specified, the default 'channel0' is used.
 759  *  Returns size of returned session payload data or a negative error code.
 760  */
 761 int lttng_disable_event(struct lttng_handle *handle, const char *name,
 762                 const char *channel_name)
 763 {
 764         struct lttcomm_session_msg lsm;
 765
 766         if (handle == NULL) {
 767                 return -1;
 768         }
 769
 770         memset(&lsm, 0, sizeof(lsm));
 771
 772         if (channel_name) {
 773                 copy_string(lsm.u.disable.channel_name, channel_name,
 774                                 sizeof(lsm.u.disable.channel_name));
 775         } else {
 776                 copy_string(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME,
 777                                 sizeof(lsm.u.disable.channel_name));
 778         }
 779
 780         copy_lttng_domain(&lsm.domain, &handle->domain);
 781
 782         if (name != NULL) {
 783                 copy_string(lsm.u.disable.name, name, sizeof(lsm.u.disable.name));
 784                 lsm.cmd_type = LTTNG_DISABLE_EVENT;
 785         } else {
 786                 lsm.cmd_type = LTTNG_DISABLE_ALL_EVENT;
 787         }
 788
 789         copy_string(lsm.session.name, handle->session_name,
 790                         sizeof(lsm.session.name));
 791
 792         return ask_sessiond(&lsm, NULL);
 793 }
 794
 795 /*
 796  *  Enable channel per domain
 797  *  Returns size of returned session payload data or a negative error code.
 798  */
 799 int lttng_enable_channel(struct lttng_handle *handle,
 800                 struct lttng_channel *chan)
 801 {
 802         struct lttcomm_session_msg lsm;
 803
 804         /*
 805          * NULL arguments are forbidden. No default values.
 806          */
 807         if (handle == NULL || chan == NULL) {
 808                 return -1;
 809         }
 810
 811         memset(&lsm, 0, sizeof(lsm));
 812
 813         memcpy(&lsm.u.channel.chan, chan, sizeof(lsm.u.channel.chan));
 814
 815         lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
 816
 817         copy_lttng_domain(&lsm.domain, &handle->domain);
 818
 819         copy_string(lsm.session.name, handle->session_name,
 820                         sizeof(lsm.session.name));
 821
 822         return ask_sessiond(&lsm, NULL);
 823 }
 824
 825 /*
 826  *  All tracing will be stopped for registered events of the channel.
 827  *  Returns size of returned session payload data or a negative error code.
 828  */
 829 int lttng_disable_channel(struct lttng_handle *handle, const char *name)
 830 {
 831         struct lttcomm_session_msg lsm;
 832
 833         /* Safety check. Both are mandatory */
 834         if (handle == NULL || name == NULL) {
 835                 return -1;
 836         }
 837
 838         memset(&lsm, 0, sizeof(lsm));
 839
 840         lsm.cmd_type = LTTNG_DISABLE_CHANNEL;
 841
 842         copy_string(lsm.u.disable.channel_name, name,
 843                         sizeof(lsm.u.disable.channel_name));
 844
 845         copy_lttng_domain(&lsm.domain, &handle->domain);
 846
 847         copy_string(lsm.session.name, handle->session_name,
 848                         sizeof(lsm.session.name));
 849
 850         return ask_sessiond(&lsm, NULL);
 851 }
 852
 853 /*
 854  *  Lists all available tracepoints of domain.
 855  *  Sets the contents of the events array.
 856  *  Returns the number of lttng_event entries in events;
 857  *  on error, returns a negative value.
 858  */
 859 int lttng_list_tracepoints(struct lttng_handle *handle,
 860                 struct lttng_event **events)
 861 {
 862         int ret;
 863         struct lttcomm_session_msg lsm;
 864
 865         if (handle == NULL) {
 866                 return -1;
 867         }
 868
 869         lsm.cmd_type = LTTNG_LIST_TRACEPOINTS;
 870         copy_lttng_domain(&lsm.domain, &handle->domain);
 871
 872         ret = ask_sessiond(&lsm, (void **) events);
 873         if (ret < 0) {
 874                 return ret;
 875         }
 876
 877         return ret / sizeof(struct lttng_event);
 878 }
 879
 880 /*
 881  *  Lists all available tracepoint fields of domain.
 882  *  Sets the contents of the event field array.
 883  *  Returns the number of lttng_event_field entries in events;
 884  *  on error, returns a negative value.
 885  */
 886 int lttng_list_tracepoint_fields(struct lttng_handle *handle,
 887                 struct lttng_event_field **fields)
 888 {
 889         int ret;
 890         struct lttcomm_session_msg lsm;
 891
 892         if (handle == NULL) {
 893                 return -1;
 894         }
 895
 896         lsm.cmd_type = LTTNG_LIST_TRACEPOINT_FIELDS;
 897         copy_lttng_domain(&lsm.domain, &handle->domain);
 898
 899         ret = ask_sessiond(&lsm, (void **) fields);
 900         if (ret < 0) {
 901                 return ret;
 902         }
 903
 904         return ret / sizeof(struct lttng_event_field);
 905 }
 906
 907 /*
 908  *  Returns a human readable string describing
 909  *  the error code (a negative value).
 910  */
 911 const char *lttng_strerror(int code)
 912 {
 913         /* lttcomm error codes range from -LTTCOMM_OK down to -LTTCOMM_NR */
 914         if (code > -LTTCOMM_OK) {
 915                 return "Ended with errors";
 916         }
 917
 918         return lttcomm_get_readable_code(code);
 919 }
 920
 921 /*
 922  *  Create a brand new session using name and path.
 923  *  Returns size of returned session payload data or a negative error code.
 924  */
 925 int lttng_create_session(const char *name, const char *path)
 926 {
 927         struct lttcomm_session_msg lsm;
 928
 929         lsm.cmd_type = LTTNG_CREATE_SESSION;
 930         copy_string(lsm.session.name, name, sizeof(lsm.session.name));
 931         copy_string(lsm.session.path, path, sizeof(lsm.session.path));
 932
 933         return ask_sessiond(&lsm, NULL);
 934 }
 935
 936 /*
 937  * Create a new tracing session using a name, URIs and a consumer enable flag.
 938  */
 939 int lttng_create_session_uri(const char *name, struct lttng_uri *ctrl_uri,
 940                 struct lttng_uri *data_uri, unsigned int enable_consumer)
 941 {
 942         struct lttcomm_session_msg lsm;
 943
 944         /* Name and ctrl_uri are mandatory */
 945         if (name == NULL || ctrl_uri == NULL) {
 946                 return -1;
 947         }
 948
 949         lsm.cmd_type = LTTNG_CREATE_SESSION_URI;
 950
 951         copy_string(lsm.session.name, name, sizeof(lsm.session.name));
 952         /* Anything bigger than zero, the consumer(s) will be enabled */
 953         lsm.u.create_uri.enable_consumer = enable_consumer;
 954         memcpy(&lsm.u.create_uri.ctrl_uri, ctrl_uri,
 955                         sizeof(lsm.u.create_uri.ctrl_uri));
 956         if (data_uri) {
 957                 /*
 958                  * The only possible scenario where data_uri is NULL is for a local
 959                  * consumer where the output is at a specified path name on the
 960                  * filesystem.
 961                  */
 962                 memcpy(&lsm.u.create_uri.data_uri, data_uri,
 963                                 sizeof(lsm.u.create_uri.data_uri));
 964         }
 965
 966         return ask_sessiond(&lsm, NULL);
 967 }
 968
 969 /*
 970  *  Destroy session using name.
 971  *  Returns size of returned session payload data or a negative error code.
 972  */
 973 int lttng_destroy_session(const char *session_name)
 974 {
 975         struct lttcomm_session_msg lsm;
 976
 977         if (session_name == NULL) {
 978                 return -1;
 979         }
 980
 981         lsm.cmd_type = LTTNG_DESTROY_SESSION;
 982
 983         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
 984
 985         return ask_sessiond(&lsm, NULL);
 986 }
 987
 988 /*
 989  *  Ask the session daemon for all available sessions.
 990  *  Sets the contents of the sessions array.
 991  *  Returns the number of lttng_session entries in sessions;
 992  *  on error, returns a negative value.
 993  */
 994 int lttng_list_sessions(struct lttng_session **sessions)
 995 {
 996         int ret;
 997         struct lttcomm_session_msg lsm;
 998
 999         lsm.cmd_type = LTTNG_LIST_SESSIONS;
1000         ret = ask_sessiond(&lsm, (void**) sessions);
1001         if (ret < 0) {
1002                 return ret;
1003         }
1004
1005         return ret / sizeof(struct lttng_session);
1006 }
1007
1008 /*
1009  *  Ask the session daemon for all available domains of a session.
1010  *  Sets the contents of the domains array.
1011  *  Returns the number of lttng_domain entries in domains;
1012  *  on error, returns a negative value.
1013  */
1014 int lttng_list_domains(const char *session_name,
1015                 struct lttng_domain **domains)
1016 {
1017         int ret;
1018         struct lttcomm_session_msg lsm;
1019
1020         if (session_name == NULL) {
1021                 return -1;
1022         }
1023
1024         lsm.cmd_type = LTTNG_LIST_DOMAINS;
1025
1026         copy_string(lsm.session.name, session_name, sizeof(lsm.session.name));
1027
1028         ret = ask_sessiond(&lsm, (void**) domains);
1029         if (ret < 0) {
1030                 return ret;
1031         }
1032
1033         return ret / sizeof(struct lttng_domain);
1034 }
1035
1036 /*
1037  *  Ask the session daemon for all available channels of a session.
1038  *  Sets the contents of the channels array.
1039  *  Returns the number of lttng_channel entries in channels;
1040  *  on error, returns a negative value.
1041  */
1042 int lttng_list_channels(struct lttng_handle *handle,
1043                 struct lttng_channel **channels)
1044 {
1045         int ret;
1046         struct lttcomm_session_msg lsm;
1047
1048         if (handle == NULL) {
1049                 return -1;
1050         }
1051
1052         lsm.cmd_type = LTTNG_LIST_CHANNELS;
1053         copy_string(lsm.session.name, handle->session_name,
1054                         sizeof(lsm.session.name));
1055
1056         copy_lttng_domain(&lsm.domain, &handle->domain);
1057
1058         ret = ask_sessiond(&lsm, (void**) channels);
1059         if (ret < 0) {
1060                 return ret;
1061         }
1062
1063         return ret / sizeof(struct lttng_channel);
1064 }
1065
1066 /*
1067  *  Ask the session daemon for all available events of a session channel.
1068  *  Sets the contents of the events array.
1069  *  Returns the number of lttng_event entries in events;
1070  *  on error, returns a negative value.
1071  */
1072 int lttng_list_events(struct lttng_handle *handle,
1073                 const char *channel_name, struct lttng_event **events)
1074 {
1075         int ret;
1076         struct lttcomm_session_msg lsm;
1077
1078         /* Safety check. An handle and channel name are mandatory */
1079         if (handle == NULL || channel_name == NULL) {
1080                 return -1;
1081         }
1082
1083         lsm.cmd_type = LTTNG_LIST_EVENTS;
1084         copy_string(lsm.session.name, handle->session_name,
1085                         sizeof(lsm.session.name));
1086         copy_string(lsm.u.list.channel_name, channel_name,
1087                         sizeof(lsm.u.list.channel_name));
1088
1089         copy_lttng_domain(&lsm.domain, &handle->domain);
1090
1091         ret = ask_sessiond(&lsm, (void**) events);
1092         if (ret < 0) {
1093                 return ret;
1094         }
1095
1096         return ret / sizeof(struct lttng_event);
1097 }
1098
1099 /*
1100  * Sets the tracing_group variable with name.
1101  * This function allocates memory pointed to by tracing_group.
1102  * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
1103  */
1104 int lttng_set_tracing_group(const char *name)
1105 {
1106         if (name == NULL) {
1107                 return -1;
1108         }
1109
1110         if (asprintf(&tracing_group, "%s", name) < 0) {
1111                 return -ENOMEM;
1112         }
1113
1114         return 0;
1115 }
1116
1117 /*
1118  * Returns size of returned session payload data or a negative error code.
1119  */
1120 int lttng_calibrate(struct lttng_handle *handle,
1121                 struct lttng_calibrate *calibrate)
1122 {
1123         struct lttcomm_session_msg lsm;
1124
1125         /* Safety check. NULL pointer are forbidden */
1126         if (handle == NULL || calibrate == NULL) {
1127                 return -1;
1128         }
1129
1130         lsm.cmd_type = LTTNG_CALIBRATE;
1131         copy_lttng_domain(&lsm.domain, &handle->domain);
1132
1133         memcpy(&lsm.u.calibrate, calibrate, sizeof(lsm.u.calibrate));
1134
1135         return ask_sessiond(&lsm, NULL);
1136 }
1137
1138 /*
1139  * Set default channel attributes.
1140  * If either or both of the arguments are null, attr content is zeroe'd.
1141  */
1142 void lttng_channel_set_default_attr(struct lttng_domain *domain,
1143                 struct lttng_channel_attr *attr)
1144 {
1145         /* Safety check */
1146         if (attr == NULL || domain == NULL) {
1147                 return;
1148         }
1149
1150         memset(attr, 0, sizeof(struct lttng_channel_attr));
1151
1152         switch (domain->type) {
1153         case LTTNG_DOMAIN_KERNEL:
1154                 attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
1155                 attr->switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
1156                 attr->read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
1157
1158                 attr->subbuf_size = DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE;
1159                 attr->num_subbuf = DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM;
1160                 attr->output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
1161                 break;
1162         case LTTNG_DOMAIN_UST:
1163 #if 0
1164         case LTTNG_DOMAIN_UST_EXEC_NAME:
1165         case LTTNG_DOMAIN_UST_PID:
1166         case LTTNG_DOMAIN_UST_PID_FOLLOW_CHILDREN:
1167 #endif
1168                 attr->overwrite = DEFAULT_CHANNEL_OVERWRITE;
1169                 attr->switch_timer_interval = DEFAULT_CHANNEL_SWITCH_TIMER;
1170                 attr->read_timer_interval = DEFAULT_CHANNEL_READ_TIMER;
1171
1172                 attr->subbuf_size = DEFAULT_UST_CHANNEL_SUBBUF_SIZE;
1173                 attr->num_subbuf = DEFAULT_UST_CHANNEL_SUBBUF_NUM;
1174                 attr->output = DEFAULT_UST_CHANNEL_OUTPUT;
1175                 break;
1176         default:
1177                 /* Default behavior: leave set to 0. */
1178                 break;
1179         }
1180 }
1181
1182 /*
1183  * Check if session daemon is alive.
1184  *
1185  * Return 1 if alive or 0 if not.
1186  * On error returns a negative value.
1187  */
1188 int lttng_session_daemon_alive(void)
1189 {
1190         int ret;
1191
1192         ret = set_session_daemon_path();
1193         if (ret < 0) {
1194                 /* Error */
1195                 return ret;
1196         }
1197
1198         if (strlen(sessiond_sock_path) == 0) {
1199                 /* No socket path set. Weird error */
1200                 return -1;
1201         }
1202
1203         ret = try_connect_sessiond(sessiond_sock_path);
1204         if (ret < 0) {
1205                 /* Not alive */
1206                 return 0;
1207         }
1208
1209         /* Is alive */
1210         return 1;
1211 }
1212
1213 /*
1214  * Set URI for a consumer for a session and domain.
1215  *
1216  * Return 0 on success, else a negative value.
1217  */
1218 int lttng_set_consumer_uri(struct lttng_handle *handle, struct lttng_uri *uri)
1219 {
1220         struct lttcomm_session_msg lsm;
1221
1222         if (handle == NULL || uri == NULL) {
1223                 return -1;
1224         }
1225
1226         lsm.cmd_type = LTTNG_SET_CONSUMER_URI;
1227
1228         copy_string(lsm.session.name, handle->session_name,
1229                         sizeof(lsm.session.name));
1230         copy_lttng_domain(&lsm.domain, &handle->domain);
1231
1232         memcpy(&lsm.u.uri, uri, sizeof(lsm.u.uri));
1233
1234         return ask_sessiond(&lsm, NULL);
1235 }
1236
1237 /*
1238  * Enable consumer for a session and domain.
1239  *
1240  * Return 0 on success, else a negative value.
1241  */
1242 int lttng_enable_consumer(struct lttng_handle *handle)
1243 {
1244         struct lttcomm_session_msg lsm;
1245
1246         if (handle == NULL) {
1247                 return -1;
1248         }
1249
1250         lsm.cmd_type = LTTNG_ENABLE_CONSUMER;
1251
1252         copy_string(lsm.session.name, handle->session_name,
1253                         sizeof(lsm.session.name));
1254         copy_lttng_domain(&lsm.domain, &handle->domain);
1255
1256         return ask_sessiond(&lsm, NULL);
1257 }
1258
1259 /*
1260  * Disable consumer for a session and domain.
1261  *
1262  * Return 0 on success, else a negative value.
1263  */
1264 int lttng_disable_consumer(struct lttng_handle *handle)
1265 {
1266         struct lttcomm_session_msg lsm;
1267
1268         if (handle == NULL) {
1269                 return -1;
1270         }
1271
1272         lsm.cmd_type = LTTNG_DISABLE_CONSUMER;
1273
1274         copy_string(lsm.session.name, handle->session_name,
1275                         sizeof(lsm.session.name));
1276         copy_lttng_domain(&lsm.domain, &handle->domain);
1277
1278         return ask_sessiond(&lsm, NULL);
1279 }
1280
1281 /*
1282  * lib constructor
1283  */
1284 static void __attribute__((constructor)) init()
1285 {
1286         /* Set default session group */
1287         lttng_set_tracing_group(DEFAULT_TRACING_GROUP);
1288 }