liblttngctl/liblttngctl.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <errno.h>
  21 #include <grp.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include <lttng/lttng.h>
  28
  29 #include "liblttsessiondcomm.h"
  30 #include "lttngerr.h"
  31 #include "lttng-share.h"
  32
  33 /* Socket to session daemon for communication */
  34 static int sessiond_socket;
  35 static char sessiond_sock_path[PATH_MAX];
  36
  37 /* Communication structure to ltt-sessiond */
  38 static struct lttcomm_session_msg lsm;
  39 static struct lttcomm_lttng_msg llm;
  40
  41 /* Variables */
  42 static char *tracing_group;
  43 static int connected;
  44
  45 /*
  46  *  send_data_sessiond
  47  *
  48  *  Send lttcomm_session_msg to the session daemon.
  49  *
  50  *  On success, return 0
  51  *  On error, return error code
  52  */
  53 static int send_data_sessiond(void)
  54 {
  55         int ret;
  56
  57         if (!connected) {
  58                 ret = -ENOTCONN;
  59                 goto end;
  60         }
  61
  62         ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm));
  63
  64 end:
  65         return ret;
  66 }
  67
  68 /*
  69  *  recv_data_sessiond
  70  *
  71  *  Receive data from the sessiond socket.
  72  *
  73  *  On success, return 0
  74  *  On error, return recv() error code
  75  */
  76 static int recv_data_sessiond(void *buf, size_t len)
  77 {
  78         int ret;
  79
  80         if (!connected) {
  81                 ret = -ENOTCONN;
  82                 goto end;
  83         }
  84
  85         ret = lttcomm_recv_unix_sock(sessiond_socket, buf, len);
  86
  87 end:
  88         return ret;
  89 }
  90
  91 /*
  92  *  Check if the specified group name exist.
  93  *
  94  *  If yes return 0, else return -1.
  95  */
  96 static int check_tracing_group(const char *grp_name)
  97 {
  98         struct group *grp_tracing;      /* no free(). See getgrnam(3) */
  99         gid_t *grp_list;
 100         int grp_list_size, grp_id, i;
 101         int ret = -1;
 102
 103         /* Get GID of group 'tracing' */
 104         grp_tracing = getgrnam(grp_name);
 105         if (grp_tracing == NULL) {
 106                 /* NULL means not found also. getgrnam(3) */
 107                 if (errno != 0) {
 108                         perror("getgrnam");
 109                 }
 110                 goto end;
 111         }
 112
 113         /* Get number of supplementary group IDs */
 114         grp_list_size = getgroups(0, NULL);
 115         if (grp_list_size < 0) {
 116                 perror("getgroups");
 117                 goto end;
 118         }
 119
 120         /* Alloc group list of the right size */
 121         grp_list = malloc(grp_list_size * sizeof(gid_t));
 122         grp_id = getgroups(grp_list_size, grp_list);
 123         if (grp_id < -1) {
 124                 perror("getgroups");
 125                 goto free_list;
 126         }
 127
 128         for (i = 0; i < grp_list_size; i++) {
 129                 if (grp_list[i] == grp_tracing->gr_gid) {
 130                         ret = 0;
 131                         break;
 132                 }
 133         }
 134
 135 free_list:
 136         free(grp_list);
 137
 138 end:
 139         return ret;
 140 }
 141
 142 /*
 143  *  Set sessiond socket path by putting it in the global sessiond_sock_path
 144  *  variable.
 145  */
 146 static int set_session_daemon_path(void)
 147 {
 148         int ret;
 149
 150         /* Are we in the tracing group ? */
 151         ret = check_tracing_group(tracing_group);
 152         if (ret < 0 && getuid() != 0) {
 153                 if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK,
 154                                         getenv("HOME")) < 0) {
 155                         return -ENOMEM;
 156                 }
 157         } else {
 158                 strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK,
 159                                 sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK));
 160         }
 161
 162         return 0;
 163 }
 164
 165 /*
 166  *  Connect to the LTTng session daemon.
 167  *
 168  *  On success, return 0. On error, return -1.
 169  */
 170 static int connect_sessiond(void)
 171 {
 172         int ret;
 173
 174         ret = set_session_daemon_path();
 175         if (ret < 0) {
 176                 return ret;
 177         }
 178
 179         /* Connect to the sesssion daemon */
 180         ret = lttcomm_connect_unix_sock(sessiond_sock_path);
 181         if (ret < 0) {
 182                 return ret;
 183         }
 184
 185         sessiond_socket = ret;
 186         connected = 1;
 187
 188         return 0;
 189 }
 190
 191 /*
 192  *  Clean disconnect the session daemon.
 193  */
 194 static int disconnect_sessiond(void)
 195 {
 196         int ret = 0;
 197
 198         if (connected) {
 199                 ret = lttcomm_close_unix_sock(sessiond_socket);
 200                 sessiond_socket = 0;
 201                 connected = 0;
 202         }
 203
 204         return ret;
 205 }
 206
 207 /*
 208  *  ask_sessiond
 209  *
 210  *  Ask the session daemon a specific command and put the data into buf.
 211  *
 212  *  Return size of data (only payload, not header).
 213  */
 214 static int ask_sessiond(enum lttcomm_sessiond_command lct, void **buf)
 215 {
 216         int ret;
 217         size_t size;
 218         void *data = NULL;
 219
 220         ret = connect_sessiond();
 221         if (ret < 0) {
 222                 goto end;
 223         }
 224
 225         lsm.cmd_type = lct;
 226
 227         /* Send command to session daemon */
 228         ret = send_data_sessiond();
 229         if (ret < 0) {
 230                 goto end;
 231         }
 232
 233         /* Get header from data transmission */
 234         ret = recv_data_sessiond(&llm, sizeof(llm));
 235         if (ret < 0) {
 236                 goto end;
 237         }
 238
 239         /* Check error code if OK */
 240         if (llm.ret_code != LTTCOMM_OK) {
 241                 ret = -llm.ret_code;
 242                 goto end;
 243         }
 244
 245         size = llm.data_size;
 246         if (size == 0) {
 247                 ret = 0;
 248                 goto end;
 249         }
 250
 251         data = (void*) malloc(size);
 252
 253         /* Get payload data */
 254         ret = recv_data_sessiond(data, size);
 255         if (ret < 0) {
 256                 free(data);
 257                 goto end;
 258         }
 259
 260         *buf = data;
 261         ret = size;
 262
 263 end:
 264         disconnect_sessiond();
 265         return ret;
 266 }
 267
 268 /*
 269  *  Start tracing for all trace of the session.
 270  */
 271 int lttng_start_tracing(const char *session_name)
 272 {
 273         strncpy(lsm.session_name, session_name, NAME_MAX);
 274         return ask_sessiond(LTTNG_START_TRACE, NULL);
 275 }
 276
 277 /*
 278  *  Stop tracing for all trace of the session.
 279  */
 280 int lttng_stop_tracing(const char *session_name)
 281 {
 282         strncpy(lsm.session_name, session_name, NAME_MAX);
 283         return ask_sessiond(LTTNG_STOP_TRACE, NULL);
 284 }
 285
 286 /*
 287  *  lttng_add_context
 288  */
 289 int lttng_add_context(struct lttng_domain *domain,
 290                 struct lttng_event_context *ctx, const char *event_name,
 291                 const char *channel_name)
 292 {
 293         int ret;
 294
 295         if (channel_name != NULL) {
 296                 strncpy(lsm.u.context.channel_name, channel_name, NAME_MAX);
 297         }
 298
 299         if (event_name != NULL) {
 300                 strncpy(lsm.u.context.event_name, event_name, NAME_MAX);
 301         }
 302
 303         memcpy(&lsm.u.context.ctx, ctx, sizeof(struct lttng_event_context));
 304
 305         switch (domain->type) {
 306         case LTTNG_DOMAIN_KERNEL:
 307                 ret = ask_sessiond(LTTNG_KERNEL_ADD_CONTEXT, NULL);
 308                 break;
 309         case LTTNG_DOMAIN_UST:
 310                 ret = LTTCOMM_NOT_IMPLEMENTED;
 311                 break;
 312         default:
 313                 ret = LTTCOMM_UNKNOWN_DOMAIN;
 314                 break;
 315         };
 316
 317         return ret;
 318 }
 319
 320 /*
 321  *  lttng_enable_event
 322  */
 323 int lttng_enable_event(struct lttng_domain *domain,
 324                 struct lttng_event *ev, const char *channel_name)
 325 {
 326         int ret;
 327
 328         if (channel_name == NULL) {
 329                 strncpy(lsm.u.enable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
 330         } else {
 331                 strncpy(lsm.u.enable.channel_name, channel_name, NAME_MAX);
 332         }
 333
 334         switch (domain->type) {
 335                 case LTTNG_DOMAIN_KERNEL:
 336                         if (ev == NULL) {
 337                                 ret = ask_sessiond(LTTNG_KERNEL_ENABLE_ALL_EVENT, NULL);
 338                         } else {
 339                                 memcpy(&lsm.u.enable.event, ev, sizeof(struct lttng_event));
 340                                 ret = ask_sessiond(LTTNG_KERNEL_ENABLE_EVENT, NULL);
 341                         }
 342                         break;
 343                 case LTTNG_DOMAIN_UST:
 344                         ret = LTTCOMM_NOT_IMPLEMENTED;
 345                         break;
 346                 default:
 347                         ret = LTTCOMM_UNKNOWN_DOMAIN;
 348                         break;
 349         };
 350
 351         return ret;
 352 }
 353
 354 /*
 355  * Disable an event in the kernel tracer.
 356  */
 357 int lttng_disable_event(struct lttng_domain *domain, const char *name,
 358                 const char *channel_name)
 359 {
 360         int ret;
 361
 362         if (channel_name == NULL) {
 363                 strncpy(lsm.u.disable.channel_name, DEFAULT_CHANNEL_NAME, NAME_MAX);
 364         } else {
 365                 strncpy(lsm.u.disable.channel_name, channel_name, NAME_MAX);
 366         }
 367
 368         switch (domain->type) {
 369                 case LTTNG_DOMAIN_KERNEL:
 370                         if (name == NULL) {
 371                                 ret = ask_sessiond(LTTNG_KERNEL_DISABLE_ALL_EVENT, NULL);
 372                         } else {
 373                                 strncpy(lsm.u.disable.name, name, NAME_MAX);
 374                                 ret = ask_sessiond(LTTNG_KERNEL_DISABLE_EVENT, NULL);
 375                         }
 376                         break;
 377                 case LTTNG_DOMAIN_UST:
 378                         ret = LTTCOMM_NOT_IMPLEMENTED;
 379                         break;
 380                 default:
 381                         ret = LTTCOMM_UNKNOWN_DOMAIN;
 382                         break;
 383         };
 384
 385         return ret;
 386 }
 387
 388 /*
 389  * Enable recording for a channel for the kernel tracer.
 390  */
 391 int lttng_enable_channel(struct lttng_domain *domain,
 392                 struct lttng_channel *chan)
 393 {
 394         int ret;
 395
 396         memcpy(&lsm.u.channel.chan, chan, sizeof(struct lttng_channel));
 397
 398         switch (domain->type) {
 399                 case LTTNG_DOMAIN_KERNEL:
 400                         ret = ask_sessiond(LTTNG_KERNEL_ENABLE_CHANNEL, NULL);
 401                         break;
 402                 case LTTNG_DOMAIN_UST:
 403                         ret = LTTCOMM_NOT_IMPLEMENTED;
 404                         break;
 405                 default:
 406                         ret = LTTCOMM_UNKNOWN_DOMAIN;
 407                         break;
 408         };
 409
 410         return ret;
 411 }
 412
 413 /*
 414  * Disable recording for the channel for the kernel tracer.
 415  */
 416 int lttng_disable_channel(struct lttng_domain *domain, const char *name)
 417 {
 418         int ret;
 419
 420         strncpy(lsm.u.disable.channel_name, name, NAME_MAX);
 421
 422         switch (domain->type) {
 423                 case LTTNG_DOMAIN_KERNEL:
 424                         ret = ask_sessiond(LTTNG_KERNEL_DISABLE_CHANNEL, NULL);
 425                         break;
 426                 case LTTNG_DOMAIN_UST:
 427                         ret = LTTCOMM_NOT_IMPLEMENTED;
 428                         break;
 429                 default:
 430                         ret = LTTCOMM_UNKNOWN_DOMAIN;
 431                         break;
 432         };
 433
 434         return ret;
 435 }
 436
 437 /*
 438  * List all available events in the kernel.
 439  *
 440  * Return the size (bytes) of the list and set the event_list array.
 441  * On error, return negative value.
 442  */
 443 int lttng_list_events(struct lttng_domain *domain, char **event_list)
 444 {
 445         int ret;
 446
 447         switch (domain->type) {
 448                 case LTTNG_DOMAIN_KERNEL:
 449                         ret = ask_sessiond(LTTNG_KERNEL_LIST_EVENTS, (void **) event_list);
 450                         break;
 451                 case LTTNG_DOMAIN_UST:
 452                         ret = LTTCOMM_NOT_IMPLEMENTED;
 453                         break;
 454                 default:
 455                         ret = LTTCOMM_UNKNOWN_DOMAIN;
 456                         break;
 457         };
 458
 459         return ret;
 460 }
 461
 462 /*
 463  *  Return a human readable string of code
 464  */
 465 const char *lttng_get_readable_code(int code)
 466 {
 467         if (code > -LTTCOMM_OK) {
 468                 return "Ended with errors";
 469         }
 470
 471         return lttcomm_get_readable_code(code);
 472 }
 473
 474 /*
 475  *  Create a brand new session using name.
 476  */
 477 int lttng_create_session(const char *name, const char *path)
 478 {
 479         strncpy(lsm.session_name, name, NAME_MAX);
 480         strncpy(lsm.path, path, PATH_MAX);
 481         return ask_sessiond(LTTNG_CREATE_SESSION, NULL);
 482 }
 483
 484 /*
 485  *  Destroy session using name.
 486  */
 487 int lttng_destroy_session(const char *name)
 488 {
 489         strncpy(lsm.session_name, name, NAME_MAX);
 490         return ask_sessiond(LTTNG_DESTROY_SESSION, NULL);
 491 }
 492
 493 /*
 494  *  Ask the session daemon for all available sessions.
 495  *
 496  *  Return number of session.
 497  *  On error, return negative value.
 498  */
 499 int lttng_list_sessions(struct lttng_session **sessions)
 500 {
 501         int ret;
 502
 503         ret = ask_sessiond(LTTNG_LIST_SESSIONS, (void**) sessions);
 504         if (ret < 0) {
 505                 return ret;
 506         }
 507
 508         return ret / sizeof(struct lttng_session);
 509 }
 510
 511 /*
 512  * Set session name for the current lsm.
 513  */
 514 void lttng_set_session_name(const char *name)
 515 {
 516         strncpy(lsm.session_name, name, NAME_MAX);
 517 }
 518
 519 /*
 520  *  lttng_set_tracing_group
 521  *
 522  *  Set tracing group variable with name. This function
 523  *  allocate memory pointed by tracing_group.
 524  */
 525 int lttng_set_tracing_group(const char *name)
 526 {
 527         if (asprintf(&tracing_group, "%s", name) < 0) {
 528                 return -ENOMEM;
 529         }
 530
 531         return 0;
 532 }
 533
 534 /*
 535  *  lttng_check_session_daemon
 536  *
 537  *  Yes, return 1
 538  *  No, return 0
 539  *  Error, return negative value
 540  */
 541 int lttng_session_daemon_alive(void)
 542 {
 543         int ret;
 544
 545         ret = set_session_daemon_path();
 546         if (ret < 0) {
 547                 /* Error */
 548                 return ret;
 549         }
 550
 551         /* If socket exist, we consider the daemon started */
 552         ret = access(sessiond_sock_path, F_OK);
 553         if (ret < 0) {
 554                 /* Not alive */
 555                 return 0;
 556         }
 557
 558         /* Is alive */
 559         return 1;
 560 }
 561
 562 /*
 563  * lib constructor
 564  */
 565 static void __attribute__((constructor)) init()
 566 {
 567         /* Set default session group */
 568         lttng_set_tracing_group(LTTNG_DEFAULT_TRACING_GROUP);
 569 }