lttng/lttng.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 modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (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 along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <getopt.h>
  23 #include <grp.h>
  24 #include <limits.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <sys/wait.h>
  31 #include <unistd.h>
  32
  33 #include <lttng/lttng.h>
  34
  35 #include "lttng.h"
  36 #include "lttngerr.h"
  37
  38 /* Variables */
  39 static char *progname;
  40 static char *session_name;
  41 static uuid_t current_uuid;
  42 static int auto_session;
  43 static int auto_trace;
  44
  45 /* Prototypes */
  46 static int process_client_opt(void);
  47 static int process_opt_list_apps(void);
  48 static int process_opt_list_sessions(void);
  49 static int process_opt_list_traces(void);
  50 static int process_opt_create_session(void);
  51 static int process_kernel_create_trace(void);
  52 static int process_opt_kernel_event(void);
  53 static int process_kernel_start_trace(void);
  54 static int set_session_uuid(void);
  55 static void sighandler(int sig);
  56 static int set_signal_handler(void);
  57 static int validate_options(void);
  58 static char *get_cmdline_by_pid(pid_t pid);
  59 static void set_opt_session_info(void);
  60
  61 /*
  62  *  start_client
  63  *
  64  *  Process client request from the command line
  65  *  options. Every tracing action is done by the
  66  *  liblttngctl API.
  67  */
  68 static int process_client_opt(void)
  69 {
  70         int ret;
  71
  72         set_opt_session_info();
  73
  74         if (opt_list_apps) {
  75                 ret = process_opt_list_apps();
  76                 if (ret < 0) {
  77                         goto end;
  78                 }
  79                 goto error;
  80         }
  81
  82         if (opt_list_session) {
  83                 ret = process_opt_list_sessions();
  84                 if (ret < 0) {
  85                         goto end;
  86                 }
  87                 goto error;
  88         }
  89
  90         /* Session creation or auto session set on */
  91         if (auto_session || opt_create_session) {
  92                 DBG("Creating a new session");
  93                 ret = process_opt_create_session();
  94                 if (ret < 0) {
  95                         goto end;
  96                 }
  97         }
  98
  99         ret = set_session_uuid();
 100         if (ret < 0) {
 101                 ERR("Session %s not found", opt_session_name);
 102                 goto error;
 103         }
 104
 105         if (opt_destroy_session) {
 106                 ret = lttng_destroy_session(&current_uuid);
 107                 if (ret < 0) {
 108                         goto end;
 109                 }
 110                 MSG("Session %s destroyed.", opt_session_name);
 111         }
 112
 113         if (opt_list_traces) {
 114                 ret = process_opt_list_traces();
 115                 if (ret < 0) {
 116                         goto end;
 117                 }
 118         }
 119
 120         /*
 121          * Action on traces (kernel or/and userspace).
 122          */
 123
 124         if (opt_trace_kernel) {
 125                 if (auto_trace || opt_create_trace) {
 126                         DBG("Creating a kernel trace");
 127                         ret = process_kernel_create_trace();
 128                         if (ret < 0) {
 129                                 goto end;
 130                         }
 131                 }
 132
 133                 if (opt_event_list != NULL) {
 134                         ret = process_opt_kernel_event();
 135                         if (ret < 0) {
 136                                 goto end;
 137                         }
 138                 } else {
 139                         // Enable all events
 140                 }
 141
 142                 if (auto_trace || opt_start_trace) {
 143                         DBG("Starting kernel tracing");
 144                         ret = process_kernel_start_trace();
 145                         if (ret < 0) {
 146                                 goto end;
 147                         }
 148                 }
 149
 150                 if (opt_stop_trace) {
 151                         DBG("Stopping kernel tracing");
 152                         ret = lttng_kernel_stop_tracing();
 153                         if (ret < 0) {
 154                                 goto end;
 155                         }
 156                 }
 157         }
 158
 159         if (opt_trace_pid != 0) {
 160                 if (auto_trace || opt_create_trace) {
 161                         DBG("Create a userspace trace for pid %d", opt_trace_pid);
 162                         ret = lttng_ust_create_trace(opt_trace_pid);
 163                         if (ret < 0) {
 164                                 goto end;
 165                         }
 166                         MSG("Trace created successfully!");
 167                 }
 168
 169                 if (auto_trace || opt_start_trace) {
 170                         DBG("Start trace for pid %d", opt_trace_pid);
 171                         ret = lttng_ust_start_trace(opt_trace_pid);
 172                         if (ret < 0) {
 173                                 goto end;
 174                         }
 175                         MSG("Trace started successfully!");
 176                 } else if (opt_stop_trace) {
 177                         DBG("Stop trace for pid %d", opt_trace_pid);
 178                         ret = lttng_ust_stop_trace(opt_trace_pid);
 179                         if (ret < 0) {
 180                                 goto end;
 181                         }
 182                         MSG("Trace stopped successfully!");
 183                 }
 184
 185         }
 186
 187         return 0;
 188
 189 end:
 190         ERR("%s", lttng_get_readable_code(ret));
 191 error:  /* fall through */
 192         return ret;
 193 }
 194
 195 /*
 196  *  process_kernel_start_trace
 197  *
 198  *  Start a kernel trace.
 199  */
 200 static int process_kernel_start_trace(void)
 201 {
 202         int ret;
 203
 204         ret = lttng_kernel_create_stream();
 205         if (ret < 0) {
 206                 goto error;
 207         }
 208
 209         ret = lttng_kernel_start_tracing();
 210         if (ret < 0) {
 211                 goto error;
 212         }
 213
 214         MSG("Kernel tracing started");
 215
 216         return 0;
 217
 218 error:
 219         return ret;
 220 }
 221
 222 /*
 223  *  process_kernel_create_trace
 224  *
 225  *  Create a kernel trace.
 226  */
 227 static int process_kernel_create_trace(void)
 228 {
 229         int ret;
 230
 231         /* Setup kernel session */
 232         ret = lttng_kernel_create_session();
 233         if (ret < 0) {
 234                 goto error;
 235         }
 236
 237         /* Create an empty channel (with no event) */
 238         ret = lttng_kernel_create_channel();
 239         if (ret < 0) {
 240                 goto error;
 241         }
 242
 243         /* Opening metadata for session */
 244         ret = lttng_kernel_open_metadata();
 245         if (ret < 0) {
 246                 goto error;
 247         }
 248
 249         return 0;
 250
 251 error:
 252         return ret;
 253 }
 254
 255 /*
 256  *  process_kernel_event
 257  *
 258  *  Enable kernel event from the command line list given.
 259  */
 260 static int process_opt_kernel_event(void)
 261 {
 262         int ret;
 263         char *event_name;
 264
 265         event_name = strtok(opt_event_list, ",");
 266         while (event_name != NULL) {
 267                 DBG("Enabling kernel event %s", event_name);
 268                 ret = lttng_kernel_enable_event(event_name);
 269                 if (ret < 0) {
 270                         ERR("%s %s", lttng_get_readable_code(ret), event_name);
 271                 } else {
 272                         MSG("Kernel event %s enabled.", event_name);
 273                 }
 274                 /* Next event */
 275                 event_name = strtok(NULL, ",");
 276         }
 277
 278         return 0;
 279 }
 280
 281 /*
 282  *  set_opt_session_info
 283  *
 284  *  Setup session_name, current_uuid, short_str_uuid and
 285  *  long_str_uuid using the command line options.
 286  */
 287 static void set_opt_session_info(void)
 288 {
 289         if (opt_session_name != NULL) {
 290                 session_name = strndup(opt_session_name, NAME_MAX);
 291                 DBG("Session name set to %s", session_name);
 292         }
 293 }
 294
 295 /*
 296  *  set_session_uuid
 297  *
 298  *  Set current session uuid to the current flow of command(s) using the
 299  *  session_name.
 300  */
 301 static int set_session_uuid(void)
 302 {
 303         int ret, count, i, found = 0;
 304         struct lttng_session *sessions;
 305
 306         if (!uuid_is_null(current_uuid)) {
 307                 lttng_set_current_session_uuid(&current_uuid);
 308                 goto end;
 309         }
 310
 311         count = lttng_list_sessions(&sessions);
 312         if (count < 0) {
 313                 ret = count;
 314                 goto error;
 315         }
 316
 317         for (i = 0; i < count; i++) {
 318                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 319                         lttng_set_current_session_uuid(&sessions[i].uuid);
 320                         uuid_copy(current_uuid, sessions[i].uuid);
 321                         found = 1;
 322                         break;
 323                 }
 324         }
 325
 326         free(sessions);
 327
 328         if (!found) {
 329                 return -1;
 330         }
 331
 332 end:
 333         DBG("Session UUID set");
 334         return 0;
 335
 336 error:
 337         return ret;
 338 }
 339
 340 /*
 341  *  process_opt_list_traces
 342  *
 343  *  Get list of all traces for a specific session uuid.
 344  */
 345 static int process_opt_list_traces(void)
 346 {
 347         int ret, i;
 348         struct lttng_trace *traces;
 349
 350         ret = lttng_list_traces(&current_uuid, &traces);
 351         DBG("Number of traces to list %d", ret);
 352         if (ret < 0) {
 353                 goto error;
 354         }
 355
 356         /* No traces */
 357         if (ret == 0) {
 358                 MSG("No traces found.");
 359                 goto error;
 360         }
 361
 362         MSG("Userspace traces:");
 363         for (i = 0; i < ret; i++) {
 364                 if (traces[i].type == USERSPACE) {
 365                         MSG("\t%d) %s (pid: %d): %s",
 366                                         i, traces[i].name, traces[i].pid,
 367                                         get_cmdline_by_pid(traces[i].pid));
 368                 } else {
 369                         break;
 370                 }
 371         }
 372
 373         MSG("Kernel traces:");
 374         for (;i < ret; i++) {
 375                 if (traces[i].type == KERNEL) {
 376                         MSG("\t%d) %s", i, traces[i].name);
 377                 }
 378         }
 379
 380         free(traces);
 381
 382 error:
 383         return ret;
 384 }
 385
 386 /*
 387  *  process_opt_create_session
 388  *
 389  *  Create a new session using the name pass
 390  *  to the command line.
 391  */
 392 static int process_opt_create_session(void)
 393 {
 394         int ret;
 395         char name[NAME_MAX];
 396         time_t rawtime;
 397         struct tm *timeinfo;
 398
 399         /* Auto session name creation */
 400         if (opt_session_name == NULL) {
 401                 time(&rawtime);
 402                 timeinfo = localtime(&rawtime);
 403                 strftime(name, sizeof(name), "auto-%Y%m%d-%H%M%S", timeinfo);
 404                 session_name = strndup(name, sizeof(name));
 405                 DBG("Auto session name set to %s", session_name);
 406         }
 407
 408         ret = lttng_create_session(session_name);
 409         if (ret < 0) {
 410                 goto error;
 411         }
 412
 413         MSG("Session created: %s", session_name);
 414
 415 error:
 416         return ret;
 417 }
 418
 419 /*
 420  *  process_opt_list_sessions
 421  *
 422  *  Get the list of available sessions from
 423  *  the session daemon and print it to user.
 424  */
 425 static int process_opt_list_sessions(void)
 426 {
 427         int ret, count, i;
 428         struct lttng_session *sessions;
 429
 430         count = lttng_list_sessions(&sessions);
 431         DBG("Session count %d", count);
 432         if (count < 0) {
 433                 ret = count;
 434                 goto error;
 435         }
 436
 437         MSG("Available sessions (UUIDs):");
 438         for (i = 0; i < count; i++) {
 439                 MSG("    %d) %s", i+1, sessions[i].name);
 440         }
 441
 442         free(sessions);
 443         MSG("\nTo select a session, use -s, --session UUID.");
 444
 445         return 0;
 446
 447 error:
 448         return ret;
 449 }
 450
 451 /*
 452  *  process_opt_list_apps
 453  *
 454  *  Get the UST traceable pid list and print
 455  *  them to the user.
 456  */
 457 static int process_opt_list_apps(void)
 458 {
 459         int i, ret, count;
 460         pid_t *pids;
 461         char *cmdline;
 462
 463         count = lttng_ust_list_apps(&pids);
 464         if (count < 0) {
 465                 ret = count;
 466                 goto error;
 467         }
 468
 469         MSG("LTTng UST traceable application [name (pid)]:");
 470         for (i=0; i < count; i++) {
 471                 cmdline = get_cmdline_by_pid(pids[i]);
 472                 if (cmdline == NULL) {
 473                         MSG("\t(not running) (%d)", pids[i]);
 474                         continue;
 475                 }
 476                 MSG("\t%s (%d)", cmdline, pids[i]);
 477                 free(cmdline);
 478         }
 479
 480         /* Allocated by lttng_ust_list_apps() */
 481         free(pids);
 482
 483         return 0;
 484
 485 error:
 486         return ret;
 487 }
 488
 489 /*
 490  *  get_cmdline_by_pid
 491  *
 492  *  Get command line from /proc for a specific pid.
 493  *
 494  *  On success, return an allocated string pointer pointing to
 495  *  the proc cmdline.
 496  *  On error, return NULL.
 497  */
 498 static char *get_cmdline_by_pid(pid_t pid)
 499 {
 500         int ret;
 501         FILE *fp;
 502         char *cmdline = NULL;
 503         char path[24];  /* Can't go bigger than /proc/65535/cmdline */
 504
 505         snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
 506         fp = fopen(path, "r");
 507         if (fp == NULL) {
 508                 goto end;
 509         }
 510
 511         /* Caller must free() *cmdline */
 512         cmdline = malloc(PATH_MAX);
 513         ret = fread(cmdline, 1, PATH_MAX, fp);
 514         fclose(fp);
 515
 516 end:
 517         return cmdline;
 518 }
 519
 520 /*
 521  *  validate_options
 522  *
 523  *  Make sure that all options passed to the command line are compatible with
 524  *  each others.
 525  *
 526  *  On error, return -1
 527  *  On success, return 0
 528  */
 529 static int validate_options(void)
 530 {
 531         /* If listing options, jump validation */
 532         if (opt_list_apps || opt_list_session) {
 533                 goto end;
 534         }
 535         /* Conflicting command */
 536         if (opt_start_trace && opt_stop_trace) {
 537                 ERR("Can't use --start and --stop together.");
 538                 goto error;
 539         /* If no PID specified and trace_kernel is off */
 540         } else if ((opt_trace_pid == 0 && !opt_trace_kernel) &&
 541                         (opt_create_trace || opt_start_trace || opt_stop_trace || opt_destroy_trace)) {
 542                 ERR("Please specify for which tracer (-k or -p PID).");
 543                 goto error;
 544         /* List traces, we need a session name */
 545         } else if (opt_list_traces && opt_session_name == NULL) {
 546                 ERR("Can't use -t without -s, --session option.");
 547                 goto error;
 548         /* Can't set event for both kernel and userspace at the same time */
 549         } else if (opt_event_list != NULL && (opt_trace_kernel && opt_trace_pid)) {
 550                 ERR("Please don't use --event for both kernel and userspace.\nOne at a time to enable events.");
 551                 goto error;
 552         /* Don't need a trace name for kernel tracig */
 553         } else if (opt_trace_name != NULL && opt_trace_kernel) {
 554                 ERR("For action on a kernel trace, please don't specify a trace name.");
 555                 goto error;
 556         } else if (opt_destroy_trace && opt_session_name == NULL) {
 557                 ERR("Please specify a session in order to destroy a trace");
 558                 goto error;
 559         } else if (opt_create_trace || opt_destroy_trace) {
 560                 /* Both kernel and user-space are denied for these options */
 561                 if (opt_trace_pid != 0 && opt_trace_kernel) {
 562                         ERR("Kernel and user-space trace creation and destruction can't be used together.");
 563                         goto error;
 564                 /* Need a trace name for user-space tracing */
 565                 } else if (opt_trace_name == NULL && opt_trace_pid != 0) {
 566                         ERR("Please specify a trace name for user-space tracing");
 567                         goto error;
 568                 }
 569         } else if (opt_stop_trace && opt_trace_pid != 0 && opt_trace_name == NULL) {
 570                 ERR("Please specify a trace name for user-space tracing");
 571                 goto error;
 572         } else if (opt_stop_trace && opt_session_name == NULL) {
 573                 ERR("Please specify a session to stop tracing");
 574                 goto error;
 575         }
 576
 577         /* If start trace, auto start tracing */
 578         if (opt_start_trace || opt_event_list != NULL) {
 579                 DBG("Requesting auto tracing");
 580                 auto_trace = 1;
 581         }
 582
 583         /* If no session, auto create one */
 584         if (opt_session_name == NULL) {
 585                 DBG("Requesting an auto session creation");
 586                 auto_session = 1;
 587         }
 588
 589 end:
 590         return 0;
 591
 592 error:
 593         return -1;
 594 }
 595
 596 /*
 597  *  spawn_sessiond
 598  *
 599  *  Spawn a session daemon by forking and execv.
 600  */
 601 static int spawn_sessiond(char *pathname)
 602 {
 603         int ret = 0;
 604         pid_t pid;
 605
 606         MSG("Spawning session daemon");
 607         pid = fork();
 608         if (pid == 0) {
 609                 /*
 610                  * Spawn session daemon and tell
 611                  * it to signal us when ready.
 612                  */
 613                 execlp(pathname, "ltt-sessiond", "--sig-parent", "--quiet", NULL);
 614                 /* execlp only returns if error happened */
 615                 if (errno == ENOENT) {
 616                         ERR("No session daemon found. Use --sessiond-path.");
 617                 } else {
 618                         perror("execlp");
 619                 }
 620                 kill(getppid(), SIGTERM);       /* unpause parent */
 621                 exit(EXIT_FAILURE);
 622         } else if (pid > 0) {
 623                 /* Wait for ltt-sessiond to start */
 624                 pause();
 625                 goto end;
 626         } else {
 627                 perror("fork");
 628                 ret = -1;
 629                 goto end;
 630         }
 631
 632 end:
 633         return ret;
 634 }
 635
 636 /*
 637  *  check_ltt_sessiond
 638  *
 639  *  Check if the session daemon is available using
 640  *  the liblttngctl API for the check. If not, try to
 641  *  spawn a daemon.
 642  */
 643 static int check_ltt_sessiond(void)
 644 {
 645         int ret;
 646         char *pathname = NULL, *alloc_pathname = NULL;
 647
 648         ret = lttng_check_session_daemon();
 649         if (ret < 0) {
 650                 /* Try command line option path */
 651                 if (opt_sessiond_path != NULL) {
 652                         ret = access(opt_sessiond_path, F_OK | X_OK);
 653                         if (ret < 0) {
 654                                 ERR("No such file: %s", opt_sessiond_path);
 655                                 goto end;
 656                         }
 657                         pathname = opt_sessiond_path;
 658                 } else {
 659                         /* Try LTTNG_SESSIOND_PATH env variable */
 660                         pathname = getenv(LTTNG_SESSIOND_PATH_ENV);
 661                 }
 662
 663                 /* Let's rock and roll */
 664                 if (pathname == NULL) {
 665                         ret = asprintf(&alloc_pathname, "ltt-sessiond");
 666                         if (ret < 0) {
 667                                 goto end;
 668                         }
 669                         pathname = alloc_pathname;
 670                 }
 671
 672                 ret = spawn_sessiond(pathname);
 673                 free(alloc_pathname);
 674                 if (ret < 0) {
 675                         ERR("Problem occurs when starting %s", pathname);
 676                         goto end;
 677                 }
 678         }
 679
 680 end:
 681         return ret;
 682 }
 683
 684 /*
 685  *  set_signal_handler
 686  *
 687  *  Setup signal handler for SIGCHLD and SIGTERM.
 688  */
 689 static int set_signal_handler(void)
 690 {
 691         int ret = 0;
 692         struct sigaction sa;
 693         sigset_t sigset;
 694
 695         if ((ret = sigemptyset(&sigset)) < 0) {
 696                 perror("sigemptyset");
 697                 goto end;
 698         }
 699
 700         sa.sa_handler = sighandler;
 701         sa.sa_mask = sigset;
 702         sa.sa_flags = 0;
 703         if ((ret = sigaction(SIGCHLD, &sa, NULL)) < 0) {
 704                 perror("sigaction");
 705                 goto end;
 706         }
 707
 708         if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) {
 709                 perror("sigaction");
 710                 goto end;
 711         }
 712
 713 end:
 714         return ret;
 715 }
 716
 717 /*
 718  *  sighandler
 719  *
 720  *  Signal handler for the daemon
 721  */
 722 static void sighandler(int sig)
 723 {
 724         switch (sig) {
 725                 case SIGTERM:
 726                         DBG("SIGTERM catched");
 727                         clean_exit(EXIT_FAILURE);
 728                         break;
 729                 case SIGCHLD:
 730                         /* Notify is done */
 731                         DBG("SIGCHLD catched");
 732                         break;
 733                 default:
 734                         DBG("Unknown signal %d catched", sig);
 735                         break;
 736         }
 737
 738         return;
 739 }
 740
 741 /*
 742  * clean_exit
 743  */
 744 void clean_exit(int code)
 745 {
 746         DBG("Clean exit");
 747         if (session_name) {
 748                 free(session_name);
 749         }
 750
 751         exit(code);
 752 }
 753
 754 /*
 755  *  main
 756  */
 757 int main(int argc, char *argv[])
 758 {
 759         int ret;
 760
 761         progname = argv[0] ? argv[0] : "lttng";
 762
 763         /* For Mathieu Desnoyers aka Dr Tracing */
 764         if (strncmp(progname, "drtrace", 7) == 0) {
 765                 MSG("%c[%d;%dmWelcome back Dr Tracing!%c[%dm\n\n", 27,1,33,27,0);
 766         }
 767
 768         ret = parse_args(argc, (const char **) argv);
 769         if (ret < 0) {
 770                 clean_exit(EXIT_FAILURE);
 771         }
 772
 773         ret = validate_options();
 774         if (ret < 0) {
 775                 return EXIT_FAILURE;
 776         }
 777
 778         ret = set_signal_handler();
 779         if (ret < 0) {
 780                 clean_exit(ret);
 781         }
 782
 783         if (opt_tracing_group != NULL) {
 784                 DBG("Set tracing group to '%s'", opt_tracing_group);
 785                 lttng_set_tracing_group(opt_tracing_group);
 786         }
 787
 788         /* If ask for kernel tracing, need root perms */
 789         if (opt_trace_kernel) {
 790                 DBG("Kernel tracing activated");
 791                 if (getuid() != 0) {
 792                         ERR("%s must be setuid root", progname);
 793                         clean_exit(-EPERM);
 794                 }
 795         }
 796
 797         /* Check if the lttng session daemon is running.
 798          * If no, a daemon will be spawned.
 799          */
 800         if (opt_no_sessiond == 0 && (check_ltt_sessiond() < 0)) {
 801                 clean_exit(EXIT_FAILURE);
 802         }
 803
 804         ret = process_client_opt();
 805         if (ret < 0) {
 806                 clean_exit(ret);
 807         }
 808
 809         clean_exit(0);
 810
 811         return 0;
 812 }