src/bin/lttng/commands/view.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <popt.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16
  17 #include "../command.h"
  18
  19 static char *opt_session_name;
  20 static char *opt_viewer;
  21 static char *opt_trace_path;
  22 static const char *babeltrace_bin = CONFIG_BABELTRACE_BIN;
  23 static const char *babeltrace2_bin = CONFIG_BABELTRACE2_BIN;
  24
  25 #ifdef LTTNG_EMBED_HELP
  26 static const char help_msg[] =
  27 #include <lttng-view.1.h>
  28 ;
  29 #endif
  30
  31 enum {
  32         OPT_HELP = 1,
  33         OPT_LIST_OPTIONS,
  34 };
  35
  36 static struct poptOption long_options[] = {
  37         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  38         {"help",        'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  39         {"list-options", 0,  POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  40         {"viewer",      'e', POPT_ARG_STRING, &opt_viewer, 0, 0, 0},
  41         {"trace-path",  't', POPT_ARG_STRING, &opt_trace_path, 0, 0, 0},
  42         {0, 0, 0, 0, 0, 0, 0}
  43 };
  44
  45 /*
  46  * This is needed for each viewer since we are using execvp().
  47  */
  48 static const char *babeltrace_opts[] = { "babeltrace" };
  49 static const char *babeltrace2_opts[] = { "babeltrace2" };
  50
  51 /*
  52  * Type is also use as the index in the viewers array. So please, make sure
  53  * your enum value is in the right order in the array below.
  54  */
  55 enum viewer_type {
  56         VIEWER_BABELTRACE    = 0,
  57         VIEWER_BABELTRACE2   = 1,
  58         VIEWER_USER_DEFINED  = 2,
  59 };
  60
  61 static const struct viewer {
  62         const char *exec_name;
  63         enum viewer_type type;
  64 } viewers[] = {
  65         { "babeltrace", VIEWER_BABELTRACE },
  66         { "babeltrace2", VIEWER_BABELTRACE2 },
  67         { NULL, VIEWER_USER_DEFINED },
  68 };
  69
  70 /* Is the session we are trying to view is in live mode. */
  71 static int session_live_mode;
  72
  73 static const struct viewer *parse_options(void)
  74 {
  75         if (opt_viewer == NULL) {
  76                 /* Default is babeltrace */
  77                 return &(viewers[VIEWER_BABELTRACE2]);
  78         }
  79
  80         return &(viewers[VIEWER_USER_DEFINED]);
  81 }
  82
  83 /*
  84  * Alloc an array of string pointer from a simple string having all options
  85  * seperated by spaces. Also adds the trace path to the arguments.
  86  *
  87  * The returning pointer is ready to be passed to execvp().
  88  */
  89 static char **alloc_argv_from_user_opts(char *opts, const char *trace_path)
  90 {
  91         int i = 0, ignore_space = 0;
  92         unsigned int num_opts = 1;
  93         char **argv, *token = opts;
  94
  95         /* Count number of arguments. */
  96         do {
  97                 if (*token == ' ') {
  98                         /* Use to ignore consecutive spaces */
  99                         if (!ignore_space) {
 100                                 num_opts++;
 101                         }
 102                         ignore_space = 1;
 103                 } else {
 104                         ignore_space = 0;
 105                 }
 106                 token++;
 107         } while (*token != '\0');
 108
 109         /* Add two here for the NULL terminating element and trace path */
 110         argv = zmalloc(sizeof(char *) * (num_opts + 2));
 111         if (argv == NULL) {
 112                 goto error;
 113         }
 114
 115         token = strtok(opts, " ");
 116         while (token != NULL) {
 117                 argv[i] = strdup(token);
 118                 if (argv[i] == NULL) {
 119                         goto error;
 120                 }
 121                 token = strtok(NULL, " ");
 122                 i++;
 123         }
 124
 125         argv[num_opts] = (char *) trace_path;
 126         argv[num_opts + 1] = NULL;
 127
 128         return argv;
 129
 130 error:
 131         if (argv) {
 132                 for (i = 0; i < num_opts + 2; i++) {
 133                         free(argv[i]);
 134                 }
 135                 free(argv);
 136         }
 137
 138         return NULL;
 139 }
 140
 141 /*
 142  * Alloc an array of string pointer from an array of strings. It also adds
 143  * the trace path to the argv.
 144  *
 145  * The returning pointer is ready to be passed to execvp().
 146  */
 147 static char **alloc_argv_from_local_opts(const char **opts, size_t opts_len,
 148                 const char *trace_path)
 149 {
 150         char **argv;
 151         size_t size, mem_len;
 152
 153         /* Add one for the NULL terminating element. */
 154         mem_len = opts_len + 1;
 155         if (session_live_mode) {
 156                 /* Add 3 option for the live mode being "-i lttng-live URL". */
 157                 mem_len += 3;
 158         } else {
 159                 /* Add option for the trace path. */
 160                 mem_len += 1;
 161         }
 162
 163         size = sizeof(char *) * mem_len;
 164
 165         /* Add two here for the trace_path and the NULL terminating element. */
 166         argv = zmalloc(size);
 167         if (argv == NULL) {
 168                 goto error;
 169         }
 170
 171         memcpy(argv, opts, sizeof(char *) * opts_len);
 172
 173         if (session_live_mode) {
 174                 argv[opts_len] = (char *) "-i";
 175                 argv[opts_len + 1] = (char *) "lttng-live";
 176                 argv[opts_len + 2] = (char *) trace_path;
 177                 argv[opts_len + 3] = NULL;
 178         } else {
 179                 argv[opts_len] = (char *) trace_path;
 180                 argv[opts_len + 1] = NULL;
 181         }
 182
 183 error:
 184         return argv;
 185 }
 186
 187 /*
 188  * Spawn viewer with the trace directory path.
 189  */
 190 static int spawn_viewer(const char *trace_path)
 191 {
 192         int ret = 0;
 193         struct stat status;
 194         const char *viewer_bin = NULL;
 195         const struct viewer *viewer;
 196         char **argv = NULL;
 197
 198         /* Check for --viewer options */
 199         viewer = parse_options();
 200         if (viewer == NULL) {
 201                 ret = CMD_ERROR;
 202                 goto error;
 203         }
 204
 205 retry_viewer:
 206         switch (viewer->type) {
 207         case VIEWER_BABELTRACE2:
 208                 if (stat(babeltrace2_bin, &status) == 0) {
 209                         viewer_bin = babeltrace2_bin;
 210                 } else {
 211                         viewer_bin = viewer->exec_name;
 212                 }
 213                 argv = alloc_argv_from_local_opts(babeltrace2_opts,
 214                                 ARRAY_SIZE(babeltrace2_opts), trace_path);
 215                 break;
 216         case VIEWER_BABELTRACE:
 217                 if (stat(babeltrace_bin, &status) == 0) {
 218                         viewer_bin = babeltrace_bin;
 219                 } else {
 220                         viewer_bin = viewer->exec_name;
 221                 }
 222                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 223                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 224                 break;
 225         case VIEWER_USER_DEFINED:
 226                 argv = alloc_argv_from_user_opts(opt_viewer, trace_path);
 227                 if (argv) {
 228                         viewer_bin = argv[0];
 229                 }
 230                 break;
 231         default:
 232                 viewer_bin = viewers[VIEWER_BABELTRACE].exec_name;
 233                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 234                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 235                 break;
 236         }
 237
 238         if (argv == NULL || !viewer_bin) {
 239                 ret = CMD_FATAL;
 240                 goto error;
 241         }
 242
 243         DBG("Using %s viewer", viewer_bin);
 244
 245         ret = execvp(viewer_bin, argv);
 246         if (ret) {
 247                 if (errno == ENOENT && viewer->exec_name) {
 248                         if (viewer->type == VIEWER_BABELTRACE2) {
 249                                 /* Fallback to legacy babeltrace. */
 250                                 DBG("babeltrace2 not installed on the system, falling back to babeltrace 1.x");
 251                                 viewer = &viewers[VIEWER_BABELTRACE];
 252                                 free(argv);
 253                                 argv = NULL;
 254                                 goto retry_viewer;
 255                         } else {
 256                                 ERR("Viewer \"%s\" not found on the system",
 257                                                 viewer_bin);
 258                         }
 259                 } else {
 260                         PERROR("Failed to launch \"%s\" viewer", viewer_bin);
 261                 }
 262                 ret = CMD_FATAL;
 263                 goto error;
 264         }
 265
 266 error:
 267         free(argv);
 268         return ret;
 269 }
 270
 271 /*
 272  * Build the live path we need for the lttng live view.
 273  */
 274 static char *build_live_path(char *session_name)
 275 {
 276         int ret;
 277         char *path = NULL;
 278         char hostname[HOST_NAME_MAX];
 279
 280         ret = gethostname(hostname, sizeof(hostname));
 281         if (ret < 0) {
 282                 PERROR("gethostname");
 283                 goto error;
 284         }
 285
 286         ret = asprintf(&path, "net://localhost/host/%s/%s", hostname,
 287                         session_name);
 288         if (ret < 0) {
 289                 PERROR("asprintf live path");
 290                 goto error;
 291         }
 292
 293 error:
 294         return path;
 295 }
 296
 297 /*
 298  * Exec viewer if found and use session name path.
 299  */
 300 static int view_trace(void)
 301 {
 302         int ret;
 303         char *session_name, *trace_path = NULL;
 304         struct lttng_session *sessions = NULL;
 305         bool free_trace_path = false;
 306
 307         /*
 308          * Safety net. If lttng is suid at some point for *any* useless reasons,
 309          * this prevent any bad execution of binaries.
 310          */
 311         if (getuid() != 0) {
 312                 if (getuid() != geteuid()) {
 313                         ERR("UID does not match effective UID.");
 314                         ret = CMD_ERROR;
 315                         goto error;
 316                 } else if (getgid() != getegid()) {
 317                         ERR("GID does not match effective GID.");
 318                         ret = CMD_ERROR;
 319                         goto error;
 320                 }
 321         }
 322
 323         /* User define trace path override the session name */
 324         if (opt_trace_path) {
 325                 session_name = NULL;
 326         } else if(opt_session_name == NULL) {
 327                 session_name = get_session_name();
 328                 if (session_name == NULL) {
 329                         ret = CMD_ERROR;
 330                         goto error;
 331                 }
 332         } else {
 333                 session_name = opt_session_name;
 334         }
 335
 336         DBG("Viewing trace for session %s", session_name);
 337
 338         if (session_name) {
 339                 int i, count, found = 0;
 340
 341                 /* Getting all sessions */
 342                 count = lttng_list_sessions(&sessions);
 343                 if (count < 0) {
 344                         ERR("Unable to list sessions. Session name %s not found.",
 345                                         session_name);
 346                         MSG("Is there a session daemon running?");
 347                         ret = CMD_ERROR;
 348                         goto free_error;
 349                 }
 350
 351                 /* Find our session listed by the session daemon */
 352                 for (i = 0; i < count; i++) {
 353                         if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 354                                 found = 1;
 355                                 break;
 356                         }
 357                 }
 358
 359                 if (!found) {
 360                         MSG("Session name %s not found", session_name);
 361                         ret = CMD_ERROR;
 362                         goto free_sessions;
 363                 }
 364
 365                 session_live_mode = sessions[i].live_timer_interval;
 366
 367                 DBG("Session live mode set to %d", session_live_mode);
 368
 369                 if (sessions[i].enabled && !session_live_mode) {
 370                         WARN("Session %s is running. Please stop it before reading it.",
 371                                         session_name);
 372                         ret = CMD_ERROR;
 373                         goto free_sessions;
 374                 }
 375
 376                 /* If the timer interval is set we are in live mode. */
 377                 if (session_live_mode) {
 378                         trace_path = build_live_path(session_name);
 379                         if (!trace_path) {
 380                                 ret = CMD_ERROR;
 381                                 goto free_sessions;
 382                         }
 383                         free_trace_path = true;
 384                 } else {
 385                         /* Get file system session path. */
 386                         trace_path = sessions[i].path;
 387                 }
 388         } else {
 389                 trace_path = opt_trace_path;
 390         }
 391
 392         MSG("Trace directory: %s\n", trace_path);
 393
 394         ret = spawn_viewer(trace_path);
 395         if (ret < 0) {
 396                 /* Don't set ret so lttng can interpret the sessiond error. */
 397                 goto free_sessions;
 398         }
 399
 400 free_sessions:
 401         if (session_live_mode && free_trace_path) {
 402                 free(trace_path);
 403         }
 404         free(sessions);
 405 free_error:
 406         if (opt_session_name == NULL) {
 407                 free(session_name);
 408         }
 409 error:
 410         return ret;
 411 }
 412
 413 /*
 414  * The 'view <options>' first level command
 415  */
 416 int cmd_view(int argc, const char **argv)
 417 {
 418         int opt, ret = CMD_SUCCESS;
 419         static poptContext pc;
 420         const char *leftover = NULL;
 421
 422         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 423         poptReadDefaultConfig(pc, 0);
 424
 425         if (lttng_opt_mi) {
 426                 WARN("mi does not apply to view command");
 427         }
 428
 429         while ((opt = poptGetNextOpt(pc)) != -1) {
 430                 switch (opt) {
 431                 case OPT_HELP:
 432                         SHOW_HELP();
 433                         goto end;
 434                 case OPT_LIST_OPTIONS:
 435                         list_cmd_options(stdout, long_options);
 436                         goto end;
 437                 default:
 438                         ret = CMD_UNDEFINED;
 439                         goto end;
 440                 }
 441         }
 442
 443         opt_session_name = (char*) poptGetArg(pc);
 444
 445         leftover = poptGetArg(pc);
 446         if (leftover) {
 447                 ERR("Unknown argument: %s", leftover);
 448                 ret = CMD_ERROR;
 449                 goto end;
 450         }
 451
 452         ret = view_trace();
 453
 454 end:
 455         poptFreeContext(pc);
 456         return ret;
 457 }