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 /*
  62  * NOTE: "lttv" is a shell command and it's not working for exec() family
  63  * functions so we might think of removing this wrapper or using bash.
  64  */
  65 static const struct viewers {
  66         const char *exec_name;
  67         enum viewer_type type;
  68 } viewers[] = {
  69         { "babeltrace", VIEWER_BABELTRACE },
  70         { "babeltrace2", VIEWER_BABELTRACE2 },
  71         { NULL, VIEWER_USER_DEFINED },
  72 };
  73
  74 /* Is the session we are trying to view is in live mode. */
  75 static int session_live_mode;
  76
  77 static const struct viewers *parse_options(void)
  78 {
  79         if (opt_viewer == NULL) {
  80                 /* Default is babeltrace */
  81                 return &(viewers[VIEWER_BABELTRACE2]);
  82         }
  83
  84         /*
  85          * This means that if -e, --viewers is used, we just override everything
  86          * with it. For supported viewers like lttv, we could simply detect if "-t"
  87          * is passed and if not, add the trace directory to it.
  88          */
  89         return &(viewers[VIEWER_USER_DEFINED]);
  90 }
  91
  92 /*
  93  * Alloc an array of string pointer from a simple string having all options
  94  * seperated by spaces. Also adds the trace path to the arguments.
  95  *
  96  * The returning pointer is ready to be passed to execvp().
  97  */
  98 static char **alloc_argv_from_user_opts(char *opts, const char *trace_path)
  99 {
 100         int i = 0, ignore_space = 0;
 101         unsigned int num_opts = 1;
 102         char **argv, *token = opts;
 103
 104         /* Count number of arguments. */
 105         do {
 106                 if (*token == ' ') {
 107                         /* Use to ignore consecutive spaces */
 108                         if (!ignore_space) {
 109                                 num_opts++;
 110                         }
 111                         ignore_space = 1;
 112                 } else {
 113                         ignore_space = 0;
 114                 }
 115                 token++;
 116         } while (*token != '\0');
 117
 118         /* Add two here for the NULL terminating element and trace path */
 119         argv = zmalloc(sizeof(char *) * (num_opts + 2));
 120         if (argv == NULL) {
 121                 goto error;
 122         }
 123
 124         token = strtok(opts, " ");
 125         while (token != NULL) {
 126                 argv[i] = strdup(token);
 127                 if (argv[i] == NULL) {
 128                         goto error;
 129                 }
 130                 token = strtok(NULL, " ");
 131                 i++;
 132         }
 133
 134         argv[num_opts] = (char *) trace_path;
 135         argv[num_opts + 1] = NULL;
 136
 137         return argv;
 138
 139 error:
 140         if (argv) {
 141                 for (i = 0; i < num_opts + 2; i++) {
 142                         free(argv[i]);
 143                 }
 144                 free(argv);
 145         }
 146
 147         return NULL;
 148 }
 149
 150 /*
 151  * Alloc an array of string pointer from an array of strings. It also adds
 152  * the trace path to the argv.
 153  *
 154  * The returning pointer is ready to be passed to execvp().
 155  */
 156 static char **alloc_argv_from_local_opts(const char **opts, size_t opts_len,
 157                 const char *trace_path)
 158 {
 159         char **argv;
 160         size_t size, mem_len;
 161
 162         /* Add one for the NULL terminating element. */
 163         mem_len = opts_len + 1;
 164         if (session_live_mode) {
 165                 /* Add 3 option for the live mode being "-i lttng-live URL". */
 166                 mem_len += 3;
 167         } else {
 168                 /* Add option for the trace path. */
 169                 mem_len += 1;
 170         }
 171
 172         size = sizeof(char *) * mem_len;
 173
 174         /* Add two here for the trace_path and the NULL terminating element. */
 175         argv = zmalloc(size);
 176         if (argv == NULL) {
 177                 goto error;
 178         }
 179
 180         memcpy(argv, opts, sizeof(char *) * opts_len);
 181
 182         if (session_live_mode) {
 183                 argv[opts_len] = "-i";
 184                 argv[opts_len + 1] = "lttng-live";
 185                 argv[opts_len + 2] = (char *) trace_path;
 186                 argv[opts_len + 3] = NULL;
 187         } else {
 188                 argv[opts_len] = (char *) trace_path;
 189                 argv[opts_len + 1] = NULL;
 190         }
 191
 192 error:
 193         return argv;
 194 }
 195
 196 /*
 197  * Spawn viewer with the trace directory path.
 198  */
 199 static int spawn_viewer(const char *trace_path)
 200 {
 201         int ret = 0;
 202         struct stat status;
 203         const char *viewer_bin = NULL;
 204         const struct viewers *viewer;
 205         char **argv = NULL;
 206
 207         /* Check for --viewer options */
 208         viewer = parse_options();
 209         if (viewer == NULL) {
 210                 ret = CMD_ERROR;
 211                 goto error;
 212         }
 213
 214 retry_viewer:
 215         switch (viewer->type) {
 216         case VIEWER_BABELTRACE2:
 217                 if (stat(babeltrace2_bin, &status) == 0) {
 218                         viewer_bin = babeltrace2_bin;
 219                 } else {
 220                         viewer_bin = viewer->exec_name;
 221                 }
 222                 argv = alloc_argv_from_local_opts(babeltrace2_opts,
 223                                 ARRAY_SIZE(babeltrace2_opts), trace_path);
 224                 break;
 225         case VIEWER_BABELTRACE:
 226                 if (stat(babeltrace_bin, &status) == 0) {
 227                         viewer_bin = babeltrace_bin;
 228                 } else {
 229                         viewer_bin = viewer->exec_name;
 230                 }
 231                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 232                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 233                 break;
 234         case VIEWER_USER_DEFINED:
 235                 argv = alloc_argv_from_user_opts(opt_viewer, trace_path);
 236                 if (argv) {
 237                         viewer_bin = argv[0];
 238                 }
 239                 break;
 240         default:
 241                 viewer_bin = viewers[VIEWER_BABELTRACE].exec_name;
 242                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 243                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 244                 break;
 245         }
 246
 247         if (argv == NULL || !viewer_bin) {
 248                 ret = CMD_FATAL;
 249                 goto error;
 250         }
 251
 252         DBG("Using %s viewer", viewer_bin);
 253
 254         ret = execvp(viewer_bin, argv);
 255         if (ret) {
 256                 if (errno == ENOENT && viewer->exec_name) {
 257                         if (viewer->type == VIEWER_BABELTRACE2) {
 258                                 /* Fallback to legacy babeltrace. */
 259                                 DBG("babeltrace2 not installed on the system, falling back to babeltrace 1.x");
 260                                 viewer = &viewers[VIEWER_BABELTRACE];
 261                                 free(argv);
 262                                 argv = NULL;
 263                                 goto retry_viewer;
 264                         } else {
 265                                 ERR("Viewer \"%s\" not found on the system",
 266                                                 viewer_bin);
 267                         }
 268                 } else {
 269                         PERROR("Failed to launch \"%s\" viewer", viewer_bin);
 270                 }
 271                 ret = CMD_FATAL;
 272                 goto error;
 273         }
 274
 275 error:
 276         free(argv);
 277         return ret;
 278 }
 279
 280 /*
 281  * Build the live path we need for the lttng live view.
 282  */
 283 static char *build_live_path(char *session_name)
 284 {
 285         int ret;
 286         char *path = NULL;
 287         char hostname[HOST_NAME_MAX];
 288
 289         ret = gethostname(hostname, sizeof(hostname));
 290         if (ret < 0) {
 291                 PERROR("gethostname");
 292                 goto error;
 293         }
 294
 295         ret = asprintf(&path, "net://localhost/host/%s/%s", hostname,
 296                         session_name);
 297         if (ret < 0) {
 298                 PERROR("asprintf live path");
 299                 goto error;
 300         }
 301
 302 error:
 303         return path;
 304 }
 305
 306 /*
 307  * Exec viewer if found and use session name path.
 308  */
 309 static int view_trace(void)
 310 {
 311         int ret;
 312         char *session_name, *trace_path = NULL;
 313         struct lttng_session *sessions = NULL;
 314         bool free_trace_path = false;
 315
 316         /*
 317          * Safety net. If lttng is suid at some point for *any* useless reasons,
 318          * this prevent any bad execution of binaries.
 319          */
 320         if (getuid() != 0) {
 321                 if (getuid() != geteuid()) {
 322                         ERR("UID does not match effective UID.");
 323                         ret = CMD_ERROR;
 324                         goto error;
 325                 } else if (getgid() != getegid()) {
 326                         ERR("GID does not match effective GID.");
 327                         ret = CMD_ERROR;
 328                         goto error;
 329                 }
 330         }
 331
 332         /* User define trace path override the session name */
 333         if (opt_trace_path) {
 334                 session_name = NULL;
 335         } else if(opt_session_name == NULL) {
 336                 session_name = get_session_name();
 337                 if (session_name == NULL) {
 338                         ret = CMD_ERROR;
 339                         goto error;
 340                 }
 341         } else {
 342                 session_name = opt_session_name;
 343         }
 344
 345         DBG("Viewing trace for session %s", session_name);
 346
 347         if (session_name) {
 348                 int i, count, found = 0;
 349
 350                 /* Getting all sessions */
 351                 count = lttng_list_sessions(&sessions);
 352                 if (count < 0) {
 353                         ERR("Unable to list sessions. Session name %s not found.",
 354                                         session_name);
 355                         MSG("Is there a session daemon running?");
 356                         ret = CMD_ERROR;
 357                         goto free_error;
 358                 }
 359
 360                 /* Find our session listed by the session daemon */
 361                 for (i = 0; i < count; i++) {
 362                         if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 363                                 found = 1;
 364                                 break;
 365                         }
 366                 }
 367
 368                 if (!found) {
 369                         MSG("Session name %s not found", session_name);
 370                         ret = CMD_ERROR;
 371                         goto free_sessions;
 372                 }
 373
 374                 session_live_mode = sessions[i].live_timer_interval;
 375
 376                 DBG("Session live mode set to %d", session_live_mode);
 377
 378                 if (sessions[i].enabled && !session_live_mode) {
 379                         WARN("Session %s is running. Please stop it before reading it.",
 380                                         session_name);
 381                         ret = CMD_ERROR;
 382                         goto free_sessions;
 383                 }
 384
 385                 /* If the timer interval is set we are in live mode. */
 386                 if (session_live_mode) {
 387                         trace_path = build_live_path(session_name);
 388                         if (!trace_path) {
 389                                 ret = CMD_ERROR;
 390                                 goto free_sessions;
 391                         }
 392                         free_trace_path = true;
 393                 } else {
 394                         /* Get file system session path. */
 395                         trace_path = sessions[i].path;
 396                 }
 397         } else {
 398                 trace_path = opt_trace_path;
 399         }
 400
 401         MSG("Trace directory: %s\n", trace_path);
 402
 403         ret = spawn_viewer(trace_path);
 404         if (ret < 0) {
 405                 /* Don't set ret so lttng can interpret the sessiond error. */
 406                 goto free_sessions;
 407         }
 408
 409 free_sessions:
 410         if (session_live_mode && free_trace_path) {
 411                 free(trace_path);
 412         }
 413         free(sessions);
 414 free_error:
 415         if (opt_session_name == NULL) {
 416                 free(session_name);
 417         }
 418 error:
 419         return ret;
 420 }
 421
 422 /*
 423  * The 'view <options>' first level command
 424  */
 425 int cmd_view(int argc, const char **argv)
 426 {
 427         int opt, ret = CMD_SUCCESS;
 428         static poptContext pc;
 429         const char *leftover = NULL;
 430
 431         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 432         poptReadDefaultConfig(pc, 0);
 433
 434         if (lttng_opt_mi) {
 435                 WARN("mi does not apply to view command");
 436         }
 437
 438         while ((opt = poptGetNextOpt(pc)) != -1) {
 439                 switch (opt) {
 440                 case OPT_HELP:
 441                         SHOW_HELP();
 442                         goto end;
 443                 case OPT_LIST_OPTIONS:
 444                         list_cmd_options(stdout, long_options);
 445                         goto end;
 446                 default:
 447                         ret = CMD_UNDEFINED;
 448                         goto end;
 449                 }
 450         }
 451
 452         opt_session_name = (char*) poptGetArg(pc);
 453
 454         leftover = poptGetArg(pc);
 455         if (leftover) {
 456                 ERR("Unknown argument: %s", leftover);
 457                 ret = CMD_ERROR;
 458                 goto end;
 459         }
 460
 461         ret = view_trace();
 462
 463 end:
 464         poptFreeContext(pc);
 465         return ret;
 466 }