src/bin/lttng/commands/view.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <dgoulet@efficios.com>
   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, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <popt.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26
  27 #include "../command.h"
  28
  29 static char *opt_session_name;
  30 static char *opt_viewer;
  31 static char *opt_trace_path;
  32 static const char *babeltrace_bin = CONFIG_BABELTRACE_BIN;
  33 static const char *babeltrace2_bin = CONFIG_BABELTRACE2_BIN;
  34
  35 #ifdef LTTNG_EMBED_HELP
  36 static const char help_msg[] =
  37 #include <lttng-view.1.h>
  38 ;
  39 #endif
  40
  41 enum {
  42         OPT_HELP = 1,
  43         OPT_LIST_OPTIONS,
  44 };
  45
  46 static struct poptOption long_options[] = {
  47         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  48         {"help",        'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  49         {"list-options", 0,  POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  50         {"viewer",      'e', POPT_ARG_STRING, &opt_viewer, 0, 0, 0},
  51         {"trace-path",  't', POPT_ARG_STRING, &opt_trace_path, 0, 0, 0},
  52         {0, 0, 0, 0, 0, 0, 0}
  53 };
  54
  55 /*
  56  * This is needed for each viewer since we are using execvp().
  57  */
  58 static const char *babeltrace_opts[] = { "babeltrace" };
  59 static const char *babeltrace2_opts[] = { "babeltrace2" };
  60
  61 /*
  62  * Type is also use as the index in the viewers array. So please, make sure
  63  * your enum value is in the right order in the array below.
  64  */
  65 enum viewer_type {
  66         VIEWER_BABELTRACE    = 0,
  67         VIEWER_BABELTRACE2   = 1,
  68         VIEWER_USER_DEFINED  = 2,
  69 };
  70
  71 /*
  72  * NOTE: "lttv" is a shell command and it's not working for exec() family
  73  * functions so we might think of removing this wrapper or using bash.
  74  */
  75 static const struct viewers {
  76         const char *exec_name;
  77         enum viewer_type type;
  78 } viewers[] = {
  79         { "babeltrace", VIEWER_BABELTRACE },
  80         { "babeltrace2", VIEWER_BABELTRACE2 },
  81         { NULL, VIEWER_USER_DEFINED },
  82 };
  83
  84 /* Is the session we are trying to view is in live mode. */
  85 static int session_live_mode;
  86
  87 static const struct viewers *parse_options(void)
  88 {
  89         if (opt_viewer == NULL) {
  90                 /* Default is babeltrace */
  91                 return &(viewers[VIEWER_BABELTRACE2]);
  92         }
  93
  94         /*
  95          * This means that if -e, --viewers is used, we just override everything
  96          * with it. For supported viewers like lttv, we could simply detect if "-t"
  97          * is passed and if not, add the trace directory to it.
  98          */
  99         return &(viewers[VIEWER_USER_DEFINED]);
 100 }
 101
 102 /*
 103  * Alloc an array of string pointer from a simple string having all options
 104  * seperated by spaces. Also adds the trace path to the arguments.
 105  *
 106  * The returning pointer is ready to be passed to execvp().
 107  */
 108 static char **alloc_argv_from_user_opts(char *opts, const char *trace_path)
 109 {
 110         int i = 0, ignore_space = 0;
 111         unsigned int num_opts = 1;
 112         char **argv, *token = opts;
 113
 114         /* Count number of arguments. */
 115         do {
 116                 if (*token == ' ') {
 117                         /* Use to ignore consecutive spaces */
 118                         if (!ignore_space) {
 119                                 num_opts++;
 120                         }
 121                         ignore_space = 1;
 122                 } else {
 123                         ignore_space = 0;
 124                 }
 125                 token++;
 126         } while (*token != '\0');
 127
 128         /* Add two here for the NULL terminating element and trace path */
 129         argv = zmalloc(sizeof(char *) * (num_opts + 2));
 130         if (argv == NULL) {
 131                 goto error;
 132         }
 133
 134         token = strtok(opts, " ");
 135         while (token != NULL) {
 136                 argv[i] = strdup(token);
 137                 if (argv[i] == NULL) {
 138                         goto error;
 139                 }
 140                 token = strtok(NULL, " ");
 141                 i++;
 142         }
 143
 144         argv[num_opts] = (char *) trace_path;
 145         argv[num_opts + 1] = NULL;
 146
 147         return argv;
 148
 149 error:
 150         if (argv) {
 151                 for (i = 0; i < num_opts + 2; i++) {
 152                         free(argv[i]);
 153                 }
 154                 free(argv);
 155         }
 156
 157         return NULL;
 158 }
 159
 160 /*
 161  * Alloc an array of string pointer from an array of strings. It also adds
 162  * the trace path to the argv.
 163  *
 164  * The returning pointer is ready to be passed to execvp().
 165  */
 166 static char **alloc_argv_from_local_opts(const char **opts, size_t opts_len,
 167                 const char *trace_path)
 168 {
 169         char **argv;
 170         size_t size, mem_len;
 171
 172         /* Add one for the NULL terminating element. */
 173         mem_len = opts_len + 1;
 174         if (session_live_mode) {
 175                 /* Add 3 option for the live mode being "-i lttng-live URL". */
 176                 mem_len += 3;
 177         } else {
 178                 /* Add option for the trace path. */
 179                 mem_len += 1;
 180         }
 181
 182         size = sizeof(char *) * mem_len;
 183
 184         /* Add two here for the trace_path and the NULL terminating element. */
 185         argv = zmalloc(size);
 186         if (argv == NULL) {
 187                 goto error;
 188         }
 189
 190         memcpy(argv, opts, sizeof(char *) * opts_len);
 191
 192         if (session_live_mode) {
 193                 argv[opts_len] = "-i";
 194                 argv[opts_len + 1] = "lttng-live";
 195                 argv[opts_len + 2] = (char *) trace_path;
 196                 argv[opts_len + 3] = NULL;
 197         } else {
 198                 argv[opts_len] = (char *) trace_path;
 199                 argv[opts_len + 1] = NULL;
 200         }
 201
 202 error:
 203         return argv;
 204 }
 205
 206 /*
 207  * Spawn viewer with the trace directory path.
 208  */
 209 static int spawn_viewer(const char *trace_path)
 210 {
 211         int ret = 0;
 212         struct stat status;
 213         const char *viewer_bin = NULL;
 214         const struct viewers *viewer;
 215         char **argv = NULL;
 216
 217         /* Check for --viewer options */
 218         viewer = parse_options();
 219         if (viewer == NULL) {
 220                 ret = CMD_ERROR;
 221                 goto error;
 222         }
 223
 224 retry_viewer:
 225         switch (viewer->type) {
 226         case VIEWER_BABELTRACE2:
 227                 if (stat(babeltrace2_bin, &status) == 0) {
 228                         viewer_bin = babeltrace2_bin;
 229                 } else {
 230                         viewer_bin = viewer->exec_name;
 231                 }
 232                 argv = alloc_argv_from_local_opts(babeltrace2_opts,
 233                                 ARRAY_SIZE(babeltrace2_opts), trace_path);
 234                 break;
 235         case VIEWER_BABELTRACE:
 236                 if (stat(babeltrace_bin, &status) == 0) {
 237                         viewer_bin = babeltrace_bin;
 238                 } else {
 239                         viewer_bin = viewer->exec_name;
 240                 }
 241                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 242                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 243                 break;
 244         case VIEWER_USER_DEFINED:
 245                 argv = alloc_argv_from_user_opts(opt_viewer, trace_path);
 246                 if (argv) {
 247                         viewer_bin = argv[0];
 248                 }
 249                 break;
 250         default:
 251                 viewer_bin = viewers[VIEWER_BABELTRACE].exec_name;
 252                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 253                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 254                 break;
 255         }
 256
 257         if (argv == NULL || !viewer_bin) {
 258                 ret = CMD_FATAL;
 259                 goto error;
 260         }
 261
 262         DBG("Using %s viewer", viewer_bin);
 263
 264         ret = execvp(viewer_bin, argv);
 265         if (ret) {
 266                 if (errno == ENOENT && viewer->exec_name) {
 267                         if (viewer->type == VIEWER_BABELTRACE2) {
 268                                 /* Fallback to legacy babeltrace. */
 269                                 DBG("babeltrace2 not installed on the system, falling back to babeltrace 1.x");
 270                                 viewer = &viewers[VIEWER_BABELTRACE];
 271                                 free(argv);
 272                                 argv = NULL;
 273                                 goto retry_viewer;
 274                         } else {
 275                                 ERR("Viewer \"%s\" not found on the system",
 276                                                 viewer_bin);
 277                         }
 278                 } else {
 279                         PERROR("Failed to launch \"%s\" viewer", viewer_bin);
 280                 }
 281                 ret = CMD_FATAL;
 282                 goto error;
 283         }
 284
 285 error:
 286         free(argv);
 287         return ret;
 288 }
 289
 290 /*
 291  * Build the live path we need for the lttng live view.
 292  */
 293 static char *build_live_path(char *session_name)
 294 {
 295         int ret;
 296         char *path = NULL;
 297         char hostname[HOST_NAME_MAX];
 298
 299         ret = gethostname(hostname, sizeof(hostname));
 300         if (ret < 0) {
 301                 PERROR("gethostname");
 302                 goto error;
 303         }
 304
 305         ret = asprintf(&path, "net://localhost/host/%s/%s", hostname,
 306                         session_name);
 307         if (ret < 0) {
 308                 PERROR("asprintf live path");
 309                 goto error;
 310         }
 311
 312 error:
 313         return path;
 314 }
 315
 316 /*
 317  * Exec viewer if found and use session name path.
 318  */
 319 static int view_trace(void)
 320 {
 321         int ret;
 322         char *session_name, *trace_path = NULL;
 323         struct lttng_session *sessions = NULL;
 324         bool free_trace_path = false;
 325
 326         /*
 327          * Safety net. If lttng is suid at some point for *any* useless reasons,
 328          * this prevent any bad execution of binaries.
 329          */
 330         if (getuid() != 0) {
 331                 if (getuid() != geteuid()) {
 332                         ERR("UID does not match effective UID.");
 333                         ret = CMD_ERROR;
 334                         goto error;
 335                 } else if (getgid() != getegid()) {
 336                         ERR("GID does not match effective GID.");
 337                         ret = CMD_ERROR;
 338                         goto error;
 339                 }
 340         }
 341
 342         /* User define trace path override the session name */
 343         if (opt_trace_path) {
 344                 session_name = NULL;
 345         } else if(opt_session_name == NULL) {
 346                 session_name = get_session_name();
 347                 if (session_name == NULL) {
 348                         ret = CMD_ERROR;
 349                         goto error;
 350                 }
 351         } else {
 352                 session_name = opt_session_name;
 353         }
 354
 355         DBG("Viewing trace for session %s", session_name);
 356
 357         if (session_name) {
 358                 int i, count, found = 0;
 359
 360                 /* Getting all sessions */
 361                 count = lttng_list_sessions(&sessions);
 362                 if (count < 0) {
 363                         ERR("Unable to list sessions. Session name %s not found.",
 364                                         session_name);
 365                         MSG("Is there a session daemon running?");
 366                         ret = CMD_ERROR;
 367                         goto free_error;
 368                 }
 369
 370                 /* Find our session listed by the session daemon */
 371                 for (i = 0; i < count; i++) {
 372                         if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 373                                 found = 1;
 374                                 break;
 375                         }
 376                 }
 377
 378                 if (!found) {
 379                         MSG("Session name %s not found", session_name);
 380                         ret = CMD_ERROR;
 381                         goto free_sessions;
 382                 }
 383
 384                 session_live_mode = sessions[i].live_timer_interval;
 385
 386                 DBG("Session live mode set to %d", session_live_mode);
 387
 388                 if (sessions[i].enabled && !session_live_mode) {
 389                         WARN("Session %s is running. Please stop it before reading it.",
 390                                         session_name);
 391                         ret = CMD_ERROR;
 392                         goto free_sessions;
 393                 }
 394
 395                 /* If the timer interval is set we are in live mode. */
 396                 if (session_live_mode) {
 397                         trace_path = build_live_path(session_name);
 398                         if (!trace_path) {
 399                                 ret = CMD_ERROR;
 400                                 goto free_sessions;
 401                         }
 402                         free_trace_path = true;
 403                 } else {
 404                         /* Get file system session path. */
 405                         trace_path = sessions[i].path;
 406                 }
 407         } else {
 408                 trace_path = opt_trace_path;
 409         }
 410
 411         MSG("Trace directory: %s\n", trace_path);
 412
 413         ret = spawn_viewer(trace_path);
 414         if (ret < 0) {
 415                 /* Don't set ret so lttng can interpret the sessiond error. */
 416                 goto free_sessions;
 417         }
 418
 419 free_sessions:
 420         if (session_live_mode && free_trace_path) {
 421                 free(trace_path);
 422         }
 423         free(sessions);
 424 free_error:
 425         if (opt_session_name == NULL) {
 426                 free(session_name);
 427         }
 428 error:
 429         return ret;
 430 }
 431
 432 /*
 433  * The 'view <options>' first level command
 434  */
 435 int cmd_view(int argc, const char **argv)
 436 {
 437         int opt, ret = CMD_SUCCESS;
 438         static poptContext pc;
 439         const char *leftover = NULL;
 440
 441         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 442         poptReadDefaultConfig(pc, 0);
 443
 444         if (lttng_opt_mi) {
 445                 WARN("mi does not apply to view command");
 446         }
 447
 448         while ((opt = poptGetNextOpt(pc)) != -1) {
 449                 switch (opt) {
 450                 case OPT_HELP:
 451                         SHOW_HELP();
 452                         goto end;
 453                 case OPT_LIST_OPTIONS:
 454                         list_cmd_options(stdout, long_options);
 455                         goto end;
 456                 default:
 457                         ret = CMD_UNDEFINED;
 458                         goto end;
 459                 }
 460         }
 461
 462         opt_session_name = (char*) poptGetArg(pc);
 463
 464         leftover = poptGetArg(pc);
 465         if (leftover) {
 466                 ERR("Unknown argument: %s", leftover);
 467                 ret = CMD_ERROR;
 468                 goto end;
 469         }
 470
 471         ret = view_trace();
 472
 473 end:
 474         poptFreeContext(pc);
 475         return ret;
 476 }