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