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 _GNU_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 #include <config.h>
  29
  30 static char *opt_session_name;
  31 static char *opt_viewer;
  32 static char *opt_trace_path;
  33 static const char *babeltrace_bin = CONFIG_BABELTRACE_BIN;
  34 //static const char *lttv_gui_bin = CONFIG_LTTV_GUI_BIN;
  35
  36 enum {
  37         OPT_HELP = 1,
  38         OPT_LIST_OPTIONS,
  39 };
  40
  41 static struct poptOption long_options[] = {
  42         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  43         {"help",        'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  44         {"list-options", 0,  POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  45         {"viewer",      'e', POPT_ARG_STRING, &opt_viewer, 0, 0, 0},
  46         {"trace-path",  't', POPT_ARG_STRING, &opt_trace_path, 0, 0, 0},
  47         {0, 0, 0, 0, 0, 0, 0}
  48 };
  49
  50 /*
  51  * This is needed for each viewer since we are using execvp().
  52  */
  53 static const char *babeltrace_opts[] = { "babeltrace" };
  54 //static const char *lttv_gui_opts[] = { "lttv-gui", "-t", };
  55
  56 /*
  57  * Type is also use as the index in the viewers array. So please, make sure
  58  * your enum value is in the right order in the array below.
  59  */
  60 enum viewer_type {
  61         VIEWER_BABELTRACE    = 0,
  62         VIEWER_LTTV_GUI      = 1,
  63         VIEWER_USER_DEFINED  = 2,
  64 };
  65
  66 /*
  67  * NOTE: "lttv" is a shell command and it's not working for exec() family
  68  * functions so we might think of removing this wrapper or using bash.
  69  */
  70 static struct viewers {
  71         const char *exec_name;
  72         enum viewer_type type;
  73 } viewers[] = {
  74         { "babeltrace", VIEWER_BABELTRACE },
  75         { "lttv-gui", VIEWER_LTTV_GUI },
  76         { NULL, VIEWER_USER_DEFINED },
  77 };
  78
  79 /*
  80  * usage
  81  */
  82 static void usage(FILE *ofp)
  83 {
  84         fprintf(ofp, "usage: lttng view [SESSION_NAME] [OPTIONS]\n");
  85         fprintf(ofp, "\n");
  86         fprintf(ofp, "By default, the babeltrace viewer will be used for text viewing\n");
  87         fprintf(ofp, "\n");
  88         fprintf(ofp, "Where SESSION_NAME is an optional session name. If not specified, lttng will\n");
  89         fprintf(ofp, "get it from the configuration file (.lttngrc).\n");
  90         fprintf(ofp, "\n");
  91         fprintf(ofp, "  -h, --help               Show this help\n");
  92         fprintf(ofp, "      --list-options       Simple listing of options\n");
  93         fprintf(ofp, "  -t, --trace-path PATH    Trace directory path for the viewer\n");
  94         fprintf(ofp, "  -e, --viewer CMD         Specify viewer and/or options to use\n");
  95         fprintf(ofp, "                           This will completely override the default viewers so\n");
  96         fprintf(ofp, "                           please make sure to specify the full command. The trace\n");
  97         fprintf(ofp, "                           directory path of the session will be appended at the end\n");
  98         fprintf(ofp, "                           to the arguments\n");
  99         fprintf(ofp, "\n");
 100 }
 101
 102 static struct viewers *parse_options(void)
 103 {
 104         if (opt_viewer == NULL) {
 105                 /* Default is babeltrace */
 106                 return &(viewers[VIEWER_BABELTRACE]);
 107         }
 108
 109 #if 0
 110         if (strstr(opt_viewer, viewers[VIEWER_LTTV_GUI].exec_name) == 0) {
 111                 return &(viewers[VIEWER_LTTV_GUI]);
 112         }
 113 #endif
 114
 115         /*
 116          * This means that if -e, --viewers is used, we just override everything
 117          * with it. For supported viewers like lttv, we could simply detect if "-t"
 118          * is passed and if not, add the trace directory to it.
 119          */
 120         return &(viewers[VIEWER_USER_DEFINED]);
 121 }
 122
 123 /*
 124  * Alloc an array of string pointer from a simple string having all options
 125  * seperated by spaces. Also adds the trace path to the arguments.
 126  *
 127  * The returning pointer is ready to be passed to execvp().
 128  */
 129 static char **alloc_argv_from_user_opts(char *opts, const char *trace_path)
 130 {
 131         int i = 0, ignore_space = 0;
 132         unsigned int num_opts = 1;
 133         char **argv, *token = opts;
 134
 135         /* Count number of arguments. */
 136         do {
 137                 if (*token == ' ') {
 138                         /* Use to ignore consecutive spaces */
 139                         if (!ignore_space) {
 140                                 num_opts++;
 141                         }
 142                         ignore_space = 1;
 143                 } else {
 144                         ignore_space = 0;
 145                 }
 146                 token++;
 147         } while (*token != '\0');
 148
 149         /* Add two here for the NULL terminating element and trace path */
 150         argv = malloc(sizeof(char *) * (num_opts + 2));
 151         if (argv == NULL) {
 152                 goto error;
 153         }
 154
 155         token = strtok(opts, " ");
 156         while (token != NULL) {
 157                 argv[i] = strdup(token);
 158                 token = strtok(NULL, " ");
 159                 i++;
 160         }
 161
 162         argv[num_opts] = (char *) trace_path;
 163         argv[num_opts + 1] = NULL;
 164
 165         return argv;
 166
 167 error:
 168         return NULL;
 169 }
 170
 171 /*
 172  * Alloc an array of string pointer from an array of strings. It also adds
 173  * the trace path to the argv.
 174  *
 175  * The returning pointer is ready to be passed to execvp().
 176  */
 177 static char **alloc_argv_from_local_opts(const char **opts, size_t opts_len,
 178                 const char *trace_path)
 179 {
 180         char **argv;
 181         size_t size;
 182
 183         size = sizeof(char *) * opts_len;
 184
 185         /* Add two here for the trace_path and the NULL terminating element. */
 186         argv = malloc(size + 2);
 187         if (argv == NULL) {
 188                 goto error;
 189         }
 190
 191         memcpy(argv, opts, size);
 192
 193         argv[opts_len] = (char *)trace_path;
 194         argv[opts_len + 1] = NULL;
 195
 196 error:
 197         return argv;
 198 }
 199
 200 /*
 201  * Spawn viewer with the trace directory path.
 202  */
 203 static int spawn_viewer(const char *trace_path)
 204 {
 205         int ret = 0;
 206         struct stat status;
 207         const char *viewer_bin = NULL;
 208         struct viewers *viewer;
 209         char **argv = NULL;
 210
 211         /* Check for --viewer options */
 212         viewer = parse_options();
 213         if (viewer == NULL) {
 214                 ret = CMD_ERROR;
 215                 goto error;
 216         }
 217
 218         switch (viewer->type) {
 219         case VIEWER_BABELTRACE:
 220                 if (stat(babeltrace_bin, &status) == 0) {
 221                         viewer_bin = babeltrace_bin;
 222                 } else {
 223                         viewer_bin = viewer->exec_name;
 224                 }
 225                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 226                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 227                 break;
 228 #if 0
 229         case VIEWER_LTTV_GUI:
 230                 if (stat(lttv_gui_bin, &status) == 0) {
 231                         viewer_bin = lttv_gui_bin;
 232                 } else {
 233                         viewer_bin = viewer->exec_name;
 234                 }
 235                 argv = alloc_argv_from_local_opts(lttv_gui_opts,
 236                                 ARRAY_SIZE(lttv_gui_opts), trace_path);
 237                 break;
 238 #endif
 239         case VIEWER_USER_DEFINED:
 240                 argv = alloc_argv_from_user_opts(opt_viewer, trace_path);
 241                 if (argv) {
 242                         viewer_bin = argv[0];
 243                 }
 244                 break;
 245         default:
 246                 viewer_bin = viewers[VIEWER_BABELTRACE].exec_name;
 247                 argv = alloc_argv_from_local_opts(babeltrace_opts,
 248                                 ARRAY_SIZE(babeltrace_opts), trace_path);
 249                 break;
 250         }
 251
 252         if (argv == NULL) {
 253                 ret = CMD_FATAL;
 254                 goto error;
 255         }
 256
 257         DBG("Using %s viewer", viewer_bin);
 258
 259         ret = execvp(viewer_bin, argv);
 260         if (ret) {
 261                 if (errno == ENOENT) {
 262                         ERR("%s not found on the system", viewer_bin);
 263                 } else {
 264                         PERROR("exec: %s", viewer_bin);
 265                 }
 266                 free(argv);
 267                 ret = CMD_FATAL;
 268                 goto error;
 269         }
 270
 271 error:
 272         return ret;
 273 }
 274
 275 /*
 276  * Exec viewer if found and use session name path.
 277  */
 278 static int view_trace(void)
 279 {
 280         int ret, count, i, found = 0;
 281         char *session_name, *trace_path;
 282         struct lttng_session *sessions = NULL;
 283
 284         /*
 285          * Safety net. If lttng is suid at some point for *any* useless reasons,
 286          * this prevent any bad execution of binaries.
 287          */
 288         if (getuid() != 0) {
 289                 if (getuid() != geteuid()) {
 290                         ERR("UID does not match effective UID.");
 291                         ret = CMD_ERROR;
 292                         goto error;
 293                 } else if (getgid() != getegid()) {
 294                         ERR("GID does not match effective GID.");
 295                         ret = CMD_ERROR;
 296                         goto error;
 297                 }
 298         }
 299
 300         /* User define trace path override the session name */
 301         if (opt_trace_path) {
 302                 session_name = NULL;
 303         } else if(opt_session_name == NULL) {
 304                 session_name = get_session_name();
 305                 if (session_name == NULL) {
 306                         ret = CMD_ERROR;
 307                         goto error;
 308                 }
 309         } else {
 310                 session_name = opt_session_name;
 311         }
 312
 313         DBG("Viewing trace for session %s", session_name);
 314
 315         if (session_name) {
 316                 /* Getting all sessions */
 317                 count = lttng_list_sessions(&sessions);
 318                 if (count < 0) {
 319                         ERR("Unable to list sessions. Session name %s not found.",
 320                                         session_name);
 321                         MSG("Is there a session daemon running?");
 322                         ret = CMD_ERROR;
 323                         goto free_error;
 324                 }
 325
 326                 /* Find our session listed by the session daemon */
 327                 for (i = 0; i < count; i++) {
 328                         if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 329                                 found = 1;
 330                                 break;
 331                         }
 332                 }
 333
 334                 if (!found) {
 335                         MSG("Session name %s not found", session_name);
 336                         ret = CMD_ERROR;
 337                         goto free_sessions;
 338                 }
 339
 340                 trace_path = sessions[i].path;
 341         } else {
 342                 trace_path = opt_trace_path;
 343         }
 344
 345         MSG("Trace directory: %s\n", trace_path);
 346
 347         ret = spawn_viewer(trace_path);
 348         if (ret < 0) {
 349                 /* Don't set ret so lttng can interpret the sessiond error. */
 350                 goto free_sessions;
 351         }
 352
 353 free_sessions:
 354         if (sessions) {
 355                 free(sessions);
 356         }
 357 free_error:
 358         if (opt_session_name == NULL) {
 359                 free(session_name);
 360         }
 361 error:
 362         return ret;
 363 }
 364
 365 /*
 366  * The 'view <options>' first level command
 367  */
 368 int cmd_view(int argc, const char **argv)
 369 {
 370         int opt, ret = CMD_SUCCESS;
 371         static poptContext pc;
 372
 373         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 374         poptReadDefaultConfig(pc, 0);
 375
 376         while ((opt = poptGetNextOpt(pc)) != -1) {
 377                 switch (opt) {
 378                 case OPT_HELP:
 379                         usage(stdout);
 380                         goto end;
 381                 case OPT_LIST_OPTIONS:
 382                         list_cmd_options(stdout, long_options);
 383                         goto end;
 384                 default:
 385                         usage(stderr);
 386                         ret = CMD_UNDEFINED;
 387                         goto end;
 388                 }
 389         }
 390
 391         opt_session_name = (char*) poptGetArg(pc);
 392
 393         ret = view_trace();
 394
 395 end:
 396         poptFreeContext(pc);
 397         return ret;
 398 }