src/bin/lttng/commands/enable_events.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <popt.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/stat.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27 #include <inttypes.h>
  28 #include <ctype.h>
  29
  30 #include "../command.h"
  31
  32 static char *opt_event_list;
  33 static int opt_event_type;
  34 static const char *opt_loglevel;
  35 static int opt_loglevel_type;
  36 static int opt_kernel;
  37 static char *opt_session_name;
  38 static int opt_userspace;
  39 static int opt_enable_all;
  40 static char *opt_probe;
  41 static char *opt_function;
  42 static char *opt_function_entry_symbol;
  43 static char *opt_channel_name;
  44 #if 0
  45 /* Not implemented yet */
  46 static char *opt_cmd_name;
  47 static pid_t opt_pid;
  48 #endif
  49
  50 enum {
  51         OPT_HELP = 1,
  52         OPT_TRACEPOINT,
  53         OPT_PROBE,
  54         OPT_FUNCTION,
  55         OPT_FUNCTION_ENTRY,
  56         OPT_SYSCALL,
  57         OPT_USERSPACE,
  58         OPT_LOGLEVEL,
  59         OPT_LOGLEVEL_ONLY,
  60         OPT_LIST_OPTIONS,
  61 };
  62
  63 static struct lttng_handle *handle;
  64
  65 static struct poptOption long_options[] = {
  66         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  67         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  68         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  69         {"all",            'a', POPT_ARG_VAL, &opt_enable_all, 1, 0, 0},
  70         {"channel",        'c', POPT_ARG_STRING, &opt_channel_name, 0, 0, 0},
  71         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  72 #if 0
  73         /* Not implemented yet */
  74         {"userspace",      'u', POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_cmd_name, OPT_USERSPACE, 0, 0},
  75         {"pid",            'p', POPT_ARG_INT, &opt_pid, 0, 0, 0},
  76 #else
  77         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  78 #endif
  79         {"tracepoint",     0,   POPT_ARG_NONE, 0, OPT_TRACEPOINT, 0, 0},
  80         {"probe",          0,   POPT_ARG_STRING, &opt_probe, OPT_PROBE, 0, 0},
  81         {"function",       0,   POPT_ARG_STRING, &opt_function, OPT_FUNCTION, 0, 0},
  82 #if 0
  83         /*
  84          * Currently removed from lttng kernel tracer. Removed from
  85          * lttng UI to discourage its use.
  86          */
  87         {"function:entry", 0,   POPT_ARG_STRING, &opt_function_entry_symbol, OPT_FUNCTION_ENTRY, 0, 0},
  88 #endif
  89         {"syscall",        0,   POPT_ARG_NONE, 0, OPT_SYSCALL, 0, 0},
  90         {"loglevel",       0,     POPT_ARG_STRING, 0, OPT_LOGLEVEL, 0, 0},
  91         {"loglevel-only",  0,     POPT_ARG_STRING, 0, OPT_LOGLEVEL_ONLY, 0, 0},
  92         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  93         {0, 0, 0, 0, 0, 0, 0}
  94 };
  95
  96 /*
  97  * usage
  98  */
  99 static void usage(FILE *ofp)
 100 {
 101         fprintf(ofp, "usage: lttng enable-event NAME[,NAME2,...] [options] [event_options]\n");
 102         fprintf(ofp, "\n");
 103         fprintf(ofp, "  -h, --help               Show this help\n");
 104         fprintf(ofp, "      --list-options       Simple listing of options\n");
 105         fprintf(ofp, "  -s, --session            Apply to session name\n");
 106         fprintf(ofp, "  -c, --channel            Apply to this channel\n");
 107         fprintf(ofp, "  -a, --all                Enable all tracepoints\n");
 108         fprintf(ofp, "  -k, --kernel             Apply for the kernel tracer\n");
 109 #if 0
 110         fprintf(ofp, "  -u, --userspace [CMD]    Apply to the user-space tracer\n");
 111         fprintf(ofp, "                           If no CMD, the domain used is UST global\n");
 112         fprintf(ofp, "                           or else the domain is UST EXEC_NAME\n");
 113         fprintf(ofp, "  -p, --pid PID            If -u, apply to specific PID (domain: UST PID)\n");
 114 #else
 115         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
 116 #endif
 117         fprintf(ofp, "\n");
 118         fprintf(ofp, "Event options:\n");
 119         fprintf(ofp, "    --tracepoint           Tracepoint event (default)\n");
 120         fprintf(ofp, "                           - userspace tracer supports wildcards at end of string.\n");
 121         fprintf(ofp, "                             Don't forget to quote to deal with bash expansion.\n");
 122         fprintf(ofp, "                             e.g.:\n");
 123         fprintf(ofp, "                               \"*\"\n");
 124         fprintf(ofp, "                               \"app_component:na*\"\n");
 125         fprintf(ofp, "    --probe [addr | symbol | symbol+offset]\n");
 126         fprintf(ofp, "                           Dynamic probe.\n");
 127         fprintf(ofp, "                           Addr and offset can be octal (0NNN...),\n");
 128         fprintf(ofp, "                           decimal (NNN...) or hexadecimal (0xNNN...)\n");
 129         fprintf(ofp, "    --function [addr | symbol | symbol+offset]\n");
 130         fprintf(ofp, "                           Dynamic function entry/return probe.\n");
 131         fprintf(ofp, "                           Addr and offset can be octal (0NNN...),\n");
 132         fprintf(ofp, "                           decimal (NNN...) or hexadecimal (0xNNN...)\n");
 133 #if 0
 134         fprintf(ofp, "    --function:entry symbol\n");
 135         fprintf(ofp, "                           Function tracer event\n");
 136 #endif
 137         fprintf(ofp, "    --syscall              System call event\n");
 138         fprintf(ofp, "\n");
 139         fprintf(ofp, "    --loglevel name\n");
 140         fprintf(ofp, "                           Tracepoint loglevel range from 0 to loglevel\n");
 141         fprintf(ofp, "    --loglevel-only name\n");
 142         fprintf(ofp, "                           Tracepoint loglevel (only this loglevel)\n");
 143         fprintf(ofp, "\n");
 144         fprintf(ofp, "                           The loglevel or loglevel-only options should be\n");
 145         fprintf(ofp, "                           combined with a tracepoint name or tracepoint\n");
 146         fprintf(ofp, "                           wildcard.\n");
 147         fprintf(ofp, "                           Available loglevels:\n");
 148         fprintf(ofp, "                                              (higher value is more verbose)\n");
 149         fprintf(ofp, "                               TRACE_EMERG    = 0\n");
 150         fprintf(ofp, "                               TRACE_ALERT    = 1\n");
 151         fprintf(ofp, "                               TRACE_CRIT     = 2\n");
 152         fprintf(ofp, "                               TRACE_ERR      = 3\n");
 153         fprintf(ofp, "                               TRACE_WARNING  = 4\n");
 154         fprintf(ofp, "                               TRACE_NOTICE   = 5\n");
 155         fprintf(ofp, "                               TRACE_INFO     = 6\n");
 156         fprintf(ofp, "                               TRACE_SYSTEM   = 7\n");
 157         fprintf(ofp, "                               TRACE_PROGRAM  = 8\n");
 158         fprintf(ofp, "                               TRACE_PROCESS  = 9\n");
 159         fprintf(ofp, "                               TRACE_MODULE   = 10\n");
 160         fprintf(ofp, "                               TRACE_UNIT     = 11\n");
 161         fprintf(ofp, "                               TRACE_FUNCTION = 12\n");
 162         fprintf(ofp, "                               TRACE_DEFAULT  = 13\n");
 163         fprintf(ofp, "                               TRACE_VERBOSE  = 14\n");
 164         fprintf(ofp, "                               TRACE_DEBUG    = 15\n");
 165         fprintf(ofp, "\n");
 166 }
 167
 168 /*
 169  * Parse probe options.
 170  */
 171 static int parse_probe_opts(struct lttng_event *ev, char *opt)
 172 {
 173         int ret;
 174         char s_hex[19];
 175         char name[LTTNG_SYMBOL_NAME_LEN];
 176
 177         if (opt == NULL) {
 178                 ret = -1;
 179                 goto end;
 180         }
 181
 182         /* Check for symbol+offset */
 183         ret = sscanf(opt, "%[^'+']+%s", name, s_hex);
 184         if (ret == 2) {
 185                 strncpy(ev->attr.probe.symbol_name, name, LTTNG_SYMBOL_NAME_LEN);
 186                 ev->attr.probe.symbol_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 187                 DBG("probe symbol %s", ev->attr.probe.symbol_name);
 188                 if (strlen(s_hex) == 0) {
 189                         ERR("Invalid probe offset %s", s_hex);
 190                         ret = -1;
 191                         goto end;
 192                 }
 193                 ev->attr.probe.offset = strtoul(s_hex, NULL, 0);
 194                 DBG("probe offset %" PRIu64, ev->attr.probe.offset);
 195                 ev->attr.probe.addr = 0;
 196                 goto end;
 197         }
 198
 199         /* Check for symbol */
 200         if (isalpha(name[0])) {
 201                 ret = sscanf(opt, "%s", name);
 202                 if (ret == 1) {
 203                         strncpy(ev->attr.probe.symbol_name, name, LTTNG_SYMBOL_NAME_LEN);
 204                         ev->attr.probe.symbol_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 205                         DBG("probe symbol %s", ev->attr.probe.symbol_name);
 206                         ev->attr.probe.offset = 0;
 207                         DBG("probe offset %" PRIu64, ev->attr.probe.offset);
 208                         ev->attr.probe.addr = 0;
 209                         goto end;
 210                 }
 211         }
 212
 213         /* Check for address */
 214         ret = sscanf(opt, "%s", s_hex);
 215         if (ret > 0) {
 216                 if (strlen(s_hex) == 0) {
 217                         ERR("Invalid probe address %s", s_hex);
 218                         ret = -1;
 219                         goto end;
 220                 }
 221                 ev->attr.probe.addr = strtoul(s_hex, NULL, 0);
 222                 DBG("probe addr %" PRIu64, ev->attr.probe.addr);
 223                 ev->attr.probe.offset = 0;
 224                 memset(ev->attr.probe.symbol_name, 0, LTTNG_SYMBOL_NAME_LEN);
 225                 goto end;
 226         }
 227
 228         /* No match */
 229         ret = -1;
 230
 231 end:
 232         return ret;
 233 }
 234
 235 /*
 236  * Maps loglevel from string to value
 237  */
 238 static
 239 int loglevel_str_to_value(const char *str)
 240 {
 241         if (!strcmp(str, "TRACE_EMERG")) {
 242                 return 0;
 243         } else if (!strcmp(str, "TRACE_ALERT")) {
 244                 return 1;
 245         } else if (!strcmp(str, "TRACE_CRIT")) {
 246                 return 2;
 247         } else if (!strcmp(str, "TRACE_ERR")) {
 248                 return 3;
 249         } else if (!strcmp(str, "TRACE_WARNING")) {
 250                 return 4;
 251         } else if (!strcmp(str, "TRACE_NOTICE")) {
 252                 return 5;
 253         } else if (!strcmp(str, "TRACE_INFO")) {
 254                 return 6;
 255         } else if (!strcmp(str, "TRACE_SYSTEM")) {
 256                 return 7;
 257         } else if (!strcmp(str, "TRACE_PROGRAM")) {
 258                 return 8;
 259         } else if (!strcmp(str, "TRACE_PROCESS")) {
 260                 return 9;
 261         } else if (!strcmp(str, "TRACE_MODULE")) {
 262                 return 10;
 263         } else if (!strcmp(str, "TRACE_UNIT")) {
 264                 return 11;
 265         } else if (!strcmp(str, "TRACE_FUNCTION")) {
 266                 return 12;
 267         } else if (!strcmp(str, "TRACE_DEFAULT")) {
 268                 return 13;
 269         } else if (!strcmp(str, "TRACE_VERBOSE")) {
 270                 return 14;
 271         } else if (!strcmp(str, "TRACE_DEBUG")) {
 272                 return 15;
 273         } else {
 274                 return -1;
 275         }
 276 }
 277
 278 /*
 279  * Enabling event using the lttng API.
 280  */
 281 static int enable_events(char *session_name)
 282 {
 283         int err, ret = CMD_SUCCESS, warn = 0;
 284         char *event_name, *channel_name = NULL;
 285         struct lttng_event ev;
 286         struct lttng_domain dom;
 287
 288         /* Create lttng domain */
 289         if (opt_kernel) {
 290                 dom.type = LTTNG_DOMAIN_KERNEL;
 291         } else if (opt_userspace) {
 292                 dom.type = LTTNG_DOMAIN_UST;
 293         } else {
 294                 ERR("Please specify a tracer (-k/--kernel or -u/--userspace)");
 295                 ret = CMD_ERROR;
 296                 goto error;
 297         }
 298
 299         if (opt_channel_name == NULL) {
 300                 err = asprintf(&channel_name, DEFAULT_CHANNEL_NAME);
 301                 if (err < 0) {
 302                         ret = CMD_FATAL;
 303                         goto error;
 304                 }
 305         } else {
 306                 channel_name = opt_channel_name;
 307         }
 308
 309         handle = lttng_create_handle(session_name, &dom);
 310         if (handle == NULL) {
 311                 ret = -1;
 312                 goto error;
 313         }
 314
 315         if (opt_enable_all) {
 316                 /* Default setup for enable all */
 317                 if (opt_kernel) {
 318                         ev.type = opt_event_type;
 319                         ev.name[0] = '\0';
 320                         /* kernel loglevels not implemented */
 321                         ev.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
 322                 } else {
 323                         ev.type = LTTNG_EVENT_TRACEPOINT;
 324                         strcpy(ev.name, "*");
 325                         ev.loglevel_type = opt_loglevel_type;
 326                         if (opt_loglevel) {
 327                                 ev.loglevel = loglevel_str_to_value(opt_loglevel);
 328                                 if (ev.loglevel == -1) {
 329                                         ERR("Unknown loglevel %s", opt_loglevel);
 330                                         ret = -1;
 331                                         goto error;
 332                                 }
 333                         }
 334                 }
 335
 336                 ret = lttng_enable_event(handle, &ev, channel_name);
 337                 if (ret < 0) {
 338                         goto error;
 339                 }
 340
 341                 switch (opt_event_type) {
 342                 case LTTNG_EVENT_TRACEPOINT:
 343                         MSG("All %s tracepoints are enabled in channel %s for loglevel %s",
 344                                 opt_kernel ? "kernel" : "UST", channel_name,
 345                                 opt_loglevel ? : "<all>");
 346                         break;
 347                 case LTTNG_EVENT_SYSCALL:
 348                         if (opt_kernel) {
 349                                 MSG("All kernel system calls are enabled in channel %s",
 350                                                 channel_name);
 351                         }
 352                         break;
 353                 case LTTNG_EVENT_ALL:
 354                         MSG("All %s events are enabled in channel %s for loglevel %s",
 355                                 opt_kernel ? "kernel" : "UST", channel_name,
 356                                 opt_loglevel ? : "<all>");
 357                         break;
 358                 default:
 359                         /*
 360                          * We should not be here since lttng_enable_event should have
 361                          * failed on the event type.
 362                          */
 363                         goto error;
 364                 }
 365                 goto end;
 366         }
 367
 368         /* Strip event list */
 369         event_name = strtok(opt_event_list, ",");
 370         while (event_name != NULL) {
 371                 /* Copy name and type of the event */
 372                 strncpy(ev.name, event_name, LTTNG_SYMBOL_NAME_LEN);
 373                 ev.name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 374                 ev.type = opt_event_type;
 375
 376                 /* Kernel tracer action */
 377                 if (opt_kernel) {
 378                         DBG("Enabling kernel event %s for channel %s",
 379                                         event_name, channel_name);
 380
 381                         switch (opt_event_type) {
 382                         case LTTNG_EVENT_ALL:   /* Default behavior is tracepoint */
 383                                 ev.type = LTTNG_EVENT_TRACEPOINT;
 384                                 /* Fall-through */
 385                         case LTTNG_EVENT_TRACEPOINT:
 386                                 break;
 387                         case LTTNG_EVENT_PROBE:
 388                                 ret = parse_probe_opts(&ev, opt_probe);
 389                                 if (ret < 0) {
 390                                         ERR("Unable to parse probe options");
 391                                         ret = 0;
 392                                         goto error;
 393                                 }
 394                                 break;
 395                         case LTTNG_EVENT_FUNCTION:
 396                                 ret = parse_probe_opts(&ev, opt_function);
 397                                 if (ret < 0) {
 398                                         ERR("Unable to parse function probe options");
 399                                         ret = 0;
 400                                         goto error;
 401                                 }
 402                                 break;
 403                         case LTTNG_EVENT_FUNCTION_ENTRY:
 404                                 strncpy(ev.attr.ftrace.symbol_name, opt_function_entry_symbol,
 405                                                 LTTNG_SYMBOL_NAME_LEN);
 406                                 ev.attr.ftrace.symbol_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 407                                 break;
 408                         case LTTNG_EVENT_SYSCALL:
 409                                 MSG("per-syscall selection not supported yet. Use \"-a\" "
 410                                                 "for all syscalls.");
 411                         default:
 412                                 ret = CMD_UNDEFINED;
 413                                 goto error;
 414                         }
 415
 416                         if (opt_loglevel) {
 417                                 MSG("Kernel loglevels are not supported.");
 418                                 ret = CMD_UNDEFINED;
 419                                 goto error;
 420                         }
 421
 422                         /* kernel loglevels not implemented */
 423                         ev.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
 424                 } else if (opt_userspace) {             /* User-space tracer action */
 425 #if 0
 426                         if (opt_cmd_name != NULL || opt_pid) {
 427                                 MSG("Only supporting tracing all UST processes (-u) for now.");
 428                                 ret = CMD_UNDEFINED;
 429                                 goto error;
 430                         }
 431 #endif
 432
 433                         DBG("Enabling UST event %s for channel %s, loglevel %s", event_name,
 434                                         channel_name, opt_loglevel ? : "<all>");
 435
 436                         switch (opt_event_type) {
 437                         case LTTNG_EVENT_ALL:   /* Default behavior is tracepoint */
 438                                 /* Fall-through */
 439                         case LTTNG_EVENT_TRACEPOINT:
 440                                 /* Copy name and type of the event */
 441                                 ev.type = LTTNG_EVENT_TRACEPOINT;
 442                                 strncpy(ev.name, event_name, LTTNG_SYMBOL_NAME_LEN);
 443                                 ev.name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 444                                 break;
 445                         case LTTNG_EVENT_PROBE:
 446                         case LTTNG_EVENT_FUNCTION:
 447                         case LTTNG_EVENT_FUNCTION_ENTRY:
 448                         case LTTNG_EVENT_SYSCALL:
 449                         default:
 450                                 ERR("Event type not available for user-space tracing");
 451                                 ret = CMD_UNDEFINED;
 452                                 goto error;
 453                         }
 454
 455                         ev.loglevel_type = opt_loglevel_type;
 456                         if (opt_loglevel) {
 457                                 ev.loglevel = loglevel_str_to_value(opt_loglevel);
 458                                 if (ev.loglevel == -1) {
 459                                         ERR("Unknown loglevel %s", opt_loglevel);
 460                                         ret = -1;
 461                                         goto error;
 462                                 }
 463                         }
 464                 } else {
 465                         ERR("Please specify a tracer (-k/--kernel or -u/--userspace)");
 466                         ret = CMD_ERROR;
 467                         goto error;
 468                 }
 469
 470                 ret = lttng_enable_event(handle, &ev, channel_name);
 471                 if (ret < 0) {
 472                         ERR("Event %s: %s (channel %s, session %s)", event_name,
 473                                         lttng_strerror(ret), channel_name, session_name);
 474                         warn = 1;
 475                 } else {
 476                         MSG("%s event %s created in channel %s",
 477                                         opt_kernel ? "kernel": "UST", event_name, channel_name);
 478                 }
 479
 480                 /* Next event */
 481                 event_name = strtok(NULL, ",");
 482         }
 483
 484 end:
 485 error:
 486         if (warn) {
 487                 ret = CMD_WARNING;
 488         }
 489         if (opt_channel_name == NULL) {
 490                 free(channel_name);
 491         }
 492         lttng_destroy_handle(handle);
 493
 494         return ret;
 495 }
 496
 497 /*
 498  * Add event to trace session
 499  */
 500 int cmd_enable_events(int argc, const char **argv)
 501 {
 502         int opt, ret = CMD_SUCCESS;
 503         static poptContext pc;
 504         char *session_name = NULL;
 505
 506         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 507         poptReadDefaultConfig(pc, 0);
 508
 509         /* Default event type */
 510         opt_event_type = LTTNG_EVENT_ALL;
 511
 512         while ((opt = poptGetNextOpt(pc)) != -1) {
 513                 switch (opt) {
 514                 case OPT_HELP:
 515                         usage(stdout);
 516                         goto end;
 517                 case OPT_TRACEPOINT:
 518                         opt_event_type = LTTNG_EVENT_TRACEPOINT;
 519                         break;
 520                 case OPT_PROBE:
 521                         opt_event_type = LTTNG_EVENT_PROBE;
 522                         break;
 523                 case OPT_FUNCTION:
 524                         opt_event_type = LTTNG_EVENT_FUNCTION;
 525                         break;
 526                 case OPT_FUNCTION_ENTRY:
 527                         opt_event_type = LTTNG_EVENT_FUNCTION_ENTRY;
 528                         break;
 529                 case OPT_SYSCALL:
 530                         opt_event_type = LTTNG_EVENT_SYSCALL;
 531                         break;
 532                 case OPT_USERSPACE:
 533                         opt_userspace = 1;
 534                         break;
 535                 case OPT_LOGLEVEL:
 536                         opt_loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
 537                         opt_loglevel = poptGetOptArg(pc);
 538                         break;
 539                 case OPT_LOGLEVEL_ONLY:
 540                         opt_loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
 541                         opt_loglevel = poptGetOptArg(pc);
 542                         break;
 543                 case OPT_LIST_OPTIONS:
 544                         list_cmd_options(stdout, long_options);
 545                         goto end;
 546                 default:
 547                         usage(stderr);
 548                         ret = CMD_UNDEFINED;
 549                         goto end;
 550                 }
 551         }
 552
 553         opt_event_list = (char*) poptGetArg(pc);
 554         if (opt_event_list == NULL && opt_enable_all == 0) {
 555                 ERR("Missing event name(s).\n");
 556                 usage(stderr);
 557                 ret = CMD_ERROR;
 558                 goto end;
 559         }
 560
 561         if (!opt_session_name) {
 562                 session_name = get_session_name();
 563                 if (session_name == NULL) {
 564                         ret = CMD_ERROR;
 565                         goto end;
 566                 }
 567         } else {
 568                 session_name = opt_session_name;
 569         }
 570
 571         ret = enable_events(session_name);
 572
 573 end:
 574         if (opt_session_name == NULL) {
 575                 free(session_name);
 576         }
 577
 578         poptFreeContext(pc);
 579         return ret;
 580 }