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 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 #include <inttypes.h>
  27 #include <ctype.h>
  28
  29 #include "../command.h"
  30 #include <src/common/sessiond-comm/sessiond-comm.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 static char *opt_filter;
  45 #if 0
  46 /* Not implemented yet */
  47 static char *opt_cmd_name;
  48 static pid_t opt_pid;
  49 #endif
  50
  51 enum {
  52         OPT_HELP = 1,
  53         OPT_TRACEPOINT,
  54         OPT_PROBE,
  55         OPT_FUNCTION,
  56         OPT_FUNCTION_ENTRY,
  57         OPT_SYSCALL,
  58         OPT_USERSPACE,
  59         OPT_LOGLEVEL,
  60         OPT_LOGLEVEL_ONLY,
  61         OPT_LIST_OPTIONS,
  62         OPT_FILTER,
  63 };
  64
  65 static struct lttng_handle *handle;
  66
  67 static struct poptOption long_options[] = {
  68         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  69         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  70         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  71         {"all",            'a', POPT_ARG_VAL, &opt_enable_all, 1, 0, 0},
  72         {"channel",        'c', POPT_ARG_STRING, &opt_channel_name, 0, 0, 0},
  73         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  74         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  75         {"tracepoint",     0,   POPT_ARG_NONE, 0, OPT_TRACEPOINT, 0, 0},
  76         {"probe",          0,   POPT_ARG_STRING, &opt_probe, OPT_PROBE, 0, 0},
  77         {"function",       0,   POPT_ARG_STRING, &opt_function, OPT_FUNCTION, 0, 0},
  78 #if 0
  79         /*
  80          * Currently removed from lttng kernel tracer. Removed from
  81          * lttng UI to discourage its use.
  82          */
  83         {"function:entry", 0,   POPT_ARG_STRING, &opt_function_entry_symbol, OPT_FUNCTION_ENTRY, 0, 0},
  84 #endif
  85         {"syscall",        0,   POPT_ARG_NONE, 0, OPT_SYSCALL, 0, 0},
  86         {"loglevel",       0,     POPT_ARG_STRING, 0, OPT_LOGLEVEL, 0, 0},
  87         {"loglevel-only",  0,     POPT_ARG_STRING, 0, OPT_LOGLEVEL_ONLY, 0, 0},
  88         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  89         {"filter",         'f', POPT_ARG_STRING, &opt_filter, OPT_FILTER, 0, 0},
  90         {0, 0, 0, 0, 0, 0, 0}
  91 };
  92
  93 /*
  94  * usage
  95  */
  96 static void usage(FILE *ofp)
  97 {
  98         fprintf(ofp, "usage: lttng enable-event NAME[,NAME2,...] [-k|-u] [OPTIONS] \n");
  99         fprintf(ofp, "\n");
 100         fprintf(ofp, "Options:\n");
 101         fprintf(ofp, "  -h, --help               Show this help\n");
 102         fprintf(ofp, "      --list-options       Simple listing of options\n");
 103         fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
 104         fprintf(ofp, "  -c, --channel NAME       Apply to this channel\n");
 105         fprintf(ofp, "  -a, --all                Enable all tracepoints and syscalls\n");
 106         fprintf(ofp, "  -k, --kernel             Apply for the kernel tracer\n");
 107         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
 108         fprintf(ofp, "\n");
 109         fprintf(ofp, "Event options:\n");
 110         fprintf(ofp, "    --tracepoint           Tracepoint event (default)\n");
 111         fprintf(ofp, "                           - userspace tracer supports wildcards at end of string.\n");
 112         fprintf(ofp, "                             Don't forget to quote to deal with bash expansion.\n");
 113         fprintf(ofp, "                             e.g.:\n");
 114         fprintf(ofp, "                               \"*\"\n");
 115         fprintf(ofp, "                               \"app_component:na*\"\n");
 116         fprintf(ofp, "    --probe [addr | symbol | symbol+offset]\n");
 117         fprintf(ofp, "                           Dynamic probe.\n");
 118         fprintf(ofp, "                           Addr and offset can be octal (0NNN...),\n");
 119         fprintf(ofp, "                           decimal (NNN...) or hexadecimal (0xNNN...)\n");
 120         fprintf(ofp, "    --function [addr | symbol | symbol+offset]\n");
 121         fprintf(ofp, "                           Dynamic function entry/return probe.\n");
 122         fprintf(ofp, "                           Addr and offset can be octal (0NNN...),\n");
 123         fprintf(ofp, "                           decimal (NNN...) or hexadecimal (0xNNN...)\n");
 124 #if 0
 125         fprintf(ofp, "    --function:entry symbol\n");
 126         fprintf(ofp, "                           Function tracer event\n");
 127 #endif
 128         fprintf(ofp, "    --syscall              System call event\n");
 129         fprintf(ofp, "\n");
 130         fprintf(ofp, "    --loglevel name\n");
 131         fprintf(ofp, "                           Tracepoint loglevel range from 0 to loglevel\n");
 132         fprintf(ofp, "    --loglevel-only name\n");
 133         fprintf(ofp, "                           Tracepoint loglevel (only this loglevel)\n");
 134         fprintf(ofp, "\n");
 135         fprintf(ofp, "                           The loglevel or loglevel-only options should be\n");
 136         fprintf(ofp, "                           combined with a tracepoint name or tracepoint\n");
 137         fprintf(ofp, "                           wildcard.\n");
 138         fprintf(ofp, "                           Available loglevels:\n");
 139         fprintf(ofp, "                                              (higher value is more verbose)\n");
 140         fprintf(ofp, "                               TRACE_EMERG          = 0\n");
 141         fprintf(ofp, "                               TRACE_ALERT          = 1\n");
 142         fprintf(ofp, "                               TRACE_CRIT           = 2\n");
 143         fprintf(ofp, "                               TRACE_ERR            = 3\n");
 144         fprintf(ofp, "                               TRACE_WARNING        = 4\n");
 145         fprintf(ofp, "                               TRACE_NOTICE         = 5\n");
 146         fprintf(ofp, "                               TRACE_INFO           = 6\n");
 147         fprintf(ofp, "                               TRACE_DEBUG_SYSTEM   = 7\n");
 148         fprintf(ofp, "                               TRACE_DEBUG_PROGRAM  = 8\n");
 149         fprintf(ofp, "                               TRACE_DEBUG_PROCESS  = 9\n");
 150         fprintf(ofp, "                               TRACE_DEBUG_MODULE   = 10\n");
 151         fprintf(ofp, "                               TRACE_DEBUG_UNIT     = 11\n");
 152         fprintf(ofp, "                               TRACE_DEBUG_FUNCTION = 12\n");
 153         fprintf(ofp, "                               TRACE_DEBUG_LINE     = 13\n");
 154         fprintf(ofp, "                               TRACE_DEBUG          = 14\n");
 155         fprintf(ofp, "                               (shortcuts such as \"system\" are allowed)\n");
 156         fprintf(ofp, "    --filter \'expression\'\n");
 157         fprintf(ofp, "                           Filter expression on event fields,\n");
 158         fprintf(ofp, "                           event recording depends on evaluation.\n");
 159         fprintf(ofp, "                           Only specify on first activation of\n");
 160         fprintf(ofp, "                           a given event within a session.\n");
 161         fprintf(ofp, "                           Filter only allowed when enabling\n");
 162         fprintf(ofp, "                           events within a session before tracing\n");
 163         fprintf(ofp, "                           is started. If the filter fails to link\n");
 164         fprintf(ofp, "                           with the event within the traced domain,\n");
 165         fprintf(ofp, "                           the event will be discarded. Currently,\n");
 166         fprintf(ofp, "                           filter is only implemented for the user-space\n");
 167         fprintf(ofp, "                           tracer.\n");
 168         fprintf(ofp, "                           Expression examples:.\n");
 169         fprintf(ofp, "                           \n");
 170         fprintf(ofp, "                           'intfield > 500 && intfield < 503'\n");
 171         fprintf(ofp, "                           '(stringfield == \"test\" || intfield != 10) && intfield > 33'\n");
 172         fprintf(ofp, "                           'doublefield > 1.1 && intfield < 5.3'\n");
 173         fprintf(ofp, "                           \n");
 174         fprintf(ofp, "                           Wildcards are allowed at the end of strings:\n");
 175         fprintf(ofp, "                           'seqfield1 == \"te*\"'\n");
 176         fprintf(ofp, "                           In string literals, the escape character is '\\'.\n");
 177         fprintf(ofp, "                           Use '\\*' for the '*' character, and '\\\\' for\n");
 178         fprintf(ofp, "                           the '\\' character.\n");
 179         fprintf(ofp, "\n");
 180 }
 181
 182 /*
 183  * Parse probe options.
 184  */
 185 static int parse_probe_opts(struct lttng_event *ev, char *opt)
 186 {
 187         int ret;
 188         char s_hex[19];
 189         char name[LTTNG_SYMBOL_NAME_LEN];
 190
 191         if (opt == NULL) {
 192                 ret = -1;
 193                 goto end;
 194         }
 195
 196         /* Check for symbol+offset */
 197         ret = sscanf(opt, "%[^'+']+%s", name, s_hex);
 198         if (ret == 2) {
 199                 strncpy(ev->attr.probe.symbol_name, name, LTTNG_SYMBOL_NAME_LEN);
 200                 ev->attr.probe.symbol_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 201                 DBG("probe symbol %s", ev->attr.probe.symbol_name);
 202                 if (strlen(s_hex) == 0) {
 203                         ERR("Invalid probe offset %s", s_hex);
 204                         ret = -1;
 205                         goto end;
 206                 }
 207                 ev->attr.probe.offset = strtoul(s_hex, NULL, 0);
 208                 DBG("probe offset %" PRIu64, ev->attr.probe.offset);
 209                 ev->attr.probe.addr = 0;
 210                 goto end;
 211         }
 212
 213         /* Check for symbol */
 214         if (isalpha(name[0])) {
 215                 ret = sscanf(opt, "%s", name);
 216                 if (ret == 1) {
 217                         strncpy(ev->attr.probe.symbol_name, name, LTTNG_SYMBOL_NAME_LEN);
 218                         ev->attr.probe.symbol_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 219                         DBG("probe symbol %s", ev->attr.probe.symbol_name);
 220                         ev->attr.probe.offset = 0;
 221                         DBG("probe offset %" PRIu64, ev->attr.probe.offset);
 222                         ev->attr.probe.addr = 0;
 223                         goto end;
 224                 }
 225         }
 226
 227         /* Check for address */
 228         ret = sscanf(opt, "%s", s_hex);
 229         if (ret > 0) {
 230                 if (strlen(s_hex) == 0) {
 231                         ERR("Invalid probe address %s", s_hex);
 232                         ret = -1;
 233                         goto end;
 234                 }
 235                 ev->attr.probe.addr = strtoul(s_hex, NULL, 0);
 236                 DBG("probe addr %" PRIu64, ev->attr.probe.addr);
 237                 ev->attr.probe.offset = 0;
 238                 memset(ev->attr.probe.symbol_name, 0, LTTNG_SYMBOL_NAME_LEN);
 239                 goto end;
 240         }
 241
 242         /* No match */
 243         ret = -1;
 244
 245 end:
 246         return ret;
 247 }
 248
 249 /*
 250  * Maps loglevel from string to value
 251  */
 252 static
 253 int loglevel_str_to_value(const char *inputstr)
 254 {
 255         int i = 0;
 256         char str[LTTNG_SYMBOL_NAME_LEN];
 257
 258         while (inputstr[i] != '\0' && i < LTTNG_SYMBOL_NAME_LEN) {
 259                 str[i] = toupper(inputstr[i]);
 260                 i++;
 261         }
 262         str[i] = '\0';
 263         if (!strcmp(str, "TRACE_EMERG") || !strcmp(str, "EMERG")) {
 264                 return LTTNG_LOGLEVEL_EMERG;
 265         } else if (!strcmp(str, "TRACE_ALERT") || !strcmp(str, "ALERT")) {
 266                 return LTTNG_LOGLEVEL_ALERT;
 267         } else if (!strcmp(str, "TRACE_CRIT") || !strcmp(str, "CRIT")) {
 268                 return LTTNG_LOGLEVEL_CRIT;
 269         } else if (!strcmp(str, "TRACE_ERR") || !strcmp(str, "ERR")) {
 270                 return LTTNG_LOGLEVEL_ERR;
 271         } else if (!strcmp(str, "TRACE_WARNING") || !strcmp(str, "WARNING")) {
 272                 return LTTNG_LOGLEVEL_WARNING;
 273         } else if (!strcmp(str, "TRACE_NOTICE") || !strcmp(str, "NOTICE")) {
 274                 return LTTNG_LOGLEVEL_NOTICE;
 275         } else if (!strcmp(str, "TRACE_INFO") || !strcmp(str, "INFO")) {
 276                 return LTTNG_LOGLEVEL_INFO;
 277         } else if (!strcmp(str, "TRACE_DEBUG_SYSTEM") || !strcmp(str, "DEBUG_SYSTEM") || !strcmp(str, "SYSTEM")) {
 278                 return LTTNG_LOGLEVEL_DEBUG_SYSTEM;
 279         } else if (!strcmp(str, "TRACE_DEBUG_PROGRAM") || !strcmp(str, "DEBUG_PROGRAM") || !strcmp(str, "PROGRAM")) {
 280                 return LTTNG_LOGLEVEL_DEBUG_PROGRAM;
 281         } else if (!strcmp(str, "TRACE_DEBUG_PROCESS") || !strcmp(str, "DEBUG_PROCESS") || !strcmp(str, "PROCESS")) {
 282                 return LTTNG_LOGLEVEL_DEBUG_PROCESS;
 283         } else if (!strcmp(str, "TRACE_DEBUG_MODULE") || !strcmp(str, "DEBUG_MODULE") || !strcmp(str, "MODULE")) {
 284                 return LTTNG_LOGLEVEL_DEBUG_MODULE;
 285         } else if (!strcmp(str, "TRACE_DEBUG_UNIT") || !strcmp(str, "DEBUG_UNIT") || !strcmp(str, "UNIT")) {
 286                 return LTTNG_LOGLEVEL_DEBUG_UNIT;
 287         } else if (!strcmp(str, "TRACE_DEBUG_FUNCTION") || !strcmp(str, "DEBUG_FUNCTION") || !strcmp(str, "FUNCTION")) {
 288                 return LTTNG_LOGLEVEL_DEBUG_FUNCTION;
 289         } else if (!strcmp(str, "TRACE_DEBUG_LINE") || !strcmp(str, "DEBUG_LINE") || !strcmp(str, "LINE")) {
 290                 return LTTNG_LOGLEVEL_DEBUG_LINE;
 291         } else if (!strcmp(str, "TRACE_DEBUG") || !strcmp(str, "DEBUG")) {
 292                 return LTTNG_LOGLEVEL_DEBUG;
 293         } else {
 294                 return -1;
 295         }
 296 }
 297
 298 /*
 299  * Enabling event using the lttng API.
 300  */
 301 static int enable_events(char *session_name)
 302 {
 303         int err, ret = CMD_SUCCESS, warn = 0;
 304         char *event_name, *channel_name = NULL;
 305         struct lttng_event ev;
 306         struct lttng_domain dom;
 307
 308         memset(&ev, 0, sizeof(ev));
 309         memset(&dom, 0, sizeof(dom));
 310
 311         if (opt_kernel) {
 312                 if (opt_filter) {
 313                         ERR("Filter not implement for kernel tracing yet");
 314                         ret = CMD_ERROR;
 315                         goto error;
 316                 }
 317         }
 318
 319         /* Create lttng domain */
 320         if (opt_kernel) {
 321                 dom.type = LTTNG_DOMAIN_KERNEL;
 322         } else if (opt_userspace) {
 323                 dom.type = LTTNG_DOMAIN_UST;
 324         } else {
 325                 ERR("Please specify a tracer (-k/--kernel or -u/--userspace)");
 326                 ret = CMD_ERROR;
 327                 goto error;
 328         }
 329
 330         if (opt_channel_name == NULL) {
 331                 err = asprintf(&channel_name, DEFAULT_CHANNEL_NAME);
 332                 if (err < 0) {
 333                         ret = CMD_FATAL;
 334                         goto error;
 335                 }
 336         } else {
 337                 channel_name = opt_channel_name;
 338         }
 339
 340         handle = lttng_create_handle(session_name, &dom);
 341         if (handle == NULL) {
 342                 ret = -1;
 343                 goto error;
 344         }
 345
 346         if (opt_enable_all) {
 347                 /* Default setup for enable all */
 348                 if (opt_kernel) {
 349                         ev.type = opt_event_type;
 350                         ev.name[0] = '\0';
 351                         /* kernel loglevels not implemented */
 352                         ev.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
 353                 } else {
 354                         ev.type = LTTNG_EVENT_TRACEPOINT;
 355                         strcpy(ev.name, "*");
 356                         ev.loglevel_type = opt_loglevel_type;
 357                         if (opt_loglevel) {
 358                                 ev.loglevel = loglevel_str_to_value(opt_loglevel);
 359                                 if (ev.loglevel == -1) {
 360                                         ERR("Unknown loglevel %s", opt_loglevel);
 361                                         ret = -LTTNG_ERR_INVALID;
 362                                         goto error;
 363                                 }
 364                         } else {
 365                                 ev.loglevel = -1;
 366                         }
 367                 }
 368
 369                 ret = lttng_enable_event(handle, &ev, channel_name);
 370                 if (ret < 0) {
 371                         switch (-ret) {
 372                         case LTTNG_ERR_KERN_EVENT_EXIST:
 373                                 WARN("Kernel events already enabled (channel %s, session %s)",
 374                                                 channel_name, session_name);
 375                                 break;
 376                         default:
 377                                 ERR("Events: %s (channel %s, session %s)",
 378                                                 lttng_strerror(ret), channel_name, session_name);
 379                                 break;
 380                         }
 381                         goto end;
 382                 }
 383
 384                 switch (opt_event_type) {
 385                 case LTTNG_EVENT_TRACEPOINT:
 386                         if (opt_loglevel) {
 387                                 MSG("All %s tracepoints are enabled in channel %s for loglevel %s",
 388                                                 opt_kernel ? "kernel" : "UST", channel_name,
 389                                                 opt_loglevel);
 390                         } else {
 391                                 MSG("All %s tracepoints are enabled in channel %s",
 392                                                 opt_kernel ? "kernel" : "UST", channel_name);
 393
 394                         }
 395                         break;
 396                 case LTTNG_EVENT_SYSCALL:
 397                         if (opt_kernel) {
 398                                 MSG("All kernel system calls are enabled in channel %s",
 399                                                 channel_name);
 400                         }
 401                         break;
 402                 case LTTNG_EVENT_ALL:
 403                         if (opt_loglevel) {
 404                                 MSG("All %s events are enabled in channel %s for loglevel %s",
 405                                                 opt_kernel ? "kernel" : "UST", channel_name,
 406                                                 opt_loglevel);
 407                         } else {
 408                                 MSG("All %s events are enabled in channel %s",
 409                                                 opt_kernel ? "kernel" : "UST", channel_name);
 410                         }
 411                         break;
 412                 default:
 413                         /*
 414                          * We should not be here since lttng_enable_event should have
 415                          * failed on the event type.
 416                          */
 417                         goto error;
 418                 }
 419                 if (opt_filter) {
 420                         ret = lttng_set_event_filter(handle, ev.name, channel_name,
 421                                                 opt_filter);
 422                         if (ret < 0) {
 423                                 switch (-ret) {
 424                                 case LTTNG_ERR_FILTER_EXIST:
 425                                         WARN("Filter on events is already enabled"
 426                                                         " (channel %s, session %s)",
 427                                                 channel_name, session_name);
 428                                         break;
 429                                 case LTTNG_ERR_FILTER_INVAL:
 430                                 case LTTNG_ERR_FILTER_NOMEM:
 431                                         ERR("%s", lttng_strerror(ret));
 432                                 default:
 433                                         ERR("Setting filter: '%s'", opt_filter);
 434                                         /*
 435                                          * The event was successfully enabled before so when
 436                                          * failing to set a filter, disable the event. This has
 437                                          * been discussed in bug #343 on why we do that.
 438                                          */
 439                                         err = lttng_disable_event(handle, ev.name, channel_name);
 440                                         if (err < 0) {
 441                                                 ERR("Disabling all events after filter error: %s",
 442                                                                 lttng_strerror(err));
 443                                         } else {
 444                                                 WARN("All events of channel %s have been disabled due "
 445                                                                 "to a filter error", channel_name);
 446                                         }
 447                                         break;
 448                                 }
 449                                 goto error;
 450                         } else {
 451                                 MSG("Filter '%s' successfully set", opt_filter);
 452                         }
 453                 }
 454                 goto end;
 455         }
 456
 457         /* Strip event list */
 458         event_name = strtok(opt_event_list, ",");
 459         while (event_name != NULL) {
 460                 /* Copy name and type of the event */
 461                 strncpy(ev.name, event_name, LTTNG_SYMBOL_NAME_LEN);
 462                 ev.name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 463                 ev.type = opt_event_type;
 464
 465                 /* Kernel tracer action */
 466                 if (opt_kernel) {
 467                         DBG("Enabling kernel event %s for channel %s",
 468                                         event_name, channel_name);
 469
 470                         switch (opt_event_type) {
 471                         case LTTNG_EVENT_ALL:   /* Default behavior is tracepoint */
 472                                 ev.type = LTTNG_EVENT_TRACEPOINT;
 473                                 /* Fall-through */
 474                         case LTTNG_EVENT_TRACEPOINT:
 475                                 break;
 476                         case LTTNG_EVENT_PROBE:
 477                                 ret = parse_probe_opts(&ev, opt_probe);
 478                                 if (ret < 0) {
 479                                         ERR("Unable to parse probe options");
 480                                         ret = 0;
 481                                         goto error;
 482                                 }
 483                                 break;
 484                         case LTTNG_EVENT_FUNCTION:
 485                                 ret = parse_probe_opts(&ev, opt_function);
 486                                 if (ret < 0) {
 487                                         ERR("Unable to parse function probe options");
 488                                         ret = 0;
 489                                         goto error;
 490                                 }
 491                                 break;
 492                         case LTTNG_EVENT_FUNCTION_ENTRY:
 493                                 strncpy(ev.attr.ftrace.symbol_name, opt_function_entry_symbol,
 494                                                 LTTNG_SYMBOL_NAME_LEN);
 495                                 ev.attr.ftrace.symbol_name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 496                                 break;
 497                         case LTTNG_EVENT_SYSCALL:
 498                                 MSG("per-syscall selection not supported yet. Use \"-a\" "
 499                                                 "for all syscalls.");
 500                         default:
 501                                 ret = CMD_UNDEFINED;
 502                                 goto error;
 503                         }
 504
 505                         if (opt_loglevel) {
 506                                 MSG("Kernel loglevels are not supported.");
 507                                 ret = CMD_UNDEFINED;
 508                                 goto error;
 509                         }
 510
 511                         /* kernel loglevels not implemented */
 512                         ev.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
 513                 } else if (opt_userspace) {             /* User-space tracer action */
 514 #if 0
 515                         if (opt_cmd_name != NULL || opt_pid) {
 516                                 MSG("Only supporting tracing all UST processes (-u) for now.");
 517                                 ret = CMD_UNDEFINED;
 518                                 goto error;
 519                         }
 520 #endif
 521
 522                         DBG("Enabling UST event %s for channel %s, loglevel %s", event_name,
 523                                         channel_name, opt_loglevel ? : "<all>");
 524
 525                         switch (opt_event_type) {
 526                         case LTTNG_EVENT_ALL:   /* Default behavior is tracepoint */
 527                                 /* Fall-through */
 528                         case LTTNG_EVENT_TRACEPOINT:
 529                                 /* Copy name and type of the event */
 530                                 ev.type = LTTNG_EVENT_TRACEPOINT;
 531                                 strncpy(ev.name, event_name, LTTNG_SYMBOL_NAME_LEN);
 532                                 ev.name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 533                                 break;
 534                         case LTTNG_EVENT_PROBE:
 535                         case LTTNG_EVENT_FUNCTION:
 536                         case LTTNG_EVENT_FUNCTION_ENTRY:
 537                         case LTTNG_EVENT_SYSCALL:
 538                         default:
 539                                 ERR("Event type not available for user-space tracing");
 540                                 ret = CMD_UNDEFINED;
 541                                 goto error;
 542                         }
 543
 544                         ev.loglevel_type = opt_loglevel_type;
 545                         if (opt_loglevel) {
 546                                 ev.loglevel = loglevel_str_to_value(opt_loglevel);
 547                                 if (ev.loglevel == -1) {
 548                                         ERR("Unknown loglevel %s", opt_loglevel);
 549                                         ret = -LTTNG_ERR_INVALID;
 550                                         goto error;
 551                                 }
 552                         } else {
 553                                 ev.loglevel = -1;
 554                         }
 555                 } else {
 556                         ERR("Please specify a tracer (-k/--kernel or -u/--userspace)");
 557                         ret = CMD_ERROR;
 558                         goto error;
 559                 }
 560
 561                 ret = lttng_enable_event(handle, &ev, channel_name);
 562                 if (ret < 0) {
 563                         /* Turn ret to positive value to handle the positive error code */
 564                         switch (-ret) {
 565                         case LTTNG_ERR_KERN_EVENT_EXIST:
 566                                 WARN("Kernel event %s already enabled (channel %s, session %s)",
 567                                                 event_name, channel_name, session_name);
 568                                 break;
 569                         default:
 570                                 ERR("Event %s: %s (channel %s, session %s)", event_name,
 571                                                 lttng_strerror(ret), channel_name, session_name);
 572                                 break;
 573                         }
 574                         warn = 1;
 575                 } else {
 576                         MSG("%s event %s created in channel %s",
 577                                         opt_kernel ? "kernel": "UST", event_name, channel_name);
 578                 }
 579                 if (opt_filter) {
 580                         ret = lttng_set_event_filter(handle, ev.name, channel_name,
 581                                         opt_filter);
 582                         if (ret < 0) {
 583                                 switch (-ret) {
 584                                 case LTTNG_ERR_FILTER_EXIST:
 585                                         WARN("Filter on event %s is already enabled"
 586                                                         " (channel %s, session %s)",
 587                                                 event_name, channel_name, session_name);
 588                                         break;
 589                                 case LTTNG_ERR_FILTER_INVAL:
 590                                 case LTTNG_ERR_FILTER_NOMEM:
 591                                         ERR("%s", lttng_strerror(ret));
 592                                 default:
 593                                         ERR("Setting filter for event %s: '%s'", ev.name,
 594                                                         opt_filter);
 595                                         /*
 596                                          * The event was successfully enabled before so when
 597                                          * failing to set a filter, disable the event. This has
 598                                          * been discussed in bug #343 on why we do that.
 599                                          */
 600                                         err = lttng_disable_event(handle, ev.name, channel_name);
 601                                         if (err < 0) {
 602                                                 ERR("Disabling event %s after filter error: %s",
 603                                                                 ev.name, lttng_strerror(err));
 604                                         } else {
 605                                                 WARN("Event %s of channel %s has been disabled due "
 606                                                                 "to a filter error", ev.name, channel_name);
 607                                         }
 608                                         break;
 609                                 }
 610                                 goto error;
 611                         } else {
 612                                 MSG("Filter '%s' successfully set", opt_filter);
 613                         }
 614                 }
 615
 616                 /* Next event */
 617                 event_name = strtok(NULL, ",");
 618         }
 619
 620 end:
 621 error:
 622         if (warn) {
 623                 ret = CMD_WARNING;
 624         }
 625         if (opt_channel_name == NULL) {
 626                 free(channel_name);
 627         }
 628         lttng_destroy_handle(handle);
 629
 630         return ret;
 631 }
 632
 633 /*
 634  * Add event to trace session
 635  */
 636 int cmd_enable_events(int argc, const char **argv)
 637 {
 638         int opt, ret = CMD_SUCCESS;
 639         static poptContext pc;
 640         char *session_name = NULL;
 641
 642         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 643         poptReadDefaultConfig(pc, 0);
 644
 645         /* Default event type */
 646         opt_event_type = LTTNG_EVENT_ALL;
 647
 648         while ((opt = poptGetNextOpt(pc)) != -1) {
 649                 switch (opt) {
 650                 case OPT_HELP:
 651                         usage(stdout);
 652                         goto end;
 653                 case OPT_TRACEPOINT:
 654                         opt_event_type = LTTNG_EVENT_TRACEPOINT;
 655                         break;
 656                 case OPT_PROBE:
 657                         opt_event_type = LTTNG_EVENT_PROBE;
 658                         break;
 659                 case OPT_FUNCTION:
 660                         opt_event_type = LTTNG_EVENT_FUNCTION;
 661                         break;
 662                 case OPT_FUNCTION_ENTRY:
 663                         opt_event_type = LTTNG_EVENT_FUNCTION_ENTRY;
 664                         break;
 665                 case OPT_SYSCALL:
 666                         opt_event_type = LTTNG_EVENT_SYSCALL;
 667                         break;
 668                 case OPT_USERSPACE:
 669                         opt_userspace = 1;
 670                         break;
 671                 case OPT_LOGLEVEL:
 672                         opt_loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
 673                         opt_loglevel = poptGetOptArg(pc);
 674                         break;
 675                 case OPT_LOGLEVEL_ONLY:
 676                         opt_loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
 677                         opt_loglevel = poptGetOptArg(pc);
 678                         break;
 679                 case OPT_LIST_OPTIONS:
 680                         list_cmd_options(stdout, long_options);
 681                         goto end;
 682                 case OPT_FILTER:
 683                         break;
 684                 default:
 685                         usage(stderr);
 686                         ret = CMD_UNDEFINED;
 687                         goto end;
 688                 }
 689         }
 690
 691         opt_event_list = (char*) poptGetArg(pc);
 692         if (opt_event_list == NULL && opt_enable_all == 0) {
 693                 ERR("Missing event name(s).\n");
 694                 usage(stderr);
 695                 ret = CMD_ERROR;
 696                 goto end;
 697         }
 698
 699         if (!opt_session_name) {
 700                 session_name = get_session_name();
 701                 if (session_name == NULL) {
 702                         ret = CMD_ERROR;
 703                         goto end;
 704                 }
 705         } else {
 706                 session_name = opt_session_name;
 707         }
 708
 709         ret = enable_events(session_name);
 710
 711 end:
 712         if (opt_session_name == NULL) {
 713                 free(session_name);
 714         }
 715
 716         poptFreeContext(pc);
 717         return ret;
 718 }