src/bin/lttng/commands/enable_channels.c

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <popt.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16 #include <inttypes.h>
  17 #include <assert.h>
  18 #include <ctype.h>
  19
  20 #include <common/sessiond-comm/sessiond-comm.h>
  21 #include <common/utils.h>
  22 #include <common/mi-lttng.h>
  23
  24 #include "../command.h"
  25 #include "../utils.h"
  26
  27
  28 static struct lttng_channel chan_opts;
  29 static int opt_kernel;
  30 static char *opt_session_name;
  31 static int opt_userspace;
  32 static char *opt_output;
  33 static int opt_buffer_uid;
  34 static int opt_buffer_pid;
  35 static int opt_buffer_global;
  36 static struct {
  37         bool set;
  38         uint64_t interval;
  39 } opt_monitor_timer;
  40 static struct {
  41         bool set;
  42         int64_t value;
  43 } opt_blocking_timeout;
  44
  45 static struct mi_writer *writer;
  46
  47 #ifdef LTTNG_EMBED_HELP
  48 static const char help_msg[] =
  49 #include <lttng-enable-channel.1.h>
  50 ;
  51 #endif
  52
  53 enum {
  54         OPT_HELP = 1,
  55         OPT_DISCARD,
  56         OPT_OVERWRITE,
  57         OPT_SUBBUF_SIZE,
  58         OPT_NUM_SUBBUF,
  59         OPT_SWITCH_TIMER,
  60         OPT_MONITOR_TIMER,
  61         OPT_READ_TIMER,
  62         OPT_USERSPACE,
  63         OPT_LIST_OPTIONS,
  64         OPT_TRACEFILE_SIZE,
  65         OPT_TRACEFILE_COUNT,
  66         OPT_BLOCKING_TIMEOUT,
  67 };
  68
  69 static struct lttng_handle *handle;
  70
  71 const char *output_mmap = "mmap";
  72 const char *output_splice = "splice";
  73
  74 static struct poptOption long_options[] = {
  75         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  76         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  77         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  78         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  79         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  80         {"discard",        0,   POPT_ARG_NONE, 0, OPT_DISCARD, 0, 0},
  81         {"overwrite",      0,   POPT_ARG_NONE, 0, OPT_OVERWRITE, 0, 0},
  82         {"subbuf-size",    0,   POPT_ARG_STRING, 0, OPT_SUBBUF_SIZE, 0, 0},
  83         {"num-subbuf",     0,   POPT_ARG_INT, 0, OPT_NUM_SUBBUF, 0, 0},
  84         {"switch-timer",   0,   POPT_ARG_INT, 0, OPT_SWITCH_TIMER, 0, 0},
  85         {"monitor-timer",  0,   POPT_ARG_INT, 0, OPT_MONITOR_TIMER, 0, 0},
  86         {"read-timer",     0,   POPT_ARG_INT, 0, OPT_READ_TIMER, 0, 0},
  87         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  88         {"output",         0,   POPT_ARG_STRING, &opt_output, 0, 0, 0},
  89         {"buffers-uid",    0,   POPT_ARG_VAL, &opt_buffer_uid, 1, 0, 0},
  90         {"buffers-pid",    0,   POPT_ARG_VAL, &opt_buffer_pid, 1, 0, 0},
  91         {"buffers-global", 0,   POPT_ARG_VAL, &opt_buffer_global, 1, 0, 0},
  92         {"tracefile-size", 'C',   POPT_ARG_INT, 0, OPT_TRACEFILE_SIZE, 0, 0},
  93         {"tracefile-count", 'W',   POPT_ARG_INT, 0, OPT_TRACEFILE_COUNT, 0, 0},
  94         {"blocking-timeout",     0,   POPT_ARG_INT, 0, OPT_BLOCKING_TIMEOUT, 0, 0},
  95         {0, 0, 0, 0, 0, 0, 0}
  96 };
  97
  98 /*
  99  * Set default attributes depending on those already defined from the command
 100  * line.
 101  */
 102 static void set_default_attr(struct lttng_domain *dom)
 103 {
 104         struct lttng_channel_attr default_attr;
 105
 106         memset(&default_attr, 0, sizeof(default_attr));
 107
 108         /* Set attributes */
 109         lttng_channel_set_default_attr(dom, &default_attr);
 110
 111         if (chan_opts.attr.overwrite == -1) {
 112                 chan_opts.attr.overwrite = default_attr.overwrite;
 113         }
 114         if (chan_opts.attr.subbuf_size == -1) {
 115                 chan_opts.attr.subbuf_size = default_attr.subbuf_size;
 116         }
 117         if (chan_opts.attr.num_subbuf == -1) {
 118                 chan_opts.attr.num_subbuf = default_attr.num_subbuf;
 119         }
 120         if (chan_opts.attr.switch_timer_interval == -1) {
 121                 chan_opts.attr.switch_timer_interval = default_attr.switch_timer_interval;
 122         }
 123         if (chan_opts.attr.read_timer_interval == -1) {
 124                 chan_opts.attr.read_timer_interval = default_attr.read_timer_interval;
 125         }
 126         if ((int) chan_opts.attr.output == -1) {
 127                 chan_opts.attr.output = default_attr.output;
 128         }
 129         if (chan_opts.attr.tracefile_count == -1) {
 130                 chan_opts.attr.tracefile_count = default_attr.tracefile_count;
 131         }
 132         if (chan_opts.attr.tracefile_size == -1) {
 133                 chan_opts.attr.tracefile_size = default_attr.tracefile_size;
 134         }
 135 }
 136
 137 /*
 138  * Adding channel using the lttng API.
 139  */
 140 static int enable_channel(char *session_name, char *channel_list)
 141 {
 142         struct lttng_channel *channel = NULL;
 143         int ret = CMD_SUCCESS, warn = 0, error = 0, success = 0;
 144         char *channel_name;
 145         struct lttng_domain dom;
 146
 147         memset(&dom, 0, sizeof(dom));
 148
 149         /* Validate options. */
 150         if (opt_kernel) {
 151                 if (opt_blocking_timeout.set) {
 152                         ERR("Retry timeout option not supported for kernel domain (-k)");
 153                         ret = CMD_ERROR;
 154                         goto error;
 155                 }
 156         }
 157
 158         /* Create lttng domain */
 159         if (opt_kernel) {
 160                 dom.type = LTTNG_DOMAIN_KERNEL;
 161                 dom.buf_type = LTTNG_BUFFER_GLOBAL;
 162                 if (opt_buffer_uid || opt_buffer_pid) {
 163                         ERR("Buffer type not supported for domain -k");
 164                         ret = CMD_ERROR;
 165                         goto error;
 166                 }
 167         } else if (opt_userspace) {
 168                 dom.type = LTTNG_DOMAIN_UST;
 169                 if (opt_buffer_pid) {
 170                         dom.buf_type = LTTNG_BUFFER_PER_PID;
 171                 } else {
 172                         if (opt_buffer_global) {
 173                                 ERR("Buffer type not supported for domain -u");
 174                                 ret = CMD_ERROR;
 175                                 goto error;
 176                         }
 177                         dom.buf_type = LTTNG_BUFFER_PER_UID;
 178                 }
 179         } else {
 180                 /* Checked by the caller. */
 181                 assert(0);
 182         }
 183
 184         set_default_attr(&dom);
 185
 186         if (chan_opts.attr.tracefile_size == 0 && chan_opts.attr.tracefile_count) {
 187                 ERR("Missing option --tracefile-size. "
 188                                 "A file count without a size won't do anything.");
 189                 ret = CMD_ERROR;
 190                 goto error;
 191         }
 192
 193         if ((chan_opts.attr.tracefile_size > 0) &&
 194                         (chan_opts.attr.tracefile_size < chan_opts.attr.subbuf_size)) {
 195                 WARN("Tracefile size rounded up from (%" PRIu64 ") to subbuffer size (%" PRIu64 ")",
 196                                 chan_opts.attr.tracefile_size, chan_opts.attr.subbuf_size);
 197                 chan_opts.attr.tracefile_size = chan_opts.attr.subbuf_size;
 198         }
 199
 200         /* Setting channel output */
 201         if (opt_output) {
 202                 if (!strncmp(output_mmap, opt_output, strlen(output_mmap))) {
 203                         chan_opts.attr.output = LTTNG_EVENT_MMAP;
 204                 } else if (!strncmp(output_splice, opt_output, strlen(output_splice))) {
 205                         chan_opts.attr.output = LTTNG_EVENT_SPLICE;
 206                 } else {
 207                         ERR("Unknown output type %s. Possible values are: %s, %s\n",
 208                                         opt_output, output_mmap, output_splice);
 209                         ret = CMD_ERROR;
 210                         goto error;
 211                 }
 212         }
 213
 214         handle = lttng_create_handle(session_name, &dom);
 215         if (handle == NULL) {
 216                 ret = -1;
 217                 goto error;
 218         }
 219
 220         /* Mi open channels element */
 221         if (lttng_opt_mi) {
 222                 assert(writer);
 223                 ret = mi_lttng_channels_open(writer);
 224                 if (ret) {
 225                         ret = CMD_ERROR;
 226                         goto error;
 227                 }
 228         }
 229
 230         /* Strip channel list (format: chan1,chan2,...) */
 231         channel_name = strtok(channel_list, ",");
 232         while (channel_name != NULL) {
 233                 void *extended_ptr;
 234
 235                 /* Validate channel name's length */
 236                 if (strlen(channel_name) >= sizeof(chan_opts.name)) {
 237                         ERR("Channel name is too long (max. %zu characters)",
 238                                         sizeof(chan_opts.name) - 1);
 239                         error = 1;
 240                         goto skip_enable;
 241                 }
 242
 243                 /*
 244                  * A dynamically-allocated channel is used in order to allow
 245                  * the configuration of extended attributes (post-2.9).
 246                  */
 247                 channel = lttng_channel_create(&dom);
 248                 if (!channel) {
 249                         ERR("Unable to create channel object");
 250                         error = 1;
 251                         goto error;
 252                 }
 253
 254                 /* Copy channel name */
 255                 strcpy(channel->name, channel_name);
 256                 channel->enabled = 1;
 257                 extended_ptr = channel->attr.extended.ptr;
 258                 memcpy(&channel->attr, &chan_opts.attr, sizeof(chan_opts.attr));
 259                 channel->attr.extended.ptr = extended_ptr;
 260                 if (opt_monitor_timer.set) {
 261                         ret = lttng_channel_set_monitor_timer_interval(channel,
 262                                         opt_monitor_timer.interval);
 263                         if (ret) {
 264                                 ERR("Failed to set the channel's monitor timer interval");
 265                                 error = 1;
 266                                 goto error;
 267                         }
 268                 }
 269                 if (opt_blocking_timeout.set) {
 270                         ret = lttng_channel_set_blocking_timeout(channel,
 271                                         opt_blocking_timeout.value);
 272                         if (ret) {
 273                                 ERR("Failed to set the channel's blocking timeout");
 274                                 error = 1;
 275                                 goto error;
 276                         }
 277                 }
 278
 279                 DBG("Enabling channel %s", channel_name);
 280
 281                 ret = lttng_enable_channel(handle, channel);
 282                 if (ret < 0) {
 283                         success = 0;
 284                         switch (-ret) {
 285                         case LTTNG_ERR_KERN_CHAN_EXIST:
 286                         case LTTNG_ERR_UST_CHAN_EXIST:
 287                         case LTTNG_ERR_CHAN_EXIST:
 288                                 WARN("Channel %s: %s (session %s)", channel_name,
 289                                                 lttng_strerror(ret), session_name);
 290                                 warn = 1;
 291                                 break;
 292                         case LTTNG_ERR_INVALID_CHANNEL_NAME:
 293                                 ERR("Invalid channel name: \"%s\". "
 294                                     "Channel names may not start with '.', and "
 295                                     "may not contain '/'.", channel_name);
 296                                 error = 1;
 297                                 break;
 298                         default:
 299                                 ERR("Channel %s: %s (session %s)", channel_name,
 300                                                 lttng_strerror(ret), session_name);
 301                                 error = 1;
 302                                 break;
 303                         }
 304                 } else {
 305                         MSG("%s channel %s enabled for session %s",
 306                                         get_domain_str(dom.type), channel_name, session_name);
 307                         success = 1;
 308                 }
 309
 310 skip_enable:
 311                 if (lttng_opt_mi) {
 312                         /* Mi print the channel element and leave it open */
 313                         ret = mi_lttng_channel(writer, channel, 1);
 314                         if (ret) {
 315                                 ret = CMD_ERROR;
 316                                 goto error;
 317                         }
 318
 319                         /* Individual Success ? */
 320                         ret = mi_lttng_writer_write_element_bool(writer,
 321                                         mi_lttng_element_command_success, success);
 322                         if (ret) {
 323                                 ret = CMD_ERROR;
 324                                 goto error;
 325                         }
 326
 327                         /* Close channel element */
 328                         ret = mi_lttng_writer_close_element(writer);
 329                         if (ret) {
 330                                 ret = CMD_ERROR;
 331                                 goto error;
 332                         }
 333                 }
 334
 335                 /* Next channel */
 336                 channel_name = strtok(NULL, ",");
 337                 lttng_channel_destroy(channel);
 338                 channel = NULL;
 339         }
 340
 341         if (lttng_opt_mi) {
 342                 /* Close channels element */
 343                 ret = mi_lttng_writer_close_element(writer);
 344                 if (ret) {
 345                         ret = CMD_ERROR;
 346                         goto error;
 347                 }
 348         }
 349
 350         ret = CMD_SUCCESS;
 351
 352 error:
 353         if (channel) {
 354                 lttng_channel_destroy(channel);
 355         }
 356         /* If more important error happen bypass the warning */
 357         if (!ret && warn) {
 358                 ret = CMD_WARNING;
 359         }
 360         /* If more important error happen bypass the warning */
 361         if (!ret && error) {
 362                 ret = CMD_ERROR;
 363         }
 364
 365         lttng_destroy_handle(handle);
 366
 367         return ret;
 368 }
 369
 370 /*
 371  * Default value for channel configuration.
 372  */
 373 static void init_channel_config(void)
 374 {
 375         /*
 376          * Put -1 everywhere so we can identify those set by the command line and
 377          * those needed to be set by the default values.
 378          */
 379         memset(&chan_opts.attr, -1, sizeof(chan_opts.attr));
 380         chan_opts.attr.extended.ptr = NULL;
 381 }
 382
 383 /*
 384  * Add channel to trace session
 385  */
 386 int cmd_enable_channels(int argc, const char **argv)
 387 {
 388         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 389         static poptContext pc;
 390         char *session_name = NULL;
 391         char *channel_list = NULL;
 392         char *opt_arg = NULL;
 393         const char *arg_channel_list = NULL;
 394         const char *leftover = NULL;
 395
 396         init_channel_config();
 397
 398         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 399         poptReadDefaultConfig(pc, 0);
 400
 401         while ((opt = poptGetNextOpt(pc)) != -1) {
 402                 switch (opt) {
 403                 case OPT_HELP:
 404                         SHOW_HELP();
 405                         goto end;
 406                 case OPT_DISCARD:
 407                         chan_opts.attr.overwrite = 0;
 408                         DBG("Channel set to discard");
 409                         break;
 410                 case OPT_OVERWRITE:
 411                         chan_opts.attr.overwrite = 1;
 412                         DBG("Channel set to overwrite");
 413                         break;
 414                 case OPT_SUBBUF_SIZE:
 415                 {
 416                         uint64_t rounded_size;
 417                         int order;
 418
 419                         /* Parse the size */
 420                         opt_arg = poptGetOptArg(pc);
 421                         if (utils_parse_size_suffix(opt_arg, &chan_opts.attr.subbuf_size) < 0 || !chan_opts.attr.subbuf_size) {
 422                                 ERR("Wrong value in --subbuf-size parameter: %s", opt_arg);
 423                                 ret = CMD_ERROR;
 424                                 goto end;
 425                         }
 426
 427                         order = get_count_order_u64(chan_opts.attr.subbuf_size);
 428                         assert(order >= 0);
 429                         rounded_size = 1ULL << order;
 430                         if (rounded_size < chan_opts.attr.subbuf_size) {
 431                                 ERR("The subbuf size (%" PRIu64 ") is rounded and overflows!",
 432                                                 chan_opts.attr.subbuf_size);
 433                                 ret = CMD_ERROR;
 434                                 goto end;
 435                         }
 436
 437                         if (rounded_size != chan_opts.attr.subbuf_size) {
 438                                 WARN("The subbuf size (%" PRIu64 ") is rounded to the next power of 2 (%" PRIu64 ")",
 439                                                 chan_opts.attr.subbuf_size, rounded_size);
 440                                 chan_opts.attr.subbuf_size = rounded_size;
 441                         }
 442
 443                         /* Should now be power of 2 */
 444                         assert(!((chan_opts.attr.subbuf_size - 1) & chan_opts.attr.subbuf_size));
 445
 446                         DBG("Channel subbuf size set to %" PRIu64, chan_opts.attr.subbuf_size);
 447                         break;
 448                 }
 449                 case OPT_NUM_SUBBUF:
 450                 {
 451                         uint64_t rounded_size;
 452                         int order;
 453
 454                         errno = 0;
 455                         opt_arg = poptGetOptArg(pc);
 456                         chan_opts.attr.num_subbuf = strtoull(opt_arg, NULL, 0);
 457                         if (errno != 0 || !chan_opts.attr.num_subbuf || !isdigit(opt_arg[0])) {
 458                                 ERR("Wrong value in --num-subbuf parameter: %s", opt_arg);
 459                                 ret = CMD_ERROR;
 460                                 goto end;
 461                         }
 462
 463                         order = get_count_order_u64(chan_opts.attr.num_subbuf);
 464                         assert(order >= 0);
 465                         rounded_size = 1ULL << order;
 466                         if (rounded_size < chan_opts.attr.num_subbuf) {
 467                                 ERR("The number of subbuffers (%" PRIu64 ") is rounded and overflows!",
 468                                                 chan_opts.attr.num_subbuf);
 469                                 ret = CMD_ERROR;
 470                                 goto end;
 471                         }
 472
 473                         if (rounded_size != chan_opts.attr.num_subbuf) {
 474                                 WARN("The number of subbuffers (%" PRIu64 ") is rounded to the next power of 2 (%" PRIu64 ")",
 475                                                 chan_opts.attr.num_subbuf, rounded_size);
 476                                 chan_opts.attr.num_subbuf = rounded_size;
 477                         }
 478
 479                         /* Should now be power of 2 */
 480                         assert(!((chan_opts.attr.num_subbuf - 1) & chan_opts.attr.num_subbuf));
 481
 482                         DBG("Channel subbuf num set to %" PRIu64, chan_opts.attr.num_subbuf);
 483                         break;
 484                 }
 485                 case OPT_SWITCH_TIMER:
 486                 {
 487                         uint64_t v;
 488
 489                         errno = 0;
 490                         opt_arg = poptGetOptArg(pc);
 491
 492                         if (utils_parse_time_suffix(opt_arg, &v) < 0) {
 493                                 ERR("Wrong value for --switch-timer parameter: %s", opt_arg);
 494                                 ret = CMD_ERROR;
 495                                 goto end;
 496                         }
 497
 498                         if (v != (uint32_t) v) {
 499                                 ERR("32-bit overflow in --switch-timer parameter: %s", opt_arg);
 500                                 ret = CMD_ERROR;
 501                                 goto end;
 502                         }
 503                         chan_opts.attr.switch_timer_interval = (uint32_t) v;
 504                         DBG("Channel switch timer interval set to %d %s",
 505                                         chan_opts.attr.switch_timer_interval,
 506                                         USEC_UNIT);
 507                         break;
 508                 }
 509                 case OPT_READ_TIMER:
 510                 {
 511                         uint64_t v;
 512
 513                         errno = 0;
 514                         opt_arg = poptGetOptArg(pc);
 515
 516                         if (utils_parse_time_suffix(opt_arg, &v) < 0) {
 517                                 ERR("Wrong value for --read-timer parameter: %s", opt_arg);
 518                                 ret = CMD_ERROR;
 519                                 goto end;
 520                         }
 521
 522                         if (v != (uint32_t) v) {
 523                                 ERR("32-bit overflow in --read-timer parameter: %s", opt_arg);
 524                                 ret = CMD_ERROR;
 525                                 goto end;
 526                         }
 527                         chan_opts.attr.read_timer_interval = (uint32_t) v;
 528                         DBG("Channel read timer interval set to %d %s",
 529                                         chan_opts.attr.read_timer_interval,
 530                                         USEC_UNIT);
 531                         break;
 532                 }
 533                 case OPT_MONITOR_TIMER:
 534                 {
 535                         uint64_t v;
 536
 537                         errno = 0;
 538                         opt_arg = poptGetOptArg(pc);
 539
 540                         if (utils_parse_time_suffix(opt_arg, &v) < 0) {
 541                                 ERR("Wrong value for --monitor-timer parameter: %s", opt_arg);
 542                                 ret = CMD_ERROR;
 543                                 goto end;
 544                         }
 545                         opt_monitor_timer.interval = (uint64_t) v;
 546                         opt_monitor_timer.set = true;
 547                         DBG("Channel monitor timer interval set to %" PRIu64 " %s",
 548                                         opt_monitor_timer.interval,
 549                                         USEC_UNIT);
 550                         break;
 551                 }
 552                 case OPT_BLOCKING_TIMEOUT:
 553                 {
 554                         uint64_t v;
 555                         long long v_msec;
 556
 557                         errno = 0;
 558                         opt_arg = poptGetOptArg(pc);
 559
 560                         if (strcmp(opt_arg, "inf") == 0) {
 561                                 opt_blocking_timeout.value = (int64_t) -1;
 562                                 opt_blocking_timeout.set = true;
 563                                 DBG("Channel blocking timeout set to infinity");
 564                                 break;
 565                         }
 566
 567                         if (utils_parse_time_suffix(opt_arg, &v) < 0) {
 568                                 ERR("Wrong value for --blocking-timeout parameter: %s", opt_arg);
 569                                 ret = CMD_ERROR;
 570                                 goto end;
 571                         }
 572
 573                         /*
 574                          * While LTTng-UST and LTTng-tools will accept a
 575                          * blocking timeout expressed in µs, the current
 576                          * tracer implementation relies on poll() which
 577                          * takes an "int timeout" parameter expressed in
 578                          * msec.
 579                          *
 580                          * Since the error reporting from the tracer is
 581                          * not precise, we perform this check here to
 582                          * provide a helpful error message in case of
 583                          * overflow.
 584                          *
 585                          * The setter (liblttng-ctl) also performs an
 586                          * equivalent check.
 587                          */
 588                         v_msec = v / 1000;
 589                         if (v_msec != (int32_t) v_msec) {
 590                                 ERR("32-bit milliseconds overflow in --blocking-timeout parameter: %s", opt_arg);
 591                                 ret = CMD_ERROR;
 592                                 goto end;
 593                         }
 594
 595                         opt_blocking_timeout.value = (int64_t) v;
 596                         opt_blocking_timeout.set = true;
 597                         DBG("Channel blocking timeout set to %" PRId64 " %s%s",
 598                                         opt_blocking_timeout.value,
 599                                         USEC_UNIT,
 600                                         opt_blocking_timeout.value == 0 ?
 601                                                 " (non-blocking)" : "");
 602                         break;
 603                 }
 604                 case OPT_USERSPACE:
 605                         opt_userspace = 1;
 606                         break;
 607                 case OPT_TRACEFILE_SIZE:
 608                         opt_arg = poptGetOptArg(pc);
 609                         if (utils_parse_size_suffix(opt_arg, &chan_opts.attr.tracefile_size) < 0) {
 610                                 ERR("Wrong value in --tracefile-size parameter: %s", opt_arg);
 611                                 ret = CMD_ERROR;
 612                                 goto end;
 613                         }
 614                         DBG("Maximum tracefile size set to %" PRIu64,
 615                                         chan_opts.attr.tracefile_size);
 616                         break;
 617                 case OPT_TRACEFILE_COUNT:
 618                 {
 619                         unsigned long v;
 620
 621                         errno = 0;
 622                         opt_arg = poptGetOptArg(pc);
 623                         v = strtoul(opt_arg, NULL, 0);
 624                         if (errno != 0 || !isdigit(opt_arg[0])) {
 625                                 ERR("Wrong value in --tracefile-count parameter: %s", opt_arg);
 626                                 ret = CMD_ERROR;
 627                                 goto end;
 628                         }
 629                         if (v != (uint32_t) v) {
 630                                 ERR("32-bit overflow in --tracefile-count parameter: %s", opt_arg);
 631                                 ret = CMD_ERROR;
 632                                 goto end;
 633                         }
 634                         chan_opts.attr.tracefile_count = (uint32_t) v;
 635                         DBG("Maximum tracefile count set to %" PRIu64,
 636                                         chan_opts.attr.tracefile_count);
 637                         break;
 638                 }
 639                 case OPT_LIST_OPTIONS:
 640                         list_cmd_options(stdout, long_options);
 641                         goto end;
 642                 default:
 643                         ret = CMD_UNDEFINED;
 644                         goto end;
 645                 }
 646
 647                 if (opt_arg) {
 648                         free(opt_arg);
 649                         opt_arg = NULL;
 650                 }
 651         }
 652
 653         ret = print_missing_or_multiple_domains(
 654                         opt_kernel + opt_userspace, false);
 655         if (ret) {
 656                 ret = CMD_ERROR;
 657                 goto end;
 658         }
 659
 660         if (chan_opts.attr.overwrite == 1 && opt_blocking_timeout.set &&
 661                         opt_blocking_timeout.value != 0) {
 662                 ERR("You cannot specify --overwrite and --blocking-timeout=N, "
 663                         "where N is different than 0");
 664                 ret = CMD_ERROR;
 665                 goto end;
 666         }
 667
 668         /* Mi check */
 669         if (lttng_opt_mi) {
 670                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 671                 if (!writer) {
 672                         ret = -LTTNG_ERR_NOMEM;
 673                         goto end;
 674                 }
 675
 676                 /* Open command element */
 677                 ret = mi_lttng_writer_command_open(writer,
 678                                 mi_lttng_element_command_enable_channels);
 679                 if (ret) {
 680                         ret = CMD_ERROR;
 681                         goto end;
 682                 }
 683
 684                 /* Open output element */
 685                 ret = mi_lttng_writer_open_element(writer,
 686                                 mi_lttng_element_command_output);
 687                 if (ret) {
 688                         ret = CMD_ERROR;
 689                         goto end;
 690                 }
 691         }
 692
 693         arg_channel_list = poptGetArg(pc);
 694         if (arg_channel_list == NULL) {
 695                 ERR("Missing channel name.");
 696                 ret = CMD_ERROR;
 697                 success = 0;
 698                 goto mi_closing;
 699         }
 700
 701         channel_list = strdup(arg_channel_list);
 702         if (channel_list == NULL) {
 703                 PERROR("Failed to copy channel name");
 704                 ret = CMD_ERROR;
 705                 success = 0;
 706                 goto mi_closing;
 707         }
 708
 709         leftover = poptGetArg(pc);
 710         if (leftover) {
 711                 ERR("Unknown argument: %s", leftover);
 712                 ret = CMD_ERROR;
 713                 success = 0;
 714                 goto mi_closing;
 715         }
 716
 717         if (!opt_session_name) {
 718                 session_name = get_session_name();
 719                 if (session_name == NULL) {
 720                         command_ret = CMD_ERROR;
 721                         success = 0;
 722                         goto mi_closing;
 723                 }
 724         } else {
 725                 session_name = opt_session_name;
 726         }
 727
 728         command_ret = enable_channel(session_name, channel_list);
 729         if (command_ret) {
 730                 success = 0;
 731         }
 732
 733 mi_closing:
 734         /* Mi closing */
 735         if (lttng_opt_mi) {
 736                 /* Close  output element */
 737                 ret = mi_lttng_writer_close_element(writer);
 738                 if (ret) {
 739                         goto end;
 740                 }
 741
 742                 /* Success ? */
 743                 ret = mi_lttng_writer_write_element_bool(writer,
 744                                 mi_lttng_element_command_success, success);
 745                 if (ret) {
 746                         goto end;
 747                 }
 748
 749                 /* Command element close */
 750                 ret = mi_lttng_writer_command_close(writer);
 751                 if (ret) {
 752                         goto end;
 753                 }
 754         }
 755
 756 end:
 757         /* Mi clean-up */
 758         if (writer && mi_lttng_writer_destroy(writer)) {
 759                 /* Preserve original error code */
 760                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 761         }
 762
 763         if (!opt_session_name && session_name) {
 764                 free(session_name);
 765         }
 766
 767         free(channel_list);
 768
 769         /* Overwrite ret if an error occurred when enable_channel */
 770         ret = command_ret ? command_ret : ret;
 771         poptFreeContext(pc);
 772         free(opt_arg);
 773         return ret;
 774 }