src/bin/lttng/commands/enable_channels.c

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