src/bin/lttng/commands/enable_channels.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 <assert.h>
  28 #include <ctype.h>
  29
  30 #include "../command.h"
  31 #include "../utils.h"
  32
  33 #include <src/common/sessiond-comm/sessiond-comm.h>
  34 #include <src/common/utils.h>
  35
  36 static char *opt_channels;
  37 static int opt_kernel;
  38 static char *opt_session_name;
  39 static int opt_userspace;
  40 static struct lttng_channel chan;
  41 static char *opt_output;
  42 static int opt_buffer_uid;
  43 static int opt_buffer_pid;
  44 static int opt_buffer_global;
  45
  46 enum {
  47         OPT_HELP = 1,
  48         OPT_DISCARD,
  49         OPT_OVERWRITE,
  50         OPT_SUBBUF_SIZE,
  51         OPT_NUM_SUBBUF,
  52         OPT_SWITCH_TIMER,
  53         OPT_READ_TIMER,
  54         OPT_USERSPACE,
  55         OPT_LIST_OPTIONS,
  56         OPT_TRACEFILE_SIZE,
  57         OPT_TRACEFILE_COUNT,
  58 };
  59
  60 static struct lttng_handle *handle;
  61
  62 const char *output_mmap = "mmap";
  63 const char *output_splice = "splice";
  64
  65 static struct poptOption long_options[] = {
  66         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  67         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  68         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  69         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  70         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  71         {"discard",        0,   POPT_ARG_NONE, 0, OPT_DISCARD, 0, 0},
  72         {"overwrite",      0,   POPT_ARG_NONE, 0, OPT_OVERWRITE, 0, 0},
  73         {"subbuf-size",    0,   POPT_ARG_STRING, 0, OPT_SUBBUF_SIZE, 0, 0},
  74         {"num-subbuf",     0,   POPT_ARG_INT, 0, OPT_NUM_SUBBUF, 0, 0},
  75         {"switch-timer",   0,   POPT_ARG_INT, 0, OPT_SWITCH_TIMER, 0, 0},
  76         {"read-timer",     0,   POPT_ARG_INT, 0, OPT_READ_TIMER, 0, 0},
  77         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  78         {"output",         0,   POPT_ARG_STRING, &opt_output, 0, 0, 0},
  79         {"buffers-uid",    0,   POPT_ARG_VAL, &opt_buffer_uid, 1, 0, 0},
  80         {"buffers-pid",    0,   POPT_ARG_VAL, &opt_buffer_pid, 1, 0, 0},
  81         {"buffers-global", 0,   POPT_ARG_VAL, &opt_buffer_global, 1, 0, 0},
  82         {"tracefile-size", 'C',   POPT_ARG_INT, 0, OPT_TRACEFILE_SIZE, 0, 0},
  83         {"tracefile-count", 'W',   POPT_ARG_INT, 0, OPT_TRACEFILE_COUNT, 0, 0},
  84         {0, 0, 0, 0, 0, 0, 0}
  85 };
  86
  87 /*
  88  * usage
  89  */
  90 static void usage(FILE *ofp)
  91 {
  92         fprintf(ofp, "usage: lttng enable-channel NAME[,NAME2,...] (-u | -k) [OPTIONS]\n");
  93         fprintf(ofp, "\n");
  94         fprintf(ofp, "Options:\n");
  95         fprintf(ofp, "  -h, --help               Show this help\n");
  96         fprintf(ofp, "      --list-options       Simple listing of options\n");
  97         fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
  98         fprintf(ofp, "  -k, --kernel             Apply to the kernel tracer\n");
  99         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
 100         fprintf(ofp, "\n");
 101         fprintf(ofp, "Channel options:\n");
 102         fprintf(ofp, "      --discard            Discard event when buffers are full%s\n",
 103                 DEFAULT_CHANNEL_OVERWRITE ? "" : " (default)");
 104         fprintf(ofp, "      --overwrite          Flight recorder mode%s\n",
 105                 DEFAULT_CHANNEL_OVERWRITE ? " (default)" : "");
 106         fprintf(ofp, "      --subbuf-size SIZE   Subbuffer size in bytes {+k,+M,+G}\n");
 107         fprintf(ofp, "                               (default UST uid: %zu, UST pid: %zu, kernel: %zu, metadata: %zu)\n",
 108                 default_get_ust_uid_channel_subbuf_size(),
 109                 default_get_ust_pid_channel_subbuf_size(),
 110                 default_get_kernel_channel_subbuf_size(),
 111                 default_get_metadata_subbuf_size());
 112         fprintf(ofp, "                               Rounded up to the next power of 2.\n");
 113         fprintf(ofp, "      --num-subbuf NUM     Number of subbufers\n");
 114         fprintf(ofp, "                               (default UST uid: %u, UST pid: %u, kernel: %u, metadata: %u)\n",
 115                 DEFAULT_UST_UID_CHANNEL_SUBBUF_NUM, DEFAULT_UST_PID_CHANNEL_SUBBUF_NUM,
 116                 DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM, DEFAULT_METADATA_SUBBUF_NUM);
 117         fprintf(ofp, "                               Rounded up to the next power of 2.\n");
 118         fprintf(ofp, "      --switch-timer USEC  Switch timer interval in usec\n");
 119         fprintf(ofp, "                               (default UST uid: %u, UST pid: %u, kernel: %u, metadata: %u)\n",
 120                 DEFAULT_UST_UID_CHANNEL_SWITCH_TIMER, DEFAULT_UST_PID_CHANNEL_SWITCH_TIMER,
 121                 DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER, DEFAULT_METADATA_SWITCH_TIMER);
 122         fprintf(ofp, "      --read-timer USEC    Read timer interval in usec.\n");
 123         fprintf(ofp, "                               (default UST uid: %u, UST pid: %u, kernel: %u, metadata: %u)\n",
 124                 DEFAULT_UST_UID_CHANNEL_READ_TIMER, DEFAULT_UST_UID_CHANNEL_READ_TIMER,
 125                 DEFAULT_KERNEL_CHANNEL_READ_TIMER, DEFAULT_METADATA_READ_TIMER);
 126         fprintf(ofp, "      --output TYPE        Channel output type (Values: %s, %s)\n",
 127                         output_mmap, output_splice);
 128         fprintf(ofp, "                               (default UST uid: %s, UST pid: %s, kernel: %s, metadata: %s)\n",
 129                         DEFAULT_UST_UID_CHANNEL_OUTPUT == LTTNG_EVENT_MMAP ? output_mmap : output_splice,
 130                         DEFAULT_UST_PID_CHANNEL_OUTPUT == LTTNG_EVENT_MMAP ? output_mmap : output_splice,
 131                         DEFAULT_KERNEL_CHANNEL_OUTPUT == LTTNG_EVENT_MMAP ? output_mmap : output_splice,
 132                         DEFAULT_METADATA_OUTPUT == LTTNG_EVENT_MMAP ? output_mmap : output_splice);
 133         fprintf(ofp, "      --buffers-uid        Use per UID buffer (-u only)\n");
 134         fprintf(ofp, "      --buffers-pid        Use per PID buffer (-u only)\n");
 135         fprintf(ofp, "      --buffers-global     Use shared buffer for the whole system (-k only)\n");
 136         fprintf(ofp, "  -C, --tracefile-size SIZE\n");
 137         fprintf(ofp, "                           Maximum size of each tracefile within a stream (in bytes). 0 means unlimited.\n");
 138         fprintf(ofp, "                               (default: %u)\n", DEFAULT_CHANNEL_TRACEFILE_SIZE);
 139         fprintf(ofp, "  -W, --tracefile-count COUNT\n");
 140         fprintf(ofp, "                           Used in conjunction with -C option, this will limit the number\n");
 141         fprintf(ofp, "                           of files created to the specified count. 0 means unlimited.\n");
 142         fprintf(ofp, "                               (default: %u)\n", DEFAULT_CHANNEL_TRACEFILE_COUNT);
 143         fprintf(ofp, "\n");
 144 }
 145
 146 /*
 147  * Set default attributes depending on those already defined from the command
 148  * line.
 149  */
 150 static void set_default_attr(struct lttng_domain *dom)
 151 {
 152         struct lttng_channel_attr default_attr;
 153
 154         /* Set attributes */
 155         lttng_channel_set_default_attr(dom, &default_attr);
 156
 157         if (chan.attr.overwrite == -1) {
 158                 chan.attr.overwrite = default_attr.overwrite;
 159         }
 160         if (chan.attr.subbuf_size == -1) {
 161                 chan.attr.subbuf_size = default_attr.subbuf_size;
 162         }
 163         if (chan.attr.num_subbuf == -1) {
 164                 chan.attr.num_subbuf = default_attr.num_subbuf;
 165         }
 166         if (chan.attr.switch_timer_interval == -1) {
 167                 chan.attr.switch_timer_interval = default_attr.switch_timer_interval;
 168         }
 169         if (chan.attr.read_timer_interval == -1) {
 170                 chan.attr.read_timer_interval = default_attr.read_timer_interval;
 171         }
 172         if ((int) chan.attr.output == -1) {
 173                 chan.attr.output = default_attr.output;
 174         }
 175         if (chan.attr.tracefile_count == -1) {
 176                 chan.attr.tracefile_count = default_attr.tracefile_count;
 177         }
 178         if (chan.attr.tracefile_size == -1) {
 179                 chan.attr.tracefile_size = default_attr.tracefile_size;
 180         }
 181 }
 182
 183 /*
 184  * Adding channel using the lttng API.
 185  */
 186 static int enable_channel(char *session_name)
 187 {
 188         int ret = CMD_SUCCESS, warn = 0;
 189         char *channel_name;
 190         struct lttng_domain dom;
 191
 192         memset(&dom, 0, sizeof(dom));
 193
 194         /* Create lttng domain */
 195         if (opt_kernel) {
 196                 dom.type = LTTNG_DOMAIN_KERNEL;
 197                 dom.buf_type = LTTNG_BUFFER_GLOBAL;
 198                 if (opt_buffer_uid || opt_buffer_pid) {
 199                         ERR("Buffer type not supported for domain -k");
 200                         ret = CMD_ERROR;
 201                         goto error;
 202                 }
 203         } else if (opt_userspace) {
 204                 dom.type = LTTNG_DOMAIN_UST;
 205                 if (opt_buffer_pid) {
 206                         dom.buf_type = LTTNG_BUFFER_PER_PID;
 207                 } else {
 208                         if (opt_buffer_global) {
 209                                 ERR("Buffer type not supported for domain -u");
 210                                 ret = CMD_ERROR;
 211                                 goto error;
 212                         }
 213                         dom.buf_type = LTTNG_BUFFER_PER_UID;
 214                 }
 215         } else {
 216                 print_missing_domain();
 217                 ret = CMD_ERROR;
 218                 goto error;
 219         }
 220
 221         set_default_attr(&dom);
 222
 223         if (chan.attr.tracefile_size == 0 && chan.attr.tracefile_count) {
 224                 ERR("Missing option --tracefile-size. "
 225                                 "A file count without a size won't do anything.");
 226                 ret = CMD_ERROR;
 227                 goto error;
 228         }
 229
 230         if ((chan.attr.tracefile_size > 0) &&
 231                         (chan.attr.tracefile_size < chan.attr.subbuf_size)) {
 232                 WARN("Tracefile size rounded up from (%" PRIu64 ") to subbuffer size (%" PRIu64 ")",
 233                                 chan.attr.tracefile_size, chan.attr.subbuf_size);
 234                 chan.attr.tracefile_size = chan.attr.subbuf_size;
 235         }
 236
 237         /* Setting channel output */
 238         if (opt_output) {
 239                 if (!strncmp(output_mmap, opt_output, strlen(output_mmap))) {
 240                         chan.attr.output = LTTNG_EVENT_MMAP;
 241                 } else if (!strncmp(output_splice, opt_output, strlen(output_splice))) {
 242                         chan.attr.output = LTTNG_EVENT_SPLICE;
 243                 } else {
 244                         ERR("Unknown output type %s. Possible values are: %s, %s\n",
 245                                         opt_output, output_mmap, output_splice);
 246                         usage(stderr);
 247                         ret = CMD_ERROR;
 248                         goto error;
 249                 }
 250         }
 251
 252         handle = lttng_create_handle(session_name, &dom);
 253         if (handle == NULL) {
 254                 ret = -1;
 255                 goto error;
 256         }
 257
 258         /* Strip channel list (format: chan1,chan2,...) */
 259         channel_name = strtok(opt_channels, ",");
 260         while (channel_name != NULL) {
 261                 /* Validate channel name's length */
 262                 if (strlen(channel_name) >= NAME_MAX) {
 263                         ERR("Channel name is too long (max. %zu characters)",
 264                                         sizeof(chan.name) - 1);
 265                         ret = LTTNG_ERR_INVALID_CHANNEL_NAME;
 266                         goto error;
 267                 }
 268
 269                 /* Copy channel name */
 270                 strcpy(chan.name, channel_name);
 271
 272                 DBG("Enabling channel %s", channel_name);
 273
 274                 ret = lttng_enable_channel(handle, &chan);
 275                 if (ret < 0) {
 276                         switch (-ret) {
 277                         case LTTNG_ERR_KERN_CHAN_EXIST:
 278                         case LTTNG_ERR_UST_CHAN_EXIST:
 279                         case LTTNG_ERR_CHAN_EXIST:
 280                                 WARN("Channel %s: %s (session %s)", channel_name,
 281                                                 lttng_strerror(ret), session_name);
 282                                 goto error;
 283                         case LTTNG_ERR_INVALID_CHANNEL_NAME:
 284                                 ERR("Invalid channel name: \"%s\". "
 285                                     "Channel names may not start with '.', and "
 286                                     "may not contain '/'.", channel_name);
 287                                 goto error;
 288                         default:
 289                                 ERR("Channel %s: %s (session %s)", channel_name,
 290                                                 lttng_strerror(ret), session_name);
 291                                 break;
 292                         }
 293                         warn = 1;
 294                 } else {
 295                         MSG("%s channel %s enabled for session %s",
 296                                         get_domain_str(dom.type), channel_name, session_name);
 297                 }
 298
 299                 channel_name = strtok(NULL, ",");
 300         }
 301
 302         ret = CMD_SUCCESS;
 303
 304 error:
 305         if (warn) {
 306                 ret = CMD_WARNING;
 307         }
 308
 309         lttng_destroy_handle(handle);
 310
 311         return ret;
 312 }
 313
 314 /*
 315  * Default value for channel configuration.
 316  */
 317 static void init_channel_config(void)
 318 {
 319         /*
 320          * Put -1 everywhere so we can identify those set by the command line and
 321          * those needed to be set by the default values.
 322          */
 323         memset(&chan.attr, -1, sizeof(chan.attr));
 324 }
 325
 326 /*
 327  * Add channel to trace session
 328  */
 329 int cmd_enable_channels(int argc, const char **argv)
 330 {
 331         int opt, ret = CMD_SUCCESS;
 332         static poptContext pc;
 333         char *session_name = NULL;
 334         char *opt_arg = NULL;
 335
 336         init_channel_config();
 337
 338         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 339         poptReadDefaultConfig(pc, 0);
 340
 341         while ((opt = poptGetNextOpt(pc)) != -1) {
 342                 switch (opt) {
 343                 case OPT_HELP:
 344                         usage(stdout);
 345                         goto end;
 346                 case OPT_DISCARD:
 347                         chan.attr.overwrite = 0;
 348                         DBG("Channel set to discard");
 349                         break;
 350                 case OPT_OVERWRITE:
 351                         chan.attr.overwrite = 1;
 352                         DBG("Channel set to overwrite");
 353                         break;
 354                 case OPT_SUBBUF_SIZE:
 355                 {
 356                         uint64_t rounded_size;
 357                         int order;
 358
 359                         /* Parse the size */
 360                         opt_arg = poptGetOptArg(pc);
 361                         if (utils_parse_size_suffix(opt_arg, &chan.attr.subbuf_size) < 0 || !chan.attr.subbuf_size) {
 362                                 ERR("Wrong value in --subbuf-size parameter: %s", opt_arg);
 363                                 ret = CMD_ERROR;
 364                                 goto end;
 365                         }
 366
 367                         order = get_count_order_u64(chan.attr.subbuf_size);
 368                         assert(order >= 0);
 369                         rounded_size = 1ULL << order;
 370                         if (rounded_size < chan.attr.subbuf_size) {
 371                                 ERR("The subbuf size (%" PRIu64 ") is rounded and overflows!",
 372                                                 chan.attr.subbuf_size);
 373                                 ret = CMD_ERROR;
 374                                 goto end;
 375                         }
 376
 377                         if (rounded_size != chan.attr.subbuf_size) {
 378                                 WARN("The subbuf size (%" PRIu64 ") is rounded to the next power of 2 (%" PRIu64 ")",
 379                                                 chan.attr.subbuf_size, rounded_size);
 380                                 chan.attr.subbuf_size = rounded_size;
 381                         }
 382
 383                         /* Should now be power of 2 */
 384                         assert(!((chan.attr.subbuf_size - 1) & chan.attr.subbuf_size));
 385
 386                         DBG("Channel subbuf size set to %" PRIu64, chan.attr.subbuf_size);
 387                         break;
 388                 }
 389                 case OPT_NUM_SUBBUF:
 390                 {
 391                         uint64_t rounded_size;
 392                         int order;
 393
 394                         errno = 0;
 395                         opt_arg = poptGetOptArg(pc);
 396                         chan.attr.num_subbuf = strtoull(opt_arg, NULL, 0);
 397                         if (errno != 0 || !chan.attr.num_subbuf || !isdigit(opt_arg[0])) {
 398                                 ERR("Wrong value in --num-subbuf parameter: %s", opt_arg);
 399                                 ret = CMD_ERROR;
 400                                 goto end;
 401                         }
 402
 403                         order = get_count_order_u64(chan.attr.num_subbuf);
 404                         assert(order >= 0);
 405                         rounded_size = 1ULL << order;
 406                         if (rounded_size < chan.attr.num_subbuf) {
 407                                 ERR("The number of subbuffers (%" PRIu64 ") is rounded and overflows!",
 408                                                 chan.attr.num_subbuf);
 409                                 ret = CMD_ERROR;
 410                                 goto end;
 411                         }
 412
 413                         if (rounded_size != chan.attr.num_subbuf) {
 414                                 WARN("The number of subbuffers (%" PRIu64 ") is rounded to the next power of 2 (%" PRIu64 ")",
 415                                                 chan.attr.num_subbuf, rounded_size);
 416                                 chan.attr.num_subbuf = rounded_size;
 417                         }
 418
 419                         /* Should now be power of 2 */
 420                         assert(!((chan.attr.num_subbuf - 1) & chan.attr.num_subbuf));
 421
 422                         DBG("Channel subbuf num set to %" PRIu64, chan.attr.num_subbuf);
 423                         break;
 424                 }
 425                 case OPT_SWITCH_TIMER:
 426                 {
 427                         unsigned long v;
 428
 429                         errno = 0;
 430                         opt_arg = poptGetOptArg(pc);
 431                         v = strtoul(opt_arg, NULL, 0);
 432                         if (errno != 0 || !isdigit(opt_arg[0])) {
 433                                 ERR("Wrong value in --switch-timer parameter: %s", opt_arg);
 434                                 ret = CMD_ERROR;
 435                                 goto end;
 436                         }
 437                         if (v != (uint32_t) v) {
 438                                 ERR("32-bit overflow in --switch-timer parameter: %s", opt_arg);
 439                                 ret = CMD_ERROR;
 440                                 goto end;
 441                         }
 442                         chan.attr.switch_timer_interval = (uint32_t) v;
 443                         DBG("Channel switch timer interval set to %d", chan.attr.switch_timer_interval);
 444                         break;
 445                 }
 446                 case OPT_READ_TIMER:
 447                 {
 448                         unsigned long v;
 449
 450                         errno = 0;
 451                         opt_arg = poptGetOptArg(pc);
 452                         v = strtoul(opt_arg, NULL, 0);
 453                         if (errno != 0 || !isdigit(opt_arg[0])) {
 454                                 ERR("Wrong value in --read-timer parameter: %s", opt_arg);
 455                                 ret = CMD_ERROR;
 456                                 goto end;
 457                         }
 458                         if (v != (uint32_t) v) {
 459                                 ERR("32-bit overflow in --read-timer parameter: %s", opt_arg);
 460                                 ret = CMD_ERROR;
 461                                 goto end;
 462                         }
 463                         chan.attr.read_timer_interval = (uint32_t) v;
 464                         DBG("Channel read timer interval set to %d", chan.attr.read_timer_interval);
 465                         break;
 466                 }
 467                 case OPT_USERSPACE:
 468                         opt_userspace = 1;
 469                         break;
 470                 case OPT_TRACEFILE_SIZE:
 471                         opt_arg = poptGetOptArg(pc);
 472                         if (utils_parse_size_suffix(opt_arg, &chan.attr.tracefile_size) < 0) {
 473                                 ERR("Wrong value in --tracefile-size parameter: %s", opt_arg);
 474                                 ret = CMD_ERROR;
 475                                 goto end;
 476                         }
 477                         DBG("Maximum tracefile size set to %" PRIu64,
 478                                         chan.attr.tracefile_size);
 479                         break;
 480                 case OPT_TRACEFILE_COUNT:
 481                 {
 482                         unsigned long v;
 483
 484                         errno = 0;
 485                         opt_arg = poptGetOptArg(pc);
 486                         v = strtoul(opt_arg, NULL, 0);
 487                         if (errno != 0 || !isdigit(opt_arg[0])) {
 488                                 ERR("Wrong value in --tracefile-count parameter: %s", opt_arg);
 489                                 ret = CMD_ERROR;
 490                                 goto end;
 491                         }
 492                         if (v != (uint32_t) v) {
 493                                 ERR("32-bit overflow in --tracefile-count parameter: %s", opt_arg);
 494                                 ret = CMD_ERROR;
 495                                 goto end;
 496                         }
 497                         chan.attr.tracefile_count = (uint32_t) v;
 498                         DBG("Maximum tracefile count set to %" PRIu64,
 499                                         chan.attr.tracefile_count);
 500                         break;
 501                 }
 502                 case OPT_LIST_OPTIONS:
 503                         list_cmd_options(stdout, long_options);
 504                         goto end;
 505                 default:
 506                         usage(stderr);
 507                         ret = CMD_UNDEFINED;
 508                         goto end;
 509                 }
 510         }
 511
 512         opt_channels = (char*) poptGetArg(pc);
 513         if (opt_channels == NULL) {
 514                 ERR("Missing channel name.\n");
 515                 usage(stderr);
 516                 ret = CMD_ERROR;
 517                 goto end;
 518         }
 519
 520         if (!opt_session_name) {
 521                 session_name = get_session_name();
 522                 if (session_name == NULL) {
 523                         ret = CMD_ERROR;
 524                         goto end;
 525                 }
 526         } else {
 527                 session_name = opt_session_name;
 528         }
 529
 530         ret = enable_channel(session_name);
 531
 532 end:
 533         if (!opt_session_name && session_name) {
 534                 free(session_name);
 535         }
 536         poptFreeContext(pc);
 537         return ret;
 538 }