src/bin/lttng/commands/disable_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 #define _LGPL_SOURCE
  20 #include <popt.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/stat.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27 #include <assert.h>
  28
  29 #include <common/mi-lttng.h>
  30
  31 #include "../command.h"
  32
  33 static char *opt_channels;
  34 static int opt_kernel;
  35 static char *opt_session_name;
  36 static int opt_userspace;
  37
  38 enum {
  39         OPT_HELP = 1,
  40         OPT_USERSPACE,
  41         OPT_LIST_OPTIONS,
  42 };
  43
  44 static struct lttng_handle *handle;
  45 static struct mi_writer *writer;
  46
  47 static struct poptOption long_options[] = {
  48         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  49         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  50         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  51         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  52         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  53         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  54         {0, 0, 0, 0, 0, 0, 0}
  55 };
  56
  57 /*
  58  * usage
  59  */
  60 static void usage(FILE *ofp)
  61 {
  62         fprintf(ofp, "usage: lttng disable-channel NAME[,NAME2,...] (-k | -u) [OPTIONS]\n");
  63         fprintf(ofp, "\n");
  64         fprintf(ofp, "Options:\n");
  65         fprintf(ofp, "  -h, --help               Show this help\n");
  66         fprintf(ofp, "      --list-options       Simple listing of options\n");
  67         fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
  68         fprintf(ofp, "  -k, --kernel             Apply to the kernel tracer\n");
  69         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
  70         fprintf(ofp, "\n");
  71 }
  72
  73 static int mi_partial_channel_print(char *channel_name, unsigned int enabled,
  74                 int success)
  75 {
  76         int ret;
  77
  78         assert(writer);
  79         assert(channel_name);
  80
  81         /* Open channel element */
  82         ret = mi_lttng_writer_open_element(writer, config_element_channel);
  83         if (ret) {
  84                 goto end;
  85         }
  86
  87         /* Name */
  88         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  89                         channel_name);
  90         if (ret) {
  91                 goto end;
  92         }
  93
  94         /* Enabled ? */
  95         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
  96                         enabled);
  97         if (ret) {
  98                 goto end;
  99         }
 100
 101         /* Success ? */
 102         ret = mi_lttng_writer_write_element_bool(writer,
 103                         mi_lttng_element_success, success);
 104         if (ret) {
 105                 goto end;
 106         }
 107
 108         /* Closing channel element */
 109         ret = mi_lttng_writer_close_element(writer);
 110
 111 end:
 112         return ret;
 113 }
 114
 115 /*
 116  * Disabling channel using the lttng API.
 117  */
 118 static int disable_channels(char *session_name)
 119 {
 120         int ret = CMD_SUCCESS, warn = 0, success;
 121
 122         /* Normal case for disable channed is enabled = 0 */
 123         unsigned int enabled = 0;
 124         char *channel_name;
 125         struct lttng_domain dom;
 126
 127         memset(&dom, 0, sizeof(dom));
 128
 129         /* Create lttng domain */
 130         if (opt_kernel) {
 131                 dom.type = LTTNG_DOMAIN_KERNEL;
 132         } else if (opt_userspace) {
 133                 dom.type = LTTNG_DOMAIN_UST;
 134         } else {
 135                 /* Checked by the caller. */
 136                 assert(0);
 137         }
 138
 139         handle = lttng_create_handle(session_name, &dom);
 140         if (handle == NULL) {
 141                 ret = -1;
 142                 goto error;
 143         }
 144
 145         /* Prepare MI */
 146         if (lttng_opt_mi) {
 147                 /* open a channels element */
 148                 ret = mi_lttng_writer_open_element(writer, config_element_channels);
 149                 if (ret) {
 150                         ret = CMD_ERROR;
 151                         goto error;
 152                 }
 153
 154         }
 155
 156         /* Strip channel list */
 157         channel_name = strtok(opt_channels, ",");
 158         while (channel_name != NULL) {
 159                 DBG("Disabling channel %s", channel_name);
 160
 161                 ret = lttng_disable_channel(handle, channel_name);
 162                 if (ret < 0) {
 163                         ERR("Channel %s: %s (session %s)", channel_name,
 164                                         lttng_strerror(ret), session_name);
 165                         warn = 1;
 166
 167                         /*
 168                          * Mi:
 169                          * We assume that if an error occurred the channel is still active.
 170                          * This might not be the case but is a good assumption.
 171                          * The client should look at the stderr stream
 172                          * for more informations.
 173                          */
 174                         enabled = 1;
 175                         success = 0;
 176
 177                 } else {
 178                         MSG("%s channel %s disabled for session %s",
 179                                         get_domain_str(dom.type), channel_name, session_name);
 180                         enabled = 0;
 181                         success = 1;
 182                 }
 183
 184                 /* Print the channel */
 185                 if (lttng_opt_mi) {
 186                         ret = mi_partial_channel_print(channel_name, enabled, success);
 187                         if (ret) {
 188                                 ret = CMD_ERROR;
 189                                 goto error;
 190                         }
 191                 }
 192
 193                 /* Next channel */
 194                 channel_name = strtok(NULL, ",");
 195         }
 196
 197         ret = CMD_SUCCESS;
 198
 199         /* Close Mi */
 200         if (lttng_opt_mi) {
 201                 /* Close channels element */
 202                 ret = mi_lttng_writer_close_element(writer);
 203                 if (ret) {
 204                         ret = CMD_ERROR;
 205                         goto error;
 206                 }
 207         }
 208
 209 error:
 210         /* Bypass the warning if a more important error happened */
 211         if (!ret && warn) {
 212                 ret = CMD_WARNING;
 213         }
 214
 215         lttng_destroy_handle(handle);
 216
 217         return ret;
 218 }
 219
 220 /*
 221  *  cmd_disable_channels
 222  *
 223  *  Disable channel to trace session
 224  */
 225 int cmd_disable_channels(int argc, const char **argv)
 226 {
 227         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 228         static poptContext pc;
 229         char *session_name = NULL;
 230
 231         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 232         poptReadDefaultConfig(pc, 0);
 233
 234         while ((opt = poptGetNextOpt(pc)) != -1) {
 235                 switch (opt) {
 236                 case OPT_HELP:
 237                         usage(stdout);
 238                         goto end;
 239                 case OPT_USERSPACE:
 240                         opt_userspace = 1;
 241                         break;
 242                 case OPT_LIST_OPTIONS:
 243                         list_cmd_options(stdout, long_options);
 244                         goto end;
 245                 default:
 246                         usage(stderr);
 247                         ret = CMD_UNDEFINED;
 248                         goto end;
 249                 }
 250         }
 251
 252         ret = print_missing_or_multiple_domains(opt_kernel + opt_userspace);
 253         if (ret) {
 254                 ret = CMD_ERROR;
 255                 goto end;
 256         }
 257
 258         opt_channels = (char*) poptGetArg(pc);
 259         if (opt_channels == NULL) {
 260                 ERR("Missing channel name(s).\n");
 261                 usage(stderr);
 262                 ret = CMD_ERROR;
 263                 goto end;
 264         }
 265
 266         if (!opt_session_name) {
 267                 session_name = get_session_name();
 268                 if (session_name == NULL) {
 269                         ret = CMD_ERROR;
 270                         goto end;
 271                 }
 272         } else {
 273                 session_name = opt_session_name;
 274         }
 275
 276         /* Mi check */
 277         if (lttng_opt_mi) {
 278                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 279                 if (!writer) {
 280                         ret = -LTTNG_ERR_NOMEM;
 281                         goto end;
 282                 }
 283
 284                 /* Open command element */
 285                 ret = mi_lttng_writer_command_open(writer,
 286                                 mi_lttng_element_command_disable_channel);
 287                 if (ret) {
 288                         ret = CMD_ERROR;
 289                         goto end;
 290                 }
 291
 292                 /* Open output element */
 293                 ret = mi_lttng_writer_open_element(writer,
 294                                 mi_lttng_element_command_output);
 295                 if (ret) {
 296                         ret = CMD_ERROR;
 297                         goto end;
 298                 }
 299         }
 300
 301         command_ret = disable_channels(session_name);
 302         if (command_ret) {
 303                 success = 0;
 304         }
 305
 306         /* Mi closing */
 307         if (lttng_opt_mi) {
 308                 /* Close  output element */
 309                 ret = mi_lttng_writer_close_element(writer);
 310                 if (ret) {
 311                         ret = CMD_ERROR;
 312                         goto end;
 313                 }
 314
 315                 /* Success ? */
 316                 ret = mi_lttng_writer_write_element_bool(writer,
 317                                 mi_lttng_element_success, success);
 318                 if (ret) {
 319                         ret = CMD_ERROR;
 320                         goto end;
 321                 }
 322
 323                 /* Command element close */
 324                 ret = mi_lttng_writer_command_close(writer);
 325                 if (ret) {
 326                         ret = CMD_ERROR;
 327                         goto end;
 328                 }
 329         }
 330
 331 end:
 332         /* Mi clean-up */
 333         if (writer && mi_lttng_writer_destroy(writer)) {
 334                 /* Preserve original error code */
 335                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 336         }
 337
 338         if (!opt_session_name && session_name) {
 339                 free(session_name);
 340         }
 341
 342         /* Overwrite ret if an error occurred in disable_channels */
 343         ret = command_ret ? command_ret : ret;
 344
 345         poptFreeContext(pc);
 346         return ret;
 347 }