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