src/bin/lttng/commands/disable_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 <assert.h>
  17
  18 #include <common/mi-lttng.h>
  19
  20 #include "../command.h"
  21
  22 static char *opt_channels;
  23 static int opt_kernel;
  24 static char *opt_session_name;
  25 static int opt_userspace;
  26
  27 #ifdef LTTNG_EMBED_HELP
  28 static const char help_msg[] =
  29 #include <lttng-disable-channel.1.h>
  30 ;
  31 #endif
  32
  33 enum {
  34         OPT_HELP = 1,
  35         OPT_USERSPACE,
  36         OPT_LIST_OPTIONS,
  37 };
  38
  39 static struct lttng_handle *handle;
  40 static struct mi_writer *writer;
  41
  42 static struct poptOption long_options[] = {
  43         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  44         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  45         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  46         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  47         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  48         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  49         {0, 0, 0, 0, 0, 0, 0}
  50 };
  51
  52 static int mi_partial_channel_print(char *channel_name, unsigned int enabled,
  53                 int success)
  54 {
  55         int ret;
  56
  57         assert(writer);
  58         assert(channel_name);
  59
  60         /* Open channel element */
  61         ret = mi_lttng_writer_open_element(writer, config_element_channel);
  62         if (ret) {
  63                 goto end;
  64         }
  65
  66         /* Name */
  67         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  68                         channel_name);
  69         if (ret) {
  70                 goto end;
  71         }
  72
  73         /* Enabled ? */
  74         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
  75                         enabled);
  76         if (ret) {
  77                 goto end;
  78         }
  79
  80         /* Success ? */
  81         ret = mi_lttng_writer_write_element_bool(writer,
  82                         mi_lttng_element_success, success);
  83         if (ret) {
  84                 goto end;
  85         }
  86
  87         /* Closing channel element */
  88         ret = mi_lttng_writer_close_element(writer);
  89
  90 end:
  91         return ret;
  92 }
  93
  94 /*
  95  * Disabling channel using the lttng API.
  96  */
  97 static int disable_channels(char *session_name)
  98 {
  99         int ret = CMD_SUCCESS, warn = 0, success;
 100
 101         /* Normal case for disable channed is enabled = 0 */
 102         unsigned int enabled = 0;
 103         char *channel_name;
 104         struct lttng_domain dom;
 105
 106         memset(&dom, 0, sizeof(dom));
 107
 108         /* Create lttng domain */
 109         if (opt_kernel) {
 110                 dom.type = LTTNG_DOMAIN_KERNEL;
 111         } else if (opt_userspace) {
 112                 dom.type = LTTNG_DOMAIN_UST;
 113         } else {
 114                 /* Checked by the caller. */
 115                 assert(0);
 116         }
 117
 118         handle = lttng_create_handle(session_name, &dom);
 119         if (handle == NULL) {
 120                 ret = -1;
 121                 goto error;
 122         }
 123
 124         /* Prepare MI */
 125         if (lttng_opt_mi) {
 126                 /* open a channels element */
 127                 ret = mi_lttng_writer_open_element(writer, config_element_channels);
 128                 if (ret) {
 129                         ret = CMD_ERROR;
 130                         goto error;
 131                 }
 132
 133         }
 134
 135         /* Strip channel list */
 136         channel_name = strtok(opt_channels, ",");
 137         while (channel_name != NULL) {
 138                 DBG("Disabling channel %s", channel_name);
 139
 140                 ret = lttng_disable_channel(handle, channel_name);
 141                 if (ret < 0) {
 142                         ERR("Channel %s: %s (session %s)", channel_name,
 143                                         lttng_strerror(ret), session_name);
 144                         warn = 1;
 145
 146                         /*
 147                          * Mi:
 148                          * We assume that if an error occurred the channel is still active.
 149                          * This might not be the case but is a good assumption.
 150                          * The client should look at the stderr stream
 151                          * for more informations.
 152                          */
 153                         enabled = 1;
 154                         success = 0;
 155
 156                 } else {
 157                         MSG("%s channel %s disabled for session %s",
 158                                         get_domain_str(dom.type), channel_name, session_name);
 159                         enabled = 0;
 160                         success = 1;
 161                 }
 162
 163                 /* Print the channel */
 164                 if (lttng_opt_mi) {
 165                         ret = mi_partial_channel_print(channel_name, enabled, success);
 166                         if (ret) {
 167                                 ret = CMD_ERROR;
 168                                 goto error;
 169                         }
 170                 }
 171
 172                 /* Next channel */
 173                 channel_name = strtok(NULL, ",");
 174         }
 175
 176         ret = CMD_SUCCESS;
 177
 178         /* Close Mi */
 179         if (lttng_opt_mi) {
 180                 /* Close channels element */
 181                 ret = mi_lttng_writer_close_element(writer);
 182                 if (ret) {
 183                         ret = CMD_ERROR;
 184                         goto error;
 185                 }
 186         }
 187
 188 error:
 189         /* Bypass the warning if a more important error happened */
 190         if (!ret && warn) {
 191                 ret = CMD_WARNING;
 192         }
 193
 194         lttng_destroy_handle(handle);
 195
 196         return ret;
 197 }
 198
 199 /*
 200  *  cmd_disable_channels
 201  *
 202  *  Disable channel to trace session
 203  */
 204 int cmd_disable_channels(int argc, const char **argv)
 205 {
 206         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 207         static poptContext pc;
 208         char *session_name = NULL;
 209         const char *leftover = NULL;
 210
 211         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 212         poptReadDefaultConfig(pc, 0);
 213
 214         while ((opt = poptGetNextOpt(pc)) != -1) {
 215                 switch (opt) {
 216                 case OPT_HELP:
 217                         SHOW_HELP();
 218                         goto end;
 219                 case OPT_USERSPACE:
 220                         opt_userspace = 1;
 221                         break;
 222                 case OPT_LIST_OPTIONS:
 223                         list_cmd_options(stdout, long_options);
 224                         goto end;
 225                 default:
 226                         ret = CMD_UNDEFINED;
 227                         goto end;
 228                 }
 229         }
 230
 231         ret = print_missing_or_multiple_domains(
 232                         opt_kernel + opt_userspace, false);
 233         if (ret) {
 234                 ret = CMD_ERROR;
 235                 goto end;
 236         }
 237
 238         opt_channels = (char*) poptGetArg(pc);
 239         if (opt_channels == NULL) {
 240                 ERR("Missing channel name(s).\n");
 241                 ret = CMD_ERROR;
 242                 goto end;
 243         }
 244
 245         leftover = poptGetArg(pc);
 246         if (leftover) {
 247                 ERR("Unknown argument: %s", leftover);
 248                 ret = CMD_ERROR;
 249                 goto end;
 250         }
 251
 252         if (!opt_session_name) {
 253                 session_name = get_session_name();
 254                 if (session_name == NULL) {
 255                         ret = CMD_ERROR;
 256                         goto end;
 257                 }
 258         } else {
 259                 session_name = opt_session_name;
 260         }
 261
 262         /* Mi check */
 263         if (lttng_opt_mi) {
 264                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 265                 if (!writer) {
 266                         ret = -LTTNG_ERR_NOMEM;
 267                         goto end;
 268                 }
 269
 270                 /* Open command element */
 271                 ret = mi_lttng_writer_command_open(writer,
 272                                 mi_lttng_element_command_disable_channel);
 273                 if (ret) {
 274                         ret = CMD_ERROR;
 275                         goto end;
 276                 }
 277
 278                 /* Open output element */
 279                 ret = mi_lttng_writer_open_element(writer,
 280                                 mi_lttng_element_command_output);
 281                 if (ret) {
 282                         ret = CMD_ERROR;
 283                         goto end;
 284                 }
 285         }
 286
 287         command_ret = disable_channels(session_name);
 288         if (command_ret) {
 289                 success = 0;
 290         }
 291
 292         /* Mi closing */
 293         if (lttng_opt_mi) {
 294                 /* Close  output element */
 295                 ret = mi_lttng_writer_close_element(writer);
 296                 if (ret) {
 297                         ret = CMD_ERROR;
 298                         goto end;
 299                 }
 300
 301                 /* Success ? */
 302                 ret = mi_lttng_writer_write_element_bool(writer,
 303                                 mi_lttng_element_success, success);
 304                 if (ret) {
 305                         ret = CMD_ERROR;
 306                         goto end;
 307                 }
 308
 309                 /* Command element close */
 310                 ret = mi_lttng_writer_command_close(writer);
 311                 if (ret) {
 312                         ret = CMD_ERROR;
 313                         goto end;
 314                 }
 315         }
 316
 317 end:
 318         /* Mi clean-up */
 319         if (writer && mi_lttng_writer_destroy(writer)) {
 320                 /* Preserve original error code */
 321                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 322         }
 323
 324         if (!opt_session_name && session_name) {
 325                 free(session_name);
 326         }
 327
 328         /* Overwrite ret if an error occurred in disable_channels */
 329         ret = command_ret ? command_ret : ret;
 330
 331         poptFreeContext(pc);
 332         return ret;
 333 }