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 #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 #if 0
  37 /* Not implemented yet */
  38 static char *opt_cmd_name;
  39 static pid_t opt_pid;
  40 #endif
  41
  42 enum {
  43         OPT_HELP = 1,
  44         OPT_USERSPACE,
  45         OPT_LIST_OPTIONS,
  46 };
  47
  48 static struct lttng_handle *handle;
  49 static struct mi_writer *writer;
  50
  51 static struct poptOption long_options[] = {
  52         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  53         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  54         {"session",        's', POPT_ARG_STRING, &opt_session_name, 0, 0, 0},
  55         {"kernel",         'k', POPT_ARG_VAL, &opt_kernel, 1, 0, 0},
  56 #if 0
  57         /* Not implemented yet */
  58         {"userspace",      'u', POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_cmd_name, OPT_USERSPACE, 0, 0},
  59         {"pid",            'p', POPT_ARG_INT, &opt_pid, 0, 0, 0},
  60 #else
  61         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  62 #endif
  63         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  64         {0, 0, 0, 0, 0, 0, 0}
  65 };
  66
  67 /*
  68  * usage
  69  */
  70 static void usage(FILE *ofp)
  71 {
  72         fprintf(ofp, "usage: lttng disable-channel NAME[,NAME2,...] (-k | -u) [OPTIONS]\n");
  73         fprintf(ofp, "\n");
  74         fprintf(ofp, "Options:\n");
  75         fprintf(ofp, "  -h, --help               Show this help\n");
  76         fprintf(ofp, "      --list-options       Simple listing of options\n");
  77         fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
  78         fprintf(ofp, "  -k, --kernel             Apply to the kernel tracer\n");
  79         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
  80         fprintf(ofp, "\n");
  81 }
  82
  83 static int mi_partial_channel_print(char *channel_name, unsigned int enabled,
  84                 int success)
  85 {
  86         int ret;
  87
  88         assert(writer);
  89         assert(channel_name);
  90
  91         /* Open channel element */
  92         ret = mi_lttng_writer_open_element(writer, config_element_channel);
  93         if (ret) {
  94                 goto end;
  95         }
  96
  97         /* Name */
  98         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  99                         channel_name);
 100         if (ret) {
 101                 goto end;
 102         }
 103
 104         /* Enabled ? */
 105         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
 106                         enabled);
 107         if (ret) {
 108                 goto end;
 109         }
 110
 111         /* Success ? */
 112         ret = mi_lttng_writer_write_element_bool(writer,
 113                         mi_lttng_element_success, success);
 114         if (ret) {
 115                 goto end;
 116         }
 117
 118         /* Closing channel element */
 119         ret = mi_lttng_writer_close_element(writer);
 120
 121 end:
 122         return ret;
 123 }
 124
 125 /*
 126  * Disabling channel using the lttng API.
 127  */
 128 static int disable_channels(char *session_name)
 129 {
 130         int ret = CMD_SUCCESS, warn = 0, success;
 131
 132         /* Normal case for disable channed is enabled = 0 */
 133         unsigned int enabled = 0;
 134         char *channel_name;
 135         struct lttng_domain dom;
 136
 137         memset(&dom, 0, sizeof(dom));
 138
 139         /* Create lttng domain */
 140         if (opt_kernel) {
 141                 dom.type = LTTNG_DOMAIN_KERNEL;
 142         } else if (opt_userspace) {
 143                 dom.type = LTTNG_DOMAIN_UST;
 144         } else {
 145                 print_missing_domain();
 146                 ret = CMD_ERROR;
 147                 goto error;
 148         }
 149
 150         handle = lttng_create_handle(session_name, &dom);
 151         if (handle == NULL) {
 152                 ret = -1;
 153                 goto error;
 154         }
 155
 156         /* Prepare MI */
 157         if (lttng_opt_mi) {
 158                 /* open a channels element */
 159                 ret = mi_lttng_writer_open_element(writer, config_element_channels);
 160                 if (ret) {
 161                         ret = CMD_ERROR;
 162                         goto error;
 163                 }
 164
 165         }
 166
 167         /* Strip channel list */
 168         channel_name = strtok(opt_channels, ",");
 169         while (channel_name != NULL) {
 170                 DBG("Disabling channel %s", channel_name);
 171
 172                 ret = lttng_disable_channel(handle, channel_name);
 173                 if (ret < 0) {
 174                         ERR("Channel %s: %s (session %s)", channel_name,
 175                                         lttng_strerror(ret), session_name);
 176                         warn = 1;
 177
 178                         /*
 179                          * Mi:
 180                          * We assume that if an error occurred the channel is still active.
 181                          * This might not be the case but is a good assumption.
 182                          * The client should look at the stderr stream
 183                          * for more informations.
 184                          */
 185                         enabled = 1;
 186                         success = 0;
 187
 188                 } else {
 189                         MSG("%s channel %s disabled for session %s",
 190                                         get_domain_str(dom.type), channel_name, session_name);
 191                         enabled = 0;
 192                         success = 1;
 193                 }
 194
 195                 /* Print the channel */
 196                 if (lttng_opt_mi) {
 197                         ret = mi_partial_channel_print(channel_name, enabled, success);
 198                         if (ret) {
 199                                 ret = CMD_ERROR;
 200                                 goto error;
 201                         }
 202                 }
 203
 204                 /* Next channel */
 205                 channel_name = strtok(NULL, ",");
 206         }
 207
 208         ret = CMD_SUCCESS;
 209
 210         /* Close Mi */
 211         if (lttng_opt_mi) {
 212                 /* Close channels element */
 213                 ret = mi_lttng_writer_close_element(writer);
 214                 if (ret) {
 215                         ret = CMD_ERROR;
 216                         goto error;
 217                 }
 218         }
 219
 220 error:
 221         /* Bypass the warning if a more important error happened */
 222         if (!ret && warn) {
 223                 ret = CMD_WARNING;
 224         }
 225
 226         lttng_destroy_handle(handle);
 227
 228         return ret;
 229 }
 230
 231 /*
 232  *  cmd_disable_channels
 233  *
 234  *  Disable channel to trace session
 235  */
 236 int cmd_disable_channels(int argc, const char **argv)
 237 {
 238         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 239         static poptContext pc;
 240         char *session_name = NULL;
 241
 242         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 243         poptReadDefaultConfig(pc, 0);
 244
 245         while ((opt = poptGetNextOpt(pc)) != -1) {
 246                 switch (opt) {
 247                 case OPT_HELP:
 248                         usage(stdout);
 249                         goto end;
 250                 case OPT_USERSPACE:
 251                         opt_userspace = 1;
 252                         break;
 253                 case OPT_LIST_OPTIONS:
 254                         list_cmd_options(stdout, long_options);
 255                         goto end;
 256                 default:
 257                         usage(stderr);
 258                         ret = CMD_UNDEFINED;
 259                         goto end;
 260                 }
 261         }
 262
 263         opt_channels = (char*) poptGetArg(pc);
 264         if (opt_channels == NULL) {
 265                 ERR("Missing channel name(s).\n");
 266                 usage(stderr);
 267                 ret = CMD_ERROR;
 268                 goto end;
 269         }
 270
 271         if (!opt_session_name) {
 272                 session_name = get_session_name();
 273                 if (session_name == NULL) {
 274                         ret = CMD_ERROR;
 275                         goto end;
 276                 }
 277         } else {
 278                 session_name = opt_session_name;
 279         }
 280
 281         /* Mi check */
 282         if (lttng_opt_mi) {
 283                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 284                 if (!writer) {
 285                         ret = -LTTNG_ERR_NOMEM;
 286                         goto end;
 287                 }
 288
 289                 /* Open command element */
 290                 ret = mi_lttng_writer_command_open(writer,
 291                                 mi_lttng_element_command_disable_channel);
 292                 if (ret) {
 293                         ret = CMD_ERROR;
 294                         goto end;
 295                 }
 296
 297                 /* Open output element */
 298                 ret = mi_lttng_writer_open_element(writer,
 299                                 mi_lttng_element_command_output);
 300                 if (ret) {
 301                         ret = CMD_ERROR;
 302                         goto end;
 303                 }
 304         }
 305
 306         command_ret = disable_channels(session_name);
 307         if (command_ret) {
 308                 success = 0;
 309         }
 310
 311         /* Mi closing */
 312         if (lttng_opt_mi) {
 313                 /* Close  output element */
 314                 ret = mi_lttng_writer_close_element(writer);
 315                 if (ret) {
 316                         ret = CMD_ERROR;
 317                         goto end;
 318                 }
 319
 320                 /* Success ? */
 321                 ret = mi_lttng_writer_write_element_bool(writer,
 322                                 mi_lttng_element_success, success);
 323                 if (ret) {
 324                         ret = CMD_ERROR;
 325                         goto end;
 326                 }
 327
 328                 /* Command element close */
 329                 ret = mi_lttng_writer_command_close(writer);
 330                 if (ret) {
 331                         ret = CMD_ERROR;
 332                         goto end;
 333                 }
 334         }
 335
 336 end:
 337         /* Mi clean-up */
 338         if (writer && mi_lttng_writer_destroy(writer)) {
 339                 /* Preserve original error code */
 340                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 341         }
 342
 343         if (!opt_session_name && session_name) {
 344                 free(session_name);
 345         }
 346
 347         /* Overwrite ret if an error occurred in disable_channels */
 348         ret = command_ret ? command_ret : ret;
 349
 350         poptFreeContext(pc);
 351         return ret;
 352 }