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 #if 0
  38 /* Not implemented yet */
  39 static char *opt_cmd_name;
  40 static pid_t opt_pid;
  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 #if 0
  58         /* Not implemented yet */
  59         {"userspace",      'u', POPT_ARG_STRING | POPT_ARGFLAG_OPTIONAL, &opt_cmd_name, OPT_USERSPACE, 0, 0},
  60         {"pid",            'p', POPT_ARG_INT, &opt_pid, 0, 0, 0},
  61 #else
  62         {"userspace",      'u', POPT_ARG_NONE, 0, OPT_USERSPACE, 0, 0},
  63 #endif
  64         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  65         {0, 0, 0, 0, 0, 0, 0}
  66 };
  67
  68 /*
  69  * usage
  70  */
  71 static void usage(FILE *ofp)
  72 {
  73         fprintf(ofp, "usage: lttng disable-channel NAME[,NAME2,...] (-k | -u) [OPTIONS]\n");
  74         fprintf(ofp, "\n");
  75         fprintf(ofp, "Options:\n");
  76         fprintf(ofp, "  -h, --help               Show this help\n");
  77         fprintf(ofp, "      --list-options       Simple listing of options\n");
  78         fprintf(ofp, "  -s, --session NAME       Apply to session name\n");
  79         fprintf(ofp, "  -k, --kernel             Apply to the kernel tracer\n");
  80         fprintf(ofp, "  -u, --userspace          Apply to the user-space tracer\n");
  81         fprintf(ofp, "\n");
  82 }
  83
  84 static int mi_partial_channel_print(char *channel_name, unsigned int enabled,
  85                 int success)
  86 {
  87         int ret;
  88
  89         assert(writer);
  90         assert(channel_name);
  91
  92         /* Open channel element */
  93         ret = mi_lttng_writer_open_element(writer, config_element_channel);
  94         if (ret) {
  95                 goto end;
  96         }
  97
  98         /* Name */
  99         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
 100                         channel_name);
 101         if (ret) {
 102                 goto end;
 103         }
 104
 105         /* Enabled ? */
 106         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
 107                         enabled);
 108         if (ret) {
 109                 goto end;
 110         }
 111
 112         /* Success ? */
 113         ret = mi_lttng_writer_write_element_bool(writer,
 114                         mi_lttng_element_success, success);
 115         if (ret) {
 116                 goto end;
 117         }
 118
 119         /* Closing channel element */
 120         ret = mi_lttng_writer_close_element(writer);
 121
 122 end:
 123         return ret;
 124 }
 125
 126 /*
 127  * Disabling channel using the lttng API.
 128  */
 129 static int disable_channels(char *session_name)
 130 {
 131         int ret = CMD_SUCCESS, warn = 0, success;
 132
 133         /* Normal case for disable channed is enabled = 0 */
 134         unsigned int enabled = 0;
 135         char *channel_name;
 136         struct lttng_domain dom;
 137
 138         memset(&dom, 0, sizeof(dom));
 139
 140         /* Create lttng domain */
 141         if (opt_kernel) {
 142                 dom.type = LTTNG_DOMAIN_KERNEL;
 143         } else if (opt_userspace) {
 144                 dom.type = LTTNG_DOMAIN_UST;
 145         } else {
 146                 print_missing_domain();
 147                 ret = CMD_ERROR;
 148                 goto error;
 149         }
 150
 151         handle = lttng_create_handle(session_name, &dom);
 152         if (handle == NULL) {
 153                 ret = -1;
 154                 goto error;
 155         }
 156
 157         /* Prepare MI */
 158         if (lttng_opt_mi) {
 159                 /* open a channels element */
 160                 ret = mi_lttng_writer_open_element(writer, config_element_channels);
 161                 if (ret) {
 162                         ret = CMD_ERROR;
 163                         goto error;
 164                 }
 165
 166         }
 167
 168         /* Strip channel list */
 169         channel_name = strtok(opt_channels, ",");
 170         while (channel_name != NULL) {
 171                 DBG("Disabling channel %s", channel_name);
 172
 173                 ret = lttng_disable_channel(handle, channel_name);
 174                 if (ret < 0) {
 175                         ERR("Channel %s: %s (session %s)", channel_name,
 176                                         lttng_strerror(ret), session_name);
 177                         warn = 1;
 178
 179                         /*
 180                          * Mi:
 181                          * We assume that if an error occurred the channel is still active.
 182                          * This might not be the case but is a good assumption.
 183                          * The client should look at the stderr stream
 184                          * for more informations.
 185                          */
 186                         enabled = 1;
 187                         success = 0;
 188
 189                 } else {
 190                         MSG("%s channel %s disabled for session %s",
 191                                         get_domain_str(dom.type), channel_name, session_name);
 192                         enabled = 0;
 193                         success = 1;
 194                 }
 195
 196                 /* Print the channel */
 197                 if (lttng_opt_mi) {
 198                         ret = mi_partial_channel_print(channel_name, enabled, success);
 199                         if (ret) {
 200                                 ret = CMD_ERROR;
 201                                 goto error;
 202                         }
 203                 }
 204
 205                 /* Next channel */
 206                 channel_name = strtok(NULL, ",");
 207         }
 208
 209         ret = CMD_SUCCESS;
 210
 211         /* Close Mi */
 212         if (lttng_opt_mi) {
 213                 /* Close channels element */
 214                 ret = mi_lttng_writer_close_element(writer);
 215                 if (ret) {
 216                         ret = CMD_ERROR;
 217                         goto error;
 218                 }
 219         }
 220
 221 error:
 222         /* Bypass the warning if a more important error happened */
 223         if (!ret && warn) {
 224                 ret = CMD_WARNING;
 225         }
 226
 227         lttng_destroy_handle(handle);
 228
 229         return ret;
 230 }
 231
 232 /*
 233  *  cmd_disable_channels
 234  *
 235  *  Disable channel to trace session
 236  */
 237 int cmd_disable_channels(int argc, const char **argv)
 238 {
 239         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 240         static poptContext pc;
 241         char *session_name = NULL;
 242
 243         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 244         poptReadDefaultConfig(pc, 0);
 245
 246         while ((opt = poptGetNextOpt(pc)) != -1) {
 247                 switch (opt) {
 248                 case OPT_HELP:
 249                         usage(stdout);
 250                         goto end;
 251                 case OPT_USERSPACE:
 252                         opt_userspace = 1;
 253                         break;
 254                 case OPT_LIST_OPTIONS:
 255                         list_cmd_options(stdout, long_options);
 256                         goto end;
 257                 default:
 258                         usage(stderr);
 259                         ret = CMD_UNDEFINED;
 260                         goto end;
 261                 }
 262         }
 263
 264         opt_channels = (char*) poptGetArg(pc);
 265         if (opt_channels == NULL) {
 266                 ERR("Missing channel name(s).\n");
 267                 usage(stderr);
 268                 ret = CMD_ERROR;
 269                 goto end;
 270         }
 271
 272         if (!opt_session_name) {
 273                 session_name = get_session_name();
 274                 if (session_name == NULL) {
 275                         ret = CMD_ERROR;
 276                         goto end;
 277                 }
 278         } else {
 279                 session_name = opt_session_name;
 280         }
 281
 282         /* Mi check */
 283         if (lttng_opt_mi) {
 284                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 285                 if (!writer) {
 286                         ret = -LTTNG_ERR_NOMEM;
 287                         goto end;
 288                 }
 289
 290                 /* Open command element */
 291                 ret = mi_lttng_writer_command_open(writer,
 292                                 mi_lttng_element_command_disable_channel);
 293                 if (ret) {
 294                         ret = CMD_ERROR;
 295                         goto end;
 296                 }
 297
 298                 /* Open output element */
 299                 ret = mi_lttng_writer_open_element(writer,
 300                                 mi_lttng_element_command_output);
 301                 if (ret) {
 302                         ret = CMD_ERROR;
 303                         goto end;
 304                 }
 305         }
 306
 307         command_ret = disable_channels(session_name);
 308         if (command_ret) {
 309                 success = 0;
 310         }
 311
 312         /* Mi closing */
 313         if (lttng_opt_mi) {
 314                 /* Close  output element */
 315                 ret = mi_lttng_writer_close_element(writer);
 316                 if (ret) {
 317                         ret = CMD_ERROR;
 318                         goto end;
 319                 }
 320
 321                 /* Success ? */
 322                 ret = mi_lttng_writer_write_element_bool(writer,
 323                                 mi_lttng_element_success, success);
 324                 if (ret) {
 325                         ret = CMD_ERROR;
 326                         goto end;
 327                 }
 328
 329                 /* Command element close */
 330                 ret = mi_lttng_writer_command_close(writer);
 331                 if (ret) {
 332                         ret = CMD_ERROR;
 333                         goto end;
 334                 }
 335         }
 336
 337 end:
 338         /* Mi clean-up */
 339         if (writer && mi_lttng_writer_destroy(writer)) {
 340                 /* Preserve original error code */
 341                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 342         }
 343
 344         if (!opt_session_name && session_name) {
 345                 free(session_name);
 346         }
 347
 348         /* Overwrite ret if an error occurred in disable_channels */
 349         ret = command_ret ? command_ret : ret;
 350
 351         poptFreeContext(pc);
 352         return ret;
 353 }