src/bin/lttng/commands/destroy.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 <stdbool.h>
  27
  28 #include "../command.h"
  29
  30 #include <common/mi-lttng.h>
  31 #include <common/sessiond-comm/sessiond-comm.h>
  32 #include <common/utils.h>
  33
  34 static char *opt_session_name;
  35 static int opt_destroy_all;
  36 static int opt_no_wait;
  37
  38 /* Mi writer */
  39 static struct mi_writer *writer;
  40
  41 enum {
  42         OPT_HELP = 1,
  43         OPT_LIST_OPTIONS,
  44 };
  45
  46 static struct poptOption long_options[] = {
  47         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  48         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  49         {"all",       'a', POPT_ARG_VAL, &opt_destroy_all, 1, 0, 0},
  50         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  51         {"no-wait",   'n', POPT_ARG_VAL, &opt_no_wait, 1, 0, 0},
  52         {0, 0, 0, 0, 0, 0, 0}
  53 };
  54
  55 /*
  56  * usage
  57  */
  58 static void usage(FILE *ofp)
  59 {
  60         fprintf(ofp, "usage: lttng destroy [NAME] [OPTIONS]\n");
  61         fprintf(ofp, "\n");
  62         fprintf(ofp, "Where NAME is an optional session name. If not specified, lttng will\n");
  63         fprintf(ofp, "get it from the configuration directory (.lttng).\n");
  64         fprintf(ofp, "\n");
  65         fprintf(ofp, "Options:\n");
  66         fprintf(ofp, "  -h, --help           Show this help\n");
  67         fprintf(ofp, "  -a, --all            Destroy all sessions\n");
  68         fprintf(ofp, "      --list-options   Simple listing of options\n");
  69         fprintf(ofp, "  -n, --no-wait        Don't wait for data availability\n");
  70         fprintf(ofp, "\n");
  71 }
  72
  73 /*
  74  * destroy_session
  75  *
  76  * Unregister the provided session to the session daemon. On success, removes
  77  * the default configuration.
  78  */
  79 static int destroy_session(struct lttng_session *session)
  80 {
  81         int ret;
  82         char *session_name = NULL;
  83         bool session_was_stopped;
  84
  85         ret = lttng_stop_tracing_no_wait(session->name);
  86         if (ret < 0 && ret != -LTTNG_ERR_TRACE_ALREADY_STOPPED) {
  87                 ERR("%s", lttng_strerror(ret));
  88         }
  89         session_was_stopped = ret == -LTTNG_ERR_TRACE_ALREADY_STOPPED;
  90         if (!opt_no_wait) {
  91                 _MSG("Waiting for data availability");
  92                 fflush(stdout);
  93                 do {
  94                         ret = lttng_data_pending(session->name);
  95                         if (ret < 0) {
  96                                 /* Return the data available call error. */
  97                                 goto error;
  98                         }
  99
 100                         /*
 101                          * Data sleep time before retrying (in usec). Don't sleep if the call
 102                          * returned value indicates availability.
 103                          */
 104                         if (ret) {
 105                                 usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME);
 106                                 _MSG(".");
 107                                 fflush(stdout);
 108                         }
 109                 } while (ret != 0);
 110                 MSG("");
 111         }
 112         if (!session_was_stopped) {
 113                 /*
 114                  * Don't print the event and packet loss warnings since the user
 115                  * already saw them when stopping the trace.
 116                  */
 117                 print_session_stats(session->name);
 118         }
 119
 120         ret = lttng_destroy_session_no_wait(session->name);
 121         if (ret < 0) {
 122                 goto error;
 123         }
 124
 125         MSG("Session %s destroyed", session->name);
 126
 127         session_name = get_session_name_quiet();
 128         if (session_name && !strncmp(session->name, session_name, NAME_MAX)) {
 129                 config_destroy_default();
 130         }
 131
 132         if (lttng_opt_mi) {
 133                 ret = mi_lttng_session(writer, session, 0);
 134                 if (ret) {
 135                         ret = CMD_ERROR;
 136                         goto error;
 137                 }
 138         }
 139
 140         ret = CMD_SUCCESS;
 141 error:
 142         free(session_name);
 143         return ret;
 144 }
 145
 146 /*
 147  * destroy_all_sessions
 148  *
 149  * Call destroy_sessions for each registered sessions
 150  */
 151 static int destroy_all_sessions(struct lttng_session *sessions, int count)
 152 {
 153         int i, ret = CMD_SUCCESS;
 154
 155         if (count == 0) {
 156                 MSG("No session found, nothing to do.");
 157         } else if (count < 0) {
 158                 ERR("%s", lttng_strerror(ret));
 159                 goto error;
 160         }
 161
 162         for (i = 0; i < count; i++) {
 163                 ret = destroy_session(&sessions[i]);
 164                 if (ret < 0) {
 165                         goto error;
 166                 }
 167         }
 168 error:
 169         return ret;
 170 }
 171
 172 /*
 173  * The 'destroy <options>' first level command
 174  */
 175 int cmd_destroy(int argc, const char **argv)
 176 {
 177         int opt;
 178         int ret = CMD_SUCCESS , i, command_ret = CMD_SUCCESS, success = 1;
 179         static poptContext pc;
 180         char *session_name = NULL;
 181
 182         struct lttng_session *sessions;
 183         int count;
 184         int found;
 185
 186         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 187         poptReadDefaultConfig(pc, 0);
 188
 189         while ((opt = poptGetNextOpt(pc)) != -1) {
 190                 switch (opt) {
 191                 case OPT_HELP:
 192                         usage(stdout);
 193                         break;
 194                 case OPT_LIST_OPTIONS:
 195                         list_cmd_options(stdout, long_options);
 196                         break;
 197                 default:
 198                         usage(stderr);
 199                         ret = CMD_UNDEFINED;
 200                         break;
 201                 }
 202                 goto end;
 203         }
 204
 205         /* Mi preparation */
 206         if (lttng_opt_mi) {
 207                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 208                 if (!writer) {
 209                         ret = -LTTNG_ERR_NOMEM;
 210                         goto end;
 211                 }
 212
 213                 /* Open command element */
 214                 ret = mi_lttng_writer_command_open(writer,
 215                                 mi_lttng_element_command_destroy);
 216                 if (ret) {
 217                         ret = CMD_ERROR;
 218                         goto end;
 219                 }
 220
 221                 /* Open output element */
 222                 ret = mi_lttng_writer_open_element(writer,
 223                                 mi_lttng_element_command_output);
 224                 if (ret) {
 225                         ret = CMD_ERROR;
 226                         goto end;
 227                 }
 228
 229                 /* For validation and semantic purpose we open a sessions element */
 230                 ret = mi_lttng_sessions_open(writer);
 231                 if (ret) {
 232                         ret = CMD_ERROR;
 233                         goto end;
 234                 }
 235         }
 236
 237         /* Recuperate all sessions for further operation */
 238         count = lttng_list_sessions(&sessions);
 239         if (count < 0) {
 240                 command_ret = count;
 241                 success = 0;
 242                 goto mi_closing;
 243         }
 244
 245         /* Ignore session name in case all sessions are to be destroyed */
 246         if (opt_destroy_all) {
 247                 command_ret = destroy_all_sessions(sessions, count);
 248                 if (command_ret) {
 249                         success = 0;
 250                 }
 251         } else {
 252                 opt_session_name = (char *) poptGetArg(pc);
 253
 254                 if (!opt_session_name) {
 255                         /* No session name specified, lookup default */
 256                         session_name = get_session_name();
 257                         if (session_name == NULL) {
 258                                 command_ret = CMD_ERROR;
 259                                 success = 0;
 260                                 goto mi_closing;
 261                         }
 262                 } else {
 263                         session_name = opt_session_name;
 264                 }
 265
 266                 /* Find the corresponding lttng_session struct */
 267                 found = 0;
 268                 for (i = 0; i < count; i++) {
 269                         if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 270                                 found = 1;
 271                                 command_ret = destroy_session(&sessions[i]);
 272                                 if (command_ret) {
 273                                         success = 0;
 274                                 }
 275
 276                         }
 277                 }
 278
 279                 if (!found) {
 280                         ERR("Session name %s not found", session_name);
 281                         command_ret = LTTNG_ERR_SESS_NOT_FOUND;
 282                         success = 0;
 283                         goto mi_closing;
 284                 }
 285         }
 286
 287 mi_closing:
 288         /* Mi closing */
 289         if (lttng_opt_mi) {
 290                 /* Close sessions and output element element */
 291                 ret = mi_lttng_close_multi_element(writer, 2);
 292                 if (ret) {
 293                         ret = CMD_ERROR;
 294                         goto end;
 295                 }
 296
 297                 /* Success ? */
 298                 ret = mi_lttng_writer_write_element_bool(writer,
 299                                 mi_lttng_element_command_success, success);
 300                 if (ret) {
 301                         ret = CMD_ERROR;
 302                         goto end;
 303                 }
 304
 305                 /* Command element close */
 306                 ret = mi_lttng_writer_command_close(writer);
 307                 if (ret) {
 308                         ret = CMD_ERROR;
 309                         goto end;
 310                 }
 311         }
 312 end:
 313         /* Mi clean-up */
 314         if (writer && mi_lttng_writer_destroy(writer)) {
 315                 /* Preserve original error code */
 316                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 317         }
 318
 319         if (opt_session_name == NULL) {
 320                 free(session_name);
 321         }
 322
 323         /* Overwrite ret if an error occurred during destroy_session/all */
 324         ret = command_ret ? command_ret : ret;
 325
 326         poptFreeContext(pc);
 327         return ret;
 328 }