src/bin/lttng/commands/stop.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/sessiond-comm/sessiond-comm.h>
  29 #include <common/mi-lttng.h>
  30
  31 #include "../command.h"
  32
  33 static char *opt_session_name;
  34 static int opt_no_wait;
  35 static struct mi_writer *writer;
  36
  37 enum {
  38         OPT_HELP = 1,
  39         OPT_LIST_OPTIONS,
  40 };
  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         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  46         {"no-wait",   'n', POPT_ARG_VAL, &opt_no_wait, 1, 0, 0},
  47         {0, 0, 0, 0, 0, 0, 0}
  48 };
  49
  50 /*
  51  * usage
  52  */
  53 static void usage(FILE *ofp)
  54 {
  55         fprintf(ofp, "usage: lttng stop [NAME] [OPTIONS]\n");
  56         fprintf(ofp, "\n");
  57         fprintf(ofp, "Where NAME is an optional session name. If not specified, lttng will\n");
  58         fprintf(ofp, "get it from the configuration directory (.lttng).\n");
  59         fprintf(ofp, "\n");
  60         fprintf(ofp, "Options:\n");
  61         fprintf(ofp, "  -h, --help               Show this help\n");
  62         fprintf(ofp, "      --list-options       Simple listing of options\n");
  63         fprintf(ofp, "  -n, --no-wait            Don't wait for data availability\n");
  64         fprintf(ofp, "\n");
  65 }
  66 /*
  67  * Mi print of partial session
  68  */
  69 static int mi_print_session(char *session_name, int enabled)
  70 {
  71         int ret;
  72         assert(writer);
  73         assert(session_name);
  74
  75         /* Open session element */
  76         ret = mi_lttng_writer_open_element(writer, config_element_session);
  77         if (ret) {
  78                 goto end;
  79         }
  80
  81         /* Print session name element */
  82         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  83                         session_name);
  84         if (ret) {
  85                 goto end;
  86         }
  87
  88         /* Is enabled ? */
  89         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
  90                         enabled);
  91         if (ret) {
  92                 goto end;
  93         }
  94
  95         /* Close session element */
  96         ret = mi_lttng_writer_close_element(writer);
  97
  98 end:
  99         return ret;
 100 }
 101
 102 /*
 103  * Start tracing for all trace of the session.
 104  */
 105 static int stop_tracing(void)
 106 {
 107         int ret;
 108         char *session_name;
 109
 110         if (opt_session_name == NULL) {
 111                 session_name = get_session_name();
 112                 if (session_name == NULL) {
 113                         ret = CMD_ERROR;
 114                         goto error;
 115                 }
 116         } else {
 117                 session_name = opt_session_name;
 118         }
 119
 120         ret = lttng_stop_tracing_no_wait(session_name);
 121         if (ret < 0) {
 122                 switch (-ret) {
 123                 case LTTNG_ERR_TRACE_ALREADY_STOPPED:
 124                         WARN("Tracing already stopped for session %s", session_name);
 125                         break;
 126                 default:
 127                         ERR("%s", lttng_strerror(ret));
 128                         break;
 129                 }
 130                 goto free_name;
 131         }
 132
 133         if (!opt_no_wait) {
 134                 _MSG("Waiting for data availability");
 135                 fflush(stdout);
 136                 do {
 137                         ret = lttng_data_pending(session_name);
 138                         if (ret < 0) {
 139                                 /* Return the data available call error. */
 140                                 goto free_name;
 141                         }
 142
 143                         /*
 144                          * Data sleep time before retrying (in usec). Don't sleep if the call
 145                          * returned value indicates availability.
 146                          */
 147                         if (ret) {
 148                                 usleep(DEFAULT_DATA_AVAILABILITY_WAIT_TIME);
 149                                 _MSG(".");
 150                                 fflush(stdout);
 151                         }
 152                 } while (ret != 0);
 153                 MSG("");
 154         }
 155
 156         ret = CMD_SUCCESS;
 157
 158         MSG("Tracing stopped for session %s", session_name);
 159         if (lttng_opt_mi) {
 160                 ret = mi_print_session(session_name, 0);
 161                 if (ret) {
 162                         goto free_name;
 163                 }
 164         }
 165
 166 free_name:
 167         if (opt_session_name == NULL) {
 168                 free(session_name);
 169         }
 170
 171 error:
 172         return ret;
 173 }
 174
 175 /*
 176  *  cmd_stop
 177  *
 178  *  The 'stop <options>' first level command
 179  */
 180 int cmd_stop(int argc, const char **argv)
 181 {
 182         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 183         static poptContext pc;
 184
 185         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 186         poptReadDefaultConfig(pc, 0);
 187
 188         while ((opt = poptGetNextOpt(pc)) != -1) {
 189                 switch (opt) {
 190                 case OPT_HELP:
 191                         usage(stdout);
 192                         goto end;
 193                 case OPT_LIST_OPTIONS:
 194                         list_cmd_options(stdout, long_options);
 195                         goto end;
 196                 default:
 197                         usage(stderr);
 198                         ret = CMD_UNDEFINED;
 199                         goto end;
 200                 }
 201         }
 202
 203         /* Mi check */
 204         if (lttng_opt_mi) {
 205                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 206                 if (!writer) {
 207                         ret = -LTTNG_ERR_NOMEM;
 208                         goto end;
 209                 }
 210
 211                 /* Open command element */
 212                 ret = mi_lttng_writer_command_open(writer,
 213                                 mi_lttng_element_command_stop);
 214                 if (ret) {
 215                         ret = CMD_ERROR;
 216                         goto end;
 217                 }
 218
 219                 /* Open output element */
 220                 ret = mi_lttng_writer_open_element(writer,
 221                                 mi_lttng_element_command_output);
 222                 if (ret) {
 223                         ret = CMD_ERROR;
 224                         goto end;
 225                 }
 226
 227                 /*
 228                  * Open sessions element
 229                  * For validation
 230                  */
 231                 ret = mi_lttng_writer_open_element(writer,
 232                                 config_element_sessions);
 233                 if (ret) {
 234                         ret = CMD_ERROR;
 235                         goto end;
 236                 }
 237         }
 238
 239         opt_session_name = (char*) poptGetArg(pc);
 240
 241         command_ret = stop_tracing();
 242         if (command_ret) {
 243                 success = 0;
 244         }
 245
 246         /* Mi closing */
 247         if (lttng_opt_mi) {
 248                 /* Close sessions and  output element */
 249                 ret = mi_lttng_close_multi_element(writer, 2);
 250                 if (ret) {
 251                         ret = CMD_ERROR;
 252                         goto end;
 253                 }
 254
 255                 /* Success ? */
 256                 ret = mi_lttng_writer_write_element_bool(writer,
 257                                 mi_lttng_element_command_success, success);
 258                 if (ret) {
 259                         ret = CMD_ERROR;
 260                         goto end;
 261                 }
 262
 263                 /* Command element close */
 264                 ret = mi_lttng_writer_command_close(writer);
 265                 if (ret) {
 266                         ret = CMD_ERROR;
 267                         goto end;
 268                 }
 269         }
 270
 271 end:
 272         /* Mi clean-up */
 273         if (writer && mi_lttng_writer_destroy(writer)) {
 274                 /* Preserve original error code */
 275                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 276         }
 277
 278         /* Overwrite ret if an error occurred in stop_tracing() */
 279         ret = command_ret ? command_ret : ret;
 280
 281         poptFreeContext(pc);
 282         return ret;
 283 }