src/bin/lttng/commands/start.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
  27 #include <common/sessiond-comm/sessiond-comm.h>
  28 #include <common/mi-lttng.h>
  29
  30 #include "../command.h"
  31
  32
  33 static char *opt_session_name;
  34 static struct mi_writer *writer;
  35
  36 enum {
  37         OPT_HELP = 1,
  38         OPT_LIST_OPTIONS,
  39 };
  40
  41 static struct poptOption long_options[] = {
  42         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  43         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  44         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  45         {0, 0, 0, 0, 0, 0, 0}
  46 };
  47
  48 static int mi_print_session(char *session_name, int enabled)
  49 {
  50         int ret;
  51
  52         /* Open session element */
  53         ret = mi_lttng_writer_open_element(writer, config_element_session);
  54         if (ret) {
  55                 goto end;
  56         }
  57
  58         /* Print session name element */
  59         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  60                         session_name);
  61         if (ret) {
  62                 goto end;
  63         }
  64
  65         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
  66                         enabled);
  67         if (ret) {
  68                 goto end;
  69         }
  70
  71         /* Close session element */
  72         ret = mi_lttng_writer_close_element(writer);
  73
  74 end:
  75         return ret;
  76 }
  77
  78 /*
  79  *  start_tracing
  80  *
  81  *  Start tracing for all trace of the session.
  82  */
  83 static int start_tracing(void)
  84 {
  85         int ret;
  86         char *session_name;
  87
  88         if (opt_session_name == NULL) {
  89                 session_name = get_session_name();
  90                 if (session_name == NULL) {
  91                         ret = CMD_ERROR;
  92                         goto error;
  93                 }
  94         } else {
  95                 session_name = opt_session_name;
  96         }
  97
  98         DBG("Starting tracing for session %s", session_name);
  99
 100         ret = lttng_start_tracing(session_name);
 101         if (ret < 0) {
 102                 switch (-ret) {
 103                 case LTTNG_ERR_TRACE_ALREADY_STARTED:
 104                         WARN("Tracing already started for session %s", session_name);
 105                         break;
 106                 default:
 107                         ERR("%s", lttng_strerror(ret));
 108                         break;
 109                 }
 110                 goto free_name;
 111         }
 112
 113         ret = CMD_SUCCESS;
 114
 115         MSG("Tracing started for session %s", session_name);
 116         if (lttng_opt_mi) {
 117                 ret = mi_print_session(session_name, 1);
 118                 if (ret) {
 119                         ret = CMD_ERROR;
 120                         goto free_name;
 121                 }
 122         }
 123
 124 free_name:
 125         if (opt_session_name == NULL) {
 126                 free(session_name);
 127         }
 128 error:
 129         return ret;
 130 }
 131
 132 /*
 133  *  cmd_start
 134  *
 135  *  The 'start <options>' first level command
 136  */
 137 int cmd_start(int argc, const char **argv)
 138 {
 139         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 140         static poptContext pc;
 141
 142         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 143         poptReadDefaultConfig(pc, 0);
 144
 145         while ((opt = poptGetNextOpt(pc)) != -1) {
 146                 switch (opt) {
 147                 case OPT_HELP:
 148                         SHOW_HELP();
 149                         goto end;
 150                 case OPT_LIST_OPTIONS:
 151                         list_cmd_options(stdout, long_options);
 152                         goto end;
 153                 default:
 154                         ret = CMD_UNDEFINED;
 155                         goto end;
 156                 }
 157         }
 158
 159         opt_session_name = (char*) poptGetArg(pc);
 160
 161         /* Mi check */
 162         if (lttng_opt_mi) {
 163                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 164                 if (!writer) {
 165                         ret = -LTTNG_ERR_NOMEM;
 166                         goto end;
 167                 }
 168
 169                 /* Open command element */
 170                 ret = mi_lttng_writer_command_open(writer,
 171                                 mi_lttng_element_command_start);
 172                 if (ret) {
 173                         ret = CMD_ERROR;
 174                         goto end;
 175                 }
 176
 177                 /* Open output element */
 178                 ret = mi_lttng_writer_open_element(writer,
 179                                 mi_lttng_element_command_output);
 180                 if (ret) {
 181                         ret = CMD_ERROR;
 182                         goto end;
 183                 }
 184
 185                 /*
 186                  * Open sessions element
 187                  * For validation purpose
 188                  */
 189                 ret = mi_lttng_writer_open_element(writer,
 190                         config_element_sessions);
 191                 if (ret) {
 192                         ret = CMD_ERROR;
 193                         goto end;
 194                 }
 195         }
 196
 197         command_ret = start_tracing();
 198         if (command_ret) {
 199                 success = 0;
 200         }
 201
 202         /* Mi closing */
 203         if (lttng_opt_mi) {
 204                 /* Close  sessions and output element */
 205                 ret = mi_lttng_close_multi_element(writer, 2);
 206                 if (ret) {
 207                         ret = CMD_ERROR;
 208                         goto end;
 209                 }
 210
 211                 /* Success ? */
 212                 ret = mi_lttng_writer_write_element_bool(writer,
 213                                 mi_lttng_element_command_success, success);
 214                 if (ret) {
 215                         ret = CMD_ERROR;
 216                         goto end;
 217                 }
 218
 219                 /* Command element close */
 220                 ret = mi_lttng_writer_command_close(writer);
 221                 if (ret) {
 222                         ret = CMD_ERROR;
 223                         goto end;
 224                 }
 225         }
 226
 227 end:
 228         /* Mi clean-up */
 229         if (writer && mi_lttng_writer_destroy(writer)) {
 230                 /* Preserve original error code */
 231                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 232         }
 233
 234         /* Overwrite ret if an error occurred with start_tracing */
 235         ret = command_ret ? command_ret : ret;
 236         poptFreeContext(pc);
 237         return ret;
 238 }