src/bin/lttng/commands/start.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <popt.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/stat.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16
  17 #include <common/sessiond-comm/sessiond-comm.h>
  18 #include <common/mi-lttng.h>
  19
  20 #include "../command.h"
  21
  22
  23 static char *opt_session_name;
  24 static struct mi_writer *writer;
  25
  26 #ifdef LTTNG_EMBED_HELP
  27 static const char help_msg[] =
  28 #include <lttng-start.1.h>
  29 ;
  30 #endif
  31
  32 enum {
  33         OPT_HELP = 1,
  34         OPT_LIST_OPTIONS,
  35 };
  36
  37 static struct poptOption long_options[] = {
  38         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  39         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  40         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  41         {0, 0, 0, 0, 0, 0, 0}
  42 };
  43
  44 static int mi_print_session(char *session_name, int enabled)
  45 {
  46         int ret;
  47
  48         /* Open session element */
  49         ret = mi_lttng_writer_open_element(writer, config_element_session);
  50         if (ret) {
  51                 goto end;
  52         }
  53
  54         /* Print session name element */
  55         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  56                         session_name);
  57         if (ret) {
  58                 goto end;
  59         }
  60
  61         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
  62                         enabled);
  63         if (ret) {
  64                 goto end;
  65         }
  66
  67         /* Close session element */
  68         ret = mi_lttng_writer_close_element(writer);
  69
  70 end:
  71         return ret;
  72 }
  73
  74 /*
  75  *  start_tracing
  76  *
  77  *  Start tracing for all trace of the session.
  78  */
  79 static int start_tracing(void)
  80 {
  81         int ret;
  82         char *session_name;
  83
  84         if (opt_session_name == NULL) {
  85                 session_name = get_session_name();
  86                 if (session_name == NULL) {
  87                         ret = CMD_ERROR;
  88                         goto error;
  89                 }
  90         } else {
  91                 session_name = opt_session_name;
  92         }
  93
  94         DBG("Starting tracing for session %s", session_name);
  95
  96         ret = lttng_start_tracing(session_name);
  97         if (ret < 0) {
  98                 switch (-ret) {
  99                 case LTTNG_ERR_TRACE_ALREADY_STARTED:
 100                         WARN("Tracing already started for session %s", session_name);
 101                         break;
 102                 default:
 103                         ERR("%s", lttng_strerror(ret));
 104                         break;
 105                 }
 106                 goto free_name;
 107         }
 108
 109         ret = CMD_SUCCESS;
 110
 111         MSG("Tracing started for session %s", session_name);
 112         if (lttng_opt_mi) {
 113                 ret = mi_print_session(session_name, 1);
 114                 if (ret) {
 115                         ret = CMD_ERROR;
 116                         goto free_name;
 117                 }
 118         }
 119
 120 free_name:
 121         if (opt_session_name == NULL) {
 122                 free(session_name);
 123         }
 124 error:
 125         return ret;
 126 }
 127
 128 /*
 129  *  cmd_start
 130  *
 131  *  The 'start <options>' first level command
 132  */
 133 int cmd_start(int argc, const char **argv)
 134 {
 135         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 136         static poptContext pc;
 137         const char *leftover = NULL;
 138
 139         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 140         poptReadDefaultConfig(pc, 0);
 141
 142         while ((opt = poptGetNextOpt(pc)) != -1) {
 143                 switch (opt) {
 144                 case OPT_HELP:
 145                         SHOW_HELP();
 146                         goto end;
 147                 case OPT_LIST_OPTIONS:
 148                         list_cmd_options(stdout, long_options);
 149                         goto end;
 150                 default:
 151                         ret = CMD_UNDEFINED;
 152                         goto end;
 153                 }
 154         }
 155
 156         opt_session_name = (char*) poptGetArg(pc);
 157
 158         leftover = poptGetArg(pc);
 159         if (leftover) {
 160                 ERR("Unknown argument: %s", leftover);
 161                 ret = CMD_ERROR;
 162                 goto end;
 163         }
 164
 165         /* Mi check */
 166         if (lttng_opt_mi) {
 167                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 168                 if (!writer) {
 169                         ret = -LTTNG_ERR_NOMEM;
 170                         goto end;
 171                 }
 172
 173                 /* Open command element */
 174                 ret = mi_lttng_writer_command_open(writer,
 175                                 mi_lttng_element_command_start);
 176                 if (ret) {
 177                         ret = CMD_ERROR;
 178                         goto end;
 179                 }
 180
 181                 /* Open output element */
 182                 ret = mi_lttng_writer_open_element(writer,
 183                                 mi_lttng_element_command_output);
 184                 if (ret) {
 185                         ret = CMD_ERROR;
 186                         goto end;
 187                 }
 188
 189                 /*
 190                  * Open sessions element
 191                  * For validation purpose
 192                  */
 193                 ret = mi_lttng_writer_open_element(writer,
 194                         config_element_sessions);
 195                 if (ret) {
 196                         ret = CMD_ERROR;
 197                         goto end;
 198                 }
 199         }
 200
 201         command_ret = start_tracing();
 202         if (command_ret) {
 203                 success = 0;
 204         }
 205
 206         /* Mi closing */
 207         if (lttng_opt_mi) {
 208                 /* Close  sessions and output element */
 209                 ret = mi_lttng_close_multi_element(writer, 2);
 210                 if (ret) {
 211                         ret = CMD_ERROR;
 212                         goto end;
 213                 }
 214
 215                 /* Success ? */
 216                 ret = mi_lttng_writer_write_element_bool(writer,
 217                                 mi_lttng_element_command_success, success);
 218                 if (ret) {
 219                         ret = CMD_ERROR;
 220                         goto end;
 221                 }
 222
 223                 /* Command element close */
 224                 ret = mi_lttng_writer_command_close(writer);
 225                 if (ret) {
 226                         ret = CMD_ERROR;
 227                         goto end;
 228                 }
 229         }
 230
 231 end:
 232         /* Mi clean-up */
 233         if (writer && mi_lttng_writer_destroy(writer)) {
 234                 /* Preserve original error code */
 235                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 236         }
 237
 238         /* Overwrite ret if an error occurred with start_tracing */
 239         ret = command_ret ? command_ret : ret;
 240         poptFreeContext(pc);
 241         return ret;
 242 }