src/bin/lttng/commands/start.cpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   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.hpp>
  18 #include <common/mi-lttng.hpp>
  19
  20 #include "../command.hpp"
  21
  22
  23 static struct mi_writer *writer;
  24
  25 #ifdef LTTNG_EMBED_HELP
  26 static const char help_msg[] =
  27 #include <lttng-start.1.h>
  28 ;
  29 #endif
  30
  31 enum {
  32         OPT_HELP = 1,
  33         OPT_LIST_OPTIONS,
  34 };
  35
  36 static struct poptOption long_options[] = {
  37         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  38         {"help",      'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  39         {"list-options", 0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  40         {0, 0, 0, 0, 0, 0, 0}
  41 };
  42
  43 static int mi_print_session(char *session_name, int enabled)
  44 {
  45         int ret;
  46
  47         /* Open session element */
  48         ret = mi_lttng_writer_open_element(writer, config_element_session);
  49         if (ret) {
  50                 goto end;
  51         }
  52
  53         /* Print session name element */
  54         ret = mi_lttng_writer_write_element_string(writer, config_element_name,
  55                         session_name);
  56         if (ret) {
  57                 goto end;
  58         }
  59
  60         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled,
  61                         enabled);
  62         if (ret) {
  63                 goto end;
  64         }
  65
  66         /* Close session element */
  67         ret = mi_lttng_writer_close_element(writer);
  68
  69 end:
  70         return ret;
  71 }
  72
  73 /*
  74  *  start_tracing
  75  *
  76  *  Start tracing for all trace of the session.
  77  */
  78 static int start_tracing(const char *arg_session_name)
  79 {
  80         int ret;
  81         char *session_name;
  82
  83         if (arg_session_name == NULL) {
  84                 session_name = get_session_name();
  85         } else {
  86                 session_name = strdup(arg_session_name);
  87                 if (session_name == NULL) {
  88                         PERROR("Failed to copy session name");
  89                 }
  90         }
  91
  92         if (session_name == NULL) {
  93                 ret = CMD_ERROR;
  94                 goto error;
  95         }
  96
  97         DBG("Starting tracing for session %s", session_name);
  98
  99         ret = lttng_start_tracing(session_name);
 100         if (ret < 0) {
 101                 switch (-ret) {
 102                 case LTTNG_ERR_TRACE_ALREADY_STARTED:
 103                         WARN("Tracing already started for session %s", session_name);
 104                         break;
 105                 default:
 106                         ERR("%s", lttng_strerror(ret));
 107                         break;
 108                 }
 109                 goto free_name;
 110         }
 111
 112         ret = CMD_SUCCESS;
 113
 114         MSG("Tracing started for session %s", session_name);
 115         if (lttng_opt_mi) {
 116                 ret = mi_print_session(session_name, 1);
 117                 if (ret) {
 118                         ret = CMD_ERROR;
 119                         goto free_name;
 120                 }
 121         }
 122
 123 free_name:
 124         free(session_name);
 125 error:
 126         return ret;
 127 }
 128
 129 /*
 130  *  cmd_start
 131  *
 132  *  The 'start <options>' first level command
 133  */
 134 int cmd_start(int argc, const char **argv)
 135 {
 136         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 137         static poptContext pc;
 138         const char *arg_session_name = NULL;
 139         const char *leftover = NULL;
 140
 141         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 142         poptReadDefaultConfig(pc, 0);
 143
 144         while ((opt = poptGetNextOpt(pc)) != -1) {
 145                 switch (opt) {
 146                 case OPT_HELP:
 147                         SHOW_HELP();
 148                         goto end;
 149                 case OPT_LIST_OPTIONS:
 150                         list_cmd_options(stdout, long_options);
 151                         goto end;
 152                 default:
 153                         ret = CMD_UNDEFINED;
 154                         goto end;
 155                 }
 156         }
 157
 158         arg_session_name = poptGetArg(pc);
 159
 160         leftover = poptGetArg(pc);
 161         if (leftover) {
 162                 ERR("Unknown argument: %s", leftover);
 163                 ret = CMD_ERROR;
 164                 goto end;
 165         }
 166
 167         /* Mi check */
 168         if (lttng_opt_mi) {
 169                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 170                 if (!writer) {
 171                         ret = -LTTNG_ERR_NOMEM;
 172                         goto end;
 173                 }
 174
 175                 /* Open command element */
 176                 ret = mi_lttng_writer_command_open(writer,
 177                                 mi_lttng_element_command_start);
 178                 if (ret) {
 179                         ret = CMD_ERROR;
 180                         goto end;
 181                 }
 182
 183                 /* Open output element */
 184                 ret = mi_lttng_writer_open_element(writer,
 185                                 mi_lttng_element_command_output);
 186                 if (ret) {
 187                         ret = CMD_ERROR;
 188                         goto end;
 189                 }
 190
 191                 /*
 192                  * Open sessions element
 193                  * For validation purpose
 194                  */
 195                 ret = mi_lttng_writer_open_element(writer,
 196                         config_element_sessions);
 197                 if (ret) {
 198                         ret = CMD_ERROR;
 199                         goto end;
 200                 }
 201         }
 202
 203         command_ret = start_tracing(arg_session_name);
 204         if (command_ret) {
 205                 success = 0;
 206         }
 207
 208         /* Mi closing */
 209         if (lttng_opt_mi) {
 210                 /* Close  sessions and output element */
 211                 ret = mi_lttng_close_multi_element(writer, 2);
 212                 if (ret) {
 213                         ret = CMD_ERROR;
 214                         goto end;
 215                 }
 216
 217                 /* Success ? */
 218                 ret = mi_lttng_writer_write_element_bool(writer,
 219                                 mi_lttng_element_command_success, success);
 220                 if (ret) {
 221                         ret = CMD_ERROR;
 222                         goto end;
 223                 }
 224
 225                 /* Command element close */
 226                 ret = mi_lttng_writer_command_close(writer);
 227                 if (ret) {
 228                         ret = CMD_ERROR;
 229                         goto end;
 230                 }
 231         }
 232
 233 end:
 234         /* Mi clean-up */
 235         if (writer && mi_lttng_writer_destroy(writer)) {
 236                 /* Preserve original error code */
 237                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 238         }
 239
 240         /* Overwrite ret if an error occurred with start_tracing */
 241         ret = command_ret ? command_ret : ret;
 242         poptFreeContext(pc);
 243         return ret;
 244 }