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 "../command.hpp"
  10 #include "../utils.hpp"
  11
  12 #include <common/exception.hpp>
  13 #include <common/mi-lttng.hpp>
  14 #include <common/sessiond-comm/sessiond-comm.hpp>
  15
  16 #include <popt.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <sys/stat.h>
  21 #include <sys/types.h>
  22 #include <unistd.h>
  23
  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         OPT_ENABLE_GLOB,
  36         OPT_ALL,
  37 };
  38
  39 static struct poptOption long_options[] = {
  40         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  41         { "help", 'h', POPT_ARG_NONE, nullptr, OPT_HELP, nullptr, nullptr },
  42         { "list-options", 0, POPT_ARG_NONE, nullptr, OPT_LIST_OPTIONS, nullptr, nullptr },
  43         { "glob", 'g', POPT_ARG_NONE, nullptr, OPT_ENABLE_GLOB, nullptr, nullptr },
  44         { "all", 'a', POPT_ARG_NONE, nullptr, OPT_ALL, nullptr, nullptr },
  45         { nullptr, 0, 0, nullptr, 0, nullptr, nullptr }
  46 };
  47
  48 static int mi_print_session(const 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, session_name);
  60         if (ret) {
  61                 goto end;
  62         }
  63
  64         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled, enabled);
  65         if (ret) {
  66                 goto end;
  67         }
  68
  69         /* Close session element */
  70         ret = mi_lttng_writer_close_element(writer);
  71
  72 end:
  73         return ret;
  74 }
  75
  76 /*
  77  *  start_tracing
  78  *
  79  *  Start tracing for all trace of the session.
  80  */
  81 static int start_tracing(const char *session_name)
  82 {
  83         int ret;
  84
  85         if (session_name == nullptr) {
  86                 ret = CMD_ERROR;
  87                 goto error;
  88         }
  89
  90         DBG("Starting tracing for session %s", session_name);
  91
  92         ret = lttng_start_tracing(session_name);
  93         if (ret < 0) {
  94                 switch (-ret) {
  95                 case LTTNG_ERR_TRACE_ALREADY_STARTED:
  96                         WARN("Tracing already started for session %s", session_name);
  97                         break;
  98                 default:
  99                         ERR("%s", lttng_strerror(ret));
 100                         break;
 101                 }
 102                 goto error;
 103         }
 104
 105         ret = CMD_SUCCESS;
 106
 107         MSG("Tracing started for session %s", session_name);
 108         if (lttng_opt_mi) {
 109                 ret = mi_print_session(session_name, 1);
 110                 if (ret) {
 111                         ret = CMD_ERROR;
 112                         goto error;
 113                 }
 114         }
 115
 116 error:
 117         return ret;
 118 }
 119
 120 static int start_tracing(const struct session_spec& spec)
 121 {
 122         int ret = CMD_SUCCESS;
 123         bool had_warning = false;
 124
 125         try {
 126                 for (const auto& session : list_sessions(spec)) {
 127                         const auto sub_ret = start_tracing(session.name);
 128
 129                         switch (sub_ret) {
 130                         case CMD_WARNING:
 131                                 had_warning = true;
 132                                 /* fall-through. */
 133                         case CMD_SUCCESS:
 134                                 continue;
 135                         default:
 136                                 ret = sub_ret;
 137                                 break;
 138                         }
 139                 }
 140         } catch (const std::exception& e) {
 141                 ERR_FMT("{}", e.what());
 142                 return CMD_FATAL;
 143         }
 144
 145         if (ret == CMD_SUCCESS && had_warning) {
 146                 ret = CMD_WARNING;
 147         }
 148
 149         return ret;
 150 }
 151
 152 /*
 153  *  cmd_start
 154  *
 155  *  The 'start <options>' first level command
 156  */
 157 int cmd_start(int argc, const char **argv)
 158 {
 159         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 160         static poptContext pc;
 161         const char *leftover = nullptr;
 162         struct session_spec session_spec = {
 163                 .type = session_spec::NAME,
 164                 .value = nullptr,
 165         };
 166
 167         pc = poptGetContext(nullptr, argc, argv, long_options, 0);
 168         poptReadDefaultConfig(pc, 0);
 169
 170         while ((opt = poptGetNextOpt(pc)) != -1) {
 171                 switch (opt) {
 172                 case OPT_HELP:
 173                         SHOW_HELP();
 174                         goto end;
 175                 case OPT_LIST_OPTIONS:
 176                         list_cmd_options(stdout, long_options);
 177                         goto end;
 178                 case OPT_ENABLE_GLOB:
 179                         session_spec.type = session_spec::GLOB_PATTERN;
 180                         break;
 181                 case OPT_ALL:
 182                         session_spec.type = session_spec::ALL;
 183                         break;
 184                 default:
 185                         ret = CMD_UNDEFINED;
 186                         goto end;
 187                 }
 188         }
 189
 190         session_spec.value = poptGetArg(pc);
 191
 192         leftover = poptGetArg(pc);
 193         if (leftover) {
 194                 ERR("Unknown argument: %s", leftover);
 195                 ret = CMD_ERROR;
 196                 goto end;
 197         }
 198
 199         /* Mi check */
 200         if (lttng_opt_mi) {
 201                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 202                 if (!writer) {
 203                         ret = -LTTNG_ERR_NOMEM;
 204                         goto end;
 205                 }
 206
 207                 /* Open command element */
 208                 ret = mi_lttng_writer_command_open(writer, mi_lttng_element_command_start);
 209                 if (ret) {
 210                         ret = CMD_ERROR;
 211                         goto end;
 212                 }
 213
 214                 /* Open output element */
 215                 ret = mi_lttng_writer_open_element(writer, mi_lttng_element_command_output);
 216                 if (ret) {
 217                         ret = CMD_ERROR;
 218                         goto end;
 219                 }
 220
 221                 /*
 222                  * Open sessions element
 223                  * For validation purpose
 224                  */
 225                 ret = mi_lttng_writer_open_element(writer, config_element_sessions);
 226                 if (ret) {
 227                         ret = CMD_ERROR;
 228                         goto end;
 229                 }
 230         }
 231
 232         command_ret = start_tracing(session_spec);
 233         if (command_ret) {
 234                 success = 0;
 235         }
 236
 237         /* Mi closing */
 238         if (lttng_opt_mi) {
 239                 /* Close  sessions and output element */
 240                 ret = mi_lttng_close_multi_element(writer, 2);
 241                 if (ret) {
 242                         ret = CMD_ERROR;
 243                         goto end;
 244                 }
 245
 246                 /* Success ? */
 247                 ret = mi_lttng_writer_write_element_bool(
 248                         writer, mi_lttng_element_command_success, success);
 249                 if (ret) {
 250                         ret = CMD_ERROR;
 251                         goto end;
 252                 }
 253
 254                 /* Command element close */
 255                 ret = mi_lttng_writer_command_close(writer);
 256                 if (ret) {
 257                         ret = CMD_ERROR;
 258                         goto end;
 259                 }
 260         }
 261
 262 end:
 263         /* Mi clean-up */
 264         if (writer && mi_lttng_writer_destroy(writer)) {
 265                 /* Preserve original error code */
 266                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 267         }
 268
 269         /* Overwrite ret if an error occurred with start_tracing */
 270         ret = command_ret ? command_ret : ret;
 271         poptFreeContext(pc);
 272         return ret;
 273 }