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 enum {
  25         OPT_HELP = 1,
  26         OPT_LIST_OPTIONS,
  27         OPT_ENABLE_GLOB,
  28         OPT_ALL,
  29 };
  30
  31 namespace {
  32 struct mi_writer *writer;
  33
  34 #ifdef LTTNG_EMBED_HELP
  35 const char help_msg[] =
  36 #include <lttng-start.1.h>
  37         ;
  38 #endif
  39
  40 struct poptOption long_options[] = {
  41         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  42         { "help", 'h', POPT_ARG_NONE, nullptr, OPT_HELP, nullptr, nullptr },
  43         { "list-options", 0, POPT_ARG_NONE, nullptr, OPT_LIST_OPTIONS, nullptr, nullptr },
  44         { "glob", 'g', POPT_ARG_NONE, nullptr, OPT_ENABLE_GLOB, nullptr, nullptr },
  45         { "all", 'a', POPT_ARG_NONE, nullptr, OPT_ALL, nullptr, nullptr },
  46         { nullptr, 0, 0, nullptr, 0, nullptr, nullptr }
  47 };
  48
  49 int mi_print_session(const char *session_name, int enabled)
  50 {
  51         int ret;
  52
  53         /* Open session element */
  54         ret = mi_lttng_writer_open_element(writer, config_element_session);
  55         if (ret) {
  56                 goto end;
  57         }
  58
  59         /* Print session name element */
  60         ret = mi_lttng_writer_write_element_string(writer, config_element_name, session_name);
  61         if (ret) {
  62                 goto end;
  63         }
  64
  65         ret = mi_lttng_writer_write_element_bool(writer, config_element_enabled, enabled);
  66         if (ret) {
  67                 goto end;
  68         }
  69
  70         /* Close session element */
  71         ret = mi_lttng_writer_close_element(writer);
  72
  73 end:
  74         return ret;
  75 }
  76
  77 /*
  78  *  start_tracing
  79  *
  80  *  Start tracing for all trace of the session.
  81  */
  82 int start_tracing(const char *session_name)
  83 {
  84         int ret;
  85
  86         if (session_name == nullptr) {
  87                 ret = CMD_ERROR;
  88                 goto error;
  89         }
  90
  91         DBG("Starting tracing for session %s", session_name);
  92
  93         ret = lttng_start_tracing(session_name);
  94         if (ret < 0) {
  95                 switch (-ret) {
  96                 case LTTNG_ERR_TRACE_ALREADY_STARTED:
  97                         WARN("Tracing already started for session %s", session_name);
  98                         break;
  99                 default:
 100                         ERR("%s", lttng_strerror(ret));
 101                         break;
 102                 }
 103                 goto error;
 104         }
 105
 106         ret = CMD_SUCCESS;
 107
 108         MSG("Tracing started for session %s", session_name);
 109         if (lttng_opt_mi) {
 110                 ret = mi_print_session(session_name, 1);
 111                 if (ret) {
 112                         ret = CMD_ERROR;
 113                         goto error;
 114                 }
 115         }
 116
 117 error:
 118         return ret;
 119 }
 120
 121 int start_tracing(const struct session_spec& spec)
 122 {
 123         int ret = CMD_SUCCESS;
 124         bool had_warning = false;
 125
 126         try {
 127                 for (const auto& session : list_sessions(spec)) {
 128                         const auto sub_ret = start_tracing(session.name);
 129
 130                         switch (sub_ret) {
 131                         case CMD_WARNING:
 132                                 had_warning = true;
 133                                 /* fall-through. */
 134                         case CMD_SUCCESS:
 135                                 continue;
 136                         default:
 137                                 ret = sub_ret;
 138                                 break;
 139                         }
 140                 }
 141         } catch (const std::exception& e) {
 142                 ERR_FMT("{}", e.what());
 143                 return CMD_FATAL;
 144         }
 145
 146         if (ret == CMD_SUCCESS && had_warning) {
 147                 ret = CMD_WARNING;
 148         }
 149
 150         return ret;
 151 }
 152 } /* namespace */
 153
 154 /*
 155  *  cmd_start
 156  *
 157  *  The 'start <options>' first level command
 158  */
 159 int cmd_start(int argc, const char **argv)
 160 {
 161         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 162         static poptContext pc;
 163         const char *leftover = nullptr;
 164         struct session_spec session_spec = {
 165                 .type = session_spec::NAME,
 166                 .value = nullptr,
 167         };
 168
 169         pc = poptGetContext(nullptr, argc, argv, long_options, 0);
 170         poptReadDefaultConfig(pc, 0);
 171
 172         while ((opt = poptGetNextOpt(pc)) != -1) {
 173                 switch (opt) {
 174                 case OPT_HELP:
 175                         SHOW_HELP();
 176                         goto end;
 177                 case OPT_LIST_OPTIONS:
 178                         list_cmd_options(stdout, long_options);
 179                         goto end;
 180                 case OPT_ENABLE_GLOB:
 181                         session_spec.type = session_spec::GLOB_PATTERN;
 182                         break;
 183                 case OPT_ALL:
 184                         session_spec.type = session_spec::ALL;
 185                         break;
 186                 default:
 187                         ret = CMD_UNDEFINED;
 188                         goto end;
 189                 }
 190         }
 191
 192         session_spec.value = poptGetArg(pc);
 193
 194         leftover = poptGetArg(pc);
 195         if (leftover) {
 196                 ERR("Unknown argument: %s", leftover);
 197                 ret = CMD_ERROR;
 198                 goto end;
 199         }
 200
 201         /* Mi check */
 202         if (lttng_opt_mi) {
 203                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 204                 if (!writer) {
 205                         ret = -LTTNG_ERR_NOMEM;
 206                         goto end;
 207                 }
 208
 209                 /* Open command element */
 210                 ret = mi_lttng_writer_command_open(writer, mi_lttng_element_command_start);
 211                 if (ret) {
 212                         ret = CMD_ERROR;
 213                         goto end;
 214                 }
 215
 216                 /* Open output element */
 217                 ret = mi_lttng_writer_open_element(writer, mi_lttng_element_command_output);
 218                 if (ret) {
 219                         ret = CMD_ERROR;
 220                         goto end;
 221                 }
 222
 223                 /*
 224                  * Open sessions element
 225                  * For validation purpose
 226                  */
 227                 ret = mi_lttng_writer_open_element(writer, config_element_sessions);
 228                 if (ret) {
 229                         ret = CMD_ERROR;
 230                         goto end;
 231                 }
 232         }
 233
 234         command_ret = start_tracing(session_spec);
 235         if (command_ret) {
 236                 success = 0;
 237         }
 238
 239         /* Mi closing */
 240         if (lttng_opt_mi) {
 241                 /* Close  sessions and output element */
 242                 ret = mi_lttng_close_multi_element(writer, 2);
 243                 if (ret) {
 244                         ret = CMD_ERROR;
 245                         goto end;
 246                 }
 247
 248                 /* Success ? */
 249                 ret = mi_lttng_writer_write_element_bool(
 250                         writer, mi_lttng_element_command_success, success);
 251                 if (ret) {
 252                         ret = CMD_ERROR;
 253                         goto end;
 254                 }
 255
 256                 /* Command element close */
 257                 ret = mi_lttng_writer_command_close(writer);
 258                 if (ret) {
 259                         ret = CMD_ERROR;
 260                         goto end;
 261                 }
 262         }
 263
 264 end:
 265         /* Mi clean-up */
 266         if (writer && mi_lttng_writer_destroy(writer)) {
 267                 /* Preserve original error code */
 268                 ret = ret ? ret : -LTTNG_ERR_MI_IO_FAIL;
 269         }
 270
 271         /* Overwrite ret if an error occurred with start_tracing */
 272         ret = command_ret ? command_ret : ret;
 273         poptFreeContext(pc);
 274         return ret;
 275 }