src/bin/lttng/commands/set_session.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
  11 #include <common/mi-lttng.hpp>
  12
  13 #include <popt.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <sys/stat.h>
  18 #include <sys/types.h>
  19 #include <unistd.h>
  20
  21 #ifdef LTTNG_EMBED_HELP
  22 static const char help_msg[] =
  23 #include <lttng-set-session.1.h>
  24         ;
  25 #endif
  26
  27 enum {
  28         OPT_HELP = 1,
  29         OPT_LIST_OPTIONS,
  30 };
  31
  32 static struct mi_writer *writer;
  33
  34 static struct poptOption long_options[] = {
  35         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  36         { "help", 'h', POPT_ARG_NONE, nullptr, OPT_HELP, nullptr, nullptr },
  37         { "list-options", 0, POPT_ARG_NONE, nullptr, OPT_LIST_OPTIONS, nullptr, nullptr },
  38         { nullptr, 0, 0, nullptr, 0, nullptr, nullptr }
  39 };
  40
  41 /*
  42  * Print the necessary mi for a session and name.
  43  */
  44 static int mi_print(const char *session_name)
  45 {
  46         int ret;
  47
  48         LTTNG_ASSERT(writer);
  49         LTTNG_ASSERT(session_name);
  50
  51         /*
  52          * Open a sessions element
  53          * This is purely for validation purpose
  54          */
  55         ret = mi_lttng_sessions_open(writer);
  56         if (ret) {
  57                 goto end;
  58         }
  59
  60         /* Open a session element */
  61         ret = mi_lttng_writer_open_element(writer, config_element_session);
  62         if (ret) {
  63                 goto end;
  64         }
  65
  66         /* Session name */
  67         ret = mi_lttng_writer_write_element_string(writer, config_element_name, session_name);
  68         if (ret) {
  69                 goto end;
  70         }
  71
  72         /* Close session and sessions element */
  73         ret = mi_lttng_close_multi_element(writer, 2);
  74         if (ret) {
  75                 goto end;
  76         }
  77 end:
  78         return ret;
  79 }
  80
  81 /*
  82  *  set_session
  83  */
  84 static int set_session(const char *session_name)
  85 {
  86         int ret = CMD_SUCCESS;
  87         int count, i;
  88         unsigned int session_found = 0;
  89         struct lttng_session *sessions;
  90
  91         if (session_name && strlen(session_name) > NAME_MAX) {
  92                 ERR("Session name too long. Length must be lower or equal to %d", NAME_MAX);
  93                 ret = CMD_ERROR;
  94                 goto end;
  95         }
  96
  97         count = lttng_list_sessions(&sessions);
  98         if (count < 0) {
  99                 ret = CMD_ERROR;
 100                 ERR("%s", lttng_strerror(count));
 101                 goto end;
 102         }
 103
 104         for (i = 0; i < count; i++) {
 105                 if (strncmp(sessions[i].name, session_name, NAME_MAX) == 0) {
 106                         session_found = 1;
 107                         break;
 108                 }
 109         }
 110
 111         if (!session_found) {
 112                 ERR("Session '%s' not found", session_name);
 113                 ret = CMD_ERROR;
 114                 goto error;
 115         }
 116
 117         ret = config_init(session_name);
 118         if (ret < 0) {
 119                 ERR("Unable to set session name");
 120                 ret = CMD_ERROR;
 121                 goto error;
 122         }
 123
 124         MSG("Session set to %s", session_name);
 125         if (lttng_opt_mi) {
 126                 ret = mi_print(session_name);
 127                 if (ret) {
 128                         ret = CMD_ERROR;
 129                         goto error;
 130                 }
 131         }
 132
 133         ret = CMD_SUCCESS;
 134
 135 error:
 136         free(sessions);
 137 end:
 138         return ret;
 139 }
 140
 141 /*
 142  *  cmd_set_session
 143  */
 144 int cmd_set_session(int argc, const char **argv)
 145 {
 146         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 147         static poptContext pc;
 148         const char *arg_session_name = nullptr;
 149
 150         pc = poptGetContext(nullptr, argc, argv, long_options, 0);
 151         poptReadDefaultConfig(pc, 0);
 152
 153         while ((opt = poptGetNextOpt(pc)) != -1) {
 154                 switch (opt) {
 155                 case OPT_HELP:
 156                         SHOW_HELP();
 157                         goto end;
 158                 case OPT_LIST_OPTIONS:
 159                         list_cmd_options(stdout, long_options);
 160                         goto end;
 161                 default:
 162                         ret = CMD_UNDEFINED;
 163                         goto end;
 164                 }
 165         }
 166
 167         arg_session_name = poptGetArg(pc);
 168         if (arg_session_name == nullptr) {
 169                 ERR("Missing session name");
 170                 ret = CMD_ERROR;
 171                 goto end;
 172         }
 173
 174         /* Mi check */
 175         if (lttng_opt_mi) {
 176                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 177                 if (!writer) {
 178                         ret = -LTTNG_ERR_NOMEM;
 179                         goto end;
 180                 }
 181
 182                 /* Open command element */
 183                 ret = mi_lttng_writer_command_open(writer, mi_lttng_element_command_set_session);
 184                 if (ret) {
 185                         ret = CMD_ERROR;
 186                         goto end;
 187                 }
 188
 189                 /* Open output element */
 190                 ret = mi_lttng_writer_open_element(writer, mi_lttng_element_command_output);
 191                 if (ret) {
 192                         ret = CMD_ERROR;
 193                         goto end;
 194                 }
 195         }
 196
 197         command_ret = set_session(arg_session_name);
 198         if (command_ret) {
 199                 success = 0;
 200         }
 201
 202         /* Mi closing */
 203         if (lttng_opt_mi) {
 204                 /* Close  output element */
 205                 ret = mi_lttng_writer_close_element(writer);
 206                 if (ret) {
 207                         ret = CMD_ERROR;
 208                         goto end;
 209                 }
 210
 211                 /* Success ? */
 212                 ret = mi_lttng_writer_write_element_bool(
 213                         writer, 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 during set_session() */
 235         ret = command_ret ? command_ret : ret;
 236
 237         poptFreeContext(pc);
 238         return ret;
 239 }