src/bin/lttng/commands/set_session.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <popt.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26 #include <assert.h>
  27
  28 #include <common/mi-lttng.h>
  29
  30 #include "../command.h"
  31
  32 static char *opt_session_name;
  33
  34 #ifdef LTTNG_EMBED_HELP
  35 static const char help_msg[] =
  36 #include <lttng-set-session.1.h>
  37 ;
  38 #endif
  39
  40 enum {
  41         OPT_HELP = 1,
  42         OPT_LIST_OPTIONS,
  43 };
  44
  45 static struct mi_writer *writer;
  46
  47 static struct poptOption long_options[] = {
  48         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  49         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  50         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  51         {0, 0, 0, 0, 0, 0, 0}
  52 };
  53
  54 /*
  55  * Print the necessary mi for a session and name.
  56  */
  57 static int mi_print(char *session_name)
  58 {
  59         int ret;
  60
  61         assert(writer);
  62         assert(session_name);
  63
  64         /*
  65          * Open a sessions element
  66          * This is purely for validation purpose
  67          */
  68         ret = mi_lttng_sessions_open(writer);
  69         if (ret) {
  70                 goto end;
  71         }
  72
  73         /* Open a session element */
  74         ret = mi_lttng_writer_open_element(writer, config_element_session);
  75         if (ret) {
  76                 goto end;
  77         }
  78
  79         /* Session name */
  80         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  81                         session_name);
  82         if (ret) {
  83                 goto end;
  84         }
  85
  86         /* Close session and sessions element */
  87         ret = mi_lttng_close_multi_element(writer, 2);
  88         if (ret) {
  89                 goto end;
  90         }
  91 end:
  92         return ret;
  93 }
  94
  95 /*
  96  *  set_session
  97  */
  98 static int set_session(void)
  99 {
 100         int ret = CMD_SUCCESS;
 101         int count, i;
 102         unsigned int session_found = 0;
 103         struct lttng_session *sessions;
 104
 105         if (opt_session_name && strlen(opt_session_name) > NAME_MAX) {
 106                 ERR("Session name too long. Length must be lower or equal to %d",
 107                         NAME_MAX);
 108                 ret = CMD_ERROR;
 109                 goto end;
 110         }
 111
 112         count = lttng_list_sessions(&sessions);
 113         if (count < 0) {
 114                 ret = CMD_ERROR;
 115                 ERR("%s", lttng_strerror(count));
 116                 goto end;
 117         }
 118
 119         for (i = 0; i < count; i++) {
 120                 if (strncmp(sessions[i].name, opt_session_name, NAME_MAX) == 0) {
 121                         session_found = 1;
 122                         break;
 123                 }
 124         }
 125
 126         if (!session_found) {
 127                 ERR("Session '%s' not found", opt_session_name);
 128                 ret = CMD_ERROR;
 129                 goto error;
 130         }
 131
 132         ret = config_init(opt_session_name);
 133         if (ret < 0) {
 134                 ERR("Unable to set session name");
 135                 ret = CMD_ERROR;
 136                 goto error;
 137         }
 138
 139         MSG("Session set to %s", opt_session_name);
 140         if (lttng_opt_mi) {
 141                 ret = mi_print(opt_session_name);
 142                 if (ret) {
 143                         ret = CMD_ERROR;
 144                         goto error;
 145                 }
 146         }
 147
 148         ret = CMD_SUCCESS;
 149
 150 error:
 151         free(sessions);
 152 end:
 153         return ret;
 154 }
 155
 156 /*
 157  *  cmd_set_session
 158  */
 159 int cmd_set_session(int argc, const char **argv)
 160 {
 161         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 162         static poptContext pc;
 163
 164         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 165         poptReadDefaultConfig(pc, 0);
 166
 167         while ((opt = poptGetNextOpt(pc)) != -1) {
 168                 switch (opt) {
 169                 case OPT_HELP:
 170                         SHOW_HELP();
 171                         goto end;
 172                 case OPT_LIST_OPTIONS:
 173                         list_cmd_options(stdout, long_options);
 174                         goto end;
 175                 default:
 176                         ret = CMD_UNDEFINED;
 177                         goto end;
 178                 }
 179         }
 180
 181         opt_session_name = (char *) poptGetArg(pc);
 182         if (opt_session_name == NULL) {
 183                 ERR("Missing session name");
 184                 ret = CMD_ERROR;
 185                 goto end;
 186         }
 187
 188         /* Mi check */
 189         if (lttng_opt_mi) {
 190                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 191                 if (!writer) {
 192                         ret = -LTTNG_ERR_NOMEM;
 193                         goto end;
 194                 }
 195
 196                 /* Open command element */
 197                 ret = mi_lttng_writer_command_open(writer,
 198                                 mi_lttng_element_command_set_session);
 199                 if (ret) {
 200                         ret = CMD_ERROR;
 201                         goto end;
 202                 }
 203
 204                 /* Open output element */
 205                 ret = mi_lttng_writer_open_element(writer,
 206                                 mi_lttng_element_command_output);
 207                 if (ret) {
 208                         ret = CMD_ERROR;
 209                         goto end;
 210                 }
 211         }
 212
 213         command_ret = set_session();
 214         if (command_ret) {
 215                 success = 0;
 216         }
 217
 218         /* Mi closing */
 219         if (lttng_opt_mi) {
 220                 /* Close  output element */
 221                 ret = mi_lttng_writer_close_element(writer);
 222                 if (ret) {
 223                         ret = CMD_ERROR;
 224                         goto end;
 225                 }
 226
 227                 /* Success ? */
 228                 ret = mi_lttng_writer_write_element_bool(writer,
 229                                 mi_lttng_element_command_success, success);
 230                 if (ret) {
 231                         ret = CMD_ERROR;
 232                         goto end;
 233                 }
 234
 235                 /* Command element close */
 236                 ret = mi_lttng_writer_command_close(writer);
 237                 if (ret) {
 238                         ret = CMD_ERROR;
 239                         goto end;
 240                 }
 241         }
 242
 243 end:
 244         /* Mi clean-up */
 245         if (writer && mi_lttng_writer_destroy(writer)) {
 246                 /* Preserve original error code */
 247                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 248         }
 249
 250         /* Overwrite ret if an error occurred during set_session() */
 251         ret = command_ret ? command_ret : ret;
 252
 253         poptFreeContext(pc);
 254         return ret;
 255 }