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 enum {
  35         OPT_HELP = 1,
  36         OPT_LIST_OPTIONS,
  37 };
  38
  39 static struct mi_writer *writer;
  40
  41 static struct poptOption long_options[] = {
  42         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  43         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  44         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  45         {0, 0, 0, 0, 0, 0, 0}
  46 };
  47
  48 /*
  49  * Print the necessary mi for a session and name.
  50  */
  51 static int mi_print(char *session_name)
  52 {
  53         int ret;
  54
  55         assert(writer);
  56         assert(session_name);
  57
  58         /*
  59          * Open a sessions element
  60          * This is purely for validation purpose
  61          */
  62         ret = mi_lttng_sessions_open(writer);
  63         if (ret) {
  64                 goto end;
  65         }
  66
  67         /* Open a session element */
  68         ret = mi_lttng_writer_open_element(writer, config_element_session);
  69         if (ret) {
  70                 goto end;
  71         }
  72
  73         /* Session name */
  74         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  75                         session_name);
  76         if (ret) {
  77                 goto end;
  78         }
  79
  80         /* Close session and sessions element */
  81         ret = mi_lttng_close_multi_element(writer, 2);
  82         if (ret) {
  83                 goto end;
  84         }
  85 end:
  86         return ret;
  87 }
  88
  89 /*
  90  *  set_session
  91  */
  92 static int set_session(void)
  93 {
  94         int ret = CMD_SUCCESS;
  95         int count, i;
  96         unsigned int session_found = 0;
  97         struct lttng_session *sessions;
  98
  99         if (opt_session_name && strlen(opt_session_name) > NAME_MAX) {
 100                 ERR("Session name too long. Length must be lower or equal to %d",
 101                         NAME_MAX);
 102                 ret = CMD_ERROR;
 103                 goto end;
 104         }
 105
 106         count = lttng_list_sessions(&sessions);
 107         if (count < 0) {
 108                 ret = CMD_ERROR;
 109                 ERR("%s", lttng_strerror(count));
 110                 goto end;
 111         }
 112
 113         for (i = 0; i < count; i++) {
 114                 if (strncmp(sessions[i].name, opt_session_name, NAME_MAX) == 0) {
 115                         session_found = 1;
 116                         break;
 117                 }
 118         }
 119
 120         if (!session_found) {
 121                 ERR("Session '%s' not found", opt_session_name);
 122                 ret = CMD_ERROR;
 123                 goto error;
 124         }
 125
 126         ret = config_init(opt_session_name);
 127         if (ret < 0) {
 128                 ERR("Unable to set session name");
 129                 ret = CMD_ERROR;
 130                 goto error;
 131         }
 132
 133         MSG("Session set to %s", opt_session_name);
 134         if (lttng_opt_mi) {
 135                 ret = mi_print(opt_session_name);
 136                 if (ret) {
 137                         ret = CMD_ERROR;
 138                         goto error;
 139                 }
 140         }
 141
 142         ret = CMD_SUCCESS;
 143
 144 error:
 145         free(sessions);
 146 end:
 147         return ret;
 148 }
 149
 150 /*
 151  *  cmd_set_session
 152  */
 153 int cmd_set_session(int argc, const char **argv)
 154 {
 155         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 156         static poptContext pc;
 157
 158         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 159         poptReadDefaultConfig(pc, 0);
 160
 161         while ((opt = poptGetNextOpt(pc)) != -1) {
 162                 switch (opt) {
 163                 case OPT_HELP:
 164                         SHOW_HELP();
 165                         goto end;
 166                 case OPT_LIST_OPTIONS:
 167                         list_cmd_options(stdout, long_options);
 168                         goto end;
 169                 default:
 170                         ret = CMD_UNDEFINED;
 171                         goto end;
 172                 }
 173         }
 174
 175         opt_session_name = (char *) poptGetArg(pc);
 176         if (opt_session_name == NULL) {
 177                 ERR("Missing session name");
 178                 ret = CMD_ERROR;
 179                 goto end;
 180         }
 181
 182         /* Mi check */
 183         if (lttng_opt_mi) {
 184                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 185                 if (!writer) {
 186                         ret = -LTTNG_ERR_NOMEM;
 187                         goto end;
 188                 }
 189
 190                 /* Open command element */
 191                 ret = mi_lttng_writer_command_open(writer,
 192                                 mi_lttng_element_command_set_session);
 193                 if (ret) {
 194                         ret = CMD_ERROR;
 195                         goto end;
 196                 }
 197
 198                 /* Open output element */
 199                 ret = mi_lttng_writer_open_element(writer,
 200                                 mi_lttng_element_command_output);
 201                 if (ret) {
 202                         ret = CMD_ERROR;
 203                         goto end;
 204                 }
 205         }
 206
 207         command_ret = set_session();
 208         if (command_ret) {
 209                 success = 0;
 210         }
 211
 212         /* Mi closing */
 213         if (lttng_opt_mi) {
 214                 /* Close  output element */
 215                 ret = mi_lttng_writer_close_element(writer);
 216                 if (ret) {
 217                         ret = CMD_ERROR;
 218                         goto end;
 219                 }
 220
 221                 /* Success ? */
 222                 ret = mi_lttng_writer_write_element_bool(writer,
 223                                 mi_lttng_element_command_success, success);
 224                 if (ret) {
 225                         ret = CMD_ERROR;
 226                         goto end;
 227                 }
 228
 229                 /* Command element close */
 230                 ret = mi_lttng_writer_command_close(writer);
 231                 if (ret) {
 232                         ret = CMD_ERROR;
 233                         goto end;
 234                 }
 235         }
 236
 237 end:
 238         /* Mi clean-up */
 239         if (writer && mi_lttng_writer_destroy(writer)) {
 240                 /* Preserve original error code */
 241                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 242         }
 243
 244         /* Overwrite ret if an error occurred during set_session() */
 245         ret = command_ret ? command_ret : ret;
 246
 247         poptFreeContext(pc);
 248         return ret;
 249 }