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  * usage
  50  */
  51 static void usage(FILE *ofp)
  52 {
  53         fprintf(ofp, "usage: lttng set-session NAME [OPTIONS]\n");
  54         fprintf(ofp, "\n");
  55         fprintf(ofp, "Options:\n");
  56         fprintf(ofp, "  -h, --help               Show this help\n");
  57         fprintf(ofp, "      --list-options       Simple listing of options\n");
  58         fprintf(ofp, "\n");
  59 }
  60
  61 /*
  62  * Print the necessary mi for a session and name.
  63  */
  64 static int mi_print(char *session_name)
  65 {
  66         int ret;
  67
  68         assert(writer);
  69         assert(session_name);
  70
  71         /*
  72          * Open a sessions element
  73          * This is purely for validation purpose
  74          */
  75         ret = mi_lttng_sessions_open(writer);
  76         if (ret) {
  77                 goto end;
  78         }
  79
  80         /* Open a session element */
  81         ret = mi_lttng_writer_open_element(writer, config_element_session);
  82         if (ret) {
  83                 goto end;
  84         }
  85
  86         /* Session name */
  87         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  88                         session_name);
  89         if (ret) {
  90                 goto end;
  91         }
  92
  93         /* Close session and sessions element */
  94         ret = mi_lttng_close_multi_element(writer, 2);
  95         if (ret) {
  96                 goto end;
  97         }
  98 end:
  99         return ret;
 100 }
 101
 102 /*
 103  *  set_session
 104  */
 105 static int set_session(void)
 106 {
 107         int ret = CMD_SUCCESS;
 108         int count, i;
 109         unsigned int session_found = 0;
 110         struct lttng_session *sessions;
 111
 112         if (opt_session_name && strlen(opt_session_name) > NAME_MAX) {
 113                 ERR("Session name too long. Length must be lower or equal to %d",
 114                         NAME_MAX);
 115                 ret = CMD_ERROR;
 116                 goto end;
 117         }
 118
 119         count = lttng_list_sessions(&sessions);
 120         if (count < 0) {
 121                 ret = CMD_ERROR;
 122                 ERR("%s", lttng_strerror(count));
 123                 goto end;
 124         }
 125
 126         for (i = 0; i < count; i++) {
 127                 if (strncmp(sessions[i].name, opt_session_name, NAME_MAX) == 0) {
 128                         session_found = 1;
 129                         break;
 130                 }
 131         }
 132
 133         if (!session_found) {
 134                 ERR("Session '%s' not found", opt_session_name);
 135                 ret = CMD_ERROR;
 136                 goto error;
 137         }
 138
 139         ret = config_init(opt_session_name);
 140         if (ret < 0) {
 141                 ERR("Unable to set session name");
 142                 ret = CMD_ERROR;
 143                 goto error;
 144         }
 145
 146         MSG("Session set to %s", opt_session_name);
 147         if (lttng_opt_mi) {
 148                 ret = mi_print(opt_session_name);
 149                 if (ret) {
 150                         ret = CMD_ERROR;
 151                         goto error;
 152                 }
 153         }
 154
 155         ret = CMD_SUCCESS;
 156
 157 error:
 158         free(sessions);
 159 end:
 160         return ret;
 161 }
 162
 163 /*
 164  *  cmd_set_session
 165  */
 166 int cmd_set_session(int argc, const char **argv)
 167 {
 168         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 169         static poptContext pc;
 170
 171         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 172         poptReadDefaultConfig(pc, 0);
 173
 174         while ((opt = poptGetNextOpt(pc)) != -1) {
 175                 switch (opt) {
 176                 case OPT_HELP:
 177                         usage(stdout);
 178                         goto end;
 179                 case OPT_LIST_OPTIONS:
 180                         list_cmd_options(stdout, long_options);
 181                         goto end;
 182                 default:
 183                         usage(stderr);
 184                         ret = CMD_UNDEFINED;
 185                         goto end;
 186                 }
 187         }
 188
 189         opt_session_name = (char *) poptGetArg(pc);
 190         if (opt_session_name == NULL) {
 191                 ERR("Missing session name");
 192                 usage(stderr);
 193                 ret = CMD_ERROR;
 194                 goto end;
 195         }
 196
 197         /* Mi check */
 198         if (lttng_opt_mi) {
 199                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 200                 if (!writer) {
 201                         ret = -LTTNG_ERR_NOMEM;
 202                         goto end;
 203                 }
 204
 205                 /* Open command element */
 206                 ret = mi_lttng_writer_command_open(writer,
 207                                 mi_lttng_element_command_set_session);
 208                 if (ret) {
 209                         ret = CMD_ERROR;
 210                         goto end;
 211                 }
 212
 213                 /* Open output element */
 214                 ret = mi_lttng_writer_open_element(writer,
 215                                 mi_lttng_element_command_output);
 216                 if (ret) {
 217                         ret = CMD_ERROR;
 218                         goto end;
 219                 }
 220         }
 221
 222         command_ret = set_session();
 223         if (command_ret) {
 224                 success = 0;
 225         }
 226
 227         /* Mi closing */
 228         if (lttng_opt_mi) {
 229                 /* Close  output element */
 230                 ret = mi_lttng_writer_close_element(writer);
 231                 if (ret) {
 232                         ret = CMD_ERROR;
 233                         goto end;
 234                 }
 235
 236                 /* Success ? */
 237                 ret = mi_lttng_writer_write_element_bool(writer,
 238                                 mi_lttng_element_command_success, success);
 239                 if (ret) {
 240                         ret = CMD_ERROR;
 241                         goto end;
 242                 }
 243
 244                 /* Command element close */
 245                 ret = mi_lttng_writer_command_close(writer);
 246                 if (ret) {
 247                         ret = CMD_ERROR;
 248                         goto end;
 249                 }
 250         }
 251
 252 end:
 253         /* Mi clean-up */
 254         if (writer && mi_lttng_writer_destroy(writer)) {
 255                 /* Preserve original error code */
 256                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 257         }
 258
 259         /* Overwrite ret if an error occured during set_session() */
 260         ret = command_ret ? command_ret : ret;
 261
 262         poptFreeContext(pc);
 263         return ret;
 264 }