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 _GNU_SOURCE
  19 #define _LGPL_SOURCE
  20 #include <popt.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/stat.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27 #include <assert.h>
  28
  29 #include <common/mi-lttng.h>
  30
  31 #include "../command.h"
  32
  33 static char *opt_session_name;
  34
  35 enum {
  36         OPT_HELP = 1,
  37         OPT_LIST_OPTIONS,
  38 };
  39
  40 static struct mi_writer *writer;
  41
  42 static struct poptOption long_options[] = {
  43         /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
  44         {"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
  45         {"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
  46         {0, 0, 0, 0, 0, 0, 0}
  47 };
  48
  49 /*
  50  * usage
  51  */
  52 static void usage(FILE *ofp)
  53 {
  54         fprintf(ofp, "usage: lttng set-session NAME [OPTIONS]\n");
  55         fprintf(ofp, "\n");
  56         fprintf(ofp, "Options:\n");
  57         fprintf(ofp, "  -h, --help               Show this help\n");
  58         fprintf(ofp, "      --list-options       Simple listing of options\n");
  59         fprintf(ofp, "\n");
  60 }
  61
  62 /*
  63  * Print the necessary mi for a session and name.
  64  */
  65 static int mi_print(char *session_name)
  66 {
  67         int ret;
  68
  69         assert(writer);
  70         assert(session_name);
  71
  72         /*
  73          * Open a sessions element
  74          * This is purely for validation purpose
  75          */
  76         ret = mi_lttng_sessions_open(writer);
  77         if (ret) {
  78                 goto end;
  79         }
  80
  81         /* Open a session element */
  82         ret = mi_lttng_writer_open_element(writer, config_element_session);
  83         if (ret) {
  84                 goto end;
  85         }
  86
  87         /* Session name */
  88         ret = mi_lttng_writer_write_element_string(writer , config_element_name,
  89                         session_name);
  90         if (ret) {
  91                 goto end;
  92         }
  93
  94         /* Close session and sessions element */
  95         ret = mi_lttng_close_multi_element(writer, 2);
  96         if (ret) {
  97                 goto end;
  98         }
  99 end:
 100         return ret;
 101 }
 102
 103 /*
 104  *  set_session
 105  */
 106 static int set_session(void)
 107 {
 108         int ret = CMD_SUCCESS;
 109         int count, i;
 110         unsigned int session_found = 0;
 111         struct lttng_session *sessions;
 112
 113         if (opt_session_name && strlen(opt_session_name) > NAME_MAX) {
 114                 ERR("Session name too long. Length must be lower or equal to %d",
 115                         NAME_MAX);
 116                 ret = CMD_ERROR;
 117                 goto end;
 118         }
 119
 120         count = lttng_list_sessions(&sessions);
 121         if (count < 0) {
 122                 ret = CMD_ERROR;
 123                 ERR("%s", lttng_strerror(count));
 124                 goto end;
 125         }
 126
 127         for (i = 0; i < count; i++) {
 128                 if (strncmp(sessions[i].name, opt_session_name, NAME_MAX) == 0) {
 129                         session_found = 1;
 130                         break;
 131                 }
 132         }
 133
 134         if (!session_found) {
 135                 ERR("Session '%s' not found", opt_session_name);
 136                 ret = CMD_ERROR;
 137                 goto error;
 138         }
 139
 140         ret = config_init(opt_session_name);
 141         if (ret < 0) {
 142                 ERR("Unable to set session name");
 143                 ret = CMD_ERROR;
 144                 goto error;
 145         }
 146
 147         MSG("Session set to %s", opt_session_name);
 148         if (lttng_opt_mi) {
 149                 ret = mi_print(opt_session_name);
 150                 if (ret) {
 151                         ret = CMD_ERROR;
 152                         goto error;
 153                 }
 154         }
 155
 156         ret = CMD_SUCCESS;
 157
 158 error:
 159         free(sessions);
 160 end:
 161         return ret;
 162 }
 163
 164 /*
 165  *  cmd_set_session
 166  */
 167 int cmd_set_session(int argc, const char **argv)
 168 {
 169         int opt, ret = CMD_SUCCESS, command_ret = CMD_SUCCESS, success = 1;
 170         static poptContext pc;
 171
 172         pc = poptGetContext(NULL, argc, argv, long_options, 0);
 173         poptReadDefaultConfig(pc, 0);
 174
 175         while ((opt = poptGetNextOpt(pc)) != -1) {
 176                 switch (opt) {
 177                 case OPT_HELP:
 178                         usage(stdout);
 179                         goto end;
 180                 case OPT_LIST_OPTIONS:
 181                         list_cmd_options(stdout, long_options);
 182                         goto end;
 183                 default:
 184                         usage(stderr);
 185                         ret = CMD_UNDEFINED;
 186                         goto end;
 187                 }
 188         }
 189
 190         opt_session_name = (char *) poptGetArg(pc);
 191         if (opt_session_name == NULL) {
 192                 ERR("Missing session name");
 193                 usage(stderr);
 194                 ret = CMD_ERROR;
 195                 goto end;
 196         }
 197
 198         /* Mi check */
 199         if (lttng_opt_mi) {
 200                 writer = mi_lttng_writer_create(fileno(stdout), lttng_opt_mi);
 201                 if (!writer) {
 202                         ret = -LTTNG_ERR_NOMEM;
 203                         goto end;
 204                 }
 205
 206                 /* Open command element */
 207                 ret = mi_lttng_writer_command_open(writer,
 208                                 mi_lttng_element_command_set_session);
 209                 if (ret) {
 210                         ret = CMD_ERROR;
 211                         goto end;
 212                 }
 213
 214                 /* Open output element */
 215                 ret = mi_lttng_writer_open_element(writer,
 216                                 mi_lttng_element_command_output);
 217                 if (ret) {
 218                         ret = CMD_ERROR;
 219                         goto end;
 220                 }
 221         }
 222
 223         command_ret = set_session();
 224         if (command_ret) {
 225                 success = 0;
 226         }
 227
 228         /* Mi closing */
 229         if (lttng_opt_mi) {
 230                 /* Close  output element */
 231                 ret = mi_lttng_writer_close_element(writer);
 232                 if (ret) {
 233                         ret = CMD_ERROR;
 234                         goto end;
 235                 }
 236
 237                 /* Success ? */
 238                 ret = mi_lttng_writer_write_element_bool(writer,
 239                                 mi_lttng_element_command_success, success);
 240                 if (ret) {
 241                         ret = CMD_ERROR;
 242                         goto end;
 243                 }
 244
 245                 /* Command element close */
 246                 ret = mi_lttng_writer_command_close(writer);
 247                 if (ret) {
 248                         ret = CMD_ERROR;
 249                         goto end;
 250                 }
 251         }
 252
 253 end:
 254         /* Mi clean-up */
 255         if (writer && mi_lttng_writer_destroy(writer)) {
 256                 /* Preserve original error code */
 257                 ret = ret ? ret : LTTNG_ERR_MI_IO_FAIL;
 258         }
 259
 260         /* Overwrite ret if an error occured during set_session() */
 261         ret = command_ret ? command_ret : ret;
 262
 263         poptFreeContext(pc);
 264         return ret;
 265 }