lttng/conf.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 as published by
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <limits.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
  28 #include "conf.h"
  29 #include "lttngerr.h"
  30
  31 /*
  32  *  config_get_file_path
  33  *
  34  *  Return the path with '/CONFIG_FILENAME' added to it.
  35  */
  36 char *config_get_file_path(char *path)
  37 {
  38         int ret;
  39         char *file_path;
  40
  41         ret = asprintf(&file_path, "%s/%s", path, CONFIG_FILENAME);
  42         if (ret < 0) {
  43                 ERR("Fail allocating config file path");
  44         }
  45
  46         return file_path;
  47 }
  48
  49 /*
  50  *  open_config
  51  *
  52  *  Return an open FILE pointer to the config file.
  53  */
  54 static FILE *open_config(char *path, const char *mode)
  55 {
  56         FILE *fp = NULL;
  57         char *file_path;
  58
  59         file_path = config_get_file_path(path);
  60         if (file_path == NULL) {
  61                 goto error;
  62         }
  63
  64         fp = fopen(file_path, mode);
  65         if (fp == NULL) {
  66                 perror("config file");
  67                 goto error;
  68         }
  69
  70 error:
  71         if (file_path) {
  72                 free(file_path);
  73         }
  74         return fp;
  75 }
  76
  77 /*
  78  *  create_config_file
  79  *
  80  *  Create the empty config file a the path.
  81  */
  82 static int create_config_file(char *path)
  83 {
  84         int ret;
  85         FILE *fp;
  86
  87         fp = open_config(path, "w+");
  88         if (fp == NULL) {
  89                 ERR("Unable to create config file");
  90                 ret = -1;
  91                 goto error;
  92         }
  93
  94         ret = fclose(fp);
  95
  96 error:
  97         return ret;
  98 }
  99
 100 /*
 101  *  write_config
 102  *
 103  *  Append data to the config file in file_path
 104  */
 105 static int write_config(char *file_path, size_t size, char *data)
 106 {
 107         FILE *fp;
 108         size_t len;
 109         int ret = 0;
 110
 111         fp = open_config(file_path, "a");
 112         if (fp == NULL) {
 113                 ret = -1;
 114                 goto end;
 115         }
 116
 117         /* Write session name into config file */
 118         len = fwrite(data, size, 1, fp);
 119         if (len < 1) {
 120                 ret = -1;
 121         }
 122         fclose(fp);
 123 end:
 124         return ret;
 125 }
 126
 127 /*
 128  *  config_get_default_path
 129  *
 130  *  Return the HOME directory path. Caller MUST NOT free(3) the return pointer.
 131  */
 132 char *config_get_default_path(void)
 133 {
 134         return getenv("HOME");
 135 }
 136
 137 /*
 138  *  config_destroy
 139  *
 140  *  Destroy directory config and file config.
 141  */
 142 void config_destroy(char *path)
 143 {
 144         int ret;
 145         char *config_path;
 146
 147         config_path = config_get_file_path(path);
 148         if (config_path == NULL) {
 149                 return;
 150         }
 151
 152         ret = remove(config_path);
 153         if (ret < 0) {
 154                 perror("remove config file");
 155         }
 156
 157         free(config_path);
 158 }
 159
 160 /*
 161  *  config_read_session_name
 162  *
 163  *  Return sesson name from the config file.
 164  */
 165 char *config_read_session_name(char *path)
 166 {
 167         int ret;
 168         FILE *fp;
 169         char var[NAME_MAX], *session_name;
 170
 171         fp = open_config(path, "r");
 172         if (fp == NULL) {
 173                 ERR("Can't find valid lttng config %s/.lttngrc", path);
 174                 goto error;
 175         }
 176
 177         session_name = malloc(NAME_MAX);
 178         while (!feof(fp)) {
 179                 if ((ret = fscanf(fp, "%[^'=']=%s\n", var, session_name)) != 2) {
 180                         if (ret == -1) {
 181                                 ERR("Missing session=NAME in config file.");
 182                                 goto error;
 183                         }
 184                         continue;
 185                 }
 186
 187                 if (strcmp(var, "session") == 0) {
 188                         goto found;
 189                 }
 190         }
 191
 192         fclose(fp);
 193
 194 error:
 195         return NULL;
 196
 197 found:
 198         fclose(fp);
 199         return session_name;
 200
 201 }
 202
 203 /*
 204  *  config_add_session_name
 205  *
 206  *  Write session name option to the config file.
 207  */
 208 int config_add_session_name(char *path, char *name)
 209 {
 210         int ret;
 211         char session_name[NAME_MAX];
 212
 213         ret = snprintf(session_name, NAME_MAX, "session=%s\n", name);
 214         if (ret < 0) {
 215                 goto error;
 216         }
 217         ret = write_config(path, ret, session_name);
 218 error:
 219         return ret;
 220 }
 221
 222 /*
 223  *  config_init
 224  *
 225  *  Init configuration directory and file.
 226  */
 227 int config_init(char *session_name)
 228 {
 229         int ret;
 230         char *path;
 231
 232         path = config_get_default_path();
 233         if (path == NULL) {
 234                 ret = -1;
 235                 goto error;
 236         }
 237
 238         /* Create default config file */
 239         ret = create_config_file(path);
 240         if (ret < 0) {
 241                 goto error;
 242         }
 243
 244         ret = config_add_session_name(path, session_name);
 245         if (ret < 0) {
 246                 goto error;
 247         }
 248
 249         DBG("Init config session in %s", path);
 250
 251 error:
 252         return ret;
 253 }