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  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   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  *  get_config_file_path
  33  *
  34  *  Return the path with '/CONFIG_FILENAME' added to it.
  35  */
  36 static char *get_config_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 = get_config_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  *  create_config_dir
 102  *
 103  *  Create the empty config dir.
 104  */
 105 static int create_config_dir(char *path)
 106 {
 107         int ret;
 108
 109         /* Create session directory .lttng */
 110         ret = mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP);
 111         if (ret < 0) {
 112                 if (errno == EEXIST) {
 113                         ERR("Session already exist at %s", path);
 114                 } else  {
 115                         perror("mkdir config");
 116                         ERR("Couldn't init config directory at %s", path);
 117                 }
 118                 ret = -errno;
 119                 goto error;
 120         }
 121
 122 error:
 123         return ret;
 124 }
 125
 126 /*
 127  *  write_config
 128  *
 129  *  Append data to the config file in file_path
 130  */
 131 static void write_config(char *file_path, size_t size, char *data)
 132 {
 133         FILE *fp;
 134
 135         fp = open_config(file_path, "a");
 136         if (fp == NULL) {
 137                 goto error;
 138         }
 139
 140         /* Write session name into config file */
 141         fwrite(data, size, 1, fp);
 142         fclose(fp);
 143
 144 error:
 145         return;
 146 }
 147
 148 /*
 149  *  config_get_default_path
 150  *
 151  *  Return the HOME directory path. The output is dup so the user MUST
 152  *  free(3) the returned string.
 153  */
 154 char *config_get_default_path(void)
 155 {
 156         return strdup(getenv("HOME"));
 157 }
 158
 159 /*
 160  *  config_destroy
 161  *
 162  *  Destroy directory config and file config.
 163  */
 164 void config_destroy(char *path)
 165 {
 166         int ret;
 167         char *config_path;
 168
 169         config_path = get_config_file_path(path);
 170
 171         ret = remove(config_path);
 172         if (ret < 0) {
 173                 perror("remove config file");
 174         }
 175
 176         ret = rmdir(path);
 177         if (ret < 0) {
 178                 perror("rmdir config dir");
 179         }
 180
 181         free(config_path);
 182 }
 183
 184 /*
 185  *  config_read_session_name
 186  *
 187  *  Return sesson name from the config file.
 188  */
 189 char *config_read_session_name(char *path)
 190 {
 191         int ret;
 192         FILE *fp;
 193         char var[NAME_MAX], *session_name;
 194
 195         fp = open_config(path, "r");
 196         if (fp == NULL) {
 197                 ERR("Can't find valid lttng config in %s", path);
 198                 goto error;
 199         }
 200
 201         session_name = malloc(NAME_MAX);
 202         while (!feof(fp)) {
 203                 if ((ret = fscanf(fp, "%[^'=']=%s\n", var, session_name)) != 2) {
 204                         if (ret == -1) {
 205                                 ERR("Missing session=NAME in config file.");
 206                                 goto error;
 207                         }
 208                         continue;
 209                 }
 210
 211                 if (strcmp(var, "session") == 0) {
 212                         goto found;
 213                 }
 214         }
 215
 216         fclose(fp);
 217
 218 error:
 219         return NULL;
 220
 221 found:
 222         fclose(fp);
 223         return session_name;
 224
 225 }
 226
 227 /*
 228  *  config_add_session_name
 229  *
 230  *  Write session name option to the config file.
 231  */
 232 int config_add_session_name(char *path, char *name)
 233 {
 234         int ret;
 235         char session_name[NAME_MAX];
 236
 237         ret = snprintf(session_name, NAME_MAX, "session=%s\n", name);
 238         if (ret < 0) {
 239                 goto error;
 240         }
 241
 242         write_config(path, ret, session_name);
 243         ret = 0;
 244
 245 error:
 246         return ret;
 247 }
 248
 249 /*
 250  *  config_generate_dir_path
 251  *
 252  *  Return allocated path string to path/CONFIG_DIRNAME.
 253  */
 254 char *config_generate_dir_path(char *path)
 255 {
 256         int ret;
 257         char *new_path;
 258
 259         ret = asprintf(&new_path, "%s/%s", path, CONFIG_DIRNAME);
 260         if (ret < 0) {
 261                 perror("config path problem");
 262                 goto error;
 263         }
 264
 265 error:
 266         return new_path;
 267 }
 268
 269 /*
 270  *  config_init
 271  *
 272  *  Init configuration directory and file.
 273  */
 274 int config_init(char *path)
 275 {
 276         int ret;
 277
 278         /* Create config directory (.lttng) */
 279         ret = create_config_dir(path);
 280         if (ret < 0) {
 281                 goto error;
 282         }
 283
 284         /* Create default config file */
 285         ret = create_config_file(path);
 286         if (ret < 0) {
 287                 goto error;
 288         }
 289
 290         DBG("Init config session in %s", path);
 291
 292 error:
 293         return ret;
 294 }