udev/lib/libudev.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <stdarg.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28
  29 #include "libudev.h"
  30 #include "libudev-private.h"
  31
  32 struct udev {
  33         int refcount;
  34         void (*log_fn)(struct udev *udev,
  35                        int priority, const char *file, int line, const char *fn,
  36                        const char *format, va_list args);
  37         void *userdata;
  38         char *sys_path;
  39         char *dev_path;
  40         char *rules_path;
  41         struct udev_list_node properties_list;
  42         int log_priority;
  43         int run;
  44 };
  45
  46 void udev_log(struct udev *udev,
  47               int priority, const char *file, int line, const char *fn,
  48               const char *format, ...)
  49 {
  50         va_list args;
  51
  52         if (priority > udev->log_priority)
  53                 return;
  54
  55         va_start(args, format);
  56         udev->log_fn(udev, priority, file, line, fn, format, args);
  57         va_end(args);
  58 }
  59
  60 static void log_stderr(struct udev *udev,
  61                        int priority, const char *file, int line, const char *fn,
  62                        const char *format, va_list args)
  63 {
  64         fprintf(stderr, "libudev: %s: ", fn);
  65         vfprintf(stderr, format, args);
  66 }
  67
  68 void *udev_get_userdata(struct udev *udev)
  69 {
  70         if (udev == NULL)
  71                 return NULL;
  72         return udev->userdata;
  73 }
  74
  75 void udev_set_userdata(struct udev *udev, void *userdata)
  76 {
  77         if (udev == NULL)
  78                 return;
  79         udev->userdata = userdata;
  80 }
  81
  82 /**
  83  * udev_new:
  84  *
  85  * Create udev library context.
  86  *
  87  * The initial refcount is 1, and needs to be decremented to
  88  * release the ressources of the udev library context.
  89  *
  90  * Returns: a new udev library context
  91  **/
  92 struct udev *udev_new(void)
  93 {
  94         struct udev *udev;
  95         const char *env;
  96         char *config_file;
  97         FILE *f;
  98
  99         udev = malloc(sizeof(struct udev));
 100         if (udev == NULL)
 101                 return NULL;
 102         memset(udev, 0x00, (sizeof(struct udev)));
 103         udev->refcount = 1;
 104         udev->log_fn = log_stderr;
 105         udev->log_priority = LOG_ERR;
 106         udev_list_init(&udev->properties_list);
 107         udev->run = 1;
 108         udev->dev_path = strdup(UDEV_PREFIX "/dev");
 109         udev->sys_path = strdup("/sys");
 110         config_file = strdup(SYSCONFDIR "/udev/udev.conf");
 111         if (udev->dev_path == NULL ||
 112             udev->sys_path == NULL ||
 113             config_file == NULL)
 114                 goto err;
 115
 116         /* settings by environment and config file */
 117         env = getenv("SYSFS_PATH");
 118         if (env != NULL) {
 119                 free(udev->sys_path);
 120                 udev->sys_path = strdup(env);
 121                 util_remove_trailing_chars(udev->sys_path, '/');
 122                 udev_add_property(udev, "SYSFS_PATH", udev->sys_path);
 123         }
 124
 125         env = getenv("UDEV_RUN");
 126         if (env != NULL && strcmp(env, "0") == 0)
 127                 udev->run = 0;
 128
 129         env = getenv("UDEV_CONFIG_FILE");
 130         if (env != NULL) {
 131                 free(config_file);
 132                 config_file = strdup(env);
 133                 util_remove_trailing_chars(config_file, '/');
 134         }
 135         if (config_file == NULL)
 136                 goto err;
 137         f = fopen(config_file, "r");
 138         if (f != NULL) {
 139                 char line[UTIL_LINE_SIZE];
 140                 int line_nr = 0;
 141
 142                 while (fgets(line, sizeof(line), f)) {
 143                         size_t len;
 144                         char *key;
 145                         char *val;
 146
 147                         line_nr++;
 148
 149                         /* find key */
 150                         key = line;
 151                         while (isspace(key[0]))
 152                                 key++;
 153
 154                         /* comment or empty line */
 155                         if (key[0] == '#' || key[0] == '\0')
 156                                 continue;
 157
 158                         /* split key/value */
 159                         val = strchr(key, '=');
 160                         if (val == NULL) {
 161                                 err(udev, "missing <key>=<value> in '%s'[%i], skip line\n", config_file, line_nr);
 162                                 continue;
 163                         }
 164                         val[0] = '\0';
 165                         val++;
 166
 167                         /* find value */
 168                         while (isspace(val[0]))
 169                                 val++;
 170
 171                         /* terminate key */
 172                         len = strlen(key);
 173                         if (len == 0)
 174                                 continue;
 175                         while (isspace(key[len-1]))
 176                                 len--;
 177                         key[len] = '\0';
 178
 179                         /* terminate value */
 180                         len = strlen(val);
 181                         if (len == 0)
 182                                 continue;
 183                         while (isspace(val[len-1]))
 184                                 len--;
 185                         val[len] = '\0';
 186
 187                         if (len == 0)
 188                                 continue;
 189
 190                         /* unquote */
 191                         if (val[0] == '"' || val[0] == '\'') {
 192                                 if (val[len-1] != val[0]) {
 193                                         err(udev, "inconsistent quoting in '%s'[%i], skip line\n", config_file, line_nr);
 194                                         continue;
 195                                 }
 196                                 val[len-1] = '\0';
 197                                 val++;
 198                         }
 199
 200                         if (strcasecmp(key, "udev_log") == 0) {
 201                                 udev->log_priority = util_log_priority(val);
 202                                 continue;
 203                         }
 204                         if (strcasecmp(key, "udev_root") == 0) {
 205                                 free(udev->dev_path);
 206                                 udev->dev_path = strdup(val);
 207                                 util_remove_trailing_chars(udev->dev_path, '/');
 208                                 continue;
 209                         }
 210                         if (strcasecmp(key, "udev_rules") == 0) {
 211                                 free(udev->rules_path);
 212                                 udev->rules_path = strdup(val);
 213                                 util_remove_trailing_chars(udev->rules_path, '/');
 214                                 continue;
 215                         }
 216                 }
 217                 fclose(f);
 218         }
 219
 220         env = getenv("UDEV_ROOT");
 221         if (env != NULL) {
 222                 free(udev->dev_path);
 223                 udev->dev_path = strdup(env);
 224                 util_remove_trailing_chars(udev->dev_path, '/');
 225                 udev_add_property(udev, "UDEV_ROOT", udev->dev_path);
 226         }
 227
 228         env = getenv("UDEV_LOG");
 229         if (env != NULL)
 230                 udev_set_log_priority(udev, util_log_priority(env));
 231
 232         if (udev->dev_path == NULL || udev->sys_path == NULL)
 233                 goto err;
 234         info(udev, "context %p created\n", udev);
 235         info(udev, "log_priority=%d\n", udev->log_priority);
 236         info(udev, "config_file='%s'\n", config_file);
 237         info(udev, "dev_path='%s'\n", udev->dev_path);
 238         info(udev, "sys_path='%s'\n", udev->sys_path);
 239         if (udev->rules_path != NULL)
 240                 info(udev, "rules_path='%s'\n", udev->rules_path);
 241         free(config_file);
 242         return udev;
 243 err:
 244         free(config_file);
 245         err(udev, "context creation failed\n");
 246         udev_unref(udev);
 247         return NULL;
 248 }
 249
 250 /**
 251  * udev_ref:
 252  * @udev: udev library context
 253  *
 254  * Take a reference of the udev library context.
 255  *
 256  * Returns: the passed udev library context
 257  **/
 258 struct udev *udev_ref(struct udev *udev)
 259 {
 260         if (udev == NULL)
 261                 return NULL;
 262         udev->refcount++;
 263         return udev;
 264 }
 265
 266 /**
 267  * udev_unref:
 268  * @udev: udev library context
 269  *
 270  * Drop a reference of the udev library context. If the refcount
 271  * reaches zero, the ressources of the context will be released.
 272  *
 273  **/
 274 void udev_unref(struct udev *udev)
 275 {
 276         if (udev == NULL)
 277                 return;
 278         udev->refcount--;
 279         if (udev->refcount > 0)
 280                 return;
 281         udev_list_cleanup(udev, &udev->properties_list);
 282         free(udev->dev_path);
 283         free(udev->sys_path);
 284         free(udev->rules_path);
 285         info(udev, "context %p released\n", udev);
 286         free(udev);
 287 }
 288
 289 /**
 290  * udev_set_log_fn:
 291  * @udev: udev library context
 292  * @log_fn: function to be called for logging messages
 293  *
 294  * The built-in logging, which writes to stderr, it can be
 295  * overridden by a custom function, to plug log messages
 296  * into the users logging functionality.
 297  *
 298  **/
 299 void udev_set_log_fn(struct udev *udev,
 300                      void (*log_fn)(struct udev *udev,
 301                                     int priority, const char *file, int line, const char *fn,
 302                                     const char *format, va_list args))
 303 {
 304         udev->log_fn = log_fn;
 305         info(udev, "custom logging function %p registered\n", udev);
 306 }
 307
 308 int udev_get_log_priority(struct udev *udev)
 309 {
 310         return udev->log_priority;
 311 }
 312
 313 void udev_set_log_priority(struct udev *udev, int priority)
 314 {
 315         char num[32];
 316
 317         udev->log_priority = priority;
 318         snprintf(num, sizeof(num), "%u", udev->log_priority);
 319         udev_add_property(udev, "UDEV_LOG", num);
 320 }
 321
 322 const char *udev_get_rules_path(struct udev *udev)
 323 {
 324         return udev->rules_path;
 325 }
 326
 327 int udev_get_run(struct udev *udev)
 328 {
 329         return udev->run;
 330 }
 331
 332 /**
 333  * udev_get_sys_path:
 334  * @udev: udev library context
 335  *
 336  * Retrieve the sysfs mount point. The default is "/sys". For
 337  * testing purposes, it can be overridden with the environment
 338  * variable SYSFS_PATH.
 339  *
 340  * Returns: the sys mount point
 341  **/
 342 const char *udev_get_sys_path(struct udev *udev)
 343 {
 344         if (udev == NULL)
 345                 return NULL;
 346         return udev->sys_path;
 347 }
 348
 349 /**
 350  * udev_get_dev_path:
 351  * @udev: udev library context
 352  *
 353  * Retrieve the device directory path. The default value is "/dev",
 354  * the actual value may be overridden in the udev configuration
 355  * file.
 356  *
 357  * Returns: the device directory path
 358  **/
 359 const char *udev_get_dev_path(struct udev *udev)
 360 {
 361         if (udev == NULL)
 362                 return NULL;
 363         return udev->dev_path;
 364 }
 365
 366 struct udev_list_entry *udev_add_property(struct udev *udev, const char *key, const char *value)
 367 {
 368         if (value == NULL) {
 369                 struct udev_list_entry *list_entry;
 370
 371                 list_entry = udev_get_properties_list_entry(udev);
 372                 list_entry = udev_list_entry_get_by_name(list_entry, key);
 373                 if (list_entry != NULL)
 374                         udev_list_entry_remove(list_entry);
 375                 return NULL;
 376         }
 377         return udev_list_entry_add(udev, &udev->properties_list, key, value, 1, 0);
 378 }
 379
 380 struct udev_list_entry *udev_get_properties_list_entry(struct udev *udev)
 381 {
 382         return udev_list_get_entry(&udev->properties_list);
 383 }