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 library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <stddef.h>
  15 #include <stdarg.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <string.h>
  19 #include <ctype.h>
  20
  21 #include "libudev.h"
  22 #include "libudev-private.h"
  23
  24 struct udev {
  25         int refcount;
  26         void (*log_fn)(struct udev *udev,
  27                        int priority, const char *file, int line, const char *fn,
  28                        const char *format, va_list args);
  29         void *userdata;
  30         char *sys_path;
  31         char *dev_path;
  32         char *rules_path;
  33         struct udev_list_node properties_list;
  34         int log_priority;
  35         int run;
  36 };
  37
  38 void udev_log(struct udev *udev,
  39               int priority, const char *file, int line, const char *fn,
  40               const char *format, ...)
  41 {
  42         va_list args;
  43
  44         if (priority > udev->log_priority)
  45                 return;
  46
  47         va_start(args, format);
  48         udev->log_fn(udev, priority, file, line, fn, format, args);
  49         va_end(args);
  50 }
  51
  52 static void log_stderr(struct udev *udev,
  53                        int priority, const char *file, int line, const char *fn,
  54                        const char *format, va_list args)
  55 {
  56         fprintf(stderr, "libudev: %s: ", fn);
  57         vfprintf(stderr, format, args);
  58 }
  59
  60 void *udev_get_userdata(struct udev *udev)
  61 {
  62         if (udev == NULL)
  63                 return NULL;
  64         return udev->userdata;
  65 }
  66
  67 void udev_set_userdata(struct udev *udev, void *userdata)
  68 {
  69         if (udev == NULL)
  70                 return;
  71         udev->userdata = userdata;
  72 }
  73
  74 /**
  75  * udev_new:
  76  *
  77  * Create udev library context.
  78  *
  79  * The initial refcount is 1, and needs to be decremented to
  80  * release the resources of the udev library context.
  81  *
  82  * Returns: a new udev library context
  83  **/
  84 struct udev *udev_new(void)
  85 {
  86         struct udev *udev;
  87         const char *env;
  88         char *config_file;
  89         FILE *f;
  90
  91         udev = calloc(1, sizeof(struct udev));
  92         if (udev == NULL)
  93                 return NULL;
  94         udev->refcount = 1;
  95         udev->log_fn = log_stderr;
  96         udev->log_priority = LOG_ERR;
  97         udev_list_init(&udev->properties_list);
  98         udev->run = 1;
  99         udev->dev_path = strdup(UDEV_PREFIX "/dev");
 100         udev->sys_path = strdup("/sys");
 101         config_file = strdup(SYSCONFDIR "/udev/udev.conf");
 102         if (udev->dev_path == NULL ||
 103             udev->sys_path == NULL ||
 104             config_file == NULL)
 105                 goto err;
 106
 107         /* settings by environment and config file */
 108         env = getenv("SYSFS_PATH");
 109         if (env != NULL) {
 110                 free(udev->sys_path);
 111                 udev->sys_path = strdup(env);
 112                 util_remove_trailing_chars(udev->sys_path, '/');
 113                 udev_add_property(udev, "SYSFS_PATH", udev->sys_path);
 114         }
 115
 116         env = getenv("UDEV_RUN");
 117         if (env != NULL && strcmp(env, "0") == 0)
 118                 udev->run = 0;
 119
 120         env = getenv("UDEV_CONFIG_FILE");
 121         if (env != NULL) {
 122                 free(config_file);
 123                 config_file = strdup(env);
 124                 util_remove_trailing_chars(config_file, '/');
 125         }
 126         if (config_file == NULL)
 127                 goto err;
 128         f = fopen(config_file, "r");
 129         if (f != NULL) {
 130                 char line[UTIL_LINE_SIZE];
 131                 int line_nr = 0;
 132
 133                 while (fgets(line, sizeof(line), f)) {
 134                         size_t len;
 135                         char *key;
 136                         char *val;
 137
 138                         line_nr++;
 139
 140                         /* find key */
 141                         key = line;
 142                         while (isspace(key[0]))
 143                                 key++;
 144
 145                         /* comment or empty line */
 146                         if (key[0] == '#' || key[0] == '\0')
 147                                 continue;
 148
 149                         /* split key/value */
 150                         val = strchr(key, '=');
 151                         if (val == NULL) {
 152                                 err(udev, "missing <key>=<value> in '%s'[%i], skip line\n", config_file, line_nr);
 153                                 continue;
 154                         }
 155                         val[0] = '\0';
 156                         val++;
 157
 158                         /* find value */
 159                         while (isspace(val[0]))
 160                                 val++;
 161
 162                         /* terminate key */
 163                         len = strlen(key);
 164                         if (len == 0)
 165                                 continue;
 166                         while (isspace(key[len-1]))
 167                                 len--;
 168                         key[len] = '\0';
 169
 170                         /* terminate value */
 171                         len = strlen(val);
 172                         if (len == 0)
 173                                 continue;
 174                         while (isspace(val[len-1]))
 175                                 len--;
 176                         val[len] = '\0';
 177
 178                         if (len == 0)
 179                                 continue;
 180
 181                         /* unquote */
 182                         if (val[0] == '"' || val[0] == '\'') {
 183                                 if (val[len-1] != val[0]) {
 184                                         err(udev, "inconsistent quoting in '%s'[%i], skip line\n", config_file, line_nr);
 185                                         continue;
 186                                 }
 187                                 val[len-1] = '\0';
 188                                 val++;
 189                         }
 190
 191                         if (strcasecmp(key, "udev_log") == 0) {
 192                                 udev_set_log_priority(udev, util_log_priority(val));
 193                                 continue;
 194                         }
 195                         if (strcasecmp(key, "udev_root") == 0) {
 196                                 free(udev->dev_path);
 197                                 udev->dev_path = strdup(val);
 198                                 util_remove_trailing_chars(udev->dev_path, '/');
 199                                 continue;
 200                         }
 201                         if (strcasecmp(key, "udev_rules") == 0) {
 202                                 free(udev->rules_path);
 203                                 udev->rules_path = strdup(val);
 204                                 util_remove_trailing_chars(udev->rules_path, '/');
 205                                 continue;
 206                         }
 207                 }
 208                 fclose(f);
 209         }
 210
 211         env = getenv("UDEV_ROOT");
 212         if (env != NULL) {
 213                 free(udev->dev_path);
 214                 udev->dev_path = strdup(env);
 215                 util_remove_trailing_chars(udev->dev_path, '/');
 216                 udev_add_property(udev, "UDEV_ROOT", udev->dev_path);
 217         }
 218
 219         env = getenv("UDEV_LOG");
 220         if (env != NULL)
 221                 udev_set_log_priority(udev, util_log_priority(env));
 222
 223         if (udev->dev_path == NULL || udev->sys_path == NULL)
 224                 goto err;
 225         dbg(udev, "context %p created\n", udev);
 226         dbg(udev, "log_priority=%d\n", udev->log_priority);
 227         dbg(udev, "config_file='%s'\n", config_file);
 228         dbg(udev, "dev_path='%s'\n", udev->dev_path);
 229         dbg(udev, "sys_path='%s'\n", udev->sys_path);
 230         if (udev->rules_path != NULL)
 231                 dbg(udev, "rules_path='%s'\n", udev->rules_path);
 232         free(config_file);
 233         return udev;
 234 err:
 235         free(config_file);
 236         err(udev, "context creation failed\n");
 237         udev_unref(udev);
 238         return NULL;
 239 }
 240
 241 /**
 242  * udev_ref:
 243  * @udev: udev library context
 244  *
 245  * Take a reference of the udev library context.
 246  *
 247  * Returns: the passed udev library context
 248  **/
 249 struct udev *udev_ref(struct udev *udev)
 250 {
 251         if (udev == NULL)
 252                 return NULL;
 253         udev->refcount++;
 254         return udev;
 255 }
 256
 257 /**
 258  * udev_unref:
 259  * @udev: udev library context
 260  *
 261  * Drop a reference of the udev library context. If the refcount
 262  * reaches zero, the resources of the context will be released.
 263  *
 264  **/
 265 void udev_unref(struct udev *udev)
 266 {
 267         if (udev == NULL)
 268                 return;
 269         udev->refcount--;
 270         if (udev->refcount > 0)
 271                 return;
 272         udev_list_cleanup_entries(udev, &udev->properties_list);
 273         free(udev->dev_path);
 274         free(udev->sys_path);
 275         free(udev->rules_path);
 276         dbg(udev, "context %p released\n", udev);
 277         free(udev);
 278 }
 279
 280 /**
 281  * udev_set_log_fn:
 282  * @udev: udev library context
 283  * @log_fn: function to be called for logging messages
 284  *
 285  * The built-in logging writes to stderr. It can be
 286  * overridden by a custom function, to plug log messages
 287  * into the users' logging functionality.
 288  *
 289  **/
 290 void udev_set_log_fn(struct udev *udev,
 291                      void (*log_fn)(struct udev *udev,
 292                                     int priority, const char *file, int line, const char *fn,
 293                                     const char *format, va_list args))
 294 {
 295         udev->log_fn = log_fn;
 296         info(udev, "custom logging function %p registered\n", udev);
 297 }
 298
 299 int udev_get_log_priority(struct udev *udev)
 300 {
 301         return udev->log_priority;
 302 }
 303
 304 void udev_set_log_priority(struct udev *udev, int priority)
 305 {
 306         char num[32];
 307
 308         udev->log_priority = priority;
 309         snprintf(num, sizeof(num), "%u", udev->log_priority);
 310         udev_add_property(udev, "UDEV_LOG", num);
 311 }
 312
 313 const char *udev_get_rules_path(struct udev *udev)
 314 {
 315         return udev->rules_path;
 316 }
 317
 318 int udev_get_run(struct udev *udev)
 319 {
 320         return udev->run;
 321 }
 322
 323 /**
 324  * udev_get_sys_path:
 325  * @udev: udev library context
 326  *
 327  * Retrieve the sysfs mount point. The default is "/sys". For
 328  * testing purposes, it can be overridden with the environment
 329  * variable SYSFS_PATH.
 330  *
 331  * Returns: the sys mount point
 332  **/
 333 const char *udev_get_sys_path(struct udev *udev)
 334 {
 335         if (udev == NULL)
 336                 return NULL;
 337         return udev->sys_path;
 338 }
 339
 340 /**
 341  * udev_get_dev_path:
 342  * @udev: udev library context
 343  *
 344  * Retrieve the device directory path. The default value is "/dev",
 345  * the actual value may be overridden in the udev configuration
 346  * file.
 347  *
 348  * Returns: the device directory path
 349  **/
 350 const char *udev_get_dev_path(struct udev *udev)
 351 {
 352         if (udev == NULL)
 353                 return NULL;
 354         return udev->dev_path;
 355 }
 356
 357 struct udev_list_entry *udev_add_property(struct udev *udev, const char *key, const char *value)
 358 {
 359         if (value == NULL) {
 360                 struct udev_list_entry *list_entry;
 361
 362                 list_entry = udev_get_properties_list_entry(udev);
 363                 list_entry = udev_list_entry_get_by_name(list_entry, key);
 364                 if (list_entry != NULL)
 365                         udev_list_entry_delete(list_entry);
 366                 return NULL;
 367         }
 368         return udev_list_entry_add(udev, &udev->properties_list, key, value, 1, 0);
 369 }
 370
 371 struct udev_list_entry *udev_get_properties_list_entry(struct udev *udev)
 372 {
 373         return udev_list_get_entry(&udev->properties_list);
 374 }