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 resources 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 = calloc(1, sizeof(struct udev));
 100         if (udev == NULL)
 101                 return NULL;
 102         udev->refcount = 1;
 103         udev->log_fn = log_stderr;
 104         udev->log_priority = LOG_ERR;
 105         udev_list_init(&udev->properties_list);
 106         udev->run = 1;
 107         udev->dev_path = strdup(UDEV_PREFIX "/dev");
 108         udev->sys_path = strdup("/sys");
 109         config_file = strdup(SYSCONFDIR "/udev/udev.conf");
 110         if (udev->dev_path == NULL ||
 111             udev->sys_path == NULL ||
 112             config_file == NULL)
 113                 goto err;
 114
 115         /* settings by environment and config file */
 116         env = getenv("SYSFS_PATH");
 117         if (env != NULL) {
 118                 free(udev->sys_path);
 119                 udev->sys_path = strdup(env);
 120                 util_remove_trailing_chars(udev->sys_path, '/');
 121                 udev_add_property(udev, "SYSFS_PATH", udev->sys_path);
 122         }
 123
 124         env = getenv("UDEV_RUN");
 125         if (env != NULL && strcmp(env, "0") == 0)
 126                 udev->run = 0;
 127
 128         env = getenv("UDEV_CONFIG_FILE");
 129         if (env != NULL) {
 130                 free(config_file);
 131                 config_file = strdup(env);
 132                 util_remove_trailing_chars(config_file, '/');
 133         }
 134         if (config_file == NULL)
 135                 goto err;
 136         f = fopen(config_file, "r");
 137         if (f != NULL) {
 138                 char line[UTIL_LINE_SIZE];
 139                 int line_nr = 0;
 140
 141                 while (fgets(line, sizeof(line), f)) {
 142                         size_t len;
 143                         char *key;
 144                         char *val;
 145
 146                         line_nr++;
 147
 148                         /* find key */
 149                         key = line;
 150                         while (isspace(key[0]))
 151                                 key++;
 152
 153                         /* comment or empty line */
 154                         if (key[0] == '#' || key[0] == '\0')
 155                                 continue;
 156
 157                         /* split key/value */
 158                         val = strchr(key, '=');
 159                         if (val == NULL) {
 160                                 err(udev, "missing <key>=<value> in '%s'[%i], skip line\n", config_file, line_nr);
 161                                 continue;
 162                         }
 163                         val[0] = '\0';
 164                         val++;
 165
 166                         /* find value */
 167                         while (isspace(val[0]))
 168                                 val++;
 169
 170                         /* terminate key */
 171                         len = strlen(key);
 172                         if (len == 0)
 173                                 continue;
 174                         while (isspace(key[len-1]))
 175                                 len--;
 176                         key[len] = '\0';
 177
 178                         /* terminate value */
 179                         len = strlen(val);
 180                         if (len == 0)
 181                                 continue;
 182                         while (isspace(val[len-1]))
 183                                 len--;
 184                         val[len] = '\0';
 185
 186                         if (len == 0)
 187                                 continue;
 188
 189                         /* unquote */
 190                         if (val[0] == '"' || val[0] == '\'') {
 191                                 if (val[len-1] != val[0]) {
 192                                         err(udev, "inconsistent quoting in '%s'[%i], skip line\n", config_file, line_nr);
 193                                         continue;
 194                                 }
 195                                 val[len-1] = '\0';
 196                                 val++;
 197                         }
 198
 199                         if (strcasecmp(key, "udev_log") == 0) {
 200                                 udev_set_log_priority(udev, util_log_priority(val));
 201                                 continue;
 202                         }
 203                         if (strcasecmp(key, "udev_root") == 0) {
 204                                 free(udev->dev_path);
 205                                 udev->dev_path = strdup(val);
 206                                 util_remove_trailing_chars(udev->dev_path, '/');
 207                                 continue;
 208                         }
 209                         if (strcasecmp(key, "udev_rules") == 0) {
 210                                 free(udev->rules_path);
 211                                 udev->rules_path = strdup(val);
 212                                 util_remove_trailing_chars(udev->rules_path, '/');
 213                                 continue;
 214                         }
 215                 }
 216                 fclose(f);
 217         }
 218
 219         env = getenv("UDEV_ROOT");
 220         if (env != NULL) {
 221                 free(udev->dev_path);
 222                 udev->dev_path = strdup(env);
 223                 util_remove_trailing_chars(udev->dev_path, '/');
 224                 udev_add_property(udev, "UDEV_ROOT", udev->dev_path);
 225         }
 226
 227         env = getenv("UDEV_LOG");
 228         if (env != NULL)
 229                 udev_set_log_priority(udev, util_log_priority(env));
 230
 231         if (udev->dev_path == NULL || udev->sys_path == NULL)
 232                 goto err;
 233         dbg(udev, "context %p created\n", udev);
 234         dbg(udev, "log_priority=%d\n", udev->log_priority);
 235         dbg(udev, "config_file='%s'\n", config_file);
 236         dbg(udev, "dev_path='%s'\n", udev->dev_path);
 237         dbg(udev, "sys_path='%s'\n", udev->sys_path);
 238         if (udev->rules_path != NULL)
 239                 dbg(udev, "rules_path='%s'\n", udev->rules_path);
 240         free(config_file);
 241         return udev;
 242 err:
 243         free(config_file);
 244         err(udev, "context creation failed\n");
 245         udev_unref(udev);
 246         return NULL;
 247 }
 248
 249 /**
 250  * udev_ref:
 251  * @udev: udev library context
 252  *
 253  * Take a reference of the udev library context.
 254  *
 255  * Returns: the passed udev library context
 256  **/
 257 struct udev *udev_ref(struct udev *udev)
 258 {
 259         if (udev == NULL)
 260                 return NULL;
 261         udev->refcount++;
 262         return udev;
 263 }
 264
 265 /**
 266  * udev_unref:
 267  * @udev: udev library context
 268  *
 269  * Drop a reference of the udev library context. If the refcount
 270  * reaches zero, the resources of the context will be released.
 271  *
 272  **/
 273 void udev_unref(struct udev *udev)
 274 {
 275         if (udev == NULL)
 276                 return;
 277         udev->refcount--;
 278         if (udev->refcount > 0)
 279                 return;
 280         udev_list_cleanup_entries(udev, &udev->properties_list);
 281         free(udev->dev_path);
 282         free(udev->sys_path);
 283         free(udev->rules_path);
 284         dbg(udev, "context %p released\n", udev);
 285         free(udev);
 286 }
 287
 288 /**
 289  * udev_set_log_fn:
 290  * @udev: udev library context
 291  * @log_fn: function to be called for logging messages
 292  *
 293  * The built-in logging writes to stderr. It can be
 294  * overridden by a custom function, to plug log messages
 295  * into the users' logging functionality.
 296  *
 297  **/
 298 void udev_set_log_fn(struct udev *udev,
 299                      void (*log_fn)(struct udev *udev,
 300                                     int priority, const char *file, int line, const char *fn,
 301                                     const char *format, va_list args))
 302 {
 303         udev->log_fn = log_fn;
 304         info(udev, "custom logging function %p registered\n", udev);
 305 }
 306
 307 int udev_get_log_priority(struct udev *udev)
 308 {
 309         return udev->log_priority;
 310 }
 311
 312 void udev_set_log_priority(struct udev *udev, int priority)
 313 {
 314         char num[32];
 315
 316         udev->log_priority = priority;
 317         snprintf(num, sizeof(num), "%u", udev->log_priority);
 318         udev_add_property(udev, "UDEV_LOG", num);
 319 }
 320
 321 const char *udev_get_rules_path(struct udev *udev)
 322 {
 323         return udev->rules_path;
 324 }
 325
 326 int udev_get_run(struct udev *udev)
 327 {
 328         return udev->run;
 329 }
 330
 331 /**
 332  * udev_get_sys_path:
 333  * @udev: udev library context
 334  *
 335  * Retrieve the sysfs mount point. The default is "/sys". For
 336  * testing purposes, it can be overridden with the environment
 337  * variable SYSFS_PATH.
 338  *
 339  * Returns: the sys mount point
 340  **/
 341 const char *udev_get_sys_path(struct udev *udev)
 342 {
 343         if (udev == NULL)
 344                 return NULL;
 345         return udev->sys_path;
 346 }
 347
 348 /**
 349  * udev_get_dev_path:
 350  * @udev: udev library context
 351  *
 352  * Retrieve the device directory path. The default value is "/dev",
 353  * the actual value may be overridden in the udev configuration
 354  * file.
 355  *
 356  * Returns: the device directory path
 357  **/
 358 const char *udev_get_dev_path(struct udev *udev)
 359 {
 360         if (udev == NULL)
 361                 return NULL;
 362         return udev->dev_path;
 363 }
 364
 365 struct udev_list_entry *udev_add_property(struct udev *udev, const char *key, const char *value)
 366 {
 367         if (value == NULL) {
 368                 struct udev_list_entry *list_entry;
 369
 370                 list_entry = udev_get_properties_list_entry(udev);
 371                 list_entry = udev_list_entry_get_by_name(list_entry, key);
 372                 if (list_entry != NULL)
 373                         udev_list_entry_delete(list_entry);
 374                 return NULL;
 375         }
 376         return udev_list_entry_add(udev, &udev->properties_list, key, value, 1, 0);
 377 }
 378
 379 struct udev_list_entry *udev_get_properties_list_entry(struct udev *udev)
 380 {
 381         return udev_list_get_entry(&udev->properties_list);
 382 }