src/libudev/libudev.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2008-2014 Kay Sievers <kay@vrfy.org>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <ctype.h>
  21 #include <stdarg.h>
  22 #include <stddef.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include "libudev.h"
  28
  29 #include "libudev-private.h"
  30 #include "missing.h"
  31 #include "string-util.h"
  32
  33 /**
  34  * SECTION:libudev
  35  * @short_description: libudev context
  36  *
  37  * The context contains the default values read from the udev config file,
  38  * and is passed to all library operations.
  39  */
  40
  41 /**
  42  * udev:
  43  *
  44  * Opaque object representing the library context.
  45  */
  46 struct udev {
  47         int refcount;
  48         void (*log_fn)(struct udev *udev,
  49                        int priority, const char *file, int line, const char *fn,
  50                        const char *format, va_list args);
  51         void *userdata;
  52 };
  53
  54 /**
  55  * udev_get_userdata:
  56  * @udev: udev library context
  57  *
  58  * Retrieve stored data pointer from library context. This might be useful
  59  * to access from callbacks.
  60  *
  61  * Returns: stored userdata
  62  **/
  63 _public_ void *udev_get_userdata(struct udev *udev) {
  64         if (udev == NULL)
  65                 return NULL;
  66         return udev->userdata;
  67 }
  68
  69 /**
  70  * udev_set_userdata:
  71  * @udev: udev library context
  72  * @userdata: data pointer
  73  *
  74  * Store custom @userdata in the library context.
  75  **/
  76 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  77         if (udev == NULL)
  78                 return;
  79         udev->userdata = userdata;
  80 }
  81
  82 /**
  83  * udev_new:
  84  *
  85  * Create udev library context. This reads the udev configuration
  86  * file, and fills in the default values.
  87  *
  88  * The initial refcount is 1, and needs to be decremented to
  89  * release the resources of the udev library context.
  90  *
  91  * Returns: a new udev library context
  92  **/
  93 _public_ struct udev *udev_new(void) {
  94         struct udev *udev;
  95         _cleanup_fclose_ FILE *f = NULL;
  96
  97         udev = new0(struct udev, 1);
  98         if (udev == NULL)
  99                 return NULL;
 100         udev->refcount = 1;
 101
 102         f = fopen("/etc/udev/udev.conf", "re");
 103         if (f != NULL) {
 104                 char line[UTIL_LINE_SIZE];
 105                 unsigned line_nr = 0;
 106
 107                 while (fgets(line, sizeof(line), f)) {
 108                         size_t len;
 109                         char *key;
 110                         char *val;
 111
 112                         line_nr++;
 113
 114                         /* find key */
 115                         key = line;
 116                         while (isspace(key[0]))
 117                                 key++;
 118
 119                         /* comment or empty line */
 120                         if (key[0] == '#' || key[0] == '\0')
 121                                 continue;
 122
 123                         /* split key/value */
 124                         val = strchr(key, '=');
 125                         if (val == NULL) {
 126                                 log_debug("/etc/udev/udev.conf:%u: missing assignment,  skipping line.", line_nr);
 127                                 continue;
 128                         }
 129                         val[0] = '\0';
 130                         val++;
 131
 132                         /* find value */
 133                         while (isspace(val[0]))
 134                                 val++;
 135
 136                         /* terminate key */
 137                         len = strlen(key);
 138                         if (len == 0)
 139                                 continue;
 140                         while (isspace(key[len-1]))
 141                                 len--;
 142                         key[len] = '\0';
 143
 144                         /* terminate value */
 145                         len = strlen(val);
 146                         if (len == 0)
 147                                 continue;
 148                         while (isspace(val[len-1]))
 149                                 len--;
 150                         val[len] = '\0';
 151
 152                         if (len == 0)
 153                                 continue;
 154
 155                         /* unquote */
 156                         if (val[0] == '"' || val[0] == '\'') {
 157                                 if (val[len-1] != val[0]) {
 158                                         log_debug("/etc/udev/udev.conf:%u: inconsistent quoting, skipping line.", line_nr);
 159                                         continue;
 160                                 }
 161                                 val[len-1] = '\0';
 162                                 val++;
 163                         }
 164
 165                         if (streq(key, "udev_log")) {
 166                                 int prio;
 167
 168                                 prio = util_log_priority(val);
 169                                 if (prio < 0)
 170                                         log_debug("/etc/udev/udev.conf:%u: invalid log level '%s', ignoring.", line_nr, val);
 171                                 else
 172                                         log_set_max_level(prio);
 173                                 continue;
 174                         }
 175                 }
 176         }
 177
 178         return udev;
 179 }
 180
 181 /**
 182  * udev_ref:
 183  * @udev: udev library context
 184  *
 185  * Take a reference of the udev library context.
 186  *
 187  * Returns: the passed udev library context
 188  **/
 189 _public_ struct udev *udev_ref(struct udev *udev) {
 190         if (udev == NULL)
 191                 return NULL;
 192         udev->refcount++;
 193         return udev;
 194 }
 195
 196 /**
 197  * udev_unref:
 198  * @udev: udev library context
 199  *
 200  * Drop a reference of the udev library context. If the refcount
 201  * reaches zero, the resources of the context will be released.
 202  *
 203  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 204  **/
 205 _public_ struct udev *udev_unref(struct udev *udev) {
 206         if (udev == NULL)
 207                 return NULL;
 208         udev->refcount--;
 209         if (udev->refcount > 0)
 210                 return udev;
 211         free(udev);
 212         return NULL;
 213 }
 214
 215 /**
 216  * udev_set_log_fn:
 217  * @udev: udev library context
 218  * @log_fn: function to be called for log messages
 219  *
 220  * This function is deprecated.
 221  *
 222  **/
 223 _public_ void udev_set_log_fn(struct udev *udev,
 224                      void (*log_fn)(struct udev *udev,
 225                                     int priority, const char *file, int line, const char *fn,
 226                                     const char *format, va_list args)) {
 227         return;
 228 }
 229
 230 /**
 231  * udev_get_log_priority:
 232  * @udev: udev library context
 233  *
 234  * This function is deprecated.
 235  *
 236  **/
 237 _public_ int udev_get_log_priority(struct udev *udev) {
 238         return log_get_max_level();
 239 }
 240
 241 /**
 242  * udev_set_log_priority:
 243  * @udev: udev library context
 244  * @priority: the new log priority
 245  *
 246  * This function is deprecated.
 247  *
 248  **/
 249 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 250         log_set_max_level(priority);
 251 }