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 <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 #include <time.h>
  29
  30 #include "libudev.h"
  31 #include "libudev-private.h"
  32 #include "missing.h"
  33
  34 /**
  35  * SECTION:libudev
  36  * @short_description: libudev context
  37  *
  38  * The context contains the default values read from the udev config file,
  39  * and is passed to all library operations.
  40  */
  41
  42 /**
  43  * udev:
  44  *
  45  * Opaque object representing the library context.
  46  */
  47 struct udev {
  48         int refcount;
  49         void (*log_fn)(struct udev *udev,
  50                        int priority, const char *file, int line, const char *fn,
  51                        const char *format, va_list args);
  52         void *userdata;
  53 };
  54
  55 /**
  56  * udev_get_userdata:
  57  * @udev: udev library context
  58  *
  59  * Retrieve stored data pointer from library context. This might be useful
  60  * to access from callbacks.
  61  *
  62  * Returns: stored userdata
  63  **/
  64 _public_ void *udev_get_userdata(struct udev *udev) {
  65         if (udev == NULL)
  66                 return NULL;
  67         return udev->userdata;
  68 }
  69
  70 /**
  71  * udev_set_userdata:
  72  * @udev: udev library context
  73  * @userdata: data pointer
  74  *
  75  * Store custom @userdata in the library context.
  76  **/
  77 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  78         if (udev == NULL)
  79                 return;
  80         udev->userdata = userdata;
  81 }
  82
  83 /**
  84  * udev_new:
  85  *
  86  * Create udev library context. This reads the udev configuration
  87  * file, and fills in the default values.
  88  *
  89  * The initial refcount is 1, and needs to be decremented to
  90  * release the resources of the udev library context.
  91  *
  92  * Returns: a new udev library context
  93  **/
  94 _public_ struct udev *udev_new(void) {
  95         struct udev *udev;
  96         _cleanup_fclose_ FILE *f = NULL;
  97
  98         udev = new0(struct udev, 1);
  99         if (udev == NULL)
 100                 return NULL;
 101         udev->refcount = 1;
 102
 103         f = fopen("/etc/udev/udev.conf", "re");
 104         if (f != NULL) {
 105                 char line[UTIL_LINE_SIZE];
 106                 unsigned line_nr = 0;
 107
 108                 while (fgets(line, sizeof(line), f)) {
 109                         size_t len;
 110                         char *key;
 111                         char *val;
 112
 113                         line_nr++;
 114
 115                         /* find key */
 116                         key = line;
 117                         while (isspace(key[0]))
 118                                 key++;
 119
 120                         /* comment or empty line */
 121                         if (key[0] == '#' || key[0] == '\0')
 122                                 continue;
 123
 124                         /* split key/value */
 125                         val = strchr(key, '=');
 126                         if (val == NULL) {
 127                                 log_debug("/etc/udev/udev.conf:%u: missing assignment,  skipping line.", line_nr);
 128                                 continue;
 129                         }
 130                         val[0] = '\0';
 131                         val++;
 132
 133                         /* find value */
 134                         while (isspace(val[0]))
 135                                 val++;
 136
 137                         /* terminate key */
 138                         len = strlen(key);
 139                         if (len == 0)
 140                                 continue;
 141                         while (isspace(key[len-1]))
 142                                 len--;
 143                         key[len] = '\0';
 144
 145                         /* terminate value */
 146                         len = strlen(val);
 147                         if (len == 0)
 148                                 continue;
 149                         while (isspace(val[len-1]))
 150                                 len--;
 151                         val[len] = '\0';
 152
 153                         if (len == 0)
 154                                 continue;
 155
 156                         /* unquote */
 157                         if (val[0] == '"' || val[0] == '\'') {
 158                                 if (val[len-1] != val[0]) {
 159                                         log_debug("/etc/udev/udev.conf:%u: inconsistent quoting, skipping line.", line_nr);
 160                                         continue;
 161                                 }
 162                                 val[len-1] = '\0';
 163                                 val++;
 164                         }
 165
 166                         if (streq(key, "udev_log")) {
 167                                 int prio;
 168
 169                                 prio = util_log_priority(val);
 170                                 if (prio < 0)
 171                                         log_debug("/etc/udev/udev.conf:%u: invalid log level '%s', ignoring.", line_nr, val);
 172                                 else
 173                                         log_set_max_level(prio);
 174                                 continue;
 175                         }
 176                 }
 177         }
 178
 179         return udev;
 180 }
 181
 182 /**
 183  * udev_ref:
 184  * @udev: udev library context
 185  *
 186  * Take a reference of the udev library context.
 187  *
 188  * Returns: the passed udev library context
 189  **/
 190 _public_ struct udev *udev_ref(struct udev *udev) {
 191         if (udev == NULL)
 192                 return NULL;
 193         udev->refcount++;
 194         return udev;
 195 }
 196
 197 /**
 198  * udev_unref:
 199  * @udev: udev library context
 200  *
 201  * Drop a reference of the udev library context. If the refcount
 202  * reaches zero, the resources of the context will be released.
 203  *
 204  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 205  **/
 206 _public_ struct udev *udev_unref(struct udev *udev) {
 207         if (udev == NULL)
 208                 return NULL;
 209         udev->refcount--;
 210         if (udev->refcount > 0)
 211                 return udev;
 212         free(udev);
 213         return NULL;
 214 }
 215
 216 /**
 217  * udev_set_log_fn:
 218  * @udev: udev library context
 219  * @log_fn: function to be called for log messages
 220  *
 221  * This function is deprecated.
 222  *
 223  **/
 224 _public_ void udev_set_log_fn(struct udev *udev,
 225                      void (*log_fn)(struct udev *udev,
 226                                     int priority, const char *file, int line, const char *fn,
 227                                     const char *format, va_list args)) {
 228         return;
 229 }
 230
 231 /**
 232  * udev_get_log_priority:
 233  * @udev: udev library context
 234  *
 235  * This function is deprecated.
 236  *
 237  **/
 238 _public_ int udev_get_log_priority(struct udev *udev) {
 239         return log_get_max_level();
 240 }
 241
 242 /**
 243  * udev_set_log_priority:
 244  * @udev: udev library context
 245  * @priority: the new log priority
 246  *
 247  * This function is deprecated.
 248  *
 249  **/
 250 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 251         log_set_max_level(priority);
 252 }