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 "alloc-util.h"
  30 #include "fd-util.h"
  31 #include "libudev-private.h"
  32 #include "missing.h"
  33 #include "string-util.h"
  34
  35 /**
  36  * SECTION:libudev
  37  * @short_description: libudev context
  38  *
  39  * The context contains the default values read from the udev config file,
  40  * and is passed to all library operations.
  41  */
  42
  43 /**
  44  * udev:
  45  *
  46  * Opaque object representing the library context.
  47  */
  48 struct udev {
  49         int refcount;
  50         void (*log_fn)(struct udev *udev,
  51                        int priority, const char *file, int line, const char *fn,
  52                        const char *format, va_list args);
  53         void *userdata;
  54 };
  55
  56 /**
  57  * udev_get_userdata:
  58  * @udev: udev library context
  59  *
  60  * Retrieve stored data pointer from library context. This might be useful
  61  * to access from callbacks.
  62  *
  63  * Returns: stored userdata
  64  **/
  65 _public_ void *udev_get_userdata(struct udev *udev) {
  66         if (udev == NULL)
  67                 return NULL;
  68         return udev->userdata;
  69 }
  70
  71 /**
  72  * udev_set_userdata:
  73  * @udev: udev library context
  74  * @userdata: data pointer
  75  *
  76  * Store custom @userdata in the library context.
  77  **/
  78 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  79         if (udev == NULL)
  80                 return;
  81         udev->userdata = userdata;
  82 }
  83
  84 /**
  85  * udev_new:
  86  *
  87  * Create udev library context. This reads the udev configuration
  88  * file, and fills in the default values.
  89  *
  90  * The initial refcount is 1, and needs to be decremented to
  91  * release the resources of the udev library context.
  92  *
  93  * Returns: a new udev library context
  94  **/
  95 _public_ struct udev *udev_new(void) {
  96         struct udev *udev;
  97         _cleanup_fclose_ FILE *f = NULL;
  98
  99         udev = new0(struct udev, 1);
 100         if (!udev) {
 101                 errno = -ENOMEM;
 102                 return NULL;
 103         }
 104         udev->refcount = 1;
 105
 106         return udev;
 107 }
 108
 109 /**
 110  * udev_ref:
 111  * @udev: udev library context
 112  *
 113  * Take a reference of the udev library context.
 114  *
 115  * Returns: the passed udev library context
 116  **/
 117 _public_ struct udev *udev_ref(struct udev *udev) {
 118         if (udev == NULL)
 119                 return NULL;
 120         udev->refcount++;
 121         return udev;
 122 }
 123
 124 /**
 125  * udev_unref:
 126  * @udev: udev library context
 127  *
 128  * Drop a reference of the udev library context. If the refcount
 129  * reaches zero, the resources of the context will be released.
 130  *
 131  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 132  **/
 133 _public_ struct udev *udev_unref(struct udev *udev) {
 134         if (udev == NULL)
 135                 return NULL;
 136         udev->refcount--;
 137         if (udev->refcount > 0)
 138                 return udev;
 139         free(udev);
 140         return NULL;
 141 }
 142
 143 /**
 144  * udev_set_log_fn:
 145  * @udev: udev library context
 146  * @log_fn: function to be called for log messages
 147  *
 148  * This function is deprecated.
 149  *
 150  **/
 151 _public_ void udev_set_log_fn(struct udev *udev,
 152                      void (*log_fn)(struct udev *udev,
 153                                     int priority, const char *file, int line, const char *fn,
 154                                     const char *format, va_list args)) {
 155         return;
 156 }
 157
 158 /**
 159  * udev_get_log_priority:
 160  * @udev: udev library context
 161  *
 162  * This function is deprecated.
 163  *
 164  **/
 165 _public_ int udev_get_log_priority(struct udev *udev) {
 166         return log_get_max_level();
 167 }
 168
 169 /**
 170  * udev_set_log_priority:
 171  * @udev: udev library context
 172  * @priority: the new log priority
 173  *
 174  * This function is deprecated.
 175  *
 176  **/
 177 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 178         log_set_max_level(priority);
 179 }