src/libudev/libudev.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2008-2014 Kay Sievers <kay@vrfy.org>
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <ctype.h>
  22 #include <stdarg.h>
  23 #include <stddef.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include "libudev.h"
  29
  30 #include "alloc-util.h"
  31 #include "fd-util.h"
  32 #include "libudev-private.h"
  33 #include "missing.h"
  34 #include "string-util.h"
  35
  36 /**
  37  * SECTION:libudev
  38  * @short_description: libudev context
  39  *
  40  * The context contains the default values read from the udev config file,
  41  * and is passed to all library operations.
  42  */
  43
  44 /**
  45  * udev:
  46  *
  47  * Opaque object representing the library context.
  48  */
  49 struct udev {
  50         int refcount;
  51         void (*log_fn)(struct udev *udev,
  52                        int priority, const char *file, int line, const char *fn,
  53                        const char *format, va_list args);
  54         void *userdata;
  55 };
  56
  57 /**
  58  * udev_get_userdata:
  59  * @udev: udev library context
  60  *
  61  * Retrieve stored data pointer from library context. This might be useful
  62  * to access from callbacks.
  63  *
  64  * Returns: stored userdata
  65  **/
  66 _public_ void *udev_get_userdata(struct udev *udev) {
  67         if (udev == NULL)
  68                 return NULL;
  69         return udev->userdata;
  70 }
  71
  72 /**
  73  * udev_set_userdata:
  74  * @udev: udev library context
  75  * @userdata: data pointer
  76  *
  77  * Store custom @userdata in the library context.
  78  **/
  79 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  80         if (udev == NULL)
  81                 return;
  82         udev->userdata = userdata;
  83 }
  84
  85 /**
  86  * udev_new:
  87  *
  88  * Create udev library context. This reads the udev configuration
  89  * file, and fills in the default values.
  90  *
  91  * The initial refcount is 1, and needs to be decremented to
  92  * release the resources of the udev library context.
  93  *
  94  * Returns: a new udev library context
  95  **/
  96 _public_ struct udev *udev_new(void) {
  97         struct udev *udev;
  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 }