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 only allocates the basic data structure.
  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
  98         udev = new0(struct udev, 1);
  99         if (!udev) {
 100                 errno = ENOMEM;
 101                 return NULL;
 102         }
 103         udev->refcount = 1;
 104
 105         return udev;
 106 }
 107
 108 /**
 109  * udev_ref:
 110  * @udev: udev library context
 111  *
 112  * Take a reference of the udev library context.
 113  *
 114  * Returns: the passed udev library context
 115  **/
 116 _public_ struct udev *udev_ref(struct udev *udev) {
 117         if (udev == NULL)
 118                 return NULL;
 119         udev->refcount++;
 120         return udev;
 121 }
 122
 123 /**
 124  * udev_unref:
 125  * @udev: udev library context
 126  *
 127  * Drop a reference of the udev library context. If the refcount
 128  * reaches zero, the resources of the context will be released.
 129  *
 130  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 131  **/
 132 _public_ struct udev *udev_unref(struct udev *udev) {
 133         if (udev == NULL)
 134                 return NULL;
 135         udev->refcount--;
 136         if (udev->refcount > 0)
 137                 return udev;
 138         return mfree(udev);
 139 }
 140
 141 /**
 142  * udev_set_log_fn:
 143  * @udev: udev library context
 144  * @log_fn: function to be called for log messages
 145  *
 146  * This function is deprecated.
 147  *
 148  **/
 149 _public_ void udev_set_log_fn(struct udev *udev,
 150                      void (*log_fn)(struct udev *udev,
 151                                     int priority, const char *file, int line, const char *fn,
 152                                     const char *format, va_list args)) {
 153         return;
 154 }
 155
 156 /**
 157  * udev_get_log_priority:
 158  * @udev: udev library context
 159  *
 160  * This function is deprecated.
 161  *
 162  **/
 163 _public_ int udev_get_log_priority(struct udev *udev) {
 164         return log_get_max_level();
 165 }
 166
 167 /**
 168  * udev_set_log_priority:
 169  * @udev: udev library context
 170  * @priority: the new log priority
 171  *
 172  * This function is deprecated.
 173  *
 174  **/
 175 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 176         log_set_max_level(priority);
 177 }