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
   8 #include <ctype.h>
   9 #include <stdarg.h>
  10 #include <stddef.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14
  15 #include "libudev.h"
  16
  17 #include "alloc-util.h"
  18 #include "fd-util.h"
  19 #include "libudev-private.h"
  20 #include "missing.h"
  21 #include "string-util.h"
  22
  23 /**
  24  * SECTION:libudev
  25  * @short_description: libudev context
  26  *
  27  * The context contains the default values read from the udev config file,
  28  * and is passed to all library operations.
  29  */
  30
  31 /**
  32  * udev:
  33  *
  34  * Opaque object representing the library context.
  35  */
  36 struct udev {
  37         int refcount;
  38         void (*log_fn)(struct udev *udev,
  39                        int priority, const char *file, int line, const char *fn,
  40                        const char *format, va_list args);
  41         void *userdata;
  42 };
  43
  44 /**
  45  * udev_get_userdata:
  46  * @udev: udev library context
  47  *
  48  * Retrieve stored data pointer from library context. This might be useful
  49  * to access from callbacks.
  50  *
  51  * Returns: stored userdata
  52  **/
  53 _public_ void *udev_get_userdata(struct udev *udev) {
  54         if (udev == NULL)
  55                 return NULL;
  56         return udev->userdata;
  57 }
  58
  59 /**
  60  * udev_set_userdata:
  61  * @udev: udev library context
  62  * @userdata: data pointer
  63  *
  64  * Store custom @userdata in the library context.
  65  **/
  66 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  67         if (udev == NULL)
  68                 return;
  69         udev->userdata = userdata;
  70 }
  71
  72 /**
  73  * udev_new:
  74  *
  75  * Create udev library context. This only allocates the basic data structure.
  76  *
  77  * The initial refcount is 1, and needs to be decremented to
  78  * release the resources of the udev library context.
  79  *
  80  * Returns: a new udev library context
  81  **/
  82 _public_ struct udev *udev_new(void) {
  83         struct udev *udev;
  84
  85         udev = new0(struct udev, 1);
  86         if (!udev) {
  87                 errno = ENOMEM;
  88                 return NULL;
  89         }
  90         udev->refcount = 1;
  91
  92         return udev;
  93 }
  94
  95 /**
  96  * udev_ref:
  97  * @udev: udev library context
  98  *
  99  * Take a reference of the udev library context.
 100  *
 101  * Returns: the passed udev library context
 102  **/
 103 _public_ struct udev *udev_ref(struct udev *udev) {
 104         if (udev == NULL)
 105                 return NULL;
 106         udev->refcount++;
 107         return udev;
 108 }
 109
 110 /**
 111  * udev_unref:
 112  * @udev: udev library context
 113  *
 114  * Drop a reference of the udev library context. If the refcount
 115  * reaches zero, the resources of the context will be released.
 116  *
 117  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 118  **/
 119 _public_ struct udev *udev_unref(struct udev *udev) {
 120         if (udev == NULL)
 121                 return NULL;
 122         udev->refcount--;
 123         if (udev->refcount > 0)
 124                 return udev;
 125         return mfree(udev);
 126 }
 127
 128 /**
 129  * udev_set_log_fn:
 130  * @udev: udev library context
 131  * @log_fn: function to be called for log messages
 132  *
 133  * This function is deprecated.
 134  *
 135  **/
 136 _public_ void udev_set_log_fn(struct udev *udev,
 137                      void (*log_fn)(struct udev *udev,
 138                                     int priority, const char *file, int line, const char *fn,
 139                                     const char *format, va_list args)) {
 140         return;
 141 }
 142
 143 /**
 144  * udev_get_log_priority:
 145  * @udev: udev library context
 146  *
 147  * This function is deprecated.
 148  *
 149  **/
 150 _public_ int udev_get_log_priority(struct udev *udev) {
 151         return log_get_max_level();
 152 }
 153
 154 /**
 155  * udev_set_log_priority:
 156  * @udev: udev library context
 157  * @priority: the new log priority
 158  *
 159  * This function is deprecated.
 160  *
 161  **/
 162 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 163         log_set_max_level(priority);
 164 }