src/libudev/libudev.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <ctype.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9
  10 #include "libudev.h"
  11
  12 #include "alloc-util.h"
  13 #include "fd-util.h"
  14 #include "missing.h"
  15 #include "string-util.h"
  16
  17 /**
  18  * SECTION:libudev
  19  * @short_description: libudev context
  20  */
  21
  22 /**
  23  * udev:
  24  *
  25  * Opaque object representing the library context.
  26  */
  27 struct udev {
  28         unsigned n_ref;
  29         void *userdata;
  30 };
  31
  32 /**
  33  * udev_get_userdata:
  34  * @udev: udev library context
  35  *
  36  * Retrieve stored data pointer from library context. This might be useful
  37  * to access from callbacks.
  38  *
  39  * Returns: stored userdata
  40  **/
  41 _public_ void *udev_get_userdata(struct udev *udev) {
  42         assert_return(udev, NULL);
  43
  44         return udev->userdata;
  45 }
  46
  47 /**
  48  * udev_set_userdata:
  49  * @udev: udev library context
  50  * @userdata: data pointer
  51  *
  52  * Store custom @userdata in the library context.
  53  **/
  54 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  55         if (!udev)
  56                 return;
  57
  58         udev->userdata = userdata;
  59 }
  60
  61 /**
  62  * udev_new:
  63  *
  64  * Create udev library context. This only allocates the basic data structure.
  65  *
  66  * The initial refcount is 1, and needs to be decremented to
  67  * release the resources of the udev library context.
  68  *
  69  * Returns: a new udev library context
  70  **/
  71 _public_ struct udev *udev_new(void) {
  72         struct udev *udev;
  73
  74         udev = new(struct udev, 1);
  75         if (!udev)
  76                 return_with_errno(NULL, ENOMEM);
  77
  78         *udev = (struct udev) {
  79                 .n_ref = 1,
  80         };
  81
  82         return udev;
  83 }
  84
  85 /**
  86  * udev_ref:
  87  * @udev: udev library context
  88  *
  89  * Take a reference of the udev library context.
  90  *
  91  * Returns: the passed udev library context
  92  **/
  93 DEFINE_PUBLIC_TRIVIAL_REF_FUNC(struct udev, udev);
  94
  95 /**
  96  * udev_unref:
  97  * @udev: udev library context
  98  *
  99  * Drop a reference of the udev library context. If the refcount
 100  * reaches zero, the resources of the context will be released.
 101  *
 102  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 103  **/
 104 _public_ struct udev *udev_unref(struct udev *udev) {
 105         if (!udev)
 106                 return NULL;
 107
 108         assert(udev->n_ref > 0);
 109         udev->n_ref--;
 110         if (udev->n_ref > 0)
 111                 /* This is different from our convetion, but let's keep backward
 112                  * compatibility. So, do not use DEFINE_PUBLIC_TRIVIAL_UNREF_FUNC()
 113                  * macro to define this function. */
 114                 return udev;
 115
 116         return mfree(udev);
 117 }
 118
 119 /**
 120  * udev_set_log_fn:
 121  * @udev: udev library context
 122  * @log_fn: function to be called for log messages
 123  *
 124  * This function is deprecated.
 125  *
 126  **/
 127 _public_ void udev_set_log_fn(
 128                         struct udev *udev,
 129                         void (*log_fn)(struct udev *udev,
 130                                        int priority, const char *file, int line, const char *fn,
 131                                        const char *format, va_list args)) {
 132         return;
 133 }
 134
 135 /**
 136  * udev_get_log_priority:
 137  * @udev: udev library context
 138  *
 139  * This function is deprecated.
 140  *
 141  **/
 142 _public_ int udev_get_log_priority(struct udev *udev) {
 143         return log_get_max_level();
 144 }
 145
 146 /**
 147  * udev_set_log_priority:
 148  * @udev: udev library context
 149  * @priority: the new log priority
 150  *
 151  * This function is deprecated.
 152  *
 153  **/
 154 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 155         log_set_max_level(priority);
 156 }