src/libudev/libudev.c

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