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