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 "libudev-private.h"
  15 #include "missing.h"
  16 #include "string-util.h"
  17
  18 /**
  19  * SECTION:libudev
  20  * @short_description: libudev context
  21  */
  22
  23 /**
  24  * udev:
  25  *
  26  * Opaque object representing the library context.
  27  */
  28 struct udev {
  29         unsigned n_ref;
  30         void *userdata;
  31 };
  32
  33 /**
  34  * udev_get_userdata:
  35  * @udev: udev library context
  36  *
  37  * Retrieve stored data pointer from library context. This might be useful
  38  * to access from callbacks.
  39  *
  40  * Returns: stored userdata
  41  **/
  42 _public_ void *udev_get_userdata(struct udev *udev) {
  43         assert_return(udev, NULL);
  44
  45         return udev->userdata;
  46 }
  47
  48 /**
  49  * udev_set_userdata:
  50  * @udev: udev library context
  51  * @userdata: data pointer
  52  *
  53  * Store custom @userdata in the library context.
  54  **/
  55 _public_ void udev_set_userdata(struct udev *udev, void *userdata) {
  56         if (!udev)
  57                 return;
  58
  59         udev->userdata = userdata;
  60 }
  61
  62 /**
  63  * udev_new:
  64  *
  65  * Create udev library context. This only allocates the basic data structure.
  66  *
  67  * The initial refcount is 1, and needs to be decremented to
  68  * release the resources of the udev library context.
  69  *
  70  * Returns: a new udev library context
  71  **/
  72 _public_ struct udev *udev_new(void) {
  73         struct udev *udev;
  74
  75         udev = new(struct udev, 1);
  76         if (!udev) {
  77                 errno = ENOMEM;
  78                 return NULL;
  79         }
  80
  81         *udev = (struct udev) {
  82                 .n_ref = 1,
  83         };
  84
  85         return udev;
  86 }
  87
  88 /**
  89  * udev_ref:
  90  * @udev: udev library context
  91  *
  92  * Take a reference of the udev library context.
  93  *
  94  * Returns: the passed udev library context
  95  **/
  96 DEFINE_PUBLIC_TRIVIAL_REF_FUNC(struct udev, udev);
  97
  98 /**
  99  * udev_unref:
 100  * @udev: udev library context
 101  *
 102  * Drop a reference of the udev library context. If the refcount
 103  * reaches zero, the resources of the context will be released.
 104  *
 105  * Returns: the passed udev library context if it has still an active reference, or #NULL otherwise.
 106  **/
 107 _public_ struct udev *udev_unref(struct udev *udev) {
 108         if (!udev)
 109                 return NULL;
 110
 111         assert(udev->n_ref > 0);
 112         udev->n_ref--;
 113         if (udev->n_ref > 0)
 114                 /* This is different from our convetion, but let's keep backward
 115                  * compatibility. So, do not use DEFINE_PUBLIC_TRIVIAL_UNREF_FUNC()
 116                  * macro to define this function. */
 117                 return udev;
 118
 119         return mfree(udev);
 120 }
 121
 122 /**
 123  * udev_set_log_fn:
 124  * @udev: udev library context
 125  * @log_fn: function to be called for log messages
 126  *
 127  * This function is deprecated.
 128  *
 129  **/
 130 _public_ void udev_set_log_fn(
 131                         struct udev *udev,
 132                         void (*log_fn)(struct udev *udev,
 133                                        int priority, const char *file, int line, const char *fn,
 134                                        const char *format, va_list args)) {
 135         return;
 136 }
 137
 138 /**
 139  * udev_get_log_priority:
 140  * @udev: udev library context
 141  *
 142  * This function is deprecated.
 143  *
 144  **/
 145 _public_ int udev_get_log_priority(struct udev *udev) {
 146         return log_get_max_level();
 147 }
 148
 149 /**
 150  * udev_set_log_priority:
 151  * @udev: udev library context
 152  * @priority: the new log priority
 153  *
 154  * This function is deprecated.
 155  *
 156  **/
 157 _public_ void udev_set_log_priority(struct udev *udev, int priority) {
 158         log_set_max_level(priority);
 159 }