libudev: hide definition of struct udev_list from other libudev components
[thirdparty/systemd.git] / src / libudev / libudev-hwdb.c
1 /* SPDX-License-Identifier: LGPL-2.1+ */
2
3 #include <errno.h>
4
5 #include "sd-hwdb.h"
6
7 #include "alloc-util.h"
8 #include "hwdb-util.h"
9 #include "libudev-list-internal.h"
10
11 /**
12  * SECTION:libudev-hwdb
13  * @short_description: retrieve properties from the hardware database
14  *
15  * Libudev hardware database interface.
16  */
17
18 /**
19  * udev_hwdb:
20  *
21  * Opaque object representing the hardware database.
22  */
23 struct udev_hwdb {
24         unsigned n_ref;
25         sd_hwdb *hwdb;
26         struct udev_list *properties_list;
27 };
28
29 /**
30  * udev_hwdb_new:
31  * @udev: udev library context (unused)
32  *
33  * Create a hardware database context to query properties for devices.
34  *
35  * Returns: a hwdb context.
36  **/
37 _public_ struct udev_hwdb *udev_hwdb_new(struct udev *udev) {
38         _cleanup_(udev_list_freep) struct udev_list *list = NULL;
39         _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb_internal = NULL;
40         struct udev_hwdb *hwdb;
41         int r;
42
43         r = sd_hwdb_new(&hwdb_internal);
44         if (r < 0)
45                 return_with_errno(NULL, r);
46
47         list = udev_list_new(true);
48         if (!list)
49                 return_with_errno(NULL, ENOMEM);
50
51         hwdb = new(struct udev_hwdb, 1);
52         if (!hwdb)
53                 return_with_errno(NULL, ENOMEM);
54
55         *hwdb = (struct udev_hwdb) {
56                 .n_ref = 1,
57                 .hwdb = TAKE_PTR(hwdb_internal),
58                 .properties_list = TAKE_PTR(list),
59         };
60
61         return hwdb;
62 }
63
64 static struct udev_hwdb *udev_hwdb_free(struct udev_hwdb *hwdb) {
65         assert(hwdb);
66
67         sd_hwdb_unref(hwdb->hwdb);
68         udev_list_free(hwdb->properties_list);
69         return mfree(hwdb);
70 }
71
72 /**
73  * udev_hwdb_ref:
74  * @hwdb: context
75  *
76  * Take a reference of a hwdb context.
77  *
78  * Returns: the passed enumeration context
79  **/
80
81 /**
82  * udev_hwdb_unref:
83  * @hwdb: context
84  *
85  * Drop a reference of a hwdb context. If the refcount reaches zero,
86  * all resources of the hwdb context will be released.
87  *
88  * Returns: #NULL
89  **/
90 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(struct udev_hwdb, udev_hwdb, udev_hwdb_free);
91
92 /**
93  * udev_hwdb_get_properties_list_entry:
94  * @hwdb: context
95  * @modalias: modalias string
96  * @flags: (unused)
97  *
98  * Lookup a matching device in the hardware database. The lookup key is a
99  * modalias string, whose formats are defined for the Linux kernel modules.
100  * Examples are: pci:v00008086d00001C2D*, usb:v04F2pB221*. The first entry
101  * of a list of retrieved properties is returned.
102  *
103  * Returns: a udev_list_entry.
104  */
105 _public_ struct udev_list_entry *udev_hwdb_get_properties_list_entry(struct udev_hwdb *hwdb, const char *modalias, unsigned flags) {
106         const char *key, *value;
107         struct udev_list_entry *e;
108
109         assert_return_errno(hwdb, NULL, EINVAL);
110         assert_return_errno(modalias, NULL, EINVAL);
111
112         udev_list_cleanup(hwdb->properties_list);
113
114         SD_HWDB_FOREACH_PROPERTY(hwdb->hwdb, modalias, key, value)
115                 if (!udev_list_entry_add(hwdb->properties_list, key, value))
116                         return_with_errno(NULL, ENOMEM);
117
118         e = udev_list_get_entry(hwdb->properties_list);
119         if (!e)
120                 return_with_errno(NULL, ENODATA);
121
122         return e;
123 }