summaryrefslogtreecommitdiff
path: root/src/libudev/libudev-hwdb.c
blob: a53f000015468046157d84dd6f7f5ab72424b18a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/***
  This file is part of systemd.

  Copyright Tom Gundersen <teg@jklm.no>

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include "sd-hwdb.h"

#include "alloc-util.h"
#include "hwdb-util.h"
#include "libudev-private.h"

/**
 * SECTION:libudev-hwdb
 * @short_description: retrieve properties from the hardware database
 *
 * Libudev hardware database interface.
 */

/**
 * udev_hwdb:
 *
 * Opaque object representing the hardware database.
 */
struct udev_hwdb {
        struct udev *udev;
        int refcount;

        sd_hwdb *hwdb;

        struct udev_list properties_list;
};

/**
 * udev_hwdb_new:
 * @udev: udev library context
 *
 * Create a hardware database context to query properties for devices.
 *
 * Returns: a hwdb context.
 **/
_public_ struct udev_hwdb *udev_hwdb_new(struct udev *udev) {
        _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb_internal = NULL;
        struct udev_hwdb *hwdb;
        int r;

        assert_return(udev, NULL);

        r = sd_hwdb_new(&hwdb_internal);
        if (r < 0)
                return NULL;

        hwdb = new0(struct udev_hwdb, 1);
        if (!hwdb)
                return NULL;

        hwdb->refcount = 1;
        hwdb->hwdb = hwdb_internal;
        hwdb_internal = NULL;

        udev_list_init(udev, &hwdb->properties_list, true);

        return hwdb;
}

/**
 * udev_hwdb_ref:
 * @hwdb: context
 *
 * Take a reference of a hwdb context.
 *
 * Returns: the passed enumeration context
 **/
_public_ struct udev_hwdb *udev_hwdb_ref(struct udev_hwdb *hwdb) {
        if (!hwdb)
                return NULL;
        hwdb->refcount++;
        return hwdb;
}

/**
 * udev_hwdb_unref:
 * @hwdb: context
 *
 * Drop a reference of a hwdb context. If the refcount reaches zero,
 * all resources of the hwdb context will be released.
 *
 * Returns: #NULL
 **/
_public_ struct udev_hwdb *udev_hwdb_unref(struct udev_hwdb *hwdb) {
        if (!hwdb)
                return NULL;
        hwdb->refcount--;
        if (hwdb->refcount > 0)
                return NULL;
        sd_hwdb_unref(hwdb->hwdb);
        udev_list_cleanup(&hwdb->properties_list);
        free(hwdb);
        return NULL;
}

/**
 * udev_hwdb_get_properties_list_entry:
 * @hwdb: context
 * @modalias: modalias string
 * @flags: (unused)
 *
 * Lookup a matching device in the hardware database. The lookup key is a
 * modalias string, whose formats are defined for the Linux kernel modules.
 * Examples are: pci:v00008086d00001C2D*, usb:v04F2pB221*. The first entry
 * of a list of retrieved properties is returned.
 *
 * Returns: a udev_list_entry.
 */
_public_ struct udev_list_entry *udev_hwdb_get_properties_list_entry(struct udev_hwdb *hwdb, const char *modalias, unsigned int flags) {
        const char *key, *value;

        if (!hwdb || !modalias) {
                errno = EINVAL;
                return NULL;
        }

        udev_list_cleanup(&hwdb->properties_list);

        SD_HWDB_FOREACH_PROPERTY(hwdb->hwdb, modalias, key, value) {
                if (udev_list_entry_add(&hwdb->properties_list, key, value) == NULL) {
                        errno = ENOMEM;
                        return NULL;
                }
        }

        return udev_list_get_entry(&hwdb->properties_list);
}