summaryrefslogtreecommitdiff
path: root/src/libudev/libudev-hwdb.c
blob: 7af230c40e948e9b98cb67f9cc470e91b458050e (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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
/***
  This file is part of systemd.

  Copyright 2012 Kay Sievers <kay@vrfy.org>
  Copyright 2008 Alan Jenkins <alan.christopher.jenkins@googlemail.com>

  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 <stdio.h>
#include <errno.h>
#include <string.h>
#include <inttypes.h>
#include <ctype.h>
#include <stdlib.h>
#include <fnmatch.h>
#include <getopt.h>
#include <sys/mman.h>

#include "libudev-private.h"
#include "libudev-hwdb-def.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;

        FILE *f;
        struct stat st;
        union {
                struct trie_header_f *head;
                const char *map;
        };

        struct udev_list properties_list;
};

struct linebuf {
        char bytes[LINE_MAX];
        size_t size;
        size_t len;
};

static void linebuf_init(struct linebuf *buf) {
        buf->size = 0;
        buf->len = 0;
}

static const char *linebuf_get(struct linebuf *buf) {
        if (buf->len + 1 >= sizeof(buf->bytes))
                return NULL;
        buf->bytes[buf->len] = '\0';
        return buf->bytes;
}

static bool linebuf_add(struct linebuf *buf, const char *s, size_t len) {
        if (buf->len + len >= sizeof(buf->bytes))
                return false;
        memcpy(buf->bytes + buf->len, s, len);
        buf->len += len;
        return true;
}

static bool linebuf_add_char(struct linebuf *buf, char c)
{
        if (buf->len + 1 >= sizeof(buf->bytes))
                return false;
        buf->bytes[buf->len++] = c;
        return true;
}

static void linebuf_rem(struct linebuf *buf, size_t count) {
        assert(buf->len >= count);
        buf->len -= count;
}

static void linebuf_rem_char(struct linebuf *buf) {
        linebuf_rem(buf, 1);
}

static const struct trie_child_entry_f *trie_node_children(struct udev_hwdb *hwdb, const struct trie_node_f *node) {
        return (const struct trie_child_entry_f *)((const char *)node + le64toh(hwdb->head->node_size));
}

static const struct trie_value_entry_f *trie_node_values(struct udev_hwdb *hwdb, const struct trie_node_f *node) {
        const char *base = (const char *)node;

        base += le64toh(hwdb->head->node_size);
        base += node->children_count * le64toh(hwdb->head->child_entry_size);
        return (const struct trie_value_entry_f *)base;
}

static const struct trie_node_f *trie_node_from_off(struct udev_hwdb *hwdb, le64_t off) {
        return (const struct trie_node_f *)(hwdb->map + le64toh(off));
}

static const char *trie_string(struct udev_hwdb *hwdb, le64_t off) {
        return hwdb->map + le64toh(off);
}

static int trie_children_cmp_f(const void *v1, const void *v2) {
        const struct trie_child_entry_f *n1 = v1;
        const struct trie_child_entry_f *n2 = v2;

        return n1->c - n2->c;
}

static const struct trie_node_f *node_lookup_f(struct udev_hwdb *hwdb, const struct trie_node_f *node, uint8_t c) {
        struct trie_child_entry_f *child;
        struct trie_child_entry_f search;

        search.c = c;
        child = bsearch(&search, trie_node_children(hwdb, node), node->children_count,
                        le64toh(hwdb->head->child_entry_size), trie_children_cmp_f);
        if (child)
                return trie_node_from_off(hwdb, child->child_off);
        return NULL;
}

static int hwdb_add_property(struct udev_hwdb *hwdb, const char *key, const char *value) {
        /*
         * Silently ignore all properties which do not start with a
         * space; future extensions might use additional prefixes.
         */
        if (key[0] != ' ')
                return 0;

        if (udev_list_entry_add(&hwdb->properties_list, key+1, value) == NULL)
                return -ENOMEM;
        return 0;
}

static int trie_fnmatch_f(struct udev_hwdb *hwdb, const struct trie_node_f *node, size_t p,
                          struct linebuf *buf, const char *search) {
        size_t len;
        size_t i;
        const char *prefix;
        int err;

        prefix = trie_string(hwdb, node->prefix_off);
        len = strlen(prefix + p);
        linebuf_add(buf, prefix + p, len);

        for (i = 0; i < node->children_count; i++) {
                const struct trie_child_entry_f *child = &trie_node_children(hwdb, node)[i];

                linebuf_add_char(buf, child->c);
                err = trie_fnmatch_f(hwdb, trie_node_from_off(hwdb, child->child_off), 0, buf, search);
                if (err < 0)
                        return err;
                linebuf_rem_char(buf);
        }

        if (le64toh(node->values_count) && fnmatch(linebuf_get(buf), search, 0) == 0)
                for (i = 0; i < le64toh(node->values_count); i++) {
                        err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_values(hwdb, node)[i].key_off),
                                                trie_string(hwdb, trie_node_values(hwdb, node)[i].value_off));
                        if (err < 0)
                                return err;
                }

        linebuf_rem(buf, len);
        return 0;
}

static int trie_search_f(struct udev_hwdb *hwdb, const char *search) {
        struct linebuf buf;
        const struct trie_node_f *node;
        size_t i = 0;
        int err;

        linebuf_init(&buf);

        node = trie_node_from_off(hwdb, hwdb->head->nodes_root_off);
        while (node) {
                const struct trie_node_f *child;
                size_t p = 0;

                if (node->prefix_off) {
                        uint8_t c;

                        for (; (c = trie_string(hwdb, node->prefix_off)[p]); p++) {
                                if (c == '*' || c == '?' || c == '[')
                                        return trie_fnmatch_f(hwdb, node, p, &buf, search + i + p);
                                if (c != search[i + p])
                                        return 0;
                        }
                        i += p;
                }

                child = node_lookup_f(hwdb, node, '*');
                if (child) {
                        linebuf_add_char(&buf, '*');
                        err = trie_fnmatch_f(hwdb, child, 0, &buf, search + i);
                        if (err < 0)
                                return err;
                        linebuf_rem_char(&buf);
                }

                child = node_lookup_f(hwdb, node, '?');
                if (child) {
                        linebuf_add_char(&buf, '?');
                        err = trie_fnmatch_f(hwdb, child, 0, &buf, search + i);
                        if (err < 0)
                                return err;
                        linebuf_rem_char(&buf);
                }

                child = node_lookup_f(hwdb, node, '[');
                if (child) {
                        linebuf_add_char(&buf, '[');
                        err = trie_fnmatch_f(hwdb, child, 0, &buf, search + i);
                        if (err < 0)
                                return err;
                        linebuf_rem_char(&buf);
                }

                if (search[i] == '\0') {
                        size_t n;

                        for (n = 0; n < le64toh(node->values_count); n++) {
                                err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_values(hwdb, node)[n].key_off),
                                                        trie_string(hwdb, trie_node_values(hwdb, node)[n].value_off));
                                if (err < 0)
                                        return err;
                        }
                        return 0;
                }

                child = node_lookup_f(hwdb, node, search[i]);
                node = child;
                i++;
        }
        return 0;
}

/**
 * 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) {
        struct udev_hwdb *hwdb;
        const char sig[] = HWDB_SIG;

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

        hwdb->refcount = 1;
        udev_list_init(udev, &hwdb->properties_list, true);

        hwdb->f = fopen(UDEV_HWDB_BIN, "re");
        if (!hwdb->f) {
                udev_dbg(udev, "error reading " UDEV_HWDB_BIN ": %m");
                udev_hwdb_unref(hwdb);
                return NULL;
        }

        if (fstat(fileno(hwdb->f), &hwdb->st) < 0 ||
            (size_t)hwdb->st.st_size < offsetof(struct trie_header_f, strings_len) + 8) {
                udev_dbg(udev, "error reading " UDEV_HWDB_BIN ": %m");
                udev_hwdb_unref(hwdb);
                return NULL;
        }

        hwdb->map = mmap(0, hwdb->st.st_size, PROT_READ, MAP_SHARED, fileno(hwdb->f), 0);
        if (hwdb->map == MAP_FAILED) {
                udev_dbg(udev, "error mapping " UDEV_HWDB_BIN ": %m");
                udev_hwdb_unref(hwdb);
                return NULL;
        }

        if (memcmp(hwdb->map, sig, sizeof(hwdb->head->signature)) != 0 ||
            (size_t)hwdb->st.st_size != le64toh(hwdb->head->file_size)) {
                udev_dbg(udev, "error recognizing the format of " UDEV_HWDB_BIN);
                udev_hwdb_unref(hwdb);
                return NULL;
        }

        udev_dbg(udev, "=== trie on-disk ===\n");
        udev_dbg(udev, "tool version:          %"PRIu64, le64toh(hwdb->head->tool_version));
        udev_dbg(udev, "file size:        %8zu bytes\n", hwdb->st.st_size);
        udev_dbg(udev, "header size       %8"PRIu64" bytes\n", le64toh(hwdb->head->header_size));
        udev_dbg(udev, "strings           %8"PRIu64" bytes\n", le64toh(hwdb->head->strings_len));
        udev_dbg(udev, "nodes             %8"PRIu64" bytes\n", le64toh(hwdb->head->nodes_len));
        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;
        if (hwdb->map)
                munmap((void *)hwdb->map, hwdb->st.st_size);
        if (hwdb->f)
                fclose(hwdb->f);
        udev_list_cleanup(&hwdb->properties_list);
        free(hwdb);
        return NULL;
}

bool udev_hwdb_validate(struct udev_hwdb *hwdb) {
        struct stat st;

        if (!hwdb)
                return false;
        if (!hwdb->f)
                return false;
        if (stat("/etc/udev/hwdb.bin", &st) < 0)
                return true;
        if (timespec_load(&hwdb->st.st_mtim) != timespec_load(&st.st_mtim))
                return true;
        return false;
}

/**
 * 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) {
        int err;

        if (!hwdb || !hwdb->f) {
                errno = EINVAL;
                return NULL;
        }

        udev_list_cleanup(&hwdb->properties_list);
        err = trie_search_f(hwdb, modalias);
        if (err < 0) {
                errno = -err;
                return NULL;
        }
        return udev_list_get_entry(&hwdb->properties_list);
}