summaryrefslogtreecommitdiff
path: root/src/hwdb/hwdb.c
blob: 9f8cbf6c795447bb0b826cdd95af2c2fe74f72d5 (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
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
/***
  This file is part of systemd.

  Copyright 2012 Kay Sievers <kay@vrfy.org>

  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 <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <string.h>
#include <ctype.h>

#include "util.h"
#include "strbuf.h"
#include "conf-files.h"
#include "strv.h"
#include "mkdir.h"
#include "fileio.h"

#include "hwdb-internal.h"
#include "hwdb-util.h"

/*
 * Generic udev properties, key/value database based on modalias strings.
 * Uses a Patricia/radix trie to index all matches for efficient lookup.
 */

static const char *arg_hwdb_bin_dir = "/etc/udev";
static const char *arg_root = "";

static const char * const conf_file_dirs[] = {
        "/etc/udev/hwdb.d",
        UDEVLIBEXECDIR "/hwdb.d",
        NULL
};

/* in-memory trie objects */
struct trie {
        struct trie_node *root;
        struct strbuf *strings;

        size_t nodes_count;
        size_t children_count;
        size_t values_count;
};

struct trie_node {
        /* prefix, common part for all children of this node */
        size_t prefix_off;

        /* sorted array of pointers to children nodes */
        struct trie_child_entry *children;
        uint8_t children_count;

        /* sorted array of key/value pairs */
        struct trie_value_entry *values;
        size_t values_count;
};

/* children array item with char (0-255) index */
struct trie_child_entry {
        uint8_t c;
        struct trie_node *child;
};

/* value array item with key/value pairs */
struct trie_value_entry {
        size_t key_off;
        size_t value_off;
};

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

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

static int node_add_child(struct trie *trie, struct trie_node *node, struct trie_node *node_child, uint8_t c) {
        struct trie_child_entry *child;

        /* extend array, add new entry, sort for bisection */
        child = realloc(node->children, (node->children_count + 1) * sizeof(struct trie_child_entry));
        if (!child)
                return -ENOMEM;

        node->children = child;
        trie->children_count++;
        node->children[node->children_count].c = c;
        node->children[node->children_count].child = node_child;
        node->children_count++;
        qsort(node->children, node->children_count, sizeof(struct trie_child_entry), trie_children_cmp);
        trie->nodes_count++;

        return 0;
}

static struct trie_node *node_lookup(const struct trie_node *node, uint8_t c) {
        struct trie_child_entry *child;
        struct trie_child_entry search;

        search.c = c;
        child = bsearch(&search, node->children, node->children_count, sizeof(struct trie_child_entry), trie_children_cmp);
        if (child)
                return child->child;
        return NULL;
}

static void trie_node_cleanup(struct trie_node *node) {
        size_t i;

        for (i = 0; i < node->children_count; i++)
                trie_node_cleanup(node->children[i].child);
        free(node->children);
        free(node->values);
        free(node);
}

static void trie_free(struct trie *trie) {
        if (!trie)
                return;

        if (trie->root)
                trie_node_cleanup(trie->root);

        strbuf_cleanup(trie->strings);
        free(trie);
}

DEFINE_TRIVIAL_CLEANUP_FUNC(struct trie*, trie_free);

static int trie_values_cmp(const void *v1, const void *v2, void *arg) {
        const struct trie_value_entry *val1 = v1;
        const struct trie_value_entry *val2 = v2;
        struct trie *trie = arg;

        return strcmp(trie->strings->buf + val1->key_off,
                      trie->strings->buf + val2->key_off);
}

static int trie_node_add_value(struct trie *trie, struct trie_node *node,
                          const char *key, const char *value) {
        ssize_t k, v;
        struct trie_value_entry *val;

        k = strbuf_add_string(trie->strings, key, strlen(key));
        if (k < 0)
                return k;
        v = strbuf_add_string(trie->strings, value, strlen(value));
        if (v < 0)
                return v;

        if (node->values_count) {
                struct trie_value_entry search = {
                        .key_off = k,
                        .value_off = v,
                };

                val = xbsearch_r(&search, node->values, node->values_count, sizeof(struct trie_value_entry), trie_values_cmp, trie);
                if (val) {
                        /* replace existing earlier key with new value */
                        val->value_off = v;
                        return 0;
                }
        }

        /* extend array, add new entry, sort for bisection */
        val = realloc(node->values, (node->values_count + 1) * sizeof(struct trie_value_entry));
        if (!val)
                return -ENOMEM;
        trie->values_count++;
        node->values = val;
        node->values[node->values_count].key_off = k;
        node->values[node->values_count].value_off = v;
        node->values_count++;
        qsort_r(node->values, node->values_count, sizeof(struct trie_value_entry), trie_values_cmp, trie);
        return 0;
}

static int trie_insert(struct trie *trie, struct trie_node *node, const char *search,
                       const char *key, const char *value) {
        size_t i = 0;
        int err = 0;

        for (;;) {
                size_t p;
                uint8_t c;
                struct trie_node *child;

                for (p = 0; (c = trie->strings->buf[node->prefix_off + p]); p++) {
                        _cleanup_free_ char *s = NULL;
                        ssize_t off;
                        _cleanup_free_ struct trie_node *new_child = NULL;

                        if (c == search[i + p])
                                continue;

                        /* split node */
                        new_child = new0(struct trie_node, 1);
                        if (!new_child)
                                return -ENOMEM;

                        /* move values from parent to child */
                        new_child->prefix_off = node->prefix_off + p+1;
                        new_child->children = node->children;
                        new_child->children_count = node->children_count;
                        new_child->values = node->values;
                        new_child->values_count = node->values_count;

                        /* update parent; use strdup() because the source gets realloc()d */
                        s = strndup(trie->strings->buf + node->prefix_off, p);
                        if (!s)
                                return -ENOMEM;

                        off = strbuf_add_string(trie->strings, s, p);
                        if (off < 0)
                                return off;

                        node->prefix_off = off;
                        node->children = NULL;
                        node->children_count = 0;
                        node->values = NULL;
                        node->values_count = 0;
                        err = node_add_child(trie, node, new_child, c);
                        if (err < 0)
                                return err;

                        new_child = NULL; /* avoid cleanup */
                        break;
                }
                i += p;

                c = search[i];
                if (c == '\0')
                        return trie_node_add_value(trie, node, key, value);

                child = node_lookup(node, c);
                if (!child) {
                        ssize_t off;

                        /* new child */
                        child = new0(struct trie_node, 1);
                        if (!child)
                                return -ENOMEM;

                        off = strbuf_add_string(trie->strings, search + i+1, strlen(search + i+1));
                        if (off < 0) {
                                free(child);
                                return off;
                        }

                        child->prefix_off = off;
                        err = node_add_child(trie, node, child, c);
                        if (err < 0) {
                                free(child);
                                return err;
                        }

                        return trie_node_add_value(trie, child, key, value);
                }

                node = child;
                i++;
        }
}

struct trie_f {
        FILE *f;
        struct trie *trie;
        uint64_t strings_off;

        uint64_t nodes_count;
        uint64_t children_count;
        uint64_t values_count;
};

/* calculate the storage space for the nodes, children arrays, value arrays */
static void trie_store_nodes_size(struct trie_f *trie, struct trie_node *node) {
        uint64_t i;

        for (i = 0; i < node->children_count; i++)
                trie_store_nodes_size(trie, node->children[i].child);

        trie->strings_off += sizeof(struct trie_node_f);
        for (i = 0; i < node->children_count; i++)
                trie->strings_off += sizeof(struct trie_child_entry_f);
        for (i = 0; i < node->values_count; i++)
                trie->strings_off += sizeof(struct trie_value_entry_f);
}

static int64_t trie_store_nodes(struct trie_f *trie, struct trie_node *node) {
        uint64_t i;
        struct trie_node_f n = {
                .prefix_off = htole64(trie->strings_off + node->prefix_off),
                .children_count = node->children_count,
                .values_count = htole64(node->values_count),
        };
        struct trie_child_entry_f *children = NULL;
        int64_t node_off;

        if (node->children_count) {
                children = new0(struct trie_child_entry_f, node->children_count);
                if (!children)
                        return -ENOMEM;
        }

        /* post-order recursion */
        for (i = 0; i < node->children_count; i++) {
                int64_t child_off;

                child_off = trie_store_nodes(trie, node->children[i].child);
                if (child_off < 0) {
                        free(children);
                        return child_off;
                }
                children[i].c = node->children[i].c;
                children[i].child_off = htole64(child_off);
        }

        /* write node */
        node_off = ftello(trie->f);
        fwrite(&n, sizeof(struct trie_node_f), 1, trie->f);
        trie->nodes_count++;

        /* append children array */
        if (node->children_count) {
                fwrite(children, sizeof(struct trie_child_entry_f), node->children_count, trie->f);
                trie->children_count += node->children_count;
                free(children);
        }

        /* append values array */
        for (i = 0; i < node->values_count; i++) {
                struct trie_value_entry_f v = {
                        .key_off = htole64(trie->strings_off + node->values[i].key_off),
                        .value_off = htole64(trie->strings_off + node->values[i].value_off),
                };

                fwrite(&v, sizeof(struct trie_value_entry_f), 1, trie->f);
                trie->values_count++;
        }

        return node_off;
}

static int trie_store(struct trie *trie, const char *filename) {
        struct trie_f t = {
                .trie = trie,
        };
        _cleanup_free_ char *filename_tmp = NULL;
        int64_t pos;
        int64_t root_off;
        int64_t size;
        struct trie_header_f h = {
                .signature = HWDB_SIG,
                .tool_version = htole64(atoi(VERSION)),
                .header_size = htole64(sizeof(struct trie_header_f)),
                .node_size = htole64(sizeof(struct trie_node_f)),
                .child_entry_size = htole64(sizeof(struct trie_child_entry_f)),
                .value_entry_size = htole64(sizeof(struct trie_value_entry_f)),
        };
        int err;

        /* calculate size of header, nodes, children entries, value entries */
        t.strings_off = sizeof(struct trie_header_f);
        trie_store_nodes_size(&t, trie->root);

        err = fopen_temporary(filename , &t.f, &filename_tmp);
        if (err < 0)
                return err;
        fchmod(fileno(t.f), 0444);

        /* write nodes */
        err = fseeko(t.f, sizeof(struct trie_header_f), SEEK_SET);
        if (err < 0) {
                fclose(t.f);
                unlink_noerrno(filename_tmp);
                return -errno;
        }
        root_off = trie_store_nodes(&t, trie->root);
        h.nodes_root_off = htole64(root_off);
        pos = ftello(t.f);
        h.nodes_len = htole64(pos - sizeof(struct trie_header_f));

        /* write string buffer */
        fwrite(trie->strings->buf, trie->strings->len, 1, t.f);
        h.strings_len = htole64(trie->strings->len);

        /* write header */
        size = ftello(t.f);
        h.file_size = htole64(size);
        err = fseeko(t.f, 0, SEEK_SET);
        if (err < 0) {
                fclose(t.f);
                unlink_noerrno(filename_tmp);
                return -errno;
        }
        fwrite(&h, sizeof(struct trie_header_f), 1, t.f);
        err = ferror(t.f);
        if (err)
                err = -errno;
        fclose(t.f);
        if (err < 0 || rename(filename_tmp, filename) < 0) {
                unlink_noerrno(filename_tmp);
                return err < 0 ? err : -errno;
        }

        log_debug("=== trie on-disk ===");
        log_debug("size:             %8"PRIu64" bytes", size);
        log_debug("header:           %8zu bytes", sizeof(struct trie_header_f));
        log_debug("nodes:            %8"PRIu64" bytes (%8"PRIu64")",
                  t.nodes_count * sizeof(struct trie_node_f), t.nodes_count);
        log_debug("child pointers:   %8"PRIu64" bytes (%8"PRIu64")",
                  t.children_count * sizeof(struct trie_child_entry_f), t.children_count);
        log_debug("value pointers:   %8"PRIu64" bytes (%8"PRIu64")",
                  t.values_count * sizeof(struct trie_value_entry_f), t.values_count);
        log_debug("string store:     %8zu bytes", trie->strings->len);
        log_debug("strings start:    %8"PRIu64, t.strings_off);

        return 0;
}

static int insert_data(struct trie *trie, char **match_list, char *line, const char *filename) {
        char *value, **entry;

        value = strchr(line, '=');
        if (!value) {
                log_error("Error, key/value pair expected but got '%s' in '%s':", line, filename);
                return -EINVAL;
        }

        value[0] = '\0';
        value++;

        /* libudev requires properties to start with a space */
        while (isblank(line[0]) && isblank(line[1]))
                line++;

        if (line[0] == '\0' || value[0] == '\0') {
                log_error("Error, empty key or value '%s' in '%s':", line, filename);
                return -EINVAL;
        }

        STRV_FOREACH(entry, match_list)
                trie_insert(trie, trie->root, *entry, line, value);

        return 0;
}

static int import_file(struct trie *trie, const char *filename) {
        enum {
                HW_NONE,
                HW_MATCH,
                HW_DATA,
        } state = HW_NONE;
        _cleanup_fclose_ FILE *f = NULL;
        char line[LINE_MAX];
        _cleanup_strv_free_ char **match_list = NULL;
        char *match = NULL;
        int r;

        f = fopen(filename, "re");
        if (!f)
                return -errno;

        while (fgets(line, sizeof(line), f)) {
                size_t len;
                char *pos;

                /* comment line */
                if (line[0] == '#')
                        continue;

                /* strip trailing comment */
                pos = strchr(line, '#');
                if (pos)
                        pos[0] = '\0';

                /* strip trailing whitespace */
                len = strlen(line);
                while (len > 0 && isspace(line[len-1]))
                        len--;
                line[len] = '\0';

                switch (state) {
                case HW_NONE:
                        if (len == 0)
                                break;

                        if (line[0] == ' ') {
                                log_error("Error, MATCH expected but got '%s' in '%s':", line, filename);
                                break;
                        }

                        /* start of record, first match */
                        state = HW_MATCH;

                        match = strdup(line);
                        if (!match)
                                return -ENOMEM;

                        r = strv_consume(&match_list, match);
                        if (r < 0)
                                return r;

                        break;

                case HW_MATCH:
                        if (len == 0) {
                                log_error("Error, DATA expected but got empty line in '%s':", filename);
                                state = HW_NONE;
                                strv_clear(match_list);
                                break;
                        }

                        /* another match */
                        if (line[0] != ' ') {
                                match = strdup(line);
                                if (!match)
                                        return -ENOMEM;

                                r = strv_consume(&match_list, match);
                                if (r < 0)
                                        return r;

                                break;
                        }

                        /* first data */
                        state = HW_DATA;
                        insert_data(trie, match_list, line, filename);
                        break;

                case HW_DATA:
                        /* end of record */
                        if (len == 0) {
                                state = HW_NONE;
                                strv_clear(match_list);
                                break;
                        }

                        if (line[0] != ' ') {
                                log_error("Error, DATA expected but got '%s' in '%s':", line, filename);
                                state = HW_NONE;
                                strv_clear(match_list);
                                break;
                        }

                        insert_data(trie, match_list, line, filename);
                        break;
                };
        }

        return 0;
}

static int hwdb_query(char **args, unsigned n) {
        _cleanup_hwdb_unref_ sd_hwdb *hwdb = NULL;
        const char *key, *value;
        const char *modalias;
        int r;

        assert(args);
        assert(n == 2);

        modalias = args[1];

        r = sd_hwdb_new(&hwdb);
        if (r < 0)
                return r;

        SD_HWDB_FOREACH_PROPERTY(hwdb, modalias, key, value)
                printf("%s=%s\n", key, value);

        return 0;
}

static int hwdb_update(char **args, unsigned n) {
        _cleanup_free_ char *hwdb_bin = NULL;
        _cleanup_(trie_freep) struct trie *trie = NULL;
        char **files, **f;
        int r;

        trie = new0(struct trie, 1);
        if (!trie)
                return -ENOMEM;

        /* string store */
        trie->strings = strbuf_new();
        if (!trie->strings)
                return -ENOMEM;

        /* index */
        trie->root = new0(struct trie_node, 1);
        if (!trie->root)
                return -ENOMEM;

        trie->nodes_count++;

        r = conf_files_list_strv(&files, ".hwdb", arg_root, conf_file_dirs);
        if (r < 0)
                return log_error_errno(r, "failed to enumerate hwdb files: %m");

        STRV_FOREACH(f, files) {
                log_debug("reading file '%s'", *f);
                import_file(trie, *f);
        }
        strv_free(files);

        strbuf_complete(trie->strings);

        log_debug("=== trie in-memory ===");
        log_debug("nodes:            %8zu bytes (%8zu)",
                  trie->nodes_count * sizeof(struct trie_node), trie->nodes_count);
        log_debug("children arrays:  %8zu bytes (%8zu)",
                  trie->children_count * sizeof(struct trie_child_entry), trie->children_count);
        log_debug("values arrays:    %8zu bytes (%8zu)",
                  trie->values_count * sizeof(struct trie_value_entry), trie->values_count);
        log_debug("strings:          %8zu bytes",
                  trie->strings->len);
        log_debug("strings incoming: %8zu bytes (%8zu)",
                  trie->strings->in_len, trie->strings->in_count);
        log_debug("strings dedup'ed: %8zu bytes (%8zu)",
                  trie->strings->dedup_len, trie->strings->dedup_count);

        hwdb_bin = strjoin(arg_root, "/", arg_hwdb_bin_dir, "/hwdb.bin", NULL);
        if (!hwdb_bin)
                return -ENOMEM;

        mkdir_parents(hwdb_bin, 0755);
        r = trie_store(trie, hwdb_bin);
        if (r < 0)
                return log_error_errno(r, "Failure writing database %s: %m", hwdb_bin);

        return 0;
}

static void help(void) {
        printf("Usage: %s OPTIONS COMMAND\n\n"
               "Options:\n"
               "  --usr                generate in " UDEVLIBEXECDIR " instead of /etc/udev\n"
               "  -r,--root=PATH       alternative root path in the filesystem\n"
               "  -h,--help\n\n"
               "Commands:\n"
               "  update               update the hwdb database\n"
               "  query MODALIAS       query database and print result\n\n",
               program_invocation_short_name);
}

static int parse_argv(int argc, char *argv[]) {
        enum {
                ARG_USR = 0x100,
        };

        static const struct option options[] = {
                { "usr",    no_argument,       NULL, ARG_USR },
                { "root",   required_argument, NULL, 'r' },
                { "help",   no_argument,       NULL, 'h' },
                {}
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "ut:r:h", options, NULL)) >= 0) {
                switch(c) {
                case ARG_USR:
                        arg_hwdb_bin_dir = UDEVLIBEXECDIR;
                        break;
                case 'r':
                        arg_root = optarg;
                        break;
                case 'h':
                        help();
                        return 0;
                case '?':
                        return -EINVAL;
                default:
                        assert_not_reached("Unknown option");
                }
        }

        return 1;
}

static int hwdb_main(int argc, char *argv[]) {
        static const struct {
                const char *verb;
                const enum {
                        MORE,
                        LESS,
                        EQUAL,
                } argc_cmp;
                const int argc;
                int (*const dispatch)(char **args, unsigned n);
        } verbs[] = {
                { "update", EQUAL, 1, hwdb_update },
                { "query", EQUAL, 2, hwdb_query },
        };

        int left;
        unsigned i;

        assert(argc >= 0);
        assert(argv);

        left = argc - optind;

        if (left <= 0) {
                log_error("Missing command.");
                help();
                return -EINVAL;
        }

        for (i = 0; i < ELEMENTSOF(verbs); i++)
                if (streq(argv[optind], verbs[i].verb))
                        break;

        if (i >= ELEMENTSOF(verbs)) {
                log_error("Unknown command %s.", argv[optind]);
                help();
                return -EINVAL;
        }

        switch (verbs[i].argc_cmp) {
        case EQUAL:
                if (left != verbs[i].argc) {
                        log_error("Invalid number of arguments.");
                        help();
                        return -EINVAL;
                }

                break;

        case MORE:
                if (left < verbs[i].argc) {
                        log_error("Too few arguments.");
                        help();
                        return -EINVAL;
                }

                break;
        case LESS:
                if (left > verbs[i].argc) {
                        log_error("Too many arguments.");
                        help();
                        return -EINVAL;
                }

                break;
        default:
                assert_not_reached("Unknown comparison operator.");
        }

        return verbs[i].dispatch(argv + optind, left);
}

int main (int argc, char *argv[]) {
        int r;

        log_parse_environment();
        log_open();

        r = parse_argv(argc, argv);
        if (r <= 0)
                goto finish;

        r = hwdb_main(argc, argv);

finish:
        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}