src/shared/hwdb-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <ctype.h>
   4 #include <stdio.h>
   5 #include <sys/stat.h>
   6
   7 #include "alloc-util.h"
   8 #include "conf-files.h"
   9 #include "fd-util.h"
  10 #include "fileio.h"
  11 #include "fs-util.h"
  12 #include "hwdb-internal.h"
  13 #include "hwdb-util.h"
  14 #include "label.h"
  15 #include "mkdir-label.h"
  16 #include "nulstr-util.h"
  17 #include "path-util.h"
  18 #include "sort-util.h"
  19 #include "strbuf.h"
  20 #include "string-util.h"
  21 #include "strv.h"
  22 #include "tmpfile-util.h"
  23
  24 static const char* const conf_file_dirs[] = {
  25         "/etc/udev/hwdb.d",
  26         UDEVLIBEXECDIR "/hwdb.d",
  27         NULL
  28 };
  29
  30 /*
  31  * Generic udev properties, key-value database based on modalias strings.
  32  * Uses a Patricia/radix trie to index all matches for efficient lookup.
  33  */
  34
  35 /* in-memory trie objects */
  36 struct trie {
  37         struct trie_node *root;
  38         struct strbuf *strings;
  39
  40         size_t nodes_count;
  41         size_t children_count;
  42         size_t values_count;
  43 };
  44
  45 struct trie_node {
  46         /* prefix, common part for all children of this node */
  47         size_t prefix_off;
  48
  49         /* sorted array of pointers to children nodes */
  50         struct trie_child_entry *children;
  51         uint8_t children_count;
  52
  53         /* sorted array of key-value pairs */
  54         struct trie_value_entry *values;
  55         size_t values_count;
  56 };
  57
  58 /* children array item with char (0-255) index */
  59 struct trie_child_entry {
  60         uint8_t c;
  61         struct trie_node *child;
  62 };
  63
  64 /* value array item with key-value pairs */
  65 struct trie_value_entry {
  66         size_t key_off;
  67         size_t value_off;
  68         size_t filename_off;
  69         uint32_t line_number;
  70         uint16_t file_priority;
  71 };
  72
  73 static int trie_children_cmp(const struct trie_child_entry *a, const struct trie_child_entry *b) {
  74         return CMP(a->c, b->c);
  75 }
  76
  77 static int node_add_child(struct trie *trie, struct trie_node *node, struct trie_node *node_child, uint8_t c) {
  78         struct trie_child_entry *child;
  79
  80         /* extend array, add new entry, sort for bisection */
  81         child = reallocarray(node->children, node->children_count + 1, sizeof(struct trie_child_entry));
  82         if (!child)
  83                 return -ENOMEM;
  84
  85         node->children = child;
  86         trie->children_count++;
  87         node->children[node->children_count].c = c;
  88         node->children[node->children_count].child = node_child;
  89         node->children_count++;
  90         typesafe_qsort(node->children, node->children_count, trie_children_cmp);
  91         trie->nodes_count++;
  92
  93         return 0;
  94 }
  95
  96 static struct trie_node *node_lookup(const struct trie_node *node, uint8_t c) {
  97         struct trie_child_entry *child;
  98         struct trie_child_entry search;
  99
 100         search.c = c;
 101         child = typesafe_bsearch(&search, node->children, node->children_count, trie_children_cmp);
 102         if (child)
 103                 return child->child;
 104         return NULL;
 105 }
 106
 107 static void trie_node_cleanup(struct trie_node *node) {
 108         if (!node)
 109                 return;
 110
 111         for (size_t i = 0; i < node->children_count; i++)
 112                 trie_node_cleanup(node->children[i].child);
 113         free(node->children);
 114         free(node->values);
 115         free(node);
 116 }
 117
 118 static struct trie* trie_free(struct trie *trie) {
 119         if (!trie)
 120                 return NULL;
 121
 122         trie_node_cleanup(trie->root);
 123         strbuf_free(trie->strings);
 124         return mfree(trie);
 125 }
 126
 127 DEFINE_TRIVIAL_CLEANUP_FUNC(struct trie*, trie_free);
 128
 129 static int trie_values_cmp(const struct trie_value_entry *a, const struct trie_value_entry *b, struct trie *trie) {
 130         return strcmp(trie->strings->buf + a->key_off,
 131                       trie->strings->buf + b->key_off);
 132 }
 133
 134 static int trie_node_add_value(struct trie *trie, struct trie_node *node,
 135                                const char *key, const char *value,
 136                                const char *filename, uint16_t file_priority, uint32_t line_number, bool compat) {
 137         ssize_t k, v, fn = 0;
 138         struct trie_value_entry *val;
 139
 140         k = strbuf_add_string(trie->strings, key, strlen(key));
 141         if (k < 0)
 142                 return k;
 143         v = strbuf_add_string(trie->strings, value, strlen(value));
 144         if (v < 0)
 145                 return v;
 146
 147         if (!compat) {
 148                 fn = strbuf_add_string(trie->strings, filename, strlen(filename));
 149                 if (fn < 0)
 150                         return fn;
 151         }
 152
 153         if (node->values_count) {
 154                 struct trie_value_entry search = {
 155                         .key_off = k,
 156                         .value_off = v,
 157                 };
 158
 159                 val = typesafe_bsearch_r(&search, node->values, node->values_count, trie_values_cmp, trie);
 160                 if (val) {
 161                         /* At this point we have 2 identical properties on the same match-string.
 162                          * Since we process files in order, we just replace the previous value. */
 163                         val->value_off = v;
 164                         val->filename_off = fn;
 165                         val->file_priority = file_priority;
 166                         val->line_number = line_number;
 167                         return 0;
 168                 }
 169         }
 170
 171         /* extend array, add new entry, sort for bisection */
 172         val = reallocarray(node->values, node->values_count + 1, sizeof(struct trie_value_entry));
 173         if (!val)
 174                 return -ENOMEM;
 175         trie->values_count++;
 176         node->values = val;
 177         node->values[node->values_count] = (struct trie_value_entry) {
 178                 .key_off = k,
 179                 .value_off = v,
 180                 .filename_off = fn,
 181                 .file_priority = file_priority,
 182                 .line_number = line_number,
 183         };
 184         node->values_count++;
 185         typesafe_qsort_r(node->values, node->values_count, trie_values_cmp, trie);
 186         return 0;
 187 }
 188
 189 static int trie_insert(struct trie *trie, struct trie_node *node, const char *search,
 190                        const char *key, const char *value,
 191                        const char *filename, uint16_t file_priority, uint32_t line_number, bool compat) {
 192         int r = 0;
 193
 194         for (size_t i = 0;; i++) {
 195                 size_t p;
 196                 uint8_t c;
 197                 struct trie_node *child;
 198
 199                 for (p = 0; (c = trie->strings->buf[node->prefix_off + p]); p++) {
 200                         _cleanup_free_ struct trie_node *new_child = NULL;
 201                         _cleanup_free_ char *s = NULL;
 202                         ssize_t off;
 203
 204                         if (c == search[i + p])
 205                                 continue;
 206
 207                         /* split node */
 208                         new_child = new(struct trie_node, 1);
 209                         if (!new_child)
 210                                 return -ENOMEM;
 211
 212                         /* move values from parent to child */
 213                         *new_child = (struct trie_node) {
 214                                 .prefix_off = node->prefix_off + p+1,
 215                                 .children = node->children,
 216                                 .children_count = node->children_count,
 217                                 .values = node->values,
 218                                 .values_count = node->values_count,
 219                         };
 220
 221                         /* update parent; use strdup() because the source gets realloc()d */
 222                         s = strndup(trie->strings->buf + node->prefix_off, p);
 223                         if (!s)
 224                                 return -ENOMEM;
 225
 226                         off = strbuf_add_string(trie->strings, s, p);
 227                         if (off < 0)
 228                                 return off;
 229
 230                         *node = (struct trie_node) {
 231                                 .prefix_off = off,
 232                         };
 233                         r = node_add_child(trie, node, new_child, c);
 234                         if (r < 0)
 235                                 return r;
 236
 237                         new_child = NULL; /* avoid cleanup */
 238                         break;
 239                 }
 240                 i += p;
 241
 242                 c = search[i];
 243                 if (c == '\0')
 244                         return trie_node_add_value(trie, node, key, value, filename, file_priority, line_number, compat);
 245
 246                 child = node_lookup(node, c);
 247                 if (!child) {
 248                         _cleanup_free_ struct trie_node *new_child = NULL;
 249                         ssize_t off;
 250
 251                         /* new child */
 252                         new_child = new(struct trie_node, 1);
 253                         if (!new_child)
 254                                 return -ENOMEM;
 255
 256                         off = strbuf_add_string(trie->strings, search + i+1, strlen(search + i+1));
 257                         if (off < 0)
 258                                 return off;
 259
 260                         *new_child = (struct trie_node) {
 261                                 .prefix_off = off,
 262                         };
 263
 264                         r = node_add_child(trie, node, new_child, c);
 265                         if (r < 0)
 266                                 return r;
 267
 268                         child = TAKE_PTR(new_child);
 269                         return trie_node_add_value(trie, child, key, value, filename, file_priority, line_number, compat);
 270                 }
 271
 272                 node = child;
 273         }
 274 }
 275
 276 struct trie_f {
 277         FILE *f;
 278         struct trie *trie;
 279         uint64_t strings_off;
 280
 281         uint64_t nodes_count;
 282         uint64_t children_count;
 283         uint64_t values_count;
 284 };
 285
 286 /* calculate the storage space for the nodes, children arrays, value arrays */
 287 static void trie_store_nodes_size(struct trie_f *trie, struct trie_node *node, bool compat) {
 288         for (uint64_t i = 0; i < node->children_count; i++)
 289                 trie_store_nodes_size(trie, node->children[i].child, compat);
 290
 291         trie->strings_off += sizeof(struct trie_node_f);
 292         for (uint64_t i = 0; i < node->children_count; i++)
 293                 trie->strings_off += sizeof(struct trie_child_entry_f);
 294         for (uint64_t i = 0; i < node->values_count; i++)
 295                 trie->strings_off += compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f);
 296 }
 297
 298 static int64_t trie_store_nodes(struct trie_f *trie, struct trie_node *node, bool compat) {
 299         struct trie_node_f n = {
 300                 .prefix_off = htole64(trie->strings_off + node->prefix_off),
 301                 .children_count = node->children_count,
 302                 .values_count = htole64(node->values_count),
 303         };
 304         _cleanup_free_ struct trie_child_entry_f *children = NULL;
 305         int64_t node_off;
 306
 307         if (node->children_count) {
 308                 children = new(struct trie_child_entry_f, node->children_count);
 309                 if (!children)
 310                         return -ENOMEM;
 311         }
 312
 313         /* post-order recursion */
 314         for (uint64_t i = 0; i < node->children_count; i++) {
 315                 int64_t child_off;
 316
 317                 child_off = trie_store_nodes(trie, node->children[i].child, compat);
 318                 if (child_off < 0)
 319                         return child_off;
 320
 321                 children[i] = (struct trie_child_entry_f) {
 322                         .c = node->children[i].c,
 323                         .child_off = htole64(child_off),
 324                 };
 325         }
 326
 327         /* write node */
 328         node_off = ftello(trie->f);
 329         fwrite(&n, sizeof(struct trie_node_f), 1, trie->f);
 330         trie->nodes_count++;
 331
 332         /* append children array */
 333         if (node->children_count) {
 334                 fwrite(children, sizeof(struct trie_child_entry_f), node->children_count, trie->f);
 335                 trie->children_count += node->children_count;
 336         }
 337
 338         /* append values array */
 339         for (uint64_t i = 0; i < node->values_count; i++) {
 340                 struct trie_value_entry2_f v = {
 341                         .key_off = htole64(trie->strings_off + node->values[i].key_off),
 342                         .value_off = htole64(trie->strings_off + node->values[i].value_off),
 343                         .filename_off = htole64(trie->strings_off + node->values[i].filename_off),
 344                         .line_number = htole32(node->values[i].line_number),
 345                         .file_priority = htole16(node->values[i].file_priority),
 346                 };
 347
 348                 fwrite(&v, compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f), 1, trie->f);
 349         }
 350         trie->values_count += node->values_count;
 351
 352         return node_off;
 353 }
 354
 355 static int trie_store(struct trie *trie, const char *filename, bool compat) {
 356         struct trie_f t = {
 357                 .trie = trie,
 358         };
 359         _cleanup_free_ char *filename_tmp = NULL;
 360         int64_t pos;
 361         int64_t root_off;
 362         int64_t size;
 363         struct trie_header_f h = {
 364                 .signature = HWDB_SIG,
 365                 .tool_version = htole64(PROJECT_VERSION),
 366                 .header_size = htole64(sizeof(struct trie_header_f)),
 367                 .node_size = htole64(sizeof(struct trie_node_f)),
 368                 .child_entry_size = htole64(sizeof(struct trie_child_entry_f)),
 369                 .value_entry_size = htole64(compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f)),
 370         };
 371         int r;
 372
 373         /* calculate size of header, nodes, children entries, value entries */
 374         t.strings_off = sizeof(struct trie_header_f);
 375         trie_store_nodes_size(&t, trie->root, compat);
 376
 377         r = fopen_temporary(filename, &t.f, &filename_tmp);
 378         if (r < 0)
 379                 return r;
 380         (void) fchmod(fileno(t.f), 0444);
 381
 382         /* write nodes */
 383         if (fseeko(t.f, sizeof(struct trie_header_f), SEEK_SET) < 0)
 384                 goto error_fclose;
 385
 386         root_off = trie_store_nodes(&t, trie->root, compat);
 387         h.nodes_root_off = htole64(root_off);
 388         pos = ftello(t.f);
 389         h.nodes_len = htole64(pos - sizeof(struct trie_header_f));
 390
 391         /* write string buffer */
 392         fwrite(trie->strings->buf, trie->strings->len, 1, t.f);
 393         h.strings_len = htole64(trie->strings->len);
 394
 395         /* write header */
 396         size = ftello(t.f);
 397         h.file_size = htole64(size);
 398         if (fseeko(t.f, 0, SEEK_SET) < 0)
 399                 goto error_fclose;
 400         fwrite(&h, sizeof(struct trie_header_f), 1, t.f);
 401
 402         if (ferror(t.f))
 403                 goto error_fclose;
 404         if (fflush(t.f) < 0)
 405                 goto error_fclose;
 406         if (fsync(fileno(t.f)) < 0)
 407                 goto error_fclose;
 408         if (rename(filename_tmp, filename) < 0)
 409                 goto error_fclose;
 410
 411         /* write succeeded */
 412         fclose(t.f);
 413
 414         log_debug("=== trie on-disk ===");
 415         log_debug("size:             %8"PRIi64" bytes", size);
 416         log_debug("header:           %8zu bytes", sizeof(struct trie_header_f));
 417         log_debug("nodes:            %8"PRIu64" bytes (%8"PRIu64")",
 418                   t.nodes_count * sizeof(struct trie_node_f), t.nodes_count);
 419         log_debug("child pointers:   %8"PRIu64" bytes (%8"PRIu64")",
 420                   t.children_count * sizeof(struct trie_child_entry_f), t.children_count);
 421         log_debug("value pointers:   %8"PRIu64" bytes (%8"PRIu64")",
 422                   t.values_count * (compat ? sizeof(struct trie_value_entry_f) : sizeof(struct trie_value_entry2_f)), t.values_count);
 423         log_debug("string store:     %8zu bytes", trie->strings->len);
 424         log_debug("strings start:    %8"PRIu64, t.strings_off);
 425         return 0;
 426
 427  error_fclose:
 428         r = -errno;
 429         fclose(t.f);
 430         (void) unlink(filename_tmp);
 431         return r;
 432 }
 433
 434 static int insert_data(struct trie *trie, char **match_list, char *line, const char *filename,
 435                        uint16_t file_priority, uint32_t line_number, bool compat) {
 436         char *value;
 437
 438         assert(line[0] == ' ');
 439
 440         value = strchr(line, '=');
 441         if (!value)
 442                 return log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
 443                                   "Key-value pair expected but got \"%s\", ignoring.", line);
 444
 445         value[0] = '\0';
 446         value++;
 447
 448         /* Replace multiple leading spaces by a single space */
 449         while (isblank(line[0]) && isblank(line[1]))
 450                 line++;
 451
 452         if (isempty(line + 1))
 453                 return log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
 454                                   "Empty key in \"%s=%s\", ignoring.",
 455                                   line, value);
 456
 457         STRV_FOREACH(entry, match_list)
 458                 trie_insert(trie, trie->root, *entry, line, value, filename, file_priority, line_number, compat);
 459
 460         return 0;
 461 }
 462
 463 static int import_file(struct trie *trie, const char *filename, uint16_t file_priority, bool compat) {
 464         enum {
 465                 HW_NONE,
 466                 HW_MATCH,
 467                 HW_DATA,
 468         } state = HW_NONE;
 469         _cleanup_fclose_ FILE *f = NULL;
 470         _cleanup_strv_free_ char **match_list = NULL;
 471         uint32_t line_number = 0;
 472         int r, err;
 473
 474         f = fopen(filename, "re");
 475         if (!f)
 476                 return -errno;
 477
 478         for (;;) {
 479                 _cleanup_free_ char *line = NULL;
 480                 size_t len;
 481                 char *pos;
 482
 483                 r = read_line_full(f, LONG_LINE_MAX, READ_LINE_NOT_A_TTY, &line);
 484                 if (r < 0)
 485                         return r;
 486                 if (r == 0)
 487                         break;
 488
 489                 line_number ++;
 490
 491                 /* comment line */
 492                 if (line[0] == '#')
 493                         continue;
 494
 495                 /* strip trailing comment */
 496                 pos = strchr(line, '#');
 497                 if (pos)
 498                         pos[0] = '\0';
 499
 500                 /* strip trailing whitespace */
 501                 len = strlen(line);
 502                 while (len > 0 && isspace(line[len-1]))
 503                         len--;
 504                 line[len] = '\0';
 505
 506                 switch (state) {
 507                 case HW_NONE:
 508                         if (len == 0)
 509                                 break;
 510
 511                         if (line[0] == ' ') {
 512                                 r = log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
 513                                                "Match expected but got indented property \"%s\", ignoring line.", line);
 514                                 break;
 515                         }
 516
 517                         /* start of record, first match */
 518                         state = HW_MATCH;
 519
 520                         err = strv_extend(&match_list, line);
 521                         if (err < 0)
 522                                 return err;
 523
 524                         break;
 525
 526                 case HW_MATCH:
 527                         if (len == 0) {
 528                                 r = log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
 529                                                "Property expected, ignoring record with no properties.");
 530                                 state = HW_NONE;
 531                                 match_list = strv_free(match_list);
 532                                 break;
 533                         }
 534
 535                         if (line[0] != ' ') {
 536                                 /* another match */
 537                                 err = strv_extend(&match_list, line);
 538                                 if (err < 0)
 539                                         return err;
 540
 541                                 break;
 542                         }
 543
 544                         /* first data */
 545                         state = HW_DATA;
 546                         err = insert_data(trie, match_list, line, filename, file_priority, line_number, compat);
 547                         if (err < 0)
 548                                 r = err;
 549                         break;
 550
 551                 case HW_DATA:
 552                         if (len == 0) {
 553                                 /* end of record */
 554                                 state = HW_NONE;
 555                                 match_list = strv_free(match_list);
 556                                 break;
 557                         }
 558
 559                         if (line[0] != ' ') {
 560                                 r = log_syntax(NULL, LOG_WARNING, filename, line_number, SYNTHETIC_ERRNO(EINVAL),
 561                                                "Property or empty line expected, got \"%s\", ignoring record.", line);
 562                                 state = HW_NONE;
 563                                 match_list = strv_free(match_list);
 564                                 break;
 565                         }
 566
 567                         err = insert_data(trie, match_list, line, filename, file_priority, line_number, compat);
 568                         if (err < 0)
 569                                 r = err;
 570                         break;
 571                 };
 572         }
 573
 574         if (state == HW_MATCH)
 575                 log_syntax(NULL, LOG_WARNING, filename, line_number, 0,
 576                            "Property expected, ignoring record with no properties.");
 577
 578         return r;
 579 }
 580
 581 int hwdb_update(const char *root, const char *hwdb_bin_dir, bool strict, bool compat) {
 582         _cleanup_free_ char *hwdb_bin = NULL;
 583         _cleanup_(trie_freep) struct trie *trie = NULL;
 584         _cleanup_strv_free_ char **files = NULL;
 585         uint16_t file_priority = 1;
 586         int r = 0, err;
 587
 588         /* The argument 'compat' controls the format version of database. If false, then hwdb.bin will be
 589          * created with additional information such that priority, line number, and filename of database
 590          * source. If true, then hwdb.bin will be created without the information. systemd-hwdb command
 591          * should set the argument false, and 'udevadm hwdb' command should set it true. */
 592
 593         trie = new0(struct trie, 1);
 594         if (!trie)
 595                 return -ENOMEM;
 596
 597         /* string store */
 598         trie->strings = strbuf_new();
 599         if (!trie->strings)
 600                 return -ENOMEM;
 601
 602         /* index */
 603         trie->root = new0(struct trie_node, 1);
 604         if (!trie->root)
 605                 return -ENOMEM;
 606
 607         trie->nodes_count++;
 608
 609         err = conf_files_list_strv(&files, ".hwdb", root, 0, conf_file_dirs);
 610         if (err < 0)
 611                 return log_error_errno(err, "Failed to enumerate hwdb files: %m");
 612
 613         STRV_FOREACH(f, files) {
 614                 log_debug("Reading file \"%s\"", *f);
 615                 err = import_file(trie, *f, file_priority++, compat);
 616                 if (err < 0 && strict)
 617                         r = err;
 618         }
 619
 620         strbuf_complete(trie->strings);
 621
 622         log_debug("=== trie in-memory ===");
 623         log_debug("nodes:            %8zu bytes (%8zu)",
 624                   trie->nodes_count * sizeof(struct trie_node), trie->nodes_count);
 625         log_debug("children arrays:  %8zu bytes (%8zu)",
 626                   trie->children_count * sizeof(struct trie_child_entry), trie->children_count);
 627         log_debug("values arrays:    %8zu bytes (%8zu)",
 628                   trie->values_count * sizeof(struct trie_value_entry), trie->values_count);
 629         log_debug("strings:          %8zu bytes",
 630                   trie->strings->len);
 631         log_debug("strings incoming: %8zu bytes (%8zu)",
 632                   trie->strings->in_len, trie->strings->in_count);
 633         log_debug("strings dedup'ed: %8zu bytes (%8zu)",
 634                   trie->strings->dedup_len, trie->strings->dedup_count);
 635
 636         hwdb_bin = path_join(root, hwdb_bin_dir ?: "/etc/udev", "hwdb.bin");
 637         if (!hwdb_bin)
 638                 return -ENOMEM;
 639
 640         (void) mkdir_parents_label(hwdb_bin, 0755);
 641         err = trie_store(trie, hwdb_bin, compat);
 642         if (err < 0)
 643                 return log_error_errno(err, "Failed to write database %s: %m", hwdb_bin);
 644
 645         err = label_fix(hwdb_bin, 0);
 646         if (err < 0)
 647                 return err;
 648
 649         return r;
 650 }
 651
 652 int hwdb_query(const char *modalias, const char *root) {
 653         _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb = NULL;
 654         const char *key, *value;
 655         int r;
 656
 657         assert(modalias);
 658
 659         if (!isempty(root))
 660                 NULSTR_FOREACH(p, hwdb_bin_paths) {
 661                         _cleanup_free_ char *hwdb_bin = NULL;
 662
 663                         hwdb_bin = path_join(root, p);
 664                         if (!hwdb_bin)
 665                                 return -ENOMEM;
 666
 667                         r = sd_hwdb_new_from_path(hwdb_bin, &hwdb);
 668                         if (r >= 0)
 669                                 break;
 670                 }
 671         else
 672                 r = sd_hwdb_new(&hwdb);
 673         if (r < 0)
 674                 return r;
 675
 676         SD_HWDB_FOREACH_PROPERTY(hwdb, modalias, key, value)
 677                 printf("%s=%s\n", key, value);
 678
 679         return 0;
 680 }
 681
 682 bool hwdb_should_reload(sd_hwdb *hwdb) {
 683         bool found = false;
 684         struct stat st;
 685
 686         if (!hwdb)
 687                 return false;
 688         if (!hwdb->f)
 689                 return false;
 690
 691         /* if hwdb.bin doesn't exist anywhere, we need to update */
 692         NULSTR_FOREACH(p, hwdb_bin_paths)
 693                 if (stat(p, &st) >= 0) {
 694                         found = true;
 695                         break;
 696                 }
 697         if (!found)
 698                 return true;
 699
 700         if (timespec_load(&hwdb->st.st_mtim) != timespec_load(&st.st_mtim))
 701                 return true;
 702         return false;
 703 }