src/libsystemd/sd-hwdb/sd-hwdb.c - systemd-stable - Rivoreo Source Code Repositories

 /* SPDX-License-Identifier: LGPL-2.1+ */
 /***
   Copyright © 2008 Alan Jenkins <alan.christopher.jenkins@googlemail.com>
 ***/

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

 #include "sd-hwdb.h"

 #include "alloc-util.h"
 #include "fd-util.h"
 #include "hashmap.h"
 #include "hwdb-internal.h"
 #include "hwdb-util.h"
 #include "nulstr-util.h"
 #include "string-util.h"
 #include "time-util.h"

 struct sd_hwdb {
         unsigned n_ref;

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

         OrderedHashmap *properties;
         Iterator properties_iterator;
         bool properties_modified;
 };

 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_child(sd_hwdb *hwdb, const struct trie_node_f *node, size_t idx) {
         const char *base = (const char *)node;

         base += le64toh(hwdb->head->node_size);
         base += idx * le64toh(hwdb->head->child_entry_size);
         return (const struct trie_child_entry_f *)base;
 }

 static const struct trie_value_entry_f *trie_node_value(sd_hwdb *hwdb, const struct trie_node_f *node, size_t idx) {
         const char *base = (const char *)node;

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

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

 static const char *trie_string(sd_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(sd_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, (const char *)node + le64toh(hwdb->head->node_size), 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(sd_hwdb *hwdb, const struct trie_value_entry_f *entry) {
         const char *key;
         int r;

         assert(hwdb);

         key = trie_string(hwdb, entry->key_off);

         /*
          * Silently ignore all properties which do not start with a
          * space; future extensions might use additional prefixes.
          */
         if (key[0] != ' ')
                 return 0;

         key++;

         if (le64toh(hwdb->head->value_entry_size) >= sizeof(struct trie_value_entry2_f)) {
                 const struct trie_value_entry2_f *old, *entry2;

                 entry2 = (const struct trie_value_entry2_f *)entry;
                 old = ordered_hashmap_get(hwdb->properties, key);
                 if (old) {
                         /* On duplicates, we order by filename priority and line-number.
                          *
                          * v2 of the format had 64 bits for the line number.
                          * v3 reuses top 32 bits of line_number to store the priority.
                          * We check the top bits — if they are zero we have v2 format.
                          * This means that v2 clients will print wrong line numbers with
                          * v3 data.
                          *
                          * For v3 data: we compare the priority (of the source file)
                          * and the line number.
                          *
                          * For v2 data: we rely on the fact that the filenames in the hwdb
                          * are added in the order of priority (higher later), because they
                          * are *processed* in the order of priority. So we compare the
                          * indices to determine which file had higher priority. Comparing
                          * the strings alphabetically would be useless, because those are
                          * full paths, and e.g. /usr/lib would sort after /etc, even
                          * though it has lower priority. This is not reliable because of
                          * suffix compression, but should work for the most common case of
                          * /usr/lib/udev/hwbd.d and /etc/udev/hwdb.d, and is better than
                          * not doing the comparison at all.
                          */
                         bool lower;

                         if (entry2->file_priority == 0)
                                 lower = entry2->filename_off < old->filename_off ||
                                         (entry2->filename_off == old->filename_off && entry2->line_number < old->line_number);
                         else
                                 lower = entry2->file_priority < old->file_priority ||
                                         (entry2->file_priority == old->file_priority && entry2->line_number < old->line_number);
                         if (lower)
                                 return 0;
                 }
         }

         r = ordered_hashmap_ensure_allocated(&hwdb->properties, &string_hash_ops);
         if (r < 0)
                 return r;

         r = ordered_hashmap_replace(hwdb->properties, key, (void *)entry);
         if (r < 0)
                 return r;

         hwdb->properties_modified = true;

         return 0;
 }

 static int trie_fnmatch_f(sd_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_child(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_node_value(hwdb, node, i));
                         if (err < 0)
                                 return err;
                 }

         linebuf_rem(buf, len);
         return 0;
 }

 static int trie_search_f(sd_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) {
                         char c;

                         for (; (c = trie_string(hwdb, node->prefix_off)[p]); p++) {
                                 if (IN_SET(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_node_value(hwdb, node, n));
                                 if (err < 0)
                                         return err;
                         }
                         return 0;
                 }

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

 static const char hwdb_bin_paths[] =
         "/etc/systemd/hwdb/hwdb.bin\0"
         "/etc/udev/hwdb.bin\0"
         "/usr/lib/systemd/hwdb/hwdb.bin\0"
 #if HAVE_SPLIT_USR
         "/lib/systemd/hwdb/hwdb.bin\0"
 #endif
         UDEVLIBEXECDIR "/hwdb.bin\0";

 _public_ int sd_hwdb_new(sd_hwdb **ret) {
         _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb = NULL;
         const char *hwdb_bin_path;
         const char sig[] = HWDB_SIG;

         assert_return(ret, -EINVAL);

         hwdb = new0(sd_hwdb, 1);
         if (!hwdb)
                 return -ENOMEM;

         hwdb->n_ref = 1;

         /* find hwdb.bin in hwdb_bin_paths */
         NULSTR_FOREACH(hwdb_bin_path, hwdb_bin_paths) {
                 log_debug("Trying to open \"%s\"...", hwdb_bin_path);
                 hwdb->f = fopen(hwdb_bin_path, "re");
                 if (hwdb->f)
                         break;
                 if (errno != ENOENT)
                         return log_debug_errno(errno, "Failed to open %s: %m", hwdb_bin_path);
         }

         if (!hwdb->f)
                 return log_debug_errno(SYNTHETIC_ERRNO(ENOENT),
                                        "hwdb.bin does not exist, please run 'systemd-hwdb update'");

         if (fstat(fileno(hwdb->f), &hwdb->st) < 0)
                 return log_debug_errno(errno, "Failed to stat %s: %m", hwdb_bin_path);
         if (hwdb->st.st_size < (off_t) offsetof(struct trie_header_f, strings_len) + 8)
                 return log_debug_errno(SYNTHETIC_ERRNO(EIO),
                                        "File %s is too short: %m", hwdb_bin_path);

         hwdb->map = mmap(0, hwdb->st.st_size, PROT_READ, MAP_SHARED, fileno(hwdb->f), 0);
         if (hwdb->map == MAP_FAILED)
                 return log_debug_errno(errno, "Failed to map %s: %m", hwdb_bin_path);

         if (memcmp(hwdb->map, sig, sizeof(hwdb->head->signature)) != 0 ||
             (size_t) hwdb->st.st_size != le64toh(hwdb->head->file_size)) {
                 log_debug("Failed to recognize the format of %s", hwdb_bin_path);
                 return -EINVAL;
         }

         log_debug("=== trie on-disk ===");
         log_debug("tool version:          %"PRIu64, le64toh(hwdb->head->tool_version));
         log_debug("file size:        %8"PRIi64" bytes", hwdb->st.st_size);
         log_debug("header size       %8"PRIu64" bytes", le64toh(hwdb->head->header_size));
         log_debug("strings           %8"PRIu64" bytes", le64toh(hwdb->head->strings_len));
         log_debug("nodes             %8"PRIu64" bytes", le64toh(hwdb->head->nodes_len));

         *ret = TAKE_PTR(hwdb);

         return 0;
 }

 static sd_hwdb *hwdb_free(sd_hwdb *hwdb) {
         assert(hwdb);

         if (hwdb->map)
                 munmap((void *)hwdb->map, hwdb->st.st_size);
         safe_fclose(hwdb->f);
         ordered_hashmap_free(hwdb->properties);
         return mfree(hwdb);
 }

 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_hwdb, sd_hwdb, hwdb_free)

 bool hwdb_validate(sd_hwdb *hwdb) {
         bool found = false;
         const char* p;
         struct stat st;

         if (!hwdb)
                 return false;
         if (!hwdb->f)
                 return false;

         /* if hwdb.bin doesn't exist anywhere, we need to update */
         NULSTR_FOREACH(p, hwdb_bin_paths)
                 if (stat(p, &st) >= 0) {
                         found = true;
                         break;
                 }
         if (!found)
                 return true;

         if (timespec_load(&hwdb->st.st_mtim) != timespec_load(&st.st_mtim))
                 return true;
         return false;
 }

 static int properties_prepare(sd_hwdb *hwdb, const char *modalias) {
         assert(hwdb);
         assert(modalias);

         ordered_hashmap_clear(hwdb->properties);
         hwdb->properties_modified = true;

         return trie_search_f(hwdb, modalias);
 }

 _public_ int sd_hwdb_get(sd_hwdb *hwdb, const char *modalias, const char *key, const char **_value) {
         const struct trie_value_entry_f *entry;
         int r;

         assert_return(hwdb, -EINVAL);
         assert_return(hwdb->f, -EINVAL);
         assert_return(modalias, -EINVAL);
         assert_return(_value, -EINVAL);

         r = properties_prepare(hwdb, modalias);
         if (r < 0)
                 return r;

         entry = ordered_hashmap_get(hwdb->properties, key);
         if (!entry)
                 return -ENOENT;

         *_value = trie_string(hwdb, entry->value_off);

         return 0;
 }

 _public_ int sd_hwdb_seek(sd_hwdb *hwdb, const char *modalias) {
         int r;

         assert_return(hwdb, -EINVAL);
         assert_return(hwdb->f, -EINVAL);
         assert_return(modalias, -EINVAL);

         r = properties_prepare(hwdb, modalias);
         if (r < 0)
                 return r;

         hwdb->properties_modified = false;
         hwdb->properties_iterator = ITERATOR_FIRST;

         return 0;
 }

 _public_ int sd_hwdb_enumerate(sd_hwdb *hwdb, const char **key, const char **value) {
         const struct trie_value_entry_f *entry;
         const void *k;

         assert_return(hwdb, -EINVAL);
         assert_return(key, -EINVAL);
         assert_return(value, -EINVAL);

         if (hwdb->properties_modified)
                 return -EAGAIN;

         ordered_hashmap_iterate(hwdb->properties, &hwdb->properties_iterator, (void **)&entry, &k);
         if (!k)
                 return 0;

         *key = k;
         *value = trie_string(hwdb, entry->value_off);

         return 1;
 }
	/* SPDX-License-Identifier: LGPL-2.1+ */
	/***
	Copyright © 2008 Alan Jenkins <alan.christopher.jenkins@googlemail.com>
	***/

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

	#include "sd-hwdb.h"

	#include "alloc-util.h"
	#include "fd-util.h"
	#include "hashmap.h"
	#include "hwdb-internal.h"
	#include "hwdb-util.h"
	#include "nulstr-util.h"
	#include "string-util.h"
	#include "time-util.h"

	struct sd_hwdb {
	unsigned n_ref;

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

	OrderedHashmap *properties;
	Iterator properties_iterator;
	bool properties_modified;
	};

	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_child(sd_hwdb hwdb, const struct trie_node_f *node, size_t idx) {
	const char base = (const char )node;

	base += le64toh(hwdb->head->node_size);
	base += idx * le64toh(hwdb->head->child_entry_size);
	return (const struct trie_child_entry_f *)base;
	}

	static const struct trie_value_entry_f trie_node_value(sd_hwdb hwdb, const struct trie_node_f *node, size_t idx) {
	const char base = (const char )node;

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

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

	static const char trie_string(sd_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(sd_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, (const char *)node + le64toh(hwdb->head->node_size), 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(sd_hwdb hwdb, const struct trie_value_entry_f entry) {
	const char *key;
	int r;

	assert(hwdb);

	key = trie_string(hwdb, entry->key_off);

	/*
	* Silently ignore all properties which do not start with a
	* space; future extensions might use additional prefixes.
	*/
	if (key[0] != ' ')
	return 0;

	key++;

	if (le64toh(hwdb->head->value_entry_size) >= sizeof(struct trie_value_entry2_f)) {
	const struct trie_value_entry2_f old, entry2;

	entry2 = (const struct trie_value_entry2_f *)entry;
	old = ordered_hashmap_get(hwdb->properties, key);
	if (old) {
	/* On duplicates, we order by filename priority and line-number.
	*
	* v2 of the format had 64 bits for the line number.
	* v3 reuses top 32 bits of line_number to store the priority.
	* We check the top bits — if they are zero we have v2 format.
	* This means that v2 clients will print wrong line numbers with
	* v3 data.
	*
	* For v3 data: we compare the priority (of the source file)
	* and the line number.
	*
	* For v2 data: we rely on the fact that the filenames in the hwdb
	* are added in the order of priority (higher later), because they
	* are processed in the order of priority. So we compare the
	* indices to determine which file had higher priority. Comparing
	* the strings alphabetically would be useless, because those are
	* full paths, and e.g. /usr/lib would sort after /etc, even
	* though it has lower priority. This is not reliable because of
	* suffix compression, but should work for the most common case of
	* /usr/lib/udev/hwbd.d and /etc/udev/hwdb.d, and is better than
	* not doing the comparison at all.
	*/
	bool lower;

	if (entry2->file_priority == 0)
	lower = entry2->filename_off < old->filename_off \|\|
	(entry2->filename_off == old->filename_off && entry2->line_number < old->line_number);
	else
	lower = entry2->file_priority < old->file_priority \|\|
	(entry2->file_priority == old->file_priority && entry2->line_number < old->line_number);
	if (lower)
	return 0;
	}
	}

	r = ordered_hashmap_ensure_allocated(&hwdb->properties, &string_hash_ops);
	if (r < 0)
	return r;

	r = ordered_hashmap_replace(hwdb->properties, key, (void *)entry);
	if (r < 0)
	return r;

	hwdb->properties_modified = true;

	return 0;
	}

	static int trie_fnmatch_f(sd_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_child(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_node_value(hwdb, node, i));
	if (err < 0)
	return err;
	}

	linebuf_rem(buf, len);
	return 0;
	}

	static int trie_search_f(sd_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) {
	char c;

	for (; (c = trie_string(hwdb, node->prefix_off)[p]); p++) {
	if (IN_SET(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_node_value(hwdb, node, n));
	if (err < 0)
	return err;
	}
	return 0;
	}

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

	static const char hwdb_bin_paths[] =
	"/etc/systemd/hwdb/hwdb.bin\0"
	"/etc/udev/hwdb.bin\0"
	"/usr/lib/systemd/hwdb/hwdb.bin\0"
	#if HAVE_SPLIT_USR
	"/lib/systemd/hwdb/hwdb.bin\0"
	#endif
	UDEVLIBEXECDIR "/hwdb.bin\0";

	_public_ int sd_hwdb_new(sd_hwdb **ret) {
	_cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb = NULL;
	const char *hwdb_bin_path;
	const char sig[] = HWDB_SIG;

	assert_return(ret, -EINVAL);

	hwdb = new0(sd_hwdb, 1);
	if (!hwdb)
	return -ENOMEM;

	hwdb->n_ref = 1;

	/* find hwdb.bin in hwdb_bin_paths */
	NULSTR_FOREACH(hwdb_bin_path, hwdb_bin_paths) {
	log_debug("Trying to open \"%s\"...", hwdb_bin_path);
	hwdb->f = fopen(hwdb_bin_path, "re");
	if (hwdb->f)
	break;
	if (errno != ENOENT)
	return log_debug_errno(errno, "Failed to open %s: %m", hwdb_bin_path);
	}

	if (!hwdb->f)
	return log_debug_errno(SYNTHETIC_ERRNO(ENOENT),
	"hwdb.bin does not exist, please run 'systemd-hwdb update'");

	if (fstat(fileno(hwdb->f), &hwdb->st) < 0)
	return log_debug_errno(errno, "Failed to stat %s: %m", hwdb_bin_path);
	if (hwdb->st.st_size < (off_t) offsetof(struct trie_header_f, strings_len) + 8)
	return log_debug_errno(SYNTHETIC_ERRNO(EIO),
	"File %s is too short: %m", hwdb_bin_path);

	hwdb->map = mmap(0, hwdb->st.st_size, PROT_READ, MAP_SHARED, fileno(hwdb->f), 0);
	if (hwdb->map == MAP_FAILED)
	return log_debug_errno(errno, "Failed to map %s: %m", hwdb_bin_path);

	if (memcmp(hwdb->map, sig, sizeof(hwdb->head->signature)) != 0 \|\|
	(size_t) hwdb->st.st_size != le64toh(hwdb->head->file_size)) {
	log_debug("Failed to recognize the format of %s", hwdb_bin_path);
	return -EINVAL;
	}

	log_debug("=== trie on-disk ===");
	log_debug("tool version: %"PRIu64, le64toh(hwdb->head->tool_version));
	log_debug("file size: %8"PRIi64" bytes", hwdb->st.st_size);
	log_debug("header size %8"PRIu64" bytes", le64toh(hwdb->head->header_size));
	log_debug("strings %8"PRIu64" bytes", le64toh(hwdb->head->strings_len));
	log_debug("nodes %8"PRIu64" bytes", le64toh(hwdb->head->nodes_len));

	*ret = TAKE_PTR(hwdb);

	return 0;
	}

	static sd_hwdb hwdb_free(sd_hwdb hwdb) {
	assert(hwdb);

	if (hwdb->map)
	munmap((void *)hwdb->map, hwdb->st.st_size);
	safe_fclose(hwdb->f);
	ordered_hashmap_free(hwdb->properties);
	return mfree(hwdb);
	}

	DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_hwdb, sd_hwdb, hwdb_free)

	bool hwdb_validate(sd_hwdb *hwdb) {
	bool found = false;
	const char* p;
	struct stat st;

	if (!hwdb)
	return false;
	if (!hwdb->f)
	return false;

	/* if hwdb.bin doesn't exist anywhere, we need to update */
	NULSTR_FOREACH(p, hwdb_bin_paths)
	if (stat(p, &st) >= 0) {
	found = true;
	break;
	}
	if (!found)
	return true;

	if (timespec_load(&hwdb->st.st_mtim) != timespec_load(&st.st_mtim))
	return true;
	return false;
	}

	static int properties_prepare(sd_hwdb hwdb, const char modalias) {
	assert(hwdb);
	assert(modalias);

	ordered_hashmap_clear(hwdb->properties);
	hwdb->properties_modified = true;

	return trie_search_f(hwdb, modalias);
	}

	_public_ int sd_hwdb_get(sd_hwdb hwdb, const char modalias, const char key, const char *_value) {
	const struct trie_value_entry_f *entry;
	int r;

	assert_return(hwdb, -EINVAL);
	assert_return(hwdb->f, -EINVAL);
	assert_return(modalias, -EINVAL);
	assert_return(_value, -EINVAL);

	r = properties_prepare(hwdb, modalias);
	if (r < 0)
	return r;

	entry = ordered_hashmap_get(hwdb->properties, key);
	if (!entry)
	return -ENOENT;

	*_value = trie_string(hwdb, entry->value_off);

	return 0;
	}

	_public_ int sd_hwdb_seek(sd_hwdb hwdb, const char modalias) {
	int r;

	assert_return(hwdb, -EINVAL);
	assert_return(hwdb->f, -EINVAL);
	assert_return(modalias, -EINVAL);

	r = properties_prepare(hwdb, modalias);
	if (r < 0)
	return r;

	hwdb->properties_modified = false;
	hwdb->properties_iterator = ITERATOR_FIRST;

	return 0;
	}

	_public_ int sd_hwdb_enumerate(sd_hwdb hwdb, const char key, const char *value) {
	const struct trie_value_entry_f *entry;
	const void *k;

	assert_return(hwdb, -EINVAL);
	assert_return(key, -EINVAL);
	assert_return(value, -EINVAL);

	if (hwdb->properties_modified)
	return -EAGAIN;

	ordered_hashmap_iterate(hwdb->properties, &hwdb->properties_iterator, (void **)&entry, &k);
	if (!k)
	return 0;

	*key = k;
	*value = trie_string(hwdb, entry->value_off);

	return 1;
	}