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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2012 Kay Sievers <kay@vrfy.org>
Copyright 2008 Alan Jenkins <alan.christopher.jenkins@googlemail.com>
Copyright 2014 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <fnmatch.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.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 "refcnt.h"
#include "string-util.h"
struct sd_hwdb {
RefCount n_ref;
int refcount;
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) {
uint8_t 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 = REFCNT_INIT;
/* find hwdb.bin in hwdb_bin_paths */
NULSTR_FOREACH(hwdb_bin_path, hwdb_bin_paths) {
hwdb->f = fopen(hwdb_bin_path, "re");
if (hwdb->f)
break;
else if (errno == ENOENT)
continue;
else
return log_debug_errno(errno, "error reading %s: %m", hwdb_bin_path);
}
if (!hwdb->f) {
log_debug("hwdb.bin does not exist, please run systemd-hwdb update");
return -ENOENT;
}
if (fstat(fileno(hwdb->f), &hwdb->st) < 0 ||
(size_t)hwdb->st.st_size < offsetof(struct trie_header_f, strings_len) + 8)
return log_debug_errno(errno, "error reading %s: %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, "error mapping %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("error recognizing 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;
}
_public_ sd_hwdb *sd_hwdb_ref(sd_hwdb *hwdb) {
assert_return(hwdb, NULL);
assert_se(REFCNT_INC(hwdb->n_ref) >= 2);
return hwdb;
}
_public_ sd_hwdb *sd_hwdb_unref(sd_hwdb *hwdb) {
if (hwdb && REFCNT_DEC(hwdb->n_ref) == 0) {
if (hwdb->map)
munmap((void *)hwdb->map, hwdb->st.st_size);
safe_fclose(hwdb->f);
ordered_hashmap_free(hwdb->properties);
free(hwdb);
}
return NULL;
}
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;
}
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