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sd-hwdb: fix child/value offset calculation

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It is not legal to use hard-coded types to calculate offsets. We must
always use the offsets of the hwdb header to calculate those. Otherwise,
we will break horribly if run on hwdb files written by other
implementations or written with future extensions.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
This commit is contained in:
David Herrmann 2016-09-21 14:56:04 +02:00
parent 21dc02277d
commit 8bf9763656
1 changed files with 14 additions and 9 deletions
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23
src/libsystemd/sd-hwdb/sd-hwdb.c
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@ -97,15 +97,20 @@ static void linebuf_rem_char(struct linebuf *buf) {
linebuf_rem(buf, 1);
}
static const struct trie_child_entry_f *trie_node_children(sd_hwdb *hwdb, const struct trie_node_f *node) {
return (const struct trie_child_entry_f *)((const char *)node + le64toh(hwdb->head->node_size));
static const struct trie_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_values(sd_hwdb *hwdb, const struct trie_node_f *node) {
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;
}
@ -129,7 +134,7 @@ static const struct trie_node_f *node_lookup_f(sd_hwdb *hwdb, const struct trie_
struct trie_child_entry_f search;
search.c = c;
child = bsearch(&search, trie_node_children(hwdb, node), node->children_count,
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);
@ -177,7 +182,7 @@ static int trie_fnmatch_f(sd_hwdb *hwdb, const struct trie_node_f *node, size_t
linebuf_add(buf, prefix + p, len);
for (i = 0; i < node->children_count; i++) {
const struct trie_child_entry_f *child = &trie_node_children(hwdb, node)[i];
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);
@ -188,8 +193,8 @@ static int trie_fnmatch_f(sd_hwdb *hwdb, const struct trie_node_f *node, size_t
if (le64toh(node->values_count) && fnmatch(linebuf_get(buf), search, 0) == 0)
for (i = 0; i < le64toh(node->values_count); i++) {
err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_values(hwdb, node)[i].key_off),
trie_string(hwdb, trie_node_values(hwdb, node)[i].value_off));
err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_value(hwdb, node, i)->key_off),
trie_string(hwdb, trie_node_value(hwdb, node, i)->value_off));
if (err < 0)
return err;
}
@ -254,8 +259,8 @@ static int trie_search_f(sd_hwdb *hwdb, const char *search) {
size_t n;
for (n = 0; n < le64toh(node->values_count); n++) {
err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_values(hwdb, node)[n].key_off),
trie_string(hwdb, trie_node_values(hwdb, node)[n].value_off));
err = hwdb_add_property(hwdb, trie_string(hwdb, trie_node_value(hwdb, node, n)->key_off),
trie_string(hwdb, trie_node_value(hwdb, node, n)->value_off));
if (err < 0)
return err;
}