diff options
Diffstat (limited to '')
| -rw-r--r-- | src/libsystemd/sd-hwdb/sd-hwdb.c | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/src/libsystemd/sd-hwdb/sd-hwdb.c b/src/libsystemd/sd-hwdb/sd-hwdb.c new file mode 100644 index 0000000..cb3c77c --- /dev/null +++ b/src/libsystemd/sd-hwdb/sd-hwdb.c @@ -0,0 +1,466 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/*** + 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 <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)) + return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), + "Failed to recognize the format of %s", + hwdb_bin_path); + + 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; + + if (!ordered_hashmap_iterate(hwdb->properties, &hwdb->properties_iterator, (void **)&entry, &k)) + return 0; + + *key = k; + *value = trie_string(hwdb, entry->value_off); + + return 1; +} |