[systemd-devel] [PATCH 1/2] libsystemd: add sd-hwdb library
Tom Gundersen
teg at jklm.no
Wed Dec 3 13:11:40 PST 2014
This is libudev-hwdb, but decoupled from libudev and in the libsystemd style.
The core code is unchanged, apart from the following minor changes:
- hwdb.bin located in /**/systemd/hwdb/ take preference over the ones located
in /**/udev/
- properties are stored internally in an OrderedHashmap, rather than a
linked list.
- a new API call allows individual properties to be queried directly, rather
than iterating over them all
- the iteration over properties have been moved inside the library, rather than
exposing a list directly
- the unused 'flags' parameter was dropped
---
Makefile.am | 7 +-
src/libsystemd/sd-hwdb/Makefile | 1 +
src/libsystemd/sd-hwdb/hwdb-internal.h | 70 +++++
src/libsystemd/sd-hwdb/hwdb-util.h | 31 +++
src/libsystemd/sd-hwdb/sd-hwdb.c | 471 +++++++++++++++++++++++++++++++++
src/systemd/sd-hwdb.h | 46 ++++
6 files changed, 625 insertions(+), 1 deletion(-)
create mode 120000 src/libsystemd/sd-hwdb/Makefile
create mode 100644 src/libsystemd/sd-hwdb/hwdb-internal.h
create mode 100644 src/libsystemd/sd-hwdb/hwdb-util.h
create mode 100644 src/libsystemd/sd-hwdb/sd-hwdb.c
create mode 100644 src/systemd/sd-hwdb.h
diff --git a/Makefile.am b/Makefile.am
index d4d96e1..f3be5fd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -217,6 +217,7 @@ AM_CPPFLAGS = \
-I $(top_srcdir)/src/libsystemd/sd-event \
-I $(top_srcdir)/src/libsystemd/sd-rtnl \
-I $(top_srcdir)/src/libsystemd/sd-network \
+ -I $(top_srcdir)/src/libsystemd/sd-hwdb \
-I $(top_srcdir)/src/libsystemd-network \
-I $(top_srcdir)/src/libsystemd-terminal \
$(OUR_CPPFLAGS)
@@ -2604,6 +2605,7 @@ libsystemd_internal_la_SOURCES = \
src/systemd/sd-daemon.h \
src/systemd/sd-path.h \
src/systemd/sd-network.h \
+ src/systemd/sd-hwdb.h \
src/libsystemd/sd-bus/sd-bus.c \
src/libsystemd/sd-bus/bus-control.c \
src/libsystemd/sd-bus/bus-control.h \
@@ -2662,7 +2664,10 @@ libsystemd_internal_la_SOURCES = \
src/libsystemd/sd-path/sd-path.c \
src/libsystemd/sd-network/sd-network.c \
src/libsystemd/sd-network/network-util.h \
- src/libsystemd/sd-network/network-util.c
+ src/libsystemd/sd-network/network-util.c \
+ src/libsystemd/sd-hwdb/sd-hwdb.c \
+ src/libsystemd/sd-hwdb/hwdb-util.h \
+ src/libsystemd/sd-hwdb/hwdb-intenal.h
nodist_libsystemd_internal_la_SOURCES = \
src/libsystemd/libsystemd.sym
diff --git a/src/libsystemd/sd-hwdb/Makefile b/src/libsystemd/sd-hwdb/Makefile
new file mode 120000
index 0000000..94aaae2
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/Makefile
@@ -0,0 +1 @@
+../../Makefile
\ No newline at end of file
diff --git a/src/libsystemd/sd-hwdb/hwdb-internal.h b/src/libsystemd/sd-hwdb/hwdb-internal.h
new file mode 100644
index 0000000..fedccde
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/hwdb-internal.h
@@ -0,0 +1,70 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2012 Kay Sievers <kay at vrfy.org>
+
+ 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/>.
+***/
+#pragma once
+
+#include "sparse-endian.h"
+
+#define HWDB_SIG { 'K', 'S', 'L', 'P', 'H', 'H', 'R', 'H' }
+
+/* on-disk trie objects */
+struct trie_header_f {
+ uint8_t signature[8];
+
+ /* version of tool which created the file */
+ le64_t tool_version;
+ le64_t file_size;
+
+ /* size of structures to allow them to grow */
+ le64_t header_size;
+ le64_t node_size;
+ le64_t child_entry_size;
+ le64_t value_entry_size;
+
+ /* offset of the root trie node */
+ le64_t nodes_root_off;
+
+ /* size of the nodes and string section */
+ le64_t nodes_len;
+ le64_t strings_len;
+} _packed_;
+
+struct trie_node_f {
+ /* prefix of lookup string, shared by all children */
+ le64_t prefix_off;
+ /* size of children entry array appended to the node */
+ uint8_t children_count;
+ uint8_t padding[7];
+ /* size of value entry array appended to the node */
+ le64_t values_count;
+} _packed_;
+
+/* array of child entries, follows directly the node record */
+struct trie_child_entry_f {
+ /* index of the child node */
+ uint8_t c;
+ uint8_t padding[7];
+ /* offset of the child node */
+ le64_t child_off;
+} _packed_;
+
+/* array of value entries, follows directly the node record/child array */
+struct trie_value_entry_f {
+ le64_t key_off;
+ le64_t value_off;
+} _packed_;
diff --git a/src/libsystemd/sd-hwdb/hwdb-util.h b/src/libsystemd/sd-hwdb/hwdb-util.h
new file mode 100644
index 0000000..ee020a2
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/hwdb-util.h
@@ -0,0 +1,31 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2014 Tom Gundersen <teg at 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 "util.h"
+
+#include "sd-hwdb.h"
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(sd_hwdb*, sd_hwdb_unref);
+#define _cleanup_hwdb_unref_ _cleanup_(sd_hwdb_unrefp)
+
+bool hwdb_validate(sd_hwdb *hwdb);
diff --git a/src/libsystemd/sd-hwdb/sd-hwdb.c b/src/libsystemd/sd-hwdb/sd-hwdb.c
new file mode 100644
index 0000000..7444ab5
--- /dev/null
+++ b/src/libsystemd/sd-hwdb/sd-hwdb.c
@@ -0,0 +1,471 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2012 Kay Sievers <kay at vrfy.org>
+ Copyright 2008 Alan Jenkins <alan.christopher.jenkins at googlemail.com>
+ Copyright 2014 Tom Gundersen <teg at 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 <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <inttypes.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <fnmatch.h>
+#include <getopt.h>
+#include <sys/mman.h>
+
+#include "sd-hwdb.h"
+
+#include "hashmap.h"
+#include "refcnt.h"
+
+#include "hwdb-util.h"
+#include "hwdb-internal.h"
+
+struct sd_hwdb {
+ RefCount n_ref;
+ int refcount;
+
+ FILE *f;
+ struct stat st;
+ union {
+ struct trie_header_f *head;
+ const char *map;
+ };
+
+ char *modalias;
+
+ 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_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_value_entry_f *trie_node_values(sd_hwdb *hwdb, const struct trie_node_f *node) {
+ const char *base = (const char *)node;
+
+ base += le64toh(hwdb->head->node_size);
+ base += node->children_count * le64toh(hwdb->head->child_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, trie_node_children(hwdb, node), 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 char *key, const char *value) {
+ int r;
+
+ assert(hwdb);
+ assert(key);
+ assert(value);
+
+ /*
+ * Silently ignore all properties which do not start with a
+ * space; future extensions might use additional prefixes.
+ */
+ if (key[0] != ' ')
+ return 0;
+
+ key++;
+
+ r = ordered_hashmap_ensure_allocated(&hwdb->properties, &string_hash_ops);
+ if (r < 0)
+ return r;
+
+ r = ordered_hashmap_replace(hwdb->properties, key, (char*)value);
+ 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_children(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_string(hwdb, trie_node_values(hwdb, node)[i].key_off),
+ trie_string(hwdb, trie_node_values(hwdb, node)[i].value_off));
+ 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 (c == '*' || c == '?' || 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_string(hwdb, trie_node_values(hwdb, node)[n].key_off),
+ trie_string(hwdb, trie_node_values(hwdb, node)[n].value_off));
+ 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"
+#ifdef HAVE_SPLIT_USR
+ "/lib/systemd/hwdb/hwdb.bin\0"
+#endif
+ UDEVLIBEXECDIR "/hwdb.bin\0";
+
+_public_ int sd_hwdb_new(sd_hwdb **ret) {
+ _cleanup_hwdb_unref_ 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 udevadm 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"PRIu64" 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 = hwdb;
+ hwdb = NULL;
+
+ 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);
+ if (hwdb->f)
+ fclose(hwdb->f);
+ free(hwdb->modalias);
+ 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) {
+ _cleanup_free_ char *mod = NULL;
+ int r;
+
+ assert(hwdb);
+ assert(modalias);
+
+ if (streq_ptr(modalias, hwdb->modalias))
+ return 0;
+
+ mod = strdup(modalias);
+ if (!mod)
+ return -ENOMEM;
+
+ ordered_hashmap_clear(hwdb->properties);
+
+ hwdb->properties_modified = true;
+
+ r = trie_search_f(hwdb, modalias);
+ if (r < 0)
+ return r;
+
+ free(hwdb->modalias);
+ hwdb->modalias = mod;
+ mod = NULL;
+
+ return 0;
+}
+
+_public_ int sd_hwdb_get(sd_hwdb *hwdb, const char *modalias, const char *key, const char **_value) {
+ const char *value;
+ 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;
+
+ value = ordered_hashmap_get(hwdb->properties, key);
+ if (!value)
+ return -ENOENT;
+
+ *_value = value;
+
+ 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 void *k, *v;
+
+ assert_return(hwdb, -EINVAL);
+ assert_return(key, -EINVAL);
+ assert_return(value, -EINVAL);
+
+ if (hwdb->properties_modified)
+ return -EAGAIN;
+
+ v = ordered_hashmap_iterate(hwdb->properties, &hwdb->properties_iterator, &k);
+ if (!k)
+ return 0;
+
+ *key = k;
+ *value = v;
+
+ return 1;
+}
diff --git a/src/systemd/sd-hwdb.h b/src/systemd/sd-hwdb.h
new file mode 100644
index 0000000..fae9b9f
--- /dev/null
+++ b/src/systemd/sd-hwdb.h
@@ -0,0 +1,46 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosdhwdbhfoo
+#define foosdhwdbhfoo
+
+/***
+ This file is part of systemd.
+
+ Copyright 2008-2012 Kay Sievers <kay at vrfy.org>
+ Copyright 2014 Tom Gundersen <teg at 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 "_sd-common.h"
+
+_SD_BEGIN_DECLARATIONS;
+
+typedef struct sd_hwdb sd_hwdb;
+
+sd_hwdb *sd_hwdb_ref(sd_hwdb *hwdb);
+sd_hwdb *sd_hwdb_unref(sd_hwdb *hwdb);
+
+int sd_hwdb_new(sd_hwdb **ret);
+
+int sd_hwdb_get(sd_hwdb *hwdb, const char *modalias, const char *key, const char **value);
+
+int sd_hwdb_seek(sd_hwdb *hwdb, const char *modalias);
+int sd_hwdb_enumerate(sd_hwdb *hwdb, const char **key, const char **value);
+
+#define FOREACH_HWDB_PROPERTY(hwdb, modalias, key, value) \
+ if (sd_hwdb_seek(hwdb, modalias) >= 0) \
+ while (sd_hwdb_enumerate(hwdb, &(key), &(value)) > 0)
+
+#endif
--
2.1.0
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