libsystemd: add sd-hwdb library

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

1 files changed, 471 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 0000000000..7444ab5f12
--- /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@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 <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;
+}