udev: add hardware database support

1 files changed, 548 insertions, 0 deletions

diff --git a/src/udev/udevadm-hwdb.c b/src/udev/udevadm-hwdb.c
new file mode 100644
index 0000000000..52fe1d4ebc
--- /dev/null
+++ b/src/udev/udevadm-hwdb.c
@@ -0,0 +1,548 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Kay Sievers <kay.sievers@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/>.
+***/
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <string.h>
+
+#include "util.h"
+#include "strbuf.h"
+#include "conf-files.h"
+
+#include "udev.h"
+#include "udev-hwdb.h"
+
+/*
+ * Generic udev properties, key/value database based on modalias strings.
+ * Uses a Patricia/radix trie to index all matches for efficient lookup.
+ */
+
+static const char * const conf_file_dirs[] = {
+        SYSCONFDIR "/udev/hwdb.d",
+        UDEVLIBEXECDIR "/hwdb.d",
+        NULL
+};
+
+/* in-memory trie objects */
+struct trie {
+        struct trie_node *root;
+        struct strbuf *strings;
+
+        size_t nodes_count;
+        size_t children_count;
+        size_t values_count;
+};
+
+struct trie_node {
+        /* prefix, common part for all children of this node */
+        size_t prefix_off;
+
+        /* sorted array of pointers to children nodes */
+        struct trie_child_entry *children;
+        uint8_t children_count;
+
+        /* sorted array of key/value pairs */
+        struct trie_value_entry *values;
+        size_t values_count;
+};
+
+/* children array item with char (0-255) index */
+struct trie_child_entry {
+        uint8_t c;
+        struct trie_node *child;
+};
+
+/* value array item with key/value pairs */
+struct trie_value_entry {
+        size_t key_off;
+        size_t value_off;
+};
+
+static int trie_children_cmp(const void *v1, const void *v2) {
+        const struct trie_child_entry *n1 = v1;
+        const struct trie_child_entry *n2 = v2;
+
+        return n1->c - n2->c;
+}
+
+static int node_add_child(struct trie *trie, struct trie_node *node, struct trie_node *node_child, uint8_t c) {
+        struct trie_child_entry *child;
+        int err = 0;
+
+        /* extend array, add new entry, sort for bisection */
+        child = realloc(node->children, (node->children_count + 1) * sizeof(struct trie_child_entry));
+        if (!child) {
+                err = -ENOMEM;
+                goto out;
+        }
+        node->children = child;
+        trie->children_count++;
+        node->children[node->children_count].c = c;
+        node->children[node->children_count].child = node_child;
+        node->children_count++;
+        qsort(node->children, node->children_count, sizeof(struct trie_child_entry), trie_children_cmp);
+        trie->nodes_count++;
+out:
+        return err;
+}
+
+static struct trie_node *node_lookup(const struct trie_node *node, uint8_t c) {
+        struct trie_child_entry *child;
+        struct trie_child_entry search;
+
+        search.c = c;
+        child = bsearch(&search, node->children, node->children_count, sizeof(struct trie_child_entry), trie_children_cmp);
+        if (child)
+                return child->child;
+        return NULL;
+}
+
+static void trie_node_cleanup(struct trie_node *node) {
+        size_t i;
+
+        for (i = 0; i < node->children_count; i++)
+                trie_node_cleanup(node->children[i].child);
+        free(node->children);
+        free(node->values);
+        free(node);
+}
+
+static int trie_values_cmp(const void *v1, const void *v2, void *arg) {
+        const struct trie_value_entry *val1 = v1;
+        const struct trie_value_entry *val2 = v2;
+        struct trie *trie = arg;
+
+        return strcmp(trie->strings->buf + val1->key_off,
+                      trie->strings->buf + val2->key_off);
+}
+
+static int trie_node_add_value(struct trie *trie, struct trie_node *node,
+                          const char *key, const char *value) {
+        size_t k, v;
+        struct trie_value_entry *val;
+        struct trie_value_entry search;
+
+        k = strbuf_add_string(trie->strings, key, strlen(key));
+        v = strbuf_add_string(trie->strings, value, strlen(value));
+
+        /* replace existing earlier key with new value */
+        search.value_off = k;
+        val = xbsearch_r(&search, node->values, node->values_count, sizeof(struct trie_value_entry), trie_values_cmp, trie);
+        if (val) {
+                val->value_off = v;
+                return 0;
+        }
+
+        /* extend array, add new entry, sort for bisection */
+        val = realloc(node->values, (node->values_count + 1) * sizeof(struct trie_value_entry));
+        if (!val)
+                return -ENOMEM;
+        trie->values_count++;
+        node->values = val;
+        node->values[node->values_count].key_off = k;
+        node->values[node->values_count].value_off = v;
+        node->values_count++;
+        qsort_r(node->values, node->values_count, sizeof(struct trie_value_entry), trie_values_cmp, trie);
+        return 0;
+}
+
+static int trie_insert(struct trie *trie, struct trie_node *node, const char *search,
+                       const char *key, const char *value) {
+        size_t i = 0;
+        int err = 0;
+
+        for (;;) {
+                size_t p;
+                uint8_t c;
+                struct trie_node *child;
+
+                for (p = 0; (c = trie->strings->buf[node->prefix_off + p]); p++) {
+                        char *s;
+                        ssize_t off;
+
+                        if (c == search[i + p])
+                                continue;
+
+                        /* split node */
+                        child = calloc(sizeof(struct trie_node), 1);
+                        if (!child) {
+                                err = -ENOMEM;
+                                goto out;
+                        }
+
+                        /* move values from parent to child */
+                        child->prefix_off = node->prefix_off + p+1;
+                        child->children = node->children;
+                        child->children_count = node->children_count;
+                        child->values = node->values;
+                        child->values_count = node->values_count;
+
+                        /* update parent; use strdup() because the source gets realloc()d */
+                        s = strndup(trie->strings->buf + node->prefix_off, p);
+                        if (!s) {
+                                err = -ENOMEM;
+                                goto out;
+                        }
+                        off = strbuf_add_string(trie->strings, s, p);
+                        free(s);
+                        if (off < 0) {
+                                err = off;
+                                goto out;
+                        }
+                        node->prefix_off = off;
+                        node->children = NULL;
+                        node->children_count = 0;
+                        node->values = NULL;
+                        node->values_count = 0;
+                        err = node_add_child(trie, node, child, c);
+                        if (err)
+                                goto out;
+                        break;
+                }
+                i += p;
+
+                c = search[i];
+                if (c == '\0')
+                        return trie_node_add_value(trie, node, key, value);
+
+                child = node_lookup(node, c);
+                if (!child) {
+                        ssize_t off;
+
+                        /* new child */
+                        child = calloc(sizeof(struct trie_node), 1);
+                        if (!child) {
+                                err = -ENOMEM;
+                                goto out;
+                        }
+                        off = strbuf_add_string(trie->strings, search + i+1, strlen(search + i+1));
+                        if (off < 0) {
+                                err = off;
+                                goto out;
+                        }
+                        child->prefix_off = off;
+                        err = node_add_child(trie, node, child, c);
+                        if (err)
+                                goto out;
+                        return trie_node_add_value(trie, child, key, value);
+                }
+
+                node = child;
+                i++;
+        }
+out:
+        return err;
+}
+
+struct trie_f {
+        FILE *f;
+        struct trie *trie;
+        uint64_t strings_off;
+
+        uint64_t nodes_count;
+        uint64_t children_count;
+        uint64_t values_count;
+};
+
+/* calculate the storage space for the nodes, children arrays, value arrays */
+static void trie_store_nodes_size(struct trie_f *trie, struct trie_node *node) {
+        uint64_t i;
+
+        for (i = 0; i < node->children_count; i++)
+                trie_store_nodes_size(trie, node->children[i].child);
+
+        trie->strings_off += sizeof(struct trie_node_f);
+        for (i = 0; i < node->children_count; i++)
+                trie->strings_off += sizeof(struct trie_child_entry_f);
+        for (i = 0; i < node->values_count; i++)
+                trie->strings_off += sizeof(struct trie_value_entry_f);
+}
+
+static int64_t trie_store_nodes(struct trie_f *trie, struct trie_node *node) {
+        uint64_t i;
+        struct trie_node_f n = {
+                .prefix_off = htole64(trie->strings_off + node->prefix_off),
+                .children_count = node->children_count,
+                .values_count = htole64(node->values_count),
+        };
+        struct trie_child_entry_f *children;
+        int64_t node_off;
+
+        if (node->children_count) {
+                children = new0(struct trie_child_entry_f, node->children_count);
+                if (!children)
+                        return -ENOMEM;
+        }
+
+        /* post-order recursion */
+        for (i = 0; i < node->children_count; i++) {
+                int64_t child_off;
+
+                child_off = trie_store_nodes(trie, node->children[i].child);
+                if (child_off < 0)
+                        return child_off;
+                children[i].c = node->children[i].c;
+                children[i].child_off = htole64(child_off);
+        }
+
+        /* write node */
+        node_off = ftello(trie->f);
+        fwrite(&n, sizeof(struct trie_node_f), 1, trie->f);
+        trie->nodes_count++;
+
+        /* append children array */
+        if (node->children_count) {
+                fwrite(children, sizeof(struct trie_child_entry_f), node->children_count, trie->f);
+                trie->children_count += node->children_count;
+                free(children);
+        }
+
+        /* append values array */
+        for (i = 0; i < node->values_count; i++) {
+                struct trie_value_entry_f v = {
+                        .key_off = htole64(trie->strings_off + node->values[i].key_off),
+                        .value_off = htole64(trie->strings_off + node->values[i].value_off),
+                };
+
+                fwrite(&v, sizeof(struct trie_value_entry_f), 1, trie->f);
+                trie->values_count++;
+        }
+
+        return node_off;
+}
+
+static int trie_store(struct trie *trie, const char *filename) {
+        struct trie_f t = {
+                .trie = trie,
+        };
+        char *filename_tmp;
+        int64_t pos;
+        int64_t root_off;
+        int64_t size;
+        struct trie_header_f h = {
+                .signature = HWDB_SIG,
+                .tool_version = htole64(atoi(VERSION)),
+                .header_size = htole64(sizeof(struct trie_header_f)),
+                .node_size = htole64(sizeof(struct trie_node_f)),
+                .child_entry_size = htole64(sizeof(struct trie_child_entry_f)),
+                .value_entry_size = htole64(sizeof(struct trie_value_entry_f)),
+        };
+        int err;
+
+        /* calculate size of header, nodes, children entries, value entries */
+        t.strings_off = sizeof(struct trie_header_f);
+        trie_store_nodes_size(&t, trie->root);
+
+        err = fopen_temporary(filename , &t.f, &filename_tmp);
+        if (err < 0)
+                return err;
+        fchmod(fileno(t.f), 0444);
+
+        /* write nodes */
+        fseeko(t.f, sizeof(struct trie_header_f), SEEK_SET);
+        root_off = trie_store_nodes(&t, trie->root);
+        h.nodes_root_off = htole64(root_off);
+        pos = ftello(t.f);
+        h.nodes_len = htole64(pos - sizeof(struct trie_header_f));
+
+        /* write string buffer */
+        fwrite(trie->strings->buf, trie->strings->len, 1, t.f);
+        h.strings_len = htole64(trie->strings->len);
+
+        /* write header */
+        size = ftello(t.f);
+        h.file_size = htole64(size);
+        fseeko(t.f, 0, SEEK_SET);
+        fwrite(&h, sizeof(struct trie_header_f), 1, t.f);
+        err = ferror(t.f);
+        if (err)
+                err = -errno;
+        fclose(t.f);
+        if (err < 0 || rename(filename_tmp, filename) < 0) {
+                unlink(filename_tmp);
+                goto out;
+        }
+
+        log_debug("=== trie on-disk ===\n");
+        log_debug("size:             %8zi bytes\n", size);
+        log_debug("header:           %8zu bytes\n", sizeof(struct trie_header_f));
+        log_debug("nodes:            %8zu bytes (%8zi)\n", t.nodes_count * sizeof(struct trie_node_f), t.nodes_count);
+        log_debug("child pointers:   %8zu bytes (%8zi)\n", t.children_count * sizeof(struct trie_child_entry_f), t.children_count);
+        log_debug("value pointers:   %8zu bytes (%8zi)\n", t.values_count * sizeof(struct trie_value_entry_f), t.values_count);
+        log_debug("string store:     %8zu bytes\n", trie->strings->len);
+        log_debug("strings start:    %8llu\n", (unsigned long long) t.strings_off);
+out:
+        free(filename_tmp);
+        return err;
+}
+
+static int import_file(struct trie *trie, const char *filename) {
+        FILE *f;
+        char line[LINE_MAX];
+        char match[LINE_MAX];
+
+        f = fopen(filename, "re");
+        if (f == NULL)
+                return -errno;
+
+        match[0] = '\0';
+        while (fgets(line, sizeof(line), f)) {
+                size_t len;
+
+                if (line[0] == '#')
+                        continue;
+
+                /* new line, new record */
+                if (line[0] == '\n') {
+                        match[0] = '\0';
+                        continue;
+                }
+
+                /* remove newline */
+                len = strlen(line);
+                if (len < 2)
+                        continue;
+                line[len-1] = '\0';
+
+                /* start of new record */
+                if (match[0] == '\0') {
+                        strcpy(match, line);
+                        continue;
+                }
+
+                /* value lines */
+                if (line[0] == ' ') {
+                        char *value;
+
+                        value = strchr(line, '=');
+                        if (!value)
+                                continue;
+                        value[0] = '\0';
+                        value++;
+                        trie_insert(trie, trie->root, match, line, value);
+                }
+        }
+        fclose(f);
+        return 0;
+}
+
+static void help(void) {
+        printf("Usage: udevadm hwdb [--create] [--help]\n"
+               "  --update            update the hardware database\n"
+               "  --help\n\n");
+}
+
+static int adm_hwdb(struct udev *udev, int argc, char *argv[]) {
+        static const struct option options[] = {
+                { "update", no_argument, NULL, 'u' },
+                { "help", no_argument, NULL, 'h' },
+                {}
+        };
+        bool update = false;
+        struct trie *trie;
+        char **files, **f;
+        int err;
+        int rc = EXIT_SUCCESS;
+
+        for (;;) {
+                int option;
+
+                option = getopt_long(argc, argv, "ch", options, NULL);
+                if (option == -1)
+                        break;
+
+                switch (option) {
+                case 'u':
+                        update = true;
+                        break;
+                case 'h':
+                        help();
+                        return EXIT_SUCCESS;
+                }
+        }
+
+        if (!update) {
+                help();
+                return EXIT_SUCCESS;
+        }
+
+        trie = calloc(sizeof(struct trie), 1);
+        if (!trie) {
+                rc = EXIT_FAILURE;
+                goto out;
+        }
+
+        /* string store */
+        trie->strings = strbuf_new();
+        if (!trie->strings) {
+                rc = EXIT_FAILURE;
+                goto out;
+        }
+
+        /* index */
+        trie->root = calloc(sizeof(struct trie_node), 1);
+        if (!trie->root) {
+                rc = EXIT_FAILURE;
+                goto out;
+        }
+        trie->nodes_count++;
+
+        err = conf_files_list_strv(&files, ".hwdb", (const char **)conf_file_dirs);
+        if (err < 0) {
+                log_error("failed to enumerate hwdb files: %s\n", strerror(-err));
+                rc = EXIT_FAILURE;
+                goto out;
+        }
+        STRV_FOREACH(f, files) {
+                log_debug("reading file '%s'", *f);
+                import_file(trie, *f);
+        }
+        strv_free(files);
+
+        strbuf_complete(trie->strings);
+
+        log_debug("=== trie in-memory ===\n");
+        log_debug("nodes:            %8zu bytes (%8zu)\n", trie->nodes_count * sizeof(struct trie_node), trie->nodes_count);
+        log_debug("children arrays:  %8zu bytes (%8zu)\n", trie->children_count * sizeof(struct trie_child_entry), trie->children_count);
+        log_debug("values arrays:    %8zu bytes (%8zu)\n", trie->values_count * sizeof(struct trie_value_entry), trie->values_count);
+        log_debug("strings:          %8zu bytes\n", trie->strings->len);
+        log_debug("strings incoming: %8zu bytes (%8zu)\n", trie->strings->in_len, trie->strings->in_count);
+        log_debug("strings dedup'ed: %8zu bytes (%8zu)\n", trie->strings->dedup_len, trie->strings->dedup_count);
+
+        mkdir_parents(SYSCONFDIR "/udev/hwdb.bin", 0755);
+        err = trie_store(trie, SYSCONFDIR "/udev/hwdb.bin");
+        if (err < 0) {
+                log_error("Failure writing hardware database '%s': %s", SYSCONFDIR "/udev/hwdb.bin", strerror(-err));
+                rc = EXIT_FAILURE;
+        }
+
+out:
+        if (trie->root)
+                trie_node_cleanup(trie->root);
+        strbuf_cleanup(trie->strings);
+        free(trie);
+        return rc;
+}
+
+const struct udevadm_cmd udevadm_hwdb = {
+        .name = "hwdb",
+        .cmd = adm_hwdb,
+        .help = "maintain the hardware database index",
+};