[people/ms/libloc.git] / src / database.c

/*
	libloc - A library to determine the location of someone on the Internet

	Copyright (C) 2017 IPFire Development Team <info@ipfire.org>

	This library 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.

	This library 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.
*/

#include <arpa/inet.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

#include <loc/libloc.h>
#include <loc/format.h>

#include "libloc-private.h"
#include "as.h"
#include "database.h"
#include "stringpool.h"

struct loc_database {
	struct loc_ctx* ctx;
	int refcount;

	FILE* file;
	unsigned int version;
	off_t vendor;
	off_t description;

	// ASes in the database
	struct loc_as** as;
	size_t as_count;

	struct loc_stringpool* pool;
};

LOC_EXPORT int loc_database_new(struct loc_ctx* ctx, struct loc_database** database, size_t pool_size) {
	struct loc_database* db = calloc(1, sizeof(*db));
	if (!db)
		return -ENOMEM;

	// Reference context
	db->ctx = loc_ref(ctx);
	db->refcount = 1;

	DEBUG(db->ctx, "Database allocated at %p\n", db);

	// Create string pool
	int r = loc_stringpool_new(db->ctx, &db->pool, pool_size);
	if (r) {
		loc_database_unref(db);
		return r;
	}

	*database = db;

	return 0;
}

LOC_EXPORT int loc_database_open(struct loc_ctx* ctx, struct loc_database** database, FILE* f) {
	int r = loc_database_new(ctx, database, 0);
	if (r)
		return r;

	return loc_database_read(*database, f);
}

LOC_EXPORT struct loc_database* loc_database_ref(struct loc_database* db) {
	db->refcount++;

	return db;
}

static void loc_database_free(struct loc_database* db) {
	DEBUG(db->ctx, "Releasing database %p\n", db);

	// Remove references to all ASes
	if (db->as) {
		for (unsigned int i = 0; i < db->as_count; i++) {
			loc_as_unref(db->as[i]);
		}
		free(db->as);
	}

	loc_stringpool_unref(db->pool);

	// Close file
	if (db->file)
		fclose(db->file);

	loc_unref(db->ctx);
	free(db);
}

LOC_EXPORT struct loc_database* loc_database_unref(struct loc_database* db) {
	if (--db->refcount > 0)
		return NULL;

	loc_database_free(db);
	return NULL;
}

LOC_EXPORT const char* loc_database_get_vendor(struct loc_database* db) {
	return loc_stringpool_get(db->pool, db->vendor);
}

LOC_EXPORT int loc_database_set_vendor(struct loc_database* db, const char* vendor) {
	// Add the string to the string pool
	off_t offset = loc_stringpool_add(db->pool, vendor);
	if (offset < 0)
		return offset;

	db->vendor = offset;
	return 0;
}

LOC_EXPORT const char* loc_database_get_description(struct loc_database* db) {
	return loc_stringpool_get(db->pool, db->description);
}

LOC_EXPORT int loc_database_set_description(struct loc_database* db, const char* description) {
	// Add the string to the string pool
	off_t offset = loc_stringpool_add(db->pool, description);
	if (offset < 0)
		return offset;

	db->description = offset;
	return 0;
}

LOC_EXPORT size_t loc_database_count_as(struct loc_database* db) {
	return db->as_count;
}

static int loc_database_has_as(struct loc_database* db, struct loc_as* as) {
	for (unsigned int i = 0; i < db->as_count; i++) {
		if (loc_as_cmp(as, db->as[i]) == 0)
			return i;
	}

	return -1;
}

static int __loc_as_cmp(const void* as1, const void* as2) {
	return loc_as_cmp(*(struct loc_as**)as1, *(struct loc_as**)as2);
}

static void loc_database_sort_ases(struct loc_database* db) {
	qsort(db->as, db->as_count, sizeof(*db->as), __loc_as_cmp);
}

static struct loc_as* __loc_database_add_as(struct loc_database* db, struct loc_as* as) {
	// Check if AS exists already
	int i = loc_database_has_as(db, as);
	if (i >= 0) {
		loc_as_unref(as);

		// Select already existing AS
		as = db->as[i];

		return loc_as_ref(as);
	}

	db->as_count++;

	// Make space for the new entry
	db->as = realloc(db->as, sizeof(*db->as) * db->as_count);

	// Add the new entry at the end
	db->as[db->as_count - 1] = loc_as_ref(as);

	// Sort everything
	loc_database_sort_ases(db);

	return as;
}

LOC_EXPORT struct loc_as* loc_database_add_as(struct loc_database* db, uint32_t number) {
	struct loc_as* as;
	int r = loc_as_new(db->ctx, db->pool, &as, number);
	if (r)
		return NULL;

	return __loc_database_add_as(db, as);
}

static int loc_database_read_magic(struct loc_database* db) {
	struct loc_database_magic magic;

	// Read from file
	size_t bytes_read = fread(&magic, 1, sizeof(magic), db->file);

	// Check if we have been able to read enough data
	if (bytes_read < sizeof(magic)) {
		ERROR(db->ctx, "Could not read enough data to validate magic bytes\n");
		DEBUG(db->ctx, "Read %zu bytes, but needed %zu\n", bytes_read, sizeof(magic));
		return -ENOMSG;
	}

	// Compare magic bytes
	if (memcmp(LOC_DATABASE_MAGIC, magic.magic, strlen(LOC_DATABASE_MAGIC)) == 0) {
		DEBUG(db->ctx, "Magic value matches\n");

		// Parse version
		db->version = ntohs(magic.version);
		DEBUG(db->ctx, "Database version is %u\n", db->version);

		return 0;
	}

	ERROR(db->ctx, "Database format is not compatible\n");

	// Return an error
	return 1;
}

static int loc_database_read_as_section_v0(struct loc_database* db,
		off_t as_offset, size_t as_length) {
	struct loc_database_as_v0 dbobj;

	// Read from the start of the section
	int r = fseek(db->file, as_offset, SEEK_SET);
	if (r)
		return r;

	// Read all ASes
	size_t as_count = as_length / sizeof(dbobj);
	for (unsigned int i = 0; i < as_count; i++) {
		size_t bytes_read = fread(&dbobj, 1, sizeof(dbobj), db->file);
		if (bytes_read < sizeof(dbobj)) {
			ERROR(db->ctx, "Could not read an AS object\n");
			return -ENOMSG;
		}

		// Allocate a new AS
		struct loc_as* as;
		r = loc_as_new_from_database_v0(db->ctx, db->pool, &as, &dbobj);
		if (r)
			return r;

		// Attach it to the database
		as = __loc_database_add_as(db, as);
		loc_as_unref(as);
	}

	INFO(db->ctx, "Read %zu ASes from the database\n", db->as_count);

	return 0;
}

static int loc_database_read_header_v0(struct loc_database* db) {
	struct loc_database_header_v0 header;

	// Read from file
	size_t size = fread(&header, 1, sizeof(header), db->file);

	if (size < sizeof(header)) {
		ERROR(db->ctx, "Could not read enough data for header\n");
		return -ENOMSG;
	}

	// Copy over data
	db->vendor      = ntohl(header.vendor);
	db->description = ntohl(header.description);

	// Open pool
	off_t pool_offset  = ntohl(header.pool_offset);
	size_t pool_length = ntohl(header.pool_length);

	int r = loc_stringpool_read(db->pool, db->file, pool_offset, pool_length);
	if (r)
		return r;

	// AS section
	off_t as_offset  = ntohl(header.as_offset);
	size_t as_length = ntohl(header.as_length);

	r = loc_database_read_as_section_v0(db, as_offset, as_length);
	if (r)
		return r;

	return 0;
}

static int loc_database_read_header(struct loc_database* db) {
	switch (db->version) {
		case 0:
			return loc_database_read_header_v0(db);

		default:
			ERROR(db->ctx, "Incompatible database version: %u\n", db->version);
			return 1;
	}
}

LOC_EXPORT int loc_database_read(struct loc_database* db, FILE* f) {
	// Copy the file pointer and work on that so we don't care if
	// the calling function closes the file
	int fd = fileno(f);

	// Make a copy
	fd = dup(fd);

	// Retrieve a file pointer
	db->file = fdopen(fd, "r");
	if (!db->file)
		return -errno;

	int r = fseek(db->file, 0, SEEK_SET);
	if (r)
		return r;

	// Read magic bytes
	r = loc_database_read_magic(db);
	if (r)
		return r;

	// Read the header
	r = loc_database_read_header(db);
	if (r)
		return r;

	return 0;
}

static void loc_database_make_magic(struct loc_database* db, struct loc_database_magic* magic) {
	// Copy magic bytes
	for (unsigned int i = 0; i < strlen(LOC_DATABASE_MAGIC); i++)
		magic->magic[i] = LOC_DATABASE_MAGIC[i];

	// Set version
	magic->version = htons(LOC_DATABASE_VERSION);
}

LOC_EXPORT int loc_database_write(struct loc_database* db, FILE* f) {
	struct loc_database_magic magic;
	loc_database_make_magic(db, &magic);

	// Make the header
	struct loc_database_header_v0 header;
	header.vendor      = htonl(db->vendor);
	header.description = htonl(db->description);

	int r;
	off_t offset = 0;

	// Start writing at the beginning of the file
	r = fseek(f, 0, SEEK_SET);
	if (r)
		return r;

	// Write the magic
	offset += fwrite(&magic, 1, sizeof(magic), f);

	// Skip the space we need to write the header later
	r = fseek(f, sizeof(header), SEEK_CUR);
	if (r) {
		DEBUG(db->ctx, "Could not seek to position after header\n");
		return r;
	}
	offset += sizeof(header);

	// Write all ASes
	header.as_offset = htonl(offset);

	struct loc_database_as_v0 dbas;
	for (unsigned int i = 0; i < db->as_count; i++) {
		// Convert AS into database format
		loc_as_to_database_v0(db->as[i], &dbas);

		// Write to disk
		offset += fwrite(&dbas, 1, sizeof(dbas), f);
	}
	header.as_length = htonl(db->as_count * sizeof(dbas));

	// Save the offset of the pool section
	DEBUG(db->ctx, "Pool starts at %jd bytes\n", offset);
	header.pool_offset = htonl(offset);

	// Size of the pool
	size_t pool_length = loc_stringpool_write(db->pool, f);
	DEBUG(db->ctx, "Pool has a length of %zu bytes\n", pool_length);
	header.pool_length = htonl(pool_length);

	// Write the header
	r = fseek(f, sizeof(magic), SEEK_SET);
	if (r)
		return r;

	offset += fwrite(&header, 1, sizeof(header), f);

	return 0;
}
Commit	Line	Data
2601e83e MT	1	/*
	2	libloc - A library to determine the location of someone on the Internet
	3
	4	Copyright (C) 2017 IPFire Development Team <info@ipfire.org>
	5
	6	This library is free software; you can redistribute it and/or
	7	modify it under the terms of the GNU Lesser General Public
	8	License as published by the Free Software Foundation; either
	9	version 2.1 of the License, or (at your option) any later version.
	10
	11	This library is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	Lesser General Public License for more details.
	15	*/
	16
	17	#include <arpa/inet.h>
	18	#include <errno.h>
	19	#include <stddef.h>
	20	#include <stdint.h>
	21	#include <stdio.h>
	22	#include <stdlib.h>
	23	#include <string.h>
	24	#include <sys/types.h>
3f35869a	25	#include <unistd.h>
2601e83e MT	26
2601e83e MT	27	#include <loc/libloc.h>
a5db3e49	28	#include <loc/format.h>
2601e83e MT	29
2601e83e MT	30	#include "libloc-private.h"
a5db3e49	31	#include "as.h"
2601e83e MT	32	#include "database.h"
	33	#include "stringpool.h"
	34
	35	struct loc_database {
	36	struct loc_ctx* ctx;
	37	int refcount;
	38
3f35869a	39	FILE* file;
2601e83e MT	40	unsigned int version;
	41	off_t vendor;
	42	off_t description;
	43
a5db3e49 MT	44	// ASes in the database
	45	struct loc_as** as;
	46	size_t as_count;
	47
2601e83e MT	48	struct loc_stringpool* pool;
	49	};
	50
2601e83e MT	51	LOC_EXPORT int loc_database_new(struct loc_ctx* ctx, struct loc_database** database, size_t pool_size) {
	52	struct loc_database* db = calloc(1, sizeof(*db));
	53	if (!db)
	54	return -ENOMEM;
	55
	56	// Reference context
	57	db->ctx = loc_ref(ctx);
	58	db->refcount = 1;
	59
	60	DEBUG(db->ctx, "Database allocated at %p\n", db);
	61
	62	// Create string pool
	63	int r = loc_stringpool_new(db->ctx, &db->pool, pool_size);
	64	if (r) {
	65	loc_database_unref(db);
	66	return r;
	67	}
	68
	69	*database = db;
	70
	71	return 0;
	72	}
	73
	74	LOC_EXPORT int loc_database_open(struct loc_ctx* ctx, struct loc_database** database, FILE* f) {
	75	int r = loc_database_new(ctx, database, 0);
	76	if (r)
	77	return r;
	78
	79	return loc_database_read(*database, f);
	80	}
	81
	82	LOC_EXPORT struct loc_database* loc_database_ref(struct loc_database* db) {
	83	db->refcount++;
	84
	85	return db;
	86	}
	87
	88	static void loc_database_free(struct loc_database* db) {
	89	DEBUG(db->ctx, "Releasing database %p\n", db);
	90
a5db3e49 MT	91	// Remove references to all ASes
	92	if (db->as) {
	93	for (unsigned int i = 0; i < db->as_count; i++) {
	94	loc_as_unref(db->as[i]);
	95	}
	96	free(db->as);
	97	}
	98
2601e83e MT	99	loc_stringpool_unref(db->pool);
2601e83e MT	100
3f35869a MT	101	// Close file
	102	if (db->file)
	103	fclose(db->file);
	104
2601e83e MT	105	loc_unref(db->ctx);
	106	free(db);
	107	}
	108
	109	LOC_EXPORT struct loc_database* loc_database_unref(struct loc_database* db) {
	110	if (--db->refcount > 0)
	111	return NULL;
	112
	113	loc_database_free(db);
	114	return NULL;
	115	}
	116
	117	LOC_EXPORT const char* loc_database_get_vendor(struct loc_database* db) {
	118	return loc_stringpool_get(db->pool, db->vendor);
	119	}
	120
	121	LOC_EXPORT int loc_database_set_vendor(struct loc_database* db, const char* vendor) {
	122	// Add the string to the string pool
	123	off_t offset = loc_stringpool_add(db->pool, vendor);
	124	if (offset < 0)
	125	return offset;
	126
	127	db->vendor = offset;
	128	return 0;
	129	}
	130
	131	LOC_EXPORT const char* loc_database_get_description(struct loc_database* db) {
	132	return loc_stringpool_get(db->pool, db->description);
	133	}
	134
	135	LOC_EXPORT int loc_database_set_description(struct loc_database* db, const char* description) {
	136	// Add the string to the string pool
	137	off_t offset = loc_stringpool_add(db->pool, description);
	138	if (offset < 0)
	139	return offset;
	140
	141	db->description = offset;
	142	return 0;
	143	}
	144
a5db3e49 MT	145	LOC_EXPORT size_t loc_database_count_as(struct loc_database* db) {
	146	return db->as_count;
	147	}
	148
	149	static int loc_database_has_as(struct loc_database* db, struct loc_as* as) {
	150	for (unsigned int i = 0; i < db->as_count; i++) {
	151	if (loc_as_cmp(as, db->as[i]) == 0)
	152	return i;
	153	}
	154
	155	return -1;
	156	}
	157
	158	static int __loc_as_cmp(const void* as1, const void* as2) {
	159	return loc_as_cmp((struct loc_as)as1, (struct loc_as**)as2);
	160	}
	161
	162	static void loc_database_sort_ases(struct loc_database* db) {
	163	qsort(db->as, db->as_count, sizeof(*db->as), __loc_as_cmp);
	164	}
	165
	166	static struct loc_as* __loc_database_add_as(struct loc_database* db, struct loc_as* as) {
	167	// Check if AS exists already
	168	int i = loc_database_has_as(db, as);
	169	if (i >= 0) {
	170	loc_as_unref(as);
	171
	172	// Select already existing AS
	173	as = db->as[i];
	174
	175	return loc_as_ref(as);
	176	}
	177
	178	db->as_count++;
	179
	180	// Make space for the new entry
	181	db->as = realloc(db->as, sizeof(db->as) db->as_count);
	182
	183	// Add the new entry at the end
	184	db->as[db->as_count - 1] = loc_as_ref(as);
	185
	186	// Sort everything
	187	loc_database_sort_ases(db);
	188
	189	return as;
	190	}
	191
	192	LOC_EXPORT struct loc_as* loc_database_add_as(struct loc_database* db, uint32_t number) {
	193	struct loc_as* as;
	194	int r = loc_as_new(db->ctx, db->pool, &as, number);
	195	if (r)
	196	return NULL;
	197
	198	return __loc_database_add_as(db, as);
	199	}
	200
3f35869a	201	static int loc_database_read_magic(struct loc_database* db) {
2601e83e MT	202	struct loc_database_magic magic;
	203
	204	// Read from file
3f35869a	205	size_t bytes_read = fread(&magic, 1, sizeof(magic), db->file);
2601e83e MT	206
	207	// Check if we have been able to read enough data
	208	if (bytes_read < sizeof(magic)) {
	209	ERROR(db->ctx, "Could not read enough data to validate magic bytes\n");
	210	DEBUG(db->ctx, "Read %zu bytes, but needed %zu\n", bytes_read, sizeof(magic));
	211	return -ENOMSG;
	212	}
	213
	214	// Compare magic bytes
	215	if (memcmp(LOC_DATABASE_MAGIC, magic.magic, strlen(LOC_DATABASE_MAGIC)) == 0) {
	216	DEBUG(db->ctx, "Magic value matches\n");
	217
	218	// Parse version
	219	db->version = ntohs(magic.version);
	220	DEBUG(db->ctx, "Database version is %u\n", db->version);
	221
	222	return 0;
	223	}
	224
	225	ERROR(db->ctx, "Database format is not compatible\n");
	226
	227	// Return an error
	228	return 1;
	229	}
	230
a5db3e49	231	static int loc_database_read_as_section_v0(struct loc_database* db,
3f35869a	232	off_t as_offset, size_t as_length) {
a5db3e49 MT	233	struct loc_database_as_v0 dbobj;
	234
	235	// Read from the start of the section
3f35869a	236	int r = fseek(db->file, as_offset, SEEK_SET);
a5db3e49 MT	237	if (r)
	238	return r;
	239
	240	// Read all ASes
	241	size_t as_count = as_length / sizeof(dbobj);
	242	for (unsigned int i = 0; i < as_count; i++) {
3f35869a	243	size_t bytes_read = fread(&dbobj, 1, sizeof(dbobj), db->file);
a5db3e49 MT	244	if (bytes_read < sizeof(dbobj)) {
	245	ERROR(db->ctx, "Could not read an AS object\n");
	246	return -ENOMSG;
	247	}
	248
	249	// Allocate a new AS
	250	struct loc_as* as;
	251	r = loc_as_new_from_database_v0(db->ctx, db->pool, &as, &dbobj);
	252	if (r)
	253	return r;
	254
	255	// Attach it to the database
	256	as = __loc_database_add_as(db, as);
	257	loc_as_unref(as);
	258	}
	259
	260	INFO(db->ctx, "Read %zu ASes from the database\n", db->as_count);
	261
	262	return 0;
	263	}
	264
3f35869a	265	static int loc_database_read_header_v0(struct loc_database* db) {
2601e83e MT	266	struct loc_database_header_v0 header;
	267
	268	// Read from file
3f35869a	269	size_t size = fread(&header, 1, sizeof(header), db->file);
2601e83e MT	270
	271	if (size < sizeof(header)) {
	272	ERROR(db->ctx, "Could not read enough data for header\n");
	273	return -ENOMSG;
	274	}
	275
	276	// Copy over data
	277	db->vendor = ntohl(header.vendor);
	278	db->description = ntohl(header.description);
	279
	280	// Open pool
	281	off_t pool_offset = ntohl(header.pool_offset);
	282	size_t pool_length = ntohl(header.pool_length);
	283
3f35869a	284	int r = loc_stringpool_read(db->pool, db->file, pool_offset, pool_length);
2601e83e MT	285	if (r)
	286	return r;
	287
a5db3e49 MT	288	// AS section
	289	off_t as_offset = ntohl(header.as_offset);
	290	size_t as_length = ntohl(header.as_length);
	291
3f35869a	292	r = loc_database_read_as_section_v0(db, as_offset, as_length);
a5db3e49 MT	293	if (r)
	294	return r;
	295
2601e83e MT	296	return 0;
	297	}
	298
3f35869a	299	static int loc_database_read_header(struct loc_database* db) {
2601e83e MT	300	switch (db->version) {
2601e83e MT	301	case 0:
3f35869a	302	return loc_database_read_header_v0(db);
2601e83e MT	303
	304	default:
	305	ERROR(db->ctx, "Incompatible database version: %u\n", db->version);
	306	return 1;
	307	}
	308	}
	309
	310	LOC_EXPORT int loc_database_read(struct loc_database* db, FILE* f) {
3f35869a MT	311	// Copy the file pointer and work on that so we don't care if
	312	// the calling function closes the file
	313	int fd = fileno(f);
	314
	315	// Make a copy
	316	fd = dup(fd);
	317
	318	// Retrieve a file pointer
	319	db->file = fdopen(fd, "r");
	320	if (!db->file)
	321	return -errno;
	322
	323	int r = fseek(db->file, 0, SEEK_SET);
2601e83e MT	324	if (r)
	325	return r;
	326
	327	// Read magic bytes
3f35869a	328	r = loc_database_read_magic(db);
2601e83e MT	329	if (r)
	330	return r;
	331
	332	// Read the header
3f35869a	333	r = loc_database_read_header(db);
2601e83e MT	334	if (r)
	335	return r;
	336
	337	return 0;
	338	}
	339
	340	static void loc_database_make_magic(struct loc_database* db, struct loc_database_magic* magic) {
	341	// Copy magic bytes
	342	for (unsigned int i = 0; i < strlen(LOC_DATABASE_MAGIC); i++)
	343	magic->magic[i] = LOC_DATABASE_MAGIC[i];
	344
	345	// Set version
	346	magic->version = htons(LOC_DATABASE_VERSION);
	347	}
	348
	349	LOC_EXPORT int loc_database_write(struct loc_database* db, FILE* f) {
	350	struct loc_database_magic magic;
	351	loc_database_make_magic(db, &magic);
	352
	353	// Make the header
	354	struct loc_database_header_v0 header;
	355	header.vendor = htonl(db->vendor);
	356	header.description = htonl(db->description);
	357
	358	int r;
	359	off_t offset = 0;
	360
	361	// Start writing at the beginning of the file
	362	r = fseek(f, 0, SEEK_SET);
	363	if (r)
	364	return r;
	365
	366	// Write the magic
	367	offset += fwrite(&magic, 1, sizeof(magic), f);
	368
	369	// Skip the space we need to write the header later
	370	r = fseek(f, sizeof(header), SEEK_CUR);
	371	if (r) {
	372	DEBUG(db->ctx, "Could not seek to position after header\n");
	373	return r;
	374	}
	375	offset += sizeof(header);
	376
a5db3e49 MT	377	// Write all ASes
	378	header.as_offset = htonl(offset);
	379
	380	struct loc_database_as_v0 dbas;
	381	for (unsigned int i = 0; i < db->as_count; i++) {
	382	// Convert AS into database format
	383	loc_as_to_database_v0(db->as[i], &dbas);
	384
	385	// Write to disk
	386	offset += fwrite(&dbas, 1, sizeof(dbas), f);
	387	}
	388	header.as_length = htonl(db->as_count * sizeof(dbas));
	389
2601e83e MT	390	// Save the offset of the pool section
	391	DEBUG(db->ctx, "Pool starts at %jd bytes\n", offset);
	392	header.pool_offset = htonl(offset);
	393
	394	// Size of the pool
	395	size_t pool_length = loc_stringpool_write(db->pool, f);
	396	DEBUG(db->ctx, "Pool has a length of %zu bytes\n", pool_length);
	397	header.pool_length = htonl(pool_length);
	398
	399	// Write the header
	400	r = fseek(f, sizeof(magic), SEEK_SET);
	401	if (r)
	402	return r;
	403
	404	offset += fwrite(&header, 1, sizeof(header), f);
	405
	406	return 0;
	407	}