libvhd.c

xen source 推出最新的VHD操作工具VHD-UTIL 实现源码,超强

/* Copyright (c) 2008, XenSource Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of XenSource Inc. nor the names of its contributors
 *       may be used to endorse or promote products derived from this software
 *       without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <libgen.h>
#include <iconv.h>
#include <sys/mman.h>

#include "libvhd.h"
#include "relative-path.h"

static int libvhd_dbg = 0;

void
libvhd_set_log_level(int level)
{
	if (level)
		libvhd_dbg = 1;
}

#define VHDLOG(_f, _a...)						\
	do {								\
		if (libvhd_dbg)						\
			syslog(LOG_INFO, "libvhd::%s: "_f,		\
			       __func__, ##_a);				\
	} while (0)

#define BIT_MASK 0x80

#ifdef ENABLE_FAILURE_TESTING
const char* ENV_VAR_FAIL[NUM_FAIL_TESTS] = {
	"VHD_UTIL_TEST_FAIL_REPARENT_BEGIN",
	"VHD_UTIL_TEST_FAIL_REPARENT_LOCATOR",
	"VHD_UTIL_TEST_FAIL_REPARENT_END",
	"VHD_UTIL_TEST_FAIL_RESIZE_BEGIN",
	"VHD_UTIL_TEST_FAIL_RESIZE_DATA_MOVED",
	"VHD_UTIL_TEST_FAIL_RESIZE_METADATA_MOVED",
	"VHD_UTIL_TEST_FAIL_RESIZE_END"
};
int TEST_FAIL[NUM_FAIL_TESTS];
#endif // ENABLE_FAILURE_TESTING

static inline int
test_bit (volatile char *addr, int nr)
{
	return ((addr[nr >> 3] << (nr & 7)) & BIT_MASK) != 0;
}

static inline void
set_bit (volatile char *addr, int nr)
{
	addr[nr >> 3] |= (BIT_MASK >> (nr & 7));
}

static inline void
clear_bit (volatile char *addr, int nr)
{
	addr[nr >> 3] &= ~(BIT_MASK >> (nr & 7));
}

static inline int
old_test_bit(volatile char *addr, int nr)
{
	return (((uint32_t *)addr)[nr >> 5] >> (nr & 31)) & 1;
}

static inline void
old_set_bit(volatile char *addr, int nr)
{
	((uint32_t *)addr)[nr >> 5] |= (1 << (nr & 31));
}

static inline void
old_clear_bit(volatile char *addr, int nr)
{
	((uint32_t *)addr)[nr >> 5] &= ~(1 << (nr & 31));
}

void
vhd_footer_in(vhd_footer_t *footer)
{
	BE32_IN(&footer->features);
	BE32_IN(&footer->ff_version);
	BE64_IN(&footer->data_offset);
	BE32_IN(&footer->timestamp);
	BE32_IN(&footer->crtr_ver);
	BE32_IN(&footer->crtr_os);
	BE64_IN(&footer->orig_size);
	BE64_IN(&footer->curr_size);
	BE32_IN(&footer->geometry);
	BE32_IN(&footer->type);
	BE32_IN(&footer->checksum);
}

void
vhd_footer_out(vhd_footer_t *footer)
{
	BE32_OUT(&footer->features);
	BE32_OUT(&footer->ff_version);
	BE64_OUT(&footer->data_offset);
	BE32_OUT(&footer->timestamp);
	BE32_OUT(&footer->crtr_ver);
	BE32_OUT(&footer->crtr_os);
	BE64_OUT(&footer->orig_size);
	BE64_OUT(&footer->curr_size);
	BE32_OUT(&footer->geometry);
	BE32_OUT(&footer->type);
	BE32_OUT(&footer->checksum);
}

void
vhd_header_in(vhd_header_t *header)
{
	int i, n;

	BE64_IN(&header->data_offset);
	BE64_IN(&header->table_offset);
	BE32_IN(&header->hdr_ver);
	BE32_IN(&header->max_bat_size);
	BE32_IN(&header->block_size);
	BE32_IN(&header->checksum);
	BE32_IN(&header->prt_ts);

	n = sizeof(header->loc) / sizeof(vhd_parent_locator_t);

	for (i = 0; i < n; i++) {
		BE32_IN(&header->loc[i].code);
		BE32_IN(&header->loc[i].data_space);
		BE32_IN(&header->loc[i].data_len);
		BE64_IN(&header->loc[i].data_offset);
	}
}

void
vhd_header_out(vhd_header_t *header)
{
	int i, n;

	BE64_OUT(&header->data_offset);
	BE64_OUT(&header->table_offset);
	BE32_OUT(&header->hdr_ver);
	BE32_OUT(&header->max_bat_size);
	BE32_OUT(&header->block_size);
	BE32_OUT(&header->checksum);
	BE32_OUT(&header->prt_ts);

	n = sizeof(header->loc) / sizeof(vhd_parent_locator_t);

	for (i = 0; i < n; i++) {
		BE32_OUT(&header->loc[i].code);
		BE32_OUT(&header->loc[i].data_space);
		BE32_OUT(&header->loc[i].data_len);
		BE64_OUT(&header->loc[i].data_offset);
	}
}

void
vhd_batmap_header_in(vhd_batmap_t *batmap)
{
	BE64_IN(&batmap->header.batmap_offset);
	BE32_IN(&batmap->header.batmap_size);
	BE32_IN(&batmap->header.batmap_version);
	BE32_IN(&batmap->header.checksum);
}

void
vhd_batmap_header_out(vhd_batmap_t *batmap)
{
	BE64_OUT(&batmap->header.batmap_offset);
	BE32_OUT(&batmap->header.batmap_size);
	BE32_OUT(&batmap->header.batmap_version);
	BE32_OUT(&batmap->header.checksum);
}

void
vhd_bat_in(vhd_bat_t *bat)
{
	int i;

	for (i = 0; i < bat->entries; i++)
		BE32_IN(&bat->bat[i]);
}

void
vhd_bat_out(vhd_bat_t *bat)
{
	int i;

	for (i = 0; i < bat->entries; i++)
		BE32_OUT(&bat->bat[i]);
}

uint32_t
vhd_checksum_footer(vhd_footer_t *footer)
{
	int i;
	unsigned char *blob;
	uint32_t checksum, tmp;

	checksum         = 0;
	tmp              = footer->checksum;
	footer->checksum = 0;

	blob = (unsigned char *)footer;
	for (i = 0; i < sizeof(vhd_footer_t); i++)
		checksum += (uint32_t)blob[i];

	footer->checksum = tmp;
	return ~checksum;
}

int
vhd_validate_footer(vhd_footer_t *footer)
{
	int csize;
	uint32_t checksum;

	csize = sizeof(footer->cookie);
	if (memcmp(footer->cookie, HD_COOKIE, csize) != 0 &&
	    memcmp(footer->cookie, VHD_POISON_COOKIE, csize) != 0) {
		char buf[9];
		memcpy(buf, footer->cookie, 8);
		buf[8]= '\0';
		VHDLOG("invalid footer cookie: %s\n", buf);
		return -EINVAL;
	}

	checksum = vhd_checksum_footer(footer);
	if (checksum != footer->checksum) {
		/*
		 * early td-util did not re-calculate
		 * checksum when marking vhds 'hidden'
		 */
		if (footer->hidden &&
		    !strncmp(footer->crtr_app, "tap", 3) &&
		    (footer->crtr_ver == VHD_VERSION(0, 1) ||
		     footer->crtr_ver == VHD_VERSION(1, 1))) {
			char tmp = footer->hidden;
			footer->hidden = 0;
			checksum = vhd_checksum_footer(footer);
			footer->hidden = tmp;

			if (checksum == footer->checksum)
				return 0;
		}

		VHDLOG("invalid footer checksum: "
		       "footer = 0x%08x, calculated = 0x%08x\n",
		       footer->checksum, checksum);
		return -EINVAL;
	}

	return 0;
}

uint32_t
vhd_checksum_header(vhd_header_t *header)
{
	int i;
	unsigned char *blob;
	uint32_t checksum, tmp;

	checksum         = 0;
	tmp              = header->checksum;
	header->checksum = 0;

	blob = (unsigned char *)header;
	for (i = 0; i < sizeof(vhd_header_t); i++)
		checksum += (uint32_t)blob[i];

	header->checksum = tmp;
	return ~checksum;
}

int
vhd_validate_header(vhd_header_t *header)
{
	int i, n;
	uint32_t checksum;

	if (memcmp(header->cookie, DD_COOKIE, 8) != 0) {
		char buf[9];
		memcpy(buf, header->cookie, 8);
		buf[8] = '\0';
		VHDLOG("invalid header cookie: %s\n", buf);
		return -EINVAL;
	}

	if (header->hdr_ver != 0x00010000) {
		VHDLOG("invalid header version 0x%08x\n", header->hdr_ver);
		return -EINVAL;
	}

	if (header->data_offset != 0xFFFFFFFFFFFFFFFF) {
		VHDLOG("invalid header data_offset 0x%016llx\n",
		       header->data_offset);
		return -EINVAL;
	}

	n = sizeof(header->loc) / sizeof(vhd_parent_locator_t);
	for (i = 0; i < n; i++)
		if (vhd_validate_platform_code(header->loc[i].code))
			return -EINVAL;

	checksum = vhd_checksum_header(header);
	if (checksum != header->checksum) {
		VHDLOG("invalid header checksum: "
		       "header = 0x%08x, calculated = 0x%08x\n",
		       header->checksum, checksum);
		return -EINVAL;
	}

	return 0;
}

static inline int
vhd_validate_bat(vhd_bat_t *bat)
{
	if (!bat->bat)
		return -EINVAL;

	return 0;
}

uint32_t
vhd_checksum_batmap(vhd_batmap_t *batmap)
{
	int i, n;
	char *blob;
	uint32_t checksum;

	blob     = batmap->map;
	checksum = 0;

	n = vhd_sectors_to_bytes(batmap->header.batmap_size);

	for (i = 0; i < n; i++) {
		if (batmap->header.batmap_version == VHD_BATMAP_VERSION(1, 1))
			checksum += (uint32_t)blob[i];
		else
			checksum += (uint32_t)(unsigned char)blob[i];
	}

	return ~checksum;
}

int
vhd_validate_batmap_header(vhd_batmap_t *batmap)
{
	if (memcmp(batmap->header.cookie, VHD_BATMAP_COOKIE, 8))
		return -EINVAL;

	if (batmap->header.batmap_version > VHD_BATMAP_CURRENT_VERSION)
		return -EINVAL;

	return 0;
}

int
vhd_validate_batmap(vhd_batmap_t *batmap)
{
	uint32_t checksum;

	if (!batmap->map)
		return -EINVAL;

	checksum = vhd_checksum_batmap(batmap);
	if (checksum != batmap->header.checksum)
		return -EINVAL;

	return 0;
}

int
vhd_batmap_header_offset(vhd_context_t *ctx, off64_t *_off)
{
	off64_t off;
	size_t  bat;

	*_off = 0;

	off  = ctx->header.table_offset;
	bat  = ctx->header.max_bat_size * sizeof(uint32_t);
	off += vhd_bytes_padded(bat);

	*_off = off;
	return 0;
}

int
vhd_validate_platform_code(uint32_t code)
{
	switch (code) {
	case PLAT_CODE_NONE:
	case PLAT_CODE_WI2R:
	case PLAT_CODE_WI2K:
	case PLAT_CODE_W2RU:
	case PLAT_CODE_W2KU:
	case PLAT_CODE_MAC:
	case PLAT_CODE_MACX:
		return 0;
	default:
		VHDLOG("invalid parent locator code %u\n", code);
		return -EINVAL;
	}
}

int
vhd_parent_locator_count(vhd_context_t *ctx)
{
	return (sizeof(ctx->header.loc) / sizeof(vhd_parent_locator_t));
}

int
vhd_hidden(vhd_context_t *ctx, int *hidden)
{
	int err;

	*hidden = 0;

	if (vhd_type_dynamic(ctx) && vhd_creator_tapdisk(ctx) &&
	    (ctx->footer.crtr_ver == VHD_VERSION(0, 1) ||
	     ctx->footer.crtr_ver == VHD_VERSION(1, 1))) {
		vhd_footer_t copy;

		err = vhd_read_footer_at(ctx, &copy, 0);
		if (err) {
			VHDLOG("error reading backup footer of %s: %d\n",
			       ctx->file, err);
			return err;
		}
		*hidden = copy.hidden;
	} else
		*hidden = ctx->footer.hidden;

	return 0;
}

int
vhd_chain_depth(vhd_context_t *ctx, int *depth)
{
	char *file;
	int err, cnt;
	vhd_context_t vhd, *cur;

	err    = 0;
	cnt    = 0;
	*depth = 0;
	file   = NULL;
	cur    = ctx;

	for (;;) {
		cnt++;

		if (cur->footer.type != HD_TYPE_DIFF)
			break;

		if (vhd_parent_raw(cur)) {
			cnt++;
			break;
		}

		err = vhd_parent_locator_get(cur, &file);
		if (err) {
			file = NULL;
			break;
		}

		if (cur != ctx) {
			vhd_close(cur);
			cur = NULL;
		}

		err = vhd_open(&vhd, file, VHD_OPEN_RDONLY);
		if (err)
			break;

		cur = &vhd;
		free(file);
		file = NULL;
	}

	free(file);
	if (cur && cur != ctx)
		vhd_close(cur);

	if (!err)
		*depth = cnt;

	return err;
}

int
vhd_batmap_test(vhd_context_t *ctx, vhd_batmap_t *batmap, uint32_t block)
{
	if (!vhd_has_batmap(ctx) || !batmap->map)
		return 0;

	if (block >= (batmap->header.batmap_size << (VHD_SECTOR_SHIFT + 3)))
		return 0;

	return test_bit(batmap->map, block);
}

void
vhd_batmap_set(vhd_context_t *ctx, vhd_batmap_t *batmap, uint32_t block)
{
	if (!vhd_has_batmap(ctx) || !batmap->map)
		return;

	if (block >= (batmap->header.batmap_size << (VHD_SECTOR_SHIFT + 3)))
		return;

	set_bit(batmap->map, block);
}

void
vhd_batmap_clear(vhd_context_t *ctx, vhd_batmap_t *batmap, uint32_t block)
{
	if (!vhd_has_batmap(ctx) || !batmap->map)
		return;

	if (block >= (batmap->header.batmap_size << (VHD_SECTOR_SHIFT + 3)))
		return;

	clear_bit(batmap->map, block);
}

int
vhd_bitmap_test(vhd_context_t *ctx, char *map, uint32_t block)
{
	if (vhd_creator_tapdisk(ctx) &&
	    ctx->footer.crtr_ver == 0x00000001)
		return old_test_bit(map, block);

	return test_bit(map, block);
}

void
vhd_bitmap_set(vhd_context_t *ctx, char *map, uint32_t block)
{
	if (vhd_creator_tapdisk(ctx) &&
	    ctx->footer.crtr_ver == 0x00000001)
		return old_set_bit(map, block);

	return set_bit(map, block);
}

void
vhd_bitmap_clear(vhd_context_t *ctx, char *map, uint32_t block)
{
	if (vhd_creator_tapdisk(ctx) &&
	    ctx->footer.crtr_ver == 0x00000001)
		return old_clear_bit(map, block);

	return clear_bit(map, block);
}

/*
 * returns absolute offset of the first 
 * byte of the file which is not vhd metadata
 */
int
vhd_end_of_headers(vhd_context_t *ctx, off64_t *end)
{
	int err, i, n;
	uint32_t bat_bytes;
	off64_t eom, bat_end;
	vhd_parent_locator_t *loc;

	*end = 0;

	if (!vhd_type_dynamic(ctx))
		return 0;

	eom       = ctx->footer.data_offset + sizeof(vhd_header_t);

	bat_bytes = vhd_bytes_padded(ctx->header.max_bat_size * sizeof(uint32_t));
	bat_end   = ctx->header.table_offset + bat_bytes;

	eom       = MAX(eom, bat_end);

	if (vhd_has_batmap(ctx)) {
		off64_t hdr_end, hdr_secs, map_end, map_secs;

		err = vhd_get_batmap(ctx);
		if (err)
			return err;

		hdr_secs = secs_round_up_no_zero(sizeof(vhd_batmap_header_t));
		err      = vhd_batmap_header_offset(ctx, &hdr_end);
		if (err)
			return err;

		hdr_end += vhd_sectors_to_bytes(hdr_secs);
		eom      = MAX(eom, hdr_end);

		map_secs = ctx->batmap.header.batmap_size;
		map_end  = (ctx->batmap.header.batmap_offset +
			    vhd_sectors_to_bytes(map_secs));
		eom      = MAX(eom, map_end);
	}

	/* parent locators */
	n = sizeof(ctx->header.loc) / sizeof(vhd_parent_locator_t);

	for (i = 0; i < n; i++) {
		off64_t loc_end;

		loc = &ctx->header.loc[i];
		if (loc->code == PLAT_CODE_NONE)
			continue;

		loc_end = loc->data_offset + vhd_parent_locator_size(loc);
		eom     = MAX(eom, loc_end);
	}

	*end = eom;
	return 0;
}

int
vhd_end_of_data(vhd_context_t *ctx, off64_t *end)
{
	int i, err;
	off64_t max;
	uint64_t blk;

	if (!vhd_type_dynamic(ctx)) {
		err = vhd_seek(ctx, 0, SEEK_END);
		if (err)
			return err;

		max = vhd_position(ctx);
		if (max == (off64_t)-1)