libvhd.c

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

	return vhd_write_header_at(ctx, header, off);
}

int
vhd_write_bat(vhd_context_t *ctx, vhd_bat_t *bat)
{
	int err;
	off64_t off;
	vhd_bat_t b;
	size_t size;

	if (!vhd_type_dynamic(ctx))
		return -EINVAL;

	err = vhd_validate_bat(&ctx->bat);
	if (err)
		return err;

	err = vhd_validate_bat(bat);
	if (err)
		return err;

	memset(&b, 0, sizeof(vhd_bat_t));

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

	err  = vhd_seek(ctx, off, SEEK_SET);
	if (err)
		return err;

	err  = posix_memalign((void **)&b.bat, VHD_SECTOR_SIZE, size);
	if (err)
		return -err;

	memcpy(b.bat, bat->bat, size);
	b.spb     = bat->spb;
	b.entries = bat->entries;
	vhd_bat_out(&b);

	err = vhd_write(ctx, b.bat, size);
	free(b.bat);

	return err;
}

int
vhd_write_batmap(vhd_context_t *ctx, vhd_batmap_t *batmap)
{
	int err;
	off64_t off;
	vhd_batmap_t b;
	char *buf, *map;
	size_t size, map_size;

	buf      = NULL;
	map      = NULL;

	if (!vhd_has_batmap(ctx)) {
		err = -EINVAL;
		goto out;
	}

	b.header = batmap->header;
	b.map    = batmap->map;

	b.header.checksum = vhd_checksum_batmap(&b);
	err = vhd_validate_batmap(&b);
	if (err)
		goto out;

	off      = b.header.batmap_offset;
	map_size = vhd_sectors_to_bytes(b.header.batmap_size);

	err  = vhd_seek(ctx, off, SEEK_SET);
	if (err)
		goto out;

	err  = posix_memalign((void **)&map, VHD_SECTOR_SIZE, map_size);
	if (err) {
		map = NULL;
		err = -err;
		goto out;
	}

	memcpy(map, b.map, map_size);

	err  = vhd_write(ctx, map, map_size);
	if (err)
		goto out;

	err  = vhd_batmap_header_offset(ctx, &off);
	if (err)
		goto out;

	size = vhd_bytes_padded(sizeof(vhd_batmap_header_t));

	err  = vhd_seek(ctx, off, SEEK_SET);
	if (err)
		goto out;

	err  = posix_memalign((void **)&buf, VHD_SECTOR_SIZE, size);
	if (err) {
		err = -err;
		buf = NULL;
		goto out;
	}

	vhd_batmap_header_out(&b);
	memset(buf, 0, size);
	memcpy(buf, &b.header, sizeof(vhd_batmap_header_t));

	err  = vhd_write(ctx, buf, size);

out:
	if (err)
		VHDLOG("%s: failed writing batmap: %d\n", ctx->file, err);
	free(buf);
	free(map);
	return 0;
}

int
vhd_write_bitmap(vhd_context_t *ctx, uint32_t block, char *bitmap)
{
	int err;
	off64_t off;
	uint64_t blk;
	size_t secs, size;

	if (!vhd_type_dynamic(ctx))
		return -EINVAL;

	err = vhd_validate_bat(&ctx->bat);
	if (err)
		return err;

	if (block >= ctx->bat.entries)
		return -ERANGE;

	if ((unsigned long)bitmap & (VHD_SECTOR_SIZE - 1))
		return -EINVAL;

	blk  = ctx->bat.bat[block];
	if (blk == DD_BLK_UNUSED)
		return -EINVAL;

	off  = vhd_sectors_to_bytes(blk);
	size = vhd_sectors_to_bytes(ctx->bm_secs);

	err  = vhd_seek(ctx, off, SEEK_SET);
	if (err)
		return err;

	err  = vhd_write(ctx, bitmap, size);
	if (err)
		return err;

	return 0;
}

int
vhd_write_block(vhd_context_t *ctx, uint32_t block, char *data)
{
	int err;
	off64_t off;
	size_t size;
	uint64_t blk;

	if (!vhd_type_dynamic(ctx))
		return -EINVAL;

	err = vhd_validate_bat(&ctx->bat);
	if (err)
		return err;

	if (block >= ctx->bat.entries)
		return -ERANGE;

	if ((unsigned long)data & ~(VHD_SECTOR_SIZE -1))
		return -EINVAL;

	blk  = ctx->bat.bat[block];
	if (blk == DD_BLK_UNUSED)
		return -EINVAL;

	off  = vhd_sectors_to_bytes(blk + ctx->bm_secs);
	size = vhd_sectors_to_bytes(ctx->spb);

	err  = vhd_seek(ctx, off, SEEK_SET);
	if (err)
		return err;

	err  = vhd_write(ctx, data, size);
	if (err)
		return err;

	return 0;
}

static inline int
namedup(char **dup, const char *name)
{
	*dup = NULL;

	if (strnlen(name, MAX_NAME_LEN) >= MAX_NAME_LEN)
		return -ENAMETOOLONG;
	
	*dup = strdup(name);
	if (*dup == NULL)
		return -ENOMEM;

	return 0;
}

int
vhd_seek(vhd_context_t *ctx, off64_t offset, int whence)
{
	off64_t off;

	off = lseek64(ctx->fd, offset, whence);
	if (off == (off64_t)-1) {
		VHDLOG("%s: seek(0x%08"PRIx64", %d) failed: %d\n",
		       ctx->file, offset, whence, -errno);
		return -errno;
	}

	return 0;
}

off64_t
vhd_position(vhd_context_t *ctx)
{
	return lseek64(ctx->fd, 0, SEEK_CUR);
}

int
vhd_read(vhd_context_t *ctx, void *buf, size_t size)
{
	size_t ret;

	errno = 0;

	ret = read(ctx->fd, buf, size);
	if (ret == size)
		return 0;

	VHDLOG("%s: read of %zu returned %zd, errno: %d\n",
	       ctx->file, size, ret, -errno);

	return (errno ? -errno : -EIO);
}

int
vhd_write(vhd_context_t *ctx, void *buf, size_t size)
{
	size_t ret;

	errno = 0;

	ret = write(ctx->fd, buf, size);
	if (ret == size)
		return 0;

	VHDLOG("%s: write of %zu returned %zd, errno: %d\n",
	       ctx->file, size, ret, -errno);

	return (errno ? -errno : -EIO);
}

int
vhd_offset(vhd_context_t *ctx, uint32_t sector, uint32_t *offset)
{
	int err;
	uint32_t block;

	if (!vhd_type_dynamic(ctx))
		return sector;

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

	block = sector / ctx->spb;
	if (ctx->bat.bat[block] == DD_BLK_UNUSED)
		*offset = DD_BLK_UNUSED;
	else
		*offset = ctx->bat.bat[block] +
			ctx->bm_secs + (sector % ctx->spb);

	return 0;
}

int
vhd_open_fast(vhd_context_t *ctx)
{
	int err;
	char *buf;
	size_t size;

	size = sizeof(vhd_footer_t) + sizeof(vhd_header_t);
	err  = posix_memalign((void **)&buf, VHD_SECTOR_SIZE, size);
	if (err) {
		VHDLOG("failed allocating %s: %d\n", ctx->file, -err);
		return -err;
	}

	err = vhd_read(ctx, buf, size);
	if (err) {
		VHDLOG("failed reading %s: %d\n", ctx->file, err);
		goto out;
	}

	memcpy(&ctx->footer, buf, sizeof(vhd_footer_t));
	vhd_footer_in(&ctx->footer);
	err = vhd_validate_footer(&ctx->footer);
	if (err)
		goto out;

	if (vhd_type_dynamic(ctx)) {
		if (ctx->footer.data_offset != sizeof(vhd_footer_t))
			err = vhd_read_header(ctx, &ctx->header);
		else {
			memcpy(&ctx->header,
			       buf + sizeof(vhd_footer_t),
			       sizeof(vhd_header_t));
			vhd_header_in(&ctx->header);
			err = vhd_validate_header(&ctx->header);
		}

		if (err)
			goto out;

		ctx->spb     = ctx->header.block_size >> VHD_SECTOR_SHIFT;
		ctx->bm_secs = secs_round_up_no_zero(ctx->spb >> 3);
	}

out:
	free(buf);
	return err;
}

int
vhd_open(vhd_context_t *ctx, const char *file, int flags)
{
	int err, oflags;

	if (flags & VHD_OPEN_STRICT)
		vhd_flag_clear(flags, VHD_OPEN_FAST);

	memset(ctx, 0, sizeof(vhd_context_t));
	ctx->fd     = -1;
	ctx->oflags = flags;

	err = namedup(&ctx->file, file);
	if (err)
		return err;

	oflags = O_DIRECT | O_LARGEFILE;
	if (flags & VHD_OPEN_RDONLY)
		oflags |= O_RDONLY;
	if (flags & VHD_OPEN_RDWR)
		oflags |= O_RDWR;

	ctx->fd = open(ctx->file, oflags, 0644);
	if (ctx->fd == -1) {
		err = -errno;
		VHDLOG("failed to open %s: %d\n", ctx->file, err);
		goto fail;
	}

	err = vhd_test_file_fixed(ctx->file, &ctx->is_block);
	if (err)
		goto fail;

	if (flags & VHD_OPEN_FAST) {
		err = vhd_open_fast(ctx);
		if (err)
			goto fail;

		return 0;
	}

	err = vhd_read_footer(ctx, &ctx->footer);
	if (err)
		goto fail;

	if (!(flags & VHD_OPEN_IGNORE_DISABLED) && vhd_disabled(ctx)) {
		err = -EINVAL;
		goto fail;
	}

	if (vhd_type_dynamic(ctx)) {
		err = vhd_read_header(ctx, &ctx->header);
		if (err)
			goto fail;

		ctx->spb     = ctx->header.block_size >> VHD_SECTOR_SHIFT;
		ctx->bm_secs = secs_round_up_no_zero(ctx->spb >> 3);
	}

	return 0;

fail:
	if (ctx->fd != -1)
		close(ctx->fd);
	free(ctx->file);
	memset(ctx, 0, sizeof(vhd_context_t));
	return err;
}

void
vhd_close(vhd_context_t *ctx)
{
	if (ctx->file)
		close(ctx->fd);
	free(ctx->file);
	free(ctx->bat.bat);
	free(ctx->batmap.map);
	memset(ctx, 0, sizeof(vhd_context_t));
}

static inline void
vhd_initialize_footer(vhd_context_t *ctx, int type, uint64_t size)
{
	memset(&ctx->footer, 0, sizeof(vhd_footer_t));
	memcpy(ctx->footer.cookie, HD_COOKIE, sizeof(ctx->footer.cookie));
	ctx->footer.features     = HD_RESERVED;
	ctx->footer.ff_version   = HD_FF_VERSION;
	ctx->footer.timestamp    = vhd_time(time(NULL));
	ctx->footer.crtr_ver     = VHD_CURRENT_VERSION;
	ctx->footer.crtr_os      = 0x00000000;
	ctx->footer.orig_size    = size;
	ctx->footer.curr_size    = size;
	ctx->footer.geometry     = vhd_chs(size);
	ctx->footer.type         = type;
	ctx->footer.saved        = 0;
	ctx->footer.data_offset  = 0xFFFFFFFFFFFFFFFF;
	strcpy(ctx->footer.crtr_app, "tap");
	uuid_generate(ctx->footer.uuid);
}

static int
vhd_initialize_header_parent_name(vhd_context_t *ctx, const char *parent_path)
{
	int err;
	iconv_t cd;
	size_t ibl, obl;
	char *pname, *ppath, *dst;

	err   = 0;
	pname = NULL;
	ppath = NULL;

	/*
	 * MICROSOFT_COMPAT
	 * big endian unicode here 
	 */
	cd = iconv_open(UTF_16BE, "ASCII");
	if (cd == (iconv_t)-1) {
		err = -errno;
		goto out;
	}

	ppath = strdup(parent_path);
	if (!ppath) {
		err = -ENOMEM;
		goto out;
	}

	pname = basename(ppath);
	if (!strcmp(pname, "")) {
		err = -EINVAL;
		goto out;
	}

	ibl = strlen(pname);
	obl = sizeof(ctx->header.prt_name);
	dst = ctx->header.prt_name;

	memset(dst, 0, obl);

	if (iconv(cd, &pname, &ibl, &dst, &obl) == (size_t)-1 || ibl)
		err = (errno ? -errno : -EINVAL);

out:
	iconv_close(cd);
	free(ppath);
	return err;
}

static off64_t
get_file_size(const char *name)
{
	int fd;
	off64_t end;

	fd = open(name, O_LARGEFILE | O_RDONLY);
	if (fd == -1) {
		VHDLOG("unable to open '%s': %d\n", name, errno);
		return -errno;
	}
	end = lseek64(fd, 0, SEEK_END);
	close(fd); 
	return end;
}

static int
vhd_initialize_header(vhd_context_t *ctx, const char *parent_path, 
		uint64_t size, int raw)
{
	int err;
	struct stat stats;
	vhd_context_t parent;

	if (!vhd_type_dynamic(ctx))
		return -EINVAL;

	memset(&ctx->header, 0, sizeof(vhd_header_t));
	memcpy(ctx->header.cookie, DD_COOKIE, sizeof(ctx->header.cookie));
	ctx->header.data_offset  = (uint64_t)-1;
	ctx->header.table_offset = VHD_SECTOR_SIZE * 3; /* 1 ftr + 2 hdr */
	ctx->header.hdr_ver      = DD_VERSION;
	ctx->header.block_size   = VHD_BLOCK_SIZE;
	ctx->header.prt_ts       = 0;
	ctx->header.res1         = 0;
	ctx->header.max_bat_size = (ctx->footer.curr_size +
				    VHD_BLOCK_SIZE - 1) >> VHD_BLOCK_SHIFT;

	ctx->footer.data_offset  = VHD_SECTOR_SIZE;

	if (ctx->footer.type == HD_TYPE_DYNAMIC)
		return 0;

	err = stat(parent_path, &stats);
	if (err == -1)
		return -errno;

	if (raw) {
		ctx->header.prt_ts = vhd_time(stats.st_mtime);
		if (!size)
			size = get_file_size(parent_path);
	}
	else {
		err = vhd_open(&parent, parent_path, VHD_OPEN_RDONLY);
		if (err)
			return err;

		ctx->header.prt_ts = vhd_time(stats.st_mtime);
		uuid_copy(ctx->header.prt_uuid, parent.footer.uuid);
		if (!size)
			size = parent.footer.curr_size;
		vhd_close(&parent);
	}
	ctx->footer.orig_size    = size;
	ctx->footer.curr_size    = size;
	ctx->footer.geometry     = vhd_chs(size);
	ctx->header.max_bat_size = 
		(size + VHD_BLOCK_SIZE - 1) >> VHD_BLOCK_SHIFT;

	return vhd_initialize_header_parent_name(ctx, parent_path);
}

static int
vhd_write_parent_locators(vhd_context_t *ctx, const char *parent)
{
	int i, err;
	off64_t off;
	uint32_t code;

	code = PLAT_CODE_NONE;

	if (ctx->footer.type != HD_TYPE_DIFF)
		return -EINVAL;

	off = ctx->batmap.header.batmap_offset + 
		vhd_sectors_to_bytes(ctx->batmap.header.batmap_size);
	if (off & (VHD_SECTOR_SIZE - 1))
		off = vhd_bytes_padded(off);

	for (i = 0; i < 3; i++) {
		switch (i) {
		case 0:
			code = PLAT_CODE_MACX;
			break;
		case 1:
			code = PLAT_CODE_W2KU;
			break;
		case 2:
			code = PLAT_CODE_W2RU;
			break;
		}

		err = vhd_parent_locator_write_at(ctx, parent, off, code,
						  0, ctx->header.loc + i);
		if (err)
			return err;

		off += vhd_parent_locator_size(ctx->header.loc + i);
	}

	return 0;
}

int
vhd_change_parent(vhd_context_t *child, char *parent_path, int raw)
{
	int i, err;
	char *ppath;
	struct stat stats;
	vhd_context_t parent;

	ppath = realpath(parent_path, NULL);
	if (!ppath) {
		VHDLOG("error resolving parent path %s for %s: %d\n",
		       parent_path, child->file, errno);
		return -errno;
	}

	err = stat(ppath, &stats);
	if (err == -1) {
		err = -errno;
		goto out;
	}

	if (!S_ISREG(stats.st_mode) && !S_ISBLK(stats.st_mode)) {
		err = -EINVAL;
		goto out;
	}

	if (raw) {
		uuid_clear(child->header.prt_uuid);
	} else {
		err = vhd_open(&parent, ppath, VHD_OPEN_RDONLY);
		if (err) {
			VHDLOG("error opening parent %s for %s: %d\n",
			       ppath, child->file, err);
			goto out;
		}
		uuid_copy(child->header.prt_uuid, parent.footer.uuid);
		vhd_close(&parent);
	}

	vhd_initialize_header_parent_name(child, ppath);
	child->header.prt_ts = vhd_time(stats.st_mtime);

	for (i = 0; i < vhd_parent_locator_count(child); i++) {
		vhd_parent_locator_t *loc = child->header.loc + i;
		size_t max = vhd_parent_locator_size(loc);

		switch (loc->code) {
		case PLAT_CODE_MACX:
		case PLAT_CODE_W2KU:
		case PLAT_CODE_W2RU:
			break;
		default:
			continue;
		}

		err = vhd_parent_locator_write_at(child, ppath,
						  loc->data_offset,
						  loc->code, max, loc);
		if (err) {
			VHDLOG("error writing parent locator %d for %s: %d\n",
			       i, child->file, err);
			goto out;