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VMDK: open/read/write for monolithicFlat image 

Parse vmdk decriptor file and open mono flat image.
Read/write the flat extent.

Signed-off-by: Fam Zheng <famcool@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2011-07-19 08:38:22 +08:00 committed by Kevin Wolf
parent 91b85bd388
commit 7fa60fa377
1 changed files with 158 additions and 13 deletions
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171
block/vmdk.c
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@ -65,6 +65,7 @@ typedef struct VmdkExtent {
bool flat;
int64_t sectors;
int64_t end_sector;
int64_t flat_start_offset;
int64_t l1_table_offset;
int64_t l1_backup_table_offset;
uint32_t *l1_table;
@ -407,9 +408,10 @@ fail:
static int vmdk_parent_open(BlockDriverState *bs)
{
char *p_name;
char desc[DESC_SIZE];
char desc[DESC_SIZE + 1];
BDRVVmdkState *s = bs->opaque;
desc[DESC_SIZE] = '\0';
if (bdrv_pread(bs->file, s->desc_offset, desc, DESC_SIZE) != DESC_SIZE) {
return -1;
}
@ -584,6 +586,144 @@ static int vmdk_open_vmdk4(BlockDriverState *bs, int flags)
return ret;
}
/* find an option value out of descriptor file */
static int vmdk_parse_description(const char *desc, const char *opt_name,
char *buf, int buf_size)
{
char *opt_pos, *opt_end;
const char *end = desc + strlen(desc);
opt_pos = strstr(desc, opt_name);
if (!opt_pos) {
return -1;
}
/* Skip "=\"" following opt_name */
opt_pos += strlen(opt_name) + 2;
if (opt_pos >= end) {
return -1;
}
opt_end = opt_pos;
while (opt_end < end && *opt_end != '"') {
opt_end++;
}
if (opt_end == end || buf_size < opt_end - opt_pos + 1) {
return -1;
}
pstrcpy(buf, opt_end - opt_pos + 1, opt_pos);
return 0;
}
static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
const char *desc_file_path)
{
int ret;
char access[11];
char type[11];
char fname[512];
const char *p = desc;
int64_t sectors = 0;
int64_t flat_offset;
while (*p) {
/* parse extent line:
* RW [size in sectors] FLAT "file-name.vmdk" OFFSET
* or
* RW [size in sectors] SPARSE "file-name.vmdk"
*/
flat_offset = -1;
ret = sscanf(p, "%10s %" SCNd64 " %10s %511s %" SCNd64,
access, &sectors, type, fname, &flat_offset);
if (ret < 4 || strcmp(access, "RW")) {
goto next_line;
} else if (!strcmp(type, "FLAT")) {
if (ret != 5 || flat_offset < 0) {
return -EINVAL;
}
} else if (ret != 4) {
return -EINVAL;
}
/* trim the quotation marks around */
if (fname[0] == '"') {
memmove(fname, fname + 1, strlen(fname));
if (strlen(fname) <= 1 || fname[strlen(fname) - 1] != '"') {
return -EINVAL;
}
fname[strlen(fname) - 1] = '\0';
}
if (sectors <= 0 ||
(strcmp(type, "FLAT") && strcmp(type, "SPARSE")) ||
(strcmp(access, "RW"))) {
goto next_line;
}
/* save to extents array */
if (!strcmp(type, "FLAT")) {
/* FLAT extent */
char extent_path[PATH_MAX];
BlockDriverState *extent_file;
VmdkExtent *extent;
path_combine(extent_path, sizeof(extent_path),
desc_file_path, fname);
ret = bdrv_file_open(&extent_file, extent_path, bs->open_flags);
if (ret) {
return ret;
}
extent = vmdk_add_extent(bs, extent_file, true, sectors,
0, 0, 0, 0, sectors);
extent->flat_start_offset = flat_offset;
} else {
/* SPARSE extent, not supported for now */
fprintf(stderr,
"VMDK: Not supported extent type \"%s\""".\n", type);
return -ENOTSUP;
}
next_line:
/* move to next line */
while (*p && *p != '\n') {
p++;
}
p++;
}
return 0;
}
static int vmdk_open_desc_file(BlockDriverState *bs, int flags)
{
int ret;
char buf[2048];
char ct[128];
BDRVVmdkState *s = bs->opaque;
ret = bdrv_pread(bs->file, 0, buf, sizeof(buf));
if (ret < 0) {
return ret;
}
buf[2047] = '\0';
if (vmdk_parse_description(buf, "createType", ct, sizeof(ct))) {
return -EINVAL;
}
if (strcmp(ct, "monolithicFlat")) {
fprintf(stderr,
"VMDK: Not supported image type \"%s\""".\n", ct);
return -ENOTSUP;
}
s->desc_offset = 0;
ret = vmdk_parse_extents(buf, bs, bs->file->filename);
if (ret) {
return ret;
}
/* try to open parent images, if exist */
if (vmdk_parent_open(bs)) {
qemu_free(s->extents);
return -EINVAL;
}
s->parent_cid = vmdk_read_cid(bs, 1);
return 0;
}
static int vmdk_open(BlockDriverState *bs, int flags)
{
uint32_t magic;
@ -598,7 +738,7 @@ static int vmdk_open(BlockDriverState *bs, int flags)
} else if (magic == VMDK4_MAGIC) {
return vmdk_open_vmdk4(bs, flags);
} else {
return -EINVAL;
return vmdk_open_desc_file(bs, flags);
}
}
@ -679,7 +819,7 @@ static int get_cluster_offset(BlockDriverState *bs,
if (m_data)
m_data->valid = 0;
if (extent->flat) {
*cluster_offset = 0;
*cluster_offset = extent->flat_start_offset;
return 0;
}
@ -832,16 +972,20 @@ static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
/* if not allocated, try to read from parent image, if exist */
if (bs->backing_hd) {
if (!vmdk_is_cid_valid(bs))
return -1;
return -EINVAL;
ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
if (ret < 0)
return -1;
return ret;
} else {
memset(buf, 0, 512 * n);
}
} else {
if(bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512) != n * 512)
return -1;
ret = bdrv_pread(extent->file,
cluster_offset + index_in_cluster * 512,
buf, n * 512);
if (ret < 0) {
return ret;
}
}
nb_sectors -= n;
sector_num += n;
@ -865,7 +1009,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
"(VMDK) Wrong offset: sector_num=0x%" PRIx64
" total_sectors=0x%" PRIx64 "\n",
sector_num, bs->total_sectors);
return -1;
return -EIO;
}
while (nb_sectors > 0) {
@ -888,16 +1032,17 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
n = nb_sectors;
}
if (bdrv_pwrite(bs->file,
ret = bdrv_pwrite(extent->file,
cluster_offset + index_in_cluster * 512,
buf, n * 512)
!= n * 512) {
return -1;
buf,
n * 512);
if (ret < 0) {
return ret;
}
if (m_data.valid) {
/* update L2 tables */
if (vmdk_L2update(extent, &m_data) == -1) {
return -1;
return -EIO;
}
}
nb_sectors -= n;