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authorChristoph Hellwig <hch@lst.de>2010-05-12 16:31:49 +0200
committerKevin Wolf <kwolf@redhat.com>2010-05-17 10:20:05 +0200
commit64a31d5c3d73396a88563d7a504654edc85aa854 (patch)
tree5c829c6d09e17050d2079d1eaed201d5a5346ca6 /block/dmg.c
parent16cdf7ce1a53dcab75f5206a89bf98bb907a8b9e (diff)
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dmg: use qemu block API
Use bdrv_pwrite to access the backing device instead of pread, and convert the driver to implementing the bdrv_open method which gives it an already opened BlockDriverState for the underlying device. Dmg actually does an lseek to a negative offset in the open routine, which we replace with offset arithmetics after doing a bdrv_getlength. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/dmg.c')
-rw-r--r--block/dmg.c56
1 files changed, 26 insertions, 30 deletions
diff --git a/block/dmg.c b/block/dmg.c
index a0ba34f..a3c815b 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -28,8 +28,6 @@
#include <zlib.h>
typedef struct BDRVDMGState {
- int fd;
-
/* each chunk contains a certain number of sectors,
* offsets[i] is the offset in the .dmg file,
* lengths[i] is the length of the compressed chunk,
@@ -58,23 +56,23 @@ static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
return 0;
}
-static off_t read_off(int fd, int64_t offset)
+static off_t read_off(BlockDriverState *bs, int64_t offset)
{
uint64_t buffer;
- if (pread(fd, &buffer, 8, offset) < 8)
+ if (bdrv_pread(bs->file, offset, &buffer, 8) < 8)
return 0;
return be64_to_cpu(buffer);
}
-static off_t read_uint32(int fd, int64_t offset)
+static off_t read_uint32(BlockDriverState *bs, int64_t offset)
{
uint32_t buffer;
- if (pread(fd, &buffer, 4, offset) < 4)
+ if (bdrv_pread(bs->file, offset, &buffer, 4) < 4)
return 0;
return be32_to_cpu(buffer);
}
-static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
+static int dmg_open(BlockDriverState *bs, int flags)
{
BDRVDMGState *s = bs->opaque;
off_t info_begin,info_end,last_in_offset,last_out_offset;
@@ -82,29 +80,27 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
int64_t offset;
- s->fd = open(filename, O_RDONLY | O_BINARY);
- if (s->fd < 0)
- return -errno;
bs->read_only = 1;
s->n_chunks = 0;
s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
/* read offset of info blocks */
- offset = lseek(s->fd, -0x1d8, SEEK_END);
+ offset = bdrv_getlength(bs->file);
if (offset < 0) {
goto fail;
}
+ offset -= 0x1d8;
- info_begin = read_off(s->fd, offset);
+ info_begin = read_off(bs, offset);
if (info_begin == 0) {
goto fail;
}
- if (read_uint32(s->fd, info_begin) != 0x100) {
+ if (read_uint32(bs, info_begin) != 0x100) {
goto fail;
}
- count = read_uint32(s->fd, info_begin + 4);
+ count = read_uint32(bs, info_begin + 4);
if (count == 0) {
goto fail;
}
@@ -117,12 +113,12 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
while (offset < info_end) {
uint32_t type;
- count = read_uint32(s->fd, offset);
+ count = read_uint32(bs, offset);
if(count==0)
goto fail;
offset += 4;
- type = read_uint32(s->fd, offset);
+ type = read_uint32(bs, offset);
if (type == 0x6d697368 && count >= 244) {
int new_size, chunk_count;
@@ -138,7 +134,7 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
- s->types[i] = read_uint32(s->fd, offset);
+ s->types[i] = read_uint32(bs, offset);
offset += 4;
if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
if(s->types[i]==0xffffffff) {
@@ -152,16 +148,16 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
}
offset += 4;
- s->sectors[i] = last_out_offset+read_off(s->fd, offset);
+ s->sectors[i] = last_out_offset+read_off(bs, offset);
offset += 8;
- s->sectorcounts[i] = read_off(s->fd, offset);
+ s->sectorcounts[i] = read_off(bs, offset);
offset += 8;
- s->offsets[i] = last_in_offset+read_off(s->fd, offset);
+ s->offsets[i] = last_in_offset+read_off(bs, offset);
offset += 8;
- s->lengths[i] = read_off(s->fd, offset);
+ s->lengths[i] = read_off(bs, offset);
offset += 8;
if(s->lengths[i]>max_compressed_size)
@@ -183,7 +179,6 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
return 0;
fail:
- close(s->fd);
return -1;
}
@@ -213,8 +208,10 @@ static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
return s->n_chunks; /* error */
}
-static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
+static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num)
{
+ BDRVDMGState *s = bs->opaque;
+
if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
int ret;
uint32_t chunk = search_chunk(s,sector_num);
@@ -231,8 +228,8 @@ static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
* inflated. */
i=0;
do {
- ret = pread(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i,
- s->offsets[chunk] + i);
+ ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
+ s->compressed_chunk+i, s->lengths[chunk]-i);
if(ret<0 && errno==EINTR)
ret=0;
i+=ret;
@@ -253,8 +250,8 @@ static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
return -1;
break; }
case 1: /* copy */
- ret = pread(s->fd, s->uncompressed_chunk, s->lengths[chunk],
- s->offsets[chunk]);
+ ret = bdrv_pread(bs->file, s->offsets[chunk],
+ s->uncompressed_chunk, s->lengths[chunk]);
if (ret != s->lengths[chunk])
return -1;
break;
@@ -275,7 +272,7 @@ static int dmg_read(BlockDriverState *bs, int64_t sector_num,
for(i=0;i<nb_sectors;i++) {
uint32_t sector_offset_in_chunk;
- if(dmg_read_chunk(s, sector_num+i) != 0)
+ if(dmg_read_chunk(bs, sector_num+i) != 0)
return -1;
sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
@@ -286,7 +283,6 @@ static int dmg_read(BlockDriverState *bs, int64_t sector_num,
static void dmg_close(BlockDriverState *bs)
{
BDRVDMGState *s = bs->opaque;
- close(s->fd);
if(s->n_chunks>0) {
free(s->types);
free(s->offsets);
@@ -303,7 +299,7 @@ static BlockDriver bdrv_dmg = {
.format_name = "dmg",
.instance_size = sizeof(BDRVDMGState),
.bdrv_probe = dmg_probe,
- .bdrv_file_open = dmg_open,
+ .bdrv_open = dmg_open,
.bdrv_read = dmg_read,
.bdrv_close = dmg_close,
};