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https://gitlab.com/qemu-project/qemu
synced 2024-10-15 15:32:51 +00:00
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>
This commit is contained in:
parent
16cdf7ce1a
commit
64a31d5c3d
56
block/dmg.c
56
block/dmg.c
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@ -28,8 +28,6 @@
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#include <zlib.h>
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#include <zlib.h>
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typedef struct BDRVDMGState {
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typedef struct BDRVDMGState {
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int fd;
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/* each chunk contains a certain number of sectors,
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/* each chunk contains a certain number of sectors,
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* offsets[i] is the offset in the .dmg file,
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* offsets[i] is the offset in the .dmg file,
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* lengths[i] is the length of the compressed chunk,
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* lengths[i] is the length of the compressed chunk,
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@ -58,23 +56,23 @@ static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
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return 0;
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return 0;
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}
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}
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static off_t read_off(int fd, int64_t offset)
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static off_t read_off(BlockDriverState *bs, int64_t offset)
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{
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{
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uint64_t buffer;
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uint64_t buffer;
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if (pread(fd, &buffer, 8, offset) < 8)
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if (bdrv_pread(bs->file, offset, &buffer, 8) < 8)
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return 0;
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return 0;
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return be64_to_cpu(buffer);
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return be64_to_cpu(buffer);
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}
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}
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static off_t read_uint32(int fd, int64_t offset)
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static off_t read_uint32(BlockDriverState *bs, int64_t offset)
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{
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{
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uint32_t buffer;
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uint32_t buffer;
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if (pread(fd, &buffer, 4, offset) < 4)
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if (bdrv_pread(bs->file, offset, &buffer, 4) < 4)
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return 0;
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return 0;
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return be32_to_cpu(buffer);
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return be32_to_cpu(buffer);
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}
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}
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static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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static int dmg_open(BlockDriverState *bs, int flags)
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{
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{
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BDRVDMGState *s = bs->opaque;
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BDRVDMGState *s = bs->opaque;
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off_t info_begin,info_end,last_in_offset,last_out_offset;
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off_t info_begin,info_end,last_in_offset,last_out_offset;
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@ -82,29 +80,27 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
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uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
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int64_t offset;
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int64_t offset;
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s->fd = open(filename, O_RDONLY | O_BINARY);
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if (s->fd < 0)
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return -errno;
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bs->read_only = 1;
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bs->read_only = 1;
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s->n_chunks = 0;
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s->n_chunks = 0;
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s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
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s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
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/* read offset of info blocks */
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/* read offset of info blocks */
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offset = lseek(s->fd, -0x1d8, SEEK_END);
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offset = bdrv_getlength(bs->file);
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if (offset < 0) {
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if (offset < 0) {
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goto fail;
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goto fail;
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}
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}
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offset -= 0x1d8;
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info_begin = read_off(s->fd, offset);
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info_begin = read_off(bs, offset);
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if (info_begin == 0) {
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if (info_begin == 0) {
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goto fail;
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goto fail;
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}
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}
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if (read_uint32(s->fd, info_begin) != 0x100) {
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if (read_uint32(bs, info_begin) != 0x100) {
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goto fail;
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goto fail;
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}
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}
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count = read_uint32(s->fd, info_begin + 4);
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count = read_uint32(bs, info_begin + 4);
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if (count == 0) {
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if (count == 0) {
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goto fail;
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goto fail;
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}
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}
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@ -117,12 +113,12 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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while (offset < info_end) {
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while (offset < info_end) {
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uint32_t type;
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uint32_t type;
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count = read_uint32(s->fd, offset);
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count = read_uint32(bs, offset);
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if(count==0)
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if(count==0)
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goto fail;
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goto fail;
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offset += 4;
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offset += 4;
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type = read_uint32(s->fd, offset);
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type = read_uint32(bs, offset);
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if (type == 0x6d697368 && count >= 244) {
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if (type == 0x6d697368 && count >= 244) {
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int new_size, chunk_count;
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int new_size, chunk_count;
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@ -138,7 +134,7 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
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s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
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for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
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for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
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s->types[i] = read_uint32(s->fd, offset);
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s->types[i] = read_uint32(bs, offset);
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offset += 4;
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offset += 4;
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if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
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if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
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if(s->types[i]==0xffffffff) {
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if(s->types[i]==0xffffffff) {
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@ -152,16 +148,16 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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}
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}
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offset += 4;
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offset += 4;
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s->sectors[i] = last_out_offset+read_off(s->fd, offset);
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s->sectors[i] = last_out_offset+read_off(bs, offset);
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offset += 8;
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offset += 8;
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s->sectorcounts[i] = read_off(s->fd, offset);
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s->sectorcounts[i] = read_off(bs, offset);
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offset += 8;
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offset += 8;
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s->offsets[i] = last_in_offset+read_off(s->fd, offset);
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s->offsets[i] = last_in_offset+read_off(bs, offset);
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offset += 8;
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offset += 8;
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s->lengths[i] = read_off(s->fd, offset);
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s->lengths[i] = read_off(bs, offset);
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offset += 8;
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offset += 8;
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if(s->lengths[i]>max_compressed_size)
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if(s->lengths[i]>max_compressed_size)
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@ -183,7 +179,6 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
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return 0;
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return 0;
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fail:
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fail:
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close(s->fd);
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return -1;
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return -1;
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}
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}
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@ -213,8 +208,10 @@ static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
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return s->n_chunks; /* error */
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return s->n_chunks; /* error */
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}
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}
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static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
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static inline int dmg_read_chunk(BlockDriverState *bs, int sector_num)
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{
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{
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BDRVDMGState *s = bs->opaque;
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if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
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if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
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int ret;
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int ret;
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uint32_t chunk = search_chunk(s,sector_num);
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uint32_t chunk = search_chunk(s,sector_num);
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@ -231,8 +228,8 @@ static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
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* inflated. */
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* inflated. */
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i=0;
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i=0;
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do {
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do {
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ret = pread(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i,
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ret = bdrv_pread(bs->file, s->offsets[chunk] + i,
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s->offsets[chunk] + i);
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s->compressed_chunk+i, s->lengths[chunk]-i);
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if(ret<0 && errno==EINTR)
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if(ret<0 && errno==EINTR)
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ret=0;
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ret=0;
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i+=ret;
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i+=ret;
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@ -253,8 +250,8 @@ static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
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return -1;
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return -1;
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break; }
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break; }
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case 1: /* copy */
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case 1: /* copy */
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ret = pread(s->fd, s->uncompressed_chunk, s->lengths[chunk],
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ret = bdrv_pread(bs->file, s->offsets[chunk],
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s->offsets[chunk]);
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s->uncompressed_chunk, s->lengths[chunk]);
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if (ret != s->lengths[chunk])
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if (ret != s->lengths[chunk])
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return -1;
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return -1;
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break;
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break;
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@ -275,7 +272,7 @@ static int dmg_read(BlockDriverState *bs, int64_t sector_num,
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for(i=0;i<nb_sectors;i++) {
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for(i=0;i<nb_sectors;i++) {
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uint32_t sector_offset_in_chunk;
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uint32_t sector_offset_in_chunk;
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if(dmg_read_chunk(s, sector_num+i) != 0)
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if(dmg_read_chunk(bs, sector_num+i) != 0)
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return -1;
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return -1;
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sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
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sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
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memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
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memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
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static void dmg_close(BlockDriverState *bs)
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static void dmg_close(BlockDriverState *bs)
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{
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{
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BDRVDMGState *s = bs->opaque;
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BDRVDMGState *s = bs->opaque;
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close(s->fd);
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if(s->n_chunks>0) {
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if(s->n_chunks>0) {
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free(s->types);
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free(s->types);
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free(s->offsets);
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free(s->offsets);
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.format_name = "dmg",
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.format_name = "dmg",
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.instance_size = sizeof(BDRVDMGState),
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.instance_size = sizeof(BDRVDMGState),
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.bdrv_probe = dmg_probe,
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.bdrv_probe = dmg_probe,
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.bdrv_file_open = dmg_open,
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.bdrv_open = dmg_open,
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.bdrv_read = dmg_read,
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.bdrv_read = dmg_read,
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.bdrv_close = dmg_close,
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.bdrv_close = dmg_close,
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};
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};
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