From 64a31d5c3d73396a88563d7a504654edc85aa854 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 12 May 2010 16:31:49 +0200 Subject: 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 Signed-off-by: Kevin Wolf --- block/dmg.c | 56 ++++++++++++++++++++++++++------------------------------ 1 file changed, 26 insertions(+), 30 deletions(-) (limited to 'block/dmg.c') 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 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;in_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;isectors[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, }; -- cgit v1.1