diff options
| -rw-r--r-- | block/dmg.c | 88 |
1 files changed, 51 insertions, 37 deletions
diff --git a/block/dmg.c b/block/dmg.c index 02a3d67206..a0ba34fb89 100644 --- a/block/dmg.c +++ b/block/dmg.c @@ -58,18 +58,18 @@ static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) return 0; } -static off_t read_off(int fd) +static off_t read_off(int fd, int64_t offset) { uint64_t buffer; - if(read(fd,&buffer,8)<8) + if (pread(fd, &buffer, 8, offset) < 8) return 0; return be64_to_cpu(buffer); } -static off_t read_uint32(int fd) +static off_t read_uint32(int fd, int64_t offset) { uint32_t buffer; - if(read(fd,&buffer,4)<4) + if (pread(fd, &buffer, 4, offset) < 4) return 0; return be32_to_cpu(buffer); } @@ -80,6 +80,7 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags) off_t info_begin,info_end,last_in_offset,last_out_offset; uint32_t count; 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) @@ -89,38 +90,45 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags) s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; /* read offset of info blocks */ - if(lseek(s->fd,-0x1d8,SEEK_END)<0) { + offset = lseek(s->fd, -0x1d8, SEEK_END); + if (offset < 0) { goto fail; } - info_begin=read_off(s->fd); - if(info_begin==0) - goto fail; - if(lseek(s->fd,info_begin,SEEK_SET)<0) - goto fail; - if(read_uint32(s->fd)!=0x100) - goto fail; - if((count = read_uint32(s->fd))==0) - goto fail; - info_end = info_begin+count; - if(lseek(s->fd,0xf8,SEEK_CUR)<0) + info_begin = read_off(s->fd, offset); + if (info_begin == 0) { goto fail; + } + + if (read_uint32(s->fd, info_begin) != 0x100) { + goto fail; + } + + count = read_uint32(s->fd, info_begin + 4); + if (count == 0) { + goto fail; + } + info_end = info_begin + count; + + offset = info_begin + 0x100; /* read offsets */ last_in_offset = last_out_offset = 0; - while(lseek(s->fd,0,SEEK_CUR)<info_end) { + while (offset < info_end) { uint32_t type; - count = read_uint32(s->fd); + count = read_uint32(s->fd, offset); if(count==0) goto fail; - type = read_uint32(s->fd); - if(type!=0x6d697368 || count<244) - lseek(s->fd,count-4,SEEK_CUR); - else { + offset += 4; + + type = read_uint32(s->fd, offset); + if (type == 0x6d697368 && count >= 244) { int new_size, chunk_count; - if(lseek(s->fd,200,SEEK_CUR)<0) - goto fail; + + offset += 4; + offset += 200; + chunk_count = (count-204)/40; new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); s->types = qemu_realloc(s->types, new_size/2); @@ -130,7 +138,8 @@ 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); + s->types[i] = read_uint32(s->fd, offset); + offset += 4; if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) { if(s->types[i]==0xffffffff) { last_in_offset = s->offsets[i-1]+s->lengths[i-1]; @@ -138,15 +147,23 @@ static int dmg_open(BlockDriverState *bs, const char *filename, int flags) } chunk_count--; i--; - if(lseek(s->fd,36,SEEK_CUR)<0) - goto fail; + offset += 36; continue; } - read_uint32(s->fd); - s->sectors[i] = last_out_offset+read_off(s->fd); - s->sectorcounts[i] = read_off(s->fd); - s->offsets[i] = last_in_offset+read_off(s->fd); - s->lengths[i] = read_off(s->fd); + offset += 4; + + s->sectors[i] = last_out_offset+read_off(s->fd, offset); + offset += 8; + + s->sectorcounts[i] = read_off(s->fd, offset); + offset += 8; + + s->offsets[i] = last_in_offset+read_off(s->fd, offset); + offset += 8; + + s->lengths[i] = read_off(s->fd, offset); + offset += 8; + if(s->lengths[i]>max_compressed_size) max_compressed_size = s->lengths[i]; if(s->sectorcounts[i]>max_sectors_per_chunk) @@ -210,15 +227,12 @@ static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num) case 0x80000005: { /* zlib compressed */ int i; - ret = lseek(s->fd, s->offsets[chunk], SEEK_SET); - if(ret<0) - return -1; - /* we need to buffer, because only the chunk as whole can be * inflated. */ i=0; do { - ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i); + ret = pread(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i, + s->offsets[chunk] + i); if(ret<0 && errno==EINTR) ret=0; i+=ret; |