int bdrv_open(BlockDriverState *bs, const char *filename, int snapshot) { int fd; int64_t size; struct cow_header_v2 cow_header; #ifndef _WIN32 char template[] = "/tmp/vl.XXXXXX"; int cow_fd; struct stat st; #endif bs->read_only = 0; bs->fd = -1; bs->cow_fd = -1; bs->cow_bitmap = NULL; strcpy(bs->filename, filename); /* open standard HD image */ #ifdef _WIN32 fd = open(filename, O_RDWR | O_BINARY); #else fd = open(filename, O_RDWR | O_LARGEFILE); #endif if (fd < 0) { /* read only image on disk */ #ifdef _WIN32 fd = open(filename, O_RDONLY | O_BINARY); #else fd = open(filename, O_RDONLY | O_LARGEFILE); #endif if (fd < 0) { perror(filename); goto fail; } if (!snapshot) bs->read_only = 1; } bs->fd = fd; /* see if it is a cow image */ if (read(fd, &cow_header, sizeof(cow_header)) != sizeof(cow_header)) { fprintf(stderr, "%s: could not read header\n", filename); goto fail; } #ifndef _WIN32 if (be32_to_cpu(cow_header.magic) == COW_MAGIC && be32_to_cpu(cow_header.version) == COW_VERSION) { /* cow image found */ size = cow_header.size; #ifndef WORDS_BIGENDIAN size = bswap64(size); #endif bs->total_sectors = size / 512; bs->cow_fd = fd; bs->fd = -1; if (cow_header.backing_file[0] != '\0') { if (stat(cow_header.backing_file, &st) != 0) { fprintf(stderr, "%s: could not find original disk image '%s'\n", filename, cow_header.backing_file); goto fail; } if (st.st_mtime != be32_to_cpu(cow_header.mtime)) { fprintf(stderr, "%s: original raw disk image '%s' does not match saved timestamp\n", filename, cow_header.backing_file); goto fail; } fd = open(cow_header.backing_file, O_RDONLY | O_LARGEFILE); if (fd < 0) goto fail; bs->fd = fd; } /* mmap the bitmap */ bs->cow_bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header); bs->cow_bitmap_addr = mmap(get_mmap_addr(bs->cow_bitmap_size), bs->cow_bitmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, bs->cow_fd, 0); if (bs->cow_bitmap_addr == MAP_FAILED) goto fail; bs->cow_bitmap = bs->cow_bitmap_addr + sizeof(cow_header); bs->cow_sectors_offset = (bs->cow_bitmap_size + 511) & ~511; snapshot = 0; } else #endif { /* standard raw image */ size = lseek64(fd, 0, SEEK_END); bs->total_sectors = size / 512; bs->fd = fd; } #ifndef _WIN32 if (snapshot) { /* create a temporary COW file */ cow_fd = mkstemp64(template); if (cow_fd < 0) goto fail; bs->cow_fd = cow_fd; unlink(template); /* just need to allocate bitmap */ bs->cow_bitmap_size = (bs->total_sectors + 7) >> 3; bs->cow_bitmap_addr = mmap(get_mmap_addr(bs->cow_bitmap_size), bs->cow_bitmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (bs->cow_bitmap_addr == MAP_FAILED) goto fail; bs->cow_bitmap = bs->cow_bitmap_addr; bs->cow_sectors_offset = 0; } #endif bs->inserted = 1; /* call the change callback */ if (bs->change_cb) bs->change_cb(bs->change_opaque); return 0; fail: bdrv_close(bs); return -1; }
int bdrv_open(BlockDriverState *bs, const char *filename, int snapshot) { int fd; int64_t size; struct cow_header_v2 cow_header; #ifndef _WIN32 char template[] = "/tmp/vl.XXXXXX"; int cow_fd; struct stat st; #endif bs->read_only = 0; bs->fd = -1; bs->cow_fd = -1; bs->cow_bitmap = NULL; strcpy(bs->filename, filename);   #ifdef _WIN32 fd = open(filename, O_RDWR | O_BINARY); #else fd = open(filename, O_RDWR | O_LARGEFILE); #endif if (fd < 0) {   #ifdef _WIN32 fd = open(filename, O_RDONLY | O_BINARY); #else fd = open(filename, O_RDONLY | O_LARGEFILE); #endif if (fd < 0) { perror(filename); goto fail; } if (!snapshot) bs->read_only = 1; } bs->fd = fd;   if (read(fd, &cow_header, sizeof(cow_header)) != sizeof(cow_header)) { fprintf(stderr, "%s: could not read header\n", filename); goto fail; } #ifndef _WIN32 if (be32_to_cpu(cow_header.magic) == COW_MAGIC && be32_to_cpu(cow_header.version) == COW_VERSION) {   size = cow_header.size; #ifndef WORDS_BIGENDIAN size = bswap64(size); #endif bs->total_sectors = size / 512; bs->cow_fd = fd; bs->fd = -1; if (cow_header.backing_file[0] != '\0') { if (stat(cow_header.backing_file, &st) != 0) { fprintf(stderr, "%s: could not find original disk image '%s'\n", filename, cow_header.backing_file); goto fail; } if (st.st_mtime != be32_to_cpu(cow_header.mtime)) { fprintf(stderr, "%s: original raw disk image '%s' does not match saved timestamp\n", filename, cow_header.backing_file); goto fail; } fd = open(cow_header.backing_file, O_RDONLY | O_LARGEFILE); if (fd < 0) goto fail; bs->fd = fd; }   bs->cow_bitmap_size = ((bs->total_sectors + 7) >> 3) + sizeof(cow_header); bs->cow_bitmap_addr = mmap(get_mmap_addr(bs->cow_bitmap_size), bs->cow_bitmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, bs->cow_fd, 0); if (bs->cow_bitmap_addr == MAP_FAILED) goto fail; bs->cow_bitmap = bs->cow_bitmap_addr + sizeof(cow_header); bs->cow_sectors_offset = (bs->cow_bitmap_size + 511) & ~511; snapshot = 0; } else #endif {   size = lseek64(fd, 0, SEEK_END); bs->total_sectors = size / 512; bs->fd = fd; } #ifndef _WIN32 if (snapshot) {   cow_fd = mkstemp64(template); if (cow_fd < 0) goto fail; bs->cow_fd = cow_fd; unlink(template);   bs->cow_bitmap_size = (bs->total_sectors + 7) >> 3; bs->cow_bitmap_addr = mmap(get_mmap_addr(bs->cow_bitmap_size), bs->cow_bitmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (bs->cow_bitmap_addr == MAP_FAILED) goto fail; bs->cow_bitmap = bs->cow_bitmap_addr; bs->cow_sectors_offset = 0; } #endif bs->inserted = 1;   if (bs->change_cb) bs->change_cb(bs->change_opaque); return 0; fail: bdrv_close(bs); return -1; }