static int qcow_create(const char *filename, int64_t total_size, const char *backing_file, int flags) { int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits; QCowHeader header; uint64_t tmp, offset; QCowCreateState s1, *s = &s1; memset(s, 0, sizeof(*s)); fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); if (fd < 0) return -1; memset(&header, 0, sizeof(header)); header.magic = cpu_to_be32(QCOW_MAGIC); header.version = cpu_to_be32(QCOW_VERSION); header.size = cpu_to_be64(total_size * 512); header_size = sizeof(header); backing_filename_len = 0; if (backing_file) { header.backing_file_offset = cpu_to_be64(header_size); backing_filename_len = strlen(backing_file); header.backing_file_size = cpu_to_be32(backing_filename_len); header_size += backing_filename_len; } s->cluster_bits = 12; /* 4 KB clusters */ s->cluster_size = 1 << s->cluster_bits; header.cluster_bits = cpu_to_be32(s->cluster_bits); header_size = (header_size + 7) & ~7; if (flags & BLOCK_FLAG_ENCRYPT) { header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); } else { header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); } l2_bits = s->cluster_bits - 3; shift = s->cluster_bits + l2_bits; l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift); offset = align_offset(header_size, s->cluster_size); s->l1_table_offset = offset; header.l1_table_offset = cpu_to_be64(s->l1_table_offset); header.l1_size = cpu_to_be32(l1_size); offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size); s->refcount_table = qemu_mallocz(s->cluster_size); s->refcount_block = qemu_mallocz(s->cluster_size); s->refcount_table_offset = offset; header.refcount_table_offset = cpu_to_be64(offset); header.refcount_table_clusters = cpu_to_be32(1); offset += s->cluster_size; s->refcount_table[0] = cpu_to_be64(offset); s->refcount_block_offset = offset; offset += s->cluster_size; /* update refcounts */ create_refcount_update(s, 0, header_size); create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t)); create_refcount_update(s, s->refcount_table_offset, s->cluster_size); create_refcount_update(s, s->refcount_block_offset, s->cluster_size); /* write all the data */ write(fd, &header, sizeof(header)); if (backing_file) { write(fd, backing_file, backing_filename_len); } lseek(fd, s->l1_table_offset, SEEK_SET); tmp = 0; for(i = 0;i < l1_size; i++) { write(fd, &tmp, sizeof(tmp)); } lseek(fd, s->refcount_table_offset, SEEK_SET); write(fd, s->refcount_table, s->cluster_size); lseek(fd, s->refcount_block_offset, SEEK_SET); write(fd, s->refcount_block, s->cluster_size); qemu_free(s->refcount_table); qemu_free(s->refcount_block); close(fd); return 0; }