/* * create a COW disk image * * Copyright (c) 2003 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "vl.h" #define NO_THUNK_TYPE_SIZE #include "thunk.h" int cow_create(int cow_fd, const char *image_filename, int64_t image_sectors) { struct cow_header_v2 cow_header; int fd; struct stat st; memset(&cow_header, 0, sizeof(cow_header)); cow_header.magic = htonl(COW_MAGIC); cow_header.version = htonl(COW_VERSION); if (image_filename) { fd = open(image_filename, O_RDONLY); if (fd < 0) { perror(image_filename); exit(1); } image_sectors = lseek64(fd, 0, SEEK_END); if (fstat(fd, &st) != 0) { close(fd); return -1; } close(fd); image_sectors /= 512; cow_header.mtime = htonl(st.st_mtime); realpath(image_filename, cow_header.backing_file); } cow_header.sectorsize = htonl(512); cow_header.size = image_sectors * 512; #ifndef WORDS_BIGENDIAN cow_header.size = bswap64(cow_header.size); #endif write(cow_fd, &cow_header, sizeof(cow_header)); /* resize to include at least all the bitmap */ ftruncate(cow_fd, sizeof(cow_header) + ((image_sectors + 7) >> 3)); lseek(cow_fd, 0, SEEK_SET); return 0; } void help(void) { printf("usage vlmkcow [-h] [-f disk_image] cow_image [cow_size]\n" "Create a Copy On Write disk image from an optional raw disk image\n" "\n" "-f disk_image set the raw disk image name\n" "cow_image the created cow_image\n" "cow_size the create cow_image size in MB if no raw disk image is used\n" "\n" "Once the cow_image is created from a raw disk image, you must not modify the original raw disk image\n" ); exit(1); } int main(int argc, char **argv) { const char *image_filename, *cow_filename; int cow_fd, c, nb_args; int64_t image_size; image_filename = NULL; image_size = 0; for(;;) { c = getopt(argc, argv, "hf:"); if (c == -1) break; switch(c) { case 'h': help(); break; case 'f': image_filename = optarg; break; } } if (!image_filename) nb_args = 2; else nb_args = 1; if (optind + nb_args != argc) help(); cow_filename = argv[optind]; if (nb_args == 2) { image_size = (int64_t)atoi(argv[optind + 1]) * 2 * 1024; } cow_fd = open(cow_filename, O_RDWR | O_CREAT | O_TRUNC, 0644); if (!cow_fd < 0) return -1; if (cow_create(cow_fd, image_filename, image_size) < 0) { fprintf(stderr, "%s: error while formating\n", cow_filename); exit(1); } close(cow_fd); return 0; }