FreeCalypso > hg > freecalypso-reveng
view miscprog/pircksum2.c @ 407:183e81c8f6c0
hr-bits: sid-count program written
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Mon, 22 Jul 2024 10:00:58 +0000 |
parents | d69f7512e3c1 |
children |
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/* * This program verifies the correctness of the understanding described in the * ../pirelli/flash2-chksum write-up. */ #include <sys/types.h> #include <sys/file.h> #include <sys/stat.h> #include <sys/mman.h> #include <stdio.h> #include <stdint.h> #include <endian.h> #include <stdlib.h> #include <unistd.h> char *image_filename; u_char *image_map, *endrec; unsigned imgsize, max_imgsize; open_and_map_file() { int fd; struct stat st; fd = open(image_filename, O_RDONLY); if (fd < 0) { perror(image_filename); exit(1); } fstat(fd, &st); if (!S_ISREG(st.st_mode)) { fprintf(stderr, "error: %s is not a regular file\n", image_filename); exit(1); } if (st.st_size != 0x10000 && st.st_size != 0x360000) { fprintf(stderr, "error: %s has an unexpected size\n", image_filename); exit(1); } max_imgsize = st.st_size - 12; image_map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); if (image_map == MAP_FAILED) { perror("mmap"); exit(1); } close(fd); endrec = image_map + max_imgsize; return 0; } verify_chksum1() { uint16_t sum, ref; unsigned offset; sum = 0; for (offset = 0; offset + 1 < imgsize; offset += 2) sum += le16toh(*(uint16_t *)(image_map + offset)); if (imgsize & 1) sum += image_map[offset]; ref = le16toh(*(uint16_t *)(endrec + 8)); if (sum == ref) { printf("Checksum 1 matches (%04X)\n", sum); return 0; } else { printf("Checksum 1 FAILED: computed %04X, stored %04X\n", sum, ref); return 1; } } verify_chksum2() { uint16_t sum, ref; unsigned offset; sum = 0; for (offset = 0; offset < 10; offset += 2) sum += le16toh(*(uint16_t *)(endrec + offset)); ref = le16toh(*(uint16_t *)(endrec + 10)); if (sum == ref) { printf("Checksum 2 matches (%04X)\n", sum); return 0; } else { printf("Checksum 2 FAILED: computed %04X, stored %04X\n", sum, ref); return 1; } } main(argc, argv) char **argv; { int stat1, stat2; if (argc != 2) { fprintf(stderr, "usage: %s image-filename\n", argv[0]); exit(1); } image_filename = argv[1]; open_and_map_file(); if (le32toh(*(uint32_t *)endrec) != 0x12345678) { printf("Error: 0x12345678 signature missing\n"); exit(1); } imgsize = le32toh(*(uint32_t *)(endrec + 4)); if (imgsize < 1 || imgsize > max_imgsize) { printf("Error: bogus image size of 0x%x bytes\n", imgsize); exit(1); } printf("Image size: 0x%x bytes\n", imgsize); stat1 = verify_chksum1(); stat2 = verify_chksum2(); exit(stat1 || stat2); }