1 /* $NetBSD: gencheck.c,v 1.6 2024/02/21 22:51:34 christos Exp $ */ 2 3 /* 4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 5 * 6 * SPDX-License-Identifier: MPL-2.0 7 * 8 * This Source Code Form is subject to the terms of the Mozilla Public 9 * License, v. 2.0. If a copy of the MPL was not distributed with this 10 * file, you can obtain one at https://mozilla.org/MPL/2.0/. 11 * 12 * See the COPYRIGHT file distributed with this work for additional 13 * information regarding copyright ownership. 14 */ 15 16 #include <fcntl.h> 17 #include <stdio.h> 18 #include <stdlib.h> 19 #include <string.h> 20 #include <sys/stat.h> 21 #include <unistd.h> 22 23 #include <isc/print.h> 24 25 #define USAGE "usage: gencheck <filename>\n" 26 27 static int 28 check(const char *buf, ssize_t count, size_t *start) { 29 const char chars[] = "abcdefghijklmnopqrstuvwxyz0123456789"; 30 ssize_t i; 31 32 for (i = 0; i < count; i++, *start = (*start + 1) % (sizeof(chars) - 1)) 33 { 34 /* Just ignore the trailing newline */ 35 if (buf[i] == '\n') { 36 continue; 37 } 38 if (buf[i] != chars[*start]) { 39 return (0); 40 } 41 } 42 43 return (1); 44 } 45 46 int 47 main(int argc, char **argv) { 48 int ret; 49 int fd; 50 ssize_t count; 51 char buf[1024]; 52 size_t start; 53 size_t length; 54 55 ret = EXIT_FAILURE; 56 fd = -1; 57 length = 0; 58 59 if (argc != 2) { 60 fprintf(stderr, USAGE); 61 goto out; 62 } 63 64 fd = open(argv[1], O_RDONLY); 65 if (fd == -1) { 66 goto out; 67 } 68 69 start = 0; 70 while ((count = read(fd, buf, sizeof(buf))) != 0) { 71 if (count < 0) { 72 goto out; 73 } 74 75 if (!check(buf, count, &start)) { 76 goto out; 77 } 78 79 length += count; 80 } 81 82 ret = EXIT_SUCCESS; 83 84 out: 85 printf("%lu\n", (unsigned long)length); 86 87 if (fd != -1) { 88 close(fd); 89 } 90 91 return (ret); 92 } 93