1248613Sdes/* 2248613Sdes * Copyright (c) 2012 Damien Miller <djm@mindrot.org> 3248613Sdes * 4248613Sdes * Permission to use, copy, modify, and distribute this software for any 5248613Sdes * purpose with or without fee is hereby granted, provided that the above 6248613Sdes * copyright notice and this permission notice appear in all copies. 7248613Sdes * 8248613Sdes * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9248613Sdes * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10248613Sdes * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11248613Sdes * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12248613Sdes * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13248613Sdes * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14248613Sdes * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15248613Sdes */ 16248613Sdes 17261320Sdes/* $OpenBSD: modpipe.c,v 1.6 2013/11/21 03:16:47 djm Exp $ */ 18248613Sdes 19248613Sdes#include "includes.h" 20248613Sdes 21248613Sdes#include <sys/types.h> 22248613Sdes#include <unistd.h> 23248613Sdes#include <stdio.h> 24248613Sdes#include <string.h> 25248613Sdes#include <stdarg.h> 26248613Sdes#include <stdlib.h> 27248613Sdes#include <errno.h> 28323129Sdes#ifdef HAVE_ERR_H 29323129Sdes# include <err.h> 30323129Sdes#endif 31255670Sdes#include "openbsd-compat/getopt_long.c" 32248613Sdes 33248613Sdesstatic void 34248613Sdesusage(void) 35248613Sdes{ 36248613Sdes fprintf(stderr, "Usage: modpipe -w [-m modspec ...] < in > out\n"); 37248613Sdes fprintf(stderr, "modspec is one of:\n"); 38248613Sdes fprintf(stderr, " xor:offset:value - XOR \"value\" at \"offset\"\n"); 39248613Sdes fprintf(stderr, " andor:offset:val1:val2 - AND \"val1\" then OR \"val2\" at \"offset\"\n"); 40248613Sdes exit(1); 41248613Sdes} 42248613Sdes 43248613Sdes#define MAX_MODIFICATIONS 256 44248613Sdesstruct modification { 45248613Sdes enum { MOD_XOR, MOD_AND_OR } what; 46261320Sdes unsigned long long offset; 47248613Sdes u_int8_t m1, m2; 48248613Sdes}; 49248613Sdes 50248613Sdesstatic void 51248613Sdesparse_modification(const char *s, struct modification *m) 52248613Sdes{ 53248613Sdes char what[16+1]; 54248613Sdes int n, m1, m2; 55248613Sdes 56248613Sdes bzero(m, sizeof(*m)); 57261320Sdes if ((n = sscanf(s, "%16[^:]%*[:]%llu%*[:]%i%*[:]%i", 58248613Sdes what, &m->offset, &m1, &m2)) < 3) 59248613Sdes errx(1, "Invalid modification spec \"%s\"", s); 60248613Sdes if (strcasecmp(what, "xor") == 0) { 61248613Sdes if (n > 3) 62248613Sdes errx(1, "Invalid modification spec \"%s\"", s); 63248613Sdes if (m1 < 0 || m1 > 0xff) 64248613Sdes errx(1, "Invalid XOR modification value"); 65248613Sdes m->what = MOD_XOR; 66248613Sdes m->m1 = m1; 67248613Sdes } else if (strcasecmp(what, "andor") == 0) { 68248613Sdes if (n != 4) 69248613Sdes errx(1, "Invalid modification spec \"%s\"", s); 70248613Sdes if (m1 < 0 || m1 > 0xff) 71248613Sdes errx(1, "Invalid AND modification value"); 72248613Sdes if (m2 < 0 || m2 > 0xff) 73248613Sdes errx(1, "Invalid OR modification value"); 74248613Sdes m->what = MOD_AND_OR; 75248613Sdes m->m1 = m1; 76248613Sdes m->m2 = m2; 77248613Sdes } else 78248613Sdes errx(1, "Invalid modification type \"%s\"", what); 79248613Sdes} 80248613Sdes 81248613Sdesint 82248613Sdesmain(int argc, char **argv) 83248613Sdes{ 84248613Sdes int ch; 85248613Sdes u_char buf[8192]; 86248613Sdes size_t total; 87248613Sdes ssize_t r, s, o; 88248613Sdes struct modification mods[MAX_MODIFICATIONS]; 89248613Sdes u_int i, wflag = 0, num_mods = 0; 90248613Sdes 91248613Sdes while ((ch = getopt(argc, argv, "wm:")) != -1) { 92248613Sdes switch (ch) { 93248613Sdes case 'm': 94248613Sdes if (num_mods >= MAX_MODIFICATIONS) 95248613Sdes errx(1, "Too many modifications"); 96248613Sdes parse_modification(optarg, &(mods[num_mods++])); 97248613Sdes break; 98248613Sdes case 'w': 99248613Sdes wflag = 1; 100248613Sdes break; 101248613Sdes default: 102248613Sdes usage(); 103248613Sdes /* NOTREACHED */ 104248613Sdes } 105248613Sdes } 106248613Sdes for (total = 0;;) { 107248613Sdes r = s = read(STDIN_FILENO, buf, sizeof(buf)); 108248613Sdes if (r == 0) 109248613Sdes break; 110248613Sdes if (r < 0) { 111248613Sdes if (errno == EAGAIN || errno == EINTR) 112248613Sdes continue; 113248613Sdes err(1, "read"); 114248613Sdes } 115248613Sdes for (i = 0; i < num_mods; i++) { 116248613Sdes if (mods[i].offset < total || 117248613Sdes mods[i].offset >= total + s) 118248613Sdes continue; 119248613Sdes switch (mods[i].what) { 120248613Sdes case MOD_XOR: 121248613Sdes buf[mods[i].offset - total] ^= mods[i].m1; 122248613Sdes break; 123248613Sdes case MOD_AND_OR: 124248613Sdes buf[mods[i].offset - total] &= mods[i].m1; 125248613Sdes buf[mods[i].offset - total] |= mods[i].m2; 126248613Sdes break; 127248613Sdes } 128248613Sdes } 129248613Sdes for (o = 0; o < s; o += r) { 130248613Sdes r = write(STDOUT_FILENO, buf, s - o); 131248613Sdes if (r == 0) 132248613Sdes break; 133248613Sdes if (r < 0) { 134248613Sdes if (errno == EAGAIN || errno == EINTR) 135248613Sdes continue; 136248613Sdes err(1, "write"); 137248613Sdes } 138248613Sdes } 139248613Sdes total += s; 140248613Sdes } 141248613Sdes /* Warn if modifications not reached in input stream */ 142248613Sdes r = 0; 143248613Sdes for (i = 0; wflag && i < num_mods; i++) { 144248613Sdes if (mods[i].offset < total) 145248613Sdes continue; 146248613Sdes r = 1; 147248613Sdes fprintf(stderr, "modpipe: warning - mod %u not reached\n", i); 148248613Sdes } 149248613Sdes return r; 150248613Sdes} 151