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 17262566Sdes/* $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> 28255670Sdes#include "openbsd-compat/getopt_long.c" 29248613Sdes 30248613Sdesstatic void err(int, const char *, ...) __attribute__((format(printf, 2, 3))); 31248613Sdesstatic void errx(int, const char *, ...) __attribute__((format(printf, 2, 3))); 32248613Sdes 33248613Sdesstatic void 34248613Sdeserr(int r, const char *fmt, ...) 35248613Sdes{ 36248613Sdes va_list args; 37248613Sdes 38248613Sdes va_start(args, fmt); 39248613Sdes fprintf(stderr, "%s: ", strerror(errno)); 40248613Sdes vfprintf(stderr, fmt, args); 41248613Sdes fputc('\n', stderr); 42248613Sdes va_end(args); 43248613Sdes exit(r); 44248613Sdes} 45248613Sdes 46248613Sdesstatic void 47248613Sdeserrx(int r, const char *fmt, ...) 48248613Sdes{ 49248613Sdes va_list args; 50248613Sdes 51248613Sdes va_start(args, fmt); 52248613Sdes vfprintf(stderr, fmt, args); 53248613Sdes fputc('\n', stderr); 54248613Sdes va_end(args); 55248613Sdes exit(r); 56248613Sdes} 57248613Sdes 58248613Sdesstatic void 59248613Sdesusage(void) 60248613Sdes{ 61248613Sdes fprintf(stderr, "Usage: modpipe -w [-m modspec ...] < in > out\n"); 62248613Sdes fprintf(stderr, "modspec is one of:\n"); 63248613Sdes fprintf(stderr, " xor:offset:value - XOR \"value\" at \"offset\"\n"); 64248613Sdes fprintf(stderr, " andor:offset:val1:val2 - AND \"val1\" then OR \"val2\" at \"offset\"\n"); 65248613Sdes exit(1); 66248613Sdes} 67248613Sdes 68248613Sdes#define MAX_MODIFICATIONS 256 69248613Sdesstruct modification { 70248613Sdes enum { MOD_XOR, MOD_AND_OR } what; 71262566Sdes unsigned long long offset; 72248613Sdes u_int8_t m1, m2; 73248613Sdes}; 74248613Sdes 75248613Sdesstatic void 76248613Sdesparse_modification(const char *s, struct modification *m) 77248613Sdes{ 78248613Sdes char what[16+1]; 79248613Sdes int n, m1, m2; 80248613Sdes 81248613Sdes bzero(m, sizeof(*m)); 82262566Sdes if ((n = sscanf(s, "%16[^:]%*[:]%llu%*[:]%i%*[:]%i", 83248613Sdes what, &m->offset, &m1, &m2)) < 3) 84248613Sdes errx(1, "Invalid modification spec \"%s\"", s); 85248613Sdes if (strcasecmp(what, "xor") == 0) { 86248613Sdes if (n > 3) 87248613Sdes errx(1, "Invalid modification spec \"%s\"", s); 88248613Sdes if (m1 < 0 || m1 > 0xff) 89248613Sdes errx(1, "Invalid XOR modification value"); 90248613Sdes m->what = MOD_XOR; 91248613Sdes m->m1 = m1; 92248613Sdes } else if (strcasecmp(what, "andor") == 0) { 93248613Sdes if (n != 4) 94248613Sdes errx(1, "Invalid modification spec \"%s\"", s); 95248613Sdes if (m1 < 0 || m1 > 0xff) 96248613Sdes errx(1, "Invalid AND modification value"); 97248613Sdes if (m2 < 0 || m2 > 0xff) 98248613Sdes errx(1, "Invalid OR modification value"); 99248613Sdes m->what = MOD_AND_OR; 100248613Sdes m->m1 = m1; 101248613Sdes m->m2 = m2; 102248613Sdes } else 103248613Sdes errx(1, "Invalid modification type \"%s\"", what); 104248613Sdes} 105248613Sdes 106248613Sdesint 107248613Sdesmain(int argc, char **argv) 108248613Sdes{ 109248613Sdes int ch; 110248613Sdes u_char buf[8192]; 111248613Sdes size_t total; 112248613Sdes ssize_t r, s, o; 113248613Sdes struct modification mods[MAX_MODIFICATIONS]; 114248613Sdes u_int i, wflag = 0, num_mods = 0; 115248613Sdes 116248613Sdes while ((ch = getopt(argc, argv, "wm:")) != -1) { 117248613Sdes switch (ch) { 118248613Sdes case 'm': 119248613Sdes if (num_mods >= MAX_MODIFICATIONS) 120248613Sdes errx(1, "Too many modifications"); 121248613Sdes parse_modification(optarg, &(mods[num_mods++])); 122248613Sdes break; 123248613Sdes case 'w': 124248613Sdes wflag = 1; 125248613Sdes break; 126248613Sdes default: 127248613Sdes usage(); 128248613Sdes /* NOTREACHED */ 129248613Sdes } 130248613Sdes } 131248613Sdes for (total = 0;;) { 132248613Sdes r = s = read(STDIN_FILENO, buf, sizeof(buf)); 133248613Sdes if (r == 0) 134248613Sdes break; 135248613Sdes if (r < 0) { 136248613Sdes if (errno == EAGAIN || errno == EINTR) 137248613Sdes continue; 138248613Sdes err(1, "read"); 139248613Sdes } 140248613Sdes for (i = 0; i < num_mods; i++) { 141248613Sdes if (mods[i].offset < total || 142248613Sdes mods[i].offset >= total + s) 143248613Sdes continue; 144248613Sdes switch (mods[i].what) { 145248613Sdes case MOD_XOR: 146248613Sdes buf[mods[i].offset - total] ^= mods[i].m1; 147248613Sdes break; 148248613Sdes case MOD_AND_OR: 149248613Sdes buf[mods[i].offset - total] &= mods[i].m1; 150248613Sdes buf[mods[i].offset - total] |= mods[i].m2; 151248613Sdes break; 152248613Sdes } 153248613Sdes } 154248613Sdes for (o = 0; o < s; o += r) { 155248613Sdes r = write(STDOUT_FILENO, buf, s - o); 156248613Sdes if (r == 0) 157248613Sdes break; 158248613Sdes if (r < 0) { 159248613Sdes if (errno == EAGAIN || errno == EINTR) 160248613Sdes continue; 161248613Sdes err(1, "write"); 162248613Sdes } 163248613Sdes } 164248613Sdes total += s; 165248613Sdes } 166248613Sdes /* Warn if modifications not reached in input stream */ 167248613Sdes r = 0; 168248613Sdes for (i = 0; wflag && i < num_mods; i++) { 169248613Sdes if (mods[i].offset < total) 170248613Sdes continue; 171248613Sdes r = 1; 172248613Sdes fprintf(stderr, "modpipe: warning - mod %u not reached\n", i); 173248613Sdes } 174248613Sdes return r; 175248613Sdes} 176