151 lines
3.8 KiB
C
Executable File
151 lines
3.8 KiB
C
Executable File
/*
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* Copyright (c) 2012 Damien Miller <djm@mindrot.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/* $OpenBSD: modpipe.c,v 1.6 2013/11/21 03:16:47 djm Exp $ */
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#include "includes.h"
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <errno.h>
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#ifdef HAVE_ERR_H
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# include <err.h>
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#endif
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#include "openbsd-compat/getopt_long.c"
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static void
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usage(void)
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{
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fprintf(stderr, "Usage: modpipe -w [-m modspec ...] < in > out\n");
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fprintf(stderr, "modspec is one of:\n");
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fprintf(stderr, " xor:offset:value - XOR \"value\" at \"offset\"\n");
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fprintf(stderr, " andor:offset:val1:val2 - AND \"val1\" then OR \"val2\" at \"offset\"\n");
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exit(1);
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}
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#define MAX_MODIFICATIONS 256
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struct modification {
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enum { MOD_XOR, MOD_AND_OR } what;
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unsigned long long offset;
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u_int8_t m1, m2;
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};
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static void
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parse_modification(const char *s, struct modification *m)
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{
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char what[16+1];
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int n, m1, m2;
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bzero(m, sizeof(*m));
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if ((n = sscanf(s, "%16[^:]%*[:]%llu%*[:]%i%*[:]%i",
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what, &m->offset, &m1, &m2)) < 3)
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errx(1, "Invalid modification spec \"%s\"", s);
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if (strcasecmp(what, "xor") == 0) {
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if (n > 3)
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errx(1, "Invalid modification spec \"%s\"", s);
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if (m1 < 0 || m1 > 0xff)
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errx(1, "Invalid XOR modification value");
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m->what = MOD_XOR;
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m->m1 = m1;
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} else if (strcasecmp(what, "andor") == 0) {
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if (n != 4)
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errx(1, "Invalid modification spec \"%s\"", s);
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if (m1 < 0 || m1 > 0xff)
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errx(1, "Invalid AND modification value");
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if (m2 < 0 || m2 > 0xff)
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errx(1, "Invalid OR modification value");
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m->what = MOD_AND_OR;
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m->m1 = m1;
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m->m2 = m2;
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} else
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errx(1, "Invalid modification type \"%s\"", what);
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}
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int
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main(int argc, char **argv)
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{
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int ch;
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u_char buf[8192];
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size_t total;
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ssize_t r, s, o;
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struct modification mods[MAX_MODIFICATIONS];
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u_int i, wflag = 0, num_mods = 0;
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while ((ch = getopt(argc, argv, "wm:")) != -1) {
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switch (ch) {
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case 'm':
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if (num_mods >= MAX_MODIFICATIONS)
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errx(1, "Too many modifications");
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parse_modification(optarg, &(mods[num_mods++]));
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break;
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case 'w':
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wflag = 1;
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break;
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default:
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usage();
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/* NOTREACHED */
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}
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}
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for (total = 0;;) {
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r = s = read(STDIN_FILENO, buf, sizeof(buf));
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if (r == 0)
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break;
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if (r < 0) {
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if (errno == EAGAIN || errno == EINTR)
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continue;
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err(1, "read");
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}
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for (i = 0; i < num_mods; i++) {
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if (mods[i].offset < total ||
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mods[i].offset >= total + s)
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continue;
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switch (mods[i].what) {
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case MOD_XOR:
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buf[mods[i].offset - total] ^= mods[i].m1;
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break;
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case MOD_AND_OR:
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buf[mods[i].offset - total] &= mods[i].m1;
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buf[mods[i].offset - total] |= mods[i].m2;
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break;
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}
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}
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for (o = 0; o < s; o += r) {
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r = write(STDOUT_FILENO, buf, s - o);
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if (r == 0)
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break;
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if (r < 0) {
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if (errno == EAGAIN || errno == EINTR)
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continue;
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err(1, "write");
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}
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}
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total += s;
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}
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/* Warn if modifications not reached in input stream */
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r = 0;
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for (i = 0; wflag && i < num_mods; i++) {
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if (mods[i].offset < total)
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continue;
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r = 1;
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fprintf(stderr, "modpipe: warning - mod %u not reached\n", i);
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}
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return r;
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}
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