| /* |
| * Copyright (c) 2012 Damien Miller <djm@mindrot.org> |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| /* $OpenBSD: modpipe.c,v 1.5 2013/05/10 03:46:14 djm Exp $ */ |
| |
| #include "includes.h" |
| |
| #include <sys/types.h> |
| #include <unistd.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdarg.h> |
| #include <stdlib.h> |
| #include <errno.h> |
| #include "openbsd-compat/getopt_long.c" |
| |
| static void err(int, const char *, ...) __attribute__((format(printf, 2, 3))); |
| static void errx(int, const char *, ...) __attribute__((format(printf, 2, 3))); |
| |
| static void |
| err(int r, const char *fmt, ...) |
| { |
| va_list args; |
| |
| va_start(args, fmt); |
| fprintf(stderr, "%s: ", strerror(errno)); |
| vfprintf(stderr, fmt, args); |
| fputc('\n', stderr); |
| va_end(args); |
| exit(r); |
| } |
| |
| static void |
| errx(int r, const char *fmt, ...) |
| { |
| va_list args; |
| |
| va_start(args, fmt); |
| vfprintf(stderr, fmt, args); |
| fputc('\n', stderr); |
| va_end(args); |
| exit(r); |
| } |
| |
| static void |
| usage(void) |
| { |
| fprintf(stderr, "Usage: modpipe -w [-m modspec ...] < in > out\n"); |
| fprintf(stderr, "modspec is one of:\n"); |
| fprintf(stderr, " xor:offset:value - XOR \"value\" at \"offset\"\n"); |
| fprintf(stderr, " andor:offset:val1:val2 - AND \"val1\" then OR \"val2\" at \"offset\"\n"); |
| exit(1); |
| } |
| |
| #define MAX_MODIFICATIONS 256 |
| struct modification { |
| enum { MOD_XOR, MOD_AND_OR } what; |
| unsigned long long offset; |
| u_int8_t m1, m2; |
| }; |
| |
| static void |
| parse_modification(const char *s, struct modification *m) |
| { |
| char what[16+1]; |
| int n, m1, m2; |
| |
| bzero(m, sizeof(*m)); |
| if ((n = sscanf(s, "%16[^:]%*[:]%llu%*[:]%i%*[:]%i", |
| what, &m->offset, &m1, &m2)) < 3) |
| errx(1, "Invalid modification spec \"%s\"", s); |
| if (strcasecmp(what, "xor") == 0) { |
| if (n > 3) |
| errx(1, "Invalid modification spec \"%s\"", s); |
| if (m1 < 0 || m1 > 0xff) |
| errx(1, "Invalid XOR modification value"); |
| m->what = MOD_XOR; |
| m->m1 = m1; |
| } else if (strcasecmp(what, "andor") == 0) { |
| if (n != 4) |
| errx(1, "Invalid modification spec \"%s\"", s); |
| if (m1 < 0 || m1 > 0xff) |
| errx(1, "Invalid AND modification value"); |
| if (m2 < 0 || m2 > 0xff) |
| errx(1, "Invalid OR modification value"); |
| m->what = MOD_AND_OR; |
| m->m1 = m1; |
| m->m2 = m2; |
| } else |
| errx(1, "Invalid modification type \"%s\"", what); |
| } |
| |
| int |
| main(int argc, char **argv) |
| { |
| int ch; |
| u_char buf[8192]; |
| size_t total; |
| ssize_t r, s, o; |
| struct modification mods[MAX_MODIFICATIONS]; |
| u_int i, wflag = 0, num_mods = 0; |
| |
| while ((ch = getopt(argc, argv, "wm:")) != -1) { |
| switch (ch) { |
| case 'm': |
| if (num_mods >= MAX_MODIFICATIONS) |
| errx(1, "Too many modifications"); |
| parse_modification(optarg, &(mods[num_mods++])); |
| break; |
| case 'w': |
| wflag = 1; |
| break; |
| default: |
| usage(); |
| /* NOTREACHED */ |
| } |
| } |
| for (total = 0;;) { |
| r = s = read(STDIN_FILENO, buf, sizeof(buf)); |
| if (r == 0) |
| break; |
| if (r < 0) { |
| if (errno == EAGAIN || errno == EINTR) |
| continue; |
| err(1, "read"); |
| } |
| for (i = 0; i < num_mods; i++) { |
| if (mods[i].offset < total || |
| mods[i].offset >= total + s) |
| continue; |
| switch (mods[i].what) { |
| case MOD_XOR: |
| buf[mods[i].offset - total] ^= mods[i].m1; |
| break; |
| case MOD_AND_OR: |
| buf[mods[i].offset - total] &= mods[i].m1; |
| buf[mods[i].offset - total] |= mods[i].m2; |
| break; |
| } |
| } |
| for (o = 0; o < s; o += r) { |
| r = write(STDOUT_FILENO, buf, s - o); |
| if (r == 0) |
| break; |
| if (r < 0) { |
| if (errno == EAGAIN || errno == EINTR) |
| continue; |
| err(1, "write"); |
| } |
| } |
| total += s; |
| } |
| /* Warn if modifications not reached in input stream */ |
| r = 0; |
| for (i = 0; wflag && i < num_mods; i++) { |
| if (mods[i].offset < total) |
| continue; |
| r = 1; |
| fprintf(stderr, "modpipe: warning - mod %u not reached\n", i); |
| } |
| return r; |
| } |