1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/*
* 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 1.6 2013/11/21 03:16:47 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>
#ifdef HAVE_ERR_H
# include <err.h>
#endif
#include "openbsd-compat/getopt_long.c"
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;
}
|
