xref: /openssh-portable/regress/modpipe.c (revision affa6ba6)
1 /*
2  * Copyright (c) 2012 Damien Miller <djm@mindrot.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /* $OpenBSD: modpipe.c,v 1.6 2013/11/21 03:16:47 djm Exp $ */
18 
19 #include "includes.h"
20 
21 #include <sys/types.h>
22 #include <unistd.h>
23 #include <stdio.h>
24 #include <string.h>
25 #include <stdarg.h>
26 #include <stdlib.h>
27 #include <errno.h>
28 #ifdef HAVE_ERR_H
29 # include <err.h>
30 #endif
31 #include "openbsd-compat/getopt_long.c"
32 
33 static void
usage(void)34 usage(void)
35 {
36 	fprintf(stderr, "Usage: modpipe -w [-m modspec ...] < in > out\n");
37 	fprintf(stderr, "modspec is one of:\n");
38 	fprintf(stderr, "    xor:offset:value       - XOR \"value\" at \"offset\"\n");
39 	fprintf(stderr, "    andor:offset:val1:val2 - AND \"val1\" then OR \"val2\" at \"offset\"\n");
40 	exit(1);
41 }
42 
43 #define MAX_MODIFICATIONS 256
44 struct modification {
45 	enum { MOD_XOR, MOD_AND_OR } what;
46 	unsigned long long offset;
47 	u_int8_t m1, m2;
48 };
49 
50 static void
parse_modification(const char * s,struct modification * m)51 parse_modification(const char *s, struct modification *m)
52 {
53 	char what[16+1];
54 	int n, m1, m2;
55 
56 	bzero(m, sizeof(*m));
57 	if ((n = sscanf(s, "%16[^:]%*[:]%llu%*[:]%i%*[:]%i",
58 	    what, &m->offset, &m1, &m2)) < 3)
59 		errx(1, "Invalid modification spec \"%s\"", s);
60 	if (strcasecmp(what, "xor") == 0) {
61 		if (n > 3)
62 			errx(1, "Invalid modification spec \"%s\"", s);
63 		if (m1 < 0 || m1 > 0xff)
64 			errx(1, "Invalid XOR modification value");
65 		m->what = MOD_XOR;
66 		m->m1 = m1;
67 	} else if (strcasecmp(what, "andor") == 0) {
68 		if (n != 4)
69 			errx(1, "Invalid modification spec \"%s\"", s);
70 		if (m1 < 0 || m1 > 0xff)
71 			errx(1, "Invalid AND modification value");
72 		if (m2 < 0 || m2 > 0xff)
73 			errx(1, "Invalid OR modification value");
74 		m->what = MOD_AND_OR;
75 		m->m1 = m1;
76 		m->m2 = m2;
77 	} else
78 		errx(1, "Invalid modification type \"%s\"", what);
79 }
80 
81 int
main(int argc,char ** argv)82 main(int argc, char **argv)
83 {
84 	int ch;
85 	u_char buf[8192];
86 	size_t total;
87 	ssize_t r, s, o;
88 	struct modification mods[MAX_MODIFICATIONS];
89 	u_int i, wflag = 0, num_mods = 0;
90 
91 	while ((ch = getopt(argc, argv, "wm:")) != -1) {
92 		switch (ch) {
93 		case 'm':
94 			if (num_mods >= MAX_MODIFICATIONS)
95 				errx(1, "Too many modifications");
96 			parse_modification(optarg, &(mods[num_mods++]));
97 			break;
98 		case 'w':
99 			wflag = 1;
100 			break;
101 		default:
102 			usage();
103 			/* NOTREACHED */
104 		}
105 	}
106 	for (total = 0;;) {
107 		r = s = read(STDIN_FILENO, buf, sizeof(buf));
108 		if (r == 0)
109 			break;
110 		if (r < 0) {
111 			if (errno == EAGAIN || errno == EINTR)
112 				continue;
113 			err(1, "read");
114 		}
115 		for (i = 0; i < num_mods; i++) {
116 			if (mods[i].offset < total ||
117 			    mods[i].offset >= total + s)
118 				continue;
119 			switch (mods[i].what) {
120 			case MOD_XOR:
121 				buf[mods[i].offset - total] ^= mods[i].m1;
122 				break;
123 			case MOD_AND_OR:
124 				buf[mods[i].offset - total] &= mods[i].m1;
125 				buf[mods[i].offset - total] |= mods[i].m2;
126 				break;
127 			}
128 		}
129 		for (o = 0; o < s; o += r) {
130 			r = write(STDOUT_FILENO, buf, s - o);
131 			if (r == 0)
132 				break;
133 			if (r < 0) {
134 				if (errno == EAGAIN || errno == EINTR)
135 					continue;
136 				err(1, "write");
137 			}
138 		}
139 		total += s;
140 	}
141 	/* Warn if modifications not reached in input stream */
142 	r = 0;
143 	for (i = 0; wflag && i < num_mods; i++) {
144 		if (mods[i].offset < total)
145 			continue;
146 		r = 1;
147 		fprintf(stderr, "modpipe: warning - mod %u not reached\n", i);
148 	}
149 	return r;
150 }
151