xref: /freebsd/crypto/openssh/regress/modpipe.c (revision de7b456e596ff18032d2cbfdf244c66f36770da4)
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 1.5 2013/05/10 03:46:14 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 #include "openbsd-compat/getopt_long.c"
29 
30 static void err(int, const char *, ...) __attribute__((format(printf, 2, 3)));
31 static void errx(int, const char *, ...) __attribute__((format(printf, 2, 3)));
32 
33 static void
34 err(int r, const char *fmt, ...)
35 {
36 	va_list args;
37 
38 	va_start(args, fmt);
39 	fprintf(stderr, "%s: ", strerror(errno));
40 	vfprintf(stderr, fmt, args);
41 	fputc('\n', stderr);
42 	va_end(args);
43 	exit(r);
44 }
45 
46 static void
47 errx(int r, const char *fmt, ...)
48 {
49 	va_list args;
50 
51 	va_start(args, fmt);
52 	vfprintf(stderr, fmt, args);
53 	fputc('\n', stderr);
54 	va_end(args);
55 	exit(r);
56 }
57 
58 static void
59 usage(void)
60 {
61 	fprintf(stderr, "Usage: modpipe -w [-m modspec ...] < in > out\n");
62 	fprintf(stderr, "modspec is one of:\n");
63 	fprintf(stderr, "    xor:offset:value       - XOR \"value\" at \"offset\"\n");
64 	fprintf(stderr, "    andor:offset:val1:val2 - AND \"val1\" then OR \"val2\" at \"offset\"\n");
65 	exit(1);
66 }
67 
68 #define MAX_MODIFICATIONS 256
69 struct modification {
70 	enum { MOD_XOR, MOD_AND_OR } what;
71 	u_int64_t offset;
72 	u_int8_t m1, m2;
73 };
74 
75 static void
76 parse_modification(const char *s, struct modification *m)
77 {
78 	char what[16+1];
79 	int n, m1, m2;
80 
81 	bzero(m, sizeof(*m));
82 	if ((n = sscanf(s, "%16[^:]%*[:]%lli%*[:]%i%*[:]%i",
83 	    what, &m->offset, &m1, &m2)) < 3)
84 		errx(1, "Invalid modification spec \"%s\"", s);
85 	if (strcasecmp(what, "xor") == 0) {
86 		if (n > 3)
87 			errx(1, "Invalid modification spec \"%s\"", s);
88 		if (m1 < 0 || m1 > 0xff)
89 			errx(1, "Invalid XOR modification value");
90 		m->what = MOD_XOR;
91 		m->m1 = m1;
92 	} else if (strcasecmp(what, "andor") == 0) {
93 		if (n != 4)
94 			errx(1, "Invalid modification spec \"%s\"", s);
95 		if (m1 < 0 || m1 > 0xff)
96 			errx(1, "Invalid AND modification value");
97 		if (m2 < 0 || m2 > 0xff)
98 			errx(1, "Invalid OR modification value");
99 		m->what = MOD_AND_OR;
100 		m->m1 = m1;
101 		m->m2 = m2;
102 	} else
103 		errx(1, "Invalid modification type \"%s\"", what);
104 }
105 
106 int
107 main(int argc, char **argv)
108 {
109 	int ch;
110 	u_char buf[8192];
111 	size_t total;
112 	ssize_t r, s, o;
113 	struct modification mods[MAX_MODIFICATIONS];
114 	u_int i, wflag = 0, num_mods = 0;
115 
116 	while ((ch = getopt(argc, argv, "wm:")) != -1) {
117 		switch (ch) {
118 		case 'm':
119 			if (num_mods >= MAX_MODIFICATIONS)
120 				errx(1, "Too many modifications");
121 			parse_modification(optarg, &(mods[num_mods++]));
122 			break;
123 		case 'w':
124 			wflag = 1;
125 			break;
126 		default:
127 			usage();
128 			/* NOTREACHED */
129 		}
130 	}
131 	for (total = 0;;) {
132 		r = s = read(STDIN_FILENO, buf, sizeof(buf));
133 		if (r == 0)
134 			break;
135 		if (r < 0) {
136 			if (errno == EAGAIN || errno == EINTR)
137 				continue;
138 			err(1, "read");
139 		}
140 		for (i = 0; i < num_mods; i++) {
141 			if (mods[i].offset < total ||
142 			    mods[i].offset >= total + s)
143 				continue;
144 			switch (mods[i].what) {
145 			case MOD_XOR:
146 				buf[mods[i].offset - total] ^= mods[i].m1;
147 				break;
148 			case MOD_AND_OR:
149 				buf[mods[i].offset - total] &= mods[i].m1;
150 				buf[mods[i].offset - total] |= mods[i].m2;
151 				break;
152 			}
153 		}
154 		for (o = 0; o < s; o += r) {
155 			r = write(STDOUT_FILENO, buf, s - o);
156 			if (r == 0)
157 				break;
158 			if (r < 0) {
159 				if (errno == EAGAIN || errno == EINTR)
160 					continue;
161 				err(1, "write");
162 			}
163 		}
164 		total += s;
165 	}
166 	/* Warn if modifications not reached in input stream */
167 	r = 0;
168 	for (i = 0; wflag && i < num_mods; i++) {
169 		if (mods[i].offset < total)
170 			continue;
171 		r = 1;
172 		fprintf(stderr, "modpipe: warning - mod %u not reached\n", i);
173 	}
174 	return r;
175 }
176