1 /*	$OpenBSD: vis.c,v 1.25 2015/09/13 11:32:51 guenther Exp $ */
2 /*-
3  * Copyright (c) 1989, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. Neither the name of the University nor the names of its contributors
15  *    may be used to endorse or promote products derived from this software
16  *    without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include "compat.h"
32 
33 #include <sys/types.h>
34 #include <errno.h>
35 #include <ctype.h>
36 #include <limits.h>
37 #include <string.h>
38 #include <stdlib.h>
39 
40 #define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
41 #define	isvisible(c,flag)						\
42 	(((c) == '\\' || (flag & VIS_ALL) == 0) &&			\
43 	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
44 	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
45 		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
46 	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
47 	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
48 	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
49 	((flag & VIS_SAFE) && ((c) == '\b' ||				\
50 		(c) == '\007' || (c) == '\r' ||				\
51 		isgraph((u_char)(c))))))
52 
53 /*
54  * vis - visually encode characters
55  */
56 char *
57 vis(char *dst, int c, int flag, int nextc)
58 {
59 	if (isvisible(c, flag)) {
60 		if ((c == '"' && (flag & VIS_DQ) != 0) ||
61 		    (c == '\\' && (flag & VIS_NOSLASH) == 0))
62 			*dst++ = '\\';
63 		*dst++ = c;
64 		*dst = '\0';
65 		return (dst);
66 	}
67 
68 	if (flag & VIS_CSTYLE) {
69 		switch(c) {
70 		case '\n':
71 			*dst++ = '\\';
72 			*dst++ = 'n';
73 			goto done;
74 		case '\r':
75 			*dst++ = '\\';
76 			*dst++ = 'r';
77 			goto done;
78 		case '\b':
79 			*dst++ = '\\';
80 			*dst++ = 'b';
81 			goto done;
82 		case '\a':
83 			*dst++ = '\\';
84 			*dst++ = 'a';
85 			goto done;
86 		case '\v':
87 			*dst++ = '\\';
88 			*dst++ = 'v';
89 			goto done;
90 		case '\t':
91 			*dst++ = '\\';
92 			*dst++ = 't';
93 			goto done;
94 		case '\f':
95 			*dst++ = '\\';
96 			*dst++ = 'f';
97 			goto done;
98 		case ' ':
99 			*dst++ = '\\';
100 			*dst++ = 's';
101 			goto done;
102 		case '\0':
103 			*dst++ = '\\';
104 			*dst++ = '0';
105 			if (isoctal(nextc)) {
106 				*dst++ = '0';
107 				*dst++ = '0';
108 			}
109 			goto done;
110 		}
111 	}
112 	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
113 	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
114 		*dst++ = '\\';
115 		*dst++ = ((u_char)c >> 6 & 07) + '0';
116 		*dst++ = ((u_char)c >> 3 & 07) + '0';
117 		*dst++ = ((u_char)c & 07) + '0';
118 		goto done;
119 	}
120 	if ((flag & VIS_NOSLASH) == 0)
121 		*dst++ = '\\';
122 	if (c & 0200) {
123 		c &= 0177;
124 		*dst++ = 'M';
125 	}
126 	if (iscntrl((u_char)c)) {
127 		*dst++ = '^';
128 		if (c == 0177)
129 			*dst++ = '?';
130 		else
131 			*dst++ = c + '@';
132 	} else {
133 		*dst++ = '-';
134 		*dst++ = c;
135 	}
136 done:
137 	*dst = '\0';
138 	return (dst);
139 }
140 
141 /*
142  * strvis, strnvis, strvisx - visually encode characters from src into dst
143  *	
144  *	Dst must be 4 times the size of src to account for possible
145  *	expansion.  The length of dst, not including the trailing NULL,
146  *	is returned. 
147  *
148  *	Strnvis will write no more than siz-1 bytes (and will NULL terminate).
149  *	The number of bytes needed to fully encode the string is returned.
150  *
151  *	Strvisx encodes exactly len bytes from src into dst.
152  *	This is useful for encoding a block of data.
153  */
154 int
155 strvis(char *dst, const char *src, int flag)
156 {
157 	char c;
158 	char *start;
159 
160 	for (start = dst; (c = *src);)
161 		dst = vis(dst, c, flag, *++src);
162 	*dst = '\0';
163 	return (dst - start);
164 }
165 
166 int
167 strnvis(char *dst, const char *src, size_t siz, int flag)
168 {
169 	char *start, *end;
170 	char tbuf[5];
171 	int c, i;
172 
173 	i = 0;
174 	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
175 		if (isvisible(c, flag)) {
176 			if ((c == '"' && (flag & VIS_DQ) != 0) ||
177 			    (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
178 				/* need space for the extra '\\' */
179 				if (dst + 1 >= end) {
180 					i = 2;
181 					break;
182 				}
183 				*dst++ = '\\';
184 			}
185 			i = 1;
186 			*dst++ = c;
187 			src++;
188 		} else {
189 			i = vis(tbuf, c, flag, *++src) - tbuf;
190 			if (dst + i <= end) {
191 				memcpy(dst, tbuf, i);
192 				dst += i;
193 			} else {
194 				src--;
195 				break;
196 			}
197 		}
198 	}
199 	if (siz > 0)
200 		*dst = '\0';
201 	if (dst + i > end) {
202 		/* adjust return value for truncation */
203 		while ((c = *src))
204 			dst += vis(tbuf, c, flag, *++src) - tbuf;
205 	}
206 	return (dst - start);
207 }
208 
209 int
210 stravis(char **outp, const char *src, int flag)
211 {
212 	char *buf;
213 	int len, serrno;
214 
215 	buf = reallocarray(NULL, 4, strlen(src) + 1);
216 	if (buf == NULL)
217 		return -1;
218 	len = strvis(buf, src, flag);
219 	serrno = errno;
220 	*outp = realloc(buf, len + 1);
221 	if (*outp == NULL) {
222 		*outp = buf;
223 		errno = serrno;
224 	}
225 	return (len);
226 }
227 
228 int
229 strvisx(char *dst, const char *src, size_t len, int flag)
230 {
231 	char c;
232 	char *start;
233 
234 	for (start = dst; len > 1; len--) {
235 		c = *src;
236 		dst = vis(dst, c, flag, *++src);
237 	}
238 	if (len)
239 		dst = vis(dst, *src, flag, '\0');
240 	*dst = '\0';
241 	return (dst - start);
242 }