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 <sys/types.h>
32 #include <errno.h>
33 #include <ctype.h>
34 #include <limits.h>
35 #include <string.h>
36 #include <stdlib.h>
37 #include <vis.h>
38 
39 #define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
40 #define	isvisible(c,flag)						\
41 	(((c) == '\\' || (flag & VIS_ALL) == 0) &&			\
42 	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
43 	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
44 		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
45 	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
46 	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
47 	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
48 	((flag & VIS_SAFE) && ((c) == '\b' ||				\
49 		(c) == '\007' || (c) == '\r' ||				\
50 		isgraph((u_char)(c))))))
51 
52 /*
53  * vis - visually encode characters
54  */
55 char *
vis(char * dst,int c,int flag,int nextc)56 vis(char *dst, int c, int flag, int nextc)
57 {
58 	if (isvisible(c, flag)) {
59 		if ((c == '"' && (flag & VIS_DQ) != 0) ||
60 		    (c == '\\' && (flag & VIS_NOSLASH) == 0))
61 			*dst++ = '\\';
62 		*dst++ = c;
63 		*dst = '\0';
64 		return (dst);
65 	}
66 
67 	if (flag & VIS_CSTYLE) {
68 		switch(c) {
69 		case '\n':
70 			*dst++ = '\\';
71 			*dst++ = 'n';
72 			goto done;
73 		case '\r':
74 			*dst++ = '\\';
75 			*dst++ = 'r';
76 			goto done;
77 		case '\b':
78 			*dst++ = '\\';
79 			*dst++ = 'b';
80 			goto done;
81 		case '\a':
82 			*dst++ = '\\';
83 			*dst++ = 'a';
84 			goto done;
85 		case '\v':
86 			*dst++ = '\\';
87 			*dst++ = 'v';
88 			goto done;
89 		case '\t':
90 			*dst++ = '\\';
91 			*dst++ = 't';
92 			goto done;
93 		case '\f':
94 			*dst++ = '\\';
95 			*dst++ = 'f';
96 			goto done;
97 		case ' ':
98 			*dst++ = '\\';
99 			*dst++ = 's';
100 			goto done;
101 		case '\0':
102 			*dst++ = '\\';
103 			*dst++ = '0';
104 			if (isoctal(nextc)) {
105 				*dst++ = '0';
106 				*dst++ = '0';
107 			}
108 			goto done;
109 		}
110 	}
111 	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
112 	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
113 		*dst++ = '\\';
114 		*dst++ = ((u_char)c >> 6 & 07) + '0';
115 		*dst++ = ((u_char)c >> 3 & 07) + '0';
116 		*dst++ = ((u_char)c & 07) + '0';
117 		goto done;
118 	}
119 	if ((flag & VIS_NOSLASH) == 0)
120 		*dst++ = '\\';
121 	if (c & 0200) {
122 		c &= 0177;
123 		*dst++ = 'M';
124 	}
125 	if (iscntrl((u_char)c)) {
126 		*dst++ = '^';
127 		if (c == 0177)
128 			*dst++ = '?';
129 		else
130 			*dst++ = c + '@';
131 	} else {
132 		*dst++ = '-';
133 		*dst++ = c;
134 	}
135 done:
136 	*dst = '\0';
137 	return (dst);
138 }
139 DEF_WEAK(vis);
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
strvis(char * dst,const char * src,int flag)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 DEF_WEAK(strvis);
166 
167 int
strnvis(char * dst,const char * src,size_t siz,int flag)168 strnvis(char *dst, const char *src, size_t siz, int flag)
169 {
170 	char *start, *end;
171 	char tbuf[5];
172 	int c, i;
173 
174 	i = 0;
175 	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
176 		if (isvisible(c, flag)) {
177 			if ((c == '"' && (flag & VIS_DQ) != 0) ||
178 			    (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
179 				/* need space for the extra '\\' */
180 				if (dst + 1 >= end) {
181 					i = 2;
182 					break;
183 				}
184 				*dst++ = '\\';
185 			}
186 			i = 1;
187 			*dst++ = c;
188 			src++;
189 		} else {
190 			i = vis(tbuf, c, flag, *++src) - tbuf;
191 			if (dst + i <= end) {
192 				memcpy(dst, tbuf, i);
193 				dst += i;
194 			} else {
195 				src--;
196 				break;
197 			}
198 		}
199 	}
200 	if (siz > 0)
201 		*dst = '\0';
202 	if (dst + i > end) {
203 		/* adjust return value for truncation */
204 		while ((c = *src))
205 			dst += vis(tbuf, c, flag, *++src) - tbuf;
206 	}
207 	return (dst - start);
208 }
209 
210 int
stravis(char ** outp,const char * src,int flag)211 stravis(char **outp, const char *src, int flag)
212 {
213 	char *buf;
214 	int len, serrno;
215 
216 	buf = reallocarray(NULL, 4, strlen(src) + 1);
217 	if (buf == NULL)
218 		return -1;
219 	len = strvis(buf, src, flag);
220 	serrno = errno;
221 	*outp = realloc(buf, len + 1);
222 	if (*outp == NULL) {
223 		*outp = buf;
224 		errno = serrno;
225 	}
226 	return (len);
227 }
228 
229 int
strvisx(char * dst,const char * src,size_t len,int flag)230 strvisx(char *dst, const char *src, size_t len, int flag)
231 {
232 	char c;
233 	char *start;
234 
235 	for (start = dst; len > 1; len--) {
236 		c = *src;
237 		dst = vis(dst, c, flag, *++src);
238 	}
239 	if (len)
240 		dst = vis(dst, *src, flag, '\0');
241 	*dst = '\0';
242 	return (dst - start);
243 }
244