xref: /openssh-portable/openbsd-compat/vis.c (revision 032147b6)
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 /* OPENBSD ORIGINAL: lib/libc/gen/vis.c */
32 
33 #include "includes.h"
34 #if !defined(HAVE_STRNVIS) || defined(BROKEN_STRNVIS)
35 
36 #include <sys/types.h>
37 #include <errno.h>
38 #include <ctype.h>
39 #include <limits.h>
40 #include <string.h>
41 #include <stdlib.h>
42 
43 #include "vis.h"
44 
45 #define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
46 #define	isvisible(c,flag)						\
47 	(((c) == '\\' || (flag & VIS_ALL) == 0) &&			\
48 	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
49 	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
50 		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
51 	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
52 	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
53 	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
54 	((flag & VIS_SAFE) && ((c) == '\b' ||				\
55 		(c) == '\007' || (c) == '\r' ||				\
56 		isgraph((u_char)(c))))))
57 
58 /*
59  * vis - visually encode characters
60  */
61 char *
vis(char * dst,int c,int flag,int nextc)62 vis(char *dst, int c, int flag, int nextc)
63 {
64 	if (isvisible(c, flag)) {
65 		if ((c == '"' && (flag & VIS_DQ) != 0) ||
66 		    (c == '\\' && (flag & VIS_NOSLASH) == 0))
67 			*dst++ = '\\';
68 		*dst++ = c;
69 		*dst = '\0';
70 		return (dst);
71 	}
72 
73 	if (flag & VIS_CSTYLE) {
74 		switch(c) {
75 		case '\n':
76 			*dst++ = '\\';
77 			*dst++ = 'n';
78 			goto done;
79 		case '\r':
80 			*dst++ = '\\';
81 			*dst++ = 'r';
82 			goto done;
83 		case '\b':
84 			*dst++ = '\\';
85 			*dst++ = 'b';
86 			goto done;
87 		case '\a':
88 			*dst++ = '\\';
89 			*dst++ = 'a';
90 			goto done;
91 		case '\v':
92 			*dst++ = '\\';
93 			*dst++ = 'v';
94 			goto done;
95 		case '\t':
96 			*dst++ = '\\';
97 			*dst++ = 't';
98 			goto done;
99 		case '\f':
100 			*dst++ = '\\';
101 			*dst++ = 'f';
102 			goto done;
103 		case ' ':
104 			*dst++ = '\\';
105 			*dst++ = 's';
106 			goto done;
107 		case '\0':
108 			*dst++ = '\\';
109 			*dst++ = '0';
110 			if (isoctal(nextc)) {
111 				*dst++ = '0';
112 				*dst++ = '0';
113 			}
114 			goto done;
115 		}
116 	}
117 	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
118 	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
119 		*dst++ = '\\';
120 		*dst++ = ((u_char)c >> 6 & 07) + '0';
121 		*dst++ = ((u_char)c >> 3 & 07) + '0';
122 		*dst++ = ((u_char)c & 07) + '0';
123 		goto done;
124 	}
125 	if ((flag & VIS_NOSLASH) == 0)
126 		*dst++ = '\\';
127 	if (c & 0200) {
128 		c &= 0177;
129 		*dst++ = 'M';
130 	}
131 	if (iscntrl((u_char)c)) {
132 		*dst++ = '^';
133 		if (c == 0177)
134 			*dst++ = '?';
135 		else
136 			*dst++ = c + '@';
137 	} else {
138 		*dst++ = '-';
139 		*dst++ = c;
140 	}
141 done:
142 	*dst = '\0';
143 	return (dst);
144 }
145 DEF_WEAK(vis);
146 
147 /*
148  * strvis, strnvis, strvisx - visually encode characters from src into dst
149  *
150  *	Dst must be 4 times the size of src to account for possible
151  *	expansion.  The length of dst, not including the trailing NULL,
152  *	is returned.
153  *
154  *	Strnvis will write no more than siz-1 bytes (and will NULL terminate).
155  *	The number of bytes needed to fully encode the string is returned.
156  *
157  *	Strvisx encodes exactly len bytes from src into dst.
158  *	This is useful for encoding a block of data.
159  */
160 int
strvis(char * dst,const char * src,int flag)161 strvis(char *dst, const char *src, int flag)
162 {
163 	char c;
164 	char *start;
165 
166 	for (start = dst; (c = *src);)
167 		dst = vis(dst, c, flag, *++src);
168 	*dst = '\0';
169 	return (dst - start);
170 }
171 DEF_WEAK(strvis);
172 
173 int
strnvis(char * dst,const char * src,size_t siz,int flag)174 strnvis(char *dst, const char *src, size_t siz, int flag)
175 {
176 	char *start, *end;
177 	char tbuf[5];
178 	int c, i;
179 
180 	i = 0;
181 	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
182 		if (isvisible(c, flag)) {
183 			if ((c == '"' && (flag & VIS_DQ) != 0) ||
184 			    (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
185 				/* need space for the extra '\\' */
186 				if (dst + 1 >= end) {
187 					i = 2;
188 					break;
189 				}
190 				*dst++ = '\\';
191 			}
192 			i = 1;
193 			*dst++ = c;
194 			src++;
195 		} else {
196 			i = vis(tbuf, c, flag, *++src) - tbuf;
197 			if (dst + i <= end) {
198 				memcpy(dst, tbuf, i);
199 				dst += i;
200 			} else {
201 				src--;
202 				break;
203 			}
204 		}
205 	}
206 	if (siz > 0)
207 		*dst = '\0';
208 	if (dst + i > end) {
209 		/* adjust return value for truncation */
210 		while ((c = *src))
211 			dst += vis(tbuf, c, flag, *++src) - tbuf;
212 	}
213 	return (dst - start);
214 }
215 
216 int
stravis(char ** outp,const char * src,int flag)217 stravis(char **outp, const char *src, int flag)
218 {
219 	char *buf;
220 	int len, serrno;
221 
222 	buf = reallocarray(NULL, 4, strlen(src) + 1);
223 	if (buf == NULL)
224 		return -1;
225 	len = strvis(buf, src, flag);
226 	serrno = errno;
227 	*outp = realloc(buf, len + 1);
228 	if (*outp == NULL) {
229 		*outp = buf;
230 		errno = serrno;
231 	}
232 	return (len);
233 }
234 
235 int
strvisx(char * dst,const char * src,size_t len,int flag)236 strvisx(char *dst, const char *src, size_t len, int flag)
237 {
238 	char c;
239 	char *start;
240 
241 	for (start = dst; len > 1; len--) {
242 		c = *src;
243 		dst = vis(dst, c, flag, *++src);
244 	}
245 	if (len)
246 		dst = vis(dst, *src, flag, '\0');
247 	*dst = '\0';
248 	return (dst - start);
249 }
250 
251 #endif
252