vis.c revision 323129 
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/*
37 * We want these to override in the BROKEN_STRNVIS case.  TO avoid future sync
38 * problems no-op out the weak symbol definition rather than remove it.
39 */
40#define DEF_WEAK(x)
41
42#include <sys/types.h>
43#include <errno.h>
44#include <ctype.h>
45#include <limits.h>
46#include <string.h>
47#include <stdlib.h>
48
49#include "vis.h"
50
51#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
52#define	isvisible(c,flag)						\
53	(((c) == '\\' || (flag & VIS_ALL) == 0) &&			\
54	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
55	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
56		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
57	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
58	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
59	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
60	((flag & VIS_SAFE) && ((c) == '\b' ||				\
61		(c) == '\007' || (c) == '\r' ||				\
62		isgraph((u_char)(c))))))
63
64/*
65 * vis - visually encode characters
66 */
67char *
68vis(char *dst, int c, int flag, int nextc)
69{
70	if (isvisible(c, flag)) {
71		if ((c == '"' && (flag & VIS_DQ) != 0) ||
72		    (c == '\\' && (flag & VIS_NOSLASH) == 0))
73			*dst++ = '\\';
74		*dst++ = c;
75		*dst = '\0';
76		return (dst);
77	}
78
79	if (flag & VIS_CSTYLE) {
80		switch(c) {
81		case '\n':
82			*dst++ = '\\';
83			*dst++ = 'n';
84			goto done;
85		case '\r':
86			*dst++ = '\\';
87			*dst++ = 'r';
88			goto done;
89		case '\b':
90			*dst++ = '\\';
91			*dst++ = 'b';
92			goto done;
93		case '\a':
94			*dst++ = '\\';
95			*dst++ = 'a';
96			goto done;
97		case '\v':
98			*dst++ = '\\';
99			*dst++ = 'v';
100			goto done;
101		case '\t':
102			*dst++ = '\\';
103			*dst++ = 't';
104			goto done;
105		case '\f':
106			*dst++ = '\\';
107			*dst++ = 'f';
108			goto done;
109		case ' ':
110			*dst++ = '\\';
111			*dst++ = 's';
112			goto done;
113		case '\0':
114			*dst++ = '\\';
115			*dst++ = '0';
116			if (isoctal(nextc)) {
117				*dst++ = '0';
118				*dst++ = '0';
119			}
120			goto done;
121		}
122	}
123	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
124	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
125		*dst++ = '\\';
126		*dst++ = ((u_char)c >> 6 & 07) + '0';
127		*dst++ = ((u_char)c >> 3 & 07) + '0';
128		*dst++ = ((u_char)c & 07) + '0';
129		goto done;
130	}
131	if ((flag & VIS_NOSLASH) == 0)
132		*dst++ = '\\';
133	if (c & 0200) {
134		c &= 0177;
135		*dst++ = 'M';
136	}
137	if (iscntrl((u_char)c)) {
138		*dst++ = '^';
139		if (c == 0177)
140			*dst++ = '?';
141		else
142			*dst++ = c + '@';
143	} else {
144		*dst++ = '-';
145		*dst++ = c;
146	}
147done:
148	*dst = '\0';
149	return (dst);
150}
151DEF_WEAK(vis);
152
153/*
154 * strvis, strnvis, strvisx - visually encode characters from src into dst
155 *
156 *	Dst must be 4 times the size of src to account for possible
157 *	expansion.  The length of dst, not including the trailing NULL,
158 *	is returned.
159 *
160 *	Strnvis will write no more than siz-1 bytes (and will NULL terminate).
161 *	The number of bytes needed to fully encode the string is returned.
162 *
163 *	Strvisx encodes exactly len bytes from src into dst.
164 *	This is useful for encoding a block of data.
165 */
166int
167strvis(char *dst, const char *src, int flag)
168{
169	char c;
170	char *start;
171
172	for (start = dst; (c = *src);)
173		dst = vis(dst, c, flag, *++src);
174	*dst = '\0';
175	return (dst - start);
176}
177DEF_WEAK(strvis);
178
179int
180strnvis(char *dst, const char *src, size_t siz, int flag)
181{
182	char *start, *end;
183	char tbuf[5];
184	int c, i;
185
186	i = 0;
187	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
188		if (isvisible(c, flag)) {
189			if ((c == '"' && (flag & VIS_DQ) != 0) ||
190			    (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
191				/* need space for the extra '\\' */
192				if (dst + 1 >= end) {
193					i = 2;
194					break;
195				}
196				*dst++ = '\\';
197			}
198			i = 1;
199			*dst++ = c;
200			src++;
201		} else {
202			i = vis(tbuf, c, flag, *++src) - tbuf;
203			if (dst + i <= end) {
204				memcpy(dst, tbuf, i);
205				dst += i;
206			} else {
207				src--;
208				break;
209			}
210		}
211	}
212	if (siz > 0)
213		*dst = '\0';
214	if (dst + i > end) {
215		/* adjust return value for truncation */
216		while ((c = *src))
217			dst += vis(tbuf, c, flag, *++src) - tbuf;
218	}
219	return (dst - start);
220}
221
222int
223stravis(char **outp, const char *src, int flag)
224{
225	char *buf;
226	int len, serrno;
227
228	buf = reallocarray(NULL, 4, strlen(src) + 1);
229	if (buf == NULL)
230		return -1;
231	len = strvis(buf, src, flag);
232	serrno = errno;
233	*outp = realloc(buf, len + 1);
234	if (*outp == NULL) {
235		*outp = buf;
236		errno = serrno;
237	}
238	return (len);
239}
240
241int
242strvisx(char *dst, const char *src, size_t len, int flag)
243{
244	char c;
245	char *start;
246
247	for (start = dst; len > 1; len--) {
248		c = *src;
249		dst = vis(dst, c, flag, *++src);
250	}
251	if (len)
252		dst = vis(dst, *src, flag, '\0');
253	*dst = '\0';
254	return (dst - start);
255}
256
257#endif
258