1 /* $OpenBSD: unvis.c,v 1.17 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 <ctype.h>
33 #include <vis.h>
34
35 /*
36 * decode driven by state machine
37 */
38 #define S_GROUND 0 /* haven't seen escape char */
39 #define S_START 1 /* start decoding special sequence */
40 #define S_META 2 /* metachar started (M) */
41 #define S_META1 3 /* metachar more, regular char (-) */
42 #define S_CTRL 4 /* control char started (^) */
43 #define S_OCTAL2 5 /* octal digit 2 */
44 #define S_OCTAL3 6 /* octal digit 3 */
45
46 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
47
48 /*
49 * unvis - decode characters previously encoded by vis
50 */
51 int
unvis(char * cp,char c,int * astate,int flag)52 unvis(char *cp, char c, int *astate, int flag)
53 {
54
55 if (flag & UNVIS_END) {
56 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
57 *astate = S_GROUND;
58 return (UNVIS_VALID);
59 }
60 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
61 }
62
63 switch (*astate) {
64
65 case S_GROUND:
66 *cp = 0;
67 if (c == '\\') {
68 *astate = S_START;
69 return (0);
70 }
71 *cp = c;
72 return (UNVIS_VALID);
73
74 case S_START:
75 switch(c) {
76 case '-':
77 *cp = 0;
78 *astate = S_GROUND;
79 return (0);
80 case '\\':
81 case '"':
82 *cp = c;
83 *astate = S_GROUND;
84 return (UNVIS_VALID);
85 case '0': case '1': case '2': case '3':
86 case '4': case '5': case '6': case '7':
87 *cp = (c - '0');
88 *astate = S_OCTAL2;
89 return (0);
90 case 'M':
91 *cp = (char) 0200;
92 *astate = S_META;
93 return (0);
94 case '^':
95 *astate = S_CTRL;
96 return (0);
97 case 'n':
98 *cp = '\n';
99 *astate = S_GROUND;
100 return (UNVIS_VALID);
101 case 'r':
102 *cp = '\r';
103 *astate = S_GROUND;
104 return (UNVIS_VALID);
105 case 'b':
106 *cp = '\b';
107 *astate = S_GROUND;
108 return (UNVIS_VALID);
109 case 'a':
110 *cp = '\007';
111 *astate = S_GROUND;
112 return (UNVIS_VALID);
113 case 'v':
114 *cp = '\v';
115 *astate = S_GROUND;
116 return (UNVIS_VALID);
117 case 't':
118 *cp = '\t';
119 *astate = S_GROUND;
120 return (UNVIS_VALID);
121 case 'f':
122 *cp = '\f';
123 *astate = S_GROUND;
124 return (UNVIS_VALID);
125 case 's':
126 *cp = ' ';
127 *astate = S_GROUND;
128 return (UNVIS_VALID);
129 case 'E':
130 *cp = '\033';
131 *astate = S_GROUND;
132 return (UNVIS_VALID);
133 case '\n':
134 /*
135 * hidden newline
136 */
137 *astate = S_GROUND;
138 return (UNVIS_NOCHAR);
139 case '$':
140 /*
141 * hidden marker
142 */
143 *astate = S_GROUND;
144 return (UNVIS_NOCHAR);
145 }
146 *astate = S_GROUND;
147 return (UNVIS_SYNBAD);
148
149 case S_META:
150 if (c == '-')
151 *astate = S_META1;
152 else if (c == '^')
153 *astate = S_CTRL;
154 else {
155 *astate = S_GROUND;
156 return (UNVIS_SYNBAD);
157 }
158 return (0);
159
160 case S_META1:
161 *astate = S_GROUND;
162 *cp |= c;
163 return (UNVIS_VALID);
164
165 case S_CTRL:
166 if (c == '?')
167 *cp |= 0177;
168 else
169 *cp |= c & 037;
170 *astate = S_GROUND;
171 return (UNVIS_VALID);
172
173 case S_OCTAL2: /* second possible octal digit */
174 if (isoctal(c)) {
175 /*
176 * yes - and maybe a third
177 */
178 *cp = (*cp << 3) + (c - '0');
179 *astate = S_OCTAL3;
180 return (0);
181 }
182 /*
183 * no - done with current sequence, push back passed char
184 */
185 *astate = S_GROUND;
186 return (UNVIS_VALIDPUSH);
187
188 case S_OCTAL3: /* third possible octal digit */
189 *astate = S_GROUND;
190 if (isoctal(c)) {
191 *cp = (*cp << 3) + (c - '0');
192 return (UNVIS_VALID);
193 }
194 /*
195 * we were done, push back passed char
196 */
197 return (UNVIS_VALIDPUSH);
198
199 default:
200 /*
201 * decoder in unknown state - (probably uninitialized)
202 */
203 *astate = S_GROUND;
204 return (UNVIS_SYNBAD);
205 }
206 }
207 DEF_WEAK(unvis);
208
209 /*
210 * strunvis - decode src into dst
211 *
212 * Number of chars decoded into dst is returned, -1 on error.
213 * Dst is null terminated.
214 */
215
216 int
strunvis(char * dst,const char * src)217 strunvis(char *dst, const char *src)
218 {
219 char c;
220 char *start = dst;
221 int state = 0;
222
223 while ((c = *src++)) {
224 again:
225 switch (unvis(dst, c, &state, 0)) {
226 case UNVIS_VALID:
227 dst++;
228 break;
229 case UNVIS_VALIDPUSH:
230 dst++;
231 goto again;
232 case 0:
233 case UNVIS_NOCHAR:
234 break;
235 default:
236 *dst = '\0';
237 return (-1);
238 }
239 }
240 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
241 dst++;
242 *dst = '\0';
243 return (dst - start);
244 }
245
246 ssize_t
strnunvis(char * dst,const char * src,size_t sz)247 strnunvis(char *dst, const char *src, size_t sz)
248 {
249 char c, p;
250 char *start = dst, *end = dst + sz - 1;
251 int state = 0;
252
253 if (sz > 0)
254 *end = '\0';
255 while ((c = *src++)) {
256 again:
257 switch (unvis(&p, c, &state, 0)) {
258 case UNVIS_VALID:
259 if (dst < end)
260 *dst = p;
261 dst++;
262 break;
263 case UNVIS_VALIDPUSH:
264 if (dst < end)
265 *dst = p;
266 dst++;
267 goto again;
268 case 0:
269 case UNVIS_NOCHAR:
270 break;
271 default:
272 if (dst <= end)
273 *dst = '\0';
274 return (-1);
275 }
276 }
277 if (unvis(&p, c, &state, UNVIS_END) == UNVIS_VALID) {
278 if (dst < end)
279 *dst = p;
280 dst++;
281 }
282 if (dst <= end)
283 *dst = '\0';
284 return (dst - start);
285 }
286
287