1 /* $OpenBSD: unvis.c,v 1.16 2015/07/20 01:52:28 millert 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 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 } 207 208 /* 209 * strunvis - decode src into dst 210 * 211 * Number of chars decoded into dst is returned, -1 on error. 212 * Dst is null terminated. 213 */ 214 215 int 216 strunvis(char *dst, const char *src) 217 { 218 char c; 219 char *start = dst; 220 int state = 0; 221 222 while ((c = *src++)) { 223 again: 224 switch (unvis(dst, c, &state, 0)) { 225 case UNVIS_VALID: 226 dst++; 227 break; 228 case UNVIS_VALIDPUSH: 229 dst++; 230 goto again; 231 case 0: 232 case UNVIS_NOCHAR: 233 break; 234 default: 235 *dst = '\0'; 236 return (-1); 237 } 238 } 239 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID) 240 dst++; 241 *dst = '\0'; 242 return (dst - start); 243 } 244 245 ssize_t 246 strnunvis(char *dst, const char *src, size_t sz) 247 { 248 char c, p; 249 char *start = dst, *end = dst + sz - 1; 250 int state = 0; 251 252 if (sz > 0) 253 *end = '\0'; 254 while ((c = *src++)) { 255 again: 256 switch (unvis(&p, c, &state, 0)) { 257 case UNVIS_VALID: 258 if (dst < end) 259 *dst = p; 260 dst++; 261 break; 262 case UNVIS_VALIDPUSH: 263 if (dst < end) 264 *dst = p; 265 dst++; 266 goto again; 267 case 0: 268 case UNVIS_NOCHAR: 269 break; 270 default: 271 if (dst <= end) 272 *dst = '\0'; 273 return (-1); 274 } 275 } 276 if (unvis(&p, c, &state, UNVIS_END) == UNVIS_VALID) { 277 if (dst < end) 278 *dst = p; 279 dst++; 280 } 281 if (dst <= end) 282 *dst = '\0'; 283 return (dst - start); 284 } 285 286