compat/vis.c

   1 /*      $OpenBSD: vis.c,v 1.24 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 <errno.h>
  33 #include <ctype.h>
  34 #include <limits.h>
  35 #include <string.h>
  36 #include <stdlib.h>
  37
  38 #include "compat.h"
  39
  40 #define isoctal(c)      (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
  41 #define isvisible(c,flag)                                               \
  42         (((c) == '\\' || (flag & VIS_ALL) == 0) &&                      \
  43         (((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&            \
  44         (((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||      \
  45                 (flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||     \
  46         ((flag & VIS_SP) == 0 && (c) == ' ') ||                         \
  47         ((flag & VIS_TAB) == 0 && (c) == '\t') ||                       \
  48         ((flag & VIS_NL) == 0 && (c) == '\n') ||                        \
  49         ((flag & VIS_SAFE) && ((c) == '\b' ||                           \
  50                 (c) == '\007' || (c) == '\r' ||                         \
  51                 isgraph((u_char)(c))))))
  52
  53 /*
  54  * vis - visually encode characters
  55  */
  56 char *
  57 vis(char *dst, int c, int flag, int nextc)
  58 {
  59         if (isvisible(c, flag)) {
  60                 if ((c == '"' && (flag & VIS_DQ) != 0) ||
  61                     (c == '\\' && (flag & VIS_NOSLASH) == 0))
  62                         *dst++ = '\\';
  63                 *dst++ = c;
  64                 *dst = '\0';
  65                 return (dst);
  66         }
  67
  68         if (flag & VIS_CSTYLE) {
  69                 switch(c) {
  70                 case '\n':
  71                         *dst++ = '\\';
  72                         *dst++ = 'n';
  73                         goto done;
  74                 case '\r':
  75                         *dst++ = '\\';
  76                         *dst++ = 'r';
  77                         goto done;
  78                 case '\b':
  79                         *dst++ = '\\';
  80                         *dst++ = 'b';
  81                         goto done;
  82                 case '\a':
  83                         *dst++ = '\\';
  84                         *dst++ = 'a';
  85                         goto done;
  86                 case '\v':
  87                         *dst++ = '\\';
  88                         *dst++ = 'v';
  89                         goto done;
  90                 case '\t':
  91                         *dst++ = '\\';
  92                         *dst++ = 't';
  93                         goto done;
  94                 case '\f':
  95                         *dst++ = '\\';
  96                         *dst++ = 'f';
  97                         goto done;
  98                 case ' ':
  99                         *dst++ = '\\';
 100                         *dst++ = 's';
 101                         goto done;
 102                 case '\0':
 103                         *dst++ = '\\';
 104                         *dst++ = '0';
 105                         if (isoctal(nextc)) {
 106                                 *dst++ = '0';
 107                                 *dst++ = '0';
 108                         }
 109                         goto done;
 110                 }
 111         }
 112         if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
 113             ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
 114                 *dst++ = '\\';
 115                 *dst++ = ((u_char)c >> 6 & 07) + '0';
 116                 *dst++ = ((u_char)c >> 3 & 07) + '0';
 117                 *dst++ = ((u_char)c & 07) + '0';
 118                 goto done;
 119         }
 120         if ((flag & VIS_NOSLASH) == 0)
 121                 *dst++ = '\\';
 122         if (c & 0200) {
 123                 c &= 0177;
 124                 *dst++ = 'M';
 125         }
 126         if (iscntrl((u_char)c)) {
 127                 *dst++ = '^';
 128                 if (c == 0177)
 129                         *dst++ = '?';
 130                 else
 131                         *dst++ = c + '@';
 132         } else {
 133                 *dst++ = '-';
 134                 *dst++ = c;
 135         }
 136 done:
 137         *dst = '\0';
 138         return (dst);
 139 }
 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
 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
 166 int
 167 strnvis(char *dst, const char *src, size_t siz, int flag)
 168 {
 169         char *start, *end;
 170         char tbuf[5];
 171         int c, i;
 172
 173         i = 0;
 174         for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
 175                 if (isvisible(c, flag)) {
 176                         if ((c == '"' && (flag & VIS_DQ) != 0) ||
 177                             (c == '\\' && (flag & VIS_NOSLASH) == 0)) {
 178                                 /* need space for the extra '\\' */
 179                                 if (dst + 1 >= end) {
 180                                         i = 2;
 181                                         break;
 182                                 }
 183                                 *dst++ = '\\';
 184                         }
 185                         i = 1;
 186                         *dst++ = c;
 187                         src++;
 188                 } else {
 189                         i = vis(tbuf, c, flag, *++src) - tbuf;
 190                         if (dst + i <= end) {
 191                                 memcpy(dst, tbuf, i);
 192                                 dst += i;
 193                         } else {
 194                                 src--;
 195                                 break;
 196                         }
 197                 }
 198         }
 199         if (siz > 0)
 200                 *dst = '\0';
 201         if (dst + i > end) {
 202                 /* adjust return value for truncation */
 203                 while ((c = *src))
 204                         dst += vis(tbuf, c, flag, *++src) - tbuf;
 205         }
 206         return (dst - start);
 207 }
 208
 209 int
 210 stravis(char **outp, const char *src, int flag)
 211 {
 212         char *buf;
 213         int len, serrno;
 214
 215         buf = calloc(4, strlen(src) + 1);
 216         if (buf == NULL)
 217                 return -1;
 218         len = strvis(buf, src, flag);
 219         serrno = errno;
 220         *outp = realloc(buf, len + 1);
 221         if (*outp == NULL) {
 222                 *outp = buf;
 223                 errno = serrno;
 224         }
 225         return (len);
 226 }
 227
 228 int
 229 strvisx(char *dst, const char *src, size_t len, int flag)
 230 {
 231         char c;
 232         char *start;
 233
 234         for (start = dst; len > 1; len--) {
 235                 c = *src;
 236                 dst = vis(dst, c, flag, *++src);
 237         }
 238         if (len)
 239                 dst = vis(dst, *src, flag, '\0');
 240         *dst = '\0';
 241         return (dst - start);
 242 }