lib/qmark.c

   1 /* qmark.c -- quote 'dangerous' filenames
   2
   3    Copyright (C) 2005 Free Software Foundation, Inc.
   4    Derived from courutils' ls.c:
   5    Copyright (C) 85, 88, 90, 91, 1995-2005 Free Software Foundation, Inc.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include <config.h>
  22
  23 # include <stddef.h>
  24 # include <stdlib.h>
  25 #include <ctype.h>
  26
  27 #if HAVE_STRING_H || STDC_HEADERS
  28 #include <string.h>
  29 #else
  30 #include <strings.h>
  31 #endif
  32
  33
  34 /* Get mbstate_t, mbrtowc(), mbsinit(), wcwidth().  */
  35 #if HAVE_WCHAR_H
  36 # include <wchar.h>
  37 #endif
  38
  39 #include "printquoted.h"
  40
  41
  42 /*
  43    This comment, IN_CTYPE_DOMAIN and ISPRINT were borrowed from
  44    coreutils at Sun Jun  5 21:17:40 2005 UTC.
  45
  46    Jim Meyering writes:
  47
  48    "... Some ctype macros are valid only for character codes that
  49    isascii says are ASCII (SGI's IRIX-4.0.5 is one such system --when
  50    using /bin/cc or gcc but without giving an ansi option).  So, all
  51    ctype uses should be through macros like ISPRINT...  If
  52    STDC_HEADERS is defined, then autoconf has verified that the ctype
  53    macros don't need to be guarded with references to isascii. ...
  54    Defining isascii to 1 should let any compiler worth its salt
  55    eliminate the && through constant folding."
  56
  57    Bruno Haible adds:
  58
  59    "... Furthermore, isupper(c) etc. have an undefined result if c is
  60    outside the range -1 <= c <= 255. One is tempted to write isupper(c)
  61    with c being of type `char', but this is wrong if c is an 8-bit
  62    character >= 128 which gets sign-extended to a negative value.
  63    The macro ISUPPER protects against this as well."  */
  64
  65
  66
  67
  68 /* ISPRINT is defined in <sys/euc.h> on at least Solaris2.6 systems.  */
  69 #undef ISPRINT
  70 #define ISPRINT(c) (IN_CTYPE_DOMAIN (c) && isprint (c))
  71
  72 #if STDC_HEADERS || (!defined (isascii) && !HAVE_ISASCII)
  73 # define IN_CTYPE_DOMAIN(c) 1
  74 #else
  75 # define IN_CTYPE_DOMAIN(c) isascii(c)
  76 #endif
  77
  78
  79
  80
  81
  82 /* Convert a possibly-signed character to an unsigned character.  This is
  83  * a bit safer than casting to unsigned char, since it catches some type
  84  * errors that the cast doesn't.
  85  *
  86  * This code taken from coreutils' system.h header at
  87  * Sun Jun  5 21:05:21 2005 UTC.
  88  */
  89 static inline unsigned char to_uchar (char ch)
  90 {
  91   return ch;
  92 }
  93
  94
  95
  96 static size_t
  97 unibyte_qmark_chars(char *buf, size_t len)
  98 {
  99   char *p = buf;
 100   char const *plimit = buf + len;
 101
 102   while (p < plimit)
 103     {
 104       if (! ISPRINT (to_uchar (*p)))
 105         *p = '?';
 106       p++;
 107     }
 108   return len;
 109 }
 110
 111
 112 #if HAVE_MBRTOWC
 113 static size_t
 114 multibyte_qmark_chars(char *buf, size_t len)
 115 {
 116   if (MB_CUR_MAX <= 1)
 117     {
 118       return unibyte_qmark_chars(buf, len);
 119     }
 120   else
 121     {
 122       char const *p = buf;
 123       char const *plimit = buf + len;
 124       char *q = buf;
 125
 126       while (p < plimit)
 127         switch (*p)
 128           {
 129           case ' ': case '!': case '"': case '#': case '%':
 130           case '&': case '\'': case '(': case ')': case '*':
 131           case '+': case ',': case '-': case '.': case '/':
 132           case '0': case '1': case '2': case '3': case '4':
 133           case '5': case '6': case '7': case '8': case '9':
 134           case ':': case ';': case '<': case '=': case '>':
 135           case '?':
 136           case 'A': case 'B': case 'C': case 'D': case 'E':
 137           case 'F': case 'G': case 'H': case 'I': case 'J':
 138           case 'K': case 'L': case 'M': case 'N': case 'O':
 139           case 'P': case 'Q': case 'R': case 'S': case 'T':
 140           case 'U': case 'V': case 'W': case 'X': case 'Y':
 141           case 'Z':
 142           case '[': case '\\': case ']': case '^': case '_':
 143           case 'a': case 'b': case 'c': case 'd': case 'e':
 144           case 'f': case 'g': case 'h': case 'i': case 'j':
 145           case 'k': case 'l': case 'm': case 'n': case 'o':
 146           case 'p': case 'q': case 'r': case 's': case 't':
 147           case 'u': case 'v': case 'w': case 'x': case 'y':
 148           case 'z': case '{': case '|': case '}': case '~':
 149             /* These characters are printable ASCII characters.  */
 150             *q++ = *p++;
 151             break;
 152           default:
 153             /* If we have a multibyte sequence, copy it until we
 154                reach its end, replacing each non-printable multibyte
 155                character with a single question mark.  */
 156             {
 157               mbstate_t mbstate;
 158               memset (&mbstate, 0, sizeof mbstate);
 159               do
 160                 {
 161                   wchar_t wc;
 162                   size_t bytes;
 163                   int w;
 164
 165                   bytes = mbrtowc (&wc, p, plimit - p, &mbstate);
 166
 167                   if (bytes == (size_t) -1)
 168                     {
 169                       /* An invalid multibyte sequence was
 170                          encountered.  Skip one input byte, and
 171                          put a question mark.  */
 172                       p++;
 173                       *q++ = '?';
 174                       break;
 175                     }
 176
 177                   if (bytes == (size_t) -2)
 178                     {
 179                       /* An incomplete multibyte character
 180                          at the end.  Replace it entirely with
 181                          a question mark.  */
 182                       p = plimit;
 183                       *q++ = '?';
 184                       break;
 185                     }
 186
 187                   if (bytes == 0)
 188                     /* A null wide character was encountered.  */
 189                     bytes = 1;
 190
 191                   w = wcwidth (wc);
 192                   if (w >= 0)
 193                     {
 194                       /* A printable multibyte character.
 195                          Keep it.  */
 196                       for (; bytes > 0; --bytes)
 197                         *q++ = *p++;
 198                     }
 199                   else
 200                     {
 201                       /* An unprintable multibyte character.
 202                          Replace it entirely with a question
 203                          mark.  */
 204                       p += bytes;
 205                       *q++ = '?';
 206                     }
 207                 }
 208               while (! mbsinit (&mbstate));
 209             }
 210             break;
 211           }
 212
 213       /* The buffer may have shrunk.  */
 214       len = q - buf;
 215       return len;
 216     }
 217 }
 218 #endif
 219
 220
 221 /* Scan BUF, replacing any dangerous-looking characters with question
 222  * marks.  This code is taken from the ls.c file in coreutils as at
 223  * Sun Jun  5 20:51:54 2005 UTC.
 224  *
 225  * This function may shrink the buffer.   Either way, the new length
 226  * is returned.
 227  */
 228 size_t
 229 qmark_chars(char *buf, size_t len)
 230 {
 231 #if HAVE_MBRTOWC
 232   return multibyte_qmark_chars(buf, len);
 233 #else
 234   return unibyte_qmark_chars(buf, len);
 235 #endif
 236 }
 237