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 2, or (at your option)
  10    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, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  20    USA.
  21 */
  22
  23 #include <config.h>
  24
  25 # include <stddef.h>
  26 # include <stdlib.h>
  27 #include <ctype.h>
  28
  29 #if HAVE_STRING_H || STDC_HEADERS
  30 #include <string.h>
  31 #else
  32 #include <strings.h>
  33 #endif
  34
  35
  36 /* Get mbstate_t, mbrtowc(), mbsinit(), wcwidth().  */
  37 #if HAVE_WCHAR_H
  38 # include <wchar.h>
  39 #endif
  40
  41 #include "printquoted.h"
  42
  43
  44 /*
  45    This comment, IN_CTYPE_DOMAIN and ISPRINT were borrowed from
  46    coreutils at Sun Jun  5 21:17:40 2005 UTC.
  47
  48    Jim Meyering writes:
  49
  50    "... Some ctype macros are valid only for character codes that
  51    isascii says are ASCII (SGI's IRIX-4.0.5 is one such system --when
  52    using /bin/cc or gcc but without giving an ansi option).  So, all
  53    ctype uses should be through macros like ISPRINT...  If
  54    STDC_HEADERS is defined, then autoconf has verified that the ctype
  55    macros don't need to be guarded with references to isascii. ...
  56    Defining isascii to 1 should let any compiler worth its salt
  57    eliminate the && through constant folding."
  58
  59    Bruno Haible adds:
  60
  61    "... Furthermore, isupper(c) etc. have an undefined result if c is
  62    outside the range -1 <= c <= 255. One is tempted to write isupper(c)
  63    with c being of type `char', but this is wrong if c is an 8-bit
  64    character >= 128 which gets sign-extended to a negative value.
  65    The macro ISUPPER protects against this as well."  */
  66
  67
  68
  69
  70 /* ISPRINT is defined in <sys/euc.h> on at least Solaris2.6 systems.  */
  71 #undef ISPRINT
  72 #define ISPRINT(c) (IN_CTYPE_DOMAIN (c) && isprint (c))
  73
  74 #if STDC_HEADERS || (!defined (isascii) && !HAVE_ISASCII)
  75 # define IN_CTYPE_DOMAIN(c) 1
  76 #else
  77 # define IN_CTYPE_DOMAIN(c) isascii(c)
  78 #endif
  79
  80
  81
  82
  83
  84 /* Convert a possibly-signed character to an unsigned character.  This is
  85  * a bit safer than casting to unsigned char, since it catches some type
  86  * errors that the cast doesn't.
  87  *
  88  * This code taken from coreutils' system.h header at
  89  * Sun Jun  5 21:05:21 2005 UTC.
  90  */
  91 static inline unsigned char to_uchar (char ch)
  92 {
  93   return ch;
  94 }
  95
  96
  97
  98 static size_t
  99 unibyte_qmark_chars(char *buf, size_t len)
 100 {
 101   char *p = buf;
 102   char const *plimit = buf + len;
 103
 104   while (p < plimit)
 105     {
 106       if (! ISPRINT (to_uchar (*p)))
 107         *p = '?';
 108       p++;
 109     }
 110   return len;
 111 }
 112
 113
 114 #if HAVE_MBRTOWC
 115 static size_t
 116 multibyte_qmark_chars(char *buf, size_t len)
 117 {
 118   if (MB_CUR_MAX <= 1)
 119     {
 120       return unibyte_qmark_chars(buf, len);
 121     }
 122   else
 123     {
 124       char const *p = buf;
 125       char const *plimit = buf + len;
 126       char *q = buf;
 127
 128       while (p < plimit)
 129         switch (*p)
 130           {
 131           case ' ': case '!': case '"': case '#': case '%':
 132           case '&': case '\'': case '(': case ')': case '*':
 133           case '+': case ',': case '-': case '.': case '/':
 134           case '0': case '1': case '2': case '3': case '4':
 135           case '5': case '6': case '7': case '8': case '9':
 136           case ':': case ';': case '<': case '=': case '>':
 137           case '?':
 138           case 'A': case 'B': case 'C': case 'D': case 'E':
 139           case 'F': case 'G': case 'H': case 'I': case 'J':
 140           case 'K': case 'L': case 'M': case 'N': case 'O':
 141           case 'P': case 'Q': case 'R': case 'S': case 'T':
 142           case 'U': case 'V': case 'W': case 'X': case 'Y':
 143           case 'Z':
 144           case '[': case '\\': case ']': case '^': case '_':
 145           case 'a': case 'b': case 'c': case 'd': case 'e':
 146           case 'f': case 'g': case 'h': case 'i': case 'j':
 147           case 'k': case 'l': case 'm': case 'n': case 'o':
 148           case 'p': case 'q': case 'r': case 's': case 't':
 149           case 'u': case 'v': case 'w': case 'x': case 'y':
 150           case 'z': case '{': case '|': case '}': case '~':
 151             /* These characters are printable ASCII characters.  */
 152             *q++ = *p++;
 153             break;
 154           default:
 155             /* If we have a multibyte sequence, copy it until we
 156                reach its end, replacing each non-printable multibyte
 157                character with a single question mark.  */
 158             {
 159               mbstate_t mbstate;
 160               memset (&mbstate, 0, sizeof mbstate);
 161               do
 162                 {
 163                   wchar_t wc;
 164                   size_t bytes;
 165                   int w;
 166
 167                   bytes = mbrtowc (&wc, p, plimit - p, &mbstate);
 168
 169                   if (bytes == (size_t) -1)
 170                     {
 171                       /* An invalid multibyte sequence was
 172                          encountered.  Skip one input byte, and
 173                          put a question mark.  */
 174                       p++;
 175                       *q++ = '?';
 176                       break;
 177                     }
 178
 179                   if (bytes == (size_t) -2)
 180                     {
 181                       /* An incomplete multibyte character
 182                          at the end.  Replace it entirely with
 183                          a question mark.  */
 184                       p = plimit;
 185                       *q++ = '?';
 186                       break;
 187                     }
 188
 189                   if (bytes == 0)
 190                     /* A null wide character was encountered.  */
 191                     bytes = 1;
 192
 193                   w = wcwidth (wc);
 194                   if (w >= 0)
 195                     {
 196                       /* A printable multibyte character.
 197                          Keep it.  */
 198                       for (; bytes > 0; --bytes)
 199                         *q++ = *p++;
 200                     }
 201                   else
 202                     {
 203                       /* An unprintable multibyte character.
 204                          Replace it entirely with a question
 205                          mark.  */
 206                       p += bytes;
 207                       *q++ = '?';
 208                     }
 209                 }
 210               while (! mbsinit (&mbstate));
 211             }
 212             break;
 213           }
 214
 215       /* The buffer may have shrunk.  */
 216       len = q - buf;
 217       return len;
 218     }
 219 }
 220 #endif
 221
 222
 223 /* Scan BUF, replacing any dangerous-looking characters with question
 224  * marks.  This code is taken from the ls.c file in coreutils as at
 225  * Sun Jun  5 20:51:54 2005 UTC.
 226  *
 227  * This function may shrink the buffer.   Either way, the new length
 228  * is returned.
 229  */
 230 size_t
 231 qmark_chars(char *buf, size_t len)
 232 {
 233 #if HAVE_MBRTOWC
 234   return multibyte_qmark_chars(buf, len);
 235 #else
 236   return unibyte_qmark_chars(buf, len);
 237 #endif
 238 }
 239