libidn/idn-stub.c

   1 /* idn-stub.c --- Stub to dlopen libcidn.so and invoke idna_to_ascii_lz.
   2  * Copyright (C) 2003, 2004  Simon Josefsson
   3  *
   4  * This file is part of GNU Libidn.
   5  *
   6  * GNU Libidn is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * GNU Libidn is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with GNU Libidn; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <ctype.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <dlfcn.h>
  24 #include <gnu/lib-names.h>
  25 #include <bits/libc-lock.h>
  26
  27 /* Get specification for idna_to_ascii_lz. */
  28 #include "idna.h"
  29
  30 /* Handle of the libidn  DSO.  */
  31 static void *h;
  32
  33
  34 static int (*to_ascii_lz) (const char *input, char **output, int flags);
  35 static int (*to_unicode_lzlz) (const char *input, char **output, int flags);
  36
  37
  38 static void
  39 load_dso (void)
  40 {
  41   /* Lock protecting the DSO loading.  */
  42   __libc_lock_define_initialized (static, lock);
  43
  44   __libc_lock_lock (lock);
  45
  46   /* Retest in case some other thread arrived here at the same time.  */
  47   if (h == NULL)
  48     {
  49       h = __libc_dlopen (LIBCIDN_SO);
  50
  51       if (h == NULL)
  52         h = (void *) 1l;
  53       else
  54         {
  55           /* Get the function we are interested in.  */
  56           to_ascii_lz = __libc_dlsym (h, "idna_to_ascii_lz");
  57           to_unicode_lzlz = __libc_dlsym (h, "idna_to_unicode_lzlz");
  58           if (to_ascii_lz == NULL || to_unicode_lzlz == NULL)
  59             {
  60               __libc_dlclose (h);
  61               h = (void *) 1l;
  62             }
  63         }
  64     }
  65
  66   __libc_lock_unlock (lock);
  67 }
  68
  69
  70 /* Stub to dlopen libcidn.so and invoke the real idna_to_ascii_lz, or
  71    return IDNA_DLOPEN_ERROR on failure.  */
  72 int
  73 __idna_to_unicode_lzlz (const char *input, char **output, int flags)
  74 {
  75   /* If the input string contains no "xn--" prefix for a component of
  76      the name we can pass it up right away.  */
  77   const char *cp = input;
  78   while (*cp != '\0')
  79     {
  80       if (strncmp (cp, IDNA_ACE_PREFIX, strlen (IDNA_ACE_PREFIX)) == 0)
  81         break;
  82
  83       /* On to the next part of the name.  */
  84       cp = __strchrnul (cp, '.');
  85       if (*cp == '.')
  86         ++cp;
  87     }
  88
  89   if (*cp == '\0')
  90     {
  91       *output = (char *) input;
  92       return IDNA_SUCCESS;
  93     }
  94
  95   if (h == NULL)
  96     load_dso ();
  97
  98   if (h == (void *) 1l)
  99     return IDNA_DLOPEN_ERROR;
 100
 101   return to_unicode_lzlz (input, output, flags);
 102 }
 103
 104
 105 /* Stub to dlopen libcidn.so and invoke the real idna_to_ascii_lz, or
 106    return IDNA_DLOPEN_ERROR on failure.  */
 107 int
 108 __idna_to_ascii_lz (const char *input, char **output, int flags)
 109 {
 110   /* If the input string contains no non-ASCII character the output
 111      string will be the same.  No valid locale encoding does not have
 112      this property.  */
 113   const char *cp = input;
 114   while (*cp != '\0' && isascii (*cp))
 115     ++cp;
 116
 117   if (*cp == '\0')
 118     {
 119       *output = (char *) input;
 120       return IDNA_SUCCESS;
 121     }
 122
 123   if (h == NULL)
 124     load_dso ();
 125
 126   if (h == (void *) 1l)
 127     return IDNA_DLOPEN_ERROR;
 128
 129   return to_ascii_lz (input, output, flags);
 130 }
 131
 132
 133 #if IS_IN (libc)
 134 libc_freeres_fn (unload_libidn)
 135 {
 136   if (h != NULL && h != (void *) 1l)
 137     {
 138       __libc_dlclose (h);
 139       h = (void *) 1l;
 140     }
 141 }
 142 #endif