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, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include <ctype.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <dlfcn.h>
  26 #include <gnu/lib-names.h>
  27 #include <bits/libc-lock.h>
  28
  29 /* Get specification for idna_to_ascii_lz. */
  30 #include "idna.h"
  31
  32 /* Handle of the libidn  DSO.  */
  33 static void *h;
  34
  35
  36 static int (*to_ascii_lz) (const char *input, char **output, int flags);
  37 static int (*to_unicode_lzlz) (const char *input, char **output, int flags);
  38
  39
  40 static void
  41 load_dso (void)
  42 {
  43   /* Lock protecting the DSO loading.  */
  44   __libc_lock_define_initialized (static, lock);
  45
  46   __libc_lock_lock (lock);
  47
  48   /* Retest in case some other thread arrived here at the same time.  */
  49   if (h == NULL)
  50     {
  51       h = __libc_dlopen (LIBCIDN_SO);
  52
  53       if (h == NULL)
  54         h = (void *) 1l;
  55       else
  56         {
  57           /* Get the function we are interested in.  */
  58           to_ascii_lz = __libc_dlsym (h, "idna_to_ascii_lz");
  59           to_unicode_lzlz = __libc_dlsym (h, "idna_to_unicode_lzlz");
  60           if (to_ascii_lz == NULL || to_unicode_lzlz == NULL)
  61             {
  62               __libc_dlclose (h);
  63               h = (void *) 1l;
  64             }
  65         }
  66     }
  67
  68   __libc_lock_unlock (lock);
  69 }
  70
  71
  72 /* Stub to dlopen libcidn.so and invoke the real idna_to_ascii_lz, or
  73    return IDNA_DLOPEN_ERROR on failure.  */
  74 int
  75 __idna_to_unicode_lzlz (const char *input, char **output, int flags)
  76 {
  77   /* If the input string contains no "xn--" prefix for a component of
  78      the name we can pass it up right away.  */
  79   const char *cp = input;
  80   while (*cp != '\0')
  81     {
  82       if (strncmp (cp, IDNA_ACE_PREFIX, strlen (IDNA_ACE_PREFIX)) == 0)
  83         break;
  84
  85       /* On to the next part of the name.  */
  86       cp = __strchrnul (cp, '.');
  87       if (*cp == '.')
  88         ++cp;
  89     }
  90
  91   if (*cp == '\0')
  92     {
  93       *output = (char *) input;
  94       return IDNA_SUCCESS;
  95     }
  96
  97   if (h == NULL)
  98     load_dso ();
  99
 100   if (h == (void *) 1l)
 101     return IDNA_DLOPEN_ERROR;
 102
 103   return to_unicode_lzlz (input, output, flags);
 104 }
 105
 106
 107 /* Stub to dlopen libcidn.so and invoke the real idna_to_ascii_lz, or
 108    return IDNA_DLOPEN_ERROR on failure.  */
 109 int
 110 __idna_to_ascii_lz (const char *input, char **output, int flags)
 111 {
 112   /* If the input string contains no non-ASCII character the output
 113      string will be the same.  No valid locale encoding does not have
 114      this property.  */
 115   const char *cp = input;
 116   while (*cp != '\0' && isascii (*cp))
 117     ++cp;
 118
 119   if (*cp == '\0')
 120     {
 121       *output = (char *) input;
 122       return IDNA_SUCCESS;
 123     }
 124
 125   if (h == NULL)
 126     load_dso ();
 127
 128   if (h == (void *) 1l)
 129     return IDNA_DLOPEN_ERROR;
 130
 131   return to_ascii_lz (input, output, flags);
 132 }
 133
 134
 135 libc_freeres_fn (unload_libidn)
 136 {
 137   if (h != NULL && h != (void *) 1l)
 138     {
 139       __libc_dlclose (h);
 140       h = (void *) 1l;
 141     }
 142 }