summaryrefslogtreecommitdiff
path: root/inet/idna.c
blob: c561bf2e9e15ad23c397a29f86771bdc243b9551 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
/* IDNA functions, forwarding to implementations in libidn2.
   Copyright (C) 2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <allocate_once.h>
#include <dlfcn.h>
#include <inet/net-internal.h>
#include <netdb.h>
#include <stdbool.h>

/* Use the soname and version to locate libidn2, to ensure a
   compatible ABI.  */
#define LIBIDN2_SONAME "libidn2.so.0"
#define LIBIDN2_VERSION "IDN2_0.0.0"

/* Return codes from libidn2.  */
enum
  {
    IDN2_OK = 0,
    IDN2_MALLOC = -100,
  };

/* Functions from libidn2.  */
struct functions
{
  void *handle;
  int (*lookup_ul) (const char *src, char **result, int flags);
  int (*to_unicode_lzlz) (const char *name, char **result, int flags);
};

static void *
functions_allocate (void *closure)
{
  struct functions *result = malloc (sizeof (*result));
  if (result == NULL)
    return NULL;

  void *handle = __libc_dlopen (LIBIDN2_SONAME);
  if (handle == NULL)
    /* Do not cache open failures.  The library may appear
       later.  */
    {
      free (result);
      return NULL;
    }

  void *ptr_lookup_ul
    = __libc_dlvsym (handle, "idn2_lookup_ul", LIBIDN2_VERSION);
  void *ptr_to_unicode_lzlz
    = __libc_dlvsym (handle, "idn2_to_unicode_lzlz", LIBIDN2_VERSION);
  if (ptr_lookup_ul == NULL || ptr_to_unicode_lzlz == NULL)
    {
      __libc_dlclose (handle);
      free (result);
      return NULL;
    }

  result->handle = handle;
  result->lookup_ul = ptr_lookup_ul;
  result->to_unicode_lzlz = ptr_to_unicode_lzlz;
#ifdef PTR_MANGLE
  PTR_MANGLE (result->lookup_ul);
  PTR_MANGLE (result->to_unicode_lzlz);
#endif

  return result;
}

static void
functions_deallocate (void *closure, void *ptr)
{
  struct functions *functions = ptr;
  __libc_dlclose (functions->handle);
  free (functions);
}

/* Ensure that *functions is initialized and return the value of the
   pointer.  If the library cannot be loaded, return NULL.  */
static inline struct functions *
get_functions (void)
{
  static void *functions;
  return allocate_once (&functions, functions_allocate, functions_deallocate,
                        NULL);
}

/* strdup with an EAI_* error code.  */
static int
gai_strdup (const char *name, char **result)
{
  char *ptr = __strdup (name);
  if (ptr == NULL)
    return EAI_MEMORY;
  *result = ptr;
  return 0;
}

int
__idna_to_dns_encoding (const char *name, char **result)
{
  switch (__idna_name_classify (name))
    {
    case idna_name_ascii:
      /* Nothing to convert.  */
      return gai_strdup (name, result);
    case idna_name_nonascii:
      /* Encoding needed.  Handled below.  */
      break;
    case idna_name_nonascii_backslash:
    case idna_name_encoding_error:
      return EAI_IDN_ENCODE;
    case idna_name_memory_error:
      return EAI_MEMORY;
    case idna_name_error:
      return EAI_SYSTEM;
    }

  struct functions *functions = get_functions ();
  if (functions == NULL)
    /* We report this as an encoding error (assuming that libidn2 is
       not installed), although the root cause may be a temporary
       error condition due to resource shortage.  */
    return EAI_IDN_ENCODE;
  char *ptr = NULL;
  __typeof__ (functions->lookup_ul) fptr = functions->lookup_ul;
#ifdef PTR_DEMANGLE
  PTR_DEMANGLE (fptr);
#endif
  int ret = fptr (name, &ptr, 0);
  if (ret == 0)
    {
      /* Assume that idn2_free is equivalent to free.  */
      *result = ptr;
      return 0;
    }
  else if (ret == IDN2_MALLOC)
    return EAI_MEMORY;
  else
    return EAI_IDN_ENCODE;
}
libc_hidden_def (__idna_to_dns_encoding)

int
__idna_from_dns_encoding (const char *name, char **result)
{
  struct functions *functions = get_functions ();
  if (functions == NULL)
    /* Simply use the encoded name, assuming that it is not punycode
       (but even a punycode name would be syntactically valid).  */
    return gai_strdup (name, result);
  char *ptr = NULL;
  __typeof__ (functions->to_unicode_lzlz) fptr = functions->to_unicode_lzlz;
#ifdef PTR_DEMANGLE
  PTR_DEMANGLE (fptr);
#endif
  int ret = fptr (name, &ptr, 0);
  if (ret == 0)
    {
      /* Assume that idn2_free is equivalent to free.  */
      *result = ptr;
      return 0;
    }
  else if (ret == IDN2_MALLOC)
    return EAI_MEMORY;
  else
    return EAI_IDN_ENCODE;
}
libc_hidden_def (__idna_from_dns_encoding)