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/* IDNA functions, forwarding to implementations in libidn2.
Copyright (C) 2018-2024 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
<https://www.gnu.org/licenses/>. */
#include <allocate_once.h>
#include <dlfcn.h>
#include <inet/net-internal.h>
#include <netdb.h>
#include <stdbool.h>
#include <pointer_guard.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;
PTR_MANGLE (result->lookup_ul);
PTR_MANGLE (result->to_unicode_lzlz);
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;
PTR_DEMANGLE (fptr);
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;
PTR_DEMANGLE (fptr);
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)
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