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/* areadlinkat.c -- readlinkat wrapper to return malloc'd link name
Unlike xreadlinkat, only call exit on failure to change directory.
Copyright (C) 2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Jim Meyering <jim@meyering.net>,
and Bruno Haible <bruno@clisp.org>,
and Eric Blake <ebb9@byu.net>. */
#include <config.h>
/* Specification. */
#include "areadlink.h"
#include <stdlib.h>
#include "careadlinkat.h"
#if HAVE_READLINKAT
/* Call readlinkat to get the symbolic link value of FILENAME relative to FD.
Return a pointer to that NUL-terminated string in malloc'd storage.
If readlinkat fails, return NULL and set errno (although failure to
change directory will issue a diagnostic and exit).
If allocation fails, or if the link value is longer than SIZE_MAX :-),
return NULL and set errno to ENOMEM. */
char *
areadlinkat (int fd, char const *filename)
{
return careadlinkat (fd, filename, NULL, 0, NULL, readlinkat);
}
#else /* !HAVE_READLINKAT */
/* It is more efficient to change directories only once and call
areadlink, rather than repeatedly call the replacement
readlinkat. */
# define AT_FUNC_NAME areadlinkat
# define AT_FUNC_F1 areadlink
# define AT_FUNC_POST_FILE_PARAM_DECLS /* empty */
# define AT_FUNC_POST_FILE_ARGS /* empty */
# define AT_FUNC_RESULT char *
# define AT_FUNC_FAIL NULL
# include "at-func.c"
# undef AT_FUNC_NAME
# undef AT_FUNC_F1
# undef AT_FUNC_POST_FILE_PARAM_DECLS
# undef AT_FUNC_POST_FILE_ARGS
# undef AT_FUNC_RESULT
# undef AT_FUNC_FAIL
#endif /* !HAVE_READLINKAT */
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