68 lines
2.2 KiB
C
68 lines
2.2 KiB
C
/* areadlinkat.c -- readlinkat wrapper to return malloc'd link name
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Unlike xreadlinkat, only call exit on failure to change directory.
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Copyright (C) 2001, 2003-2007, 2009-2022 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Jim Meyering <jim@meyering.net>,
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and Bruno Haible <bruno@clisp.org>,
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and Eric Blake <ebb9@byu.net>. */
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#include <config.h>
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/* Specification. */
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#include "areadlink.h"
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#include <stdlib.h>
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#include "careadlinkat.h"
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#if HAVE_READLINKAT
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/* Call readlinkat to get the symbolic link value of FILENAME relative to FD.
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Return a pointer to that NUL-terminated string in malloc'd storage.
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If readlinkat fails, return NULL and set errno (although failure to
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change directory will issue a diagnostic and exit).
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If allocation fails, or if the link value is longer than SIZE_MAX :-),
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return NULL and set errno to ENOMEM. */
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char *
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areadlinkat (int fd, char const *filename)
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{
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return careadlinkat (fd, filename, NULL, 0, NULL, readlinkat);
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}
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#else /* !HAVE_READLINKAT */
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/* It is more efficient to change directories only once and call
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areadlink, rather than repeatedly call the replacement
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readlinkat. */
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# define AT_FUNC_NAME areadlinkat
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# define AT_FUNC_F1 areadlink
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# define AT_FUNC_POST_FILE_PARAM_DECLS /* empty */
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# define AT_FUNC_POST_FILE_ARGS /* empty */
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# define AT_FUNC_RESULT char *
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# define AT_FUNC_FAIL NULL
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# include "at-func.c"
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# undef AT_FUNC_NAME
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# undef AT_FUNC_F1
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# undef AT_FUNC_POST_FILE_PARAM_DECLS
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# undef AT_FUNC_POST_FILE_ARGS
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# undef AT_FUNC_RESULT
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# undef AT_FUNC_FAIL
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#endif /* !HAVE_READLINKAT */
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