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93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
/* Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sysdep.h>
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#include <unistd.h>
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#include <kernel-features.h>
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/* Make a symbolic link to FROM named TO relative to TOFD. */
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int
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symlinkat (from, tofd, to)
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const char *from;
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int tofd;
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const char *to;
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{
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int result;
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#ifdef __NR_symlinkat
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# ifndef __ASSUME_ATFCTS
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if (__have_atfcts >= 0)
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# endif
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{
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result = INLINE_SYSCALL (symlinkat, 3, from, tofd, to);
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# ifndef __ASSUME_ATFCTS
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if (result == -1 && errno == ENOSYS)
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__have_atfcts = -1;
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else
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# endif
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return result;
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}
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#endif
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#ifndef __ASSUME_ATFCTS
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char *buf = NULL;
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if (tofd != AT_FDCWD && to[0] != '/')
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{
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size_t tolen = strlen (to);
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if (__builtin_expect (tolen == 0, 0))
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{
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__set_errno (ENOENT);
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return -1;
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}
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static const char procfd[] = "/proc/self/fd/%d/%s";
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/* Buffer for the path name we are going to use. It consists of
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- the string /proc/self/fd/
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- the file descriptor number
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- the file name provided.
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The final NUL is included in the sizeof. A bit of overhead
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due to the format elements compensates for possible negative
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numbers. */
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size_t buflen = sizeof (procfd) + sizeof (int) * 3 + tolen;
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buf = __alloca (buflen);
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__snprintf (buf, buflen, procfd, tofd, to);
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to = buf;
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}
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INTERNAL_SYSCALL_DECL (err);
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result = INTERNAL_SYSCALL (symlink, err, 2, from, to);
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if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 0))
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{
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__atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), tofd, buf);
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result = -1;
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}
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return result;
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#endif
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}
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