1 /* Copyright (C) 2005-2013 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
24 #include <kernel-features.h>
27 /* Make a link to FROM named TO but relative paths in TO and FROM are
28 interpreted relative to FROMFD and TOFD respectively. */
30 linkat (fromfd
, from
, tofd
, to
, flags
)
40 # ifndef __ASSUME_ATFCTS
41 if (__have_atfcts
>= 0)
44 result
= INLINE_SYSCALL (linkat
, 5, fromfd
, from
, tofd
, to
, flags
);
45 # ifndef __ASSUME_ATFCTS
46 if (result
== -1 && errno
== ENOSYS
)
54 #ifndef __ASSUME_ATFCTS
55 /* Without kernel support we cannot handle AT_SYMLINK_FOLLOW. */
62 static const char procfd
[] = "/proc/self/fd/%d/%s";
65 if (fromfd
!= AT_FDCWD
&& from
[0] != '/')
67 size_t filelen
= strlen (from
);
68 if (__builtin_expect (filelen
== 0, 0))
74 /* Buffer for the path name we are going to use. It consists of
75 - the string /proc/self/fd/
76 - the file descriptor number
77 - the file name provided.
78 The final NUL is included in the sizeof. A bit of overhead
79 due to the format elements compensates for possible negative
81 size_t buflen
= sizeof (procfd
) + sizeof (int) * 3 + filelen
;
82 buffrom
= alloca (buflen
);
84 __snprintf (buffrom
, buflen
, procfd
, fromfd
, from
);
90 if (tofd
!= AT_FDCWD
&& to
[0] != '/')
92 size_t filelen
= strlen (to
);
93 /* Buffer for the path name we are going to use. It consists of
94 - the string /proc/self/fd/
95 - the file descriptor number
96 - the file name provided.
97 The final NUL is included in the sizeof. A bit of overhead
98 due to the format elements compensates for possible negative
100 size_t buflen
= sizeof (procfd
) + sizeof (int) * 3 + filelen
;
101 bufto
= alloca (buflen
);
103 __snprintf (bufto
, buflen
, procfd
, tofd
, to
);
107 INTERNAL_SYSCALL_DECL (err
);
109 result
= INTERNAL_SYSCALL (link
, err
, 2, from
, to
);
111 if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result
, err
), 0))
113 __atfct_seterrno_2 (INTERNAL_SYSCALL_ERRNO (result
, err
), tofd
, bufto
,