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d4697bc9 | 1 | /* Copyright (C) 2005-2014 Free Software Foundation, Inc. |
5c46041a UD |
2 | This file is part of the GNU C Library. |
3 | ||
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. | |
8 | ||
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. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
5c46041a UD |
17 | |
18 | #include <errno.h> | |
19 | #include <fcntl.h> | |
20 | #include <stddef.h> | |
21 | #include <stdio.h> | |
22 | #include <stdlib.h> | |
23 | #include <string.h> | |
24 | #include <sysdep.h> | |
25 | #include <unistd.h> | |
7c65e900 | 26 | #include <kernel-features.h> |
5c46041a UD |
27 | |
28 | ||
29 | /* Make a symbolic link to FROM named TO relative to TOFD. */ | |
30 | int | |
31 | symlinkat (from, tofd, to) | |
32 | const char *from; | |
33 | int tofd; | |
34 | const char *to; | |
35 | { | |
7c65e900 UD |
36 | int result; |
37 | ||
38 | #ifdef __NR_symlinkat | |
39 | # ifndef __ASSUME_ATFCTS | |
40 | if (__have_atfcts >= 0) | |
41 | # endif | |
42 | { | |
43 | result = INLINE_SYSCALL (symlinkat, 3, from, tofd, to); | |
44 | # ifndef __ASSUME_ATFCTS | |
45 | if (result == -1 && errno == ENOSYS) | |
46 | __have_atfcts = -1; | |
47 | else | |
48 | # endif | |
49 | return result; | |
50 | } | |
51 | #endif | |
52 | ||
53 | #ifndef __ASSUME_ATFCTS | |
5c46041a UD |
54 | char *buf = NULL; |
55 | ||
56 | if (tofd != AT_FDCWD && to[0] != '/') | |
57 | { | |
58 | size_t tolen = strlen (to); | |
a1ffb40e | 59 | if (__glibc_unlikely (tolen == 0)) |
801720e6 UD |
60 | { |
61 | __set_errno (ENOENT); | |
62 | return -1; | |
63 | } | |
64 | ||
5c46041a UD |
65 | static const char procfd[] = "/proc/self/fd/%d/%s"; |
66 | /* Buffer for the path name we are going to use. It consists of | |
67 | - the string /proc/self/fd/ | |
68 | - the file descriptor number | |
69 | - the file name provided. | |
70 | The final NUL is included in the sizeof. A bit of overhead | |
71 | due to the format elements compensates for possible negative | |
72 | numbers. */ | |
73 | size_t buflen = sizeof (procfd) + sizeof (int) * 3 + tolen; | |
74 | buf = __alloca (buflen); | |
75 | ||
76 | __snprintf (buf, buflen, procfd, tofd, to); | |
77 | to = buf; | |
78 | } | |
79 | ||
80 | INTERNAL_SYSCALL_DECL (err); | |
81 | ||
7c65e900 | 82 | result = INTERNAL_SYSCALL (symlink, err, 2, from, to); |
5c46041a | 83 | |
a1ffb40e | 84 | if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err))) |
5c46041a UD |
85 | { |
86 | __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), tofd, buf); | |
87 | result = -1; | |
88 | } | |
89 | ||
90 | return result; | |
7c65e900 | 91 | #endif |
5c46041a | 92 | } |