1 /* Test for access to file, relative to open directory. Linux version.
2 Copyright (C) 2006-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
25 #include <sys/types.h>
31 faccessat (int fd
, const char *file
, int mode
, int flag
)
33 if (flag
& ~(AT_SYMLINK_NOFOLLOW
| AT_EACCESS
))
34 return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL
);
36 if ((flag
== 0 || ((flag
& ~AT_EACCESS
) == 0 && ! __libc_enable_secure
)))
37 return INLINE_SYSCALL (faccessat
, 3, fd
, file
, mode
);
40 if (__fxstatat64 (_STAT_VER
, fd
, file
, &stats
, flag
& AT_SYMLINK_NOFOLLOW
))
43 mode
&= (X_OK
| W_OK
| R_OK
); /* Clear any bogus bits. */
44 #if R_OK != S_IROTH || W_OK != S_IWOTH || X_OK != S_IXOTH
45 # error Oops, portability assumptions incorrect.
49 return 0; /* The file exists. */
51 uid_t uid
= (flag
& AT_EACCESS
) ? __geteuid () : __getuid ();
53 /* The super-user can read and write any file, and execute any file
54 that anyone can execute. */
55 if (uid
== 0 && ((mode
& X_OK
) == 0
56 || (stats
.st_mode
& (S_IXUSR
| S_IXGRP
| S_IXOTH
))))
59 int granted
= (uid
== stats
.st_uid
60 ? (unsigned int) (stats
.st_mode
& (mode
<< 6)) >> 6
61 : (stats
.st_gid
== ((flag
& AT_EACCESS
)
62 ? __getegid () : __getgid ())
63 || __group_member (stats
.st_gid
))
64 ? (unsigned int) (stats
.st_mode
& (mode
<< 3)) >> 3
65 : (stats
.st_mode
& mode
));
70 return INLINE_SYSCALL_ERROR_RETURN_VALUE (EACCES
);