mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 01:00:07 +00:00
72 lines
2.3 KiB
C
72 lines
2.3 KiB
C
/* Test for access to file, relative to open directory. Linux version.
|
|
Copyright (C) 2006-2017 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stddef.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <sys/types.h>
|
|
#include <alloca.h>
|
|
#include <sysdep.h>
|
|
|
|
|
|
int
|
|
faccessat (int fd, const char *file, int mode, int flag)
|
|
{
|
|
if (flag & ~(AT_SYMLINK_NOFOLLOW | AT_EACCESS))
|
|
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
|
|
|
|
if ((flag == 0 || ((flag & ~AT_EACCESS) == 0 && ! __libc_enable_secure)))
|
|
return INLINE_SYSCALL (faccessat, 3, fd, file, mode);
|
|
|
|
struct stat64 stats;
|
|
if (__fxstatat64 (_STAT_VER, fd, file, &stats, flag & AT_SYMLINK_NOFOLLOW))
|
|
return -1;
|
|
|
|
mode &= (X_OK | W_OK | R_OK); /* Clear any bogus bits. */
|
|
#if R_OK != S_IROTH || W_OK != S_IWOTH || X_OK != S_IXOTH
|
|
# error Oops, portability assumptions incorrect.
|
|
#endif
|
|
|
|
if (mode == F_OK)
|
|
return 0; /* The file exists. */
|
|
|
|
uid_t uid = (flag & AT_EACCESS) ? __geteuid () : __getuid ();
|
|
|
|
/* The super-user can read and write any file, and execute any file
|
|
that anyone can execute. */
|
|
if (uid == 0 && ((mode & X_OK) == 0
|
|
|| (stats.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))))
|
|
return 0;
|
|
|
|
int granted = (uid == stats.st_uid
|
|
? (unsigned int) (stats.st_mode & (mode << 6)) >> 6
|
|
: (stats.st_gid == ((flag & AT_EACCESS)
|
|
? __getegid () : __getgid ())
|
|
|| __group_member (stats.st_gid))
|
|
? (unsigned int) (stats.st_mode & (mode << 3)) >> 3
|
|
: (stats.st_mode & mode));
|
|
|
|
if (granted == mode)
|
|
return 0;
|
|
|
|
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EACCES);
|
|
}
|