vfs: add faccessat2 syscall

POSIX defines faccessat() as having a fourth "flags" argument, while the
linux syscall doesn't have it.  Glibc tries to emulate AT_EACCESS and
AT_SYMLINK_NOFOLLOW, but AT_EACCESS emulation is broken.

Add a new faccessat(2) syscall with the added flags argument and implement
both flags.

The value of AT_EACCESS is defined in glibc headers to be the same as
AT_REMOVEDIR.  Use this value for the kernel interface as well, together
with the explanatory comment.

Also add AT_EMPTY_PATH support, which is not documented by POSIX, but can
be useful and is trivial to implement.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

This commit is contained in:

Miklos Szeredi

2020-05-14 16:44:25 +02:00

parent 55923e4d7d

commit c8ffd8bcdd

23 changed files with 62 additions and 13 deletions

arch/alpha/kernel/syscalls/syscall.tbl

View File

@@ -477,3 +477,4 @@
 # 545 reserved for clone3
 	common	openat2				sys_openat2
 	common	pidfd_getfd			sys_pidfd_getfd
 	common	faccessat2			sys_faccessat2