fs: add ksys_chroot() helper; remove-in kernel calls to sys_chroot()

Using this helper allows us to avoid the in-kernel calls to the
sys_chroot() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_chroot().

In the near future, the fs-external callers of ksys_chroot() should be
converted to use kern_path()/set_fs_root() directly. Then ksys_chroot()
can be moved within sys_chroot() again.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-11 11:34:41 +01:00
parent c7248321a3
commit a16fe33ab5
5 changed files with 11 additions and 5 deletions

View file

@ -479,7 +479,7 @@ out:
return error;
}
SYSCALL_DEFINE1(chroot, const char __user *, filename)
int ksys_chroot(const char __user *filename)
{
struct path path;
int error;
@ -512,6 +512,11 @@ out:
return error;
}
SYSCALL_DEFINE1(chroot, const char __user *, filename)
{
return ksys_chroot(filename);
}
static int chmod_common(const struct path *path, umode_t mode)
{
struct inode *inode = path->dentry->d_inode;