Reviewed by: hackers@freebsd.org in general

Obtained from: Whistle Communications tree

Add an option to the way UFS works dependent on the SUID bit of directories
This changes makes things a whole lot simpler on systems running as
fileservers for PCs and MACS. to enable the new code you must
1/ enable option SUIDDIR on the kernel.
2/ mount the filesystem with option suiddir.
hopefully this makes it difficult enough for people to
do this accidentally.
see the new chmod(2) man page for detailed info.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/libc/sys/mount.2 b/lib/libc/sys/mount.2
index d1199c2..25a2d8c 100644
--- a/lib/libc/sys/mount.2
+++ b/lib/libc/sys/mount.2
@@ -89,6 +89,8 @@ Do not honor setuid or setgid bits on files when executing them.
 Disable update of file access times.
 .It Dv MNT_NODEV
 Do not interpret special files on the filesystem.
+.It Dv MNT_SUIDDIR
+Directories with the SUID bit set chown new files to their own owner.
 .It Dv MNT_SYNCHRONOUS
 All I/O to the filesystem should be done synchronously.
 .It Dv MNT_ASYNC
@@ -153,6 +155,16 @@ even if files are still active.
 Active special devices continue to work,
 but any further accesses to any other active files result in errors
 even if the filesystem is later remounted.
+.Pp
+The
+.Dv MNT_SUIDDIR
+option requires the SUIDDIR option to have been compiled into the kernel
+to have any effect.
+See the
+.Xr mount 8 
+and
+.Xr chmod 2
+pages for more information.
 .Sh RETURN VALUES
 The
 .Fn mount