Tweaks utimensat/futimens handling to always update ctime, even when both

atime and mtime are UTIME_OMIT (at least for ufs, tmpfs, and ext2fs), and
to correctly handle a timestamp of -1.

ok millert@

1 files changed, 11 insertions, 14 deletions

diff --git a/lib/libc/sys/utimes.2 b/lib/libc/sys/utimes.2
index 5dce0004265..f3d15d5190c 100644
--- a/lib/libc/sys/utimes.2
+++ b/lib/libc/sys/utimes.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: utimes.2,v 1.24 2015/02/27 23:56:03 millert Exp $
+.\"	$OpenBSD: utimes.2,v 1.25 2015/04/17 04:43:20 guenther Exp $
 .\"	$NetBSD: utimes.2,v 1.9 1996/04/23 10:34:16 mycroft Exp $
 .\"
 .\" Copyright (c) 1990, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)utimes.2	8.1 (Berkeley) 6/4/93
 .\"
-.Dd $Mdocdate: February 27 2015 $
+.Dd $Mdocdate: April 17 2015 $
 .Dt UTIMES 2
 .Os
 .Sh NAME
@@ -75,8 +75,7 @@ The access time is set to the value of the first element, and the
 modification time is set to the value of the second element.
 The caller must be the owner of the file or be the superuser.
 .Pp
-In either case, the inode-change-time of the file is set to the current
-time.
+In either case, the file status change time is set to the current time.
 .Pp
 The
 .Fn utimensat
@@ -294,15 +293,13 @@ and
 function calls appeared in
 .Ox 5.0 .
 .Sh CAVEATS
-.St -p1003.1-2008
-specifies that
-.Fn utimensat
-and
-.Fn futimens
-shall mark the last file status change timestamp (i.e.\&
-.Fa st_ctim )
-for update upon successful completion.
-However, currently some filesystems (e.g. UFS)
-will not do so if
+Some filesystems, such as FAT, use the same timestamp for both
+modification and file status change;
+on those filesystems, the file status change timestamp will not be
+updated if
 .Dv UTIME_OMIT
 is specified for the modification timestamp argument.
+Similarly, on NFS the file status change timestamp will not be
+updated if
+.Dv UTIME_OMIT
+is specified for both the access and the modification timestamp arguments.