[src/trunk]: src Make flock(2) more robust to invalid operation, such as

[njoly <njoly%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d080f933e9b6
branches:  trunk
changeset: 748593:d080f933e9b6
user:      njoly <njoly%NetBSD.org@localhost>
date:      Wed Oct 28 18:24:44 2009 +0000

description:
Make flock(2) more robust to invalid operation, such as
(LOCK_EX|LOCK_SH).

diffstat:

 lib/libc/sys/flock.2   |   6 +++---
 sys/kern/sys_descrip.c |  18 +++++++++++-------
 2 files changed, 14 insertions(+), 10 deletions(-)

diffs (76 lines):

diff -r a4f852cecf88 -r d080f933e9b6 lib/libc/sys/flock.2
--- a/lib/libc/sys/flock.2      Wed Oct 28 18:20:41 2009 +0000
+++ b/lib/libc/sys/flock.2      Wed Oct 28 18:24:44 2009 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: flock.2,v 1.19 2004/05/13 10:20:58 wiz Exp $
+.\"    $NetBSD: flock.2,v 1.20 2009/10/28 18:24:44 njoly Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)flock.2    8.2 (Berkeley) 12/11/93
 .\"
-.Dd December 11, 1993
+.Dd October 26, 2009
 .Dt FLOCK 2
 .Os
 .Sh NAME
@@ -136,7 +136,7 @@
 .It Bq Er EINVAL
 The argument
 .Fa operation
-does not include one of
+does not include exactly one of
 .Dv LOCK_EX ,
 .Dv LOCK_SH
 or
diff -r a4f852cecf88 -r d080f933e9b6 sys/kern/sys_descrip.c
--- a/sys/kern/sys_descrip.c    Wed Oct 28 18:20:41 2009 +0000
+++ b/sys/kern/sys_descrip.c    Wed Oct 28 18:24:44 2009 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_descrip.c,v 1.16 2009/06/10 23:48:10 yamt Exp $    */
+/*     $NetBSD: sys_descrip.c,v 1.17 2009/10/28 18:24:44 njoly Exp $   */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_descrip.c,v 1.16 2009/06/10 23:48:10 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_descrip.c,v 1.17 2009/10/28 18:24:44 njoly Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -585,21 +585,25 @@
        lf.l_whence = SEEK_SET;
        lf.l_start = 0;
        lf.l_len = 0;
-       if (how & LOCK_UN) {
+
+       switch (how & ~LOCK_NB) {
+       case LOCK_UN:
                lf.l_type = F_UNLCK;
                atomic_and_uint(&fp->f_flag, ~FHASLOCK);
                error = VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
                fd_putfile(fd);
                return error;
-       }
-       if (how & LOCK_EX) {
+       case LOCK_EX:
                lf.l_type = F_WRLCK;
-       } else if (how & LOCK_SH) {
+               break;
+       case LOCK_SH:
                lf.l_type = F_RDLCK;
-       } else {
+               break;
+       default:
                fd_putfile(fd);
                return EINVAL;
        }
+
        atomic_or_uint(&fp->f_flag, FHASLOCK);
        p = curproc;
        if (how & LOCK_NB) {