Wiadomość napisana przez Pawel Jakub Dawidek w dniu 2009-11-04, o
godz. 08:04:
On Wed, Nov 04, 2009 at 06:48:34AM +0000, Edward Tomasz Napierala
wrote:
Author: trasz
Date: Wed Nov 4 06:48:34 2009
New Revision: 198874
URL: http://svn.freebsd.org/changeset/base/198874
Log:
Make sure we don't end up with VAPPEND without VWRITE, if someone
calls open(2)
like this: open(..., O_APPEND).
Modified:
head/sys/kern/vfs_vnops.c
Modified: head/sys/kern/vfs_vnops.c
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=====================================================================
--- head/sys/kern/vfs_vnops.c Wed Nov 4 06:47:14 2009 (r198873)
+++ head/sys/kern/vfs_vnops.c Wed Nov 4 06:48:34 2009 (r198874)
@@ -213,7 +213,7 @@ restart:
if (fmode & FEXEC)
accmode |= VEXEC;
if (fmode & O_APPEND)
- accmode |= VAPPEND;
+ accmode |= VWRITE | VAPPEND;
#ifdef MAC
error = mac_vnode_check_open(cred, vp, accmode);
if (error)
Why? If someone does O_APPEND only we don't want to give him write
access...
As it is now, VAPPEND is not a real V* flag - it's a kind of modifier
to VWRITE.
Which means that it doesn't really make sense, from the conceptual
point of view,
to have VAPPEND without VWRITE being set at the same time. This
doesn't break
things right now - at least I don't know about any such breakage - but
in the
future I'd like to have a few KASSERTs to verify that VAPPEND is never
specified
without VWRITE, just to make sure something unexpected doesn't happen
somewhere.
As it is now, doing open(..., O_APPEND) will result in a
filedescriptor open
for... reading. So, the change above would change the behaviour.
What about
something like this instead:
Index: vfs_vnops.c
===================================================================
--- vfs_vnops.c (revision 198876)
+++ vfs_vnops.c (working copy)
@@ -212,7 +212,7 @@
accmode |= VREAD;
if (fmode & FEXEC)
accmode |= VEXEC;
- if (fmode & O_APPEND)
+ if ((fmode & O_APPEND) && (fmode & FWRITE))
accmode |= VAPPEND;
#ifdef MAC
error = mac_vnode_check_open(cred, vp, accmode);
--
If you cut off my head, what would I say? Me and my head, or me and
my body?
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