Messages in this thread | | | Date | Mon, 20 Feb 2006 09:05:59 +0800 (WST) | From | Ian Kent <> | Subject | Re: [PATCH] autofs4 - fix comms packet struct size |
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On Sun, 19 Feb 2006, Christoph Hellwig wrote:
> On Sun, Feb 19, 2006 at 10:11:31PM +0800, Ian Kent wrote: > > > > Set userspace communication struct fields to fixed size. > > > > Signed-off-by: Ian Kent <raven@themaw.net> > > > > --- linux-2.6.16-rc3-mm1/include/linux/auto_fs4.h.fix-v5-packet-size 2006-02-17 19:15:49.000000000 +0800 > > +++ linux-2.6.16-rc3-mm1/include/linux/auto_fs4.h 2006-02-17 19:12:09.000000000 +0800 > > @@ -65,10 +65,10 @@ struct autofs_v5_packet { > > autofs_wqt_t wait_queue_token; > > Hiding types in user visible structures behind typedefs is bad. > What type is behind this? If this is not an __u32 you have > a padding issue.
This has been an occassion problem for a long time. Since it dates back to way before version 4 I have always been reluctant to change it. I'd rather leave it as is unless you really can't accept it.
> > > __u32 dev; > > __u64 ino; > > - uid_t uid; > > - gid_t gid; > > - pid_t pid; > > - pid_t tgid; > > + __u64 uid; > > + __u64 gid; > > + __u64 pid; > > + __u64 tgid; > > These should be 32bit values.
OK. But will they be 32 bit for the life of this struct?
Once userspace programs are using this it can't ever change.
> > > int len; > > this should become a fixed-size type aswell.
OK. That shouldn't cause a problem. I'll change that also.
> > > char name[NAME_MAX+1]; > > }; > > --- linux-2.6.16-rc3-mm1/fs/autofs4/autofs_i.h.fix-v5-packet-size 2006-02-17 19:17:03.000000000 +0800 > > +++ linux-2.6.16-rc3-mm1/fs/autofs4/autofs_i.h 2006-02-17 19:17:25.000000000 +0800 > > @@ -79,10 +79,10 @@ struct autofs_wait_queue { > > char *name; > > u32 dev; > > u64 ino; > > - uid_t uid; > > - gid_t gid; > > - pid_t pid; > > - pid_t tgid; > > + u64 uid; > > + u64 gid; > > + u64 pid; > > + u64 tgid; > > /* This is for status reporting upon return */ > > int status; > > atomic_t notified; > > This is an in-kernel structure, isn't it? No need to use u64 here.
Yes, I was thinking the same thing when I did it. I'll fix that.
Thanks Christoph.
Ian
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