Re: [RFC] proposed IPC changes to support 32-bit UIDs

msmail@colorfullife.com
Wed, 1 Dec 1999 08:11:48 -0500 (EST)

>
> Hello. In my latest set of 32-bit UID support patches, I've changed the
> msgctl(), semctl(), and shmctl() functions to no longer use the same
> structures for both kernel and user space (for IPC_STAT, IPC_SET,
> MSG_STAT, SEM_STAT, and SHM_STAT). Instead, the msg_queue, semid_ds, and
> shmid_ds structures are considered private to the kernel, and there are
> now 2 sets of structures for communicating with user space:
>
> user_msqid_ds, user_semid_ds, user_shmid_ds
> and
> old_user_msqid_ds, old_user_semid_ds, old_user_shmid_ds
>
we cannot rename the user space structures:
msqid_ds,... are predefined names from the SUS standard, we
must rename the kernel structures.

and: I don't know if the new version or the old version should
be the default:
Many applications don't care about the uid field,
but with your patch applied, all recompiled programs
would fail on 2.2 kernels.

But I agree that we must change something (the user space
code that I use to increase the message queue size > 64 kB
is "interesting")

> rather than toss all the new code into the already hairy msgctl(),
> semctl(), and shmctl() functions.

or: we could replace the "copy_to_user()" functions.
ie. "copy_semid_ds_to_user(src,dest,version)"
version=0 -> automatically convert
version=1 -> normal copy_to_user

--
	Manfred


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