Re: syscall: sys_promote

From: Qi Yong (qiyong_at_fc-cn.com)
Date: 08/31/05

  • Next message: Florian Weimer: "Re: Atheros and rt2x00 driver" 
    Date:	Wed, 31 Aug 2005 15:53:18 +0800
To: Ulrich Drepper <drepper@gmail.com>

    Ulrich Drepper wrote:

    >On 8/29/05, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
    >
    >
    >>Fixing it might be useful in some obscure cases anyway - POSIX threads
    >>might benefit from it too, providing the functionality of changing all
    >>thread uids at once isnt triggered for sensible threaded app behaviour.
    >>
    >>
    >
    >I would very much like to see that fixed. Currently we have to change
    >the UIDs/GIDs at userlevel with cross-thread calls implemented via
    >signals. This is user observable which is not correct. This is
    >probably the last area where we're not 100% POSIX compliant.
    >
    >As for adding this proposed syscall: it can only lead to chaos. All
    >kinds of user code correctly so assumes the IDs don't change over the
    >lifetime of a process. The solution for the problem has been
    >
    >
    After a user shell is promoted to root, its prompt is still $ instead of
    #. But why do we care?

    >mentioned as well: re-exec. This will require some code rewrite on
    >the side of the applications but any decent daemon is hopefully soon
    >
    >

    OK, so any decent processes should not break into other processes'
    address space.
    And let us use non-preemptive multitasking?

    >support re-exec anyway for another reason: re-randomization of the
    >address space. What good does address space randomization do if the
    >machines and programs are so damn stable that they keep running for
    >months at a time? nscd supports this now and I think openssh as well.
    >
    >

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  • Next message: Florian Weimer: "Re: Atheros and rt2x00 driver"