Re: Nagios and threads

From: Kamal R. Prasad (kamalpr_at_yahoo.com)
Date: 06/23/05

  • Next message: Andrey Simonenko: "Question about synchronization in socow_setup()" 
    Date: Thu, 23 Jun 2005 02:25:45 -0700 (PDT)
To: Daniel Eischen <deischen@freebsd.org>, Peter Edwards <peadar.edwards@gmail.com>

    --- Daniel Eischen <deischen@freebsd.org> wrote:

    > On Wed, 22 Jun 2005, Peter Edwards wrote:
    >
    > > On 6/22/05, Kamal R. Prasad <kamalpr@yahoo.com>
    > wrote:
    > > >
    > > > The child process should be able to call any
    > system
    > > > calls it likes -without assuming that pthreads
    > from
    > > > the parent process have been copied over to the
    > child
    > > > process. I spose most implementations support
    > that.
    > > >
    > >
    > > There's more to it than system calls, though (most
    > (all?) of which
    > > will be async-signal-safe anyway). Simple example:
    > any lock that the
    > > libc implementation needs to provide its
    > functionality may be
    > > arbitrarily locked by some other thread: eg, one
    > thread calls malloc()
    > > as another calls fork(): the original thread
    > ceases to exist in the
    > > child while holding a lock in malloc, leaving
    > malloc() unusable in the
    > > process.
    >
    How about doing some cleanup in a pthread_atfork()
    routine? It can be done by the user or a libc/X stub
    that gets called implicitly.

    > We do protect the malloc lock across a fork(), but
    > that's it.
    >
    Isn't it possible that an application may genuinely
    want to fork() out a child and not exec() another
    process.?

    regards
    -kamal

    > --
    > DE
    >
    >

    ------------------------------------------------------------
    Kamal R. Prasad
    UNIX systems consultant
    http://members.fortunecity.com/kamalp
    kamalp@acm.org

    In theory, there is no difference between theory and practice. In practice, there is.
    ------------------------------------------------------------

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  • Next message: Andrey Simonenko: "Question about synchronization in socow_setup()"

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