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From: Steven Stewart-Gallus <sstewartgallus00@mylangara.bc.ca>
To: Andy Lutomirski <luto@amacapital.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: How is pivot_root intended to be used?
Date: Thu, 04 Sep 2014 07:35:08 +0000 (GMT)	[thread overview]
Message-ID: <faeccadf18ff.5408162c@langara.bc.ca> (raw)
In-Reply-To: <5406202A.30401@amacapital.net>

Thank you, I think I will change the code to be like:

    int old_root = open("/", O_DIRECTORY);
    if (-1 == old_root) {
        perror("open");
        return EXIT_FAILURE;
    }

    if (-1 == syscall(__NR_pivot_root, ".", ".")) {
        perror("pivot_root");
        return EXIT_FAILURE;
    }

    if (-1 == fchdir(old_root)) {
        perror("fchdir");
        return EXIT_FAILURE;
    }

    if (-1 == umount2(".", MNT_DETACH)) {
        perror("umount");
        return EXIT_FAILURE;
    }

    if (-1 == close(old_root)) {
        perror("close");
        return EXIT_FAILURE;
    }

    if (-1 == chdir("/")) {
        perror("chdir");
        return EXIT_FAILURE;
    }

This seems more understandable to me and less likely to have bugs later on.

      reply	other threads:[~2014-09-04  7:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-01 21:19 How is pivot_root intended to be used? Steven Stewart-Gallus
2014-09-02 19:53 ` Andy Lutomirski
2014-09-04  7:35   ` Steven Stewart-Gallus [this message]

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