lkml.org 
[lkml]   [2000]   [Jan]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH] root-hopping for pre-2.3.41-3
    Date
    Followup to:  <20000126011602.A1070@win.tue.nl>
    By author: Guest section DW <dwguest@win.tue.nl>
    In newsgroup: linux.dev.kernel
    >
    > and Peter answered
    >
    > > > Right... everyone on the old / move to the new /, although I guess
    > > > that's technically not 100% necessary.
    >
    > but I wonder.
    > Usually in such a situation not many processes will be around, but still..
    > It would be strange if the interpretation of paths suddenly changed for
    > processes other than the one doing this pivot_root.
    > So, I would prefer these old processes all to remain where they are,
    > with the same root inode (that just got a new name, namely /old_root).
    >
    > Thus, the only process that would get the new / as root would be the
    > process doing this pivot_root() (and perhaps init?).
    >

    I think this really is the right solution... usually the process doing
    this will *be* init. There are other things that need to be done,
    too, like replacing the console fd's after the remount (otherwise you
    will hold initrd busy by virtue of having /dev/console open.)

    I therefore conclude that doing automatic stuff is pointless and
    probably harmful. The recommended sequence for root-switching will
    then look something like (error checking omitted):

    chdir("/oldroot");
    pivot_root("/newroot", "/oldroot");
    chroot(".");
    new_console = open("/dev/console", O_RDWR);
    dup2(new_console, 0);
    dup2(new_console, 1);
    dup2(new_console, 2);
    close(new_console);

    execl("/sbin/init", "init", 0);
    --
    <hpa@transmeta.com> at work, <hpa@zytor.com> in private!
    "Unix gives you enough rope to shoot yourself in the foot."

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:56    [W:0.021 / U:0.368 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site