I am trying to get Live Upgrade better by reimplementing some parts of
the code. What I am not sure of is whether is it safe to do a copy of
non global zone imports (filesystems dedicated to a zone in its config)
from the global zone.

This is existing code (lucopy.sh:1808, install-nv-clone):

1808    (
1809        fgrep -xv $mountpoint /tmp/lucopy.zonefs.$$
1810        cat /tmp/lucopy.zoneipd.$$
1811    ) | sed 's+.*+^&/+' |
1812    zlogin $ozonename \
1813        "cat > /tmp/lucopy.excl.$$; \
1814        (
1815            if [ -s /tmp/lucopy.excl.$$ ]; then
1816                cd $zroot$mountpoint && \
1817                find . -depth -print | \
1818                egrep -vf /tmp/lucopy.excl.$$ | \
1819                    cpio -ocmP@
1820            else
1821                cd $zroot$mountpoint && \
1822                  find . -depth -print | cpio -ocmP@
1823            fi
1824        )" |
1825    ( cd $tdir && cpio -icdmP@ )
1826    lulib_unmount_pathname $tdir

To describe it, I would say that it will zlogin into the non global
zone, generates there a listing which it sends onto stdin of cpio which
writes an archive on its stdout. That archive is directed to the
stdin of cpio running _OUTSIDE_ the zone (in the global zone) which
finally expands it and writes it to a target directory.

Unfortunatelly few lines above there is this comment:

1769    # Mount each non-lofs zone import in a temporary location
1770    # and copy over the bits that belong there, extracted from
1771    # the running zone.  We are now reaching through zone-
1772    # controlled paths and thus must be extremely careful.
1773    # Direct copies are not safe.

And the question is: What can happen if I simply will not generate the
listing and the archive inside the zone but will do it in the global
zone and using 'cpio -p'?

If I generalize the problem a little bit more I would like to know your
opinion about my idea of copying whole BE including zones in just one
'cpio -p'. Why it wouldn't work, please?

Thank you very much for your any reply
Martin Rehak
zones-discuss mailing list

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