[arch-releng] [PATCH 11/12] [archiso] Update archiso_shutdown hook

[Gerardo Exequiel Pozzi]

On 02/23/2012 12:22 PM, Dave Reisner wrote:
> On Thu, Feb 23, 2012 at 12:13:53PM -0300, Gerardo Exequiel Pozzi wrote:
>> On 02/23/2012 11:55 AM, Dave Reisner wrote:
>>> On Thu, Feb 23, 2012 at 12:30:50AM -0300, Gerardo Exequiel Pozzi wrote:
>>>> * Add libraries from /usr/lib and /sbin/losetup.
>>>> * Use used_block_devices to detach loop devices.
>>>>
>>>> Signed-off-by: Gerardo Exequiel Pozzi<vmlinuz386 at yahoo.com.ar>
>>>> ---
>>>>   archiso/archiso_shutdown       |   13 +++++--------
>>>>   archiso/hooks/archiso_shutdown |   10 +++++-----
>>>>   2 files changed, 10 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/archiso/archiso_shutdown b/archiso/archiso_shutdown
>>>> index 26220a6..c430014 100644
>>>> --- a/archiso/archiso_shutdown
>>>> +++ b/archiso/archiso_shutdown
>>>> @@ -10,10 +10,8 @@ umount $(mount | awk '$3 ~/^\/oldroot/ {print $3}' | sort -r)
>>>>   # Remove all dm-snapshot devices.
>>>>   dmsetup remove_all
>>>>
>>>> -# Remove all loopback devices made for dm-snapshots devices
>>>> -# other misc loops like used for pure squashfs images
>>>> -# and unmount/detach *.fs.sfs images.
>>>> -for _lup in $(ls -r /dev/loop[1-9][0-9][0-9]); do
>>>> +# Remove all loopback devices.
>>>> +for _lup in $(grep ^/dev/loop /oldrun/archiso/used_block_devices | tac); do
>>> Eek. Please don't do this. I have bad experiences with tac, particularly
>>> in initscripts on shutdown, because there was nowhere for tac to write
>>> to (it creates a temporary file when it reads from a pipe). "for" is no
>>> way to iterate over lines of output, either. It's a little more long
>>> winded, but I'm always in favor of doing this "correctly":
>>>
>>> mapfile -t loopdevs</oldrun/archiso/used_block_devices
>>> for (( i=${loopdevs[*]}-1; i>=0; i-- )); do
>>>    if [[ ${loopdevs[i]} = /dev/loop* ]]&&   ! loosetup -d "${loopdevs[i]}" 2>/dev/null; then
>>>      umount -d "${loopdevs[i]}"
>>>    fi
>>> done
>>> unset loopdevs i
>> True about tac (from coreutils) but tac (from busybox) looks like
>> does not use tempfile [#1]
>>
>> The problem here is that such shell code is for bash, here is ash
>> from busybox.
>>
>> Thanks for review.
>>
> derp. carry on.
>

Hehe, anyway, in a future, I want to use losetup --detach-all (new in 
2.21), then umount -d, without looking at the list. For now, this code 
just works and makes posible to use current losetup (booting with 
extra/workaround bootparams of course).

Thanks you.

-- 
Gerardo Exequiel Pozzi
\cos^2\alpha + \sin^2\alpha = 1