In the email from Friday, 10 June 2022 08:14:19 +03 user Jan Kiszka wrote:

> On 10.06.22 05:19, Uladzimir Bely wrote:

> > Changes in 342a751e introduced a regression when error from 'find'

> > makes helper script early exit (with -1 error code) just after an

> > attempt to assign ROOT_DEV_SLAVE variable. So, the last partition

> > remained not resized.

> >

> > Passing 'find' output to 'head -1' masks possible error from 'find'

> > without breaking the logic and continues the script execution.

> >

> > Signed-off-by: Uladzimir Bely <ubely@ilbers.de>

> > ---

> >

> >  .../expand-on-first-boot/files/expand-last-partition.sh         | 2 +-

> >  1 file changed, 1 insertion(+), 1 deletion(-)

> >

> > diff --git

> > a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.s

> > h

> > b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.s

> > h index f3e29a1c..934a014f 100755

> > ---

> > a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.s

> > h +++

> > b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.s

> > h @@ -11,7 +11,7 @@ set -e

> >

> >  ROOT_DEV="$(findmnt / -o source -n)"

> >  ROOT_DEV_NAME=${ROOT_DEV##*/}

> >

> > -ROOT_DEV_SLAVE=$(find /sys/block/"${ROOT_DEV_NAME}"/slaves -mindepth 1

> > -print -quit 2>/dev/null) +ROOT_DEV_SLAVE=$(find

> > /sys/block/"${ROOT_DEV_NAME}"/slaves -mindepth 1 -print -quit 2>/dev/null

> > | head -1)>

> >  if [ -n "${ROOT_DEV_SLAVE}" ]; then

> > 

> >      ROOT_DEV=/dev/${ROOT_DEV_SLAVE##*/}

> > 

> >  fi

>

> "-quit" is supposed to obsolete "head -1". Feel free to prove me wrong,

> but that was the reason for dropping it.

>

> Jan

Yes, "-quit" makes 'find' to exit after first match. But if nothing found, the return code of 'find' is "-1" and due to script's "set -e" it just exits.

An example that demonstrates the behaviour (on raspberry):

root@isar:~# cat /boot/test.sh  
#!/bin/sh

set -e

echo "1: start"
ROOT_DEV="$(findmnt / -o source -n)"
echo "2: ROOT_DEV=${ROOT_DEV}"
ROOT_DEV_NAME=${ROOT_DEV##*/}
echo "3: ROOT_DEV_NAME=${ROOT_DEV_NAME}"
ROOT_DEV_SLAVE=$(find /sys/block/"${ROOT_DEV_NAME}"/slaves -mindepth 1 -print -quit 2>/dev/null)
echo "4: ROOT_DEV_SLAVE=${ROOT_DEV_SLAVE}"
root@isar:~# sh /boot/test.sh  
1: start
2: ROOT_DEV=/dev/mmcblk0p2
3: ROOT_DEV_NAME=mmcblk0p2
root@isar:~# echo $?
1
root@isar:~# ls /sys/block/ | grep mmc
mmcblk0
root@isar:~#

So, the easiest way to mask error returned by 'find' is to use something like 'head -1' or 'tee /dev/null'. In this case script just continues with empty ROOT_DEV_SLAVE.

--

Uladzimir Bely