Re: [PATCH v4 1/5] expand-on-first-boot: support resizing a btrfs

["Roberto A. Foglietta" <roberto.foglietta@gmail.com>]

On Wed, 14 Dec 2022 at 04:33, Moessbauer, Felix
<felix.moessbauer@siemens.com> wrote:

> > What Felix tried to tell you was to use a variable like in my patch
> > but using TMPDIR as the name of the variable. When that variable is
> > not defined then "" is the default value. Now, what happens to mktemp
> > when it is called with -p ""? Nothing bad, it simply performs without
> > -p. Why was Felix pointing this out? Probably because in my patch tmp
> > variable should be set if null but using mktemp this is not necessary
> > anymore.
>
> No! Please also stop guessing what I could have meant and wait at least
> a day for me to answer (instead of trying to convince others of your
> interpretation of my opinion).
>
> The way Henning implemented it is exactly how I meant it.
>
> As this whole thing runs as a systemd service, a user can easily set
> TMPDIR via a drop-in file.
>

Felix, thanks for the clarification, the behaviour is aligned with the
manual but expliciting the variable would have been easier to read
without checking the manal

       -p DIR, --tmpdir[=DIR]
              interpret TEMPLATE relative to DIR; if DIR is not
specified, use $TMPDIR if set, else /tmp.  With this option, TEMPLATE
must not be an absolute name; unlike with  -t,  TEMPLATE  may  contain
              slashes, but mktemp creates only the final component

This is the output of the command without, with and with specified
TMPDIR variable

roberto:~/robang74/isar-nvidia-debian$ echo "x$TMPDIR"
x
roberto:~/robang74/isar-nvidia-debian$ mktemp -d -p "" ciao.XXX
/tmp/ciao.wLK
roberto:~/robang74/isar-nvidia-debian$ export TMPDIR=/dev/shm
roberto:~/robang74/isar-nvidia-debian$ mktemp -d -p "" ciao.XXX
/dev/shm/ciao.fYb
roberto:~/robang74/isar-nvidia-debian$ mktemp -d  ciao.XXX
ciao.Lwp
roberto:~/robang74/isar-nvidia-debian$ mktemp -d -p "$TMPDIR" ciao.XXX
/dev/shm/ciao.gw1

Cheers, R-