BaseRemoteMachine.tempdir(): add -t to mktemp to work in R/O $HOMEs

[inaky-intc]

The call to mktemp with a relative template name creates the temp directory wherever the thing logs in to, $HOME.

If $HOME is read-only, then this fails.

With this change, the temp directory is made in whatever the system considers the temporary directory to be, acknowledging TMPDIR if set (per mktemp man page) and defaulting to /tmp.

[henryiii]

That's not what I see for -t:

$ man mktemp
...
     -t prefix
             Generate a template (using the supplied prefix and TMPDIR if set) to create a filename template.
...

It seems to want a prefix.

[inaky-intc]

That's not what I see for -t:

$ man mktemp
...
     -t prefix
             Generate a template (using the supplied prefix and TMPDIR if set) to create a filename template.
...

ugh, great -- score one on one of those annoying flavour variations -- what system are you on? (kernel, Distro?); on Linux/Fedora, Ubuntu, arch, suse:

       -t     interpret TEMPLATE as a single file name component, relative  to
              a  directory:  $TMPDIR, if set; else the directory specified via
              -p; else /tmp [deprecated]

now the problem is I am seeing that deprecated thing in there and making me nervous. Per the other options, we prolly should use --tmpdir instead

  -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

however I am really interested in knowing the environment where @henryiii found a different -t option

[henryiii]

I'm on macOS, so a BSD flavor. I do see the -p option, and it seems consistent.