Subject: Re: [PATCH v3 2/6] ci/lib-docker: preserve required environment variables

From: Danh Doan <[email-masked]>
Date: Fri, 3 Apr 2020 17:09:31 +0700

On 2020-04-03 10:22:54+0200, SZEDER Gábor <[email-masked]> wrote:
> On Thu, Apr 02, 2020 at 08:04:01PM +0700, Đoàn Trần Công Danh wrote:
> > We're using "su -m" to preserve environment variables in the shell run
> > by "su". But, that options will be ignored while "-l" (aka "--login") is
> > specified.
> 
> This is not true.  See any previous runs of the 32 bit Linux job,
> which worked as expected, because none of these environment variables
> were cleared.

Different su have different behavior when combine "-m" and "-l"

util-linux's su has this as far as 60541961f, (docs: improve grammar,
wording and formatting of su man page, 2013-10-12)

       -m, -p, --preserve-environment
              Preserve the entire environment, i.e., it does not set HOME,
              SHELL, USER nor LOGNAME.  This option is ignored if the option
              --login is specified.

https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/tree/login-utils/su.1#n120

Ubuntu (our Linux32 builder), ships su by shadow-utils:

	Note that the default behavior for the environment is the following:
		The $HOME, $SHELL, $USER, $LOGNAME, $PATH,
		and $IFS environment variables are reset.

		If --login is not used, the environment is copied,
		except for the variables above.

		If --login is used, the $TERM, $COLORTERM, $DISPLAY, and
		$XAUTHORITY environment variables are copied if they were set.

There're no mentions of other variables, I _think_ our Linux32 works
by accident.

Alpine ships su from busybox, this su ignores "-m" if "-l" is set.

-- 
Danh