#!@GENTOO_PORTAGE_EBASH@
# Copyright 1999-2019 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

# Fabian Groffen <grobian@gentoo.org> -- 2007-03-10
# Enters the prefix environment by starting a login shell from the
# prefix.  The SHELL environment variable is elevated in order to make
# applications that start login shells to work, such as `screen`.

# if you come from a substantially polluted environment (another
# Prefix), a cleanup as follows resolves most oddities I've ever seen:
# env -i HOME=$HOME TERM=$TERM USER=$USER $SHELL -l
# hence this script starts the Prefix shell like this

if [[ ${SHELL#@GENTOO_PORTAGE_EPREFIX@} != ${SHELL} ]]
then
	echo "You appear to be in prefix already (SHELL=${SHELL})" > /dev/stderr
	exit -1
elif [[ ${SHELL#@GENTOO_PORTAGE_BPREFIX@} != ${SHELL} ]] &&
	 [[ ${EPREFIX-unset} == '@GENTOO_PORTAGE_EPREFIX@' ]]
then
	echo "You appear to be in stacked prefix already (EPREFIX=${EPREFIX})" > /dev/stderr
	exit -1
fi

# What is our prefix?
EPREFIX@=@'@GENTOO_PORTAGE_EPREFIX@'
BPREFIX@=@'@GENTOO_PORTAGE_BPREFIX@'

# not all systems have the same location for shells, however what it
# boils down to, is that we need to know what the shell is, and then we
# can find it in the bin dir of our prefix
for SHELL in \
	"${EPREFIX}/bin/${SHELL##*/}" \
	"${BPREFIX}/bin/${SHELL##*/}" \
	${SHELL##*/}
do
	[[ ${SHELL} == */* && -x ${SHELL} ]] && break
done

# check if the shell exists
if [[ ${SHELL} != */* ]]
then
	echo "Failed to find the Prefix shell, this is probably" > /dev/stderr
	echo "because you didn't emerge the shell ${SHELL}" > /dev/stderr
	exit 1
fi

# set the prefix shell in the environment
export SHELL

# give a small notice
echo "Entering Gentoo Prefix ${EPREFIX}"
# start the login shell, clean the entire environment but what's needed
RETAIN="HOME=$HOME TERM=$TERM USER=$USER SHELL=$SHELL"
# PROFILEREAD is necessary on SUSE not to wipe the env on shell start
[[ -n ${PROFILEREAD} ]] && RETAIN+=" PROFILEREAD=$PROFILEREAD"
# ssh-agent is handy to keep, of if set, inherit it
[[ -n ${SSH_AUTH_SOCK} ]] && RETAIN+=" SSH_AUTH_SOCK=$SSH_AUTH_SOCK"
# if we're on some X terminal, makes sense to inherit that too
[[ -n ${DISPLAY} ]] && RETAIN+=" DISPLAY=$DISPLAY"
if [[ -d /proc/registry ]]; then # we're on Cygwin
	# crucial to Windows but cannot be restored, see
	# https://cygwin.com/ml/cygwin/2019-08/msg00072.html
	[[ -n ${SYSTEMDRIVE} ]] && RETAIN+=" SYSTEMDRIVE=$SYSTEMDRIVE"
	# COMSPEC is to native Windows what SHELL is to *nix
	[[ -n ${COMSPEC} ]] && RETAIN+=" COMSPEC=$COMSPEC"
	# some Windows programs (e.g. devenv.exe) need TMP or TEMP
	[[ -n ${TEMP} ]] && RETAIN+=" TEMP=$TEMP"
fi
# do it!
if [[ ${SHELL#${EPREFIX}} != ${SHELL} ]] ; then
	'@GENTOO_PORTAGE_EENV@' -i $RETAIN $SHELL -l
elif [[ ' bash ' == *" ${SHELL##*/} "* ]] ; then
	# shell coming from different prefix would load it's own
	# etc/profile upon -l, so we have to override
	'@GENTOO_PORTAGE_EENV@' -i ${RETAIN} "${SHELL}" --rcfile "${EPREFIX}"/etc/prefix-stack.bash_login -i
else
	echo "Only bash is supported with stacked Prefix (you have ${SHELL##*/}), sorry!" > /dev/stderr
	exit 1
fi
# and leave a message when we exit... the shell might return non-zero
# without having real problems, so don't send alarming messages about
# that
echo "Leaving Gentoo Prefix with exit status $?"