app-portage/prefix-toolkit: new packageprefix-toolkit-0

* For any Gentoo Prefix, provides the 'startprefix' script, and should
provide some 'runprefix' script later on, as inspired in
Bug: https://bugs.gentoo.org/673816

* For base Gentoo Prefix (as in "not stacked"), provides the
'prefix-stack-setup' script, superseding app-portage/prefix-chain-setup,
does force the prefix-stack implit USE flag in the stacked Prefix.
* For stacked Gentoo Prefix (set up using 'prefix-stack-setup'),
provides the toolchain wrapper, superseding sys-apps/prefix-chain-utils.
Bug: https://bugs.gentoo.org/658572

Closes: https://bugs.gentoo.org/509142
Package-Manager: Portage-2.3.51, Repoman-2.3.11
Signed-off-by: Michael Haubenwallner <haubi@gentoo.org>

(cherry picked from commit 84b9f582e8c8db69a3b3677de702c7cc00ac3dab)

1 files changed, 76 insertions, 0 deletions

diff --git a/startprefix b/startprefix
new file mode 100644
index 0000000..89ce10f
--- /dev/null
+++ b/startprefix
@@ -0,0 +1,76 @@
+#!@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"
+# 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 $?"