From 2555cc55b0b40d4b6843fdfbd5c3bb34728ed13b Mon Sep 17 00:00:00 2001
From: ptrcnull <git@ptrcnull.me>
Date: Tue, 19 Jul 2022 05:31:00 +0200
Subject: [PATCH] root-enter: upgrade to 7

---
 root-enter/APKBUILD |   6 ++-
 root-enter/enter    | 115 +++++++++++++++++++++++++++++---------------
 2 files changed, 79 insertions(+), 42 deletions(-)

diff --git a/root-enter/APKBUILD b/root-enter/APKBUILD
index ad5701f..12df9da 100644
--- a/root-enter/APKBUILD
+++ b/root-enter/APKBUILD
@@ -1,13 +1,15 @@
 # Contributor: Patrycja Rosa <alpine@ptrcnull.me>
 # Maintainer: Patrycja Rosa <alpine@ptrcnull.me>
 pkgname=root-enter
-pkgver=6
+pkgver=7
 pkgrel=0
 pkgdesc="enter chroot with mounts"
 url="https://git.ddd.rip/ptrcnull/ptrcports"
 arch="noarch"
 license="BSD-2-Clause"
+depends="execline"
 source="enter"
+builddir="$srcdir"
 options="!check"
 
 package() {
@@ -15,5 +17,5 @@ package() {
 }
 
 sha512sums="
-6e458ca9f00ce8a804bb1ff07e639a682546d3cb4e963f7fbad262625e0af74db7b94d11c2ad2fd16f7d229f4d936a80bd334216c0f1cafde4b3c650a34bf3ae  enter
+695da33b6a8eeca6e77e7afb6ea36f14b66d53afbb5408911905fbfaf93ef6e54f12819ef0af267919707f9e3c867f63fb905092c6909dd5fc68805e20849f2f  enter
 "
diff --git a/root-enter/enter b/root-enter/enter
index cc175ab..8d1e5ea 100755
--- a/root-enter/enter
+++ b/root-enter/enter
@@ -1,48 +1,83 @@
-#!/bin/sh
+#!/bin/execlineb
 
-set -e
+elgetopt "be:u:c:"
 
-[ "$(id -u)" = 0 ] || DOAS="${DOAS:-doas}"
-[ "$unshared" = 1 ] || exec $DOAS env unshared=1 unshare -m $0 "$@"
+multisubstitute {
+	importas -D "0" build ELGETOPT_b
+	importas -D "" extra_mounts ELGETOPT_e
+	importas -D "" user_arg ELGETOPT_u
+	importas -D "" command_arg ELGETOPT_c
+	importas -D "" dest 1
+	importas -i USER USER
+	importas -i HOME HOME
+}
 
-bindpoints="/etc/resolv.conf"
-user="patrycja"
-command="ash -l"
+shift
+elgetpositionals
+emptyenv -oP
 
-while getopts "be:u:c:" opt; do
-	case $opt in
-		'b') bindpoints="
-			$bindpoints
-			/home/patrycja/aports
-			/home/patrycja/packages
-			/home/patrycja/.abuild
-		" ;;
-		'e') bindpoints="$bindpoints $OPTARG" ;;
-		'u') user=$OPTARG ;;
-		'c') command=$OPTARG ;;
-		*) echo "unknown $opt" ;;
-	esac
-done
-shift $(( $OPTIND - 1 ))
+backtick -D "ash -l" command {
+	ifelse { test -n $command_arg } {
+		echo $command_arg
+	}
 
-if [ ! -d "$1" ]; then
-	echo "no such directory: $1"
+	ifelse { test $# -gt 0 } {
+		echo $@
+	}
+
+	echo ash -l
+}
+importas -ui command command
+# TODO: add -s to that when not using `su` later
+
+backtick -D "" -E user { ifelse { test -n $user_arg } { echo $user_arg } echo $USER }
+
+backtick -D "" -E build_mounts {
+	if { test $build = 1 }
+		echo "
+			${HOME}/aports
+			${HOME}/packages
+			${HOME}/.abuild
+		"
+}
+
+define -s -C bindpoints "/etc/resolv.conf ${build_mounts} ${extra_mounts}"
+
+ifelse -n { test -d $dest } {
+	foreground { echo "no such file or directory: $dest" }
 	exit 1
-fi
+}
 
-mount -t devtmpfs devtmpfs $1/dev
-mount -t tmpfs shm $1/dev/shm
-mount -t devpts devpts $1/dev/pts
-mount -t sysfs sysfs $1/sys
-mount -t proc proc $1/proc
-mount -t tmpfs tmpfs $1/tmp
-for point in $bindpoints; do
-  if [ -f $point ]; then
-    touch $1$point
-  else
-    mkdir -p $1$point
-  fi
-	mount --bind $point $1$point
-done
+ifelse -n { test -x ${dest}/bin/sh } {
+	foreground { echo "$dest does not contain executable /bin/sh" }
+	exit 1
+}
 
-chroot $1 /bin/sh -c "su $user -c '$command'"
+backtick -E uid { id -u }
+backtick -E -D "exec" sucmd { if { test $uid != 0 } echo doas }
+$sucmd
+
+unshare -m
+
+foreground { mount -t devtmpfs devtmpfs ${dest}/dev }
+foreground { mount -t tmpfs shm ${dest}/dev/shm }
+foreground { mount -t devpts devpts ${dest}/dev/pts }
+foreground { mount -t sysfs sysfs ${dest}/sys }
+foreground { mount -t proc proc ${dest}/proc }
+foreground { mount -t tmpfs tmpfs ${dest}/tmp }
+foreground {
+	forx -E point { $bindpoints }
+
+	# ensure $point exists in destination
+	ifthenelse { test -f $point } {
+		touch ${dest}${point}
+	} {
+		mkdir -p ${dest}${point}
+	}
+
+	mount --bind $point ${dest}${point}
+}
+
+chroot ${dest}
+
+su - $user -c "$command"