From d9779306e4fbaa1bb00ed0152c2d15ba6877c986 Mon Sep 17 00:00:00 2001
From: ptrcnull <git@ptrcnull.me>
Date: Sat, 25 Feb 2023 07:41:32 +0100
Subject: [PATCH] root-enter: upgrade to 9

go back to shell script
---
 root-enter/APKBUILD |   5 +-
 root-enter/enter    | 163 +++++++++++++++++++++++++-------------------
 2 files changed, 94 insertions(+), 74 deletions(-)

diff --git a/root-enter/APKBUILD b/root-enter/APKBUILD
index 6ba5ea3..11f7cd2 100644
--- a/root-enter/APKBUILD
+++ b/root-enter/APKBUILD
@@ -1,13 +1,12 @@
 # Contributor: Patrycja Rosa <alpine@ptrcnull.me>
 # Maintainer: Patrycja Rosa <alpine@ptrcnull.me>
 pkgname=root-enter
-pkgver=8
+pkgver=9
 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"
@@ -17,5 +16,5 @@ package() {
 }
 
 sha512sums="
-2c46100bb0c1a2a1b683d3e6070a970fcdd0bf688ccdfa3bcf4310b8f4ea0a69946a3a1b3cffec18af70eb09fb53a977a034318a7be4f103a864239880f4a1be  enter
+4a054f60ded2e17c8eca35ff30b2e23b00dba58b7208f62121ffce849502838022f61ea2a1ddc4b6c80e63cbb33e1a331f1d7aecace5ada5bd6b0ae23cd790ea  enter
 "
diff --git a/root-enter/enter b/root-enter/enter
index d49fef8..4104422 100755
--- a/root-enter/enter
+++ b/root-enter/enter
@@ -1,83 +1,104 @@
-#!/bin/execlineb
+#!/bin/sh
+set -eu
 
-elgetopt "be:u:c:"
+# make sure we're root
+if [ "$(id -u)" != 0 ]; then
+  sucmd="su -c"
+  if command -v doas >/dev/null; then
+    sucmd="doas"
+  elif command -v sudo >/dev/null; then
+    sucmd="sudo"
+  fi
 
-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
-}
+  exec $sucmd env HOME="$HOME" USERNAME="$(id -u -n)" "$0" "$@"
+fi
 
+# and make sure we're in a separate mount namespace
+if [ "$(readlink /proc/$$/ns/mnt | cut -d: -f2)" = "$(readlink /proc/1/ns/mnt | cut -d: -f2)" ]; then
+  exec unshare -m "$0" "$@"
+fi
+
+bindpoints="/etc/resolv.conf"
+command=""
+user="$USERNAME"
+
+while getopts "be:u:c:" opt; do
+  case $opt in
+    'b') bindpoints="
+      $bindpoints
+      $HOME/aports
+      $HOME/packages
+      $HOME/.abuild
+      " ;;
+    'e') bindpoints="$bindpoints $OPTARG" ;;
+    'u') user="$OPTARG" ;;
+    'c') command="$OPTARG" ;;
+    *) echo "unknown $opt" ;;
+  esac
+done
+shift $(( $OPTIND - 1 ))
+
+dest="$1"
 shift
-elgetpositionals
-emptyenv -oP
 
-backtick -D "ash -l" command {
-	ifelse { test -n $command_arg } {
-		echo $command_arg
-	}
+if [ ! -d "$dest" ]; then
+  echo "no such directory: $dest"
+  exit 1
+fi
 
-	ifelse { test $# -gt 0 } {
-		echo $@
-	}
+if [ ! -x "$dest"/bin/sh ]; then
+  echo "$dest does not contain executable /bin/sh"
+  exit 1
+fi
 
-	echo ash -l
-}
-importas -ui command command
-# TODO: add -s to that when not using `su` later
+mount -t proc proc "$dest"/proc
+mount -t sysfs sysfs "$dest"/sys
+mount -t tmpfs tmpfs "$dest"/tmp
+# some mini kernels don't have devtmpfs
+if grep -q devtmpfs /proc/filesystems; then
+  mount -t devtmpfs devtmpfs "$dest"/dev
+else
+  mount -t tmpfs tmpfs "$dest"/dev
 
-backtick -D "" -E user { ifelse { test -n $user_arg } { echo $user_arg } echo $USER }
+  if [ -x "$dest"/sbin/mdev ]; then
+    echo "devtmpfs not supported - running 'mdev -s' instead"
+    chroot "$dest" /sbin/mdev -s
+  else
+    echo "devtmpfs not supported - devices need to be created manually"
+  fi
+fi
+mount -t devpts devpts "$dest"/dev/pts
+mount -t tmpfs tmpfs "$dest"/dev/shm
 
-backtick -D "" -E build_mounts {
-	if { test $build = 1 }
-		echo "
-			${HOME}/aports
-			${HOME}/packages
-			${HOME}/.abuild
-		"
-}
+for bindpoint in $bindpoints; do
+  if [ -f "$bindpoint" ]; then
+    touch "$dest"/"$bindpoint"
+  else
+    mkdir -p "$dest"/"$bindpoint"
+  fi
 
-define -s -C bindpoints "/etc/resolv.conf ${build_mounts} ${extra_mounts}"
+  mount --bind "$bindpoint" "$dest"/"$bindpoint"
+done
 
-ifelse -n { test -d $dest } {
-	foreground { echo "no such file or directory: $dest" }
-	exit 1
-}
+# if running on chromeos, fixup symlink exec
+# https://goo.gl/8xICW6
+# https://github.com/dnschneid/crouton/commit/5cb7ad05
+if [ -e "/run/chrome" ]; then
+  if mount -n -t securityfs -o nodev,noexec,nosuid securityfs /sys/kernel/security; then
+    policies=/sys/kernel/security/chromiumos/inode_security_policies
+    if [ -d "$policies" ]; then
+      for policy in "$policies/allow_"*; do
+        printf "$(realpath "$dest")" > "$policy"
+      done
+    fi
+    umount /sys/kernel/security
+  fi
+fi
 
-ifelse -n { test -x ${dest}/bin/sh } {
-	foreground { echo "$dest does not contain executable /bin/sh" }
-	exit 1
-}
-
-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"
+if [ "$command" ]; then
+  exec chroot "$dest" su $user -c "$command"
+elif [ "$#" -gt 0 ]; then
+  exec chroot "$dest" su $user -c "$*"
+else
+  exec chroot "$dest" login -f $user
+fi