replace arch-nspawn with chroot-run (nonsystemd compat)

based in artix/artools

Signed-off-by: David P <megver83@parabola.nu>

Previously, these changes were kept on a separate nonsystemd branch
for nonsystemd releases from v20180428 to v20190907.
The nonsystemd build seems to work well on systemd systems,
and it has no dependencies in [nonsystemd];
so there only needs to be one build in [libre].
This commit squashes the functional changes from the following commits
from the former nonsystemd branch:

  * 7a2c689f3808a8b970006f9e8f01e883490ea72b chroot-run: declare mount_args at the beginning of the scriptlibretools-v20190907-nonsystemd
  * 37de77a06e7917ff50dec6ca469b45700986c698 chroot-run: better unshare arguments handling	David P
  * 984c0b8e3c341b78ac689f0eeca1cf2460fc3336 chroot-run: use unshare	David P
  * a57dfdb1cb87f9959b1cc218036456be7c7fa81d initial systemd-nspawn replacement with chroot	David P

9 files changed, 161 insertions, 31 deletions

diff --git a/.gitignore b/.gitignore
index 1e92b82..0b61a93 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,4 +15,4 @@ rebuildpkgs
 zsh_completion
 find-libdeps
 crossrepomove
-arch-nspawn
+chroot-run
diff --git a/Makefile b/Makefile
index 2d29c83..46094e8 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@ BINPROGS = \
 	rebuildpkgs \
 	find-libdeps \
 	crossrepomove\
-	arch-nspawn \
+	chroot-run \
 	mkarchroot \
 	makechrootpkg
 
diff --git a/archbuild.in b/archbuild.in
index 1e5b582..4e2aa7c 100644
--- a/archbuild.in
+++ b/archbuild.in
@@ -67,7 +67,7 @@ if ${clean_first} || [[ ! -d "${chroots}/${repo}-${arch}" ]]; then
 		"${base_packages[@]}" || abort
 else
 	lock 9 "${chroots}/${repo}-${arch}/root.lock" "Locking clean chroot"
-	arch-nspawn \
+	chroot-run \
 		-C "@pkgdatadir@/pacman-${repo}.conf" \
 		-M "@pkgdatadir@/makepkg-${arch}.conf" \
 		"${chroots}/${repo}-${arch}/root" \
diff --git a/bash_completion.in b/bash_completion.in
index 9feef74..34a34af 100644
--- a/bash_completion.in
+++ b/bash_completion.in
@@ -68,7 +68,7 @@ _mkarchroot() {
 } &&
 complete -F _mkarchroot mkarchroot
 
-_arch-nspawn() {
+_chroot-run() {
   local cur
   COMPREPLY=()
   _get_comp_words_by_ref cur
@@ -85,5 +85,5 @@ _arch-nspawn() {
 
   true
 } &&
-complete -F _arch-nspawn arch-nspawn
+complete -F _chroot-run chroot-run
 # ex:et ts=2 sw=2 ft=sh
diff --git a/arch-nspawn.in b/chroot-run.in
index 96b3e38..4d832ec 100644
--- a/arch-nspawn.in
+++ b/chroot-run.in
@@ -12,32 +12,64 @@
 
 m4_include(lib/common.sh)
 m4_include(lib/archroot.sh)
+m4_include(lib/mount.sh)
+
+# $1: chroot
+kill_chroot_process(){
+    local prefix="$1" flink pid name
+    for root_dir in /proc/*/root; do
+        flink=$(readlink "$root_dir")
+        if [ "x$flink" != "x" ]; then
+            if [ "x${flink:0:${#prefix}}" = "x$prefix" ]; then
+                # this process is in the chroot...
+                pid=$(basename "$(dirname "$root_dir")")
+                name=$(ps -p "$pid" -o comm=)
+                msg2 "Killing chroot process: %s (%s)" "$name" "$pid"
+                kill -9 "$pid"
+            fi
+        fi
+    done
+    sleep 1
+}
 
-working_dir=''
+# umask might have been changed in /etc/profile
+# ensure that sane default is set again
+umask 0022
 
+working_dir=''
 files=()
 
+mount_args=("-B:/etc/hosts:/etc/hosts")
+unshare_args=("-Cfimu")
+
 usage() {
-	echo "Usage: ${0##*/} [options] working-dir [systemd-nspawn arguments]"
-	echo "A wrapper around systemd-nspawn.  Provides support for pacman."
+	echo "Usage: ${0##*/} [options] working-dir [chroot arguments]"
+	echo "A wrapper around chroot.  Provides support for pacman."
 	echo
 	echo ' options:'
 	echo '    -C <file>     Location of a pacman config file'
 	echo '    -M <file>     Location of a makepkg config file'
 	echo '    -c <dir>      Set pacman cache'
 	echo '    -f <file>     Copy file from the host to the chroot'
+	echo '                  This option may be given multiple times'
 	echo '    -s            Do not run setarch'
+	echo '    -b <args>     Bind mountargs'
+	echo "                  <args> format: 'mntarg:srcdir:destdir'"
+	echo '                  This option may be given multiple times'
+	echo '    -N            Disable networking'
 	echo '    -h            This message'
 	exit 1
 }
 
-while getopts 'hC:M:c:f:s' arg; do
+while getopts 'hC:M:c:f:sb:N' arg; do
 	case "$arg" in
 		C) pac_conf="$OPTARG" ;;
 		M) makepkg_conf="$OPTARG" ;;
 		c) cache_dir="$OPTARG" ;;
 		f) files+=("$OPTARG") ;;
 		s) nosetarch=1 ;;
+		b) mount_args+=("$OPTARG") ;;
+		N) unshare_args+=("-n") ;;
 		h|?) usage ;;
 		*) error "invalid argument '%s'" "$arg"; usage ;;
 	esac
@@ -66,16 +98,14 @@ host_mirror=$($pacconf_cmd --repo extra Server 2> /dev/null | head -1 | sed -r '
 
 # {{{ functions
 build_mount_args() {
-	declare -g mount_args=()
-
 	if [[ -n $host_mirror_path ]]; then
-		mount_args+=("--bind-ro=$host_mirror_path")
+		mount_args+=("-B:$host_mirror_path:$host_mirror_path")
 	fi
 
-	mount_args+=("--bind=${cache_dirs[0]}")
+	mount_args+=("-B:${cache_dirs[0]}:${cache_dirs[0]}")
 
 	for cache_dir in "${cache_dirs[@]:1}"; do
-		mount_args+=("--bind-ro=$cache_dir")
+		mount_args+=("-Br:$cache_dir:$cache_dir")
 	done
 }
 
@@ -94,6 +124,16 @@ copy_hostconf () {
 
 	sed -r "s|^#?\\s*CacheDir.+|CacheDir = ${cache_dirs[*]}|g" -i "$working_dir/etc/pacman.conf"
 }
+
+chroot_extra_mount() {
+	chroot_add_resolv_conf "${working_dir}"
+
+	for arg in "${mount_args[@]}"; do
+		local flag=${arg%%:*} dest=${arg##*:} src=${arg%:*}
+		src=${src#*:}
+		chroot_mount "${src}" "${working_dir}${dest}" "${flag}"
+	done
+}
 # }}}
 
 umask 0022
@@ -106,6 +146,8 @@ elif [[ $(cat "$working_dir/.arch-chroot") != "$CHROOT_VERSION" ]]; then
 fi
 
 build_mount_args
+chroot_api_mount "${working_dir}" || die "failed to setup API filesystems in chroot %s" "${working_dir}"
+chroot_extra_mount
 cache_dirs+=('/repo/')
 copy_hostconf
 
@@ -116,9 +158,14 @@ esac
 
 [[ -z $nosetarch ]] || unset CARCH
 
-exec ${CARCH:+setarch "$CARCH"} systemd-nspawn -q \
-	-D "$working_dir" \
-	-E "PATH=/usr/local/sbin:/usr/local/bin:/usr/bin" \
-	--register=no --keep-unit --as-pid2 \
-	"${mount_args[@]}" \
+${CARCH:+setarch "$CARCH"} unshare \
+	 "${unshare_args[@]}" \
+	--mount-proc \
+	--setgroups allow \
+	-- \
+	chroot \
+	"${working_dir}" \
 	"$@"
+ret=$?
+kill_chroot_process "${working_dir}"
+exit $ret
diff --git a/lib/mount.sh b/lib/mount.sh
new file mode 100644
index 0000000..2705717
--- /dev/null
+++ b/lib/mount.sh
@@ -0,0 +1,84 @@
+#!/hint/bash
+
+#{{{ mount
+
+ignore_error() {
+    "$@" 2>/dev/null
+    return 0
+}
+
+trap_setup(){
+    [[ $(trap -p EXIT) ]] && die 'Error! Attempting to overwrite existing EXIT trap'
+    trap "$1" EXIT
+}
+
+chroot_mount() {
+#     msg2 "mount: [%s]" "$2"
+    mount "$@" && CHROOT_ACTIVE_MOUNTS=("$2" "${CHROOT_ACTIVE_MOUNTS[@]}")
+}
+
+chroot_add_resolv_conf() {
+    local chrootdir=$1 resolv_conf=$1/etc/resolv.conf
+
+    [[ -e /etc/resolv.conf ]] || return 0
+
+    # Handle resolv.conf as a symlink to somewhere else.
+    if [[ -L $chrootdir/etc/resolv.conf ]]; then
+        # readlink(1) should always give us *something* since we know at this point
+        # it's a symlink. For simplicity, ignore the case of nested symlinks.
+        resolv_conf=$(readlink "$chrootdir/etc/resolv.conf")
+        if [[ $resolv_conf = /* ]]; then
+            resolv_conf=$chrootdir$resolv_conf
+        else
+            resolv_conf=$chrootdir/etc/$resolv_conf
+        fi
+
+        # ensure file exists to bind mount over
+        if [[ ! -f $resolv_conf ]]; then
+            install -Dm644 /dev/null "$resolv_conf" || return 1
+        fi
+    elif [[ ! -e $chrootdir/etc/resolv.conf ]]; then
+        # The chroot might not have a resolv.conf.
+        return 0
+    fi
+
+    chroot_mount /etc/resolv.conf "$resolv_conf" --bind
+}
+
+chroot_mount_conditional() {
+    local cond=$1; shift
+    if eval "$cond"; then
+        chroot_mount "$@"
+    fi
+}
+
+chroot_setup(){
+    local mnt="$1" os="$2" args='-t tmpfs -o nosuid,nodev,mode=0755'
+    $os && args='--bind'
+    chroot_mount_conditional "! mountpoint -q '$mnt'" "$mnt" "$mnt" --bind &&
+    chroot_mount proc "$mnt/proc" -t proc -o nosuid,noexec,nodev &&
+    chroot_mount sys "$mnt/sys" -t sysfs -o nosuid,noexec,nodev,ro &&
+    ignore_error chroot_mount_conditional "[[ -d '$mnt/sys/firmware/efi/efivars' ]]" \
+        efivarfs "$mnt/sys/firmware/efi/efivars" -t efivarfs -o nosuid,noexec,nodev &&
+    chroot_mount udev "$mnt/dev" -t devtmpfs -o mode=0755,nosuid &&
+    chroot_mount devpts "$mnt/dev/pts" -t devpts -o mode=0620,gid=5,nosuid,noexec &&
+    chroot_mount shm "$mnt/dev/shm" -t tmpfs -o mode=1777,nosuid,nodev &&
+    chroot_mount /run "$mnt/run" ${args} &&
+    chroot_mount tmp "$mnt/tmp" -t tmpfs -o mode=1777,strictatime,nodev,nosuid
+}
+
+chroot_api_mount() {
+    CHROOT_ACTIVE_MOUNTS=()
+    trap_setup chroot_api_umount
+    chroot_setup "$1" false
+}
+
+chroot_api_umount() {
+    if (( ${#CHROOT_ACTIVE_MOUNTS[@]} )); then
+#         msg2 "umount: [%s]" "${CHROOT_ACTIVE_MOUNTS[@]}"
+        umount "${CHROOT_ACTIVE_MOUNTS[@]}"
+    fi
+    unset CHROOT_ACTIVE_MOUNTS
+}
+
+#}}}
diff --git a/makechrootpkg.in b/makechrootpkg.in
index 492991e..cd58fb1 100644
--- a/makechrootpkg.in
+++ b/makechrootpkg.in
@@ -159,7 +159,7 @@ install_packages() {
 	pkgnames=("${install_pkgs[@]##*/}")
 
 	cp -- "${install_pkgs[@]}" "$copydir/root/"
-	arch-nspawn "$copydir" "${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
+	chroot-run "$copydir" "${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
 		pacman -U --noconfirm -- "${pkgnames[@]/#//root/}"
 	ret=$?
 	rm -- "${pkgnames[@]/#/$copydir/root/}"
@@ -435,8 +435,8 @@ main() {
 	while getopts 'hcur:I:l:nTD:d:U:' arg; do
 		case "$arg" in
 			c) clean_first=true ;;
-			D) bindmounts_ro+=("--bind-ro=$OPTARG") ;;
-			d) bindmounts_rw+=("--bind=$OPTARG") ;;
+			D) bindmounts_ro+=(-b "-Br:$OPTARG:$OPTARG") ;;
+			d) bindmounts_rw+=(-b "-B:$OPTARG:$OPTARG") ;;
 			u) update_first=true ;;
 			r) passeddir="$OPTARG" ;;
 			I) install_pkgs+=("$OPTARG") ;;
@@ -502,7 +502,7 @@ main() {
 		sync_chroot "$chrootdir/root" "$copydir" "$copy"
 	fi
 
-	$update_first && arch-nspawn "$copydir" \
+	$update_first && chroot-run "$copydir" \
 			"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
 			pacman -Syu --noconfirm
 
@@ -521,10 +521,9 @@ main() {
 	download_sources "$copydir" "$makepkg_user"
 
 	prepare_chroot "$copydir" "$USER_HOME" "$keepbuilddir" "$run_namcap"
-
-	if arch-nspawn "$copydir" \
-		--bind="$PWD:/startdir" \
-		--bind="$SRCDEST:/srcdest" \
+	if chroot-run "$copydir" \
+		-b "-B:$PWD:/startdir" \
+		-b "-B:$SRCDEST:/srcdest" \
 		"${bindmounts_ro[@]}" "${bindmounts_rw[@]}" \
 		/chrootbuild "${makepkg_args[@]}"
 	then
diff --git a/mkarchroot.in b/mkarchroot.in
index 5165960..0f6c408 100644
--- a/mkarchroot.in
+++ b/mkarchroot.in
@@ -90,9 +90,9 @@ printf '%s.UTF-8 UTF-8\n' en_US de_DE > "$working_dir/etc/locale.gen"
 echo 'LANG=en_US.UTF-8' > "$working_dir/etc/locale.conf"
 echo "$CHROOT_VERSION" > "$working_dir/.arch-chroot"
 
-systemd-machine-id-setup --root="$working_dir"
+dbus-uuidgen --ensure="$working_dir"/etc/machine-id
 
-exec "$(librelib chroot/arch-nspawn)" \
+exec "$(librelib chroot/chroot-run)" \
 	${nosetarch:+-s} \
 	${pac_conf:+-C "$pac_conf"} \
 	${makepkg_conf:+-M "$makepkg_conf"} \
diff --git a/zsh_completion.in b/zsh_completion.in
index 3bd4c4d..82bcced 100644
--- a/zsh_completion.in
+++ b/zsh_completion.in
@@ -1,4 +1,4 @@
-#compdef archbuild archco arch-nspawn archrelease archrm commitpkg finddeps makechrootpkg mkarchroot rebuildpkgs extrapkg=commitpkg corepkg=commitpkg testingpkg=commitpkg stagingpkg=commitpkg communitypkg=commitpkg community-testingpkg=commitpkg community-stagingpkg=commitpkg multilibpkg=commitpkg multilib-testingpkg=commitpkg extra-x86_64-build=archbuild testing-x86_64-build=archbuild staging-x86_64-build=archbuild multilib-build=archbuild multilib-testing-build=archbuild multilib-staging-build=archbuild kde-unstable-x86_64-build=archbuild gnome-unstable-x86_64-build=archbuild communityco=archco
+#compdef archbuild archco chroot-run archrelease archrm commitpkg finddeps makechrootpkg mkarchroot rebuildpkgs extrapkg=commitpkg corepkg=commitpkg testingpkg=commitpkg stagingpkg=commitpkg communitypkg=commitpkg community-testingpkg=commitpkg community-stagingpkg=commitpkg multilibpkg=commitpkg multilib-testingpkg=commitpkg extra-x86_64-build=archbuild testing-x86_64-build=archbuild staging-x86_64-build=archbuild multilib-build=archbuild multilib-testing-build=archbuild multilib-staging-build=archbuild kde-unstable-x86_64-build=archbuild gnome-unstable-x86_64-build=archbuild communityco=archco
 # License: Unspecified
 
 m4_include(lib/valid-tags.sh)
@@ -12,7 +12,7 @@ _archco_args=(
 	'*:packages:_devtools_completions_all_packages'
 )
 
-_arch_nspawn_args=(
+_chroot_run_args=(
 	'-C[Location of a pacman config file]:pacman_config:_files'
 	'-M[Location of a makepkg config file]:makepkg_config:_files'
 	'-c[Set pacman cache]:pacman_cache:_files -/'