1 files changed, 78 insertions, 0 deletions
diff --git a/arch-chroot.in b/arch-chroot.in
new file mode 100644
index 0000000..a954953
--- /dev/null
+++ b/arch-chroot.in
@@ -0,0 +1,78 @@
+#!/bin/bash
+
+shopt -s extglob
+
+m4_include(common)
+
+usage() {
+  cat <<EOF
+usage: ${0##*/} chroot-dir [command]
+
+    -h                  Print this help message
+    -u <user>[:group]   Specify non-root user and optional group to use
+
+If 'command' is unspecified, ${0##*/} will launch /bin/bash.
+
+EOF
+}
+
+chroot_add_resolv_conf() {
+  local chrootdir=$1 resolv_conf=$1/etc/resolv.conf
+
+  # 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 $chrootdir/etc/resolv.conf ]]; then
+    # The chroot might not have a resolv.conf.
+    return 0
+  fi
+
+  chroot_add_mount /etc/resolv.conf "$resolv_conf" --bind
+}
+
+while getopts ':hu:' flag; do
+  case $flag in
+    h)
+      usage
+      exit 0
+      ;;
+    u)
+      userspec=$OPTARG
+      ;;
+    :)
+      die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
+      ;;
+    ?)
+      die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
+      ;;
+  esac
+done
+shift $(( OPTIND - 1 ))
+
+(( EUID == 0 )) || die 'This script must be run with root privileges'
+(( $# )) || die 'No chroot directory specified'
+chrootdir=$1
+shift
+
+[[ -d $chrootdir ]] || die "Can't create chroot on non-directory %s" "$chrootdir"
+
+chroot_setup "$chrootdir" || die "failed to setup chroot %s" "$chrootdir"
+chroot_add_resolv_conf "$chrootdir" || die "failed to setup resolv.conf"
+
+chroot_args=()
+[[ $userspec ]] && chroot_args+=(--userspec "$userspec")
+chroot_args+=("$chrootdir" "$@")
+
+SHELL=/bin/bash unshare --fork --pid chroot "${chroot_args[@]}"