enter_chroot: when preparing chroot, mount devpts filesystem as well

enter_chroot.sh

 #!/bin/bash
 
 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to enter the chroot environment
 
 # Load common constants.  This should be the first executable line.
 # The path to common.sh should be relative to your script's location.
@@ skipping 86 matching lines @@
           die "Could not mount $MOUNTED_PATH"
     fi
 
     MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}/dev")"
     if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
       sudo mount --bind /dev "$MOUNTED_PATH" || \
           die "Could not mount $MOUNTED_PATH"
     fi
 
+    MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}/dev/pts")"
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
+    then
+      sudo mount none -t devpts "$MOUNTED_PATH" || \
+          die "Could not mount $MOUNTED_PATH"
+    fi
+
     MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}$CHROOT_TRUNK_DIR")"
     if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
       sudo mount --bind "$FLAGS_trunk" "$MOUNTED_PATH" || \
           die "Could not mount $MOUNTED_PATH"
     fi
 
     MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}${INNER_CHROME_ROOT}")"
     if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
@@ skipping 82 matching lines @@
       gconftool-2 -s --type=boolean ${AUTOMOUNT_PREF} ${SAVED_PREF} || \
         echo "could not re-set your automount preference."
     fi
 
     if [ -s "$LOCKFILE" ]; then
       echo "At least one other pid is running in the chroot, so not"
       echo "tearing down env."
     else
       MOUNTED_PATH=$(readlink -f "$FLAGS_chroot")
       echo "Unmounting chroot environment."
-      for i in $(mount | grep -F "on $MOUNTED_PATH/" | awk '{print $3}'); do
+      # sort the list of mounts in reverse order, to ensure umount of
+      # cascading mounts in proper order
+      for i in \
+        $(mount | grep -F "on $MOUNTED_PATH/" | sort -r | awk '{print $3}'); do
         safe_umount "$i"
       done
     fi
   ) 200>>"$LOCKFILE" || die "teardown_env failed"
 }
 
 if [ $FLAGS_mount -eq $FLAGS_TRUE ]
 then
   setup_env
   echo "Make sure you run"
@@ skipping 32 matching lines @@
 
 # Run command or interactive shell.  Also include the non-chrooted path to
 # the source trunk for scripts that may need to print it (e.g.
 # build_image.sh).
 sudo chroot "$FLAGS_chroot" sudo -i -u $USER $CHROOT_PASSTHRU \
   EXTERNAL_TRUNK_PATH="${FLAGS_trunk}" LANG=C "$@"
 
 # Remove trap and explicitly unmount
 trap - EXIT
 teardown_env