disable automounting when inside the chroot

src/scripts/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.
 . "$(dirname "$0")/common.sh"
 
 # Script must be run outside the chroot and as a regular user.
 assert_outside_chroot
 assert_not_root_user
 
 # Define command line flags
 # See http://code.google.com/p/shflags/wiki/Documentation10x
 DEFINE_string chroot "$DEFAULT_CHROOT_DIR" \
   "The destination dir for the chroot environment." "d"
 DEFINE_string trunk "$GCLIENT_ROOT" \
   "The source trunk to bind mount within the chroot." "s"
 DEFINE_string build_number "" \
   "The build-bot build number (when called by buildbot only)." "b"
 DEFINE_string chrome_root "" \
   "The root of your chrome browser source. Should contain a 'src' subdir."
-DEFINE_string automount_dir "/media" \
-  "The directory in which your host OS creates mountpoints for external media."
 
 DEFINE_boolean official_build $FLAGS_FALSE \
   "Set CHROMEOS_OFFICIAL=1 for release builds."
 DEFINE_boolean mount $FLAGS_FALSE "Only set up mounts."
 DEFINE_boolean unmount $FLAGS_FALSE "Only tear down mounts."
 
 # More useful help
 FLAGS_HELP="USAGE: $0 [flags] [VAR=value] [-- \"command\"]
 
 One or more VAR=value pairs can be specified to export variables into
@@ skipping 22 matching lines @@
 
 # Only now can we die on error.  shflags functions leak non-zero error codes,
 # so will die prematurely if 'set -e' is specified before now.
 # TODO: replace shflags with something less error-prone, or contribute a fix.
 set -e
 
 INNER_CHROME_ROOT="/home/$USER/chrome_root"  # inside chroot
 CHROME_ROOT_CONFIG="/var/cache/chrome_root"  # inside chroot
 INNER_DEPOT_TOOLS_ROOT="/home/$USER/depot_tools"  # inside chroot
 FUSE_DEVICE="/dev/fuse"
+AUTOMOUNT_PREF="/apps/nautilus/preferences/media_automount"
+SAVED_AUTOMOUNT_PREF_FILE="/tmp/.automount_pref"
 
 sudo chmod 0777 "$FLAGS_chroot/var/lock"
 
 LOCKFILE="$FLAGS_chroot/var/lock/enter_chroot"
 
 function setup_env {
   (
     flock 200
     echo $$ >> "$LOCKFILE"
 
@@ skipping 14 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}${FLAGS_automount_dir}")"
-    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
-    then
-      sudo mount --bind "${FLAGS_automount_dir}" "$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 28 matching lines @@
         fi
       fi
     fi
 
     # Install fuse module.
     if [ -c "${FUSE_DEVICE}" ] ; then
       sudo modprobe fuse 2> /dev/null ||\
         echo "-- Note: modprobe fuse failed.  gmergefs will not work"
     fi
 
+    # Turn off automounting of external media when we enter the
+    # chroot; thus we don't have to worry about being able to unmount
+    # from inside.
+    if [ $(which gconftool-2 2>/dev/null) ]; then
+      gconftool-2 -g ${AUTOMOUNT_PREF} > \
+        "${FLAGS_chroot}${SAVED_AUTOMOUNT_PREF_FILE}"
+      if [ $(gconftool-2 -s --type=boolean ${AUTOMOUNT_PREF} false) ]; then
+        echo "-- Note: USB sticks may be automounted by your host OS."
+        echo "-- Note: If you plan to burn bootable media, you may need to"
+        echo "-- Note: unmount these devices manually, or run image_to_usb.sh"
+        echo "-- Note: outside the chroot."
+      fi
+    fi
+
   ) 200>>"$LOCKFILE" || die "setup_env failed"
 }
 
 function teardown_env {
   # Only teardown if we're the last enter_chroot to die
   (
     flock 200
 
     # check each pid in $LOCKFILE to see if it's died unexpectedly
     TMP_LOCKFILE="$LOCKFILE.tmp"
 
     echo -n > "$TMP_LOCKFILE"  # Erase/reset temp file
     cat "$LOCKFILE" | while read PID; do
       if [ "$PID" = "$$" ]; then
         # ourself, leave PROC_NAME empty
         PROC_NAME=""
       else
         PROC_NAME=$(ps --pid $PID -o comm=)
       fi
 
       if [ ! -z "$PROC_NAME" ]; then
         # All good, keep going
         echo "$PID" >> "$TMP_LOCKFILE"
       fi
     done
     # Remove any dups from lock file while installing new one
     sort -n "$TMP_LOCKFILE" | uniq > "$LOCKFILE"
 
+    if [ $(which gconftool-2 2>/dev/null) ]; then
+      SAVED_PREF=$(cat "${FLAGS_chroot}${SAVED_AUTOMOUNT_PREF_FILE}")
+      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 $3}'); do
         safe_umount "$i"
       done
     fi
@@ skipping 50 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