Update enter_chroot.sh to exit with error messages when mount/unmount fails.

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.
@@ skipping 60 matching lines @@
 
 function setup_env {
   (
     flock 200
     echo $$ >> "$LOCKFILE"
 
     echo "Mounting chroot environment."
 
     # Mount only if not already mounted
     MOUNTED_PATH="$(readlink -f "$FLAGS_chroot/proc")"
-    if [ -z "$(mount | grep -F "on $MOUNTED_PATH")" ]
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
-      sudo mount none -t proc "$MOUNTED_PATH"
+      sudo mount none -t proc "$MOUNTED_PATH" || \
+          die "Could not mount $MOUNTED_PATH"
     fi
 
     MOUNTED_PATH="$(readlink -f "$FLAGS_chroot/dev/pts")"
-    if [ -z "$(mount | grep -F "on $MOUNTED_PATH")" ]
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
-      sudo mount none -t devpts "$MOUNTED_PATH"
+      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 $MOUNTED_PATH")" ]
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
-      sudo mount --bind "$FLAGS_trunk" "$MOUNTED_PATH"
+      sudo mount --bind "$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 $MOUNTED_PATH")" ]
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
       ! CHROME_ROOT="$(readlink -f "$FLAGS_chrome_root")"
       if [ -z "$CHROME_ROOT" ]; then
         ! CHROME_ROOT="$(cat "${FLAGS_chroot}${CHROME_ROOT_CONFIG}" \
           2>/dev/null)"
       fi
       if [[ ( -z "$CHROME_ROOT" ) || ( ! -d "${CHROME_ROOT}/src" ) ]]; then
         echo "Not mounting chrome source"
         sudo rm -f "${FLAGS_chroot}${CHROME_ROOT_CONFIG}"
       else
         echo "Mounting chrome source at: $INNER_CHROME_ROOT"
         echo "$CHROME_ROOT" | \
           sudo dd of="${FLAGS_chroot}${CHROME_ROOT_CONFIG}"
         mkdir -p "$MOUNTED_PATH"
-        sudo mount --bind "$CHROME_ROOT" "$MOUNTED_PATH"
+        sudo mount --bind "$CHROME_ROOT" "$MOUNTED_PATH" || \
+          die "Could not mount $MOUNTED_PATH"
       fi
     fi
 
     MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}${INNER_DEPOT_TOOLS_ROOT}")"
-    if [ -z "$(mount | grep -F "on $MOUNTED_PATH")" ]
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
       if [ $(which gclient 2>/dev/null) ]; then
         echo "Mounting depot_tools"
         DEPOT_TOOLS=$(dirname $(which gclient) )
         mkdir -p "$MOUNTED_PATH"
         if ! sudo mount --bind "$DEPOT_TOOLS" "$MOUNTED_PATH"; then
           echo "depot_tools failed to mount; perhaps it's on NFS?"
           echo "This may impact chromium build."
         fi
       fi
     fi
-  ) 200>>"$LOCKFILE"
+  ) 200>>"$LOCKFILE" || die "setup_env failed"
 }
 
 function teardown_env {
   # Only teardown if we're the last enter_chroot to die
-
-  # We should not return with an error if cleanup has an error.  Cleanup is
-  # best effort only.
-  set +e
-
   (
     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 [ -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."
-      mount | grep "on $(readlink -f "$FLAGS_chroot")" | awk '{print $3}' \
-        | xargs -r -L1 sudo umount
+      for i in $(mount | grep -F "on $MOUNTED_PATH/" | awk '{print $3}'); do
+        sudo umount "$i" || die "Failed to umount $i"
+      done
     fi
-  ) 200>>"$LOCKFILE"
+  ) 200>>"$LOCKFILE" || die "teardown_env failed"
 }
 
 if [ $FLAGS_mount -eq $FLAGS_TRUE ]
 then
   setup_env
   echo "Make sure you run"
   echo "    $0 --unmount"
   echo "before deleting $FLAGS_chroot"
   echo "or you'll end up deleting $FLAGS_trunk too!"
   exit 0
@@ skipping 39 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