enter_chroot: Only mount SSH auth socket when we need to.

enter_chroot.sh

Index: enter_chroot.sh
diff --git a/enter_chroot.sh b/enter_chroot.sh
index 8e3d5898ece2f8ff028146784b5f1ad7b116d774..ac34ad961f583ffa9807c7462c421af638f0dfe5 100755
--- a/enter_chroot.sh
+++ b/enter_chroot.sh
@@ -73,7 +73,7 @@ Otherwise, provides an interactive shell.
 # Version of info from common.sh that only echos if --verbose is set.
 function debug {
   if [ $FLAGS_verbose -eq $FLAGS_TRUE ]; then
-    info "$1"
+    info "$*"
   fi
 }
 
@@ -132,6 +132,24 @@ sudo chmod 0777 "$FLAGS_chroot/var/lock"
 
 LOCKFILE="$FLAGS_chroot/var/lock/enter_chroot"
 
+
+function ensure_mounted {
+  # If necessary, mount $source in the host FS at $target inside the
+  # chroot directory with $mount_args.
+  local source="$1"
+  local mount_args="$2"
+  local target="$3"
+
+  local mounted_path="$(readlink -f "${FLAGS_chroot}/$target")"
+
+  if [ -z "$(mount | grep -F "on ${mounted_path} ")" ]; then
+    # NB:  mount_args deliberately left unquoted
+    debug mount ${mount_args} "${source}" "${mounted_path}"
+    sudo -- mount ${mount_args} "${source}" "${mounted_path}" || \
+      die "Could not mount ${source} on ${mounted_path}"
+  fi
+}
+
 function setup_env {
   # Validate sudo timestamp before entering the critical section so that we
   # don't stall for a password while we have the lockfile.
@@ -143,25 +161,11 @@ function setup_env {
     echo $$ >> "$LOCKFILE"
 
     debug "Mounting chroot environment."
-
-    # Mount only if not already mounted
-    MOUNTED_PATH="$(readlink -f "$FLAGS_chroot/proc")"
-    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]; then
-      sudo mount none -t proc "$MOUNTED_PATH" || \
-          die "Could not mount $MOUNTED_PATH"
-    fi
-
-    MOUNTED_PATH="$(readlink -f "$FLAGS_chroot/sys")"
-    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]; then
-      sudo mount none -t sysfs "$MOUNTED_PATH" || \
-          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 $MOUNTED_PATH"
-    fi
+    ensure_mounted none "-t proc" /proc
+    ensure_mounted none "-t sysfs" /sys
+    ensure_mounted /dev "--bind" /dev
+    ensure_mounted none "-t devpts" /dev/pts
+    ensure_mounted "${FLAGS_trunk}" "--bind" "${CHROOT_TRUNK_DIR}"
 
     if [ $FLAGS_ssh_agent -eq $FLAGS_TRUE ]; then
       TARGET_DIR="$(readlink -f "${FLAGS_chroot}/home/${USER}/.ssh")"
@@ -170,24 +174,10 @@ function setup_env {
         cp -r "${HOME}/.ssh/known_hosts" "${TARGET_DIR}"
         cp -r "${HOME}/.ssh/config" "${TARGET_DIR}"
         ASOCK="$(dirname "${SSH_AUTH_SOCK}")"
-        mkdir -p "${FLAGS_chroot}/${ASOCK}"
-        sudo mount --bind "${ASOCK}" "${FLAGS_chroot}/${ASOCK}" || \
-          die "Count not mount ${ASOCK}"
+        ensure_mounted "${ASOCK}" "--bind" "${ASOCK}"
       fi
     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 $MOUNTED_PATH ")" ]; then
       ! CHROME_ROOT="$(readlink -f "$FLAGS_chrome_root")"
@@ -378,14 +368,9 @@ CHROOT_PASSTHRU="${CHROOT_PASSTHRU} \
 CHROMEOS_VERSION_TRACK=$CHROMEOS_VERSION_TRACK CHROMEOS_VERSION_AUSERVER=$CHROMEOS_VERSION_AUSERVER CHROMEOS_VERSION_DEVSERVER=$CHROMEOS_VERSION_DEVSERVER"
 
 if [ -d "$HOME/.subversion" ]; then
-  # Bind mounting .subversion into chroot
-  debug "mounting ~/.subversion into chroot"
-  MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}/home/${USER}/.subversion")"
-  if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]; then
-    mkdir -p "$MOUNTED_PATH"
-    sudo mount --bind "$HOME/.subversion" "$MOUNTED_PATH" || \
-      die "Could not mount $MOUNTED_PATH"
-  fi
+  TARGET="/home/${USER}/.subversion"
+  mkdir -p "${FLAGS_chroot}${TARGET}"
+  ensure_mounted "${HOME}/.subversion" "--bind" "${TARGET}"
 fi
 
 # Configure committer username and email in chroot .gitconfig