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 82bd39b1653d5da470ae551754d131816ffe055b..a1143f11806a395c2803cf100b5bfb402d071d4c 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")"

[dgarrett, 2011/02/11 21:07:50]

Can't this line be redone as:

local mounted_path="$(readlink -f ${FLAGS_chroot}/${target})"

???

[rochberg, 2011/02/11 22:28:56]

The extra level of quoting is necessary if FLAGS_chroot has a space in it.   Did
I mention I hate the shell?

[dgarrett, 2011/02/12 00:39:45]

I think what happens to the quotes inside the $() confused me. You're right.

+
+  if [ -z "$(mount | grep -F "on $mounted_path ")" ]; then

[dgarrett, 2011/02/11 21:07:50]

I believe we are supposed to use ${mounted_path} instead of $mounted_path.

[rochberg, 2011/02/11 22:28:56]

We are.  Done.

+    # 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 "$FLAGS_chrome_root")"
@@ -347,13 +337,7 @@ CHROMEOS_VERSION_TRACK=$CHROMEOS_VERSION_TRACK CHROMEOS_VERSION_AUSERVER=$CHROME
 
 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 $MOUNTED_PATH"
-  fi
+  ensure_mounted "${HOME}/.subversion" "--bind" "/home/${USER}/.subversion"
 fi
 
 # Configure committer username and email in chroot .gitconfig