remove mounts automatically

Also combined all these little mount and cleanup helpers into one
`cleanup` script with flags.

README.md

@@ -71,26 +71,18 @@ or
 Destroy Environment
 -------------------
 
-Because chroot environments require multiple mounted directories to work, you
-can't simply `rm -r` a chroot environment you created, or the repository as a
-whole, without unmounting the mount points first. If you have rebooted your
-machine since setting up the chroot environments, then you don't need to worry,
-part or all of the repository can be straight-forwardly deleted, but if you are
-working with the repository and want to delete something yourself, there are
-two helper scripts that can be used to clean up the mount points and chroot
-environments properly.
+The `create_environment` and `enter_environment` scripts try to clean up the
+mounts that they create, and the mounts will all disappear on reboot, but just
+in case they are still present, you can run `sudo ./cleanup` to delete the
+`test_environment` safely. If you want to delete both environments and
+`debootstrap` in one go, then `sudo ./cleanup everything` will safely unmount
+`test_environment` and then delete all three directories.
 
-First `sudo ./destroy_environment` will unmount and delete `test_environment`,
-allowing you to remove an old environment without immediately creating a new
-one. Anything else in the repository can be straight-forwardly deleted with
-`sudo rm -r`, so with this you can put the repository in whatever state you
-want it to be in.
-
-If you want to conveniently remove all debian/debootstrap tools added, then
-`sudo ./clean_everything` will run `destroy_environment`, and then delete
-`clean_environment` and `debootstrap` for you, as well as `debootstrap.tar.gz`
-if that got left behind by accident. Think of this as the 'distclean', for one
-specific distribution.
+`cleanup` has other options too. For example, if you want to chroot into the
+environment as root, you can manually add the mount points back using
+`sudo ./cleanup add_mounts`, and then chroot in yourself. There is also
+`sudo ./cleanup mounts` to remove the mounts manually without deleting
+`test_environment`.
 
 Reuse an Existing Environment
 -----------------------------

debian/cleanup

@@ -0,0 +1,90 @@
+#!/bin/sh
+
+if test `id -u` -ne 0
+then
+    echo "$0 must be run as root."
+    return
+fi
+
+FRESH=clean_environment
+ROOT=test_environment
+
+add_mount() {
+    if mountpoint "$ROOT$1" > /dev/null
+    then
+        echo "$ROOT$1 already mounted."
+    else
+        echo "Mounting $1 to $ROOT$1"
+        mkdir -p "$ROOT$1"
+        mount -o bind "$1" "$ROOT$1"
+    fi
+}
+
+remove_mount() {
+    if mountpoint "$ROOT$1" > /dev/null
+    then
+        echo "Unmounting $ROOT$1"
+        umount "$ROOT$1"
+    fi
+}
+
+add_mounts() {
+    add_mount /proc
+    add_mount /sys
+    add_mount /dev
+    add_mount /dev/pts
+}
+
+remove_mounts() {
+    remove_mount /dev/pts
+    remove_mount /dev
+    remove_mount /sys
+    remove_mount /proc
+}
+
+remove_environment() {
+    if test -d "$ROOT"
+    then
+        # Call this script that automatically unmounts the mount points too.
+        remove_mounts
+        echo "Removing $ROOT"
+        rm -r "$ROOT"
+    else
+        echo "No environment found at $ROOT. Doing nothing."
+    fi
+}
+
+remove_everything() {
+    if test -d "$ROOT"
+    then
+        # Call this script that automatically unmounts the mount points too.
+        remove_environment
+    fi
+
+    if test -d "$FRESH"
+    then
+        echo "Removing $FRESH"
+        rm -r "$FRESH"
+    fi
+
+    if test -d debootstrap
+    then
+        echo "Removing debootstrap"
+        rm -r debootstrap
+    fi
+
+    if test -f debootstrap.tar.gz
+    then
+        echo "Removing debootstrap.tar.gz"
+        rm debootstrap.tar.gz
+    fi
+}
+
+case "$1" in
+    everything)  remove_everything ;;
+    mounts)      remove_mounts ;;
+    add_mounts)  add_mounts ;;
+    environment) remove_environment ;;
+    "")          remove_environment ;;
+esac
+

debian/cleanup_everything

@@ -1,32 +0,0 @@
-#!/bin/sh
-
-if test `id -u` -ne 0
-then
-    echo "$0 must be run as root."
-    return
-fi
-
-if test -d test_environment
-then
-    # Call this script that automatically unmounts the mount points too.
-    ./destroy_environment
-fi
-
-if test -d clean_environment
-then
-    echo "Removing clean_environment"
-    rm -r clean_environment
-fi
-
-if test -d debootstrap
-then
-    echo "Removing debootstrap"
-    rm -r debootstrap
-fi
-
-if test -f debootstrap.tar.gz
-then
-    echo "Removing debootstrap.tar.gz"
-    rm debootstrap.tar.gz
-fi
-

debian/create_environment

@@ -20,7 +20,7 @@ fi
 if test -e "$ROOT"
 then
     echo "Existing installation found at $ROOT, removing."
-    ./destroy_environment
+    ./cleanup
 fi
 
 echo "Copying $FRESH to $ROOT."
@@ -28,7 +28,7 @@ cp -r "$FRESH" "$ROOT"
 
 echo "Initializing $ROOT."
 
-./mountpoints
+./cleanup add_mounts
 
 # Don't bother creating a new tmpfs. We don't want to leak files in, and we
 # don't want to waste more RAM on a second tmpfs. The whole thing is
@@ -38,3 +38,5 @@ chmod 1777 "$ROOT/tmp"
 cp -r install_scripts "$ROOT/root"
 
 chroot "$ROOT" /root/install_scripts/user_setup "$@"
+
+./cleanup mounts

debian/destroy_environment

@@ -1,30 +0,0 @@
-#!/bin/sh
-
-if test `id -u` -ne 0
-then
-    echo "$0 must be run as root."
-    return
-fi
-
-ROOT=test_environment
-
-cleanup_mount() {
-    if mountpoint "$1" > /dev/null
-    then
-        echo "Unmounting $1"
-        umount "$1"
-    fi
-}
-
-if test -e "$ROOT"
-then
-    cleanup_mount "$ROOT/dev/pts"
-    cleanup_mount "$ROOT/dev"
-    cleanup_mount "$ROOT/sys"
-    cleanup_mount "$ROOT/proc"
-    echo "Removing $ROOT"
-    rm -r "$ROOT"
-else
-    echo "No environment found at $ROOT. Doing nothing."
-fi
-

debian/enter_environment

@@ -15,6 +15,8 @@ else
     ./create_environment
 fi
 
-./mountpoints
+./cleanup add_mounts
 
 chroot "$ROOT" sudo -iu user "$@"
+
+./cleanup mounts