Refuse to delete chroots which are in use

It turns out that `manage-baserock rm` can delete data from filesystems
that are mounted in a chroot directory. This is most likely to happen if
the chroot is active (and schroot created the mounts), so let's check
that there are no active sessions before deleting.

You now get a message like this if you try to remove a chroot with
active sessions:

    I found the following active sessions for chroot '15.19':

    session:baserock-15.19-4ef616d2-fdbf-4796-bcee-7132b989a2f8
    session:baserock-15.19-e0f00498-190a-44be-9d29-cce057cbb259

    You might lose data in mounted filesystems if I were to
    recursively delete path /opt/baserock/chroots/15.19.

    If you think these sessions are stale, you can run the
    following command to end ALL schroot sessions:

        schroot --end-session --all-sessions

I found that on my laptop there were a lot of stale sessions, probably
from when my computer had crashed while an 'schroot' session was open
so the session didn't get automatically ended. Stale sessions now will
prevent the user from being able to use `manage-baserock rm` so we need
to tell them about them.

Change-Id: I90aa19717d8e7007fb6aced9a8e9422967ddc64f

1 files changed, 22 insertions, 0 deletions

diff --git a/manage-baserock b/manage-baserock
index f7cc328..f1d7611 100755
--- a/manage-baserock
+++ b/manage-baserock
@@ -39,6 +39,11 @@ list_baserocks () {
     (cd "${BASEROCK_BASE}" && ls -d */baserock) 2>/dev/null | sed -e's@/baserock$@@'
 }
 
+list_sessions_for_system () {
+    local system="$1"
+    schroot --list --all-sessions | grep "^session:baserock-${system}"
+}
+
 case "${ACTION}" in
     list)
         for SYSTEM in $(list_baserocks); do
@@ -140,6 +145,23 @@ EOF
             echo "Sorry, $SYSTEM does not exist or is not a baserock chroot"
             exit 1
         fi
+
+        sessions="$(list_sessions_for_system $SYSTEM)"
+        if ! test -z $sessions; then
+            echo "I found the following active sessions for chroot '$SYSTEM':"
+            echo
+            echo "$sessions"
+            echo
+            echo "You might lose data in mounted filesystems if I were to"
+            echo "recursively delete path ${BASEROCK_BASE}/${SYSTEM}."
+            echo
+            echo "If you think these sessions are stale, you can run the "
+            echo "following command to end ALL schroot sessions:"
+            echo
+            echo "    schroot --end-session --all-sessions"
+            exit 1
+        fi
+
         rm -rf "${BASEROCK_BASE}/${SYSTEM}"
         br-ct-sync-chroots
         ;;