css-child-read-write.sh

#!/bin/bash
# This is a helper script which is called by container-storage-setup.sh (d-s-s).
# This script helps in providing synchronization primitives to d-s-s so that
# d-s-s can determine whether deferred deletion is supported by the underlying
# kernel or not.

# $1 is named FIFO pipe.
# This helper script will write to $1 to signal d-s-s that unshare has been completed successfully.

# $2 is another named FIFO pipe.
# This helper script will read from $2. The write for this pipe would come from d-s-s to indicate
# that helper script can terminate now.

# $3 is absolute path to a temp dir which child will bind mount. Parent will
# later try to remove this dir.

if ! mount -o bind $3 $3; then
   echo "stop" > $1
   exit 1
fi
echo "start" > $1
read -t 10 n <>$2