Technical notes on version 1.7 07Dec01
                       08 December 2001
                        Kern Sibbald

General:
- This was a massive change to add use_count and locking
  to handling of jcr's, to make the Storage daemon
  accept any number of FD connections, and to add
  authentication between the SD and FD.
- With these changes, we should be able to do multiple
  simultaneous backups.

Changes submitted this submission:
- Moved more variables into the common section of the jcr.
- Made client_name a malloc()ed buffer.
- Made routines that search for a jcr increment the
  use count. This necessitated adding making a free_jcr()
  and a free_locked_jcr() routines so that a jcr could
  be freed up inside a loop walking down the jcr chain.
- Restructured free_jcr() so that it consists of common
  code (to remove the jcr from the chain and free 
  common buffers) located in lib/jcr.c. The jcr now
  also has a local free routine pointer. This pointer
  is set during new_jcr(), and called from the global
  free_jcr() routine.
- Modified bnet_thread_server() so that it is passed the
  work queue pointer. This allows it to be used for listening
  to multiple sockets.
- Major modifications to the storage daemon. It now listens
  on two sockets and accepts connections at any time. 
  Previously, it only accepted connections from the FD 
  when a job was started. The new scheme permits multiple
  jobs to be started, which then wait for a connection from
  the FD. When a connection is made, the proper jcr is found,
  the FD is authenticated (and vise-versa), and the waiting
  thread is awaken. The waiting job thread will wait 30
  minutes for a FD connection and then cancel the job.
- Moved JobFiles and JobBytes into the common section of 
  the jcr.
- Added an improved random key generator for the Storage
  daemon authentication key.