sshpf Files

# Change log
#
# 5.47
# - The server dest connections list file (sshpf.py.avail_connections.txt) is
#   now updated in one cmd transaction to speed up it's creation.
#
# 5.46
# - We now wait a maximum of twice as long (previously it was always twice as 
#   long, up to a max value) for the next connection update. 
#   We randomise this time period to spread out src client 
#   attempts to gain server lock between self._keepAliveSeconds and 
#   SrcClient.MAX_UPDATE_CONNECTIONS_SECONDS which spreads out the 
#   contentions.
#
# 5.45
# - Fix allocation of server ports. Previously if a dest client was not 
#   connected the port could be reallocated to another dest client as it
#   connected. Ports should be reserved so that if a dest client connects
#   again it uses the same server port as last time it connected.
# - Added check for duplicate ssh server ports. 
#
# 5.44
# - The src client checked for conneciton updates (new destination clients 
#   connected to the ssh server every 5 seconds. In order to do this server lock 
#   is required. With many source clients connected it could take a long time to 
#   obtain server lock and then lock attempt timeouts which made connectivity 
#   unstable. 
#   Therfore after the keepalive period has elapsed after initial connection to 
#   the server a check is made for connected dest clients. The next time around 
#   2* the keeplaice period must elapse before a check is made for connected 
#   dest clients. This check period keeps doubling up to a max of 3600 seconds.
#   This reduces significantley the requirement for the src client to obtain 
#   server lock and so should stop the above condition occuring but also has the
#   side effect that it could take up to 1 hour for the src client to be aware 
#   of a newly connected dest client although the user could always disconnect 
#   the src client and reconnect to the server to obtain an up to date list 
#   of available dest client connections.
#
# 5.43
# - Obtain and release server access lock when the ClientMgmt class deletes the 
#   sshpf.py.avail_connections.txt file. This will hopefully overcome situations
#   where more dest clients are connected than are listed in this file.
#
# 5.4
# - Syslog messages now have the following components
#       0 = time/date stamp
#       1 = hostname
#       2 = main python file name
#       3 = PID
#       4 = username under which the program is being executed
#       5 = The syslog message
# - syslog messages can be disabled if the 'uio_syslog_off' file exists in
#   the users home directory.
#
# 5.3
# - Added ability to auto generate private/public ssh keys.
#
# 5.2
# - authorized keys backup files now roll around after 10 files have been
#   created.
#
# 5.1
# - Src client now attempts to reconnect to the server if the ssh server cannot
#   be reached.
# - Changed autostart startup times from 30/50 seconds to 10/15 seconds to allow
#   quicker activation of sshpf services after Linux PC startup.
#
# 5.0
# - Added check for -u command line argument in list of argsa that may be 
#   present on a single run.
# - Install now installs sshpf.py into the python site packages directory
#   so that import sshpf can be used if required to access module functionality 
#   from other programs.
# - In quiet mode no text is output to stdout, previously the version was shown
#   on stdout.
#
# 4.91
# - Rationalise the use of absoloute server paths.
# - When autostarting clients don't allow auto start if a src client appears to
#   be running.
# 
# 4.9
# - Set src client reconnect delay failed because server path was not included 
#   in filename. Fixed
#
# 4.8
# - Removed the option to set the reconnect period on the command line.
# - Added the ability to et the reconnect time when forcing a dest client and 
#   src client to disconnect from the ssh server. 
# 
# 4.7
# - SERVER_PORT_SCRIPT_FILENAME_V1 and TCP_CONNECT_SCRIPT_FILENAME_V1 python 
#   scripts created on server were not being updated with the port number
#   and so giving incorrect results. Replaced with 
#   SERVER_PORT_SCRIPT_FILENAME_V2 and TCP_CONNECT_SCRIPT_FILENAME_V2 
#   which take the port number as a command line argument. 
#
# 4.6
# - Shutdown dest client during initialisation if requested to do so.
#
# 4.5
# - Use src and dest, rather than source and destination when identifying 
#   clients. Previously there was a mix of terms src and source , dest
#   and destination
#
# 4.4
# - When disabling auto start ask the user if they wish to proceed as previously
#   autostart was disabled if the menu option was selected.
#
# 4.3
# - On the dest client before setting up forwarding we attempt to build a 
#   connection to the server port as the ssh server may not have released
#   the port from a previous port forwarding attempt and the action of
#   attempting to connect to it causes the ssh server to release the port.
#
# 4.2
# - Mgmt menu now prints a blank line to make it eaiser to see the results of
#   the previous command.
# - When displaying connection table do not limit table width to 80 characters.
#
# 4.1
# - getSrcClientForwardingConnections(), updated to check that the available
#   connections file exists.
#
# 4.0
# - Major re-arch to fix reliability and usability issues.
#
# 3.93
# - Randomize poll period between attempts to obtain server lock.
#
# 3.91
# - Provide implementation of disconnectAllSrcClients().
# - Disable port remap option when disconnecting all dest clients as it breaks
#   all dest client connections.
#
# 3.9
# - Added command line arguments to disaconnect src clients and view how many 
#  src clients are connected.
#
# 3.8
# - Get a list of the files created by dest clients from the server under server 
#   lock. This fixes a problem where the connected client list (when using the 
#   --srccc command line argument) did not return a consitent list of connected 
#   dest clients. 
#
# 3.7
# - Changed the way src client listen ports are defines. We now attempt to make
#   them the same as the ssh server listen port. This fixes the problem when 
#   disconnecting clients and remapping port usage.
#
# 3.6
# - Fixed server access lock as server access was broken and causing atomicity 
#   problems when clients were accessing the ssh server (E.G when creating *.py
#   files on the ssh server)
# - EnsureConfigDirExists now has server access control.
# - --enable_autostart was creating files named 1 in config dir. Fixing stderr 
#   redirection fixed this.
# - When --disable_autostart is used do not prompt for host and username.
# - If clearing the src or dest lock files then do this befgore running any 
#   other actions requested on the command line.
# - --disable_autostart command line option does not shutdown src/dest client
#   correctly. Fixed
# - Add code to shutdown dest clients if user presses control C after dest 
#   client has been started from the command line.
# - Add src client shutdown server lock remove code to src client.
# - Return server lock timeout to 60 seconds.
#
# 3.5
# - Added a delay to the auto start script as the ethernet interface may not be
#   up as the computer starts.
# - Change the disconnect dest client mechanism as the atomicity issues occured
#   with the previous mechanism. Now we create a file, the dest client sees it
#   deletes it and disconnects.
# - Add a command line option to disconnect all connected dest clients.
#   
# 3.4
# - When using the --srccc to get a list of the connected dest clients
#   display the time that each dest client connection has been connected.
# - When configuring dest client check for duplicate computer/service port pairs
#   Need to build connection with ssh server for this.
# - Add cmd line option to uninstall sshpf from a Linux PC.
# - Provide command line option to disbale ssh server auto login. This allows 
#   the user to remove an entry from the ~/.ssh/authorized_keys file. Backups of
#   all previous changes to this file are kept as ~/.ssh/authorized_keys.1, 
#   ~/.ssh/authorized_keys.2 etc.
#
# 3.3
# - Added command line option to disonnect a single dest client.
# - Added --install option to install itself onto Linux platforms.
#
# 3.2
# - -srccc command line argument did not work. Fixed.
#
# 3.1
#
# - Dest client change.When the dest client connects to the ssh server it
#   creates the <computer name>_<service name>_<service port>.dest_connected.0 
#   file. With each keepalive attempt (every 5 sefconds) this suffix number
#   increments. If this file is removed while the dest client is connected then 
#   the dest client will disconnect and reconnect to the ssh server.
#  
# - Src client change. Ensure the entries in the
#   local sshpf.py.saved_connections.txt allways match those detailed in the
#   remote (ssh server) .sshpf.py.avail_connections.txt file.
#
# - Src client change.
#   When the src client connects to the ssh server and when it updates the 
#   local ssh connection list, if it finds a computer name in 
#   its local .sshpf.py.saved_connections.txt file that is not in the server 
#   .sshpf.py.avail_connections.txt file then it will be removed from the local
#   file.
#
# - Add cmd line option to delete a dest client connection from the ssh server.
#   - ssh to server
#   - Get dest client list from the server
#   - Show this list to the user
#   - User enters index of the dest client they wish to delete 
#   - Prompt user that the dest client will be disconnected and as if it is ok to proceed
#     - Check (poll every second) if the dest_connected file is incrementing. If it is
#     - Delete the dest_conected file
#   - Delete the entry from the server ~/.sshpf.py.avail_connections.txt file.

# - Use the incrementing dest_connected file to determine which dest 
#   clients are connected rather than checking for the server ports that are in use.

# - GetDestConnectedFilename now identifies the connection by the computer name 
#   and local port only as the service name is not relevant to the service
#   identity and is only a label for the user.

# - getUserHome() removed and all reference to local config files now use the 
#   Client.LOCAL_CONFIG_DIR attribute.
#
# 3.0
# - Updated the command line help text to make it cleared what each argument does.
# - Warn useer of command line iotions that should not be used at the same time.
# - Change --user argument to --username
# - If the --host or --usernamne arguments are not supplied then prompt the user
#   to enter them. This should improve usability. 
#
# 2.9
# When using autostart ensure that the startup script users the correct hostname.
#
# 2.8
# When the --noautostart option is used check if src or dest clients are running
# and give the user the option to stop them running.
#
# 2.7
# Added a --srccc command line option to show available dest client connections.
# This has to connect to the ssh server an so is a bit slow. Therefore the 
# previous command line option can still be used (--srcc) to quickly read a 
# local (to the src client) list of all the possible dest client
# connections.
#
# 2.6
# When the --srcc command line argument ius used we now show a table of 
# connections that is easier to read.
#
# 2.5
# - Remove the startup delay option when the --autostart command line option is
#   used.
#
# 2.4
# - Fix for the previous change to ensure all previous sshpf threads were
#   terminated correctly.
#
# 2.3
# - Require the user to enter the --user command line argument to define thre ssh
#   username.
# - Remove the command line password argument as autologin must be configured. 
# - Ensure all sshpf processes are stopped before being restarted when using 
#   the --autostart argument.
#
# 2.2
# Changed the way server ports are allocated by the dest and src clients.
# We now search the saved configuration files on the ssh server (dest client)
# or src client machine for the next available port.
# Add a chedck for an unknown username and instruct user to user the --user 
# command line argument if no username can be determined.
#
# 2.1
# dest client forwarded port start ports listening on the ssh server. These 
# are controlled by the ssh server and do not get disocnnected (stay listening 
# ports) when the ssh connectin drops. Therefore after an ssh connection is 
# dropped we no make an attempt to connect to the port on the server that was
# previously used. This attempt causes the ssh server to release the socket 
# bind so that the subsequent attempt to setup port forwarding succeeds. 
#
# 2.0
# Attempt to cleanup dest client port forwarded connections in an attempt to
# ensure ports are not left hanging around at the server.
#
# 1.9
# Attempt to close port forwarding sessions when shutting down the dest client.
#
# 1.8
# Add dest client ID to the messages generated so that problems can be traced
# using syslog data.
#
# 1.7
# Change startup delay default presented to user from 30 to 60 seconds.
# Change order of startup configuration optiions.
#
# 1.6
# Added ability to configured the autostartup delay. When configuring sshpf to
# run when the computer startsup a delay may be performed to allow the network
# interface to come up. This was previously fixed at 10 seconds but may be 
# variable now as different computers may take different time periods before 
# the network interface is available.
# Also when configuring autostart allow the user to startup the sshpf clients 
# imediatley if required, rather than requiring a reboot.
#
# 1.5
# Added GNU GPL banner to this src file.
#
# 1.4
# The src clioent local lock file was expected to be in the user dir. This
# is incorrect, it should be in the user home folder. Fixed.
#
# 1.3
# Added ability to reconnect to ssh server even if initial connect fails.
# When a src or dest client thread raises an error and debug mode is off
# a stack trace is not longer printed, just an error message containing the
# exception text. If debug mode is not set off then a stack trace will
# be raised.
#
# 1.2
# Added the ability to remove the above startup configuration. 
#
# 1.1
# Added ability to configure auto start on linux systems.
#
# 1.0
# Initial release
#

Initial release