Support systemd socket activation

Check if systemd passed us a socket when starting obmc-console before
creating the socket ourselves. This will support use cases where we
don't need obmc-console until a SoL is activated by the user.

Tested: Verified that existing unit file installation is unchanged -
statically enabled obmc-console@.service instances will be started.

Then disabled obmc-console@ttyS2.service and enabled
obmc-console@ttyS2.socket (with a drop-in change to override
ListenStream to "obmc-console") and verifed that activating Redfish and
SSH SoL would start obmc-console@ttyS2.service and console redirection
worked.

Change-Id: I42e96af46a5893145abf27761e97fd4f1b73719d
Signed-off-by: Jonathan Doman <jonathan.doman@intel.com>
4 files changed
tree: 0c3c8459903b0151d40a6ea4b9bfc32198fce91e
  1. conf/
  2. test/
  3. .gitignore
  4. .travis.yml
  5. bootstrap.sh
  6. config.c
  7. configure.ac
  8. console-client.c
  9. console-server.c
  10. console-server.h
  11. console-socket.c
  12. LICENSE
  13. log-handler.c
  14. Makefile.am
  15. OWNERS
  16. README.md
  17. ringbuffer.c
  18. socket-handler.c
  19. tty-handler.c
  20. util.c
README.md

To Build

Note: In addition to a toolchain and autoconf tools, this requires autotools-archive to be installed.

To build this project, run the following shell commands:

./bootstrap.sh
./configure ${CONFIGURE_FLAGS}
make

To fully clean the repository, run:

./bootstrap.sh clean

To Run Server

Running the server requires a serial port (e.g. /dev/ttyS0):

touch obmc-console.conf
./obmc-console-server --config obmc-console.conf ttyS0

To Connect Client

To connect to the server, simply run the client:

./obmc-console-client

To disconnect the client, use the standard ~. combination.

Underlying design

This shows how the host UART connection is abstracted within the BMC as a Unix domain socket.

               +--------------------------------------------------------------------------------------------+
               |                                                                                            |
               |       obmc-console-client      unix domain socket         obmc-console-server              |
               |                                                                                            |
               |     +---------------------+                           +------------------------+           |
               |     | client.2200.conf    |  +---------------------+  | server.ttyVUART0.conf  |           |
           +---+--+  +---------------------+  |                     |  +------------------------+  +--------+-------+
Network    | 2200 +-->                     +->+ @obmc-console.host0 +<-+                        <--+ /dev/ttyVUART0 |   UARTs
           +---+--+  | socket-id = "host0" |  |                     |  | socket-id = "host0"    |  +--------+-------+
               |     |                     |  +---------------------+  |                        |           |
               |     +---------------------+                           +------------------------+           |
               |                                                                                            |
               |                                                                                            |
               |                                                                                            |
               +--------------------------------------------------------------------------------------------+

This supports multiple independent consoles. The socket-id is a unique portion for the unix domain socket created by the obmc-console-server instance. The server needs to know this because it needs to know what to name the pipe; the client needs to know it as it needs to form the abstract socket name to which to connect.