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gerrit.openbmc.org / openbmc / obmc-console / ef07b7752773ed4d115e7641b1ffacece39a407d
commitef07b7752773ed4d115e7641b1ffacece39a407d[log] [tgz]
authorJeremy Kerr <jk@codeconstruct.com.au>Wed Sep 10 11:48:48 2025 +0800
committerEddie James <eajames@linux.ibm.com>Thu Sep 11 09:32:37 2025 -0500
treeff41c8832ef85496a7594aab4d6acefd9e3e8d3d
parentf3153347bb53a7ba600242c5d00ec5863fd4b4e4 [diff]
console-server: rework error path for realpath(../..) failure

We shouldn't hit this, as no tty paths will be directly under /sys. All
following code will require tty_device_tty_dir to be set, so use the
exit path without indicating an error.

Change-Id: I3a447d0fed6dda6372fed7a6c7879fad7f04f077
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
1 file changed
tree: ff41c8832ef85496a7594aab4d6acefd9e3e8d3d
  1. conf/
  2. docs/
  3. subprojects/
  4. test/
  5. .clang-format
  6. .clang-tidy
  7. .gitignore
  8. .travis.yml
  9. CHANGELOG.md
  10. config-internal.h
  11. config.c
  12. config.h
  13. console-client.c
  14. console-dbus.c
  15. console-mux.c
  16. console-mux.h
  17. console-server.c
  18. console-server.h
  19. console-socket.c
  20. LICENSE
  21. log-handler.c
  22. meson.build
  23. meson.options
  24. OWNERS
  25. README.md
  26. ringbuffer.c
  27. socket-handler.c
  28. tty-handler.c
  29. util.c
  30. util.h
README.md

obmc-console

To Build

To build this project, run the following shell commands:

meson setup build
meson compile -C build

To test:

dbus-run-session meson test -C build

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
        +---+--+  | console-id = "host0" |  |                     |  |  console-id = "host0"  |  +--------+-------+
            |     |                      |  +---------------------+  |                        |           |
            |     +----------------------+                           +------------------------+           |
            |                                                                                             |
            |                                                                                             |
            |                                                                                             |
            +---------------------------------------------------------------------------------------------+

This supports multiple independent consoles. The console-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.

Mux Support

In some hardware designs, multiple UARTS may be available behind a Mux. Please reference docs/mux-support.md in that case.

Sample Development Setup

For developing obmc-console, we can use pseudo terminals (pty's) in Linux.

The socat command will output names of 2 pty's, one of which is the master and the other one is the slave. The master pty can be used to emulate a UART.

$ socat -d -d pty,raw,echo=0,link=pty1 pty,raw,echo=0,link=pty2

$ obmc-console-server --console-id dev $(realpath pty2)

$ obmc-console-client -i dev

# this message should appear for the client
$ echo "hi" > pty1