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gerrit.openbmc.org / openbmc / obmc-console / refs/heads/master
commit375786fc0e8ce34d72bafffb03a28689df94fb62[log] [tgz]
authorDan Zhang <zhdaniel@google.com>Sun Feb 09 16:58:26 2025 +0000
committerAndrew Jeffery <andrew@codeconstruct.com.au>Fri Mar 21 00:14:11 2025 +0000
treee2be4765bbfca25004e3c3a975cdab77e8cd9bf7
parenta1f911aaf2b730005f9aebca1f7ff752add26e0a [diff]
Fix unexpected behavior in client_timeout() error handling

There are 4 places that call client_close(), 3 are in poller callback
function before return _REMOVE. The client_ringbuffer_poll() and
client_poll() both set the client->rbc = NULL or client->poller = NULL
correspondingly to avoid client_close() unregistering the poller within
poller callback. Because calling console_poller_unregister() within the
loop of console-sever.c:call_pollers() will make the loop writing into
freed poller, corrupting the memory and cause unexpected hehavior.

This fix is let the timeout callback follow the same pattern and avoid
calling console_poller_unregister() within call_pollers() loop.

Change-Id: If723a476d4142a42aa62e97ed0d2e2abca5e00c6
Signed-off-by: Dan Zhang <zhdaniel@google.com>
1 file changed
tree: e2be4765bbfca25004e3c3a975cdab77e8cd9bf7
  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