Investigating PR29796, where it was noticed that there was a delay when trying to quit the gdb session if connected to gdbserver via stdio. It was also mentioned that using --once when launching gdbserver would fix this problem and a recommendation was made to always apply --once when launching gdbserver with stdio.

I've explicitly set the run_once flag when stdio is detected at launch of gdbserver. This does fix the problem as suggested in the bug since the conditional at gdbserver/server.cc:3958 is always triggered.

```

if (run_once || (!extended_protocol && !target_running ()))

throw_quit ("Quit");

```

However, would it be better to create a new flag for this to facilitate quitting despite extended_protocol instead of piggybacking on --once logic?

Tested on x86_64 Ubuntu 22.04 natively

Testsuite had no regressions.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29796

---

diff --git a/gdbserver/server.cc b/gdbserver/server.cc

index e02cdb83b51..3c9e8bc3720 100644

--- a/gdbserver/server.cc

+++ b/gdbserver/server.cc

@@ -3760,6 +3760,8 @@ captured_main (int argc, char *argv[])

/* "-" specifies a stdio connection and is a form of port

specification. */

port = STDIO_CONNECTION_NAME;

+ /* auto-imply --once if invoked via stdio. */

+ run_once = true;

next_arg++;

break;

}

```

---