Hi, I'm seeing the same issue on honister - is it possible to backport this patch? Cheers, Peter ________________________________ From: meta-arm@lists.yoctoproject.org on behalf of Ross Burton via lists.yoctoproject.org Sent: 21 October 2021 12:16 To: meta-arm@lists.yoctoproject.org Subject: [meta-arm] [PATCH v2] runfvp: Ensure new process group is in the foreground From: Peter Hoyes When a new process group is created, it is launched in the background and any attempt to access the session terminal triggers a SIGTTIN (for stdin) or SIGTTOU (for stdout) signal. These are ignored in an interactive shell, but the default signal behavior in a new job is to send a SIGTSTP to the whole process group. This causes runfvp to hang when executed via a subprocess when stdin is accessed. After creating a new process group, use tcsetpgrp to make the new group the foreground process for the terminal associated with stdin/stdout, but only if stdin is a tty. The documentation for tcsetgrp states that tcsetpgrp itself raises a SIGTTOU signal, so set this signal to SIG_IGN. Signed-off-by: Peter Hoyes Change-Id: I349a825df7fcb8a3cedb81762b901c6f50fa53b5 --- scripts/runfvp | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/scripts/runfvp b/scripts/runfvp index 97836726..66a76cc5 100755 --- a/scripts/runfvp +++ b/scripts/runfvp @@ -4,6 +4,7 @@ import asyncio import json import os import re +import signal import sys import subprocess import pathlib @@ -220,6 +221,9 @@ if __name__ == "__main__": # Set the process group so that it's possible to kill runfvp and # everything it spawns easily. os.setpgid(0, 0) + if sys.stdin.isatty(): + signal.signal(signal.SIGTTOU, signal.SIG_IGN) + os.tcsetpgrp(sys.stdin.fileno(), os.getpgrp()) runfvp(sys.argv[1:]) except KeyboardInterrupt: pass -- 2.25.1