nixpkgs-suyu/modules/testing/test-instrumentation.nix
Eelco Dolstra 90148d6fd1 Work around "Input/output error" opening /dev/ttyS0
E.g. http://hydra.nixos.org/build/5541847

This is a random occurence, maybe due to a race with something else.
So just retry until it works.
2013-07-16 15:04:32 +02:00

91 lines
2.9 KiB
Nix

# This module allows the test driver to connect to the virtual machine
# via a root shell attached to port 514.
{ config, pkgs, ... }:
with pkgs.lib;
let kernel = config.boot.kernelPackages.kernel; in
{
config = {
systemd.services.backdoor =
{ wantedBy = [ "multi-user.target" ];
requires = [ "dev-hvc0.device" "dev-ttyS0.device" ];
after = [ "dev-hvc0.device" "dev-ttyS0.device" ];
script =
''
export USER=root
export HOME=/root
export DISPLAY=:0.0
source /etc/profile
cd /tmp
exec < /dev/hvc0 > /dev/hvc0
while ! exec 2> /dev/ttyS0; do sleep 0.1; done
echo "connecting to host..." >&2
stty -F /dev/hvc0 raw -echo # prevent nl -> cr/nl conversion
echo
PS1= exec /bin/sh
'';
serviceConfig.KillSignal = "SIGHUP";
};
# Prevent agetty from being instantiated on ttyS0, since it
# interferes with the backdoor (writes to ttyS0 will randomly fail
# with EIO). Likewise for hvc0.
systemd.services."serial-getty@ttyS0".enable = false;
systemd.services."serial-getty@hvc0".enable = false;
boot.initrd.postDeviceCommands =
''
# Using acpi_pm as a clock source causes the guest clock to
# slow down under high host load. This is usually a bad
# thing, but for VM tests it should provide a bit more
# determinism (e.g. if the VM runs at lower speed, then
# timeouts in the VM should also be delayed).
echo acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource
'';
boot.postBootCommands =
''
# Panic on out-of-memory conditions rather than letting the
# OOM killer randomly get rid of processes, since this leads
# to failures that are hard to diagnose.
echo 2 > /proc/sys/vm/panic_on_oom
# Coverage data is written into /tmp/coverage-data.
mkdir -p /tmp/xchg/coverage-data
'';
# If the kernel has been built with coverage instrumentation, make
# it available under /proc/gcov.
boot.kernelModules = [ "gcov-proc" ];
# Panic if an error occurs in stage 1 (rather than waiting for
# user intervention).
boot.kernelParams =
[ "console=tty1" "console=ttyS0" "panic=1" "boot.panic_on_fail" ];
# `xwininfo' is used by the test driver to query open windows.
environment.systemPackages = [ pkgs.xorg.xwininfo ];
# Log everything to the serial console.
services.journald.console = "/dev/console";
# Prevent tests from accessing the Internet.
networking.defaultGateway = mkOverride 150 "";
networking.nameservers = mkOverride 150 [ ];
systemd.globalEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
system.requiredKernelConfig = with config.lib.kernelConfig; [
(isYes "SERIAL_8250_CONSOLE")
(isYes "SERIAL_8250")
(isEnabled "VIRTIO_CONSOLE")
];
};
}