diff options
Diffstat (limited to 'nixos/modules/testing/test-instrumentation.nix')
| -rw-r--r-- | nixos/modules/testing/test-instrumentation.nix | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/nixos/modules/testing/test-instrumentation.nix b/nixos/modules/testing/test-instrumentation.nix new file mode 100644 index 00000000000..01447e6ada8 --- /dev/null +++ b/nixos/modules/testing/test-instrumentation.nix @@ -0,0 +1,141 @@ +# This module allows the test driver to connect to the virtual machine +# via a root shell attached to port 514. + +{ options, config, lib, pkgs, ... }: + +with lib; + +let + qemu-common = import ../../lib/qemu-common.nix { inherit lib pkgs; }; +in + +{ + + config = { + + systemd.services.backdoor = + { wantedBy = [ "multi-user.target" ]; + requires = [ "dev-hvc0.device" "dev-${qemu-common.qemuSerialDevice}.device" ]; + after = [ "dev-hvc0.device" "dev-${qemu-common.qemuSerialDevice}.device" ]; + script = + '' + export USER=root + export HOME=/root + export DISPLAY=:0.0 + + source /etc/profile + + # Don't use a pager when executing backdoor + # actions. Because we use a tty, commands like systemctl + # or nix-store get confused into thinking they're running + # interactively. + export PAGER= + + cd /tmp + exec < /dev/hvc0 > /dev/hvc0 + while ! exec 2> /dev/${qemu-common.qemuSerialDevice}; do sleep 0.1; done + echo "connecting to host..." >&2 + stty -F /dev/hvc0 raw -echo # prevent nl -> cr/nl conversion + echo + PS1= exec /bin/sh + ''; + serviceConfig.KillSignal = "SIGHUP"; + }; + + # Prevent agetty from being instantiated on the serial device, since it + # interferes with the backdoor (writes to it will randomly fail + # with EIO). Likewise for hvc0. + systemd.services."serial-getty@${qemu-common.qemuSerialDevice}".enable = false; + systemd.services."serial-getty@hvc0".enable = false; + + # Only set these settings when the options exist. Some tests (e.g. those + # that do not specify any nodes, or an empty attr set as nodes) will not + # have the QEMU module loaded and thuse these options can't and should not + # be set. + virtualisation = lib.optionalAttrs (options ? virtualisation.qemu) { + qemu = { + # Only use a serial console, no TTY. + # NOTE: optionalAttrs + # test-instrumentation.nix appears to be used without qemu-vm.nix, so + # we avoid defining consoles if not possible. + # TODO: refactor such that test-instrumentation can import qemu-vm + # or declare virtualisation.qemu.console option in a module that's always imported + consoles = [ qemu-common.qemuSerialDevice ]; + package = lib.mkDefault pkgs.qemu_test; + }; + }; + + boot.initrd.preDeviceCommands = + '' + echo 600 > /proc/sys/kernel/hung_task_timeout_secs + ''; + + 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 + ''; + + # Panic if an error occurs in stage 1 (rather than waiting for + # user intervention). + boot.kernelParams = + [ "console=${qemu-common.qemuSerialDevice}" "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.extraConfig = + '' + ForwardToConsole=yes + MaxLevelConsole=debug + ''; + + systemd.extraConfig = '' + # Don't clobber the console with duplicate systemd messages. + ShowStatus=no + # Allow very slow start + DefaultTimeoutStartSec=300 + ''; + systemd.user.extraConfig = '' + # Allow very slow start + DefaultTimeoutStartSec=300 + ''; + + boot.consoleLogLevel = 7; + + # Prevent tests from accessing the Internet. + networking.defaultGateway = mkOverride 150 ""; + networking.nameservers = mkOverride 150 [ ]; + + system.requiredKernelConfig = with config.lib.kernelConfig; [ + (isYes "SERIAL_8250_CONSOLE") + (isYes "SERIAL_8250") + (isEnabled "VIRTIO_CONSOLE") + ]; + + networking.usePredictableInterfaceNames = false; + + # Make it easy to log in as root when running the test interactively. + users.users.root.initialHashedPassword = mkOverride 150 ""; + + services.xserver.displayManager.job.logToJournal = true; + + # Make sure we use the Guest Agent from the QEMU package for testing + # to reduce the closure size required for the tests. + services.qemuGuest.package = pkgs.qemu_test.ga; + }; + +} |