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nixpkgs/nixos/modules/testing/test-instrumentation.nix
aszlig 6cfb3b6364
nixos/tests: Use a patched QEMU for testing
The reason to patch QEMU is that with latest Nix, tests like "printing"
or "misc" fail because they expect the store paths to be owned by uid 0
and gid 0.

Starting with NixOS/nix@5e51ffb1c2, Nix
builds inside of a new user namespace. Unfortunately this also means
that bind-mounted store paths that are part of the derivation's inputs
are no longer owned by uid 0 and gid 0 but by uid 65534 and gid 65534.

This in turn causes things like sudo or cups to fail with errors about
insecure file permissions.

So in order to avoid that, let's make sure the VM always gets files
owned by uid 0 and gid 0 and does a no-op when doing a chmod on a store
path.

In addition, this adds a virtualisation.qemu.program option so that we
can make sure that we only use the patched version if we're *really*
running NixOS VM tests (that is, whenever we have imported
test-instrumentation.nix).

Tested against the "misc" and "printing" tests.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
2016-11-17 17:16:16 +01:00

132 lines
4.1 KiB
Nix

# This module allows the test driver to connect to the virtual machine
# via a root shell attached to port 514.
{ config, lib, pkgs, ... }:
with 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
# 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/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.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
# 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=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.extraConfig =
''
ForwardToConsole=yes
MaxLevelConsole=debug
'';
# Don't clobber the console with duplicate systemd messages.
systemd.extraConfig = "ShowStatus=no";
boot.consoleLogLevel = 7;
# 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")
];
networking.usePredictableInterfaceNames = false;
# Make sure we use a patched QEMU that ignores file ownership.
virtualisation.qemu.program = "${pkgs.qemu_test}/bin/qemu-kvm";
# Make it easy to log in as root when running the test interactively.
users.extraUsers.root.initialHashedPassword = mkOverride 150 "";
services.xserver.displayManager.logToJournal = true;
# Bump kdm's X server start timeout to account for heavily loaded
# VM host systems.
services.xserver.displayManager.kdm.extraConfig =
''
[X-:*-Core]
ServerTimeout=240
'';
};
}