1a82024dd8
Running agetty on ttyS0 interferes with the backdoor, which uses ttyS0 as its standard error. After agetty starts, writes to the stderr file descriptor will return EIO (though doing "exec 2>/proc/self/fd/2" will miracuously fix this). http://hydra.nixos.org/build/3252782
93 lines
2.9 KiB
Nix
93 lines
2.9 KiB
Nix
# This module allows the test driver to connect to the virtual machine
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# via a root shell attached to port 514.
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{ config, pkgs, ... }:
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with pkgs.lib;
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let kernel = config.boot.kernelPackages.kernel; in
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{
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config = {
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boot.systemd.services.backdoor =
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{ wantedBy = [ "multi-user.target" ];
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requires = [ "dev-hvc0.device" "dev-ttyS0.device" ];
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after = [ "dev-hvc0.device" "dev-ttyS0.device" ];
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script =
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''
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export USER=root
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export HOME=/root
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export DISPLAY=:0.0
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source /etc/profile
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cd /tmp
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exec < /dev/hvc0 > /dev/hvc0 2> /dev/ttyS0
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echo "connecting to host..." >&2
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stty -F /dev/hvc0 raw -echo # prevent nl -> cr/nl conversion
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echo
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PS1= exec /bin/sh
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'';
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};
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# Prevent agetty from being instantiated on ttyS0, since it
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# interferes with the backdoor (writes to ttyS0 will randomly fail
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# with EIO).
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boot.systemd.services."serial-getty@ttyS0".enable = false;
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boot.initrd.postDeviceCommands =
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''
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# Using acpi_pm as a clock source causes the guest clock to
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# slow down under high host load. This is usually a bad
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# thing, but for VM tests it should provide a bit more
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# determinism (e.g. if the VM runs at lower speed, then
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# timeouts in the VM should also be delayed).
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echo acpi_pm > /sys/devices/system/clocksource/clocksource0/current_clocksource
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'';
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boot.postBootCommands =
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''
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# Panic on out-of-memory conditions rather than letting the
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# OOM killer randomly get rid of processes, since this leads
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# to failures that are hard to diagnose.
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echo 2 > /proc/sys/vm/panic_on_oom
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# Coverage data is written into /tmp/coverage-data.
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mkdir -p /tmp/xchg/coverage-data
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# Mount debugfs to gain access to the kernel coverage data (if
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# available).
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mount -t debugfs none /sys/kernel/debug || true
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'';
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# If the kernel has been built with coverage instrumentation, make
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# it available under /proc/gcov.
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boot.kernelModules = [ "gcov-proc" ];
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# Panic if an error occurs in stage 1 (rather than waiting for
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# user intervention).
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boot.kernelParams =
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[ "console=tty1" "console=ttyS0" "panic=1" "stage1panic=1" ];
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# `xwininfo' is used by the test driver to query open windows.
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environment.systemPackages = [ pkgs.xorg.xwininfo ];
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# Log everything to the serial console.
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services.journald.console = "/dev/console";
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# Prevent tests from accessing the Internet.
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networking.defaultGateway = mkOverride 150 "";
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networking.nameservers = mkOverride 150 [ ];
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system.upstartEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
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system.requiredKernelConfig = with config.lib.kernelConfig; [
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(isYes "SERIAL_8250_CONSOLE")
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(isYes "SERIAL_8250")
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(isEnabled "VIRTIO_CONSOLE")
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];
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};
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}
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