nixos-infect/nixos-infect
2023-02-03 11:39:45 -08:00

386 lines
12 KiB
Bash

#! /usr/bin/env bash
# More info at: https://github.com/elitak/nixos-infect
set -e -o pipefail
makeConf() {
# Skip everything if main config already present
[[ -e /etc/nixos/configuration.nix ]] && return 0
# Lightsail config is not like the others
if [ "$PROVIDER" = "lightsail" ]; then
makeLightsailConf
return 0
fi
# NB <<"EOF" quotes / $ ` in heredocs, <<EOF does not
mkdir -p /etc/nixos
# Prevent grep for sending error code 1 (and halting execution) when no lines are selected : https://www.unix.com/man-page/posix/1P/grep
local IFS=$'\n'
for trypath in /root/.ssh/authorized_keys /home/$SUDO_USER/.ssh/authorized_keys $HOME/.ssh/authorized_keys; do
[[ -r "$trypath" ]] \
&& keys=$(sed -E 's/^.*((ssh|ecdsa)-[^[:space:]]+)[[:space:]]+([^[:space:]]+)([[:space:]]*.*)$/\1 \3\4/' "$trypath") \
&& break
done
local network_import=""
[[ -n "$doNetConf" ]] && network_import="./networking.nix # generated at runtime by nixos-infect"
cat > /etc/nixos/configuration.nix << EOF
{ ... }: {
imports = [
./hardware-configuration.nix
$network_import
$NIXOS_IMPORT
];
boot.cleanTmpDir = true;
zramSwap.enable = ${zramswap};
networking.hostName = "$(hostname -s)";
networking.domain = "$(hostname -d)";
services.openssh.enable = true;
users.users.root.openssh.authorizedKeys.keys = [$(while read -r line; do echo -n "
\"$line\" "; done <<< "$keys")
];
}
EOF
if isEFI; then
bootcfg=$(cat << EOF
boot.loader.grub = {
efiSupport = true;
efiInstallAsRemovable = true;
device = "nodev";
};
fileSystems."/boot" = { device = "$esp"; fsType = "vfat"; };
EOF
)
else
bootcfg=$(cat << EOF
boot.loader.grub.device = "$grubdev";
EOF
)
fi
availableKernelModules=('"ata_piix"' '"uhci_hcd"' '"xen_blkfront"')
if isX86_64; then
availableKernelModules+=('"vmw_pvscsi"')
fi
# If you rerun this later, be sure to prune the filesSystems attr
cat > /etc/nixos/hardware-configuration.nix << EOF
{ modulesPath, ... }:
{
imports = [ (modulesPath + "/profiles/qemu-guest.nix") ];
$bootcfg
boot.initrd.availableKernelModules = [ ${availableKernelModules[@]} ];
boot.initrd.kernelModules = [ "nvme" ];
fileSystems."/" = { device = "$rootfsdev"; fsType = "$rootfstype"; };
$swapcfg
}
EOF
[[ -n "$doNetConf" ]] && makeNetworkingConf || true
}
makeLightsailConf() {
mkdir -p /etc/nixos
cat > /etc/nixos/configuration.nix << EOF
{ config, pkgs, modulesPath, ... }:
{
imports = [ "\${modulesPath}/virtualisation/amazon-image.nix" ];
}
EOF
}
makeNetworkingConf() {
# XXX It'd be better if we used procfs for all this...
local IFS=$'\n'
eth0_name=$(ip address show | grep '^2:' | awk -F': ' '{print $2}')
eth0_ip4s=$(ip address show dev "$eth0_name" | grep 'inet ' | sed -r 's|.*inet ([0-9.]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|')
eth0_ip6s=$(ip address show dev "$eth0_name" | grep 'inet6 ' | sed -r 's|.*inet6 ([0-9a-f:]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|' || '')
gateway=$(ip route show dev "$eth0_name" | grep default | sed -r 's|default via ([0-9.]+).*|\1|')
gateway6=$(ip -6 route show dev "$eth0_name" | grep default | sed -r 's|default via ([0-9a-f:]+).*|\1|' || true)
ether0=$(ip address show dev "$eth0_name" | grep link/ether | sed -r 's|.*link/ether ([0-9a-f:]+) .*|\1|')
eth1_name=$(ip address show | grep '^3:' | awk -F': ' '{print $2}')||true
if [ -n "$eth1_name" ];then
eth1_ip4s=$(ip address show dev "$eth1_name" | grep 'inet ' | sed -r 's|.*inet ([0-9.]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|')
eth1_ip6s=$(ip address show dev "$eth1_name" | grep 'inet6 ' | sed -r 's|.*inet6 ([0-9a-f:]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|' || '')
ether1=$(ip address show dev "$eth1_name" | grep link/ether | sed -r 's|.*link/ether ([0-9a-f:]+) .*|\1|')
interfaces1=<< EOF
$eth1_name = {
ipv4.addresses = [$(for a in "${eth1_ip4s[@]}"; do echo -n "
$a"; done)
];
ipv6.addresses = [$(for a in "${eth1_ip6s[@]}"; do echo -n "
$a"; done)
];
EOF
extraRules1="ATTR{address}==\"${ether1}\", NAME=\"${eth1_name}\""
else
interfaces1=""
extraRules1=""
fi
readarray nameservers < <(grep ^nameserver /etc/resolv.conf | sed -r \
-e 's/^nameserver[[:space:]]+([0-9.a-fA-F:]+).*/"\1"/' \
-e 's/127[0-9.]+/8.8.8.8/' \
-e 's/::1/8.8.8.8/' )
if [[ "$eth0_name" = eth* ]]; then
predictable_inames="usePredictableInterfaceNames = lib.mkForce false;"
else
predictable_inames="usePredictableInterfaceNames = lib.mkForce true;"
fi
cat > /etc/nixos/networking.nix << EOF
{ lib, ... }: {
# This file was populated at runtime with the networking
# details gathered from the active system.
networking = {
nameservers = [ ${nameservers[@]} ];
defaultGateway = "${gateway}";
defaultGateway6 = {
address = "${gateway6}";
interface = "${eth0_name}";
};
dhcpcd.enable = false;
$predictable_inames
interfaces = {
$eth0_name = {
ipv4.addresses = [$(for a in "${eth0_ip4s[@]}"; do echo -n "
$a"; done)
];
ipv6.addresses = [$(for a in "${eth0_ip6s[@]}"; do echo -n "
$a"; done)
];
ipv4.routes = [ { address = "${gateway}"; prefixLength = 32; } ];
ipv6.routes = [ { address = "${gateway6}"; prefixLength = 128; } ];
};
$interfaces1
};
};
services.udev.extraRules = ''
ATTR{address}=="${ether0}", NAME="${eth0_name}"
$extraRules1
'';
}
EOF
}
checkExistingSwap() {
SWAPSHOW=$(swapon --show --noheadings --raw)
zramswap=true
swapcfg=""
if [[ -n "$SWAPSHOW" ]]; then
SWAP_DEVICE="${SWAPSHOW%% *}"
if [[ "$SWAP_DEVICE" == "/dev/"* ]]; then
zramswap=false
swapcfg="swapDevices = [ { device = \"${SWAP_DEVICE}\"; } ];"
NO_SWAP=true
fi
fi
}
makeSwap() {
swapFile=$(mktemp /tmp/nixos-infect.XXXXX.swp)
dd if=/dev/zero "of=$swapFile" bs=1M count=$((1*1024))
chmod 0600 "$swapFile"
mkswap "$swapFile"
swapon -v "$swapFile"
}
removeSwap() {
swapoff -a
rm -vf /tmp/nixos-infect.*.swp
}
isX86_64() {
[[ "$(uname -m)" == "x86_64" ]]
}
isEFI() {
[ -d /sys/firmware/efi ]
}
findESP() {
esp=""
for d in /boot/EFI /boot/efi /boot; do
[[ ! -d "$d" ]] && continue
[[ "$d" == "$(df "$d" --output=target | sed 1d)" ]] \
&& esp="$(df "$d" --output=source | sed 1d)" \
&& break
done
[[ -z "$esp" ]] && { echo "ERROR: No ESP mount point found"; return 1; }
for uuid in /dev/disk/by-uuid/*; do
[[ $(readlink -f "$uuid") == "$esp" ]] && echo $uuid && return 0
done
}
prepareEnv() {
# $esp and $grubdev are used in makeConf()
if isEFI; then
esp="$(findESP)"
else
for grubdev in /dev/vda /dev/sda /dev/xvda /dev/nvme0n1 ; do [[ -e $grubdev ]] && break; done
fi
# Retrieve root fs block device
# (get root mount) (get partition or logical volume)
rootfsdev=$(mount | grep "on / type" | awk '{print $1;}')
rootfstype=$(df $rootfsdev --output=fstype | sed 1d)
# DigitalOcean doesn't seem to set USER while running user data
export USER="root"
export HOME="/root"
# Nix installer tries to use sudo regardless of whether we're already uid 0
#which sudo || { sudo() { eval "$@"; }; export -f sudo; }
# shellcheck disable=SC2174
mkdir -p -m 0755 /nix
}
fakeCurlUsingWget() {
# Use adapted wget if curl is missing
which wget && { \
curl() {
eval "wget $(
(local isStdout=1
for arg in "$@"; do
case "$arg" in
"-o")
echo "-O";
isStdout=0
;;
"-O")
isStdout=0
;;
"-L")
;;
*)
echo "$arg"
;;
esac
done;
[[ $isStdout -eq 1 ]] && echo "-O-"
)| tr '\n' ' '
)"
}; export -f curl; }
}
req() {
type "$1" > /dev/null 2>&1 || which "$1" > /dev/null 2>&1
}
checkEnv() {
[[ "$(whoami)" == "root" ]] || { echo "ERROR: Must run as root"; return 1; }
# Perform some easy fixups before checking
# TODO prevent multiple calls to apt-get update
(which dnf && dnf install -y perl-Digest-SHA) || true # Fedora 24
which bzcat || (which yum && yum install -y bzip2) \
|| (which apt-get && apt-get update && apt-get install -y bzip2) \
|| true
which xzcat || (which yum && yum install -y xz-utils) \
|| (which apt-get && apt-get update && apt-get install -y xz-utils) \
|| true
which curl || fakeCurlUsingWget \
|| (which apt-get && apt-get update && apt-get install -y curl) \
|| true
req curl || req wget || { echo "ERROR: Missing both curl and wget"; return 1; }
req bzcat || { echo "ERROR: Missing bzcat"; return 1; }
req xzcat || { echo "ERROR: Missing xzcat"; return 1; }
req groupadd || { echo "ERROR: Missing groupadd"; return 1; }
req useradd || { echo "ERROR: Missing useradd"; return 1; }
req ip || { echo "ERROR: Missing ip"; return 1; }
req awk || { echo "ERROR: Missing awk"; return 1; }
req cut || req df || { echo "ERROR: Missing coreutils (cut, df)"; return 1; }
# On some versions of Oracle Linux these have the wrong permissions,
# which stops sshd from starting when NixOS boots
chmod 600 /etc/ssh/ssh_host_*_key
}
infect() {
# Add nix build users
# FIXME run only if necessary, rather than defaulting true
groupadd nixbld -g 30000 || true
for i in {1..10}; do
useradd -c "Nix build user $i" -d /var/empty -g nixbld -G nixbld -M -N -r -s "$(which nologin)" "nixbld$i" || true
done
# TODO use addgroup and adduser as fallbacks
#addgroup nixbld -g 30000 || true
#for i in {1..10}; do adduser -DH -G nixbld nixbld$i || true; done
curl -L https://nixos.org/nix/install | sh
# shellcheck disable=SC1090
source ~/.nix-profile/etc/profile.d/nix.sh
[[ -z "$NIX_CHANNEL" ]] && NIX_CHANNEL="nixos-22.05"
nix-channel --remove nixpkgs
nix-channel --add "https://nixos.org/channels/$NIX_CHANNEL" nixos
nix-channel --update
export NIXOS_CONFIG="${NIXOS_CONFIG:-/etc/nixos/configuration.nix}"
nix-env --set \
-I nixpkgs=$HOME/.nix-defexpr/channels/nixos \
-f '<nixpkgs/nixos>' \
-p /nix/var/nix/profiles/system \
-A system
# Remove nix installed with curl | bash
rm -fv /nix/var/nix/profiles/default*
/nix/var/nix/profiles/system/sw/bin/nix-collect-garbage
# Reify resolv.conf
[[ -L /etc/resolv.conf ]] && mv -v /etc/resolv.conf /etc/resolv.conf.lnk && cat /etc/resolv.conf.lnk > /etc/resolv.conf
# Set label of root partition
if [ -n "$newrootfslabel" ]; then
echo "Setting label of $rootfsdev to $newrootfslabel"
e2label "$rootfsdev" "$newrootfslabel"
fi
# Stage the Nix coup d'état
touch /etc/NIXOS
echo etc/nixos >> /etc/NIXOS_LUSTRATE
echo etc/resolv.conf >> /etc/NIXOS_LUSTRATE
echo root/.nix-defexpr/channels >> /etc/NIXOS_LUSTRATE
(cd / && ls etc/ssh/ssh_host_*_key* || true) >> /etc/NIXOS_LUSTRATE
rm -rf /boot.bak
isEFI && umount "$esp"
mv -v /boot /boot.bak || { cp -a /boot /boot.bak ; rm -rf /boot/* ; umount /boot ; }
if isEFI; then
mkdir -p /boot
mount "$esp" /boot
find /boot -depth ! -path /boot -exec rm -rf {} +
fi
/nix/var/nix/profiles/system/bin/switch-to-configuration boot
}
[ "$PROVIDER" = "digitalocean" ] && doNetConf=y # digitalocean requires detailed network config to be generated
[ "$PROVIDER" = "lightsail" ] && newrootfslabel="nixos"
if [[ "$PROVIDER" = "digitalocean" ]] || [[ "$PROVIDER" = "servarica" ]] || [[ "$PROVIDER" = "hetznercloud" ]]; then
doNetConf=y # some providers require detailed network config to be generated
fi
checkEnv
prepareEnv
checkExistingSwap
if [[ -z "$NO_SWAP" ]]; then
makeSwap # smallest (512MB) droplet needs extra memory!
fi
makeConf
infect
if [[ -z "$NO_SWAP" ]]; then
removeSwap
fi
if [[ -z "$NO_REBOOT" ]]; then
reboot
fi