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nixpkgs/nixos/modules/virtualisation/nixos-container.pl
Eelco Dolstra 29027fd1e1 Rewrite ‘with pkgs.lib’ -> ‘with lib’
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
2014-04-14 16:26:48 +02:00

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Perl
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#! @perl@
use strict;
use POSIX;
use File::Path;
use File::Slurp;
use Fcntl ':flock';
use Getopt::Long qw(:config gnu_getopt);
my $socat = '@socat@/bin/socat';
# Parse the command line.
sub showHelp {
print <<EOF;
Usage: nixos-container list
nixos-container create <container-name> [--config <string>] [--ensure-unique-name]
nixos-container destroy <container-name>
nixos-container start <container-name>
nixos-container stop <container-name>
nixos-container login <container-name>
nixos-container root-login <container-name>
nixos-container run <container-name> -- args...
nixos-container set-root-password <container-name> <password>
nixos-container show-ip <container-name>
EOF
exit 0;
}
my $ensureUniqueName = 0;
my $extraConfig = "";
GetOptions(
"help" => sub { showHelp() },
"ensure-unique-name" => \$ensureUniqueName,
"config=s" => \$extraConfig
) or exit 1;
my $action = $ARGV[0] or die "$0: no action specified\n";
# Execute the selected action.
mkpath("/etc/containers", 0, 0755);
mkpath("/var/lib/containers", 0, 0700);
if ($action eq "list") {
foreach my $confFile (glob "/etc/containers/*.conf") {
$confFile =~ /\/([^\/]+).conf$/ or next;
print "$1\n";
}
exit 0;
}
my $containerName = $ARGV[1] or die "$0: no container name specified\n";
$containerName =~ /^[a-zA-Z0-9\-]+$/ or die "$0: invalid container name\n";
sub writeNixOSConfig {
my ($nixosConfigFile) = @_;
my $nixosConfig = <<EOF;
{ config, lib, pkgs, ... }:
with lib;
{ boot.isContainer = true;
security.initialRootPassword = mkDefault "!";
networking.hostName = mkDefault "$containerName";
networking.useDHCP = false;
$extraConfig
}
EOF
write_file($nixosConfigFile, $nixosConfig);
}
if ($action eq "create") {
# Acquire an exclusive lock to prevent races with other
# invocations of nixos-container create.
my $lockFN = "/run/lock/nixos-container";
open(my $lock, '>>', $lockFN) or die "$0: opening $lockFN: $!";
flock($lock, LOCK_EX) or die "$0: could not lock $lockFN: $!";
my $confFile = "/etc/containers/$containerName.conf";
my $root = "/var/lib/containers/$containerName";
# Maybe generate a unique name.
if ($ensureUniqueName) {
my $base = $containerName;
for (my $nr = 0; ; $nr++) {
$containerName = "$base-$nr";
$confFile = "/etc/containers/$containerName.conf";
$root = "/var/lib/containers/$containerName";
last unless -e $confFile || -e $root;
}
}
die "$0: container $containerName already exists\n" if -e $confFile;
# Get an unused IP address.
my %usedIPs;
foreach my $confFile2 (glob "/etc/containers/*.conf") {
my $s = read_file($confFile2) or die;
$usedIPs{$1} = 1 if $s =~ /^HOST_ADDRESS=([0-9\.]+)$/m;
$usedIPs{$1} = 1 if $s =~ /^LOCAL_ADDRESS=([0-9\.]+)$/m;
}
my ($ipPrefix, $hostAddress, $localAddress);
for (my $nr = 1; $nr < 255; $nr++) {
$ipPrefix = "10.233.$nr";
$hostAddress = "$ipPrefix.1";
$localAddress = "$ipPrefix.2";
last unless $usedIPs{$hostAddress} || $usedIPs{$localAddress};
$ipPrefix = undef;
}
die "$0: out of IP addresses\n" unless defined $ipPrefix;
my @conf;
push @conf, "PRIVATE_NETWORK=1\n";
push @conf, "HOST_ADDRESS=$hostAddress\n";
push @conf, "LOCAL_ADDRESS=$localAddress\n";
write_file($confFile, \@conf);
close($lock);
print STDERR "host IP is $hostAddress, container IP is $localAddress\n";
mkpath("$root/etc/nixos", 0, 0755);
my $nixosConfigFile = "$root/etc/nixos/configuration.nix";
writeNixOSConfig $nixosConfigFile;
# The per-container directory is restricted to prevent users on
# the host from messing with guest users who happen to have the
# same uid.
my $profileDir = "/nix/var/nix/profiles/per-container";
mkpath($profileDir, 0, 0700);
$profileDir = "$profileDir/$containerName";
mkpath($profileDir, 0, 0755);
system("nix-env", "-p", "$profileDir/system",
"-I", "nixos-config=$nixosConfigFile", "-f", "<nixpkgs/nixos>",
"--set", "-A", "system") == 0
or die "$0: failed to build initial container configuration\n";
print "$containerName\n" if $ensureUniqueName;
exit 0;
}
my $root = "/var/lib/containers/$containerName";
my $profileDir = "/nix/var/nix/profiles/per-container/$containerName";
my $confFile = "/etc/containers/$containerName.conf";
die "$0: container $containerName does not exist\n" if !-e $confFile;
sub isContainerRunning {
my $status = `systemctl show 'container\@$containerName'`;
return $status =~ /ActiveState=active/;
}
sub stopContainer {
system("systemctl", "stop", "container\@$containerName") == 0
or die "$0: failed to stop container\n";
}
if ($action eq "destroy") {
die "$0: cannot destroy declarative container (remove it from your configuration.nix instead)\n"
unless POSIX::access($confFile, &POSIX::W_OK);
stopContainer if isContainerRunning;
rmtree($profileDir) if -e $profileDir;
rmtree($root) if -e $root;
unlink($confFile) or die;
}
elsif ($action eq "start") {
system("systemctl", "start", "container\@$containerName") == 0
or die "$0: failed to start container\n";
}
elsif ($action eq "stop") {
stopContainer;
}
elsif ($action eq "update") {
my $nixosConfigFile = "$root/etc/nixos/configuration.nix";
# FIXME: may want to be more careful about clobbering the existing
# configuration.nix.
writeNixOSConfig $nixosConfigFile if defined $extraConfig;
system("nix-env", "-p", "$profileDir/system",
"-I", "nixos-config=$nixosConfigFile", "-f", "<nixpkgs/nixos>",
"--set", "-A", "system") == 0
or die "$0: failed to build container configuration\n";
if (isContainerRunning) {
print STDERR "reloading container...\n";
system("systemctl", "reload", "container\@$containerName") == 0
or die "$0: failed to reload container\n";
}
}
elsif ($action eq "login") {
exec($socat, "unix:$root/var/lib/login.socket", "-,echo=0,raw");
}
elsif ($action eq "root-login") {
exec($socat, "unix:$root/var/lib/root-login.socket", "-,echo=0,raw");
}
elsif ($action eq "run") {
shift @ARGV; shift @ARGV;
open(SOCAT, "|-", $socat, "unix:$root/var/lib/run-command.socket", "-");
print SOCAT join(' ', map { "'$_'" } @ARGV), "\n";
close(SOCAT);
}
elsif ($action eq "set-root-password") {
# FIXME: don't get password from the command line.
my $password = $ARGV[2] or die "$0: no password given\n";
open(SOCAT, "|-", $socat, "unix:$root/var/lib/run-command.socket", "-");
print SOCAT "passwd\n";
print SOCAT "$password\n";
print SOCAT "$password\n";
close(SOCAT);
}
elsif ($action eq "show-ip") {
my $s = read_file($confFile) or die;
$s =~ /^LOCAL_ADDRESS=([0-9\.]+)$/m or die "$0: cannot get IP address\n";
print "$1\n";
}
else {
die "$0: unknown action $action\n";
}