nixpkgs/nixos/modules/virtualisation/nixos-container.pl
Eelco Dolstra 6da72a4456 nixos-container: Rewrite in Perl
Also fix race condition when multiple containers are created
simultaneously (as NixOps tends to do).
2014-03-31 19:49:15 +02:00

199 lines
5.9 KiB
Perl
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#! @perl@
use strict;
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-shell <container-name>
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 "$0: invalid container name\n";
if ($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 $nixosConfig = <<EOF;
{ config, pkgs, ... }:
with pkgs.lib;
{ boot.isContainer = true;
security.initialRootPassword = mkDefault "!";
networking.hostName = mkDefault "$containerName";
networking.useDHCP = false;
imports = [ <nixpkgs/nixos/modules/virtualisation/container-login.nix> ];
$extraConfig
}
EOF
my $nixosConfigFile = "$root/etc/nixos/configuration.nix";
write_file($nixosConfigFile, $nixosConfig);
# 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 $confFile = "/etc/containers/$containerName.conf";
die "$0: container $containerName does not exist\n" if !-e $confFile;
sub stopContainer {
system("systemctl", "stop", "container\@$containerName") == 0
or die "$0: failed to stop container\n";
}
if ($action eq "destroy") {
my $root = "/var/lib/containers/$containerName";
my $profileDir = "/nix/var/nix/profiles/per-container/$containerName";
my $status = `systemctl show 'container\@$containerName'`;
stopContainer if $status =~ /ActiveState=active/;
rmtree($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 ($action eq "login") {
exec($socat, "unix:/var/lib/containers/$containerName/var/lib/login.socket", "-,echo=0,raw");
}
elsif ($action eq "root-shell") {
exec($socat, "unix:/var/lib/containers/$containerName/var/lib/root-shell.socket", "-");
}
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, "|-", $socat, "unix:/var/lib/containers/$containerName/var/lib/root-shell.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";
}