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#! @perl@
use strict;
use warnings;
use File::Basename;
use File::Slurp;
use Net::DBus;
use Sys::Syslog qw(:standard :macros);
use Cwd 'abs_path';
my $out = "@out@";
# To be robust against interruption, record what units need to be started etc.
my $startListFile = "/run/systemd/start-list";
my $restartListFile = "/run/systemd/restart-list";
my $reloadListFile = "/run/systemd/reload-list";
my $action = shift @ARGV;
if ("@localeArchive@" ne "") {
$ENV{LOCALE_ARCHIVE} = "@localeArchive@";
}
if (!defined $action || ($action ne "switch" && $action ne "boot" && $action ne "test" && $action ne "dry-activate")) {
print STDERR <<EOF;
Usage: $0 [switch|boot|test]
switch: make the configuration the boot default and activate now
boot: make the configuration the boot default
test: activate the configuration, but don\'t make it the boot default
dry-activate: show what would be done if this configuration were activated
EOF
exit 1;
}
# This is a NixOS installation if it has /etc/NIXOS or a proper
# /etc/os-release.
die "This is not a NixOS installation!\n" unless
-f "/etc/NIXOS" || (read_file("/etc/os-release", err_mode => 'quiet') // "") =~ /ID=nixos/s;
openlog("nixos", "", LOG_USER);
# Install or update the bootloader.
if ($action eq "switch" || $action eq "boot") {
system("@installBootLoader@ $out") == 0 or exit 1;
}
# Just in case the new configuration hangs the system, do a sync now.
system("@coreutils@/bin/sync", "-f", "/nix/store") unless ($ENV{"NIXOS_NO_SYNC"} // "") eq "1";
exit 0 if $action eq "boot";
# Check if we can activate the new configuration.
my $oldVersion = read_file("/run/current-system/init-interface-version", err_mode => 'quiet') // "";
my $newVersion = read_file("$out/init-interface-version");
if ($newVersion ne $oldVersion) {
print STDERR <<EOF;
Warning: the new NixOS configuration has an ‘init’ that is
incompatible with the current configuration. The new configuration
won\'t take effect until you reboot the system.
EOF
exit 100;
}
# Ignore SIGHUP so that we're not killed if we're running on (say)
# virtual console 1 and we restart the "tty1" unit.
$SIG{PIPE} = "IGNORE";
sub getActiveUnits {
my $mgr = Net::DBus->system->get_service("org.freedesktop.systemd1")->get_object("/org/freedesktop/systemd1");
my $units = $mgr->ListUnitsByPatterns([], []);
my $res = {};
for my $item (@$units) {
my ($id, $description, $load_state, $active_state, $sub_state,
$following, $unit_path, $job_id, $job_type, $job_path) = @$item;
next unless $following eq '';
next if $job_id == 0 and $active_state eq 'inactive';
$res->{$id} = { load => $load_state, state => $active_state, substate => $sub_state };
}
return $res;
}
sub parseFstab {
my ($filename) = @_;
my ($fss, $swaps);
foreach my $line (read_file($filename, err_mode => 'quiet')) {
chomp $line;
$line =~ s/^\s*#.*//;
next if $line =~ /^\s*$/;
my @xs = split / /, $line;
if ($xs[2] eq "swap") {
$swaps->{$xs[0]} = { options => $xs[3] // "" };
} else {
$fss->{$xs[1]} = { device => $xs[0], fsType => $xs[2], options => $xs[3] // "" };
}
}
return ($fss, $swaps);
}
sub parseUnit {
my ($filename) = @_;
my $info = {};
parseKeyValues($info, read_file($filename)) if -f $filename;
parseKeyValues($info, read_file("${filename}.d/overrides.conf")) if -f "${filename}.d/overrides.conf";
return $info;
}
sub parseKeyValues {
my $info = shift;
foreach my $line (@_) {
# FIXME: not quite correct.
$line =~ /^([^=]+)=(.*)$/ or next;
$info->{$1} = $2;
}
}
sub boolIsTrue {
my ($s) = @_;
return $s eq "yes" || $s eq "true";
}
sub recordUnit {
my ($fn, $unit) = @_;
write_file($fn, { append => 1 }, "$unit\n") if $action ne "dry-activate";
}
# As a fingerprint for determining whether a unit has changed, we use
# its absolute path. If it has an override file, we append *its*
# absolute path as well.
sub fingerprintUnit {
my ($s) = @_;
return abs_path($s) . (-f "${s}.d/overrides.conf" ? " " . abs_path "${s}.d/overrides.conf" : "");
}
# Figure out what units need to be stopped, started, restarted or reloaded.
my (%unitsToStop, %unitsToSkip, %unitsToStart, %unitsToRestart, %unitsToReload);
my %unitsToFilter; # units not shown
$unitsToStart{$_} = 1 foreach
split('\n', read_file($startListFile, err_mode => 'quiet') // "");
$unitsToRestart{$_} = 1 foreach
split('\n', read_file($restartListFile, err_mode => 'quiet') // "");
$unitsToReload{$_} = 1 foreach
split '\n', read_file($reloadListFile, err_mode => 'quiet') // "";
my $activePrev = getActiveUnits;
while (my ($unit, $state) = each %{$activePrev}) {
my $baseUnit = $unit;
my $prevUnitFile = "/etc/systemd/system/$baseUnit";
my $newUnitFile = "$out/etc/systemd/system/$baseUnit";
# Detect template instances.
if (!-e $prevUnitFile && !-e $newUnitFile && $unit =~ /^(.*)@[^\.]*\.(.*)$/) {
$baseUnit = "$1\@.$2";
$prevUnitFile = "/etc/systemd/system/$baseUnit";
$newUnitFile = "$out/etc/systemd/system/$baseUnit";
}
my $baseName = $baseUnit;
$baseName =~ s/\.[a-z]*$//;
if (-e $prevUnitFile && ($state->{state} eq "active" || $state->{state} eq "activating")) {
if (! -e $newUnitFile || abs_path($newUnitFile) eq "/dev/null") {
# Ignore (i.e. never stop) these units:
if ($unit eq "system.slice") {
# TODO: This can be removed a few months after 18.09 is out
# (i.e. after everyone switched away from 18.03).
# Problem: Restarting (stopping) system.slice would not only
# stop X11 but also most system units/services. We obviously
# don't want this happening to users when they switch from 18.03
# to 18.09 or nixos-unstable.
# Reason: The following change in systemd:
# https://github.com/systemd/systemd/commit/d8e5a9338278d6602a0c552f01f298771a384798
# The commit adds system.slice to the perpetual units, which
# means removing the unit file and adding it to the source code.
# This is done so that system.slice can't be stopped anymore but
# in our case it ironically would cause this script to stop
# system.slice because the unit was removed (and an older
# systemd version is still running).
next;
}
my $unitInfo = parseUnit($prevUnitFile);
$unitsToStop{$unit} = 1 if boolIsTrue($unitInfo->{'X-StopOnRemoval'} // "yes");
}
elsif ($unit =~ /\.target$/) {
my $unitInfo = parseUnit($newUnitFile);
# Cause all active target units to be restarted below.
# This should start most changed units we stop here as
# well as any new dependencies (including new mounts and
# swap devices). FIXME: the suspend target is sometimes
# active after the system has resumed, which probably
# should not be the case. Just ignore it.
if ($unit ne "suspend.target" && $unit ne "hibernate.target" && $unit ne "hybrid-sleep.target") {
unless (boolIsTrue($unitInfo->{'RefuseManualStart'} // "no")) {
$unitsToStart{$unit} = 1;
recordUnit($startListFile, $unit);
# Don't spam the user with target units that always get started.
$unitsToFilter{$unit} = 1;
}
}
# Stop targets that have X-StopOnReconfiguration set.
# This is necessary to respect dependency orderings
# involving targets: if unit X starts after target Y and
# target Y starts after unit Z, then if X and Z have both
# changed, then X should be restarted after Z. However,
# if target Y is in the "active" state, X and Z will be
# restarted at the same time because X's dependency on Y
# is already satisfied. Thus, we need to stop Y first.
# Stopping a target generally has no effect on other units
# (unless there is a PartOf dependency), so this is just a
# bookkeeping thing to get systemd to do the right thing.
if (boolIsTrue($unitInfo->{'X-StopOnReconfiguration'} // "no")) {
$unitsToStop{$unit} = 1;
}
}
elsif (fingerprintUnit($prevUnitFile) ne fingerprintUnit($newUnitFile)) {
if ($unit eq "sysinit.target" || $unit eq "basic.target" || $unit eq "multi-user.target" || $unit eq "graphical.target") {
# Do nothing. These cannot be restarted directly.
} elsif ($unit =~ /\.mount$/) {
# Reload the changed mount unit to force a remount.
$unitsToReload{$unit} = 1;
recordUnit($reloadListFile, $unit);
} elsif ($unit =~ /\.socket$/ || $unit =~ /\.path$/ || $unit =~ /\.slice$/) {
# FIXME: do something?
} else {
my $unitInfo = parseUnit($newUnitFile);
if (boolIsTrue($unitInfo->{'X-ReloadIfChanged'} // "no")) {
$unitsToReload{$unit} = 1;
recordUnit($reloadListFile, $unit);
}
elsif (!boolIsTrue($unitInfo->{'X-RestartIfChanged'} // "yes") || boolIsTrue($unitInfo->{'RefuseManualStop'} // "no") ) {
$unitsToSkip{$unit} = 1;
} else {
if (!boolIsTrue($unitInfo->{'X-StopIfChanged'} // "yes")) {
# This unit should be restarted instead of
# stopped and started.
$unitsToRestart{$unit} = 1;
recordUnit($restartListFile, $unit);
} else {
# If this unit is socket-activated, then stop the
# socket unit(s) as well, and restart the
# socket(s) instead of the service.
my $socketActivated = 0;
if ($unit =~ /\.service$/) {
my @sockets = split / /, ($unitInfo->{Sockets} // "");
if (scalar @sockets == 0) {
@sockets = ("$baseName.socket");
}
foreach my $socket (@sockets) {
if (defined $activePrev->{$socket}) {
$unitsToStop{$socket} = 1;
$unitsToStart{$socket} = 1;
recordUnit($startListFile, $socket);
$socketActivated = 1;
}
}
}
# If the unit is not socket-activated, record
# that this unit needs to be started below.
# We write this to a file to ensure that the
# service gets restarted if we're interrupted.
if (!$socketActivated) {
$unitsToStart{$unit} = 1;
recordUnit($startListFile, $unit);
}
$unitsToStop{$unit} = 1;
}
}
}
}
}
}
sub pathToUnitName {
my ($path) = @_;
# Use current version of systemctl binary before daemon is reexeced.
open my $cmd, "-|", "/run/current-system/sw/bin/systemd-escape", "--suffix=mount", "-p", $path
or die "Unable to escape $path!\n";
my $escaped = join "", <$cmd>;
chomp $escaped;
close $cmd or die;
return $escaped;
}
sub unique {
my %seen;
my @res;
foreach my $name (@_) {
next if $seen{$name};
$seen{$name} = 1;
push @res, $name;
}
return @res;
}
# Compare the previous and new fstab to figure out which filesystems
# need a remount or need to be unmounted. New filesystems are mounted
# automatically by starting local-fs.target. FIXME: might be nicer if
# we generated units for all mounts; then we could unify this with the
# unit checking code above.
my ($prevFss, $prevSwaps) = parseFstab "/etc/fstab";
my ($newFss, $newSwaps) = parseFstab "$out/etc/fstab";
foreach my $mountPoint (keys %$prevFss) {
my $prev = $prevFss->{$mountPoint};
my $new = $newFss->{$mountPoint};
my $unit = pathToUnitName($mountPoint);
if (!defined $new) {
# Filesystem entry disappeared, so unmount it.
$unitsToStop{$unit} = 1;
} elsif ($prev->{fsType} ne $new->{fsType} || $prev->{device} ne $new->{device}) {
# Filesystem type or device changed, so unmount and mount it.
$unitsToStop{$unit} = 1;
$unitsToStart{$unit} = 1;
recordUnit($startListFile, $unit);
} elsif ($prev->{options} ne $new->{options}) {
# Mount options changes, so remount it.
$unitsToReload{$unit} = 1;
recordUnit($reloadListFile, $unit);
}
}
# Also handles swap devices.
foreach my $device (keys %$prevSwaps) {
my $prev = $prevSwaps->{$device};
my $new = $newSwaps->{$device};
if (!defined $new) {
# Swap entry disappeared, so turn it off. Can't use
# "systemctl stop" here because systemd has lots of alias
# units that prevent a stop from actually calling
# "swapoff".
print STDERR "stopping swap device: $device\n";
system("@utillinux@/sbin/swapoff", $device);
}
# FIXME: update swap options (i.e. its priority).
}
# Should we have systemd re-exec itself?
my $prevSystemd = abs_path("/proc/1/exe") // "/unknown";
my $newSystemd = abs_path("@systemd@/lib/systemd/systemd") or die;
my $restartSystemd = $prevSystemd ne $newSystemd;
sub filterUnits {
my ($units) = @_;
my @res;
foreach my $unit (sort(keys %{$units})) {
push @res, $unit if !defined $unitsToFilter{$unit};
}
return @res;
}
my @unitsToStopFiltered = filterUnits(\%unitsToStop);
my @unitsToStartFiltered = filterUnits(\%unitsToStart);
# Show dry-run actions.
if ($action eq "dry-activate") {
print STDERR "would stop the following units: ", join(", ", @unitsToStopFiltered), "\n"
if scalar @unitsToStopFiltered > 0;
print STDERR "would NOT stop the following changed units: ", join(", ", sort(keys %unitsToSkip)), "\n"
if scalar(keys %unitsToSkip) > 0;
print STDERR "would restart systemd\n" if $restartSystemd;
print STDERR "would restart the following units: ", join(", ", sort(keys %unitsToRestart)), "\n"
if scalar(keys %unitsToRestart) > 0;
print STDERR "would start the following units: ", join(", ", @unitsToStartFiltered), "\n"
if scalar @unitsToStartFiltered;
print STDERR "would reload the following units: ", join(", ", sort(keys %unitsToReload)), "\n"
if scalar(keys %unitsToReload) > 0;
exit 0;
}
syslog(LOG_NOTICE, "switching to system configuration $out");
if (scalar (keys %unitsToStop) > 0) {
print STDERR "stopping the following units: ", join(", ", @unitsToStopFiltered), "\n"
if scalar @unitsToStopFiltered;
# Use current version of systemctl binary before daemon is reexeced.
system("/run/current-system/sw/bin/systemctl", "stop", "--", sort(keys %unitsToStop)); # FIXME: ignore errors?
}
print STDERR "NOT restarting the following changed units: ", join(", ", sort(keys %unitsToSkip)), "\n"
if scalar(keys %unitsToSkip) > 0;
# Activate the new configuration (i.e., update /etc, make accounts,
# and so on).
my $res = 0;
print STDERR "activating the configuration...\n";
system("$out/activate", "$out") == 0 or $res = 2;
# Restart systemd if necessary.
if ($restartSystemd) {
print STDERR "restarting systemd...\n";
system("@systemd@/bin/systemctl", "daemon-reexec") == 0 or $res = 2;
}
# Forget about previously failed services.
system("@systemd@/bin/systemctl", "reset-failed");
# Make systemd reload its units.
system("@systemd@/bin/systemctl", "daemon-reload") == 0 or $res = 3;
# Reload user units
open my $listActiveUsers, '-|', '@systemd@/bin/loginctl', 'list-users', '--no-legend';
while (my $f = <$listActiveUsers>) {
next unless $f =~ /^\s*(?<uid>\d+)\s+(?<user>\S+)/;
my ($uid, $name) = ($+{uid}, $+{user});
print STDERR "reloading user units for $name...\n";
system("@su@", "-s", "@shell@", "-l", $name, "-c", "XDG_RUNTIME_DIR=/run/user/$uid @systemd@/bin/systemctl --user daemon-reload");
system("@su@", "-s", "@shell@", "-l", $name, "-c", "XDG_RUNTIME_DIR=/run/user/$uid @systemd@/bin/systemctl --user start nixos-activation.service");
}
close $listActiveUsers;
# Set the new tmpfiles
print STDERR "setting up tmpfiles\n";
system("@systemd@/bin/systemd-tmpfiles", "--create", "--remove", "--exclude-prefix=/dev") == 0 or $res = 3;
# Reload units that need it. This includes remounting changed mount
# units.
if (scalar(keys %unitsToReload) > 0) {
print STDERR "reloading the following units: ", join(", ", sort(keys %unitsToReload)), "\n";
system("@systemd@/bin/systemctl", "reload", "--", sort(keys %unitsToReload)) == 0 or $res = 4;
unlink($reloadListFile);
}
# Restart changed services (those that have to be restarted rather
# than stopped and started).
if (scalar(keys %unitsToRestart) > 0) {
print STDERR "restarting the following units: ", join(", ", sort(keys %unitsToRestart)), "\n";
system("@systemd@/bin/systemctl", "restart", "--", sort(keys %unitsToRestart)) == 0 or $res = 4;
unlink($restartListFile);
}
# Start all active targets, as well as changed units we stopped above.
# The latter is necessary because some may not be dependencies of the
# targets (i.e., they were manually started). FIXME: detect units
# that are symlinks to other units. We shouldn't start both at the
# same time because we'll get a "Failed to add path to set" error from
# systemd.
print STDERR "starting the following units: ", join(", ", @unitsToStartFiltered), "\n"
if scalar @unitsToStartFiltered;
system("@systemd@/bin/systemctl", "start", "--", sort(keys %unitsToStart)) == 0 or $res = 4;
unlink($startListFile);
# Print failed and new units.
my (@failed, @new, @restarting);
my $activeNew = getActiveUnits;
while (my ($unit, $state) = each %{$activeNew}) {
if ($state->{state} eq "failed") {
push @failed, $unit;
}
elsif ($state->{state} eq "auto-restart") {
# A unit in auto-restart state is a failure *if* it previously failed to start
my $lines = `@systemd@/bin/systemctl show '$unit'`;
my $info = {};
parseKeyValues($info, split("\n", $lines));
if ($info->{ExecMainStatus} ne '0') {
push @failed, $unit;
}
}
elsif ($state->{state} ne "failed" && !defined $activePrev->{$unit}) {
push @new, $unit;
}
}
print STDERR "the following new units were started: ", join(", ", sort(@new)), "\n"
if scalar @new > 0;
if (scalar @failed > 0) {
print STDERR "warning: the following units failed: ", join(", ", sort(@failed)), "\n";
foreach my $unit (@failed) {
print STDERR "\n";
system("COLUMNS=1000 @systemd@/bin/systemctl status --no-pager '$unit' >&2");
}
$res = 4;
}
if ($res == 0) {
syslog(LOG_NOTICE, "finished switching to system configuration $out");
} else {
syslog(LOG_ERR, "switching to system configuration $out failed (status $res)");
}
exit $res;
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