mirror of
https://github.com/NixOS/nixpkgs.git
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96ba0ca283
During a configuration switch, changed units are stopped in the old
configuration, then started in the new configuration (i.e. after
running the activation script and running "systemctl daemon-reload").
This ensures that services are stopped using the ExecStop/ExecStopPost
commands from the old configuration.
However, for some services it's undesirable to stop them; in
particular dhcpcd, which deconfigures its network interfaces when it
stops. This is dangerous when doing remote upgrades - usually things
go right (especially because the switch script ignores SIGHUP), but
not always (see 9aa69885f0). Likewise,
sshd should be kept running for as long as possible to prevent a
lock-out if the switch fails.
So the new option ‘stopIfChanged = false’ causes "systemctl restart"
to be used instead of "systemctl stop" followed by "systemctl start".
This is only proper for services that don't have stop commands. (And
it might not handle dependencies properly in some cases, but I'm not
sure.)
333 lines
12 KiB
Perl
333 lines
12 KiB
Perl
#! @perl@
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use strict;
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use warnings;
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use File::Basename;
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use File::Slurp;
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use Cwd 'abs_path';
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my $startListFile = "/run/systemd/start-list";
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my $restartListFile = "/run/systemd/restart-list";
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my $reloadListFile = "/run/systemd/reload-list";
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my $action = shift @ARGV;
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if (!defined $action || ($action ne "switch" && $action ne "boot" && $action ne "test")) {
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print STDERR <<EOF;
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Usage: $0 [switch|boot|test]
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switch: make the configuration the boot default and activate now
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boot: make the configuration the boot default
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test: activate the configuration, but don\'t make it the boot default
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EOF
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exit 1;
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}
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die "This is not a NixOS installation (/etc/NIXOS is missing)!\n" unless -f "/etc/NIXOS";
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# Install or update the bootloader.
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if ($action eq "switch" || $action eq "boot") {
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system("@installBootLoader@ @out@") == 0 or exit 1;
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exit 0 if $action eq "boot";
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}
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# Check if we can activate the new configuration.
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my $oldVersion = read_file("/run/current-system/init-interface-version", err_mode => 'quiet') // "";
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my $newVersion = read_file("@out@/init-interface-version");
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if ($newVersion ne $oldVersion) {
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print STDERR <<EOF;
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Warning: the new NixOS configuration has an ‘init’ that is
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incompatible with the current configuration. The new configuration
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won\'t take effect until you reboot the system.
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EOF
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exit 100;
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}
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# Ignore SIGHUP so that we're not killed if we're running on (say)
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# virtual console 1 and we restart the "tty1" unit.
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$SIG{PIPE} = "IGNORE";
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sub getActiveUnits {
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# FIXME: use D-Bus or whatever to query this, since parsing the
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# output of list-units is likely to break.
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my $lines = `@systemd@/bin/systemctl list-units --full`;
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my $res = {};
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foreach my $line (split '\n', $lines) {
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chomp $line;
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last if $line eq "";
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$line =~ /^(\S+)\s+(\S+)\s+(\S+)\s+(\S+)\s/ or next;
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next if $1 eq "UNIT";
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$res->{$1} = { load => $2, state => $3, substate => $4 };
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}
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return $res;
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}
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sub parseFstab {
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my ($filename) = @_;
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my ($fss, $swaps);
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foreach my $line (read_file($filename, err_mode => 'quiet')) {
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chomp $line;
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$line =~ s/#.*//;
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next if $line =~ /^\s*$/;
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my @xs = split / /, $line;
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if ($xs[2] eq "swap") {
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$swaps->{$xs[0]} = { options => $xs[3] // "" };
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} else {
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$fss->{$xs[1]} = { device => $xs[0], fsType => $xs[2], options => $xs[3] // "" };
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}
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}
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return ($fss, $swaps);
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}
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sub parseUnit {
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my ($filename) = @_;
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my $info = {};
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foreach my $line (read_file($filename)) {
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# FIXME: not quite correct.
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$line =~ /^([^=]+)=(.*)$/ or next;
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$info->{$1} = $2;
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}
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return $info;
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}
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sub boolIsTrue {
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my ($s) = @_;
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return $s eq "yes" || $s eq "true";
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}
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# Stop all services that no longer exist or have changed in the new
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# configuration.
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my (@unitsToStop, @unitsToSkip);
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my $activePrev = getActiveUnits;
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while (my ($unit, $state) = each %{$activePrev}) {
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my $baseUnit = $unit;
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# Recognise template instances.
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$baseUnit = "$1\@.$2" if $unit =~ /^(.*)@[^\.]*\.(.*)$/;
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my $prevUnitFile = "/etc/systemd/system/$baseUnit";
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my $newUnitFile = "@out@/etc/systemd/system/$baseUnit";
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my $baseName = $baseUnit;
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$baseName =~ s/\.[a-z]*$//;
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if (-e $prevUnitFile && ($state->{state} eq "active" || $state->{state} eq "activating")) {
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if (! -e $newUnitFile) {
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push @unitsToStop, $unit;
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}
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elsif ($unit =~ /\.target$/) {
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# Cause all active target units to be restarted below.
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# This should start most changed units we stop here as
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# well as any new dependencies (including new mounts and
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# swap devices). FIXME: the suspend target is sometimes
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# active after the system has resumed, which probably
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# should not be the case. Just ignore it.
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if ($unit ne "suspend.target" && $unit ne "hibernate.target") {
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my $unitInfo = parseUnit($newUnitFile);
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unless (boolIsTrue($unitInfo->{'RefuseManualStart'} // "false")) {
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write_file($startListFile, { append => 1 }, "$unit\n");
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}
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}
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}
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elsif (abs_path($prevUnitFile) ne abs_path($newUnitFile)) {
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if ($unit eq "sysinit.target" || $unit eq "basic.target" || $unit eq "multi-user.target" || $unit eq "graphical.target") {
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# Do nothing. These cannot be restarted directly.
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} elsif ($unit =~ /\.mount$/) {
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# Reload the changed mount unit to force a remount.
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write_file($reloadListFile, { append => 1 }, "$unit\n");
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} elsif ($unit =~ /\.socket$/ || $unit =~ /\.path$/) {
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# FIXME: do something?
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} else {
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my $unitInfo = parseUnit($newUnitFile);
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if (!boolIsTrue($unitInfo->{'X-RestartIfChanged'} // "true")
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|| $unit eq "systemd-user-sessions.service"
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|| $unit eq "systemd-journald.service")
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{
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push @unitsToSkip, $unit;
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} else {
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# If this unit is socket-activated, then stop the
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# socket unit(s) as well, and restart the
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# socket(s) instead of the service.
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my $socketActivated = 0;
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if ($unit =~ /\.service$/) {
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my @sockets = split / /, ($unitInfo->{Sockets} // "");
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if (scalar @sockets == 0) {
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@sockets = ("$baseName.socket");
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}
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foreach my $socket (@sockets) {
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if (defined $activePrev->{$socket}) {
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push @unitsToStop, $socket;
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write_file($startListFile, { append => 1 }, "$socket\n");
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$socketActivated = 1;
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}
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}
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}
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if (!boolIsTrue($unitInfo->{'X-StopIfChanged'} // "true")) {
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# This unit should be restarted instead of
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# stopped and started.
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write_file($restartListFile, { append => 1 }, "$unit\n");
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} else {
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# If the unit is not socket-activated, record
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# that this unit needs to be started below.
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# We write this to a file to ensure that the
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# service gets restarted if we're interrupted.
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if (!$socketActivated) {
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write_file($startListFile, { append => 1 }, "$unit\n");
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}
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push @unitsToStop, $unit;
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}
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}
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}
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}
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}
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}
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sub pathToUnitName {
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my ($path) = @_;
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die unless substr($path, 0, 1) eq "/";
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return "-" if $path eq "/";
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$path = substr($path, 1);
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$path =~ s/\//-/g;
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# FIXME: handle - and unprintable characters.
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return $path;
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}
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sub unique {
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my %seen;
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my @res;
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foreach my $name (@_) {
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next if $seen{$name};
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$seen{$name} = 1;
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push @res, $name;
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}
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return @res;
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}
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# Compare the previous and new fstab to figure out which filesystems
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# need a remount or need to be unmounted. New filesystems are mounted
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# automatically by starting local-fs.target. FIXME: might be nicer if
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# we generated units for all mounts; then we could unify this with the
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# unit checking code above.
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my ($prevFss, $prevSwaps) = parseFstab "/etc/fstab";
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my ($newFss, $newSwaps) = parseFstab "@out@/etc/fstab";
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foreach my $mountPoint (keys %$prevFss) {
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my $prev = $prevFss->{$mountPoint};
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my $new = $newFss->{$mountPoint};
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my $unit = pathToUnitName($mountPoint) . ".mount";
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if (!defined $new) {
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# Filesystem entry disappeared, so unmount it.
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push @unitsToStop, $unit;
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} elsif ($prev->{fsType} ne $new->{fsType} || $prev->{device} ne $new->{device}) {
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# Filesystem type or device changed, so unmount and mount it.
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write_file($startListFile, { append => 1 }, "$unit\n");
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push @unitsToStop, $unit;
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} elsif ($prev->{options} ne $new->{options}) {
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# Mount options changes, so remount it.
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write_file($reloadListFile, { append => 1 }, "$unit\n");
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}
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}
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# Also handles swap devices.
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foreach my $device (keys %$prevSwaps) {
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my $prev = $prevSwaps->{$device};
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my $new = $newSwaps->{$device};
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if (!defined $new) {
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# Swap entry disappeared, so turn it off. Can't use
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# "systemctl stop" here because systemd has lots of alias
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# units that prevent a stop from actually calling
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# "swapoff".
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print STDERR "stopping swap device: $device\n";
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system("@utillinux@/sbin/swapoff", $device);
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}
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# FIXME: update swap options (i.e. its priority).
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}
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if (scalar @unitsToStop > 0) {
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@unitsToStop = unique(@unitsToStop);
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print STDERR "stopping the following units: ", join(", ", sort(@unitsToStop)), "\n";
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system("@systemd@/bin/systemctl", "stop", "--", @unitsToStop); # FIXME: ignore errors?
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}
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print STDERR "NOT restarting the following units: ", join(", ", sort(@unitsToSkip)), "\n"
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if scalar @unitsToSkip > 0;
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# Activate the new configuration (i.e., update /etc, make accounts,
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# and so on).
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my $res = 0;
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print STDERR "activating the configuration...\n";
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system("@out@/activate", "@out@") == 0 or $res = 2;
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# Restart systemd if necessary.
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if (abs_path("/proc/1/exe") ne abs_path("@systemd@/lib/systemd/systemd")) {
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print STDERR "restarting systemd...\n";
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system("@systemd@/bin/systemctl", "daemon-reexec") == 0 or $res = 2;
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}
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# Forget about previously failed services.
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system("@systemd@/bin/systemctl", "reset-failed");
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# Make systemd reload its units.
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system("@systemd@/bin/systemctl", "daemon-reload") == 0 or $res = 3;
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# Restart changed services (those that have to be restarted rather
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# than stopped and started).
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my @restart = unique(split('\n', read_file($restartListFile, err_mode => 'quiet') // ""));
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if (scalar @restart > 0) {
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print STDERR "restarting the following units: ", join(", ", sort(@restart)), "\n";
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system("@systemd@/bin/systemctl", "restart", "--", @restart) == 0 or $res = 4;
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unlink($restartListFile);
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}
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# Start all active targets, as well as changed units we stopped above.
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# The latter is necessary because some may not be dependencies of the
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# targets (i.e., they were manually started). FIXME: detect units
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# that are symlinks to other units. We shouldn't start both at the
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# same time because we'll get a "Failed to add path to set" error from
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# systemd.
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my @start = unique("default.target", split('\n', read_file($startListFile, err_mode => 'quiet') // ""));
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print STDERR "starting the following units: ", join(", ", sort(@start)), "\n";
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system("@systemd@/bin/systemctl", "start", "--", @start) == 0 or $res = 4;
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unlink($startListFile);
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# Reload units that need it. This includes remounting changed mount
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# units.
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my @reload = unique(split '\n', read_file($reloadListFile, err_mode => 'quiet') // "");
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if (scalar @reload > 0) {
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print STDERR "reloading the following units: ", join(", ", sort(@reload)), "\n";
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system("@systemd@/bin/systemctl", "reload", "--", @reload) == 0 or $res = 4;
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unlink($reloadListFile);
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}
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# Signal dbus to reload its configuration.
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system("@systemd@/bin/systemctl", "reload", "dbus.service");
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# Print failed and new units.
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my (@failed, @new, @restarting);
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my $activeNew = getActiveUnits;
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while (my ($unit, $state) = each %{$activeNew}) {
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push @failed, $unit if $state->{state} eq "failed" || $state->{substate} eq "auto-restart";
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push @new, $unit if $state->{state} ne "failed" && !defined $activePrev->{$unit};
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}
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print STDERR "the following new units were started: ", join(", ", sort(@new)), "\n"
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if scalar @new > 0;
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if (scalar @failed > 0) {
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print STDERR "warning: the following units failed: ", join(", ", sort(@failed)), "\n";
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foreach my $unit (@failed) {
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print STDERR "\n";
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system("COLUMNS=1000 @systemd@/bin/systemctl status --no-pager '$unit' >&2");
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}
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$res = 4;
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}
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exit $res;
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