398 lines
15 KiB
Perl
398 lines
15 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 Sys::Syslog qw(:standard :macros);
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use Cwd 'abs_path';
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my $out = "@out@";
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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: $0 [switch|boot|test]
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switch: make the configuration the boot default and activate now
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boot: make the configuration the boot default
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test: activate the configuration, but don\'t make it the boot default
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EOF
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exit 1;
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}
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# This is a NixOS installation if it has /etc/NIXOS or a proper
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# /etc/os-release.
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die "This is not a NixOS installation!\n" unless
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-f "/etc/NIXOS" || (read_file("/etc/os-release", err_mode => 'quiet') // "") =~ /ID=nixos/s;
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openlog("nixos", "", LOG_USER);
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# Install or update the bootloader.
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if ($action eq "switch" || $action eq "boot") {
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system("@installBootLoader@ $out") == 0 or exit 1;
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}
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# Just in case the new configuration hangs the system, do a sync now.
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system("@coreutils@/bin/sync") unless ($ENV{"NIXOS_NO_SYNC"} // "") eq "1";
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exit 0 if $action eq "boot";
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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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syslog(LOG_NOTICE, "switching to system configuration $out");
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# Ignore SIGHUP so that we're not killed if we're running on (say)
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# virtual console 1 and we restart the "tty1" unit.
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$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 = `LANG= systemctl list-units --full --no-legend`;
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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/^\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 $info = {};
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parseKeyValues($info, read_file($filename));
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parseKeyValues($info, read_file("${filename}.d/overrides.conf")) if -f "${filename}.d/overrides.conf";
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return $info;
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}
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sub parseKeyValues {
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my $info = shift;
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foreach my $line (@_) {
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# FIXME: not quite correct.
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$line =~ /^([^=]+)=(.*)$/ or next;
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$info->{$1} = $2;
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}
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}
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sub boolIsTrue {
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my ($s) = @_;
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return $s eq "yes" || $s eq "true";
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}
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# As a fingerprint for determining whether a unit has changed, we use
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# its absolute path. If it has an override file, we append *its*
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# absolute path as well.
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sub fingerprintUnit {
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my ($s) = @_;
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return abs_path($s) . (-f "${s}.d/overrides.conf" ? " " . abs_path "${s}.d/overrides.conf" : "");
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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 $newUnitFile || abs_path($newUnitFile) eq "/dev/null") {
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push @unitsToStop, $unit;
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}
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elsif ($unit =~ /\.target$/) {
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my $unitInfo = parseUnit($newUnitFile);
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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" && $unit ne "hybrid-sleep.target") {
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unless (boolIsTrue($unitInfo->{'RefuseManualStart'} // "no")) {
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write_file($startListFile, { append => 1 }, "$unit\n");
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}
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}
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# Stop targets that have X-StopOnReconfiguration set.
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# This is necessary to respect dependency orderings
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# involving targets: if unit X starts after target Y and
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# target Y starts after unit Z, then if X and Z have both
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# changed, then X should be restarted after Z. However,
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# if target Y is in the "active" state, X and Z will be
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# restarted at the same time because X's dependency on Y
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# is already satisfied. Thus, we need to stop Y first.
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# Stopping a target generally has no effect on other units
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# (unless there is a PartOf dependency), so this is just a
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# bookkeeping thing to get systemd to do the right thing.
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if (boolIsTrue($unitInfo->{'X-StopOnReconfiguration'} // "no")) {
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push @unitsToStop, $unit;
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}
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}
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elsif (fingerprintUnit($prevUnitFile) ne fingerprintUnit($newUnitFile)) {
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if ($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($unitInfo->{'X-ReloadIfChanged'} // "no")) {
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write_file($reloadListFile, { append => 1 }, "$unit\n");
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}
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elsif (!boolIsTrue($unitInfo->{'X-RestartIfChanged'} // "yes") || boolIsTrue($unitInfo->{'RefuseManualStop'} // "no") ) {
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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($unitInfo->{'X-StopIfChanged'} // "yes")) {
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# This unit should be restarted instead of
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# stopped and started.
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write_file($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("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 $res = 3;
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# Signal dbus to reload its configuration before starting other units.
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# Other units may rely on newly installed policy files under /etc/dbus-1
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system("@systemd@/bin/systemctl", "reload", "dbus.service");
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# Restart changed services (those that have to be restarted rather
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# than stopped and started).
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my @restart = unique(split('\n', read_file($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", "timers.target", "sockets.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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# 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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if ($state->{state} eq "failed") {
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push @failed, $unit;
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}
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elsif ($state->{state} eq "auto-restart") {
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# A unit in auto-restart state is a failure *if* it previously failed to start
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my $lines = `@systemd@/bin/systemctl show '$unit'`;
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my $info = {};
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parseKeyValues($info, split("\n", $lines));
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if ($info->{ExecMainStatus} ne '0') {
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push @failed, $unit;
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}
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}
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elsif ($state->{state} ne "failed" && !defined $activePrev->{$unit}) {
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push @new, $unit;
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}
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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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$res = 4;
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}
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if ($res == 0) {
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syslog(LOG_NOTICE, "finished switching to system configuration $out");
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} else {
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syslog(LOG_ERR, "switching to system configuration $out failed (status $res)");
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}
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exit $res;
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