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switch-to-configuration: Handle changes to fileSystems

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We now automatically remount filesystems with changed options, mount
new filesystems, and unmount obsolete filesystems.
This commit is contained in:
Eelco Dolstra 2012-08-10 10:56:55 -04:00
parent 52b6e10315
commit ce7ead7bd7
1 changed files with 87 additions and 21 deletions
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96
modules/system/activation/switch-to-configuration.pl
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@ -7,6 +7,7 @@ use File::Slurp;
use Cwd 'abs_path';
my $restartListFile = "/run/systemd/restart-list";
my $reloadListFile = "/run/systemd/reload-list";
my $action = shift @ARGV;
@ -61,6 +62,19 @@ sub getActiveUnits {
return $res;
}
sub parseFstab {
my ($filename) = @_;
my %res;
foreach my $line (read_file($filename, err_mode => 'quiet')) {
chomp $line;
$line =~ s/#.*//;
next if $line =~ /^\s*$/;
my @xs = split / /, $line;
$res{$xs[1]} = { device => $xs[0], fsType => $xs[2], options => $xs[3] };
}
return %res;
}
# Forget about previously failed services.
system("@systemd@/bin/systemctl", "reset-failed");
@ -73,11 +87,17 @@ while (my ($unit, $state) = each %{$activePrev}) {
# Recognise template instances.
$baseUnit = "$1\@.$2" if $unit =~ /^(.*)@[^\.]*\.(.*)$/;
my $prevUnitFile = "/etc/systemd/system/$baseUnit";
if (-e $prevUnitFile && ($state->{state} eq "active" || $state->{state} eq "activating")) {
my $newUnitFile = "@out@/etc/systemd/system/$baseUnit";
if (-e $prevUnitFile && ($state->{state} eq "active" || $state->{state} eq "activating")) {
if (! -e $newUnitFile) {
push @unitsToStop, $unit;
} elsif (abs_path($prevUnitFile) ne abs_path($newUnitFile)) {
if ($unit =~ /\.target$/) {
write_file($restartListFile, { append => 1 }, "$unit\n");
} elsif ($unit =~ /\.mount$/) {
# Reload the changed mount unit to force a remount.
write_file($reloadListFile, { append => 1 }, "$unit\n");
} else {
# Record that this unit needs to be started below. We
# write this to a file to ensure that the service gets
# restarted if we're interrupted.
@ -85,11 +105,46 @@ while (my ($unit, $state) = each %{$activePrev}) {
push @unitsToStop, $unit;
}
}
}
}
sub pathToUnitName {
my ($path) = @_;
die unless substr($path, 0, 1) eq "/";
return "-" if $path eq "/";
$path = substr($path, 1);
$path =~ s/\//-/g;
# FIXME: handle - and unprintable characters.
return $path;
}
# 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 %prevFstab = parseFstab "/etc/fstab";
my %newFstab = parseFstab "@out@/etc/fstab";
foreach my $mountPoint (keys %prevFstab) {
my $prev = $prevFstab{$mountPoint};
my $new = $newFstab{$mountPoint};
my $unit = pathToUnitName($mountPoint). ".mount";
if (!defined $new) {
# Entry disappeared, so unmount it.
push @unitsToStop, $unit;
} elsif ($prev->{fsType} ne $new->{fsType} || $prev->{device} ne $new->{device}) {
# Filesystem type or device changed, so unmount and mount it.
write_file($restartListFile, { append => 1 }, "$unit\n");
push @unitsToStop, $unit;
} elsif ($prev->{options} ne $new->{options}) {
# Mount options changes, so remount it.
write_file($reloadListFile, { append => 1 }, "$unit\n");
}
}
if (scalar @unitsToStop > 0) {
print STDERR "stopping the following units: ", join(", ", sort(@unitsToStop)), "\n";
system("@systemd@/bin/systemctl", "stop", @unitsToStop); # FIXME: ignore errors?
system("@systemd@/bin/systemctl", "stop", "--", @unitsToStop); # FIXME: ignore errors?
}
# Activate the new configuration (i.e., update /etc, make accounts,
@ -103,21 +158,32 @@ system("@out@/activate", "@out@") == 0 or $res = 2;
# Make systemd reload its units.
system("@systemd@/bin/systemctl", "daemon-reload") == 0 or $res = 3;
# Start all units required by the default target. This should start
# most changed units we stopped above as well as any new dependencies.
print STDERR "starting default target...\n";
system("@systemd@/bin/systemctl", "start", "default.target") == 0 or $res = 4;
sub unique {
my %unique = map { $_, 1 } @_;
return sort(keys(%unique));
}
# Start changed units we stopped above. This is necessary because
# some may not be dependencies of the default target (i.e., they were
# Start the following units:
# - The default target. This should start most changed units we
# stopped above as well as any new dependencies.
# - local-fs.target. This mounts any missing local filesystems.
# - Changed units we stopped above. This is necessary because some
# may not be dependencies of the default target (i.e., they were
# manually started).
my @stopped = split '\n', read_file($restartListFile, err_mode => 'quiet') // "";
if (scalar @stopped > 0) {
my %unique = map { $_, 1 } @stopped;
my @unique = sort(keys(%unique));
print STDERR "restarting the following units: ", join(", ", @unique), "\n";
system("@systemd@/bin/systemctl", "start", @unique) == 0 or $res = 4;
unlink($restartListFile);
my @start = unique(
"default.target", "local-fs.target",
split('\n', read_file($restartListFile, err_mode => 'quiet') // ""));
print STDERR "starting the following units: ", join(", ", @start), "\n";
system("@systemd@/bin/systemctl", "start", "--", @start) == 0 or $res = 4;
unlink($restartListFile);
# Reload units that need it. This includes remounting changed mount
# units.
my @reload = unique(split '\n', read_file($reloadListFile, err_mode => 'quiet') // "");
if (scalar @reload > 0) {
print STDERR "reloading the following units: ", join(", ", @reload), "\n";
system("@systemd@/bin/systemctl", "reload", "--", @reload) == 0 or $res = 4;
unlink($reloadListFile);
}
# Signal dbus to reload its configuration.