forked from mirrors/nixpkgs
81 lines
2.3 KiB
Perl
81 lines
2.3 KiB
Perl
use strict;
|
||
use File::Find;
|
||
use File::Copy;
|
||
use File::Path;
|
||
use File::Basename;
|
||
|
||
my $etc = $ARGV[0] or die;
|
||
my $static = "/etc/static";
|
||
|
||
sub atomicSymlink {
|
||
my ($source, $target) = @_;
|
||
my $tmp = "$target.tmp";
|
||
unlink $tmp;
|
||
symlink $source, $tmp or return 1;
|
||
rename $tmp, $target or return 1;
|
||
return 1;
|
||
}
|
||
|
||
|
||
# Atomically update /etc/static to point at the etc files of the
|
||
# current configuration.
|
||
atomicSymlink $etc, $static or die;
|
||
|
||
|
||
# Remove dangling symlinks that point to /etc/static. These are
|
||
# configuration files that existed in a previous configuration but not
|
||
# in the current one. For efficiency, don't look under /etc/nixos
|
||
# (where all the NixOS sources live).
|
||
sub cleanup {
|
||
if ($File::Find::name eq "/etc/nixos") {
|
||
$File::Find::prune = 1;
|
||
return;
|
||
}
|
||
if (-l $_) {
|
||
my $target = readlink $_;
|
||
if (substr($target, 0, length $static) eq $static) {
|
||
my $x = "/etc/static/" . substr($File::Find::name, length "/etc/");
|
||
unless (-l $x) {
|
||
print STDERR "removing obsolete symlink ‘$File::Find::name’...\n";
|
||
unlink "$_";
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
find(\&cleanup, "/etc");
|
||
|
||
|
||
# For every file in the etc tree, create a corresponding symlink in
|
||
# /etc to /etc/static. The indirection through /etc/static is to make
|
||
# switching to a new configuration somewhat more atomic.
|
||
sub link {
|
||
my $fn = substr $File::Find::name, length($etc) + 1 or next;
|
||
my $target = "/etc/$fn";
|
||
File::Path::make_path(dirname $target);
|
||
if (-e "$_.mode") {
|
||
open MODE, "<$_.mode";
|
||
my $mode = <MODE>; chomp $mode;
|
||
close MODE;
|
||
if ($mode eq "direct-symlink") {
|
||
atomicSymlink readlink("$static/$fn"), $target or warn;
|
||
} else {
|
||
open UID, "<$_.uid";
|
||
my $uid = <UID>; chomp $uid;
|
||
close UID;
|
||
open GID, "<$_.gid";
|
||
my $gid = <GID>; chomp $gid;
|
||
close GID;
|
||
|
||
copy "$static/$fn", "$target.tmp" or warn;
|
||
chown int($uid), int($gid), "$target.tmp" or warn;
|
||
chmod oct($mode), "$target.tmp" or warn;
|
||
rename "$target.tmp", $target or warn;
|
||
}
|
||
} elsif (-l "$_") {
|
||
atomicSymlink "$static/$fn", $target or warn;
|
||
}
|
||
}
|
||
|
||
find(\&link, $etc);
|