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