Author: eelco
Date: Mon Sep 13 17:26:42 2010
New Revision: 23766
URL: https://svn.nixos.org/websvn/nix/?rev=23766&sc=1
Log:
* Speed up the initialisation of /etc in the activation script a lot
by doing it in Perl instead of in Bash. Forking a zillion times is
slow.
Added:
nixos/trunk/modules/system/etc/setup-etc.pl
Modified:
nixos/trunk/modules/system/etc/etc.nix
Modified: nixos/trunk/modules/system/etc/etc.nix
==============================================================================
--- nixos/trunk/modules/system/etc/etc.nix Mon Sep 13 16:06:07 2010
(r23765)
+++ nixos/trunk/modules/system/etc/etc.nix Mon Sep 13 17:26:42 2010
(r23766)
@@ -37,7 +37,7 @@
chmod ${mode} "$target"
'';
- makeEtc = pkgs.stdenv.mkDerivation {
+ etc = pkgs.stdenv.mkDerivation {
name = "etc";
builder = ./make-etc.sh;
@@ -53,39 +53,13 @@
{
require = [option];
- system.build.etc = makeEtc;
+ system.build.etc = etc;
system.activationScripts.etc = stringAfter [ "systemConfig" "stdio" ]
''
# Set up the statically computed bits of /etc.
echo "setting up /etc..."
- staticEtc=/etc/static
- rm -f $staticEtc
- ln -s ${makeEtc}/etc $staticEtc
- for i in $(cd $staticEtc && find * -type l); do
- mkdir -p /etc/$(dirname $i)
- rm -f /etc/$i
- if test -e "$staticEtc/$i.mode"; then
- # Create a regular file in /etc.
- cp $staticEtc/$i /etc/$i
- chown 0.0 /etc/$i
- chmod "$(cat "$staticEtc/$i.mode")" /etc/$i
- else
- # Create a symlink in /etc.
- ln -s $staticEtc/$i /etc/$i
- fi
- done
-
- # 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).
- for i in $(find /etc/ \( -path /etc/nixos -prune \) -o -type l); do
- target=$(readlink "$i")
- if test "''${target:0:''${#staticEtc}}" = "$staticEtc" -a ! -e "$i";
then
- rm -f "$i"
- fi
- done
+ ${pkgs.perl}/bin/perl ${./setup-etc.pl} ${etc}/etc
'';
}
Added: nixos/trunk/modules/system/etc/setup-etc.pl
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ nixos/trunk/modules/system/etc/setup-etc.pl Mon Sep 13 17:26:42 2010
(r23766)
@@ -0,0 +1,65 @@
+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;
+
+
+# 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 $mode;
+ close MODE;
+ copy "$static/$fn", "$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, $etc);
+
+
+# Remove dangling symlinks that point to /etc/static. These are
+# configuration files that existed in a previous configuration but not
+# in the current one. For efficiency, don't look under /etc/nixos
+# (where all the NixOS sources live).
+sub cleanup {
+ if ($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/");
+ unlink "$_" unless -e "$x";
+ }
+ }
+}
+
+find(\&cleanup, "/etc");
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