diff options
| -rwxr-xr-x | scripts/nix-switch | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/scripts/nix-switch b/scripts/nix-switch index aec61cbfe147..8dea3856418b 100755 --- a/scripts/nix-switch +++ b/scripts/nix-switch @@ -1,6 +1,14 @@ #! /usr/bin/perl -w use strict; + +my $keep = 0; + +if (scalar @ARGV > 0 && $ARGV[0] eq "--keep") { + shift @ARGV; + $keep = 1; +} + my $hash = $ARGV[0]; $hash || die "no package hash specified"; @@ -31,6 +39,12 @@ open HASH, "> $hashfile" or die "cannot create $hashfile"; print HASH "$hash\n"; close HASH; +my $current = "$linkdir/current"; + +# Read the current generation so that we can delete it (if --keep +# wasn't specified). +my $oldlink = readlink($current); + # Make $link the current generation by pointing $linkdir/current to # it. The rename() system call is supposed to be essentially atomic # on Unix. That is, if we have links `current -> X' and `new_current @@ -39,10 +53,14 @@ close HASH; # condition. This is sufficient to atomically switch the current link # tree. -my $current = "$linkdir/current"; - print "switching $current to $link\n"; my $tmplink = "$linkdir/new_current"; symlink($link, $tmplink) or die "cannot create $tmplink"; rename($tmplink, $current) or die "cannot rename $tmplink"; + +if (!$keep && defined $oldlink) { + print "deleting old $oldlink\n"; + unlink $tmplink || print "cannot delete $tmplink"; + unlink "$tmplink.hash" || print "cannot delete $tmplink.hash"; +} |