From 30a6122f8061e8c3ac2d96078b75aafa63101f02 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 9 Apr 2003 12:46:44 +0000 Subject: [PATCH] * When we activate a descriptor in nix-switch, remember its hash. This allows us to find out all `live' packages on the system by doing nix closure $(cat /nix/var/nix/links/*.hash) which will print out the activated configurations and all packages referenced by them. We could then garbage collect unused packages by deleting the difference between `nix listinst' and the set returned by `nix closure ...'. --- scripts/nix-switch | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/scripts/nix-switch b/scripts/nix-switch index 74bcef8566..aec61cbfe1 100755 --- a/scripts/nix-switch +++ b/scripts/nix-switch @@ -20,11 +20,17 @@ chomp $id; my $nr = 0; while (-e "$linkdir/$id-$nr") { $nr++; } my $link = "$linkdir/$id-$nr"; -print "$pkgdir\n"; # Create a symlink from $link to $pkgdir. symlink($pkgdir, $link) or die "cannot create $link"; +# Also store the hash of $pkgdir. This is useful for garbage +# collection and the like. +my $hashfile = "$linkdir/$id-$nr.hash"; +open HASH, "> $hashfile" or die "cannot create $hashfile"; +print HASH "$hash\n"; +close HASH; + # 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