Allow substituters to be marked as trusted

This is needed by nixos-install, which uses the Nix store on the
installation CD as a substituter. We don't want to disable signature
checking entirely because substitutes from cache.nixos.org should
still be checked. So now we can pas "local?trusted=1" to mark only the
Nix store in /nix as not requiring signatures.

Fixes #1819.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 70f23e1fcaf4..aa83c2ded8c8 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -248,6 +248,8 @@ public:
 
     const Setting<int> pathInfoCacheSize{this, 65536, "path-info-cache-size", "size of the in-memory store path information cache"};
 
+    const Setting<bool> isTrusted{this, false, "trusted", "whether paths from this store can be used as substitutes even when they lack trusted signatures"};
+
 protected:
 
     struct State