nix verify-paths: Add ‘--sigs-needed <N>’ flag

This specifies the number of distinct signatures required to consider
each path "trusted".

Also renamed ‘--no-sigs’ to ‘--no-trust’ for the flag that disables
verifying whether a path is trusted (since a path can also be trusted
if it has no signatures, but was built locally).

2 files changed, 10 insertions, 1 deletions

diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index b9939feda..cc91ed287 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -333,12 +333,18 @@ unsigned int ValidPathInfo::checkSignatures(const PublicKeys & publicKeys) const
 {
     unsigned int good = 0;
     for (auto & sig : sigs)
-        if (verifyDetached(fingerprint(), sig, publicKeys))
+        if (checkSignature(publicKeys, sig))
             good++;
     return good;
 }
 
 
+bool ValidPathInfo::checkSignature(const PublicKeys & publicKeys, const std::string & sig) const
+{
+    return verifyDetached(fingerprint(), sig, publicKeys);
+}
+
+
 }
 
 
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 4ea360b9d..798054d16 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -127,6 +127,9 @@ struct ValidPathInfo
     /* Return the number of signatures on this .narinfo that were
        produced by one of the specified keys. */
     unsigned int checkSignatures(const PublicKeys & publicKeys) const;
+
+    /* Verify a single signature. */
+    bool checkSignature(const PublicKeys & publicKeys, const std::string & sig) const;
 };
 
 typedef list<ValidPathInfo> ValidPathInfos;