1 files changed, 63 insertions, 0 deletions
diff --git a/src/mongo/gotools/common/auth/auth_info.go b/src/mongo/gotools/common/auth/auth_info.go
new file mode 100644
index 00000000000..a420770ebf2
--- /dev/null
+++ b/src/mongo/gotools/common/auth/auth_info.go
@@ -0,0 +1,63 @@
+// Package auth provides utilities for performing tasks related to authentication.
+package auth
+
+import (
+	"fmt"
+	"github.com/mongodb/mongo-tools/common/db"
+	"gopkg.in/mgo.v2/bson"
+	"strings"
+)
+
+// GetAuthVersion gets the authentication schema version of the connected server
+// and returns that value as an integer along with any error that occurred.
+func GetAuthVersion(commander db.CommandRunner) (int, error) {
+	results := bson.M{}
+	err := commander.Run(
+		bson.D{
+			{"getParameter", 1},
+			{"authSchemaVersion", 1},
+		},
+		&results,
+		"admin",
+	)
+
+	if err != nil {
+		errMessage := err.Error()
+		// as a necessary hack, if the error message takes a certain form,
+		// we can infer version 1. This is because early versions of mongodb
+		// had no concept of an "auth schema version", so asking for the
+		// authSchemaVersion value will return a "no option found" or "no such cmd"
+		if errMessage == "no option found to get" ||
+			strings.HasPrefix(errMessage, "no such cmd") {
+			return 1, nil
+		}
+		// otherwise it's a connection error, so bubble it up
+		return 0, err
+	}
+
+	version, ok := results["authSchemaVersion"].(int)
+	if !ok {
+		// very unlikely this will ever happen
+		return 0, fmt.Errorf(
+			"getParameter command returned non-numeric result: %v",
+			results["authSchemaVersion"])
+	}
+	return version, nil
+}
+
+// VerifySystemAuthVersion returns an error if authentication is not set up for
+// the given server.
+func VerifySystemAuthVersion(sessionProvider *db.SessionProvider) error {
+	session, err := sessionProvider.GetSession()
+	if err != nil {
+		return fmt.Errorf("error getting session from server: %v", err)
+	}
+	defer session.Close()
+	versionEntries := session.DB("admin").C("system.version")
+	if count, err := versionEntries.Count(); err != nil {
+		return fmt.Errorf("error checking pressence of auth version: %v", err)
+	} else if count == 0 {
+		return fmt.Errorf("found no auth version")
+	}
+	return nil
+}