ADD: User authentication

* User Authentication Implementation
* Rename file to conform to fileformat `sqlite3_*_omit.go`
* Updated sqlite3-binding.* with new upgrade tool
* Add: callbackRetNil required for error type return because of adding `RegisterFunc`s directly on the connection.
* Add: TestCreateAuthDatabase

sqlite3_opt_userauth.go

@@ -0,0 +1,127 @@
+// Copyright (C) 2018 G.J.R. Timmer <gjr.timmer@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build sqlite_userauth
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -DSQLITE_USER_AUTHENTICATION
+#cgo LDFLAGS: -lm
+#ifndef USE_LIBSQLITE3
+#include <sqlite3-binding.h>
+#else
+#include <sqlite3.h>
+#endif
+#include <stdlib.h>
+
+static int
+_sqlite3_user_authenticate(sqlite3* db, const char* zUsername, const char* aPW, int nPW)
+{
+  return sqlite3_user_authenticate(db, zUsername, aPW, nPW);
+}
+
+static int
+_sqlite3_user_add(sqlite3* db, const char* zUsername, const char* aPW, int nPW, int isAdmin)
+{
+  return sqlite3_user_add(db, zUsername, aPW, nPW, isAdmin);
+}
+
+static int
+_sqlite3_user_change(sqlite3* db, const char* zUsername, const char* aPW, int nPW, int isAdmin)
+{
+  return sqlite3_user_change(db, zUsername, aPW, nPW, isAdmin);
+}
+
+static int
+_sqlite3_user_delete(sqlite3* db, const char* zUsername)
+{
+  return sqlite3_user_delete(db, zUsername);
+}
+*/
+import "C"
+
+const (
+	SQLITE_AUTH = C.SQLITE_AUTH
+)
+
+// Authenticate will perform an authentication of the provided username
+// and password against the database.
+//
+// If a database contains the SQLITE_USER table, then the
+// call to Authenticate must be invoked with an
+// appropriate username and password prior to enable read and write
+//access to the database.
+//
+// Return SQLITE_OK on success or SQLITE_ERROR if the username/password
+// combination is incorrect or unknown.
+//
+// If the SQLITE_USER table is not present in the database file, then
+// this interface is a harmless no-op returnning SQLITE_OK.
+func (c *SQLiteConn) Authenticate(username, password string) error {
+	rv := C._sqlite3_user_authenticate(c.db, C.CString(username), C.CString(password), C.int(len(password)))
+	if rv != C.SQLITE_OK {
+		return c.lastError()
+	}
+
+	return nil
+}
+
+// AuthUserAdd can be used (by an admin user only)
+// to create a new user. When called on a no-authentication-required
+// database, this routine converts the database into an authentication-
+// required database, automatically makes the added user an
+// administrator, and logs in the current connection as that user.
+// The AuthUserAdd only works for the "main" database, not
+// for any ATTACH-ed databases. Any call to AuthUserAdd by a
+// non-admin user results in an error.
+func (c *SQLiteConn) AuthUserAdd(username, password string, admin bool) error {
+	isAdmin := 0
+	if admin {
+		isAdmin = 1
+	}
+
+	rv := C._sqlite3_user_add(c.db, C.CString(username), C.CString(password), C.int(len(password)), C.int(isAdmin))
+	if rv != C.SQLITE_OK {
+		return c.lastError()
+	}
+
+	return nil
+}
+
+// AuthUserChange can be used to change a users
+// login credentials or admin privilege.  Any user can change their own
+// login credentials. Only an admin user can change another users login
+// credentials or admin privilege setting. No user may change their own
+// admin privilege setting.
+func (c *SQLiteConn) AuthUserChange(username, password string, admin bool) error {
+	isAdmin := 0
+	if admin {
+		isAdmin = 1
+	}
+
+	rv := C._sqlite3_user_change(c.db, C.CString(username), C.CString(password), C.int(len(password)), C.int(isAdmin))
+	if rv != C.SQLITE_OK {
+		return c.lastError()
+	}
+
+	return nil
+}
+
+// AuthUserDelete can be used (by an admin user only)
+// to delete a user. The currently logged-in user cannot be deleted,
+// which guarantees that there is always an admin user and hence that
+// the database cannot be converted into a no-authentication-required
+// database.
+func (c *SQLiteConn) AuthUserDelete(username string) error {
+	rv := C._sqlite3_user_delete(c.db, C.CString(username))
+	if rv != C.SQLITE_OK {
+		return c.lastError()
+	}
+
+	return nil
+}
+
+// EOF