report actual error message if sqlite3_load_extension fails (#800)

* report actual error message if sqlite3_load_extension fails

* more fixes and test cases

Co-authored-by: Jesse Rittner <jrittner@lutron.com>

1 files changed, 26 insertions, 12 deletions

diff --git a/sqlite3_load_extension.go b/sqlite3_load_extension.go
index 23c5d31..e6c50f2 100644
--- a/sqlite3_load_extension.go
+++ b/sqlite3_load_extension.go
@@ -28,12 +28,9 @@ func (c *SQLiteConn) loadExtensions(extensions []string) error {
 	}
 
 	for _, extension := range extensions {
-		cext := C.CString(extension)
-		defer C.free(unsafe.Pointer(cext))
-		rv = C.sqlite3_load_extension(c.db, cext, nil, nil)
-		if rv != C.SQLITE_OK {
+		if err := c.loadExtension(extension, nil); err != nil {
 			C.sqlite3_enable_load_extension(c.db, 0)
-			return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
+			return err
 		}
 	}
 
@@ -41,6 +38,7 @@ func (c *SQLiteConn) loadExtensions(extensions []string) error {
 	if rv != C.SQLITE_OK {
 		return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
 	}
+
 	return nil
 }
 
@@ -51,19 +49,35 @@ func (c *SQLiteConn) LoadExtension(lib string, entry string) error {
 		return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
 	}
 
-	clib := C.CString(lib)
-	defer C.free(unsafe.Pointer(clib))
-	centry := C.CString(entry)
-	defer C.free(unsafe.Pointer(centry))
+	if err := c.loadExtension(lib, &entry); err != nil {
+		C.sqlite3_enable_load_extension(c.db, 0)
+		return err
+	}
 
-	rv = C.sqlite3_load_extension(c.db, clib, centry, nil)
+	rv = C.sqlite3_enable_load_extension(c.db, 0)
 	if rv != C.SQLITE_OK {
 		return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
 	}
 
-	rv = C.sqlite3_enable_load_extension(c.db, 0)
+	return nil
+}
+
+func (c *SQLiteConn) loadExtension(lib string, entry *string) error {
+	clib := C.CString(lib)
+	defer C.free(unsafe.Pointer(clib))
+
+	var centry *C.char
+	if entry != nil {
+		centry := C.CString(*entry)
+		defer C.free(unsafe.Pointer(centry))
+	}
+
+	var errMsg *C.char
+	defer C.sqlite3_free(unsafe.Pointer(errMsg))
+
+	rv := C.sqlite3_load_extension(c.db, clib, centry, &errMsg)
 	if rv != C.SQLITE_OK {
-		return errors.New(C.GoString(C.sqlite3_errmsg(c.db)))
+		return errors.New(C.GoString(errMsg))
 	}
 
 	return nil