py/builtinimport: Fix crash handling "weak link" module names.

There are two calls to mp_builtin___import__():
1. ports/unix/main.c:main_() which provides a str in args[0]
2. py/runtime.c:mp_import_name() which provides a qstr in args[0]

The default implementation of mp_builtin___import__() is
mp_builtin___import___default() which has a different implementation based
on MICROPY_ENABLE_EXTERNAL_IMPORT.

If MICROPY_ENABLE_EXTERNAL_IMPORT is disabled then the handling of weak
links assumes that args[0] is a `const char *`, when it is either a str or
qstr object.

Use the existing qstr of the module name instead, and also use a vstr
instead of strcpy() to ensure no overflow occurs.

0 files changed, 0 insertions, 0 deletions