diff options
Diffstat (limited to 'py/objstringio.c')
| -rw-r--r-- | py/objstringio.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/py/objstringio.c b/py/objstringio.c index 645c441cb2..61da0203e1 100644 --- a/py/objstringio.c +++ b/py/objstringio.c @@ -1,5 +1,5 @@ /* - * This file is part of the Micro Python project, http://micropython.org/ + * This file is part of the MicroPython project, http://micropython.org/ * * The MIT License (MIT) * @@ -118,15 +118,28 @@ STATIC mp_uint_t stringio_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, struct mp_stream_seek_t *s = (struct mp_stream_seek_t*)arg; mp_uint_t ref = 0; switch (s->whence) { - case 1: // SEEK_CUR + case MP_SEEK_CUR: ref = o->pos; break; - case 2: // SEEK_END + case MP_SEEK_END: ref = o->vstr->len; break; } - o->pos = ref + s->offset; - s->offset = o->pos; + mp_uint_t new_pos = ref + s->offset; + + // For MP_SEEK_SET, offset is unsigned + if (s->whence != MP_SEEK_SET && s->offset < 0) { + if (new_pos > ref) { + // Negative offset from SEEK_CUR or SEEK_END went past 0. + // CPython sets position to 0, POSIX returns an EINVAL error + new_pos = 0; + } + } else if (new_pos < ref) { + // positive offset went beyond the limit of mp_uint_t + *errcode = MP_EINVAL; // replace with MP_EOVERFLOW when defined + return MP_STREAM_ERROR; + } + s->offset = o->pos = new_pos; return 0; } case MP_STREAM_FLUSH: |