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extmod/os_dupterm: Prevent recursive execution of mp_os_dupterm_rx_chr. 

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2023-12-14 17:08:04 +11:00
parent 395886caa3
commit 1f2ec4583d
1 changed files with 27 additions and 6 deletions
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33
extmod/os_dupterm.c
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@ -94,6 +94,22 @@ uintptr_t mp_os_dupterm_poll(uintptr_t poll_flags) {
}
int mp_os_dupterm_rx_chr(void) {
#if MICROPY_PY_OS_DUPTERM_NOTIFY
// When os.dupterm_notify() is enabled it is usually called from a scheduled
// function, via mp_os_dupterm_notify(). That can lead to recursive calls of
// this function when this function is called from mp_hal_stdin_rx_chr():
// - mp_hal_stdin_rx_chr()
// - mp_os_dupterm_rx_chr()
// - <Python code>
// - os.dupterm_notify() is scheduled via interrupt/event
// - <Python code> runs scheduled code (eg WebREPL -> rp2.Flash().writeblocks())
// - mp_os_dupterm_notify()
// - mp_os_dupterm_rx_chr()
// Break that cycle by locking the scheduler during this function's duration.
mp_sched_lock();
#endif
int ret = -1; // no chars available
for (size_t idx = 0; idx < MICROPY_PY_OS_DUPTERM; ++idx) {
if (MP_STATE_VM(dupterm_objs[idx]) == MP_OBJ_NULL) {
continue;
@ -106,7 +122,8 @@ int mp_os_dupterm_rx_chr(void) {
const mp_stream_p_t *stream_p = mp_get_stream(MP_STATE_VM(dupterm_objs[idx]));
mp_uint_t out_sz = stream_p->read(MP_STATE_VM(dupterm_objs[idx]), buf, 1, &errcode);
if (errcode == 0 && out_sz != 0) {
return buf[0];
ret = buf[0];
break;
} else {
continue;
}
@ -132,20 +149,24 @@ int mp_os_dupterm_rx_chr(void) {
} else {
// read 1 byte
nlr_pop();
if (buf[0] == mp_interrupt_char) {
ret = buf[0];
if (ret == mp_interrupt_char) {
// Signal keyboard interrupt to be raised as soon as the VM resumes
mp_sched_keyboard_interrupt();
return -2;
ret = -2;
}
return buf[0];
break;
}
} else {
mp_os_deactivate(idx, "dupterm: Exception in read() method, deactivating: ", MP_OBJ_FROM_PTR(nlr.ret_val));
}
}
// No chars available
return -1;
#if MICROPY_PY_OS_DUPTERM_NOTIFY
mp_sched_unlock();
#endif
return ret;
}
void mp_os_dupterm_tx_strn(const char *str, size_t len) {