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Prevent possible bad garbage collection when finalizing streams. 

The GC finalizer for streams would sometimes try and use other objects
after they had already been freed.
This commit is contained in:
Calvin Rose 2021-07-20 19:42:35 -05:00
parent a125218d03
commit e7ea39f410
1 changed files with 36 additions and 27 deletions
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63
src/core/ev.c
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@ -150,7 +150,7 @@ static int janet_q_pop(JanetQueue *q, void *out, size_t itemsize) {
}
/* Forward declaration */
static void janet_unlisten(JanetListenerState *state);
static void janet_unlisten(JanetListenerState *state, int is_gc);
/* Get current timestamp (millisecond precision) */
static JanetTimestamp ts_now(void);
@ -266,7 +266,7 @@ static JanetListenerState *janet_listen_impl(JanetStream *stream, JanetListener
/* Indicate we are no longer listening for an event. This
* frees the memory of the state machine as well. */
static void janet_unlisten_impl(JanetListenerState *state) {
static void janet_unlisten_impl(JanetListenerState *state, int is_gc) {
state->machine(state, JANET_ASYNC_EVENT_DEINIT);
/* Remove state machine from poll list */
JanetListenerState **iter = &(state->stream->state);
@ -277,9 +277,11 @@ static void janet_unlisten_impl(JanetListenerState *state) {
/* Remove mask */
state->stream->_mask &= ~(state->_mask);
/* Ensure fiber does not reference this state */
JanetFiber *fiber = state->fiber;
if (NULL != fiber && fiber->waiting == state) {
fiber->waiting = NULL;
if (!is_gc) {
JanetFiber *fiber = state->fiber;
if (NULL != fiber && fiber->waiting == state) {
fiber->waiting = NULL;
}
}
/* Untrack a listener for gc purposes */
size_t index = state->_index;
@ -308,22 +310,16 @@ JanetStream *janet_stream(JanetHandle handle, uint32_t flags, const JanetMethod
return stream;
}
/* Called to clean up a stream */
static int janet_stream_gc(void *p, size_t s) {
(void) s;
JanetStream *stream = (JanetStream *)p;
janet_stream_close(stream);
return 0;
}
/* Close a stream */
void janet_stream_close(JanetStream *stream) {
static void janet_stream_close_impl(JanetStream *stream, int is_gc) {
if (stream->flags & JANET_STREAM_CLOSED) return;
JanetListenerState *state = stream->state;
while (NULL != state) {
state->machine(state, JANET_ASYNC_EVENT_CLOSE);
if (!is_gc) {
state->machine(state, JANET_ASYNC_EVENT_CLOSE);
}
JanetListenerState *next_state = state->_next;
janet_unlisten(state);
janet_unlisten(state, is_gc);
state = next_state;
}
stream->state = NULL;
@ -342,6 +338,19 @@ void janet_stream_close(JanetStream *stream) {
#endif
}
void janet_stream_close(JanetStream *stream) {
janet_stream_close_impl(stream, 0);
}
/* Called to clean up a stream */
static int janet_stream_gc(void *p, size_t s) {
(void) s;
JanetStream *stream = (JanetStream *)p;
janet_stream_close_impl(stream, 1);
return 0;
}
/* Mark a stream for GC */
static int janet_stream_mark(void *p, size_t s) {
(void) s;
@ -458,7 +467,7 @@ void janet_fiber_did_resume(JanetFiber *fiber) {
/* Cancel any pending fibers */
if (fiber->waiting) {
fiber->waiting->machine(fiber->waiting, JANET_ASYNC_EVENT_CANCEL);
janet_unlisten(fiber->waiting);
janet_unlisten(fiber->waiting, 0);
}
}
@ -978,8 +987,8 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
}
static void janet_unlisten(JanetListenerState *state) {
janet_unlisten_impl(state);
static void janet_unlisten(JanetListenerState *state, int is_gc) {
janet_unlisten_impl(state, is_gc);
}
void janet_loop1_impl(int has_timeout, JanetTimestamp to) {
@ -1018,7 +1027,7 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp to) {
state->bytes = num_bytes_transfered;
JanetAsyncStatus status = state->machine(state, JANET_ASYNC_EVENT_COMPLETE);
if (status == JANET_ASYNC_STATUS_DONE) {
janet_unlisten(state);
janet_unlisten(state, 0);
}
break;
} else {
@ -1061,14 +1070,14 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
status = epoll_ctl(janet_vm.epoll, op, stream->handle, &ev);
} while (status == -1 && errno == EINTR);
if (status == -1) {
janet_unlisten_impl(state);
janet_unlisten_impl(state, 0);
janet_panicv(janet_ev_lasterr());
}
return state;
}
/* Tell system we are done listening for a certain event */
static void janet_unlisten(JanetListenerState *state) {
static void janet_unlisten(JanetListenerState *state, int is_gc) {
JanetStream *stream = state->stream;
if (!(stream->flags & JANET_STREAM_CLOSED)) {
int is_last = (state->_next == NULL && stream->state == state);
@ -1085,7 +1094,7 @@ static void janet_unlisten(JanetListenerState *state) {
}
}
/* Destroy state machine and free memory */
janet_unlisten_impl(state);
janet_unlisten_impl(state, is_gc);
}
#define JANET_EPOLL_MAX_EVENTS 64
@ -1142,7 +1151,7 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
status2 == JANET_ASYNC_STATUS_DONE ||
status3 == JANET_ASYNC_STATUS_DONE ||
status4 == JANET_ASYNC_STATUS_DONE)
janet_unlisten(state);
janet_unlisten(state, 0);
state = next_state;
}
}
@ -1220,9 +1229,9 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
return state;
}
static void janet_unlisten(JanetListenerState *state) {
static void janet_unlisten(JanetListenerState *state, int is_gc) {
janet_vm.fds[state->_index + 1] = janet_vm.fds[janet_vm.listener_count];
janet_unlisten_impl(state);
janet_unlisten_impl(state, is_gc);
}
void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
@ -1270,7 +1279,7 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
status2 == JANET_ASYNC_STATUS_DONE ||
status3 == JANET_ASYNC_STATUS_DONE ||
status4 == JANET_ASYNC_STATUS_DONE)
janet_unlisten(state);
janet_unlisten(state, 0);
}
}