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Prevent possible bad garbage collection when finalizing streams.

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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 */ /* Forward declaration */
static void janet_unlisten(JanetListenerState *state); static void janet_unlisten(JanetListenerState *state, int is_gc);
/* Get current timestamp (millisecond precision) */ /* Get current timestamp (millisecond precision) */
static JanetTimestamp ts_now(void); 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 /* Indicate we are no longer listening for an event. This
* frees the memory of the state machine as well. */ * 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); state->machine(state, JANET_ASYNC_EVENT_DEINIT);
/* Remove state machine from poll list */ /* Remove state machine from poll list */
JanetListenerState **iter = &(state->stream->state); JanetListenerState **iter = &(state->stream->state);
@ -277,9 +277,11 @@ static void janet_unlisten_impl(JanetListenerState *state) {
/* Remove mask */ /* Remove mask */
state->stream->_mask &= ~(state->_mask); state->stream->_mask &= ~(state->_mask);
/* Ensure fiber does not reference this state */ /* Ensure fiber does not reference this state */
JanetFiber *fiber = state->fiber; if (!is_gc) {
if (NULL != fiber && fiber->waiting == state) { JanetFiber *fiber = state->fiber;
fiber->waiting = NULL; if (NULL != fiber && fiber->waiting == state) {
fiber->waiting = NULL;
}
} }
/* Untrack a listener for gc purposes */ /* Untrack a listener for gc purposes */
size_t index = state->_index; size_t index = state->_index;
@ -308,22 +310,16 @@ JanetStream *janet_stream(JanetHandle handle, uint32_t flags, const JanetMethod
return stream; 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 */ /* 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; if (stream->flags & JANET_STREAM_CLOSED) return;
JanetListenerState *state = stream->state; JanetListenerState *state = stream->state;
while (NULL != 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; JanetListenerState *next_state = state->_next;
janet_unlisten(state); janet_unlisten(state, is_gc);
state = next_state; state = next_state;
} }
stream->state = NULL; stream->state = NULL;
@ -342,6 +338,19 @@ void janet_stream_close(JanetStream *stream) {
#endif #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 */ /* Mark a stream for GC */
static int janet_stream_mark(void *p, size_t s) { static int janet_stream_mark(void *p, size_t s) {
(void) s; (void) s;
@ -458,7 +467,7 @@ void janet_fiber_did_resume(JanetFiber *fiber) {
/* Cancel any pending fibers */ /* Cancel any pending fibers */
if (fiber->waiting) { if (fiber->waiting) {
fiber->waiting->machine(fiber->waiting, JANET_ASYNC_EVENT_CANCEL); 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) { static void janet_unlisten(JanetListenerState *state, int is_gc) {
janet_unlisten_impl(state); janet_unlisten_impl(state, is_gc);
} }
void janet_loop1_impl(int has_timeout, JanetTimestamp to) { 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; state->bytes = num_bytes_transfered;
JanetAsyncStatus status = state->machine(state, JANET_ASYNC_EVENT_COMPLETE); JanetAsyncStatus status = state->machine(state, JANET_ASYNC_EVENT_COMPLETE);
if (status == JANET_ASYNC_STATUS_DONE) { if (status == JANET_ASYNC_STATUS_DONE) {
janet_unlisten(state); janet_unlisten(state, 0);
} }
break; break;
} else { } else {
@ -1061,14 +1070,14 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
status = epoll_ctl(janet_vm.epoll, op, stream->handle, &ev); status = epoll_ctl(janet_vm.epoll, op, stream->handle, &ev);
} while (status == -1 && errno == EINTR); } while (status == -1 && errno == EINTR);
if (status == -1) { if (status == -1) {
janet_unlisten_impl(state); janet_unlisten_impl(state, 0);
janet_panicv(janet_ev_lasterr()); janet_panicv(janet_ev_lasterr());
} }
return state; return state;
} }
/* Tell system we are done listening for a certain event */ /* 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; JanetStream *stream = state->stream;
if (!(stream->flags & JANET_STREAM_CLOSED)) { if (!(stream->flags & JANET_STREAM_CLOSED)) {
int is_last = (state->_next == NULL && stream->state == state); 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 */ /* Destroy state machine and free memory */
janet_unlisten_impl(state); janet_unlisten_impl(state, is_gc);
} }
#define JANET_EPOLL_MAX_EVENTS 64 #define JANET_EPOLL_MAX_EVENTS 64
@ -1142,7 +1151,7 @@ void janet_loop1_impl(int has_timeout, JanetTimestamp timeout) {
status2 == JANET_ASYNC_STATUS_DONE || status2 == JANET_ASYNC_STATUS_DONE ||
status3 == JANET_ASYNC_STATUS_DONE || status3 == JANET_ASYNC_STATUS_DONE ||
status4 == JANET_ASYNC_STATUS_DONE) status4 == JANET_ASYNC_STATUS_DONE)
janet_unlisten(state); janet_unlisten(state, 0);
state = next_state; state = next_state;
} }
} }
@ -1220,9 +1229,9 @@ JanetListenerState *janet_listen(JanetStream *stream, JanetListener behavior, in
return state; 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_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) { 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 || status2 == JANET_ASYNC_STATUS_DONE ||
status3 == JANET_ASYNC_STATUS_DONE || status3 == JANET_ASYNC_STATUS_DONE ||
status4 == JANET_ASYNC_STATUS_DONE) status4 == JANET_ASYNC_STATUS_DONE)
janet_unlisten(state); janet_unlisten(state, 0);
} }
} }