extmod/modlwip: Check for state change during recv busy-wait loop.

dpgeorge · pfalcon · commit 6d2e9e70b33a · 2016-03-09T12:29:40.000+07:00
For example, the peer may close the connection while recv is waiting for
incoming data.
diff --git a/extmod/modlwip.c b/extmod/modlwip.c
@@ -391,13 +391,19 @@ STATIC mp_uint_t lwip_tcp_receive(lwip_socket_obj_t *socket, byte *buf, mp_uint_
 
     if (socket->incoming.pbuf == NULL) {
         mp_uint_t start = mp_hal_ticks_ms();
-        while (socket->incoming.pbuf == NULL) {
+        while (socket->state == STATE_CONNECTED && socket->incoming.pbuf == NULL) {
             if (socket->timeout != -1 && mp_hal_ticks_ms() - start > socket->timeout) {
                 *_errno = ETIMEDOUT;
                 return -1;
             }
             poll_sockets();
         }
+        if (socket->state == STATE_PEER_CLOSED) {
+            return 0;
+        } else if (socket->state != STATE_CONNECTED) {
+            *_errno = -socket->state;
+            return -1;
+        }
     }
 
     struct pbuf *p = socket->incoming.pbuf;

Original file line number	Diff line number	Diff line change
`@@ -391,13 +391,19 @@ STATIC mp_uint_t lwip_tcp_receive(lwip_socket_obj_t socket, byte buf, mp_uint_`
`391`	`391`
`392`	`392`	`if (socket->incoming.pbuf == NULL) {`
`393`	`393`	`mp_uint_t start = mp_hal_ticks_ms();`
`394`		`- while (socket->incoming.pbuf == NULL) {`
	`394`	`+ while (socket->state == STATE_CONNECTED && socket->incoming.pbuf == NULL) {`
`395`	`395`	`if (socket->timeout != -1 && mp_hal_ticks_ms() - start > socket->timeout) {`
`396`	`396`	`*_errno = ETIMEDOUT;`
`397`	`397`	`return -1;`
`398`	`398`	`}`
`399`	`399`	`poll_sockets();`
`400`	`400`	`}`
	`401`	`+ if (socket->state == STATE_PEER_CLOSED) {`
	`402`	`+ return 0;`
	`403`	`+ } else if (socket->state != STATE_CONNECTED) {`
	`404`	`+ *_errno = -socket->state;`
	`405`	`+ return -1;`
	`406`	`+ }`
`401`	`407`	`}`
`402`	`408`
`403`	`409`	`struct pbuf *p = socket->incoming.pbuf;`