esp32/modsocket: Try garbage collection if the socket limit is reached.

projectgus · dpgeorge · commit fce8d9fd5540 · 2023-11-20T19:16:16.000+11:00
If the hard socket limit (default 16) is reached then it's possible that
socket allocation fails but garbage collection would allow it to succeed.

Perform a GC pass and try again before giving up, similar to the logic
elsewhere in MicroPython that tries a GC pass before raising MemoryError.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton &lt;angus@redyak.com.au&gt;
diff --git a/ports/esp32/modsocket.c b/ports/esp32/modsocket.c
@@ -36,6 +36,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "py/gc.h"
 #include "py/runtime0.h"
 #include "py/nlr.h"
 #include "py/objlist.h"
@@ -274,6 +275,13 @@ STATIC mp_obj_t socket_make_new(const mp_obj_type_t *type_in, size_t n_args, siz
     sock->state = sock->type == SOCK_STREAM ? SOCKET_STATE_NEW : SOCKET_STATE_CONNECTED;
 
     sock->fd = lwip_socket(sock->domain, sock->type, sock->proto);
+    if (sock->fd < 0 && errno == ENFILE) {
+        // ESP32 LWIP has a hard socket limit, ENFILE is returned when this is
+        // reached. Similar to the logic elsewhere for MemoryError, try running
+        // GC before failing outright.
+        gc_collect();
+        sock->fd = lwip_socket(sock->domain, sock->type, sock->proto);
+    }
     if (sock->fd < 0) {
         mp_raise_OSError(errno);
     }
