ipc: ref count socket descriptors

src/include/kernel/socket.h

@@ -68,6 +68,7 @@ typedef struct SocketDescriptor {
     size_t *inboundLen, *outboundLen;
     struct SocketDescriptor **backlog;  // for incoming connections via connect()
     struct SocketDescriptor *peer;      // for peer-to-peer connections
+    int refCount;
 } SocketDescriptor;
 
 void socketInit();

src/ipc/connection.c

@@ -151,6 +151,7 @@ int accept(Thread *t, int sd, struct sockaddr *addr, socklen_t *len) {
 
     // copy the self address
     SocketDescriptor *self = (SocketDescriptor *)iod->data;
+    self->refCount = 1;
     memcpy(&self->address, &listener->address, sizeof(struct sockaddr));
     self->type = listener->type;
     self->protocol = listener->protocol;

src/ipc/sockinit.c

@@ -151,6 +151,7 @@ int socket(Thread *t, int domain, int type, int protocol) {
 
     // set up the socket family for now
     SocketDescriptor *sock = (SocketDescriptor *)iod->data;
+    sock->refCount = 1;
     sock->process = p;
     sock->address.sa_family = domain;
     sock->type = type & 0xFF;