Send and recv all data when necessary

Expose net_recv_all() and net_send_all(), equivalent of net_recv() and
net_send(), but that waits/retries until the requested length has been
transferred.

Use these new functions where it was (wrongly) assumed that the
requested length had been transferred.

app/src/controller.c

@@ -47,7 +47,7 @@ static SDL_bool process_event(struct controller *controller, const struct contro
     if (!length) {
         return SDL_FALSE;
     }
-    int w = net_send(controller->video_socket, serialized_event, length);
+    int w = net_send_all(controller->video_socket, serialized_event, length);
     return w == length;
 }
 

app/src/device.c

@@ -3,7 +3,7 @@
 
 SDL_bool device_read_info(socket_t device_socket, char *device_name, struct size *size) {
     unsigned char buf[DEVICE_NAME_FIELD_LENGTH + 4];
-    int r = net_recv(device_socket, buf, sizeof(buf));
+    int r = net_recv_all(device_socket, buf, sizeof(buf));
     if (r < DEVICE_NAME_FIELD_LENGTH + 4) {
         LOGE("Could not retrieve device information");
         return SDL_FALSE;

app/src/net.c

@@ -51,6 +51,23 @@ ssize_t net_recv(socket_t socket, void *buf, size_t len) {
     return recv(socket, buf, len, 0);
 }
 
+ssize_t net_recv_all(socket_t socket, void *buf, size_t len) {
+    return recv(socket, buf, len, MSG_WAITALL);
+}
+
 ssize_t net_send(socket_t socket, void *buf, size_t len) {
     return send(socket, buf, len, 0);
 }
+
+ssize_t net_send_all(socket_t socket, void *buf, size_t len) {
+    ssize_t w;
+    while (len > 0) {
+        w = send(socket, buf, len, 0);
+        if (w == -1) {
+            return -1;
+        }
+        len -= w;
+        buf += w;
+    }
+    return w;
+}

app/src/net.h

@@ -19,8 +19,12 @@ void net_cleanup(void);
 
 socket_t net_listen(Uint32 addr, Uint16 port, int backlog);
 socket_t net_accept(socket_t server_socket);
+
+// the _all versions wait/retry until len bytes have been written/read
 ssize_t net_recv(socket_t socket, void *buf, size_t len);
+ssize_t net_recv_all(socket_t socket, void *buf, size_t len);
 ssize_t net_send(socket_t socket, void *buf, size_t len);
+ssize_t net_send_all(socket_t socket, void *buf, size_t len);
 void net_close(socket_t socket);
 
 #endif