win32/socket: introduce qemu_socket_select() helper

This is a wrapper for WSAEventSelect, with Error handling. By default,
it will produce a warning, so callers don't have to be modified
now, and yet we can spot potential mis-use.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Message-Id: <20230221124802.4103554-7-marcandre.lureau@redhat.com>

6 files changed, 30 insertions, 10 deletions

diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h
index 97d0243..9f842ae 100644
--- a/include/sysemu/os-win32.h
+++ b/include/sysemu/os-win32.h
@@ -29,6 +29,7 @@
 #include <winsock2.h>
 #include <windows.h>
 #include <ws2tcpip.h>
+#include "qemu/typedefs.h"
 
 #ifdef HAVE_AFUNIX_H
 #include <afunix.h>
@@ -164,6 +165,10 @@ static inline void qemu_funlockfile(FILE *f)
 #endif
 }
 
+/* Helper for WSAEventSelect, to report errors */
+bool qemu_socket_select(SOCKET s, WSAEVENT hEventObject,
+                        long lNetworkEvents, Error **errp);
+
 /* We wrap all the sockets functions so that we can
  * set errno based on WSAGetLastError()
  */
diff --git a/io/channel-socket.c b/io/channel-socket.c
index 2040297..0bc29c4 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -442,7 +442,7 @@ static void qio_channel_socket_finalize(Object *obj)
             }
         }
 #ifdef WIN32
-        WSAEventSelect(ioc->fd, NULL, 0);
+        qemu_socket_select(ioc->fd, NULL, 0, NULL);
 #endif
         closesocket(ioc->fd);
         ioc->fd = -1;
@@ -846,7 +846,7 @@ qio_channel_socket_close(QIOChannel *ioc,
 
     if (sioc->fd != -1) {
 #ifdef WIN32
-        WSAEventSelect(sioc->fd, NULL, 0);
+        qemu_socket_select(sioc->fd, NULL, 0, NULL);
 #endif
         if (qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_LISTEN)) {
             socket_listen_cleanup(sioc->fd, errp);
diff --git a/io/channel-watch.c b/io/channel-watch.c
index ad7c568..6ac4100 100644
--- a/io/channel-watch.c
+++ b/io/channel-watch.c
@@ -281,9 +281,9 @@ GSource *qio_channel_create_socket_watch(QIOChannel *ioc,
     GSource *source;
     QIOChannelSocketSource *ssource;
 
-    WSAEventSelect(socket, ioc->event,
-                   FD_READ | FD_ACCEPT | FD_CLOSE |
-                   FD_CONNECT | FD_WRITE | FD_OOB);
+    qemu_socket_select(socket, ioc->event,
+                       FD_READ | FD_ACCEPT | FD_CLOSE |
+                       FD_CONNECT | FD_WRITE | FD_OOB, NULL);
 
     source = g_source_new(&qio_channel_socket_source_funcs,
                           sizeof(QIOChannelSocketSource));
diff --git a/util/aio-win32.c b/util/aio-win32.c
index 80cfe01..be5136e 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -115,7 +115,7 @@ void aio_set_fd_handler(AioContext *ctx,
 
         QLIST_INSERT_HEAD_RCU(&ctx->aio_handlers, node, node);
         event = event_notifier_get_handle(&ctx->notifier);
-        WSAEventSelect(node->pfd.fd, event, bitmask);
+        qemu_socket_select(node->pfd.fd, event, bitmask, NULL);
     }
     if (old_node) {
         aio_remove_fd_handler(ctx, old_node);
diff --git a/util/main-loop.c b/util/main-loop.c
index 3c0f525..16e837f 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -416,9 +416,9 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 
 void qemu_fd_register(int fd)
 {
-    WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
-                   FD_READ | FD_ACCEPT | FD_CLOSE |
-                   FD_CONNECT | FD_WRITE | FD_OOB);
+    qemu_socket_select(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
+                       FD_READ | FD_ACCEPT | FD_CLOSE |
+                       FD_CONNECT | FD_WRITE | FD_OOB, NULL);
 }
 
 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index 528c9ee..df752fc 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -180,7 +180,7 @@ static int socket_error(void)
 void qemu_socket_set_block(int fd)
 {
     unsigned long opt = 0;
-    WSAEventSelect(fd, NULL, 0);
+    qemu_socket_select(fd, NULL, 0, NULL);
     ioctlsocket(fd, FIONBIO, &opt);
 }
 
@@ -283,6 +283,21 @@ char *qemu_get_pid_name(pid_t pid)
 }
 
 
+bool qemu_socket_select(SOCKET s, WSAEVENT hEventObject,
+                        long lNetworkEvents, Error **errp)
+{
+    if (errp == NULL) {
+        errp = &error_warn;
+    }
+
+    if (WSAEventSelect(s, hEventObject, lNetworkEvents) != 0) {
+        error_setg_win32(errp, WSAGetLastError(), "failed to WSAEventSelect()");
+        return false;
+    }
+
+    return true;
+}
+
 #undef connect
 int qemu_connect_wrap(int sockfd, const struct sockaddr *addr,
                       socklen_t addrlen)