Fix high cpu load for server sockets.

(pfn_WSAEventSelect): New function ptr.
(init_winsock): Load it.
(sys_listen): Set FILE_LISTEN flag. Set event mask for socket's
char_avail event object to FD_ACCEPT.
(sys_accept): Check FILE_LISTEN flag.  Set event mask on new
socket's char_avail event object to FD_READ|FD_CLOSE.

1 files changed, 14 insertions, 2 deletions

diff --git a/src/w32.c b/src/w32.c
index f11ffb7a785..10b912709fc 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -2700,6 +2700,7 @@ utime (const char *name, struct utimbuf *times)
 int (PASCAL *pfn_WSAStartup) (WORD wVersionRequired, LPWSADATA lpWSAData);
 void (PASCAL *pfn_WSASetLastError) (int iError);
 int (PASCAL *pfn_WSAGetLastError) (void);
+int (PASCAL *pfn_WSAEventSelect) (SOCKET s, HANDLE hEventObject, long lNetworkEvents);
 int (PASCAL *pfn_socket) (int af, int type, int protocol);
 int (PASCAL *pfn_bind) (SOCKET s, const struct sockaddr *addr, int namelen);
 int (PASCAL *pfn_connect) (SOCKET s, const struct sockaddr *addr, int namelen);
@@ -2782,6 +2783,7 @@ init_winsock (int load_now)
       LOAD_PROC( WSAStartup );
       LOAD_PROC( WSASetLastError );
       LOAD_PROC( WSAGetLastError );
+      LOAD_PROC( WSAEventSelect );
       LOAD_PROC( socket );
       LOAD_PROC( bind );
       LOAD_PROC( connect );
@@ -3295,6 +3297,11 @@ sys_listen (int s, int backlog)
       int rc = pfn_listen (SOCK_HANDLE (s), backlog);
       if (rc == SOCKET_ERROR)
         set_errno ();
+      else
+        {
+          fd_info[s].flags |= FILE_LISTEN;
+          pfn_WSAEventSelect (SOCK_HANDLE (s), fd_info[s].cp->char_avail, FD_ACCEPT);
+        }
       return rc;
     }
   h_errno = ENOTSOCK;
@@ -3332,11 +3339,16 @@ sys_accept (int s, struct sockaddr * addr, int * addrlen)
     }
 
   check_errno ();
-  if (fd_info[s].flags & FILE_SOCKET)
+  if (fd_info[s].flags & FILE_LISTEN)
     {
       SOCKET t = pfn_accept (SOCK_HANDLE (s), addr, addrlen);
       if (t != INVALID_SOCKET)
-        return socket_to_fd (t);
+        {
+          int fd = socket_to_fd (t);
+          if (fd >= 0)
+            pfn_WSAEventSelect (SOCK_HANDLE (fd), fd_info[fd].cp->char_avail, FD_READ | FD_CLOSE);
+          return fd;
+        }
 
       set_errno ();
       return -1;