Fix fcntl() emulation for Windows

F_GETFL always failed with WSAEINVAL.  io_noblocking() always failed
without doing anything.  Callers didn't check for failure, and newly
opened sockets remained blocking.  But because because
WSAEventSelect() makes sockets non-blocking automatically, they became
non-blocking soon enough to keep things working.

Remove the broken code to query the non-blocking state, and just
return 0.  Document why this works.

While there, simplify the F_SETFL case by using ioctlsocket() instead
of WSAIoctl().

diff --git a/src/lib/w32/posixio.c b/src/lib/w32/posixio.c
index 45a379cfb101b9241f9f7ffd8fb93ec9ef5cf723..143b41c34fc227433b6dc8690824bf7ed1eeca9a 100644 (file)
--- a/src/lib/w32/posixio.c
+++ b/src/lib/w32/posixio.c
@@ -642,18 +642,17 @@ fileno(FILE *stream)
 
 /*
  * POSIX equivalent for fcntl().
- * Currently supports only the F_GETFL/F_SETFL/O_NONBLOCK
- * Currently ignores F_GETLK/F_SETLK as the file locks are
- * implement in open()
+ * Horrible hacks, just good enough support Empire's use of fcntl().
+ * F_GETFL / F_SETFL support making a socket (non-)blocking by getting
+ * flags, adding or removing O_NONBLOCK, and setting the result.
+ * F_SETLK does nothing.  Instead, we lock in posix_open().
  */
 int
 fcntl(int fd, int cmd, ...)
 {
     va_list ap;
     int value;
-    unsigned int nonblocking;
-    int result;
-    long bytes_returned;
+    unsigned long nonblocking;
     int handle;
     enum fdmap_io_type type;
 
@@ -663,52 +662,24 @@ fcntl(int fd, int cmd, ...)
     switch (cmd)
     {
     case F_GETFL:
-       /*
-        * F_GETFL and F_SETFL only support O_NONBLOCK
-        * for sockets currently
-        */
-       if (type == FDMAP_IO_SOCKET) {
-           result = WSAIoctl(handle, FIONBIO, NULL, 0,&nonblocking,
-               sizeof (nonblocking), &bytes_returned, NULL, NULL);
-
-           if(result < 0) {
-               errno = WSAGetLastError();
-               return -1;
-           }
-
-           if (nonblocking)
-               return O_NONBLOCK;
-           else
-               return 0;
-       }
+       if (type == FDMAP_IO_SOCKET)
+           return 0;
        break;
     case F_SETFL:
        if (type == FDMAP_IO_SOCKET) {
            va_start(ap, cmd);
            value = va_arg(ap, int);
            va_end(ap);
-           if (value & O_NONBLOCK)
-               nonblocking = 1;
-           else
-               nonblocking = 0;
-
-           result = WSAIoctl(handle, FIONBIO, &nonblocking,
-               sizeof (nonblocking), NULL, 0, &bytes_returned,
-               NULL, NULL);
+           nonblocking = (value & O_NONBLOCK) != 0;
 
-           if(result < 0) {
+           if (ioctlsocket(handle, FIONBIO, &nonblocking) == SOCKET_ERROR) {
                errno = WSAGetLastError();
                return -1;
            }
-           return result;
+           return 0;
        }
        break;
     case F_SETLK:
-       /*
-        * The POSIX equivalent is not available in WIN32
-        * That implement the file locking in the file open
-        * by using sopen instead of open.
-        */
        return 0;
     }
     errno = EINVAL;