Windows libgps support

Add Windows versions for network functions and disable unused features.

Add detection of various headers and functions that aren't available in
Windows. Note that netlib_localsocket() has no functional implementation
on Windows, but it isn't to be used on that platform and it's not part of
libgps anyway.

Using send() rather than write() seems to work on Windows.

For Windows need to ensure networking is initialised on opening of sockets
(and then correspondingly shutdown upon closing).

Note that within gpsd.h the termios structures and serial related functions
are removed from the Windows build. These are only accessed in serial.c by
gpsd, so since the Windows build is only generating libgps there is
currently no need to modify serial.c.

And for os_compat.h, daemon() is simply disabled under Windows as it's not
used within libgps.

TESTED:
Confirmed compiles under a cross compiler.
Manual build and run of test_libgps on Windows which successfully connects
to a host running GPSD
Manual build DLL version and link with a Windows version of a program
(Viking) that then successfully connects and monitors positions from GPSD

Otherwise no effect on current supported systems.
'scons build-all check' - passes.

Signed-off-by: Fred Wright <fw@fwright.net>

1 files changed, 60 insertions, 2 deletions

diff --git a/libgps_sock.c b/libgps_sock.c
index ea04b8cd..31f73f5c 100644
--- a/libgps_sock.c
+++ b/libgps_sock.c
@@ -16,11 +16,19 @@
 #include <sys/time.h>	 /* expected to have a select(2) prototype a la SuS */
 #include <sys/types.h>
 #include <sys/stat.h>
+#include "gpsd_config.h"
+#ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
+#endif /* HAVE_SYS_SELECT_H */
 #include <unistd.h>
 
 #ifndef USE_QT
+#ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
+#endif /* HAVE_SYS_SOCKET_H */
+#ifdef HAVE_WINSOCK2_H
+#include <winsock2.h>
+#endif /* HAVE_WINSOCK2_H */
 #else
 #include <QTcpSocket>
 #endif /* USE_QT */
@@ -43,6 +51,33 @@ struct privdata_t
 #endif /* LIBGPS_DEBUG */
 };
 
+#ifdef HAVE_WINSOCK2_H
+static bool need_init = TRUE;
+static bool need_finish = TRUE;
+
+static bool windows_init(void)
+/* Ensure socket networking is initialized for Windows. */
+{
+    WSADATA wsadata;
+    /* request access to Windows Sockets API version 2.2 */
+    int res = WSAStartup(MAKEWORD(2, 2), &wsadata);
+    if (res != 0) {
+      libgps_debug_trace((DEBUG_CALLS, "WSAStartup returns error %d\n", res));
+    }
+    return (res == 0);
+}
+
+static bool windows_finish(void)
+/* Shutdown Windows Sockets. */
+{
+  int res = WSACleanup();
+  if (res != 0) {
+    libgps_debug_trace((DEBUG_CALLS, "WSACleanup returns error %d\n", res));
+  }
+  return (res == 0);
+}
+#endif /* HAVE_WINSOCK2_H */
+
 int gps_sock_open(const char *host, const char *port,
 		  struct gps_data_t *gpsdata)
 {
@@ -54,6 +89,11 @@ int gps_sock_open(const char *host, const char *port,
     libgps_debug_trace((DEBUG_CALLS, "gps_sock_open(%s, %s)\n", host, port));
 
 #ifndef USE_QT
+#ifdef HAVE_WINSOCK2_H
+	if (need_init) {
+	  need_init != windows_init();
+	}
+#endif
 	if ((gpsdata->gps_fd =
 	    netlib_connectsock(AF_UNSPEC, host, port, "tcp")) < 0) {
 	    errno = gpsdata->gps_fd;
@@ -62,7 +102,7 @@ int gps_sock_open(const char *host, const char *port,
         }
 	else
 	    libgps_debug_trace((DEBUG_CALLS, "netlib_connectsock() returns socket on fd %d\n", gpsdata->gps_fd));
-#else
+#else /* HAVE_WINSOCK2_H */
 	QTcpSocket *sock = new QTcpSocket();
 	gpsdata->gps_fd = sock;
 	sock->connectToHost(host, QString(port).toInt());
@@ -119,7 +159,14 @@ int gps_sock_close(struct gps_data_t *gpsdata)
     gpsdata->privdata = NULL;
 #ifndef USE_QT
     int status;
+#ifdef HAVE_WINSOCK2_H
+    status = closesocket(gpsdata->gps_fd);
+    if (need_finish) {
+      need_finish != windows_finish();
+    }
+#else
     status = close(gpsdata->gps_fd);
+#endif /* HAVE_WINSOCK2_H */
     gpsdata->gps_fd = -1;
     return status;
 #else
@@ -160,7 +207,9 @@ int gps_sock_read(struct gps_data_t *gpsdata)
 						     sizeof(PRIVATE(gpsdata)->buffer) -
 						     PRIVATE(gpsdata)->waiting);
 #endif
-
+#ifdef HAVE_WINSOCK2_H
+	int wserr = WSAGetLastError();
+#endif /* HAVE_WINSOCK2_H */
 	/* if we just received data from the socket, it's in the buffer */
 	if (status > -1)
 	    PRIVATE(gpsdata)->waiting += status;
@@ -175,9 +224,14 @@ int gps_sock_read(struct gps_data_t *gpsdata)
 		return -1;
 #ifndef USE_QT
 	    /* count transient errors as success, we'll retry later */
+#ifdef HAVE_WINSOCK2_H
+	    else if (wserr == WSAEINTR || wserr == WSAEWOULDBLOCK)
+		return 0;
+#else
 	    else if (errno == EINTR || errno == EAGAIN
 		     || errno == EWOULDBLOCK)
 		return 0;
+#endif /* HAVE_WINSOCK2_H */
 #endif
 	    /* hard error return of -1, pass it along */
 	    else
@@ -245,7 +299,11 @@ int gps_sock_send(struct gps_data_t *gpsdata, const char *buf)
 /* send a command to the gpsd instance */
 {
 #ifndef USE_QT
+#ifdef HAVE_WINSOCK2_H
+    if (send(gpsdata->gps_fd, buf, strlen(buf), 0) == (ssize_t) strlen(buf))
+#else
     if (write(gpsdata->gps_fd, buf, strlen(buf)) == (ssize_t) strlen(buf))
+#endif /* HAVE_WINSOCK2_H */
 	return 0;
     else
 	return -1;