Re: select() on non-sockets in eval.c

Hi,

At Wed, 25 May 2005 15:28:08 +0900,
nobuyoshi nakada wrote in [ruby-core:05090]:
> > In eval.c, select is used to synchronize IO in ruby threads, but on some
> > platforms select() does not work on non-sockets.  We are told that
> > Windows is just such a platform.  However, there are no exceptions in
> > the code to handle the Windows case, which is a bit puzzling.
> > Apparently, by some accident of the Windows select() implementation,
> 
> It is replaced within win32/win32.[ch].

Like the following patch, though I haven't even done compilation.

BTW, I feel that SIZEOF_LONG_LONG must be a preprocess time constant
and should be in config.h.


Index: configure.in
===================================================================
RCS file: /cvs/ruby/src/ruby/configure.in,v
retrieving revision 1.277
diff -U2 -p -u -r1.277 configure.in
--- configure.in	15 May 2005 09:56:49 -0000	1.277
+++ configure.in	25 May 2005 09:14:34 -0000
@@ -1393,4 +1393,7 @@ case "$target_os" in
 	esac
 	;;
+    vms)
+	AC_LIBOBJ([vms])
+	;;
     *)
 	;;
Index: vms/vms.c
===================================================================
RCS file: vms/vms.c
diff -N vms/vms.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ vms/vms.c	25 May 2005 09:05:18 -0000
@@ -0,0 +1,87 @@
+#include "ruby.h"
+#include "defines.h"
+
+static int
+is_socket(int fd)
+{
+    int type, len;
+
+    len = sizeof(type);
+    if (getsockopt(fd, SOL_SOCKET, SO_TYPE, (void *)&type, &len) == 0)
+	return 1;
+    if (errno == ENOTSOCK) errno = 0;
+
+    return 0;
+}
+
+#undef select
+int
+rb_vms_select(int maxfd, fd_set *rfd, fd_set *wfd, fd_set *efd, struct timeval *tv)
+{
+    int i, maxsock, socks, nsocks;
+    fd_set rs, ws, es, *rp, *wp, *ep;
+    struct timeval z;
+
+    FD_ZERO(&rs);
+    FD_ZERO(&ws);
+    FD_ZERO(&es);
+
+    /* count socket and non-socket fds */
+    maxsock = socks = nsocks = 0;
+    if (rfd || wfd || efd) {
+	for (i = 0; i < maxfd; ++i) {
+	    int r = (rfd != 0) && FD_ISSET(i, rfd);
+	    int w = (wfd != 0) && FD_ISSET(i, wfd);
+	    int e = (efd != 0) && FD_ISSET(i, efd);
+	    if (!r && !w && !e) continue;
+	    if (is_socket(i)) {
+		if (r) FD_SET(i, (rp = &rs));
+		if (w) FD_SET(i, (wp = &ws));
+		if (e) FD_SET(i, (ep = &es));
+		maxsock = i + 1;
+		socks++;
+	    }
+	    else {
+		nsocks++;
+	    }
+	}
+    }
+
+    if (!nsocks) {
+	/* sockets only */
+	return select(maxsock, rfd, wfd, efd, tv);
+    }
+
+    if (!socks) {
+	/* assuming non-socket fds are always ready */
+	return nsocks;
+    }
+
+    /* check if sockets are ready */
+    z.tv_sec = 0;
+    z.tv_usec = 0;
+    ret = select(maxsock, rp, wp, ep, &z);
+    if (ret < 0) {
+	if (rfd) *rfd = rs;
+	if (wfd) *wfd = ws;
+	if (efd) *efd = es;
+	return nsocks;
+    }
+
+    for (i = 0; i < maxsock; ++i) {
+	if (rp && FD_ISSET(i, rp)) {
+	    FD_SET(i, rfd);
+	    ret++;
+	}
+	if (wp && FD_ISSET(i, wp)) {
+	    FD_SET(i, wfd);
+	    ret++;
+	}
+	if (ep && FD_ISSET(i, ep)) {
+	    FD_SET(i, efd);
+	    ret++;
+	}
+    }
+
+    return ret;
+}
Index: vms/vms.h
===================================================================
RCS file: /cvs/ruby/src/ruby/vms/vms.h,v
retrieving revision 1.3
diff -U2 -p -r1.3 vms.h
--- vms/vms.h	26 Dec 2003 01:38:31 -0000	1.3
+++ vms/vms.h	25 May 2005 09:05:58 -0000
@@ -10,4 +10,7 @@ extern int vsnprintf();
 extern int snprintf();
 
+int rb_vms_select(int, fd_set*, fd_set*, fd_set*, struct timeval*);
+#define select(n, r, w, e, t) rb_vms_select(n, r, w, e, t)
+
 #define LONG_LONG long long
 #define SIZEOF_LONG_LONG sizeof(long long)


-- 
Nobu Nakada