From 94b3ee1366fddb9aca95f2f1ec61d633deb66510 Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Thu, 21 Jan 1999 22:25:43 +0000
Subject: Made to compile after hacking tftp driver into beginnings of a
 mini-filesystem.

---
 c/src/lib/libnetworking/rtems/rtems_select.c | 171 +++++++++++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 c/src/lib/libnetworking/rtems/rtems_select.c

(limited to 'c/src/lib/libnetworking/rtems/rtems_select.c')

diff --git a/c/src/lib/libnetworking/rtems/rtems_select.c b/c/src/lib/libnetworking/rtems/rtems_select.c
new file mode 100644
index 0000000000..2487edf9fc
--- /dev/null
+++ b/c/src/lib/libnetworking/rtems/rtems_select.c
@@ -0,0 +1,171 @@
+/*
+ *  $Id$
+ */
+
+#include <string.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <rtems.h>
+#include <rtems/libio.h>
+#include <rtems/error.h>
+#include <rtems/rtems_bsdnet.h>
+
+#include <sys/errno.h>
+#include <sys/fcntl.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/protosw.h>
+#include <sys/proc.h>
+#include <sys/filio.h>
+
+#include <net/if.h>
+#include <net/route.h>
+
+/*
+ *********************************************************************
+ *            RTEMS implementation of select() system call           *
+ *********************************************************************
+ */
+
+/*
+ * This implementation is quite restricted:
+ *	Works on sockets only -- no support for other devices!
+ *	A given socket can be in a read-select or a read/recv* by only
+ *		one task at a time.
+ *	A given socket can be in a write-select or a write/send* by only
+ *		one task at a time.
+ *
+ * NOTE - select() is a very expensive system call.  It should be avoided
+ *        if at all possible.  In many cases, rewriting the application
+ *        to use multiple tasks (one per socket) is a better solution.
+ */
+
+static __inline int imin(int a, int b) { return (a < b ? a : b); }
+
+static int
+socket_select (struct socket *so, int which, rtems_id tid)
+{
+	switch (which) {
+
+	case FREAD:
+		if (soreadable(so))
+			return (1);
+		so->so_rcv.sb_sel.si_pid = tid;
+		break;
+
+	case FWRITE:
+		if (sowriteable(so))
+			return (1);
+		so->so_snd.sb_sel.si_pid = tid;
+		break;
+
+	case 0:
+		if (so->so_oobmark || (so->so_state & SS_RCVATMARK))
+			return (1);
+		so->so_rcv.sb_sel.si_pid = tid;
+		break;
+	}
+	return (0);
+}
+
+static int
+selscan (rtems_id tid, fd_mask **ibits, fd_mask **obits, int nfd, int *retval)
+{
+	struct socket *so;
+	int msk, i, fd;
+	fd_mask bits, bit;
+	int n = 0;
+	static int flag[3] = { FREAD, FWRITE, 0 };
+
+	for (msk = 0; msk < 3; msk++) {
+		if (ibits[msk] == NULL)
+			continue;
+		for (i = 0; i < nfd; i += NFDBITS) {
+			bits = ibits[msk][i/NFDBITS];
+			for (fd = i, bit = 1 ; bits && (fd < nfd) ; fd++, bit <<= 1) {
+				if ((bits & bit) == 0)
+					continue;
+				bits &= ~bit;
+				so = rtems_bsdnet_fdToSocket (fd);
+				if (so == NULL)
+					return (EBADF);
+				if (socket_select (so, flag[msk], tid)) {
+					obits[msk][fd/NFDBITS] |= 
+							(1 << (fd % NFDBITS));
+					n++;
+				}
+			}
+		}
+	}
+	*retval = n;
+	return (0);
+}
+
+int
+select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *tv)
+{
+	fd_mask *ibits[3], *obits[3];
+	fd_set ob[3];
+	int error, timo;
+	int retval;
+	rtems_id tid;
+	rtems_interval then, now;
+	rtems_event_set events;
+
+	if (nfds < 0)
+		return (EINVAL);
+	if (tv) {
+		timo = tv->tv_sec * hz + tv->tv_usec / tick;
+		if (timo == 0)
+			timo = 1;
+		rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &then);
+	}
+	else {
+		timo = 0;
+	}
+
+#define getbits(name,i) if (name) { \
+		ibits[i] = &name->fds_bits[0]; \
+		obits[i] = &ob[i].fds_bits[0]; \
+		FD_ZERO(&ob[i]); \
+	} \
+	else ibits[i] = NULL
+	getbits (readfds, 0);
+	getbits (writefds, 1);
+	getbits (exceptfds, 2);
+#undef getbits
+
+	rtems_task_ident (RTEMS_SELF, 0, &tid);
+	rtems_event_receive (SBWAIT_EVENT, RTEMS_EVENT_ANY | RTEMS_NO_WAIT, RTEMS_NO_TIMEOUT, &events); 
+	for (;;) {
+		rtems_bsdnet_semaphore_obtain ();
+		error = selscan(tid, ibits, obits, nfds, &retval);
+		rtems_bsdnet_semaphore_release ();
+		if (error || retval)
+			break;
+		if (timo) {
+			rtems_clock_get (RTEMS_CLOCK_GET_TICKS_SINCE_BOOT, &now);
+			timo -= now - then;
+			if (timo <= 0)
+				break;
+			then = now;
+		}
+		rtems_event_receive (SBWAIT_EVENT, RTEMS_EVENT_ANY | RTEMS_WAIT, timo, &events);
+	}
+
+#define putbits(name,i) if (name) *name = ob[i]
+	putbits (readfds, 0);
+	putbits (writefds, 1);
+	putbits (exceptfds, 2);
+#undef putbits
+	if (error) {
+		errno = error;
+		retval = -1;
+	}
+	return (retval);
+}
-- 
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