From: Miles Bader <miles@gnu.org>
Date: Thu, 7 Dec 1995 03:03:31 +0000 (+0000)
Subject: (__select):   Still clear the user's bits for an fd when SELECT_RETURNED isn't set... 
X-Git-Tag: cvs/libc-951208~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0c7b844d256598d5fda1692894fc769ca9f18450;p=platform%2Fupstream%2Fglibc.git

(__select):   Still clear the user's bits for an fd when SELECT_RETURNED isn't set.   Only clear bits in the user's fdsets -- those needing to be set should be     already.   Use SELECT_ALL in appropiate places. (SELECT_ALL): New macro.
---

diff --git a/sysdeps/mach/hurd/select.c b/sysdeps/mach/hurd/select.c
index 3de8f20..84e89c5 100644
--- a/sysdeps/mach/hurd/select.c
+++ b/sysdeps/mach/hurd/select.c
@@ -23,6 +23,12 @@ Cambridge, MA 02139, USA.  */
 #include <stdlib.h>
 #include <string.h>
 
+/* All user select types.  */
+#define SELECT_ALL (SELECT_READ | SELECT_WRITE | SELECT_URG)
+
+/* Used to record that a particular select rpc returned. Must be distinct
+   from SELECT_ALL (which better not have the high bit set).  */
+#define SELECT_RETURNED ((SELECT_ALL << 1) & ~SELECT_ALL)
 
 /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
    readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
@@ -137,8 +143,7 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
 		/* We got an answer.  This is not necessarily the answer to
                    the query we sent just now.  It may correspond to any
                    prior query which timed out before its answer arrived.  */
-		if (tag < 0 || tag > i ||
-		    (type & (SELECT_READ|SELECT_URG|SELECT_WRITE)) == 0)
+		if (tag < 0 || tag > i || (type & SELECT_ALL) == 0)
 		  /* This is not a proper answer to any query we have yet
                      made.  */
 		  err = EGRATUITOUS;
@@ -146,6 +151,7 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
 		  {
 		    /* Some port is ready.  TAG tells us which.  */
 		    types[tag] &= type;
+		    types[tag] |= SELECT_RETURNED;
 		    ++got;
 		  }
 		break;
@@ -213,19 +219,16 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
 		       *(int *) &msg.success.tag_type != *(int *) &inttype ||
 		       *(int *) &msg.success.result_type != *(int *) &inttype)
 		__mach_msg_destroy (&msg);
-	      else if ((msg.success.result &
-			(SELECT_READ|SELECT_WRITE|SELECT_URG)) == 0 ||
+	      else if ((msg.success.result & SELECT_ALL) == 0 ||
 		       msg.success.tag < firstfd || msg.success.tag > lastfd)
 		err = EGRATUITOUS;
 	      else
 		{
 		  /* This is a winning io_select_reply message!
 		     Record the readiness it indicates and send a reply.  */
-		  if (types[msg.success.tag] == 0)
-		    /* This descriptor is ready and it was not before,
-		       so we increment our count of ready descriptors.  */
-		    ++got;
-		  types[msg.success.tag] |= msg.success.result;
+		  types[msg.success.tag] &= msg.success.result;
+		  types[msg.success.tag] |= SELECT_RETURNED;
+		  ++got;
 		}
 	    }
 
@@ -272,24 +275,21 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
   if (err)
     return __hurd_fail (err);
 
-  /* Set the user bitarrays.  */
+  /* Set the user bitarrays.  We only ever have to clear bits, as all desired
+     ones are initially set.  */
   for (i = 0; i < nfds; ++i)
     {
-      if (readfds != NULL)
-	if (types[i] & SELECT_READ)
-	  FD_SET (i, readfds);
-	else
-	  FD_CLR (i, readfds);
-      if (writefds != NULL)
-	if (types[i] & SELECT_WRITE)
-	  FD_SET (i, writefds);
-	else
-	  FD_CLR (i, writefds);
-      if (exceptfds != NULL)
-	if (types[i] & SELECT_URG)
-	  FD_SET (i, exceptfds);
-	else
-	  FD_CLR (i, exceptfds);
+      int type = types[i];
+
+      if ((type & SELECT_RETURNED) == 0)
+	type = 0;
+
+      if (readfds != NULL && (type & SELECT_READ) == 0)
+	FD_CLR (i, readfds);
+      if (writefds != NULL && (type & SELECT_WRITE) == 0)
+	FD_CLR (i, writefds);
+      if (exceptfds != NULL && (type & SELECT_URG) == 0)
+	FD_CLR (i, exceptfds);
     }
 
   return got;