svn commit: r190997 - in stable/7/sys: . contrib/pf dev/ath/ath_hal dev/cxgb kern

[Robert Watson]

Author: rwatson
Date: Mon Apr 13 11:54:22 2009
New Revision: 190997
URL: http://svn.freebsd.org/changeset/base/190997

Log:
  Merge r190996 from head to stable/7:
  
    When writing out updated pollfd records when returning from
    poll(), only copy out the revents field, not the whole pollfd
    structure.  Otherwise, if the events field is updated
    concurrently by another thread, that update may be lost.
  
    This issue apparently causes problems for the JDK on FreeBSD,
    which expects the Linux behavior of not updating all fields
    (somewhat oddly, Solaris does not implement the required
    behavior, but presumably our adaptation of the JDK is based
    on the Linux port?).
  
    MFC after:      2 weeks
    PR:             kern/130924
    Submitted by:   Kurt Miller <kurt @ intricatesoftware.com>
    Discussed with: kib
  
  Approved by:	re (kib)

Modified:
  stable/7/sys/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)
  stable/7/sys/dev/ath/ath_hal/   (props changed)
  stable/7/sys/dev/cxgb/   (props changed)
  stable/7/sys/kern/sys_generic.c

Modified: stable/7/sys/kern/sys_generic.c
==============================================================================
--- stable/7/sys/kern/sys_generic.c	Mon Apr 13 10:41:41 2009	(r190996)
+++ stable/7/sys/kern/sys_generic.c	Mon Apr 13 11:54:22 2009	(r190997)
@@ -73,6 +73,7 @@ static MALLOC_DEFINE(M_IOCTLOPS, "ioctlo
 static MALLOC_DEFINE(M_SELECT, "select", "select() buffer");
 MALLOC_DEFINE(M_IOV, "iov", "large iov's");
 
+static int	pollout(struct pollfd *, struct pollfd *, u_int);
 static int	pollscan(struct thread *, struct pollfd *, u_int);
 static int	selscan(struct thread *, fd_mask **, fd_mask **, int);
 static int	dofileread(struct thread *, int, struct file *, struct uio *,
@@ -992,7 +993,7 @@ done_nosellock:
 	if (error == EWOULDBLOCK)
 		error = 0;
 	if (error == 0) {
-		error = copyout(bits, uap->fds, ni);
+		error = pollout(bits, uap->fds, nfds);
 		if (error)
 			goto out;
 	}
@@ -1004,6 +1005,26 @@ done2:
 }
 
 static int
+pollout(fds, ufds, nfd)
+	struct pollfd *fds;
+	struct pollfd *ufds;
+	u_int nfd;
+{
+	int error = 0;
+	u_int i = 0;
+
+	for (i = 0; i < nfd; i++) {
+		error = copyout(&fds->revents, &ufds->revents,
+		    sizeof(ufds->revents));
+		if (error)
+			return (error);
+		fds++;
+		ufds++;
+	}
+	return (0);
+}
+
+static int
 pollscan(td, fds, nfd)
 	struct thread *td;
 	struct pollfd *fds;