[SCM] Samba Shared Repository - branch master updated

[Volker Lendecke]

The branch, master has been updated
       via  5f6f719 s3: Mark sockets in error state writable
      from  cfef10a s3:doc: clean up the example section of the idmap_tdb manpage

http://gitweb.samba.org/?p=samba.git;a=shortlog;h=master


- Log -----------------------------------------------------------------
commit 5f6f71956460d6840c1433b59e20555268b622ac
Author: Volker Lendecke <vl at samba.org>
Date:   Tue May 31 13:24:22 2011 +0200

    s3: Mark sockets in error state writable
    
    Without this patch, when a socket only has a write event pending, we will never
    detect an error condition. I've seen winbind doing
    
    12:19:13.659964 gettimeofday({1306837153, 659984}, NULL) = 0 <0.000016>
    12:19:13.660109 poll([{fd=35, events=POLLOUT}, {fd=32, events=POLLIN|POLLHUP}], 2, 9996) = 1 ([{fd=35, revents=POLLERR|POLLHUP}]) <0.000015>
    12:19:13.660253 gettimeofday({1306837153, 660269}, NULL) = 0 <0.000013>
    12:19:13.660298 poll([{fd=35, events=POLLOUT}, {fd=32, events=POLLIN|POLLHUP}], 2, 9996) = 1 ([{fd=35, revents=POLLERR|POLLHUP}]) <0.000015>
    
    for a while when trying to connect to a DC when the socket had died already.
    
    Volker
    
    Autobuild-User: Volker Lendecke <vlendec at samba.org>
    Autobuild-Date: Tue May 31 20:59:10 CEST 2011 on sn-devel-104

-----------------------------------------------------------------------

Summary of changes:
 source3/lib/events.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)


Changeset truncated at 500 lines:

diff --git a/source3/lib/events.c b/source3/lib/events.c
index 9ff1488..499d92e 100644
--- a/source3/lib/events.c
+++ b/source3/lib/events.c
@@ -260,6 +260,29 @@ bool run_events_poll(struct tevent_context *ev, int pollrtn,
 
 		if (pfd->revents & (POLLIN|POLLHUP|POLLERR)) {
 			flags |= EVENT_FD_READ;
+
+			if ((fde->flags & EVENT_FD_READ) == 0) {
+				/*
+				 * This one is a bit subtle. If a socket is
+				 * not being asked for readability and dies
+				 * with POLLHUP|POLLERR, then the write
+				 * handler must be activated to detect the
+				 * dead socket with a failed write(2)
+				 * call. The error I've seen is winbind
+				 * spinning in poll trying to send something
+				 * to a DC on a dead socket. poll gave
+				 * POLLHUP|POLLERR, but because winbind at
+				 * this moment only had asked for socket
+				 * writability, it spun.
+				 *
+				 * We can't activate EVENT_FD_WRITE though
+				 * whenever we have an error condition via
+				 * POLLHUP|POLLERR, because at least smbd
+				 * monitors EVENT_FD_WRITE in its callback,
+				 * doing nothing.
+				 */
+				flags |= EVENT_FD_WRITE;
+			}
 		}
 		if (pfd->revents & POLLOUT) {
 			flags |= EVENT_FD_WRITE;


-- 
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