os: Use NotifyFd interface for listen descriptors

 Bundle X.org backport of these commits:

 commit 7ea64fb4374504bd3d524fc08c90efdab9f253ea
 Author: Alan Coopersmith <alan.coopersmith@oracle.com>
 Date:   Mon Mar 9 09:55:57 2015 -0700

    Clear ListenTransConns entries in CloseWellKnownConnections

    Since _XSERVTransClose frees the connection pointer passed to it,
    remove that pointer from the array, so we don't try to double free it
    if we come back into CloseWellKnownConnections again.

    Should fix https://bugzilla.yoctoproject.org/show_bug.cgi?id=6665 in which
    the shutdown section of the main() loop called CloseWellKnownConnections()
    and then moved on to ddxGiveUp(), which failed to release the VT and thus
    called AbortServer(), which called CloseWellKnownConnections() again.

    Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

 commit 7b02f0b87ec2fa0cc5a65307a1fd55c671cec884
 Author: Keith Packard <keithp@keithp.com>
 Date:   Wed Nov 11 22:02:17 2015 -0800

    os: Use NotifyFd interface for listen descriptors

    Replace the custom path for dealing with new incoming connections with
    the general-purpose NotifyFd API.

    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Keith Packard <keithp@keithp.com>

 commit ba71b69f94f00a6f6910597185610668e79c10be
 Author: Alan Coopersmith <alan.coopersmith@oracle.com>
 Date:   Fri Jan 1 17:34:41 2016 -0800

    Avoid segfault in CloseWellKnownConnections when using -displayfd

    When -displayfd is looping through the possible display ids to use,
    if it can't open all the listening sockets for one (say when :0 is
    already in use), it calls CloseWellKnownConnections to close all
    the ListenTransConns entries before the point that ListenTransFds
    was allocated & initialized, so CloseWellKnownConnections would
    segfault trying to read entries from a NULL ListenTransFds pointer.

    Introduced by commit 7b02f0b8

    Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
    Reviewed-by: Keith Packard <keithp@keithp.com>

 Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>

2 files changed, 53 insertions, 70 deletions

diff --git a/nx-X11/programs/Xserver/os/WaitFor.c b/nx-X11/programs/Xserver/os/WaitFor.c
index 4d7fe3f84..76e5da5f2 100644
--- a/nx-X11/programs/Xserver/os/WaitFor.c
+++ b/nx-X11/programs/Xserver/os/WaitFor.c
@@ -495,10 +495,6 @@ WaitForSomething(int *pClientsReady)
 	    }
 
 	    XFD_ANDSET(&clientsReadable, &LastSelectMask, &AllClients); 
-	    XFD_ANDSET(&tmp_set, &LastSelectMask, &WellKnownConnections);
-	    if (XFD_ANYSET(&tmp_set))
-		QueueWorkProc(EstablishNewConnections, NULL,
-		              (void *)&LastSelectMask);
 
 	    XFD_ANDSET(&tmp_set, &LastSelectMask, &NotifyReadFds);
 	    if (XFD_ANYSET(&tmp_set) || someNotifyWriteReady)
diff --git a/nx-X11/programs/Xserver/os/connection.c b/nx-X11/programs/Xserver/os/connection.c
index 7638cdfdd..b251c2f5c 100644
--- a/nx-X11/programs/Xserver/os/connection.c
+++ b/nx-X11/programs/Xserver/os/connection.c
@@ -123,7 +123,6 @@ SOFTWARE.
 
 int lastfdesc;			/* maximum file descriptor */
 
-fd_set WellKnownConnections;	/* Listener mask */
 fd_set NotifyReadFds;           /* mask for other file descriptors */
 fd_set NotifyWriteFds;          /* mask for other write file descriptors */
 fd_set AllSockets;		/* select on this */
@@ -152,6 +151,9 @@ static fd_set SavedAllSockets;
 static fd_set SavedClientsWithInput;
 int GrabInProgress = 0;
 
+static void
+QueueNewConnections(int curconn, int ready, void *data);
+
 #if !defined(WIN32)
 int *ConnectionTranslation = NULL;
 #else
@@ -407,8 +409,6 @@ CreateWellKnownSockets(void)
     ClearConnectionTranslation();
 #endif
 
-    FD_ZERO (&WellKnownConnections);
-
     /* display is initialized to "0" by main(). It is then set to the display
      * number if specified on the command line. */
     if (NoListenAll) {
@@ -442,13 +442,13 @@ CreateWellKnownSockets(void)
         int fd = _XSERVTransGetConnectionNumber(ListenTransConns[i]);
 
         ListenTransFds[i] = fd;
-        FD_SET(fd, &WellKnownConnections);
+	SetNotifyFd(fd, QueueNewConnections, X_NOTIFY_READ, NULL);
 
         if (!_XSERVTransIsLocal(ListenTransConns[i]))
             DefineSelf (fd);
     }
 
-    if (!XFD_ANYSET (&WellKnownConnections) && !NoListenAll)
+    if (ListenTransCount == 0 && !NoListenAll)
         FatalError ("Cannot establish any listening sockets - Make sure an X server isn't already running");
 #if !defined(WIN32)
     OsSignal (SIGPIPE, SIG_IGN);
@@ -456,7 +456,6 @@ CreateWellKnownSockets(void)
 #endif
     OsSignal (SIGINT, GiveUp);
     OsSignal (SIGTERM, GiveUp);
-    XFD_COPYSET (&WellKnownConnections, &AllSockets);
     ResetHosts(display);
 
     InitParentProcess();
@@ -525,7 +524,7 @@ ResetWellKnownSockets (void)
 		 * Remove it from out list.
 		 */
 
-		FD_CLR (ListenTransFds[i], &WellKnownConnections);
+		RemoveNotifyFd(ListenTransFds[i]);
 		ListenTransFds[i] = ListenTransFds[ListenTransCount - 1];
 		ListenTransConns[i] = ListenTransConns[ListenTransCount - 1];
 		ListenTransCount -= 1;
@@ -539,13 +538,14 @@ ResetWellKnownSockets (void)
 
 		int newfd = _XSERVTransGetConnectionNumber (ListenTransConns[i]);
 
-		FD_CLR (ListenTransFds[i], &WellKnownConnections);
 		ListenTransFds[i] = newfd;
-		FD_SET(newfd, &WellKnownConnections);
 	    }
 	}
     }
 
+    for (i = 0; i < ListenTransCount; i++)
+	SetNotifyFd(ListenTransFds[i], QueueNewConnections, X_NOTIFY_READ, NULL);
+
     ResetAuthorization ();
     ResetHosts(display);
     /*
@@ -561,8 +561,15 @@ CloseWellKnownConnections(void)
 {
     int i;
 
-    for (i = 0; i < ListenTransCount; i++)
-	_XSERVTransClose (ListenTransConns[i]);
+    for (i = 0; i < ListenTransCount; i++) {
+	if (ListenTransConns[i] != NULL) {
+	    _XSERVTransClose(ListenTransConns[i]);
+	    ListenTransConns[i] = NULL;
+	    if (ListenTransFds != NULL)
+		RemoveNotifyFd(ListenTransFds[i]);
+	}
+    }
+    ListenTransCount = 0;
 }
 
 static void
@@ -827,23 +834,18 @@ AllocNewConnection (XtransConnInfo trans_conn, int fd, CARD32 conn_time)
  *    and AllSockets.
  *****************/
 
-/*ARGSUSED*/
-Bool
+static Bool
 EstablishNewConnections(ClientPtr clientUnused, void * closure)
 {
-    fd_set  readyconnections;     /* set of listeners that are ready */
-    int curconn;                  /* fd of listener that's ready */
-    register int newconn;         /* fd of new client */
+    int curconn = (int) (intptr_t) closure;
+    int newconn;       /* fd of new client */
     CARD32 connect_time;
-    register int i;
-    register ClientPtr client;
-    register OsCommPtr oc;
-    fd_set tmask;
-
-    XFD_ANDSET (&tmask, (fd_set*)closure, &WellKnownConnections);
-    XFD_COPYSET(&tmask, &readyconnections);
-    if (!XFD_ANYSET(&readyconnections))
-	return TRUE;
+    int i;
+    ClientPtr client;
+    OsCommPtr oc;
+    XtransConnInfo trans_conn, new_trans_conn;
+    int status;
+
     connect_time = GetTimeInMillis();
     /* kill off stragglers */
     for (i=1; i<currentMaxClients; i++)
@@ -857,59 +859,44 @@ EstablishNewConnections(ClientPtr clientUnused, void * closure)
 		CloseDownClient(client);     
 	}
     }
-#ifndef WIN32
-    for (i = 0; i < howmany(XFD_SETSIZE, NFDBITS); i++)
-    {
-      while (readyconnections.fds_bits[i])
-#else
-      for (i = 0; i < XFD_SETCOUNT(&readyconnections); i++) 
-#endif
-      {
-	XtransConnInfo trans_conn, new_trans_conn;
-	int status;
-
-#ifndef WIN32
-	curconn = ffs (readyconnections.fds_bits[i]) - 1;
-	readyconnections.fds_bits[i] &= ~((fd_mask)1 << curconn);
-	curconn += (i * (sizeof(fd_mask)*8));
-#else
-	curconn = XFD_FD(&readyconnections, i);
-#endif
+    if ((trans_conn = lookup_trans_conn(curconn)) == NULL)
+	return TRUE;
 
-	if ((trans_conn = lookup_trans_conn (curconn)) == NULL)
-	    continue;
+    if ((new_trans_conn = _XSERVTransAccept(trans_conn, &status)) == NULL)
+	return TRUE;
 
-	if ((new_trans_conn = _XSERVTransAccept (trans_conn, &status)) == NULL)
-	    continue;
+    newconn = _XSERVTransGetConnectionNumber(new_trans_conn);
 
-	newconn = _XSERVTransGetConnectionNumber (new_trans_conn);
+    if (newconn < lastfdesc) {
+	int clientid;
 
-	if (newconn < lastfdesc)
-	{
-		int clientid;
 #if !defined(WIN32)
-  		clientid = ConnectionTranslation[newconn];
+	clientid = ConnectionTranslation[newconn];
 #else
-  		clientid = GetConnectionTranslation(newconn);
+	clientid = GetConnectionTranslation(newconn);
 #endif
-		if(clientid && (client = clients[clientid]))
- 			CloseDownClient(client);
-	}
+	if (clientid && (client = clients[clientid]))
+	    CloseDownClient(client);
+    }
 
-	_XSERVTransSetOption(new_trans_conn, TRANS_NONBLOCKING, 1);
+    _XSERVTransSetOption(new_trans_conn, TRANS_NONBLOCKING, 1);
+
+    if (trans_conn->flags & TRANS_NOXAUTH)
+        new_trans_conn->flags = new_trans_conn->flags | TRANS_NOXAUTH;
+
+    if (!AllocNewConnection(new_trans_conn, newconn, connect_time)) {
+	ErrorConnMax(new_trans_conn);
+     }
 
-	if (!AllocNewConnection (new_trans_conn, newconn, connect_time
-				))
-	{
-	    ErrorConnMax(new_trans_conn);
-	}
-      }
-#ifndef WIN32
-    }
-#endif
     return TRUE;
 }
 
+static void
+QueueNewConnections(int fd, int ready, void *data)
+{
+    QueueWorkProc(EstablishNewConnections, NULL, (void *) (intptr_t) fd);
+}
+
 #define NOROOM "Maximum number of clients reached"
 
 /************