totally rewrote the async signal, notification and oplock notification

handling in Samba. This was needed due to several limitations and
races in the previous code - as a side effect the new code is much
cleaner :)

in summary:

- changed sys_select() to avoid a signal/select race condition. It is a
  rare race but once we have signals doing notification and oplocks it
  is important.

- changed our main processing loop to take advantage of the new
  sys_select semantics

- split the notify code into implementaion dependent and general
  parts. Added the following structure that defines an implementation:

struct cnotify_fns {
	void * (*register_notify)(connection_struct *conn, char *path, uint32 flags);
	BOOL (*check_notify)(connection_struct *conn, uint16 vuid, char *path, uint32 flags, void *data, time_t t);
	void (*remove_notify)(void *data);
};


then I wrote two implementations, one using hash/poll (like our old
code) and the other using the new Linux kernel change notify. It
should be easy to add other change notify implementations by creating
a sructure of the above type.

- fixed a bug in change notify where we were returning the wrong error
  code.

- rewrote the core change notify code to be much simpler

- moved to real-time signals for leases and change notify

Amazingly, it all seems to work. I was very surprised!
(This used to be commit 44766c39e0027c762bee8b33b12c621c109a3267)

1 files changed, 4 insertions, 0 deletions

diff --git a/source3/lib/debug.c b/source3/lib/debug.c
index 675c2d8cfcb..a388956d426 100644
--- a/source3/lib/debug.c
+++ b/source3/lib/debug.c
@@ -132,6 +132,8 @@ void sig_usr2( int sig )
 
   DEBUG( 0, ( "Got SIGUSR2; set debug level to %d.\n", DEBUGLEVEL ) );
 
+  sys_select_signal();
+
 #if !defined(HAVE_SIGACTION)
   CatchSignal( SIGUSR2, SIGNAL_CAST sig_usr2 );
 #endif
@@ -154,6 +156,8 @@ void sig_usr1( int sig )
 
   DEBUG( 0, ( "Got SIGUSR1; set debug level to %d.\n", DEBUGLEVEL ) );
 
+  sys_select_signal();
+
 #if !defined(HAVE_SIGACTION)
   CatchSignal( SIGUSR1, SIGNAL_CAST sig_usr1 );
 #endif