Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1090 insertions, 0 deletions

diff --git a/lib/tevent/tevent.c b/lib/tevent/tevent.c
new file mode 100644
index 0000000..262fdaa
--- /dev/null
+++ b/lib/tevent/tevent.c
@@ -0,0 +1,1090 @@
+/* 
+   Unix SMB/CIFS implementation.
+   main select loop and event handling
+   Copyright (C) Andrew Tridgell 2003
+   Copyright (C) Stefan Metzmacher 2009
+
+     ** NOTE! The following LGPL license applies to the tevent
+     ** library. This does NOT imply that all of Samba is released
+     ** under the LGPL
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+  PLEASE READ THIS BEFORE MODIFYING!
+
+  This module is a general abstraction for the main select loop and
+  event handling. Do not ever put any localised hacks in here, instead
+  register one of the possible event types and implement that event
+  somewhere else.
+
+  There are 2 types of event handling that are handled in this module:
+
+  1) a file descriptor becoming readable or writeable. This is mostly
+     used for network sockets, but can be used for any type of file
+     descriptor. You may only register one handler for each file
+     descriptor/io combination or you will get unpredictable results
+     (this means that you can have a handler for read events, and a
+     separate handler for write events, but not two handlers that are
+     both handling read events)
+
+  2) a timed event. You can register an event that happens at a
+     specific time.  You can register as many of these as you
+     like. They are single shot - add a new timed event in the event
+     handler to get another event.
+
+  To setup a set of events you first need to create a event_context
+  structure using the function tevent_context_init(); This returns a
+  'struct tevent_context' that you use in all subsequent calls.
+
+  After that you can add/remove events that you are interested in
+  using tevent_add_*() and talloc_free()
+
+  Finally, you call tevent_loop_wait_once() to block waiting for one of the
+  events to occor or tevent_loop_wait() which will loop
+  forever.
+
+*/
+#include "replace.h"
+#include "system/filesys.h"
+#ifdef HAVE_PTHREAD
+#include "system/threads.h"
+#endif
+#define TEVENT_DEPRECATED 1
+#include "tevent.h"
+#include "tevent_internal.h"
+#include "tevent_util.h"
+#ifdef HAVE_EVENTFD
+#include <sys/eventfd.h>
+#endif
+
+struct tevent_ops_list {
+	struct tevent_ops_list *next, *prev;
+	const char *name;
+	const struct tevent_ops *ops;
+};
+
+/* list of registered event backends */
+static struct tevent_ops_list *tevent_backends = NULL;
+static char *tevent_default_backend = NULL;
+
+/*
+  register an events backend
+*/
+bool tevent_register_backend(const char *name, const struct tevent_ops *ops)
+{
+	struct tevent_ops_list *e;
+
+	for (e = tevent_backends; e != NULL; e = e->next) {
+		if (0 == strcmp(e->name, name)) {
+			/* already registered, skip it */
+			return true;
+		}
+	}
+
+	e = talloc(NULL, struct tevent_ops_list);
+	if (e == NULL) return false;
+
+	e->name = name;
+	e->ops = ops;
+	DLIST_ADD(tevent_backends, e);
+
+	return true;
+}
+
+/*
+  set the default event backend
+ */
+void tevent_set_default_backend(const char *backend)
+{
+	talloc_free(tevent_default_backend);
+	tevent_default_backend = talloc_strdup(NULL, backend);
+}
+
+/*
+  initialise backends if not already done
+*/
+static void tevent_backend_init(void)
+{
+	static bool done;
+
+	if (done) {
+		return;
+	}
+
+	done = true;
+
+	tevent_poll_init();
+	tevent_poll_mt_init();
+#if defined(HAVE_EPOLL)
+	tevent_epoll_init();
+#elif defined(HAVE_SOLARIS_PORTS)
+	tevent_port_init();
+#endif
+
+	tevent_standard_init();
+}
+
+_PRIVATE_ const struct tevent_ops *tevent_find_ops_byname(const char *name)
+{
+	struct tevent_ops_list *e;
+
+	tevent_backend_init();
+
+	if (name == NULL) {
+		name = tevent_default_backend;
+	}
+	if (name == NULL) {
+		name = "standard";
+	}
+
+	for (e = tevent_backends; e != NULL; e = e->next) {
+		if (0 == strcmp(e->name, name)) {
+			return e->ops;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+  list available backends
+*/
+const char **tevent_backend_list(TALLOC_CTX *mem_ctx)
+{
+	const char **list = NULL;
+	struct tevent_ops_list *e;
+	size_t idx = 0;
+
+	tevent_backend_init();
+
+	for (e=tevent_backends;e;e=e->next) {
+		idx += 1;
+	}
+
+	list = talloc_zero_array(mem_ctx, const char *, idx+1);
+	if (list == NULL) {
+		return NULL;
+	}
+
+	idx = 0;
+	for (e=tevent_backends;e;e=e->next) {
+		list[idx] = talloc_strdup(list, e->name);
+		if (list[idx] == NULL) {
+			TALLOC_FREE(list);
+			return NULL;
+		}
+		idx += 1;
+	}
+
+	return list;
+}
+
+static void tevent_common_wakeup_fini(struct tevent_context *ev);
+
+#ifdef HAVE_PTHREAD
+
+static pthread_mutex_t tevent_contexts_mutex = PTHREAD_MUTEX_INITIALIZER;
+static struct tevent_context *tevent_contexts = NULL;
+static pthread_once_t tevent_atfork_initialized = PTHREAD_ONCE_INIT;
+static pid_t tevent_cached_global_pid = 0;
+
+static void tevent_atfork_prepare(void)
+{
+	struct tevent_context *ev;
+	int ret;
+
+	ret = pthread_mutex_lock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		abort();
+	}
+
+	for (ev = tevent_contexts; ev != NULL; ev = ev->next) {
+		struct tevent_threaded_context *tctx;
+
+		for (tctx = ev->threaded_contexts; tctx != NULL;
+		     tctx = tctx->next) {
+			ret = pthread_mutex_lock(&tctx->event_ctx_mutex);
+			if (ret != 0) {
+				tevent_abort(ev, "pthread_mutex_lock failed");
+			}
+		}
+
+		ret = pthread_mutex_lock(&ev->scheduled_mutex);
+		if (ret != 0) {
+			tevent_abort(ev, "pthread_mutex_lock failed");
+		}
+	}
+}
+
+static void tevent_atfork_parent(void)
+{
+	struct tevent_context *ev;
+	int ret;
+
+	for (ev = DLIST_TAIL(tevent_contexts); ev != NULL;
+	     ev = DLIST_PREV(ev)) {
+		struct tevent_threaded_context *tctx;
+
+		ret = pthread_mutex_unlock(&ev->scheduled_mutex);
+		if (ret != 0) {
+			tevent_abort(ev, "pthread_mutex_unlock failed");
+		}
+
+		for (tctx = DLIST_TAIL(ev->threaded_contexts); tctx != NULL;
+		     tctx = DLIST_PREV(tctx)) {
+			ret = pthread_mutex_unlock(&tctx->event_ctx_mutex);
+			if (ret != 0) {
+				tevent_abort(
+					ev, "pthread_mutex_unlock failed");
+			}
+		}
+	}
+
+	ret = pthread_mutex_unlock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		abort();
+	}
+}
+
+static void tevent_atfork_child(void)
+{
+	struct tevent_context *ev;
+	int ret;
+
+	tevent_cached_global_pid = getpid();
+
+	for (ev = DLIST_TAIL(tevent_contexts); ev != NULL;
+	     ev = DLIST_PREV(ev)) {
+		struct tevent_threaded_context *tctx;
+
+		for (tctx = DLIST_TAIL(ev->threaded_contexts); tctx != NULL;
+		     tctx = DLIST_PREV(tctx)) {
+			tctx->event_ctx = NULL;
+
+			ret = pthread_mutex_unlock(&tctx->event_ctx_mutex);
+			if (ret != 0) {
+				tevent_abort(
+					ev, "pthread_mutex_unlock failed");
+			}
+		}
+
+		ev->threaded_contexts = NULL;
+
+		ret = pthread_mutex_unlock(&ev->scheduled_mutex);
+		if (ret != 0) {
+			tevent_abort(ev, "pthread_mutex_unlock failed");
+		}
+	}
+
+	ret = pthread_mutex_unlock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		abort();
+	}
+}
+
+static void tevent_prep_atfork(void)
+{
+	int ret;
+
+	ret = pthread_atfork(tevent_atfork_prepare,
+			     tevent_atfork_parent,
+			     tevent_atfork_child);
+	if (ret != 0) {
+		abort();
+	}
+
+	tevent_cached_global_pid = getpid();
+}
+
+#endif
+
+static int tevent_init_globals(void)
+{
+#ifdef HAVE_PTHREAD
+	int ret;
+
+	ret = pthread_once(&tevent_atfork_initialized, tevent_prep_atfork);
+	if (ret != 0) {
+		return ret;
+	}
+#endif
+
+	return 0;
+}
+
+_PUBLIC_ pid_t tevent_cached_getpid(void)
+{
+#ifdef HAVE_PTHREAD
+	tevent_init_globals();
+#ifdef TEVENT_VERIFY_CACHED_GETPID
+	if (tevent_cached_global_pid != getpid()) {
+		tevent_abort(NULL, "tevent_cached_global_pid invalid");
+	}
+#endif
+	if (tevent_cached_global_pid != 0) {
+		return tevent_cached_global_pid;
+	}
+#endif
+	return getpid();
+}
+
+int tevent_common_context_destructor(struct tevent_context *ev)
+{
+	struct tevent_fd *fd, *fn;
+	struct tevent_timer *te, *tn;
+	struct tevent_immediate *ie, *in;
+	struct tevent_signal *se, *sn;
+	struct tevent_wrapper_glue *gl, *gn;
+#ifdef HAVE_PTHREAD
+	int ret;
+#endif
+
+	if (ev->wrapper.glue != NULL) {
+		tevent_abort(ev,
+			"tevent_common_context_destructor() active on wrapper");
+	}
+
+#ifdef HAVE_PTHREAD
+	ret = pthread_mutex_lock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		abort();
+	}
+
+	DLIST_REMOVE(tevent_contexts, ev);
+
+	ret = pthread_mutex_unlock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		abort();
+	}
+
+	while (ev->threaded_contexts != NULL) {
+		struct tevent_threaded_context *tctx = ev->threaded_contexts;
+
+		ret = pthread_mutex_lock(&tctx->event_ctx_mutex);
+		if (ret != 0) {
+			abort();
+		}
+
+		/*
+		 * Indicate to the thread that the tevent_context is
+		 * gone. The counterpart of this is in
+		 * _tevent_threaded_schedule_immediate, there we read
+		 * this under the threaded_context's mutex.
+		 */
+
+		tctx->event_ctx = NULL;
+
+		ret = pthread_mutex_unlock(&tctx->event_ctx_mutex);
+		if (ret != 0) {
+			abort();
+		}
+
+		DLIST_REMOVE(ev->threaded_contexts, tctx);
+	}
+
+	ret = pthread_mutex_destroy(&ev->scheduled_mutex);
+	if (ret != 0) {
+		abort();
+	}
+#endif
+
+	for (gl = ev->wrapper.list; gl; gl = gn) {
+		gn = gl->next;
+
+		gl->main_ev = NULL;
+		DLIST_REMOVE(ev->wrapper.list, gl);
+	}
+
+	tevent_common_wakeup_fini(ev);
+
+	for (fd = ev->fd_events; fd; fd = fn) {
+		fn = fd->next;
+		tevent_trace_fd_callback(fd->event_ctx, fd, TEVENT_EVENT_TRACE_DETACH);
+		fd->wrapper = NULL;
+		fd->event_ctx = NULL;
+		DLIST_REMOVE(ev->fd_events, fd);
+	}
+
+	ev->last_zero_timer = NULL;
+	for (te = ev->timer_events; te; te = tn) {
+		tn = te->next;
+		tevent_trace_timer_callback(te->event_ctx, te, TEVENT_EVENT_TRACE_DETACH);
+		te->wrapper = NULL;
+		te->event_ctx = NULL;
+		DLIST_REMOVE(ev->timer_events, te);
+	}
+
+	for (ie = ev->immediate_events; ie; ie = in) {
+		in = ie->next;
+		tevent_trace_immediate_callback(ie->event_ctx, ie, TEVENT_EVENT_TRACE_DETACH);
+		ie->wrapper = NULL;
+		ie->event_ctx = NULL;
+		ie->cancel_fn = NULL;
+		DLIST_REMOVE(ev->immediate_events, ie);
+	}
+
+	for (se = ev->signal_events; se; se = sn) {
+		sn = se->next;
+		tevent_trace_signal_callback(se->event_ctx, se, TEVENT_EVENT_TRACE_DETACH);
+		se->wrapper = NULL;
+		se->event_ctx = NULL;
+		DLIST_REMOVE(ev->signal_events, se);
+		/*
+		 * This is important, Otherwise signals
+		 * are handled twice in child. eg, SIGHUP.
+		 * one added in parent, and another one in
+		 * the child. -- BoYang
+		 */
+		tevent_cleanup_pending_signal_handlers(se);
+	}
+
+	/* removing nesting hook or we get an abort when nesting is
+	 * not allowed. -- SSS
+	 * Note that we need to leave the allowed flag at its current
+	 * value, otherwise the use in tevent_re_initialise() will
+	 * leave the event context with allowed forced to false, which
+	 * will break users that expect nesting to be allowed
+	 */
+	ev->nesting.level = 0;
+	ev->nesting.hook_fn = NULL;
+	ev->nesting.hook_private = NULL;
+
+	return 0;
+}
+
+static int tevent_common_context_constructor(struct tevent_context *ev)
+{
+	int ret;
+
+	ret = tevent_init_globals();
+	if (ret != 0) {
+		return ret;
+	}
+
+#ifdef HAVE_PTHREAD
+
+	ret = pthread_mutex_init(&ev->scheduled_mutex, NULL);
+	if (ret != 0) {
+		return ret;
+	}
+
+	ret = pthread_mutex_lock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		pthread_mutex_destroy(&ev->scheduled_mutex);
+		return ret;
+	}
+
+	DLIST_ADD(tevent_contexts, ev);
+
+	ret = pthread_mutex_unlock(&tevent_contexts_mutex);
+	if (ret != 0) {
+		abort();
+	}
+#endif
+
+	talloc_set_destructor(ev, tevent_common_context_destructor);
+
+	return 0;
+}
+
+void tevent_common_check_double_free(TALLOC_CTX *ptr, const char *reason)
+{
+	void *parent_ptr = talloc_parent(ptr);
+	size_t parent_blocks = talloc_total_blocks(parent_ptr);
+
+	if (parent_ptr != NULL && parent_blocks == 0) {
+		/*
+		 * This is an implicit talloc free, as we still have a parent
+		 * but it's already being destroyed. Note that
+		 * talloc_total_blocks(ptr) also just returns 0 if a
+		 * talloc_free(ptr) is still in progress of freeing all
+		 * children.
+		 */
+		return;
+	}
+
+	tevent_abort(NULL, reason);
+}
+
+/*
+  create a event_context structure for a specific implemementation.
+  This must be the first events call, and all subsequent calls pass
+  this event_context as the first element. Event handlers also
+  receive this as their first argument.
+
+  This function is for allowing third-party-applications to hook in gluecode
+  to their own event loop code, so that they can make async usage of our client libs
+
+  NOTE: use tevent_context_init() inside of samba!
+*/
+struct tevent_context *tevent_context_init_ops(TALLOC_CTX *mem_ctx,
+					       const struct tevent_ops *ops,
+					       void *additional_data)
+{
+	struct tevent_context *ev;
+	int ret;
+
+	ev = talloc_zero(mem_ctx, struct tevent_context);
+	if (!ev) return NULL;
+
+	ret = tevent_common_context_constructor(ev);
+	if (ret != 0) {
+		talloc_free(ev);
+		return NULL;
+	}
+
+	ev->ops = ops;
+	ev->additional_data = additional_data;
+
+	ret = ev->ops->context_init(ev);
+	if (ret != 0) {
+		talloc_free(ev);
+		return NULL;
+	}
+
+	return ev;
+}
+
+/*
+  create a event_context structure. This must be the first events
+  call, and all subsequent calls pass this event_context as the first
+  element. Event handlers also receive this as their first argument.
+*/
+struct tevent_context *tevent_context_init_byname(TALLOC_CTX *mem_ctx,
+						  const char *name)
+{
+	const struct tevent_ops *ops;
+
+	ops = tevent_find_ops_byname(name);
+	if (ops == NULL) {
+		return NULL;
+	}
+
+	return tevent_context_init_ops(mem_ctx, ops, NULL);
+}
+
+
+/*
+  create a event_context structure. This must be the first events
+  call, and all subsequent calls pass this event_context as the first
+  element. Event handlers also receive this as their first argument.
+*/
+struct tevent_context *tevent_context_init(TALLOC_CTX *mem_ctx)
+{
+	return tevent_context_init_byname(mem_ctx, NULL);
+}
+
+/*
+  add a fd based event
+  return NULL on failure (memory allocation error)
+*/
+struct tevent_fd *_tevent_add_fd(struct tevent_context *ev,
+				 TALLOC_CTX *mem_ctx,
+				 int fd,
+				 uint16_t flags,
+				 tevent_fd_handler_t handler,
+				 void *private_data,
+				 const char *handler_name,
+				 const char *location)
+{
+	return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data,
+			       handler_name, location);
+}
+
+/*
+  set a close function on the fd event
+*/
+void tevent_fd_set_close_fn(struct tevent_fd *fde,
+			    tevent_fd_close_fn_t close_fn)
+{
+	if (!fde) return;
+	if (!fde->event_ctx) return;
+	fde->event_ctx->ops->set_fd_close_fn(fde, close_fn);
+}
+
+static void tevent_fd_auto_close_fn(struct tevent_context *ev,
+				    struct tevent_fd *fde,
+				    int fd,
+				    void *private_data)
+{
+	close(fd);
+}
+
+void tevent_fd_set_auto_close(struct tevent_fd *fde)
+{
+	tevent_fd_set_close_fn(fde, tevent_fd_auto_close_fn);
+}
+
+/*
+  return the fd event flags
+*/
+uint16_t tevent_fd_get_flags(struct tevent_fd *fde)
+{
+	if (!fde) return 0;
+	if (!fde->event_ctx) return 0;
+	return fde->event_ctx->ops->get_fd_flags(fde);
+}
+
+/*
+  set the fd event flags
+*/
+void tevent_fd_set_flags(struct tevent_fd *fde, uint16_t flags)
+{
+	if (!fde) return;
+	if (!fde->event_ctx) return;
+	fde->event_ctx->ops->set_fd_flags(fde, flags);
+}
+
+bool tevent_signal_support(struct tevent_context *ev)
+{
+	if (ev->ops->add_signal) {
+		return true;
+	}
+	return false;
+}
+
+static void (*tevent_abort_fn)(const char *reason);
+
+void tevent_set_abort_fn(void (*abort_fn)(const char *reason))
+{
+	tevent_abort_fn = abort_fn;
+}
+
+void tevent_abort(struct tevent_context *ev, const char *reason)
+{
+	if (ev != NULL) {
+		tevent_debug(ev, TEVENT_DEBUG_FATAL,
+			     "abort: %s\n", reason);
+	}
+
+	if (!tevent_abort_fn) {
+		abort();
+	}
+
+	tevent_abort_fn(reason);
+}
+
+/*
+  add a timer event
+  return NULL on failure
+*/
+struct tevent_timer *_tevent_add_timer(struct tevent_context *ev,
+				       TALLOC_CTX *mem_ctx,
+				       struct timeval next_event,
+				       tevent_timer_handler_t handler,
+				       void *private_data,
+				       const char *handler_name,
+				       const char *location)
+{
+	return ev->ops->add_timer(ev, mem_ctx, next_event, handler, private_data,
+				  handler_name, location);
+}
+
+/*
+  allocate an immediate event
+  return NULL on failure (memory allocation error)
+*/
+struct tevent_immediate *_tevent_create_immediate(TALLOC_CTX *mem_ctx,
+						  const char *location)
+{
+	struct tevent_immediate *im;
+
+	im = talloc(mem_ctx, struct tevent_immediate);
+	if (im == NULL) return NULL;
+
+	*im = (struct tevent_immediate) { .create_location = location };
+
+	return im;
+}
+
+/*
+  schedule an immediate event
+*/
+void _tevent_schedule_immediate(struct tevent_immediate *im,
+				struct tevent_context *ev,
+				tevent_immediate_handler_t handler,
+				void *private_data,
+				const char *handler_name,
+				const char *location)
+{
+	ev->ops->schedule_immediate(im, ev, handler, private_data,
+				    handler_name, location);
+}
+
+/*
+  add a signal event
+
+  sa_flags are flags to sigaction(2)
+
+  return NULL on failure
+*/
+struct tevent_signal *_tevent_add_signal(struct tevent_context *ev,
+					 TALLOC_CTX *mem_ctx,
+					 int signum,
+					 int sa_flags,
+					 tevent_signal_handler_t handler,
+					 void *private_data,
+					 const char *handler_name,
+					 const char *location)
+{
+	return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data,
+				   handler_name, location);
+}
+
+void tevent_loop_allow_nesting(struct tevent_context *ev)
+{
+	if (ev->wrapper.glue != NULL) {
+		tevent_abort(ev, "tevent_loop_allow_nesting() on wrapper");
+		return;
+	}
+
+	if (ev->wrapper.list != NULL) {
+		tevent_abort(ev, "tevent_loop_allow_nesting() with wrapper");
+		return;
+	}
+
+	ev->nesting.allowed = true;
+}
+
+void tevent_loop_set_nesting_hook(struct tevent_context *ev,
+				  tevent_nesting_hook hook,
+				  void *private_data)
+{
+	if (ev->nesting.hook_fn && 
+	    (ev->nesting.hook_fn != hook ||
+	     ev->nesting.hook_private != private_data)) {
+		/* the way the nesting hook code is currently written
+		   we cannot support two different nesting hooks at the
+		   same time. */
+		tevent_abort(ev, "tevent: Violation of nesting hook rules\n");
+	}
+	ev->nesting.hook_fn = hook;
+	ev->nesting.hook_private = private_data;
+}
+
+static void tevent_abort_nesting(struct tevent_context *ev, const char *location)
+{
+	const char *reason;
+
+	reason = talloc_asprintf(NULL, "tevent_loop_once() nesting at %s",
+				 location);
+	if (!reason) {
+		reason = "tevent_loop_once() nesting";
+	}
+
+	tevent_abort(ev, reason);
+}
+
+/*
+  do a single event loop using the events defined in ev 
+*/
+int _tevent_loop_once(struct tevent_context *ev, const char *location)
+{
+	int ret;
+	void *nesting_stack_ptr = NULL;
+
+	ev->nesting.level++;
+
+	if (ev->nesting.level > 1) {
+		if (!ev->nesting.allowed) {
+			tevent_abort_nesting(ev, location);
+			errno = ELOOP;
+			return -1;
+		}
+	}
+	if (ev->nesting.level > 0) {
+		if (ev->nesting.hook_fn) {
+			int ret2;
+			ret2 = ev->nesting.hook_fn(ev,
+						   ev->nesting.hook_private,
+						   ev->nesting.level,
+						   true,
+						   (void *)&nesting_stack_ptr,
+						   location);
+			if (ret2 != 0) {
+				ret = ret2;
+				goto done;
+			}
+		}
+	}
+
+	tevent_trace_point_callback(ev, TEVENT_TRACE_BEFORE_LOOP_ONCE);
+	ret = ev->ops->loop_once(ev, location);
+	tevent_trace_point_callback(ev, TEVENT_TRACE_AFTER_LOOP_ONCE);
+
+	if (ev->nesting.level > 0) {
+		if (ev->nesting.hook_fn) {
+			int ret2;
+			ret2 = ev->nesting.hook_fn(ev,
+						   ev->nesting.hook_private,
+						   ev->nesting.level,
+						   false,
+						   (void *)&nesting_stack_ptr,
+						   location);
+			if (ret2 != 0) {
+				ret = ret2;
+				goto done;
+			}
+		}
+	}
+
+done:
+	ev->nesting.level--;
+	return ret;
+}
+
+/*
+  this is a performance optimization for the samba4 nested event loop problems
+*/
+int _tevent_loop_until(struct tevent_context *ev,
+		       bool (*finished)(void *private_data),
+		       void *private_data,
+		       const char *location)
+{
+	int ret = 0;
+	void *nesting_stack_ptr = NULL;
+
+	ev->nesting.level++;
+
+	if (ev->nesting.level > 1) {
+		if (!ev->nesting.allowed) {
+			tevent_abort_nesting(ev, location);
+			errno = ELOOP;
+			return -1;
+		}
+	}
+	if (ev->nesting.level > 0) {
+		if (ev->nesting.hook_fn) {
+			int ret2;
+			ret2 = ev->nesting.hook_fn(ev,
+						   ev->nesting.hook_private,
+						   ev->nesting.level,
+						   true,
+						   (void *)&nesting_stack_ptr,
+						   location);
+			if (ret2 != 0) {
+				ret = ret2;
+				goto done;
+			}
+		}
+	}
+
+	while (!finished(private_data)) {
+		tevent_trace_point_callback(ev, TEVENT_TRACE_BEFORE_LOOP_ONCE);
+		ret = ev->ops->loop_once(ev, location);
+		tevent_trace_point_callback(ev, TEVENT_TRACE_AFTER_LOOP_ONCE);
+		if (ret != 0) {
+			break;
+		}
+	}
+
+	if (ev->nesting.level > 0) {
+		if (ev->nesting.hook_fn) {
+			int ret2;
+			ret2 = ev->nesting.hook_fn(ev,
+						   ev->nesting.hook_private,
+						   ev->nesting.level,
+						   false,
+						   (void *)&nesting_stack_ptr,
+						   location);
+			if (ret2 != 0) {
+				ret = ret2;
+				goto done;
+			}
+		}
+	}
+
+done:
+	ev->nesting.level--;
+	return ret;
+}
+
+bool tevent_common_have_events(struct tevent_context *ev)
+{
+	if (ev->fd_events != NULL) {
+		if (ev->fd_events != ev->wakeup_fde) {
+			return true;
+		}
+		if (ev->fd_events->next != NULL) {
+			return true;
+		}
+
+		/*
+		 * At this point we just have the wakeup pipe event as
+		 * the only fd_event. That one does not count as a
+		 * regular event, so look at the other event types.
+		 */
+	}
+
+	return ((ev->timer_events != NULL) ||
+		(ev->immediate_events != NULL) ||
+		(ev->signal_events != NULL));
+}
+
+/*
+  return on failure or (with 0) if all fd events are removed
+*/
+int tevent_common_loop_wait(struct tevent_context *ev,
+			    const char *location)
+{
+	/*
+	 * loop as long as we have events pending
+	 */
+	while (tevent_common_have_events(ev)) {
+		int ret;
+		ret = _tevent_loop_once(ev, location);
+		if (ret != 0) {
+			tevent_debug(ev, TEVENT_DEBUG_FATAL,
+				     "_tevent_loop_once() failed: %d - %s\n",
+				     ret, strerror(errno));
+			return ret;
+		}
+	}
+
+	tevent_debug(ev, TEVENT_DEBUG_WARNING,
+		     "tevent_common_loop_wait() out of events\n");
+	return 0;
+}
+
+/*
+  return on failure or (with 0) if all fd events are removed
+*/
+int _tevent_loop_wait(struct tevent_context *ev, const char *location)
+{
+	return ev->ops->loop_wait(ev, location);
+}
+
+
+/*
+  re-initialise a tevent context. This leaves you with the same
+  event context, but all events are wiped and the structure is
+  re-initialised. This is most useful after a fork()  
+
+  zero is returned on success, non-zero on failure
+*/
+int tevent_re_initialise(struct tevent_context *ev)
+{
+	tevent_common_context_destructor(ev);
+
+	tevent_common_context_constructor(ev);
+
+	return ev->ops->context_init(ev);
+}
+
+static void wakeup_pipe_handler(struct tevent_context *ev,
+				struct tevent_fd *fde,
+				uint16_t flags, void *_private)
+{
+	ssize_t ret;
+
+	do {
+		/*
+		 * This is the boilerplate for eventfd, but it works
+		 * for pipes too. And as we don't care about the data
+		 * we read, we're fine.
+		 */
+		uint64_t val;
+		ret = read(fde->fd, &val, sizeof(val));
+	} while (ret == -1 && errno == EINTR);
+}
+
+/*
+ * Initialize the wakeup pipe and pipe fde
+ */
+
+int tevent_common_wakeup_init(struct tevent_context *ev)
+{
+	int ret, read_fd;
+
+	if (ev->wakeup_fde != NULL) {
+		return 0;
+	}
+
+#ifdef HAVE_EVENTFD
+	ret = eventfd(0, EFD_NONBLOCK);
+	if (ret == -1) {
+		return errno;
+	}
+	read_fd = ev->wakeup_fd = ret;
+#else
+	{
+		int pipe_fds[2];
+		ret = pipe(pipe_fds);
+		if (ret == -1) {
+			return errno;
+		}
+		ev->wakeup_fd = pipe_fds[1];
+		ev->wakeup_read_fd = pipe_fds[0];
+
+		ev_set_blocking(ev->wakeup_fd, false);
+		ev_set_blocking(ev->wakeup_read_fd, false);
+
+		read_fd = ev->wakeup_read_fd;
+	}
+#endif
+
+	ev->wakeup_fde = tevent_add_fd(ev, ev, read_fd, TEVENT_FD_READ,
+				     wakeup_pipe_handler, NULL);
+	if (ev->wakeup_fde == NULL) {
+		close(ev->wakeup_fd);
+#ifndef HAVE_EVENTFD
+		close(ev->wakeup_read_fd);
+#endif
+		return ENOMEM;
+	}
+
+	return 0;
+}
+
+int tevent_common_wakeup_fd(int fd)
+{
+	ssize_t ret;
+
+	do {
+#ifdef HAVE_EVENTFD
+		uint64_t val = 1;
+		ret = write(fd, &val, sizeof(val));
+#else
+		char c = '\0';
+		ret = write(fd, &c, 1);
+#endif
+	} while ((ret == -1) && (errno == EINTR));
+
+	return 0;
+}
+
+int tevent_common_wakeup(struct tevent_context *ev)
+{
+	if (ev->wakeup_fde == NULL) {
+		return ENOTCONN;
+	}
+
+	return tevent_common_wakeup_fd(ev->wakeup_fd);
+}
+
+static void tevent_common_wakeup_fini(struct tevent_context *ev)
+{
+	if (ev->wakeup_fde == NULL) {
+		return;
+	}
+
+	TALLOC_FREE(ev->wakeup_fde);
+
+	close(ev->wakeup_fd);
+#ifndef HAVE_EVENTFD
+	close(ev->wakeup_read_fd);
+#endif
+}