Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream

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

1 files changed, 1389 insertions, 0 deletions

diff --git a/src/lib/ioloop.c b/src/lib/ioloop.c
new file mode 100644
index 0000000..e248808
--- /dev/null
+++ b/src/lib/ioloop.c
@@ -0,0 +1,1389 @@
+/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "array.h"
+#include "backtrace-string.h"
+#include "llist.h"
+#include "time-util.h"
+#include "istream-private.h"
+#include "ioloop-private.h"
+
+#include <unistd.h>
+
+/* Dovecot attempts to detect also when time suddenly jumps forwards.
+   This is done by getting the minimum timeout wait in epoll() (or similar)
+   and then seeing if the current time after epoll() is past the timeout.
+   This can't be very exact, so likely the difference is always at least
+   1 microsecond. In high load situations it can be somewhat higher.
+   Dovecot generally doesn't have very important short timeouts, so to avoid
+   logging many warnings about this, use a rather high value. */
+#define IOLOOP_TIME_MOVED_FORWARDS_MIN_USECS (100000)
+
+time_t ioloop_time = 0;
+struct timeval ioloop_timeval;
+struct ioloop *current_ioloop = NULL;
+uint64_t ioloop_global_wait_usecs = 0;
+
+static ARRAY(io_switch_callback_t *) io_switch_callbacks = ARRAY_INIT;
+static ARRAY(io_destroy_callback_t *) io_destroy_callbacks = ARRAY_INIT;
+static bool panic_on_leak = FALSE, panic_on_leak_set = FALSE;
+
+static time_t data_stack_last_free_unused = 0;
+
+static void io_loop_initialize_handler(struct ioloop *ioloop)
+{
+	unsigned int initial_fd_count;
+
+	initial_fd_count = ioloop->max_fd_count > 0 &&
+		ioloop->max_fd_count < IOLOOP_INITIAL_FD_COUNT ?
+		ioloop->max_fd_count : IOLOOP_INITIAL_FD_COUNT;
+	io_loop_handler_init(ioloop, initial_fd_count);
+}
+
+static struct io_file *
+io_add_file(struct ioloop *ioloop, int fd, enum io_condition condition,
+	    const char *source_filename,
+	    unsigned int source_linenum,
+	    io_callback_t *callback, void *context)
+{
+	struct io_file *io;
+
+	i_assert(callback != NULL);
+	i_assert((condition & IO_NOTIFY) == 0);
+
+	io = i_new(struct io_file, 1);
+        io->io.condition = condition;
+	io->io.callback = callback;
+        io->io.context = context;
+	io->io.ioloop = ioloop;
+	io->io.source_filename = source_filename;
+	io->io.source_linenum = source_linenum;
+	io->refcount = 1;
+	io->fd = fd;
+
+	if (io->io.ioloop->cur_ctx != NULL) {
+		io->io.ctx = io->io.ioloop->cur_ctx;
+		io_loop_context_ref(io->io.ctx);
+	}
+
+	if (io->io.ioloop->handler_context == NULL)
+		io_loop_initialize_handler(io->io.ioloop);
+	if (fd != -1)
+		io_loop_handle_add(io);
+	else {
+		/* we're adding an istream whose only way to get notified
+		   is to call i_stream_set_input_pending() */
+	}
+
+	if (io->io.ioloop->io_files != NULL) {
+		io->io.ioloop->io_files->prev = io;
+		io->next = io->io.ioloop->io_files;
+	}
+	io->io.ioloop->io_files = io;
+	return io;
+}
+
+#undef io_add_to
+struct io *io_add_to(struct ioloop *ioloop, int fd, enum io_condition condition,
+		     const char *source_filename, unsigned int source_linenum,
+		     io_callback_t *callback, void *context)
+{
+	struct io_file *io;
+
+	i_assert(fd >= 0);
+	io = io_add_file(ioloop, fd, condition,
+			 source_filename, source_linenum,
+			 callback, context);
+	return &io->io;
+}
+
+#undef io_add
+struct io *io_add(int fd, enum io_condition condition,
+		  const char *source_filename,
+		  unsigned int source_linenum,
+		  io_callback_t *callback, void *context)
+{
+	return io_add_to(current_ioloop, fd, condition,
+			 source_filename, source_linenum,
+			 callback, context);
+}
+
+#undef io_add_istream_to
+struct io *io_add_istream_to(struct ioloop *ioloop, struct istream *input,
+			     const char *source_filename,
+			     unsigned int source_linenum,
+			     io_callback_t *callback, void *context)
+{
+	struct io_file *io;
+
+	io = io_add_file(ioloop, i_stream_get_fd(input), IO_READ,
+			 source_filename, source_linenum, callback, context);
+	io->istream = input;
+	i_stream_ref(io->istream);
+	i_stream_set_io(io->istream, &io->io);
+	return &io->io;
+}
+
+#undef io_add_istream
+struct io *io_add_istream(struct istream *input, const char *source_filename,
+			  unsigned int source_linenum,
+			  io_callback_t *callback, void *context)
+{
+	return io_add_istream_to(current_ioloop, input,
+				 source_filename, source_linenum,
+				 callback, context);
+}
+
+static void io_file_unlink(struct io_file *io)
+{
+	if (io->prev != NULL)
+		io->prev->next = io->next;
+	else
+		io->io.ioloop->io_files = io->next;
+
+	if (io->next != NULL)
+		io->next->prev = io->prev;
+
+	/* if we got here from an I/O handler callback, make sure we
+	   don't try to handle this one next. */
+	if (io->io.ioloop->next_io_file == io)
+		io->io.ioloop->next_io_file = io->next;
+}
+
+static void io_remove_full(struct io **_io, bool closed)
+{
+	struct io *io = *_io;
+
+	i_assert(io->callback != NULL);
+
+	*_io = NULL;
+
+	/* make sure the callback doesn't get called anymore.
+	   kqueue code relies on this. */
+	io->callback = NULL;
+
+	if (io->pending) {
+		i_assert(io->ioloop->io_pending_count > 0);
+		io->ioloop->io_pending_count--;
+	}
+
+	if (io->ctx != NULL)
+		io_loop_context_unref(&io->ctx);
+
+	if ((io->condition & IO_NOTIFY) != 0)
+		io_loop_notify_remove(io);
+	else {
+		struct io_file *io_file = (struct io_file *)io;
+		struct istream *istream = io_file->istream;
+
+		if (istream != NULL) {
+			/* remove io before it's freed */
+			i_stream_unset_io(istream, io);
+		}
+
+		io_file_unlink(io_file);
+		if (io_file->fd != -1)
+			io_loop_handle_remove(io_file, closed);
+		else
+			i_free(io);
+
+		/* remove io from the ioloop before unreferencing the istream,
+		   because a destroyed istream may automatically close the
+		   fd. */
+		i_stream_unref(&istream);
+	}
+}
+
+void io_remove(struct io **io)
+{
+	if (*io == NULL)
+		return;
+
+	io_remove_full(io, FALSE);
+}
+
+void io_remove_closed(struct io **io)
+{
+	if (*io == NULL)
+		return;
+
+	i_assert(((*io)->condition & IO_NOTIFY) == 0);
+
+	io_remove_full(io, TRUE);
+}
+
+void io_set_pending(struct io *io)
+{
+	i_assert((io->condition & IO_NOTIFY) == 0);
+
+	if (!io->pending) {
+		io->pending = TRUE;
+		io->ioloop->io_pending_count++;
+	}
+}
+
+bool io_is_pending(struct io *io)
+{
+	return io->pending;
+}
+
+void io_set_never_wait_alone(struct io *io, bool set)
+{
+	io->never_wait_alone = set;
+}
+
+static void timeout_update_next(struct timeout *timeout, struct timeval *tv_now)
+{
+	if (tv_now == NULL)
+		i_gettimeofday(&timeout->next_run);
+	else {
+		timeout->next_run.tv_sec = tv_now->tv_sec;
+                timeout->next_run.tv_usec = tv_now->tv_usec;
+	}
+
+	/* we don't want microsecond accuracy or this function will be
+	   called all the time - millisecond is more than enough */
+	timeout->next_run.tv_usec -= timeout->next_run.tv_usec % 1000;
+
+	timeout->next_run.tv_sec += timeout->msecs/1000;
+	timeout->next_run.tv_usec += (timeout->msecs%1000)*1000;
+
+	if (timeout->next_run.tv_usec >= 1000000) {
+                timeout->next_run.tv_sec++;
+                timeout->next_run.tv_usec -= 1000000;
+	}
+}
+
+static struct timeout *
+timeout_add_common(struct ioloop *ioloop, const char *source_filename,
+		   unsigned int source_linenum,
+		   timeout_callback_t *callback, void *context)
+{
+	struct timeout *timeout;
+
+	timeout = i_new(struct timeout, 1);
+	timeout->item.idx = UINT_MAX;
+	timeout->source_filename = source_filename;
+	timeout->source_linenum = source_linenum;
+	timeout->ioloop = ioloop;
+
+	timeout->callback = callback;
+	timeout->context = context;
+
+	if (timeout->ioloop->cur_ctx != NULL) {
+		timeout->ctx = timeout->ioloop->cur_ctx;
+		io_loop_context_ref(timeout->ctx);
+	}
+
+	return timeout;
+}
+
+#undef timeout_add_to
+struct timeout *timeout_add_to(struct ioloop *ioloop, unsigned int msecs,
+			       const char *source_filename,
+			       unsigned int source_linenum,
+			       timeout_callback_t *callback, void *context)
+{
+	struct timeout *timeout;
+
+	timeout = timeout_add_common(ioloop, source_filename, source_linenum,
+				     callback, context);
+	timeout->msecs = msecs;
+
+	if (msecs > 0) {
+		/* start this timeout in the next run cycle */
+		array_push_back(&timeout->ioloop->timeouts_new, &timeout);
+	} else {
+		/* Trigger zero timeouts as soon as possible. When ioloop is
+		   running, refresh the timestamp to prevent infinite loops
+		   in case a timeout callback keeps recreating the 0-timeout. */
+		timeout_update_next(timeout, timeout->ioloop->running ?
+			    NULL : &ioloop_timeval);
+		priorityq_add(timeout->ioloop->timeouts, &timeout->item);
+	}
+	return timeout;
+}
+
+#undef timeout_add
+struct timeout *timeout_add(unsigned int msecs, const char *source_filename,
+			    unsigned int source_linenum,
+			    timeout_callback_t *callback, void *context)
+{
+	return timeout_add_to(current_ioloop, msecs,
+			      source_filename, source_linenum,
+			      callback, context);
+}
+
+#undef timeout_add_short_to
+struct timeout *
+timeout_add_short_to(struct ioloop *ioloop, unsigned int msecs,
+		     const char *source_filename, unsigned int source_linenum,
+		     timeout_callback_t *callback, void *context)
+{
+	return timeout_add_to(ioloop, msecs,
+			      source_filename, source_linenum,
+			      callback, context);
+}
+
+#undef timeout_add_short
+struct timeout *
+timeout_add_short(unsigned int msecs, const char *source_filename,
+		  unsigned int source_linenum,
+		  timeout_callback_t *callback, void *context)
+{
+	return timeout_add(msecs, source_filename, source_linenum,
+			   callback, context);
+}
+
+#undef timeout_add_absolute_to
+struct timeout *
+timeout_add_absolute_to(struct ioloop *ioloop, const struct timeval *time,
+			const char *source_filename,
+			unsigned int source_linenum,
+			timeout_callback_t *callback, void *context)
+{
+	struct timeout *timeout;
+
+	timeout = timeout_add_common(ioloop, source_filename, source_linenum,
+				     callback, context);
+	timeout->one_shot = TRUE;
+	timeout->next_run = *time;
+
+	priorityq_add(timeout->ioloop->timeouts, &timeout->item);
+	return timeout;
+}
+
+#undef timeout_add_absolute
+struct timeout *
+timeout_add_absolute(const struct timeval *time,
+		     const char *source_filename,
+		     unsigned int source_linenum,
+		     timeout_callback_t *callback, void *context)
+{
+	return timeout_add_absolute_to(current_ioloop, time,
+				       source_filename, source_linenum,
+				       callback, context);
+}
+
+static struct timeout *
+timeout_copy(const struct timeout *old_to, struct ioloop *ioloop)
+{
+	struct timeout *new_to;
+
+	new_to = timeout_add_common(ioloop,
+		old_to->source_filename, old_to->source_linenum,
+		old_to->callback, old_to->context);
+	new_to->one_shot = old_to->one_shot;
+	new_to->msecs = old_to->msecs;
+	new_to->next_run = old_to->next_run;
+
+	if (old_to->item.idx != UINT_MAX)
+		priorityq_add(new_to->ioloop->timeouts, &new_to->item);
+	else if (!new_to->one_shot) {
+		i_assert(new_to->msecs > 0);
+		array_push_back(&new_to->ioloop->timeouts_new, &new_to);
+	}
+
+	return new_to;
+}
+
+static void timeout_free(struct timeout *timeout)
+{
+	if (timeout->ctx != NULL)
+		io_loop_context_unref(&timeout->ctx);
+	i_free(timeout);
+}
+
+void timeout_remove(struct timeout **_timeout)
+{
+	struct timeout *timeout = *_timeout;
+	struct ioloop *ioloop;
+
+	if (timeout == NULL)
+		return;
+
+	ioloop = timeout->ioloop;
+
+	*_timeout = NULL;
+	if (timeout->item.idx != UINT_MAX)
+		priorityq_remove(timeout->ioloop->timeouts, &timeout->item);
+	else if (!timeout->one_shot && timeout->msecs > 0) {
+		struct timeout *const *to_idx;
+		array_foreach(&ioloop->timeouts_new, to_idx) {
+			if (*to_idx == timeout) {
+				array_delete(&ioloop->timeouts_new,
+					array_foreach_idx(&ioloop->timeouts_new, to_idx), 1);
+				break;
+			}
+		}
+	}
+	timeout_free(timeout);
+}
+
+static void ATTR_NULL(2)
+timeout_reset_timeval(struct timeout *timeout, struct timeval *tv_now)
+{
+	if (timeout->item.idx == UINT_MAX)
+		return;
+
+	timeout_update_next(timeout, tv_now);
+	/* If we came here from io_loop_handle_timeouts_real(), next_run must
+	   be larger than tv_now or it can go to infinite loop. This would
+	   mainly happen with 0 ms timeouts. Avoid this by making sure
+	   next_run is at least 1 us higher than tv_now.
+
+	   Note that some callers (like master process's process_min_avail
+	   preforking timeout) really do want the 0 ms timeout to trigger
+	   multiple times as rapidly as it can (but in separate ioloop runs).
+	   So don't increase it more than by 1 us. */
+	if (tv_now != NULL && timeval_cmp(&timeout->next_run, tv_now) <= 0) {
+		timeout->next_run = *tv_now;
+		timeval_add_usecs(&timeout->next_run, 1);
+	}
+	priorityq_remove(timeout->ioloop->timeouts, &timeout->item);
+	priorityq_add(timeout->ioloop->timeouts, &timeout->item);
+}
+
+void timeout_reset(struct timeout *timeout)
+{
+	i_assert(!timeout->one_shot);
+	timeout_reset_timeval(timeout, NULL);
+}
+
+static int timeout_get_wait_time(struct timeout *timeout, struct timeval *tv_r,
+				 struct timeval *tv_now, bool in_timeout_loop)
+{
+	int ret;
+
+	if (tv_now->tv_sec == 0)
+		i_gettimeofday(tv_now);
+	tv_r->tv_sec = tv_now->tv_sec;
+	tv_r->tv_usec = tv_now->tv_usec;
+
+	i_assert(tv_r->tv_sec > 0);
+	i_assert(timeout->next_run.tv_sec > 0);
+
+	tv_r->tv_sec = timeout->next_run.tv_sec - tv_r->tv_sec;
+	tv_r->tv_usec = timeout->next_run.tv_usec - tv_r->tv_usec;
+	if (tv_r->tv_usec < 0) {
+		tv_r->tv_sec--;
+		tv_r->tv_usec += 1000000;
+	}
+
+	if (tv_r->tv_sec < 0) {
+		/* The timeout should have been called already */
+		tv_r->tv_sec = 0;
+		tv_r->tv_usec = 0;
+		return 0;
+	}
+	if (tv_r->tv_sec == 0 && tv_r->tv_usec == 1 && !in_timeout_loop) {
+		/* Possibly 0 ms timeout. Don't wait for a full millisecond
+		   for it to trigger. */
+		tv_r->tv_usec = 0;
+		return 0;
+	}
+	if (tv_r->tv_sec > INT_MAX/1000-1)
+		tv_r->tv_sec = INT_MAX/1000-1;
+
+	/* round wait times up to next millisecond */
+	ret = tv_r->tv_sec * 1000 + (tv_r->tv_usec + 999) / 1000;
+	i_assert(ret >= 0 && tv_r->tv_sec >= 0 && tv_r->tv_usec >= 0);
+	return ret;
+}
+
+static int io_loop_get_wait_time(struct ioloop *ioloop, struct timeval *tv_r)
+{
+	struct timeval tv_now;
+	struct priorityq_item *item;
+	struct timeout *timeout;
+	int msecs;
+
+	item = priorityq_peek(ioloop->timeouts);
+	timeout = (struct timeout *)item;
+
+	/* we need to see if there are pending IO waiting,
+	   if there is, we set msecs = 0 to ensure they are
+	   processed without delay */
+	if (timeout == NULL && ioloop->io_pending_count == 0) {
+		/* no timeouts. use INT_MAX msecs for timeval and
+		   return -1 for poll/epoll infinity. */
+		tv_r->tv_sec = INT_MAX / 1000;
+		tv_r->tv_usec = 0;
+		ioloop->next_max_time.tv_sec = (1ULL << (TIME_T_MAX_BITS-1)) - 1;
+		ioloop->next_max_time.tv_usec = 0;
+		return -1;
+	}
+
+	if (ioloop->io_pending_count > 0) {
+		i_gettimeofday(&tv_now);
+		msecs = 0;
+		tv_r->tv_sec = 0;
+		tv_r->tv_usec = 0;
+	} else {
+		tv_now.tv_sec = 0;
+		msecs = timeout_get_wait_time(timeout, tv_r, &tv_now, FALSE);
+	}
+	ioloop->next_max_time = tv_now;
+	timeval_add_msecs(&ioloop->next_max_time, msecs);
+
+	/* update ioloop_timeval - this is meant for io_loop_handle_timeouts()'s
+	   ioloop_wait_usecs calculation. normally after this we go to the
+	   ioloop and after that we update ioloop_timeval immediately again. */
+	ioloop_timeval = tv_now;
+	ioloop_time = tv_now.tv_sec;
+	i_assert(msecs == 0 || timeout->msecs > 0 || timeout->one_shot);
+	return msecs;
+}
+
+static bool io_loop_have_waitable_io_files(struct ioloop *ioloop)
+{
+	struct io_file *io;
+
+	for (io = ioloop->io_files; io != NULL; io = io->next) {
+		if (io->io.callback != NULL && !io->io.never_wait_alone)
+			return TRUE;
+	}
+	return FALSE;
+}
+
+int io_loop_run_get_wait_time(struct ioloop *ioloop, struct timeval *tv_r)
+{
+	int msecs = io_loop_get_wait_time(ioloop, tv_r);
+	if (msecs < 0 && !io_loop_have_waitable_io_files(ioloop))
+		i_panic("BUG: No IOs or timeouts set. Not waiting for infinity.");
+	return msecs;
+}
+
+static int timeout_cmp(const void *p1, const void *p2)
+{
+	const struct timeout *to1 = p1, *to2 = p2;
+
+	return timeval_cmp(&to1->next_run, &to2->next_run);
+}
+
+static void
+io_loop_default_time_moved(const struct timeval *old_time,
+			   const struct timeval *new_time)
+{
+	long long diff = timeval_diff_usecs(old_time, new_time);
+	if (diff > 0) {
+		i_warning("Time moved backwards by %lld.%06lld seconds.",
+			  diff / 1000000, diff % 1000000);
+	}
+}
+
+static void io_loop_timeouts_start_new(struct ioloop *ioloop)
+{
+	struct timeout *timeout;
+
+	if (array_count(&ioloop->timeouts_new) == 0)
+		return;
+	
+	io_loop_time_refresh();
+
+	array_foreach_elem(&ioloop->timeouts_new, timeout) {
+		i_assert(timeout->next_run.tv_sec == 0 &&
+			timeout->next_run.tv_usec == 0);
+		i_assert(!timeout->one_shot);
+		i_assert(timeout->msecs > 0);
+		timeout_update_next(timeout, &ioloop_timeval);
+		priorityq_add(ioloop->timeouts, &timeout->item);
+	}
+	array_clear(&ioloop->timeouts_new);
+}
+
+static void io_loop_timeouts_update(struct ioloop *ioloop, long long diff_usecs)
+{
+	struct priorityq_item *const *items;
+	unsigned int i, count;
+
+	count = priorityq_count(ioloop->timeouts);
+	items = priorityq_items(ioloop->timeouts);
+	for (i = 0; i < count; i++) {
+		struct timeout *to = (struct timeout *)items[i];
+
+		if (diff_usecs > 0)
+			timeval_add_usecs(&to->next_run, diff_usecs);
+		else
+			timeval_sub_usecs(&to->next_run, -diff_usecs);
+	}
+}
+
+static void io_loops_timeouts_update(long long diff_usecs)
+{
+	struct ioloop *ioloop;
+
+	for (ioloop = current_ioloop; ioloop != NULL; ioloop = ioloop->prev)
+		io_loop_timeouts_update(ioloop, diff_usecs);
+}
+
+static void ioloop_add_wait_time(struct ioloop *ioloop)
+{
+	struct io_wait_timer *timer;
+	long long diff;
+
+	diff = timeval_diff_usecs(&ioloop_timeval, &ioloop->wait_started);
+	if (diff < 0) {
+		/* time moved backwards */
+		diff = 0;
+	}
+
+	ioloop->ioloop_wait_usecs += diff;
+	ioloop_global_wait_usecs += diff;
+
+	for (timer = ioloop->wait_timers; timer != NULL; timer = timer->next)
+		timer->usecs += diff;
+}
+
+static void io_loop_handle_timeouts_real(struct ioloop *ioloop)
+{
+	struct priorityq_item *item;
+	struct timeval tv_old, tv, tv_call;
+	long long diff_usecs;
+	data_stack_frame_t t_id;
+
+	tv_old = ioloop_timeval;
+	i_gettimeofday(&ioloop_timeval);
+
+	diff_usecs = timeval_diff_usecs(&ioloop_timeval, &tv_old);
+	if (unlikely(diff_usecs < 0)) {
+		/* time moved backwards */
+		io_loops_timeouts_update(diff_usecs);
+		ioloop->time_moved_callback(&tv_old, &ioloop_timeval);
+		i_assert(ioloop == current_ioloop);
+		/* the callback may have slept, so check the time again. */
+		i_gettimeofday(&ioloop_timeval);
+	} else {
+		diff_usecs = timeval_diff_usecs(&ioloop->next_max_time,
+						&ioloop_timeval);
+		if (unlikely(-diff_usecs >= IOLOOP_TIME_MOVED_FORWARDS_MIN_USECS)) {
+			io_loops_timeouts_update(-diff_usecs);
+			/* time moved forwards */
+			ioloop->time_moved_callback(&ioloop->next_max_time,
+						    &ioloop_timeval);
+			i_assert(ioloop == current_ioloop);
+		}
+		ioloop_add_wait_time(ioloop);
+	}
+
+	ioloop_time = ioloop_timeval.tv_sec;
+	tv_call = ioloop_timeval;
+
+	while (ioloop->running &&
+	       (item = priorityq_peek(ioloop->timeouts)) != NULL) {
+		struct timeout *timeout = (struct timeout *)item;
+
+		/* use tv_call to make sure we don't get to infinite loop in
+		   case callbacks update ioloop_timeval. */
+		if (timeout_get_wait_time(timeout, &tv, &tv_call, TRUE) > 0)
+			break;
+
+		if (timeout->one_shot) {
+			/* remove timeout from queue */
+			priorityq_remove(timeout->ioloop->timeouts, &timeout->item);
+		} else {
+			/* update timeout's next_run and reposition it in the queue */
+			timeout_reset_timeval(timeout, &tv_call);
+		}
+
+		if (timeout->ctx != NULL)
+			io_loop_context_activate(timeout->ctx);
+		t_id = t_push_named("ioloop timeout handler %p",
+				    (void *)timeout->callback);
+		timeout->callback(timeout->context);
+		if (!t_pop(&t_id)) {
+			i_panic("Leaked a t_pop() call in timeout handler %p",
+				(void *)timeout->callback);
+		}
+		if (ioloop->cur_ctx != NULL)
+			io_loop_context_deactivate(ioloop->cur_ctx);
+		i_assert(ioloop == current_ioloop);
+	}
+}
+
+void io_loop_handle_timeouts(struct ioloop *ioloop)
+{
+	T_BEGIN {
+		io_loop_handle_timeouts_real(ioloop);
+	} T_END;
+
+	/* Free the unused memory in data stack once per second. This way if
+	   the data stack has grown excessively large temporarily, it won't
+	   permanently waste memory. And if the data stack grows back to the
+	   same large size, re-allocating it once per second doesn't cause
+	   performance problems. */
+	if (data_stack_last_free_unused != ioloop_time) {
+		if (data_stack_last_free_unused != 0)
+			data_stack_free_unused();
+		data_stack_last_free_unused = ioloop_time;
+	}
+}
+
+void io_loop_call_io(struct io *io)
+{
+	struct ioloop *ioloop = io->ioloop;
+	data_stack_frame_t t_id;
+
+	if (io->pending) {
+		i_assert(ioloop->io_pending_count > 0);
+		ioloop->io_pending_count--;
+		io->pending = FALSE;
+	}
+
+	if (io->ctx != NULL)
+		io_loop_context_activate(io->ctx);
+	t_id = t_push_named("ioloop handler %p",
+			    (void *)io->callback);
+	io->callback(io->context);
+	if (!t_pop(&t_id)) {
+		i_panic("Leaked a t_pop() call in I/O handler %p",
+			(void *)io->callback);
+	}
+	if (ioloop->cur_ctx != NULL)
+		io_loop_context_deactivate(ioloop->cur_ctx);
+	i_assert(ioloop == current_ioloop);
+}
+
+void io_loop_run(struct ioloop *ioloop)
+{
+	if (ioloop->handler_context == NULL)
+		io_loop_initialize_handler(ioloop);
+
+	if (ioloop->cur_ctx != NULL)
+		io_loop_context_deactivate(ioloop->cur_ctx);
+
+	/* recursive io_loop_run() isn't allowed for the same ioloop.
+	   it can break backends. */
+	i_assert(!ioloop->iolooping);
+	ioloop->iolooping = TRUE;
+
+	ioloop->running = TRUE;
+	while (ioloop->running)
+		io_loop_handler_run(ioloop);
+	ioloop->iolooping = FALSE;
+}
+
+static void io_loop_call_pending(struct ioloop *ioloop)
+{
+	struct io_file *io;
+
+	while (ioloop->io_pending_count > 0) {
+		io = ioloop->io_files;
+		do {
+			ioloop->next_io_file = io->next;
+			if (io->io.pending)
+				io_loop_call_io(&io->io);
+			if (ioloop->io_pending_count == 0)
+				break;
+			io = ioloop->next_io_file;
+		} while (io != NULL);
+	}
+}
+
+void io_loop_handler_run(struct ioloop *ioloop)
+{
+	i_assert(ioloop == current_ioloop);
+
+	io_loop_timeouts_start_new(ioloop);
+	ioloop->wait_started = ioloop_timeval;
+	io_loop_handler_run_internal(ioloop);
+	io_loop_call_pending(ioloop);
+	if (ioloop->stop_after_run_loop)
+		io_loop_stop(ioloop);
+
+	i_assert(ioloop == current_ioloop);
+}
+
+void io_loop_stop(struct ioloop *ioloop)
+{
+        ioloop->running = FALSE;
+	ioloop->stop_after_run_loop = FALSE;
+}
+
+void io_loop_stop_delayed(struct ioloop *ioloop)
+{
+        ioloop->stop_after_run_loop = TRUE;
+}
+
+void io_loop_set_running(struct ioloop *ioloop)
+{
+        ioloop->running = TRUE;
+}
+
+void io_loop_set_max_fd_count(struct ioloop *ioloop, unsigned int max_fds)
+{
+	ioloop->max_fd_count = max_fds;
+}
+
+bool io_loop_is_running(struct ioloop *ioloop)
+{
+        return ioloop->running;
+}
+
+void io_loop_time_refresh(void)
+{
+	i_gettimeofday(&ioloop_timeval);
+	ioloop_time = ioloop_timeval.tv_sec;
+}
+
+struct ioloop *io_loop_create(void)
+{
+	struct ioloop *ioloop;
+
+	if (!panic_on_leak_set) {
+		panic_on_leak_set = TRUE;
+		panic_on_leak = getenv("CORE_IO_LEAK") != NULL;
+	}
+
+	/* initialize time */
+	i_gettimeofday(&ioloop_timeval);
+	ioloop_time = ioloop_timeval.tv_sec;
+
+        ioloop = i_new(struct ioloop, 1);
+	ioloop->timeouts = priorityq_init(timeout_cmp, 32);
+	i_array_init(&ioloop->timeouts_new, 8);
+
+	ioloop->time_moved_callback = current_ioloop != NULL ?
+		current_ioloop->time_moved_callback :
+		io_loop_default_time_moved;
+
+	ioloop->prev = current_ioloop;
+        io_loop_set_current(ioloop);
+        return ioloop;
+}
+
+void io_loop_destroy(struct ioloop **_ioloop)
+{
+	struct ioloop *ioloop = *_ioloop;
+	struct timeout *to;
+	struct priorityq_item *item;
+	bool leaks = FALSE;
+
+	*_ioloop = NULL;
+
+	/* ->prev won't work unless loops are destroyed in create order */
+        i_assert(ioloop == current_ioloop);
+	if (array_is_created(&io_destroy_callbacks)) {
+		io_destroy_callback_t *callback;
+		array_foreach_elem(&io_destroy_callbacks, callback) T_BEGIN {
+			callback(current_ioloop);
+		} T_END;
+	}
+
+	io_loop_set_current(current_ioloop->prev);
+
+	if (ioloop->notify_handler_context != NULL)
+		io_loop_notify_handler_deinit(ioloop);
+
+	while (ioloop->io_files != NULL) {
+		struct io_file *io = ioloop->io_files;
+		struct io *_io = &io->io;
+		const char *error = t_strdup_printf(
+			"I/O leak: %p (%s:%u, fd %d)",
+			(void *)io->io.callback,
+			io->io.source_filename,
+			io->io.source_linenum, io->fd);
+
+		if (panic_on_leak)
+			i_panic("%s", error);
+		else
+			i_warning("%s", error);
+		io_remove(&_io);
+		leaks = TRUE;
+	}
+	i_assert(ioloop->io_pending_count == 0);
+
+	array_foreach_elem(&ioloop->timeouts_new, to) {
+		const char *error = t_strdup_printf(
+			"Timeout leak: %p (%s:%u)", (void *)to->callback,
+			to->source_filename,
+			to->source_linenum);
+
+		if (panic_on_leak)
+			i_panic("%s", error);
+		else
+			i_warning("%s", error);
+		timeout_free(to);
+		leaks = TRUE;
+	}
+	array_free(&ioloop->timeouts_new);
+
+	while ((item = priorityq_pop(ioloop->timeouts)) != NULL) {
+		struct timeout *to = (struct timeout *)item;
+		const char *error = t_strdup_printf(
+			"Timeout leak: %p (%s:%u)", (void *)to->callback,
+			to->source_filename,
+			to->source_linenum);
+
+		if (panic_on_leak)
+			i_panic("%s", error);
+		else
+			i_warning("%s", error);
+		timeout_free(to);
+		leaks = TRUE;
+	}
+	priorityq_deinit(&ioloop->timeouts);
+
+	while (ioloop->wait_timers != NULL) {
+		struct io_wait_timer *timer = ioloop->wait_timers;
+		const char *error = t_strdup_printf(
+			"IO wait timer leak: %s:%u",
+			timer->source_filename,
+			timer->source_linenum);
+
+		if (panic_on_leak)
+			i_panic("%s", error);
+		else
+			i_warning("%s", error);
+		io_wait_timer_remove(&timer);
+		leaks = TRUE;
+	}
+
+	if (leaks) {
+		const char *backtrace;
+		if (backtrace_get(&backtrace) == 0)
+			i_warning("Raw backtrace for leaks: %s", backtrace);
+	}
+
+	if (ioloop->handler_context != NULL)
+		io_loop_handler_deinit(ioloop);
+	if (ioloop->cur_ctx != NULL)
+		io_loop_context_unref(&ioloop->cur_ctx);
+	i_free(ioloop);
+}
+
+void io_loop_set_time_moved_callback(struct ioloop *ioloop,
+				     io_loop_time_moved_callback_t *callback)
+{
+	ioloop->time_moved_callback = callback;
+}
+
+static void io_switch_callbacks_free(void)
+{
+	array_free(&io_switch_callbacks);
+}
+
+static void io_destroy_callbacks_free(void)
+{
+	array_free(&io_destroy_callbacks);
+}
+
+void io_loop_set_current(struct ioloop *ioloop)
+{
+	io_switch_callback_t *callback;
+	struct ioloop *prev_ioloop = current_ioloop;
+
+	if (ioloop == current_ioloop)
+		return;
+
+	current_ioloop = ioloop;
+	if (array_is_created(&io_switch_callbacks)) {
+		array_foreach_elem(&io_switch_callbacks, callback) T_BEGIN {
+			callback(prev_ioloop);
+		} T_END;
+	}
+}
+
+struct ioloop *io_loop_get_root(void)
+{
+	struct ioloop *ioloop = current_ioloop;
+
+	while (ioloop->prev != NULL)
+		ioloop = ioloop->prev;
+	return ioloop;
+}
+
+void io_loop_add_switch_callback(io_switch_callback_t *callback)
+{
+	if (!array_is_created(&io_switch_callbacks)) {
+		i_array_init(&io_switch_callbacks, 4);
+		lib_atexit_priority(io_switch_callbacks_free, LIB_ATEXIT_PRIORITY_LOW);
+	}
+	array_push_back(&io_switch_callbacks, &callback);
+}
+
+void io_loop_remove_switch_callback(io_switch_callback_t *callback)
+{
+	io_switch_callback_t *const *callbackp;
+	unsigned int idx;
+
+	array_foreach(&io_switch_callbacks, callbackp) {
+		if (*callbackp == callback) {
+			idx = array_foreach_idx(&io_switch_callbacks, callbackp);
+			array_delete(&io_switch_callbacks, idx, 1);
+			return;
+		}
+	}
+	i_unreached();
+}
+
+void io_loop_add_destroy_callback(io_destroy_callback_t *callback)
+{
+	if (!array_is_created(&io_destroy_callbacks)) {
+		i_array_init(&io_destroy_callbacks, 4);
+		lib_atexit_priority(io_destroy_callbacks_free, LIB_ATEXIT_PRIORITY_LOW);
+	}
+	array_push_back(&io_destroy_callbacks, &callback);
+}
+
+void io_loop_remove_destroy_callback(io_destroy_callback_t *callback)
+{
+	io_destroy_callback_t *const *callbackp;
+	unsigned int idx;
+
+	array_foreach(&io_destroy_callbacks, callbackp) {
+		if (*callbackp == callback) {
+			idx = array_foreach_idx(&io_destroy_callbacks, callbackp);
+			array_delete(&io_destroy_callbacks, idx, 1);
+			return;
+		}
+	}
+	i_unreached();
+}
+
+struct ioloop_context *io_loop_context_new(struct ioloop *ioloop)
+{
+	struct ioloop_context *ctx;
+
+	ctx = i_new(struct ioloop_context, 1);
+	ctx->refcount = 1;
+	ctx->ioloop = ioloop;
+	i_array_init(&ctx->callbacks, 4);
+	return ctx;
+}
+
+void io_loop_context_ref(struct ioloop_context *ctx)
+{
+	i_assert(ctx->refcount > 0);
+
+	ctx->refcount++;
+}
+
+void io_loop_context_unref(struct ioloop_context **_ctx)
+{
+	struct ioloop_context *ctx = *_ctx;
+
+	*_ctx = NULL;
+
+	i_assert(ctx->refcount > 0);
+	if (--ctx->refcount > 0)
+		return;
+
+	/* cur_ctx itself keeps a reference */
+	i_assert(ctx->ioloop->cur_ctx != ctx);
+
+	array_free(&ctx->callbacks);
+	array_free(&ctx->global_event_stack);
+	i_free(ctx);
+}
+
+#undef io_loop_context_add_callbacks
+void io_loop_context_add_callbacks(struct ioloop_context *ctx,
+				   io_callback_t *activate,
+				   io_callback_t *deactivate, void *context)
+{
+	struct ioloop_context_callback cb;
+
+	i_zero(&cb);
+	cb.activate = activate;
+	cb.deactivate = deactivate;
+	cb.context = context;
+
+	array_push_back(&ctx->callbacks, &cb);
+}
+
+#undef io_loop_context_remove_callbacks
+void io_loop_context_remove_callbacks(struct ioloop_context *ctx,
+				      io_callback_t *activate,
+				      io_callback_t *deactivate, void *context)
+{
+	struct ioloop_context_callback *cb;
+
+	array_foreach_modifiable(&ctx->callbacks, cb) {
+		if (cb->context == context &&
+		    cb->activate == activate && cb->deactivate == deactivate) {
+			/* simply mark it as deleted, since we could get
+			   here from activate/deactivate loop */
+			cb->activate = NULL;
+			cb->deactivate = NULL;
+			cb->context = NULL;
+			return;
+		}
+	}
+	i_panic("io_loop_context_remove_callbacks() context not found");
+}
+
+static void
+io_loop_context_remove_deleted_callbacks(struct ioloop_context *ctx)
+{
+	const struct ioloop_context_callback *cbs;
+	unsigned int i, count;
+
+	cbs = array_get(&ctx->callbacks, &count);
+	for (i = 0; i < count; ) {
+		if (cbs[i].activate != NULL)
+			i++;
+		else {
+			array_delete(&ctx->callbacks, i, 1);
+			cbs = array_get(&ctx->callbacks, &count);
+		}
+	}
+}
+
+static void io_loop_context_push_global_events(struct ioloop_context *ctx)
+{
+	struct event *const *events;
+	unsigned int i, count;
+
+	ctx->root_global_event = event_get_global();
+
+	if (!array_is_created(&ctx->global_event_stack))
+		return;
+
+	/* push the global events from stack in reverse order */
+	events = array_get(&ctx->global_event_stack, &count);
+	if (count == 0)
+		return;
+
+	/* Remember the oldest global event. We're going to pop until that
+	   event when deactivating the context. */
+	for (i = count; i > 0; i--)
+		event_push_global(events[i-1]);
+	array_clear(&ctx->global_event_stack);
+}
+
+static void io_loop_context_pop_global_events(struct ioloop_context *ctx)
+{
+	struct event *event;
+
+	/* ioloop context is always global, so we can't push one ioloop context
+	   on top of another one. We'll need to rewind the global event stack
+	   until we've reached the event that started this context. We'll push
+	   these global events back when the ioloop context is activated
+	   again. (We'll assert-crash if the root event is freed before these
+	   global events have been popped.) */
+	while ((event = event_get_global()) != ctx->root_global_event) {
+		i_assert(event != NULL);
+		if (!array_is_created(&ctx->global_event_stack))
+			i_array_init(&ctx->global_event_stack, 4);
+		array_push_back(&ctx->global_event_stack, &event);
+		event_pop_global(event);
+	}
+	ctx->root_global_event = NULL;
+}
+
+void io_loop_context_activate(struct ioloop_context *ctx)
+{
+	struct ioloop_context_callback *cb;
+
+	i_assert(ctx->ioloop->cur_ctx == NULL);
+
+	ctx->ioloop->cur_ctx = ctx;
+	io_loop_context_push_global_events(ctx);
+	io_loop_context_ref(ctx);
+	array_foreach_modifiable(&ctx->callbacks, cb) {
+		i_assert(!cb->activated);
+		if (cb->activate != NULL) T_BEGIN {
+			cb->activate(cb->context);
+		} T_END;
+		cb->activated = TRUE;
+	}
+}
+
+void io_loop_context_deactivate(struct ioloop_context *ctx)
+{
+	struct ioloop_context_callback *cb;
+
+	i_assert(ctx->ioloop->cur_ctx == ctx);
+
+	array_foreach_modifiable(&ctx->callbacks, cb) {
+		if (!cb->activated) {
+			/* we just added this callback. don't deactivate it
+			   before it gets first activated. */
+		} else {
+			if (cb->deactivate != NULL) T_BEGIN {
+				cb->deactivate(cb->context);
+			} T_END;
+			cb->activated = FALSE;
+		}
+	}
+	ctx->ioloop->cur_ctx = NULL;
+	io_loop_context_pop_global_events(ctx);
+	io_loop_context_remove_deleted_callbacks(ctx);
+	io_loop_context_unref(&ctx);
+}
+
+void io_loop_context_switch(struct ioloop_context *ctx)
+{
+	if (ctx->ioloop->cur_ctx != NULL) {
+		if (ctx->ioloop->cur_ctx == ctx)
+			return;
+		io_loop_context_deactivate(ctx->ioloop->cur_ctx);
+		/* deactivation may remove the cur_ctx */
+		if (ctx->ioloop->cur_ctx != NULL)
+			io_loop_context_unref(&ctx->ioloop->cur_ctx);
+	}
+	io_loop_context_activate(ctx);
+}
+
+struct ioloop_context *io_loop_get_current_context(struct ioloop *ioloop)
+{
+	return ioloop->cur_ctx;
+}
+
+struct io *io_loop_move_io_to(struct ioloop *ioloop, struct io **_io)
+{
+	struct io *old_io = *_io;
+	struct io_file *old_io_file, *new_io_file;
+
+	if (old_io == NULL)
+		return NULL;
+
+	i_assert((old_io->condition & IO_NOTIFY) == 0);
+
+	if (old_io->ioloop == ioloop)
+		return old_io;
+
+	old_io_file = (struct io_file *)old_io;
+	new_io_file = io_add_file(ioloop, old_io_file->fd,
+				  old_io->condition, old_io->source_filename,
+				  old_io->source_linenum,
+				  old_io->callback, old_io->context);
+	if (old_io_file->istream != NULL) {
+		/* reference before io_remove() */
+		new_io_file->istream = old_io_file->istream;
+		i_stream_ref(new_io_file->istream);
+	}
+	if (old_io->pending)
+		io_set_pending(&new_io_file->io);
+	io_remove(_io);
+	if (new_io_file->istream != NULL) {
+		/* update istream io after it was removed with io_remove() */
+		i_stream_set_io(new_io_file->istream, &new_io_file->io);
+	}
+	return &new_io_file->io;
+}
+
+struct io *io_loop_move_io(struct io **_io)
+{
+	return io_loop_move_io_to(current_ioloop, _io);
+}
+
+struct timeout *io_loop_move_timeout_to(struct ioloop *ioloop,
+					struct timeout **_timeout)
+{
+	struct timeout *new_to, *old_to = *_timeout;
+
+	if (old_to == NULL || old_to->ioloop == ioloop)
+		return old_to;
+
+	new_to = timeout_copy(old_to, ioloop);
+	timeout_remove(_timeout);
+	return new_to;
+}
+
+struct timeout *io_loop_move_timeout(struct timeout **_timeout)
+{
+	return io_loop_move_timeout_to(current_ioloop, _timeout);
+}
+
+bool io_loop_have_ios(struct ioloop *ioloop)
+{
+	return ioloop->io_files != NULL;
+}
+
+bool io_loop_have_immediate_timeouts(struct ioloop *ioloop)
+{
+	struct timeval tv;
+
+	return io_loop_get_wait_time(ioloop, &tv) == 0;
+}
+
+bool io_loop_is_empty(struct ioloop *ioloop)
+{
+	return ioloop->io_files == NULL &&
+		priorityq_count(ioloop->timeouts) == 0 &&
+		array_count(&ioloop->timeouts_new) == 0;
+}
+
+uint64_t io_loop_get_wait_usecs(struct ioloop *ioloop)
+{
+	return ioloop->ioloop_wait_usecs;
+}
+
+enum io_condition io_loop_find_fd_conditions(struct ioloop *ioloop, int fd)
+{
+	enum io_condition conditions = 0;
+	struct io_file *io;
+
+	i_assert(fd >= 0);
+
+	for (io = ioloop->io_files; io != NULL; io = io->next) {
+		if (io->fd == fd)
+			conditions |= io->io.condition;
+	}
+	return conditions;
+}
+
+#undef io_wait_timer_add_to
+struct io_wait_timer *
+io_wait_timer_add_to(struct ioloop *ioloop, const char *source_filename,
+		     unsigned int source_linenum)
+{
+	struct io_wait_timer *timer;
+
+	timer = i_new(struct io_wait_timer, 1);
+	timer->ioloop = ioloop;
+	timer->source_filename = source_filename;
+	timer->source_linenum = source_linenum;
+	DLLIST_PREPEND(&ioloop->wait_timers, timer);
+	return timer;
+}
+
+#undef io_wait_timer_add
+struct io_wait_timer *
+io_wait_timer_add(const char *source_filename, unsigned int source_linenum)
+{
+	return io_wait_timer_add_to(current_ioloop, source_filename,
+				    source_linenum);
+}
+
+struct io_wait_timer *io_wait_timer_move_to(struct io_wait_timer **_timer,
+					    struct ioloop *ioloop)
+{
+	struct io_wait_timer *timer = *_timer;
+
+	*_timer = NULL;
+	DLLIST_REMOVE(&timer->ioloop->wait_timers, timer);
+	DLLIST_PREPEND(&ioloop->wait_timers, timer);
+	timer->ioloop = ioloop;
+	return timer;
+}
+
+struct io_wait_timer *io_wait_timer_move(struct io_wait_timer **_timer)
+{
+	return io_wait_timer_move_to(_timer, current_ioloop);
+}
+
+void io_wait_timer_remove(struct io_wait_timer **_timer)
+{
+	struct io_wait_timer *timer = *_timer;
+
+	*_timer = NULL;
+	DLLIST_REMOVE(&timer->ioloop->wait_timers, timer);
+	i_free(timer);
+}
+
+uint64_t io_wait_timer_get_usecs(struct io_wait_timer *timer)
+{
+	return timer->usecs;
+}
+
+struct event *io_loop_get_active_global_root(void)
+{
+	if (current_ioloop == NULL)
+		return NULL;
+	if (current_ioloop->cur_ctx == NULL)
+		return NULL;
+	return current_ioloop->cur_ctx->root_global_event;
+}