From 6df5acf970852a94b254800dc69569bd1f4c9ae8 Mon Sep 17 00:00:00 2001
From: Karel Zak
Date: Wed, 24 Oct 2018 12:28:13 +0200
Subject: lib/timer: add fallback if timer_create() not available

* add struct ul_timer as API abstraction to hide differences between
timer_create() and setitimer()

* add setitimer() detection to ./configure.ac

* add fallback code to use setitimer() if timer_create() not available
  (for example on OSX)

Addresses: https://github.com/karelzak/util-linux/issues/584
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 lib/timer.c | 40 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 5 deletions(-)

(limited to 'lib')

diff --git a/lib/timer.c b/lib/timer.c
index 210c726cb..c1ea54eb8 100644
--- a/lib/timer.c
+++ b/lib/timer.c
@@ -27,7 +27,9 @@
  * The applications need to ensure that they can tolerate multiple signal
  * deliveries.
  */
-int setup_timer(timer_t * t_id, struct itimerval *timeout,
+#ifdef HAVE_TIMER_CREATE
+int setup_timer(struct ul_timer *timer,
+		struct itimerval *timeout,
 		void (*timeout_handler)(int, siginfo_t *, void *))
 {
 	time_t sec = timeout->it_value.tv_sec;
@@ -52,14 +54,42 @@ int setup_timer(timer_t * t_id, struct itimerval *timeout,
 
 	if (sigaction(SIGALRM, &sig_a, NULL))
 		return 1;
-	if (timer_create(CLOCK_MONOTONIC, &sig_e, t_id))
+	if (timer_create(CLOCK_MONOTONIC, &sig_e, &timer->t_id))
 		return 1;
-	if (timer_settime(*t_id, 0, &val, NULL))
+	if (timer_settime(timer->t_id, 0, &val, NULL))
 		return 1;
 	return 0;
 }
+void cancel_timer(struct ul_timer *timer)
+{
+	timer_delete(timer->t_id);
+}
+
+#else /* !HAVE_TIMER_CREATE */
+
+int setup_timer(struct ul_timer *timer,
+		struct itimerval *timeout,
+		void (*timeout_handler)(int, siginfo_t *, void *))
+{
+	struct sigaction sa;
+
+	memset(&sa, 0, sizeof sa);
+	memset(timer, 0, sizeof(*timer));
 
-void cancel_timer(timer_t *t_id)
+	sa.sa_flags = SA_SIGINFO | SA_RESETHAND;
+	sa.sa_sigaction = timeout_handler;
+
+	if (sigaction(SIGALRM, &sa, &timer->old_sa))
+		return 1;
+	if (setitimer(ITIMER_REAL, timeout, &timer->old_timer) != 0)
+		return 1;
+	return 0;
+}
+
+void cancel_timer(struct ul_timer *timer)
 {
-	timer_delete(*t_id);
+	setitimer(ITIMER_REAL, &timer->old_timer, NULL);
+        sigaction(SIGALRM, &timer->old_sa, NULL);
+
 }
+#endif /* !HAVE_TIMER_CREATE */
-- 
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