From f6132c99e1781f8ca2df08ddd7271bf5895dff0d Mon Sep 17 00:00:00 2001
From: Tomas Mudrunka <tomas@mudrunka.cz>
Date: Fri, 2 Jul 2021 15:37:20 +0200
Subject: [PATCH] Pthread sleep

---
 c/pthread_extra/Makefile        |  2 +-
 c/pthread_extra/pthread_extra.h |  6 ++++
 c/pthread_extra/pthread_sleep.c | 49 +++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 c/pthread_extra/pthread_sleep.c

diff --git a/c/pthread_extra/Makefile b/c/pthread_extra/Makefile
index 1197cca..35fac9c 100644
--- a/c/pthread_extra/Makefile
+++ b/c/pthread_extra/Makefile
@@ -11,7 +11,7 @@ CXXFLAGS+=$(COPT) $(CERR) $(CDEF) -std=c++11 $(CLIB)
 LDFLAGS+=$(COPT) $(LIB)
 
 BIN=test
-OBJ=pthread_user_data.o pthread_pause.o pthread_multi.o pthread_msgqueue.o test.o
+OBJ=pthread_user_data.o pthread_sleep.o pthread_pause.o pthread_multi.o pthread_msgqueue.o test.o
 
 all: $(BIN)
 $(BIN): $(OBJ)
diff --git a/c/pthread_extra/pthread_extra.h b/c/pthread_extra/pthread_extra.h
index 4df45d9..56c440b 100644
--- a/c/pthread_extra/pthread_extra.h
+++ b/c/pthread_extra/pthread_extra.h
@@ -56,6 +56,12 @@ int pthread_unpause_all();
 int pthread_pause_reschedule(pthread_t thread);
 int pthread_extra_yield();
 
+// Pause compatible sleeps
+
+void pthread_nanosleep(struct timespec t);
+void pthread_nsleep(time_t s, long ns);
+void pthread_sleep(time_t s);
+
 // Message queues
 
 //Flags
diff --git a/c/pthread_extra/pthread_sleep.c b/c/pthread_extra/pthread_sleep.c
new file mode 100644
index 0000000..12712c1
--- /dev/null
+++ b/c/pthread_extra/pthread_sleep.c
@@ -0,0 +1,49 @@
+#include <pthread_extra.h>
+#include <time.h>
+#include <errno.h>
+
+#define NSEC_PER_SEC (1000*1000*1000)
+// timespec_normalise() from https://github.com/solemnwarning/timespec/
+struct timespec timespec_normalise(struct timespec ts)
+{
+	while(ts.tv_nsec >= NSEC_PER_SEC) {
+		++(ts.tv_sec); ts.tv_nsec -= NSEC_PER_SEC;
+	}
+	while(ts.tv_nsec <= -NSEC_PER_SEC) {
+		--(ts.tv_sec); ts.tv_nsec += NSEC_PER_SEC;
+	}
+	if(ts.tv_nsec < 0) { // Negative nanoseconds isn't valid according to POSIX.
+		--(ts.tv_sec); ts.tv_nsec = (NSEC_PER_SEC + ts.tv_nsec);
+	}
+	return ts;
+}
+
+void pthread_nanosleep(struct timespec t) {
+	//Sleep calls on Linux get interrupted by signals, causing premature wake
+	//Pthread (un)pause is built using signals
+	//Therefore we need self-restarting sleep implementation
+	//IO timeouts are restarted by SA_RESTART, but sleeps do need explicit restart
+	//We also need to sleep using absolute time, because relative time is paused
+	//You should use this in any thread that gets (un)paused
+
+	struct timespec wake;
+	clock_gettime(CLOCK_MONOTONIC, &wake);
+
+	t = timespec_normalise(t);
+	wake.tv_sec += t.tv_sec;
+	wake.tv_nsec += t.tv_nsec;
+	wake = timespec_normalise(wake);
+
+	while(clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &wake, NULL)) if(errno!=EINTR) break;
+	return;
+}
+void pthread_nsleep(time_t s, long ns) {
+	struct timespec t;
+	t.tv_sec = s;
+	t.tv_nsec = ns;
+	pthread_nanosleep(t);
+}
+
+void pthread_sleep(time_t s) {
+	pthread_nsleep(s, 0);
+}
-- 
2.30.2