From 4abab5ad6c8465a7528ccdd5f49367da05f78bbd Mon Sep 17 00:00:00 2001
From: Vladimir Azarov <avm@intermediate-node.net>
Date: Tue, 1 Oct 2024 15:47:05 +0200
Subject: Initial version

---
 src/aio/aio_suspend.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 src/aio/aio_suspend.c

(limited to 'src/aio/aio_suspend.c')

diff --git a/src/aio/aio_suspend.c b/src/aio/aio_suspend.c
new file mode 100644
index 0000000..1f0c9aa
--- /dev/null
+++ b/src/aio/aio_suspend.c
@@ -0,0 +1,75 @@
+#include <aio.h>
+#include <errno.h>
+#include <time.h>
+#include "atomic.h"
+#include "pthread_impl.h"
+#include "aio_impl.h"
+
+int aio_suspend(const struct aiocb *const cbs[], int cnt, const struct timespec *ts)
+{
+	int i, tid = 0, ret, expect = 0;
+	struct timespec at;
+	volatile int dummy_fut = 0, *pfut;
+	int nzcnt = 0;
+	const struct aiocb *cb = 0;
+
+	pthread_testcancel();
+
+	if (cnt<0) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	for (i=0; i<cnt; i++) if (cbs[i]) {
+		if (aio_error(cbs[i]) != EINPROGRESS) return 0;
+		nzcnt++;
+		cb = cbs[i];
+	}
+
+	if (ts) {
+		clock_gettime(CLOCK_MONOTONIC, &at);
+		at.tv_sec += ts->tv_sec;
+		if ((at.tv_nsec += ts->tv_nsec) >= 1000000000) {
+			at.tv_nsec -= 1000000000;
+			at.tv_sec++;
+		}
+	}
+
+	for (;;) {
+		for (i=0; i<cnt; i++)
+			if (cbs[i] && aio_error(cbs[i]) != EINPROGRESS)
+				return 0;
+
+		switch (nzcnt) {
+		case 0:
+			pfut = &dummy_fut;
+			break;
+		case 1:
+			pfut = (void *)&cb->__err;
+			expect = EINPROGRESS | 0x80000000;
+			a_cas(pfut, EINPROGRESS, expect);
+			break;
+		default:
+			pfut = &__aio_fut;
+			if (!tid) tid = __pthread_self()->tid;
+			expect = a_cas(pfut, 0, tid);
+			if (!expect) expect = tid;
+			/* Need to recheck the predicate before waiting. */
+			for (i=0; i<cnt; i++)
+				if (cbs[i] && aio_error(cbs[i]) != EINPROGRESS)
+					return 0;
+			break;
+		}
+
+		ret = __timedwait_cp(pfut, expect, CLOCK_MONOTONIC, ts?&at:0, 1);
+
+		switch (ret) {
+		case ETIMEDOUT:
+			ret = EAGAIN;
+		case ECANCELED:
+		case EINTR:
+			errno = ret;
+			return -1;
+		}
+	}
+}
-- 
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