From b045529c40c83601909dca7b76a53498e9a70f33 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 10 Apr 2024 21:05:44 +0200
Subject: Adding upstream version 3.3.4.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/contrib/semaphore.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 src/contrib/semaphore.c

(limited to 'src/contrib/semaphore.c')

diff --git a/src/contrib/semaphore.c b/src/contrib/semaphore.c
new file mode 100644
index 0000000..1953fc3
--- /dev/null
+++ b/src/contrib/semaphore.c
@@ -0,0 +1,134 @@
+/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "semaphore.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+
+#if defined(__APPLE__)
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+#endif
+
+#define SEM_STATUS_POSIX INT_MIN
+
+void knot_sem_init(knot_sem_t *sem, int value)
+{
+	assert((sem != NULL) && (value != SEM_STATUS_POSIX));
+	if (value < 0) {
+		goto nonposix;
+	}
+	int ret = sem_init(&sem->semaphore, 1, value);
+	if (ret == 0) {
+		sem->status = SEM_STATUS_POSIX;
+		return;
+	}
+nonposix:
+	knot_sem_init_nonposix(sem, value);
+}
+
+void knot_sem_init_nonposix(knot_sem_t *sem, int value)
+{
+	assert((sem != NULL) && (value != SEM_STATUS_POSIX));
+	sem->status = value;
+	sem->status_lock = malloc(sizeof(*sem->status_lock));
+	pthread_mutex_init(&sem->status_lock->mutex, NULL);
+	pthread_cond_init(&sem->status_lock->cond, NULL);
+}
+
+void knot_sem_reset(knot_sem_t *sem, int value)
+{
+	assert((sem != NULL) && (value != SEM_STATUS_POSIX) && (sem->status != SEM_STATUS_POSIX));
+	pthread_mutex_lock(&sem->status_lock->mutex);
+	sem->status = value;
+	pthread_cond_signal(&sem->status_lock->cond);
+	pthread_mutex_unlock(&sem->status_lock->mutex);
+}
+
+void knot_sem_wait(knot_sem_t *sem)
+{
+	assert(sem != NULL);
+	if (sem->status == SEM_STATUS_POSIX) {
+		int semret;
+		do {
+			semret = sem_wait(&sem->semaphore);
+		} while (semret != 0); // repeat wait as it might be interrupted by a signal
+	} else {
+		pthread_mutex_lock(&sem->status_lock->mutex);
+		while (sem->status <= 0) {
+			pthread_cond_wait(&sem->status_lock->cond, &sem->status_lock->mutex);
+		}
+		sem->status--;
+		pthread_mutex_unlock(&sem->status_lock->mutex);
+	}
+}
+
+void knot_sem_wait_post(knot_sem_t *sem)
+{
+	assert((sem != NULL) && (sem->status != SEM_STATUS_POSIX));
+	pthread_mutex_lock(&sem->status_lock->mutex);
+	while (sem->status <= 0) {
+		pthread_cond_wait(&sem->status_lock->cond, &sem->status_lock->mutex);
+	}
+	pthread_cond_signal(&sem->status_lock->cond);
+	pthread_mutex_unlock(&sem->status_lock->mutex);
+}
+
+void knot_sem_get_ahead(knot_sem_t *sem)
+{
+	assert((sem != NULL) && (sem->status != SEM_STATUS_POSIX));
+	pthread_mutex_lock(&sem->status_lock->mutex);
+	sem->status--;
+	pthread_mutex_unlock(&sem->status_lock->mutex);
+}
+
+void knot_sem_get_assert(knot_sem_t *sem)
+{
+	assert((sem != NULL) && (sem->status != SEM_STATUS_POSIX));
+	pthread_mutex_lock(&sem->status_lock->mutex);
+	assert(sem->status > 0);
+	sem->status--;
+	pthread_mutex_unlock(&sem->status_lock->mutex);
+}
+
+void knot_sem_post(knot_sem_t *sem)
+{
+	assert(sem != NULL);
+	if (sem->status == SEM_STATUS_POSIX) {
+		int semret = sem_post(&sem->semaphore);
+		(void)semret;
+		assert(semret == 0);
+	} else {
+		pthread_mutex_lock(&sem->status_lock->mutex);
+		sem->status++;
+		pthread_cond_signal(&sem->status_lock->cond);
+		pthread_mutex_unlock(&sem->status_lock->mutex);
+	}
+}
+
+void knot_sem_destroy(knot_sem_t *sem)
+{
+	assert(sem != NULL);
+	knot_sem_wait(sem); // NOTE this is questionable if the initial value was > 1
+	if (sem->status == SEM_STATUS_POSIX) {
+		sem_destroy(&sem->semaphore);
+	} else {
+		pthread_cond_destroy(&sem->status_lock->cond);
+		pthread_mutex_destroy(&sem->status_lock->mutex);
+		free(sem->status_lock);
+	}
+}
-- 
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