1 files changed, 68 insertions, 0 deletions
diff --git a/lib/isc/unix/os.c b/lib/isc/unix/os.c
new file mode 100644
index 0000000..5577587
--- /dev/null
+++ b/lib/isc/unix/os.c
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <isc/os.h>
+
+#ifdef HAVE_SYSCONF
+
+#include <unistd.h>
+
+static long
+sysconf_ncpus(void) {
+#if defined(_SC_NPROCESSORS_ONLN)
+	return (sysconf((_SC_NPROCESSORS_ONLN)));
+#elif defined(_SC_NPROC_ONLN)
+	return (sysconf((_SC_NPROC_ONLN)));
+#else  /* if defined(_SC_NPROCESSORS_ONLN) */
+	return (0);
+#endif /* if defined(_SC_NPROCESSORS_ONLN) */
+}
+#endif /* HAVE_SYSCONF */
+
+#if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME)
+#include <sys/param.h> /* for NetBSD */
+#include <sys/sysctl.h>
+#include <sys/types.h> /* for FreeBSD */
+
+static int
+sysctl_ncpus(void) {
+	int ncpu, result;
+	size_t len;
+
+	len = sizeof(ncpu);
+	result = sysctlbyname("hw.ncpu", &ncpu, &len, 0, 0);
+	if (result != -1) {
+		return (ncpu);
+	}
+	return (0);
+}
+#endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */
+
+unsigned int
+isc_os_ncpus(void) {
+	long ncpus = 0;
+
+#if defined(HAVE_SYSCONF)
+	ncpus = sysconf_ncpus();
+#endif /* if defined(HAVE_SYSCONF) */
+#if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME)
+	if (ncpus <= 0) {
+		ncpus = sysctl_ncpus();
+	}
+#endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */
+	if (ncpus <= 0) {
+		ncpus = 1;
+	}
+
+	return ((unsigned int)ncpus);
+}