Merge commit '86cc97e55fe346502462284d2e636a2b3708163e' as 'Sources/OpenVPN3'

Sources/OpenVPN3/openvpn/common/core.hpp

@@ -0,0 +1,70 @@
+//    OpenVPN -- An application to securely tunnel IP networks
+//               over a single port, with support for SSL/TLS-based
+//               session authentication and key exchange,
+//               packet encryption, packet authentication, and
+//               packet compression.
+//
+//    Copyright (C) 2012-2017 OpenVPN Inc.
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Affero General Public License Version 3
+//    as published by the Free Software Foundation.
+//
+//    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 Affero General Public License for more details.
+//
+//    You should have received a copy of the GNU Affero General Public License
+//    along with this program in the COPYING file.
+//    If not, see <http://www.gnu.org/licenses/>.
+
+// Linux methods for enumerating the number of cores on machine,
+// and binding a thread to a particular core.
+
+#ifndef OPENVPN_COMMON_CORE_H
+#define OPENVPN_COMMON_CORE_H
+
+#include <openvpn/common/platform.hpp>
+
+#if defined(OPENVPN_PLATFORM_TYPE_APPLE)
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#elif defined(OPENVPN_PLATFORM_LINUX)
+#include <unistd.h>
+#elif defined(OPENVPN_PLATFORM_WIN)
+#include <windows.h>
+#endif
+
+namespace openvpn {
+
+  inline int n_cores()
+  {
+    int count = std::thread::hardware_concurrency();
+    // C++11 allows thread::hardware_concurrency() to return 0, fall back
+    // to specific solution if we detect this
+    if (count > 0)
+      return count;
+
+#if defined(OPENVPN_PLATFORM_TYPE_APPLE)
+    size_t count_len = sizeof(count);
+    if (::sysctlbyname("hw.logicalcpu", &count, &count_len, NULL, 0) != 0)
+      count = 1;
+    return count;
+#elif defined(OPENVPN_PLATFORM_LINUX)
+    long ret = ::sysconf(_SC_NPROCESSORS_ONLN);
+    if (ret <= 0)
+      ret = 1;
+    return ret;
+#elif defined(OPENVPN_PLATFORM_WIN)
+    SYSTEM_INFO si;
+    ::GetSystemInfo(&si);
+    return si.dwNumberOfProcessors;
+#else
+#error no implementation for n_cores()
+#endif
+  }
+
+}
+
+#endif