From 8870b2477e86a859fe0fab370681711671d0516e Mon Sep 17 00:00:00 2001
From: James Yonan <james@openvpn.net>
Date: Tue, 8 Sep 2015 22:21:26 -0700
Subject: [PATCH] Added linux-specific is_daemon_alive() function to determine
 if a particular daemon is running.

---
 openvpn/linux/daemon_alive.hpp | 47 ++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 openvpn/linux/daemon_alive.hpp

diff --git a/openvpn/linux/daemon_alive.hpp b/openvpn/linux/daemon_alive.hpp
new file mode 100644
index 00000000..ca1779cb
--- /dev/null
+++ b/openvpn/linux/daemon_alive.hpp
@@ -0,0 +1,47 @@
+//    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) 2012-2015 OpenVPN Technologies, 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/>.
+
+#ifndef OPENVPN_LINUX_DAEMON_ALIVE_H
+#define OPENVPN_LINUX_DAEMON_ALIVE_H
+
+#include <openvpn/common/file.hpp>
+#include <openvpn/common/string.hpp>
+
+namespace openvpn {
+  inline bool is_daemon_alive(const std::string& cmd,
+			      const std::string& pidfile)
+  {
+    try {
+      std::string pidstr = read_text(pidfile);
+      string::trim_crlf(pidstr);
+      const std::string cmdline_fn = "/proc/" + pidstr + "/cmdline";
+      BufferPtr cmdbuf = read_binary_linear(cmdline_fn);
+      const size_t len = ::strnlen((const char *)cmdbuf->c_data(), cmdbuf->size());
+      return cmd == std::string((const char *)cmdbuf->c_data(), len);
+    }
+    catch (const std::exception& e)
+      {
+	return false;
+      }
+  }
+}
+
+#endif