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

Sources/OpenVPN3/openvpn/common/scoped_fd.hpp

@@ -0,0 +1,140 @@
+//    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/>.
+
+// A scoped file descriptor that is automatically closed by its destructor.
+
+#ifndef OPENVPN_COMMON_SCOPED_FD_H
+#define OPENVPN_COMMON_SCOPED_FD_H
+
+#include <unistd.h> // for close()
+#include <errno.h>
+
+namespace openvpn {
+
+  class ScopedFD
+  {
+    ScopedFD(const ScopedFD&) = delete;
+    ScopedFD& operator=(const ScopedFD&) = delete;
+
+  public:
+    typedef int base_type;
+
+    ScopedFD() : fd(undefined()) {}
+
+    explicit ScopedFD(const int fd_arg)
+      : fd(fd_arg) {}
+
+    static int undefined() { return -1; }
+
+    int release()
+    {
+      const int ret = fd;
+      fd = -1;
+      //OPENVPN_LOG("**** SFD RELEASE=" << ret);
+      return ret;
+    }
+
+    static bool defined_static(int fd)
+    {
+      return fd >= 0;
+    }
+
+    bool defined() const
+    {
+      return defined_static(fd);
+    }
+
+    int operator()() const
+    {
+      return fd;
+    }
+
+    void reset(const int fd_arg)
+    {
+      close();
+      fd = fd_arg;
+      //OPENVPN_LOG("**** SFD RESET=" << fd);
+    }
+
+    void reset()
+    {
+      close();
+    }
+
+    // unusual semantics: replace fd without closing it first
+    void replace(const int fd_arg)
+    {
+      //OPENVPN_LOG("**** SFD REPLACE " << fd << " -> " << fd_arg);
+      fd = fd_arg;
+    }
+
+    // return false if close error
+    bool close()
+    {
+      return close_with_errno() == 0;
+    }
+
+    // return errno value if close error, otherwise return 0
+    int close_with_errno()
+    {
+      int eno = 0;
+      if (defined())
+	{
+	  if (::close(fd) == -1)
+	    eno = errno;
+	  post_close(eno);
+	  //OPENVPN_LOG("**** SFD CLOSE fd=" << fd << " errno=" << eno);
+	  fd = -1;
+	}
+      return eno;
+    }
+
+    virtual void post_close(const int close_errno)
+    {
+    }
+
+    virtual ~ScopedFD()
+    {
+      //OPENVPN_LOG("**** SFD DESTRUCTOR");
+      close();
+    }
+
+    ScopedFD(ScopedFD&& other) noexcept
+    {
+      fd = other.fd;
+      other.fd = -1;
+    }
+
+    ScopedFD& operator=(ScopedFD&& other) noexcept
+    {
+      close();
+      fd = other.fd;
+      other.fd = -1;
+      return *this;
+    }
+
+  private:
+    int fd;
+  };
+
+} // namespace openvpn
+
+#endif // OPENVPN_COMMON_SCOPED_FD_H