Merge tag 'upstream/2.3_rc1'

Upstream version 2.3_rc1

1 files changed, 1011 insertions, 0 deletions

diff --git a/src/openvpn/win32.c b/src/openvpn/win32.c
new file mode 100644
index 0000000..2db96a8
--- /dev/null
+++ b/src/openvpn/win32.c
@@ -0,0 +1,1011 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/*
+ * Win32-specific OpenVPN code, targetted at the mingw
+ * development environment.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#ifdef WIN32
+
+#include "buffer.h"
+#include "error.h"
+#include "mtu.h"
+#include "sig.h"
+#include "win32.h"
+#include "misc.h"
+
+#include "memdbg.h"
+
+/*
+ * Windows internal socket API state (opaque).
+ */
+static struct WSAData wsa_state; /* GLOBAL */
+
+/*
+ * Should we call win32_pause() on program exit?
+ */
+static bool pause_exit_enabled = false; /* GLOBAL */
+
+/*
+ * win32_signal is used to get input from the keyboard
+ * if we are running in a console, or get input from an
+ * event object if we are running as a service.
+ */
+
+struct win32_signal win32_signal; /* GLOBAL */
+
+/*
+ * Save our old window title so we can restore
+ * it on exit.
+ */
+struct window_title window_title; /* GLOBAL*/
+
+/*
+ * Special global semaphore used to protect network
+ * shell commands from simultaneous instantiation.
+ */
+
+struct semaphore netcmd_semaphore; /* GLOBAL */
+
+/*
+ * Windows system pathname such as c:\windows
+ */
+static char *win_sys_path = NULL; /* GLOBAL */
+
+void
+init_win32 (void)
+{
+  if (WSAStartup(0x0101, &wsa_state))
+    {
+      msg (M_ERR, "WSAStartup failed");
+    }
+  window_title_clear (&window_title);
+  win32_signal_clear (&win32_signal);
+  netcmd_semaphore_init ();
+}
+
+void
+uninit_win32 (void)
+{
+  netcmd_semaphore_close ();
+  if (pause_exit_enabled)
+    {
+      if (win32_signal.mode == WSO_MODE_UNDEF)
+	{
+	  struct win32_signal w;
+	  win32_signal_open (&w, WSO_FORCE_CONSOLE, NULL, false);
+	  win32_pause (&w);
+	  win32_signal_close (&w);
+	}
+      else
+	win32_pause (&win32_signal);
+    }
+  window_title_restore (&window_title);
+  win32_signal_close (&win32_signal);
+  WSACleanup ();
+  free (win_sys_path);
+}
+
+void
+set_pause_exit_win32 (void)
+{
+  pause_exit_enabled = true;
+}
+
+bool
+init_security_attributes_allow_all (struct security_attributes *obj)
+{
+  CLEAR (*obj);
+
+  obj->sa.nLength = sizeof (SECURITY_ATTRIBUTES);
+  obj->sa.lpSecurityDescriptor = &obj->sd;
+  obj->sa.bInheritHandle = FALSE;
+  if (!InitializeSecurityDescriptor (&obj->sd, SECURITY_DESCRIPTOR_REVISION))
+    return false;
+  if (!SetSecurityDescriptorDacl (&obj->sd, TRUE, NULL, FALSE))
+    return false;
+  return true;
+}
+
+void
+overlapped_io_init (struct overlapped_io *o,
+		    const struct frame *frame,
+		    BOOL event_state,
+		    bool tuntap_buffer) /* if true: tuntap buffer, if false: socket buffer */
+{
+  CLEAR (*o);
+
+  /* manual reset event, initially set according to event_state */
+  o->overlapped.hEvent = CreateEvent (NULL, TRUE, event_state, NULL);
+  if (o->overlapped.hEvent == NULL)
+    msg (M_ERR, "Error: overlapped_io_init: CreateEvent failed");
+
+  /* allocate buffer for overlapped I/O */
+  alloc_buf_sock_tun (&o->buf_init, frame, tuntap_buffer, 0);
+}
+
+void
+overlapped_io_close (struct overlapped_io *o)
+{
+  if (o->overlapped.hEvent)
+    {
+      if (!CloseHandle (o->overlapped.hEvent))
+	msg (M_WARN | M_ERRNO, "Warning: CloseHandle failed on overlapped I/O event object");
+    }
+  free_buf (&o->buf_init);
+}
+
+char *
+overlapped_io_state_ascii (const struct overlapped_io *o)
+{
+  switch (o->iostate)
+    {
+    case IOSTATE_INITIAL:
+      return "0";
+    case IOSTATE_QUEUED:
+      return "Q";
+    case IOSTATE_IMMEDIATE_RETURN:
+      return "1";
+    }
+  return "?";
+}
+
+/*
+ * Event-based notification of network events
+ */
+
+void
+init_net_event_win32 (struct rw_handle *event, long network_events, socket_descriptor_t sd, unsigned int flags)
+{
+  /* manual reset events, initially set to unsignaled */
+
+  /* initialize write event */
+  if (!(flags & NE32_PERSIST_EVENT) || !event->write)
+    {
+      if (flags & NE32_WRITE_EVENT)
+	{
+	  event->write = CreateEvent (NULL, TRUE, FALSE, NULL);
+	  if (event->write == NULL)
+	    msg (M_ERR, "Error: init_net_event_win32: CreateEvent (write) failed");
+	}
+      else
+	event->write = NULL;
+    }
+
+  /* initialize read event */
+  if (!(flags & NE32_PERSIST_EVENT) || !event->read)
+    {
+      event->read = CreateEvent (NULL, TRUE, FALSE, NULL);
+      if (event->read == NULL)
+	msg (M_ERR, "Error: init_net_event_win32: CreateEvent (read) failed");
+    }
+  
+  /* setup network events to change read event state */
+  if (WSAEventSelect (sd, event->read, network_events) != 0)
+    msg (M_FATAL | M_ERRNO, "Error: init_net_event_win32: WSAEventSelect call failed");
+}
+
+long
+reset_net_event_win32 (struct rw_handle *event, socket_descriptor_t sd)
+{
+  WSANETWORKEVENTS wne;  
+  if (WSAEnumNetworkEvents (sd, event->read, &wne) != 0)
+    {
+      msg (M_FATAL | M_ERRNO, "Error: reset_net_event_win32: WSAEnumNetworkEvents call failed");
+      return 0; /* NOTREACHED */
+    }
+  else
+    return wne.lNetworkEvents;
+}
+
+void
+close_net_event_win32 (struct rw_handle *event, socket_descriptor_t sd, unsigned int flags)
+{
+  if (event->read)
+    {
+      if (socket_defined (sd))
+	{
+	  if (WSAEventSelect (sd, event->read, 0) != 0)
+	    msg (M_WARN | M_ERRNO, "Warning: close_net_event_win32: WSAEventSelect call failed");
+	}
+      if (!ResetEvent (event->read))
+	msg (M_WARN | M_ERRNO, "Warning: ResetEvent (read) failed in close_net_event_win32");
+      if (!(flags & NE32_PERSIST_EVENT))
+	{
+	  if (!CloseHandle (event->read))
+	    msg (M_WARN | M_ERRNO, "Warning: CloseHandle (read) failed in close_net_event_win32");
+	  event->read = NULL;
+	}
+    }
+
+  if (event->write)
+    {
+      if (!ResetEvent (event->write))
+	msg (M_WARN | M_ERRNO, "Warning: ResetEvent (write) failed in close_net_event_win32");
+      if (!(flags & NE32_PERSIST_EVENT))
+	{
+	  if (!CloseHandle (event->write))
+	    msg (M_WARN | M_ERRNO, "Warning: CloseHandle (write) failed in close_net_event_win32");
+	  event->write = NULL;
+	}
+    }
+}
+
+/*
+ * struct net_event_win32
+ */
+
+void
+net_event_win32_init (struct net_event_win32 *ne)
+{
+  CLEAR (*ne);
+  ne->sd = SOCKET_UNDEFINED;
+}
+
+void
+net_event_win32_start (struct net_event_win32 *ne, long network_events, socket_descriptor_t sd)
+{
+  ASSERT (!socket_defined (ne->sd));
+  ne->sd = sd;
+  ne->event_mask = 0;
+  init_net_event_win32 (&ne->handle, network_events, sd, NE32_PERSIST_EVENT|NE32_WRITE_EVENT);
+}
+
+void
+net_event_win32_reset_write (struct net_event_win32 *ne)
+{
+  BOOL status;
+  if (ne->event_mask & FD_WRITE)
+    status = SetEvent (ne->handle.write);
+  else
+    status = ResetEvent (ne->handle.write);
+  if (!status)
+    msg (M_WARN | M_ERRNO, "Warning: SetEvent/ResetEvent failed in net_event_win32_reset_write");
+}
+
+void
+net_event_win32_reset (struct net_event_win32 *ne)
+{
+  ne->event_mask |= reset_net_event_win32 (&ne->handle, ne->sd);
+}
+
+void
+net_event_win32_stop (struct net_event_win32 *ne)
+{
+  if (net_event_win32_defined (ne))
+    close_net_event_win32 (&ne->handle, ne->sd, NE32_PERSIST_EVENT);
+  ne->sd = SOCKET_UNDEFINED;
+  ne->event_mask = 0;
+}
+
+void
+net_event_win32_close (struct net_event_win32 *ne)
+{
+  if (net_event_win32_defined (ne))
+    close_net_event_win32 (&ne->handle, ne->sd, 0);
+  net_event_win32_init (ne);
+}
+
+/*
+ * Simulate *nix signals on Windows.
+ *
+ * Two modes:
+ * (1) Console mode -- map keyboard function keys to signals
+ * (2) Service mode -- map Windows event object to SIGTERM
+ */
+
+void
+win32_signal_clear (struct win32_signal *ws)
+{
+  CLEAR (*ws);
+}
+
+void
+win32_signal_open (struct win32_signal *ws,
+		   int force,
+		   const char *exit_event_name,
+		   bool exit_event_initial_state)
+{
+  CLEAR (*ws);
+
+  ws->mode = WSO_MODE_UNDEF;
+  ws->in.read = INVALID_HANDLE_VALUE;
+  ws->in.write = INVALID_HANDLE_VALUE;
+  ws->console_mode_save = 0;
+  ws->console_mode_save_defined = false;
+
+  if (force == WSO_NOFORCE || force == WSO_FORCE_CONSOLE)
+    {
+      /*
+       * Try to open console.
+       */
+      ws->in.read = GetStdHandle (STD_INPUT_HANDLE);
+      if (ws->in.read != INVALID_HANDLE_VALUE)
+	{
+	  if (GetConsoleMode (ws->in.read, &ws->console_mode_save))
+	    {
+	      /* running on a console */
+	      const DWORD new_console_mode = ws->console_mode_save
+		& ~(ENABLE_WINDOW_INPUT
+		    | ENABLE_PROCESSED_INPUT
+		    | ENABLE_LINE_INPUT
+		    | ENABLE_ECHO_INPUT 
+		    | ENABLE_MOUSE_INPUT);
+
+	      if (new_console_mode != ws->console_mode_save)
+		{
+		  if (!SetConsoleMode (ws->in.read, new_console_mode))
+		    msg (M_ERR, "Error: win32_signal_open: SetConsoleMode failed");
+		  ws->console_mode_save_defined = true;
+		}
+	      ws->mode = WSO_MODE_CONSOLE;
+	    }
+	  else
+	    ws->in.read = INVALID_HANDLE_VALUE; /* probably running as a service */
+	}
+    }
+
+  /*
+   * If console open failed, assume we are running
+   * as a service.
+   */
+  if ((force == WSO_NOFORCE || force == WSO_FORCE_SERVICE)
+      && !HANDLE_DEFINED (ws->in.read) && exit_event_name)
+    {
+      struct security_attributes sa;
+
+      if (!init_security_attributes_allow_all (&sa))
+	msg (M_ERR, "Error: win32_signal_open: init SA failed");
+
+      ws->in.read = CreateEvent (&sa.sa,
+				 TRUE,
+				 exit_event_initial_state ? TRUE : FALSE,
+				 exit_event_name);
+      if (ws->in.read == NULL)
+	{
+	  msg (M_WARN|M_ERRNO, "NOTE: CreateEvent '%s' failed", exit_event_name);
+	}
+      else
+	{
+	  if (WaitForSingleObject (ws->in.read, 0) != WAIT_TIMEOUT)
+	    msg (M_FATAL, "ERROR: Exit Event ('%s') is signaled", exit_event_name);
+	  else
+	    ws->mode = WSO_MODE_SERVICE;
+	}
+    }
+}
+
+static bool
+keyboard_input_available (struct win32_signal *ws)
+{
+  ASSERT (ws->mode == WSO_MODE_CONSOLE);
+  if (HANDLE_DEFINED (ws->in.read))
+    {
+      DWORD n;
+      if (GetNumberOfConsoleInputEvents (ws->in.read, &n))
+	return n > 0;
+    }
+  return false;
+}
+
+static unsigned int
+keyboard_ir_to_key (INPUT_RECORD *ir)
+{
+  if (ir->Event.KeyEvent.uChar.AsciiChar == 0)
+    return ir->Event.KeyEvent.wVirtualScanCode;
+
+  if ((ir->Event.KeyEvent.dwControlKeyState
+       & (LEFT_ALT_PRESSED | RIGHT_ALT_PRESSED))
+      && (ir->Event.KeyEvent.wVirtualKeyCode != 18))
+    return ir->Event.KeyEvent.wVirtualScanCode * 256;
+
+  return ir->Event.KeyEvent.uChar.AsciiChar;
+}
+
+static unsigned int
+win32_keyboard_get (struct win32_signal *ws)
+{
+  ASSERT (ws->mode == WSO_MODE_CONSOLE);
+  if (HANDLE_DEFINED (ws->in.read))
+    {
+      INPUT_RECORD ir;
+      do {
+	DWORD n;
+	if (!keyboard_input_available (ws))
+	  return 0;
+	if (!ReadConsoleInput (ws->in.read, &ir, 1, &n))
+	  return 0;
+      } while (ir.EventType != KEY_EVENT || ir.Event.KeyEvent.bKeyDown != TRUE);
+
+      return keyboard_ir_to_key (&ir);
+    }
+  else
+    return 0;
+}
+
+void
+win32_signal_close (struct win32_signal *ws)
+{
+  if (ws->mode == WSO_MODE_SERVICE && HANDLE_DEFINED (ws->in.read))
+    CloseHandle (ws->in.read);
+  if (ws->console_mode_save_defined)
+    {
+      if (!SetConsoleMode (ws->in.read, ws->console_mode_save))
+	msg (M_ERR, "Error: win32_signal_close: SetConsoleMode failed");
+    }
+  CLEAR (*ws);
+}
+
+/*
+ * Return true if interrupt occurs in service mode.
+ */
+bool
+win32_service_interrupt (struct win32_signal *ws)
+{
+  if (ws->mode == WSO_MODE_SERVICE)
+    {
+      if (HANDLE_DEFINED (ws->in.read)
+	  && WaitForSingleObject (ws->in.read, 0) == WAIT_OBJECT_0)
+	return true;
+    }
+  return false;
+}
+
+int
+win32_signal_get (struct win32_signal *ws)
+{
+  int ret = 0;
+  if (siginfo_static.signal_received)
+    {
+      ret = siginfo_static.signal_received;
+    }
+  else
+    {
+      if (ws->mode == WSO_MODE_SERVICE)
+	{
+	  if (win32_service_interrupt (ws))
+	    ret = SIGTERM;
+	}
+      else if (ws->mode == WSO_MODE_CONSOLE)
+	{
+	  switch (win32_keyboard_get (ws))
+	    {
+	    case 0x3B: /* F1 -> USR1 */
+	      ret = SIGUSR1;
+	      break;
+	    case 0x3C: /* F2 -> USR2 */
+	      ret = SIGUSR2;
+	      break;
+	    case 0x3D: /* F3 -> HUP */
+	      ret = SIGHUP;
+	      break;
+	    case 0x3E: /* F4 -> TERM */
+	      ret = SIGTERM;
+	      break;
+	    }
+	}
+      if (ret)
+	{
+	  siginfo_static.signal_received = ret;
+	  siginfo_static.hard = true;
+	}
+    }
+  return ret;
+}
+
+void
+win32_pause (struct win32_signal *ws)
+{
+  if (ws->mode == WSO_MODE_CONSOLE && HANDLE_DEFINED (ws->in.read))
+    {
+      int status;
+      msg (M_INFO|M_NOPREFIX, "Press any key to continue...");
+      do {
+	status = WaitForSingleObject (ws->in.read, INFINITE);
+      } while (!win32_keyboard_get (ws));
+    }
+}
+
+/* window functions */
+
+void
+window_title_clear (struct window_title *wt)
+{
+  CLEAR (*wt);
+}
+
+void
+window_title_save (struct window_title *wt)
+{
+  if (!wt->saved)
+    {
+      if (!GetConsoleTitle (wt->old_window_title, sizeof (wt->old_window_title)))
+	{
+	  wt->old_window_title[0] = 0;
+	  wt->saved = false;
+	}
+      else
+	wt->saved = true;
+    }
+}
+
+void
+window_title_restore (const struct window_title *wt)
+{
+  if (wt->saved)
+    SetConsoleTitle (wt->old_window_title);
+}
+
+void
+window_title_generate (const char *title)
+{
+  struct gc_arena gc = gc_new ();
+  struct buffer out = alloc_buf_gc (256, &gc);
+  if (!title)
+    title = "";
+  buf_printf (&out, "[%s] " PACKAGE_NAME " " PACKAGE_VERSION " F4:EXIT F1:USR1 F2:USR2 F3:HUP", title);
+  SetConsoleTitle (BSTR (&out));
+  gc_free (&gc);
+}
+
+/* semaphore functions */
+
+void
+semaphore_clear (struct semaphore *s)
+{
+  CLEAR (*s);
+}
+
+void
+semaphore_open (struct semaphore *s, const char *name)
+{
+  struct security_attributes sa;
+
+  s->locked = false;
+  s->name = name;
+  s->hand = NULL;
+
+  if (init_security_attributes_allow_all (&sa))
+    s->hand = CreateSemaphore(&sa.sa, 1, 1, name);
+
+  if (s->hand == NULL)
+    msg (M_WARN|M_ERRNO, "WARNING: Cannot create Win32 semaphore '%s'", name);
+  else
+    dmsg (D_SEMAPHORE, "Created Win32 semaphore '%s'", s->name);
+}
+
+bool
+semaphore_lock (struct semaphore *s, int timeout_milliseconds)
+{
+  bool ret = true;
+
+  if (s->hand)
+    {
+      DWORD status;
+      ASSERT (!s->locked);
+
+      dmsg (D_SEMAPHORE_LOW, "Attempting to lock Win32 semaphore '%s' prior to net shell command (timeout = %d sec)",
+	   s->name,
+	   timeout_milliseconds / 1000);
+      status = WaitForSingleObject (s->hand, timeout_milliseconds);
+      if (status == WAIT_FAILED)
+	msg (M_ERR, "Wait failed on Win32 semaphore '%s'", s->name);
+      ret = (status == WAIT_TIMEOUT) ? false : true;
+      if (ret)
+	{
+	  dmsg (D_SEMAPHORE, "Locked Win32 semaphore '%s'", s->name);
+	  s->locked = true;
+	}
+      else
+	{
+	  dmsg (D_SEMAPHORE, "Wait on Win32 semaphore '%s' timed out after %d milliseconds",
+	       s->name,
+	       timeout_milliseconds);
+	}
+    }
+  return ret;
+}
+
+void
+semaphore_release (struct semaphore *s)
+{
+  if (s->hand)
+    {
+      ASSERT (s->locked);
+      dmsg (D_SEMAPHORE, "Releasing Win32 semaphore '%s'", s->name);
+      if (!ReleaseSemaphore(s->hand, 1, NULL))
+	msg (M_WARN | M_ERRNO, "ReleaseSemaphore failed on Win32 semaphore '%s'",
+	     s->name);
+      s->locked = false;
+    }
+}
+
+void
+semaphore_close (struct semaphore *s)
+{
+  if (s->hand)
+    {
+      if (s->locked)
+	semaphore_release (s);
+      dmsg (D_SEMAPHORE, "Closing Win32 semaphore '%s'", s->name);
+      CloseHandle (s->hand);
+      s->hand = NULL;
+    }
+}
+
+/*
+ * Special global semaphore used to protect network
+ * shell commands from simultaneous instantiation.
+ */
+
+void
+netcmd_semaphore_init (void)
+{
+  semaphore_open (&netcmd_semaphore, PACKAGE "_netcmd");
+}
+
+void
+netcmd_semaphore_close (void)
+{
+  semaphore_close (&netcmd_semaphore);
+}
+
+void
+netcmd_semaphore_lock (void)
+{
+  const int timeout_seconds = 600;
+  if (!semaphore_lock (&netcmd_semaphore, timeout_seconds * 1000))
+    msg (M_FATAL, "Cannot lock net command semaphore"); 
+}
+
+void
+netcmd_semaphore_release (void)
+{
+  semaphore_release (&netcmd_semaphore);
+}
+
+/*
+ * Return true if filename is safe to be used on Windows,
+ * by avoiding the following reserved names:
+ *
+ * CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9,
+ * LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9, and CLOCK$
+ *
+ * See: http://msdn.microsoft.com/en-us/library/aa365247.aspx
+ *  and http://msdn.microsoft.com/en-us/library/86k9f82k(VS.80).aspx
+ */
+
+static bool
+cmp_prefix (const char *str, const bool n, const char *pre)
+{
+  size_t i = 0;
+
+  if (!str)
+    return false;
+
+  while (true)
+    {
+      const int c1 = pre[i];
+      int c2 = str[i];
+      ++i;
+      if (c1 == '\0')
+	{
+	  if (n)
+	    {
+	      if (isdigit (c2))
+		c2 = str[i];
+	      else
+		return false;
+	    }
+	  return c2 == '\0' || c2 == '.';
+	}
+      else if (c2 == '\0')
+	return false;
+      if (c1 != tolower(c2))
+	return false;
+    }
+}
+
+bool
+win_safe_filename (const char *fn)
+{
+  if (cmp_prefix (fn, false, "con"))
+    return false;
+  if (cmp_prefix (fn, false, "prn"))
+    return false;
+  if (cmp_prefix (fn, false, "aux"))
+    return false;
+  if (cmp_prefix (fn, false, "nul"))
+    return false;
+  if (cmp_prefix (fn, true, "com"))
+    return false;
+  if (cmp_prefix (fn, true, "lpt"))
+    return false;
+  if (cmp_prefix (fn, false, "clock$"))
+    return false;
+  return true;
+}
+
+/*
+ * Service functions for openvpn_execve
+ */
+
+static char *
+env_block (const struct env_set *es)
+{
+  char * force_path = "PATH=C:\\Windows\\System32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem";
+
+  if (es)
+    {
+      struct env_item *e;
+      char *ret;
+      char *p;
+      size_t nchars = 1;
+      bool path_seen = false;
+      
+      for (e = es->list; e != NULL; e = e->next)
+	nchars += strlen (e->string) + 1;
+
+      nchars += strlen(force_path)+1;
+
+      ret = (char *) malloc (nchars);
+      check_malloc_return (ret);
+
+      p = ret;
+      for (e = es->list; e != NULL; e = e->next)
+	{
+	  if (env_allowed (e->string))
+	    {
+	      strcpy (p, e->string);
+	      p += strlen (e->string) + 1;
+	    }
+	  if ( strncmp(e->string, "PATH=", 5 ) == 0 )
+	    path_seen = true;
+	}
+
+      /* make sure PATH is set */
+      if ( !path_seen )
+	{
+	  msg( M_INFO, "env_block: add %s", force_path );
+	  strcpy( p, force_path );
+	  p += strlen(force_path) + 1;
+	}
+
+      *p = '\0';
+      return ret;
+    }
+  else
+    return NULL;
+}
+
+static WCHAR *
+wide_cmd_line (const struct argv *a, struct gc_arena *gc)
+{
+  size_t nchars = 1;
+  size_t maxlen = 0;
+  size_t i;
+  struct buffer buf;
+  char *work = NULL;
+
+  if (!a)
+    return NULL;
+
+  for (i = 0; i < a->argc; ++i)
+    {
+      const char *arg = a->argv[i];
+      const size_t len = strlen (arg);
+      nchars += len + 3;
+      if (len > maxlen)
+	maxlen = len;
+    }
+
+  work = gc_malloc (maxlen + 1, false, gc);
+  check_malloc_return (work);
+  buf = alloc_buf_gc (nchars, gc);
+
+  for (i = 0; i < a->argc; ++i)
+    {
+      const char *arg = a->argv[i];
+      strcpy (work, arg);
+      string_mod (work, CC_PRINT, CC_DOUBLE_QUOTE|CC_CRLF, '_');
+      if (i)
+	buf_printf (&buf, " ");
+      if (string_class (work, CC_ANY, CC_SPACE))
+	buf_printf (&buf, "%s", work);
+      else
+	buf_printf (&buf, "\"%s\"", work);
+    }
+
+  return wide_string (BSTR (&buf), gc);
+}
+
+/*
+ * Attempt to simulate fork/execve on Windows
+ */
+int
+openvpn_execve (const struct argv *a, const struct env_set *es, const unsigned int flags)
+{
+  int ret = -1;
+  static bool exec_warn = false;
+
+  if (a && a->argv[0])
+    {
+      if (openvpn_execve_allowed (flags))
+	{
+          struct gc_arena gc = gc_new ();
+          STARTUPINFOW start_info;
+          PROCESS_INFORMATION proc_info;
+
+          char *env = env_block (es);
+          WCHAR *cl = wide_cmd_line (a, &gc);
+          WCHAR *cmd = wide_string (a->argv[0], &gc);
+
+          CLEAR (start_info);
+          CLEAR (proc_info);
+
+          /* fill in STARTUPINFO struct */
+          GetStartupInfoW(&start_info);
+          start_info.cb = sizeof(start_info);
+          start_info.dwFlags = STARTF_USESHOWWINDOW;
+          start_info.wShowWindow = SW_HIDE;
+
+          if (CreateProcessW (cmd, cl, NULL, NULL, FALSE, 0, env, NULL, &start_info, &proc_info))
+            {
+              DWORD exit_status = 0;
+              CloseHandle (proc_info.hThread);
+              WaitForSingleObject (proc_info.hProcess, INFINITE);
+              if (GetExitCodeProcess (proc_info.hProcess, &exit_status))
+                ret = (int)exit_status;
+              else
+                msg (M_WARN|M_ERRNO, "openvpn_execve: GetExitCodeProcess %S failed", cmd);
+              CloseHandle (proc_info.hProcess);
+            }
+          else
+            {
+              msg (M_WARN|M_ERRNO, "openvpn_execve: CreateProcess %S failed", cmd);
+            }
+          free (env);
+          gc_free (&gc);
+        }
+      else if (!exec_warn && (script_security < SSEC_SCRIPTS))
+	{
+	  msg (M_WARN, SCRIPT_SECURITY_WARNING);
+          exec_warn = true;
+	}
+    }
+  else
+    {
+      msg (M_WARN, "openvpn_execve: called with empty argv");
+    }
+  return ret;
+}
+
+WCHAR *
+wide_string (const char* utf8, struct gc_arena *gc)
+{
+  int n = MultiByteToWideChar (CP_UTF8, 0, utf8, -1, NULL, 0);
+  WCHAR *ucs16 = gc_malloc (n * sizeof (WCHAR), false, gc);
+  MultiByteToWideChar (CP_UTF8, 0, utf8, -1, ucs16, n);
+  return ucs16;
+}
+
+/*
+ * call ourself in another process
+ */
+void
+fork_to_self (const char *cmdline)
+{
+  STARTUPINFO start_info;
+  PROCESS_INFORMATION proc_info;
+  char self_exe[256];
+  char *cl = string_alloc (cmdline, NULL);
+  DWORD status;
+
+  CLEAR (start_info);
+  CLEAR (proc_info);
+  CLEAR (self_exe);
+
+  status = GetModuleFileName (NULL, self_exe, sizeof(self_exe));
+  if (status == 0 || status == sizeof(self_exe))
+    {
+      msg (M_WARN|M_ERRNO, "fork_to_self: CreateProcess failed: cannot get module name via GetModuleFileName");
+      goto done;
+    }
+
+  /* fill in STARTUPINFO struct */
+  GetStartupInfo(&start_info);
+  start_info.cb = sizeof(start_info);
+  start_info.dwFlags = STARTF_USESHOWWINDOW;
+  start_info.wShowWindow = SW_HIDE;
+
+  if (CreateProcess (self_exe, cl, NULL, NULL, FALSE, 0, NULL, NULL, &start_info, &proc_info))
+    {
+      CloseHandle (proc_info.hThread);
+      CloseHandle (proc_info.hProcess);
+    }
+  else
+    {
+      msg (M_WARN|M_ERRNO, "fork_to_self: CreateProcess failed: %s", cmdline);
+    }
+
+ done:
+  free (cl);
+}
+
+char *
+get_win_sys_path (void)
+{
+  ASSERT (win_sys_path);
+  return win_sys_path;
+}
+
+void
+set_win_sys_path (const char *newpath, struct env_set *es)
+{
+  free (win_sys_path);
+  win_sys_path = string_alloc (newpath, NULL);
+  setenv_str (es, SYS_PATH_ENV_VAR_NAME, win_sys_path); /* route.exe needs this */
+}
+
+void
+set_win_sys_path_via_env (struct env_set *es)
+{
+  char buf[256];
+  DWORD status = GetEnvironmentVariable (SYS_PATH_ENV_VAR_NAME, buf, sizeof(buf));
+  if (!status)
+    msg (M_ERR, "Cannot find environmental variable %s", SYS_PATH_ENV_VAR_NAME);
+  if (status > sizeof (buf) - 1)
+    msg (M_FATAL, "String overflow attempting to read environmental variable %s", SYS_PATH_ENV_VAR_NAME);
+  set_win_sys_path (buf, es);
+}
+
+
+const char *
+win_get_tempdir()
+{
+  static char buf[MAX_PATH];
+  char *tmpdir = buf;
+
+  CLEAR(buf);
+
+  if (!GetTempPath(sizeof(buf),buf)) {
+    /* Warn if we can't find a valid temporary directory, which should
+     * be unlikely.
+     */
+    msg (M_WARN, "Could not find a suitable temporary directory."
+         " (GetTempPath() failed).  Consider to use --tmp-dir");
+    tmpdir = NULL;
+  }
+  return tmpdir;
+}
+#endif