* Makefile.in (DLL_OFILES): Add fhandler_mailslot.o.

* devices.h (FH_KMSG): Define new device.
	* devices.in: Add "/dev/kmsg" entry.
	* devices.cc: Regenerate.
	* dtable.cc (build_fh_pc): Handle case FH_KMSG.
	* fhandler.h (class fhandler_mailslot): New class.
	(class select_stuff): Add device_specific_mailslot pointer.
	* fhandler_mailslot.cc: New file.
	* select.cc (peek_mailslot): New function.
	(verify_mailslot): Ditto.
	(struct mailslotinf): New stuct to handle select on mailslots.
	(thread_mailslot): New function.
	(start_thread_mailslot): Ditto.
	(mailslot_cleanup): Ditto.
	(fhandler_mailslot::select_read): New method.
	* syslog.cc (klog_guard): New muto.
	(dev_kmsg): Local mailslot for kernel message device.
	(vklog): New function.
	(klog): Ditto.
	* winsup.h (vklog): Declare.
	(klog): Ditto.
	* include/sys/syslog.h: Define _PATH_KLOG.

winsup/cygwin/fhandler_mailslot.cc

@@ -0,0 +1,160 @@
+/* fhandler_mailslot.cc.  See fhandler.h for a description of the fhandler classes.
+
+   Copyright 2005 Red Hat, Inc.
+
+   This file is part of Cygwin.
+
+   This software is a copyrighted work licensed under the terms of the
+   Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+   details. */
+
+#include "winsup.h"
+#include <unistd.h>
+#include <sys/termios.h>
+
+#include <ntdef.h>
+#include "cygerrno.h"
+#include "perprocess.h"
+#include "security.h"
+#include "path.h"
+#include "fhandler.h"
+#include "dtable.h"
+#include "cygheap.h"
+#include "ntdll.h"
+
+/**********************************************************************/
+/* fhandler_mailslot */
+
+fhandler_mailslot::fhandler_mailslot ()
+  : fhandler_base ()
+{
+}
+
+int __stdcall
+fhandler_mailslot::fstat (struct __stat64 *buf)
+{
+  debug_printf ("here");
+
+  fhandler_base::fstat (buf);
+  if (is_auto_device ())
+    {
+      buf->st_mode = S_IFCHR | S_IRUSR | S_IWUSR;
+      buf->st_uid = geteuid32 ();
+      buf->st_gid = getegid32 ();
+      buf->st_nlink = 1;
+      buf->st_blksize = S_BLKSIZE;
+      time_as_timestruc_t (&buf->st_ctim);
+      buf->st_atim = buf->st_mtim = buf->st_ctim;
+    }
+  return 0;
+}
+
+int
+fhandler_mailslot::open (int flags, mode_t mode)
+{
+  int res = 0;
+  HANDLE x;
+
+  switch (flags & O_ACCMODE)
+    {
+    case O_RDONLY:	/* Server */
+      x = CreateMailslot (get_win32_name (),
+      			  0, /* Any message size */
+      			  (flags & O_NONBLOCK) ? 0 : MAILSLOT_WAIT_FOREVER,
+      			  &sec_none);
+      if (x == INVALID_HANDLE_VALUE)
+        {
+	  /* FIXME: It's not possible to open the read side of an existing
+	     mailslot using CreateFile.  You'll get a handle, but using it
+	     in ReadFile returns ERROR_INVALID_PARAMETER.  On the other
+	     hand, CreateMailslot returns with ERROR_ALREADY_EXISTS if the
+	     mailslot has been created already.
+	     So this is an exclusive open for now.  *Duplicating* read side
+	     handles works, though, so it might be an option to duplicate
+	     the handle from the first process to the current process for
+	     opening the mailslot. */
+#if 0
+	  if (GetLastError () != ERROR_ALREADY_EXISTS)
+	    {
+	      __seterrno ();
+	      break;
+	    }
+	  x = CreateFile (get_win32_name (), GENERIC_READ, wincap.shared (),
+			  &sec_none, OPEN_EXISTING, 0, 0);
+#endif
+	  if (x == INVALID_HANDLE_VALUE)
+	    {
+	      __seterrno ();
+	      break;
+	    }
+	}
+      set_io_handle (x);
+      set_flags (flags, O_BINARY);
+      res = 1;
+      set_open_status ();
+      break;
+    case O_WRONLY:	/* Client */
+      /* The client is the DLL exclusively.  Don't allow opening from
+         application code. */
+      extern fhandler_mailslot *dev_kmsg;
+      if (this != dev_kmsg)
+        {
+	  set_errno (EPERM);	/* As on Linux. */
+	  break;
+	}
+      x = CreateFile (get_win32_name (), GENERIC_WRITE, wincap.shared (),
+		      &sec_none, OPEN_EXISTING, 0, 0);
+      if (x == INVALID_HANDLE_VALUE)
+	{
+	  __seterrno ();
+	  break;
+	}
+      set_io_handle (x);
+      set_flags (flags, O_BINARY);
+      res = 1;
+      set_open_status ();
+      break;
+    default:
+      set_errno (EINVAL);
+      break;
+    }
+  return res;
+}
+
+int
+fhandler_mailslot::write (const void *ptr, size_t len)
+{
+  /* Check for 425/426 byte weirdness */
+  if (len == 425 || len == 426)
+    {
+      char buf[427];
+      buf[425] = buf[426] = '\0';
+      memcpy (buf, ptr, len);
+      return raw_write (buf, 427);
+    }
+  return raw_write (ptr, len);
+}
+
+int
+fhandler_mailslot::ioctl (unsigned int cmd, void *buf) 
+{
+  int res = -1;
+
+  switch (cmd)
+    {
+    case FIONBIO:
+      {
+	DWORD timeout = buf ? 0 : MAILSLOT_WAIT_FOREVER;
+	if (!SetMailslotInfo (get_handle (), timeout))
+	  {
+	    debug_printf ("SetMailslotInfo (%u): %E", timeout);
+	    break;
+	  }
+      }
+      /*FALLTHRU*/
+    default:
+      res =  fhandler_base::ioctl (cmd, buf);
+      break;
+    }
+  return res;
+}