hurd: Make mmap64 use vm_offset_t for overflow check

	The RPC interface used by mmap uses the unsigned vm_offset_t, not the
	signed off_t, so 32bit bigger than 2GiB values are fine actually.

	* sysdeps/mach/hurd/mmap64.c: New file.

1 files changed, 47 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/mmap64.c b/sysdeps/mach/hurd/mmap64.c
new file mode 100644
index 0000000000..24e1e3eb80
--- /dev/null
+++ b/sysdeps/mach/hurd/mmap64.c
@@ -0,0 +1,47 @@
+/* Copyright (C) 1997-2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+
+/* Map addresses starting near ADDR and extending for LEN bytes.  From
+   OFFSET into the file FD describes according to PROT and FLAGS.  If ADDR
+   is nonzero, it is the desired mapping address.  If the MAP_FIXED bit is
+   set in FLAGS, the mapping will be at ADDR exactly (which must be
+   page-aligned); otherwise the system chooses a convenient nearby address.
+   The return value is the actual mapping address chosen or MAP_FAILED
+   for errors (in which case `errno' is set).  A successful `mmap' call
+   deallocates any previous mapping for the affected region.  */
+
+__ptr_t
+__mmap64 (__ptr_t addr, size_t len, int prot, int flags, int fd,
+	  __off64_t offset)
+{
+  vm_offset_t small_offset = (vm_offset_t) offset;
+
+  if (small_offset != offset)
+    {
+      /* We cannot do this since the offset is too large.  */
+      __set_errno (EOVERFLOW);
+      return MAP_FAILED;
+    }
+
+  return __mmap (addr, len, prot, flags, fd, small_offset);
+}
+
+weak_alias (__mmap64, mmap64)