PR libstdc++/85632 fix wraparound in filesystem::space

On 32-bit targets any values over 4GB would wrap and produce the wrong
result.

	PR libstdc++/85632 use uintmax_t for arithmetic
	* src/filesystem/ops.cc (experimental::filesystem::space): Perform
	arithmetic in result type.
	* testsuite/experimental/filesystem/operations/space.cc: New.

From-SVN: r259911

3 files changed, 68 insertions, 3 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 79564c58897..c6ae45be633 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2018-05-03  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/85632 use uintmax_t for arithmetic
+	* src/filesystem/ops.cc (experimental::filesystem::space): Perform
+	arithmetic in result type.
+	* testsuite/experimental/filesystem/operations/space.cc: New.
+
 2018-03-02  Jonathan Wakely  <jwakely@redhat.com>
 
 	Backport from mainline
diff --git a/libstdc++-v3/src/filesystem/ops.cc b/libstdc++-v3/src/filesystem/ops.cc
index d4bd5207b63..056fa92a0e6 100644
--- a/libstdc++-v3/src/filesystem/ops.cc
+++ b/libstdc++-v3/src/filesystem/ops.cc
@@ -1391,10 +1391,11 @@ fs::space(const path& p, error_code& ec) noexcept
       ec.assign(errno, std::generic_category());
   else
     {
+      uintmax_t fragment_size = f.f_frsize;
       info = space_info{
-	f.f_blocks * f.f_frsize,
-	f.f_bfree * f.f_frsize,
-	f.f_bavail * f.f_frsize
+	f.f_blocks * fragment_size,
+	f.f_bfree * fragment_size,
+	f.f_bavail * fragment_size
       };
       ec.clear();
     }
diff --git a/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc b/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc
new file mode 100644
index 00000000000..aa6a6aeaa60
--- /dev/null
+++ b/libstdc++-v3/testsuite/experimental/filesystem/operations/space.cc
@@ -0,0 +1,57 @@
+// Copyright (C) 2017-2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This 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 General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-DUSE_FILESYSTEM_TS -lstdc++fs" }
+// { dg-do run { target c++11 } }
+// { dg-require-filesystem-ts "" }
+
+// 30.10.14.3 Permissions [fs.op.space]
+
+#include <experimental/filesystem>
+#include <testsuite_fs.h>
+#include <testsuite_hooks.h>
+
+namespace fs = std::experimental::filesystem;
+
+void
+test01()
+{
+  fs::space_info s = fs::space("/");
+  std::error_code ec = make_error_code(std::errc::invalid_argument);
+  s = fs::space("/", ec);
+  VERIFY( !ec );
+
+  s = fs::space(__gnu_test::nonexistent_path(), ec);
+  VERIFY( ec );
+  VERIFY( s.capacity ==  static_cast<uintmax_t>(-1) );
+  VERIFY( s.free ==  static_cast<uintmax_t>(-1) );
+  VERIFY( s.available ==  static_cast<uintmax_t>(-1) );
+}
+
+void
+test02()
+{
+  fs::space_info s = fs::space(".");
+  VERIFY( s.capacity >= s.free );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}