re PR libstdc++/26777 (sync_with_stdio(false) triggers bug with sgetc and pubseekoff)

2006-03-22  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/26777
	* include/bits/fstream.tcc (basic_filebuf<>::_M_seek): Check
	the return value of _M_file.seekoff.
	* testsuite/27_io/basic_filebuf/seekoff/char/26777.cc: New.

From-SVN: r112286

3 files changed, 103 insertions, 7 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 0ef887a..8a09057 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2006-03-22  Paolo Carlini  <pcarlini@suse.de>
+
+	PR libstdc++/26777
+	* include/bits/fstream.tcc (basic_filebuf<>::_M_seek): Check
+	the return value of _M_file.seekoff.
+	* testsuite/27_io/basic_filebuf/seekoff/char/26777.cc: New.
+
 2006-03-21  Paolo Carlini  <pcarlini@suse.de>
 
 	PR libstdc++/25482
diff --git a/libstdc++-v3/include/bits/fstream.tcc b/libstdc++-v3/include/bits/fstream.tcc
index 08fcdbe..5520f9b 100644
--- a/libstdc++-v3/include/bits/fstream.tcc
+++ b/libstdc++-v3/include/bits/fstream.tcc
@@ -1,6 +1,6 @@
 // File based streams -*- C++ -*-
 
-// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -740,12 +740,15 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
 	{
 	  // Returns pos_type(off_type(-1)) in case of failure.
 	  __ret = pos_type(_M_file.seekoff(__off, __way));
-	  _M_reading = false;
-	  _M_writing = false;
-	  _M_ext_next = _M_ext_end = _M_ext_buf;
-	  _M_set_buffer(-1);
-	  _M_state_cur = __state;
-	  __ret.state(_M_state_cur);
+	  if (__ret != pos_type(off_type(-1)))
+	    {
+	      _M_reading = false;
+	      _M_writing = false;
+	      _M_ext_next = _M_ext_end = _M_ext_buf;
+	      _M_set_buffer(-1);
+	      _M_state_cur = __state;
+	      __ret.state(_M_state_cur);
+	    }
 	}
       return __ret;
     }
diff --git a/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/26777.cc b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/26777.cc
new file mode 100644
index 0000000..7312ce2
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/basic_filebuf/seekoff/char/26777.cc
@@ -0,0 +1,86 @@
+// { dg-require-fork "" }
+// { dg-require-mkfifo "" }
+
+// 2006-03-22  Paolo Carlini  <pcarlini@suse.de>
+
+// Copyright (C) 2006 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 2, 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 COPYING.  If not, write to the Free
+// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+#include <testsuite_hooks.h>
+#include <fstream>
+#include <sstream>
+#include <unistd.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+// libstdc++/26777
+void test01()
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  bool test __attribute__((unused)) = true;
+
+  const char* name = "tmp_fifo6";
+
+  signal(SIGPIPE, SIG_IGN);
+
+  unlink(name);  
+  mkfifo(name, S_IRWXU);
+  semaphore s1, s2;
+
+  int child = fork();
+  VERIFY( child != -1 );
+
+  if (child == 0)
+    {
+      filebuf fbout;
+      fbout.open(name, ios_base::in | ios_base::out);
+      VERIFY( fbout.is_open() );
+      fbout.sputn("Whatever", 8);
+      fbout.pubsync();
+      s1.signal();
+      s2.wait();
+      fbout.close();
+      s1.signal();
+      exit(0);
+    }
+
+  filebuf fbin;
+  fbin.open(name, ios::in);
+  s1.wait();
+
+  fbin.sgetc();
+  fbin.pubseekoff(0, ios::cur, ios::in);
+  s2.signal();
+  s1.wait();
+
+  ostringstream oss;
+  oss << &fbin;
+  fbin.close();
+
+  VERIFY( oss.str() == "Whatever" );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}