PR libfortran/64770 Segfault when trying to open existing file with status="new".

libgfortran ChangeLog:

2015-01-24  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/64770
	* io/unit.c (filename_from_unit): Check that u->filename != NULL
	before calling strdup.

testsuite ChangeLog:

2015-01-24  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/64770
	* gfortran.dg/open_new_segv.f90: New test.

From-SVN: r220086

gcc/testsuite/ChangeLog

+2015-01-24  Janne Blomqvist  <jb@gcc.gnu.org>
+
+	PR libfortran/64770
+	* gfortran.dg/open_new_segv.f90: New test.
+
 2015-01-24  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	PR target/49263

gcc/testsuite/gfortran.dg/open_new_segv.f90

+! { dg-do run }
+! PR 64770 SIGSEGV when trying to open an existing file with status="new"
+program pr64770
+  implicit none
+  ! Make sure pr64770test.dat exists
+  open(99, file="pr64770test.dat", status="replace")
+  close(99)
+  open(99, file="pr64770test.dat", access="stream", form="unformatted", &
+       status="new")
+end program pr64770

libgfortran/ChangeLog

+2015-01-24  Janne Blomqvist  <jb@gcc.gnu.org>
+
+	PR libfortran/64770
+	* io/unit.c (filename_from_unit): Check that u->filename != NULL
+	before calling strdup.
+
 2015-01-22  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/61933

libgfortran/io/unit.c

@@ -829,7 +829,7 @@ filename_from_unit (int n)
     }
 
   /* Get the filename.  */
-  if (u != NULL)
+  if (u != NULL && u->filename != NULL)
     return strdup (u->filename);
   else
     return (char *) NULL;