Clear flags2 flags set from mode in freopen (bug 32134)

[Joseph Myers]

As reported in bug 32134, freopen does not clear the flags set in
fp->_flags2 by the "e", "m" or "c" mode characters.  Clear these so
that they can be set or not as appropriate from the mode string passed
to freopen.  The relevant test for "e" in tst-freopen2-main.c is
enabled accordingly; "c" is expected to be covered in a separately
written test (and while tst-freopen2-main.c does include transitions
to and from "m", that's not really a semantic flag intended to result
in behaving in an observably different way).

Tested for x86_64.

diff --git a/libio/freopen.c b/libio/freopen.c
index c7e36db775..f6c943ddf8 100644
--- a/libio/freopen.c
+++ b/libio/freopen.c
@@ -63,6 +63,9 @@ freopen (const char *filename, const char *mode, FILE *fp)
 	 up here. */
       _IO_old_file_close_it (fp);
       _IO_JUMPS_FUNC_UPDATE (fp, &_IO_old_file_jumps);
+      fp->_flags2 &= ~(_IO_FLAGS2_MMAP
+		       | _IO_FLAGS2_NOTCANCEL
+		       | _IO_FLAGS2_CLOEXEC);
       result = _IO_old_file_fopen (fp, gfilename, mode);
     }
   else
@@ -72,6 +75,9 @@ freopen (const char *filename, const char *mode, FILE *fp)
       _IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps;
       if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
 	fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
+      fp->_flags2 &= ~(_IO_FLAGS2_MMAP
+		       | _IO_FLAGS2_NOTCANCEL
+		       | _IO_FLAGS2_CLOEXEC);
       result = _IO_file_fopen (fp, gfilename, mode, 1);
       if (result != NULL)
 	result = __fopen_maybe_mmap (result);
diff --git a/libio/freopen64.c b/libio/freopen64.c
index 9a6d5ed801..0f3cb16331 100644
--- a/libio/freopen64.c
+++ b/libio/freopen64.c
@@ -56,6 +56,9 @@ freopen64 (const char *filename, const char *mode, FILE *fp)
   _IO_JUMPS_FILE_plus (fp) = &_IO_file_jumps;
   if (_IO_vtable_offset (fp) == 0 && fp->_wide_data != NULL)
     fp->_wide_data->_wide_vtable = &_IO_wfile_jumps;
+  fp->_flags2 &= ~(_IO_FLAGS2_MMAP
+		   | _IO_FLAGS2_NOTCANCEL
+		   | _IO_FLAGS2_CLOEXEC);
   result = _IO_file_fopen (fp, gfilename, mode, 0);
   fp->_flags2 &= ~_IO_FLAGS2_NOCLOSE;
   if (result != NULL)
diff --git a/stdio-common/tst-freopen2-main.c b/stdio-common/tst-freopen2-main.c
index 22b21afebf..5dad41c76b 100644
--- a/stdio-common/tst-freopen2-main.c
+++ b/stdio-common/tst-freopen2-main.c
@@ -308,9 +308,7 @@ do_test (void)
   TEST_VERIFY_EXIT (fp != NULL);
   ret = fcntl (fileno (fp), F_GETFD);
   TEST_VERIFY (ret != -1);
-#if 0 /* Fails to clear FD_CLOEXEC (bug 32134).  */
   TEST_COMPARE (ret & FD_CLOEXEC, 0);
-#endif
   TEST_COMPARE_FILE_STRING (fp, "plustomore");
   xfclose (fp);
   END_TEST;

-- 
Joseph S. Myers
josmyers@redhat.com