Add FILE locking stubs for libc.

Change the FILE locking to support kernel threads when linked with
libpthread (which you haven't see yet). This requires that libc become
thread-safe and thread-aware, testing __isthreaded before attempting
to do lock/unlock calls. The impact on non-threaded programs is minor.
This change works with libc_r, so it's the best compromise.

1 files changed, 78 insertions, 0 deletions

diff --git a/lib/libc/stdio/_flock_stub.c b/lib/libc/stdio/_flock_stub.c
new file mode 100644
index 0000000..5915c46
--- /dev/null
+++ b/lib/libc/stdio/_flock_stub.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by John Birrell.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $Id$
+ *
+ */
+
+#include <stdio.h>
+
+/*
+ * Declare weak references in case the application is not linked
+ * with libpthread.
+ */
+#pragma weak _flockfile=_flockfile_stub
+#pragma weak _flockfile_debug=_flockfile_debug_stub
+#pragma weak _ftrylockfile=_ftrylockfile_stub
+#pragma weak _funlockfile=_funlockfile_stub
+
+/*
+ * This function is a stub for the _flockfile function in libpthread.
+ */
+void
+_flockfile_stub(FILE *fp)
+{
+}
+
+/*
+ * This function is a stub for the _flockfile_debug function in libpthread.
+ */
+void
+_flockfile_debug_stub(FILE *fp, char *fname, int lineno)
+{
+}
+
+/*
+ * This function is a stub for the _ftrylockfile function in libpthread.
+ */
+int
+_ftrylockfile_stub(FILE *fp)
+{
+	return(0);
+}
+
+/*
+ * This function is a stub for the _funlockfile function in libpthread.
+ */
+void
+_funlockfile_stub(FILE *fp)
+{
+}