1 files changed, 136 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..0b61315
--- /dev/null
+++ b/lib/libc/stdio/_flock_stub.c
@@ -0,0 +1,136 @@
+/*
+ * 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. 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.
+ */
+
+/*
+ * POSIX stdio FILE locking functions. These assume that the locking
+ * is only required at FILE structure level, not at file descriptor
+ * level too.
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include "un-namespace.h"
+
+#include "local.h"
+
+
+/*
+ * Weak symbols for externally visible functions in this file:
+ */
+__weak_reference(_flockfile, flockfile);
+__weak_reference(_flockfile_debug_stub, _flockfile_debug);
+__weak_reference(_ftrylockfile, ftrylockfile);
+__weak_reference(_funlockfile, funlockfile);
+
+void
+_flockfile(FILE *fp)
+{
+	pthread_t curthread = _pthread_self();
+
+	if (fp->_fl_owner == curthread)
+		fp->_fl_count++;
+	else {
+		/*
+		 * Make sure this mutex is treated as a private
+		 * internal mutex:
+		 */
+		_pthread_mutex_lock(&fp->_fl_mutex);
+		fp->_fl_owner = curthread;
+		fp->_fl_count = 1;
+	}
+}
+
+/*
+ * This can be overriden by the threads library if it is linked in.
+ */
+void
+_flockfile_debug_stub(FILE *fp, char *fname, int lineno)
+{
+	_flockfile(fp);
+}
+
+int
+_ftrylockfile(FILE *fp)
+{
+	pthread_t curthread = _pthread_self();
+	int	ret = 0;
+
+	if (fp->_fl_owner == curthread)
+		fp->_fl_count++;
+	/*
+	 * Make sure this mutex is treated as a private
+	 * internal mutex:
+	 */
+	else if (_pthread_mutex_trylock(&fp->_fl_mutex) == 0) {
+		fp->_fl_owner = curthread;
+		fp->_fl_count = 1;
+	}
+	else
+		ret = -1;
+	return (ret);
+}
+
+void 
+_funlockfile(FILE *fp)
+{
+	pthread_t	curthread = _pthread_self();
+
+	/*
+	 * Check if this file is owned by the current thread:
+	 */
+	if (fp->_fl_owner == curthread) {
+		/*
+		 * Check if this thread has locked the FILE
+		 * more than once:
+		 */
+		if (fp->_fl_count > 1)
+			/*
+			 * Decrement the count of the number of
+			 * times the running thread has locked this
+			 * file:
+			 */
+			fp->_fl_count--;
+		else {
+			/*
+			 * The running thread will release the
+			 * lock now:
+			 */
+			fp->_fl_count = 0;
+			fp->_fl_owner = NULL;
+			_pthread_mutex_unlock(&fp->_fl_mutex);
+		}
+	}
+}