1 files changed, 58 insertions, 0 deletions
diff --git a/sysdeps/posix/flock.c b/sysdeps/posix/flock.c
new file mode 100644
index 0000000000..b4c9fc3b79
--- /dev/null
+++ b/sysdeps/posix/flock.c
@@ -0,0 +1,58 @@
+/* Copyright (C) 1992, 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+/* This file implements the `flock' function in terms of the POSIX.1 `fcntl'
+   locking mechanism.  In 4BSD, these are two incompatible locking mechanisms,
+   perhaps with different semantics?  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/file.h>
+
+/* Apply or remove an advisory lock, according to OPERATION,
+   on the file FD refers to.  */
+int
+DEFUN(__flock, (fd, operation), int fd AND int operation)
+{
+  struct flock lbuf;
+
+  switch (operation & ~LOCK_NB)
+    {
+    case LOCK_SH:
+      lbuf.l_type = F_RDLCK;
+      break;
+    case LOCK_EX:
+      lbuf.l_type = F_WRLCK;
+      break;
+    case LOCK_UN:
+      lbuf.l_type = F_UNLCK;
+      break;
+    default:
+      errno = EINVAL;
+      return -1;
+    }
+
+  lbuf.l_whence = SEEK_SET;
+  lbuf.l_start = lbuf.l_len = 0L; /* Lock the whole file.  */
+
+  return __fcntl (fd, (operation & LOCK_NB) ? F_SETLK : F_SETLKW, &lbuf);
+}
+
+weak_alias (__flock, flock)