implement readahead()

1 files changed, 52 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/common/readahead.c b/libc/sysdeps/linux/common/readahead.c
new file mode 100644
index 000000000..5220b5dc4
--- /dev/null
+++ b/libc/sysdeps/linux/common/readahead.c
@@ -0,0 +1,52 @@
+/* Provide kernel hint to read ahead.
+   Copyright (C) 2002, 2003, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <bits/wordsize.h>
+
+#ifdef __NR_readahead
+
+# define __NR___readahead __NR_readahead
+
+# if __WORDSIZE == 64
+
+static inline _syscall3(ssize_t, __readahead, int, fd,
+	off_t, offset, size_t, count);
+
+ssize_t readahead(int fd, off_t offset, size_t count)
+{
+	return __readahead(fd, offset, count);
+}
+
+# else
+
+static inline _syscall4(ssize_t, __readahead, int, fd,
+	off_t, high_offset, off_t, low_offset, size_t, count);
+
+ssize_t readahead(int fd, off64_t offset, size_t count)
+{
+	return __readahead(fd, (off_t) (offset >> 32), (off_t) (offset & 0xffffffff), count);
+}
+
+# endif
+
+#endif