1 files changed, 76 insertions, 0 deletions
diff --git a/libc/sysdeps/unix/sysv/linux/readv.c b/libc/sysdeps/unix/sysv/linux/readv.c
new file mode 100644
index 000000000..250c00a07
--- /dev/null
+++ b/libc/sysdeps/unix/sysv/linux/readv.c
@@ -0,0 +1,76 @@
+/* readv supports all Linux kernels >= 2.0.
+   Copyright (C) 1997,1998,2000,2002,2003 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 <stddef.h>
+#include <sys/param.h>
+#include <sys/uio.h>
+
+#include <sysdep-cancel.h>
+#include <sys/syscall.h>
+#include <bp-checks.h>
+
+static ssize_t __atomic_readv_replacement (int, __const struct iovec *,
+					   int) internal_function;
+
+
+/* Not all versions of the kernel support the large number of records.  */
+#ifndef UIO_FASTIOV
+# define UIO_FASTIOV	8	/* 8 is a safe number.  */
+#endif
+
+
+/* We should deal with kernel which have a smaller UIO_FASTIOV as well
+   as a very big count.  */
+static ssize_t
+do_readv (int fd, const struct iovec *vector, int count)
+{
+  ssize_t bytes_read;
+
+  bytes_read = INLINE_SYSCALL (readv, 3, fd, CHECK_N (vector, count), count);
+
+  if (bytes_read >= 0 || errno != EINVAL || count <= UIO_FASTIOV)
+    return bytes_read;
+
+  return __atomic_readv_replacement (fd, vector, count);
+}
+
+
+ssize_t
+__libc_readv (fd, vector, count)
+     int fd;
+     const struct iovec *vector;
+     int count;
+{
+  if (SINGLE_THREAD_P)
+    return do_readv (fd, vector, count);
+
+  int oldtype = LIBC_CANCEL_ASYNC ();
+
+  int result = do_readv (fd, vector, count);
+
+  LIBC_CANCEL_RESET (oldtype);
+
+  return result;
+}
+strong_alias (__libc_readv, __readv)
+weak_alias (__libc_readv, readv)
+
+#define __libc_readv static internal_function __atomic_readv_replacement
+#include <sysdeps/posix/readv.c>