Add renameat2 function [BZ #17662]

The implementation falls back to renameat if renameat2 is not available
in the kernel (or in the kernel headers) and the flags argument is zero.
Without kernel support, a non-zero argument returns EINVAL, not ENOSYS.
This mirrors what the kernel does for invalid renameat2 flags.

1 files changed, 12 insertions, 0 deletions

diff --git a/libio/stdio.h b/libio/stdio.h
index 731f8e56f4..739e08610d 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -153,6 +153,18 @@ extern int renameat (int __oldfd, const char *__old, int __newfd,
 		     const char *__new) __THROW;
 #endif
 
+#ifdef __USE_GNU
+/* Flags for renameat2.  */
+# define RENAME_NOREPLACE (1 << 0)
+# define RENAME_EXCHANGE (1 << 1)
+# define RENAME_WHITEOUT (1 << 2)
+
+/* Rename file OLD relative to OLDFD to NEW relative to NEWFD, with
+   additional flags.  */
+extern int renameat2 (int __oldfd, const char *__old, int __newfd,
+		      const char *__new, unsigned int __flags) __THROW;
+#endif
+
 /* Create a temporary file and open it read/write.
 
    This function is a possible cancellation point and therefore not