2018-11-13 08:51:50

by Yury Norov

Subject: [PATCH RESEND] UAPI: move RENAME_* definitions to separated file

Discussion:
https://lore.kernel.org/lkml/20180702084622.GA15274@yury-thinkpad/

Although RENAME_* macros are exposed in kernel headers, they are not
used by glibc. That's because linux/fs.h which hosts RENAME_* is
considered unsuitable by glibc developers:

As Florian Weimer wrote:

> <linux/fs.h> undefines and defines macros not mentioned in the standards
> (and it even contains a few unrelated structs), so we cannot include it
> without _GNU_SOURCE.
>
> It might be possible to include it only for _GNU_SOURCE, but there are a
> lot of things in <linux/fs.h>, so that does not seem to be particularly
> advisable.

In this patch RENAME_* is removed to separated header file that
conforms standards and therefore is suitable for inclusion by glibc.

Signed-off-by: Yury Norov <[email protected]>
---
include/uapi/linux/fs.h | 4 +---
include/uapi/linux/rename.h | 12 ++++++++++++
2 files changed, 13 insertions(+), 3 deletions(-)
create mode 100644 include/uapi/linux/rename.h

diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 53a22e8e0408..dbf58bbf5bad 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -44,9 +44,7 @@
#define SEEK_HOLE 4 /* seek to the next hole */
#define SEEK_MAX SEEK_HOLE

-#define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */
-#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */
-#define RENAME_WHITEOUT (1 << 2) /* Whiteout source */
+#include <linux/rename.h>

struct file_clone_range {
__s64 src_fd;
diff --git a/include/uapi/linux/rename.h b/include/uapi/linux/rename.h
new file mode 100644
index 000000000000..7178f0565657
--- /dev/null
+++ b/include/uapi/linux/rename.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_RENAME_H
+#define _UAPI_LINUX_RENAME_H
+
+/*
+ * Definitions for rename syscall family.
+ */
+#define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */
+#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */
+#define RENAME_WHITEOUT (1 << 2) /* Whiteout source */
+
+#endif /* _UAPI_LINUX_RENAME_H */
--
2.17.1

2018-11-13 11:11:04

by Florian Weimer

Subject: Re: [PATCH RESEND] UAPI: move RENAME_* definitions to separated file

* Yury Norov:

> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index 53a22e8e0408..dbf58bbf5bad 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h

Could you move it to a dedicated <linux/rename-flags.h> header? Or add
a comment that the header is only for rename flags?

Then we can change glibc to include it if it is present and when
compiling under _GNU_SOURCE.

Thanks,
Florian