openwrt/toolchain/musl/patches/610-add-renameat2-linux-sys...

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Diff

From dc651fe2e6b16087c519c0bd0bf943cb7c53c807 Mon Sep 17 00:00:00 2001
In-Reply-To: <20240423234355.2414567-1-Tony.Ambardar@gmail.com>
References: <20240423234355.2414567-1-Tony.Ambardar@gmail.com>
From: Tony Ambardar <Tony.Ambardar@gmail.com>
Date: Sat, 20 Apr 2024 21:30:13 -0700
Subject: [PATCH v3] add renameat2 linux syscall wrapper
To: musl@lists.openwall.com
Cc: Rich Felker <dalias@libc.org>
This syscall is available since Linux 3.15 and also implemented in glibc
from version 2.28. It is commonly used in filesystem or security contexts.
Constants RENAME_NOREPLACE, RENAME_EXCHANGE, RENAME_WHITEOUT are guarded by
_GNU_SOURCE as with glibc.
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
---
v2 -> v3:
* call SYS_renameat first if applicable
* drop unneeded error code handling
v1 -> v2:
* align related constants
* drop 'int' from 'unsigned int'
* add fallback to SYS_renameat where applicable
---
include/stdio.h | 7 +++++++
src/linux/renameat2.c | 11 +++++++++++
2 files changed, 18 insertions(+)
create mode 100644 src/linux/renameat2.c
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -158,6 +158,13 @@ char *ctermid(char *);
#define L_ctermid 20
#endif
+#if defined(_GNU_SOURCE)
+#define RENAME_NOREPLACE (1 << 0)
+#define RENAME_EXCHANGE (1 << 1)
+#define RENAME_WHITEOUT (1 << 2)
+
+int renameat2(int, const char *, int, const char *, unsigned);
+#endif
#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
|| defined(_BSD_SOURCE)
--- /dev/null
+++ b/src/linux/renameat2.c
@@ -0,0 +1,11 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include "syscall.h"
+
+int renameat2(int oldfd, const char *old, int newfd, const char *new, unsigned flags)
+{
+#ifdef SYS_renameat
+ if (!flags) return syscall(SYS_renameat, oldfd, old, newfd, new);
+#endif
+ return syscall(SYS_renameat2, oldfd, old, newfd, new, flags);
+}