[openwrt/openwrt] toolchain/musl: add support for renameat2()

[LEDE Commits]

ansuel pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/cc6a1e2abcdf32fc829755026f4dcb56d6dcde4a

commit cc6a1e2abcdf32fc829755026f4dcb56d6dcde4a
Author: Tony Ambardar <itugrok at yahoo.com>
AuthorDate: Tue Jun 11 22:30:48 2024 -0700

    toolchain/musl: add support for renameat2()
    
    Backport an upstream patch to support the renameat2 syscall, added in Linux
    3.15 and supported by glibc since 2.28. It is commonly used in filesystem
    or security contexts, and needed building upstream kernel bpf selftests.
    
    Link:
    https://inbox.vuxu.org/musl/20240421153640.379015-1-Tony.Ambardar@gmail.com/
    
    Signed-off-by: Tony Ambardar <itugrok at yahoo.com>
    Link: https://github.com/openwrt/openwrt/pull/15697
    Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
---
 .../610-add-renameat2-linux-syscall-wrapper.patch  | 61 ++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/toolchain/musl/patches/610-add-renameat2-linux-syscall-wrapper.patch b/toolchain/musl/patches/610-add-renameat2-linux-syscall-wrapper.patch
new file mode 100644
index 0000000000..167769360e
--- /dev/null
+++ b/toolchain/musl/patches/610-add-renameat2-linux-syscall-wrapper.patch
@@ -0,0 +1,61 @@
+From dc651fe2e6b16087c519c0bd0bf943cb7c53c807 Mon Sep 17 00:00:00 2001
+In-Reply-To: <20240423234355.2414567-1-Tony.Ambardar at gmail.com>
+References: <20240423234355.2414567-1-Tony.Ambardar at gmail.com>
+From: Tony Ambardar <Tony.Ambardar at gmail.com>
+Date: Sat, 20 Apr 2024 21:30:13 -0700
+Subject: [PATCH v3] add renameat2 linux syscall wrapper
+To: musl at lists.openwall.com
+Cc: Rich Felker <dalias at 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 at 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);
++}