lib/replace: add fallback defines for __NR_openat2

sys/syscall.h might be older than the runtime kernel.

If the kernel has support for openat2() we should
try to use if anyway.

The callers have to deal with ENOSYS anyway,
so there's no difference if we get that from syscall(__NR_openat2)
or directly from rep_openat2().

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

diff --git a/lib/replace/replace.c b/lib/replace/replace.c
index 5ec2f7ccc56ba81f484eca4786b4e7ffa15b502f..54d3a60e179d09d0432022473f0d02973567bc1b 100644 (file)
--- a/lib/replace/replace.c
+++ b/lib/replace/replace.c
@@ -1084,6 +1084,26 @@ ssize_t rep_copy_file_range(int fd_in,
 #endif /* HAVE_COPY_FILE_RANGE */
 
 #ifndef HAVE_OPENAT2
+
+/* fallback known wellknown __NR_openat2 values */
+#ifndef __NR_openat2
+# if defined(LINUX) && defined(HAVE_SYS_SYSCALL_H)
+#  if defined(__i386__)
+#   define __NR_openat2 437
+#  elif defined(__x86_64__) && defined(__LP64__)
+#   define __NR_openat2 437 /* 437 0x1B5 */
+#  elif defined(__x86_64__) && defined(__ILP32__)
+#   define __NR_openat2 1073742261 /* 1073742261 0x400001B5 */
+#  elif defined(__aarch64__)
+#   define __NR_openat2 437
+#  elif defined(__arm__)
+#   define __NR_openat2 437
+#  elif defined(__sparc__)
+#   define __NR_openat2 437
+#  endif
+# endif /* defined(LINUX) && defined(HAVE_SYS_SYSCALL_H) */
+#endif /* !__NR_openat2 */
+
 long rep_openat2(int dirfd, const char *pathname,
                 struct open_how *how, size_t size)
 {