[LTP] [PATCH v4] syscalls/xattr: Add runtime probe for socket xattr backports

[Cyril Hrubis]

Hi!
>  	socket_xattr_supported = tst_kvercmp(7, 1, 0) >= 0;
> +
> +	/*
> +	 * Commit dc0876b9846d "xattr: support extended attributes on sockets"
> +	 * merged in 7.1 mainline, but might be backported.
> +	 * Try to set xattr on socket to detect support.
> +	 */
> +	if (!socket_xattr_supported) {
> +		for (i = 0; i < ARRAY_SIZE(tc); i++) {
> +			if (tc[i].issocket) {
> +				socket_idx = i;
> +				break;
> +			}
> +		}
> +
> +		if (socket_idx != ARRAY_SIZE(tc)) {
> +			if (fsetxattr(tc[socket_idx].fd, tc[socket_idx].key,
> +				      tc[socket_idx].value, tc[socket_idx].size,
> +				      tc[socket_idx].flags) == 0) {
> +				tst_res(TINFO, "Socket xattr support detected (backport)");
> +				socket_xattr_supported = true;
> +
> +				SAFE_FREMOVEXATTR(tc[socket_idx].fd, tc[socket_idx].key);
> +			}

Instead of looking up the attribute in the array we can just create a
socket, try ato add an attribute and remove the socked instead. With
that we can up the code into a common header so that it's not duplicated
int two testcases. I guess that the best place would be the
lapi/socket.h header and we should add a static inline function
socket_xattrs_supported() there.

> +		}
> +	}
>  }
>  
>  static void cleanup(void)
> diff --git a/testcases/kernel/syscalls/setxattr/setxattr02.c b/testcases/kernel/syscalls/setxattr/setxattr02.c
> index 994ab655d..167e068cf 100644
> --- a/testcases/kernel/syscalls/setxattr/setxattr02.c
> +++ b/testcases/kernel/syscalls/setxattr/setxattr02.c
> @@ -196,6 +196,20 @@ static void setup(void)
>  	SAFE_MKNOD(SOCK, S_IFSOCK | 0777, 0);
>  
>  	socket_xattr_supported = tst_kvercmp(7, 1, 0) >= 0;
> +
> +	/*
> +	 * Commit dc0876b9846d "xattr: support extended attributes on sockets"
> +	 * merged in 7.1 mainline, but might be backported.
> +	 * Try to set xattr on socket to detect support.
> +	 */
> +	if (!socket_xattr_supported) {
> +		if (setxattr(SOCK, XATTR_TEST_KEY, XATTR_TEST_VALUE,
> +			     XATTR_TEST_VALUE_SIZE, XATTR_CREATE) == 0) {
> +			tst_res(TINFO, "Socket xattr support detected (backport)");
> +			socket_xattr_supported = true;
> +			SAFE_REMOVEXATTR(SOCK, XATTR_TEST_KEY);
> +		}
> +	}
>  }
>  
>  static struct tst_test test = {
> -- 
> 2.54.0.929.g9b7fa37559-goog
> 

-- 
Cyril Hrubis
chrubis@suse.cz