Re: [PATCH v2 3/3] selftests/nolibc: Add test for getcwd() and readlink()

["Thomas Weißschuh" <linux@weissschuh.net>]

Hi Daniel,

thanks for the patches!

On 2026-06-30 22:24:19+0900, Daniel Palmer wrote:
> Add a test that uses both getcwd() and readlink() so that both
> are exercised.
> 
> First the happy path is tested by fetching what should be the
> same string via getcwd() and readlink() and checking they match.
> 
> Then a few different combinations of bad parameters are passed to
> getcwd() to make sure it returns NULL and sets errno in those
> cases.

Sashiko found a few things. I think all of them are valid.
https://sashiko.dev/#/patchset/20260630132419.2523890-1-daniel%40thingy.jp

> Signed-off-by: Daniel Palmer <daniel@thingy.jp>
> ---
>  tools/testing/selftests/nolibc/nolibc-test.c | 48 ++++++++++++++++++++
>  1 file changed, 48 insertions(+)
> 
> diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
> index c1c1ce43a047..d54e7188e2ab 100644
> --- a/tools/testing/selftests/nolibc/nolibc-test.c
> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> @@ -854,6 +854,53 @@ static int test_dirent(void)
>  	return 0;
>  }
>  
> +static int test_getcwd(void)
> +{
> +	char cwd_syscall[1024];
> +	char cwd_proc[1024];
> +	ssize_t len;
> +
> +	/* Read where the link /proc/self/cwd points */
> +	len = readlink("/proc/self/cwd", cwd_proc, sizeof(cwd_proc) - 1);
> +	if (len <= 0)
> +		return -1;

Please return different values here, so it is obvious which subtest
failed.


> +
> +	/* Terminate the string from readlink() */
> +	cwd_proc[len] = '\0';
> +
> +	/* Get the cwd via syscall */
> +	if (getcwd(cwd_syscall, sizeof(cwd_syscall)) == NULL)
> +		return -1;

(...)