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

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

May 2, 2026 09:25:45 Daniel Palmer <daniel@thingy.jp>:

> Add a test for getcwd() that uses readlink() so tests that
> at the same time.
>
> This is very basic, just getting what should be the same
> string via getcwd() and readlink() and then checking they
> are the same.
>
> Signed-off-by: Daniel Palmer <daniel@thingy.jp>
> ---
> tools/testing/selftests/nolibc/nolibc-test.c | 26 ++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
> index 08610cacf030..54513fb9a16a 100644
> --- a/tools/testing/selftests/nolibc/nolibc-test.c
> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> @@ -849,6 +849,31 @@ 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;
> +
> +   /* Terminate the string from readlink() */
> +   cwd_proc[len] = '\0';
> +
> +   /* Get the cwd via syscall */
> +   if (getcwd(cwd_syscall, sizeof(cwd_syscall)) == NULL)
> +       return -1;
> +
> +   /* Fail if they aren't the same */
> +   if (strcmp(cwd_proc, cwd_syscall) != 0)
> +       return -1;
> +
> +   return 0;
> +}
> +
> int test_getrandom(void)
> {
>     uint64_t rng = 0;
> @@ -1477,6 +1502,7 @@ int run_syscall(int min, int max)
>         CASE_TEST(clock_getres);      EXPECT_SYSZR(1, clock_getres(CLOCK_MONOTONIC, &ts)); break;
>         CASE_TEST(clock_gettime);     EXPECT_SYSZR(1, clock_gettime(CLOCK_MONOTONIC, &ts)); break;
>         CASE_TEST(clock_settime);     EXPECT_SYSER(1, clock_settime(CLOCK_MONOTONIC, &ts), -1, EINVAL); break;
> +       CASE_TEST(getcwd);            EXPECT_SYSZR(1, test_getcwd()); break;

EXPECT_SYSZR(proc, ...)

>         CASE_TEST(getpid);            EXPECT_SYSNE(1, getpid(), -1); break;
>         CASE_TEST(getppid);           EXPECT_SYSNE(1, getppid(), -1); break;
>         CASE_TEST(gettid);            EXPECT_SYSNE(has_gettid, gettid(), -1); break;
> --
> 2.53.0