Re: [PATCH] Linux: Detect user namespace support in io/tst-getcwd-smallbuff

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

On 24/01/2022 20:13, Florian Weimer via Libc-alpha wrote:
> Otherwise the test fails with certain container runtimes.
> 

Thanks, you saved me a few hours; I was just looking at this :)  LGTM.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

> ---
>   sysdeps/unix/sysv/linux/tst-getcwd-smallbuff.c | 18 ++++++++++++++++++
>   1 file changed, 18 insertions(+)
> 
> diff --git a/sysdeps/unix/sysv/linux/tst-getcwd-smallbuff.c b/sysdeps/unix/sysv/linux/tst-getcwd-smallbuff.c
> index d460d6e766..55362f6060 100644
> --- a/sysdeps/unix/sysv/linux/tst-getcwd-smallbuff.c
> +++ b/sysdeps/unix/sysv/linux/tst-getcwd-smallbuff.c
> @@ -34,6 +34,7 @@
>   #include <sys/un.h>
>   #include <support/check.h>
>   #include <support/temp_file.h>
> +#include <support/test-driver.h>
>   #include <support/xsched.h>
>   #include <support/xunistd.h>
>   
> @@ -188,6 +189,23 @@ do_test (void)
>     xmkdir (MOUNT_NAME, S_IRWXU);
>     atexit (do_cleanup);
>   
> +  /* Check whether user namespaces are supported.  */
> +  {
> +    pid_t pid = xfork ();
> +    if (pid == 0)
> +      {
> +	if (unshare (CLONE_NEWUSER | CLONE_NEWNS) != 0)
> +	  _exit (EXIT_UNSUPPORTED);
> +	else
> +	  _exit (0);
> +      }
> +    int status;
> +    xwaitpid (pid, &status, 0);
> +    TEST_VERIFY_EXIT (WIFEXITED (status));
> +    if (WEXITSTATUS (status) != 0)
> +      return WEXITSTATUS (status);
> +  }
> +
>     TEST_VERIFY_EXIT (socketpair (AF_UNIX, SOCK_STREAM, 0, sockfd) == 0);
>     pid_t child_pid = xclone (child_func, NULL, child_stack,
>   			    sizeof (child_stack),
>