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

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

[Florian Weimer]

Otherwise the test fails with certain container runtimes.

---
 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),

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

[Siddhesh Poyarekar]

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),
>