Re: [PATCH] tests/qtest/vhost-user-blk-test: Check whether qemu-storage-daemon is available

[Peter Maydell]

On Wed, 11 Aug 2021 at 11:00, Thomas Huth <thuth@redhat.com> wrote:
>
> The vhost-user-blk-test currently hangs if QTEST_QEMU_STORAGE_DAEMON_BINARY
> points to a non-existing binary. Let's improve this situation by checking
> for the availability of the binary first, so we can fail gracefully if
> it is not accessible.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  tests/qtest/vhost-user-blk-test.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/tests/qtest/vhost-user-blk-test.c 
> b/tests/qtest/vhost-user-blk-test.c
> index 8796c74ca4..6f108a1b62 100644
> --- a/tests/qtest/vhost-user-blk-test.c
> +++ b/tests/qtest/vhost-user-blk-test.c
> @@ -789,6 +789,14 @@ static const char *qtest_qemu_storage_daemon_binary(void)
>          exit(0);
>      }
>
> +    /* If we've got a path to the binary, check whether we can access it */
> +    if (strchr(qemu_storage_daemon_bin, '/') &&
> +        access(qemu_storage_daemon_bin, X_OK) != 0) {
> +        fprintf(stderr, "ERROR: '%s' is not accessible\n",
> +                qemu_storage_daemon_bin);
> +        exit(1);
> +    }

It makes sense not to bother starting the test if the binary isn't
even present, but why does the test hang? Shouldn't QEMU cleanly
exit rather than hanging if it turns out that it can't contact
the daemon ?

-- PMM