Re: [PATCH] public/io: xs_wire: Allow Xenstore to report EPERM

[Juergen Gross]

On 27.06.22 12:00, Julien Grall wrote:

Hi Jan,

On 27/06/2022 07:57, Jan Beulich wrote:

On 24.06.2022 18:51, Julien Grall wrote:

--- a/xen/include/public/io/xs_wire.h
+++ b/xen/include/public/io/xs_wire.h
@@ -76,6 +76,7 @@ static struct xsd_errors xsd_errors[]
  __attribute__((unused))
  #endif
      = {
+    XSD_ERROR(EPERM),
      XSD_ERROR(EINVAL),
      XSD_ERROR(EACCES),
      XSD_ERROR(EEXIST),

Inserting ahead of EINVAL looks to break xenstored_core.c:send_error(),

:(.

which - legitimately or not - assumes EINVAL to be first.

I will also move EPERM towards the end (I added first because EPERM is 1).

I am not sure who else is relying on this. So I would consider this to be bake in the ABI. I think the minimum is to add a BUILD_BUG_ON() in send_error().

I agree to both plans.


Juergen

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