[Qemu-devel] [PATCH] linux-user: Assert on bad type in thunk_type_align() and thunk_type_size()

[Qemu-devel] [PATCH] linux-user: Assert on bad type in thunk_type_align() and thunk_type_size()

[Peter Maydell]

In thunk_type_align() and thunk_type_size() we currently return
-1 if the value at the type_ptr isn't one of the TYPE_* values
we understand. However, this should never happen, and if it does
then the calling code will go confusingly wrong because none
of the callsites try to handle an error return. Switch to an
assertion instead, so that if this does somehow happen we'll have
a nice clear backtrace of what happened rather than a weird crash
or misbehaviour.

This also silences various Coverity complaints about not handling
the negative return value (CID 1005735, 1005736, 1005738, 1390582).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 include/exec/user/thunk.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/exec/user/thunk.h b/include/exec/user/thunk.h
index f19ef4b230..840d6d899b 100644
--- a/include/exec/user/thunk.h
+++ b/include/exec/user/thunk.h
@@ -135,7 +135,7 @@ static inline int thunk_type_size(const argtype *type_ptr, int is_host)
         se = struct_entries + type_ptr[1];
         return se->size[is_host];
     default:
-        return -1;
+        g_assert_not_reached();
     }
 }
 
@@ -173,7 +173,7 @@ static inline int thunk_type_align(const argtype *type_ptr, int is_host)
         se = struct_entries + type_ptr[1];
         return se->align[is_host];
     default:
-        return -1;
+        g_assert_not_reached();
     }
 }
 
-- 
2.17.0

Re: [Qemu-devel] [PATCH] linux-user: Assert on bad type in thunk_type_align() and thunk_type_size()

[Laurent Vivier]

Le 14/05/2018 à 19:46, Peter Maydell a écrit :
> In thunk_type_align() and thunk_type_size() we currently return
> -1 if the value at the type_ptr isn't one of the TYPE_* values
> we understand. However, this should never happen, and if it does
> then the calling code will go confusingly wrong because none
> of the callsites try to handle an error return. Switch to an
> assertion instead, so that if this does somehow happen we'll have
> a nice clear backtrace of what happened rather than a weird crash
> or misbehaviour.
> 
> This also silences various Coverity complaints about not handling
> the negative return value (CID 1005735, 1005736, 1005738, 1390582).
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  include/exec/user/thunk.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Laurent Vivier <laurent@vivier.eu>