[libvirt] [PATCH] util: correct retry path in virFileOperation

[Laine Stump]

On 03/02/2011 06:30 PM, Eric Blake wrote:
> In virFileOperation, the parent does a fallback to a non-fork
> attempt if it detects that the child returned EACCES.  However,
> the child was calling _exit(-EACCESS), which does _not_ appear
> as EACCES in the parent.
>
> * src/util/util.c (virFileOperation): Correctly pass EACCES from
> child to parent.
> ---
>   src/util/util.c |    9 +++++++++
>   1 files changed, 9 insertions(+), 0 deletions(-)
>
> diff --git a/src/util/util.c b/src/util/util.c
> index bac71c8..0fe1c41 100644
> --- a/src/util/util.c
> +++ b/src/util/util.c
> @@ -1559,6 +1559,15 @@ parenterror:
>           goto childerror;
>       }
>   childerror:
> +    /* Hook sets ret to -errno on failure, but exit must be positive.
> +     * If we exit with EACCES, then parent tries again.  */
> +    /* XXX This makes assumptions about errno being<  255, which is
> +     * not true on Hurd.  */
> +    ret = -ret;

Maybe just a matter of taste, but I think I would prefer if everywhere 
in virFileOperation set ret = errno (instead of -errno), and when hook 
is called, do "ret = - hook(...)". Then you don't need the extra "ret = 
-ret".

ACK either way, though.

> +    if ((ret&  0xff) != ret) {
> +        VIR_WARN("unable to pass desired return value %d", ret);
> +        ret = 0xff;
> +    }
>       _exit(ret);
>
>   }