[CRIU] [PATCH 06/11] pstree: make equal_pid handle sid comparison between nested pidnses

[Dmitry Safonov]

2017-05-26 20:02 GMT+03:00 Pavel Tikhomirov <ptikhomirov at virtuozzo.com>:
> If process belonging to some session is in different pidns than leader
> of these session, it will have zeroes on all aditional levels in sid,
> so though levels for these process and leader does not match - sids do.
>
> Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
> ---
>  criu/include/pid.h | 34 ++++++++++++++++++++--------------
>  1 file changed, 20 insertions(+), 14 deletions(-)
>
> diff --git a/criu/include/pid.h b/criu/include/pid.h
> index 72f3636..b25621a 100644
> --- a/criu/include/pid.h
> +++ b/criu/include/pid.h
> @@ -46,20 +46,26 @@ struct pid {
>         } ns[1]; /* Must be at the end of struct pid */
>  };
>
> -#define equal_pid(a, b)                                                        \
> -({                                                                     \
> -       int ___i, ___ret = true;                                        \
> -       if (a->level == b->level) {                                     \
> -               for (___i = 0; ___i < a->level; ___i++)                 \
> -                       if (a->ns[___i].virt != b->ns[___i].virt) {     \
> -                               ___ret = false;                         \
> -                               ___i = a->level; /* break */            \
> -                       }                                               \
> -       } else {                                                        \
> -               pr_err("Wrong pid nesting level\n");                    \
> -               ___ret = false;                                         \
> -       }                                                               \
> -       ___ret;                                                         \
> +#define equal_pid(a, b)                                                                \
> +({                                                                             \
> +       int ___i, ___ret = true;                                                \
> +       struct pid *___a = a, *___b = b;                                        \
> +       if (a->level > b->level) {                                              \
> +               ___a = b;                                                       \
> +               ___b = a;                                                       \
> +               }                                                               \
> +       for (___i = 0; ___i < ___b->level; ___i++)                              \
> +               if (___i < ___a->level) {                                       \
> +                       if (___a->ns[___i].virt != ___b->ns[___i].virt) {       \
> +                               ___ret = false;                                 \
> +                               ___i = ___b->level; /* break */                 \
> +                               }                                               \
> +                       }                                                       \
> +               else if (___b->ns[___i].virt != 0) {                            \
> +                       ___ret = false;                                         \
> +                       ___i = ___b->level; /* break */                         \
> +                       }                                                       \
> +       ___ret;                                                                 \
>  })

I almost wish we hadn't gone down that macros-hole - and yet
and yet - it's rather curious, you know, this sort of life!

Is there any reason for it not to be a static inline function?

>
>  static inline pid_t last_level_pid(struct pid *pid)
> --
> 2.9.3
>
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-- 
             Dmitry