Roland, please ignore this and the next patch.
We can do the same without UTRACE_ATTACH_MATCH_CHECK.
I don't like to rely on ->cred_guard_mutex, but MATCH_CHECK is
not nice too.
On 10/09, Oleg Nesterov wrote:
>
> Implement UTRACE_ATTACH_MATCH_CHECK. With this flag utrace_attach_task(data)
> "data" is the function pointer which checks engine->data instead of simple
> comparison.
>
> Todo: comment + rename.
>
> ---
>
> include/linux/utrace.h | 1 +
> kernel/utrace.c | 5 +++++
> 2 files changed, 6 insertions(+)
>
> --- PU/include/linux/utrace.h~77_UTRACE_MATCH_FILTER 2009-10-09
> 18:51:56.000000000 +0200
> +++ PU/include/linux/utrace.h 2009-10-09 19:02:34.000000000 +0200
> @@ -303,6 +303,7 @@ static inline enum utrace_syscall_action
> #define UTRACE_ATTACH_EXCLUSIVE 0x0020 /* Refuse if existing
> match. */
> #define UTRACE_ATTACH_MATCH_OPS 0x0001 /* Match engines on ops.
> */
> #define UTRACE_ATTACH_MATCH_DATA 0x0002 /* Match engines on data. */
> +#define UTRACE_ATTACH_MATCH_CHECK 0x0004 /* Match engines on ????. */
> #define UTRACE_ATTACH_MATCH_MASK 0x000f
>
> /**
> --- PU/kernel/utrace.c~77_UTRACE_MATCH_FILTER 2009-10-09 18:51:56.000000000
> +0200
> +++ PU/kernel/utrace.c 2009-10-09 19:04:05.000000000 +0200
> @@ -92,6 +92,11 @@ static bool engine_matches(struct utrace
> return false;
> if ((flags & UTRACE_ATTACH_MATCH_DATA) && engine->data != data)
> return false;
> + if (flags & UTRACE_ATTACH_MATCH_CHECK) {
> + bool (*check)(void*) = data;
> + if (!check(engine->data))
> + return false;
> + }
> return engine->ops && engine->ops != &utrace_detached_ops;
> }
>
