Re: [Xenomai-core] [PATCH 2/2] Provide owner name via rt_mutex_inquire

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Jan Kiszka wrote:
> This can be helpful for debugging the (futile) release attempts of
> mutexes by tasks that do not own them.
> 
> Returning the RT_TASK reference may appear more consistent on first
> sight, but it cannot be guaranteed that the owner is actually a native
> task. Therefore this patch uses the symbolic name.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
> ---
>  include/native/mutex.h    |    3 +++
>  ksrc/skins/native/mutex.c |    5 +++++
>  2 files changed, 8 insertions(+)
> 
> Index: b/include/native/mutex.h
> ===================================================================
> --- a/include/native/mutex.h
> +++ b/include/native/mutex.h
> @@ -38,6 +38,9 @@ typedef struct rt_mutex_info {
>  
>  	char name[XNOBJECT_NAME_LEN]; /**< Symbolic name. */
>  
> +	char owner[XNOBJECT_NAME_LEN]; /**< Symbolic name of the current owner,
> +					    empty if unlocked. */
> +
>  } RT_MUTEX_INFO;
>  
>  typedef struct rt_mutex_placeholder {
> Index: b/ksrc/skins/native/mutex.c
> ===================================================================
> --- a/ksrc/skins/native/mutex.c
> +++ b/ksrc/skins/native/mutex.c
> @@ -597,6 +597,11 @@ int rt_mutex_inquire(RT_MUTEX *mutex, RT
>  	strcpy(info->name, mutex->name);
>  	info->lockcnt = mutex->lockcnt;
>  	info->nwaiters = xnsynch_nsleepers(&mutex->synch_base);
> +	if (mutex->lockcnt)
> +		strcpy(info->owner,
> +		       xnthread_name(xnsynch_owner(&mutex->synch_base)));

xnthread_name is not necessarily null terminated, so I would suggest to use:

	snprintf(info->owner, sizeof(info->owner), "%s",
		 xnthread_name(xnsynch_owner(&mutex->synch_base)));

(and not strncpy, strncpy is crippled)

Another possibility would be to use snprintf instead of strncpy in 
xnobject_copy_name, and use xnobject_copy_name here.

-- 
                                                  Gilles.