[LTP] [PATCH v1 2/2] lib: moves test infrastructure states into a shared context structure

[Cyril Hrubis]

Hi!
>  	if (tst_test->needs_checkpoints) {
> -		tst_futexes = (char *)results + sizeof(struct results);
> -		tst_max_futexes = (size - sizeof(struct results))/sizeof(futex_t);
> +		tst_futexes = ipc->futexes;
> +
> +		size_t futexes_offset = (char *)ipc->futexes - (char *)ipc;
> +		tst_max_futexes = (size - futexes_offset) / sizeof(futex_t);
                                           ^
					   This would be better as:
					   offsetof(struct ipc, futexes)
>  	}
>  
> -	memset(results, 0 , size);
> -	results->lib_pid = getpid();
> +	/* Set environment variable for exec()'d children */
> +	if (tst_test->needs_checkpoints || tst_test->child_needs_reinit) {
> +		snprintf(ipc_path, sizeof(ipc_path), IPC_ENV_VAR "=%s", shm_path);
> +		putenv(ipc_path);
> +	} else {
> +		SAFE_UNLINK(shm_path);
> +	}
>  }
>  
>  static void cleanup_ipc(void)
> @@ -157,9 +175,11 @@ static void cleanup_ipc(void)
>  	if (shm_path[0] && !access(shm_path, F_OK) && unlink(shm_path))
>  		tst_res(TWARN | TERRNO, "unlink(%s) failed", shm_path);
>  
> -	if (results) {
> -		msync((void *)results, size, MS_SYNC);
> -		munmap((void *)results, size);
> +	if (ipc) {
> +		msync((void *)ipc, size, MS_SYNC);
> +		munmap((void *)ipc, size);
> +		ipc = NULL;
> +		context = NULL;
>  		results = NULL;
>  	}
>  }
> @@ -177,12 +197,22 @@ void tst_reinit(void)
>  		tst_brk(TBROK, "File %s does not exist!", path);
>  
>  	fd = SAFE_OPEN(path, O_RDWR);
> +	ipc = SAFE_MMAP(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
> +	SAFE_CLOSE(fd);
>  
> -	results = SAFE_MMAP(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
> -	tst_futexes = (char *)results + sizeof(struct results);
> -	tst_max_futexes = (size - sizeof(struct results))/sizeof(futex_t);
> +	if (ipc->magic != LTP_MAGIC)
> +		tst_brk(TBROK, "Invalid shared memory region (bad magic)");
>  
> -	SAFE_CLOSE(fd);
> +	/* Restore the parent context from IPC region */
> +	context = &ipc->context;
> +	results = &ipc->results;
> +
> +	tst_futexes = ipc->futexes;
> +	size_t futexes_offset = (char *)ipc->futexes - (char *)ipc;
> +	tst_max_futexes = (size - futexes_offset) / sizeof(futex_t);
                                   ^
				   Here as well.

> +	if (context->tdebug)
> +		tst_res(TINFO, "tst_reinit(): restored metadata for PID %d", getpid());
>  }
>  
>  extern char **environ;
> @@ -236,19 +266,19 @@ static void update_results(int ttype)
>  
>  	switch (ttype) {
>  	case TCONF:
> -		tst_atomic_inc(&results->skipped);
> +		tst_atomic_inc((int *)&results->skipped);
>  	break;
>  	case TPASS:
> -		tst_atomic_inc(&results->passed);
> +		tst_atomic_inc((int *)&results->passed);
>  	break;
>  	case TWARN:
> -		tst_atomic_inc(&results->warnings);
> +		tst_atomic_inc((int *)&results->warnings);
>  	break;
>  	case TFAIL:
> -		tst_atomic_inc(&results->failed);
> +		tst_atomic_inc((int *)&results->failed);
>  	break;
>  	case TBROK:
> -		tst_atomic_inc(&results->broken);
> +		tst_atomic_inc((int *)&results->broken);
>  	break;

This gets ugly. I guess that it would be better to keep the results as
int unless we change the tst_atomic.h to work with int32_t.

Maybe we can actually drop the assembly fallbacks from tst_atomic.h
since as far as I can tell the __atomic_*() functions were added to
gcc-4.7 and the __sync_*() function were added into gcc-4.1 so unless we
need to support compiler older than 4.1 we can drop the assembly and
easily add support for atomic operations for int32_t.

-- 
Cyril Hrubis
chrubis@suse.cz