Re: [LTP] [PATCH] syscalls: fix testcases which take TCONF as TFAIL

[Xiaoguang W. <wan...@cn...>]

Hi,

On 07/01/2014 09:55 PM, ch...@su... wrote:

>> +	} else {
>> +		tst_brkm(TBROK, cleanup, "child process terminated "
>> +				 "abnormally. status: %d", status);
>> +	}
> 
> The child code uses exit(1) directly, which coincidentally maps to the
> TFAIL but we should be consistent and better use 1 here or TFAIL in the
> child code.
> 
> Also this would be better written as a switch statement
> 
> 	switch (ret) {
> 	case TPASS:
> 		...
> 	break;
> 	case TCONF:
> 		...
> 	break;
> 	default:
> 		tst_resm(TFAIL, "...");
> 	}

OK. And I'd like to introduce two new function tst_reset_exitval() and tst_record_childstatus().
Here are some explanations:
Some test cases need do real test work in child process and parent process deal with the test results.
Usually it is not recommended to use tst_* interfaces in child process, because child process's test
results are not propagated to parent process correctly. But if child process call tst_exit() to report
the test results, I think it is OK.

And the big problem prohibits us to call tst_brkm(cleanup, ...) in child process is that child
and parent process share the directory created by tst_tmpdir(). Though child and parent process
share many other kernel resources, but mostly they are based on kernel COW mechanism. So if we can
remove the tst_rmdir() operation in cleanup() or put it elsewhere, I think we are free to call
tst_brkm(cleanup,..) interface, thanks.

If later we need do real test work in child process, the code flow would be:
child:
	tst_reset_exitval()
	...
	tst_resm(...) //record test resutls
	...
	tsr_brkm(...) //terminate the test
	...
	tst_exit()

parent:
	wait(child)
	tst_record_childstatus()


Regards,
Xiaoguang Wang 
>