Re: [Qemu-devel] [PATCH 3/4] pidfile: stop making pidfile error a special case

[Michael Tokarev]

31.10.2014 10:33, Gonglei wrote:
[]
>>>> While at it, fix wrong identation in os_daemonize().
>>>
>>> s/identation/identification/
>>
>> No, the original word was the right one.
> 
> Sorry, I can't find 'identation' both dictionary and Google.
> Your meaning 'indentation'?

Damn.  I missed that one.  It is "indentation" inedeed :)
(but not identification).

[]
>>>>              do {
>>>>                  len = read(fds[0], &status, 1);
>>>>              } while (len < 0 && errno == EINTR);
>>>> -            if (len != 1) {
>>>> -                exit(1);
>>>> -            }
>>>
>>> Does this check need to be removed?
>>
>> Yes, because...
>>>
>>>> -            else if (status == 1) {
>>>> -                fprintf(stderr, "Could not acquire pidfile\n");
>>>> -                exit(1);
>>>> -            } else {
>>>> -                exit(0);
>>>> -            }
>>>> -            } else if (pid < 0) {
>>>> -                exit(1);
>>>> -            }
>>>> +
>>>> +            exit(len == 1 && status == 0 ? 0 : 1);
>>
>> ...it is checked here, note the 'len == 1' part of the condition.
> 
> If len != 1, the original code exit with 1, after your changes,
> it will exit with 0. Right?

with len != 1, the condition 'len == 1 && status == 0 ? 0 : 1'
evaluates to 1.  Maybe I can add a comment here:

+            /* only exit successfully if our child actually
+             * wrote a one-byte zero to our pipe */
+            exit(len == 1 && status == 0 ? 0 : 1);

See the result at 
http://git.corpit.ru/?p=qemu.git;a=shortlog;h=refs/heads/trivial-patches-next

Thanks,

/mjt