Re: [PATCH 2/2] kconfig: echo stdin to stdout if either is redirected

From: Masahiro Yamada
Date: Thu Feb 08 2018 - 01:55:01 EST


2018-02-08 15:51 GMT+09:00 Ulf Magnusson <ulfalizer@xxxxxxxxx>:
> On Thu, Feb 8, 2018 at 7:35 AM, Ulf Magnusson <ulfalizer@xxxxxxxxx> wrote:
>> On Thu, Feb 8, 2018 at 6:56 AM, Masahiro Yamada
>> <yamada.masahiro@xxxxxxxxxxxxx> wrote:
>>> If stdio is not tty, conf_askvalue() puts additional new line to
>>> prevent prompts are all concatenated into a single line. This care
>>> is missing in conf_choice(), so a 'choice' prompt and the next prompt
>>> are shown in the same line.
>>>
>>> Move the code into xfgets() to take care of all cases. To improve
>>> this more, echo stdin to stdout. This clarifies what keys were input
>>> from stdio and the stdout looks like as if it were from tty.
>>>
>>> I removed the isatty(2) check since stderr is unrelated here.
>>>
>>> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
>>> ---
>>>
>>> scripts/kconfig/conf.c | 7 ++++---
>>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
>>> index 358e2e4..c5318d3 100644
>>> --- a/scripts/kconfig/conf.c
>>> +++ b/scripts/kconfig/conf.c
>>> @@ -76,6 +76,9 @@ static void xfgets(char *str, int size, FILE *in)
>>> {
>>> if (!fgets(str, size, in))
>>> fprintf(stderr, "\nError in reading or end of file.\n");
>>> +
>>> + if (!tty_stdio)
>>> + printf("%s", str);
>>> }
>>>
>>> static int conf_askvalue(struct symbol *sym, const char *def)
>>> @@ -106,8 +109,6 @@ static int conf_askvalue(struct symbol *sym, const char *def)
>>> case oldaskconfig:
>>> fflush(stdout);
>>> xfgets(line, sizeof(line), stdin);
>>> - if (!tty_stdio)
>>> - printf("\n");
>>> return 1;
>>> default:
>>> break;
>>> @@ -495,7 +496,7 @@ int main(int ac, char **av)
>>> bindtextdomain(PACKAGE, LOCALEDIR);
>>> textdomain(PACKAGE);
>>>
>>> - tty_stdio = isatty(0) && isatty(1) && isatty(2);
>>> + tty_stdio = isatty(0) && isatty(1);
>>>
>>> while ((opt = getopt_long(ac, av, "s", long_opts, NULL)) != -1) {
>>> if (opt == 's') {
>>> --
>>> 2.7.4
>>>
>>
>> Reviewed-by: Ulf Magnusson <ulfalizer@xxxxxxxxx>
>>
>> Might be some case I'm not thinking of, but wouldn't it make sense to
>> just check isatty(1) as well? If stdout is a regular file, it seems
>> it'd be nice to have the input appear there, regardless of where stdin
>> is from.
>>
>> Maybe the tty_stdio variable could be removed then as well, replaced
>> with just 'if (!isatty(1))'.
>>
>> Cheers,
>> Ulf
>
> Hmm... if stdout is a tty and stdin isn't, this would prevent the
> input from showing up on the terminal though, so I guess it makes
> sense.

Yes. I want to address this case too.

Anyway, thank you for checking the details!




> That case seems more important than the weird
> stdin=tty/stdout=file case.
>
> Tricky stuff. :)
>
> Cheers,
> Ulf
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--
Best Regards
Masahiro Yamada