On Thu, Nov 26, 2009 at 10:53 PM, Johannes Sixt <j6t@xxxxxxxx> wrote:
> On Donnerstag, 26. November 2009, Erik Faye-Lund wrote:
>> @@ -327,7 +327,10 @@ int start_async(struct async *async)
>> {
>> int pipe_out[2];
>>
>> - if (pipe(pipe_out) < 0)
>> + if (async->out) {
>> + pipe_out[0] = dup(async->out);
>> + pipe_out[1] = dup(async->out);
>> + } else if (pipe(pipe_out) < 0)
>> return error("cannot create pipe: %s", strerror(errno));
>> async->out = pipe_out[0];
>
> Hm. If async->out != 0:
>
> pipe_out[0] = dup(async->out);
> async->out = pipe_out[0];
>
> This is confusing.
What do you find confusing about it? The idea is to use a provided
bi-directional fd instead of a pipe if async->out is non-zero. The
currently defined rules for async is that async->out must be zero
(since the structure should be zero-initialized).
> Moreover, you are assigning (a dup of) the same fd to the writable end. This
> assumes a bi-directional channel. I don't yet know what I should think about
> this (haven't studied the later patches, yet).
>
Indeed it does. Do we want to extend it to support a set of
unidirectional channels instead?
> It would be great if you could add a few words to
> Documentation/technical/api-runcommand.txt.
>
Ah, yes. I know I should update the documentation and all, I'm just
usually really bad (*cough* lazy *cough*) at documenting stuff. But
I'll give it a go and if people hate what I write, they can suggest
changes.
--
Erik "kusma" Faye-Lund
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