lava-test-runner shell script assumes 'read -t'

BTW I discovered yesterday that when reading stdin from a fifo, `read
-t` does not work at all, i.e. the timeout never happens.

`read -t 1 < /tmp/fifo` will block until there is something to be read
in the fifo.

This behaviour is consistent across busybox sh, bash and dash.

I am dropping the `-t N` in my branches.

On 12/19/2012 07:50 AM, Antonio Terceiro wrote:
> BTW I discovered yesterday that when reading stdin from a fifo, `read
> -t` does not work at all, i.e. the timeout never happens.
>
> `read -t 1 < /tmp/fifo` will block until there is something to be read
> in the fifo.
>
> This behaviour is consistent across busybox sh, bash and dash.

works in my version of bash and busybox (one from
http://busybox.net/downloads/binaries/1.20.0/):

  $ ./busybox-x86_64 sh
  $ read -t 3 blah || echo "timeout"
  timeout

> I am dropping the `-t N` in my branches.

seems risky to me

On Wed, Dec 19, 2012 at 06:41:06PM -0000, Andy Doan wrote:
> On 12/19/2012 07:50 AM, Antonio Terceiro wrote:
> > BTW I discovered yesterday that when reading stdin from a fifo, `read
> > -t` does not work at all, i.e. the timeout never happens.
> >
> > `read -t 1 < /tmp/fifo` will block until there is something to be read
> > in the fifo.
> >
> > This behaviour is consistent across busybox sh, bash and dash.
>
> works in my version of bash and busybox (one from
> http://busybox.net/downloads/binaries/1.20.0/):
>
> $ ./busybox-x86_64 sh
> $ read -t 3 blah || echo "timeout"
> timeout

Try this:

$ ./busybox-x86_64 sh
$ mkfifo /tmp/fifo
$ read -t 3 blah < /tmp/fifo || echo "timeout"

It doesn't work when reading stdin from a FIFO ...

--
Antonio Terceiro
Software Engineer - Linaro
http://www.linaro.org

Antonio Terceiro <email address hidden> writes:

> On Wed, Dec 19, 2012 at 06:41:06PM -0000, Andy Doan wrote:
>> On 12/19/2012 07:50 AM, Antonio Terceiro wrote:
>> > BTW I discovered yesterday that when reading stdin from a fifo, `read
>> > -t` does not work at all, i.e. the timeout never happens.
>> >
>> > `read -t 1 < /tmp/fifo` will block until there is something to be read
>> > in the fifo.
>> >
>> > This behaviour is consistent across busybox sh, bash and dash.
>>
>> works in my version of bash and busybox (one from
>> http://busybox.net/downloads/binaries/1.20.0/):
>>
>> $ ./busybox-x86_64 sh
>> $ read -t 3 blah || echo "timeout"
>> timeout
>
> Try this:
>
> $ ./busybox-x86_64 sh
> $ mkfifo /tmp/fifo
> $ read -t 3 blah < /tmp/fifo || echo "timeout"
>
> It doesn't work when reading stdin from a FIFO ...

FWIW, I see the same.