[Toybox] default SIGPIPE handler that calls _exit(0)?

[enh]

works for me, thanks. the comment isn't quite right though. patch attached.

On Fri, Feb 10, 2017 at 2:39 PM, Rob Landley <rob at landley.net> wrote:
> On 02/09/2017 03:50 PM, enh wrote:
>> this just came up again. the (internal) bug report being "`ps -A |
>> head -n1` shouldn't die with SIGPIPE".
>>
>> i think from this thread we agreed that there shouldn't be any
>> top-level SIGPIPE handler, with grep being an example where SIGPIPE is
>> the least worst choice.
>
> /me reads quoted message...
>
> Ah right, bionic adds a handler to turn this into an error message, then
> doesn't want it to be an error for toybox. Ok then.
>
> It looks like this commit:
>
> commit 483cfdabaf6ab282987a0a21d6177c3daa95dc12
> Author: Rob Landley <rob at landley.net>
> Date:   Sun May 3 20:18:53 2015 -0500
>
>     Replace android-specific hack with just signal(SIGPIPE, SIG_IGN).
>
> Got accidentally reverted in:
>
> commit 3b51a07e478d64a84e40b3a7c026b2f8566b194b
> Author: Rob Landley <rob at landley.net>
> Date:   Sun Sep 27 09:03:41 2015 -0500
>
>     Another chunk of nommu support, replacing toys.recursion with
>     toys.stacktop.
>
> Which doesn't even mention SIGPIPE.
>
> That said, SIGDFL is probably better than SIGIGN because we _do_ want it
> to kill the process. If we let toybox do the ferror() check on the way
> out it could report its own error condition.
>
>> so what about the specific case of ps? (as reported previously,
>> desktop ps seems to install a signal handler and _exit(0).)
>
> "Specific case of ps" is a red flag for me, seems like a generic problem
> needing a generic solution. The fflush() shenanigans in xprintf() and
> xexit() are so this:
>
>   $ ./ls -l > /dev/full
>   ls: write: No space left on device
>
> Gets caught. Not having ps/ls/cat report an error with SIGPIPE seems
> similarly generic.
>
> Rob



-- 
Elliott Hughes - http://who/enh - http://jessies.org/~enh/
Android native code/tools questions? Mail me/drop by/add me as a reviewer.
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