svn commit: r210616 - stable/8/bin/sh

[jhell]

On 07/30/2010 09:56, Jilles Tjoelker wrote:
> On Thu, Jul 29, 2010 at 07:46:20PM -0400, jhell wrote:
>> So what has been commited here is implicitly stating that instead of
>> using ( trap 'exit 1' 2 ) in a script to catch SIGINT and exit it is now
>> being done on behalf of the user with no way for them to control it ?
> 
> No, this commit only changes something for interactive mode. It
> basically tries to create similar behaviour as the lines above (which
> have been in place for longer) but for the case with job control.
> 
> The lines above do have an effect in non-interactive mode, for example:
>   sh -c 'ftp; echo continued'
> Even if ^C has been typed in ftp(1), the shell continues. If a trap has
> been set on SIGINT, the code has no effect as int_pending is not set in
> that case.
> 
>> Basically this has the same effect on a script that uses ( && ) and to
>> which now have the same meaning.
> 
>> This script should print "PRINTME" twice when ^C during the sleep.
> 
>> #!/bin/sh
>> sleep 5000; echo "PRINTME"
>> echo "PRINTME"
> 
> No, this script should print nothing. This follows from common sense
> (users should be able to abort scripts unless those scripts do something
> to prevent it). A more technical explanation: because job control is not
> enabled, sh and sleep are in the same process group and therefore both
> receive terminal signals. Because sleep exited on the SIGINT, sh should
> exit on it, too.
> 
>> Whereas this script with the old behavior would have done what is trying
>> to be done now for the first line but should still print only the second
>> "PRINTME" during a ^C of sleep.
> 
>> #!/bin/sh
>> sleep 5000 && echo "PRINTME"
>> echo "PRINTME"
> 
> This should not print anything either, for the same reasons.
> 
>> And this script should not print anything when ^C is used during sleep.
>> #!/bin/sh
>> trap 'exit 1' 2
>> sleep 5000 ; echo "PRINTME"
>> echo "PRINTME"
> 
> Correct.
> 
>> What is being done currently on stable/8 is incorrect...
> 

Thank you for you explanation with these. I was confusing the way SIGINT
should be handled compared to how ";" is supposed to act. I did some
tests against some other shells to and to my surprise they confirmed the
same behavior that we have now which is correct.


Thanks again & much appreciated,

-- 

 jhell,v