Re: EXIT trap is not executed after an exec failure in a non-interactive shell

[Alex fxmbsw7 Ratchev]

any current standing point of 'ipc can not be done' alike whatsoever
wont be standing for too long in any case, just a question of time

On Sun, Oct 10, 2021 at 2:06 PM Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com> wrote:
>
> maybe the same way to implent here a fix may do IPC between bashes ?
> a meta database of stuff used in scripts, then if exec reset meta'ly
> to none ( undo em maybe .. i have to figure such for my bashlinker
> project too ) and if that fails restore em back
> the same meta db can be used in IPC somehowly.. important feature, i
> bet in 20 - 40 years there wont be bash without IPC, too bad it takes
> so long..
>
> is it cause posix isnt so far specifying everything for you ?
>
> On Fri, Oct 8, 2021 at 8:34 PM Mark March <march@systempad.org> wrote:
> >
> > >I'll look at changing that
> >
> > Thank you. I agree, making traps behave the same after an exec failure as 
> > after any other failed builtin is a better course of action. It will make 
> > the trap facility stronger. execve failures are not that uncommon, and are 
> > hard to predict in advance. execve(2) man page lists 24 failure conditions! 
> > Since they can't predict exec failures, scripts that use traps and must 
> > handle exec failures will have to save the traps before pretty much every 
> > call to exec that takes a command name. This is quite a bit of work to put 
> > on bash users. On the other hand, not doing this will lead to subtle bugs 
> > where cleanup code will suddenly not run, or processes unexpectedly catch 
> > signals that have been previously blocked.
> >
> > -Mark
> >
> >
> >
> > On Friday, October 8, 2021, 08:02:31 AM PDT, Chet Ramey 
> > <chet.ramey@case.edu> wrote:
> >
> >
> >
> >
> >
> > On 10/1/21 2:16 PM, Mark March wrote:
> > > Ok, thank you for clarifying. There is nothing in the documentation about 
> > > this behavior as far as I can tell. I would suggest adding a line about 
> > > traps getting reset after a failed exec to the paragraph on 'execfail'.
> >
> > I think it will be a cleaner fix, and more intuitive, to make sure the
> > traps are preserved across a failed `exec'. I'll look at changing that
> >
> > behavior.
> >
> > Chet
> >
> > --
> > ``The lyf so short, the craft so long to lerne.'' - Chaucer
> >         ``Ars longa, vita brevis'' - Hippocrates
> > Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/
> >
> >