Re: bash 3.2.39 -- race condition

[Douglas Moyes]

Chet Ramey wrote:
> Douglas Moyes wrote:
>   
> > I nearly brought down a server today.
> >
> > # alias d="perl-script "
> > ....
> >
> > # d() {
> > # perl-script $1 |grep something|cut -d ' ' -f 3
> > # }
> > # d something
> > ..... ..... .... CRASH
> >
> > turns out bash went into a loop calling d over and over again, which
> > resulted in thousands of grep, bash, and -d processes being executed. It
> > wasn't pretty.
> >     
>
> You defined `perl-script' as a recursive function (alias expansion is
> performed when a function is defined) and called it.  I'm not surprised
> at the result.
>
> Chet
>
>   

So... what you're saying is that this:

# alias d="dh-machine "
# d() {
# dh-machine $1 |grep something|cut -d ' ' -f 3
# }

became this:

# alias d="dh-machine "
# dh-machine() {
# dh-machine $1 |grep something|cut -d ' ' -f 3
# }

And bash didn't treat d() as a a unique identifier because it tokenized 
d and (), then expanded 'd' as an alias. Okay, I see how that makes the 
interpreter simpler, but it's not that intuitive and most likely would 
always be an undesired effect. It would be more intuitive if "xxxx() {" 
ignored any previous definition of xxxx.