Re: ZSH crashed when reading bytes from a large binary

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Mon, Sep 12, 2022 at 12:37 AM Jun T <takimoto-j@xxxxxxxxxxxxxxxxx> wrote:
>
> > 2022/09/11 23:43, Liu, Song <songliu@xxxxxxx> wrote:
> >
> > The problem is that, when ZSH failed to reallocate memory, ZSH didn’t check the return value of `realloc` function and handle the error. This will make ZSH crash.
>
> There are many other places where the return value of realloc() is not checked.
> Can we simply replace them by zrealloc()?

Replacing them with zrealloc() will still result in immediate exit of
the shell, just with a different error message and no stack trace.

> > } else {
> > free(buf);
> > return EXIT_FAILURE;
> > }

The specific question here is whether having the "read" builtin return
failure at this point will allow the shell to recover from the
out-of-memory state, or whether it's just delaying the inevitable
death.  (Aside, we use EXIT_FAILURE exactly nowhere, so if we do not
exit, this should just be "return 1" as if end-of-file was encountered
per docs.)

In most cases we've assumed that once the shell is out of memory,
there's no way back, so how it dies is not that interesting.