[Toybox] [PATCH] toysh: fix -Wuse-after-free

[Rob Landley]

On 3/22/24 10:26, enh wrote:
> On Fri, Mar 22, 2024 at 8:24 AM enh <enh at google.com> wrote:
>> (tbh, just merging "lsb" into "other" would be a step forwards. wtf
>> is/was "lsb" anyway? and while i can _usually_ guess "POSIX or not?"
>> correctly, "lsb or other" is impossible by virtue of being
>> meaningless.)
> 
> (and to be clear, although "lsb" is particularly obscure, i think this
> is the same problem busybox's organization has: why do i have to care
> whether something is in coreutils or linux-utils or procps? how is
> that relevant to me?

There's a reason I didn't use that as an organizing method. Although I did try
to map them at the end of the roadmap, and need to redo that analysis now since
it's been a while...

> the best answer i can think of is "because i want
> to only use toybox/busybox to replace _that_ package", but i don't
> think the _directory structure_ helps there, right? that hypothetical
> person actually wants more metadata in the kconfig part of the comment
> inside each file?)

That's the theoretical use, yes. So distros (and system builders like gentoo,
buildroot, yocto, etc) can annotate package alternatives so if you want to
install busybox's tar instead of gnu tar your package management system could
cope. In practice, making something like dpkg handle that was near impossible,
and buildroot only did it because the maintainer of busybox created buildroot. I
tried to add toybox to buildroot years ago and...

https://lists.buildroot.org/pipermail/buildroot/2014-September/409298.html

People still try from time to time:

https://lists.buildroot.org/pipermail/buildroot/2017-January/181960.html
http://lists.busybox.net/pipermail/buildroot/2022-September/652474.html

But even a build system that ALREADY lets you swap in/out buildroot vs gnu
versions of packages accomplished that by hardwiring busybox support deep into
its build system.

Getting something like debian to do that on the fly is... it's not really
designed for it.

I can think of better ways to do it (and am studying debian's build system in my
copious free time), but I've been busy with other things and most people aren't
motivated to try...

I note that I did it by hand back when creating aboriginal linux, which is what
led me to maintaining busybox in the first place, ala:

https://landley.net/aboriginal/old/

> When the Firmware Linux project started, busybox applets like sed and sort
> weren't powerful enough to handle the "./configure; make; make install" of
> packages like binutils or gcc. Busybox was usable in an embedded router or
> rescue floppy, but trying to get real work done with it revealed numerous
> bugs and limitations.
> 
> Busybox has now been fixed, and in Firmware Linux Busybox functions as an
> effective replacement for bzip2, coreutils, e2fsprogs, file, findutils, gawk,
> grep, inetutils, less, modutils, net-tools, patch, procps, sed, shadow,
> sysklogd, sysvinit, tar, util-linux, and vim. (Eventually, it should be
> capable of replacing bash and diffutils as well, but it's not there yet.)

That's the old page from before I restarted the project and renamed it
Aboriginal Linux (based on QEMU instead of User Mode Linux, ala
https://landley.net/notes-2005.html#27-10-2005). Before that I was going though
the Linux From Scratch package list and _disposing_ of gnu packages, one by one,
as I got busybox to replace them.

But "dpkg-query -S $(which $NAME)" is pretty easy to do the mapping yourself on
debian...

Rob