Hello ALexander,

On Mon, 10 May 2021 at 05:20, Alexander Monakov [off-list ref] wrote:

On Mon, 10 May 2021, Michael Kerrisk (man-pages) via Libc-alpha wrote:

quoted

Hello,

On Fri, 7 May 2021 at 02:21, Dave Chupreev [off-list ref] wrote:

quoted

Well I see, I've tried on Linux and yea I didn't find any option to insert multiple definitions.

I think the only way to insert multiple definitions is by direct
manipulation of 'extern char **environ'.

You can cause a program to start with multiple definitions, because it is
possible to pass arbitrarily funny stuff as 'envp' argument to execve, such as:

- duplicated entries
- entries without a '='
- entries starting with '='
- empty strings
- "2 x 2 = 4"

All of that will be present in the exec'd program's environment array.

Yes. I was too focussed on thinking about what an already running
program can do to its current environment. Thanks for reminding me of
the above.

Thanks,

Michael


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/