Using an ad-hoc libc with a tool which is an argument of another tool

Question

I need to use a particular libc to run a tool (cp). The problem is that this tool has to be used as argument of another tool (for example timeout) and I don't want to use the modified libc with this one.

I tried to do:

timeout 10 LD_LIBRARY_PATH=/path/to/mod/libc/ cp a b

But I received the error:

timeout: failed to run command 'LD_LIBRARY_PATH=/path/to/mod/libc/': No such file or directory

And, as I said, I can't do:

LD_LIBRARY_PATH=/path/to/mod/libc/ timeout 10 cp a b

as timeout would use the modified libc. Is there any way to do this?

Answer 1

You can achieve that by using the env utility:

timeout 10 /usr/bin/env LD_LIBRARY_PATH=/path/to/mod/libc/ cp a b

Env will set the environment variable and exec the other utility with that environment.