run command with sudo su in script and redirect stdin and stdout

Question

I need to run command as another user and write to its stdin and read from its stdout. I can run command as another user only via opening new shell: sudo su anotheruser but with new opened shell i will lost stdin and stdout of caller. I am not allowed to run sudo -u anotheruser -c command

I found out that i can use named pipes for stdin/stdout redirection, so i wrote a script:

#!/usr/bin/env bash

mkfifo pipein
mkfifo pipeout

echo '/usr/lib/openssh/sftp-server 0<pipein >pipeout' | sudo su anotheruser

cat 0<&1 >pipein & cat <pipeout

wait

But it doesn't work as desired. I want to redirect script's stdin to command's stdin and also redirect command's stdout to script's stdout - so i could seamlessly use the script as original command.

Answer 1

You seem to have some editing errors in your post. There is a "&" missing for the sudo line, and you are using different names for your pipes later in the script. Here is something that works for me:

#!/usr/bin/env bash
mkfifo pipein
mkfifo pipeout
echo '/usr/lib/openssh/sftp-server <pipein >pipeout' | sudo su anotheruser &
cat <pipeout &
cat >pipein
wait
rm -f pipein pipeout

Answer 2

I'm not sure I understand your question completely but I think you are after something like this:

sudo -u $USER sh -c "ls -la /home" | grep $USER

Or if you want the pipe as the other user

sudo -u $USER sh -c "ls -la /home | grep $USER"