I need to find the device file (/dev/tty* or /dev/pts/*) connected to the standard input of any process on my system. I want to implement something similar to the tty(1) program but which works for any process. How do I do this? This is on Linux.
The closest I've gotten is to parse the /proc/pid/stat file and read out the 6th column. This gives me a number that corresponds to the st_rdev of the tty file I'm interested in. I then have to run stat(2) on all the /dev/tty* and /dev/pts/* files to get the st_rdev numbers and use that to map back. This is the approach used in the psutil package.
Update: I've taken a step back to reword this question into what I'm looking for rather than an implementation detail.
On Linux, you may just do ls -L /proc/pid/fd/0 to get the tty attached with the stdin of the process with process id pid.