Question

In Perl, I need to read the environment of other processes.

• The script is running with root privileges.
• The script will be running in both Linux and Solaris.
• I would like a solution that’s mostly platform agnostic, at least between Linux and Solaris. In Linux, examining the /env/<proc_id>/environ can get me the answer.
• I would like to avoid having to fork. I already have a solution forking ‘/usr/ucb/ps -auxwwwe $pid’

Any ideas?

Answer 1

For Solaris, you could try the procfs module from CPAN. Even though this module still seems quite young, this quote sounds hopeful:

Brian Farrell sent a very useful patch which handles inspection of argv and environment of processes other than the currently running process.

I imagine that this is probably just the initial environment (just like the environ file under linux), but that seems to be what you want?

Otherwise, although I see you say you don’t want to fork, a simple solution would probably to crank ~20 lines of C to produce a small program that just spits out the environment on Solaris as the exact equivalent of the Linux environ file. I have something very similar in C already. If you’re interested, I can post it.

EDIT (after reading OpenSolaris pargs.c): The environment buffer is reallocated under Solaris when the environment changes, so the psinfo pointer may be invalid. For a bullet proof solution, you need to hunt down _environ. That’s all probably more hassle than you need… pargs -e <pid> might be a nicer alterative to UCB ps(1) if you do go the fork route, though.