Finding a process ID given a socket and inode in Python 3

Question

/proc/net/tcp gives me a local address, port, and inode number for a socket (0.0.0.0:5432 and 9289, for example).

I'd like to find the PID for a specific process, given the above information.

It's possible to open every numbered folder in /proc, and then check symlinks for matching socket/inode numbers with a shell command like "$ sudo ls -l /proc/*/fd/ 2>/dev/null | grep socket". However, this seems more computationally expensive than necessary, since <5% of the processes on any given system have open TCP sockets.

What's the most efficient way to find the PID which has opened a given socket? I'd prefer to use standard libraries, and I'm currently developing with Python 3.2.3.

Edit: Removed the code samples from the question, since they are now included in the answer below.

Answer 1

The following code accomplishes the original goal:

def find_pid(inode):

    # get a list of all files and directories in /proc
    procFiles = os.listdir("/proc/")

    # remove the pid of the current python process
    procFiles.remove(str(os.getpid()))

    # set up a list object to store valid pids
    pids = []

    for f in procFiles:
        try:
            # convert the filename to an integer and back, saving the result to a list
            integer = int(f)
            pids.append(str(integer))
        except ValueError:
            # if the filename doesn't convert to an integer, it's not a pid, and we don't care about it
            pass

    for pid in pids:
        # check the fd directory for socket information
        fds = os.listdir("/proc/%s/fd/" % pid)
        for fd in fds:
            # save the pid for sockets matching our inode
            if ('socket:[%d]' % inode) == os.readlink("/proc/%s/fd/%s" % (pid, fd)):
                return pid