#!/usr/bin/python
import sys
import os
import subprocess
 
POLICY_FILE_DIR="/etc/qubes_rpc/policy"
QREXEC_CLIENT="/usr/lib/qubes/qrexec_client"

def read_policy_file(exec_index):
    policy=list()
    f = open(POLICY_FILE_DIR+"/"+exec_index)
    for iter in f.readlines():
        policy.append(iter.split())
    f.close()
    return policy

def is_match(item, config_term):
    return (item is not "dom0" and config_term == "anyvm") or item == config_term

def apply_policy(policy, domain, target):
    for iter in policy:
        if len(iter) < 3:
            continue
        if not is_match(domain, iter[0]):
            continue
        if not is_match(target, iter[1]):
            continue
        ret=iter[2].split("=")
        if len(ret)==1:
            return (ret[0], None)
        else:
            return (ret[0], ret[1])
    return (None, None)
        
def do_execute(domain, target, exec_index, process_ident):
    if target == "dom0":
        cmd="/usr/lib/qubes/qubes_rpc_multiplexer "+exec_index + " " + domain
    elif target == "dispvm":
        cmd = "/usr/lib/qubes/qfile-daemon-dvm " + exec_index + " " + domain
    else:
#fixme: qvm-run --pass_io is broken for non-running target domain
        cmd= "qvm-run -uroot -q -a --pass_io "+target
        cmd+=" '/usr/lib/qubes/qubes_rpc_multiplexer "+exec_index + " " + domain + "'"
    os.execl(QREXEC_CLIENT, "qrexec_client", "-d", domain, "-l", cmd, "-c", process_ident)

def confirm_execution(domain, target, exec_index):
    text = "Do you allow domain \"" +domain + "\" to execute " + exec_index
    text+= " operation on the domain \"" + target +"\"?" 
    retcode = subprocess.call(["/usr/bin/zenity", "--question", "--text", text])
    return retcode==0

def policy_editor(domain, target, exec_index):
    text = "Policy editor not yet implemented. Please add a line in the form \""
    text+= domain + " " + target + "action_to_take\""
    text+= " to /etc/qubes_rpc/policy/" + exec_index +" file in dom0, then close this info."
    subprocess.call(["/usr/bin/zenity", "--info", "--text", text]) 

def main():
    domain=sys.argv[1]
    target=sys.argv[2]
    exec_index=sys.argv[3]
    process_ident=sys.argv[4]
    
    action = None
    while action is None:
        policy = read_policy_file(exec_index)
        (action, params) = apply_policy(policy, domain, target)
        if action is None:
            policy_editor(domain, target, exec_index)
    if action == "allow":
        do_execute(domain, target, exec_index, process_ident)
    elif action == "divert":
        do_execute(domain, params, exec_index, process_ident)
    elif action == "ask":
        if confirm_execution(domain, target, exec_index):
            do_execute(domain, target, exec_index, process_ident)
    print >> sys.stderr, "Rpc denied:", domain, target, exec_index    
    os.execl(QREXEC_CLIENT, "qrexec_client", "-d", domain, "-l", "/bin/false", "-c", process_ident)

main()