#!/usr/bin/env python3
"""Translate the trigger-count guest VA into a HOST address gdb can watch.

gdb debugs the host emulator process, so a guest VA is meaningless to it. Canary
backs guest memory with one shared-memory file, so the chain is:

    guest VA -> file offset            gmem.va_to_off
    file offset -> host address        the shm mapping in /proc/<pid>/maps,
                                       host = map_start - map_file_offset + off

Prints the host address on stdout, and the working on stderr.
"""
import os
import sys

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
import gmem
import isl
import squadron_state as S

ssb = isl.load('/tmp/Stage02.ssb')
path = gmem.mem_path()
size = os.path.getsize(path)
with open(path, 'rb', buffering=0) as f:
    m, _fb = S.find_mission(f, size, ssb)
    if m is None:
        print('NOTFOUND'); sys.exit(1)
    ph = S.u32(f, m + 4)

va = ph + 272 + 20
off = gmem.va_to_off(va)
shm = os.path.basename(path)
pids = [p for p in os.listdir('/proc') if p.isdigit()
        and os.path.exists('/proc/%s/comm' % p)
        and open('/proc/%s/comm' % p).read().strip() == 'xenia_canary']
if not pids:
    print('NOPID'); sys.exit(1)
host = None
for line in open('/proc/%s/maps' % pids[0]):
    if shm not in line:
        continue
    rng, _perm, mo = line.split()[0], line.split()[1], line.split()[2]
    a, b = (int(x, 16) for x in rng.split('-'))
    mo = int(mo, 16)
    if mo <= off < mo + (b - a):
        host = a - mo + off
        break
if host is None:
    print('NOMAP'); sys.exit(1)
print('mission 0x%08X phase 0x%08X va 0x%08X off 0x%X -> host 0x%X'
      % (m, ph, va, off, host), file=sys.stderr)
print('0x%X' % host)