#!/usr/bin/env python3
"""Run one child and report its wait4 peak RSS without /usr/bin/time."""
import os
import resource
import sys
import time

if len(sys.argv) < 2:
    raise SystemExit("usage: MeasureProcess.py executable [arguments ...]")

address_limit, _ = resource.getrlimit(resource.RLIMIT_AS)
stack_limit, _ = resource.getrlimit(resource.RLIMIT_STACK)
if address_limit in (resource.RLIM_INFINITY, -1) or address_limit > 6 * 1024**3:
    raise SystemExit("run under prlimit --as=6442450944")
if stack_limit in (resource.RLIM_INFINITY, -1) or stack_limit < 64 * 1024**2:
    raise SystemExit("run under prlimit --stack=67108864:67108864")
if not os.sched_getaffinity(0).issubset(set(range(12))):
    raise SystemExit("run under taskset -c 0-11")
print(f"[ProcessLimits] address_limit={address_limit} stack_limit={stack_limit} affinity={sorted(os.sched_getaffinity(0))}", flush=True)

started = time.monotonic()
pid = os.fork()
if pid == 0:
    try:
        os.execvp(sys.argv[1], sys.argv[1:])
    except OSError as error:
        print(f"MeasureProcess: exec failed: {error}", file=sys.stderr, flush=True)
        os._exit(127)

_, status, usage = os.wait4(pid, 0)
wall = time.monotonic() - started
exit_code = os.waitstatus_to_exitcode(status)
print(f"[ProcessResources] exit_code={exit_code} wall_s={wall:.6f} peak_rss_kib={usage.ru_maxrss}", flush=True)
raise SystemExit(exit_code)