148 lines
5.5 KiB
Python
148 lines
5.5 KiB
Python
"""
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父进程死亡防护（PR_SET_PDEATHSIG）测试
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背景与语义见 gateway/src/chongming/app/core/parent_death.py：进程树 onefile 引导 →
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granian master → worker（fork）。上游被 SIGKILL 时 worker 会成孤儿（继续监听
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端口、挂在服务发现里，其它网关派发到"半死副本"每次白吃 2 秒超时）。守卫让内核
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在父进程死亡时给本进程发 SIGTERM（走既有优雅停机摘除注册）。
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验证（三层 fork 复刻真实进程树：本测试(引导) → 中间进程(master) → 孙进程(worker)）：
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1. 关闭开关 CHONGMING_NO_PARENT_GUARD=1 → 不生效（返回 False）
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2. 中间进程 SIGKILL 自己（模拟 master 被 -9，内核不可捕获）→ 已设守卫的孙进程
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收到 SIGTERM 并退出
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3. 对照：同样结构但不设守卫 → 孙进程收不到信号（证明信号确实来自 PDEATHSIG，
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而不是别的东西清理孤儿）
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4. 幂等：重复调用不重复 prctl
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运行: uv run python test/test_parent_death.py
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"""
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import importlib.util
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import os
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import signal
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import sys
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import tempfile
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import time
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from pathlib import Path
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ROOT = Path(__file__).parent.parent
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_PD_PATH = ROOT / "gateway" / "src" / "chongming" / "app" / "core" / "parent_death.py"
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# 独立加载（parent_death 无包内依赖，避免连带导入整个 app 包）
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_spec = importlib.util.spec_from_file_location("chongming.app.core.parent_death", _PD_PATH)
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pd = importlib.util.module_from_spec(_spec)
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sys.modules["chongming.app.core.parent_death"] = pd
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_spec.loader.exec_module(pd) # type: ignore[union-attr]
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failures = []
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def check(name, cond, detail=""):
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status = "PASS" if cond else "FAIL"
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print(f"[{status}] {name}" + (f" — {detail}" if detail else ""))
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if not cond:
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failures.append(name)
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# ========== 1. 关闭开关 ==========
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os.environ[pd.GUARD_OFF_ENV] = "1"
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check("关闭开关打开时不生效", pd.guard_parent_death() is False)
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os.environ.pop(pd.GUARD_OFF_ENV, None)
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# ========== 2/3. 三层 fork：守卫组 / 对照组 ==========
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tmp = Path(tempfile.mkdtemp(prefix="parent_death_test_"))
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def scenario(name: str, use_guard: bool) -> dict:
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"""中间进程 SIGKILL 自己，观察孙进程是否收到 SIGTERM。"""
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d = tmp / name
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d.mkdir()
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ready, dead, pidf = d / "ready", d / "dead", d / "gc.pid"
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middle = os.fork()
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if middle == 0: # 中间进程（master 角色）
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gc = os.fork()
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if gc == 0: # 孙进程（worker 角色）
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def _on_term(*_):
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dead.write_text("term", encoding="utf-8")
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os._exit(0)
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signal.signal(signal.SIGTERM, _on_term)
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if use_guard:
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pd.guard_parent_death()
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pidf.write_text(str(os.getpid()), encoding="utf-8")
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ready.write_text("1", encoding="utf-8")
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time.sleep(15) # 等信号；超时说明没收到
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os._exit(1)
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for _ in range(250): # 等孙进程就绪，再硬杀自己
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if ready.exists():
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break
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time.sleep(0.02)
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os.kill(os.getpid(), signal.SIGKILL)
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os._exit(1) # 不会走到
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os.waitpid(middle, 0) # 中间进程必死于 SIGKILL
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gc_pid = int(pidf.read_text(encoding="utf-8"))
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for _ in range(100): # 最多等 5s
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if dead.exists():
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break
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time.sleep(0.05)
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got = dead.exists()
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try: # 清理（对照组孙进程仍活着）
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os.kill(gc_pid, signal.SIGKILL)
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except ProcessLookupError:
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pass
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return {"got_term": got, "gc_pid": gc_pid}
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guarded = scenario("guarded", use_guard=True)
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check(
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"master(SIGKILL) 死后，已设守卫的 worker 收到 SIGTERM 退出",
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guarded["got_term"],
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f"gc={guarded['gc_pid']}",
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)
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control = scenario("control", use_guard=False)
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check(
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"对照组（未设守卫）收不到信号 —— 证明退出确实来自 PDEATHSIG",
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not control["got_term"],
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f"gc={control['gc_pid']}",
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)
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# ========== 4. 幂等（在子进程里做：避免给测试进程本身设 PDEATHSIG） ==========
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pid = os.fork()
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if pid == 0:
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a = pd.guard_parent_death()
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b = pd.guard_parent_death()
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os._exit(0 if (a is True and b is True) else 1)
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_, status = os.waitpid(pid, 0)
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check("重复调用幂等（不重复 prctl）", os.waitstatus_to_exitcode(status) == 0)
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# ========== 5. fork 继承回归（master 先设 → worker 仍必须自己设上） ==========
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# 背景：若用模块级"已设置"标志位做幂等，fork 的子进程会继承 True 而短路——
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# 但内核在 fork 时恰好清零 PDEATHSIG，于是 worker 其实没设上（本轮实测到过）。
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# 这里父进程先真实设置，再 fork，断言子进程调用守卫时**内核状态确实被设上**。
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libc5 = pd._load_libc()
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pd.guard_parent_death() # 父进程（本测试进程）真实设置一次
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pid = os.fork()
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if pid == 0:
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cleared = pd._current_pdeathsig(libc5) == 0 # fork 后内核已清零（不继承）
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ok = pd.guard_parent_death() is True # 回归点：不能因父进程设过而短路
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set_now = pd._current_pdeathsig(libc5) == int(signal.SIGTERM)
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os._exit(0 if (cleared and ok and set_now) else 1)
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_, status = os.waitpid(pid, 0)
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libc5.prctl(pd._PR_SET_PDEATHSIG, 0) # 清除测试进程自己的设置，避免副作用
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check(
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"父进程设过后，fork 的子进程仍会真实设置 PDEATHSIG",
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os.waitstatus_to_exitcode(status) == 0,
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)
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import shutil
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shutil.rmtree(tmp, ignore_errors=True)
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print("\n" + ("=" * 40))
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if failures:
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print(f"❌ {len(failures)} 项未通过: {failures}")
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sys.exit(1)
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print("✅ 全部通过")
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