Avoid leaking handles across processes

test/libc/thread/pthread_atfork_test.c

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+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/dce.h"
+#include "libc/mem/gc.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/internal.h"
+#include "libc/stdio/lock.internal.h"
+#include "libc/testlib/subprocess.h"
+#include "libc/testlib/testlib.h"
+#include "libc/thread/thread.h"
+#include "third_party/nsync/mu.h"
+
+int Ai;
+const char *A[16];
+
+// clang-format off
+void prepare1(void) { A[Ai++] = "prepare1"; }
+void prepare2(void) { A[Ai++] = "prepare2"; }
+void parent1(void) { A[Ai++] = "parent1"; }
+void parent2(void) { A[Ai++] = "parent2"; }
+void child1(void) { A[Ai++] = "child1"; }
+void child2(void) { A[Ai++] = "child2"; }
+// clang-format on
+
+void *ForceThreadingMode(void *arg) {
+  return 0;
+}
+
+TEST(pthread_atfork, test) {
+  __enable_threads();
+  SPAWN(fork);
+  ASSERT_EQ(0, pthread_atfork(prepare1, parent1, child1));
+  ASSERT_EQ(0, pthread_atfork(prepare2, parent2, child2));
+  flockfile(stdout);
+  SPAWN(fork);
+  flockfile(stdout);
+  ASSERT_STREQ("prepare2", A[0]);
+  ASSERT_STREQ("prepare1", A[1]);
+  ASSERT_STREQ("child1", A[2]);
+  ASSERT_STREQ("child2", A[3]);
+  funlockfile(stdout);
+  EXITS(0);
+  funlockfile(stdout);
+  ASSERT_STREQ("prepare2", A[0]);
+  ASSERT_STREQ("prepare1", A[1]);
+  ASSERT_STREQ("parent1", A[2]);
+  ASSERT_STREQ("parent2", A[3]);
+  EXITS(0);
+}
+
+pthread_mutex_t mu;
+
+void mu_lock(void) {
+  pthread_mutex_lock(&mu);
+}
+
+void mu_unlock(void) {
+  pthread_mutex_unlock(&mu);
+}
+
+void mu_funlock(void) {
+  pthread_mutex_init(&mu, 0);
+}
+
+void *Worker(void *arg) {
+  for (int i = 0; i < 20; ++i) {
+    mu_lock();
+    usleep(20);
+    mu_unlock();
+    SPAWN(fork);
+    mu_lock();
+    usleep(1);
+    mu_unlock();
+    mu_lock();
+    mu_unlock();
+    EXITS(0);
+    mu_lock();
+    mu_unlock();
+  }
+  return 0;
+}
+
+TEST(pthread_atfork, torture) {
+  pthread_mutex_init(&mu, 0);
+  pthread_atfork(mu_lock, mu_unlock, mu_funlock);
+  int i, n = 4;
+  pthread_t *t = _gc(malloc(sizeof(pthread_t) * n));
+  for (i = 0; i < n; ++i) {
+    ASSERT_EQ(0, pthread_create(t + i, 0, Worker, 0));
+  }
+  for (i = 0; i < n; ++i) {
+    ASSERT_EQ(0, pthread_join(t[i], 0));
+  }
+}