nptl: Add tst-robust-fork

2 files changed, 186 insertions, 1 deletions

diff --git a/nptl/Makefile b/nptl/Makefile
index dcb5953325..2d38316291 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -295,7 +295,8 @@ tests = tst-typesizes \
 	tst-initializers1 $(addprefix tst-initializers1-,\
 			    c89 gnu89 c99 gnu99 c11 gnu11) \
 	tst-bad-schedattr \
-	tst-thread_local1 tst-mutex-errorcheck tst-robust10
+	tst-thread_local1 tst-mutex-errorcheck tst-robust10 \
+	tst-robust-fork
 xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \
 	tst-mutexpp1 tst-mutexpp6 tst-mutexpp10
 test-srcs = tst-oddstacklimit
diff --git a/nptl/tst-robust-fork.c b/nptl/tst-robust-fork.c
new file mode 100644
index 0000000000..4a12ff000d
--- /dev/null
+++ b/nptl/tst-robust-fork.c
@@ -0,0 +1,184 @@
+/* Test the interaction of fork and robust mutexes.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/test-driver.h>
+#include <support/xthread.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+
+/* Data shared between processes. */
+struct shared
+{
+  pthread_mutex_t parent_mutex;
+  pthread_mutex_t child_mutex;
+};
+
+/* These flags control which mutex settings are enabled in the parent
+   and child (separately).  */
+enum mutex_bits
+  {
+    mutex_pshared = 1,
+    mutex_robust = 2,
+    mutex_pi = 4,
+    mutex_check = 8,
+
+    /* All bits combined.  */
+    mutex_all_bits = 15,
+  };
+
+static void
+mutex_init (pthread_mutex_t *mutex, int bits)
+{
+  pthread_mutexattr_t attr;
+  xpthread_mutexattr_init (&attr);
+  if (bits & mutex_pshared)
+    xpthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED);
+  if (bits & mutex_robust)
+    xpthread_mutexattr_setrobust (&attr, PTHREAD_MUTEX_ROBUST);
+  if (bits & mutex_pi)
+    xpthread_mutexattr_setprotocol (&attr, PTHREAD_PRIO_INHERIT);
+  if (bits & mutex_check)
+    xpthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK);
+  xpthread_mutex_init (mutex, &attr);
+  xpthread_mutexattr_destroy (&attr);
+}
+
+static void
+one_test (int parent_bits, int child_bits, int nonshared_bits,
+          bool lock_nonshared, bool lock_child)
+{
+
+  struct shared *shared = xmmap (NULL, sizeof (*shared),
+                                 PROT_READ | PROT_WRITE,
+                                 MAP_ANONYMOUS | MAP_SHARED, -1);
+  mutex_init (&shared->parent_mutex, parent_bits);
+  mutex_init (&shared->child_mutex, child_bits);
+
+  /* Acquire the parent mutex in the parent.  */
+  xpthread_mutex_lock (&shared->parent_mutex);
+
+  pthread_mutex_t nonshared_mutex;
+  mutex_init (&nonshared_mutex, nonshared_bits);
+  if (lock_nonshared)
+    xpthread_mutex_lock (&nonshared_mutex);
+
+  pid_t pid = xfork ();
+  if (pid == 0)
+    {
+      /* Child process.  */
+      if (lock_child)
+        xpthread_mutex_lock (&shared->child_mutex);
+      else
+        xmunmap (shared, sizeof (*shared));
+      if (lock_nonshared)
+        /* Reinitialize the non-shared mutex if it was locked in the
+           parent.  */
+        mutex_init (&nonshared_mutex, nonshared_bits);
+      xpthread_mutex_lock (&nonshared_mutex);
+      /* For robust mutexes, the _exit call will perform the unlock
+         instead.  */
+      if (lock_child && !(child_bits & mutex_robust))
+        xpthread_mutex_unlock (&shared->child_mutex);
+      _exit (0);
+    }
+  /* Parent process. */
+  {
+    int status;
+    xwaitpid (pid, &status, 0);
+    TEST_VERIFY (status == 0);
+  }
+
+  if (parent_bits & mutex_check)
+    /* Test for expected self-deadlock.  This is only possible to
+       detect if the mutex is error-checking.  */
+    TEST_VERIFY_EXIT (pthread_mutex_lock (&shared->parent_mutex) == EDEADLK);
+
+  pid = xfork ();
+  if (pid == 0)
+    {
+      /* Child process.  We can perform some checks only if we are
+         dealing with process-shared mutexes.  */
+      if (parent_bits & mutex_pshared)
+        /* It must not be possible to acquire the parent mutex.
+
+           NB: This check touches a mutex which has been acquired in
+           the parent at fork time, so it might be deemed undefined
+           behavior, pending the resolution of Austin Groups issue
+           1112.  */
+        TEST_VERIFY_EXIT (pthread_mutex_trylock (&shared->parent_mutex)
+                          == EBUSY);
+      if (lock_child && (child_bits & mutex_robust))
+        {
+          if (!(child_bits & mutex_pshared))
+            /* No further tests possible.  */
+            _exit (0);
+          TEST_VERIFY_EXIT (pthread_mutex_lock (&shared->child_mutex)
+                            == EOWNERDEAD);
+          xpthread_mutex_consistent (&shared->child_mutex);
+        }
+      else
+        /* We did not acquire the lock in the first child process, or
+           we unlocked the mutex again because the mutex is not a
+           robust mutex.  */
+        xpthread_mutex_lock (&shared->child_mutex);
+      xpthread_mutex_unlock (&shared->child_mutex);
+      _exit (0);
+    }
+  /* Parent process. */
+  {
+    int status;
+    xwaitpid (pid, &status, 0);
+    TEST_VERIFY (status == 0);
+  }
+
+  if (lock_nonshared)
+    xpthread_mutex_unlock (&nonshared_mutex);
+  xpthread_mutex_unlock (&shared->parent_mutex);
+  xpthread_mutex_destroy (&shared->parent_mutex);
+  xpthread_mutex_destroy (&shared->child_mutex);
+  xpthread_mutex_destroy (&nonshared_mutex);
+  xmunmap (shared, sizeof (*shared));
+}
+
+static int
+do_test (void)
+{
+  for (int parent_bits = 0; parent_bits <= mutex_all_bits; ++parent_bits)
+    for (int child_bits = 0; child_bits <= mutex_all_bits; ++child_bits)
+      for (int nonshared_bits = 0; nonshared_bits <= mutex_all_bits;
+           ++nonshared_bits)
+        for (int lock_nonshared = 0; lock_nonshared < 2; ++lock_nonshared)
+          for (int lock_child = 0; lock_child < 2; ++lock_child)
+            {
+              if (test_verbose)
+                printf ("info: parent_bits=0x%x child_bits=0x%x"
+                        " nonshared_bits=0x%x%s%s\n",
+                        parent_bits, child_bits, nonshared_bits,
+                        lock_nonshared ? " lock_nonshared" : "",
+                        lock_child ? " lock_child" : "");
+              one_test (parent_bits, child_bits, nonshared_bits,
+                        lock_nonshared, lock_child);
+            }
+  return 0;
+}
+
+#include <support/test-driver.c>