nptl: Add tst-robust-fork

2017-01-13  Florian Weimer  <fweimer@redhat.com>

	* nptl/Makefile (tests): Add tst-robust-fork.
	* nptl/tst-robust-fork.c: New file.
	* support/Makefile (libsupport-routines): Add xmmap, xmunmap,
	xpthread_mutex_consistent, xpthread_mutex_destroy,
	xpthread_mutex_init, xpthread_mutexattr_destroy,
	xpthread_mutexattr_init, xpthread_mutexattr_setprotocol,
	xpthread_mutexattr_setpshared, xpthread_mutexattr_setrobust.
	* support/xmmap.c: New file.
	* support/xmunmap.c: Likewise.
	* support/xpthread_mutex_consistent.c: Likewise.
	* support/xpthread_mutex_destroy.c: Likewise.
	* support/xpthread_mutex_init.c: Likewise.
	* support/xpthread_mutexattr_destroy.c: Likewise.
	* support/xpthread_mutexattr_init.c: Likewise.
	* support/xpthread_mutexattr_setprotocol.c: Likewise.
	* support/xpthread_mutexattr_setpshared.c: Likewise.
	* support/xpthread_mutexattr_setrobust.c: Likewise.
	* support/xthread.h (xpthread_mutexattr_destroy)
	(xpthread_mutexattr_init, xpthread_mutexattr_setprotocol)
	(xpthread_mutexattr_setpshared, xpthread_mutexattr_setrobust)
	(xpthread_mutex_init, xpthread_mutex_destroy)
	(xpthread_mutex_consistent): Declare.
	* support/xunistd.h (xmmap, xmunmap): Likewise.

diff --git a/nptl/Makefile b/nptl/Makefile
index 9d5738f..19d7892 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 0000000..84655c9
--- /dev/null
+++ b/nptl/tst-robust-fork.c
@@ -0,0 +1,169 @@
+/* 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/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,
+
+    /* All bits combined.  */
+    mutex_all_bits = 7,
+  };
+
+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);
+  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)
+        pthread_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);
+  }
+
+  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.  */
+        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)
+            {
+              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>
diff --git a/support/Makefile b/support/Makefile
index 7114855..7e0b975 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -61,6 +61,8 @@ libsupport-routines = \
   xlisten \
   xmalloc \
   xmemstream \
+  xmmap \
+  xmunmap \
   xpoll \
   xpthread_barrier_destroy \
   xpthread_barrier_init \
@@ -71,8 +73,16 @@ libsupport-routines = \
   xpthread_create \
   xpthread_detach \
   xpthread_join \
+  xpthread_mutex_consistent \
+  xpthread_mutex_destroy \
+  xpthread_mutex_init \
   xpthread_mutex_lock \
   xpthread_mutex_unlock \
+  xpthread_mutexattr_destroy \
+  xpthread_mutexattr_init \
+  xpthread_mutexattr_setprotocol \
+  xpthread_mutexattr_setpshared \
+  xpthread_mutexattr_setrobust \
   xpthread_once \
   xpthread_sigmask \
   xpthread_spin_lock \
diff --git a/support/xmmap.c b/support/xmmap.c
new file mode 100644
index 0000000..435b1eb
--- /dev/null
+++ b/support/xmmap.c
@@ -0,0 +1,31 @@
+/* mmap with error checking.
+   Copyright (C) 2016-2017 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 <support/check.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+
+void *
+xmmap (void *addr, size_t length, int prot, int flags, int fd)
+{
+  void *result = mmap (addr, length, prot, flags, fd, 0);
+  if (result == MAP_FAILED)
+    FAIL_EXIT1 ("mmap of %zu bytes, prot=0x%x, flags=0x%x: %m",
+                length, prot, flags);
+  return result;
+}
diff --git a/support/xmunmap.c b/support/xmunmap.c
new file mode 100644
index 0000000..6ef5a4a
--- /dev/null
+++ b/support/xmunmap.c
@@ -0,0 +1,28 @@
+/* munmap with error checking.
+   Copyright (C) 2016-2017 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 <support/check.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+
+void
+xmunmap (void *addr, size_t length)
+{
+  if (munmap (addr, length) != 0)
+    FAIL_EXIT1 ("munmap of %zu bytes: %m", length);
+}
diff --git a/support/xpthread_mutex_consistent.c b/support/xpthread_mutex_consistent.c
new file mode 100644
index 0000000..52364be
--- /dev/null
+++ b/support/xpthread_mutex_consistent.c
@@ -0,0 +1,26 @@
+/* pthread_mutex_consistent with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutex_consistent (pthread_mutex_t *mutex)
+{
+  xpthread_check_return ("pthread_mutex_consistent",
+                         pthread_mutex_consistent (mutex));
+}
diff --git a/support/xpthread_mutex_destroy.c b/support/xpthread_mutex_destroy.c
new file mode 100644
index 0000000..f11f8f0
--- /dev/null
+++ b/support/xpthread_mutex_destroy.c
@@ -0,0 +1,26 @@
+/* pthread_mutex_destroy with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutex_destroy (pthread_mutex_t *mutex)
+{
+  xpthread_check_return ("pthread_mutex_destroy",
+                         pthread_mutex_destroy (mutex));
+}
diff --git a/support/xpthread_mutex_init.c b/support/xpthread_mutex_init.c
new file mode 100644
index 0000000..2d16d1b
--- /dev/null
+++ b/support/xpthread_mutex_init.c
@@ -0,0 +1,26 @@
+/* pthread_mutex_init with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutex_init (pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
+{
+  xpthread_check_return ("pthread_mutex_init",
+                         pthread_mutex_init (mutex, attr));
+}
diff --git a/support/xpthread_mutexattr_destroy.c b/support/xpthread_mutexattr_destroy.c
new file mode 100644
index 0000000..c699e32
--- /dev/null
+++ b/support/xpthread_mutexattr_destroy.c
@@ -0,0 +1,26 @@
+/* pthread_mutexattr_destroy with error checking.
+   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 <support/xthread.h>
+
+void
+xpthread_mutexattr_destroy (pthread_mutexattr_t *attr)
+{
+  xpthread_check_return ("pthread_mutexattr_destroy",
+                         pthread_mutexattr_destroy (attr));
+}
diff --git a/support/xpthread_mutexattr_init.c b/support/xpthread_mutexattr_init.c
new file mode 100644
index 0000000..fa93fab
--- /dev/null
+++ b/support/xpthread_mutexattr_init.c
@@ -0,0 +1,25 @@
+/* pthread_mutexattr_init with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutexattr_init (pthread_mutexattr_t *attr)
+{
+  xpthread_check_return ("pthread_mutexattr_init", pthread_mutexattr_init (attr));
+}
diff --git a/support/xpthread_mutexattr_setprotocol.c b/support/xpthread_mutexattr_setprotocol.c
new file mode 100644
index 0000000..353f75e
--- /dev/null
+++ b/support/xpthread_mutexattr_setprotocol.c
@@ -0,0 +1,26 @@
+/* pthread_mutexattr_setprotocol with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutexattr_setprotocol (pthread_mutexattr_t *attr, int flag)
+{
+  xpthread_check_return ("pthread_mutexattr_setprotocol",
+                         pthread_mutexattr_setprotocol (attr, flag));
+}
diff --git a/support/xpthread_mutexattr_setpshared.c b/support/xpthread_mutexattr_setpshared.c
new file mode 100644
index 0000000..242da1a
--- /dev/null
+++ b/support/xpthread_mutexattr_setpshared.c
@@ -0,0 +1,26 @@
+/* pthread_mutexattr_setpshared with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutexattr_setpshared (pthread_mutexattr_t *attr, int flag)
+{
+  xpthread_check_return ("pthread_mutexattr_setpshared",
+                         pthread_mutexattr_setpshared (attr, flag));
+}
diff --git a/support/xpthread_mutexattr_setrobust.c b/support/xpthread_mutexattr_setrobust.c
new file mode 100644
index 0000000..d7d6fa8
--- /dev/null
+++ b/support/xpthread_mutexattr_setrobust.c
@@ -0,0 +1,26 @@
+/* pthread_mutexattr_setrobust with error checking.
+   Copyright (C) 2016-2017 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 <support/xthread.h>
+
+void
+xpthread_mutexattr_setrobust (pthread_mutexattr_t *attr, int flag)
+{
+  xpthread_check_return ("pthread_mutexattr_setrobust",
+                         pthread_mutexattr_setrobust (attr, flag));
+}
diff --git a/support/xthread.h b/support/xthread.h
index e5c896b..a61272a 100644
--- a/support/xthread.h
+++ b/support/xthread.h
@@ -41,8 +41,16 @@ void xpthread_check_return (const char *function, int value);
 void xpthread_barrier_init (pthread_barrier_t *barrier,
                             pthread_barrierattr_t *attr, unsigned int count);
 void xpthread_barrier_destroy (pthread_barrier_t *barrier);
+void xpthread_mutexattr_destroy (pthread_mutexattr_t *);
+void xpthread_mutexattr_init (pthread_mutexattr_t *);
+void xpthread_mutexattr_setprotocol (pthread_mutexattr_t *, int);
+void xpthread_mutexattr_setpshared (pthread_mutexattr_t *, int);
+void xpthread_mutexattr_setrobust (pthread_mutexattr_t *, int);
+void xpthread_mutex_init (pthread_mutex_t *, const pthread_mutexattr_t *);
+void xpthread_mutex_destroy (pthread_mutex_t *);
 void xpthread_mutex_lock (pthread_mutex_t *mutex);
 void xpthread_mutex_unlock (pthread_mutex_t *mutex);
+void xpthread_mutex_consistent (pthread_mutex_t *);
 void xpthread_spin_lock (pthread_spinlock_t *lock);
 void xpthread_spin_unlock (pthread_spinlock_t *lock);
 void xpthread_cond_wait (pthread_cond_t * cond, pthread_mutex_t * mutex);
diff --git a/support/xunistd.h b/support/xunistd.h
index 11fbc9f..a83b1f4 100644
--- a/support/xunistd.h
+++ b/support/xunistd.h
@@ -33,6 +33,11 @@ pid_t xwaitpid (pid_t, int *status, int flags);
 /* Write the buffer.  Retry on short writes.  */
 void xwrite (int, const void *, size_t);
 
+/* Invoke mmap with a zero file offset.  */
+void *xmmap (void *addr, size_t length, int prot, int flags, int fd);
+
+void xmunmap (void *addr, size_t length);
+
 __END_DECLS
 
 #endif /* SUPPORT_XUNISTD_H */
