diff --git a/libc/upstream-freebsd/freebsd-compat.h b/libc/upstream-freebsd/freebsd-compat.h
index 8030eea..74dc679 100644
--- a/libc/upstream-freebsd/freebsd-compat.h
+++ b/libc/upstream-freebsd/freebsd-compat.h
@@ -20,11 +20,31 @@
 #define __USE_BSD
 #define REPLACE_GETOPT
 
+/*
+ * FreeBSD's libc has three symbols for every symbol:
+ *
+ *     __f will be the actual implementation.
+ *     _f will be a weak reference to __f (used for calls to f from within the library).
+ *     f will be a weak reference to __f (used for calls to f from outside the library).
+ *
+ * We collapse this into just the one symbol, f.
+ */
+
+/* Prevent weak reference generation. */
+#define __weak_reference(sym,alias)
+
+/* Ensure that the implementation itself gets the underscore-free name. */
+#define __sleep sleep
+#define __usleep usleep
+
+/* Redirect internal C library calls to the public function. */
 #define _close close
 #define _fcntl fcntl
 #define _fstat fstat
+#define _nanosleep nanosleep
 #define _open open
 
-#define _sseek __sseek /* Needed as long as we have a mix of OpenBSD and FreeBSD stdio. */
+/* This one is only needed as long as we have a mix of OpenBSD and FreeBSD stdio. */
+#define _sseek __sseek
 
 #endif
diff --git a/libc/upstream-freebsd/lib/libc/gen/sleep.c b/libc/upstream-freebsd/lib/libc/gen/sleep.c
new file mode 100644
index 0000000..b807c2d
--- /dev/null
+++ b/libc/upstream-freebsd/lib/libc/gen/sleep.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)sleep.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <errno.h>
+#include <limits.h>
+#include <time.h>
+#include <unistd.h>
+#include "un-namespace.h"
+
+unsigned int
+__sleep(unsigned int seconds)
+{
+	struct timespec time_to_sleep;
+	struct timespec time_remaining;
+
+	/*
+	 * Avoid overflow when `seconds' is huge.  This assumes that
+	 * the maximum value for a time_t is >= INT_MAX.
+	 */
+	if (seconds > INT_MAX)
+		return (seconds - INT_MAX + __sleep(INT_MAX));
+
+	time_to_sleep.tv_sec = seconds;
+	time_to_sleep.tv_nsec = 0;
+	if (_nanosleep(&time_to_sleep, &time_remaining) != -1)
+		return (0);
+	if (errno != EINTR)
+		return (seconds);		/* best guess */
+	return (time_remaining.tv_sec +
+		(time_remaining.tv_nsec != 0)); /* round up */
+}
+
+__weak_reference(__sleep, sleep);
+__weak_reference(__sleep, _sleep);
diff --git a/libc/upstream-freebsd/lib/libc/gen/usleep.c b/libc/upstream-freebsd/lib/libc/gen/usleep.c
new file mode 100644
index 0000000..7d6559b
--- /dev/null
+++ b/libc/upstream-freebsd/lib/libc/gen/usleep.c
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)usleep.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <time.h>
+#include <unistd.h>
+#include "un-namespace.h"
+
+int
+__usleep(useconds_t useconds)
+{
+	struct timespec time_to_sleep;
+
+	time_to_sleep.tv_nsec = (useconds % 1000000) * 1000;
+	time_to_sleep.tv_sec = useconds / 1000000;
+	return (_nanosleep(&time_to_sleep, NULL));
+}
+
+__weak_reference(__usleep, usleep);
+__weak_reference(__usleep, _usleep);