Remove _THREAD_SAFE and make libc thread-safe by default by

adding (weak definitions to) stubs for some of the pthread
functions.  If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
	__sys_foo - actual system call
	_foo - weak definition to __sys_foo
	foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo.  In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde).  All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes.  <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h  namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE.  We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by:	-arch

1 files changed, 131 insertions, 0 deletions

diff --git a/lib/libc/gen/_pthread_stubs.c b/lib/libc/gen/_pthread_stubs.c
new file mode 100644
index 0000000..87b0ad2
--- /dev/null
+++ b/lib/libc/gen/_pthread_stubs.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#include <pthread.h>
+
+/*
+ * Weak symbols: All libc internal usage of these functions should
+ * use the weak symbol versions (_pthread_XXX).  If libpthread is
+ * linked, it will override these functions with (non-weak) routines.
+ * The _pthread_XXX functions are provided solely for internal libc
+ * usage to avoid unwanted cancellation points and to differentiate
+ * between application locks and libc locks (threads holding the
+ * latter can't be allowed to exit/terminate).
+ */
+#pragma weak	_pthread_getspecific=_pthread_getspecific_stub
+#pragma weak	_pthread_key_create=_pthread_key_create_stub
+#pragma weak	_pthread_key_delete=_pthread_key_delete_stub
+#pragma weak	_pthread_mutex_destroy=_pthread_mutex_destroy_stub
+#pragma weak	_pthread_mutex_init=_pthread_mutex_init_stub
+#pragma weak	_pthread_mutex_lock=_pthread_mutex_lock_stub
+#pragma weak	_pthread_mutex_trylock=_pthread_mutex_trylock_stub
+#pragma weak	_pthread_mutex_unlock=_pthread_mutex_unlock_stub
+#pragma weak	_pthread_mutexattr_init=_pthread_mutexattr_init_stub
+#pragma weak	_pthread_mutexattr_destroy=_pthread_mutexattr_destroy_stub
+#pragma weak	_pthread_mutexattr_settype=_pthread_mutexattr_settype_stub
+#pragma weak	_pthread_once=_pthread_once_stub
+#pragma weak	_pthread_setspecific=_pthread_setspecific_stub
+
+
+void *
+_pthread_getspecific_stub(pthread_key_t key)
+{
+	return (NULL);
+}
+
+int
+_pthread_key_create_stub(pthread_key_t *key, void (*destructor) (void *))
+{
+	return (0);
+}
+
+int
+_pthread_key_delete_stub(pthread_key_t key)
+{
+	return (0);
+}
+
+int
+_pthread_mutex_destroy_stub(pthread_mutex_t *mattr)
+{
+	return (0);
+}
+
+int
+_pthread_mutex_init_stub(pthread_mutex_t *mutex, const pthread_mutexattr_t *mattr)
+{
+	return (0);
+}
+
+int
+_pthread_mutex_lock_stub(pthread_mutex_t *mutex)
+{
+	return (0);
+}
+
+int
+_pthread_mutex_trylock_stub(pthread_mutex_t *mutex)
+{
+	return (0);
+}
+
+int
+_pthread_mutex_unlock_stub(pthread_mutex_t *mutex)
+{
+	return (0);
+}
+
+int
+_pthread_mutexattr_init_stub(pthread_mutexattr_t *mattr)
+{
+	return (0);
+}
+
+int
+_pthread_mutexattr_destroy_stub(pthread_mutexattr_t *mattr)
+{
+	return (0);
+}
+
+int
+_pthread_mutexattr_settype_stub(pthread_mutexattr_t *mattr, int type)
+{
+	return (0);
+}
+
+int
+_pthread_once_stub(pthread_once_t *once_control, void (*init_routine) (void))
+{
+	return (0);
+}
+
+int
+_pthread_setspecific_stub(pthread_key_t key, const void *value)
+{
+	return (0);
+}