Add thread-safety to libc, so that libc_r will build (on i386 at least).

All POSIX libc api now there (to P1003.1c/D10)
  (more md stuff is needed for other libc/arch/*)
  (setlogin is no longer a special syscall)
Add -pthread option to gcc (that makes it use -lc_r and -D_POSIX_THREADS).
Doc some re-entrant routines
Add libc_r to intro(3)
dig() uses some libc srcs and an extra -I was needed there.
Add more md stuff to libc_r.
Update includes for the pthreads api
Update libc_r TODO

2 files changed, 248 insertions, 0 deletions

diff --git a/lib/libc/include/spinlock.h b/lib/libc/include/spinlock.h
new file mode 100644
index 00000000000..e4871f9aede
--- /dev/null
+++ b/lib/libc/include/spinlock.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by John Birrell.
+ * 4. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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.
+ *
+ * $Id: spinlock.h,v 1.1 1998/11/20 11:18:41 d Exp $
+ * $OpenBSD: spinlock.h,v 1.1 1998/11/20 11:18:41 d Exp $
+ *
+ * Lock definitions used in both libc and libpthread.
+ *
+ */
+
+#ifndef _SPINLOCK_H_
+#define _SPINLOCK_H_
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+/*
+ * Lock structure with room for debugging information.
+ */
+typedef struct {
+	volatile register_t	access_lock;
+	volatile long	lock_owner;
+	volatile const char * fname;
+	volatile int	lineno;
+} spinlock_t;
+
+#define	_SPINLOCK_INITIALIZER	{ 0, 0, 0, 0 }
+
+#define _SPINUNLOCK(_lck)	(_lck)->access_lock = 0
+#ifdef	_LOCK_DEBUG
+#define	_SPINLOCK(_lck)		_spinlock_debug(_lck, __FILE__, __LINE__)
+#else
+#define	_SPINLOCK(_lck)		_spinlock(_lck)
+#endif
+
+/*
+ * Thread function prototype definitions:
+ */
+__BEGIN_DECLS
+register_t	_atomic_lock __P((volatile register_t *));
+register_t	_thread_slow_atomic_lock __P((volatile register_t *));
+void	_spinlock __P((spinlock_t *));
+void	_spinlock_debug __P((spinlock_t *, const char *, int));
+__END_DECLS
+
+#endif /* _SPINLOCK_H_ */
diff --git a/lib/libc/include/thread_private.h b/lib/libc/include/thread_private.h
new file mode 100644
index 00000000000..a7f77490780
--- /dev/null
+++ b/lib/libc/include/thread_private.h
@@ -0,0 +1,175 @@
+/*
+ *
+ * Support for thread-safety in libc and libc_r common code using macros 
+ * to declare thread-safe data structures.
+ *
+ * $OpenBSD: thread_private.h,v 1.1 1998/11/20 11:18:41 d Exp $
+ */
+
+#ifndef _THREAD_PRIVATE_H_
+#define _THREAD_PRIVATE_H_
+
+/*
+ * Parts of this file are
+ * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
+ * All rights reserved.
+ *
+ * $Id: thread_private.h,v 1.1 1998/11/20 11:18:41 d Exp $
+ * $OpenBSD: thread_private.h,v 1.1 1998/11/20 11:18:41 d Exp $
+ */
+
+/*
+ * This global flag is non-zero when a process has created one
+ * or more threads. It is used to avoid calling locking functions
+ * when they are not required. In libc, this is always assumed
+ * to be zero.
+ */
+
+extern volatile int	__isthreaded;
+
+#ifdef _THREAD_SAFE
+
+#include <pthread.h>
+#include "pthread_private.h"
+
+#ifdef __STDC__
+#define __THREAD_MUTEXP_NAME(name)	_thread_mutexp_inst__ ## name
+#define __THREAD_MUTEX_NAME(name)	_thread_mutex_inst__ ## name
+#define __THREAD_KEY_NAME(name)		_thread_key_inst__ ## name
+#else
+#define __THREAD_MUTEXP_NAME(name)	_thread_mutexp_inst__/**/name
+#define __THREAD_MUTEX_NAME(name)	_thread_mutex_inst__/**/name
+#define __THREAD_KEY_NAME(name)		_thread_key_inst__/**/name
+#endif
+
+/*
+ * Mutex declare, lock and unlock macros.
+ */
+
+#define _THREAD_PRIVATE_MUTEX(name)					\
+	static struct pthread_mutex __THREAD_MUTEXP_NAME(name) =	\
+		PTHREAD_MUTEX_STATIC_INITIALIZER;			\
+	static pthread_mutex_t __THREAD_MUTEX_NAME(name) = 		\
+		&__THREAD_MUTEXP_NAME(name);
+		
+#define _THREAD_PRIVATE_MUTEX_LOCK(name) 				\
+	pthread_mutex_lock(&__THREAD_MUTEX_NAME(name))
+		
+#define _THREAD_PRIVATE_MUTEX_UNLOCK(name) 				\
+	pthread_mutex_unlock(&__THREAD_MUTEX_NAME(name))
+
+/*
+ * These macros help in making persistent storage thread-specific.
+ * Libc makes extensive use of private static data structures
+ * that hold state across function invocation, and these macros
+ * are no-ops when _THREAD_SAFE is not defined. 
+ * In a thread-safe library, the static variables are used only for
+ * initialising the per-thread instances of the state variables.
+ */
+
+/*
+ * a mutexed data structure used to hold the persistent state's key
+ */
+struct _thread_private_key_struct {
+	struct pthread_mutex	lockd;
+	pthread_mutex_t		lock;
+	int			init;
+	pthread_key_t		key;
+};
+
+/*
+ * Declaration of a per-thread state key.
+ */
+#define _THREAD_PRIVATE_KEY(name)					\
+	static volatile struct _thread_private_key_struct		\
+	__THREAD_KEY_NAME(name) = {					\
+		PTHREAD_MUTEX_STATIC_INITIALIZER, 			\
+		&__THREAD_KEY_NAME(name).lockd,				\
+		0							\
+	};
+
+/*
+ * Initialisation of storage space for a per-thread state variable.
+ * A pointer to a per-thread *copy* of the _initv parameter is returned.
+ * It calls malloc the first time and the space is automatically free'd
+ * when the thread dies. If you need something a bit more complicated
+ * than free() you will need to roll-your-own.
+ */
+#define _THREAD_PRIVATE(keyname, _initv, _errv) 			\
+	({								\
+		struct _thread_private_key_struct * __k = 		\
+			&__THREAD_KEY_NAME(keyname);			\
+		void* __p;						\
+		extern void free __P((void*));				\
+		extern void* malloc __P((size_t));			\
+									\
+		if (!__isthreaded) {					\
+			/* non-threaded behaviour */			\
+			__p = &(_initv);				\
+			goto _ok;					\
+		}							\
+									\
+		/* create key for first thread */			\
+		pthread_mutex_lock(&__k->lock);				\
+		if (__k->init == 0) {					\
+			if (pthread_key_create(&__k->key, free)) {	\
+				pthread_mutex_unlock(&__k->lock);	\
+				goto _err;				\
+			}						\
+			__k->init = 1;					\
+		}							\
+		pthread_mutex_unlock(&__k->lock);			\
+									\
+		if ((__p = pthread_getspecific(__k->key)) == NULL) {	\
+			/* alloc space on 1st call in this thread */	\
+			if ((__p = malloc(sizeof(_initv))) == NULL) 	\
+				goto _err;				\
+				if (pthread_setspecific(__k->key, __p) != 0) { \
+					free(__p);			\
+					goto _err;			\
+				}					\
+			/* initialise with _initv */			\
+		memcpy(__p, &_initv, sizeof(_initv));			\
+		}							\
+		goto _ok;						\
+	_err:								\
+		__p = (_errv);						\
+	_ok:								\
+		__p;							\
+	})
+
+#else
+
+
+/*
+ * do-nothing macros for single-threaded case
+ */
+#define _FD_LOCK(f,o,p)				(0)
+#define _FD_UNLOCK(f,o)				/* nothing */
+#define _THREAD_PRIVATE_KEY(_key)		/* nothing */
+#define _THREAD_PRIVATE(keyname, _initv, _errv)	(&(_initv))
+#define _THREAD_PRIVATE_MUTEX(_name)		/* nothing */
+#define _THREAD_PRIVATE_MUTEX_LOCK(_name)	/* nothing */
+#define _THREAD_PRIVATE_MUTEX_UNLOCK(_name)	/* nothing */
+
+#endif
+
+/*
+ * File lock contention is difficult to diagnose without knowing
+ * where locks were set. Allow a debug library to be built which
+ * records the source file and line number of each lock call.
+ */
+#ifdef	_FLOCK_DEBUG
+#define _FLOCKFILE(x)	_flockfile_debug(x, __FILE__, __LINE__)
+#else
+#define _FLOCKFILE(x)	flockfile(x)
+#endif
+
+/*
+ * Macros for locking and unlocking FILEs. These test if the
+ * process is threaded to avoid locking when not required.
+ */
+#define	FLOCKFILE(fp)		if (__isthreaded) _FLOCKFILE(fp)
+#define	FUNLOCKFILE(fp)		if (__isthreaded) funlockfile(fp)
+
+#endif _THREAD_PRIVATE_H_