path: root/libthreads/cthreads.h

/*
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 * HISTORY
 * $Log: cthreads.h,v $
 * Revision 1.14  1999/05/30 01:39:48  roland
 * 1999-05-29  Roland McGrath  <roland@baalperazim.frob.com>
 *
 * 	* cthreads.h (mutex_clear): Change again, to call mutex_init.
 *
 * Revision 1.13  1999/05/29 18:59:10  roland
 * 1999-05-29  Roland McGrath  <roland@baalperazim.frob.com>
 *
 * 	* cthreads.h (mutex_clear): Change from syntax error to no-op (with
 * 	warning avoidance).
 *
 * Revision 1.12  1996/05/04 10:06:31  roland
 * [lint] (NEVER): Spurious global variable removed.
 * [!lint] (NEVER): Useless macro removed.
 *
 * Revision 1.11  1996/01/24 18:37:59  roland
 * Use prototypes for functions of zero args.
 *
 * Revision 1.10  1995/09/13 19:50:07  mib
 * (CONDITION_INITIALIZER): Provide initial zero for IMPLICATIONS member.
 * (condition_init): Bother initializing NAME and IMPLICATIONS members.
 *
 * Revision 1.9  1995/08/30 15:51:41  mib
 * (condition_implies, condition_unimplies): New functions.
 * (struct condition): New member `implications'.
 * (cond_imp): New structure.
 * (cond_signal): Return int now.
 * (condition_broadcast): Always call cond_broadcast if this condition
 * has implications.
 * (condition_signal): Always call cond_signal if this condition has
 * implications.
 *
 * Revision 1.8  1995/08/30 15:10:23  mib
 * (hurd_condition_wait): Provide declaration.
 *
 * Revision 1.7  1995/07/18 17:15:51  mib
 * Reverse previous change.
 *
 * Revision 1.5  1995/04/04 21:06:16  roland
 * (mutex_lock, mutex_unlock): Use __ names for *_solid.
 *
 * Revision 1.4  1994/05/05  10:52:06  roland
 * entered into RCS
 *
 * Revision 2.12  92/05/22  18:38:36  jfriedl
 * 	From Mike Kupfer <kupfer@sprite.Berkeley.EDU>:
 * 	Add declaration for cthread_wire().
 * 	Merge in Jonathan Chew's changes for thread-local data.
 * 	Use MACRO_BEGIN and MACRO_END.
 *
 * Revision 1.8  91/03/25  14:14:49  jjc
 * 	For compatibility with cthread_data:
 * 		1) Added private_data field to cthread structure
 * 		   for use by POSIX thread specific data routines.
 * 		2) Conditionalized old data field used by cthread_data
 * 		   under CTHREAD_DATA for binary compatibility.
 * 		3) Changed macros, cthread_set_data and cthread_data,
 * 		   into routines which use the POSIX routines for
 * 		   source compatibility.
 * 		   Also, conditionalized under CTHREAD_DATA.
 * 	[91/03/18            jjc]
 * 	Added support for multiplexing the thread specific global
 * 	variable, cthread_data, using the POSIX threads interface
 * 	for thread private data.
 * 	[91/03/14            jjc]
 *
 * Revision 2.11  91/08/03  18:20:15  jsb
 * 	Removed the infamous line 122.
 * 	[91/08/01  22:40:24  jsb]
 *
 * Revision 2.10  91/07/31  18:35:42  dbg
 * 	Fix the standard-C conditional: it's __STDC__.
 *
 * 	Allow for macro-redefinition of cthread_sp, spin_try_lock,
 * 	spin_unlock (from machine/cthreads.h).
 * 	[91/07/30  17:34:28  dbg]
 *
 * Revision 2.9  91/05/14  17:56:42  mrt
 * 	Correcting copyright
 *
 * Revision 2.8  91/02/14  14:19:52  mrt
 * 	Added new Mach copyright
 * 	[91/02/13  12:41:15  mrt]
 *
 * Revision 2.7  90/11/05  14:37:12  rpd
 * 	Include machine/cthreads.h.  Added spin_lock_t.
 * 	[90/10/31            rwd]
 *
 * Revision 2.6  90/10/12  13:07:24  rpd
 * 	Channge to allow for positive stack growth.
 * 	[90/10/10            rwd]
 *
 * Revision 2.5  90/09/09  14:34:56  rpd
 * 	Remove mutex_special and debug_mutex.
 * 	[90/08/24            rwd]
 *
 * Revision 2.4  90/08/07  14:31:14  rpd
 * 	Removed RCS keyword nonsense.
 *
 * Revision 2.3  90/01/19  14:37:18  rwd
 * 	Add back pointer to cthread structure.
 * 	[90/01/03            rwd]
 * 	Change definition of cthread_init and change ur_cthread_self macro
 * 	to reflect movement of self pointer on stack.
 * 	[89/12/18  19:18:34  rwd]
 *
 * Revision 2.2  89/12/08  19:53:49  rwd
 * 	Change spin_try_lock to int.
 * 	[89/11/30            rwd]
 * 	Changed mutex macros to deal with special mutexs
 * 	[89/11/26            rwd]
 * 	Make mutex_{set,clear}_special routines instead of macros.
 * 	[89/11/25            rwd]
 * 	Added mutex_special to specify a need to context switch on this
 * 	mutex.
 * 	[89/11/21            rwd]
 *
 * 	Made mutex_lock a macro trying to grab the spin_lock first.
 * 	[89/11/13            rwd]
 * 	Removed conditionals.  Mutexes are more like conditions now.
 * 	Changed for limited kernel thread version.
 * 	[89/10/23            rwd]
 *
 * Revision 2.1  89/08/03  17:09:40  rwd
 * Created.
 *
 *
 * 28-Oct-88  Eric Cooper (ecc) at Carnegie Mellon University
 *	Implemented spin_lock() as test and test-and-set logic
 *	(using mutex_try_lock()) in sync.c.  Changed ((char *) 0)
 *	to 0, at Mike Jones's suggestion, and turned on ANSI-style
 *	declarations in either C++ or _STDC_.
 *
 * 29-Sep-88  Eric Cooper (ecc) at Carnegie Mellon University
 *	Changed NULL to ((char *) 0) to avoid dependency on <stdio.h>,
 *	at Alessandro Forin's suggestion.
 *
 * 08-Sep-88  Alessandro Forin (af) at Carnegie Mellon University
 *	Changed queue_t to cthread_queue_t and string_t to char *
 *	to avoid conflicts.
 *
 * 01-Apr-88  Eric Cooper (ecc) at Carnegie Mellon University
 *	Changed compound statement macros to use the
 *	do { ... } while (0) trick, so that they work
 *	in all statement contexts.
 *
 * 19-Feb-88  Eric Cooper (ecc) at Carnegie Mellon University
 *	Made spin_unlock() and mutex_unlock() into procedure calls
 *	rather than macros, so that even smart compilers can't reorder
 *	the clearing of the lock.  Suggested by Jeff Eppinger.
 *	Removed the now empty <machine>/cthreads.h.
 *
 * 01-Dec-87  Eric Cooper (ecc) at Carnegie Mellon University
 *	Changed cthread_self() to mask the current SP to find
 *	the self pointer stored at the base of the stack.
 *
 * 22-Jul-87  Eric Cooper (ecc) at Carnegie Mellon University
 *	Fixed bugs in mutex_set_name and condition_set_name
 *	due to bad choice of macro formal parameter name.
 *
 * 21-Jul-87  Eric Cooper (ecc) at Carnegie Mellon University
 *	Moved #include <machine/cthreads.h> to avoid referring
 *	to types before they are declared (required by C++).
 *
 *  9-Jul-87  Michael Jones (mbj) at Carnegie Mellon University
 *	Added conditional type declarations for C++.
 *	Added _cthread_init_routine and _cthread_exit_routine variables
 *	for automatic initialization and finalization by crt0.
 */
/*
 * 	File: 	cthreads.h
 *	Author: Eric Cooper, Carnegie Mellon University
 *	Date:	Jul, 1987
 *
 * 	Definitions for the C Threads package.
 *
 */


#ifndef	_CTHREADS_
#define	_CTHREADS_ 1

/* MIB XXX */
#define CTHREAD_DATA

#if 0
/* This is CMU's machine-dependent file.  In GNU all of the machine
   dependencies are dealt with in libc.  */
#include <machine/cthreads.h>
#else
#include <machine-sp.h>
#define cthread_sp()	((int) __thread_stack_pointer ())
#endif

#if	c_plusplus || __STDC__

#ifndef	C_ARG_DECLS
#define	C_ARG_DECLS(arglist)	arglist
#endif	/* not C_ARG_DECLS */

typedef void *any_t;

#else	/* not (c_plusplus || __STDC__) */

#ifndef	C_ARG_DECLS
#define	C_ARG_DECLS(arglist)	()
#endif	/* not C_ARG_DECLS */

typedef char *any_t;

#endif	/* not (c_plusplus || __STDC__) */

#include <mach/mach.h>
#include <mach/machine/vm_param.h>

#ifndef	TRUE
#define	TRUE	1
#define	FALSE	0
#endif	/* TRUE */


#undef	MACRO_BEGIN
#undef	MACRO_END
#define	MACRO_BEGIN	__extension__ ({
#define	MACRO_END	0; })


/*
 * C Threads package initialization.
 */

extern int cthread_init C_ARG_DECLS((void));
#if 0
/* This prototype is broken for GNU.  */
extern any_t calloc C_ARG_DECLS((unsigned n, unsigned size));
#else
#include <stdlib.h>
#endif

/*
 * Queues.
 */
typedef struct cthread_queue {
	struct cthread_queue_item *head;
	struct cthread_queue_item *tail;
} *cthread_queue_t;

typedef struct cthread_queue_item {
	struct cthread_queue_item *next;
} *cthread_queue_item_t;

#define	NO_QUEUE_ITEM	((cthread_queue_item_t) 0)

#define	QUEUE_INITIALIZER	{ NO_QUEUE_ITEM, NO_QUEUE_ITEM }

#define	cthread_queue_alloc()	((cthread_queue_t) calloc(1, sizeof(struct cthread_queue)))
#define	cthread_queue_init(q)	((q)->head = (q)->tail = 0)
#define	cthread_queue_free(q)	free((any_t) (q))

#define	cthread_queue_enq(q, x) \
	MACRO_BEGIN \
		(x)->next = 0; \
		if ((q)->tail == 0) \
			(q)->head = (cthread_queue_item_t) (x); \
		else \
			(q)->tail->next = (cthread_queue_item_t) (x); \
		(q)->tail = (cthread_queue_item_t) (x); \
	MACRO_END

#define	cthread_queue_preq(q, x) \
	MACRO_BEGIN \
		if ((q)->tail == 0) \
			(q)->tail = (cthread_queue_item_t) (x); \
		((cthread_queue_item_t) (x))->next = (q)->head; \
		(q)->head = (cthread_queue_item_t) (x); \
	MACRO_END

#define	cthread_queue_head(q, t)	((t) ((q)->head))

#define	cthread_queue_deq(q, t, x) \
	MACRO_BEGIN \
	if (((x) = (t) ((q)->head)) != 0 && \
	    ((q)->head = (cthread_queue_item_t) ((x)->next)) == 0) \
		(q)->tail = 0; \
	MACRO_END

#define	cthread_queue_map(q, t, f) \
	MACRO_BEGIN \
		register cthread_queue_item_t x, next; \
		for (x = (cthread_queue_item_t) ((q)->head); x != 0; x = next) { \
			next = x->next; \
			(*(f))((t) x); \
		} \
	MACRO_END

#if 1

/* In GNU, spin locks are implemented in libc.
   Just include its header file.  */
#include <spin-lock.h>

#else  /* Unused CMU code.  */

/*
 * Spin locks.
 */
extern void
spin_lock_solid C_ARG_DECLS((spin_lock_t *p));

#ifndef	spin_unlock
extern void
spin_unlock C_ARG_DECLS((spin_lock_t *p));
#endif

#ifndef	spin_try_lock
extern int
spin_try_lock C_ARG_DECLS((spin_lock_t *p));
#endif

#define spin_lock(p) ({if (!spin_try_lock(p)) spin_lock_solid(p);})

#endif /* End unused CMU code.  */

/*
 * Mutex objects.
 */
typedef struct mutex {
  /* The `held' member must be first in GNU.  The GNU C library relies on
     being able to cast a `struct mutex *' to a `spin_lock_t *' (which is
     kosher if it is the first member) and spin_try_lock that address to
     see if it gets the mutex.  */
	spin_lock_t held;
	spin_lock_t lock;
	char *name;
	struct cthread_queue queue;
} *mutex_t;

/* Rearranged accordingly for GNU: */
#define	MUTEX_INITIALIZER	{ SPIN_LOCK_INITIALIZER, SPIN_LOCK_INITIALIZER, 0, QUEUE_INITIALIZER }

#define	mutex_alloc()		((mutex_t) calloc(1, sizeof(struct mutex)))
#define	mutex_init(m) \
	MACRO_BEGIN \
	spin_lock_init(&(m)->lock); \
	cthread_queue_init(&(m)->queue); \
	spin_lock_init(&(m)->held); \
	MACRO_END
#define	mutex_set_name(m, x)	((m)->name = (x))
#define	mutex_name(m)		((m)->name != 0 ? (m)->name : "?")
#define	mutex_clear(m)		mutex_init(m)
#define	mutex_free(m)		free((any_t) (m))

extern void __mutex_lock_solid (void *mutex); /* blocking -- roland@gnu */
extern void __mutex_unlock_solid (void *mutex); /* roland@gnu */

#define mutex_try_lock(m) spin_try_lock(&(m)->held)
#define mutex_lock(m) \
	MACRO_BEGIN \
	if (!spin_try_lock(&(m)->held)) { \
		__mutex_lock_solid(m); \
	} \
	MACRO_END
#define mutex_unlock(m) \
	MACRO_BEGIN \
	if (spin_unlock(&(m)->held), \
	    cthread_queue_head(&(m)->queue, int) != 0) { \
		__mutex_unlock_solid(m); \
	} \
	MACRO_END

/*
 * Condition variables.
 */
typedef struct condition {
	spin_lock_t lock;
	struct cthread_queue queue;
	char *name;
	struct cond_imp *implications;
} *condition_t;

struct cond_imp
{
  struct condition *implicatand;
  struct cond_imp *next;
};

#define	CONDITION_INITIALIZER		{ SPIN_LOCK_INITIALIZER, QUEUE_INITIALIZER, 0, 0 }

#define	condition_alloc()		((condition_t) calloc(1, sizeof(struct condition)))
#define	condition_init(c) \
	MACRO_BEGIN \
	spin_lock_init(&(c)->lock); \
	cthread_queue_init(&(c)->queue); \
	(c)->name = 0; \
	(c)->implications = 0; \
	MACRO_END
#define	condition_set_name(c, x)	((c)->name = (x))
#define	condition_name(c)		((c)->name != 0 ? (c)->name : "?")
#define	condition_clear(c) \
	MACRO_BEGIN \
	condition_broadcast(c); \
	spin_lock(&(c)->lock); \
	MACRO_END
#define	condition_free(c) \
	MACRO_BEGIN \
	condition_clear(c); \
	free((any_t) (c)); \
	MACRO_END

#define	condition_signal(c) \
	MACRO_BEGIN \
	if ((c)->queue.head || (c)->implications) { \
		cond_signal(c); \
	} \
	MACRO_END

#define	condition_broadcast(c) \
	MACRO_BEGIN \
	if ((c)->queue.head || (c)->implications) { \
		cond_broadcast(c); \
	} \
	MACRO_END

extern int
cond_signal C_ARG_DECLS((condition_t c));

extern void
cond_broadcast C_ARG_DECLS((condition_t c));

extern void
condition_wait C_ARG_DECLS((condition_t c, mutex_t m));

extern int
hurd_condition_wait C_ARG_DECLS((condition_t c, mutex_t m));

extern void
condition_implies C_ARG_DECLS((condition_t implicator, condition_t implicatand));

extern void
condition_unimplies C_ARG_DECLS((condition_t implicator, condition_t implicatand));

/*
 * Threads.
 */

typedef any_t (*cthread_fn_t) C_ARG_DECLS((any_t arg));

#include <setjmp.h>

typedef struct cthread {
	struct cthread *next;
	struct mutex lock;
	struct condition done;
	int state;
	jmp_buf catch;
	cthread_fn_t func;
	any_t arg;
	any_t result;
	char *name;
#ifdef	CTHREAD_DATA
	any_t data;
#endif	CTHREAD_DATA
	any_t private_data;
	struct ur_cthread *ur;
} *cthread_t;

#define	NO_CTHREAD	((cthread_t) 0)

extern cthread_t
cthread_fork C_ARG_DECLS((cthread_fn_t func, any_t arg));

extern void
cthread_detach C_ARG_DECLS((cthread_t t));

extern any_t
cthread_join C_ARG_DECLS((cthread_t t));

extern void
cthread_yield C_ARG_DECLS((void));

extern void
cthread_exit C_ARG_DECLS((any_t result));

/*
 * This structure must agree with struct cproc in cthread_internals.h
 */
typedef struct ur_cthread {
	struct ur_cthread *next;
	cthread_t incarnation;
} *ur_cthread_t;

#ifndef	cthread_sp
extern int
cthread_sp C_ARG_DECLS((void));
#endif

extern int cthread_stack_mask;

#ifdef	STACK_GROWTH_UP
#define	ur_cthread_ptr(sp) \
	(* (ur_cthread_t *) ((sp) & cthread_stack_mask))
#else	STACK_GROWTH_UP
#define	ur_cthread_ptr(sp) \
	(* (ur_cthread_t *) ( ((sp) | cthread_stack_mask) + 1 \
			      - sizeof(ur_cthread_t *)) )
#endif	STACK_GROWTH_UP

#define	ur_cthread_self()	(ur_cthread_ptr(cthread_sp()))

#define	cthread_assoc(id, t)	((((ur_cthread_t) (id))->incarnation = (t)), \
				((t) ? ((t)->ur = (ur_cthread_t)(id)) : 0))
#define	cthread_self()		(ur_cthread_self()->incarnation)

extern void
cthread_set_name C_ARG_DECLS((cthread_t t, char *name));

extern char *
cthread_name C_ARG_DECLS((cthread_t t));

extern int
cthread_count C_ARG_DECLS((void));

extern void
cthread_set_limit C_ARG_DECLS((int n));

extern int
cthread_limit C_ARG_DECLS((void));

extern void
cthread_wire C_ARG_DECLS((void));

#ifdef	CTHREAD_DATA
/*
 * Set or get thread specific "global" variable
 *
 * The thread given must be the calling thread (ie. thread_self).
 * XXX This is for compatibility with the old cthread_data. XXX
 */
extern int
cthread_set_data C_ARG_DECLS((cthread_t t, any_t x));

extern any_t
cthread_data C_ARG_DECLS((cthread_t t));
#endif	CTHREAD_DATA

/*
 * Support for POSIX thread specific data
 *
 * Multiplexes a thread specific "global" variable
 * into many thread specific "global" variables.
 */
#define CTHREAD_DATA_VALUE_NULL		(any_t)0
#define	CTHREAD_KEY_INVALID		(cthread_key_t)-1

typedef int	cthread_key_t;

/*
 * Create key to private data visible to all threads in task.
 * Different threads may use same key, but the values bound to the key are
 * maintained on a thread specific basis.
 */
extern int
cthread_keycreate C_ARG_DECLS((cthread_key_t *key));

/*
 * Get value currently bound to key for calling thread
 */
extern int
cthread_getspecific C_ARG_DECLS((cthread_key_t key, any_t *value));

/*
 * Bind value to given key for calling thread
 */
extern int
cthread_setspecific C_ARG_DECLS((cthread_key_t key, any_t value));

/*
 * Debugging support.
 */
#ifdef	DEBUG

#ifndef	ASSERT
/*
 * Assertion macro, similar to <assert.h>
 */
#include <stdio.h>
#define	ASSERT(p) \
	MACRO_BEGIN \
	if (!(p)) { \
		fprintf(stderr, \
			"File %s, line %d: assertion p failed.\n", \
			__FILE__, __LINE__); \
		abort(); \
	} \
	MACRO_END

#endif	ASSERT

#define	SHOULDNT_HAPPEN	0

extern int cthread_debug;

#else	DEBUG

#ifndef	ASSERT
#define	ASSERT(p)
#endif	ASSERT

#endif	DEBUG

#endif	_CTHREADS_