cpython/Python/thread.c

/***********************************************************
Copyright 1991, 1992, 1993 by Stichting Mathematisch Centrum,
Amsterdam, The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the names of Stichting Mathematisch
Centrum or CWI not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior permission.

STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

#include "thread.h"

#ifdef DEBUG
static int thread_debug = 0;
#define dprintf(args)	(thread_debug && printf args)
#else
#define dprintf(args)
#endif

#ifdef __sgi
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/prctl.h>
#include <ulocks.h>
#include <errno.h>

#define HDR_SIZE	2680	/* sizeof(ushdr_t) */
#define MAXPROC		100	/* max # of threads that can be started */

/*static*/ usptr_t *shared_arena;
static ulock_t count_lock;	/* protection for some variables */
static ulock_t wait_lock;	/* lock used to wait for other threads */
static int waiting_for_threads;	/* protected by count_lock */
static int nthreads;		/* protected by count_lock */
static int exit_status;
static int do_exit;		/* indicates that the program is to exit */
static int exiting;		/* we're already exiting (for maybe_exit) */
static pid_t my_pid;		/* PID of main thread */
static pid_t pidlist[MAXPROC];	/* PIDs of other threads */
static int maxpidindex;		/* # of PIDs in pidlist */
#endif
#ifdef sun
#include <lwp/lwp.h>
#include <lwp/stackdep.h>

#define STACKSIZE	1000	/* stacksize for a thread */
#define NSTACKS		2	/* # stacks to be put in cache initialy */

struct lock {
	int lock_locked;
	cv_t lock_condvar;
	mon_t lock_monitor;
};
#endif
#ifdef C_THREADS
#include <cthreads.h>
#endif

#ifdef __STDC__
#define _P(args)		args
#define _P0()			(void)
#define _P1(v,t)		(t)
#define _P2(v1,t1,v2,t2)	(t1,t2)
#else
#define _P(args)		()
#define _P0()			()
#define _P1(v,t)		(v) t;
#define _P2(v1,t1,v2,t2)	(v1,v2) t1; t2;
#endif

static int initialized;

#ifdef __sgi
/*
 * This routine is called as a signal handler when another thread
 * exits.  When that happens, we must see whether we have to exit as
 * well (because of an exit_prog()) or whether we should continue on.
 */
static void exit_sig _P0()
{
	dprintf(("exit_sig called\n"));
	if (exiting && getpid() == my_pid) {
		dprintf(("already exiting\n"));
		return;
	}
	if (do_exit) {
		dprintf(("exiting in exit_sig\n"));
		exit_thread();
	}
}

/*
 * This routine is called when a process calls exit().  If that wasn't
 * done from the library, we do as if an exit_prog() was intended.
 */
static void maybe_exit _P0()
{
	dprintf(("maybe_exit called\n"));
	if (exiting) {
		dprintf(("already exiting\n"));
		return;
	}
	exit_prog(0);
}
#endif

/*
 * Initialization.
 */
void init_thread _P0()
{
#ifdef __sgi
	struct sigaction s;
#ifdef USE_DL
	long addr, size;
#endif
#endif

#ifdef DEBUG
	thread_debug = getenv("THREADDEBUG") != 0;
#endif
	if (initialized)
		return;
	initialized = 1;
	dprintf(("init_thread called\n"));

#ifdef __sgi
#ifdef USE_DL
	if ((size = usconfig(CONF_INITSIZE, 64*1024)) < 0)
		perror("usconfig - CONF_INITSIZE (check)");
	if (usconfig(CONF_INITSIZE, size) < 0)
		perror("usconfig - CONF_INITSIZE (reset)");
	addr = (long) dl_getrange(size + HDR_SIZE);
	dprintf(("trying to use addr %lx-%lx for shared arena\n", addr, addr+size));
	errno = 0;
	if ((addr = usconfig(CONF_ATTACHADDR, addr)) < 0 && errno != 0)
		perror("usconfig - CONF_ATTACHADDR (set)");
#endif
	if (usconfig(CONF_INITUSERS, 16) < 0)
		perror("usconfig - CONF_INITUSERS");
	my_pid = getpid();	/* so that we know which is the main thread */
	atexit(maybe_exit);
	s.sa_handler = exit_sig;
	sigemptyset(&s.sa_mask);
	/*sigaddset(&s.sa_mask, SIGUSR1);*/
	s.sa_flags = 0;
	sigaction(SIGUSR1, &s, 0);
	if (prctl(PR_SETEXITSIG, SIGUSR1) < 0)
		perror("prctl - PR_SETEXITSIG");
	if (usconfig(CONF_ARENATYPE, US_SHAREDONLY) < 0)
		perror("usconfig - CONF_ARENATYPE");
	/*usconfig(CONF_LOCKTYPE, US_DEBUGPLUS);*/
	if ((shared_arena = usinit(tmpnam(0))) == 0)
		perror("usinit");
#ifdef USE_DL
	if (usconfig(CONF_ATTACHADDR, addr) < 0) /* reset address */
		perror("usconfig - CONF_ATTACHADDR (reset)");
#endif
	if ((count_lock = usnewlock(shared_arena)) == NULL)
		perror("usnewlock (count_lock)");
	(void) usinitlock(count_lock);
	if ((wait_lock = usnewlock(shared_arena)) == NULL)
		perror("usnewlock (wait_lock)");
	dprintf(("arena start: %lx, arena size: %ld\n", (long) shared_arena, (long) usconfig(CONF_GETSIZE, shared_arena)));
#endif
#ifdef sun
	lwp_setstkcache(STACKSIZE, NSTACKS);
#endif
#ifdef C_THREADS
	cthread_init();
#endif
}

/*
 * Thread support.
 */
int start_new_thread _P2(func, void (*func) _P((void *)), arg, void *arg)
{
#ifdef sun
	thread_t tid;
#endif
#if defined(__sgi) && defined(USE_DL)
	long addr, size;
	static int local_initialized = 0;
#endif
	int success = 0;	/* init not needed when SOLARIS and */
				/* C_THREADS implemented properly */

	dprintf(("start_new_thread called\n"));
	if (!initialized)
		init_thread();
#ifdef __sgi
	switch (ussetlock(count_lock)) {
	case 0: return 0;
	case -1: perror("ussetlock (count_lock)");
	}
	if (maxpidindex >= MAXPROC)
		success = -1;
	else {
#ifdef USE_DL
		if (!local_initialized) {
			if ((size = usconfig(CONF_INITSIZE, 64*1024)) < 0)
				perror("usconfig - CONF_INITSIZE (check)");
			if (usconfig(CONF_INITSIZE, size) < 0)
				perror("usconfig - CONF_INITSIZE (reset)");
			addr = (long) dl_getrange(size + HDR_SIZE);
			dprintf(("trying to use addr %lx-%lx for sproc\n", addr, addr+size));
			errno = 0;
			if ((addr = usconfig(CONF_ATTACHADDR, addr)) < 0 && errno != 0)
				perror("usconfig - CONF_ATTACHADDR (set)");
		}
#endif
		if ((success = sproc(func, PR_SALL, arg)) < 0)
			perror("sproc");
#ifdef USE_DL
		if (!local_initialized) {
			if (usconfig(CONF_ATTACHADDR, addr) < 0) /* reset address */
				perror("usconfig - CONF_ATTACHADDR (reset)");
			local_initialized = 1;
		}
#endif
		if (success >= 0) {
			nthreads++;
			pidlist[maxpidindex++] = success;
		}
	}
	if (usunsetlock(count_lock) < 0)
		perror("usunsetlock (count_lock)");
#endif
#ifdef SOLARIS
	(void) thread_create(0, 0, func, arg, THREAD_NEW_LWP);
#endif
#ifdef sun
	success = lwp_create(&tid, func, MINPRIO, 0, lwp_newstk(), 1, arg);
#endif
#ifdef C_THREADS
	(void) cthread_fork(func, arg);
#endif
	return success < 0 ? 0 : 1;
}

static void do_exit_thread _P1(no_cleanup, int no_cleanup)
{
	dprintf(("exit_thread called\n"));
	if (!initialized)
		if (no_cleanup)
			_exit(0);
		else
			exit(0);
#ifdef __sgi
	if (ussetlock(count_lock) < 0)
		perror("ussetlock (count_lock)");
	nthreads--;
	if (getpid() == my_pid) {
		/* main thread; wait for other threads to exit */
		exiting = 1;
		if (do_exit) {
			int i;

			/* notify other threads */
			if (nthreads >= 0) {
				dprintf(("kill other threads\n"));
				for (i = 0; i < maxpidindex; i++)
					(void) kill(pidlist[i], SIGKILL);
				_exit(exit_status);
			}
		}
		waiting_for_threads = 1;
		if (ussetlock(wait_lock) < 0)
			perror("ussetlock (wait_lock)");
		for (;;) {
			if (nthreads < 0) {
				dprintf(("really exit (%d)\n", exit_status));
				if (no_cleanup)
					_exit(exit_status);
				else
					exit(exit_status);
			}
			if (usunsetlock(count_lock) < 0)
				perror("usunsetlock (count_lock)");
			dprintf(("waiting for other threads (%d)\n", nthreads));
			if (ussetlock(wait_lock) < 0)
				perror("ussetlock (wait_lock)");
			if (ussetlock(count_lock) < 0)
				perror("ussetlock (count_lock)");
		}
	}
	/* not the main thread */
	if (waiting_for_threads) {
		dprintf(("main thread is waiting\n"));
		if (usunsetlock(wait_lock) < 0)
			perror("usunsetlock (wait_lock)");
	} else if (do_exit)
		(void) kill(my_pid, SIGUSR1);
	if (usunsetlock(count_lock) < 0)
		perror("usunsetlock (count_lock)");
	_exit(0);
#endif
#ifdef SOLARIS
	thread_exit();
#endif
#ifdef sun
	lwp_destroy(SELF);
#endif
#ifdef C_THREADS
	cthread_exit(0);
#endif
}

void exit_thread _P0()
{
	do_exit_thread(0);
}

void _exit_thread _P0()
{
	do_exit_thread(1);
}

static void do_exit_prog _P2(status, int status, no_cleanup, int no_cleanup)
{
	dprintf(("exit_prog(%d) called\n", status));
	if (!initialized)
		if (no_cleanup)
			_exit(status);
		else
			exit(status);
#ifdef __sgi
	do_exit = 1;
	exit_status = status;
	do_exit_thread(no_cleanup);
#endif
#ifdef sun
	pod_exit(status);
#endif
}

void exit_prog _P1(status, int status)
{
	do_exit_prog(status, 0);
}

void _exit_prog _P1(status, int status)
{
	do_exit_prog(status, 1);
}

/*
 * Lock support.
 */
type_lock allocate_lock _P0()
{
#ifdef __sgi
	ulock_t lock;
#endif
#ifdef sun
	struct lock *lock;
	extern char *malloc();
#endif

	dprintf(("allocate_lock called\n"));
	if (!initialized)
		init_thread();

#ifdef __sgi
	if ((lock = usnewlock(shared_arena)) == NULL)
		perror("usnewlock");
	(void) usinitlock(lock);
#endif
#ifdef sun
	lock = (struct lock *) malloc(sizeof(struct lock));
	lock->lock_locked = 0;
	(void) mon_create(&lock->lock_monitor);
	(void) cv_create(&lock->lock_condvar, lock->lock_monitor);
#endif
	dprintf(("allocate_lock() -> %lx\n", (long)lock));
	return (type_lock) lock;
}

void free_lock _P1(lock, type_lock lock)
{
	dprintf(("free_lock(%lx) called\n", (long)lock));
#ifdef __sgi
	usfreelock((ulock_t) lock, shared_arena);
#endif
#ifdef sun
	mon_destroy(((struct lock *) lock)->lock_monitor);
	free((char *) lock);
#endif
}

int acquire_lock _P2(lock, type_lock lock, waitflag, int waitflag)
{
	int success;

	dprintf(("acquire_lock(%lx, %d) called\n", (long)lock, waitflag));
#ifdef __sgi
	errno = 0;		/* clear it just in case */
	if (waitflag)
		success = ussetlock((ulock_t) lock);
	else
		success = uscsetlock((ulock_t) lock, 1); /* Try it once */
	if (success < 0)
		perror(waitflag ? "ussetlock" : "uscsetlock");
#endif
#ifdef sun
	success = 0;

	(void) mon_enter(((struct lock *) lock)->lock_monitor);
	if (waitflag)
		while (((struct lock *) lock)->lock_locked)
			cv_wait(((struct lock *) lock)->lock_condvar);
	if (!((struct lock *) lock)->lock_locked) {
		success = 1;
		((struct lock *) lock)->lock_locked = 1;
	}
	cv_broadcast(((struct lock *) lock)->lock_condvar);
	mon_exit(((struct lock *) lock)->lock_monitor);
#endif
	dprintf(("acquire_lock(%lx, %d) -> %d\n", (long)lock, waitflag, success));
	return success;
}

void release_lock _P1(lock, type_lock lock)
{
	dprintf(("release_lock(%lx) called\n", (long)lock));
#ifdef __sgi
	if (usunsetlock((ulock_t) lock) < 0)
		perror("usunsetlock");
#endif
#ifdef sun
	(void) mon_enter(((struct lock *) lock)->lock_monitor);
	((struct lock *) lock)->lock_locked = 0;
	cv_broadcast(((struct lock *) lock)->lock_condvar);
	mon_exit(((struct lock *) lock)->lock_monitor);
#endif
}

/*
 * Semaphore support.
 */
type_sema allocate_sema _P1(value, int value)
{
#ifdef __sgi
	usema_t *sema;
#endif

	dprintf(("allocate_sema called\n"));
	if (!initialized)
		init_thread();

#ifdef __sgi
	if ((sema = usnewsema(shared_arena, value)) == NULL)
		perror("usnewsema");
	dprintf(("allocate_sema() -> %lx\n", (long) sema));
	return (type_sema) sema;
#endif
}

void free_sema _P1(sema, type_sema sema)
{
	dprintf(("free_sema(%lx) called\n", (long) sema));
#ifdef __sgi
	usfreesema((usema_t *) sema, shared_arena);
#endif
}

void down_sema _P1(sema, type_sema sema)
{
	dprintf(("down_sema(%lx) called\n", (long) sema));
#ifdef __sgi
	if (uspsema((usema_t *) sema) < 0)
		perror("uspsema");
#endif
	dprintf(("down_sema(%lx) return\n", (long) sema));
}

void up_sema _P1(sema, type_sema sema)
{
	dprintf(("up_sema(%lx)\n", (long) sema));
#ifdef __sgi
	if (usvsema((usema_t *) sema) < 0)
		perror("usvsema");
#endif
}