cpython/Python/thread.c

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#include "thread.h"
#ifdef DEBUG
#define dprintf(args) 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>
#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;
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;
#endif
dprintf(("init_thread called\n"));
if (initialized)
return;
initialized = 1;
#ifdef __sgi
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);
prctl(PR_SETEXITSIG, SIGUSR1);
usconfig(CONF_ARENATYPE, US_SHAREDONLY);
/*usconfig(CONF_LOCKTYPE, US_DEBUGPLUS);*/
shared_arena = usinit(tmpnam(0));
count_lock = usnewlock(shared_arena);
(void) usinitlock(count_lock);
wait_lock = usnewlock(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
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
if (ussetlock(count_lock) == 0)
return 0;
if (maxpidindex >= MAXPROC)
success = -1;
else {
success = sproc(func, PR_SALL, arg);
if (success >= 0) {
nthreads++;
pidlist[maxpidindex++] = success;
}
}
(void) 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
(void) 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 */
for (i = 0; i < maxpidindex; i++)
(void) kill(pidlist[i], SIGUSR1);
}
waiting_for_threads = 1;
ussetlock(wait_lock);
for (;;) {
if (nthreads < 0) {
dprintf(("really exit (%d)\n", exit_status));
if (no_cleanup)
_exit(exit_status);
else
exit(exit_status);
}
usunsetlock(count_lock);
dprintf(("waiting for other threads (%d)\n", nthreads));
ussetlock(wait_lock);
ussetlock(count_lock);
}
}
/* not the main thread */
if (waiting_for_threads) {
dprintf(("main thread is waiting\n"));
usunsetlock(wait_lock);
}
(void) 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
lock = usnewlock(shared_arena);
(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
if (waitflag)
success = ussetlock((ulock_t) lock);
else
success = uscsetlock((ulock_t) lock, 1); /* Try it once */
#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
(void) usunsetlock((ulock_t) lock);
#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"));
#ifdef __sgi
sema = usnewsema(shared_arena, value);
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
(void) uspsema((usema_t *) sema);
#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
(void) usvsema((usema_t *) sema);
#endif
}