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pthreads.subproj/pthread.c /dev/null Libc-186
--- /dev/null
+++ Libc/Libc-186/pthreads.subproj/pthread.c
@@ -0,0 +1,1256 @@
+/*
+ * Copyright 1996 1995 by Open Software Foundation, Inc. 1997 1996 1995 1994 1993 1992 1991  
+ *              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 appears in all copies and 
+ * that both the copyright notice and this permission notice appear in 
+ * supporting documentation. 
+ *  
+ * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE 
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
+ * FOR A PARTICULAR PURPOSE. 
+ *  
+ * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR 
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, 
+ * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 
+ * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
+ * 
+ */
+/*
+ * MkLinux
+ */
+
+/*
+ * POSIX Pthread Library
+ */
+
+#define __POSIX_LIB__
+#include <assert.h>
+#include <stdio.h>	/* For printf(). */
+#include <stdlib.h>
+#include <errno.h>	/* For __mach_errno_addr() prototype. */
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/sysctl.h>
+#include <machine/vmparam.h>
+#include <mach/vm_statistics.h>
+
+#include "pthread_internals.h"
+
+/* Per-thread kernel support */
+extern void _pthread_set_self(pthread_t);
+extern void mig_init(int);
+
+/* Needed to tell the malloc subsystem we're going multithreaded */
+extern void set_malloc_singlethreaded(int);
+
+/* Used when we need to call into the kernel with no reply port */
+extern pthread_lock_t reply_port_lock;
+
+/*
+ * [Internal] stack support
+ */
+
+size_t _pthread_stack_size = 0;
+int _spin_tries = 0;
+#if !defined(__ppc__)
+int _cpu_has_altivec = 0;
+#endif
+
+/* This global should be used (carefully) by anyone needing to know if a pthread has been
+** created.
+*/
+int __is_threaded = 0;
+
+/* These are used to keep track of a semaphore pool shared by mutexes and condition
+** variables.
+*/
+
+static semaphore_t *sem_pool = NULL;
+static int sem_pool_count = 0;
+static int sem_pool_current = 0;
+static pthread_lock_t sem_pool_lock = LOCK_INITIALIZER;
+
+static int default_priority;
+static int max_priority;
+static int min_priority;
+
+extern mach_port_t thread_recycle_port;
+
+#define STACK_LOWEST(sp)	((sp) & ~__pthread_stack_mask)
+#define STACK_RESERVED		(sizeof (struct _pthread))
+
+#ifdef STACK_GROWS_UP
+
+/* The stack grows towards higher addresses:
+   |struct _pthread|user stack---------------->|
+   ^STACK_BASE     ^STACK_START
+   ^STACK_SELF
+   ^STACK_LOWEST  */
+#define STACK_BASE(sp)		STACK_LOWEST(sp)
+#define STACK_START(stack_low)	(STACK_BASE(stack_low) + STACK_RESERVED)
+#define STACK_SELF(sp)		STACK_BASE(sp)
+
+#else
+
+/* The stack grows towards lower addresses:
+   |<----------------user stack|struct _pthread|
+   ^STACK_LOWEST               ^STACK_START    ^STACK_BASE
+			       ^STACK_SELF  */
+
+#define STACK_BASE(sp)		(((sp) | __pthread_stack_mask) + 1)
+#define STACK_START(stack_low)	(STACK_BASE(stack_low) - STACK_RESERVED)
+#define STACK_SELF(sp)		STACK_START(sp)
+
+#endif
+
+/* Set the base address to use as the stack pointer, before adjusting due to the ABI */
+
+static int
+_pthread_allocate_stack(pthread_attr_t *attrs, vm_address_t *stack)
+{
+    kern_return_t kr;
+#if 1
+    assert(attrs->stacksize >= PTHREAD_STACK_MIN);
+    if (attrs->stackaddr != NULL) {
+        assert(((vm_offset_t)(attrs->stackaddr) & (vm_page_size - 1)) == 0);
+        *stack = (vm_address_t)attrs->stackaddr;
+        return 0;
+    }
+    kr = vm_allocate(mach_task_self(), stack, attrs->stacksize + vm_page_size, VM_MAKE_TAG(VM_MEMORY_STACK)| TRUE);
+    if (kr != KERN_SUCCESS) {
+        return EAGAIN;
+    }
+#ifdef STACK_GROWS_UP
+    /* The guard page is the page one higher than the stack */
+    /* The stack base is at the lowest address */
+    kr = vm_protect(mach_task_self(), *stack + attrs->stacksize, vm_page_size, FALSE, VM_PROT_NONE);
+#else
+    /* The guard page is at the lowest address */
+    /* The stack base is the highest address */
+    kr = vm_protect(mach_task_self(), *stack, vm_page_size, FALSE, VM_PROT_NONE);
+    *stack += attrs->stacksize + vm_page_size;
+#endif
+
+#else
+    vm_address_t cur_stack = (vm_address_t)0;
+	if (free_stacks == 0)
+	{
+	    /* Allocating guard pages is done by doubling
+	     * the actual stack size, since STACK_BASE() needs
+	     * to have stacks aligned on stack_size. Allocating just 
+	     * one page takes as much memory as allocating more pages
+	     * since it will remain one entry in the vm map.
+	     * Besides, allocating more than one page allows tracking the
+	     * overflow pattern when the overflow is bigger than one page.
+	     */
+#ifndef	NO_GUARD_PAGES
+# define	GUARD_SIZE(a)	(2*(a))
+# define	GUARD_MASK(a)	(((a)<<1) | 1)
+#else
+# define	GUARD_SIZE(a)	(a)
+# define	GUARD_MASK(a)	(a)
+#endif
+		while (lowest_stack > GUARD_SIZE(__pthread_stack_size))
+		{
+			lowest_stack -= GUARD_SIZE(__pthread_stack_size);
+			/* Ensure stack is there */
+			kr = vm_allocate(mach_task_self(),
+					 &lowest_stack,
+					 GUARD_SIZE(__pthread_stack_size),
+					 FALSE);
+#ifndef	NO_GUARD_PAGES
+			if (kr == KERN_SUCCESS) {
+# ifdef	STACK_GROWS_UP
+			    kr = vm_protect(mach_task_self(),
+					    lowest_stack+__pthread_stack_size,
+					    __pthread_stack_size,
+					    FALSE, VM_PROT_NONE);
+# else	/* STACK_GROWS_UP */
+			    kr = vm_protect(mach_task_self(),
+					    lowest_stack,
+					    __pthread_stack_size,
+					    FALSE, VM_PROT_NONE);
+			    lowest_stack += __pthread_stack_size;
+# endif	/* STACK_GROWS_UP */
+			    if (kr == KERN_SUCCESS)
+				break;
+			}
+#else
+			if (kr == KERN_SUCCESS)
+			    break;
+#endif
+		}
+		if (lowest_stack > 0)
+			free_stacks = (vm_address_t *)lowest_stack;
+		else
+		{
+			/* Too bad.  We'll just have to take what comes.
+			   Use vm_map instead of vm_allocate so we can
+			   specify alignment.  */
+			kr = vm_map(mach_task_self(), &lowest_stack,
+				    GUARD_SIZE(__pthread_stack_size),
+				    GUARD_MASK(__pthread_stack_mask),
+				    TRUE /* anywhere */, MEMORY_OBJECT_NULL,
+				    0, FALSE, VM_PROT_DEFAULT, VM_PROT_ALL,
+				    VM_INHERIT_DEFAULT);
+			/* This really shouldn't fail and if it does I don't
+			   know what to do.  */
+#ifndef	NO_GUARD_PAGES
+			if (kr == KERN_SUCCESS) {
+# ifdef	STACK_GROWS_UP
+			    kr = vm_protect(mach_task_self(),
+					    lowest_stack+__pthread_stack_size,
+					    __pthread_stack_size,
+					    FALSE, VM_PROT_NONE);
+# else	/* STACK_GROWS_UP */
+			    kr = vm_protect(mach_task_self(),
+					    lowest_stack,
+					    __pthread_stack_size,
+					    FALSE, VM_PROT_NONE);
+			    lowest_stack += __pthread_stack_size;
+# endif	/* STACK_GROWS_UP */
+			}
+#endif
+			free_stacks = (vm_address_t *)lowest_stack;
+			lowest_stack = 0;
+		}
+		*free_stacks = 0; /* No other free stacks */
+	}
+	cur_stack = STACK_START((vm_address_t) free_stacks);
+	free_stacks = (vm_address_t *)*free_stacks;
+	cur_stack = _adjust_sp(cur_stack); /* Machine dependent stack fudging */
+#endif
+        return 0;
+}
+
+/*
+ * Destroy a thread attribute structure
+ */
+int       
+pthread_attr_destroy(pthread_attr_t *attr)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		return (ESUCCESS);
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Get the 'detach' state from a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_getdetachstate(const pthread_attr_t *attr, 
+			    int *detachstate)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		*detachstate = attr->detached;
+		return (ESUCCESS);
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Get the 'inherit scheduling' info from a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_getinheritsched(const pthread_attr_t *attr, 
+			     int *inheritsched)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		*inheritsched = attr->inherit;
+		return (ESUCCESS);
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Get the scheduling parameters from a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_getschedparam(const pthread_attr_t *attr, 
+			   struct sched_param *param)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		*param = attr->param;
+		return (ESUCCESS);
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Get the scheduling policy from a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_getschedpolicy(const pthread_attr_t *attr, 
+			    int *policy)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		*policy = attr->policy;
+		return (ESUCCESS);
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+static const size_t DEFAULT_STACK_SIZE = DFLSSIZ;
+/*
+ * Initialize a thread attribute structure to default values.
+ */
+int       
+pthread_attr_init(pthread_attr_t *attr)
+{
+        attr->stacksize = DEFAULT_STACK_SIZE;
+        attr->stackaddr = NULL;
+	attr->sig = _PTHREAD_ATTR_SIG;
+	attr->policy = _PTHREAD_DEFAULT_POLICY;
+	attr->param.sched_priority = default_priority;
+	attr->param.quantum = 10; /* quantum isn't public yet */
+	attr->inherit = _PTHREAD_DEFAULT_INHERITSCHED;
+	attr->detached = PTHREAD_CREATE_JOINABLE;
+        attr->freeStackOnExit = TRUE;
+	return (ESUCCESS);
+}
+
+/*
+ * Set the 'detach' state in a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_setdetachstate(pthread_attr_t *attr, 
+			    int detachstate)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		if ((detachstate == PTHREAD_CREATE_JOINABLE) ||
+		    (detachstate == PTHREAD_CREATE_DETACHED))
+		{
+			attr->detached = detachstate;
+			return (ESUCCESS);
+		} else
+		{
+			return (EINVAL);
+		}
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Set the 'inherit scheduling' state in a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_setinheritsched(pthread_attr_t *attr, 
+			     int inheritsched)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		if ((inheritsched == PTHREAD_INHERIT_SCHED) ||
+		    (inheritsched == PTHREAD_EXPLICIT_SCHED))
+		{
+			attr->inherit = inheritsched;
+			return (ESUCCESS);
+		} else
+		{
+			return (EINVAL);
+		}
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Set the scheduling paramters in a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_setschedparam(pthread_attr_t *attr, 
+			   const struct sched_param *param)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		/* TODO: Validate sched_param fields */
+		attr->param = *param;
+		return (ESUCCESS);
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Set the scheduling policy in a thread attribute structure.
+ * Note: written as a helper function for info hiding
+ */
+int       
+pthread_attr_setschedpolicy(pthread_attr_t *attr, 
+			    int policy)
+{
+	if (attr->sig == _PTHREAD_ATTR_SIG)
+	{
+		if ((policy == SCHED_OTHER) ||
+		    (policy == SCHED_RR) ||
+		    (policy == SCHED_FIFO))
+		{
+			attr->policy = policy;
+			return (ESUCCESS);
+		} else
+		{
+			return (EINVAL);
+		}
+	} else
+	{
+		return (EINVAL); /* Not an attribute structure! */
+	}
+}
+
+/*
+ * Set the scope for the thread.
+ * We currently only provide PTHREAD_SCOPE_SYSTEM
+ */
+int
+pthread_attr_setscope(pthread_attr_t *attr,
+                            int scope)
+{
+    if (attr->sig == _PTHREAD_ATTR_SIG) {
+        if (scope == PTHREAD_SCOPE_SYSTEM) {
+            /* No attribute yet for the scope */
+            return (ESUCCESS);
+        } else if (scope == PTHREAD_SCOPE_PROCESS) {
+            return (ENOTSUP);
+        }
+    }
+    return (EINVAL); /* Not an attribute structure! */
+}
+
+/*
+ * Get the scope for the thread.
+ * We currently only provide PTHREAD_SCOPE_SYSTEM
+ */
+int
+pthread_attr_getscope(pthread_attr_t *attr,
+                            int *scope)
+{
+    if (attr->sig == _PTHREAD_ATTR_SIG) {
+        *scope = PTHREAD_SCOPE_SYSTEM;
+        return (ESUCCESS);
+    }
+    return (EINVAL); /* Not an attribute structure! */
+}
+
+/* Get the base stack address of the given thread */
+int
+pthread_attr_getstackaddr(const pthread_attr_t *attr, void **stackaddr)
+{
+    if (attr->sig == _PTHREAD_ATTR_SIG) {
+        *stackaddr = attr->stackaddr;
+        return (ESUCCESS);
+    } else {
+        return (EINVAL); /* Not an attribute structure! */
+    }
+}
+
+int
+pthread_attr_setstackaddr(pthread_attr_t *attr, void *stackaddr)
+{
+    if ((attr->sig == _PTHREAD_ATTR_SIG) && (((vm_offset_t)stackaddr & (vm_page_size - 1)) == 0)) {
+        attr->stackaddr = stackaddr;
+        attr->freeStackOnExit = FALSE;
+        return (ESUCCESS);
+    } else {
+        return (EINVAL); /* Not an attribute structure! */
+    }
+}
+
+int
+pthread_attr_getstacksize(const pthread_attr_t *attr, size_t *stacksize)
+{
+    if (attr->sig == _PTHREAD_ATTR_SIG) {
+        *stacksize = attr->stacksize;
+        return (ESUCCESS);
+    } else {
+        return (EINVAL); /* Not an attribute structure! */
+    }
+}
+
+int
+pthread_attr_setstacksize(pthread_attr_t *attr, size_t stacksize)
+{
+    if ((attr->sig == _PTHREAD_ATTR_SIG) && ((stacksize % vm_page_size) == 0) && (stacksize >= PTHREAD_STACK_MIN)) {
+        attr->stacksize = stacksize;
+        return (ESUCCESS);
+    } else {
+        return (EINVAL); /* Not an attribute structure! */
+    }
+}
+
+/*
+ * Create and start execution of a new thread.
+ */
+
+static void
+_pthread_body(pthread_t self)
+{
+    _pthread_set_self(self);
+    pthread_exit((self->fun)(self->arg));
+}
+
+int
+_pthread_create(pthread_t t,
+		const pthread_attr_t *attrs,
+                vm_address_t stack,
+		const mach_port_t kernel_thread)
+{
+	int res;
+	kern_return_t kern_res;
+	res = ESUCCESS;
+	do
+	{
+		memset(t, 0, sizeof(*t));
+		t->stacksize = attrs->stacksize;
+                t->stackaddr = (void *)stack;
+                t->kernel_thread = kernel_thread;
+		t->detached = attrs->detached;
+		t->inherit = attrs->inherit;
+		t->policy = attrs->policy;
+		t->param = attrs->param;
+                t->freeStackOnExit = attrs->freeStackOnExit;
+		t->mutexes = (struct _pthread_mutex *)NULL;
+		t->sig = _PTHREAD_SIG;
+                t->reply_port = MACH_PORT_NULL;
+                t->cthread_self = NULL;
+		LOCK_INIT(t->lock);
+		t->cancel_state = PTHREAD_CANCEL_ENABLE | PTHREAD_CANCEL_DEFERRED;
+		t->cleanup_stack = (struct _pthread_handler_rec *)NULL;
+		pthread_setschedparam(t, t->policy, &t->param);
+		/* Create control semaphores */
+		if (t->detached == PTHREAD_CREATE_JOINABLE)
+		{
+			PTHREAD_MACH_CALL(semaphore_create(mach_task_self(), 
+						   &t->death, 
+						   SYNC_POLICY_FIFO, 
+						   0), kern_res);
+			if (kern_res != KERN_SUCCESS)
+			{
+				printf("Can't create 'death' semaphore: %d\n", kern_res);
+				res = EINVAL; /* Need better error here? */
+				break;
+			}
+			PTHREAD_MACH_CALL(semaphore_create(mach_task_self(), 
+						   &t->joiners, 
+						   SYNC_POLICY_FIFO, 
+						   0), kern_res);
+			if (kern_res != KERN_SUCCESS)
+			{
+				printf("Can't create 'joiners' semaphore: %d\n", kern_res);
+				res = EINVAL; /* Need better error here? */
+				break;
+			}
+			t->num_joiners = 0;
+		} else
+		{
+			t->death = MACH_PORT_NULL;
+		}
+	} while (0);
+	return (res);
+}
+
+int
+_pthread_is_threaded(void)
+{
+    return __is_threaded;
+}
+
+mach_port_t
+pthread_mach_thread_np(pthread_t t)
+{
+    return t->kernel_thread;
+}
+
+size_t
+pthread_get_stacksize_np(pthread_t t)
+{
+    return t->stacksize;
+}
+
+void *
+pthread_get_stackaddr_np(pthread_t t)
+{
+    return t->stackaddr;
+}
+
+mach_port_t
+_pthread_reply_port(pthread_t t)
+{
+    return t->reply_port;
+}
+
+static int       
+_pthread_create_suspended(pthread_t *thread, 
+	       const pthread_attr_t *attr,
+	       void *(*start_routine)(void *), 
+	       void *arg,
+           int suspended)
+{
+	pthread_attr_t _attr, *attrs;
+	vm_address_t stack;
+	int res;
+	pthread_t t;
+	kern_return_t kern_res;
+	mach_port_t kernel_thread;
+	if ((attrs = (pthread_attr_t *)attr) == (pthread_attr_t *)NULL)
+	{			/* Set up default paramters */
+		attrs = &_attr;
+		pthread_attr_init(attrs);
+        } else if (attrs->sig != _PTHREAD_ATTR_SIG) {
+            return EINVAL;
+        }
+	res = ESUCCESS;
+	do
+	{
+		/* Allocate a stack for the thread */
+                if ((res = _pthread_allocate_stack(attrs, &stack)) != 0) {
+                    break;
+                }
+		t = (pthread_t)malloc(sizeof(struct _pthread));
+		*thread = t;
+		/* Create the Mach thread for this thread */
+		PTHREAD_MACH_CALL(thread_create(mach_task_self(), &kernel_thread), kern_res);
+		if (kern_res != KERN_SUCCESS)
+		{
+			printf("Can't create thread: %d\n", kern_res);
+			res = EINVAL; /* Need better error here? */
+			break;
+		}
+                if ((res = _pthread_create(t, attrs, stack, kernel_thread)) != 0)
+		{
+			break;
+		}
+		t->arg = arg;
+		t->fun = start_routine;
+		/* Now set it up to execute */
+		_pthread_setup(t, _pthread_body, stack);
+		/* Send it on it's way */
+                set_malloc_singlethreaded(0);
+		__is_threaded = 1;
+        if (suspended == 0) {
+            PTHREAD_MACH_CALL(thread_resume(kernel_thread), kern_res);
+        }
+		if (kern_res != KERN_SUCCESS)
+		{
+			printf("Can't resume thread: %d\n", kern_res);
+			res = EINVAL; /* Need better error here? */
+			break;
+		}
+	} while (0);
+	return (res);
+}
+
+int
+pthread_create(pthread_t *thread,
+           const pthread_attr_t *attr,
+           void *(*start_routine)(void *),
+           void *arg)
+{
+    return _pthread_create_suspended(thread, attr, start_routine, arg, 0);
+}
+
+int
+pthread_create_suspended_np(pthread_t *thread,
+           const pthread_attr_t *attr,
+           void *(*start_routine)(void *),
+           void *arg)
+{
+    return _pthread_create_suspended(thread, attr, start_routine, arg, 1);
+}
+
+/*
+ * Make a thread 'undetached' - no longer 'joinable' with other threads.
+ */
+int       
+pthread_detach(pthread_t thread)
+{
+	kern_return_t kern_res;
+	int num_joiners;
+	mach_port_t death;
+	if (thread->sig == _PTHREAD_SIG)
+	{
+		LOCK(thread->lock);
+		if (thread->detached == PTHREAD_CREATE_JOINABLE)
+		{
+			thread->detached = PTHREAD_CREATE_DETACHED;
+			num_joiners = thread->num_joiners;
+			death = thread->death;
+			thread->death = MACH_PORT_NULL;
+			UNLOCK(thread->lock);
+			if (num_joiners > 0)
+			{
+				/* Wake up a joiner */
+				PTHREAD_MACH_CALL(semaphore_signal(thread->joiners), kern_res);
+			}
+			/* Destroy 'control' semaphores */
+			PTHREAD_MACH_CALL(semaphore_destroy(mach_task_self(),
+						    thread->joiners), kern_res);
+			PTHREAD_MACH_CALL(semaphore_destroy(mach_task_self(),
+						    death), kern_res);
+			return (ESUCCESS);
+		} else if (thread->detached == _PTHREAD_EXITED) {
+			UNLOCK(thread->lock);
+			pthread_join(thread, NULL);
+			return ESUCCESS;
+		} else
+		{
+			UNLOCK(thread->lock);
+			return (EINVAL);
+		}
+	} else
+	{
+		return (ESRCH); /* Not a valid thread */
+	}
+}
+
+/* Announce that there is a thread ready to be reclaimed for pthread_create */
+/* or terminated by pthread_exit. If the thread is reused, it will have its */
+/* thread state set and will continue in the thread body function. If it is */
+/* terminated, it will be yanked out from under the mach_msg() call. */
+
+static void _pthread_become_available(pthread_t thread) {
+	mach_msg_empty_rcv_t msg = { { 0 } };
+	kern_return_t ret;
+
+	if (thread->reply_port == MACH_PORT_NULL) {
+		thread->reply_port = mach_reply_port();
+	}
+	msg.header.msgh_size = sizeof msg - sizeof msg.trailer;
+	msg.header.msgh_remote_port = thread_recycle_port;
+	msg.header.msgh_local_port = MACH_PORT_NULL; 
+	msg.header.msgh_id = (int)thread;
+	msg.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
+	ret = mach_msg(&msg.header, MACH_SEND_MSG | MACH_RCV_MSG,
+			msg.header.msgh_size, sizeof msg,
+			thread->reply_port, MACH_MSG_TIMEOUT_NONE,
+			MACH_PORT_NULL);
+	while (1) {
+		ret = thread_suspend(thread->kernel_thread);
+	}
+	/* We should never get here */
+}
+
+/* Check to see if any threads are available. Return immediately */
+
+static kern_return_t _pthread_check_for_available_threads(mach_msg_empty_rcv_t *msg) {
+	return mach_msg(&msg->header, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0,
+			sizeof(mach_msg_empty_rcv_t), thread_recycle_port, 0,
+			MACH_PORT_NULL);
+}
+
+/* Terminate all available threads and deallocate their stacks */
+static void _pthread_reap_threads(void) {
+	kern_return_t ret;
+	mach_msg_empty_rcv_t msg = { { 0 } };
+	while((ret = _pthread_check_for_available_threads(&msg)) == KERN_SUCCESS) {
+		pthread_t th = (pthread_t)msg.header.msgh_id;
+		mach_port_t kernel_thread = th->kernel_thread;
+		mach_port_t reply_port = th->reply_port; 
+		vm_size_t size = (vm_size_t)th->stacksize + vm_page_size;
+		vm_address_t addr = (vm_address_t)th->stackaddr;
+#if !defined(STACK_GROWS_UP)
+		addr -= size;
+#endif
+		ret = thread_terminate(kernel_thread);
+		if (ret != KERN_SUCCESS) {
+			fprintf(stderr, "thread_terminate() failed: %s\n",
+				mach_error_string(ret));
+		}
+		ret = mach_port_destroy(mach_task_self(), reply_port);
+		if (ret != KERN_SUCCESS) {
+			fprintf(stderr,
+				"mach_port_destroy(thread_reply) failed: %s\n",
+				mach_error_string(ret));
+		}
+		if (th->freeStackOnExit) {
+			ret = vm_deallocate(mach_task_self(), addr, size);
+			if (ret != KERN_SUCCESS) {
+				fprintf(stderr,
+					"vm_deallocate(stack) failed: %s\n",
+					mach_error_string(ret));
+			}
+		}
+		free(th);
+	}
+	assert(ret == MACH_RCV_TIMED_OUT);
+}
+
+/* For compatibility... */
+
+pthread_t
+_pthread_self() {
+	return pthread_self();
+}
+
+/*
+ * Terminate a thread.
+ */
+void 
+pthread_exit(void *value_ptr)
+{
+	pthread_t self = pthread_self();
+        struct _pthread_handler_rec *handler;
+	kern_return_t kern_res;
+	int num_joiners;
+	while ((handler = self->cleanup_stack) != 0)
+	{
+		(handler->routine)(handler->arg);
+		self->cleanup_stack = handler->next;
+	}
+	_pthread_tsd_cleanup(self);
+	LOCK(self->lock);
+	if (self->detached == PTHREAD_CREATE_JOINABLE)
+	{
+		self->detached = _PTHREAD_EXITED;
+		self->exit_value = value_ptr;
+		num_joiners = self->num_joiners;
+		UNLOCK(self->lock);
+		if (num_joiners > 0)
+		{
+			/* POSIX says that multiple pthread_join() calls on */
+			/* the same thread are undefined so we just wake up */
+			/* the first one to join */
+			PTHREAD_MACH_CALL(semaphore_signal(self->joiners), kern_res);
+		}
+		do {
+			PTHREAD_MACH_CALL(semaphore_wait(self->death), kern_res);
+		} while (kern_res == KERN_ABORTED);
+	} else
+		UNLOCK(self->lock);
+	/* Destroy thread & reclaim resources */
+	if (self->death)
+	{
+		PTHREAD_MACH_CALL(semaphore_destroy(mach_task_self(), self->joiners), kern_res);
+		PTHREAD_MACH_CALL(semaphore_destroy(mach_task_self(), self->death), kern_res);
+	}
+        if (self->detached == _PTHREAD_CREATE_PARENT) {
+		exit((int)(self->exit_value));
+	}
+
+	_pthread_reap_threads();
+        
+	_pthread_become_available(self);
+}
+
+/*
+ * Wait for a thread to terminate and obtain its exit value.
+ */
+int       
+pthread_join(pthread_t thread, 
+	     void **value_ptr)
+{
+	kern_return_t kern_res;
+	if (thread->sig == _PTHREAD_SIG)
+	{
+		LOCK(thread->lock);
+		if (thread->detached == PTHREAD_CREATE_JOINABLE)
+		{
+			thread->num_joiners++;
+			UNLOCK(thread->lock);
+			do {
+				PTHREAD_MACH_CALL(semaphore_wait(thread->joiners), kern_res);
+			 } while (kern_res == KERN_ABORTED);
+			LOCK(thread->lock);
+			thread->num_joiners--;
+		}
+		if (thread->detached == _PTHREAD_EXITED)
+		{
+			if (thread->num_joiners == 0)
+			{	/* Give the result to this thread */
+				if (value_ptr)
+				{
+					*value_ptr = thread->exit_value;
+				}
+				UNLOCK(thread->lock);
+				PTHREAD_MACH_CALL(semaphore_signal(thread->death), kern_res);
+				return (ESUCCESS);
+			} else
+			{	/* This 'joiner' missed the catch! */
+				UNLOCK(thread->lock);
+				return (ESRCH);
+			}
+		} else
+		{		/* The thread has become anti-social! */
+			UNLOCK(thread->lock);
+			return (EINVAL);
+		}
+	} else
+	{
+		return (ESRCH); /* Not a valid thread */
+	}
+}
+
+/*
+ * Get the scheduling policy and scheduling paramters for a thread.
+ */
+int       
+pthread_getschedparam(pthread_t thread, 
+		      int *policy,
+		      struct sched_param *param)
+{
+	if (thread->sig == _PTHREAD_SIG)
+	{
+            *policy = thread->policy;
+            *param = thread->param;
+            return (ESUCCESS);
+	} else
+	{
+		return (ESRCH);  /* Not a valid thread structure */
+	}
+}
+
+/*
+ * Set the scheduling policy and scheduling paramters for a thread.
+ */
+int       
+pthread_setschedparam(pthread_t thread, 
+		      int policy,
+		      const struct sched_param *param)
+{
+	policy_base_data_t bases;
+	policy_base_t base;
+	mach_msg_type_number_t count;
+	kern_return_t ret;
+
+	if (thread->sig == _PTHREAD_SIG)
+	{
+		switch (policy)
+		{
+		case SCHED_OTHER:
+			bases.ts.base_priority = param->sched_priority;
+			base = (policy_base_t)&bases.ts;
+			count = POLICY_TIMESHARE_BASE_COUNT;
+			break;
+		case SCHED_FIFO:
+			bases.fifo.base_priority = param->sched_priority;
+			base = (policy_base_t)&bases.fifo;
+			count = POLICY_FIFO_BASE_COUNT;
+			break;
+		case SCHED_RR:
+			bases.rr.base_priority = param->sched_priority;
+			/* quantum isn't public yet */
+			bases.rr.quantum = param->quantum;
+			base = (policy_base_t)&bases.rr;
+			count = POLICY_RR_BASE_COUNT;
+			break;
+		default:
+			return (EINVAL);
+		}
+            thread->policy = policy;
+            thread->param = *param;
+		ret = thread_policy(thread->kernel_thread, policy, base, count, TRUE);
+		if (ret != KERN_SUCCESS)
+		{
+			return (EINVAL);
+		}
+		return (ESUCCESS);
+	} else
+	{
+		return (ESRCH);  /* Not a valid thread structure */
+	}
+}
+
+/*
+ * Get the minimum priority for the given policy
+ */
+int
+sched_get_priority_min(int policy)
+{
+    return default_priority - 16;
+}
+
+/*
+ * Get the maximum priority for the given policy
+ */
+int
+sched_get_priority_max(int policy)
+{
+    return default_priority + 16;
+}
+
+/*
+ * Determine if two thread identifiers represent the same thread.
+ */
+int       
+pthread_equal(pthread_t t1, 
+	      pthread_t t2)
+{
+	return (t1 == t2);
+}
+
+void 
+cthread_set_self(void *cself)
+{
+    pthread_t self = pthread_self();
+    if ((self == (pthread_t)NULL) || (self->sig != _PTHREAD_SIG)) {
+        _pthread_set_self(cself);
+        return;
+    }
+    self->cthread_self = cself;
+}
+
+void *
+ur_cthread_self(void) {
+    pthread_t self = pthread_self();
+    if ((self == (pthread_t)NULL) || (self->sig != _PTHREAD_SIG)) {
+        return (void *)self;
+    }
+    return self->cthread_self;
+}
+
+/*
+ * Execute a function exactly one time in a thread-safe fashion.
+ */
+int       
+pthread_once(pthread_once_t *once_control, 
+	     void (*init_routine)(void))
+{
+	LOCK(once_control->lock);
+	if (once_control->sig == _PTHREAD_ONCE_SIG_init)
+	{
+		(*init_routine)();
+		once_control->sig = _PTHREAD_ONCE_SIG;
+	}
+	UNLOCK(once_control->lock);
+	return (ESUCCESS);  /* Spec defines no possible errors! */
+}
+
+/*
+ * Cancel a thread
+ */
+int
+pthread_cancel(pthread_t thread)
+{
+	if (thread->sig == _PTHREAD_SIG)
+	{
+		thread->cancel_state |= _PTHREAD_CANCEL_PENDING;
+		return (ESUCCESS);
+	} else
+	{
+		return (ESRCH);
+	}
+}
+
+/*
+ * Insert a cancellation point in a thread.
+ */
+static void
+_pthread_testcancel(pthread_t thread)
+{
+	LOCK(thread->lock);
+	if ((thread->cancel_state & (PTHREAD_CANCEL_ENABLE|_PTHREAD_CANCEL_PENDING)) == 
+	    (PTHREAD_CANCEL_ENABLE|_PTHREAD_CANCEL_PENDING))
+	{
+		UNLOCK(thread->lock);
+		pthread_exit(0);
+	}
+	UNLOCK(thread->lock);
+}
+
+void
+pthread_testcancel(void)
+{
+	pthread_t self = pthread_self();
+	_pthread_testcancel(self);
+}
+
+/*
+ * Query/update the cancelability 'state' of a thread
+ */
+int
+pthread_setcancelstate(int state, int *oldstate)
+{
+	pthread_t self = pthread_self();
+	int err = ESUCCESS;
+	LOCK(self->lock);
+	*oldstate = self->cancel_state & _PTHREAD_CANCEL_STATE_MASK;
+	if ((state == PTHREAD_CANCEL_ENABLE) || (state == PTHREAD_CANCEL_DISABLE))
+	{
+		self->cancel_state = (self->cancel_state & _PTHREAD_CANCEL_STATE_MASK) | state;
+	} else
+	{
+		err = EINVAL;
+	}
+	UNLOCK(self->lock);
+	_pthread_testcancel(self);  /* See if we need to 'die' now... */
+	return (err);
+}
+
+/*
+ * Query/update the cancelability 'type' of a thread
+ */
+int
+pthread_setcanceltype(int type, int *oldtype)
+{
+	pthread_t self = pthread_self();
+	int err = ESUCCESS;
+	LOCK(self->lock);
+	*oldtype = self->cancel_state & _PTHREAD_CANCEL_TYPE_MASK;
+	if ((type == PTHREAD_CANCEL_DEFERRED) || (type == PTHREAD_CANCEL_ASYNCHRONOUS))
+	{
+		self->cancel_state = (self->cancel_state & _PTHREAD_CANCEL_TYPE_MASK) | type;
+	} else
+	{
+		err = EINVAL;
+	}
+	UNLOCK(self->lock);
+	_pthread_testcancel(self);  /* See if we need to 'die' now... */
+	return (err);
+}
+
+/*
+ * Perform package initialization - called automatically when application starts
+ */
+
+/* We'll implement this when the main thread is a pthread */
+/* Use the local _pthread struct to avoid malloc before our MiG reply port is set */
+
+static struct _pthread _thread = {0};
+
+static int
+pthread_init(void)
+{
+	pthread_attr_t _attr, *attrs;
+        pthread_t thread;
+	kern_return_t kr;
+	host_basic_info_data_t basic_info;
+	host_priority_info_data_t priority_info;
+	host_info_t info;
+	host_flavor_t flavor;
+	mach_msg_type_number_t count;
+	int mib[2];
+	size_t len;
+	int hasvectorunit, numcpus;
+
+        count = HOST_PRIORITY_INFO_COUNT;
+	info = (host_info_t)&priority_info;
+	flavor = HOST_PRIORITY_INFO;
+	kr = host_info(mach_host_self(), flavor, info, &count);
+        if (kr != KERN_SUCCESS)
+                printf("host_info failed (%d); probably need privilege.\n", kr);
+        else {
+		default_priority = priority_info.user_priority;
+            min_priority = priority_info.minimum_priority;
+            max_priority = priority_info.maximum_priority;
+	}
+	attrs = &_attr;
+	pthread_attr_init(attrs);
+	_pthread_set_self(&_thread);
+
+        _pthread_create(&_thread, attrs, USRSTACK, mach_thread_self());
+        thread = &_thread;
+        thread->detached = _PTHREAD_CREATE_PARENT;
+
+        /* See if we're on a multiprocessor and set _spin_tries if so.  */
+	mib[0] = CTL_HW;
+	mib[1] = HW_NCPU;
+	len = sizeof(numcpus);
+	if (sysctl(mib, 2, &numcpus, &len, NULL, 0) == 0) {
+		if (numcpus > 1) {
+			_spin_tries = MP_SPIN_TRIES;
+		}
+	} else {
+		count = HOST_BASIC_INFO_COUNT;
+		info = (host_info_t)&basic_info;
+		flavor = HOST_BASIC_INFO;
+		kr = host_info(mach_host_self(), flavor, info, &count);
+		if (kr != KERN_SUCCESS)
+			printf("host_info failed (%d)\n", kr);
+		else {
+			if (basic_info.avail_cpus > 1)
+				_spin_tries = MP_SPIN_TRIES;
+			/* This is a crude test */
+			if (basic_info.cpu_subtype >= CPU_SUBTYPE_POWERPC_7400) 
+				_cpu_has_altivec = 1;
+		}
+	}
+	mib[0] = CTL_HW;
+	mib[1] = HW_VECTORUNIT;
+	len = sizeof(hasvectorunit);
+	if (sysctl(mib, 2, &hasvectorunit, &len, NULL, 0) == 0) {
+		_cpu_has_altivec = hasvectorunit;
+	}
+	mig_init(1);		/* enable multi-threaded mig interfaces */
+	return 0;
+}
+
+int sched_yield(void)
+{
+    swtch_pri(0);
+    return 0;
+}
+
+/* This is the "magic" that gets the initialization routine called when the application starts */
+int (*_cthread_init_routine)(void) = pthread_init;
+
+/* Get a semaphore from the pool, growing it if necessary */
+
+__private_extern__ semaphore_t new_sem_from_pool(void) {
+	kern_return_t res;
+	semaphore_t sem;
+        int i;
+        
+	LOCK(sem_pool_lock);
+	if (sem_pool_current == sem_pool_count) {
+		sem_pool_count += 16;
+		sem_pool = realloc(sem_pool, sem_pool_count * sizeof(semaphore_t));
+		for (i = sem_pool_current; i < sem_pool_count; i++) {
+			PTHREAD_MACH_CALL(semaphore_create(mach_task_self(), &sem_pool[i], SYNC_POLICY_FIFO, 0), res);
+		}
+	}
+	sem = sem_pool[sem_pool_current++];
+	UNLOCK(sem_pool_lock);
+	return sem;
+}
+
+/* Put a semaphore back into the pool */
+__private_extern__ void restore_sem_to_pool(semaphore_t sem) {
+	LOCK(sem_pool_lock);
+	sem_pool[--sem_pool_current] = sem;
+	UNLOCK(sem_pool_lock);
+}
+
+static void sem_pool_reset(void) {
+	LOCK(sem_pool_lock);
+	sem_pool_count = 0;
+	sem_pool_current = 0;
+	sem_pool = NULL; 
+	UNLOCK(sem_pool_lock);
+}
+
+__private_extern__ void _pthread_fork_child(void) {
+	/* Just in case somebody had it locked... */
+	UNLOCK(sem_pool_lock);
+	sem_pool_reset();
+}
+