[apple/xnu.git] / osfmk / kern / syscall_emulation.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and ditribute 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.
 */
/*
 */

#include <mach/error.h>
#include <mach/vm_param.h>
#include <mach/boolean.h>
#include <kern/misc_protos.h>
#include <kern/syscall_emulation.h>
#include <kern/task.h>
#include <kern/kalloc.h>
#include <vm/vm_kern.h>
#include <machine/thread.h>	/* for syscall_emulation_sync */

/*
 * Exported interface
 */

/*
 * WARNING:
 * This code knows that kalloc() allocates memory most efficiently
 * in sizes that are powers of 2, and asks for those sizes.
 */

/*
 * Go from number of entries to size of struct eml_dispatch and back.
 */
#define	base_size	(sizeof(struct eml_dispatch) - sizeof(eml_routine_t))
#define	count_to_size(count) \
	(base_size + sizeof(vm_offset_t) * (count))

#define	size_to_count(size) \
	( ((size) - base_size) / sizeof(vm_offset_t) )

/* Forwards */
kern_return_t
task_set_emulation_vector_internal(
	task_t 			task,
	int			vector_start,
	emulation_vector_t	emulation_vector,
	mach_msg_type_number_t	emulation_vector_count);

/*
 *  eml_init:	initialize user space emulation code
 */
void
eml_init(void)
{
}

/*
 * eml_task_reference() [Exported]
 *
 *	Bumps the reference count on the common emulation
 *	vector.
 */

void
eml_task_reference(
	task_t	task,
	task_t	parent)
{
	register eml_dispatch_t	eml;

	if (parent == TASK_NULL)
	    eml = EML_DISPATCH_NULL;
	else
	    eml = parent->eml_dispatch;

	if (eml != EML_DISPATCH_NULL) {
	    mutex_lock(&eml->lock);
	    eml->ref_count++;
	    mutex_unlock(&eml->lock);
	}
	task->eml_dispatch = eml;
}


/*
 * eml_task_deallocate() [Exported]
 *
 *	Cleans up after the emulation code when a process exits.
 */
 
void
eml_task_deallocate(
	task_t task)
{
	register eml_dispatch_t	eml;

	eml = task->eml_dispatch;
	if (eml != EML_DISPATCH_NULL) {
	    int count;

	    mutex_lock(&eml->lock);
	    count = --eml->ref_count;
	    mutex_unlock(&eml->lock);

	    if (count == 0)
		kfree((vm_offset_t)eml, count_to_size(eml->disp_count));

	    task->eml_dispatch = EML_DISPATCH_NULL;
	}
}

/*
 *   task_set_emulation_vector:  [Server Entry]
 *   set a list of emulated system calls for this task.
 */
kern_return_t
task_set_emulation_vector_internal(
	task_t 			task,
	int			vector_start,
	emulation_vector_t	emulation_vector,
	mach_msg_type_number_t	emulation_vector_count)
{
	eml_dispatch_t	cur_eml, new_eml, old_eml;
	vm_size_t	new_size;
	int		cur_start, cur_end;
	int		new_start, new_end;
	int		vector_end;

	if (task == TASK_NULL)
		return EML_BAD_TASK;

	vector_end = vector_start + (int) emulation_vector_count;

	/*
	 * We try to re-use the existing emulation vetor
	 * if possible.  We can reuse the vector if it
	 * is not shared with another task and if it is
	 * large enough to contain the entries we are
	 * supplying.
	 *
	 * We must grab the lock on the task to check whether
	 * there is an emulation vector.
	 * If the vector is shared or not large enough, we
	 * need to drop the lock and allocate a new emulation
	 * vector.
	 *
	 * While the lock is dropped, the emulation vector
	 * may be released by all other tasks (giving us
	 * exclusive use), or may be enlarged by another
	 * task_set_emulation_vector call.  Therefore,
	 * after allocating the new emulation vector, we
	 * must grab the lock again to check whether we
	 * really need the new vector we just allocated.
	 *
	 * Since an emulation vector cannot be altered
	 * if it is in use by more than one task, the
	 * task lock is sufficient to protect the vector`s
	 * start, count, and contents.  The lock in the
	 * vector protects only the reference count.
	 */

	old_eml = EML_DISPATCH_NULL;	/* vector to discard */
	new_eml = EML_DISPATCH_NULL;	/* new vector */

	for (;;) {
	    /*
	     * Find the current emulation vector.
	     * See whether we can overwrite it.
	     */
	    task_lock(task);
	    cur_eml = task->eml_dispatch;
	    if (cur_eml != EML_DISPATCH_NULL) {
		cur_start = cur_eml->disp_min;
		cur_end   = cur_eml->disp_count + cur_start;

		mutex_lock(&cur_eml->lock);
		if (cur_eml->ref_count == 1 &&
		    cur_start <= vector_start &&
		    cur_end >= vector_end)
		{
		    /*
		     * Can use the existing emulation vector.
		     * Discard any new one we allocated.
		     */
		    mutex_unlock(&cur_eml->lock);
		    old_eml = new_eml;
		    break;
		}

		if (new_eml != EML_DISPATCH_NULL &&
		    new_start <= cur_start &&
		    new_end >= cur_end)
		{
		    /*
		     * A new vector was allocated, and it is large enough
		     * to hold all the entries from the current vector.
		     * Copy the entries to the new emulation vector,
		     * deallocate the current one, and use the new one.
		     */
		    
		    bcopy((char *)&cur_eml->disp_vector[0],
			  (char *)&new_eml->disp_vector[cur_start-new_start],
			  cur_eml->disp_count * sizeof(vm_offset_t));


		    if (--cur_eml->ref_count == 0)
			old_eml = cur_eml;	/* discard old vector */
		    mutex_unlock(&cur_eml->lock);

		    task->eml_dispatch = new_eml;
		    syscall_emulation_sync(task);
		    cur_eml = new_eml;
		    break;
		}
		mutex_unlock(&cur_eml->lock);

		/*
		 * Need a new emulation vector.
		 * Ensure it will hold all the entries from
		 * both the old and new emulation vectors.
		 */
		new_start = vector_start;
		if (new_start > cur_start)
		    new_start = cur_start;
		new_end = vector_end;
		if (new_end < cur_end)
		    new_end = cur_end;
	    }
	    else {
		/*
		 * There is no curren emulation vector.
		 * If a new one was allocated, use it.
		 */
		if (new_eml != EML_DISPATCH_NULL) {
		    task->eml_dispatch = new_eml;
		    cur_eml = new_eml;
		    break;
		}

		/*
		 * Compute the size needed for the new vector.
		 */
		new_start = vector_start;
		new_end = vector_end;
	    }

	    /*
	     * Have no vector (or one that is no longer large enough).
	     * Drop all the locks and allocate a new vector.
	     * Repeat the loop to check whether the old vector was
	     * changed while we didn`t hold the locks.
	     */

	    task_unlock(task);

	    if (new_eml != EML_DISPATCH_NULL)
		kfree((vm_offset_t)new_eml, count_to_size(new_eml->disp_count));

	    new_size = count_to_size(new_end - new_start);
	    new_eml = (eml_dispatch_t) kalloc(new_size);

	    bzero((char *)new_eml, new_size);
	    mutex_init(&new_eml->lock, ETAP_MISC_EMULATE);
	    new_eml->ref_count = 1;
	    new_eml->disp_min   = new_start;
	    new_eml->disp_count = new_end - new_start;

	    continue;
	}

	/*
	 * We have the emulation vector.
	 * Install the new emulation entries.
	 */
	bcopy((char *)&emulation_vector[0],
	      (char *)&cur_eml->disp_vector[vector_start - cur_eml->disp_min],
	      emulation_vector_count * sizeof(vm_offset_t));

	task_unlock(task);

	/*
	 * Discard any old emulation vector we don`t need.
	 */
	if (old_eml)
	    kfree((vm_offset_t) old_eml, count_to_size(old_eml->disp_count));

	return KERN_SUCCESS;
}

/*
 *	task_set_emulation_vector:  [Server Entry]
 *
 *	Set the list of emulated system calls for this task.
 *	The list is out-of-line.
 */
kern_return_t
task_set_emulation_vector(
	task_t 			task,
	int			vector_start,
	emulation_vector_t	emulation_vector,
	mach_msg_type_number_t	emulation_vector_count)
{
	kern_return_t		kr;
	vm_offset_t		emul_vector_addr;

	if (task == TASK_NULL)
	    return EML_BAD_TASK;	/* XXX sb KERN_INVALID_ARGUMENT */

	/*
	 * XXX - barbou@gr.osf.org.
	 * If emulation_vector_count is NULL, discard the emulation
	 * vectors.
	 * We need a way to do that for emulator-less servers started
	 * from a classic server. There seems to be no way to get rid
	 * of or to avoid inheriting the emulation vector !?
	 */
	if (emulation_vector_count == 0) {
		eml_task_deallocate(task);
		return KERN_SUCCESS;
	}


	/*
	 *	The emulation vector is really a vm_map_copy_t.
	 */
	kr = vm_map_copyout(ipc_kernel_map, &emul_vector_addr,
			(vm_map_copy_t) emulation_vector);
	if (kr != KERN_SUCCESS)
	    return kr;

	/*
	 *	Can't fault while we hold locks.
	 */
	kr = vm_map_wire(ipc_kernel_map,
			     trunc_page(emul_vector_addr),
			     round_page(emul_vector_addr +
					emulation_vector_count *
					sizeof(eml_dispatch_t)),
			     VM_PROT_READ|VM_PROT_WRITE, FALSE);
	assert(kr == KERN_SUCCESS);

	/*
	 *	Do the work.
	 */
	kr = task_set_emulation_vector_internal(
			task,
			vector_start,
			(emulation_vector_t) emul_vector_addr,
			emulation_vector_count);
	assert(kr == KERN_SUCCESS);

	/*
	 *	Discard the memory
	 */
	(void) kmem_free(ipc_kernel_map,
			 emul_vector_addr,
			 emulation_vector_count * sizeof(eml_dispatch_t));

	return KERN_SUCCESS;
}

/*
 *	task_get_emulation_vector: [Server Entry]
 *
 *	Get the list of emulated system calls for this task.
 *	List is returned out-of-line.
 */
kern_return_t
task_get_emulation_vector(
	task_t			task,
	int			*vector_start,			/* out */
	emulation_vector_t	*emulation_vector,		/* out */
	mach_msg_type_number_t	*emulation_vector_count)	/* out */
{
	eml_dispatch_t		eml;
	vm_size_t		vector_size, size;
	vm_offset_t		addr;

	if (task == TASK_NULL)
	    return EML_BAD_TASK;

	addr = 0;
	size = 0;

	for(;;) {
	    vm_size_t	size_needed;

	    task_lock(task);
	    eml = task->eml_dispatch;
	    if (eml == EML_DISPATCH_NULL) {
		task_unlock(task);
		if (addr)
		    (void) kmem_free(ipc_kernel_map, addr, size);
		*vector_start = 0;
		*emulation_vector = 0;
		*emulation_vector_count = 0;
		return KERN_SUCCESS;
	    }

	    /*
	     * Do we have the memory we need?
	     */
	    vector_size = eml->disp_count * sizeof(vm_offset_t);

	    size_needed = round_page(vector_size);
	    if (size_needed <= size)
		break;

	    /*
	     * If not, unlock the task and allocate more memory.
	     */
	    task_unlock(task);

	    if (size != 0)
		kmem_free(ipc_kernel_map, addr, size);

	    size = size_needed;
	    if (kmem_alloc(ipc_kernel_map, &addr, size) != KERN_SUCCESS)
		return KERN_RESOURCE_SHORTAGE;
	}

	/*
	 * Copy out the dispatch addresses
	 */
	*vector_start = eml->disp_min;
	*emulation_vector_count = eml->disp_count;
	bcopy((char *)eml->disp_vector,
	      (char *)addr,
	      vector_size);

	/*
	 * Unlock the task and free any memory we did not need
	 */
	task_unlock(task);
    {
	vm_size_t	size_used, size_left;
	vm_map_copy_t	memory;

	/*
	 * Free any unused memory beyond the end of the last page used
	 */
	size_used = round_page(vector_size);
	if (size_used != size)
	    (void) kmem_free(ipc_kernel_map,
			     addr + size_used,
			     size - size_used);

	/*
	 * Zero the remainder of the page being returned.
	 */
	size_left = size_used - vector_size;
	if (size_left > 0)
	    bzero((char *)addr + vector_size, size_left);

	/*
	 * Unwire and make memory into copyin form.
	 */
	(void) vm_map_unwire(ipc_kernel_map, addr, addr + size_used, FALSE);
	(void) vm_map_copyin(ipc_kernel_map, addr, vector_size,
			     TRUE, &memory);

	*emulation_vector = (emulation_vector_t) memory;
    }

	return KERN_SUCCESS;
}

/*
 *   task_set_emulation:  [Server Entry]
 *   set up for user space emulation of syscalls within this task.
 */
kern_return_t
task_set_emulation(
	task_t		task,
	vm_offset_t 	routine_entry_pt,
	int		routine_number)
{
	return task_set_emulation_vector_internal(task, routine_number,
					 &routine_entry_pt, 1);
}
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
43866e37 A	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
	7	*
	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
43866e37 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
1c79356b A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/*
	26	* @OSF_COPYRIGHT@
	27	*/
	28	/*
	29	* Mach Operating System
	30	* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
	31	* All Rights Reserved.
	32	*
	33	* Permission to use, copy, modify and ditribute this software and its
	34	* documentation is hereby granted, provided that both the copyright
	35	* notice and this permission notice appear in all copies of the
	36	* software, derivative works or modified versions, and any portions
	37	* thereof, and that both notices appear in supporting documentation.
	38	*
	39	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	40	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	41	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	42	*
	43	* Carnegie Mellon requests users of this software to return to
	44	*
	45	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	46	* School of Computer Science
	47	* Carnegie Mellon University
	48	* Pittsburgh PA 15213-3890
	49	*
	50	* any improvements or extensions that they make and grant Carnegie Mellon
	51	* the rights to redistribute these changes.
	52	*/
	53	/*
	54	*/
	55
	56	#include <mach/error.h>
	57	#include <mach/vm_param.h>
	58	#include <mach/boolean.h>
	59	#include <kern/misc_protos.h>
	60	#include <kern/syscall_emulation.h>
	61	#include <kern/task.h>
	62	#include <kern/kalloc.h>
	63	#include <vm/vm_kern.h>
	64	#include <machine/thread.h> /* for syscall_emulation_sync */
	65
	66	/*
	67	* Exported interface
	68	*/
	69
	70	/*
	71	* WARNING:
	72	* This code knows that kalloc() allocates memory most efficiently
	73	* in sizes that are powers of 2, and asks for those sizes.
	74	*/
	75
	76	/*
	77	* Go from number of entries to size of struct eml_dispatch and back.
	78	*/
	79	#define base_size (sizeof(struct eml_dispatch) - sizeof(eml_routine_t))
	80	#define count_to_size(count) \
	81	(base_size + sizeof(vm_offset_t) * (count))
	82
	83	#define size_to_count(size) \
	84	( ((size) - base_size) / sizeof(vm_offset_t) )
	85
86	/* Forwards */
87	kern_return_t
88	task_set_emulation_vector_internal(
89	task_t task,
90	int vector_start,
91	emulation_vector_t emulation_vector,
92	mach_msg_type_number_t emulation_vector_count);
93
94	/*
95	* eml_init: initialize user space emulation code
96	*/
97	void
98	eml_init(void)
99	{
100	}
101
102	/*
103	* eml_task_reference() [Exported]
104	*
105	* Bumps the reference count on the common emulation
106	* vector.
107	*/
108
109	void
110	eml_task_reference(
111	task_t task,
112	task_t parent)
113	{
114	register eml_dispatch_t eml;
115
116	if (parent == TASK_NULL)
117	eml = EML_DISPATCH_NULL;
118	else
119	eml = parent->eml_dispatch;
120
121	if (eml != EML_DISPATCH_NULL) {
122	mutex_lock(&eml->lock);
123	eml->ref_count++;
124	mutex_unlock(&eml->lock);
125	}
126	task->eml_dispatch = eml;
127	}
128
129
130	/*
131	* eml_task_deallocate() [Exported]
132	*
133	* Cleans up after the emulation code when a process exits.
134	*/
135
136	void
137	eml_task_deallocate(
138	task_t task)
139	{
140	register eml_dispatch_t eml;
141
142	eml = task->eml_dispatch;
143	if (eml != EML_DISPATCH_NULL) {
144	int count;
145
146	mutex_lock(&eml->lock);
147	count = --eml->ref_count;
148	mutex_unlock(&eml->lock);
149
150	if (count == 0)
151	kfree((vm_offset_t)eml, count_to_size(eml->disp_count));
152
153	task->eml_dispatch = EML_DISPATCH_NULL;
154	}
155	}
156
157	/*
158	* task_set_emulation_vector: [Server Entry]
159	* set a list of emulated system calls for this task.
160	*/
161	kern_return_t
162	task_set_emulation_vector_internal(
163	task_t task,
164	int vector_start,
165	emulation_vector_t emulation_vector,
166	mach_msg_type_number_t emulation_vector_count)
167	{
168	eml_dispatch_t cur_eml, new_eml, old_eml;
169	vm_size_t new_size;
170	int cur_start, cur_end;
171	int new_start, new_end;
172	int vector_end;
173
174	if (task == TASK_NULL)
175	return EML_BAD_TASK;
176
177	vector_end = vector_start + (int) emulation_vector_count;
178
179	/*
180	* We try to re-use the existing emulation vetor
181	* if possible. We can reuse the vector if it
182	* is not shared with another task and if it is
183	* large enough to contain the entries we are
184	* supplying.
185	*
186	* We must grab the lock on the task to check whether
187	* there is an emulation vector.
188	* If the vector is shared or not large enough, we
189	* need to drop the lock and allocate a new emulation
190	* vector.
191	*
192	* While the lock is dropped, the emulation vector
193	* may be released by all other tasks (giving us
194	* exclusive use), or may be enlarged by another
195	* task_set_emulation_vector call. Therefore,
196	* after allocating the new emulation vector, we
197	* must grab the lock again to check whether we
198	* really need the new vector we just allocated.
199	*
200	* Since an emulation vector cannot be altered
201	* if it is in use by more than one task, the
202	* task lock is sufficient to protect the vector`s
203	* start, count, and contents. The lock in the
204	* vector protects only the reference count.
205	*/
206
207	old_eml = EML_DISPATCH_NULL; /* vector to discard */
208	new_eml = EML_DISPATCH_NULL; /* new vector */
209
210	for (;;) {
211	/*
212	* Find the current emulation vector.
213	* See whether we can overwrite it.
214	*/
215	task_lock(task);
216	cur_eml = task->eml_dispatch;
217	if (cur_eml != EML_DISPATCH_NULL) {
218	cur_start = cur_eml->disp_min;
219	cur_end = cur_eml->disp_count + cur_start;
220
221	mutex_lock(&cur_eml->lock);
222	if (cur_eml->ref_count == 1 &&
223	cur_start <= vector_start &&
224	cur_end >= vector_end)
225	{
226	/*
227	* Can use the existing emulation vector.
228	* Discard any new one we allocated.
229	*/
230	mutex_unlock(&cur_eml->lock);
231	old_eml = new_eml;
232	break;
233	}
234
235	if (new_eml != EML_DISPATCH_NULL &&
236	new_start <= cur_start &&
237	new_end >= cur_end)
238	{
239	/*
240	* A new vector was allocated, and it is large enough
241	* to hold all the entries from the current vector.
242	* Copy the entries to the new emulation vector,
243	* deallocate the current one, and use the new one.
244	*/
245
246	bcopy((char *)&cur_eml->disp_vector[0],
247	(char *)&new_eml->disp_vector[cur_start-new_start],
248	cur_eml->disp_count * sizeof(vm_offset_t));
249
250
251	if (--cur_eml->ref_count == 0)
252	old_eml = cur_eml; /* discard old vector */
253	mutex_unlock(&cur_eml->lock);
254
255	task->eml_dispatch = new_eml;
256	syscall_emulation_sync(task);
257	cur_eml = new_eml;
258	break;
259	}
260	mutex_unlock(&cur_eml->lock);
261
262	/*
263	* Need a new emulation vector.
264	* Ensure it will hold all the entries from
265	* both the old and new emulation vectors.
266	*/
267	new_start = vector_start;
268	if (new_start > cur_start)
269	new_start = cur_start;
270	new_end = vector_end;
271	if (new_end < cur_end)
272	new_end = cur_end;
273	}
274	else {
275	/*
276	* There is no curren emulation vector.
277	* If a new one was allocated, use it.
278	*/
279	if (new_eml != EML_DISPATCH_NULL) {
280	task->eml_dispatch = new_eml;
281	cur_eml = new_eml;
282	break;
283	}
284
285	/*
286	* Compute the size needed for the new vector.
287	*/
288	new_start = vector_start;
289	new_end = vector_end;
290	}
291
292	/*
293	* Have no vector (or one that is no longer large enough).
294	* Drop all the locks and allocate a new vector.
295	* Repeat the loop to check whether the old vector was
296	* changed while we didn`t hold the locks.
297	*/
298
299	task_unlock(task);
300
301	if (new_eml != EML_DISPATCH_NULL)
302	kfree((vm_offset_t)new_eml, count_to_size(new_eml->disp_count));
303
304	new_size = count_to_size(new_end - new_start);
305	new_eml = (eml_dispatch_t) kalloc(new_size);
306
307	bzero((char *)new_eml, new_size);
308	mutex_init(&new_eml->lock, ETAP_MISC_EMULATE);
309	new_eml->ref_count = 1;
310	new_eml->disp_min = new_start;
311	new_eml->disp_count = new_end - new_start;
312
313	continue;
314	}
315
316	/*
317	* We have the emulation vector.
318	* Install the new emulation entries.
319	*/
320	bcopy((char *)&emulation_vector[0],
321	(char *)&cur_eml->disp_vector[vector_start - cur_eml->disp_min],
322	emulation_vector_count * sizeof(vm_offset_t));
323
324	task_unlock(task);
325
326	/*
327	* Discard any old emulation vector we don`t need.
328	*/
329	if (old_eml)
330	kfree((vm_offset_t) old_eml, count_to_size(old_eml->disp_count));
331
332	return KERN_SUCCESS;
333	}
334
335	/*
336	* task_set_emulation_vector: [Server Entry]
337	*
338	* Set the list of emulated system calls for this task.
339	* The list is out-of-line.
340	*/
341	kern_return_t
342	task_set_emulation_vector(
343	task_t task,
344	int vector_start,
345	emulation_vector_t emulation_vector,
346	mach_msg_type_number_t emulation_vector_count)
347	{
348	kern_return_t kr;
349	vm_offset_t emul_vector_addr;
350
351	if (task == TASK_NULL)
352	return EML_BAD_TASK; /* XXX sb KERN_INVALID_ARGUMENT */
353
354	/*
355	* XXX - barbou@gr.osf.org.
356	* If emulation_vector_count is NULL, discard the emulation
357	* vectors.
358	* We need a way to do that for emulator-less servers started
359	* from a classic server. There seems to be no way to get rid
360	* of or to avoid inheriting the emulation vector !?
361	*/
362	if (emulation_vector_count == 0) {
363	eml_task_deallocate(task);
364	return KERN_SUCCESS;
365	}
366
367
368	/*
369	* The emulation vector is really a vm_map_copy_t.
370	*/
371	kr = vm_map_copyout(ipc_kernel_map, &emul_vector_addr,
372	(vm_map_copy_t) emulation_vector);
373	if (kr != KERN_SUCCESS)
374	return kr;
375
376	/*
377	* Can't fault while we hold locks.
378	*/
379	kr = vm_map_wire(ipc_kernel_map,
de355530 A	380	trunc_page(emul_vector_addr),
	381	round_page(emul_vector_addr +
	382	emulation_vector_count *
	383	sizeof(eml_dispatch_t)),
1c79356b A	384	VM_PROT_READ\|VM_PROT_WRITE, FALSE);
	385	assert(kr == KERN_SUCCESS);
	386
	387	/*
	388	* Do the work.
	389	*/
	390	kr = task_set_emulation_vector_internal(
	391	task,
	392	vector_start,
	393	(emulation_vector_t) emul_vector_addr,
	394	emulation_vector_count);
	395	assert(kr == KERN_SUCCESS);
	396
	397	/*
	398	* Discard the memory
	399	*/
	400	(void) kmem_free(ipc_kernel_map,
	401	emul_vector_addr,
	402	emulation_vector_count * sizeof(eml_dispatch_t));
	403
	404	return KERN_SUCCESS;
	405	}
	406
	407	/*
	408	* task_get_emulation_vector: [Server Entry]
	409	*
	410	* Get the list of emulated system calls for this task.
	411	* List is returned out-of-line.
	412	*/
	413	kern_return_t
	414	task_get_emulation_vector(
	415	task_t task,
	416	int vector_start, / out */
	417	emulation_vector_t emulation_vector, / out */
	418	mach_msg_type_number_t emulation_vector_count) / out */
	419	{
	420	eml_dispatch_t eml;
	421	vm_size_t vector_size, size;
	422	vm_offset_t addr;
	423
	424	if (task == TASK_NULL)
	425	return EML_BAD_TASK;
	426
	427	addr = 0;
	428	size = 0;
	429
	430	for(;;) {
	431	vm_size_t size_needed;
	432
	433	task_lock(task);
	434	eml = task->eml_dispatch;
	435	if (eml == EML_DISPATCH_NULL) {
	436	task_unlock(task);
	437	if (addr)
	438	(void) kmem_free(ipc_kernel_map, addr, size);
	439	*vector_start = 0;
	440	*emulation_vector = 0;
	441	*emulation_vector_count = 0;
	442	return KERN_SUCCESS;
	443	}
	444
	445	/*
	446	* Do we have the memory we need?
	447	*/
448	vector_size = eml->disp_count * sizeof(vm_offset_t);
449
de355530	450	size_needed = round_page(vector_size);
1c79356b A	451	if (size_needed <= size)
	452	break;
	453
	454	/*
	455	* If not, unlock the task and allocate more memory.
	456	*/
	457	task_unlock(task);
	458
	459	if (size != 0)
	460	kmem_free(ipc_kernel_map, addr, size);
	461
	462	size = size_needed;
	463	if (kmem_alloc(ipc_kernel_map, &addr, size) != KERN_SUCCESS)
	464	return KERN_RESOURCE_SHORTAGE;
	465	}
	466
	467	/*
	468	* Copy out the dispatch addresses
	469	*/
	470	*vector_start = eml->disp_min;
	471	*emulation_vector_count = eml->disp_count;
	472	bcopy((char *)eml->disp_vector,
	473	(char *)addr,
	474	vector_size);
	475
	476	/*
	477	* Unlock the task and free any memory we did not need
	478	*/
	479	task_unlock(task);
	480	{
	481	vm_size_t size_used, size_left;
	482	vm_map_copy_t memory;
	483
	484	/*
	485	* Free any unused memory beyond the end of the last page used
	486	*/
de355530	487	size_used = round_page(vector_size);
1c79356b A	488	if (size_used != size)
	489	(void) kmem_free(ipc_kernel_map,
	490	addr + size_used,
	491	size - size_used);
	492
	493	/*
	494	* Zero the remainder of the page being returned.
	495	*/
	496	size_left = size_used - vector_size;
	497	if (size_left > 0)
	498	bzero((char *)addr + vector_size, size_left);
	499
	500	/*
	501	* Unwire and make memory into copyin form.
	502	*/
	503	(void) vm_map_unwire(ipc_kernel_map, addr, addr + size_used, FALSE);
	504	(void) vm_map_copyin(ipc_kernel_map, addr, vector_size,
	505	TRUE, &memory);
	506
	507	*emulation_vector = (emulation_vector_t) memory;
	508	}
	509
	510	return KERN_SUCCESS;
	511	}
	512
	513	/*
	514	* task_set_emulation: [Server Entry]
	515	* set up for user space emulation of syscalls within this task.
	516	*/
	517	kern_return_t
	518	task_set_emulation(
	519	task_t task,
	520	vm_offset_t routine_entry_pt,
	521	int routine_number)
	522	{
	523	return task_set_emulation_vector_internal(task, routine_number,
	524	&routine_entry_pt, 1);
	525	}
	526
	527
	528
	529