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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 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_32(emul_vector_addr),
			     round_page_32(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_32(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_32(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	*
e5568f75 A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
43866e37	11	*
e5568f75 A	12	* This Original Code and all software distributed under the License are
e5568f75 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
e5568f75 A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
1c79356b A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/*
	23	* @OSF_COPYRIGHT@
	24	*/
	25	/*
	26	* Mach Operating System
	27	* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
	28	* All Rights Reserved.
	29	*
	30	* Permission to use, copy, modify and ditribute this software and its
	31	* documentation is hereby granted, provided that both the copyright
	32	* notice and this permission notice appear in all copies of the
	33	* software, derivative works or modified versions, and any portions
	34	* thereof, and that both notices appear in supporting documentation.
	35	*
	36	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	37	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	38	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	39	*
	40	* Carnegie Mellon requests users of this software to return to
	41	*
	42	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	43	* School of Computer Science
	44	* Carnegie Mellon University
	45	* Pittsburgh PA 15213-3890
	46	*
	47	* any improvements or extensions that they make and grant Carnegie Mellon
	48	* the rights to redistribute these changes.
	49	*/
	50	/*
	51	*/
	52
	53	#include <mach/error.h>
	54	#include <mach/vm_param.h>
	55	#include <mach/boolean.h>
	56	#include <kern/misc_protos.h>
	57	#include <kern/syscall_emulation.h>
	58	#include <kern/task.h>
	59	#include <kern/kalloc.h>
	60	#include <vm/vm_kern.h>
	61	#include <machine/thread.h> /* for syscall_emulation_sync */
	62
	63	/*
	64	* Exported interface
	65	*/
	66
	67	/*
	68	* WARNING:
	69	* This code knows that kalloc() allocates memory most efficiently
	70	* in sizes that are powers of 2, and asks for those sizes.
	71	*/
	72
	73	/*
	74	* Go from number of entries to size of struct eml_dispatch and back.
	75	*/
	76	#define base_size (sizeof(struct eml_dispatch) - sizeof(eml_routine_t))
	77	#define count_to_size(count) \
	78	(base_size + sizeof(vm_offset_t) * (count))
	79
	80	#define size_to_count(size) \
	81	( ((size) - base_size) / sizeof(vm_offset_t) )
	82
83	/* Forwards */
84	kern_return_t
85	task_set_emulation_vector_internal(
86	task_t task,
87	int vector_start,
88	emulation_vector_t emulation_vector,
89	mach_msg_type_number_t emulation_vector_count);
90
91	/*
92	* eml_init: initialize user space emulation code
93	*/
94	void
95	eml_init(void)
96	{
97	}
98
99	/*
100	* eml_task_reference() [Exported]
101	*
102	* Bumps the reference count on the common emulation
103	* vector.
104	*/
105
106	void
107	eml_task_reference(
108	task_t task,
109	task_t parent)
110	{
111	register eml_dispatch_t eml;
112
113	if (parent == TASK_NULL)
114	eml = EML_DISPATCH_NULL;
115	else
116	eml = parent->eml_dispatch;
117
118	if (eml != EML_DISPATCH_NULL) {
119	mutex_lock(&eml->lock);
120	eml->ref_count++;
121	mutex_unlock(&eml->lock);
122	}
123	task->eml_dispatch = eml;
124	}
125
126
127	/*
128	* eml_task_deallocate() [Exported]
129	*
130	* Cleans up after the emulation code when a process exits.
131	*/
132
133	void
134	eml_task_deallocate(
135	task_t task)
136	{
137	register eml_dispatch_t eml;
138
139	eml = task->eml_dispatch;
140	if (eml != EML_DISPATCH_NULL) {
141	int count;
142
143	mutex_lock(&eml->lock);
144	count = --eml->ref_count;
145	mutex_unlock(&eml->lock);
146
147	if (count == 0)
148	kfree((vm_offset_t)eml, count_to_size(eml->disp_count));
149
150	task->eml_dispatch = EML_DISPATCH_NULL;
151	}
152	}
153
154	/*
155	* task_set_emulation_vector: [Server Entry]
156	* set a list of emulated system calls for this task.
157	*/
158	kern_return_t
159	task_set_emulation_vector_internal(
160	task_t task,
161	int vector_start,
162	emulation_vector_t emulation_vector,
163	mach_msg_type_number_t emulation_vector_count)
164	{
165	eml_dispatch_t cur_eml, new_eml, old_eml;
166	vm_size_t new_size;
167	int cur_start, cur_end;
168	int new_start, new_end;
169	int vector_end;
170
171	if (task == TASK_NULL)
172	return EML_BAD_TASK;
173
174	vector_end = vector_start + (int) emulation_vector_count;
175
176	/*
177	* We try to re-use the existing emulation vetor
178	* if possible. We can reuse the vector if it
179	* is not shared with another task and if it is
180	* large enough to contain the entries we are
181	* supplying.
182	*
183	* We must grab the lock on the task to check whether
184	* there is an emulation vector.
185	* If the vector is shared or not large enough, we
186	* need to drop the lock and allocate a new emulation
187	* vector.
188	*
189	* While the lock is dropped, the emulation vector
190	* may be released by all other tasks (giving us
191	* exclusive use), or may be enlarged by another
192	* task_set_emulation_vector call. Therefore,
193	* after allocating the new emulation vector, we
194	* must grab the lock again to check whether we
195	* really need the new vector we just allocated.
196	*
197	* Since an emulation vector cannot be altered
198	* if it is in use by more than one task, the
199	* task lock is sufficient to protect the vector`s
200	* start, count, and contents. The lock in the
201	* vector protects only the reference count.
202	*/
203
204	old_eml = EML_DISPATCH_NULL; /* vector to discard */
205	new_eml = EML_DISPATCH_NULL; /* new vector */
206
207	for (;;) {
208	/*
209	* Find the current emulation vector.
210	* See whether we can overwrite it.
211	*/
212	task_lock(task);
213	cur_eml = task->eml_dispatch;
214	if (cur_eml != EML_DISPATCH_NULL) {
215	cur_start = cur_eml->disp_min;
216	cur_end = cur_eml->disp_count + cur_start;
217
218	mutex_lock(&cur_eml->lock);
219	if (cur_eml->ref_count == 1 &&
220	cur_start <= vector_start &&
221	cur_end >= vector_end)
222	{
223	/*
224	* Can use the existing emulation vector.
225	* Discard any new one we allocated.
226	*/
227	mutex_unlock(&cur_eml->lock);
228	old_eml = new_eml;
229	break;
230	}
231
232	if (new_eml != EML_DISPATCH_NULL &&
233	new_start <= cur_start &&
234	new_end >= cur_end)
235	{
236	/*
237	* A new vector was allocated, and it is large enough
238	* to hold all the entries from the current vector.
239	* Copy the entries to the new emulation vector,
240	* deallocate the current one, and use the new one.
241	*/
242
243	bcopy((char *)&cur_eml->disp_vector[0],
244	(char *)&new_eml->disp_vector[cur_start-new_start],
245	cur_eml->disp_count * sizeof(vm_offset_t));
246
247
248	if (--cur_eml->ref_count == 0)
249	old_eml = cur_eml; /* discard old vector */
250	mutex_unlock(&cur_eml->lock);
251
252	task->eml_dispatch = new_eml;
253	syscall_emulation_sync(task);
254	cur_eml = new_eml;
255	break;
256	}
257	mutex_unlock(&cur_eml->lock);
258
259	/*
260	* Need a new emulation vector.
261	* Ensure it will hold all the entries from
262	* both the old and new emulation vectors.
263	*/
264	new_start = vector_start;
265	if (new_start > cur_start)
266	new_start = cur_start;
267	new_end = vector_end;
268	if (new_end < cur_end)
269	new_end = cur_end;
270	}
271	else {
272	/*
273	* There is no curren emulation vector.
274	* If a new one was allocated, use it.
275	*/
276	if (new_eml != EML_DISPATCH_NULL) {
277	task->eml_dispatch = new_eml;
278	cur_eml = new_eml;
279	break;
280	}
281
282	/*
283	* Compute the size needed for the new vector.
284	*/
285	new_start = vector_start;
286	new_end = vector_end;
287	}
288
289	/*
290	* Have no vector (or one that is no longer large enough).
291	* Drop all the locks and allocate a new vector.
292	* Repeat the loop to check whether the old vector was
293	* changed while we didn`t hold the locks.
294	*/
295
296	task_unlock(task);
297
298	if (new_eml != EML_DISPATCH_NULL)
299	kfree((vm_offset_t)new_eml, count_to_size(new_eml->disp_count));
300
301	new_size = count_to_size(new_end - new_start);
302	new_eml = (eml_dispatch_t) kalloc(new_size);
303
304	bzero((char *)new_eml, new_size);
305	mutex_init(&new_eml->lock, ETAP_MISC_EMULATE);
306	new_eml->ref_count = 1;
307	new_eml->disp_min = new_start;
308	new_eml->disp_count = new_end - new_start;
309
310	continue;
311	}
312
313	/*
314	* We have the emulation vector.
315	* Install the new emulation entries.
316	*/
317	bcopy((char *)&emulation_vector[0],
318	(char *)&cur_eml->disp_vector[vector_start - cur_eml->disp_min],
319	emulation_vector_count * sizeof(vm_offset_t));
320
321	task_unlock(task);
322
323	/*
324	* Discard any old emulation vector we don`t need.
325	*/
326	if (old_eml)
327	kfree((vm_offset_t) old_eml, count_to_size(old_eml->disp_count));
328
329	return KERN_SUCCESS;
330	}
331
332	/*
333	* task_set_emulation_vector: [Server Entry]
334	*
335	* Set the list of emulated system calls for this task.
336	* The list is out-of-line.
337	*/
338	kern_return_t
339	task_set_emulation_vector(
340	task_t task,
341	int vector_start,
342	emulation_vector_t emulation_vector,
343	mach_msg_type_number_t emulation_vector_count)
344	{
345	kern_return_t kr;
346	vm_offset_t emul_vector_addr;
347
348	if (task == TASK_NULL)
349	return EML_BAD_TASK; /* XXX sb KERN_INVALID_ARGUMENT */
350
351	/*
352	* XXX - barbou@gr.osf.org.
353	* If emulation_vector_count is NULL, discard the emulation
354	* vectors.
355	* We need a way to do that for emulator-less servers started
356	* from a classic server. There seems to be no way to get rid
357	* of or to avoid inheriting the emulation vector !?
358	*/
359	if (emulation_vector_count == 0) {
360	eml_task_deallocate(task);
361	return KERN_SUCCESS;
362	}
363
364
365	/*
366	* The emulation vector is really a vm_map_copy_t.
367	*/
368	kr = vm_map_copyout(ipc_kernel_map, &emul_vector_addr,
369	(vm_map_copy_t) emulation_vector);
370	if (kr != KERN_SUCCESS)
371	return kr;
372
373	/*
374	* Can't fault while we hold locks.
375	*/
376	kr = vm_map_wire(ipc_kernel_map,
55e303ae A	377	trunc_page_32(emul_vector_addr),
	378	round_page_32(emul_vector_addr +
	379	emulation_vector_count *
	380	sizeof(eml_dispatch_t)),
1c79356b A	381	VM_PROT_READ\|VM_PROT_WRITE, FALSE);
	382	assert(kr == KERN_SUCCESS);
	383
	384	/*
	385	* Do the work.
	386	*/
	387	kr = task_set_emulation_vector_internal(
	388	task,
	389	vector_start,
	390	(emulation_vector_t) emul_vector_addr,
	391	emulation_vector_count);
	392	assert(kr == KERN_SUCCESS);
	393
	394	/*
	395	* Discard the memory
	396	*/
	397	(void) kmem_free(ipc_kernel_map,
	398	emul_vector_addr,
	399	emulation_vector_count * sizeof(eml_dispatch_t));
	400
	401	return KERN_SUCCESS;
	402	}
	403
	404	/*
	405	* task_get_emulation_vector: [Server Entry]
	406	*
	407	* Get the list of emulated system calls for this task.
	408	* List is returned out-of-line.
	409	*/
	410	kern_return_t
	411	task_get_emulation_vector(
	412	task_t task,
	413	int vector_start, / out */
	414	emulation_vector_t emulation_vector, / out */
	415	mach_msg_type_number_t emulation_vector_count) / out */
	416	{
	417	eml_dispatch_t eml;
	418	vm_size_t vector_size, size;
	419	vm_offset_t addr;
	420
	421	if (task == TASK_NULL)
	422	return EML_BAD_TASK;
	423
	424	addr = 0;
	425	size = 0;
	426
	427	for(;;) {
	428	vm_size_t size_needed;
	429
	430	task_lock(task);
	431	eml = task->eml_dispatch;
	432	if (eml == EML_DISPATCH_NULL) {
	433	task_unlock(task);
	434	if (addr)
	435	(void) kmem_free(ipc_kernel_map, addr, size);
	436	*vector_start = 0;
	437	*emulation_vector = 0;
	438	*emulation_vector_count = 0;
	439	return KERN_SUCCESS;
	440	}
	441
	442	/*
	443	* Do we have the memory we need?
	444	*/
445	vector_size = eml->disp_count * sizeof(vm_offset_t);
446
55e303ae	447	size_needed = round_page_32(vector_size);
1c79356b A	448	if (size_needed <= size)
	449	break;
	450
	451	/*
	452	* If not, unlock the task and allocate more memory.
	453	*/
	454	task_unlock(task);
	455
	456	if (size != 0)
	457	kmem_free(ipc_kernel_map, addr, size);
	458
	459	size = size_needed;
	460	if (kmem_alloc(ipc_kernel_map, &addr, size) != KERN_SUCCESS)
	461	return KERN_RESOURCE_SHORTAGE;
	462	}
	463
	464	/*
	465	* Copy out the dispatch addresses
	466	*/
	467	*vector_start = eml->disp_min;
	468	*emulation_vector_count = eml->disp_count;
	469	bcopy((char *)eml->disp_vector,
	470	(char *)addr,
	471	vector_size);
	472
	473	/*
	474	* Unlock the task and free any memory we did not need
	475	*/
	476	task_unlock(task);
	477	{
	478	vm_size_t size_used, size_left;
	479	vm_map_copy_t memory;
	480
	481	/*
	482	* Free any unused memory beyond the end of the last page used
	483	*/
55e303ae	484	size_used = round_page_32(vector_size);
1c79356b A	485	if (size_used != size)
	486	(void) kmem_free(ipc_kernel_map,
	487	addr + size_used,
	488	size - size_used);
	489
	490	/*
	491	* Zero the remainder of the page being returned.
	492	*/
	493	size_left = size_used - vector_size;
	494	if (size_left > 0)
	495	bzero((char *)addr + vector_size, size_left);
	496
	497	/*
	498	* Unwire and make memory into copyin form.
	499	*/
	500	(void) vm_map_unwire(ipc_kernel_map, addr, addr + size_used, FALSE);
	501	(void) vm_map_copyin(ipc_kernel_map, addr, vector_size,
	502	TRUE, &memory);
	503
	504	*emulation_vector = (emulation_vector_t) memory;
	505	}
	506
	507	return KERN_SUCCESS;
	508	}
	509
	510	/*
	511	* task_set_emulation: [Server Entry]
	512	* set up for user space emulation of syscalls within this task.
	513	*/
	514	kern_return_t
	515	task_set_emulation(
	516	task_t task,
	517	vm_offset_t routine_entry_pt,
	518	int routine_number)
	519	{
	520	return task_set_emulation_vector_internal(task, routine_number,
	521	&routine_entry_pt, 1);
	522	}
	523
	524
	525
	526