WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/ipc/ipcrsc.c


/*
 * Copyright (C) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/* IPC resources management
 *
 * The goal of this source code is to properly manage IPC resources
 * and allow straight and clean clean-up procedure upon task termination.
 *
 * The pattern of usage of the resources is:
 * - allocate empty phone slot, connect | deallocate slot
 * - disconnect connected phone (some messages might be on the fly)
 * - find phone in slot and send a message using phone
 * - answer message to phone
 * - hangup phone (the caller has hung up)
 * - hangup phone (the answerbox is exiting)
 *
 * Locking strategy
 *
 * - To use a phone, disconnect a phone etc., the phone must be
 *   first locked and then checked that it is connected
 * - To connect an allocated phone it need not be locked (assigning
 *   pointer is atomic on all platforms)
 *
 * - To find an empty phone slot, the TASK must be locked
 * - To answer a message, the answerbox must be locked
 * - The locking of phone and answerbox is done at the ipc_ level.
 *   It is perfectly correct to pass unconnected phone to these functions
 *   and proper reply will be generated.
 *
 * Locking order
 *
 * - first phone, then answerbox
 *   + Easy locking on calls
 *   - Very hard traversing list of phones when disconnecting because
 *     the phones may disconnect during traversal of list of connected phones.
 *     The only possibility is try_lock with restart of list traversal.
 *
 * Destroying is less frequent, this approach is taken.
 *
 * Phone call
 *
 * *** Connect_me_to ***
 * The caller sends IPC_M_CONNECT_ME_TO to an answerbox. The server
 * receives 'phoneid' of the connecting phone as an ARG3. If it answers
 * with RETVAL=0, the phonecall is accepted, otherwise it is refused.
 *
 * *** Connect_to_me ***
 * The caller sends IPC_M_CONNECT_TO_ME, with special
 * The server receives an automatically
 * opened phoneid. If it accepts (RETVAL=0), it can use the phoneid
 * immediately.
 * Possible race condition can arise, when the client receives messages
 * from new connection before getting response for connect_to_me message.
 * Userspace should implement handshake protocol that would control it.
 *
 * Phone hangup
 *
 * *** The caller hangs up (sys_ipc_hangup) ***
 * - The phone is disconnected (no more messages can be sent over this phone),
 *   all in-progress messages are correctly handled. The anwerbox receives
 *   IPC_M_PHONE_HUNGUP call from the phone that hung up. When all async
 *   calls are answered, the phone is deallocated.
 *
 * *** The answerbox hangs up (ipc_answer(EHANGUP))
 * - The phone is disconnected. EHANGUP response code is sent
 *   to the calling process. All new calls through this phone
 *   get a EHUNGUP error code, the task is expected to
 *   send an sys_ipc_hangup after cleaning up it's internal structures.
 *
 * Call forwarding
 *
 * The call can be forwarded, so that the answer to call is passed directly
 * to the original sender. However, this poses special problems regarding
 * routing of hangup messages.
 *
 * sys_ipc_hangup -> IPC_M_PHONE_HUNGUP
 * - this message CANNOT be forwarded
 *
 * EHANGUP during forward
 * - The *forwarding* phone will be closed, EFORWARD is sent to receiver.
 *
 * EHANGUP, ENOENT during forward
 * - EFORWARD is sent to the receiver, ipc_forward returns error code EFORWARD
 *
 * Cleanup strategy
 *
 * 1) Disconnect all our phones ('ipc_phone_hangup').
 *
 * 2) Disconnect all phones connected to answerbox.
 *
 * 3) Answer all messages in 'calls' and 'dispatched_calls' queues with
 *    appropriate error code (EHANGUP, EFORWARD).
 *
 * 4) Wait for all async answers to arrive and dispose of them.
 *
 */
 
#include <synch/spinlock.h>
#include <ipc/ipc.h>
#include <arch.h>
#include <proc/task.h>
#include <ipc/ipcrsc.h>
#include <debug.h>
 
/** Find call_t * in call table according to callid
 *
 * TODO: Some speedup (hash table?)
 * @return NULL on not found, otherwise pointer to call structure
 */
call_t * get_call(__native callid)
{
    link_t *lst;
    call_t *call, *result = NULL;
 
    spinlock_lock(&TASK->answerbox.lock);
    for (lst = TASK->answerbox.dispatched_calls.next;
         lst != &TASK->answerbox.dispatched_calls; lst = lst->next) {
        call = list_get_instance(lst, call_t, list);
        if ((__native)call == callid) {
            result = call;
            break;
        }
    }
    spinlock_unlock(&TASK->answerbox.lock);
    return result;
}
 
/** Allocate new phone slot in current TASK structure */
int phone_alloc(void)
{
    int i;
 
    spinlock_lock(&TASK->lock);
   
    for (i=0; i < IPC_MAX_PHONES; i++) {
        if (TASK->phones[i].busy==IPC_BUSY_FREE && !atomic_get(&TASK->phones[i].active_calls)) {
            TASK->phones[i].busy = IPC_BUSY_CONNECTING;
            break;
        }
    }
    spinlock_unlock(&TASK->lock);
 
    if (i >= IPC_MAX_PHONES)
        return -1;
    return i;
}
 
static void phone_deallocp(phone_t *phone)
{
    ASSERT(phone->busy == IPC_BUSY_CONNECTING);
    ASSERT(! phone->callee);
   
    /* atomic operation */
    phone->busy = IPC_BUSY_FREE;
}
 
/** Free slot from a disconnected phone
 *
 * All already sent messages will be correctly processed
 */
void phone_dealloc(int phoneid)
{
    phone_deallocp(&TASK->phones[phoneid]);
}
 
/** Connect phone to a given answerbox
 *
 * @param phoneid The slot that will be connected
 *
 * The procedure _enforces_ that the user first marks the phone
 * busy (e.g. via phone_alloc) and then connects the phone, otherwise
 * race condition may appear.
 */
void phone_connect(int phoneid, answerbox_t *box)
{
    phone_t *phone = &TASK->phones[phoneid];
   
    ASSERT(phone->busy == IPC_BUSY_CONNECTING);
    ipc_phone_connect(phone, box);
}
 

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/ipc/ipcrsc.c – Rev 1090 → 1141

Rev 1090		Rev 1141
1	/*	1	/*
2	* Copyright (C) 2006 Ondrej Palkovsky	2	* Copyright (C) 2006 Ondrej Palkovsky
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/* IPC resources management	29	/* IPC resources management
30	*	30	*
31	* The goal of this source code is to properly manage IPC resources	31	* The goal of this source code is to properly manage IPC resources
32	* and allow straight and clean clean-up procedure upon task termination.	32	* and allow straight and clean clean-up procedure upon task termination.
33	*	33	*
34	* The pattern of usage of the resources is:	34	* The pattern of usage of the resources is:
35	* - allocate empty phone slot, connect \| deallocate slot	35	* - allocate empty phone slot, connect \| deallocate slot
36	* - disconnect connected phone (some messages might be on the fly)	36	* - disconnect connected phone (some messages might be on the fly)
37	* - find phone in slot and send a message using phone	37	* - find phone in slot and send a message using phone
38	* - answer message to phone	38	* - answer message to phone
39	* - hangup phone (the caller has hung up)	39	* - hangup phone (the caller has hung up)
40	* - hangup phone (the answerbox is exiting)	40	* - hangup phone (the answerbox is exiting)
41	*	41	*
42	* Locking strategy	42	* Locking strategy
43	*	43	*
44	* - To use a phone, disconnect a phone etc., the phone must be	44	* - To use a phone, disconnect a phone etc., the phone must be
45	* first locked and then checked that it is connected	45	* first locked and then checked that it is connected
46	* - To connect an allocated phone it need not be locked (assigning	46	* - To connect an allocated phone it need not be locked (assigning
47	* pointer is atomic on all platforms)	47	* pointer is atomic on all platforms)
48	*	48	*
49	* - To find an empty phone slot, the TASK must be locked	49	* - To find an empty phone slot, the TASK must be locked
50	* - To answer a message, the answerbox must be locked	50	* - To answer a message, the answerbox must be locked
51	* - The locking of phone and answerbox is done at the ipc_ level.	51	* - The locking of phone and answerbox is done at the ipc_ level.
52	* It is perfectly correct to pass unconnected phone to these functions	52	* It is perfectly correct to pass unconnected phone to these functions
53	* and proper reply will be generated.	53	* and proper reply will be generated.
54	*	54	*
55	* Locking order	55	* Locking order
56	*	56	*
57	* - first phone, then answerbox	57	* - first phone, then answerbox
58	* + Easy locking on calls	58	* + Easy locking on calls
59	* - Very hard traversing list of phones when disconnecting because	59	* - Very hard traversing list of phones when disconnecting because
60	* the phones may disconnect during traversal of list of connected phones.	60	* the phones may disconnect during traversal of list of connected phones.
61	* The only possibility is try_lock with restart of list traversal.	61	* The only possibility is try_lock with restart of list traversal.
62	*	62	*
63	* Destroying is less frequent, this approach is taken.	63	* Destroying is less frequent, this approach is taken.
64	*	64	*
65	* Phone call	65	* Phone call
66	*	66	*
67	* * Connect_me_to *	67	* * Connect_me_to *
68	* The caller sends IPC_M_CONNECT_ME_TO to an answerbox. The server	68	* The caller sends IPC_M_CONNECT_ME_TO to an answerbox. The server
69	* receives 'phoneid' of the connecting phone as an ARG3. If it answers	69	* receives 'phoneid' of the connecting phone as an ARG3. If it answers
70	* with RETVAL=0, the phonecall is accepted, otherwise it is refused.	70	* with RETVAL=0, the phonecall is accepted, otherwise it is refused.
71	*	71	*
72	* * Connect_to_me *	72	* * Connect_to_me *
73	* The caller sends IPC_M_CONNECT_TO_ME, with special	73	* The caller sends IPC_M_CONNECT_TO_ME, with special
74	* The server receives an automatically	74	* The server receives an automatically
75	* opened phoneid. If it accepts (RETVAL=0), it can use the phoneid	75	* opened phoneid. If it accepts (RETVAL=0), it can use the phoneid
76	* immediately.	76	* immediately.
77	* Possible race condition can arise, when the client receives messages	77	* Possible race condition can arise, when the client receives messages
78	* from new connection before getting response for connect_to_me message.	78	* from new connection before getting response for connect_to_me message.
79	* Userspace should implement handshake protocol that would control it.	79	* Userspace should implement handshake protocol that would control it.
80	*	80	*
81	* Phone hangup	81	* Phone hangup
82	*	82	*
83	* * The caller hangs up (sys_ipc_hangup) *	83	* * The caller hangs up (sys_ipc_hangup) *
84	* - The phone is disconnected (no more messages can be sent over this phone),	84	* - The phone is disconnected (no more messages can be sent over this phone),
85	* all in-progress messages are correctly handled. The anwerbox receives	85	* all in-progress messages are correctly handled. The anwerbox receives
86	* IPC_M_PHONE_HUNGUP call from the phone that hung up. When all async	86	* IPC_M_PHONE_HUNGUP call from the phone that hung up. When all async
87	* calls are answered, the phone is deallocated.	87	* calls are answered, the phone is deallocated.
88	*	88	*
89	* *** The answerbox hangs up (ipc_answer(EHANGUP))	89	* *** The answerbox hangs up (ipc_answer(EHANGUP))
90	* - The phone is disconnected. EHANGUP response code is sent	90	* - The phone is disconnected. EHANGUP response code is sent
91	* to the calling process. All new calls through this phone	91	* to the calling process. All new calls through this phone
92	* get a EHUNGUP error code, the task is expected to	92	* get a EHUNGUP error code, the task is expected to
93	* send an sys_ipc_hangup after cleaning up it's internal structures.	93	* send an sys_ipc_hangup after cleaning up it's internal structures.
94	*	94	*
95	* Call forwarding	95	* Call forwarding
96	*	96	*
97	* The call can be forwarded, so that the answer to call is passed directly	97	* The call can be forwarded, so that the answer to call is passed directly
98	* to the original sender. However, this poses special problems regarding	98	* to the original sender. However, this poses special problems regarding
99	* routing of hangup messages.	99	* routing of hangup messages.
100	*	100	*
101	* sys_ipc_hangup -> IPC_M_PHONE_HUNGUP	101	* sys_ipc_hangup -> IPC_M_PHONE_HUNGUP
102	* - this message CANNOT be forwarded	102	* - this message CANNOT be forwarded
103	*	103	*
104	* EHANGUP during forward	104	* EHANGUP during forward
105	* - The forwarding phone will be closed, EFORWARD is sent to receiver.	105	* - The forwarding phone will be closed, EFORWARD is sent to receiver.
106	*	106	*
107	* EHANGUP, ENOENT during forward	107	* EHANGUP, ENOENT during forward
108	* - EFORWARD is sent to the receiver, ipc_forward returns error code EFORWARD	108	* - EFORWARD is sent to the receiver, ipc_forward returns error code EFORWARD
109	*	109	*
110	* Cleanup strategy	110	* Cleanup strategy
111	*	111	*
112	* 1) Disconnect all our phones ('ipc_phone_hangup').	112	* 1) Disconnect all our phones ('ipc_phone_hangup').
113	*	113	*
114	* 2) Disconnect all phones connected to answerbox.	114	* 2) Disconnect all phones connected to answerbox.
115	*	115	*
116	* 3) Answer all messages in 'calls' and 'dispatched_calls' queues with	116	* 3) Answer all messages in 'calls' and 'dispatched_calls' queues with
117	* appropriate error code (EHANGUP, EFORWARD).	117	* appropriate error code (EHANGUP, EFORWARD).
118	*	118	*
119	* 4) Wait for all async answers to arrive and dispose of them.	119	* 4) Wait for all async answers to arrive and dispose of them.
120	*	120	*
121	*/	121	*/
122		122
123	#include <synch/spinlock.h>	123	#include <synch/spinlock.h>
124	#include <ipc/ipc.h>	124	#include <ipc/ipc.h>
125	#include <arch.h>	125	#include <arch.h>
126	#include <proc/task.h>	126	#include <proc/task.h>
127	#include <ipc/ipcrsc.h>	127	#include <ipc/ipcrsc.h>
128	#include <debug.h>	128	#include <debug.h>
129		129
130	/** Find call_t * in call table according to callid	130	/** Find call_t * in call table according to callid
131	*	131	*
-		132	* TODO: Some speedup (hash table?)
132	* @return NULL on not found, otherwise pointer to call structure	133	* @return NULL on not found, otherwise pointer to call structure
133	*/	134	*/
134	call_t * get_call(__native callid)	135	call_t * get_call(__native callid)
135	{	136	{
-		137	link_t *lst;
-		138	call_t call, result = NULL;
-		139
-		140	spinlock_lock(&TASK->answerbox.lock);
136	/* TODO: Traverse list of dispatched calls and find one */	141	for (lst = TASK->answerbox.dispatched_calls.next;
137	/* TODO: locking of call, ripping it from dispatched calls etc. */	142	lst != &TASK->answerbox.dispatched_calls; lst = lst->next) {
-		143	call = list_get_instance(lst, call_t, list);
-		144	if ((__native)call == callid) {
138	return (call_t *) callid;	145	result = call;
-		146	break;
-		147	}
-		148	}
-		149	spinlock_unlock(&TASK->answerbox.lock);
-		150	return result;
139	}	151	}
140		152
141	/** Allocate new phone slot in current TASK structure */	153	/** Allocate new phone slot in current TASK structure */
142	int phone_alloc(void)	154	int phone_alloc(void)
143	{	155	{
144	int i;	156	int i;
145		157
146	spinlock_lock(&TASK->lock);	158	spinlock_lock(&TASK->lock);
147		159
148	for (i=0; i < IPC_MAX_PHONES; i++) {	160	for (i=0; i < IPC_MAX_PHONES; i++) {
149	if (TASK->phones[i].busy==IPC_BUSY_FREE && !atomic_get(&TASK->phones[i].active_calls)) {	161	if (TASK->phones[i].busy==IPC_BUSY_FREE && !atomic_get(&TASK->phones[i].active_calls)) {
150	TASK->phones[i].busy = IPC_BUSY_CONNECTING;	162	TASK->phones[i].busy = IPC_BUSY_CONNECTING;
151	break;	163	break;
152	}	164	}
153	}	165	}
154	spinlock_unlock(&TASK->lock);	166	spinlock_unlock(&TASK->lock);
155		167
156	if (i >= IPC_MAX_PHONES)	168	if (i >= IPC_MAX_PHONES)
157	return -1;	169	return -1;
158	return i;	170	return i;
159	}	171	}
160		172
161	static void phone_deallocp(phone_t *phone)	173	static void phone_deallocp(phone_t *phone)
162	{	174	{
163	ASSERT(phone->busy == IPC_BUSY_CONNECTING);	175	ASSERT(phone->busy == IPC_BUSY_CONNECTING);
164	ASSERT(! phone->callee);	176	ASSERT(! phone->callee);
165		177
166	/* atomic operation */	178	/* atomic operation */
167	phone->busy = IPC_BUSY_FREE;	179	phone->busy = IPC_BUSY_FREE;
168	}	180	}
169		181
170	/** Free slot from a disconnected phone	182	/** Free slot from a disconnected phone
171	*	183	*
172	* All already sent messages will be correctly processed	184	* All already sent messages will be correctly processed
173	*/	185	*/
174	void phone_dealloc(int phoneid)	186	void phone_dealloc(int phoneid)
175	{	187	{
176	phone_deallocp(&TASK->phones[phoneid]);	188	phone_deallocp(&TASK->phones[phoneid]);
177	}	189	}
178		190
179	/** Connect phone to a given answerbox	191	/** Connect phone to a given answerbox
180	*	192	*
181	* @param phoneid The slot that will be connected	193	* @param phoneid The slot that will be connected
182	*	194	*
183	* The procedure _enforces_ that the user first marks the phone	195	* The procedure _enforces_ that the user first marks the phone
184	* busy (e.g. via phone_alloc) and then connects the phone, otherwise	196	* busy (e.g. via phone_alloc) and then connects the phone, otherwise
185	* race condition may appear.	197	* race condition may appear.
186	*/	198	*/
187	void phone_connect(int phoneid, answerbox_t *box)	199	void phone_connect(int phoneid, answerbox_t *box)
188	{	200	{
189	phone_t *phone = &TASK->phones[phoneid];	201	phone_t *phone = &TASK->phones[phoneid];
190		202
191	ASSERT(phone->busy == IPC_BUSY_CONNECTING);	203	ASSERT(phone->busy == IPC_BUSY_CONNECTING);
192	ipc_phone_connect(phone, box);	204	ipc_phone_connect(phone, box);
193	}	205	}
194		206