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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 task. 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 | * TODO: Some speedup (hash table?) |
133 | * @return NULL on not found, otherwise pointer to call structure |
133 | * @return NULL on not found, otherwise pointer to call structure |
134 | */ |
134 | */ |
135 | call_t * get_call(__native callid) |
135 | call_t * get_call(__native callid) |
136 | { |
136 | { |
137 | link_t *lst; |
137 | link_t *lst; |
138 | call_t *call, *result = NULL; |
138 | call_t *call, *result = NULL; |
139 | 139 | ||
140 | spinlock_lock(&TASK->answerbox.lock); |
140 | spinlock_lock(&TASK->answerbox.lock); |
141 | for (lst = TASK->answerbox.dispatched_calls.next; |
141 | for (lst = TASK->answerbox.dispatched_calls.next; |
142 | lst != &TASK->answerbox.dispatched_calls; lst = lst->next) { |
142 | lst != &TASK->answerbox.dispatched_calls; lst = lst->next) { |
143 | call = list_get_instance(lst, call_t, link); |
143 | call = list_get_instance(lst, call_t, link); |
144 | if ((__native)call == callid) { |
144 | if ((__native)call == callid) { |
145 | result = call; |
145 | result = call; |
146 | break; |
146 | break; |
147 | } |
147 | } |
148 | } |
148 | } |
149 | spinlock_unlock(&TASK->answerbox.lock); |
149 | spinlock_unlock(&TASK->answerbox.lock); |
150 | return result; |
150 | return result; |
151 | } |
151 | } |
152 | 152 | ||
153 | /** Allocate new phone slot in current TASK structure */ |
153 | /** Allocate new phone slot in current TASK structure */ |
154 | int phone_alloc(void) |
154 | int phone_alloc(void) |
155 | { |
155 | { |
156 | int i; |
156 | int i; |
157 | 157 | ||
158 | spinlock_lock(&TASK->lock); |
158 | spinlock_lock(&TASK->lock); |
159 | 159 | ||
160 | for (i=0; i < IPC_MAX_PHONES; i++) { |
160 | for (i=0; i < IPC_MAX_PHONES; i++) { |
161 | if (TASK->phones[i].state == IPC_PHONE_HUNGUP && \ |
161 | if (TASK->phones[i].state == IPC_PHONE_HUNGUP && \ |
162 | atomic_get(&TASK->phones[i].active_calls) == 0) |
162 | atomic_get(&TASK->phones[i].active_calls) == 0) |
163 | TASK->phones[i].state = IPC_PHONE_FREE; |
163 | TASK->phones[i].state = IPC_PHONE_FREE; |
164 | 164 | ||
165 | if (TASK->phones[i].state == IPC_PHONE_FREE) { |
165 | if (TASK->phones[i].state == IPC_PHONE_FREE) { |
166 | TASK->phones[i].state = IPC_PHONE_CONNECTING; |
166 | TASK->phones[i].state = IPC_PHONE_CONNECTING; |
167 | break; |
167 | break; |
168 | } |
168 | } |
169 | } |
169 | } |
170 | spinlock_unlock(&TASK->lock); |
170 | spinlock_unlock(&TASK->lock); |
171 | 171 | ||
172 | if (i >= IPC_MAX_PHONES) |
172 | if (i >= IPC_MAX_PHONES) |
173 | return -1; |
173 | return -1; |
174 | return i; |
174 | return i; |
175 | } |
175 | } |
176 | 176 | ||
177 | static void phone_deallocp(phone_t *phone) |
177 | static void phone_deallocp(phone_t *phone) |
178 | { |
178 | { |
179 | ASSERT(phone->state == IPC_PHONE_CONNECTING); |
179 | ASSERT(phone->state == IPC_PHONE_CONNECTING); |
180 | 180 | ||
181 | /* atomic operation */ |
181 | /* atomic operation */ |
182 | phone->state = IPC_PHONE_FREE; |
182 | phone->state = IPC_PHONE_FREE; |
183 | } |
183 | } |
184 | 184 | ||
185 | /** Free slot from a disconnected phone |
185 | /** Free slot from a disconnected phone |
186 | * |
186 | * |
187 | * All already sent messages will be correctly processed |
187 | * All already sent messages will be correctly processed |
188 | */ |
188 | */ |
189 | void phone_dealloc(int phoneid) |
189 | void phone_dealloc(int phoneid) |
190 | { |
190 | { |
191 | phone_deallocp(&TASK->phones[phoneid]); |
191 | phone_deallocp(&TASK->phones[phoneid]); |
192 | } |
192 | } |
193 | 193 | ||
194 | /** Connect phone to a given answerbox |
194 | /** Connect phone to a given answerbox |
195 | * |
195 | * |
196 | * @param phoneid The slot that will be connected |
196 | * @param phoneid The slot that will be connected |
197 | * |
197 | * |
198 | * The procedure _enforces_ that the user first marks the phone |
198 | * The procedure _enforces_ that the user first marks the phone |
199 | * busy (e.g. via phone_alloc) and then connects the phone, otherwise |
199 | * busy (e.g. via phone_alloc) and then connects the phone, otherwise |
200 | * race condition may appear. |
200 | * race condition may appear. |
201 | */ |
201 | */ |
202 | void phone_connect(int phoneid, answerbox_t *box) |
202 | void phone_connect(int phoneid, answerbox_t *box) |
203 | { |
203 | { |
204 | phone_t *phone = &TASK->phones[phoneid]; |
204 | phone_t *phone = &TASK->phones[phoneid]; |
205 | 205 | ||
206 | ASSERT(phone->state == IPC_PHONE_CONNECTING); |
206 | ASSERT(phone->state == IPC_PHONE_CONNECTING); |
207 | ipc_phone_connect(phone, box); |
207 | ipc_phone_connect(phone, box); |
208 | } |
208 | } |
209 | 209 |