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1351 palkovsky 1
/*
2
 * Copyright (C) 2006 Ondrej Palkovsky
3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
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
15
 *   derived from this software without specific prior written permission.
16
 *
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
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
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
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
1392 palkovsky 29
/**
30
 * Asynchronous library
31
 *
32
 * The aim of this library is facilitating writing programs utilizing
33
 * the asynchronous nature of Helenos IPC, yet using a normal way
34
 * of programming.
35
 *
36
 * You should be able to write very simple multithreaded programs,
37
 * the async framework will automatically take care of most synchronization
38
 * problems.
39
 *
40
 * Default semantics:
41
 * - send() - send asynchronously. If the kernel refuses to send more
42
 *            messages, [ try to get responses from kernel, if nothing
43
 *            found, might try synchronous ]
44
 *
45
 * Example of use:
46
 *
47
 * 1) Multithreaded client application
48
 *  create_thread(thread1);
49
 *  create_thread(thread2);
50
 *  ...
51
 *  
52
 *  thread1() {
53
 *        conn = ipc_connect_me_to();
54
 *        c1 = send(conn);
55
 *        c2 = send(conn);
56
 *        wait_for(c1);
57
 *        wait_for(c2);
58
 *  }
59
 *
60
 *
61
 * 2) Multithreaded server application
62
 * main() {
1407 palkovsky 63
 *      async_manager();
1392 palkovsky 64
 * }
65
 *
66
 *
1407 palkovsky 67
 * client_connection(icallid, *icall) {
68
 *       if (want_refuse) {
69
 *           ipc_answer_fast(icallid, ELIMIT, 0, 0);
70
 *           return;
71
 *       }
72
 *       ipc_answer_fast(icallid, 0, 0, 0);
1392 palkovsky 73
 *
1407 palkovsky 74
 *       callid = async_get_call(&call);
75
 *       handle(callid, call);
76
 *       ipc_answer_fast(callid, 1,2,3);
77
 *
78
 *       callid = async_get_call(&call);
1392 palkovsky 79
 *       ....
80
 * }
1404 palkovsky 81
 *
1405 decky 82
 * TODO: Detaching/joining dead psthreads?
1392 palkovsky 83
 */
84
#include <futex.h>
85
#include <async.h>
86
#include <psthread.h>
87
#include <stdio.h>
88
#include <libadt/hash_table.h>
89
#include <libadt/list.h>
90
#include <ipc/ipc.h>
91
#include <assert.h>
92
#include <errno.h>
93
 
1427 palkovsky 94
static atomic_t async_futex = FUTEX_INITIALIZER;
1392 palkovsky 95
static hash_table_t conn_hash_table;
96
 
97
typedef struct {
1427 palkovsky 98
    pstid_t ptid;                /**< Thread waiting for this message */
99
    int active;                  /**< If this thread is currently active */
100
    int done;                    /**< If reply was received */
101
    ipc_call_t *dataptr;         /**< Pointer where the answer data
102
                      *   should be stored */
103
    ipcarg_t retval;
104
} amsg_t;
105
 
106
typedef struct {
1392 palkovsky 107
    link_t link;
108
    ipc_callid_t callid;
109
    ipc_call_t call;
110
} msg_t;
111
 
112
typedef struct {
113
    link_t link;
114
    ipcarg_t in_phone_hash;     /**< Incoming phone hash. */
115
    link_t msg_queue;              /**< Messages that should be delivered to this thread */
116
    pstid_t ptid;                /**< Thread associated with this connection */
117
    int active;                     /**< If this thread is currently active */
118
    /* Structures for connection opening packet */
119
    ipc_callid_t callid;
120
    ipc_call_t call;
1407 palkovsky 121
    void (*cthread)(ipc_callid_t,ipc_call_t *);
1392 palkovsky 122
} connection_t;
123
 
124
__thread connection_t *PS_connection;
125
 
126
/* Hash table functions */
1404 palkovsky 127
#define CONN_HASH_TABLE_CHAINS  32
1392 palkovsky 128
 
129
static hash_index_t conn_hash(unsigned long *key)
1351 palkovsky 130
{
1392 palkovsky 131
    assert(key);
1404 palkovsky 132
    return ((*key) >> 4) % CONN_HASH_TABLE_CHAINS;
1351 palkovsky 133
}
134
 
1392 palkovsky 135
static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item)
1351 palkovsky 136
{
1392 palkovsky 137
    connection_t *hs;
138
 
139
    hs = hash_table_get_instance(item, connection_t, link);
140
 
141
    return key[0] == hs->in_phone_hash;
1351 palkovsky 142
}
143
 
1392 palkovsky 144
static void conn_remove(link_t *item)
1351 palkovsky 145
{
1392 palkovsky 146
    free(hash_table_get_instance(item, connection_t, link));
1351 palkovsky 147
}
148
 
1392 palkovsky 149
 
150
/** Operations for NS hash table. */
151
static hash_table_operations_t conn_hash_table_ops = {
152
    .hash = conn_hash,
153
    .compare = conn_compare,
154
    .remove_callback = conn_remove
155
};
156
 
1427 palkovsky 157
/*************************************************/
158
 
1392 palkovsky 159
/** Try to route a call to an appropriate connection thread
160
 *
161
 */
162
static int route_call(ipc_callid_t callid, ipc_call_t *call)
1351 palkovsky 163
{
1392 palkovsky 164
    connection_t *conn;
165
    msg_t *msg;
166
    link_t *hlp;
167
    unsigned long key;
168
 
1427 palkovsky 169
    futex_down(&async_futex);
1392 palkovsky 170
 
171
    key = call->in_phone_hash;
172
    hlp = hash_table_find(&conn_hash_table, &key);
173
    if (!hlp) {
1427 palkovsky 174
        futex_up(&async_futex);
1392 palkovsky 175
        return 0;
1351 palkovsky 176
    }
1392 palkovsky 177
    conn = hash_table_get_instance(hlp, connection_t, link);
1351 palkovsky 178
 
1392 palkovsky 179
    msg = malloc(sizeof(*msg));
180
    msg->callid = callid;
181
    msg->call = *call;
182
    list_append(&msg->link, &conn->msg_queue);
183
 
184
    if (!conn->active) {
185
        conn->active = 1;
186
        psthread_add_ready(conn->ptid);
187
    }
1351 palkovsky 188
 
1427 palkovsky 189
    futex_up(&async_futex);
1392 palkovsky 190
 
191
    return 1;
192
}
193
 
1404 palkovsky 194
/** Return new incoming message for current(thread-local) connection */
1392 palkovsky 195
ipc_callid_t async_get_call(ipc_call_t *call)
196
{
197
    msg_t *msg;
198
    ipc_callid_t callid;
199
    connection_t *conn;
200
 
1427 palkovsky 201
    futex_down(&async_futex);
1392 palkovsky 202
 
203
    conn = PS_connection;
204
    /* If nothing in queue, wait until something appears */
205
    if (list_empty(&conn->msg_queue)) {
206
        conn->active = 0;
207
        psthread_schedule_next_adv(PS_TO_MANAGER);
1351 palkovsky 208
    }
209
 
1392 palkovsky 210
    msg = list_get_instance(conn->msg_queue.next, msg_t, link);
211
    list_remove(&msg->link);
212
    callid = msg->callid;
213
    *call = msg->call;
214
    free(msg);
215
 
1427 palkovsky 216
    futex_up(&async_futex);
1392 palkovsky 217
    return callid;
1351 palkovsky 218
}
219
 
1404 palkovsky 220
/** Thread function that gets created on new connection
221
 *
222
 * This function is defined as a weak symbol - to be redefined in
223
 * user code.
224
 */
1392 palkovsky 225
void client_connection(ipc_callid_t callid, ipc_call_t *call)
226
{
1404 palkovsky 227
    ipc_answer_fast(callid, ENOENT, 0, 0);
1392 palkovsky 228
}
1351 palkovsky 229
 
1404 palkovsky 230
/** Wrapper for client connection thread
231
 *
232
 * When new connection arrives, thread with this function is created.
233
 * It calls client_connection and does final cleanup.
234
 *
235
 * @parameter arg Connection structure pointer
236
 */
1392 palkovsky 237
static int connection_thread(void  *arg)
1351 palkovsky 238
{
1404 palkovsky 239
    unsigned long key;
240
    msg_t *msg;
1408 palkovsky 241
    connection_t *conn;
1404 palkovsky 242
 
1392 palkovsky 243
    /* Setup thread local connection pointer */
244
    PS_connection = (connection_t *)arg;
1408 palkovsky 245
    conn = PS_connection;
246
    conn->cthread(conn->callid, &conn->call);
1392 palkovsky 247
 
1404 palkovsky 248
    /* Remove myself from connection hash table */
1427 palkovsky 249
    futex_down(&async_futex);
1408 palkovsky 250
    key = conn->in_phone_hash;
1404 palkovsky 251
    hash_table_remove(&conn_hash_table, &key, 1);
1427 palkovsky 252
    futex_up(&async_futex);
1404 palkovsky 253
    /* Answer all remaining messages with ehangup */
1408 palkovsky 254
    while (!list_empty(&conn->msg_queue)) {
255
        msg = list_get_instance(conn->msg_queue.next, msg_t, link);
1404 palkovsky 256
        list_remove(&msg->link);
257
        ipc_answer_fast(msg->callid, EHANGUP, 0, 0);
258
        free(msg);
259
    }
1351 palkovsky 260
}
1392 palkovsky 261
 
262
/** Create new thread for a new connection
263
 *
264
 * Creates new thread for connection, fills in connection
265
 * structures and inserts it into the hash table, so that
266
 * later we can easily do routing of messages to particular
267
 * threads.
1407 palkovsky 268
 *
269
 * @param callid Callid of the IPC_M_CONNECT_ME_TO packet
270
 * @param call Call data of the opening packet
271
 * @param cthread Thread function that should be called upon
272
 *                opening the connection
273
 * @return New thread id
1392 palkovsky 274
 */
1407 palkovsky 275
pstid_t async_new_connection(ipc_callid_t callid, ipc_call_t *call,
276
                 void (*cthread)(ipc_callid_t,ipc_call_t *))
1392 palkovsky 277
{
278
    pstid_t ptid;
279
    connection_t *conn;
280
    unsigned long key;
281
 
282
    conn = malloc(sizeof(*conn));
283
    if (!conn) {
284
        ipc_answer_fast(callid, ENOMEM, 0, 0);
1407 palkovsky 285
        return NULL;
1392 palkovsky 286
    }
287
    conn->in_phone_hash = IPC_GET_ARG3(*call);
288
    list_initialize(&conn->msg_queue);
289
    conn->ptid = psthread_create(connection_thread, conn);
290
    conn->callid = callid;
291
    conn->call = *call;
292
    conn->active = 1; /* We will activate it asap */
1407 palkovsky 293
    conn->cthread = cthread;
1392 palkovsky 294
    list_initialize(&conn->link);
295
    if (!conn->ptid) {
296
        free(conn);
297
        ipc_answer_fast(callid, ENOMEM, 0, 0);
1407 palkovsky 298
        return NULL;
1392 palkovsky 299
    }
300
    key = conn->in_phone_hash;
1427 palkovsky 301
    futex_down(&async_futex);
1392 palkovsky 302
    /* Add connection to hash table */
303
    hash_table_insert(&conn_hash_table, &key, &conn->link);
1427 palkovsky 304
    futex_up(&async_futex);
1392 palkovsky 305
 
306
    psthread_add_ready(conn->ptid);
1407 palkovsky 307
 
308
    return conn->ptid;
1392 palkovsky 309
}
310
 
1427 palkovsky 311
/** Handle call that was received */
1392 palkovsky 312
static void handle_call(ipc_callid_t callid, ipc_call_t *call)
313
{
314
    if (route_call(callid, call))
315
        return;
316
 
317
    switch (IPC_GET_METHOD(*call)) {
318
    case IPC_M_INTERRUPT:
319
        break;
320
    case IPC_M_CONNECT_ME_TO:
321
        /* Open new connection with thread etc. */
1407 palkovsky 322
        async_new_connection(callid, call, client_connection);
1392 palkovsky 323
        break;
324
    default:
325
        ipc_answer_fast(callid, EHANGUP, 0, 0);
326
    }
327
}
328
 
329
/** Endless loop dispatching incoming calls and answers */
330
int async_manager()
331
{
332
    ipc_call_t call;
333
    ipc_callid_t callid;
334
 
335
    while (1) {
336
        if (psthread_schedule_next_adv(PS_FROM_MANAGER)) {
1427 palkovsky 337
            futex_up(&async_futex); /* async_futex is always held
1392 palkovsky 338
                        * when entering manager thread
339
                        */
340
            continue;
341
        }
342
        callid = ipc_wait_cycle(&call,SYNCH_NO_TIMEOUT,SYNCH_BLOCKING);
343
 
344
        if (callid & IPC_CALLID_ANSWERED)
345
            continue;
1427 palkovsky 346
 
1392 palkovsky 347
        handle_call(callid, &call);
348
    }
349
}
350
 
1404 palkovsky 351
/** Function to start async_manager as a standalone thread
352
 *
353
 * When more kernel threads are used, one async manager should
354
 * exist per thread. The particular implementation may change,
355
 * currently one async_manager is started automatically per kernel
356
 * thread except main thread.
357
 */
1392 palkovsky 358
static int async_manager_thread(void *arg)
359
{
1427 palkovsky 360
    futex_up(&async_futex); /* async_futex is always locked when entering
1392 palkovsky 361
                * manager */
362
    async_manager();
363
}
364
 
365
/** Add one manager to manager list */
366
void async_create_manager(void)
367
{
368
    pstid_t ptid;
369
 
370
    ptid = psthread_create(async_manager_thread, NULL);
371
    psthread_add_manager(ptid);
372
}
373
 
374
/** Remove one manager from manager list */
375
void async_destroy_manager(void)
376
{
377
    psthread_remove_manager();
378
}
379
 
380
/** Initialize internal structures needed for async manager */
381
int _async_init(void)
382
{
1404 palkovsky 383
    if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1, &conn_hash_table_ops)) {
1392 palkovsky 384
        printf("%s: cannot create hash table\n", "async");
385
        return ENOMEM;
386
    }
387
 
388
}
1427 palkovsky 389
 
390
/** IPC handler for messages in async framework
391
 *
392
 * Notify thread that is waiting for this message, that it arrived
393
 */
394
static void reply_received(void *private, int retval,
395
               ipc_call_t *data)
396
{
397
    amsg_t *msg = (amsg_t *) private;
398
 
399
    msg->retval = retval;
400
 
401
    futex_down(&async_futex);
402
    /* Copy data after futex_down, just in case the
403
     * call was detached
404
     */
405
    if (msg->dataptr)
406
        *msg->dataptr = *data;
407
 
408
    msg->done = 1;
409
    if (! msg->active) {
410
        msg->active = 1;
411
        psthread_add_ready(msg->ptid);
412
    }
413
    futex_up(&async_futex);
414
}
415
 
416
/** Send message and return id of the sent message
417
 *
418
 * The return value can be used as input for async_wait() to wait
419
 * for completion.
420
 */
421
aid_t async_send_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
422
           ipc_call_t *dataptr)
423
{
424
    amsg_t *msg;
425
 
426
    msg = malloc(sizeof(*msg));
427
    msg->active = 1;
428
    msg->done = 0;
429
    msg->dataptr = dataptr;
430
    ipc_call_async_2(phoneid,method,arg1,arg2,msg,reply_received);
431
 
432
    return (aid_t) msg;
433
}
434
 
435
/** Wait for a message sent by async framework
436
 *
437
 * @param amsgid Message ID to wait for
438
 * @param retval Pointer to variable where will be stored retval
439
 *               of the answered message. If NULL, it is ignored.
440
 *
441
 */
442
void async_wait_for(aid_t amsgid, ipcarg_t *retval)
443
{
444
    amsg_t *msg = (amsg_t *) amsgid;
445
    connection_t *conn;
446
 
447
    futex_down(&async_futex);
448
    if (msg->done) {
449
        futex_up(&async_futex);
450
        goto done;
451
    }
452
 
453
    msg->ptid = psthread_get_id();
454
    msg->active = 0;
455
    /* Leave locked async_futex when entering this function */
456
    psthread_schedule_next_adv(PS_TO_MANAGER);
457
    /* futex is up automatically after psthread_schedule_next...*/
458
done:
459
    if (retval)
460
        *retval = msg->retval;
461
    free(msg);
462
}