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1351 | palkovsky | 1 | /* |
2 | * Copyright (C) 2006 Ondrej Palkovsky |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
1392 | palkovsky | 29 | /** |
30 | * Asynchronous library |
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31 | * |
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32 | * The aim of this library is facilitating writing programs utilizing |
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33 | * the asynchronous nature of Helenos IPC, yet using a normal way |
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34 | * of programming. |
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35 | * |
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36 | * You should be able to write very simple multithreaded programs, |
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37 | * the async framework will automatically take care of most synchronization |
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38 | * problems. |
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39 | * |
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40 | * Default semantics: |
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41 | * - send() - send asynchronously. If the kernel refuses to send more |
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42 | * messages, [ try to get responses from kernel, if nothing |
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43 | * found, might try synchronous ] |
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44 | * |
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45 | * Example of use: |
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46 | * |
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47 | * 1) Multithreaded client application |
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48 | * create_thread(thread1); |
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49 | * create_thread(thread2); |
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50 | * ... |
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51 | * |
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52 | * thread1() { |
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53 | * conn = ipc_connect_me_to(); |
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54 | * c1 = send(conn); |
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55 | * c2 = send(conn); |
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56 | * wait_for(c1); |
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57 | * wait_for(c2); |
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58 | * } |
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59 | * |
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60 | * |
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61 | * 2) Multithreaded server application |
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62 | * main() { |
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63 | * wait_for_connection(new_connection); |
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64 | * } |
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65 | * |
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66 | * |
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67 | * new_connection(int connection) { |
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68 | * accept(connection); |
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69 | * msg = get_msg(); |
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70 | * handle(msg); |
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71 | * answer(msg); |
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72 | * |
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73 | * msg = get_msg(); |
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74 | * .... |
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75 | * } |
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1404 | palkovsky | 76 | * |
77 | * TODO: Detaching/joining dead psthreads? */ |
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1392 | palkovsky | 78 | */ |
79 | #include <futex.h> |
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80 | #include <async.h> |
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81 | #include <psthread.h> |
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82 | #include <stdio.h> |
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83 | #include <libadt/hash_table.h> |
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84 | #include <libadt/list.h> |
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85 | #include <ipc/ipc.h> |
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86 | #include <assert.h> |
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87 | #include <errno.h> |
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88 | |||
89 | static atomic_t conn_futex = FUTEX_INITIALIZER; |
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90 | static hash_table_t conn_hash_table; |
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91 | |||
92 | typedef struct { |
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93 | link_t link; |
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94 | ipc_callid_t callid; |
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95 | ipc_call_t call; |
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96 | } msg_t; |
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97 | |||
98 | typedef struct { |
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99 | link_t link; |
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100 | ipcarg_t in_phone_hash; /**< Incoming phone hash. */ |
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101 | link_t msg_queue; /**< Messages that should be delivered to this thread */ |
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102 | pstid_t ptid; /**< Thread associated with this connection */ |
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103 | int active; /**< If this thread is currently active */ |
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104 | /* Structures for connection opening packet */ |
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105 | ipc_callid_t callid; |
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106 | ipc_call_t call; |
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107 | } connection_t; |
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108 | |||
109 | __thread connection_t *PS_connection; |
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110 | |||
111 | /* Hash table functions */ |
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112 | |||
1404 | palkovsky | 113 | #define CONN_HASH_TABLE_CHAINS 32 |
1392 | palkovsky | 114 | |
115 | static hash_index_t conn_hash(unsigned long *key) |
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1351 | palkovsky | 116 | { |
1392 | palkovsky | 117 | assert(key); |
1404 | palkovsky | 118 | return ((*key) >> 4) % CONN_HASH_TABLE_CHAINS; |
1351 | palkovsky | 119 | } |
120 | |||
1392 | palkovsky | 121 | static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item) |
1351 | palkovsky | 122 | { |
1392 | palkovsky | 123 | connection_t *hs; |
124 | |||
125 | hs = hash_table_get_instance(item, connection_t, link); |
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126 | |||
127 | return key[0] == hs->in_phone_hash; |
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1351 | palkovsky | 128 | } |
129 | |||
1392 | palkovsky | 130 | static void conn_remove(link_t *item) |
1351 | palkovsky | 131 | { |
1392 | palkovsky | 132 | free(hash_table_get_instance(item, connection_t, link)); |
1351 | palkovsky | 133 | } |
134 | |||
1392 | palkovsky | 135 | |
136 | /** Operations for NS hash table. */ |
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137 | static hash_table_operations_t conn_hash_table_ops = { |
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138 | .hash = conn_hash, |
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139 | .compare = conn_compare, |
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140 | .remove_callback = conn_remove |
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141 | }; |
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142 | |||
143 | /** Try to route a call to an appropriate connection thread |
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144 | * |
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145 | */ |
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146 | static int route_call(ipc_callid_t callid, ipc_call_t *call) |
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1351 | palkovsky | 147 | { |
1392 | palkovsky | 148 | connection_t *conn; |
149 | msg_t *msg; |
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150 | link_t *hlp; |
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151 | unsigned long key; |
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152 | |||
153 | futex_down(&conn_futex); |
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154 | |||
155 | key = call->in_phone_hash; |
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156 | hlp = hash_table_find(&conn_hash_table, &key); |
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157 | if (!hlp) { |
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158 | futex_up(&conn_futex); |
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159 | return 0; |
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1351 | palkovsky | 160 | } |
1392 | palkovsky | 161 | conn = hash_table_get_instance(hlp, connection_t, link); |
1351 | palkovsky | 162 | |
1392 | palkovsky | 163 | msg = malloc(sizeof(*msg)); |
164 | msg->callid = callid; |
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165 | msg->call = *call; |
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166 | list_append(&msg->link, &conn->msg_queue); |
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167 | |||
168 | if (!conn->active) { |
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169 | conn->active = 1; |
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170 | psthread_add_ready(conn->ptid); |
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171 | } |
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1351 | palkovsky | 172 | |
1392 | palkovsky | 173 | futex_up(&conn_futex); |
174 | |||
175 | return 1; |
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176 | } |
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177 | |||
1404 | palkovsky | 178 | /** Return new incoming message for current(thread-local) connection */ |
1392 | palkovsky | 179 | ipc_callid_t async_get_call(ipc_call_t *call) |
180 | { |
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181 | msg_t *msg; |
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182 | ipc_callid_t callid; |
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183 | connection_t *conn; |
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184 | |||
185 | futex_down(&conn_futex); |
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186 | |||
187 | conn = PS_connection; |
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188 | /* If nothing in queue, wait until something appears */ |
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189 | if (list_empty(&conn->msg_queue)) { |
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190 | conn->active = 0; |
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191 | psthread_schedule_next_adv(PS_TO_MANAGER); |
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1351 | palkovsky | 192 | } |
193 | |||
1392 | palkovsky | 194 | msg = list_get_instance(conn->msg_queue.next, msg_t, link); |
195 | list_remove(&msg->link); |
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196 | callid = msg->callid; |
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197 | *call = msg->call; |
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198 | free(msg); |
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199 | |||
200 | futex_up(&conn_futex); |
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201 | return callid; |
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1351 | palkovsky | 202 | } |
203 | |||
1404 | palkovsky | 204 | /** Thread function that gets created on new connection |
205 | * |
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206 | * This function is defined as a weak symbol - to be redefined in |
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207 | * user code. |
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208 | */ |
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1392 | palkovsky | 209 | void client_connection(ipc_callid_t callid, ipc_call_t *call) |
210 | { |
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1404 | palkovsky | 211 | ipc_answer_fast(callid, ENOENT, 0, 0); |
1392 | palkovsky | 212 | } |
1351 | palkovsky | 213 | |
1404 | palkovsky | 214 | /** Wrapper for client connection thread |
215 | * |
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216 | * When new connection arrives, thread with this function is created. |
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217 | * It calls client_connection and does final cleanup. |
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218 | * |
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219 | * @parameter arg Connection structure pointer |
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220 | */ |
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1392 | palkovsky | 221 | static int connection_thread(void *arg) |
1351 | palkovsky | 222 | { |
1404 | palkovsky | 223 | unsigned long key; |
224 | msg_t *msg; |
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225 | |||
1392 | palkovsky | 226 | /* Setup thread local connection pointer */ |
227 | PS_connection = (connection_t *)arg; |
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228 | client_connection(PS_connection->callid, &PS_connection->call); |
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229 | |||
1404 | palkovsky | 230 | /* Remove myself from connection hash table */ |
1392 | palkovsky | 231 | futex_down(&conn_futex); |
1404 | palkovsky | 232 | key = PS_connection->in_phone_hash; |
233 | hash_table_remove(&conn_hash_table, &key, 1); |
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1392 | palkovsky | 234 | futex_up(&conn_futex); |
1404 | palkovsky | 235 | /* Answer all remaining messages with ehangup */ |
236 | while (!list_empty(&PS_connection->msg_queue)) { |
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237 | msg = list_get_instance(PS_connection->msg_queue.next, msg_t, link); |
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238 | list_remove(&msg->link); |
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239 | ipc_answer_fast(msg->callid, EHANGUP, 0, 0); |
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240 | free(msg); |
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241 | } |
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1351 | palkovsky | 242 | } |
1392 | palkovsky | 243 | |
244 | /** Create new thread for a new connection |
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245 | * |
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246 | * Creates new thread for connection, fills in connection |
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247 | * structures and inserts it into the hash table, so that |
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248 | * later we can easily do routing of messages to particular |
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249 | * threads. |
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250 | */ |
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251 | static void new_connection(ipc_callid_t callid, ipc_call_t *call) |
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252 | { |
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253 | pstid_t ptid; |
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254 | connection_t *conn; |
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255 | unsigned long key; |
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256 | |||
257 | conn = malloc(sizeof(*conn)); |
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258 | if (!conn) { |
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259 | ipc_answer_fast(callid, ENOMEM, 0, 0); |
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260 | return; |
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261 | } |
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262 | conn->in_phone_hash = IPC_GET_ARG3(*call); |
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263 | list_initialize(&conn->msg_queue); |
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264 | conn->ptid = psthread_create(connection_thread, conn); |
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265 | conn->callid = callid; |
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266 | conn->call = *call; |
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267 | conn->active = 1; /* We will activate it asap */ |
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268 | list_initialize(&conn->link); |
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269 | if (!conn->ptid) { |
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270 | free(conn); |
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271 | ipc_answer_fast(callid, ENOMEM, 0, 0); |
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272 | return; |
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273 | } |
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274 | key = conn->in_phone_hash; |
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275 | futex_down(&conn_futex); |
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276 | /* Add connection to hash table */ |
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277 | hash_table_insert(&conn_hash_table, &key, &conn->link); |
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278 | futex_up(&conn_futex); |
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279 | |||
280 | psthread_add_ready(conn->ptid); |
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281 | } |
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282 | |||
283 | /** Handle call to a task */ |
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284 | static void handle_call(ipc_callid_t callid, ipc_call_t *call) |
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285 | { |
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286 | if (route_call(callid, call)) |
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287 | return; |
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288 | |||
289 | switch (IPC_GET_METHOD(*call)) { |
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290 | case IPC_M_INTERRUPT: |
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291 | break; |
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292 | case IPC_M_CONNECT_ME_TO: |
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293 | /* Open new connection with thread etc. */ |
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294 | new_connection(callid, call); |
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295 | break; |
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296 | default: |
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297 | ipc_answer_fast(callid, EHANGUP, 0, 0); |
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298 | } |
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299 | } |
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300 | |||
301 | /** Endless loop dispatching incoming calls and answers */ |
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302 | int async_manager() |
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303 | { |
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304 | ipc_call_t call; |
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305 | ipc_callid_t callid; |
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306 | |||
307 | while (1) { |
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308 | if (psthread_schedule_next_adv(PS_FROM_MANAGER)) { |
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309 | futex_up(&conn_futex); /* conn_futex is always held |
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310 | * when entering manager thread |
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311 | */ |
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312 | continue; |
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313 | } |
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314 | callid = ipc_wait_cycle(&call,SYNCH_NO_TIMEOUT,SYNCH_BLOCKING); |
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315 | |||
316 | if (callid & IPC_CALLID_ANSWERED) |
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317 | continue; |
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318 | handle_call(callid, &call); |
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319 | } |
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320 | } |
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321 | |||
1404 | palkovsky | 322 | /** Function to start async_manager as a standalone thread |
323 | * |
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324 | * When more kernel threads are used, one async manager should |
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325 | * exist per thread. The particular implementation may change, |
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326 | * currently one async_manager is started automatically per kernel |
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327 | * thread except main thread. |
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328 | */ |
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1392 | palkovsky | 329 | static int async_manager_thread(void *arg) |
330 | { |
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331 | futex_up(&conn_futex); /* conn_futex is always locked when entering |
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332 | * manager */ |
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333 | async_manager(); |
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334 | } |
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335 | |||
336 | /** Add one manager to manager list */ |
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337 | void async_create_manager(void) |
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338 | { |
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339 | pstid_t ptid; |
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340 | |||
341 | ptid = psthread_create(async_manager_thread, NULL); |
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342 | psthread_add_manager(ptid); |
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343 | } |
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344 | |||
345 | /** Remove one manager from manager list */ |
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346 | void async_destroy_manager(void) |
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347 | { |
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348 | psthread_remove_manager(); |
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349 | } |
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350 | |||
351 | /** Initialize internal structures needed for async manager */ |
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352 | int _async_init(void) |
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353 | { |
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1404 | palkovsky | 354 | if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1, &conn_hash_table_ops)) { |
1392 | palkovsky | 355 | printf("%s: cannot create hash table\n", "async"); |
356 | return ENOMEM; |
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357 | } |
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358 | |||
359 | } |