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  1. /*
  2.  * Copyright (c) 2008 Jiri Svoboda
  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.  
  29. /** @addtogroup genericipc
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <synch/synch.h>
  36. #include <synch/spinlock.h>
  37. #include <synch/mutex.h>
  38. #include <ipc/ipc.h>
  39. #include <ipc/ipcrsc.h>
  40. #include <arch.h>
  41. #include <errno.h>
  42. #include <debug.h>
  43. #include <udebug/udebug_ipc.h>
  44. #include <ipc/kbox.h>
  45.  
  46. void ipc_kbox_cleanup(void)
  47. {
  48.     ipl_t ipl;
  49.     bool have_kb_thread;
  50.  
  51.     /*
  52.      * Only hold kb.cleanup_lock while setting kb.finished -
  53.      * this is enough.
  54.      */
  55.     mutex_lock(&TASK->kb.cleanup_lock);
  56.     TASK->kb.finished = true;
  57.     mutex_unlock(&TASK->kb.cleanup_lock);
  58.  
  59.     have_kb_thread = (TASK->kb.thread != NULL);
  60.  
  61.     /*
  62.      * From now on nobody will try to connect phones or attach
  63.      * kbox threads
  64.      */
  65.  
  66.     /*
  67.      * Disconnect all phones connected to our kbox. Passing true for
  68.      * notify_box causes a HANGUP message to be inserted for each
  69.      * disconnected phone. This ensures the kbox thread is going to
  70.      * wake up and terminate.
  71.      */
  72.     ipc_answerbox_slam_phones(&TASK->kb.box, have_kb_thread);
  73.  
  74.     /*
  75.      * If the task was being debugged, clean up debugging session.
  76.      * This is necessarry as slamming the phones won't force
  77.      * kbox thread to clean it up since sender != debugger.
  78.      */
  79.     ipl = interrupts_disable();
  80.     spinlock_lock(&TASK->lock);
  81.     udebug_task_cleanup(TASK);
  82.     spinlock_unlock(&TASK->lock);
  83.     interrupts_restore(ipl);
  84.    
  85.     if (have_kb_thread) {
  86.         LOG("join kb.thread..\n");
  87.         thread_join(TASK->kb.thread);
  88.         thread_detach(TASK->kb.thread);
  89.         LOG("join done\n");
  90.         TASK->kb.thread = NULL;
  91.     }
  92.  
  93.     /* Answer all messages in 'calls' and 'dispatched_calls' queues. */
  94.     spinlock_lock(&TASK->kb.box.lock);
  95.     ipc_cleanup_call_list(&TASK->kb.box.dispatched_calls);
  96.     ipc_cleanup_call_list(&TASK->kb.box.calls);
  97.     spinlock_unlock(&TASK->kb.box.lock);
  98. }
  99.  
  100. /** Handle hangup message in kbox.
  101.  *
  102.  * @param call  The IPC_M_PHONE_HUNGUP call structure.
  103.  * @param last  Output, the function stores @c true here if
  104.  *      this was the last phone, @c false otherwise.
  105.  **/
  106. static void kbox_proc_phone_hungup(call_t *call, bool *last)
  107. {
  108.     ipl_t ipl;
  109.  
  110.     LOG("kbox_proc_phone_hungup()\n");
  111.  
  112.     /* Was it our debugger, who hung up? */
  113.     if (call->sender == TASK->udebug.debugger) {
  114.         /* Terminate debugging session (if any). */
  115.         LOG("kbox: terminate debug session\n");
  116.         ipl = interrupts_disable();
  117.         spinlock_lock(&TASK->lock);
  118.         udebug_task_cleanup(TASK);
  119.         spinlock_unlock(&TASK->lock);
  120.         interrupts_restore(ipl);
  121.     } else {
  122.         LOG("kbox: was not debugger\n");
  123.     }
  124.  
  125.     LOG("kbox: continue with hangup message\n");
  126.     IPC_SET_RETVAL(call->data, 0);
  127.     ipc_answer(&TASK->kb.box, call);
  128.  
  129.     ipl = interrupts_disable();
  130.     spinlock_lock(&TASK->lock);
  131.     spinlock_lock(&TASK->answerbox.lock);
  132.     if (list_empty(&TASK->answerbox.connected_phones)) {
  133.         /*
  134.          * Last phone has been disconnected. Detach this thread so it
  135.          * gets freed and signal to the caller.
  136.          */
  137.  
  138.         /* Only detach kbox thread unless already terminating. */
  139.         mutex_lock(&TASK->kb.cleanup_lock);
  140.         if (&TASK->kb.finished == false) {
  141.             /* Detach kbox thread so it gets freed from memory. */
  142.             thread_detach(TASK->kb.thread);
  143.             TASK->kb.thread = NULL;
  144.         }
  145.         mutex_unlock(&TASK->kb.cleanup_lock);
  146.  
  147.         LOG("phone list is empty\n");
  148.         *last = true;
  149.     } else {
  150.         *last = false;
  151.     }
  152.  
  153.     spinlock_unlock(&TASK->answerbox.lock);
  154.     spinlock_unlock(&TASK->lock);
  155.     interrupts_restore(ipl);
  156. }
  157.  
  158. /** Implementing function for the kbox thread.
  159.  *
  160.  * This function listens for debug requests. It terminates
  161.  * when all phones are disconnected from the kbox.
  162.  *
  163.  * @param arg   Ignored.
  164.  */
  165. static void kbox_thread_proc(void *arg)
  166. {
  167.     call_t *call;
  168.     bool done;
  169.  
  170.     (void)arg;
  171.     LOG("kbox_thread_proc()\n");
  172.     done = false;
  173.  
  174.     while (!done) {
  175.         call = ipc_wait_for_call(&TASK->kb.box, SYNCH_NO_TIMEOUT,
  176.             SYNCH_FLAGS_NONE);
  177.  
  178.         if (call == NULL)
  179.             continue;   /* Try again. */
  180.  
  181.         switch (IPC_GET_METHOD(call->data)) {
  182.  
  183.         case IPC_M_DEBUG_ALL:
  184.             /* Handle debug call. */
  185.             udebug_call_receive(call);
  186.             break;
  187.  
  188.         case IPC_M_PHONE_HUNGUP:
  189.             /*
  190.              * Process the hangup call. If this was the last
  191.              * phone, done will be set to true and the
  192.              * while loop will terminate.
  193.              */
  194.             kbox_proc_phone_hungup(call, &done);
  195.             break;
  196.  
  197.         default:
  198.             /* Ignore */
  199.             break;
  200.         }
  201.     }
  202.  
  203.     LOG("kbox: finished\n");
  204. }
  205.  
  206.  
  207. /**
  208.  * Connect phone to a task kernel-box specified by id.
  209.  *
  210.  * Note that this is not completely atomic. For optimisation reasons, the task
  211.  * might start cleaning up kbox after the phone has been connected and before
  212.  * a kbox thread has been created. This must be taken into account in the
  213.  * cleanup code.
  214.  *
  215.  * @return      Phone id on success, or negative error code.
  216.  */
  217. int ipc_connect_kbox(task_id_t taskid)
  218. {
  219.     int newphid;
  220.     task_t *ta;
  221.     thread_t *kb_thread;
  222.     ipl_t ipl;
  223.  
  224.     ipl = interrupts_disable();
  225.     spinlock_lock(&tasks_lock);
  226.  
  227.     ta = task_find_by_id(taskid);
  228.     if (ta == NULL) {
  229.         spinlock_unlock(&tasks_lock);
  230.         interrupts_restore(ipl);
  231.         return ENOENT;
  232.     }
  233.  
  234.     atomic_inc(&ta->refcount);
  235.  
  236.     spinlock_unlock(&tasks_lock);
  237.     interrupts_restore(ipl);
  238.  
  239.     mutex_lock(&ta->kb.cleanup_lock);
  240.  
  241.     if (atomic_predec(&ta->refcount) == 0) {
  242.         mutex_unlock(&ta->kb.cleanup_lock);
  243.         task_destroy(ta);
  244.         return ENOENT;
  245.     }
  246.  
  247.     if (ta->kb.finished != false) {
  248.         mutex_unlock(&ta->kb.cleanup_lock);
  249.         return EINVAL;
  250.     }
  251.  
  252.     newphid = phone_alloc();
  253.     if (newphid < 0) {
  254.         mutex_unlock(&ta->kb.cleanup_lock);
  255.         return ELIMIT;
  256.     }
  257.  
  258.     /* Connect the newly allocated phone to the kbox */
  259.     ipc_phone_connect(&TASK->phones[newphid], &ta->kb.box);
  260.  
  261.     if (ta->kb.thread != NULL) {
  262.         mutex_unlock(&ta->kb.cleanup_lock);
  263.         return newphid;
  264.     }
  265.  
  266.     /* Create a kbox thread */
  267.     kb_thread = thread_create(kbox_thread_proc, NULL, ta, 0,
  268.         "kbox", false);
  269.     if (!kb_thread) {
  270.         mutex_unlock(&ta->kb.cleanup_lock);
  271.         return ENOMEM;
  272.     }
  273.  
  274.     ta->kb.thread = kb_thread;
  275.     thread_ready(kb_thread);
  276.  
  277.     mutex_unlock(&ta->kb.cleanup_lock);
  278.  
  279.     return newphid;
  280. }
  281.  
  282. /** @}
  283.  */
  284.