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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  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. /**
  30.  * @file    task.c
  31.  * @brief   Task management.
  32.  */
  33.  
  34. #include <main/uinit.h>
  35. #include <proc/thread.h>
  36. #include <proc/task.h>
  37. #include <proc/uarg.h>
  38. #include <mm/as.h>
  39. #include <mm/slab.h>
  40. #include <synch/spinlock.h>
  41. #include <arch.h>
  42. #include <panic.h>
  43. #include <adt/btree.h>
  44. #include <adt/list.h>
  45. #include <ipc/ipc.h>
  46. #include <security/cap.h>
  47. #include <memstr.h>
  48. #include <print.h>
  49. #include <elf.h>
  50. #include <errno.h>
  51. #include <syscall/copy.h>
  52. #include <console/klog.h>
  53.  
  54. #ifndef LOADED_PROG_STACK_PAGES_NO
  55. #define LOADED_PROG_STACK_PAGES_NO 1
  56. #endif
  57.  
  58. SPINLOCK_INITIALIZE(tasks_lock);
  59. btree_t tasks_btree;
  60. static task_id_t task_counter = 0;
  61.  
  62. static void ktaskclnp(void *arg);
  63. static void ktaskkill(void *arg);
  64.  
  65. /** Initialize tasks
  66.  *
  67.  * Initialize kernel tasks support.
  68.  *
  69.  */
  70. void task_init(void)
  71. {
  72.     TASK = NULL;
  73.     btree_create(&tasks_btree);
  74. }
  75.  
  76.  
  77. /** Create new task
  78.  *
  79.  * Create new task with no threads.
  80.  *
  81.  * @param as Task's address space.
  82.  * @param name Symbolic name.
  83.  *
  84.  * @return New task's structure
  85.  *
  86.  */
  87. task_t *task_create(as_t *as, char *name)
  88. {
  89.     ipl_t ipl;
  90.     task_t *ta;
  91.     int i;
  92.    
  93.     ta = (task_t *) malloc(sizeof(task_t), 0);
  94.  
  95.     task_create_arch(ta);
  96.  
  97.     spinlock_initialize(&ta->lock, "task_ta_lock");
  98.     list_initialize(&ta->th_head);
  99.     ta->as = as;
  100.     ta->name = name;
  101.     ta->main_thread = NULL;
  102.     ta->refcount = 0;
  103.  
  104.     ta->capabilities = 0;
  105.     ta->accept_new_threads = true;
  106.    
  107.     ipc_answerbox_init(&ta->answerbox);
  108.     for (i=0; i < IPC_MAX_PHONES;i++)
  109.         ipc_phone_init(&ta->phones[i]);
  110.     if (ipc_phone_0)
  111.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  112.     atomic_set(&ta->active_calls, 0);
  113.  
  114.     mutex_initialize(&ta->futexes_lock);
  115.     btree_create(&ta->futexes);
  116.    
  117.     ipl = interrupts_disable();
  118.  
  119.     /*
  120.      * Increment address space reference count.
  121.      * TODO: Reconsider the locking scheme.
  122.      */
  123.     mutex_lock(&as->lock);
  124.     as->refcount++;
  125.     mutex_unlock(&as->lock);
  126.  
  127.     spinlock_lock(&tasks_lock);
  128.  
  129.     ta->taskid = ++task_counter;
  130.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  131.  
  132.     spinlock_unlock(&tasks_lock);
  133.     interrupts_restore(ipl);
  134.  
  135.     return ta;
  136. }
  137.  
  138. /** Destroy task.
  139.  *
  140.  * @param t Task to be destroyed.
  141.  */
  142. void task_destroy(task_t *t)
  143. {
  144.     task_destroy_arch(t);
  145.     btree_destroy(&t->futexes);
  146.  
  147.     mutex_lock_active(&t->as->lock);
  148.     if (--t->as->refcount == 0) {
  149.         mutex_unlock(&t->as->lock);
  150.         as_destroy(t->as);
  151.         /*
  152.          * t->as is destroyed.
  153.          */
  154.     } else {
  155.         mutex_unlock(&t->as->lock);
  156.     }
  157.    
  158.     free(t);
  159.     TASK = NULL;
  160. }
  161.  
  162. /** Create new task with 1 thread and run it
  163.  *
  164.  * @param program_addr Address of program executable image.
  165.  * @param name Program name.
  166.  *
  167.  * @return Task of the running program or NULL on error.
  168.  */
  169. task_t * task_run_program(void *program_addr, char *name)
  170. {
  171.     as_t *as;
  172.     as_area_t *a;
  173.     int rc;
  174.     thread_t *t1, *t2;
  175.     task_t *task;
  176.     uspace_arg_t *kernel_uarg;
  177.  
  178.     as = as_create(0);
  179.     ASSERT(as);
  180.  
  181.     rc = elf_load((elf_header_t *) program_addr, as);
  182.     if (rc != EE_OK) {
  183.         as_destroy(as);
  184.         return NULL;
  185.     }
  186.    
  187.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  188.     kernel_uarg->uspace_entry = (void *) ((elf_header_t *) program_addr)->e_entry;
  189.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  190.     kernel_uarg->uspace_thread_function = NULL;
  191.     kernel_uarg->uspace_thread_arg = NULL;
  192.     kernel_uarg->uspace_uarg = NULL;
  193.    
  194.     task = task_create(as, name);
  195.     ASSERT(task);
  196.  
  197.     /*
  198.      * Create the data as_area.
  199.      */
  200.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  201.         LOADED_PROG_STACK_PAGES_NO*PAGE_SIZE,
  202.         USTACK_ADDRESS, AS_AREA_ATTR_NONE, &anon_backend, NULL);
  203.  
  204.     /*
  205.      * Create the main thread.
  206.      */
  207.     t1 = thread_create(uinit, kernel_uarg, task, 0, "uinit");
  208.     ASSERT(t1);
  209.    
  210.     /*
  211.      * Create killer thread for the new task.
  212.      */
  213.     t2 = thread_create(ktaskkill, t1, task, 0, "ktaskkill");
  214.     ASSERT(t2);
  215.     thread_ready(t2);
  216.  
  217.     thread_ready(t1);
  218.  
  219.     return task;
  220. }
  221.  
  222. /** Syscall for reading task ID from userspace.
  223.  *
  224.  * @param uspace_task_id Userspace address of 8-byte buffer where to store current task ID.
  225.  *
  226.  * @return 0 on success or an error code from @ref errno.h.
  227.  */
  228. __native sys_task_get_id(task_id_t *uspace_task_id)
  229. {
  230.     /*
  231.      * No need to acquire lock on TASK because taskid
  232.      * remains constant for the lifespan of the task.
  233.      */
  234.     return (__native) copy_to_uspace(uspace_task_id, &TASK->taskid, sizeof(TASK->taskid));
  235. }
  236.  
  237. /** Find task structure corresponding to task ID.
  238.  *
  239.  * The tasks_lock must be already held by the caller of this function
  240.  * and interrupts must be disabled.
  241.  *
  242.  * The task is guaranteed to exist after it was found in the tasks_btree as long as:
  243.  * @li the tasks_lock is held,
  244.  * @li the task's lock is held when task's lock is acquired before releasing tasks_lock or
  245.  * @li the task's refcount is grater than 0
  246.  *
  247.  * @param id Task ID.
  248.  *
  249.  * @return Task structure address or NULL if there is no such task ID.
  250.  */
  251. task_t *task_find_by_id(task_id_t id)
  252. {
  253.     btree_node_t *leaf;
  254.    
  255.     return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
  256. }
  257.  
  258. /** Kill task.
  259.  *
  260.  * @param id ID of the task to be killed.
  261.  *
  262.  * @return 0 on success or an error code from errno.h
  263.  */
  264. int task_kill(task_id_t id)
  265. {
  266.     ipl_t ipl;
  267.     task_t *ta;
  268.     thread_t *t;
  269.     link_t *cur;
  270.  
  271.     if (id == 1)
  272.         return EPERM;
  273.    
  274.     ipl = interrupts_disable();
  275.     spinlock_lock(&tasks_lock);
  276.  
  277.     if (!(ta = task_find_by_id(id))) {
  278.         spinlock_unlock(&tasks_lock);
  279.         interrupts_restore(ipl);
  280.         return ENOENT;
  281.     }
  282.  
  283.     spinlock_lock(&ta->lock);
  284.     ta->refcount++;
  285.     spinlock_unlock(&ta->lock);
  286.  
  287.     btree_remove(&tasks_btree, ta->taskid, NULL);
  288.     spinlock_unlock(&tasks_lock);
  289.    
  290.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp");
  291.    
  292.     spinlock_lock(&ta->lock);
  293.     ta->accept_new_threads = false;
  294.     ta->refcount--;
  295.  
  296.     /*
  297.      * Interrupt all threads except this one.
  298.      */
  299.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  300.         thread_t *thr;
  301.         bool  sleeping = false;
  302.        
  303.         thr = list_get_instance(cur, thread_t, th_link);
  304.         if (thr == t)
  305.             continue;
  306.            
  307.         spinlock_lock(&thr->lock);
  308.         thr->interrupted = true;
  309.         if (thr->state == Sleeping)
  310.             sleeping = true;
  311.         spinlock_unlock(&thr->lock);
  312.        
  313.         if (sleeping)
  314.             waitq_interrupt_sleep(thr);
  315.     }
  316.    
  317.     spinlock_unlock(&ta->lock);
  318.     interrupts_restore(ipl);
  319.    
  320.     if (t)
  321.         thread_ready(t);
  322.  
  323.     return 0;
  324. }
  325.  
  326. /** Print task list */
  327. void task_print_list(void)
  328. {
  329.     link_t *cur;
  330.     ipl_t ipl;
  331.    
  332.     /* Messing with thread structures, avoid deadlock */
  333.     ipl = interrupts_disable();
  334.     spinlock_lock(&tasks_lock);
  335.  
  336.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head; cur = cur->next) {
  337.         btree_node_t *node;
  338.         int i;
  339.        
  340.         node = list_get_instance(cur, btree_node_t, leaf_link);
  341.         for (i = 0; i < node->keys; i++) {
  342.             task_t *t;
  343.             int j;
  344.  
  345.             t = (task_t *) node->value[i];
  346.        
  347.             spinlock_lock(&t->lock);
  348.             printf("%s(%lld): address=%#zX, as=%#zX, ActiveCalls: %zd",
  349.                 t->name, t->taskid, t, t->as, atomic_get(&t->active_calls));
  350.             for (j=0; j < IPC_MAX_PHONES; j++) {
  351.                 if (t->phones[j].callee)
  352.                     printf(" Ph(%zd): %#zX ", j, t->phones[j].callee);
  353.             }
  354.             printf("\n");
  355.             spinlock_unlock(&t->lock);
  356.         }
  357.     }
  358.  
  359.     spinlock_unlock(&tasks_lock);
  360.     interrupts_restore(ipl);
  361. }
  362.  
  363. /** Kernel thread used to cleanup the task after it is killed. */
  364. void ktaskclnp(void *arg)
  365. {
  366.     ipl_t ipl;
  367.     thread_t *t = NULL, *main_thread;
  368.     link_t *cur;
  369.  
  370.     thread_detach(THREAD);
  371.  
  372. loop:
  373.     ipl = interrupts_disable();
  374.     spinlock_lock(&TASK->lock);
  375.    
  376.     main_thread = TASK->main_thread;
  377.    
  378.     /*
  379.      * Find a thread to join.
  380.      */
  381.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  382.         t = list_get_instance(cur, thread_t, th_link);
  383.         if (t == THREAD)
  384.             continue;
  385.         else if (t == main_thread)
  386.             continue;
  387.         else
  388.             break;
  389.     }
  390.    
  391.     spinlock_unlock(&TASK->lock);
  392.     interrupts_restore(ipl);
  393.    
  394.     if (t != THREAD) {
  395.         ASSERT(t != main_thread);   /* uninit is joined and detached in ktaskkill */
  396.         thread_join(t);
  397.         thread_detach(t);
  398.         goto loop;  /* go for another thread */
  399.     }
  400.    
  401.     /*
  402.      * Now there are no other threads in this task
  403.      * and no new threads can be created.
  404.      */
  405.    
  406.     ipc_cleanup();
  407.     futex_cleanup();
  408.     klog_printf("Cleanup of task %lld completed.", TASK->taskid);
  409. }
  410.  
  411. /** Kernel task used to kill a userspace task when its main thread exits.
  412.  *
  413.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  414.  * When this happens, the task is killed.
  415.  *
  416.  * @param arg Pointer to the thread structure of the task's main thread.
  417.  */
  418. void ktaskkill(void *arg)
  419. {
  420.     thread_t *t = (thread_t *) arg;
  421.    
  422.     /*
  423.      * Userspace threads cannot detach themselves,
  424.      * therefore the thread pointer is guaranteed to be valid.
  425.      */
  426.     thread_join(t); /* sleep uninterruptibly here! */
  427.     thread_detach(t);
  428.     task_kill(TASK->taskid);
  429. }
  430.