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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. /** @addtogroup genericproc
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Task management.
  36.  */
  37.  
  38. #include <main/uinit.h>
  39. #include <proc/thread.h>
  40. #include <proc/task.h>
  41. #include <proc/uarg.h>
  42. #include <mm/as.h>
  43. #include <mm/slab.h>
  44. #include <synch/spinlock.h>
  45. #include <arch.h>
  46. #include <panic.h>
  47. #include <adt/btree.h>
  48. #include <adt/list.h>
  49. #include <ipc/ipc.h>
  50. #include <security/cap.h>
  51. #include <memstr.h>
  52. #include <print.h>
  53. #include <elf.h>
  54. #include <errno.h>
  55. #include <syscall/copy.h>
  56. #include <console/klog.h>
  57.  
  58. #ifndef LOADED_PROG_STACK_PAGES_NO
  59. #define LOADED_PROG_STACK_PAGES_NO 1
  60. #endif
  61.  
  62. /** Spinlock protecting the tasks_btree B+tree. */
  63. SPINLOCK_INITIALIZE(tasks_lock);
  64.  
  65. /** B+tree of active tasks.
  66.  *
  67.  * The task is guaranteed to exist after it was found in the tasks_btree as long as:
  68.  * @li the tasks_lock is held,
  69.  * @li the task's lock is held when task's lock is acquired before releasing tasks_lock or
  70.  * @li the task's refcount is grater than 0
  71.  *
  72.  */
  73. btree_t tasks_btree;
  74.  
  75. static task_id_t task_counter = 0;
  76.  
  77. static void ktaskclnp(void *arg);
  78. static void ktaskgc(void *arg);
  79.  
  80. /** Initialize tasks
  81.  *
  82.  * Initialize kernel tasks support.
  83.  *
  84.  */
  85. void task_init(void)
  86. {
  87.     TASK = NULL;
  88.     btree_create(&tasks_btree);
  89. }
  90.  
  91.  
  92. /** Create new task
  93.  *
  94.  * Create new task with no threads.
  95.  *
  96.  * @param as Task's address space.
  97.  * @param name Symbolic name.
  98.  *
  99.  * @return New task's structure
  100.  *
  101.  */
  102. task_t *task_create(as_t *as, char *name)
  103. {
  104.     ipl_t ipl;
  105.     task_t *ta;
  106.     int i;
  107.    
  108.     ta = (task_t *) malloc(sizeof(task_t), 0);
  109.  
  110.     task_create_arch(ta);
  111.  
  112.     spinlock_initialize(&ta->lock, "task_ta_lock");
  113.     list_initialize(&ta->th_head);
  114.     ta->as = as;
  115.     ta->name = name;
  116.     ta->main_thread = NULL;
  117.     ta->refcount = 0;
  118.     ta->context = CONTEXT;
  119.  
  120.     ta->capabilities = 0;
  121.     ta->accept_new_threads = true;
  122.    
  123.     ipc_answerbox_init(&ta->answerbox);
  124.     for (i = 0; i < IPC_MAX_PHONES; i++)
  125.         ipc_phone_init(&ta->phones[i]);
  126.     if ((ipc_phone_0) && (context_check(ipc_phone_0->task->context, ta->context)))
  127.         ipc_phone_connect(&ta->phones[0], ipc_phone_0);
  128.     atomic_set(&ta->active_calls, 0);
  129.  
  130.     mutex_initialize(&ta->futexes_lock);
  131.     btree_create(&ta->futexes);
  132.    
  133.     ipl = interrupts_disable();
  134.  
  135.     /*
  136.      * Increment address space reference count.
  137.      * TODO: Reconsider the locking scheme.
  138.      */
  139.     mutex_lock(&as->lock);
  140.     as->refcount++;
  141.     mutex_unlock(&as->lock);
  142.  
  143.     spinlock_lock(&tasks_lock);
  144.  
  145.     ta->taskid = ++task_counter;
  146.     btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
  147.  
  148.     spinlock_unlock(&tasks_lock);
  149.     interrupts_restore(ipl);
  150.  
  151.     return ta;
  152. }
  153.  
  154. /** Destroy task.
  155.  *
  156.  * @param t Task to be destroyed.
  157.  */
  158. void task_destroy(task_t *t)
  159. {
  160.     task_destroy_arch(t);
  161.     btree_destroy(&t->futexes);
  162.  
  163.     mutex_lock_active(&t->as->lock);
  164.     if (--t->as->refcount == 0) {
  165.         mutex_unlock(&t->as->lock);
  166.         as_destroy(t->as);
  167.         /*
  168.          * t->as is destroyed.
  169.          */
  170.     } else {
  171.         mutex_unlock(&t->as->lock);
  172.     }
  173.    
  174.     free(t);
  175.     TASK = NULL;
  176. }
  177.  
  178. /** Create new task with 1 thread and run it
  179.  *
  180.  * @param program_addr Address of program executable image.
  181.  * @param name Program name.
  182.  *
  183.  * @return Task of the running program or NULL on error.
  184.  */
  185. task_t * task_run_program(void *program_addr, char *name)
  186. {
  187.     as_t *as;
  188.     as_area_t *a;
  189.     int rc;
  190.     thread_t *t1, *t2;
  191.     task_t *task;
  192.     uspace_arg_t *kernel_uarg;
  193.  
  194.     as = as_create(0);
  195.     ASSERT(as);
  196.  
  197.     rc = elf_load((elf_header_t *) program_addr, as);
  198.     if (rc != EE_OK) {
  199.         as_destroy(as);
  200.         return NULL;
  201.     }
  202.    
  203.     kernel_uarg = (uspace_arg_t *) malloc(sizeof(uspace_arg_t), 0);
  204.     kernel_uarg->uspace_entry = (void *) ((elf_header_t *) program_addr)->e_entry;
  205.     kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
  206.     kernel_uarg->uspace_thread_function = NULL;
  207.     kernel_uarg->uspace_thread_arg = NULL;
  208.     kernel_uarg->uspace_uarg = NULL;
  209.    
  210.     task = task_create(as, name);
  211.     ASSERT(task);
  212.  
  213.     /*
  214.      * Create the data as_area.
  215.      */
  216.     a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
  217.         LOADED_PROG_STACK_PAGES_NO*PAGE_SIZE,
  218.         USTACK_ADDRESS, AS_AREA_ATTR_NONE, &anon_backend, NULL);
  219.  
  220.     /*
  221.      * Create the main thread.
  222.      */
  223.     t1 = thread_create(uinit, kernel_uarg, task, 0, "uinit");
  224.     ASSERT(t1);
  225.    
  226.     /*
  227.      * Create killer thread for the new task.
  228.      */
  229.     t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc");
  230.     ASSERT(t2);
  231.     thread_ready(t2);
  232.  
  233.     thread_ready(t1);
  234.  
  235.     return task;
  236. }
  237.  
  238. /** Syscall for reading task ID from userspace.
  239.  *
  240.  * @param uspace_task_id Userspace address of 8-byte buffer where to store current task ID.
  241.  *
  242.  * @return 0 on success or an error code from @ref errno.h.
  243.  */
  244. unative_t sys_task_get_id(task_id_t *uspace_task_id)
  245. {
  246.     /*
  247.      * No need to acquire lock on TASK because taskid
  248.      * remains constant for the lifespan of the task.
  249.      */
  250.     return (unative_t) copy_to_uspace(uspace_task_id, &TASK->taskid, sizeof(TASK->taskid));
  251. }
  252.  
  253. /** Find task structure corresponding to task ID.
  254.  *
  255.  * The tasks_lock must be already held by the caller of this function
  256.  * and interrupts must be disabled.
  257.  *
  258.  * @param id Task ID.
  259.  *
  260.  * @return Task structure address or NULL if there is no such task ID.
  261.  */
  262. task_t *task_find_by_id(task_id_t id)
  263. {
  264.     btree_node_t *leaf;
  265.    
  266.     return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
  267. }
  268.  
  269. /** Kill task.
  270.  *
  271.  * @param id ID of the task to be killed.
  272.  *
  273.  * @return 0 on success or an error code from errno.h
  274.  */
  275. int task_kill(task_id_t id)
  276. {
  277.     ipl_t ipl;
  278.     task_t *ta;
  279.     thread_t *t;
  280.     link_t *cur;
  281.  
  282.     if (id == 1)
  283.         return EPERM;
  284.    
  285.     ipl = interrupts_disable();
  286.     spinlock_lock(&tasks_lock);
  287.  
  288.     if (!(ta = task_find_by_id(id))) {
  289.         spinlock_unlock(&tasks_lock);
  290.         interrupts_restore(ipl);
  291.         return ENOENT;
  292.     }
  293.  
  294.     spinlock_lock(&ta->lock);
  295.     ta->refcount++;
  296.     spinlock_unlock(&ta->lock);
  297.  
  298.     btree_remove(&tasks_btree, ta->taskid, NULL);
  299.     spinlock_unlock(&tasks_lock);
  300.    
  301.     t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp");
  302.    
  303.     spinlock_lock(&ta->lock);
  304.     ta->accept_new_threads = false;
  305.     ta->refcount--;
  306.  
  307.     /*
  308.      * Interrupt all threads except ktaskclnp.
  309.      */
  310.     for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
  311.         thread_t *thr;
  312.         bool  sleeping = false;
  313.        
  314.         thr = list_get_instance(cur, thread_t, th_link);
  315.         if (thr == t)
  316.             continue;
  317.            
  318.         spinlock_lock(&thr->lock);
  319.         thr->interrupted = true;
  320.         if (thr->state == Sleeping)
  321.             sleeping = true;
  322.         spinlock_unlock(&thr->lock);
  323.        
  324.         if (sleeping)
  325.             waitq_interrupt_sleep(thr);
  326.     }
  327.    
  328.     spinlock_unlock(&ta->lock);
  329.     interrupts_restore(ipl);
  330.    
  331.     if (t)
  332.         thread_ready(t);
  333.  
  334.     return 0;
  335. }
  336.  
  337. /** Print task list */
  338. void task_print_list(void)
  339. {
  340.     link_t *cur;
  341.     ipl_t ipl;
  342.    
  343.     /* Messing with thread structures, avoid deadlock */
  344.     ipl = interrupts_disable();
  345.     spinlock_lock(&tasks_lock);
  346.  
  347.     for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head; cur = cur->next) {
  348.         btree_node_t *node;
  349.         int i;
  350.        
  351.         node = list_get_instance(cur, btree_node_t, leaf_link);
  352.         for (i = 0; i < node->keys; i++) {
  353.             task_t *t;
  354.             int j;
  355.  
  356.             t = (task_t *) node->value[i];
  357.        
  358.             spinlock_lock(&t->lock);
  359.             printf("%s(%lld): context=%ld, address=%#zx, as=%#zx, ActiveCalls: %zd",
  360.                 t->name, t->taskid, t->context, t, t->as, atomic_get(&t->active_calls));
  361.             for (j=0; j < IPC_MAX_PHONES; j++) {
  362.                 if (t->phones[j].callee)
  363.                     printf(" Ph(%zd): %#zx ", j, t->phones[j].callee);
  364.             }
  365.             printf("\n");
  366.             spinlock_unlock(&t->lock);
  367.         }
  368.     }
  369.  
  370.     spinlock_unlock(&tasks_lock);
  371.     interrupts_restore(ipl);
  372. }
  373.  
  374. /** Kernel thread used to cleanup the task after it is killed. */
  375. void ktaskclnp(void *arg)
  376. {
  377.     ipl_t ipl;
  378.     thread_t *t = NULL, *main_thread;
  379.     link_t *cur;
  380.     bool again;
  381.  
  382.     thread_detach(THREAD);
  383.  
  384. loop:
  385.     ipl = interrupts_disable();
  386.     spinlock_lock(&TASK->lock);
  387.    
  388.     main_thread = TASK->main_thread;
  389.    
  390.     /*
  391.      * Find a thread to join.
  392.      */
  393.     again = false;
  394.     for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  395.         t = list_get_instance(cur, thread_t, th_link);
  396.  
  397.         spinlock_lock(&t->lock);
  398.         if (t == THREAD) {
  399.             spinlock_unlock(&t->lock);
  400.             continue;
  401.         } else if (t == main_thread) {
  402.             spinlock_unlock(&t->lock);
  403.             continue;
  404.         } else if (t->join_type != None) {
  405.             spinlock_unlock(&t->lock);
  406.             again = true;
  407.             continue;
  408.         } else {
  409.             t->join_type = TaskClnp;
  410.             spinlock_unlock(&t->lock);
  411.             again = false;
  412.             break;
  413.         }
  414.     }
  415.    
  416.     spinlock_unlock(&TASK->lock);
  417.     interrupts_restore(ipl);
  418.    
  419.     if (again) {
  420.         /*
  421.          * Other cleanup (e.g. ktaskgc) is in progress.
  422.          */
  423.         scheduler();
  424.         goto loop;
  425.     }
  426.    
  427.     if (t != THREAD) {
  428.         ASSERT(t != main_thread);   /* uninit is joined and detached in ktaskgc */
  429.         thread_join(t);
  430.         thread_detach(t);
  431.         goto loop;  /* go for another thread */
  432.     }
  433.    
  434.     /*
  435.      * Now there are no other threads in this task
  436.      * and no new threads can be created.
  437.      */
  438.    
  439.     ipc_cleanup();
  440.     futex_cleanup();
  441.     klog_printf("Cleanup of task %lld completed.", TASK->taskid);
  442. }
  443.  
  444. /** Kernel thread used to kill the userspace task when its main thread exits.
  445.  *
  446.  * This thread waits until the main userspace thread (i.e. uninit) exits.
  447.  * When this happens, the task is killed. In the meantime, exited threads
  448.  * are garbage collected.
  449.  *
  450.  * @param arg Pointer to the thread structure of the task's main thread.
  451.  */
  452. void ktaskgc(void *arg)
  453. {
  454.     thread_t *t = (thread_t *) arg;
  455. loop:  
  456.     /*
  457.      * Userspace threads cannot detach themselves,
  458.      * therefore the thread pointer is guaranteed to be valid.
  459.      */
  460.     if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) == ESYNCH_TIMEOUT) {  /* sleep uninterruptibly here! */
  461.         ipl_t ipl;
  462.         link_t *cur;
  463.         thread_t *thr = NULL;
  464.    
  465.         /*
  466.          * The join timed out. Try to do some garbage collection of Undead threads.
  467.          */
  468. more_gc:       
  469.         ipl = interrupts_disable();
  470.         spinlock_lock(&TASK->lock);
  471.        
  472.         for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
  473.             thr = list_get_instance(cur, thread_t, th_link);
  474.             spinlock_lock(&thr->lock);
  475.             if (thr != t && thr->state == Undead && thr->join_type == None) {
  476.                 thr->join_type = TaskGC;
  477.                 spinlock_unlock(&thr->lock);
  478.                 break;
  479.             }
  480.             spinlock_unlock(&thr->lock);
  481.             thr = NULL;
  482.         }
  483.         spinlock_unlock(&TASK->lock);
  484.         interrupts_restore(ipl);
  485.        
  486.         if (thr) {
  487.             thread_join(thr);
  488.             thread_detach(thr);
  489.             scheduler();
  490.             goto more_gc;
  491.         }
  492.            
  493.         goto loop;
  494.     }
  495.     thread_detach(t);
  496.     task_kill(TASK->taskid);
  497. }
  498.  
  499. /** @}
  500.  */
  501.