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