/*
* Copyright (C) 2001-2004 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file task.c
* @brief Task management.
*/
#include <main/uinit.h>
#include <proc/thread.h>
#include <proc/task.h>
#include <proc/uarg.h>
#include <mm/as.h>
#include <mm/slab.h>
#include <synch/spinlock.h>
#include <arch.h>
#include <panic.h>
#include <adt/btree.h>
#include <adt/list.h>
#include <ipc/ipc.h>
#include <security/cap.h>
#include <memstr.h>
#include <print.h>
#include <elf.h>
#include <errno.h>
#include <syscall/copy.h>
#include <console/klog.h>
#ifndef LOADED_PROG_STACK_PAGES_NO
#define LOADED_PROG_STACK_PAGES_NO 1
#endif
/** Spinlock protecting the tasks_btree B+tree. */
SPINLOCK_INITIALIZE(tasks_lock);
/** B+tree of active tasks.
*
* The task is guaranteed to exist after it was found in the tasks_btree as long as:
* @li the tasks_lock is held,
* @li the task's lock is held when task's lock is acquired before releasing tasks_lock or
* @li the task's refcount is grater than 0
*
*/
btree_t tasks_btree;
static task_id_t task_counter = 0;
static void ktaskclnp(void *arg);
static void ktaskgc(void *arg);
/** Initialize tasks
*
* Initialize kernel tasks support.
*
*/
void task_init(void)
{
TASK = NULL;
btree_create(&tasks_btree);
}
/** Create new task
*
* Create new task with no threads.
*
* @param as Task's address space.
* @param name Symbolic name.
*
* @return New task's structure
*
*/
task_t *task_create(as_t *as, char *name)
{
ipl_t ipl;
task_t *ta;
int i;
ta
= (task_t
*) malloc(sizeof(task_t
), 0);
task_create_arch(ta);
spinlock_initialize(&ta->lock, "task_ta_lock");
list_initialize(&ta->th_head);
ta->as = as;
ta->name = name;
ta->main_thread = NULL;
ta->refcount = 0;
ta->capabilities = 0;
ta->accept_new_threads = true;
ipc_answerbox_init(&ta->answerbox);
for (i=0; i < IPC_MAX_PHONES;i++)
ipc_phone_init(&ta->phones[i]);
if (ipc_phone_0)
ipc_phone_connect(&ta->phones[0], ipc_phone_0);
atomic_set(&ta->active_calls, 0);
mutex_initialize(&ta->futexes_lock);
btree_create(&ta->futexes);
ipl = interrupts_disable();
/*
* Increment address space reference count.
* TODO: Reconsider the locking scheme.
*/
mutex_lock(&as->lock);
as->refcount++;
mutex_unlock(&as->lock);
spinlock_lock(&tasks_lock);
ta->taskid = ++task_counter;
btree_insert(&tasks_btree, (btree_key_t) ta->taskid, (void *) ta, NULL);
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ta;
}
/** Destroy task.
*
* @param t Task to be destroyed.
*/
void task_destroy(task_t *t)
{
task_destroy_arch(t);
btree_destroy(&t->futexes);
mutex_lock_active(&t->as->lock);
if (--t->as->refcount == 0) {
mutex_unlock(&t->as->lock);
as_destroy(t->as);
/*
* t->as is destroyed.
*/
} else {
mutex_unlock(&t->as->lock);
}
TASK = NULL;
}
/** Create new task with 1 thread and run it
*
* @param program_addr Address of program executable image.
* @param name Program name.
*
* @return Task of the running program or NULL on error.
*/
task_t * task_run_program(void *program_addr, char *name)
{
as_t *as;
as_area_t *a;
int rc;
thread_t *t1, *t2;
task_t *task;
uspace_arg_t *kernel_uarg;
as = as_create(0);
ASSERT(as);
rc = elf_load((elf_header_t *) program_addr, as);
if (rc != EE_OK) {
as_destroy(as);
return NULL;
}
kernel_uarg
= (uspace_arg_t
*) malloc(sizeof(uspace_arg_t
), 0); kernel_uarg->uspace_entry = (void *) ((elf_header_t *) program_addr)->e_entry;
kernel_uarg->uspace_stack = (void *) USTACK_ADDRESS;
kernel_uarg->uspace_thread_function = NULL;
kernel_uarg->uspace_thread_arg = NULL;
kernel_uarg->uspace_uarg = NULL;
task = task_create(as, name);
ASSERT(task);
/*
* Create the data as_area.
*/
a = as_area_create(as, AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE,
LOADED_PROG_STACK_PAGES_NO*PAGE_SIZE,
USTACK_ADDRESS, AS_AREA_ATTR_NONE, &anon_backend, NULL);
/*
* Create the main thread.
*/
t1 = thread_create(uinit, kernel_uarg, task, 0, "uinit");
ASSERT(t1);
/*
* Create killer thread for the new task.
*/
t2 = thread_create(ktaskgc, t1, task, 0, "ktaskgc");
ASSERT(t2);
thread_ready(t2);
thread_ready(t1);
return task;
}
/** Syscall for reading task ID from userspace.
*
* @param uspace_task_id Userspace address of 8-byte buffer where to store current task ID.
*
* @return 0 on success or an error code from @ref errno.h.
*/
__native sys_task_get_id(task_id_t *uspace_task_id)
{
/*
* No need to acquire lock on TASK because taskid
* remains constant for the lifespan of the task.
*/
return (__native) copy_to_uspace(uspace_task_id, &TASK->taskid, sizeof(TASK->taskid));
}
/** Find task structure corresponding to task ID.
*
* The tasks_lock must be already held by the caller of this function
* and interrupts must be disabled.
*
* @param id Task ID.
*
* @return Task structure address or NULL if there is no such task ID.
*/
task_t *task_find_by_id(task_id_t id)
{
btree_node_t *leaf;
return (task_t *) btree_search(&tasks_btree, (btree_key_t) id, &leaf);
}
/** Kill task.
*
* @param id ID of the task to be killed.
*
* @return 0 on success or an error code from errno.h
*/
int task_kill(task_id_t id)
{
ipl_t ipl;
task_t *ta;
thread_t *t;
link_t *cur;
if (id == 1)
return EPERM;
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
if (!(ta = task_find_by_id(id))) {
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return ENOENT;
}
spinlock_lock(&ta->lock);
ta->refcount++;
spinlock_unlock(&ta->lock);
btree_remove(&tasks_btree, ta->taskid, NULL);
spinlock_unlock(&tasks_lock);
t = thread_create(ktaskclnp, NULL, ta, 0, "ktaskclnp");
spinlock_lock(&ta->lock);
ta->accept_new_threads = false;
ta->refcount--;
/*
* Interrupt all threads except ktaskclnp.
*/
for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
thread_t *thr;
bool sleeping = false;
thr = list_get_instance(cur, thread_t, th_link);
if (thr == t)
continue;
spinlock_lock(&thr->lock);
thr->interrupted = true;
if (thr->state == Sleeping)
sleeping = true;
spinlock_unlock(&thr->lock);
if (sleeping)
waitq_interrupt_sleep(thr);
}
spinlock_unlock(&ta->lock);
interrupts_restore(ipl);
if (t)
thread_ready(t);
return 0;
}
/** Print task list */
void task_print_list(void)
{
link_t *cur;
ipl_t ipl;
/* Messing with thread structures, avoid deadlock */
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
for (cur = tasks_btree.leaf_head.next; cur != &tasks_btree.leaf_head; cur = cur->next) {
btree_node_t *node;
int i;
node = list_get_instance(cur, btree_node_t, leaf_link);
for (i = 0; i < node->keys; i++) {
task_t *t;
int j;
t = (task_t *) node->value[i];
spinlock_lock(&t->lock);
printf("%s(%lld): address=%#zX, as=%#zX, ActiveCalls: %zd", t->name, t->taskid, t, t->as, atomic_get(&t->active_calls));
for (j=0; j < IPC_MAX_PHONES; j++) {
if (t->phones[j].callee)
printf(" Ph(%zd): %#zX ", j
, t
->phones
[j
].
callee); }
spinlock_unlock(&t->lock);
}
}
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
}
/** Kernel thread used to cleanup the task after it is killed. */
void ktaskclnp(void *arg)
{
ipl_t ipl;
thread_t *t = NULL, *main_thread;
link_t *cur;
bool again;
thread_detach(THREAD);
loop:
ipl = interrupts_disable();
spinlock_lock(&TASK->lock);
main_thread = TASK->main_thread;
/*
* Find a thread to join.
*/
again = false;
for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
t = list_get_instance(cur, thread_t, th_link);
spinlock_lock(&t->lock);
if (t == THREAD) {
spinlock_unlock(&t->lock);
continue;
} else if (t == main_thread) {
spinlock_unlock(&t->lock);
continue;
} else if (t->join_type != None) {
spinlock_unlock(&t->lock);
again = true;
continue;
} else {
t->join_type = TaskClnp;
spinlock_unlock(&t->lock);
again = false;
break;
}
}
spinlock_unlock(&TASK->lock);
interrupts_restore(ipl);
if (again) {
/*
* Other cleanup (e.g. ktaskgc) is in progress.
*/
scheduler();
goto loop;
}
if (t != THREAD) {
ASSERT(t != main_thread); /* uninit is joined and detached in ktaskgc */
thread_join(t);
thread_detach(t);
goto loop; /* go for another thread */
}
/*
* Now there are no other threads in this task
* and no new threads can be created.
*/
ipc_cleanup();
futex_cleanup();
klog_printf("Cleanup of task %lld completed.", TASK->taskid);
}
/** Kernel thread used to kill the userspace task when its main thread exits.
*
* This thread waits until the main userspace thread (i.e. uninit) exits.
* When this happens, the task is killed. In the meantime, exited threads
* are garbage collected.
*
* @param arg Pointer to the thread structure of the task's main thread.
*/
void ktaskgc(void *arg)
{
thread_t *t = (thread_t *) arg;
loop:
/*
* Userspace threads cannot detach themselves,
* therefore the thread pointer is guaranteed to be valid.
*/
if (thread_join_timeout(t, 1000000, SYNCH_FLAGS_NONE) == ESYNCH_TIMEOUT) { /* sleep uninterruptibly here! */
ipl_t ipl;
link_t *cur;
thread_t *thr = NULL;
/*
* The join timed out. Try to do some garbage collection of Undead threads.
*/
more_gc:
ipl = interrupts_disable();
spinlock_lock(&TASK->lock);
for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) {
thr = list_get_instance(cur, thread_t, th_link);
spinlock_lock(&thr->lock);
if (thr != t && thr->state == Undead && thr->join_type == None) {
thr->join_type = TaskGC;
spinlock_unlock(&thr->lock);
break;
}
spinlock_unlock(&thr->lock);
thr = NULL;
}
spinlock_unlock(&TASK->lock);
interrupts_restore(ipl);
if (thr) {
thread_join(thr);
thread_detach(thr);
scheduler();
goto more_gc;
}
goto loop;
}
thread_detach(t);
task_kill(TASK->taskid);
}