0,0 → 1,269 |
/* |
* Copyright (c) 2009 Martin Decky |
* 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. |
*/ |
|
/** @addtogroup ns |
* @{ |
*/ |
|
#include <ipc/ipc.h> |
#include <adt/hash_table.h> |
#include <bool.h> |
#include <errno.h> |
#include <assert.h> |
#include <stdio.h> |
#include <macros.h> |
#include "task.h" |
#include "ns.h" |
|
#define TASK_HASH_TABLE_CHAINS 256 |
|
/* TODO: |
* |
* The current implementation of waiting on a task is not perfect. If somebody |
* wants to wait on a task which has already finished before the NS asked |
* the kernel to receive notifications, it would block indefinitively. |
* |
* A solution to this is to fail immediately on a task for which no creation |
* notification was received yet. However, there is a danger of a race condition |
* in this solution -- the caller has to make sure that it is not trying to wait |
* before the NS has a change to receive the task creation notification. This |
* can be assured by waiting for this event in task_spawn(). |
* |
* Finally, as there is currently no convention that each task has to be waited |
* for, the NS can leak memory because of the zombie tasks. |
* |
*/ |
|
/** Task hash table item. */ |
typedef struct { |
link_t link; |
task_id_t id; /**< Task ID. */ |
bool destroyed; |
} hashed_task_t; |
|
/** Compute hash index into task hash table. |
* |
* @param key Pointer keys. However, only the first key (i.e. truncated task |
* number) is used to compute the hash index. |
* |
* @return Hash index corresponding to key[0]. |
* |
*/ |
static hash_index_t task_hash(unsigned long *key) |
{ |
assert(key); |
return (LOWER32(*key) % TASK_HASH_TABLE_CHAINS); |
} |
|
/** Compare a key with hashed item. |
* |
* @param key Array of keys. |
* @param keys Must be lesser or equal to 2. |
* @param item Pointer to a hash table item. |
* |
* @return Non-zero if the key matches the item, zero otherwise. |
* |
*/ |
static int task_compare(unsigned long key[], hash_count_t keys, link_t *item) |
{ |
assert(key); |
assert(keys <= 2); |
assert(item); |
|
hashed_task_t *ht = hash_table_get_instance(item, hashed_task_t, link); |
|
if (keys == 2) |
return ((LOWER32(key[1]) == UPPER32(ht->id)) |
&& (LOWER32(key[0]) == LOWER32(ht->id))); |
else |
return (LOWER32(key[0]) == LOWER32(ht->id)); |
} |
|
/** Perform actions after removal of item from the hash table. |
* |
* @param item Item that was removed from the hash table. |
* |
*/ |
static void task_remove(link_t *item) |
{ |
assert(item); |
free(hash_table_get_instance(item, hashed_task_t, link)); |
} |
|
/** Operations for task hash table. */ |
static hash_table_operations_t task_hash_table_ops = { |
.hash = task_hash, |
.compare = task_compare, |
.remove_callback = task_remove |
}; |
|
/** Task hash table structure. */ |
static hash_table_t task_hash_table; |
|
/** Pending task wait structure. */ |
typedef struct { |
link_t link; |
task_id_t id; /**< Task ID. */ |
ipc_callid_t callid; /**< Call ID waiting for the connection */ |
} pending_wait_t; |
|
static link_t pending_wait; |
|
int task_init(void) |
{ |
if (!hash_table_create(&task_hash_table, TASK_HASH_TABLE_CHAINS, |
2, &task_hash_table_ops)) { |
printf(NAME ": No memory available for tasks\n"); |
return ENOMEM; |
} |
|
if (event_subscribe(EVENT_WAIT, 0) != EOK) |
printf(NAME ": Error registering wait notifications\n"); |
|
list_initialize(&pending_wait); |
|
return EOK; |
} |
|
/** Process pending wait requests */ |
void process_pending_wait(void) |
{ |
link_t *cur; |
|
loop: |
for (cur = pending_wait.next; cur != &pending_wait; cur = cur->next) { |
pending_wait_t *pr = list_get_instance(cur, pending_wait_t, link); |
|
unsigned long keys[2] = { |
LOWER32(pr->id), |
UPPER32(pr->id) |
}; |
|
link_t *link = hash_table_find(&task_hash_table, keys); |
if (!link) |
continue; |
|
hashed_task_t *ht = hash_table_get_instance(link, hashed_task_t, link); |
if (!ht->destroyed) |
continue; |
|
if (!(pr->callid & IPC_CALLID_NOTIFICATION)) |
ipc_answer_0(pr->callid, EOK); |
|
hash_table_remove(&task_hash_table, keys, 2); |
list_remove(cur); |
free(pr); |
goto loop; |
} |
} |
|
static void fail_pending_wait(task_id_t id, int rc) |
{ |
link_t *cur; |
|
loop: |
for (cur = pending_wait.next; cur != &pending_wait; cur = cur->next) { |
pending_wait_t *pr = list_get_instance(cur, pending_wait_t, link); |
|
if (pr->id == id) { |
if (!(pr->callid & IPC_CALLID_NOTIFICATION)) |
ipc_answer_0(pr->callid, rc); |
|
list_remove(cur); |
free(pr); |
goto loop; |
} |
} |
} |
|
void wait_notification(wait_type_t et, task_id_t id) |
{ |
unsigned long keys[2] = { |
LOWER32(id), |
UPPER32(id) |
}; |
|
link_t *link = hash_table_find(&task_hash_table, keys); |
|
if (link == NULL) { |
hashed_task_t *ht = |
(hashed_task_t *) malloc(sizeof(hashed_task_t)); |
if (ht == NULL) { |
fail_pending_wait(id, ENOMEM); |
return; |
} |
|
link_initialize(&ht->link); |
ht->id = id; |
ht->destroyed = (et == TASK_CREATE) ? false : true; |
hash_table_insert(&task_hash_table, keys, &ht->link); |
} else { |
hashed_task_t *ht = |
hash_table_get_instance(link, hashed_task_t, link); |
ht->destroyed = (et == TASK_CREATE) ? false : true; |
} |
} |
|
void wait_for_task(task_id_t id, ipc_call_t *call, ipc_callid_t callid) |
{ |
ipcarg_t retval; |
unsigned long keys[2] = { |
LOWER32(id), |
UPPER32(id) |
}; |
|
link_t *link = hash_table_find(&task_hash_table, keys); |
hashed_task_t *ht = (link != NULL) ? |
hash_table_get_instance(link, hashed_task_t, link) : NULL; |
|
if ((ht == NULL) || (!ht->destroyed)) { |
/* Add to pending list */ |
pending_wait_t *pr = |
(pending_wait_t *) malloc(sizeof(pending_wait_t)); |
if (!pr) { |
retval = ENOMEM; |
goto out; |
} |
|
pr->id = id; |
pr->callid = callid; |
list_append(&pr->link, &pending_wait); |
return; |
} |
|
hash_table_remove(&task_hash_table, keys, 2); |
retval = EOK; |
|
out: |
if (!(callid & IPC_CALLID_NOTIFICATION)) |
ipc_answer_0(callid, retval); |
} |
|
/** |
* @} |
*/ |