| 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 <libadt/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); |
| } |
| |
| /** |
| * @} |
| */ |