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Replaced usage of team_get_team_struct() with team_is_valid().

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Replaced some old error codes.
Explained a bit more how to solve a race condition.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@6681 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
2004-02-23 03:31:08 +00:00
parent 813b3cc53e
commit 2a3ec096a4
1 changed files with 17 additions and 12 deletions
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src/kernel/core/sem.c
+17 -12
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@@ -1,4 +1,9 @@
/* Semaphore code. Lots of "todo" items*/ /* Semaphore code. Lots of "todo" items */
/*
** Copyright 2002-2004, The OpenBeOS Team. All rights reserved.
** Distributed under the terms of the OpenBeOS License.
*/
/* /*
** Copyright 2001, Travis Geiselbrecht. All rights reserved. ** Copyright 2001, Travis Geiselbrecht. All rights reserved.
@@ -775,11 +780,7 @@ set_sem_owner(sem_id id, team_id team)
return B_NO_MORE_SEMS; return B_NO_MORE_SEMS;
if (id < 0) if (id < 0)
return B_BAD_SEM_ID; return B_BAD_SEM_ID;
if (team < 0) if (team < 0 || !team_is_valid(team))
return B_BAD_TEAM_ID;
// check if the team ID is valid
if (team_get_team_struct(team) == NULL)
return B_BAD_TEAM_ID; return B_BAD_TEAM_ID;
slot = id % MAX_SEMS; slot = id % MAX_SEMS;
@@ -794,9 +795,11 @@ set_sem_owner(sem_id id, team_id team)
return B_BAD_SEM_ID; return B_BAD_SEM_ID;
} }
// Todo: this is a small race condition: the team ID could already // ToDo: this is a small race condition: the team ID could already
// be invalid at this point - we would lose one semaphore slot in // be invalid at this point - we would lose one semaphore slot in
// this case! // this case!
// The only safe way to do this is to prevent either team (the new
// or the old owner) from dying until we leave the spinlock.
gSems[slot].u.used.owner = team; gSems[slot].u.used.owner = team;
RELEASE_SEM_LOCK(gSems[slot]); RELEASE_SEM_LOCK(gSems[slot]);
@@ -816,12 +819,13 @@ sem_interrupt_thread(struct thread *t)
int slot; int slot;
struct thread_queue wakeup_queue; struct thread_queue wakeup_queue;
TRACE(("sem_interrupt_thread: called on thread %p (%d), blocked on sem 0x%x\n", t, t->id, t->sem_blocking)); TRACE(("sem_interrupt_thread: called on thread %p (%d), blocked on sem 0x%x\n",
t, t->id, t->sem_blocking));
if (t->state != B_THREAD_WAITING || t->sem_blocking < 0) if (t->state != B_THREAD_WAITING || t->sem_blocking < 0)
return EINVAL; return B_BAD_VALUE;
if (!(t->sem_flags & B_CAN_INTERRUPT)) if (!(t->sem_flags & B_CAN_INTERRUPT))
return ERR_SEM_NOT_INTERRUPTABLE; return B_NOT_ALLOWED;
slot = t->sem_blocking % MAX_SEMS; slot = t->sem_blocking % MAX_SEMS;
@@ -832,7 +836,7 @@ sem_interrupt_thread(struct thread *t)
} }
wakeup_queue.head = wakeup_queue.tail = NULL; wakeup_queue.head = wakeup_queue.tail = NULL;
if (remove_thread_from_sem(t, &gSems[slot], &wakeup_queue, EINTR) == ERR_NOT_FOUND) if (remove_thread_from_sem(t, &gSems[slot], &wakeup_queue, EINTR) != B_OK)
panic("sem_interrupt_thread: thread 0x%lx not found in sem 0x%lx's wait queue\n", t->id, t->sem_blocking); panic("sem_interrupt_thread: thread 0x%lx not found in sem 0x%lx's wait queue\n", t->id, t->sem_blocking);
RELEASE_SEM_LOCK(gSems[slot]); RELEASE_SEM_LOCK(gSems[slot]);
@@ -858,7 +862,8 @@ remove_thread_from_sem(struct thread *t, struct sem_entry *sem, struct thread_qu
// remove the thread from the queue and place it in the supplied queue // remove the thread from the queue and place it in the supplied queue
t1 = thread_dequeue_id(&sem->u.used.q, t->id); t1 = thread_dequeue_id(&sem->u.used.q, t->id);
if (t != t1) if (t != t1)
return ERR_NOT_FOUND; return B_ENTRY_NOT_FOUND;
sem->u.used.count += t->sem_acquire_count; sem->u.used.count += t->sem_acquire_count;
t->state = t->next_state = B_THREAD_READY; t->state = t->next_state = B_THREAD_READY;
t->sem_errcode = sem_errcode; t->sem_errcode = sem_errcode;