int
kern_thr_exit(struct thread *td)
{
struct proc *p;
p = td->td_proc;
rw_wlock(&tidhash_lock);
PROC_LOCK(p);
if (p->p_numthreads != 1) {
racct_sub(p, RACCT_NTHR, 1);
LIST_REMOVE(td, td_hash);
rw_wunlock(&tidhash_lock);
tdsigcleanup(td);
umtx_thread_exit(td);
PROC_SLOCK(p);
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
/*
* Ignore attempts to shut down last thread in the proc. This
* will actually call _exit(2) in the usermode trampoline when
* it returns.
*/
PROC_UNLOCK(p);
rw_wunlock(&tidhash_lock);
return (0);
}
int
kern_thr_exit(struct thread *td)
{
struct proc *p;
p = td->td_proc;
/*
* If all of the threads in a process call this routine to
* exit (e.g. all threads call pthread_exit()), exactly one
* thread should return to the caller to terminate the process
* instead of the thread.
*
* Checking p_numthreads alone is not sufficient since threads
* might be committed to terminating while the PROC_LOCK is
* dropped in either ptracestop() or while removing this thread
* from the tidhash. Instead, the p_pendingexits field holds
* the count of threads in either of those states and a thread
* is considered the "last" thread if all of the other threads
* in a process are already terminating.
*/
PROC_LOCK(p);
if (p->p_numthreads == p->p_pendingexits + 1) {
/*
* Ignore attempts to shut down last thread in the
* proc. This will actually call _exit(2) in the
* usermode trampoline when it returns.
*/
PROC_UNLOCK(p);
return (0);
}
p->p_pendingexits++;
td->td_dbgflags |= TDB_EXIT;
if (p->p_flag & P_TRACED && p->p_flag2 & P2_LWP_EVENTS)
ptracestop(td, SIGTRAP);
PROC_UNLOCK(p);
tidhash_remove(td);
PROC_LOCK(p);
p->p_pendingexits--;
/*
* The check above should prevent all other threads from this
* process from exiting while the PROC_LOCK is dropped, so
* there must be at least one other thread other than the
* current thread.
*/
KASSERT(p->p_numthreads > 1, ("too few threads"));
racct_sub(p, RACCT_NTHR, 1);
tdsigcleanup(td);
umtx_thread_exit(td);
PROC_SLOCK(p);
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
int
sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
/* long *state */
{
struct proc *p;
p = td->td_proc;
/* Signal userland that it can free the stack. */
if ((void *)uap->state != NULL) {
suword_lwpid(uap->state, 1);
kern_umtx_wake(td, uap->state, INT_MAX, 0);
}
rw_wlock(&tidhash_lock);
PROC_LOCK(p);
if (p->p_numthreads != 1) {
racct_sub(p, RACCT_NTHR, 1);
LIST_REMOVE(td, td_hash);
rw_wunlock(&tidhash_lock);
tdsigcleanup(td);
PROC_SLOCK(p);
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
/*
* Ignore attempts to shut down last thread in the proc. This
* will actually call _exit(2) in the usermode trampoline when
* it returns.
*/
PROC_UNLOCK(p);
rw_wunlock(&tidhash_lock);
return (0);
}
