/*
* Cause the current thread to exit.
*
* We clean up the parts of the thread structure we don't actually
* need to run right away. The rest has to wait until thread_destroy
* gets called from exorcise().
*/
void
thread_exit(int exitcode)
{
DEBUG(DB_THREADS,"Thread %s exiting with %d",
curthread->t_name, exitcode);
/* ASST1: Let the pid management system know this thread is done. */
pid_setexited(curthread->t_pid, exitcode);
if (curthread->t_stack != NULL) {
/*
* Check the magic number we put on the bottom end of
* the stack in thread_fork. If these assertions go
* off, it most likely means you overflowed your stack
* at some point, which can cause all kinds of
* mysterious other things to happen.
*/
assert(curthread->t_stack[0] == (char)0xae);
assert(curthread->t_stack[1] == (char)0x11);
assert(curthread->t_stack[2] == (char)0xda);
assert(curthread->t_stack[3] == (char)0x33);
}
splhigh();
if (curthread->t_vmspace) {
/*
* Do this carefully to avoid race condition with
* context switch code.
*/
struct addrspace *as = curthread->t_vmspace;
curthread->t_vmspace = NULL;
as_destroy(as);
}
if (curthread->t_cwd) {
VOP_DECREF(curthread->t_cwd);
curthread->t_cwd = NULL;
}
/* A3 SETUP */
if (curthread->t_filetable) {
filetable_destroy(curthread->t_filetable);
/* set it back to NULL so it can be initialized again */
curthread->t_filetable = NULL;
}
/* END A3 SETUP */
assert(numthreads>0);
numthreads--;
mi_switch(S_ZOMB);
panic("Thread came back from the dead!\n");
}
/*
* Destroy a proc structure.
*
* Note: nothing currently calls this. Your wait/exit code will
* probably want to do so.
*/
void
proc_destroy(struct proc *proc)
{
/*
* You probably want to destroy and null out much of the
* process (particularly the address space) at exit time if
* your wait/exit design calls for the process structure to
* hang around beyond process exit. Some wait/exit designs
* do, some don't.
*/
KASSERT(proc != NULL);
KASSERT(proc != kproc);
/*
* We don't take p_lock in here because we must have the only
* reference to this structure. (Otherwise it would be
* incorrect to destroy it.)
*/
/* VFS fields */
if (proc->p_cwd) {
VOP_DECREF(proc->p_cwd);
proc->p_cwd = NULL;
}
if (proc->p_filetable) {
filetable_destroy(proc->p_filetable);
proc->p_filetable = NULL;
}
/* VM fields */
if (proc->p_addrspace) {
/*
* If p is the current process, remove it safely from
* p_addrspace before destroying it. This makes sure
* we don't try to activate the address space while
* it's being destroyed.
*
* Also explicitly deactivate, because setting the
* address space to NULL won't necessarily do that.
*
* (When the address space is NULL, it means the
* process is kernel-only; in that case it is normally
* ok if the MMU and MMU- related data structures
* still refer to the address space of the last
* process that had one. Then you save work if that
* process is the next one to run, which isn't
* uncommon. However, here we're going to destroy the
* address space, so we need to make sure that nothing
* in the VM system still refers to it.)
*
* The call to as_deactivate() must come after we
* clear the address space, or a timer interrupt might
* reactivate the old address space again behind our
* back.
*
* If p is not the current process, still remove it
* from p_addrspace before destroying it as a
* precaution. Note that if p is not the current
* process, in order to be here p must either have
* never run (e.g. cleaning up after fork failed) or
* have finished running and exited. It is quite
* incorrect to destroy the proc structure of some
* random other process while it's still running...
*/
struct addrspace *as;
if (proc == curproc) {
as = proc_setas(NULL);
as_deactivate();
}
else {
as = proc->p_addrspace;
proc->p_addrspace = NULL;
}
as_destroy(as);
}
threadarray_cleanup(&proc->p_threads);
spinlock_cleanup(&proc->p_lock);
kfree(proc->p_name);
kfree(proc);
}
