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38 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
39 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $
40 * $DragonFly: src/sys/kern/kern_exit.c,v 1.23 2003/08/26 21:09:02 rob Exp $
43 #include "opt_compat.h"
44 #include "opt_ktrace.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/sysproto.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
52 #include <sys/pioctl.h>
55 #include <sys/vnode.h>
56 #include <sys/resourcevar.h>
57 #include <sys/signalvar.h>
58 #include <sys/ptrace.h>
59 #include <sys/acct.h> /* for acct_process() function prototype */
60 #include <sys/filedesc.h>
67 #include <vm/vm_param.h>
70 #include <vm/vm_map.h>
71 #include <vm/vm_zone.h>
72 #include <vm/vm_extern.h>
75 /* Required to be non-static for SysVR4 emulator */
76 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
78 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
80 static int wait1 (struct wait_args *, int);
83 * callout list for things to do at exit time
87 TAILQ_ENTRY(exitlist) next;
90 TAILQ_HEAD(exit_list_head, exitlist);
91 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
97 * SYS_EXIT_ARGS(int rval)
100 sys_exit(struct sys_exit_args *uap)
102 exit1(W_EXITCODE(uap->rval, 0));
107 * Exit: deallocate address space and other resources, change proc state
108 * to zombie, and unlink proc from allproc and parent's lists. Save exit
109 * status and rusage for wait(). Check for child processes and orphan them.
114 struct proc *p = curproc;
121 printf("init died (signal %d, exit %d)\n",
122 WTERMSIG(rv), WEXITSTATUS(rv));
123 panic("Going nowhere without my init!");
128 /* are we a task leader? */
129 if(p == p->p_leader) {
130 struct kill_args killArgs;
131 killArgs.signum = SIGKILL;
134 killArgs.pid = q->p_pid;
136 * The interface for kill is better
137 * than the internal signal
144 tsleep((caddr_t)p, 0, "exit1", 0);
150 STOPEVENT(p, S_EXIT, rv);
151 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */
154 * Check if any loadable modules need anything done at process exit.
155 * e.g. SYSV IPC stuff
156 * XXX what if one of these generates an error?
158 TAILQ_FOREACH(ep, &exit_list, next)
159 (*ep->function)(p->p_thread);
161 if (p->p_flag & P_PROFIL)
163 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
166 * If parent is waiting for us to exit or exec,
167 * P_PPWAIT is set; we will wakeup the parent below.
169 p->p_flag &= ~(P_TRACED | P_PPWAIT);
170 p->p_flag |= P_WEXIT;
171 SIGEMPTYSET(p->p_siglist);
172 if (timevalisset(&p->p_realtimer.it_value))
173 untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
176 * Reset any sigio structures pointing to us as a result of
177 * F_SETOWN with our pid.
179 funsetownlst(&p->p_sigiolst);
182 * Close open files and release open-file table.
187 if(p->p_leader->p_peers) {
189 while(q->p_peers != p)
191 q->p_peers = p->p_peers;
192 wakeup((caddr_t)p->p_leader);
196 * XXX Shutdown SYSV semaphores
200 /* The next two chunks should probably be moved to vmspace_exit. */
203 * Release user portion of address space.
204 * This releases references to vnodes,
205 * which could cause I/O if the file has been unlinked.
206 * Need to do this early enough that we can still sleep.
207 * Can't free the entire vmspace as the kernel stack
208 * may be mapped within that space also.
210 * Processes sharing the same vmspace may exit in one order, and
211 * get cleaned up by vmspace_exit() in a different order. The
212 * last exiting process to reach this point releases as much of
213 * the environment as it can, and the last process cleaned up
214 * by vmspace_exit() (which decrements exitingcnt) cleans up the
218 if (--vm->vm_refcnt == 0) {
220 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS,
222 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS,
226 if (SESS_LEADER(p)) {
227 struct session *sp = p->p_session;
231 * Controlling process.
232 * Signal foreground pgrp,
233 * drain controlling terminal
234 * and revoke access to controlling terminal.
236 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
237 if (sp->s_ttyp->t_pgrp)
238 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
239 (void) ttywait(sp->s_ttyp);
241 * The tty could have been revoked
245 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
251 * s_ttyp is not zero'd; we use this to indicate
252 * that the session once had a controlling terminal.
253 * (for logging and informational purposes)
258 fixjobc(p, p->p_pgrp, 0);
259 (void)acct_process(p);
264 p->p_traceflag = 0; /* don't trace the vrele() */
265 if ((vtmp = p->p_tracep) != NULL) {
271 * Release reference to text vnode
273 if ((vtmp = p->p_textvp) != NULL) {
279 * Once we set SZOMB the process can get reaped. The wait1 code
280 * will also wait for TDF_RUNNING to be cleared in the thread's flags,
281 * indicating that it has been completely switched out.
285 * Remove proc from allproc queue and pidhash chain.
286 * Place onto zombproc. Unlink from parent's child list.
288 LIST_REMOVE(p, p_list);
289 LIST_INSERT_HEAD(&zombproc, p, p_list);
292 LIST_REMOVE(p, p_hash);
294 q = LIST_FIRST(&p->p_children);
295 if (q) /* only need this if any child is S_ZOMB */
296 wakeup((caddr_t) initproc);
297 for (; q != 0; q = nq) {
298 nq = LIST_NEXT(q, p_sibling);
299 LIST_REMOVE(q, p_sibling);
300 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
301 q->p_pptr = initproc;
302 q->p_sigparent = SIGCHLD;
304 * Traced processes are killed
305 * since their existence means someone is screwing up.
307 if (q->p_flag & P_TRACED) {
308 q->p_flag &= ~P_TRACED;
314 * Save exit status and final rusage info, adding in child rusage
315 * info and self times.
318 *p->p_ru = p->p_stats->p_ru;
319 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
320 ruadd(p->p_ru, &p->p_stats->p_cru);
323 * notify interested parties of our demise.
325 KNOTE(&p->p_klist, NOTE_EXIT);
328 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
329 * flag set, notify process 1 instead (and hope it will handle
332 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) {
333 struct proc *pp = p->p_pptr;
334 proc_reparent(p, initproc);
336 * If this was the last child of our parent, notify
337 * parent, so in case he was wait(2)ing, he will
340 if (LIST_EMPTY(&pp->p_children))
344 if (p->p_sigparent && p->p_pptr != initproc) {
345 psignal(p->p_pptr, p->p_sigparent);
347 psignal(p->p_pptr, SIGCHLD);
350 wakeup((caddr_t)p->p_pptr);
352 /* move this to cpu_exit */
353 p->p_thread->td_pcb->pcb_saveacc.faddr = (float *)NULL;
356 * cpu_exit is responsible for clearing curproc, since
357 * it is heavily integrated with the thread/switching sequence.
359 * Other substructures are freed from wait().
361 if (--p->p_limit->p_refcnt == 0) {
362 FREE(p->p_limit, M_SUBPROC);
367 * Release the P_CURPROC designation on the process so the userland
368 * scheduler can work in someone else.
373 * Finally, call machine-dependent code to release the remaining
374 * resources including address space, the kernel stack and pcb.
375 * The address space is released by "vmspace_free(p->p_vmspace)";
376 * This is machine-dependent, as we may have to change stacks
377 * or ensure that the current one isn't reallocated before we
378 * finish. cpu_exit will end with a call to cpu_switch(), finishing
379 * our execution (pun intended).
388 * owait_args(int dummy)
391 owait(struct owait_args *uap)
399 return (wait1(&w, 1));
401 #endif /* COMPAT_43 */
404 wait4(struct wait_args *uap)
406 return (wait1(uap, 0));
412 * wait_args(int pid, int *status, int options, struct rusage *rusage)
415 wait1(struct wait_args *uap, int compat)
417 struct proc *q = curproc;
419 int status, nfound, error;
422 uap->pid = -q->p_pgid;
423 if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE))
427 LIST_FOREACH(p, &q->p_children, p_sibling) {
428 if (uap->pid != WAIT_ANY &&
429 p->p_pid != uap->pid && p->p_pgid != -uap->pid)
432 /* This special case handles a kthread spawned by linux_clone
433 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions
434 * need to be able to distinguish between waiting on a process and
435 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD,
436 * and the WLINUXCLONE option signifies we want to wait for threads
439 if ((p->p_sigparent != SIGCHLD) ^ ((uap->options & WLINUXCLONE) != 0))
443 if (p->p_stat == SZOMB) {
445 * The process's thread may still be in the middle
446 * of switching away, we can't rip its stack out from
447 * under it until TDF_RUNNING clears!
449 * YYY no wakeup occurs so we depend on the timeout.
451 if ((p->p_thread->td_flags & TDF_RUNNING) != 0) {
452 tsleep(p->p_thread, 0, "reap", 1);
457 * Other kernel threads may be in the middle of
458 * accessing the proc. For example, kern/kern_proc.c
459 * could be blocked writing proc data to a sysctl.
460 * At the moment, if this occurs, we are not woken
461 * up and rely on a one-second retry.
464 printf("Diagnostic: waiting for p_lock\n");
466 tsleep(p, 0, "reap2", hz);
468 lwkt_wait_free(p->p_thread);
470 /* charge childs scheduling cpu usage to parent */
471 if (curproc->p_pid != 1) {
473 ESTCPULIM(curproc->p_estcpu + p->p_estcpu);
476 uap->sysmsg_fds[0] = p->p_pid;
479 uap->sysmsg_fds[1] = p->p_xstat;
483 status = p->p_xstat; /* convert to int */
484 if ((error = copyout((caddr_t)&status,
485 (caddr_t)uap->status, sizeof(status))))
488 if (uap->rusage && (error = copyout((caddr_t)p->p_ru,
489 (caddr_t)uap->rusage, sizeof (struct rusage))))
492 * If we got the child via a ptrace 'attach',
493 * we need to give it back to the old parent.
495 if (p->p_oppid && (t = pfind(p->p_oppid))) {
503 ruadd(&q->p_stats->p_cru, p->p_ru);
504 FREE(p->p_ru, M_ZOMBIE);
508 * Decrement the count of procs running with this uid.
510 (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
513 * Free up credentials.
519 * Remove unused arguments
521 if (p->p_args && --p->p_args->ar_ref == 0)
522 FREE(p->p_args, M_PARGS);
525 * Finally finished with old proc entry.
526 * Unlink it from its process group and free it.
529 LIST_REMOVE(p, p_list); /* off zombproc */
530 LIST_REMOVE(p, p_sibling);
532 if (--p->p_procsig->ps_refcnt == 0) {
533 if (p->p_sigacts != &p->p_addr->u_sigacts)
534 FREE(p->p_sigacts, M_SUBPROC);
535 FREE(p->p_procsig, M_SUBPROC);
544 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 &&
545 (p->p_flag & P_TRACED || uap->options & WUNTRACED)) {
546 p->p_flag |= P_WAITED;
547 uap->sysmsg_fds[0] = p->p_pid;
550 uap->sysmsg_fds[1] = W_STOPCODE(p->p_xstat);
555 status = W_STOPCODE(p->p_xstat);
556 error = copyout((caddr_t)&status,
557 (caddr_t)uap->status, sizeof(status));
565 if (uap->options & WNOHANG) {
566 uap->sysmsg_fds[0] = 0;
569 if ((error = tsleep((caddr_t)q, PCATCH, "wait", 0)))
575 * make process 'parent' the new parent of process 'child'.
578 proc_reparent(child, parent)
583 if (child->p_pptr == parent)
586 LIST_REMOVE(child, p_sibling);
587 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
588 child->p_pptr = parent;
592 * The next two functions are to handle adding/deleting items on the
596 * Take the arguments given and put them onto the exit callout list,
597 * However first make sure that it's not already there.
598 * returns 0 on success.
603 exitlist_fn function;
608 /* Be noisy if the programmer has lost track of things */
609 if (rm_at_exit(function))
610 printf("WARNING: exit callout entry (%p) already present\n",
613 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
616 ep->function = function;
617 TAILQ_INSERT_TAIL(&exit_list, ep, next);
622 * Scan the exit callout list for the given item and remove it.
623 * Returns the number of items removed (0 or 1)
627 exitlist_fn function;
631 TAILQ_FOREACH(ep, &exit_list, next) {
632 if (ep->function == function) {
633 TAILQ_REMOVE(&exit_list, ep, next);
641 void check_sigacts (void)
643 struct proc *p = curproc;
647 if (p->p_procsig->ps_refcnt == 1 &&
648 p->p_sigacts != &p->p_addr->u_sigacts) {
651 p->p_addr->u_sigacts = *pss;
652 p->p_sigacts = &p->p_addr->u_sigacts;
654 FREE(pss, M_SUBPROC);