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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 $
42 #include "opt_compat.h"
43 #include "opt_ktrace.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/sysproto.h>
48 #include <sys/kernel.h>
49 #include <sys/malloc.h>
51 #include <sys/pioctl.h>
54 #include <sys/vnode.h>
55 #include <sys/resourcevar.h>
56 #include <sys/signalvar.h>
57 #include <sys/ptrace.h>
58 #include <sys/acct.h> /* for acct_process() function prototype */
59 #include <sys/filedesc.h>
66 #include <vm/vm_param.h>
69 #include <vm/vm_map.h>
70 #include <vm/vm_zone.h>
71 #include <vm/vm_extern.h>
74 /* Required to be non-static for SysVR4 emulator */
75 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
77 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
79 static int wait1 __P((struct proc *, struct wait_args *, int));
82 * callout list for things to do at exit time
86 TAILQ_ENTRY(exitlist) next;
89 TAILQ_HEAD(exit_list_head, exitlist);
90 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
99 struct sys_exit_args /* {
104 exit1(p, W_EXITCODE(uap->rval, 0));
109 * Exit: deallocate address space and other resources, change proc state
110 * to zombie, and unlink proc from allproc and parent's lists. Save exit
111 * status and rusage for wait(). Check for child processes and orphan them.
115 register struct proc *p;
118 register struct proc *q, *nq;
119 register struct vmspace *vm;
124 printf("init died (signal %d, exit %d)\n",
125 WTERMSIG(rv), WEXITSTATUS(rv));
126 panic("Going nowhere without my init!");
131 /* are we a task leader? */
132 if(p == p->p_leader) {
133 struct kill_args killArgs;
134 killArgs.signum = SIGKILL;
137 killArgs.pid = q->p_pid;
139 * The interface for kill is better
140 * than the internal signal
147 tsleep((caddr_t)p, PWAIT, "exit1", 0);
153 STOPEVENT(p, S_EXIT, rv);
154 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */
157 * Check if any loadable modules need anything done at process exit.
158 * e.g. SYSV IPC stuff
159 * XXX what if one of these generates an error?
161 TAILQ_FOREACH(ep, &exit_list, next)
164 if (p->p_flag & P_PROFIL)
166 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
169 * If parent is waiting for us to exit or exec,
170 * P_PPWAIT is set; we will wakeup the parent below.
172 p->p_flag &= ~(P_TRACED | P_PPWAIT);
173 p->p_flag |= P_WEXIT;
174 SIGEMPTYSET(p->p_siglist);
175 if (timevalisset(&p->p_realtimer.it_value))
176 untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
179 * Reset any sigio structures pointing to us as a result of
180 * F_SETOWN with our pid.
182 funsetownlst(&p->p_sigiolst);
185 * Close open files and release open-file table.
190 if(p->p_leader->p_peers) {
192 while(q->p_peers != p)
194 q->p_peers = p->p_peers;
195 wakeup((caddr_t)p->p_leader);
199 * XXX Shutdown SYSV semaphores
203 /* The next two chunks should probably be moved to vmspace_exit. */
206 * Release user portion of address space.
207 * This releases references to vnodes,
208 * which could cause I/O if the file has been unlinked.
209 * Need to do this early enough that we can still sleep.
210 * Can't free the entire vmspace as the kernel stack
211 * may be mapped within that space also.
213 * Processes sharing the same vmspace may exit in one order, and
214 * get cleaned up by vmspace_exit() in a different order. The
215 * last exiting process to reach this point releases as much of
216 * the environment as it can, and the last process cleaned up
217 * by vmspace_exit() (which decrements exitingcnt) cleans up the
221 if (--vm->vm_refcnt == 0) {
224 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS,
226 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS,
230 if (SESS_LEADER(p)) {
231 register struct session *sp = p->p_session;
235 * Controlling process.
236 * Signal foreground pgrp,
237 * drain controlling terminal
238 * and revoke access to controlling terminal.
240 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
241 if (sp->s_ttyp->t_pgrp)
242 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
243 (void) ttywait(sp->s_ttyp);
245 * The tty could have been revoked
249 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
255 * s_ttyp is not zero'd; we use this to indicate
256 * that the session once had a controlling terminal.
257 * (for logging and informational purposes)
262 fixjobc(p, p->p_pgrp, 0);
263 (void)acct_process(p);
268 p->p_traceflag = 0; /* don't trace the vrele() */
269 if ((vtmp = p->p_tracep) != NULL) {
275 * Release reference to text vnode
277 if ((vtmp = p->p_textvp) != NULL) {
283 * Remove proc from allproc queue and pidhash chain.
284 * Place onto zombproc. Unlink from parent's child list.
286 LIST_REMOVE(p, p_list);
287 LIST_INSERT_HEAD(&zombproc, p, p_list);
290 LIST_REMOVE(p, p_hash);
292 q = LIST_FIRST(&p->p_children);
293 if (q) /* only need this if any child is S_ZOMB */
294 wakeup((caddr_t) initproc);
295 for (; q != 0; q = nq) {
296 nq = LIST_NEXT(q, p_sibling);
297 LIST_REMOVE(q, p_sibling);
298 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
299 q->p_pptr = initproc;
300 q->p_sigparent = SIGCHLD;
302 * Traced processes are killed
303 * since their existence means someone is screwing up.
305 if (q->p_flag & P_TRACED) {
306 q->p_flag &= ~P_TRACED;
312 * Save exit status and final rusage info, adding in child rusage
313 * info and self times.
316 *p->p_ru = p->p_stats->p_ru;
317 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
318 ruadd(p->p_ru, &p->p_stats->p_cru);
321 * Pretend that an mi_switch() to the next process occurs now. We
322 * must set `switchtime' directly since we will call cpu_switch()
323 * directly. Set it now so that the rest of the exit time gets
324 * counted somewhere if possible.
326 microuptime(&switchtime);
330 * notify interested parties of our demise.
332 KNOTE(&p->p_klist, NOTE_EXIT);
335 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
336 * flag set, notify process 1 instead (and hope it will handle
339 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) {
340 struct proc *pp = p->p_pptr;
341 proc_reparent(p, initproc);
343 * If this was the last child of our parent, notify
344 * parent, so in case he was wait(2)ing, he will
347 if (LIST_EMPTY(&pp->p_children))
351 if (p->p_sigparent && p->p_pptr != initproc) {
352 psignal(p->p_pptr, p->p_sigparent);
354 psignal(p->p_pptr, SIGCHLD);
357 wakeup((caddr_t)p->p_pptr);
359 /* move this to cpu_exit */
360 p->p_addr->u_pcb.pcb_savacc.faddr = (float *)NULL;
363 * Clear curproc after we've done all operations
364 * that could block, and before tearing down the rest
365 * of the process state that might be used from clock, etc.
366 * Also, can't clear curproc while we're still runnable,
367 * as we're not on a run queue (we are current, just not
368 * a proper proc any longer!).
370 * Other substructures are freed from wait().
373 if (--p->p_limit->p_refcnt == 0) {
374 FREE(p->p_limit, M_SUBPROC);
379 * Finally, call machine-dependent code to release the remaining
380 * resources including address space, the kernel stack and pcb.
381 * The address space is released by "vmspace_free(p->p_vmspace)";
382 * This is machine-dependent, as we may have to change stacks
383 * or ensure that the current one isn't reallocated before we
384 * finish. cpu_exit will end with a call to cpu_switch(), finishing
385 * our execution (pun intended).
394 register struct owait_args /* {
404 return (wait1(p, &w, 1));
406 #endif /* COMPAT_43 */
411 struct wait_args *uap;
414 return (wait1(p, uap, 0));
418 wait1(q, uap, compat)
419 register struct proc *q;
420 register struct wait_args /* {
424 struct rusage *rusage;
429 register struct proc *p, *t;
433 uap->pid = -q->p_pgid;
434 if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE))
438 LIST_FOREACH(p, &q->p_children, p_sibling) {
439 if (uap->pid != WAIT_ANY &&
440 p->p_pid != uap->pid && p->p_pgid != -uap->pid)
443 /* This special case handles a kthread spawned by linux_clone
444 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions
445 * need to be able to distinguish between waiting on a process and
446 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD,
447 * and the WLINUXCLONE option signifies we want to wait for threads
450 if ((p->p_sigparent != SIGCHLD) ^ ((uap->options & WLINUXCLONE) != 0))
454 if (p->p_stat == SZOMB) {
455 /* charge childs scheduling cpu usage to parent */
456 if (curproc->p_pid != 1) {
458 ESTCPULIM(curproc->p_estcpu + p->p_estcpu);
461 q->p_retval[0] = p->p_pid;
464 q->p_retval[1] = p->p_xstat;
468 status = p->p_xstat; /* convert to int */
469 if ((error = copyout((caddr_t)&status,
470 (caddr_t)uap->status, sizeof(status))))
473 if (uap->rusage && (error = copyout((caddr_t)p->p_ru,
474 (caddr_t)uap->rusage, sizeof (struct rusage))))
477 * If we got the child via a ptrace 'attach',
478 * we need to give it back to the old parent.
480 if (p->p_oppid && (t = pfind(p->p_oppid))) {
488 ruadd(&q->p_stats->p_cru, p->p_ru);
489 FREE(p->p_ru, M_ZOMBIE);
493 * Decrement the count of procs running with this uid.
495 (void)chgproccnt(p->p_cred->p_uidinfo, -1, 0);
498 * Free up credentials.
500 if (--p->p_cred->p_refcnt == 0) {
502 uifree(p->p_cred->p_uidinfo);
503 FREE(p->p_cred, M_SUBPROC);
508 * Destroy empty prisons
510 if (p->p_prison && !--p->p_prison->pr_ref) {
511 if (p->p_prison->pr_linux != NULL)
512 FREE(p->p_prison->pr_linux, M_PRISON);
513 FREE(p->p_prison, M_PRISON);
517 * Remove unused arguments
519 if (p->p_args && --p->p_args->ar_ref == 0)
520 FREE(p->p_args, M_PARGS);
523 * Finally finished with old proc entry.
524 * Unlink it from its process group and free it.
527 LIST_REMOVE(p, p_list); /* off zombproc */
528 LIST_REMOVE(p, p_sibling);
530 if (--p->p_procsig->ps_refcnt == 0) {
531 if (p->p_sigacts != &p->p_addr->u_sigacts)
532 FREE(p->p_sigacts, M_SUBPROC);
533 FREE(p->p_procsig, M_SUBPROC);
538 * Give machine-dependent layer a chance
539 * to free anything that cpu_exit couldn't
540 * release while still running in process context.
547 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 &&
548 (p->p_flag & P_TRACED || uap->options & WUNTRACED)) {
549 p->p_flag |= P_WAITED;
550 q->p_retval[0] = p->p_pid;
553 q->p_retval[1] = W_STOPCODE(p->p_xstat);
558 status = W_STOPCODE(p->p_xstat);
559 error = copyout((caddr_t)&status,
560 (caddr_t)uap->status, sizeof(status));
568 if (uap->options & WNOHANG) {
572 if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)))
578 * make process 'parent' the new parent of process 'child'.
581 proc_reparent(child, parent)
582 register struct proc *child;
583 register struct proc *parent;
586 if (child->p_pptr == parent)
589 LIST_REMOVE(child, p_sibling);
590 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
591 child->p_pptr = parent;
595 * The next two functions are to handle adding/deleting items on the
599 * Take the arguments given and put them onto the exit callout list,
600 * However first make sure that it's not already there.
601 * returns 0 on success.
606 exitlist_fn function;
611 /* Be noisy if the programmer has lost track of things */
612 if (rm_at_exit(function))
613 printf("WARNING: exit callout entry (%p) already present\n",
616 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
619 ep->function = function;
620 TAILQ_INSERT_TAIL(&exit_list, ep, next);
625 * Scan the exit callout list for the given item and remove it.
626 * Returns the number of items removed (0 or 1)
630 exitlist_fn function;
634 TAILQ_FOREACH(ep, &exit_list, next) {
635 if (ep->function == function) {
636 TAILQ_REMOVE(&exit_list, ep, next);
644 void check_sigacts (void)
646 struct proc *p = curproc;
650 if (p->p_procsig->ps_refcnt == 1 &&
651 p->p_sigacts != &p->p_addr->u_sigacts) {
654 p->p_addr->u_sigacts = *pss;
655 p->p_sigacts = &p->p_addr->u_sigacts;
657 FREE(pss, M_SUBPROC);