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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 1.35 2004/06/04 20:35:36 dillon 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>
65 #include <sys/kern_syscall.h>
66 #include <sys/upcall.h>
70 #include <vm/vm_param.h>
73 #include <vm/vm_map.h>
74 #include <vm/vm_zone.h>
75 #include <vm/vm_extern.h>
78 /* Required to be non-static for SysVR4 emulator */
79 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
81 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
84 * callout list for things to do at exit time
88 TAILQ_ENTRY(exitlist) next;
91 TAILQ_HEAD(exit_list_head, exitlist);
92 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
98 * SYS_EXIT_ARGS(int rval)
101 sys_exit(struct sys_exit_args *uap)
103 exit1(W_EXITCODE(uap->rval, 0));
108 * Exit: deallocate address space and other resources, change proc state
109 * to zombie, and unlink proc from allproc and parent's lists. Save exit
110 * status and rusage for wait(). Check for child processes and orphan them.
115 struct proc *p = curproc;
122 printf("init died (signal %d, exit %d)\n",
123 WTERMSIG(rv), WEXITSTATUS(rv));
124 panic("Going nowhere without my init!");
127 sysmsg_rundown(p, 1);
128 caps_exit(p->p_thread);
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, 0, "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)
162 (*ep->function)(p->p_thread);
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 KKASSERT(p->p_numposixlocks == 0);
205 /* The next two chunks should probably be moved to vmspace_exit. */
209 * Release upcalls associated with this process
215 * Release user portion of address space.
216 * This releases references to vnodes,
217 * which could cause I/O if the file has been unlinked.
218 * Need to do this early enough that we can still sleep.
219 * Can't free the entire vmspace as the kernel stack
220 * may be mapped within that space also.
222 * Processes sharing the same vmspace may exit in one order, and
223 * get cleaned up by vmspace_exit() in a different order. The
224 * last exiting process to reach this point releases as much of
225 * the environment as it can, and the last process cleaned up
226 * by vmspace_exit() (which decrements exitingcnt) cleans up the
230 if (--vm->vm_refcnt == 0) {
232 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS,
234 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS,
238 if (SESS_LEADER(p)) {
239 struct session *sp = p->p_session;
243 * Controlling process.
244 * Signal foreground pgrp,
245 * drain controlling terminal
246 * and revoke access to controlling terminal.
248 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
249 if (sp->s_ttyp->t_pgrp)
250 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
251 (void) ttywait(sp->s_ttyp);
253 * The tty could have been revoked
257 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
263 * s_ttyp is not zero'd; we use this to indicate
264 * that the session once had a controlling terminal.
265 * (for logging and informational purposes)
270 fixjobc(p, p->p_pgrp, 0);
271 (void)acct_process(p);
276 p->p_traceflag = 0; /* don't trace the vrele() */
277 if ((vtmp = p->p_tracep) != NULL) {
283 * Release reference to text vnode
285 if ((vtmp = p->p_textvp) != NULL) {
291 * Once we set SZOMB the process can get reaped. The wait1 code
292 * will also wait for TDF_RUNNING to be cleared in the thread's flags,
293 * indicating that it has been completely switched out.
297 * Remove proc from allproc queue and pidhash chain.
298 * Place onto zombproc. Unlink from parent's child list.
300 LIST_REMOVE(p, p_list);
301 LIST_INSERT_HEAD(&zombproc, p, p_list);
304 LIST_REMOVE(p, p_hash);
306 q = LIST_FIRST(&p->p_children);
307 if (q) /* only need this if any child is S_ZOMB */
308 wakeup((caddr_t) initproc);
309 for (; q != 0; q = nq) {
310 nq = LIST_NEXT(q, p_sibling);
311 LIST_REMOVE(q, p_sibling);
312 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
313 q->p_pptr = initproc;
314 q->p_sigparent = SIGCHLD;
316 * Traced processes are killed
317 * since their existence means someone is screwing up.
319 if (q->p_flag & P_TRACED) {
320 q->p_flag &= ~P_TRACED;
326 * Save exit status and final rusage info, adding in child rusage
327 * info and self times.
330 *p->p_ru = p->p_stats->p_ru;
331 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
332 ruadd(p->p_ru, &p->p_stats->p_cru);
335 * notify interested parties of our demise.
337 KNOTE(&p->p_klist, NOTE_EXIT);
340 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
341 * flag set, notify process 1 instead (and hope it will handle
344 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) {
345 struct proc *pp = p->p_pptr;
346 proc_reparent(p, initproc);
348 * If this was the last child of our parent, notify
349 * parent, so in case he was wait(2)ing, he will
352 if (LIST_EMPTY(&pp->p_children))
356 if (p->p_sigparent && p->p_pptr != initproc) {
357 psignal(p->p_pptr, p->p_sigparent);
359 psignal(p->p_pptr, SIGCHLD);
362 wakeup((caddr_t)p->p_pptr);
364 /* move this to cpu_exit */
365 p->p_thread->td_pcb->pcb_saveacc.faddr = (float *)NULL;
368 * cpu_exit is responsible for clearing curproc, since
369 * it is heavily integrated with the thread/switching sequence.
371 * Other substructures are freed from wait().
373 if (--p->p_limit->p_refcnt == 0) {
374 FREE(p->p_limit, M_SUBPROC);
379 * Release the current user process designation on the process so
380 * the userland scheduler can work in someone else.
385 * Finally, call machine-dependent code to release the remaining
386 * resources including address space, the kernel stack and pcb.
387 * The address space is released by "vmspace_free(p->p_vmspace)";
388 * This is machine-dependent, as we may have to change stacks
389 * or ensure that the current one isn't reallocated before we
390 * finish. cpu_exit will end with a call to cpu_switch(), finishing
391 * our execution (pun intended).
397 wait4(struct wait_args *uap)
399 struct rusage rusage;
402 error = kern_wait(uap->pid, uap->status ? &status : NULL,
403 uap->options, uap->rusage ? &rusage : NULL, &uap->sysmsg_fds[0]);
405 if (error == 0 && uap->status)
406 error = copyout(&status, uap->status, sizeof(*uap->status));
407 if (error == 0 && uap->rusage)
408 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
415 * wait_args(int pid, int *status, int options, struct rusage *rusage)
418 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
420 struct thread *td = curthread;
421 struct proc *q = td->td_proc;
427 if (options &~ (WUNTRACED|WNOHANG|WLINUXCLONE))
431 LIST_FOREACH(p, &q->p_children, p_sibling) {
432 if (pid != WAIT_ANY &&
433 p->p_pid != pid && p->p_pgid != -pid)
436 /* This special case handles a kthread spawned by linux_clone
437 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions
438 * need to be able to distinguish between waiting on a process and
439 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD,
440 * and the WLINUXCLONE option signifies we want to wait for threads
443 if ((p->p_sigparent != SIGCHLD) ^ ((options & WLINUXCLONE) != 0))
447 if (p->p_stat == SZOMB) {
449 * The process's thread may still be in the middle
450 * of switching away, we can't rip its stack out from
451 * under it until TDF_RUNNING clears!
453 * YYY no wakeup occurs so we depend on the timeout.
455 if ((p->p_thread->td_flags & TDF_RUNNING) != 0) {
456 tsleep(p->p_thread, 0, "reap", 1);
461 * Other kernel threads may be in the middle of
462 * accessing the proc. For example, kern/kern_proc.c
463 * could be blocked writing proc data to a sysctl.
464 * At the moment, if this occurs, we are not woken
465 * up and rely on a one-second retry.
469 tsleep(p, 0, "reap2", hz);
471 lwkt_wait_free(p->p_thread);
474 * Charge the parent for the child's change in
475 * estimated cpu as of when the child exits to
476 * account for batch scripts, large make's, etc.
479 if (p->p_estcpu > p->p_estcpu_fork) {
480 q->p_estcpu = ESTCPULIM(q->p_estcpu +
481 p->p_estcpu - p->p_estcpu_fork);
485 /* Take care of our return values. */
488 *status = p->p_xstat;
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 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 || options & WUNTRACED)) {
546 p->p_flag |= P_WAITED;
550 *status = W_STOPCODE(p->p_xstat);
551 /* Zero rusage so we get something consistent. */
553 bzero(rusage, sizeof(rusage));
559 if (options & WNOHANG) {
563 error = tsleep((caddr_t)q, PCATCH, "wait", 0);
570 * make process 'parent' the new parent of process 'child'.
573 proc_reparent(child, parent)
578 if (child->p_pptr == parent)
581 LIST_REMOVE(child, p_sibling);
582 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
583 child->p_pptr = parent;
587 * The next two functions are to handle adding/deleting items on the
591 * Take the arguments given and put them onto the exit callout list,
592 * However first make sure that it's not already there.
593 * returns 0 on success.
598 exitlist_fn function;
603 /* Be noisy if the programmer has lost track of things */
604 if (rm_at_exit(function))
605 printf("WARNING: exit callout entry (%p) already present\n",
608 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
611 ep->function = function;
612 TAILQ_INSERT_TAIL(&exit_list, ep, next);
617 * Scan the exit callout list for the given item and remove it.
618 * Returns the number of items removed (0 or 1)
622 exitlist_fn function;
626 TAILQ_FOREACH(ep, &exit_list, next) {
627 if (ep->function == function) {
628 TAILQ_REMOVE(&exit_list, ep, next);
636 void check_sigacts (void)
638 struct proc *p = curproc;
642 if (p->p_procsig->ps_refcnt == 1 &&
643 p->p_sigacts != &p->p_addr->u_sigacts) {
646 p->p_addr->u_sigacts = *pss;
647 p->p_sigacts = &p->p_addr->u_sigacts;
649 FREE(pss, M_SUBPROC);