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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 1.28 2003/11/04 04:17:37 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>
68 #include <vm/vm_param.h>
71 #include <vm/vm_map.h>
72 #include <vm/vm_zone.h>
73 #include <vm/vm_extern.h>
76 /* Required to be non-static for SysVR4 emulator */
77 MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status");
79 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
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);
96 * SYS_EXIT_ARGS(int rval)
99 sys_exit(struct sys_exit_args *uap)
101 exit1(W_EXITCODE(uap->rval, 0));
106 * Exit: deallocate address space and other resources, change proc state
107 * to zombie, and unlink proc from allproc and parent's lists. Save exit
108 * status and rusage for wait(). Check for child processes and orphan them.
113 struct proc *p = curproc;
120 printf("init died (signal %d, exit %d)\n",
121 WTERMSIG(rv), WEXITSTATUS(rv));
122 panic("Going nowhere without my init!");
127 /* are we a task leader? */
128 if(p == p->p_leader) {
129 struct kill_args killArgs;
130 killArgs.signum = SIGKILL;
133 killArgs.pid = q->p_pid;
135 * The interface for kill is better
136 * than the internal signal
143 tsleep((caddr_t)p, 0, "exit1", 0);
149 STOPEVENT(p, S_EXIT, rv);
150 wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */
153 * Check if any loadable modules need anything done at process exit.
154 * e.g. SYSV IPC stuff
155 * XXX what if one of these generates an error?
157 TAILQ_FOREACH(ep, &exit_list, next)
158 (*ep->function)(p->p_thread);
160 if (p->p_flag & P_PROFIL)
162 MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage),
165 * If parent is waiting for us to exit or exec,
166 * P_PPWAIT is set; we will wakeup the parent below.
168 p->p_flag &= ~(P_TRACED | P_PPWAIT);
169 p->p_flag |= P_WEXIT;
170 SIGEMPTYSET(p->p_siglist);
171 if (timevalisset(&p->p_realtimer.it_value))
172 untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
175 * Reset any sigio structures pointing to us as a result of
176 * F_SETOWN with our pid.
178 funsetownlst(&p->p_sigiolst);
181 * Close open files and release open-file table.
186 if(p->p_leader->p_peers) {
188 while(q->p_peers != p)
190 q->p_peers = p->p_peers;
191 wakeup((caddr_t)p->p_leader);
195 * XXX Shutdown SYSV semaphores
199 /* The next two chunks should probably be moved to vmspace_exit. */
202 * Release user portion of address space.
203 * This releases references to vnodes,
204 * which could cause I/O if the file has been unlinked.
205 * Need to do this early enough that we can still sleep.
206 * Can't free the entire vmspace as the kernel stack
207 * may be mapped within that space also.
209 * Processes sharing the same vmspace may exit in one order, and
210 * get cleaned up by vmspace_exit() in a different order. The
211 * last exiting process to reach this point releases as much of
212 * the environment as it can, and the last process cleaned up
213 * by vmspace_exit() (which decrements exitingcnt) cleans up the
217 if (--vm->vm_refcnt == 0) {
219 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS,
221 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS,
225 if (SESS_LEADER(p)) {
226 struct session *sp = p->p_session;
230 * Controlling process.
231 * Signal foreground pgrp,
232 * drain controlling terminal
233 * and revoke access to controlling terminal.
235 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
236 if (sp->s_ttyp->t_pgrp)
237 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
238 (void) ttywait(sp->s_ttyp);
240 * The tty could have been revoked
244 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
250 * s_ttyp is not zero'd; we use this to indicate
251 * that the session once had a controlling terminal.
252 * (for logging and informational purposes)
257 fixjobc(p, p->p_pgrp, 0);
258 (void)acct_process(p);
263 p->p_traceflag = 0; /* don't trace the vrele() */
264 if ((vtmp = p->p_tracep) != NULL) {
270 * Release reference to text vnode
272 if ((vtmp = p->p_textvp) != NULL) {
278 * Once we set SZOMB the process can get reaped. The wait1 code
279 * will also wait for TDF_RUNNING to be cleared in the thread's flags,
280 * indicating that it has been completely switched out.
284 * Remove proc from allproc queue and pidhash chain.
285 * Place onto zombproc. Unlink from parent's child list.
287 LIST_REMOVE(p, p_list);
288 LIST_INSERT_HEAD(&zombproc, p, p_list);
291 LIST_REMOVE(p, p_hash);
293 q = LIST_FIRST(&p->p_children);
294 if (q) /* only need this if any child is S_ZOMB */
295 wakeup((caddr_t) initproc);
296 for (; q != 0; q = nq) {
297 nq = LIST_NEXT(q, p_sibling);
298 LIST_REMOVE(q, p_sibling);
299 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
300 q->p_pptr = initproc;
301 q->p_sigparent = SIGCHLD;
303 * Traced processes are killed
304 * since their existence means someone is screwing up.
306 if (q->p_flag & P_TRACED) {
307 q->p_flag &= ~P_TRACED;
313 * Save exit status and final rusage info, adding in child rusage
314 * info and self times.
317 *p->p_ru = p->p_stats->p_ru;
318 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
319 ruadd(p->p_ru, &p->p_stats->p_cru);
322 * notify interested parties of our demise.
324 KNOTE(&p->p_klist, NOTE_EXIT);
327 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
328 * flag set, notify process 1 instead (and hope it will handle
331 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) {
332 struct proc *pp = p->p_pptr;
333 proc_reparent(p, initproc);
335 * If this was the last child of our parent, notify
336 * parent, so in case he was wait(2)ing, he will
339 if (LIST_EMPTY(&pp->p_children))
343 if (p->p_sigparent && p->p_pptr != initproc) {
344 psignal(p->p_pptr, p->p_sigparent);
346 psignal(p->p_pptr, SIGCHLD);
349 wakeup((caddr_t)p->p_pptr);
351 /* move this to cpu_exit */
352 p->p_thread->td_pcb->pcb_saveacc.faddr = (float *)NULL;
355 * cpu_exit is responsible for clearing curproc, since
356 * it is heavily integrated with the thread/switching sequence.
358 * Other substructures are freed from wait().
360 if (--p->p_limit->p_refcnt == 0) {
361 FREE(p->p_limit, M_SUBPROC);
366 * Release the P_CURPROC designation on the process so the userland
367 * scheduler can work in someone else.
372 * Finally, call machine-dependent code to release the remaining
373 * resources including address space, the kernel stack and pcb.
374 * The address space is released by "vmspace_free(p->p_vmspace)";
375 * This is machine-dependent, as we may have to change stacks
376 * or ensure that the current one isn't reallocated before we
377 * finish. cpu_exit will end with a call to cpu_switch(), finishing
378 * our execution (pun intended).
384 wait4(struct wait_args *uap)
386 struct rusage rusage;
389 error = kern_wait(uap->pid, uap->status ? &status : NULL,
390 uap->options, uap->rusage ? &rusage : NULL, &uap->sysmsg_fds[0]);
392 if (error == 0 && uap->status)
393 error = copyout(&status, uap->status, sizeof(*uap->status));
394 if (error == 0 && uap->rusage)
395 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
402 * wait_args(int pid, int *status, int options, struct rusage *rusage)
405 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
407 struct thread *td = curthread;
408 struct proc *q = td->td_proc;
414 if (options &~ (WUNTRACED|WNOHANG|WLINUXCLONE))
418 LIST_FOREACH(p, &q->p_children, p_sibling) {
419 if (pid != WAIT_ANY &&
420 p->p_pid != pid && p->p_pgid != -pid)
423 /* This special case handles a kthread spawned by linux_clone
424 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions
425 * need to be able to distinguish between waiting on a process and
426 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD,
427 * and the WLINUXCLONE option signifies we want to wait for threads
430 if ((p->p_sigparent != SIGCHLD) ^ ((options & WLINUXCLONE) != 0))
434 if (p->p_stat == SZOMB) {
436 * The process's thread may still be in the middle
437 * of switching away, we can't rip its stack out from
438 * under it until TDF_RUNNING clears!
440 * YYY no wakeup occurs so we depend on the timeout.
442 if ((p->p_thread->td_flags & TDF_RUNNING) != 0) {
443 tsleep(p->p_thread, 0, "reap", 1);
448 * Other kernel threads may be in the middle of
449 * accessing the proc. For example, kern/kern_proc.c
450 * could be blocked writing proc data to a sysctl.
451 * At the moment, if this occurs, we are not woken
452 * up and rely on a one-second retry.
456 tsleep(p, 0, "reap2", hz);
458 lwkt_wait_free(p->p_thread);
460 /* charge childs scheduling cpu usage to parent */
461 if (curproc->p_pid != 1) {
463 ESTCPULIM(curproc->p_estcpu + p->p_estcpu);
466 /* Take care of our return values. */
469 *status = p->p_xstat;
473 * If we got the child via a ptrace 'attach',
474 * we need to give it back to the old parent.
476 if (p->p_oppid && (t = pfind(p->p_oppid))) {
484 ruadd(&q->p_stats->p_cru, p->p_ru);
485 FREE(p->p_ru, M_ZOMBIE);
489 * Decrement the count of procs running with this uid.
491 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
494 * Free up credentials.
500 * Remove unused arguments
502 if (p->p_args && --p->p_args->ar_ref == 0)
503 FREE(p->p_args, M_PARGS);
506 * Finally finished with old proc entry.
507 * Unlink it from its process group and free it.
510 LIST_REMOVE(p, p_list); /* off zombproc */
511 LIST_REMOVE(p, p_sibling);
513 if (--p->p_procsig->ps_refcnt == 0) {
514 if (p->p_sigacts != &p->p_addr->u_sigacts)
515 FREE(p->p_sigacts, M_SUBPROC);
516 FREE(p->p_procsig, M_SUBPROC);
525 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 &&
526 (p->p_flag & P_TRACED || options & WUNTRACED)) {
527 p->p_flag |= P_WAITED;
531 *status = W_STOPCODE(p->p_xstat);
532 /* Zero rusage so we get something consistent. */
534 bzero(rusage, sizeof(rusage));
540 if (options & WNOHANG) {
544 error = tsleep((caddr_t)q, PCATCH, "wait", 0);
551 * make process 'parent' the new parent of process 'child'.
554 proc_reparent(child, parent)
559 if (child->p_pptr == parent)
562 LIST_REMOVE(child, p_sibling);
563 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
564 child->p_pptr = parent;
568 * The next two functions are to handle adding/deleting items on the
572 * Take the arguments given and put them onto the exit callout list,
573 * However first make sure that it's not already there.
574 * returns 0 on success.
579 exitlist_fn function;
584 /* Be noisy if the programmer has lost track of things */
585 if (rm_at_exit(function))
586 printf("WARNING: exit callout entry (%p) already present\n",
589 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
592 ep->function = function;
593 TAILQ_INSERT_TAIL(&exit_list, ep, next);
598 * Scan the exit callout list for the given item and remove it.
599 * Returns the number of items removed (0 or 1)
603 exitlist_fn function;
607 TAILQ_FOREACH(ep, &exit_list, next) {
608 if (ep->function == function) {
609 TAILQ_REMOVE(&exit_list, ep, next);
617 void check_sigacts (void)
619 struct proc *p = curproc;
623 if (p->p_procsig->ps_refcnt == 1 &&
624 p->p_sigacts != &p->p_addr->u_sigacts) {
627 p->p_addr->u_sigacts = *pss;
628 p->p_sigacts = &p->p_addr->u_sigacts;
630 FREE(pss, M_SUBPROC);