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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 1.33 2004/03/30 19:14:11 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 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 /* The next two chunks should probably be moved to vmspace_exit. */
207 * Release upcalls associated with this process
213 * Release user portion of address space.
214 * This releases references to vnodes,
215 * which could cause I/O if the file has been unlinked.
216 * Need to do this early enough that we can still sleep.
217 * Can't free the entire vmspace as the kernel stack
218 * may be mapped within that space also.
220 * Processes sharing the same vmspace may exit in one order, and
221 * get cleaned up by vmspace_exit() in a different order. The
222 * last exiting process to reach this point releases as much of
223 * the environment as it can, and the last process cleaned up
224 * by vmspace_exit() (which decrements exitingcnt) cleans up the
228 if (--vm->vm_refcnt == 0) {
230 pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS,
232 (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS,
236 if (SESS_LEADER(p)) {
237 struct session *sp = p->p_session;
241 * Controlling process.
242 * Signal foreground pgrp,
243 * drain controlling terminal
244 * and revoke access to controlling terminal.
246 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
247 if (sp->s_ttyp->t_pgrp)
248 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
249 (void) ttywait(sp->s_ttyp);
251 * The tty could have been revoked
255 VOP_REVOKE(sp->s_ttyvp, REVOKEALL);
261 * s_ttyp is not zero'd; we use this to indicate
262 * that the session once had a controlling terminal.
263 * (for logging and informational purposes)
268 fixjobc(p, p->p_pgrp, 0);
269 (void)acct_process(p);
274 p->p_traceflag = 0; /* don't trace the vrele() */
275 if ((vtmp = p->p_tracep) != NULL) {
281 * Release reference to text vnode
283 if ((vtmp = p->p_textvp) != NULL) {
289 * Once we set SZOMB the process can get reaped. The wait1 code
290 * will also wait for TDF_RUNNING to be cleared in the thread's flags,
291 * indicating that it has been completely switched out.
295 * Remove proc from allproc queue and pidhash chain.
296 * Place onto zombproc. Unlink from parent's child list.
298 LIST_REMOVE(p, p_list);
299 LIST_INSERT_HEAD(&zombproc, p, p_list);
302 LIST_REMOVE(p, p_hash);
304 q = LIST_FIRST(&p->p_children);
305 if (q) /* only need this if any child is S_ZOMB */
306 wakeup((caddr_t) initproc);
307 for (; q != 0; q = nq) {
308 nq = LIST_NEXT(q, p_sibling);
309 LIST_REMOVE(q, p_sibling);
310 LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling);
311 q->p_pptr = initproc;
312 q->p_sigparent = SIGCHLD;
314 * Traced processes are killed
315 * since their existence means someone is screwing up.
317 if (q->p_flag & P_TRACED) {
318 q->p_flag &= ~P_TRACED;
324 * Save exit status and final rusage info, adding in child rusage
325 * info and self times.
328 *p->p_ru = p->p_stats->p_ru;
329 calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL);
330 ruadd(p->p_ru, &p->p_stats->p_cru);
333 * notify interested parties of our demise.
335 KNOTE(&p->p_klist, NOTE_EXIT);
338 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
339 * flag set, notify process 1 instead (and hope it will handle
342 if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) {
343 struct proc *pp = p->p_pptr;
344 proc_reparent(p, initproc);
346 * If this was the last child of our parent, notify
347 * parent, so in case he was wait(2)ing, he will
350 if (LIST_EMPTY(&pp->p_children))
354 if (p->p_sigparent && p->p_pptr != initproc) {
355 psignal(p->p_pptr, p->p_sigparent);
357 psignal(p->p_pptr, SIGCHLD);
360 wakeup((caddr_t)p->p_pptr);
362 /* move this to cpu_exit */
363 p->p_thread->td_pcb->pcb_saveacc.faddr = (float *)NULL;
366 * cpu_exit is responsible for clearing curproc, since
367 * it is heavily integrated with the thread/switching sequence.
369 * Other substructures are freed from wait().
371 if (--p->p_limit->p_refcnt == 0) {
372 FREE(p->p_limit, M_SUBPROC);
377 * Release the current user process designation on the process so
378 * the userland scheduler can work in someone else.
383 * Finally, call machine-dependent code to release the remaining
384 * resources including address space, the kernel stack and pcb.
385 * The address space is released by "vmspace_free(p->p_vmspace)";
386 * This is machine-dependent, as we may have to change stacks
387 * or ensure that the current one isn't reallocated before we
388 * finish. cpu_exit will end with a call to cpu_switch(), finishing
389 * our execution (pun intended).
395 wait4(struct wait_args *uap)
397 struct rusage rusage;
400 error = kern_wait(uap->pid, uap->status ? &status : NULL,
401 uap->options, uap->rusage ? &rusage : NULL, &uap->sysmsg_fds[0]);
403 if (error == 0 && uap->status)
404 error = copyout(&status, uap->status, sizeof(*uap->status));
405 if (error == 0 && uap->rusage)
406 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
413 * wait_args(int pid, int *status, int options, struct rusage *rusage)
416 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
418 struct thread *td = curthread;
419 struct proc *q = td->td_proc;
425 if (options &~ (WUNTRACED|WNOHANG|WLINUXCLONE))
429 LIST_FOREACH(p, &q->p_children, p_sibling) {
430 if (pid != WAIT_ANY &&
431 p->p_pid != pid && p->p_pgid != -pid)
434 /* This special case handles a kthread spawned by linux_clone
435 * (see linux_misc.c). The linux_wait4 and linux_waitpid functions
436 * need to be able to distinguish between waiting on a process and
437 * waiting on a thread. It is a thread if p_sigparent is not SIGCHLD,
438 * and the WLINUXCLONE option signifies we want to wait for threads
441 if ((p->p_sigparent != SIGCHLD) ^ ((options & WLINUXCLONE) != 0))
445 if (p->p_stat == SZOMB) {
447 * The process's thread may still be in the middle
448 * of switching away, we can't rip its stack out from
449 * under it until TDF_RUNNING clears!
451 * YYY no wakeup occurs so we depend on the timeout.
453 if ((p->p_thread->td_flags & TDF_RUNNING) != 0) {
454 tsleep(p->p_thread, 0, "reap", 1);
459 * Other kernel threads may be in the middle of
460 * accessing the proc. For example, kern/kern_proc.c
461 * could be blocked writing proc data to a sysctl.
462 * At the moment, if this occurs, we are not woken
463 * up and rely on a one-second retry.
467 tsleep(p, 0, "reap2", hz);
469 lwkt_wait_free(p->p_thread);
472 * Charge the parent for the child's change in
473 * estimated cpu as of when the child exits to
474 * account for batch scripts, large make's, etc.
477 if (p->p_estcpu > p->p_estcpu_fork) {
478 q->p_estcpu = ESTCPULIM(q->p_estcpu +
479 p->p_estcpu - p->p_estcpu_fork);
483 /* Take care of our return values. */
486 *status = p->p_xstat;
490 * If we got the child via a ptrace 'attach',
491 * we need to give it back to the old parent.
493 if (p->p_oppid && (t = pfind(p->p_oppid))) {
501 ruadd(&q->p_stats->p_cru, p->p_ru);
502 FREE(p->p_ru, M_ZOMBIE);
506 * Decrement the count of procs running with this uid.
508 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
511 * Free up credentials.
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);
542 if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 &&
543 (p->p_flag & P_TRACED || options & WUNTRACED)) {
544 p->p_flag |= P_WAITED;
548 *status = W_STOPCODE(p->p_xstat);
549 /* Zero rusage so we get something consistent. */
551 bzero(rusage, sizeof(rusage));
557 if (options & WNOHANG) {
561 error = tsleep((caddr_t)q, PCATCH, "wait", 0);
568 * make process 'parent' the new parent of process 'child'.
571 proc_reparent(child, parent)
576 if (child->p_pptr == parent)
579 LIST_REMOVE(child, p_sibling);
580 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
581 child->p_pptr = parent;
585 * The next two functions are to handle adding/deleting items on the
589 * Take the arguments given and put them onto the exit callout list,
590 * However first make sure that it's not already there.
591 * returns 0 on success.
596 exitlist_fn function;
601 /* Be noisy if the programmer has lost track of things */
602 if (rm_at_exit(function))
603 printf("WARNING: exit callout entry (%p) already present\n",
606 ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
609 ep->function = function;
610 TAILQ_INSERT_TAIL(&exit_list, ep, next);
615 * Scan the exit callout list for the given item and remove it.
616 * Returns the number of items removed (0 or 1)
620 exitlist_fn function;
624 TAILQ_FOREACH(ep, &exit_list, next) {
625 if (ep->function == function) {
626 TAILQ_REMOVE(&exit_list, ep, next);
634 void check_sigacts (void)
636 struct proc *p = curproc;
640 if (p->p_procsig->ps_refcnt == 1 &&
641 p->p_sigacts != &p->p_addr->u_sigacts) {
644 p->p_addr->u_sigacts = *pss;
645 p->p_sigacts = &p->p_addr->u_sigacts;
647 FREE(pss, M_SUBPROC);