/*- * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_compat.h" #include "opt_ktrace.h" #include "opt_mac.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for acct_process() function prototype */ #include #include #include #include #ifdef KTRACE #include #endif #include #include #include #include #include #include #include /* Required to be non-static for SysVR4 emulator */ MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); /* * exit -- * Death of process. * * MPSAFE */ void sys_exit(struct thread *td, struct sys_exit_args *uap) { exit1(td, W_EXITCODE(uap->rval, 0)); /* NOTREACHED */ } /* * Exit: deallocate address space and other resources, change proc state * to zombie, and unlink proc from allproc and parent's lists. Save exit * status and rusage for wait(). Check for child processes and orphan them. */ void exit1(struct thread *td, int rv) { struct bintime new_switchtime; struct proc *p, *nq, *q; struct tty *tp; struct vnode *ttyvp; struct vmspace *vm; struct vnode *vtmp; #ifdef KTRACE struct vnode *tracevp; struct ucred *tracecred; #endif struct plimit *plim; int refcnt; /* * Drop Giant if caller has it. Eventually we should warn about * being called with Giant held. */ while (mtx_owned(&Giant)) mtx_unlock(&Giant); p = td->td_proc; if (p == initproc) { printf("init died (signal %d, exit %d)\n", WTERMSIG(rv), WEXITSTATUS(rv)); panic("Going nowhere without my init!"); } /* * MUST abort all other threads before proceeding past here. */ PROC_LOCK(p); if (p->p_flag & P_HADTHREADS) { retry: /* * First check if some other thread got here before us.. * if so, act apropriatly, (exit or suspend); */ thread_suspend_check(0); /* * Kill off the other threads. This requires * some co-operation from other parts of the kernel * so it may not be instantaneous. With this state set * any thread entering the kernel from userspace will * thread_exit() in trap(). Any thread attempting to * sleep will return immediately with EINTR or EWOULDBLOCK * which will hopefully force them to back out to userland * freeing resources as they go. Any thread attempting * to return to userland will thread_exit() from userret(). * thread_exit() will unsuspend us when the last of the * other threads exits. * If there is already a thread singler after resumption, * calling thread_single will fail; in that case, we just * re-check all suspension request, the thread should * either be suspended there or exit. */ if (thread_single(SINGLE_EXIT)) goto retry; /* * All other activity in this process is now stopped. * Threading support has been turned off. */ } p->p_flag |= P_WEXIT; PROC_UNLOCK(p); /* Are we a task leader? */ if (p == p->p_leader) { mtx_lock(&ppeers_lock); q = p->p_peers; while (q != NULL) { PROC_LOCK(q); psignal(q, SIGKILL); PROC_UNLOCK(q); q = q->p_peers; } while (p->p_peers != NULL) msleep(p, &ppeers_lock, PWAIT, "exit1", 0); mtx_unlock(&ppeers_lock); } PROC_LOCK(p); _STOPEVENT(p, S_EXIT, rv); wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ PROC_UNLOCK(p); /* * Check if any loadable modules need anything done at process exit. * E.g. SYSV IPC stuff * XXX what if one of these generates an error? */ EVENTHANDLER_INVOKE(process_exit, p); MALLOC(p->p_ru, struct rusage *, sizeof(struct rusage), M_ZOMBIE, M_WAITOK); /* * If parent is waiting for us to exit or exec, * P_PPWAIT is set; we will wakeup the parent below. */ PROC_LOCK(p); stopprofclock(p); p->p_flag &= ~(P_TRACED | P_PPWAIT); SIGEMPTYSET(p->p_siglist); SIGEMPTYSET(td->td_siglist); /* * Stop the real interval timer. If the handler is currently * executing, prevent it from rearming itself and let it finish. */ if (timevalisset(&p->p_realtimer.it_value) && callout_stop(&p->p_itcallout) == 0) { timevalclear(&p->p_realtimer.it_interval); msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); KASSERT(!timevalisset(&p->p_realtimer.it_value), ("realtime timer is still armed")); } PROC_UNLOCK(p); /* * Reset any sigio structures pointing to us as a result of * F_SETOWN with our pid. */ mtx_lock(&Giant); /* XXX: not sure if needed */ funsetownlst(&p->p_sigiolst); /* * Close open files and release open-file table. * This may block! */ fdfree(td); mtx_unlock(&Giant); /* * If this thread tickled GEOM, we need to wait for the giggling to * stop before we return to userland */ if (td->td_pflags & TDP_GEOM) g_waitidle(); /* * Remove ourself from our leader's peer list and wake our leader. */ mtx_lock(&ppeers_lock); if (p->p_leader->p_peers) { q = p->p_leader; while (q->p_peers != p) q = q->p_peers; q->p_peers = p->p_peers; wakeup(p->p_leader); } mtx_unlock(&ppeers_lock); /* The next two chunks should probably be moved to vmspace_exit. */ vm = p->p_vmspace; /* * Release user portion of address space. * This releases references to vnodes, * which could cause I/O if the file has been unlinked. * Need to do this early enough that we can still sleep. * Can't free the entire vmspace as the kernel stack * may be mapped within that space also. * * Processes sharing the same vmspace may exit in one order, and * get cleaned up by vmspace_exit() in a different order. The * last exiting process to reach this point releases as much of * the environment as it can, and the last process cleaned up * by vmspace_exit() (which decrements exitingcnt) cleans up the * remainder. */ atomic_add_int(&vm->vm_exitingcnt, 1); do refcnt = vm->vm_refcnt; while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); if (refcnt == 1) { shmexit(vm); pmap_remove_pages(vmspace_pmap(vm), vm_map_min(&vm->vm_map), vm_map_max(&vm->vm_map)); (void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), vm_map_max(&vm->vm_map)); } mtx_lock(&Giant); sx_xlock(&proctree_lock); if (SESS_LEADER(p)) { struct session *sp; sp = p->p_session; if (sp->s_ttyvp) { /* * Controlling process. * Signal foreground pgrp, * drain controlling terminal * and revoke access to controlling terminal. */ if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) { tp = sp->s_ttyp; if (sp->s_ttyp->t_pgrp) { PGRP_LOCK(sp->s_ttyp->t_pgrp); pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); PGRP_UNLOCK(sp->s_ttyp->t_pgrp); } /* XXX tp should be locked. */ sx_xunlock(&proctree_lock); (void) ttywait(tp); sx_xlock(&proctree_lock); /* * The tty could have been revoked * if we blocked. */ if (sp->s_ttyvp) { ttyvp = sp->s_ttyvp; SESS_LOCK(p->p_session); sp->s_ttyvp = NULL; SESS_UNLOCK(p->p_session); sx_xunlock(&proctree_lock); VOP_LOCK(ttyvp, LK_EXCLUSIVE, td); VOP_REVOKE(ttyvp, REVOKEALL); vput(ttyvp); sx_xlock(&proctree_lock); } } if (sp->s_ttyvp) { ttyvp = sp->s_ttyvp; SESS_LOCK(p->p_session); sp->s_ttyvp = NULL; SESS_UNLOCK(p->p_session); vrele(ttyvp); } /* * s_ttyp is not zero'd; we use this to indicate * that the session once had a controlling terminal. * (for logging and informational purposes) */ } SESS_LOCK(p->p_session); sp->s_leader = NULL; SESS_UNLOCK(p->p_session); } fixjobc(p, p->p_pgrp, 0); sx_xunlock(&proctree_lock); (void)acct_process(td); mtx_unlock(&Giant); #ifdef KTRACE /* * release trace file */ PROC_LOCK(p); mtx_lock(&ktrace_mtx); p->p_traceflag = 0; /* don't trace the vrele() */ tracevp = p->p_tracevp; p->p_tracevp = NULL; tracecred = p->p_tracecred; p->p_tracecred = NULL; mtx_unlock(&ktrace_mtx); PROC_UNLOCK(p); if (tracevp != NULL) { mtx_lock(&Giant); vrele(tracevp); mtx_unlock(&Giant); } if (tracecred != NULL) crfree(tracecred); #endif /* * Release reference to text vnode */ if ((vtmp = p->p_textvp) != NULL) { p->p_textvp = NULL; mtx_lock(&Giant); vrele(vtmp); mtx_unlock(&Giant); } /* * Release our limits structure. */ PROC_LOCK(p); plim = p->p_limit; p->p_limit = NULL; PROC_UNLOCK(p); lim_free(plim); /* * Remove proc from allproc queue and pidhash chain. * Place onto zombproc. Unlink from parent's child list. */ sx_xlock(&allproc_lock); LIST_REMOVE(p, p_list); LIST_INSERT_HEAD(&zombproc, p, p_list); LIST_REMOVE(p, p_hash); sx_xunlock(&allproc_lock); sx_xlock(&proctree_lock); q = LIST_FIRST(&p->p_children); if (q != NULL) /* only need this if any child is S_ZOMB */ wakeup(initproc); for (; q != NULL; q = nq) { nq = LIST_NEXT(q, p_sibling); PROC_LOCK(q); proc_reparent(q, initproc); q->p_sigparent = SIGCHLD; /* * Traced processes are killed * since their existence means someone is screwing up. */ if (q->p_flag & P_TRACED) { q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); psignal(q, SIGKILL); } PROC_UNLOCK(q); } /* * Save exit status and finalize rusage info except for times, * adding in child rusage info. */ PROC_LOCK(p); p->p_xstat = rv; p->p_xthread = td; p->p_stats->p_ru.ru_nvcsw++; *p->p_ru = p->p_stats->p_ru; ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); /* * Notify interested parties of our demise. */ KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); /* * Just delete all entries in the p_klist. At this point we won't * report any more events, and there are nasty race conditions that * can beat us if we don't. */ knlist_clear(&p->p_klist, 1); /* * Notify parent that we're gone. If parent has the PS_NOCLDWAIT * flag set, or if the handler is set to SIG_IGN, notify process * 1 instead (and hope it will handle this situation). */ PROC_LOCK(p->p_pptr); mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { struct proc *pp; mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); pp = p->p_pptr; PROC_UNLOCK(pp); proc_reparent(p, initproc); p->p_sigparent = SIGCHLD; PROC_LOCK(p->p_pptr); /* * If this was the last child of our parent, notify * parent, so in case he was wait(2)ing, he will * continue. */ if (LIST_EMPTY(&pp->p_children)) wakeup(pp); } else mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); if (p->p_pptr == initproc) psignal(p->p_pptr, SIGCHLD); else if (p->p_sigparent != 0) psignal(p->p_pptr, p->p_sigparent); PROC_UNLOCK(p->p_pptr); /* * If this is a kthread, then wakeup anyone waiting for it to exit. */ if (p->p_flag & P_KTHREAD) wakeup(p); PROC_UNLOCK(p); /* * Finally, call machine-dependent code to release the remaining * resources including address space. * The address space is released by "vmspace_exitfree(p)" in * vm_waitproc(). */ cpu_exit(td); WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, "process (pid %d) exiting", p->p_pid); PROC_LOCK(p); PROC_LOCK(p->p_pptr); sx_xunlock(&proctree_lock); /* * We have to wait until after acquiring all locks before * changing p_state. We need to avoid all possible context * switches (including ones from blocking on a mutex) while * marked as a zombie. We also have to set the zombie state * before we release the parent process' proc lock to avoid * a lost wakeup. So, we first call wakeup, then we grab the * sched lock, update the state, and release the parent process' * proc lock. */ wakeup(p->p_pptr); mtx_lock_spin(&sched_lock); p->p_state = PRS_ZOMBIE; PROC_UNLOCK(p->p_pptr); /* Do the same timestamp bookkeeping that mi_switch() would do. */ binuptime(&new_switchtime); bintime_add(&p->p_rux.rux_runtime, &new_switchtime); bintime_sub(&p->p_rux.rux_runtime, PCPU_PTR(switchtime)); PCPU_SET(switchtime, new_switchtime); PCPU_SET(switchticks, ticks); cnt.v_swtch++; sched_exit(p->p_pptr, td); /* * Hopefully no one will try to deliver a signal to the process this * late in the game. */ knlist_destroy(&p->p_klist); /* * Make sure the scheduler takes this thread out of its tables etc. * This will also release this thread's reference to the ucred. * Other thread parts to release include pcb bits and such. */ thread_exit(); } #ifdef COMPAT_43 /* * The dirty work is handled by kern_wait(). * * MPSAFE. */ int owait(struct thread *td, struct owait_args *uap __unused) { int error, status; error = kern_wait(td, WAIT_ANY, &status, 0, NULL); if (error == 0) td->td_retval[1] = status; return (error); } #endif /* COMPAT_43 */ /* * The dirty work is handled by kern_wait(). * * MPSAFE. */ int wait4(struct thread *td, struct wait_args *uap) { struct rusage ru, *rup; int error, status; if (uap->rusage != NULL) rup = &ru; else rup = NULL; error = kern_wait(td, uap->pid, &status, uap->options, rup); if (uap->status != NULL && error == 0) error = copyout(&status, uap->status, sizeof(status)); if (uap->rusage != NULL && error == 0) error = copyout(&ru, uap->rusage, sizeof(struct rusage)); return (error); } int kern_wait(struct thread *td, pid_t pid, int *status, int options, struct rusage *rusage) { struct proc *p, *q, *t; int error, nfound; q = td->td_proc; if (pid == 0) { PROC_LOCK(q); pid = -q->p_pgid; PROC_UNLOCK(q); } if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) return (EINVAL); loop: if (q->p_flag & P_STATCHILD) { PROC_LOCK(q); q->p_flag &= ~P_STATCHILD; PROC_UNLOCK(q); } nfound = 0; sx_xlock(&proctree_lock); LIST_FOREACH(p, &q->p_children, p_sibling) { PROC_LOCK(p); if (pid != WAIT_ANY && p->p_pid != pid && p->p_pgid != -pid) { PROC_UNLOCK(p); continue; } if (p_canwait(td, p)) { PROC_UNLOCK(p); continue; } /* * This special case handles a kthread spawned by linux_clone * (see linux_misc.c). The linux_wait4 and linux_waitpid * functions need to be able to distinguish between waiting * on a process and waiting on a thread. It is a thread if * p_sigparent is not SIGCHLD, and the WLINUXCLONE option * signifies we want to wait for threads and not processes. */ if ((p->p_sigparent != SIGCHLD) ^ ((options & WLINUXCLONE) != 0)) { PROC_UNLOCK(p); continue; } nfound++; if (p->p_state == PRS_ZOMBIE) { /* * It is possible that the last thread of this * process is still running on another CPU * in thread_exit() after having dropped the process * lock via PROC_UNLOCK() but before it has completed * cpu_throw(). In that case, the other thread must * still hold sched_lock, so simply by acquiring * sched_lock once we will wait long enough for the * thread to exit in that case. */ mtx_lock_spin(&sched_lock); mtx_unlock_spin(&sched_lock); td->td_retval[0] = p->p_pid; if (status) *status = p->p_xstat; /* convert to int */ if (rusage) { *rusage = *p->p_ru; calcru(p, &rusage->ru_utime, &rusage->ru_stime); } /* * If we got the child via a ptrace 'attach', * we need to give it back to the old parent. */ PROC_UNLOCK(p); if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { PROC_LOCK(p); p->p_oppid = 0; proc_reparent(p, t); PROC_UNLOCK(p); psignal(t, SIGCHLD); wakeup(t); PROC_UNLOCK(t); sx_xunlock(&proctree_lock); return (0); } /* * Remove other references to this process to ensure * we have an exclusive reference. */ sx_xlock(&allproc_lock); LIST_REMOVE(p, p_list); /* off zombproc */ sx_xunlock(&allproc_lock); LIST_REMOVE(p, p_sibling); leavepgrp(p); sx_xunlock(&proctree_lock); /* * As a side effect of this lock, we know that * all other writes to this proc are visible now, so * no more locking is needed for p. */ PROC_LOCK(p); p->p_xstat = 0; /* XXX: why? */ PROC_UNLOCK(p); PROC_LOCK(q); ruadd(&q->p_stats->p_cru, &q->p_crux, p->p_ru, &p->p_rux); PROC_UNLOCK(q); FREE(p->p_ru, M_ZOMBIE); p->p_ru = NULL; /* * Decrement the count of procs running with this uid. */ (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); /* * Free credentials, arguments, and sigacts. */ crfree(p->p_ucred); p->p_ucred = NULL; pargs_drop(p->p_args); p->p_args = NULL; sigacts_free(p->p_sigacts); p->p_sigacts = NULL; /* * Do any thread-system specific cleanups. */ thread_wait(p); /* * Give vm and machine-dependent layer a chance * to free anything that cpu_exit couldn't * release while still running in process context. */ vm_waitproc(p); #ifdef MAC mac_destroy_proc(p); #endif KASSERT(FIRST_THREAD_IN_PROC(p), ("kern_wait: no residual thread!")); uma_zfree(proc_zone, p); sx_xlock(&allproc_lock); nprocs--; sx_xunlock(&allproc_lock); return (0); } mtx_lock_spin(&sched_lock); if ((p->p_flag & P_STOPPED_SIG) && (p->p_suspcount == p->p_numthreads) && (p->p_flag & P_WAITED) == 0 && (p->p_flag & P_TRACED || options & WUNTRACED)) { mtx_unlock_spin(&sched_lock); p->p_flag |= P_WAITED; sx_xunlock(&proctree_lock); td->td_retval[0] = p->p_pid; if (status) *status = W_STOPCODE(p->p_xstat); PROC_UNLOCK(p); return (0); } mtx_unlock_spin(&sched_lock); if (options & WCONTINUED && (p->p_flag & P_CONTINUED)) { sx_xunlock(&proctree_lock); td->td_retval[0] = p->p_pid; p->p_flag &= ~P_CONTINUED; PROC_UNLOCK(p); if (status) *status = SIGCONT; return (0); } PROC_UNLOCK(p); } if (nfound == 0) { sx_xunlock(&proctree_lock); return (ECHILD); } if (options & WNOHANG) { sx_xunlock(&proctree_lock); td->td_retval[0] = 0; return (0); } PROC_LOCK(q); sx_xunlock(&proctree_lock); if (q->p_flag & P_STATCHILD) { q->p_flag &= ~P_STATCHILD; error = 0; } else error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); PROC_UNLOCK(q); if (error) return (error); goto loop; } /* * Make process 'parent' the new parent of process 'child'. * Must be called with an exclusive hold of proctree lock. */ void proc_reparent(struct proc *child, struct proc *parent) { sx_assert(&proctree_lock, SX_XLOCKED); PROC_LOCK_ASSERT(child, MA_OWNED); if (child->p_pptr == parent) return; LIST_REMOVE(child, p_sibling); LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); child->p_pptr = parent; }