/* * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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 * $FreeBSD: head/sys/kern/kern_exit.c 94302 2002-04-09 20:00:40Z jhb $ */ #include "opt_compat.h" #include "opt_ktrace.h" #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 #include #include #include #include #include #include #include /* Required to be non-static for SysVR4 emulator */ MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback"); static int wait1(struct thread *, struct wait_args *, int); /* * callout list for things to do at exit time */ struct exitlist { exitlist_fn function; TAILQ_ENTRY(exitlist) next; }; TAILQ_HEAD(exit_list_head, exitlist); static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list); /* * exit -- * Death of process. * * MPSAFE */ void sys_exit(td, uap) struct thread *td; struct sys_exit_args /* { int rval; } */ *uap; { mtx_lock(&Giant); 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(td, rv) register struct thread *td; int rv; { struct proc *p = td->td_proc; register struct proc *q, *nq; register struct vmspace *vm; struct vnode *vtmp; struct exitlist *ep; struct vnode *ttyvp; struct tty *tp; GIANT_REQUIRED; if (p->p_pid == 1) { printf("init died (signal %d, exit %d)\n", WTERMSIG(rv), WEXITSTATUS(rv)); panic("Going nowhere without my init!"); } /* XXXXKSE */ /* MUST abort all other threads before proceeding past this point */ /* are we a task leader? */ PROC_LOCK(p); if(p == p->p_leader) { q = p->p_peers; while (q != NULL) { PROC_LOCK(q); psignal(q, SIGKILL); PROC_UNLOCK(q); q = q->p_peers; } while (p->p_peers) msleep((caddr_t)p, &p->p_mtx, PWAIT, "exit1", 0); } PROC_UNLOCK(p); #ifdef PGINPROF vmsizmon(); #endif STOPEVENT(p, S_EXIT, rv); wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ /* * 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? */ TAILQ_FOREACH(ep, &exit_list, next) (*ep->function)(p); stopprofclock(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); p->p_flag &= ~(P_TRACED | P_PPWAIT); p->p_flag |= P_WEXIT; SIGEMPTYSET(p->p_siglist); PROC_UNLOCK(p); if (timevalisset(&p->p_realtimer.it_value)) callout_stop(&p->p_itcallout); /* * Reset any sigio structures pointing to us as a result of * F_SETOWN with our pid. */ PROC_LOCK(p); funsetownlst(&p->p_sigiolst); PROC_UNLOCK(p); /* * Close open files and release open-file table. * This may block! */ fdfree(td); /* XXXKSE *//* may not be the one in proc */ /* * Remove ourself from our leader's peer list and wake our leader. */ PROC_LOCK(p->p_leader); 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((caddr_t)p->p_leader); } PROC_UNLOCK(p->p_leader); /* 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. */ if (--vm->vm_refcnt == 0) { if (vm->vm_shm) shmexit(p); pmap_remove_pages(vmspace_pmap(vm), VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); (void) vm_map_remove(&vm->vm_map, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); vm->vm_freer = p; } PGRPSESS_XLOCK(); if (SESS_LEADER(p)) { register 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. */ PGRPSESS_XUNLOCK(); (void) ttywait(tp); PGRPSESS_XLOCK(); /* * 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); PGRPSESS_XUNLOCK(); VOP_REVOKE(ttyvp, REVOKEALL); PGRPSESS_XLOCK(); vrele(ttyvp); } } 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); PGRPSESS_XUNLOCK(); (void)acct_process(td); #ifdef KTRACE /* * release trace file */ p->p_traceflag = 0; /* don't trace the vrele() */ if ((vtmp = p->p_tracep) != NULL) { p->p_tracep = NULL; vrele(vtmp); } #endif /* * Release reference to text vnode */ if ((vtmp = p->p_textvp) != NULL) { p->p_textvp = NULL; vrele(vtmp); } /* * 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((caddr_t) 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; psignal(q, SIGKILL); } PROC_UNLOCK(q); } /* * Save exit status and final rusage info, adding in child rusage * info and self times. */ p->p_xstat = rv; *p->p_ru = p->p_stats->p_ru; mtx_lock_spin(&sched_lock); calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); mtx_unlock_spin(&sched_lock); ruadd(p->p_ru, &p->p_stats->p_cru); /* * Pretend that an mi_switch() to the next process occurs now. We * must set `switchtime' directly since we will call cpu_switch() * directly. Set it now so that the rest of the exit time gets * counted somewhere if possible. */ mtx_lock_spin(&sched_lock); binuptime(PCPU_PTR(switchtime)); PCPU_SET(switchticks, ticks); mtx_unlock_spin(&sched_lock); /* * notify interested parties of our demise. */ PROC_LOCK(p); PROC_LOCK(p->p_pptr); KNOTE(&p->p_klist, NOTE_EXIT); /* * Notify parent that we're gone. If parent has the PS_NOCLDWAIT * flag set, notify process 1 instead (and hope it will handle * this situation). */ if (p->p_pptr->p_procsig->ps_flag & PS_NOCLDWAIT) { struct proc *pp = p->p_pptr; PROC_UNLOCK(pp); proc_reparent(p, initproc); 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((caddr_t)pp); } if (p->p_sigparent && p->p_pptr != initproc) psignal(p->p_pptr, p->p_sigparent); else psignal(p->p_pptr, SIGCHLD); 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((caddr_t)p); PROC_UNLOCK(p); sx_xunlock(&proctree_lock); /* * Clear curproc after we've done all operations * that could block, and before tearing down the rest * of the process state that might be used from clock, etc. * Also, can't clear curproc while we're still runnable, * as we're not on a run queue (we are current, just not * a proper proc any longer!). * * Other substructures are freed from wait(). */ mtx_assert(&Giant, MA_OWNED); if (--p->p_limit->p_refcnt == 0) { FREE(p->p_limit, M_SUBPROC); p->p_limit = NULL; } /* * Release this thread's reference to the ucred. The actual proc * reference will stay around until the proc is harvested by * wait(). At this point the ucred is immutable (no other threads * from this proc are around that can change it) so we leave the * per-thread ucred pointer intact in case it is needed although * in theory nothing should be using it at this point. */ crfree(td->td_ucred); /* * Finally, call machine-dependent code to release the remaining * resources including address space, the kernel stack and pcb. * The address space is released by "vmspace_exitfree(p)" in * vm_waitproc(). */ cpu_exit(td); PROC_LOCK(p); mtx_lock_spin(&sched_lock); while (mtx_owned(&Giant)) mtx_unlock(&Giant); /* * We have to wait until after releasing all locks before * changing p_stat. If we block on a mutex then we will be * back at SRUN when we resume and our parent will never * harvest us. */ p->p_stat = SZOMB; wakeup(p->p_pptr); PROC_UNLOCK(p); cnt.v_swtch++; cpu_throw(); panic("exit1"); } #ifdef COMPAT_43 /* * MPSAFE, the dirty work is handled by wait1(). */ int owait(td, uap) struct thread *td; register struct owait_args /* { int dummy; } */ *uap; { struct wait_args w; w.options = 0; w.rusage = NULL; w.pid = WAIT_ANY; w.status = NULL; return (wait1(td, &w, 1)); } #endif /* COMPAT_43 */ /* * MPSAFE, the dirty work is handled by wait1(). */ int wait4(td, uap) struct thread *td; struct wait_args *uap; { return (wait1(td, uap, 0)); } /* * MPSAFE */ static int wait1(td, uap, compat) register struct thread *td; register struct wait_args /* { int pid; int *status; int options; struct rusage *rusage; } */ *uap; int compat; { register int nfound; register struct proc *q, *p, *t; struct pargs *pa; int status, error; q = td->td_proc; if (uap->pid == 0) { PROC_LOCK(q); uap->pid = -q->p_pgid; PROC_UNLOCK(q); } if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) return (EINVAL); mtx_lock(&Giant); loop: nfound = 0; sx_slock(&proctree_lock); LIST_FOREACH(p, &q->p_children, p_sibling) { PROC_LOCK(p); if (uap->pid != WAIT_ANY && p->p_pid != uap->pid && p->p_pgid != -uap->pid) { 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) ^ ((uap->options & WLINUXCLONE) != 0)) { PROC_UNLOCK(p); continue; } nfound++; mtx_lock_spin(&sched_lock); if (p->p_stat == SZOMB) { /* * charge childs scheduling cpu usage to parent * XXXKSE assume only one thread & kse & ksegrp * keep estcpu in each ksegrp * so charge it to the ksegrp that did the wait * since process estcpu is sum of all ksegrps, * this is strictly as expected. * Assume that the child process aggregated all * tke estcpu into the 'build-in' ksegrp. * XXXKSE */ if (curthread->td_proc->p_pid != 1) { curthread->td_ksegrp->kg_estcpu = ESTCPULIM(curthread->td_ksegrp->kg_estcpu + p->p_ksegrp.kg_estcpu); } mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); sx_sunlock(&proctree_lock); td->td_retval[0] = p->p_pid; #ifdef COMPAT_43 if (compat) td->td_retval[1] = p->p_xstat; else #endif if (uap->status) { status = p->p_xstat; /* convert to int */ if ((error = copyout((caddr_t)&status, (caddr_t)uap->status, sizeof(status)))) { goto done2; } } if (uap->rusage && (error = copyout((caddr_t)p->p_ru, (caddr_t)uap->rusage, sizeof (struct rusage)))) { goto done2; } /* * If we got the child via a ptrace 'attach', * we need to give it back to the old parent. */ sx_xlock(&proctree_lock); if (p->p_oppid) { if ((t = pfind(p->p_oppid)) != NULL) { PROC_LOCK(p); p->p_oppid = 0; proc_reparent(p, t); PROC_UNLOCK(p); psignal(t, SIGCHLD); wakeup((caddr_t)t); PROC_UNLOCK(t); sx_xunlock(&proctree_lock); error = 0; goto done2; } } sx_xunlock(&proctree_lock); PROC_LOCK(p); p->p_xstat = 0; pa = p->p_args; p->p_args = NULL; PROC_UNLOCK(p); ruadd(&q->p_stats->p_cru, p->p_ru); 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); /* * Finally finished with old proc entry. * Unlink it from its process group and free it. */ leavepgrp(p); sx_xlock(&allproc_lock); LIST_REMOVE(p, p_list); /* off zombproc */ sx_xunlock(&allproc_lock); sx_xlock(&proctree_lock); LIST_REMOVE(p, p_sibling); sx_xunlock(&proctree_lock); /* * Free up credentials. */ crfree(p->p_ucred); p->p_ucred = NULL; /* * Remove unused arguments */ pargs_drop(pa); if (--p->p_procsig->ps_refcnt == 0) { if (p->p_sigacts != &p->p_uarea->u_sigacts) FREE(p->p_sigacts, M_SUBPROC); FREE(p->p_procsig, M_SUBPROC); p->p_procsig = NULL; } /* * 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); mtx_destroy(&p->p_mtx); uma_zfree(proc_zone, p); nprocs--; error = 0; goto done2; } if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && (p->p_flag & P_TRACED || uap->options & WUNTRACED)) { mtx_unlock_spin(&sched_lock); p->p_flag |= P_WAITED; PROC_UNLOCK(p); sx_sunlock(&proctree_lock); td->td_retval[0] = p->p_pid; #ifdef COMPAT_43 if (compat) { td->td_retval[1] = W_STOPCODE(p->p_xstat); error = 0; } else #endif if (uap->status) { status = W_STOPCODE(p->p_xstat); error = copyout((caddr_t)&status, (caddr_t)uap->status, sizeof(status)); } else error = 0; goto done2; } mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); } sx_sunlock(&proctree_lock); if (nfound == 0) { error = ECHILD; goto done2; } if (uap->options & WNOHANG) { td->td_retval[0] = 0; error = 0; goto done2; } if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) goto done2; goto loop; done2: mtx_unlock(&Giant); return(error); } /* * Make process 'parent' the new parent of process 'child'. * Must be called with an exclusive hold of proctree lock. */ void proc_reparent(child, parent) register struct proc *child; register 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; } /* * The next two functions are to handle adding/deleting items on the * exit callout list * * at_exit(): * Take the arguments given and put them onto the exit callout list, * However first make sure that it's not already there. * returns 0 on success. */ int at_exit(function) exitlist_fn function; { struct exitlist *ep; #ifdef INVARIANTS /* Be noisy if the programmer has lost track of things */ if (rm_at_exit(function)) printf("WARNING: exit callout entry (%p) already present\n", function); #endif ep = malloc(sizeof(*ep), M_ATEXIT, M_NOWAIT); if (ep == NULL) return (ENOMEM); ep->function = function; TAILQ_INSERT_TAIL(&exit_list, ep, next); return (0); } /* * Scan the exit callout list for the given item and remove it. * Returns the number of items removed (0 or 1) */ int rm_at_exit(function) exitlist_fn function; { struct exitlist *ep; TAILQ_FOREACH(ep, &exit_list, next) { if (ep->function == function) { TAILQ_REMOVE(&exit_list, ep, next); free(ep, M_ATEXIT); return(1); } } return (0); }