/* $OpenBSD: kern_exit.c,v 1.45 2003/06/21 00:42:58 tedu Exp $ */ /* $NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $ */ /* * 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. 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef SYSVSHM #include #endif #ifdef SYSVSEM #include #endif #include "systrace.h" #include #include #include #include #include /* * exit -- * Death of process. */ int sys_exit(p, v, retval) struct proc *p; void *v; register_t *retval; { struct sys_exit_args /* { syscallarg(int) rval; } */ *uap = v; exit1(p, W_EXITCODE(SCARG(uap, rval), 0)); /* NOTREACHED */ return (0); } /* * 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(p, rv) struct proc *p; int rv; { struct proc *q, *nq; if (p->p_pid == 1) panic("init died (signal %d, exit %d)", WTERMSIG(rv), WEXITSTATUS(rv)); if (p->p_flag & P_PROFIL) stopprofclock(p); p->p_ru = pool_get(&rusage_pool, PR_WAITOK); /* * If parent is waiting for us to exit or exec, P_PPWAIT is set; we * wake up the parent early to avoid deadlock. */ p->p_flag |= P_WEXIT; p->p_flag &= ~P_TRACED; if (p->p_flag & P_PPWAIT) { p->p_flag &= ~P_PPWAIT; wakeup((caddr_t)p->p_pptr); } p->p_sigignore = ~0; p->p_siglist = 0; timeout_del(&p->p_realit_to); /* * Close open files and release open-file table. * This may block! */ fdfree(p); #ifdef SYSVSEM semexit(p); #endif if (SESS_LEADER(p)) { register struct session *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->t_session == sp) { if (sp->s_ttyp->t_pgrp) pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1); (void) ttywait(sp->s_ttyp); /* * The tty could have been revoked * if we blocked. */ if (sp->s_ttyvp) VOP_REVOKE(sp->s_ttyvp, REVOKEALL); } if (sp->s_ttyvp) vrele(sp->s_ttyvp); sp->s_ttyvp = NULL; /* * s_ttyp is not zero'd; we use this to indicate * that the session once had a controlling terminal. * (for logging and informational purposes) */ } sp->s_leader = NULL; } fixjobc(p, p->p_pgrp, 0); (void)acct_process(p); #ifdef KTRACE /* * release trace file */ p->p_traceflag = 0; /* don't trace the vrele() */ if (p->p_tracep) ktrsettracevnode(p, NULL); #endif #if NSYSTRACE > 0 if (ISSET(p->p_flag, P_SYSTRACE)) systrace_exit(p); #endif /* * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! */ p->p_stat = SDEAD; /* * Remove proc from pidhash chain so looking it up won't * work. Move it from allproc to zombproc, but do not yet * wake up the reaper. We will put the proc on the * deadproc list later (using the p_hash member), and * wake up the reaper when we do. */ LIST_REMOVE(p, p_hash); LIST_REMOVE(p, p_list); LIST_INSERT_HEAD(&zombproc, p, p_list); /* * Give orphaned children to init(8). */ q = p->p_children.lh_first; if (q) /* only need this if any child is S_ZOMB */ wakeup((caddr_t)initproc); for (; q != 0; q = nq) { nq = q->p_sibling.le_next; proc_reparent(q, initproc); /* * 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); } } /* * 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; calcru(p, &p->p_ru->ru_utime, &p->p_ru->ru_stime, NULL); ruadd(p->p_ru, &p->p_stats->p_cru); /* * clear %cpu usage during swap */ p->p_pctcpu = 0; /* * notify interested parties of our demise. */ KNOTE(&p->p_klist, NOTE_EXIT); /* * Notify parent that we're gone. If we have P_NOZOMBIE or parent has * the P_NOCLDWAIT flag set, notify process 1 instead (and hope it * will handle this situation). */ if ((p->p_flag & P_NOZOMBIE) || (p->p_pptr->p_flag & P_NOCLDWAIT)) { struct proc *pp = p->p_pptr; proc_reparent(p, initproc); /* * If this was the last child of our parent, notify * parent, so in case he was wait(2)ing, he will * continue. */ if (pp->p_children.lh_first == NULL) wakeup((caddr_t)pp); } if ((p->p_flag & P_FSTRACE) == 0 && p->p_exitsig != 0) psignal(p->p_pptr, P_EXITSIG(p)); wakeup((caddr_t)p->p_pptr); /* * Notify procfs debugger */ if (p->p_flag & P_FSTRACE) wakeup((caddr_t)p); /* * Release the process's signal state. */ sigactsfree(p); /* * 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(). */ curproc = NULL; limfree(p->p_limit); p->p_limit = NULL; /* * If emulation has process exit hook, call it now. */ if (p->p_emul->e_proc_exit) (*p->p_emul->e_proc_exit)(p); /* * Finally, call machine-dependent code to switch to a new * context (possibly the idle context). Once we are no longer * using the dead process's vmspace and stack, exit2() will be * called to schedule those resources to be released by the * reaper thread. * * Note that cpu_exit() will end with a call equivalent to * cpu_switch(), finishing our execution (pun intended). */ cpu_exit(p); } /* * We are called from cpu_exit() once it is safe to schedule the * dead process's resources to be freed. * * NOTE: One must be careful with locking in this routine. It's * called from a critical section in machine-dependent code, so * we should refrain from changing any interrupt state. * * We lock the deadproc list (a spin lock), place the proc on that * list (using the p_hash member), and wake up the reaper. */ void exit2(p) struct proc *p; { simple_lock(&deadproc_slock); LIST_INSERT_HEAD(&deadproc, p, p_hash); simple_unlock(&deadproc_slock); wakeup(&deadproc); } /* * Process reaper. This is run by a kernel thread to free the resources * of a dead process. Once the resources are free, the process becomes * a zombie, and the parent is allowed to read the undead's status. */ void reaper(void) { struct proc *p; for (;;) { simple_lock(&deadproc_slock); p = LIST_FIRST(&deadproc); if (p == NULL) { /* No work for us; go to sleep until someone exits. */ simple_unlock(&deadproc_slock); (void) tsleep(&deadproc, PVM, "reaper", 0); continue; } /* Remove us from the deadproc list. */ LIST_REMOVE(p, p_hash); simple_unlock(&deadproc_slock); /* * Give machine-dependent code a chance to free any * resources it couldn't free while still running on * that process's context. This must be done before * uvm_exit(), in case these resources are in the PCB. */ cpu_wait(p); /* * Free the VM resources we're still holding on to. * We must do this from a valid thread because doing * so may block. */ uvm_exit(p); /* Process is now a true zombie. */ if ((p->p_flag & P_NOZOMBIE) == 0) { p->p_stat = SZOMB; /* Wake up the parent so it can get exit status. */ psignal(p->p_pptr, SIGCHLD); wakeup((caddr_t)p->p_pptr); } else { /* Noone will wait for us. Just zap the process now */ proc_zap(p); } } } int sys_wait4(q, v, retval) register struct proc *q; void *v; register_t *retval; { register struct sys_wait4_args /* { syscallarg(int) pid; syscallarg(int *) status; syscallarg(int) options; syscallarg(struct rusage *) rusage; } */ *uap = v; register int nfound; register struct proc *p, *t; int status, error; if (SCARG(uap, pid) == 0) SCARG(uap, pid) = -q->p_pgid; if (SCARG(uap, options) &~ (WUNTRACED|WNOHANG|WALTSIG)) return (EINVAL); loop: nfound = 0; for (p = q->p_children.lh_first; p != 0; p = p->p_sibling.le_next) { if ((p->p_flag & P_NOZOMBIE) || (SCARG(uap, pid) != WAIT_ANY && p->p_pid != SCARG(uap, pid) && p->p_pgid != -SCARG(uap, pid))) continue; /* * Wait for processes with p_exitsig != SIGCHLD processes only * if WALTSIG is set; wait for processes with pexitsig == * SIGCHLD only if WALTSIG is clear. */ if ((SCARG(uap, options) & WALTSIG) ? (p->p_exitsig == SIGCHLD) : (P_EXITSIG(p) != SIGCHLD)) continue; nfound++; if (p->p_stat == SZOMB) { retval[0] = p->p_pid; if (SCARG(uap, status)) { status = p->p_xstat; /* convert to int */ error = copyout((caddr_t)&status, (caddr_t)SCARG(uap, status), sizeof(status)); if (error) return (error); } if (SCARG(uap, rusage) && (error = copyout((caddr_t)p->p_ru, (caddr_t)SCARG(uap, rusage), sizeof(struct rusage)))) return (error); /* * If we got the child via a ptrace 'attach', * we need to give it back to the old parent. */ if (p->p_oppid && (t = pfind(p->p_oppid))) { p->p_oppid = 0; proc_reparent(p, t); if (p->p_exitsig != 0) psignal(t, P_EXITSIG(p)); wakeup((caddr_t)t); return (0); } scheduler_wait_hook(q, p); p->p_xstat = 0; ruadd(&q->p_stats->p_cru, p->p_ru); proc_zap(p); return (0); } if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && (p->p_flag & P_TRACED || SCARG(uap, options) & WUNTRACED)) { p->p_flag |= P_WAITED; retval[0] = p->p_pid; if (SCARG(uap, status)) { status = W_STOPCODE(p->p_xstat); error = copyout((caddr_t)&status, (caddr_t)SCARG(uap, status), sizeof(status)); } else error = 0; return (error); } } if (nfound == 0) return (ECHILD); if (SCARG(uap, options) & WNOHANG) { retval[0] = 0; return (0); } if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 0)) != 0) return (error); goto loop; } /* * make process 'parent' the new parent of process 'child'. */ void proc_reparent(child, parent) register struct proc *child; register struct proc *parent; { if (child->p_pptr == parent) return; if (parent == initproc) child->p_exitsig = SIGCHLD; LIST_REMOVE(child, p_sibling); LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); child->p_pptr = parent; } void proc_zap(struct proc *p) { pool_put(&rusage_pool, p->p_ru); /* * Finally finished with old proc entry. * Unlink it from its process group and free it. */ leavepgrp(p); LIST_REMOVE(p, p_list); /* off zombproc */ LIST_REMOVE(p, p_sibling); /* * Decrement the count of procs running with this uid. */ (void)chgproccnt(p->p_cred->p_ruid, -1); /* * Free up credentials. */ if (--p->p_cred->p_refcnt == 0) { crfree(p->p_cred->pc_ucred); pool_put(&pcred_pool, p->p_cred); } /* * Release reference to text vnode */ if (p->p_textvp) vrele(p->p_textvp); pool_put(&proc_pool, p); nprocs--; }