diff options
Diffstat (limited to 'sys/kern/kern_exit.c')
| -rw-r--r-- | sys/kern/kern_exit.c | 645 |
1 files changed, 645 insertions, 0 deletions
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c new file mode 100644 index 0000000..22e25b1 --- /dev/null +++ b/sys/kern/kern_exit.c @@ -0,0 +1,645 @@ +/* + * 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 + * $FreeBSD$ + */ + +#include "opt_compat.h" +#include "opt_ktrace.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/sysproto.h> +#include <sys/kernel.h> +#include <sys/malloc.h> +#include <sys/proc.h> +#include <sys/pioctl.h> +#include <sys/tty.h> +#include <sys/wait.h> +#include <sys/vnode.h> +#include <sys/resourcevar.h> +#include <sys/signalvar.h> +#include <sys/ptrace.h> +#include <sys/acct.h> /* for acct_process() function prototype */ +#include <sys/filedesc.h> +#include <sys/shm.h> +#include <sys/sem.h> +#include <sys/aio.h> +#include <sys/jail.h> + +#include <vm/vm.h> +#include <vm/vm_param.h> +#include <sys/lock.h> +#include <vm/pmap.h> +#include <vm/vm_map.h> +#include <vm/vm_zone.h> +#include <sys/user.h> + +/* 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 __P((struct proc *, 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. + */ +void +exit(p, uap) + struct proc *p; + struct rexit_args /* { + int rval; + } */ *uap; +{ + + exit1(p, 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(p, rv) + register struct proc *p; + int rv; +{ + register struct proc *q, *nq; + register struct vmspace *vm; + struct exitlist *ep; + + if (p->p_pid == 1) { + printf("init died (signal %d, exit %d)\n", + WTERMSIG(rv), WEXITSTATUS(rv)); + panic("Going nowhere without my init!"); + } + + aio_proc_rundown(p); + + /* are we a task leader? */ + if(p == p->p_leader) { + struct kill_args killArgs; + killArgs.signum = SIGKILL; + q = p->p_peers; + while(q) { + killArgs.pid = q->p_pid; + /* + * The interface for kill is better + * than the internal signal + */ + kill(p, &killArgs); + nq = q; + q = q->p_peers; + } + while (p->p_peers) + tsleep((caddr_t)p, PWAIT, "exit1", 0); + } + +#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); + + if (p->p_flag & P_PROFIL) + 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. + */ + p->p_flag &= ~(P_TRACED | P_PPWAIT); + p->p_flag |= P_WEXIT; + SIGEMPTYSET(p->p_siglist); + if (timevalisset(&p->p_realtimer.it_value)) + untimeout(realitexpire, (caddr_t)p, p->p_ithandle); + + /* + * Reset any sigio structures pointing to us as a result of + * F_SETOWN with our pid. + */ + funsetownlst(&p->p_sigiolst); + + /* + * Close open files and release open-file table. + * This may block! + */ + fdfree(p); + + 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); + } + + /* + * XXX Shutdown SYSV semaphores + */ + semexit(p); + + /* 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 == 1) { + 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); + } + + 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 && (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) + vrele(p->p_tracep); +#endif + /* + * Remove proc from allproc queue and pidhash chain. + * Place onto zombproc. Unlink from parent's child list. + */ + LIST_REMOVE(p, p_list); + LIST_INSERT_HEAD(&zombproc, p, p_list); + p->p_stat = SZOMB; + + LIST_REMOVE(p, p_hash); + + q = LIST_FIRST(&p->p_children); + if (q) /* only need this if any child is S_ZOMB */ + wakeup((caddr_t) initproc); + for (; q != 0; q = nq) { + nq = LIST_NEXT(q, p_sibling); + LIST_REMOVE(q, p_sibling); + LIST_INSERT_HEAD(&initproc->p_children, q, p_sibling); + q->p_pptr = 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); + } + } + + /* + * 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); + + /* + * 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. + */ + microuptime(&switchtime); + switchticks = ticks; + + /* + * notify interested parties of our demise. + */ + 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_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 (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); + } + + wakeup((caddr_t)p->p_pptr); +#if defined(tahoe) + /* move this to cpu_exit */ + p->p_addr->u_pcb.pcb_savacc.faddr = (float *)NULL; +#endif + /* + * 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(). + */ + SET_CURPROC(NULL); + if (--p->p_limit->p_refcnt == 0) { + FREE(p->p_limit, M_SUBPROC); + p->p_limit = NULL; + } + + /* + * 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_free(p->p_vmspace)"; + * This is machine-dependent, as we may have to change stacks + * or ensure that the current one isn't reallocated before we + * finish. cpu_exit will end with a call to cpu_switch(), finishing + * our execution (pun intended). + */ + cpu_exit(p); +} + +#ifdef COMPAT_43 +int +owait(p, uap) + struct proc *p; + 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(p, &w, 1)); +} +#endif /* COMPAT_43 */ + +int +wait4(p, uap) + struct proc *p; + struct wait_args *uap; +{ + + return (wait1(p, uap, 0)); +} + +static int +wait1(q, uap, compat) + register struct proc *q; + register struct wait_args /* { + int pid; + int *status; + int options; + struct rusage *rusage; + } */ *uap; + int compat; +{ + register int nfound; + register struct proc *p, *t; + int status, error; + + if (uap->pid == 0) + uap->pid = -q->p_pgid; + if (uap->options &~ (WUNTRACED|WNOHANG|WLINUXCLONE)) + return (EINVAL); +loop: + nfound = 0; + LIST_FOREACH(p, &q->p_children, p_sibling) { + if (uap->pid != WAIT_ANY && + p->p_pid != uap->pid && p->p_pgid != -uap->pid) + 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)) + continue; + + nfound++; + if (p->p_stat == SZOMB) { + /* charge childs scheduling cpu usage to parent */ + if (curproc->p_pid != 1) { + curproc->p_estcpu = + ESTCPULIM(curproc->p_estcpu + p->p_estcpu); + } + + q->p_retval[0] = p->p_pid; +#ifdef COMPAT_43 + if (compat) + q->p_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)))) + return (error); + } + if (uap->rusage && (error = copyout((caddr_t)p->p_ru, + (caddr_t)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); + psignal(t, SIGCHLD); + wakeup((caddr_t)t); + return (0); + } + p->p_xstat = 0; + 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_cred->p_ruid, -1, 0); + + /* + * Release reference to text vnode + */ + if (p->p_textvp) + vrele(p->p_textvp); + + /* + * Free up credentials. + */ + if (--p->p_cred->p_refcnt == 0) { + crfree(p->p_ucred); + FREE(p->p_cred, M_SUBPROC); + p->p_cred = NULL; + } + + /* + * Destroy empty prisons + */ + if (p->p_prison && !--p->p_prison->pr_ref) { + if (p->p_prison->pr_linux != NULL) + FREE(p->p_prison->pr_linux, M_PRISON); + FREE(p->p_prison, M_PRISON); + } + + /* + * Remove unused arguments + */ + if (p->p_args && --p->p_args->ar_ref == 0) + FREE(p->p_args, M_PARGS); + + /* + * 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); + + if (--p->p_procsig->ps_refcnt == 0) { + if (p->p_sigacts != &p->p_addr->u_sigacts) + FREE(p->p_sigacts, M_SUBPROC); + FREE(p->p_procsig, M_SUBPROC); + p->p_procsig = NULL; + } + + /* + * Give machine-dependent layer a chance + * to free anything that cpu_exit couldn't + * release while still running in process context. + */ + cpu_wait(p); + zfree(proc_zone, p); + nprocs--; + return (0); + } + if (p->p_stat == SSTOP && (p->p_flag & P_WAITED) == 0 && + (p->p_flag & P_TRACED || uap->options & WUNTRACED)) { + p->p_flag |= P_WAITED; + q->p_retval[0] = p->p_pid; +#ifdef COMPAT_43 + if (compat) { + q->p_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; + return (error); + } + } + if (nfound == 0) + return (ECHILD); + if (uap->options & WNOHANG) { + q->p_retval[0] = 0; + return (0); + } + if ((error = tsleep((caddr_t)q, PWAIT | PCATCH, "wait", 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; + + 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); +} + +void check_sigacts (void) +{ + struct proc *p = curproc; + struct sigacts *pss; + int s; + + if (p->p_procsig->ps_refcnt == 1 && + p->p_sigacts != &p->p_addr->u_sigacts) { + pss = p->p_sigacts; + s = splhigh(); + p->p_addr->u_sigacts = *pss; + p->p_sigacts = &p->p_addr->u_sigacts; + splx(s); + FREE(pss, M_SUBPROC); + } +} + |
