diff options
Diffstat (limited to 'sys/kern/kern_exit.c')
| -rw-r--r-- | sys/kern/kern_exit.c | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c new file mode 100644 index 0000000..fab9437 --- /dev/null +++ b/sys/kern/kern_exit.c @@ -0,0 +1,805 @@ +/* + * 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/lock.h> +#include <sys/mutex.h> +#include <sys/proc.h> +#include <sys/pioctl.h> +#include <sys/tty.h> +#include <sys/wait.h> +#include <sys/vmmeter.h> +#include <sys/vnode.h> +#include <sys/resourcevar.h> +#include <sys/signalvar.h> +#include <sys/sx.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/jail.h> +#ifdef KTRACE +#include <sys/ktrace.h> +#endif + +#include <vm/vm.h> +#include <vm/vm_extern.h> +#include <vm/vm_param.h> +#include <vm/pmap.h> +#include <vm/vm_map.h> +#include <vm/uma.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(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 exitlist *ep; + struct proc *p, *nq, *q; + struct tty *tp; + struct vnode *ttyvp; + register struct vmspace *vm; + struct vnode *vtmp; +#ifdef KTRACE + struct vnode *tracevp; +#endif + + GIANT_REQUIRED; + + 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!"); + } + + /* + * XXXXKSE: MUST abort all other threads before proceeding past here. + */ + + /* 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. + */ + funsetownlst(&p->p_sigiolst); + + /* + * 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; + } + + sx_xlock(&proctree_lock); + 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. */ + 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_REVOKE(ttyvp, REVOKEALL); + vrele(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); +#ifdef KTRACE + /* + * release trace file + */ + PROC_LOCK(p); + mtx_lock(&ktrace_mtx); + p->p_traceflag = 0; /* don't trace the vrele() */ + tracevp = p->p_tracep; + p->p_tracep = NULL; + mtx_unlock(&ktrace_mtx); + PROC_UNLOCK(p); + if (tracevp != NULL) + vrele(tracevp); +#endif + /* + * Release reference to text vnode + */ + if ((vtmp = p->p_textvp) != NULL) { + p->p_textvp = NULL; + vrele(vtmp); + } + + /* + * Release our limits structure. + */ + 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); + + /* + * 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. + */ + PROC_LOCK(p); + 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); + + /* + * 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, 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); + if (p->p_pptr->p_procsig->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { + struct proc *pp; + + 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); + + /* + * 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); + PROC_LOCK(p->p_pptr); + sx_xunlock(&proctree_lock); + 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->p_pptr); + PROC_UNLOCK(p); + + cnt.v_swtch++; + binuptime(PCPU_PTR(switchtime)); + PCPU_SET(switchticks, ticks); + + cpu_sched_exit(td); + 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; +{ + struct rusage ru; + register int nfound; + register struct proc *p, *q, *t; + 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|WCONTINUED|WLINUXCLONE)) + return (EINVAL); + mtx_lock(&Giant); +loop: + nfound = 0; + sx_xlock(&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++; + 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) { + mtx_lock_spin(&sched_lock); + curthread->td_ksegrp->kg_estcpu = + ESTCPULIM(curthread->td_ksegrp->kg_estcpu + + p->p_ksegrp.kg_estcpu); + mtx_unlock_spin(&sched_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 */ + PROC_UNLOCK(p); + if ((error = copyout((caddr_t)&status, + (caddr_t)uap->status, sizeof(status)))) { + sx_xunlock(&proctree_lock); + mtx_unlock(&Giant); + return (error); + } + PROC_LOCK(p); + } + if (uap->rusage) { + bcopy(p->p_ru, &ru, sizeof(ru)); + PROC_UNLOCK(p); + if ((error = copyout((caddr_t)&ru, + (caddr_t)uap->rusage, + sizeof (struct rusage)))) { + sx_xunlock(&proctree_lock); + mtx_unlock(&Giant); + return (error); + } + } else + PROC_UNLOCK(p); + /* + * 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)) != 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); + mtx_unlock(&Giant); + return (0); + } + /* + * Remove other references to this process to ensure + * we have an exclusive reference. + */ + leavepgrp(p); + + sx_xlock(&allproc_lock); + LIST_REMOVE(p, p_list); /* off zombproc */ + sx_xunlock(&allproc_lock); + + LIST_REMOVE(p, p_sibling); + 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, p->p_ru); + 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 up credentials. + */ + crfree(p->p_ucred); + p->p_ucred = NULL; /* XXX: why? */ + + /* + * Remove unused arguments + */ + pargs_drop(p->p_args); + p->p_args = NULL; + + 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); + sx_xlock(&allproc_lock); + nprocs--; + sx_xunlock(&allproc_lock); + mtx_unlock(&Giant); + 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; + sx_xunlock(&proctree_lock); + td->td_retval[0] = p->p_pid; +#ifdef COMPAT_43 + if (compat) { + td->td_retval[1] = W_STOPCODE(p->p_xstat); + PROC_UNLOCK(p); + error = 0; + } else +#endif + if (uap->status) { + status = W_STOPCODE(p->p_xstat); + PROC_UNLOCK(p); + error = copyout((caddr_t)&status, + (caddr_t)uap->status, sizeof(status)); + } else { + PROC_UNLOCK(p); + error = 0; + } + mtx_unlock(&Giant); + return (error); + } + if (uap->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 (uap->status) { + status = SIGCONT; + error = copyout((caddr_t)&status, + (caddr_t)uap->status, sizeof(status)); + } else + error = 0; + + mtx_unlock(&Giant); + return (error); + } + PROC_UNLOCK(p); + } + if (nfound == 0) { + sx_xunlock(&proctree_lock); + mtx_unlock(&Giant); + return (ECHILD); + } + if (uap->options & WNOHANG) { + sx_xunlock(&proctree_lock); + td->td_retval[0] = 0; + mtx_unlock(&Giant); + return (0); + } + PROC_LOCK(q); + sx_xunlock(&proctree_lock); + error = msleep((caddr_t)q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); + PROC_UNLOCK(q); + if (error) { + mtx_unlock(&Giant); + 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(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); +} |
