/* * 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 #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 #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 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. */ PROC_LOCK(p); if (p->p_flag & P_KSES) { /* * First check if some other thread got here before us.. * if so, act apropriatly, (exit or suspend); */ thread_suspend_check(0); /* * Here is a trick.. * We need to free up our KSE to process other threads * so that we can safely set the UNBOUND flag * (whether or not we have a mailbox) as we are NEVER * going to return to the user. * The flag will not be set yet if we are exiting * because of a signal, pagefault, or similar * (or even an exit(2) from the UTS). */ td->td_flags |= TDF_UNBOUND; /* * Kill off the other threads. This requires * Some co-operation from other parts of the kernel * so it may not be instant. * With this state set: * Any thread entering the kernel from userspace will * thread_exit() in trap(). Any thread attempting to * sleep will return immediatly * with EINTR or EWOULDBLOCK, which will hopefully force them * to back out to userland, freeing resources as they go, and * anything attempting to return to userland will thread_exit() * from userret(). thread_exit() will unsuspend us * when the last other thread exits. */ if (thread_single(SINGLE_EXIT)) { panic ("Exit: Single threading fouled up"); } /* * All other activity in this process is now stopped. * Remove excess KSEs and KSEGRPS. XXXKSE (when we have them) * ... * Turn off threading support. */ p->p_flag &= ~P_KSES; td->td_flags &= ~TDF_UNBOUND; thread_single_end(); /* Don't need this any more. */ } /* * With this state set: * Any thread entering the kernel from userspace will thread_exit() * in trap(). Any thread attempting to sleep will return immediatly * with EINTR or EWOULDBLOCK, which will hopefully force them * to back out to userland, freeing resources as they go, and * anything attempting to return to userland will thread_exit() * from userret(). thread_exit() will do a wakeup on p->p_numthreads * if it transitions to 1. */ p->p_flag |= P_WEXIT; PROC_UNLOCK(p); /* 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(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); signal_delete(p, NULL, 0); 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(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_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)); 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(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(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(p); /* * And now, kill off its signals... */ signal_delete(p, NULL, 0); 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_state. 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_state = PRS_ZOMBIE; wakeup(p->p_pptr); PROC_UNLOCK(p->p_pptr); cnt.v_swtch++; binuptime(PCPU_PTR(switchtime)); PCPU_SET(switchticks, ticks); cpu_sched_exit(td); /* XXXKSE check if this should be in thread_exit */ /* * Make sure this thread is discarded from the zombie. * This will also release this thread's reference to the ucred. */ thread_exit(); 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; struct kse *ke; struct ksegrp *kg; 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_state == PRS_ZOMBIE) { /* * 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 + FIRST_KSEGRP_IN_PROC(p)->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(&status, 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(&ru, 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(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; } /* * There should only be one KSE/KSEGRP but * do it right anyhow. */ FOREACH_KSEGRP_IN_PROC(p, kg) { FOREACH_KSE_IN_GROUP(kg, ke) { /* Free the KSE spare thread. */ if (ke->ke_tdspare != NULL) { thread_free(ke->ke_tdspare); ke->ke_tdspare = NULL; } } } thread_reap(); /* check for zombie threads */ /* * 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); KASSERT(FIRST_THREAD_IN_PROC(p), ("wait1: no residual thread!")); uma_zfree(proc_zone, p); sx_xlock(&allproc_lock); nprocs--; sx_xunlock(&allproc_lock); mtx_unlock(&Giant); return (0); } if (P_SHOULDSTOP(p) && ((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(&status, 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(&status, 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(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); }