diff options
Diffstat (limited to 'sys/kern/kern_exit.c')
| -rw-r--r-- | sys/kern/kern_exit.c | 931 |
1 files changed, 931 insertions, 0 deletions
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c new file mode 100644 index 0000000..3ff3409 --- /dev/null +++ b/sys/kern/kern_exit.c @@ -0,0 +1,931 @@ +/*- + * 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. + * 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 + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "opt_compat.h" +#include "opt_ktrace.h" +#include "opt_mac.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/sysproto.h> +#include <sys/eventhandler.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/sbuf.h> +#include <sys/signalvar.h> +#include <sys/sched.h> +#include <sys/sx.h> +#include <sys/syscallsubr.h> +#include <sys/syslog.h> +#include <sys/ptrace.h> +#include <sys/acct.h> /* for acct_process() function prototype */ +#include <sys/filedesc.h> +#include <sys/mac.h> +#include <sys/shm.h> +#include <sys/sem.h> +#ifdef KTRACE +#include <sys/ktrace.h> +#endif + +#include <security/audit/audit.h> + +#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/vm_page.h> +#include <vm/uma.h> + +/* Required to be non-static for SysVR4 emulator */ +MALLOC_DEFINE(M_ZOMBIE, "zombie", "zombie proc status"); + +/* Hook for NFS teardown procedure. */ +void (*nlminfo_release_p)(struct proc *p); + +/* + * exit -- + * Death of process. + * + * MPSAFE + */ +void +sys_exit(struct thread *td, struct sys_exit_args *uap) +{ + + 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(struct thread *td, int rv) +{ + struct bintime new_switchtime; + struct proc *p, *nq, *q; + struct tty *tp; + struct vnode *ttyvp; + struct vmspace *vm; + struct vnode *vtmp; +#ifdef KTRACE + struct vnode *tracevp; + struct ucred *tracecred; +#endif + struct plimit *plim; + int locked, refcnt; + + /* + * Drop Giant if caller has it. Eventually we should warn about + * being called with Giant held. + */ + while (mtx_owned(&Giant)) + mtx_unlock(&Giant); + + 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!"); + } + + /* + * MUST abort all other threads before proceeding past here. + */ + PROC_LOCK(p); + if (p->p_flag & P_HADTHREADS) { +retry: + /* + * First check if some other thread got here before us.. + * if so, act apropriatly, (exit or suspend); + */ + thread_suspend_check(0); + + /* + * Kill off the other threads. This requires + * some co-operation from other parts of the kernel + * so it may not be instantaneous. With this state set + * any thread entering the kernel from userspace will + * thread_exit() in trap(). Any thread attempting to + * sleep will return immediately with EINTR or EWOULDBLOCK + * which will hopefully force them to back out to userland + * freeing resources as they go. Any thread attempting + * to return to userland will thread_exit() from userret(). + * thread_exit() will unsuspend us when the last of the + * other threads exits. + * If there is already a thread singler after resumption, + * calling thread_single will fail; in that case, we just + * re-check all suspension request, the thread should + * either be suspended there or exit. + */ + if (thread_single(SINGLE_EXIT)) + goto retry; + + /* + * All other activity in this process is now stopped. + * Threading support has been turned off. + */ + } + + p->p_flag |= P_WEXIT; + + PROC_LOCK(p->p_pptr); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(p->p_pptr); + + PROC_UNLOCK(p); + +#ifdef AUDIT + /* + * The Sun BSM exit token contains two components: an exit status as + * passed to exit(), and a return value to indicate what sort of exit + * it was. The exit status is WEXITSTATUS(rv), but it's not clear + * what the return value is. + */ + AUDIT_ARG(exit, WEXITSTATUS(rv), 0); + AUDIT_SYSCALL_EXIT(0, td); +#endif + + /* Are we a task leader? */ + if (p == p->p_leader) { + mtx_lock(&ppeers_lock); + q = p->p_peers; + while (q != NULL) { + PROC_LOCK(q); + psignal(q, SIGKILL); + PROC_UNLOCK(q); + q = q->p_peers; + } + while (p->p_peers != NULL) + msleep(p, &ppeers_lock, PWAIT, "exit1", 0); + mtx_unlock(&ppeers_lock); + } + + PROC_LOCK(p); + _STOPEVENT(p, S_EXIT, rv); + wakeup(&p->p_stype); /* Wakeup anyone in procfs' PIOCWAIT */ + PROC_UNLOCK(p); + + /* + * 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? + */ + EVENTHANDLER_INVOKE(process_exit, 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); + stopprofclock(p); + p->p_flag &= ~(P_TRACED | P_PPWAIT); + + /* + * Stop the real interval timer. If the handler is currently + * executing, prevent it from rearming itself and let it finish. + */ + if (timevalisset(&p->p_realtimer.it_value) && + callout_stop(&p->p_itcallout) == 0) { + timevalclear(&p->p_realtimer.it_interval); + msleep(&p->p_itcallout, &p->p_mtx, PWAIT, "ritwait", 0); + KASSERT(!timevalisset(&p->p_realtimer.it_value), + ("realtime timer is still armed")); + } + sigqueue_flush(&p->p_sigqueue); + sigqueue_flush(&td->td_sigqueue); + PROC_UNLOCK(p); + + /* + * Reset any sigio structures pointing to us as a result of + * F_SETOWN with our pid. + */ + mtx_lock(&Giant); /* XXX: not sure if needed */ + funsetownlst(&p->p_sigiolst); + mtx_unlock(&Giant); + + /* + * If this process has an nlminfo data area (for lockd), release it + */ + if (nlminfo_release_p != NULL && p->p_nlminfo != NULL) + (*nlminfo_release_p)(p); + + /* + * Close open files and release open-file table. + * This may block! + */ + fdfree(td); + + /* + * If this thread tickled GEOM, we need to wait for the giggling to + * stop before we return to userland + */ + if (td->td_pflags & TDP_GEOM) + g_waitidle(); + + /* + * Remove ourself from our leader's peer list and wake our leader. + */ + mtx_lock(&ppeers_lock); + 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); + } + mtx_unlock(&ppeers_lock); + + /* 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. + * + * Processes sharing the same vmspace may exit in one order, and + * get cleaned up by vmspace_exit() in a different order. The + * last exiting process to reach this point releases as much of + * the environment as it can, and the last process cleaned up + * by vmspace_exit() (which decrements exitingcnt) cleans up the + * remainder. + */ + atomic_add_int(&vm->vm_exitingcnt, 1); + do + refcnt = vm->vm_refcnt; + while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); + if (refcnt == 1) { + shmexit(vm); + 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)); + } + + sx_xlock(&proctree_lock); + if (SESS_LEADER(p)) { + struct session *sp; + + sp = p->p_session; + if (sp->s_ttyvp) { + locked = VFS_LOCK_GIANT(sp->s_ttyvp->v_mount); + /* + * 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_LOCK(ttyvp, LK_EXCLUSIVE, td); + VOP_REVOKE(ttyvp, REVOKEALL); + vput(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) + */ + VFS_UNLOCK_GIANT(locked); + } + 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 + /* + * Drain any pending records on the thread and release the trace + * file. It might be better if drain-and-clear were atomic. + */ + ktrprocexit(td); + PROC_LOCK(p); + mtx_lock(&ktrace_mtx); + p->p_traceflag = 0; /* don't trace the vrele() */ + tracevp = p->p_tracevp; + p->p_tracevp = NULL; + tracecred = p->p_tracecred; + p->p_tracecred = NULL; + mtx_unlock(&ktrace_mtx); + PROC_UNLOCK(p); + if (tracevp != NULL) { + locked = VFS_LOCK_GIANT(tracevp->v_mount); + vrele(tracevp); + VFS_UNLOCK_GIANT(locked); + } + if (tracecred != NULL) + crfree(tracecred); +#endif + /* + * Release reference to text vnode + */ + if ((vtmp = p->p_textvp) != NULL) { + p->p_textvp = NULL; + locked = VFS_LOCK_GIANT(vtmp->v_mount); + vrele(vtmp); + VFS_UNLOCK_GIANT(locked); + } + + /* + * Release our limits structure. + */ + PROC_LOCK(p); + plim = p->p_limit; + p->p_limit = NULL; + PROC_UNLOCK(p); + lim_free(plim); + + /* + * 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); + + /* + * Reparent all of our children to init. + */ + 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 | P_STOPPED_TRACE); + psignal(q, SIGKILL); + } + PROC_UNLOCK(q); + } + + /* + * Save exit status and finalize rusage info except for times, + * adding in child rusage info later when our time is locked. + */ + PROC_LOCK(p); + p->p_xstat = rv; + p->p_xthread = td; + p->p_stats->p_ru.ru_nvcsw++; + *p->p_ru = p->p_stats->p_ru; + + /* + * Notify interested parties of our demise. + */ + KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); + + /* + * Just delete all entries in the p_klist. At this point we won't + * report any more events, and there are nasty race conditions that + * can beat us if we don't. + */ + knlist_clear(&p->p_klist, 1); + + /* + * 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); + mtx_lock(&p->p_pptr->p_sigacts->ps_mtx); + if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) { + struct proc *pp; + + mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); + pp = p->p_pptr; + PROC_UNLOCK(pp); + proc_reparent(p, initproc); + p->p_sigparent = SIGCHLD; + 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); + } else + mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); + + if (p->p_pptr == initproc) + psignal(p->p_pptr, SIGCHLD); + else if (p->p_sigparent != 0) { + if (p->p_sigparent == SIGCHLD) + childproc_exited(p); + else /* LINUX thread */ + psignal(p->p_pptr, p->p_sigparent); + } + 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); + PROC_UNLOCK(p); + + /* + * Finally, call machine-dependent code to release the remaining + * resources including address space. + * The address space is released by "vmspace_exitfree(p)" in + * vm_waitproc(). + */ + cpu_exit(td); + + WITNESS_WARN(WARN_PANIC, &proctree_lock.sx_object, + "process (pid %d) exiting", p->p_pid); + + PROC_LOCK(p); + PROC_LOCK(p->p_pptr); + sx_xunlock(&proctree_lock); + + /* + * We have to wait until after acquiring all locks before + * changing p_state. We need to avoid all possible context + * switches (including ones from blocking on a mutex) while + * marked as a zombie. We also have to set the zombie state + * before we release the parent process' proc lock to avoid + * a lost wakeup. So, we first call wakeup, then we grab the + * sched lock, update the state, and release the parent process' + * proc lock. + */ + wakeup(p->p_pptr); + mtx_lock_spin(&sched_lock); + p->p_state = PRS_ZOMBIE; + PROC_UNLOCK(p->p_pptr); + + ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); + + /* Do the same timestamp bookkeeping that mi_switch() would do. */ + binuptime(&new_switchtime); + bintime_add(&p->p_rux.rux_runtime, &new_switchtime); + bintime_sub(&p->p_rux.rux_runtime, PCPU_PTR(switchtime)); + PCPU_SET(switchtime, new_switchtime); + PCPU_SET(switchticks, ticks); + cnt.v_swtch++; + + sched_exit(p->p_pptr, td); + + /* + * Hopefully no one will try to deliver a signal to the process this + * late in the game. + */ + knlist_destroy(&p->p_klist); + + /* + * Make sure the scheduler takes this thread out of its tables etc. + * This will also release this thread's reference to the ucred. + * Other thread parts to release include pcb bits and such. + */ + thread_exit(); +} + + +#ifndef _SYS_SYSPROTO_H_ +struct abort2_args { + char *why; + int nargs; + void **args; +}; +#endif + +/* + * MPSAFE. + */ +int +abort2(struct thread *td, struct abort2_args *uap) +{ + struct proc *p = td->td_proc; + struct sbuf *sb; + void *uargs[16]; + int error, i, sig; + + error = 0; /* satisfy compiler */ + + /* + * Do it right now so we can log either proper call of abort2(), or + * note, that invalid argument was passed. 512 is big enough to + * handle 16 arguments' descriptions with additional comments. + */ + sb = sbuf_new(NULL, NULL, 512, SBUF_FIXEDLEN); + sbuf_clear(sb); + sbuf_printf(sb, "%s(pid %d uid %d) aborted: ", + p->p_comm, p->p_pid, td->td_ucred->cr_uid); + /* + * Since we can't return from abort2(), send SIGKILL in cases, where + * abort2() was called improperly + */ + sig = SIGKILL; + /* Prevent from DoSes from user-space. */ + if (uap->nargs < 0 || uap->nargs > 16) + goto out; + if (uap->args == NULL) + goto out; + error = copyin(uap->args, uargs, uap->nargs * sizeof(void *)); + if (error != 0) + goto out; + /* + * Limit size of 'reason' string to 128. Will fit even when + * maximal number of arguments was chosen to be logged. + */ + if (uap->why != NULL) { + error = sbuf_copyin(sb, uap->why, 128); + if (error < 0) + goto out; + } else { + sbuf_printf(sb, "(null)"); + } + if (uap->nargs) { + sbuf_printf(sb, "("); + for (i = 0;i < uap->nargs; i++) + sbuf_printf(sb, "%s%p", i == 0 ? "" : ", ", uargs[i]); + sbuf_printf(sb, ")"); + } + /* + * Final stage: arguments were proper, string has been + * successfully copied from userspace, and copying pointers + * from user-space succeed. + */ + sig = SIGABRT; +out: + if (sig == SIGKILL) { + sbuf_trim(sb); + sbuf_printf(sb, " (Reason text inaccessible)"); + } + sbuf_cat(sb, "\n"); + sbuf_finish(sb); + log(LOG_INFO, "%s", sbuf_data(sb)); + sbuf_delete(sb); + exit1(td, W_EXITCODE(0, sig)); + return (0); +} + + +#ifdef COMPAT_43 +/* + * The dirty work is handled by kern_wait(). + * + * MPSAFE. + */ +int +owait(struct thread *td, struct owait_args *uap __unused) +{ + int error, status; + + error = kern_wait(td, WAIT_ANY, &status, 0, NULL); + if (error == 0) + td->td_retval[1] = status; + return (error); +} +#endif /* COMPAT_43 */ + +/* + * The dirty work is handled by kern_wait(). + * + * MPSAFE. + */ +int +wait4(struct thread *td, struct wait_args *uap) +{ + struct rusage ru, *rup; + int error, status; + + if (uap->rusage != NULL) + rup = &ru; + else + rup = NULL; + error = kern_wait(td, uap->pid, &status, uap->options, rup); + if (uap->status != NULL && error == 0) + error = copyout(&status, uap->status, sizeof(status)); + if (uap->rusage != NULL && error == 0) + error = copyout(&ru, uap->rusage, sizeof(struct rusage)); + return (error); +} + +int +kern_wait(struct thread *td, pid_t pid, int *status, int options, + struct rusage *rusage) +{ + struct proc *p, *q, *t; + int error, nfound; + + q = td->td_proc; + if (pid == 0) { + PROC_LOCK(q); + pid = -q->p_pgid; + PROC_UNLOCK(q); + } + if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE)) + return (EINVAL); +loop: + if (q->p_flag & P_STATCHILD) { + PROC_LOCK(q); + q->p_flag &= ~P_STATCHILD; + PROC_UNLOCK(q); + } + nfound = 0; + sx_xlock(&proctree_lock); + LIST_FOREACH(p, &q->p_children, p_sibling) { + PROC_LOCK(p); + if (pid != WAIT_ANY && + p->p_pid != pid && p->p_pgid != -pid) { + PROC_UNLOCK(p); + continue; + } + if (p_canwait(td, p)) { + 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) ^ + ((options & WLINUXCLONE) != 0)) { + PROC_UNLOCK(p); + continue; + } + + nfound++; + if (p->p_state == PRS_ZOMBIE) { + + /* + * It is possible that the last thread of this + * process is still running on another CPU + * in thread_exit() after having dropped the process + * lock via PROC_UNLOCK() but before it has completed + * cpu_throw(). In that case, the other thread must + * still hold sched_lock, so simply by acquiring + * sched_lock once we will wait long enough for the + * thread to exit in that case. + */ + mtx_lock_spin(&sched_lock); + mtx_unlock_spin(&sched_lock); + + td->td_retval[0] = p->p_pid; + if (status) + *status = p->p_xstat; /* convert to int */ + if (rusage) { + *rusage = *p->p_ru; + calcru(p, &rusage->ru_utime, &rusage->ru_stime); + } + + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + + /* + * If we got the child via a ptrace 'attach', + * we need to give it back to the old parent. + */ + PROC_UNLOCK(p); + if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) { + PROC_LOCK(p); + p->p_oppid = 0; + proc_reparent(p, t); + PROC_UNLOCK(p); + tdsignal(t, NULL, SIGCHLD, p->p_ksi); + wakeup(t); + PROC_UNLOCK(t); + sx_xunlock(&proctree_lock); + return (0); + } + + /* + * Remove other references to this process to ensure + * we have an exclusive reference. + */ + sx_xlock(&allproc_lock); + LIST_REMOVE(p, p_list); /* off zombproc */ + sx_xunlock(&allproc_lock); + LIST_REMOVE(p, p_sibling); + leavepgrp(p); + 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, &q->p_crux, p->p_ru, + &p->p_rux); + 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 credentials, arguments, and sigacts. + */ + crfree(p->p_ucred); + p->p_ucred = NULL; + pargs_drop(p->p_args); + p->p_args = NULL; + sigacts_free(p->p_sigacts); + p->p_sigacts = NULL; + + /* + * Do any thread-system specific cleanups. + */ + thread_wait(p); + + /* + * 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); +#ifdef MAC + mac_destroy_proc(p); +#endif +#ifdef AUDIT + audit_proc_free(p); +#endif + KASSERT(FIRST_THREAD_IN_PROC(p), + ("kern_wait: no residual thread!")); + uma_zfree(proc_zone, p); + sx_xlock(&allproc_lock); + nprocs--; + sx_xunlock(&allproc_lock); + return (0); + } + mtx_lock_spin(&sched_lock); + if ((p->p_flag & P_STOPPED_SIG) && + (p->p_suspcount == p->p_numthreads) && + (p->p_flag & P_WAITED) == 0 && + (p->p_flag & P_TRACED || options & WUNTRACED)) { + mtx_unlock_spin(&sched_lock); + p->p_flag |= P_WAITED; + sx_xunlock(&proctree_lock); + td->td_retval[0] = p->p_pid; + if (status) + *status = W_STOPCODE(p->p_xstat); + PROC_UNLOCK(p); + + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + + return (0); + } + mtx_unlock_spin(&sched_lock); + if (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); + + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + + if (status) + *status = SIGCONT; + return (0); + } + PROC_UNLOCK(p); + } + if (nfound == 0) { + sx_xunlock(&proctree_lock); + return (ECHILD); + } + if (options & WNOHANG) { + sx_xunlock(&proctree_lock); + td->td_retval[0] = 0; + return (0); + } + PROC_LOCK(q); + sx_xunlock(&proctree_lock); + if (q->p_flag & P_STATCHILD) { + q->p_flag &= ~P_STATCHILD; + error = 0; + } else + error = msleep(q, &q->p_mtx, PWAIT | PCATCH, "wait", 0); + PROC_UNLOCK(q); + if (error) + 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(struct proc *child, 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; +} |
