diff options
Diffstat (limited to 'sys/kern/kern_exit.c')
-rw-r--r-- | sys/kern/kern_exit.c | 1261 |
1 files changed, 1261 insertions, 0 deletions
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c new file mode 100644 index 0000000..f0be10e --- /dev/null +++ b/sys/kern/kern_exit.c @@ -0,0 +1,1261 @@ +/*- + * 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_kdtrace.h" +#include "opt_ktrace.h" +#include "opt_procdesc.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/sysproto.h> +#include <sys/capability.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/procdesc.h> +#include <sys/pioctl.h> +#include <sys/jail.h> +#include <sys/tty.h> +#include <sys/wait.h> +#include <sys/vmmeter.h> +#include <sys/vnode.h> +#include <sys/racct.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/sdt.h> +#include <sys/shm.h> +#include <sys/sem.h> +#ifdef KTRACE +#include <sys/ktrace.h> +#endif + +#include <security/audit/audit.h> +#include <security/mac/mac_framework.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> + +#ifdef KDTRACE_HOOKS +#include <sys/dtrace_bsd.h> +dtrace_execexit_func_t dtrace_fasttrap_exit; +#endif + +SDT_PROVIDER_DECLARE(proc); +SDT_PROBE_DEFINE1(proc, kernel, , exit, exit, "int"); + +/* Hook for NFS teardown procedure. */ +void (*nlminfo_release_p)(struct proc *p); + +static void +clear_orphan(struct proc *p) +{ + + PROC_LOCK_ASSERT(p, MA_OWNED); + + if (p->p_flag & P_ORPHAN) { + LIST_REMOVE(p, p_orphan); + p->p_flag &= ~P_ORPHAN; + } +} + +/* + * exit -- death of process. + */ +void +sys_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 proc *p, *nq, *q; + struct vnode *vtmp; + struct vnode *ttyvp = NULL; + struct plimit *plim; + + mtx_assert(&Giant, MA_NOTOWNED); + + p = td->td_proc; + /* + * XXX in case we're rebooting we just let init die in order to + * work around an unsolved stack overflow seen very late during + * shutdown on sparc64 when the gmirror worker process exists. + */ + if (p == initproc && rebooting == 0) { + 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); + while (p->p_flag & P_HADTHREADS) { + /* + * First check if some other thread got here before us. + * If so, act appropriately: 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)) + break; + + /* + * All other activity in this process is now stopped. + * Threading support has been turned off. + */ + } + KASSERT(p->p_numthreads == 1, + ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); + racct_sub(p, RACCT_NTHR, 1); + /* + * Wakeup anyone in procfs' PIOCWAIT. They should have a hold + * on our vmspace, so we should block below until they have + * released their reference to us. Note that if they have + * requested S_EXIT stops we will block here until they ack + * via PIOCCONT. + */ + _STOPEVENT(p, S_EXIT, rv); + + /* + * Ignore any pending request to stop due to a stop signal. + * Once P_WEXIT is set, future requests will be ignored as + * well. + */ + p->p_flag &= ~P_STOPPED_SIG; + KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); + + /* + * Note that we are exiting and do another wakeup of anyone in + * PIOCWAIT in case they aren't listening for S_EXIT stops or + * decided to wait again after we told them we are exiting. + */ + p->p_flag |= P_WEXIT; + wakeup(&p->p_stype); + + /* + * Wait for any processes that have a hold on our vmspace to + * release their reference. + */ + while (p->p_lock > 0) + msleep(&p->p_lock, &p->p_mtx, PWAIT, "exithold", 0); + + p->p_xstat = rv; /* Let event handler change exit status */ + PROC_UNLOCK(p); + /* Drain the limit callout while we don't have the proc locked */ + callout_drain(&p->p_limco); + +#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); + kern_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); + } + + /* + * 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); + + /* + * If parent is waiting for us to exit or exec, + * P_PPWAIT is set; we will wakeup the parent below. + */ + PROC_LOCK(p); + rv = p->p_xstat; /* Event handler could change exit status */ + stopprofclock(p); + p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE); + + /* + * 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")); + } + PROC_UNLOCK(p); + + /* + * Reset any sigio structures pointing to us as a result of + * F_SETOWN with our pid. + */ + funsetownlst(&p->p_sigiolst); + + /* + * 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! + */ + fdescfree(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); + + vmspace_exit(td); + + sx_xlock(&proctree_lock); + if (SESS_LEADER(p)) { + struct session *sp = p->p_session; + struct tty *tp; + + /* + * 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(sp); + ttyvp = sp->s_ttyvp; + tp = sp->s_ttyp; + sp->s_ttyvp = NULL; + sp->s_ttydp = NULL; + sp->s_leader = NULL; + SESS_UNLOCK(sp); + + /* + * Signal foreground pgrp and revoke access to + * controlling terminal if it has not been revoked + * already. + * + * Because the TTY may have been revoked in the mean + * time and could already have a new session associated + * with it, make sure we don't send a SIGHUP to a + * foreground process group that does not belong to this + * session. + */ + + if (tp != NULL) { + tty_lock(tp); + if (tp->t_session == sp) + tty_signal_pgrp(tp, SIGHUP); + tty_unlock(tp); + } + + if (ttyvp != NULL) { + sx_xunlock(&proctree_lock); + if (vn_lock(ttyvp, LK_EXCLUSIVE) == 0) { + VOP_REVOKE(ttyvp, REVOKEALL); + VOP_UNLOCK(ttyvp, 0); + } + sx_xlock(&proctree_lock); + } + } + fixjobc(p, p->p_pgrp, 0); + sx_xunlock(&proctree_lock); + (void)acct_process(td); + + /* Release the TTY now we've unlocked everything. */ + if (ttyvp != NULL) + vrele(ttyvp); +#ifdef KTRACE + ktrprocexit(td); +#endif + /* + * Release reference to text vnode + */ + if ((vtmp = p->p_textvp) != NULL) { + p->p_textvp = NULL; + vrele(vtmp); + } + + /* + * Release our limits structure. + */ + PROC_LOCK(p); + plim = p->p_limit; + p->p_limit = NULL; + PROC_UNLOCK(p); + lim_free(plim); + + tidhash_remove(td); + + /* + * 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); + + /* + * Call machine-dependent code to release any + * machine-dependent resources other than the address space. + * The address space is released by "vmspace_exitfree(p)" in + * vm_waitproc(). + */ + cpu_exit(td); + + WITNESS_WARN(WARN_PANIC, NULL, "process (pid %d) exiting", p->p_pid); + + /* + * 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) { + struct thread *temp; + + /* + * Since q was found on our children list, the + * proc_reparent() call moved q to the orphan + * list due to present P_TRACED flag. Clear + * orphan link for q now while q is locked. + */ + clear_orphan(q); + q->p_flag &= ~(P_TRACED | P_STOPPED_TRACE); + FOREACH_THREAD_IN_PROC(q, temp) + temp->td_dbgflags &= ~TDB_SUSPEND; + kern_psignal(q, SIGKILL); + } + PROC_UNLOCK(q); + } + + /* + * Also get rid of our orphans. + */ + while ((q = LIST_FIRST(&p->p_orphans)) != NULL) { + PROC_LOCK(q); + clear_orphan(q); + PROC_UNLOCK(q); + } + + /* Save exit status. */ + PROC_LOCK(p); + p->p_xthread = td; + + /* Tell the prison that we are gone. */ + prison_proc_free(p->p_ucred->cr_prison); + +#ifdef KDTRACE_HOOKS + /* + * Tell the DTrace fasttrap provider about the exit if it + * has declared an interest. + */ + if (dtrace_fasttrap_exit) + dtrace_fasttrap_exit(p); +#endif + + /* + * Notify interested parties of our demise. + */ + KNOTE_LOCKED(&p->p_klist, NOTE_EXIT); + +#ifdef KDTRACE_HOOKS + int reason = CLD_EXITED; + if (WCOREDUMP(rv)) + reason = CLD_DUMPED; + else if (WIFSIGNALED(rv)) + reason = CLD_KILLED; + SDT_PROBE(proc, kernel, , exit, reason, 0, 0, 0, 0); +#endif + + /* + * 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); + + /* + * If this is a process with a descriptor, we may not need to deliver + * a signal to the parent. proctree_lock is held over + * procdesc_exit() to serialize concurrent calls to close() and + * exit(). + */ +#ifdef PROCDESC + if (p->p_procdesc == NULL || procdesc_exit(p)) { +#endif + /* + * 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); + + /* + * Notify parent, so in case he was wait(2)ing or + * executing waitpid(2) with our pid, he will + * continue. + */ + wakeup(pp); + } else + mtx_unlock(&p->p_pptr->p_sigacts->ps_mtx); + + if (p->p_pptr == initproc) + kern_psignal(p->p_pptr, SIGCHLD); + else if (p->p_sigparent != 0) { + if (p->p_sigparent == SIGCHLD) + childproc_exited(p); + else /* LINUX thread */ + kern_psignal(p->p_pptr, p->p_sigparent); + } +#ifdef PROCDESC + } else + PROC_LOCK(p->p_pptr); +#endif + sx_xunlock(&proctree_lock); + + /* + * The state PRS_ZOMBIE prevents other proesses from sending + * signal to the process, to avoid memory leak, we free memory + * for signal queue at the time when the state is set. + */ + sigqueue_flush(&p->p_sigqueue); + sigqueue_flush(&td->td_sigqueue); + + /* + * 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); + cv_broadcast(&p->p_pwait); + sched_exit(p->p_pptr, td); + PROC_SLOCK(p); + p->p_state = PRS_ZOMBIE; + PROC_UNLOCK(p->p_pptr); + + /* + * Hopefully no one will try to deliver a signal to the process this + * late in the game. + */ + knlist_destroy(&p->p_klist); + + /* + * Save our children's rusage information in our exit rusage. + */ + ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); + + /* + * 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 + +int +sys_abort2(struct thread *td, struct abort2_args *uap) +{ + struct proc *p = td->td_proc; + struct sbuf *sb; + void *uargs[16]; + int error, i, sig; + + /* + * 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->nargs > 0) { + 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 > 0) { + 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(). + */ +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(). + */ +int +sys_wait4(struct thread *td, struct wait4_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 +sys_wait6(struct thread *td, struct wait6_args *uap) +{ + struct __wrusage wru, *wrup; + siginfo_t si, *sip; + idtype_t idtype; + id_t id; + int error, status; + + idtype = uap->idtype; + id = uap->id; + + if (uap->wrusage != NULL) + wrup = &wru; + else + wrup = NULL; + + if (uap->info != NULL) { + sip = &si; + bzero(sip, sizeof(*sip)); + } else + sip = NULL; + + /* + * We expect all callers of wait6() to know about WEXITED and + * WTRAPPED. + */ + error = kern_wait6(td, idtype, id, &status, uap->options, wrup, sip); + + if (uap->status != NULL && error == 0) + error = copyout(&status, uap->status, sizeof(status)); + if (uap->wrusage != NULL && error == 0) + error = copyout(&wru, uap->wrusage, sizeof(wru)); + if (uap->info != NULL && error == 0) + error = copyout(&si, uap->info, sizeof(si)); + return (error); +} + +/* + * Reap the remains of a zombie process and optionally return status and + * rusage. Asserts and will release both the proctree_lock and the process + * lock as part of its work. + */ +void +proc_reap(struct thread *td, struct proc *p, int *status, int options) +{ + struct proc *q, *t; + + sx_assert(&proctree_lock, SA_XLOCKED); + PROC_LOCK_ASSERT(p, MA_OWNED); + PROC_SLOCK_ASSERT(p, MA_OWNED); + KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE")); + + q = td->td_proc; + + PROC_SUNLOCK(p); + td->td_retval[0] = p->p_pid; + if (status) + *status = p->p_xstat; /* convert to int */ + if (options & WNOWAIT) { + /* + * Only poll, returning the status. Caller does not wish to + * release the proc struct just yet. + */ + PROC_UNLOCK(p); + sx_xunlock(&proctree_lock); + return; + } + + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + 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); + proc_reparent(p, t); + p->p_oppid = 0; + PROC_UNLOCK(p); + pksignal(t, SIGCHLD, p->p_ksi); + wakeup(t); + cv_broadcast(&p->p_pwait); + PROC_UNLOCK(t); + sx_xunlock(&proctree_lock); + return; + } + + /* + * 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); + PROC_LOCK(p); + clear_orphan(p); + PROC_UNLOCK(p); + leavepgrp(p); +#ifdef PROCDESC + if (p->p_procdesc != NULL) + procdesc_reap(p); +#endif + 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); + + /* + * Decrement the count of procs running with this uid. + */ + (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0); + + /* + * Destroy resource accounting information associated with the process. + */ +#ifdef RACCT + PROC_LOCK(p); + racct_sub(p, RACCT_NPROC, 1); + PROC_UNLOCK(p); +#endif + racct_proc_exit(p); + + /* + * 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_proc_destroy(p); +#endif + KASSERT(FIRST_THREAD_IN_PROC(p), + ("proc_reap: no residual thread!")); + uma_zfree(proc_zone, p); + sx_xlock(&allproc_lock); + nprocs--; + sx_xunlock(&allproc_lock); +} + +static int +proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id, + int *status, int options, struct __wrusage *wrusage, siginfo_t *siginfo) +{ + struct proc *q; + struct rusage *rup; + + sx_assert(&proctree_lock, SA_XLOCKED); + + q = td->td_proc; + PROC_LOCK(p); + + switch (idtype) { + case P_ALL: + break; + case P_PID: + if (p->p_pid != (pid_t)id) { + PROC_UNLOCK(p); + return (0); + } + break; + case P_PGID: + if (p->p_pgid != (pid_t)id) { + PROC_UNLOCK(p); + return (0); + } + break; + case P_SID: + if (p->p_session->s_sid != (pid_t)id) { + PROC_UNLOCK(p); + return (0); + } + break; + case P_UID: + if (p->p_ucred->cr_uid != (uid_t)id) { + PROC_UNLOCK(p); + return (0); + } + break; + case P_GID: + if (p->p_ucred->cr_gid != (gid_t)id) { + PROC_UNLOCK(p); + return (0); + } + break; + case P_JAILID: + if (p->p_ucred->cr_prison->pr_id != (int)id) { + PROC_UNLOCK(p); + return (0); + } + break; + /* + * It seems that the thread structures get zeroed out + * at process exit. This makes it impossible to + * support P_SETID, P_CID or P_CPUID. + */ + default: + PROC_UNLOCK(p); + return (0); + } + + if (p_canwait(td, p)) { + PROC_UNLOCK(p); + return (0); + } + + if (((options & WEXITED) == 0) && (p->p_state == PRS_ZOMBIE)) { + PROC_UNLOCK(p); + return (0); + } + + /* + * 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); + return (0); + } + + PROC_SLOCK(p); + + if (siginfo != NULL) { + bzero(siginfo, sizeof(*siginfo)); + siginfo->si_errno = 0; + + /* + * SUSv4 requires that the si_signo value is always + * SIGCHLD. Obey it despite the rfork(2) interface + * allows to request other signal for child exit + * notification. + */ + siginfo->si_signo = SIGCHLD; + + /* + * This is still a rough estimate. We will fix the + * cases TRAPPED, STOPPED, and CONTINUED later. + */ + if (WCOREDUMP(p->p_xstat)) + siginfo->si_code = CLD_DUMPED; + else if (WIFSIGNALED(p->p_xstat)) + siginfo->si_code = CLD_KILLED; + else + siginfo->si_code = CLD_EXITED; + + siginfo->si_pid = p->p_pid; + siginfo->si_uid = p->p_ucred->cr_uid; + siginfo->si_status = p->p_xstat; + + /* + * The si_addr field would be useful additional + * detail, but apparently the PC value may be lost + * when we reach this point. bzero() above sets + * siginfo->si_addr to NULL. + */ + } + + /* + * There should be no reason to limit resources usage info to + * exited processes only. A snapshot about any resources used + * by a stopped process may be exactly what is needed. + */ + if (wrusage != NULL) { + rup = &wrusage->wru_self; + *rup = p->p_ru; + calcru(p, &rup->ru_utime, &rup->ru_stime); + + rup = &wrusage->wru_children; + *rup = p->p_stats->p_cru; + calccru(p, &rup->ru_utime, &rup->ru_stime); + } + + if (p->p_state == PRS_ZOMBIE) { + proc_reap(td, p, status, options); + return (-1); + } + PROC_SUNLOCK(p); + PROC_UNLOCK(p); + return (1); +} + +int +kern_wait(struct thread *td, pid_t pid, int *status, int options, + struct rusage *rusage) +{ + struct __wrusage wru, *wrup; + idtype_t idtype; + id_t id; + int ret; + + /* + * Translate the special pid values into the (idtype, pid) + * pair for kern_wait6. The WAIT_MYPGRP case is handled by + * kern_wait6() on its own. + */ + if (pid == WAIT_ANY) { + idtype = P_ALL; + id = 0; + } else if (pid < 0) { + idtype = P_PGID; + id = (id_t)-pid; + } else { + idtype = P_PID; + id = (id_t)pid; + } + + if (rusage != NULL) + wrup = &wru; + else + wrup = NULL; + + /* + * For backward compatibility we implicitly add flags WEXITED + * and WTRAPPED here. + */ + options |= WEXITED | WTRAPPED; + ret = kern_wait6(td, idtype, id, status, options, wrup, NULL); + if (rusage != NULL) + *rusage = wru.wru_self; + return (ret); +} + +int +kern_wait6(struct thread *td, idtype_t idtype, id_t id, int *status, + int options, struct __wrusage *wrusage, siginfo_t *siginfo) +{ + struct proc *p, *q; + int error, nfound, ret; + + AUDIT_ARG_VALUE((int)idtype); /* XXX - This is likely wrong! */ + AUDIT_ARG_PID((pid_t)id); /* XXX - This may be wrong! */ + AUDIT_ARG_VALUE(options); + + q = td->td_proc; + + if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { + PROC_LOCK(q); + id = (id_t)q->p_pgid; + PROC_UNLOCK(q); + idtype = P_PGID; + } + + /* If we don't know the option, just return. */ + if ((options & ~(WUNTRACED | WNOHANG | WCONTINUED | WNOWAIT | + WEXITED | WTRAPPED | WLINUXCLONE)) != 0) + return (EINVAL); + if ((options & (WEXITED | WUNTRACED | WCONTINUED | WTRAPPED)) == 0) { + /* + * We will be unable to find any matching processes, + * because there are no known events to look for. + * Prefer to return error instead of blocking + * indefinitely. + */ + 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) { + ret = proc_to_reap(td, p, idtype, id, status, options, + wrusage, siginfo); + if (ret == 0) + continue; + else if (ret == 1) + nfound++; + else + return (0); + + PROC_LOCK(p); + PROC_SLOCK(p); + + if ((options & WTRAPPED) != 0 && + (p->p_flag & P_TRACED) != 0 && + (p->p_flag & (P_STOPPED_TRACE | P_STOPPED_SIG)) != 0 && + (p->p_suspcount == p->p_numthreads) && + ((p->p_flag & P_WAITED) == 0)) { + PROC_SUNLOCK(p); + if ((options & WNOWAIT) == 0) + p->p_flag |= P_WAITED; + sx_xunlock(&proctree_lock); + td->td_retval[0] = p->p_pid; + + if (status != NULL) + *status = W_STOPCODE(p->p_xstat); + if (siginfo != NULL) { + siginfo->si_status = p->p_xstat; + siginfo->si_code = CLD_TRAPPED; + } + if ((options & WNOWAIT) == 0) { + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + } + + PROC_UNLOCK(p); + return (0); + } + if ((options & WUNTRACED) != 0 && + (p->p_flag & P_STOPPED_SIG) != 0 && + (p->p_suspcount == p->p_numthreads) && + ((p->p_flag & P_WAITED) == 0)) { + PROC_SUNLOCK(p); + if ((options & WNOWAIT) == 0) + p->p_flag |= P_WAITED; + sx_xunlock(&proctree_lock); + td->td_retval[0] = p->p_pid; + + if (status != NULL) + *status = W_STOPCODE(p->p_xstat); + if (siginfo != NULL) { + siginfo->si_status = p->p_xstat; + siginfo->si_code = CLD_STOPPED; + } + if ((options & WNOWAIT) == 0) { + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + } + + PROC_UNLOCK(p); + return (0); + } + PROC_SUNLOCK(p); + if ((options & WCONTINUED) != 0 && + (p->p_flag & P_CONTINUED) != 0) { + sx_xunlock(&proctree_lock); + td->td_retval[0] = p->p_pid; + if ((options & WNOWAIT) == 0) { + p->p_flag &= ~P_CONTINUED; + PROC_LOCK(q); + sigqueue_take(p->p_ksi); + PROC_UNLOCK(q); + } + PROC_UNLOCK(p); + + if (status != NULL) + *status = SIGCONT; + if (siginfo != NULL) { + siginfo->si_status = SIGCONT; + siginfo->si_code = CLD_CONTINUED; + } + return (0); + } + PROC_UNLOCK(p); + } + + /* + * Look in the orphans list too, to allow the parent to + * collect it's child exit status even if child is being + * debugged. + * + * Debugger detaches from the parent upon successful + * switch-over from parent to child. At this point due to + * re-parenting the parent loses the child to debugger and a + * wait4(2) call would report that it has no children to wait + * for. By maintaining a list of orphans we allow the parent + * to successfully wait until the child becomes a zombie. + */ + LIST_FOREACH(p, &q->p_orphans, p_orphan) { + ret = proc_to_reap(td, p, idtype, id, status, options, + wrusage, siginfo); + if (ret == 0) + continue; + else if (ret == 1) + nfound++; + else + return (0); + } + 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; + + PROC_LOCK(child->p_pptr); + sigqueue_take(child->p_ksi); + PROC_UNLOCK(child->p_pptr); + LIST_REMOVE(child, p_sibling); + LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); + + clear_orphan(child); + if (child->p_flag & P_TRACED) { + LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child, p_orphan); + child->p_flag |= P_ORPHAN; + } + + child->p_pptr = parent; +} |