Index: head/sys/kern/kern_exit.c =================================================================== --- head/sys/kern/kern_exit.c (revision 289025) +++ head/sys/kern/kern_exit.c (revision 289026) @@ -1,1381 +1,1379 @@ /*- * 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 __FBSDID("$FreeBSD$"); #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 #include #include #include #include #include #include #include #include #include /* for acct_process() function prototype */ #include #include #include #include #include #ifdef KTRACE #include #endif #include #include #include #include #include #include #include #include #include #include #ifdef KDTRACE_HOOKS #include dtrace_execexit_func_t dtrace_fasttrap_exit; #endif SDT_PROVIDER_DECLARE(proc); SDT_PROBE_DEFINE1(proc, kernel, , exit, "int"); /* Hook for NFS teardown procedure. */ void (*nlminfo_release_p)(struct proc *p); struct proc * proc_realparent(struct proc *child) { struct proc *p, *parent; sx_assert(&proctree_lock, SX_LOCKED); if ((child->p_treeflag & P_TREE_ORPHANED) == 0) { if (child->p_oppid == 0 || child->p_pptr->p_pid == child->p_oppid) parent = child->p_pptr; else parent = initproc; return (parent); } for (p = child; (p->p_treeflag & P_TREE_FIRST_ORPHAN) == 0;) { /* Cannot use LIST_PREV(), since the list head is not known. */ p = __containerof(p->p_orphan.le_prev, struct proc, p_orphan.le_next); KASSERT((p->p_treeflag & P_TREE_ORPHANED) != 0, ("missing P_ORPHAN %p", p)); } parent = __containerof(p->p_orphan.le_prev, struct proc, p_orphans.lh_first); return (parent); } void reaper_abandon_children(struct proc *p, bool exiting) { struct proc *p1, *p2, *ptmp; sx_assert(&proctree_lock, SX_LOCKED); KASSERT(p != initproc, ("reaper_abandon_children for initproc")); if ((p->p_treeflag & P_TREE_REAPER) == 0) return; p1 = p->p_reaper; LIST_FOREACH_SAFE(p2, &p->p_reaplist, p_reapsibling, ptmp) { LIST_REMOVE(p2, p_reapsibling); p2->p_reaper = p1; p2->p_reapsubtree = p->p_reapsubtree; LIST_INSERT_HEAD(&p1->p_reaplist, p2, p_reapsibling); if (exiting && p2->p_pptr == p) { PROC_LOCK(p2); proc_reparent(p2, p1); PROC_UNLOCK(p2); } } KASSERT(LIST_EMPTY(&p->p_reaplist), ("p_reaplist not empty")); p->p_treeflag &= ~P_TREE_REAPER; } static void clear_orphan(struct proc *p) { struct proc *p1; sx_assert(&proctree_lock, SA_XLOCKED); if ((p->p_treeflag & P_TREE_ORPHANED) == 0) return; if ((p->p_treeflag & P_TREE_FIRST_ORPHAN) != 0) { p1 = LIST_NEXT(p, p_orphan); if (p1 != NULL) p1->p_treeflag |= P_TREE_FIRST_ORPHAN; p->p_treeflag &= ~P_TREE_FIRST_ORPHAN; } LIST_REMOVE(p, p_orphan); p->p_treeflag &= ~P_TREE_ORPHANED; } /* * exit -- death of process. */ void sys_sys_exit(struct thread *td, struct sys_exit_args *uap) { exit1(td, 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 rval, int signo) { struct proc *p, *nq, *q, *t; struct thread *tdt; struct vnode *ttyvp = NULL; mtx_assert(&Giant, MA_NOTOWNED); KASSERT(rval == 0 || signo == 0, ("exit1 rv %d sig %d", rval, signo)); 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", signo, rval); panic("Going nowhere without my init!"); } /* * Deref SU mp, since the thread does not return to userspace. */ if (softdep_ast_cleanup != NULL) softdep_ast_cleanup(); /* * MUST abort all other threads before proceeding past here. */ PROC_LOCK(p); /* * First check if some other thread or external request got * here before us. If so, act appropriately: exit or suspend. * We must ensure that stop requests are handled before we set * P_WEXIT. */ thread_suspend_check(0); while (p->p_flag & P_HADTHREADS) { /* * 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(p, SINGLE_EXIT)) /* * All other activity in this process is now * stopped. Threading support has been turned * off. */ break; /* * Recheck for new stop or suspend requests which * might appear while process lock was dropped in * thread_single(). */ thread_suspend_check(0); } KASSERT(p->p_numthreads == 1, ("exit1: proc %p exiting with %d threads", p, p->p_numthreads)); racct_sub(p, RACCT_NTHR, 1); /* Let event handler change exit status */ p->p_xexit = rval; p->p_xsig = signo; /* * 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, 0); /* * 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); 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(rval, 0); AUDIT_SYSCALL_EXIT(0, td); #endif /* Are we a task leader with peers? */ if (p->p_peers != NULL && 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. * Event handler could change exit status. * 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); 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. */ if (p->p_leader->p_peers != NULL) { mtx_lock(&ppeers_lock); if (p->p_leader->p_peers != NULL) { 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 (p->p_textvp != NULL) { vrele(p->p_textvp); p->p_textvp = NULL; } /* * Release our limits structure. */ lim_free(p->p_limit); p->p_limit = NULL; 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 children processes: * - traced ones to the original parent (or init if we are that parent) * - the rest 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(q->p_reaper); for (; q != NULL; q = nq) { nq = LIST_NEXT(q, p_sibling); PROC_LOCK(q); q->p_sigparent = SIGCHLD; if (!(q->p_flag & P_TRACED)) { proc_reparent(q, q->p_reaper); } else { /* * Traced processes are killed since their existence * means someone is screwing up. */ t = proc_realparent(q); if (t == p) { proc_reparent(q, q->p_reaper); } else { PROC_LOCK(t); proc_reparent(q, t); PROC_UNLOCK(t); } /* * 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, tdt) tdt->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); CTR2(KTR_PTRACE, "exit: pid %d, clearing orphan %d", p->p_pid, q->p_pid); 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(signo)) reason = CLD_DUMPED; else if (WIFSIGNALED(signo)) reason = CLD_KILLED; SDT_PROBE1(proc, kernel, , exit, reason); #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(). */ if (p->p_procdesc == NULL || procdesc_exit(p)) { /* * 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, p->p_reaper); 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 == p->p_reaper || p->p_pptr == initproc) childproc_exited(p); 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); } } else PROC_LOCK(p->p_pptr); 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); umtx_thread_exit(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. */ PROC_STATLOCK(p); ruadd(&p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux); PROC_STATUNLOCK(p); /* * 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, 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); if (status) *status = KW_EXITCODE(p->p_xexit, p->p_xsig); 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); /* * If we got the child via a ptrace 'attach', we need to give it back * to the old parent. */ if (p->p_oppid != 0 && p->p_oppid != p->p_pptr->p_pid) { PROC_UNLOCK(p); t = proc_realparent(p); PROC_LOCK(t); PROC_LOCK(p); CTR2(KTR_PTRACE, "wait: traced child %d moved back to parent %d", p->p_pid, t->p_pid); 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; } p->p_oppid = 0; PROC_UNLOCK(p); /* * 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); reaper_abandon_children(p, true); LIST_REMOVE(p, p_reapsibling); PROC_LOCK(p); clear_orphan(p); PROC_UNLOCK(p); leavepgrp(p); if (p->p_procdesc != NULL) procdesc_reap(p); sx_xunlock(&proctree_lock); /* * Removal from allproc list and process group list paired with * PROC_LOCK which was executed during that time should guarantee * nothing can reach this process anymore. As such further locking * is unnecessary. */ p->p_xexit = p->p_xsig = 0; /* XXX: why? */ 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 if (racct_enable) { 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); proc_set_cred(p, 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 /* * Free any domain policy that's still hiding around. */ vm_domain_policy_cleanup(&p->p_vm_dom_policy); 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); + atomic_add_int(&nprocs, -1); } 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, int check_only) { struct rusage *rup; sx_assert(&proctree_lock, SA_XLOCKED); PROC_LOCK(p); switch (idtype) { case P_ALL: if (p->p_procdesc != NULL) { PROC_UNLOCK(p); return (0); } 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); } 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_xsig)) { siginfo->si_code = CLD_DUMPED; siginfo->si_status = WTERMSIG(p->p_xsig); } else if (WIFSIGNALED(p->p_xsig)) { siginfo->si_code = CLD_KILLED; siginfo->si_status = WTERMSIG(p->p_xsig); } else { siginfo->si_code = CLD_EXITED; siginfo->si_status = p->p_xexit; } siginfo->si_pid = p->p_pid; siginfo->si_uid = p->p_ucred->cr_uid; /* * 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; PROC_STATLOCK(p); calcru(p, &rup->ru_utime, &rup->ru_stime); PROC_STATUNLOCK(p); rup = &wrusage->wru_children; *rup = p->p_stats->p_cru; calccru(p, &rup->ru_utime, &rup->ru_stime); } if (p->p_state == PRS_ZOMBIE && !check_only) { PROC_SLOCK(p); proc_reap(td, p, status, options); return (-1); } 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; pid_t pid; 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) { pid = p->p_pid; ret = proc_to_reap(td, p, idtype, id, status, options, wrusage, siginfo, 0); if (ret == 0) continue; else if (ret == 1) nfound++; else { td->td_retval[0] = pid; 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); if (status != NULL) *status = W_STOPCODE(p->p_xsig); if (siginfo != NULL) { siginfo->si_status = p->p_xsig; siginfo->si_code = CLD_TRAPPED; } if ((options & WNOWAIT) == 0) { PROC_LOCK(q); sigqueue_take(p->p_ksi); PROC_UNLOCK(q); } CTR4(KTR_PTRACE, "wait: returning trapped pid %d status %#x (xstat %d) xthread %d", p->p_pid, W_STOPCODE(p->p_xsig), p->p_xsig, p->p_xthread != NULL ? p->p_xthread->td_tid : -1); PROC_UNLOCK(p); td->td_retval[0] = pid; 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); if (status != NULL) *status = W_STOPCODE(p->p_xsig); if (siginfo != NULL) { siginfo->si_status = p->p_xsig; siginfo->si_code = CLD_STOPPED; } if ((options & WNOWAIT) == 0) { PROC_LOCK(q); sigqueue_take(p->p_ksi); PROC_UNLOCK(q); } PROC_UNLOCK(p); td->td_retval[0] = pid; return (0); } PROC_SUNLOCK(p); if ((options & WCONTINUED) != 0 && (p->p_flag & P_CONTINUED) != 0) { sx_xunlock(&proctree_lock); 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; } td->td_retval[0] = pid; 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. */ if (nfound == 0) { LIST_FOREACH(p, &q->p_orphans, p_orphan) { ret = proc_to_reap(td, p, idtype, id, NULL, options, NULL, NULL, 1); if (ret != 0) { KASSERT(ret != -1, ("reaped an orphan (pid %d)", (int)td->td_retval[0])); nfound++; break; } } } 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) { if (LIST_EMPTY(&child->p_pptr->p_orphans)) { child->p_treeflag |= P_TREE_FIRST_ORPHAN; LIST_INSERT_HEAD(&child->p_pptr->p_orphans, child, p_orphan); } else { LIST_INSERT_AFTER(LIST_FIRST(&child->p_pptr->p_orphans), child, p_orphan); } child->p_treeflag |= P_TREE_ORPHANED; } child->p_pptr = parent; } Index: head/sys/kern/kern_fork.c =================================================================== --- head/sys/kern/kern_fork.c (revision 289025) +++ head/sys/kern/kern_fork.c (revision 289026) @@ -1,1085 +1,1089 @@ /*- * 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_fork.c 8.6 (Berkeley) 4/8/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_ktrace.h" #include "opt_kstack_pages.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef KDTRACE_HOOKS #include dtrace_fork_func_t dtrace_fasttrap_fork; #endif SDT_PROVIDER_DECLARE(proc); SDT_PROBE_DEFINE3(proc, kernel, , create, "struct proc *", "struct proc *", "int"); #ifndef _SYS_SYSPROTO_H_ struct fork_args { int dummy; }; #endif /* ARGSUSED */ int sys_fork(struct thread *td, struct fork_args *uap) { int error; struct proc *p2; error = fork1(td, RFFDG | RFPROC, 0, &p2, NULL, 0, NULL); if (error == 0) { td->td_retval[0] = p2->p_pid; td->td_retval[1] = 0; } return (error); } /* ARGUSED */ int sys_pdfork(td, uap) struct thread *td; struct pdfork_args *uap; { int error, fd; struct proc *p2; /* * It is necessary to return fd by reference because 0 is a valid file * descriptor number, and the child needs to be able to distinguish * itself from the parent using the return value. */ error = fork1(td, RFFDG | RFPROC | RFPROCDESC, 0, &p2, &fd, uap->flags, NULL); if (error == 0) { td->td_retval[0] = p2->p_pid; td->td_retval[1] = 0; error = copyout(&fd, uap->fdp, sizeof(fd)); } return (error); } /* ARGSUSED */ int sys_vfork(struct thread *td, struct vfork_args *uap) { int error, flags; struct proc *p2; flags = RFFDG | RFPROC | RFPPWAIT | RFMEM; error = fork1(td, flags, 0, &p2, NULL, 0, NULL); if (error == 0) { td->td_retval[0] = p2->p_pid; td->td_retval[1] = 0; } return (error); } int sys_rfork(struct thread *td, struct rfork_args *uap) { struct proc *p2; int error; /* Don't allow kernel-only flags. */ if ((uap->flags & RFKERNELONLY) != 0) return (EINVAL); AUDIT_ARG_FFLAGS(uap->flags); error = fork1(td, uap->flags, 0, &p2, NULL, 0, NULL); if (error == 0) { td->td_retval[0] = p2 ? p2->p_pid : 0; td->td_retval[1] = 0; } return (error); } int nprocs = 1; /* process 0 */ int lastpid = 0; SYSCTL_INT(_kern, OID_AUTO, lastpid, CTLFLAG_RD, &lastpid, 0, "Last used PID"); /* * Random component to lastpid generation. We mix in a random factor to make * it a little harder to predict. We sanity check the modulus value to avoid * doing it in critical paths. Don't let it be too small or we pointlessly * waste randomness entropy, and don't let it be impossibly large. Using a * modulus that is too big causes a LOT more process table scans and slows * down fork processing as the pidchecked caching is defeated. */ static int randompid = 0; static int sysctl_kern_randompid(SYSCTL_HANDLER_ARGS) { int error, pid; error = sysctl_wire_old_buffer(req, sizeof(int)); if (error != 0) return(error); sx_xlock(&allproc_lock); pid = randompid; error = sysctl_handle_int(oidp, &pid, 0, req); if (error == 0 && req->newptr != NULL) { if (pid < 0 || pid > pid_max - 100) /* out of range */ pid = pid_max - 100; else if (pid < 2) /* NOP */ pid = 0; else if (pid < 100) /* Make it reasonable */ pid = 100; randompid = pid; } sx_xunlock(&allproc_lock); return (error); } SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_kern_randompid, "I", "Random PID modulus"); static int fork_findpid(int flags) { struct proc *p; int trypid; static int pidchecked = 0; /* * Requires allproc_lock in order to iterate over the list * of processes, and proctree_lock to access p_pgrp. */ sx_assert(&allproc_lock, SX_LOCKED); sx_assert(&proctree_lock, SX_LOCKED); /* * Find an unused process ID. We remember a range of unused IDs * ready to use (from lastpid+1 through pidchecked-1). * * If RFHIGHPID is set (used during system boot), do not allocate * low-numbered pids. */ trypid = lastpid + 1; if (flags & RFHIGHPID) { if (trypid < 10) trypid = 10; } else { if (randompid) trypid += arc4random() % randompid; } retry: /* * If the process ID prototype has wrapped around, * restart somewhat above 0, as the low-numbered procs * tend to include daemons that don't exit. */ if (trypid >= pid_max) { trypid = trypid % pid_max; if (trypid < 100) trypid += 100; pidchecked = 0; } if (trypid >= pidchecked) { int doingzomb = 0; pidchecked = PID_MAX; /* * Scan the active and zombie procs to check whether this pid * is in use. Remember the lowest pid that's greater * than trypid, so we can avoid checking for a while. * * Avoid reuse of the process group id, session id or * the reaper subtree id. Note that for process group * and sessions, the amount of reserved pids is * limited by process limit. For the subtree ids, the * id is kept reserved only while there is a * non-reaped process in the subtree, so amount of * reserved pids is limited by process limit times * two. */ p = LIST_FIRST(&allproc); again: for (; p != NULL; p = LIST_NEXT(p, p_list)) { while (p->p_pid == trypid || p->p_reapsubtree == trypid || (p->p_pgrp != NULL && (p->p_pgrp->pg_id == trypid || (p->p_session != NULL && p->p_session->s_sid == trypid)))) { trypid++; if (trypid >= pidchecked) goto retry; } if (p->p_pid > trypid && pidchecked > p->p_pid) pidchecked = p->p_pid; if (p->p_pgrp != NULL) { if (p->p_pgrp->pg_id > trypid && pidchecked > p->p_pgrp->pg_id) pidchecked = p->p_pgrp->pg_id; if (p->p_session != NULL && p->p_session->s_sid > trypid && pidchecked > p->p_session->s_sid) pidchecked = p->p_session->s_sid; } } if (!doingzomb) { doingzomb = 1; p = LIST_FIRST(&zombproc); goto again; } } /* * RFHIGHPID does not mess with the lastpid counter during boot. */ if (flags & RFHIGHPID) pidchecked = 0; else lastpid = trypid; return (trypid); } static int fork_norfproc(struct thread *td, int flags) { int error; struct proc *p1; KASSERT((flags & RFPROC) == 0, ("fork_norfproc called with RFPROC set")); p1 = td->td_proc; if (((p1->p_flag & (P_HADTHREADS|P_SYSTEM)) == P_HADTHREADS) && (flags & (RFCFDG | RFFDG))) { PROC_LOCK(p1); if (thread_single(p1, SINGLE_BOUNDARY)) { PROC_UNLOCK(p1); return (ERESTART); } PROC_UNLOCK(p1); } error = vm_forkproc(td, NULL, NULL, NULL, flags); if (error) goto fail; /* * Close all file descriptors. */ if (flags & RFCFDG) { struct filedesc *fdtmp; fdtmp = fdinit(td->td_proc->p_fd, false); fdescfree(td); p1->p_fd = fdtmp; } /* * Unshare file descriptors (from parent). */ if (flags & RFFDG) fdunshare(td); fail: if (((p1->p_flag & (P_HADTHREADS|P_SYSTEM)) == P_HADTHREADS) && (flags & (RFCFDG | RFFDG))) { PROC_LOCK(p1); thread_single_end(p1, SINGLE_BOUNDARY); PROC_UNLOCK(p1); } return (error); } static void do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2, struct vmspace *vm2, int pdflags) { struct proc *p1, *pptr; int p2_held, trypid; struct filedesc *fd; struct filedesc_to_leader *fdtol; struct sigacts *newsigacts; sx_assert(&proctree_lock, SX_SLOCKED); sx_assert(&allproc_lock, SX_XLOCKED); p2_held = 0; p1 = td->td_proc; - /* - * Increment the nprocs resource before blocking can occur. There - * are hard-limits as to the number of processes that can run. - */ - nprocs++; - trypid = fork_findpid(flags); sx_sunlock(&proctree_lock); p2->p_state = PRS_NEW; /* protect against others */ p2->p_pid = trypid; AUDIT_ARG_PID(p2->p_pid); LIST_INSERT_HEAD(&allproc, p2, p_list); allproc_gen++; LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash); tidhash_add(td2); PROC_LOCK(p2); PROC_LOCK(p1); sx_xunlock(&allproc_lock); bcopy(&p1->p_startcopy, &p2->p_startcopy, __rangeof(struct proc, p_startcopy, p_endcopy)); pargs_hold(p2->p_args); PROC_UNLOCK(p1); bzero(&p2->p_startzero, __rangeof(struct proc, p_startzero, p_endzero)); /* Tell the prison that we exist. */ prison_proc_hold(p2->p_ucred->cr_prison); PROC_UNLOCK(p2); /* * Malloc things while we don't hold any locks. */ if (flags & RFSIGSHARE) newsigacts = NULL; else newsigacts = sigacts_alloc(); /* * Copy filedesc. */ if (flags & RFCFDG) { fd = fdinit(p1->p_fd, false); fdtol = NULL; } else if (flags & RFFDG) { fd = fdcopy(p1->p_fd); fdtol = NULL; } else { fd = fdshare(p1->p_fd); if (p1->p_fdtol == NULL) p1->p_fdtol = filedesc_to_leader_alloc(NULL, NULL, p1->p_leader); if ((flags & RFTHREAD) != 0) { /* * Shared file descriptor table, and shared * process leaders. */ fdtol = p1->p_fdtol; FILEDESC_XLOCK(p1->p_fd); fdtol->fdl_refcount++; FILEDESC_XUNLOCK(p1->p_fd); } else { /* * Shared file descriptor table, and different * process leaders. */ fdtol = filedesc_to_leader_alloc(p1->p_fdtol, p1->p_fd, p2); } } /* * Make a proc table entry for the new process. * Start by zeroing the section of proc that is zero-initialized, * then copy the section that is copied directly from the parent. */ PROC_LOCK(p2); PROC_LOCK(p1); bzero(&td2->td_startzero, __rangeof(struct thread, td_startzero, td_endzero)); bcopy(&td->td_startcopy, &td2->td_startcopy, __rangeof(struct thread, td_startcopy, td_endcopy)); bcopy(&p2->p_comm, &td2->td_name, sizeof(td2->td_name)); td2->td_sigstk = td->td_sigstk; td2->td_flags = TDF_INMEM; td2->td_lend_user_pri = PRI_MAX; #ifdef VIMAGE td2->td_vnet = NULL; td2->td_vnet_lpush = NULL; #endif /* * Allow the scheduler to initialize the child. */ thread_lock(td); sched_fork(td, td2); thread_unlock(td); /* * Duplicate sub-structures as needed. * Increase reference counts on shared objects. */ p2->p_flag = P_INMEM; p2->p_flag2 = p1->p_flag2 & (P2_NOTRACE | P2_NOTRACE_EXEC); p2->p_swtick = ticks; if (p1->p_flag & P_PROFIL) startprofclock(p2); /* * Whilst the proc lock is held, copy the VM domain data out * using the VM domain method. */ vm_domain_policy_init(&p2->p_vm_dom_policy); vm_domain_policy_localcopy(&p2->p_vm_dom_policy, &p1->p_vm_dom_policy); if (flags & RFSIGSHARE) { p2->p_sigacts = sigacts_hold(p1->p_sigacts); } else { sigacts_copy(newsigacts, p1->p_sigacts); p2->p_sigacts = newsigacts; } if (flags & RFTSIGZMB) p2->p_sigparent = RFTSIGNUM(flags); else if (flags & RFLINUXTHPN) p2->p_sigparent = SIGUSR1; else p2->p_sigparent = SIGCHLD; p2->p_textvp = p1->p_textvp; p2->p_fd = fd; p2->p_fdtol = fdtol; if (p1->p_flag2 & P2_INHERIT_PROTECTED) { p2->p_flag |= P_PROTECTED; p2->p_flag2 |= P2_INHERIT_PROTECTED; } /* * p_limit is copy-on-write. Bump its refcount. */ lim_fork(p1, p2); thread_cow_get_proc(td2, p2); pstats_fork(p1->p_stats, p2->p_stats); PROC_UNLOCK(p1); PROC_UNLOCK(p2); /* Bump references to the text vnode (for procfs). */ if (p2->p_textvp) vref(p2->p_textvp); /* * Set up linkage for kernel based threading. */ if ((flags & RFTHREAD) != 0) { mtx_lock(&ppeers_lock); p2->p_peers = p1->p_peers; p1->p_peers = p2; p2->p_leader = p1->p_leader; mtx_unlock(&ppeers_lock); PROC_LOCK(p1->p_leader); if ((p1->p_leader->p_flag & P_WEXIT) != 0) { PROC_UNLOCK(p1->p_leader); /* * The task leader is exiting, so process p1 is * going to be killed shortly. Since p1 obviously * isn't dead yet, we know that the leader is either * sending SIGKILL's to all the processes in this * task or is sleeping waiting for all the peers to * exit. We let p1 complete the fork, but we need * to go ahead and kill the new process p2 since * the task leader may not get a chance to send * SIGKILL to it. We leave it on the list so that * the task leader will wait for this new process * to commit suicide. */ PROC_LOCK(p2); kern_psignal(p2, SIGKILL); PROC_UNLOCK(p2); } else PROC_UNLOCK(p1->p_leader); } else { p2->p_peers = NULL; p2->p_leader = p2; } sx_xlock(&proctree_lock); PGRP_LOCK(p1->p_pgrp); PROC_LOCK(p2); PROC_LOCK(p1); /* * Preserve some more flags in subprocess. P_PROFIL has already * been preserved. */ p2->p_flag |= p1->p_flag & P_SUGID; td2->td_pflags |= td->td_pflags & TDP_ALTSTACK; SESS_LOCK(p1->p_session); if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT) p2->p_flag |= P_CONTROLT; SESS_UNLOCK(p1->p_session); if (flags & RFPPWAIT) p2->p_flag |= P_PPWAIT; p2->p_pgrp = p1->p_pgrp; LIST_INSERT_AFTER(p1, p2, p_pglist); PGRP_UNLOCK(p1->p_pgrp); LIST_INIT(&p2->p_children); LIST_INIT(&p2->p_orphans); callout_init_mtx(&p2->p_itcallout, &p2->p_mtx, 0); /* * If PF_FORK is set, the child process inherits the * procfs ioctl flags from its parent. */ if (p1->p_pfsflags & PF_FORK) { p2->p_stops = p1->p_stops; p2->p_pfsflags = p1->p_pfsflags; } /* * This begins the section where we must prevent the parent * from being swapped. */ _PHOLD(p1); PROC_UNLOCK(p1); /* * Attach the new process to its parent. * * If RFNOWAIT is set, the newly created process becomes a child * of init. This effectively disassociates the child from the * parent. */ if ((flags & RFNOWAIT) != 0) { pptr = p1->p_reaper; p2->p_reaper = pptr; } else { p2->p_reaper = (p1->p_treeflag & P_TREE_REAPER) != 0 ? p1 : p1->p_reaper; pptr = p1; } p2->p_pptr = pptr; LIST_INSERT_HEAD(&pptr->p_children, p2, p_sibling); LIST_INIT(&p2->p_reaplist); LIST_INSERT_HEAD(&p2->p_reaper->p_reaplist, p2, p_reapsibling); if (p2->p_reaper == p1) p2->p_reapsubtree = p2->p_pid; sx_xunlock(&proctree_lock); /* Inform accounting that we have forked. */ p2->p_acflag = AFORK; PROC_UNLOCK(p2); #ifdef KTRACE ktrprocfork(p1, p2); #endif /* * Finish creating the child process. It will return via a different * execution path later. (ie: directly into user mode) */ vm_forkproc(td, p2, td2, vm2, flags); if (flags == (RFFDG | RFPROC)) { PCPU_INC(cnt.v_forks); PCPU_ADD(cnt.v_forkpages, p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize); } else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM)) { PCPU_INC(cnt.v_vforks); PCPU_ADD(cnt.v_vforkpages, p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize); } else if (p1 == &proc0) { PCPU_INC(cnt.v_kthreads); PCPU_ADD(cnt.v_kthreadpages, p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize); } else { PCPU_INC(cnt.v_rforks); PCPU_ADD(cnt.v_rforkpages, p2->p_vmspace->vm_dsize + p2->p_vmspace->vm_ssize); } /* * Associate the process descriptor with the process before anything * can happen that might cause that process to need the descriptor. * However, don't do this until after fork(2) can no longer fail. */ if (flags & RFPROCDESC) procdesc_new(p2, pdflags); /* * Both processes are set up, now check if any loadable modules want * to adjust anything. */ EVENTHANDLER_INVOKE(process_fork, p1, p2, flags); /* * Set the child start time and mark the process as being complete. */ PROC_LOCK(p2); PROC_LOCK(p1); microuptime(&p2->p_stats->p_start); PROC_SLOCK(p2); p2->p_state = PRS_NORMAL; PROC_SUNLOCK(p2); #ifdef KDTRACE_HOOKS /* * Tell the DTrace fasttrap provider about the new process so that any * tracepoints inherited from the parent can be removed. We have to do * this only after p_state is PRS_NORMAL since the fasttrap module will * use pfind() later on. */ if ((flags & RFMEM) == 0 && dtrace_fasttrap_fork) dtrace_fasttrap_fork(p1, p2); #endif if ((p1->p_flag & (P_TRACED | P_FOLLOWFORK)) == (P_TRACED | P_FOLLOWFORK)) { /* * Arrange for debugger to receive the fork event. * * We can report PL_FLAG_FORKED regardless of * P_FOLLOWFORK settings, but it does not make a sense * for runaway child. */ td->td_dbgflags |= TDB_FORK; td->td_dbg_forked = p2->p_pid; td2->td_dbgflags |= TDB_STOPATFORK; _PHOLD(p2); p2_held = 1; } if (flags & RFPPWAIT) { td->td_pflags |= TDP_RFPPWAIT; td->td_rfppwait_p = p2; } PROC_UNLOCK(p2); if ((flags & RFSTOPPED) == 0) { /* * If RFSTOPPED not requested, make child runnable and * add to run queue. */ thread_lock(td2); TD_SET_CAN_RUN(td2); sched_add(td2, SRQ_BORING); thread_unlock(td2); } /* * Now can be swapped. */ _PRELE(p1); PROC_UNLOCK(p1); /* * Tell any interested parties about the new process. */ knote_fork(&p1->p_klist, p2->p_pid); SDT_PROBE3(proc, kernel, , create, p2, p1, flags); /* * Wait until debugger is attached to child. */ PROC_LOCK(p2); while ((td2->td_dbgflags & TDB_STOPATFORK) != 0) cv_wait(&p2->p_dbgwait, &p2->p_mtx); if (p2_held) _PRELE(p2); PROC_UNLOCK(p2); } int fork1(struct thread *td, int flags, int pages, struct proc **procp, int *procdescp, int pdflags, struct filecaps *fcaps) { - struct proc *p1; - struct proc *newproc; - int ok; + struct proc *p1, *newproc; struct thread *td2; struct vmspace *vm2; + struct file *fp_procdesc; vm_ooffset_t mem_charged; - int error; + int error, nprocs_new, ok; static int curfail; static struct timeval lastfail; - struct file *fp_procdesc = NULL; /* Check for the undefined or unimplemented flags. */ if ((flags & ~(RFFLAGS | RFTSIGFLAGS(RFTSIGMASK))) != 0) return (EINVAL); /* Signal value requires RFTSIGZMB. */ if ((flags & RFTSIGFLAGS(RFTSIGMASK)) != 0 && (flags & RFTSIGZMB) == 0) return (EINVAL); /* Can't copy and clear. */ if ((flags & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG)) return (EINVAL); /* Check the validity of the signal number. */ if ((flags & RFTSIGZMB) != 0 && (u_int)RFTSIGNUM(flags) > _SIG_MAXSIG) return (EINVAL); if ((flags & RFPROCDESC) != 0) { /* Can't not create a process yet get a process descriptor. */ if ((flags & RFPROC) == 0) return (EINVAL); /* Must provide a place to put a procdesc if creating one. */ if (procdescp == NULL) return (EINVAL); } p1 = td->td_proc; /* * Here we don't create a new process, but we divorce * certain parts of a process from itself. */ if ((flags & RFPROC) == 0) { *procp = NULL; return (fork_norfproc(td, flags)); } + fp_procdesc = NULL; + newproc = NULL; + vm2 = NULL; + /* + * Increment the nprocs resource before allocations occur. + * Although process entries are dynamically created, we still + * keep a global limit on the maximum number we will + * create. There are hard-limits as to the number of processes + * that can run, established by the KVA and memory usage for + * the process data. + * + * Don't allow a nonprivileged user to use the last ten + * processes; don't let root exceed the limit. + */ + nprocs_new = atomic_fetchadd_int(&nprocs, 1) + 1; + if ((nprocs_new >= maxproc - 10 && priv_check_cred(td->td_ucred, + PRIV_MAXPROC, 0) != 0) || nprocs_new >= maxproc) { + error = EAGAIN; + sx_xlock(&allproc_lock); + if (ppsratecheck(&lastfail, &curfail, 1)) { + printf("maxproc limit exceeded by uid %u (pid %d); " + "see tuning(7) and login.conf(5)\n", + td->td_ucred->cr_ruid, p1->p_pid); + } + sx_xunlock(&allproc_lock); + goto fail2; + } + + /* * If required, create a process descriptor in the parent first; we * will abandon it if something goes wrong. We don't finit() until * later. */ if (flags & RFPROCDESC) { error = falloc_caps(td, &fp_procdesc, procdescp, 0, fcaps); if (error != 0) return (error); } mem_charged = 0; - vm2 = NULL; if (pages == 0) pages = kstack_pages; /* Allocate new proc. */ newproc = uma_zalloc(proc_zone, M_WAITOK); td2 = FIRST_THREAD_IN_PROC(newproc); if (td2 == NULL) { td2 = thread_alloc(pages); if (td2 == NULL) { error = ENOMEM; goto fail2; } proc_linkup(newproc, td2); } else { if (td2->td_kstack == 0 || td2->td_kstack_pages != pages) { if (td2->td_kstack != 0) vm_thread_dispose(td2); if (!thread_alloc_stack(td2, pages)) { error = ENOMEM; goto fail2; } } } if ((flags & RFMEM) == 0) { vm2 = vmspace_fork(p1->p_vmspace, &mem_charged); if (vm2 == NULL) { error = ENOMEM; goto fail2; } if (!swap_reserve(mem_charged)) { /* * The swap reservation failed. The accounting * from the entries of the copied vm2 will be * substracted in vmspace_free(), so force the * reservation there. */ swap_reserve_force(mem_charged); error = ENOMEM; goto fail2; } } else vm2 = NULL; /* * XXX: This is ugly; when we copy resource usage, we need to bump * per-cred resource counters. */ proc_set_cred_init(newproc, crhold(td->td_ucred)); /* * Initialize resource accounting for the child process. */ error = racct_proc_fork(p1, newproc); if (error != 0) { error = EAGAIN; goto fail1; } #ifdef MAC mac_proc_init(newproc); #endif knlist_init_mtx(&newproc->p_klist, &newproc->p_mtx); STAILQ_INIT(&newproc->p_ktr); /* We have to lock the process tree while we look for a pid. */ sx_slock(&proctree_lock); - - /* - * Although process entries are dynamically created, we still keep - * a global limit on the maximum number we will create. Don't allow - * a nonprivileged user to use the last ten processes; don't let root - * exceed the limit. The variable nprocs is the current number of - * processes, maxproc is the limit. - */ sx_xlock(&allproc_lock); - if ((nprocs >= maxproc - 10 && priv_check_cred(td->td_ucred, - PRIV_MAXPROC, 0) != 0) || nprocs >= maxproc) { - error = EAGAIN; - goto fail; - } /* * Increment the count of procs running with this uid. Don't allow * a nonprivileged user to exceed their current limit. * * XXXRW: Can we avoid privilege here if it's not needed? */ error = priv_check_cred(td->td_ucred, PRIV_PROC_LIMIT, 0); if (error == 0) ok = chgproccnt(td->td_ucred->cr_ruidinfo, 1, 0); else { ok = chgproccnt(td->td_ucred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPROC)); } if (ok) { do_fork(td, flags, newproc, td2, vm2, pdflags); /* * Return child proc pointer to parent. */ *procp = newproc; if (flags & RFPROCDESC) { procdesc_finit(newproc->p_procdesc, fp_procdesc); fdrop(fp_procdesc, td); } racct_proc_fork_done(newproc); return (0); } error = EAGAIN; -fail: sx_sunlock(&proctree_lock); - if (ppsratecheck(&lastfail, &curfail, 1)) - printf("maxproc limit exceeded by uid %u (pid %d); see tuning(7) and login.conf(5)\n", - td->td_ucred->cr_ruid, p1->p_pid); sx_xunlock(&allproc_lock); #ifdef MAC mac_proc_destroy(newproc); #endif racct_proc_exit(newproc); fail1: crfree(newproc->p_ucred); newproc->p_ucred = NULL; fail2: if (vm2 != NULL) vmspace_free(vm2); uma_zfree(proc_zone, newproc); if ((flags & RFPROCDESC) != 0 && fp_procdesc != NULL) { fdclose(td, fp_procdesc, *procdescp); fdrop(fp_procdesc, td); } + atomic_add_int(&nprocs, -1); pause("fork", hz / 2); return (error); } /* * Handle the return of a child process from fork1(). This function * is called from the MD fork_trampoline() entry point. */ void fork_exit(void (*callout)(void *, struct trapframe *), void *arg, struct trapframe *frame) { struct proc *p; struct thread *td; struct thread *dtd; td = curthread; p = td->td_proc; KASSERT(p->p_state == PRS_NORMAL, ("executing process is still new")); CTR4(KTR_PROC, "fork_exit: new thread %p (td_sched %p, pid %d, %s)", td, td->td_sched, p->p_pid, td->td_name); sched_fork_exit(td); /* * Processes normally resume in mi_switch() after being * cpu_switch()'ed to, but when children start up they arrive here * instead, so we must do much the same things as mi_switch() would. */ if ((dtd = PCPU_GET(deadthread))) { PCPU_SET(deadthread, NULL); thread_stash(dtd); } thread_unlock(td); /* * cpu_set_fork_handler intercepts this function call to * have this call a non-return function to stay in kernel mode. * initproc has its own fork handler, but it does return. */ KASSERT(callout != NULL, ("NULL callout in fork_exit")); callout(arg, frame); /* * Check if a kernel thread misbehaved and returned from its main * function. */ if (p->p_flag & P_KTHREAD) { printf("Kernel thread \"%s\" (pid %d) exited prematurely.\n", td->td_name, p->p_pid); kproc_exit(0); } mtx_assert(&Giant, MA_NOTOWNED); if (p->p_sysent->sv_schedtail != NULL) (p->p_sysent->sv_schedtail)(td); } /* * Simplified back end of syscall(), used when returning from fork() * directly into user mode. Giant is not held on entry, and must not * be held on return. This function is passed in to fork_exit() as the * first parameter and is called when returning to a new userland process. */ void fork_return(struct thread *td, struct trapframe *frame) { struct proc *p, *dbg; p = td->td_proc; if (td->td_dbgflags & TDB_STOPATFORK) { sx_xlock(&proctree_lock); PROC_LOCK(p); if ((p->p_pptr->p_flag & (P_TRACED | P_FOLLOWFORK)) == (P_TRACED | P_FOLLOWFORK)) { /* * If debugger still wants auto-attach for the * parent's children, do it now. */ dbg = p->p_pptr->p_pptr; p->p_flag |= P_TRACED; p->p_oppid = p->p_pptr->p_pid; CTR2(KTR_PTRACE, "fork_return: attaching to new child pid %d: oppid %d", p->p_pid, p->p_oppid); proc_reparent(p, dbg); sx_xunlock(&proctree_lock); td->td_dbgflags |= TDB_CHILD | TDB_SCX; ptracestop(td, SIGSTOP); td->td_dbgflags &= ~(TDB_CHILD | TDB_SCX); } else { /* * ... otherwise clear the request. */ sx_xunlock(&proctree_lock); td->td_dbgflags &= ~TDB_STOPATFORK; cv_broadcast(&p->p_dbgwait); } PROC_UNLOCK(p); } else if (p->p_flag & P_TRACED) { /* * This is the start of a new thread in a traced * process. Report a system call exit event. */ PROC_LOCK(p); td->td_dbgflags |= TDB_SCX; _STOPEVENT(p, S_SCX, td->td_dbg_sc_code); if ((p->p_stops & S_PT_SCX) != 0) ptracestop(td, SIGTRAP); td->td_dbgflags &= ~TDB_SCX; PROC_UNLOCK(p); } userret(td, frame); #ifdef KTRACE if (KTRPOINT(td, KTR_SYSRET)) ktrsysret(SYS_fork, 0, 0); #endif }