/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */ /* * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_fork.c 8.8 (Berkeley) 2/14/95 */ #include <sys/param.h> #include <sys/systm.h> #include <sys/filedesc.h> #include <sys/kernel.h> #include <sys/malloc.h> #include <sys/proc.h> #include <sys/user.h> #include <sys/resourcevar.h> #include <sys/vnode.h> #include <sys/file.h> #include <sys/acct.h> #include <sys/ktrace.h> #include <mach/mach_types.h> #include <kern/mach_param.h> #include <machine/spl.h> thread_t cloneproc(struct proc *, int); thread_t procdup(); #define DOFORK 0x1 /* fork() system call */ #define DOVFORK 0x2 /* vfork() system call */ static int fork1(struct proc *, long, register_t *); /* * fork system call. */ int fork(p, uap, retval) struct proc *p; void *uap; register_t *retval; { return (fork1(p, (long)DOFORK, retval)); } /* * vfork system call */ int vfork(p, uap, retval) struct proc *p; void *uap; register_t *retval; { return (fork1(p, (long)DOVFORK, retval)); } static int fork1(p1, flags, retval) struct proc *p1; long flags; register_t *retval; { register struct proc *p2; register uid_t uid; thread_t newth, self = current_thread(); int s, count; task_t t; /* * 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 process; don't let root * exceed the limit. The variable nprocs is the current number of * processes, maxproc is the limit. */ uid = p1->p_cred->p_ruid; if ((nprocs >= maxproc - 1 && uid != 0) || nprocs >= maxproc) { tablefull("proc"); retval[1] = 0; return (EAGAIN); } /* * Increment the count of procs running with this uid. Don't allow * a nonprivileged user to exceed their current limit. */ count = chgproccnt(uid, 1); if (uid != 0 && count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur) { (void)chgproccnt(uid, -1); return (EAGAIN); } /* The newly created process comes with signal lock held */ newth = cloneproc(p1, 1); thread_dup(current_act(), newth); /* p2 = newth->task->proc; */ p2 = (struct proc *)(get_bsdtask_info(get_threadtask(newth))); thread_set_child(newth, p2->p_pid); s = splhigh(); p2->p_stats->p_start = time; splx(s); p2->p_acflag = AFORK; /* * Preserve synchronization semantics of vfork. If waiting for * child to exec or exit, set P_PPWAIT on child, and sleep on our * proc (in case of exit). */ if (flags == DOVFORK) p2->p_flag |= P_PPWAIT; /* drop the signal lock on the child */ signal_unlock(p2); (void) thread_resume(newth); /* drop the extra references we got during the creation */ if (t = get_threadtask(newth)) { task_deallocate(t); } act_deallocate(newth); while (p2->p_flag & P_PPWAIT) tsleep(p1, PWAIT, "ppwait", 0); retval[0] = p2->p_pid; retval[1] = 0; /* mark parent */ return (0); } /* * cloneproc() * * Create a new process from a specified process. * On return newly created child process has signal * lock held to block delivery of signal to it if called with * lock set. fork() code needs to explicity remove this lock * before signals can be delivered */ thread_t cloneproc(p1, lock) register struct proc *p1; register int lock; { register struct proc *p2, *newproc; static int nextpid = 0, pidchecked = 0; thread_t th; /* Allocate new proc. */ MALLOC_ZONE(newproc, struct proc *, sizeof *newproc, M_PROC, M_WAITOK); MALLOC_ZONE(newproc->p_cred, struct pcred *, sizeof *newproc->p_cred, M_SUBPROC, M_WAITOK); MALLOC_ZONE(newproc->p_stats, struct pstats *, sizeof *newproc->p_stats, M_SUBPROC, M_WAITOK); MALLOC_ZONE(newproc->p_sigacts, struct sigacts *, sizeof *newproc->p_sigacts, M_SUBPROC, M_WAITOK); /* * Find an unused process ID. We remember a range of unused IDs * ready to use (from nextpid+1 through pidchecked-1). */ nextpid++; 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 (nextpid >= PID_MAX) { nextpid = 100; pidchecked = 0; } if (nextpid >= 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 nextpid, so we can avoid checking for a while. */ p2 = allproc.lh_first; again: for (; p2 != 0; p2 = p2->p_list.le_next) { while (p2->p_pid == nextpid || p2->p_pgrp->pg_id == nextpid) { nextpid++; if (nextpid >= pidchecked) goto retry; } if (p2->p_pid > nextpid && pidchecked > p2->p_pid) pidchecked = p2->p_pid; if (p2->p_pgrp && p2->p_pgrp->pg_id > nextpid && pidchecked > p2->p_pgrp->pg_id) pidchecked = p2->p_pgrp->pg_id; } if (!doingzomb) { doingzomb = 1; p2 = zombproc.lh_first; goto again; } } nprocs++; p2 = newproc; p2->p_stat = SIDL; p2->p_pid = nextpid; /* * 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. */ bzero(&p2->p_startzero, (unsigned) ((caddr_t)&p2->p_endzero - (caddr_t)&p2->p_startzero)); bcopy(&p1->p_startcopy, &p2->p_startcopy, (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy)); p2->vm_shm = (void *)NULL; /* Make sure it is zero */ /* * Duplicate sub-structures as needed. * Increase reference counts on shared objects. * The p_stats and p_sigacts substructs are set in vm_fork. */ p2->p_flag = P_INMEM; if (p1->p_flag & P_PROFIL) startprofclock(p2); bcopy(p1->p_cred, p2->p_cred, sizeof(*p2->p_cred)); p2->p_cred->p_refcnt = 1; crhold(p1->p_ucred); lockinit(&p2->p_cred->pc_lock, PLOCK, "proc cred", 0, 0); /* bump references to the text vnode (for procfs) */ p2->p_textvp = p1->p_textvp; if (p2->p_textvp) VREF(p2->p_textvp); p2->p_fd = fdcopy(p1); if (p1->vm_shm) { shmfork(p1,p2); } /* * If p_limit is still copy-on-write, bump refcnt, * otherwise get a copy that won't be modified. * (If PL_SHAREMOD is clear, the structure is shared * copy-on-write.) */ if (p1->p_limit->p_lflags & PL_SHAREMOD) p2->p_limit = limcopy(p1->p_limit); else { p2->p_limit = p1->p_limit; p2->p_limit->p_refcnt++; } bzero(&p2->p_stats->pstat_startzero, (unsigned) ((caddr_t)&p2->p_stats->pstat_endzero - (caddr_t)&p2->p_stats->pstat_startzero)); bcopy(&p1->p_stats->pstat_startcopy, &p2->p_stats->pstat_startcopy, ((caddr_t)&p2->p_stats->pstat_endcopy - (caddr_t)&p2->p_stats->pstat_startcopy)); if (p1->p_sigacts != NULL) (void)memcpy(p2->p_sigacts, p1->p_sigacts, sizeof *p2->p_sigacts); else (void)memset(p2->p_sigacts, 0, sizeof *p2->p_sigacts); if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT) p2->p_flag |= P_CONTROLT; p2->p_xstat = 0; p2->p_ru = NULL; p2->p_debugger = 0; /* don't inherit */ lockinit(&p2->signal_lock, PVM, "signal", 0, 0); /* block all signals to reach the process */ if (lock) signal_lock(p2); p2->sigwait = FALSE; p2->sigwait_thread = NULL; p2->exit_thread = NULL; p2->user_stack = p1->user_stack; p2->p_sigpending = 0; #if KTRACE /* * Copy traceflag and tracefile if enabled. * If not inherited, these were zeroed above. */ if (p1->p_traceflag&KTRFAC_INHERIT) { p2->p_traceflag = p1->p_traceflag; if ((p2->p_tracep = p1->p_tracep) != NULL) VREF(p2->p_tracep); } #endif th = procdup(p2, p1); /* child, parent */ LIST_INSERT_AFTER(p1, p2, p_pglist); p2->p_pptr = p1; LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling); LIST_INIT(&p2->p_children); LIST_INSERT_HEAD(&allproc, p2, p_list); LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash); TAILQ_INIT(&p2->p_evlist); /* * Make child runnable, set start time. */ p2->p_stat = SRUN; return(th); } #include <kern/zalloc.h> struct zone *uthread_zone; int uthread_zone_inited = 0; void uthread_zone_init() { if (!uthread_zone_inited) { uthread_zone = zinit(sizeof(struct uthread), THREAD_MAX * sizeof(struct uthread), THREAD_CHUNK * sizeof(struct uthread), "uthreads"); uthread_zone_inited = 1; } } void * uthread_alloc(void) { void *ut; if (!uthread_zone_inited) uthread_zone_init(); ut = (void *)zalloc(uthread_zone); bzero(ut, sizeof(struct uthread)); return (ut); } void uthread_free(void *uthread) { struct _select *sel; struct uthread *uth = (struct uthread *)uthread; sel = &uth->uu_state.ss_select; /* cleanup the select bit space */ if (sel->nbytes) { FREE(sel->ibits, M_TEMP); FREE(sel->obits, M_TEMP); } /* and free the uthread itself */ zfree(uthread_zone, (vm_offset_t)uthread); }