xref: /netbsd-src/sys/kern/init_main.c (revision 5b239d0be1d6682ecf6030411841b40cc91e8b34)
1 /*	$NetBSD: init_main.c,v 1.280 2006/11/11 02:12:53 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
37  */
38 
39 /*
40  * Copyright (c) 1995 Christopher G. Demetriou.  All rights reserved.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 3. All advertising materials mentioning features or use of this software
51  *    must display the following acknowledgement:
52  *	This product includes software developed by the University of
53  *	California, Berkeley and its contributors.
54  * 4. Neither the name of the University nor the names of its contributors
55  *    may be used to endorse or promote products derived from this software
56  *    without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68  * SUCH DAMAGE.
69  *
70  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
71  */
72 
73 #include <sys/cdefs.h>
74 __KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.280 2006/11/11 02:12:53 christos Exp $");
75 
76 #include "opt_ipsec.h"
77 #include "opt_kcont.h"
78 #include "opt_multiprocessor.h"
79 #include "opt_ntp.h"
80 #include "opt_pipe.h"
81 #include "opt_posix.h"
82 #include "opt_syscall_debug.h"
83 #include "opt_sysv.h"
84 #include "opt_fileassoc.h"
85 
86 #include "rnd.h"
87 #include "veriexec.h"
88 
89 #include <sys/param.h>
90 #include <sys/acct.h>
91 #include <sys/filedesc.h>
92 #include <sys/file.h>
93 #include <sys/errno.h>
94 #include <sys/callout.h>
95 #include <sys/kernel.h>
96 #include <sys/kcont.h>
97 #include <sys/kmem.h>
98 #include <sys/mount.h>
99 #include <sys/proc.h>
100 #include <sys/kthread.h>
101 #include <sys/resourcevar.h>
102 #include <sys/signalvar.h>
103 #include <sys/systm.h>
104 #include <sys/vnode.h>
105 #include <sys/tty.h>
106 #include <sys/conf.h>
107 #include <sys/disklabel.h>
108 #include <sys/buf.h>
109 #include <sys/device.h>
110 #include <sys/exec.h>
111 #include <sys/socketvar.h>
112 #include <sys/protosw.h>
113 #include <sys/reboot.h>
114 #include <sys/user.h>
115 #include <sys/sysctl.h>
116 #include <sys/event.h>
117 #include <sys/mbuf.h>
118 #ifdef FAST_IPSEC
119 #include <netipsec/ipsec.h>
120 #endif
121 #ifdef SYSVSHM
122 #include <sys/shm.h>
123 #endif
124 #ifdef SYSVSEM
125 #include <sys/sem.h>
126 #endif
127 #ifdef SYSVMSG
128 #include <sys/msg.h>
129 #endif
130 #ifdef P1003_1B_SEMAPHORE
131 #include <sys/ksem.h>
132 #endif
133 #include <sys/domain.h>
134 #include <sys/namei.h>
135 #if NRND > 0
136 #include <sys/rnd.h>
137 #endif
138 #ifndef PIPE_SOCKETPAIR
139 #include <sys/pipe.h>
140 #endif
141 #ifdef LKM
142 #include <sys/lkm.h>
143 #endif
144 #if NVERIEXEC > 0
145 #include <sys/verified_exec.h>
146 #endif /* NVERIEXEC > 0 */
147 #include <sys/kauth.h>
148 #include <net80211/ieee80211_netbsd.h>
149 
150 #include <sys/syscall.h>
151 #include <sys/sa.h>
152 #include <sys/syscallargs.h>
153 
154 #ifdef FILEASSOC
155 #include <sys/fileassoc.h>
156 #endif /* FILEASSOC */
157 
158 #include <ufs/ufs/quota.h>
159 
160 #include <miscfs/genfs/genfs.h>
161 #include <miscfs/syncfs/syncfs.h>
162 
163 #include <machine/cpu.h>
164 
165 #include <uvm/uvm.h>
166 
167 #include <dev/cons.h>
168 
169 #include <net/if.h>
170 #include <net/raw_cb.h>
171 
172 #include <secmodel/secmodel.h>
173 
174 extern struct proc proc0;
175 extern struct lwp lwp0;
176 extern struct cwdinfo cwdi0;
177 
178 #ifndef curlwp
179 struct	lwp *curlwp = &lwp0;
180 #endif
181 struct	proc *initproc;
182 
183 struct	vnode *rootvp, *swapdev_vp;
184 int	boothowto;
185 int	cold = 1;			/* still working on startup */
186 struct timeval boottime;	        /* time at system startup - will only follow settime deltas */
187 time_t	rootfstime;			/* recorded root fs time, if known */
188 
189 volatile int start_init_exec;		/* semaphore for start_init() */
190 
191 static void check_console(struct lwp *l);
192 static void start_init(void *);
193 void main(void);
194 
195 #if defined(__SSP__) || defined(__SSP_ALL__)
196 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
197 void __stack_chk_fail(void);
198 
199 void
200 __stack_chk_fail(void)
201 {
202 	panic("stack overflow detected; terminated");
203 }
204 #endif
205 
206 /*
207  * System startup; initialize the world, create process 0, mount root
208  * filesystem, and fork to create init and pagedaemon.  Most of the
209  * hard work is done in the lower-level initialization routines including
210  * startup(), which does memory initialization and autoconfiguration.
211  */
212 void
213 main(void)
214 {
215 #ifdef __HAVE_TIMECOUNTER
216 	struct timeval time;
217 #endif
218 	struct lwp *l;
219 	struct proc *p;
220 	struct pdevinit *pdev;
221 	int s, error;
222 	extern struct pdevinit pdevinit[];
223 	extern void schedcpu(void *);
224 #ifdef NVNODE_IMPLICIT
225 	int usevnodes;
226 #endif
227 
228 	/*
229 	 * Initialize the current LWP pointer (curlwp) before
230 	 * any possible traps/probes to simplify trap processing.
231 	 */
232 	l = &lwp0;
233 	curlwp = l;
234 	l->l_cpu = curcpu();
235 	l->l_proc = &proc0;
236 	l->l_lid = 1;
237 
238 	/*
239 	 * Attempt to find console and initialize
240 	 * in case of early panic or other messages.
241 	 */
242 	consinit();
243 
244 	KERNEL_LOCK_INIT();
245 
246 	uvm_init();
247 
248 	kmem_init();
249 
250 	/* Do machine-dependent initialization. */
251 	cpu_startup();
252 
253 	/* Initialize callouts. */
254 	callout_startup();
255 
256 	/* Initialize the buffer cache */
257 	bufinit();
258 
259 	/*
260 	 * Initialize mbuf's.  Do this now because we might attempt to
261 	 * allocate mbufs or mbuf clusters during autoconfiguration.
262 	 */
263 	mbinit();
264 
265 	/* Initialize sockets. */
266 	soinit();
267 
268 #ifdef KCONT
269 	/* Initialize kcont. */
270         kcont_init();
271 #endif
272 
273 	/*
274 	 * The following things must be done before autoconfiguration.
275 	 */
276 	evcnt_init();		/* initialize event counters */
277 #if NRND > 0
278 	rnd_init();		/* initialize RNG */
279 #endif
280 	/* Initialize the sysctl subsystem. */
281 	sysctl_init();
282 
283 	/* Initialize process and pgrp structures. */
284 	procinit();
285 	lwpinit();
286 
287 	/* Initialize signal-related data structures. */
288 	signal_init();
289 
290 	/* Create process 0 (the swapper). */
291 	proc0_init();
292 
293 	/*
294 	 * Charge root for one process.
295 	 */
296 	(void)chgproccnt(0, 1);
297 
298 	rqinit();
299 
300 	/* Initialize the file systems. */
301 #ifdef NVNODE_IMPLICIT
302 	/*
303 	 * If maximum number of vnodes in namei vnode cache is not explicitly
304 	 * defined in kernel config, adjust the number such as we use roughly
305 	 * 1.0% of memory for vnode cache (but not less than NVNODE vnodes).
306 	 */
307 	usevnodes = (ptoa((unsigned)physmem) / 100) / sizeof(struct vnode);
308 	if (usevnodes > desiredvnodes)
309 		desiredvnodes = usevnodes;
310 #endif
311 	vfsinit();
312 
313 
314 #ifdef __HAVE_TIMECOUNTER
315 	inittimecounter();
316 	ntp_init();
317 #endif /* __HAVE_TIMECOUNTER */
318 
319 	/* Initialize kauth. */
320 	kauth_init();
321 
322 	/* Configure the system hardware.  This will enable interrupts. */
323 	configure();
324 
325 #if defined(__SSP__) || defined(__SSP_ALL__)
326 	{
327 #ifdef DIAGNOSTIC
328 		printf("Initializing SSP:");
329 #endif
330 		/*
331 		 * We initialize ssp here carefully:
332 		 *	1. after we got some entropy
333 		 *	2. without calling a function
334 		 */
335 		size_t i;
336 		long guard[__arraycount(__stack_chk_guard)];
337 
338 		arc4randbytes(guard, sizeof(guard));
339 		for (i = 0; i < __arraycount(guard); i++)
340 			__stack_chk_guard[i] = guard[i];
341 #ifdef DIAGNOSTIC
342 		for (i = 0; i < __arraycount(guard); i++)
343 			printf("%lx ", guard[i]);
344 		printf("\n");
345 #endif
346 	}
347 #endif
348 	ubc_init();		/* must be after autoconfig */
349 
350 	/* Lock the kernel on behalf of proc0. */
351 	KERNEL_PROC_LOCK(l);
352 
353 #ifdef SYSVSHM
354 	/* Initialize System V style shared memory. */
355 	shminit();
356 #endif
357 
358 #ifdef SYSVSEM
359 	/* Initialize System V style semaphores. */
360 	seminit();
361 #endif
362 
363 #ifdef SYSVMSG
364 	/* Initialize System V style message queues. */
365 	msginit();
366 #endif
367 
368 #ifdef P1003_1B_SEMAPHORE
369 	/* Initialize posix semaphores */
370 	ksem_init();
371 #endif
372 
373 	/* Initialize default security model. */
374 	secmodel_start();
375 
376 #ifdef FILEASSOC
377 	fileassoc_init();
378 #endif /* FILEASSOC */
379 
380 #if NVERIEXEC > 0
381 	  /*
382 	   * Initialise the fingerprint operations vectors before
383 	   * fingerprints can be loaded.
384 	   */
385 	veriexec_init_fp_ops();
386 #endif /* NVERIEXEC > 0 */
387 
388 	/* Attach pseudo-devices. */
389 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
390 		(*pdev->pdev_attach)(pdev->pdev_count);
391 
392 #ifdef	FAST_IPSEC
393 	/* Attach network crypto subsystem */
394 	ipsec_attach();
395 #endif
396 
397 	/*
398 	 * Initialize protocols.  Block reception of incoming packets
399 	 * until everything is ready.
400 	 */
401 	s = splnet();
402 	ifinit();
403 	domaininit();
404 	if_attachdomain();
405 	splx(s);
406 
407 #ifdef GPROF
408 	/* Initialize kernel profiling. */
409 	kmstartup();
410 #endif
411 
412 	/* Initialize system accouting. */
413 	acct_init();
414 
415 	/* Kick off timeout driven events by calling first time. */
416 	schedcpu(NULL);
417 
418 	/*
419 	 * Create process 1 (init(8)).  We do this now, as Unix has
420 	 * historically had init be process 1, and changing this would
421 	 * probably upset a lot of people.
422 	 *
423 	 * Note that process 1 won't immediately exec init(8), but will
424 	 * wait for us to inform it that the root file system has been
425 	 * mounted.
426 	 */
427 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
428 		panic("fork init");
429 
430 	/*
431 	 * Create any kernel threads who's creation was deferred because
432 	 * initproc had not yet been created.
433 	 */
434 	kthread_run_deferred_queue();
435 
436 	/*
437 	 * Now that device driver threads have been created, wait for
438 	 * them to finish any deferred autoconfiguration.  Note we don't
439 	 * need to lock this semaphore, since we haven't booted any
440 	 * secondary processors, yet.
441 	 */
442 	while (config_pending)
443 		(void) tsleep(&config_pending, PWAIT, "cfpend", 0);
444 
445 	/*
446 	 * Finalize configuration now that all real devices have been
447 	 * found.  This needs to be done before the root device is
448 	 * selected, since finalization may create the root device.
449 	 */
450 	config_finalize();
451 
452 	/*
453 	 * Now that autoconfiguration has completed, we can determine
454 	 * the root and dump devices.
455 	 */
456 	cpu_rootconf();
457 	cpu_dumpconf();
458 
459 	/* Mount the root file system. */
460 	do {
461 		domountroothook();
462 		if ((error = vfs_mountroot())) {
463 			printf("cannot mount root, error = %d\n", error);
464 			boothowto |= RB_ASKNAME;
465 			setroot(root_device,
466 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
467 		}
468 	} while (error != 0);
469 	mountroothook_destroy();
470 
471 	/*
472 	 * Initialise the time-of-day clock, passing the time recorded
473 	 * in the root filesystem (if any) for use by systems that
474 	 * don't have a non-volatile time-of-day device.
475 	 */
476 	inittodr(rootfstime);
477 
478 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
479 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
480 
481 	/*
482 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
483 	 * reference it.
484 	 */
485 	error = VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode);
486 	if (error)
487 		panic("cannot find root vnode, error=%d", error);
488 	cwdi0.cwdi_cdir = rootvnode;
489 	VREF(cwdi0.cwdi_cdir);
490 	VOP_UNLOCK(rootvnode, 0);
491 	cwdi0.cwdi_rdir = NULL;
492 
493 	/*
494 	 * Now that root is mounted, we can fixup initproc's CWD
495 	 * info.  All other processes are kthreads, which merely
496 	 * share proc0's CWD info.
497 	 */
498 	initproc->p_cwdi->cwdi_cdir = rootvnode;
499 	VREF(initproc->p_cwdi->cwdi_cdir);
500 	initproc->p_cwdi->cwdi_rdir = NULL;
501 
502 	/*
503 	 * Now can look at time, having had a chance to verify the time
504 	 * from the file system.  Reset p->p_rtime as it may have been
505 	 * munched in mi_switch() after the time got set.
506 	 */
507 	proclist_lock_read();
508 	s = splsched();
509 #ifdef __HAVE_TIMECOUNTER
510 	getmicrotime(&time);
511 #else
512 	mono_time = time;
513 #endif
514 	boottime = time;
515 	LIST_FOREACH(p, &allproc, p_list) {
516 		KASSERT((p->p_flag & P_MARKER) == 0);
517 		p->p_stats->p_start = time;
518 		LIST_FOREACH(l, &p->p_lwps, l_sibling) {
519 			if (l->l_cpu != NULL)
520 				l->l_cpu->ci_schedstate.spc_runtime = time;
521 		}
522 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
523 	}
524 	splx(s);
525 	proclist_unlock_read();
526 
527 	/* Create the pageout daemon kernel thread. */
528 	uvm_swap_init();
529 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
530 		panic("fork pagedaemon");
531 
532 	/* Create the filesystem syncer kernel thread. */
533 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
534 		panic("fork syncer");
535 
536 	/* Create the aiodone daemon kernel thread. */
537 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
538 	    "aiodoned"))
539 		panic("fork aiodoned");
540 
541 #if defined(MULTIPROCESSOR)
542 	/* Boot the secondary processors. */
543 	cpu_boot_secondary_processors();
544 #endif
545 
546 	/* Initialize exec structures */
547 	exec_init(1);
548 
549 	/*
550 	 * Okay, now we can let init(8) exec!  It's off to userland!
551 	 */
552 	start_init_exec = 1;
553 	wakeup(&start_init_exec);
554 
555 	/* The scheduler is an infinite loop. */
556 	uvm_scheduler();
557 	/* NOTREACHED */
558 }
559 
560 void
561 setrootfstime(time_t t)
562 {
563 	rootfstime = t;
564 }
565 
566 static void
567 check_console(struct lwp *l)
568 {
569 	struct nameidata nd;
570 	int error;
571 
572 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", l);
573 	error = namei(&nd);
574 	if (error == 0)
575 		vrele(nd.ni_vp);
576 	else if (error == ENOENT)
577 		printf("warning: no /dev/console\n");
578 	else
579 		printf("warning: lookup /dev/console: error %d\n", error);
580 }
581 
582 /*
583  * List of paths to try when searching for "init".
584  */
585 static const char *initpaths[] = {
586 	"/sbin/init",
587 	"/sbin/oinit",
588 	"/sbin/init.bak",
589 	NULL,
590 };
591 
592 /*
593  * Start the initial user process; try exec'ing each pathname in "initpaths".
594  * The program is invoked with one argument containing the boot flags.
595  */
596 static void
597 start_init(void *arg)
598 {
599 	struct lwp *l = arg;
600 	struct proc *p = l->l_proc;
601 	vaddr_t addr;
602 	struct sys_execve_args /* {
603 		syscallarg(const char *) path;
604 		syscallarg(char * const *) argp;
605 		syscallarg(char * const *) envp;
606 	} */ args;
607 	int options, i, error;
608 	register_t retval[2];
609 	char flags[4], *flagsp;
610 	const char *path, *slash;
611 	char *ucp, **uap, *arg0, *arg1 = NULL;
612 	char ipath[129];
613 	int ipx, len;
614 
615 	/*
616 	 * Now in process 1.
617 	 */
618 	strncpy(p->p_comm, "init", MAXCOMLEN);
619 
620 	/*
621 	 * Wait for main() to tell us that it's safe to exec.
622 	 */
623 	while (start_init_exec == 0)
624 		(void) tsleep(&start_init_exec, PWAIT, "initexec", 0);
625 
626 	/*
627 	 * This is not the right way to do this.  We really should
628 	 * hand-craft a descriptor onto /dev/console to hand to init,
629 	 * but that's a _lot_ more work, and the benefit from this easy
630 	 * hack makes up for the "good is the enemy of the best" effect.
631 	 */
632 	check_console(l);
633 
634 	/*
635 	 * Need just enough stack to hold the faked-up "execve()" arguments.
636 	 */
637 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
638 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
639                     NULL, UVM_UNKNOWN_OFFSET, 0,
640                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
641 		    UVM_ADV_NORMAL,
642                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
643 		panic("init: couldn't allocate argument space");
644 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
645 
646 	ipx = 0;
647 	while (1) {
648 		if (boothowto & RB_ASKNAME) {
649 			printf("init path");
650 			if (initpaths[ipx])
651 				printf(" (default %s)", initpaths[ipx]);
652 			printf(": ");
653 			len = cngetsn(ipath, sizeof(ipath)-1);
654 			if (len == 0) {
655 				if (initpaths[ipx])
656 					path = initpaths[ipx++];
657 				else
658 					continue;
659 			} else {
660 				ipath[len] = '\0';
661 				path = ipath;
662 			}
663 		} else {
664 			if ((path = initpaths[ipx++]) == NULL)
665 				break;
666 		}
667 
668 		ucp = (char *)USRSTACK;
669 
670 		/*
671 		 * Construct the boot flag argument.
672 		 */
673 		flagsp = flags;
674 		*flagsp++ = '-';
675 		options = 0;
676 
677 		if (boothowto & RB_SINGLE) {
678 			*flagsp++ = 's';
679 			options = 1;
680 		}
681 #ifdef notyet
682 		if (boothowto & RB_FASTBOOT) {
683 			*flagsp++ = 'f';
684 			options = 1;
685 		}
686 #endif
687 
688 		/*
689 		 * Move out the flags (arg 1), if necessary.
690 		 */
691 		if (options != 0) {
692 			*flagsp++ = '\0';
693 			i = flagsp - flags;
694 #ifdef DEBUG
695 			printf("init: copying out flags `%s' %d\n", flags, i);
696 #endif
697 			arg1 = STACK_ALLOC(ucp, i);
698 			ucp = STACK_MAX(arg1, i);
699 			(void)copyout((caddr_t)flags, arg1, i);
700 		}
701 
702 		/*
703 		 * Move out the file name (also arg 0).
704 		 */
705 		i = strlen(path) + 1;
706 #ifdef DEBUG
707 		printf("init: copying out path `%s' %d\n", path, i);
708 #else
709 		if (boothowto & RB_ASKNAME || path != initpaths[0])
710 			printf("init: trying %s\n", path);
711 #endif
712 		arg0 = STACK_ALLOC(ucp, i);
713 		ucp = STACK_MAX(arg0, i);
714 		(void)copyout(path, arg0, i);
715 
716 		/*
717 		 * Move out the arg pointers.
718 		 */
719 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
720 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
721 		SCARG(&args, path) = arg0;
722 		SCARG(&args, argp) = uap;
723 		SCARG(&args, envp) = NULL;
724 		slash = strrchr(path, '/');
725 		if (slash)
726 			(void)suword((caddr_t)uap++,
727 			    (long)arg0 + (slash + 1 - path));
728 		else
729 			(void)suword((caddr_t)uap++, (long)arg0);
730 		if (options != 0)
731 			(void)suword((caddr_t)uap++, (long)arg1);
732 		(void)suword((caddr_t)uap++, 0);	/* terminator */
733 
734 		/*
735 		 * Now try to exec the program.  If can't for any reason
736 		 * other than it doesn't exist, complain.
737 		 */
738 		error = sys_execve(l, &args, retval);
739 		if (error == 0 || error == EJUSTRETURN) {
740 			KERNEL_PROC_UNLOCK(l);
741 			return;
742 		}
743 		printf("exec %s: error %d\n", path, error);
744 	}
745 	printf("init: not found\n");
746 	panic("no init");
747 }
748