xref: /netbsd-src/sys/kern/init_main.c (revision c0179c282a5968435315a82f4128c61372c68fc3)
1 /*	$NetBSD: init_main.c,v 1.282 2006/11/22 02:02:51 elad 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 1.282 2006/11/22 02:02:51 elad 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 #include "opt_pax.h"
86 
87 #include "rnd.h"
88 #include "veriexec.h"
89 
90 #include <sys/param.h>
91 #include <sys/acct.h>
92 #include <sys/filedesc.h>
93 #include <sys/file.h>
94 #include <sys/errno.h>
95 #include <sys/callout.h>
96 #include <sys/kernel.h>
97 #include <sys/kcont.h>
98 #include <sys/kmem.h>
99 #include <sys/mount.h>
100 #include <sys/proc.h>
101 #include <sys/kthread.h>
102 #include <sys/resourcevar.h>
103 #include <sys/signalvar.h>
104 #include <sys/systm.h>
105 #include <sys/vnode.h>
106 #include <sys/tty.h>
107 #include <sys/conf.h>
108 #include <sys/disklabel.h>
109 #include <sys/buf.h>
110 #include <sys/device.h>
111 #include <sys/exec.h>
112 #include <sys/socketvar.h>
113 #include <sys/protosw.h>
114 #include <sys/reboot.h>
115 #include <sys/user.h>
116 #include <sys/sysctl.h>
117 #include <sys/event.h>
118 #include <sys/mbuf.h>
119 #ifdef FAST_IPSEC
120 #include <netipsec/ipsec.h>
121 #endif
122 #ifdef SYSVSHM
123 #include <sys/shm.h>
124 #endif
125 #ifdef SYSVSEM
126 #include <sys/sem.h>
127 #endif
128 #ifdef SYSVMSG
129 #include <sys/msg.h>
130 #endif
131 #ifdef P1003_1B_SEMAPHORE
132 #include <sys/ksem.h>
133 #endif
134 #include <sys/domain.h>
135 #include <sys/namei.h>
136 #if NRND > 0
137 #include <sys/rnd.h>
138 #endif
139 #ifndef PIPE_SOCKETPAIR
140 #include <sys/pipe.h>
141 #endif
142 #ifdef LKM
143 #include <sys/lkm.h>
144 #endif
145 #if NVERIEXEC > 0
146 #include <sys/verified_exec.h>
147 #endif /* NVERIEXEC > 0 */
148 #include <sys/kauth.h>
149 #include <net80211/ieee80211_netbsd.h>
150 
151 #include <sys/syscall.h>
152 #include <sys/sa.h>
153 #include <sys/syscallargs.h>
154 
155 #ifdef FILEASSOC
156 #include <sys/fileassoc.h>
157 #endif /* FILEASSOC */
158 
159 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD)
160 #include <sys/pax.h>
161 #endif /* PAX_MPROTECT || PAX_SEGVGUARD */
162 #include <ufs/ufs/quota.h>
163 
164 #include <miscfs/genfs/genfs.h>
165 #include <miscfs/syncfs/syncfs.h>
166 
167 #include <machine/cpu.h>
168 
169 #include <uvm/uvm.h>
170 
171 #include <dev/cons.h>
172 
173 #include <net/if.h>
174 #include <net/raw_cb.h>
175 
176 #include <secmodel/secmodel.h>
177 
178 extern struct proc proc0;
179 extern struct lwp lwp0;
180 extern struct cwdinfo cwdi0;
181 
182 #ifndef curlwp
183 struct	lwp *curlwp = &lwp0;
184 #endif
185 struct	proc *initproc;
186 
187 struct	vnode *rootvp, *swapdev_vp;
188 int	boothowto;
189 int	cold = 1;			/* still working on startup */
190 struct timeval boottime;	        /* time at system startup - will only follow settime deltas */
191 time_t	rootfstime;			/* recorded root fs time, if known */
192 
193 volatile int start_init_exec;		/* semaphore for start_init() */
194 
195 static void check_console(struct lwp *l);
196 static void start_init(void *);
197 void main(void);
198 
199 #if defined(__SSP__) || defined(__SSP_ALL__)
200 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
201 void __stack_chk_fail(void);
202 
203 void
204 __stack_chk_fail(void)
205 {
206 	panic("stack overflow detected; terminated");
207 }
208 #endif
209 
210 /*
211  * System startup; initialize the world, create process 0, mount root
212  * filesystem, and fork to create init and pagedaemon.  Most of the
213  * hard work is done in the lower-level initialization routines including
214  * startup(), which does memory initialization and autoconfiguration.
215  */
216 void
217 main(void)
218 {
219 #ifdef __HAVE_TIMECOUNTER
220 	struct timeval time;
221 #endif
222 	struct lwp *l;
223 	struct proc *p;
224 	struct pdevinit *pdev;
225 	int s, error;
226 	extern struct pdevinit pdevinit[];
227 	extern void schedcpu(void *);
228 #ifdef NVNODE_IMPLICIT
229 	int usevnodes;
230 #endif
231 
232 	/*
233 	 * Initialize the current LWP pointer (curlwp) before
234 	 * any possible traps/probes to simplify trap processing.
235 	 */
236 	l = &lwp0;
237 	curlwp = l;
238 	l->l_cpu = curcpu();
239 	l->l_proc = &proc0;
240 	l->l_lid = 1;
241 
242 	/*
243 	 * Attempt to find console and initialize
244 	 * in case of early panic or other messages.
245 	 */
246 	consinit();
247 
248 	KERNEL_LOCK_INIT();
249 
250 	uvm_init();
251 
252 	kmem_init();
253 
254 	/* Do machine-dependent initialization. */
255 	cpu_startup();
256 
257 	/* Initialize callouts. */
258 	callout_startup();
259 
260 	/* Initialize the buffer cache */
261 	bufinit();
262 
263 	/*
264 	 * Initialize mbuf's.  Do this now because we might attempt to
265 	 * allocate mbufs or mbuf clusters during autoconfiguration.
266 	 */
267 	mbinit();
268 
269 	/* Initialize sockets. */
270 	soinit();
271 
272 #ifdef KCONT
273 	/* Initialize kcont. */
274         kcont_init();
275 #endif
276 
277 	/*
278 	 * The following things must be done before autoconfiguration.
279 	 */
280 	evcnt_init();		/* initialize event counters */
281 #if NRND > 0
282 	rnd_init();		/* initialize RNG */
283 #endif
284 	/* Initialize the sysctl subsystem. */
285 	sysctl_init();
286 
287 	/* Initialize process and pgrp structures. */
288 	procinit();
289 	lwpinit();
290 
291 	/* Initialize signal-related data structures. */
292 	signal_init();
293 
294 	/* Create process 0 (the swapper). */
295 	proc0_init();
296 
297 	/*
298 	 * Charge root for one process.
299 	 */
300 	(void)chgproccnt(0, 1);
301 
302 	rqinit();
303 
304 	/* Initialize the file systems. */
305 #ifdef NVNODE_IMPLICIT
306 	/*
307 	 * If maximum number of vnodes in namei vnode cache is not explicitly
308 	 * defined in kernel config, adjust the number such as we use roughly
309 	 * 1.0% of memory for vnode cache (but not less than NVNODE vnodes).
310 	 */
311 	usevnodes = (ptoa((unsigned)physmem) / 100) / sizeof(struct vnode);
312 	if (usevnodes > desiredvnodes)
313 		desiredvnodes = usevnodes;
314 #endif
315 	vfsinit();
316 
317 
318 #ifdef __HAVE_TIMECOUNTER
319 	inittimecounter();
320 	ntp_init();
321 #endif /* __HAVE_TIMECOUNTER */
322 
323 	/* Initialize kauth. */
324 	kauth_init();
325 
326 	/* Configure the system hardware.  This will enable interrupts. */
327 	configure();
328 
329 #if defined(__SSP__) || defined(__SSP_ALL__)
330 	{
331 #ifdef DIAGNOSTIC
332 		printf("Initializing SSP:");
333 #endif
334 		/*
335 		 * We initialize ssp here carefully:
336 		 *	1. after we got some entropy
337 		 *	2. without calling a function
338 		 */
339 		size_t i;
340 		long guard[__arraycount(__stack_chk_guard)];
341 
342 		arc4randbytes(guard, sizeof(guard));
343 		for (i = 0; i < __arraycount(guard); i++)
344 			__stack_chk_guard[i] = guard[i];
345 #ifdef DIAGNOSTIC
346 		for (i = 0; i < __arraycount(guard); i++)
347 			printf("%lx ", guard[i]);
348 		printf("\n");
349 #endif
350 	}
351 #endif
352 	ubc_init();		/* must be after autoconfig */
353 
354 	/* Lock the kernel on behalf of proc0. */
355 	KERNEL_PROC_LOCK(l);
356 
357 #ifdef SYSVSHM
358 	/* Initialize System V style shared memory. */
359 	shminit();
360 #endif
361 
362 #ifdef SYSVSEM
363 	/* Initialize System V style semaphores. */
364 	seminit();
365 #endif
366 
367 #ifdef SYSVMSG
368 	/* Initialize System V style message queues. */
369 	msginit();
370 #endif
371 
372 #ifdef P1003_1B_SEMAPHORE
373 	/* Initialize posix semaphores */
374 	ksem_init();
375 #endif
376 
377 	/* Initialize default security model. */
378 	secmodel_start();
379 
380 #ifdef FILEASSOC
381 	fileassoc_init();
382 #endif /* FILEASSOC */
383 
384 #if NVERIEXEC > 0
385 	  /*
386 	   * Initialise the fingerprint operations vectors before
387 	   * fingerprints can be loaded.
388 	   */
389 	veriexec_init_fp_ops();
390 #endif /* NVERIEXEC > 0 */
391 
392 #if defined(PAX_MPROTECT) || defined(PAX_SEGVGUARD)
393 	pax_init();
394 #endif /* PAX_MPROTECT || PAX_SEGVGUARD */
395 
396 	/* Attach pseudo-devices. */
397 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
398 		(*pdev->pdev_attach)(pdev->pdev_count);
399 
400 #ifdef	FAST_IPSEC
401 	/* Attach network crypto subsystem */
402 	ipsec_attach();
403 #endif
404 
405 	/*
406 	 * Initialize protocols.  Block reception of incoming packets
407 	 * until everything is ready.
408 	 */
409 	s = splnet();
410 	ifinit();
411 	domaininit();
412 	if_attachdomain();
413 	splx(s);
414 
415 #ifdef GPROF
416 	/* Initialize kernel profiling. */
417 	kmstartup();
418 #endif
419 
420 	/* Initialize system accouting. */
421 	acct_init();
422 
423 	/* Kick off timeout driven events by calling first time. */
424 	schedcpu(NULL);
425 
426 	/*
427 	 * Create process 1 (init(8)).  We do this now, as Unix has
428 	 * historically had init be process 1, and changing this would
429 	 * probably upset a lot of people.
430 	 *
431 	 * Note that process 1 won't immediately exec init(8), but will
432 	 * wait for us to inform it that the root file system has been
433 	 * mounted.
434 	 */
435 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
436 		panic("fork init");
437 
438 	/*
439 	 * Create any kernel threads who's creation was deferred because
440 	 * initproc had not yet been created.
441 	 */
442 	kthread_run_deferred_queue();
443 
444 	/*
445 	 * Now that device driver threads have been created, wait for
446 	 * them to finish any deferred autoconfiguration.  Note we don't
447 	 * need to lock this semaphore, since we haven't booted any
448 	 * secondary processors, yet.
449 	 */
450 	while (config_pending)
451 		(void) tsleep(&config_pending, PWAIT, "cfpend", 0);
452 
453 	/*
454 	 * Finalize configuration now that all real devices have been
455 	 * found.  This needs to be done before the root device is
456 	 * selected, since finalization may create the root device.
457 	 */
458 	config_finalize();
459 
460 	/*
461 	 * Now that autoconfiguration has completed, we can determine
462 	 * the root and dump devices.
463 	 */
464 	cpu_rootconf();
465 	cpu_dumpconf();
466 
467 	/* Mount the root file system. */
468 	do {
469 		domountroothook();
470 		if ((error = vfs_mountroot())) {
471 			printf("cannot mount root, error = %d\n", error);
472 			boothowto |= RB_ASKNAME;
473 			setroot(root_device,
474 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
475 		}
476 	} while (error != 0);
477 	mountroothook_destroy();
478 
479 	/*
480 	 * Initialise the time-of-day clock, passing the time recorded
481 	 * in the root filesystem (if any) for use by systems that
482 	 * don't have a non-volatile time-of-day device.
483 	 */
484 	inittodr(rootfstime);
485 
486 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
487 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
488 
489 	/*
490 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
491 	 * reference it.
492 	 */
493 	error = VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode);
494 	if (error)
495 		panic("cannot find root vnode, error=%d", error);
496 	cwdi0.cwdi_cdir = rootvnode;
497 	VREF(cwdi0.cwdi_cdir);
498 	VOP_UNLOCK(rootvnode, 0);
499 	cwdi0.cwdi_rdir = NULL;
500 
501 	/*
502 	 * Now that root is mounted, we can fixup initproc's CWD
503 	 * info.  All other processes are kthreads, which merely
504 	 * share proc0's CWD info.
505 	 */
506 	initproc->p_cwdi->cwdi_cdir = rootvnode;
507 	VREF(initproc->p_cwdi->cwdi_cdir);
508 	initproc->p_cwdi->cwdi_rdir = NULL;
509 
510 	/*
511 	 * Now can look at time, having had a chance to verify the time
512 	 * from the file system.  Reset p->p_rtime as it may have been
513 	 * munched in mi_switch() after the time got set.
514 	 */
515 	proclist_lock_read();
516 	s = splsched();
517 #ifdef __HAVE_TIMECOUNTER
518 	getmicrotime(&time);
519 #else
520 	mono_time = time;
521 #endif
522 	boottime = time;
523 	LIST_FOREACH(p, &allproc, p_list) {
524 		KASSERT((p->p_flag & P_MARKER) == 0);
525 		p->p_stats->p_start = time;
526 		LIST_FOREACH(l, &p->p_lwps, l_sibling) {
527 			if (l->l_cpu != NULL)
528 				l->l_cpu->ci_schedstate.spc_runtime = time;
529 		}
530 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
531 	}
532 	splx(s);
533 	proclist_unlock_read();
534 
535 	/* Create the pageout daemon kernel thread. */
536 	uvm_swap_init();
537 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
538 		panic("fork pagedaemon");
539 
540 	/* Create the filesystem syncer kernel thread. */
541 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
542 		panic("fork syncer");
543 
544 	/* Create the aiodone daemon kernel thread. */
545 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
546 	    "aiodoned"))
547 		panic("fork aiodoned");
548 
549 #if defined(MULTIPROCESSOR)
550 	/* Boot the secondary processors. */
551 	cpu_boot_secondary_processors();
552 #endif
553 
554 	/* Initialize exec structures */
555 	exec_init(1);
556 
557 	/*
558 	 * Okay, now we can let init(8) exec!  It's off to userland!
559 	 */
560 	start_init_exec = 1;
561 	wakeup(&start_init_exec);
562 
563 	/* The scheduler is an infinite loop. */
564 	uvm_scheduler();
565 	/* NOTREACHED */
566 }
567 
568 void
569 setrootfstime(time_t t)
570 {
571 	rootfstime = t;
572 }
573 
574 static void
575 check_console(struct lwp *l)
576 {
577 	struct nameidata nd;
578 	int error;
579 
580 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", l);
581 	error = namei(&nd);
582 	if (error == 0)
583 		vrele(nd.ni_vp);
584 	else if (error == ENOENT)
585 		printf("warning: no /dev/console\n");
586 	else
587 		printf("warning: lookup /dev/console: error %d\n", error);
588 }
589 
590 /*
591  * List of paths to try when searching for "init".
592  */
593 static const char *initpaths[] = {
594 	"/sbin/init",
595 	"/sbin/oinit",
596 	"/sbin/init.bak",
597 	NULL,
598 };
599 
600 /*
601  * Start the initial user process; try exec'ing each pathname in "initpaths".
602  * The program is invoked with one argument containing the boot flags.
603  */
604 static void
605 start_init(void *arg)
606 {
607 	struct lwp *l = arg;
608 	struct proc *p = l->l_proc;
609 	vaddr_t addr;
610 	struct sys_execve_args /* {
611 		syscallarg(const char *) path;
612 		syscallarg(char * const *) argp;
613 		syscallarg(char * const *) envp;
614 	} */ args;
615 	int options, i, error;
616 	register_t retval[2];
617 	char flags[4], *flagsp;
618 	const char *path, *slash;
619 	char *ucp, **uap, *arg0, *arg1 = NULL;
620 	char ipath[129];
621 	int ipx, len;
622 
623 	/*
624 	 * Now in process 1.
625 	 */
626 	strncpy(p->p_comm, "init", MAXCOMLEN);
627 
628 	/*
629 	 * Wait for main() to tell us that it's safe to exec.
630 	 */
631 	while (start_init_exec == 0)
632 		(void) tsleep(&start_init_exec, PWAIT, "initexec", 0);
633 
634 	/*
635 	 * This is not the right way to do this.  We really should
636 	 * hand-craft a descriptor onto /dev/console to hand to init,
637 	 * but that's a _lot_ more work, and the benefit from this easy
638 	 * hack makes up for the "good is the enemy of the best" effect.
639 	 */
640 	check_console(l);
641 
642 	/*
643 	 * Need just enough stack to hold the faked-up "execve()" arguments.
644 	 */
645 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
646 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
647                     NULL, UVM_UNKNOWN_OFFSET, 0,
648                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
649 		    UVM_ADV_NORMAL,
650                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
651 		panic("init: couldn't allocate argument space");
652 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
653 
654 	ipx = 0;
655 	while (1) {
656 		if (boothowto & RB_ASKNAME) {
657 			printf("init path");
658 			if (initpaths[ipx])
659 				printf(" (default %s)", initpaths[ipx]);
660 			printf(": ");
661 			len = cngetsn(ipath, sizeof(ipath)-1);
662 			if (len == 0) {
663 				if (initpaths[ipx])
664 					path = initpaths[ipx++];
665 				else
666 					continue;
667 			} else {
668 				ipath[len] = '\0';
669 				path = ipath;
670 			}
671 		} else {
672 			if ((path = initpaths[ipx++]) == NULL)
673 				break;
674 		}
675 
676 		ucp = (char *)USRSTACK;
677 
678 		/*
679 		 * Construct the boot flag argument.
680 		 */
681 		flagsp = flags;
682 		*flagsp++ = '-';
683 		options = 0;
684 
685 		if (boothowto & RB_SINGLE) {
686 			*flagsp++ = 's';
687 			options = 1;
688 		}
689 #ifdef notyet
690 		if (boothowto & RB_FASTBOOT) {
691 			*flagsp++ = 'f';
692 			options = 1;
693 		}
694 #endif
695 
696 		/*
697 		 * Move out the flags (arg 1), if necessary.
698 		 */
699 		if (options != 0) {
700 			*flagsp++ = '\0';
701 			i = flagsp - flags;
702 #ifdef DEBUG
703 			printf("init: copying out flags `%s' %d\n", flags, i);
704 #endif
705 			arg1 = STACK_ALLOC(ucp, i);
706 			ucp = STACK_MAX(arg1, i);
707 			(void)copyout((caddr_t)flags, arg1, i);
708 		}
709 
710 		/*
711 		 * Move out the file name (also arg 0).
712 		 */
713 		i = strlen(path) + 1;
714 #ifdef DEBUG
715 		printf("init: copying out path `%s' %d\n", path, i);
716 #else
717 		if (boothowto & RB_ASKNAME || path != initpaths[0])
718 			printf("init: trying %s\n", path);
719 #endif
720 		arg0 = STACK_ALLOC(ucp, i);
721 		ucp = STACK_MAX(arg0, i);
722 		(void)copyout(path, arg0, i);
723 
724 		/*
725 		 * Move out the arg pointers.
726 		 */
727 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
728 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
729 		SCARG(&args, path) = arg0;
730 		SCARG(&args, argp) = uap;
731 		SCARG(&args, envp) = NULL;
732 		slash = strrchr(path, '/');
733 		if (slash)
734 			(void)suword((caddr_t)uap++,
735 			    (long)arg0 + (slash + 1 - path));
736 		else
737 			(void)suword((caddr_t)uap++, (long)arg0);
738 		if (options != 0)
739 			(void)suword((caddr_t)uap++, (long)arg1);
740 		(void)suword((caddr_t)uap++, 0);	/* terminator */
741 
742 		/*
743 		 * Now try to exec the program.  If can't for any reason
744 		 * other than it doesn't exist, complain.
745 		 */
746 		error = sys_execve(l, &args, retval);
747 		if (error == 0 || error == EJUSTRETURN) {
748 			KERNEL_PROC_UNLOCK(l);
749 			return;
750 		}
751 		printf("exec %s: error %d\n", path, error);
752 	}
753 	printf("init: not found\n");
754 	panic("no init");
755 }
756