xref: /openbsd-src/sys/kern/init_main.c (revision 94c38e45691bfc7020490efddf82c55c25ceeb99)
1 /*	$OpenBSD: init_main.c,v 1.322 2023/08/29 16:19:34 claudio Exp $	*/
2 /*	$NetBSD: init_main.c,v 1.84.4.1 1996/06/02 09:08:06 mrg Exp $	*/
3 
4 /*
5  * Copyright (c) 1995 Christopher G. Demetriou.  All rights reserved.
6  * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  * (c) UNIX System Laboratories, Inc.
9  * All or some portions of this file are derived from material licensed
10  * to the University of California by American Telephone and Telegraph
11  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
12  * the permission of UNIX System Laboratories, Inc.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)init_main.c	8.9 (Berkeley) 1/21/94
39  */
40 
41 #include <sys/param.h>
42 #include <sys/filedesc.h>
43 #include <sys/errno.h>
44 #include <sys/kthread.h>
45 #include <sys/mount.h>
46 #include <sys/proc.h>
47 #include <sys/resourcevar.h>
48 #include <sys/signalvar.h>
49 #include <sys/systm.h>
50 #include <sys/clockintr.h>
51 #include <sys/namei.h>
52 #include <sys/vnode.h>
53 #include <sys/tty.h>
54 #include <sys/buf.h>
55 #include <sys/device.h>
56 #include <sys/socketvar.h>
57 #include <sys/lockf.h>
58 #include <sys/reboot.h>
59 #ifdef SYSVSHM
60 #include <sys/shm.h>
61 #endif
62 #ifdef SYSVSEM
63 #include <sys/sem.h>
64 #endif
65 #ifdef SYSVMSG
66 #include <sys/msg.h>
67 #endif
68 #include <sys/domain.h>
69 #include <sys/event.h>
70 #include <sys/msgbuf.h>
71 #include <sys/mbuf.h>
72 #include <sys/pipe.h>
73 #include <sys/witness.h>
74 #include <sys/smr.h>
75 #include <sys/evcount.h>
76 
77 #include <sys/syscallargs.h>
78 
79 #include <uvm/uvm_extern.h>
80 
81 #include <net/if.h>
82 #include <net/rtable.h>
83 
84 #if defined(CRYPTO)
85 #include <crypto/cryptodev.h>
86 #include <crypto/cryptosoft.h>
87 #endif
88 
89 #if defined(KUBSAN)
90 extern void kubsan_init(void);
91 #endif
92 
93 #if defined(NFSSERVER) || defined(NFSCLIENT)
94 extern void nfs_init(void);
95 #endif
96 
97 #include "stoeplitz.h"
98 #if NSTOEPLITZ > 0
99 extern void stoeplitz_init(void);
100 #endif
101 
102 #include "mpath.h"
103 #include "vscsi.h"
104 #include "softraid.h"
105 
106 const char	copyright[] =
107 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
108 "\tThe Regents of the University of California.  All rights reserved.\n"
109 "Copyright (c) 1995-2023 OpenBSD. All rights reserved.  https://www.OpenBSD.org\n";
110 
111 /* Components of the first process -- never freed. */
112 struct	session session0;
113 struct	pgrp pgrp0;
114 struct	proc proc0;
115 struct	process process0;
116 struct	plimit limit0;
117 struct	vmspace vmspace0;
118 struct	sigacts sigacts0;
119 struct	process *initprocess;
120 struct	proc *reaperproc;
121 
122 extern	struct user *proc0paddr;
123 
124 struct	vnode *rootvp, *swapdev_vp;
125 int	boothowto;
126 int	db_active = 0;
127 int	ncpus =  1;
128 int	ncpusfound = 1;			/* number of cpus we find */
129 volatile int start_init_exec;		/* semaphore for start_init() */
130 
131 #if !defined(NO_PROPOLICE)
132 long	__guard_local __attribute__((section(".openbsd.randomdata")));
133 #endif
134 
135 /* XXX return int so gcc -Werror won't complain */
136 int	main(void *);
137 void	check_console(struct proc *);
138 void	start_init(void *);
139 void	db_ctf_init(void);
140 void	prof_init(void);
141 void	init_exec(void);
142 void	futex_init(void);
143 void	taskq_init(void);
144 void	timeout_proc_init(void);
145 void	pool_gc_pages(void *);
146 void	percpu_init(void);
147 
148 #ifdef DIAGNOSTIC
149 int pdevinit_done = 0;
150 #endif
151 
152 /*
153  * System startup; initialize the world, create process 0, mount root
154  * filesystem, and fork to create init and pagedaemon.  Most of the
155  * hard work is done in the lower-level initialization routines including
156  * startup(), which does memory initialization and autoconfiguration.
157  */
158 /* XXX return int, so gcc -Werror won't complain */
159 int
160 main(void *framep)
161 {
162 	struct proc *p;
163 	struct process *pr;
164 	struct pdevinit *pdev;
165 	extern struct pdevinit pdevinit[];
166 	extern void disk_init(void);
167 
168 	/*
169 	 * Initialize the current process pointer (curproc) before
170 	 * any possible traps/probes to simplify trap processing.
171 	 */
172 	curproc = p = &proc0;
173 	p->p_cpu = curcpu();
174 
175 	/*
176 	 * Initialize timeouts.
177 	 */
178 	timeout_startup();
179 
180 	/*
181 	 * Attempt to find console and initialize
182 	 * in case of early panic or other messages.
183 	 */
184 	config_init();		/* init autoconfiguration data structures */
185 	consinit();
186 
187 	printf("%s\n", copyright);
188 
189 #ifdef KUBSAN
190 	/* Initialize kubsan. */
191 	kubsan_init();
192 #endif
193 
194 	WITNESS_INITIALIZE();
195 
196 	KERNEL_LOCK_INIT();
197 	SCHED_LOCK_INIT();
198 
199 	rw_obj_init();
200 	uvm_init();
201 	disk_init();		/* must come before autoconfiguration */
202 	tty_init();		/* initialise tty's */
203 	cpu_startup();
204 
205 	random_start(boothowto & RB_GOODRANDOM);	/* Start the flow */
206 
207 	/*
208 	 * Initialize mbuf's.  Do this now because we might attempt to
209 	 * allocate mbufs or mbuf clusters during autoconfiguration.
210 	 */
211 	mbinit();
212 
213 #if NSTOEPLITZ > 0
214 	stoeplitz_init();
215 #endif
216 
217 	/* Initialize sockets. */
218 	soinit();
219 
220 	/* Initialize SRP subsystem. */
221 	srp_startup();
222 
223 	/* Initialize SMR subsystem. */
224 	smr_startup();
225 
226 	/*
227 	 * Initialize process and pgrp structures.
228 	 */
229 	procinit();
230 
231 	/* Initialize file locking. */
232 	lf_init();
233 
234 	/*
235 	 * Initialize filedescriptors.
236 	 */
237 	filedesc_init();
238 
239 	/*
240 	 * Initialize pipes.
241 	 */
242 	pipe_init();
243 
244 	/*
245 	 * Initialize kqueues.
246 	 */
247 	kqueue_init();
248 
249 	/*
250 	 * Initialize futexes.
251 	 */
252 	futex_init();
253 
254 	/* Create credentials. */
255 	p->p_ucred = crget();
256 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
257 
258 	/*
259 	 * Create process 0 (the swapper).
260 	 */
261 	pr = &process0;
262 	process_initialize(pr, p);
263 
264 	LIST_INSERT_HEAD(&allprocess, pr, ps_list);
265 	LIST_INSERT_HEAD(PIDHASH(0), pr, ps_hash);
266 	atomic_setbits_int(&pr->ps_flags, PS_SYSTEM);
267 
268 	/* Set the default routing table/domain. */
269 	process0.ps_rtableid = 0;
270 
271 	LIST_INSERT_HEAD(&allproc, p, p_list);
272 	pr->ps_pgrp = &pgrp0;
273 	LIST_INSERT_HEAD(TIDHASH(0), p, p_hash);
274 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
275 	LIST_INIT(&pgrp0.pg_members);
276 	LIST_INSERT_HEAD(&pgrp0.pg_members, pr, ps_pglist);
277 
278 	pgrp0.pg_session = &session0;
279 	session0.s_count = 1;
280 	session0.s_leader = pr;
281 
282 	atomic_setbits_int(&p->p_flag, P_SYSTEM);
283 	p->p_stat = SONPROC;
284 	pr->ps_nice = NZERO;
285 	strlcpy(pr->ps_comm, "swapper", sizeof(pr->ps_comm));
286 
287 	/* Init timeouts. */
288 	timeout_set(&p->p_sleep_to, endtsleep, p);
289 
290 	/* Initialize signal state for process 0. */
291 	signal_init();
292 	siginit(&sigacts0);
293 	pr->ps_sigacts = &sigacts0;
294 
295 	/* Create the file descriptor table. */
296 	p->p_fd = pr->ps_fd = fdinit();
297 
298 	/* Create the limits structures. */
299 	lim_startup(&limit0);
300 	pr->ps_limit = &limit0;
301 
302 	/* Allocate a prototype map so we have something to fork. */
303 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
304 	    trunc_page(VM_MAX_ADDRESS), TRUE, TRUE);
305 	p->p_vmspace = pr->ps_vmspace = &vmspace0;
306 
307 	p->p_addr = proc0paddr;				/* XXX */
308 
309 	/*
310 	 * Charge root for one process.
311 	 */
312 	(void)chgproccnt(0, 1);
313 
314 	/* Initialize run queues */
315 	sched_init_runqueues();
316 	sleep_queue_init();
317 	clockqueue_init(&curcpu()->ci_queue);
318 	sched_init_cpu(curcpu());
319 	p->p_cpu->ci_randseed = (arc4random() & 0x7fffffff) + 1;
320 
321 	/* Initialize timeouts in process context. */
322 	timeout_proc_init();
323 
324 	/* Initialize task queues */
325 	taskq_init();
326 
327 	/* Initialize the interface/address trees */
328 	ifinit();
329 
330 	/* Lock the kernel on behalf of proc0. */
331 	KERNEL_LOCK();
332 
333 #if NMPATH > 0
334 	/* Attach mpath before hardware */
335 	config_rootfound("mpath", NULL);
336 #endif
337 
338 	/* Configure the devices */
339 	cpu_configure();
340 
341 	/* Configure virtual memory system, set vm rlimits. */
342 	uvm_init_limits(&limit0);
343 
344 	/* Per CPU memory allocation */
345 	percpu_init();
346 
347 	/* Initialize the file systems. */
348 #if defined(NFSSERVER) || defined(NFSCLIENT)
349 	nfs_init();			/* initialize server/shared data */
350 #endif
351 	vfsinit();
352 
353 	/* Start real time and statistics clocks. */
354 	initclocks();
355 
356 #ifdef SYSVSHM
357 	/* Initialize System V style shared memory. */
358 	shminit();
359 #endif
360 
361 #ifdef SYSVSEM
362 	/* Initialize System V style semaphores. */
363 	seminit();
364 #endif
365 
366 #ifdef SYSVMSG
367 	/* Initialize System V style message queues. */
368 	msginit();
369 #endif
370 
371 	/* Create default routing table before attaching lo0. */
372 	rtable_init();
373 
374 	/* Attach pseudo-devices. */
375 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
376 		if (pdev->pdev_count > 0)
377 			(*pdev->pdev_attach)(pdev->pdev_count);
378 #ifdef DIAGNOSTIC
379 	pdevinit_done = 1;
380 #endif
381 
382 #ifdef CRYPTO
383 	crypto_init();
384 	swcr_init();
385 #endif /* CRYPTO */
386 
387 	/*
388 	 * Initialize protocols.
389 	 */
390 	domaininit();
391 
392 	initconsbuf();
393 
394 #if defined(GPROF) || defined(DDBPROF)
395 	/* Initialize kernel profiling. */
396 	prof_init();
397 #endif
398 
399 	/* Enable per-CPU data. */
400 	mbcpuinit();
401 	kqueue_init_percpu();
402 	uvm_init_percpu();
403 	evcount_init_percpu();
404 
405 	/* init exec */
406 	init_exec();
407 
408 	/* Start the scheduler */
409 	scheduler_start();
410 
411 	/*
412 	 * Create process 1 (init(8)).  We do this now, as Unix has
413 	 * historically had init be process 1, and changing this would
414 	 * probably upset a lot of people.
415 	 *
416 	 * Note that process 1 won't immediately exec init(8), but will
417 	 * wait for us to inform it that the root file system has been
418 	 * mounted.
419 	 */
420 	{
421 		struct proc *initproc;
422 
423 		if (fork1(p, FORK_FORK, start_init, NULL, NULL, &initproc))
424 			panic("fork init");
425 		initprocess = initproc->p_p;
426 	}
427 
428 	/*
429 	 * Create any kernel threads whose creation was deferred because
430 	 * initprocess had not yet been created.
431 	 */
432 	kthread_run_deferred_queue();
433 
434 	/*
435 	 * Now that device driver threads have been created, wait for
436 	 * them to finish any deferred autoconfiguration.  Note we don't
437 	 * need to lock this semaphore, since we haven't booted any
438 	 * secondary processors, yet.
439 	 */
440 	while (config_pending)
441 		tsleep_nsec(&config_pending, PWAIT, "cfpend", INFSLP);
442 
443 	dostartuphooks();
444 
445 #if NVSCSI > 0
446 	config_rootfound("vscsi", NULL);
447 #endif
448 #if NSOFTRAID > 0
449 	config_rootfound("softraid", NULL);
450 #endif
451 
452 	/* Configure root/swap devices */
453 	diskconf();
454 
455 #ifdef DDB
456 	/* Make debug symbols available in ddb. */
457 	db_ctf_init();
458 #endif
459 
460 	if (mountroot == NULL || ((*mountroot)() != 0))
461 		panic("cannot mount root");
462 
463 	TAILQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
464 
465 	/* Get the vnode for '/'.  Set p->p_fd->fd_cdir to reference it. */
466 	if (VFS_ROOT(TAILQ_FIRST(&mountlist), &rootvnode))
467 		panic("cannot find root vnode");
468 	p->p_fd->fd_cdir = rootvnode;
469 	vref(p->p_fd->fd_cdir);
470 	VOP_UNLOCK(rootvnode);
471 	p->p_fd->fd_rdir = NULL;
472 
473 	/*
474 	 * Now that root is mounted, we can fixup initprocess's CWD
475 	 * info.  All other processes are kthreads, which merely
476 	 * share proc0's CWD info.
477 	 */
478 	initprocess->ps_fd->fd_cdir = rootvnode;
479 	vref(initprocess->ps_fd->fd_cdir);
480 	initprocess->ps_fd->fd_rdir = NULL;
481 
482 	/*
483 	 * Now can look at time, having had a chance to verify the time
484 	 * from the file system.
485 	 */
486 	LIST_FOREACH(pr, &allprocess, ps_list) {
487 		nanouptime(&pr->ps_start);
488 	}
489 	nanouptime(&curcpu()->ci_schedstate.spc_runtime);
490 
491 	uvm_swap_init();
492 
493 	/* Create the pageout daemon kernel thread. */
494 	if (kthread_create(uvm_pageout, NULL, NULL, "pagedaemon"))
495 		panic("fork pagedaemon");
496 
497 	/* Create the reaper daemon kernel thread. */
498 	if (kthread_create(reaper, NULL, &reaperproc, "reaper"))
499 		panic("fork reaper");
500 
501 	/* Create the cleaner daemon kernel thread. */
502 	if (kthread_create(buf_daemon, NULL, &cleanerproc, "cleaner"))
503 		panic("fork cleaner");
504 
505 	/* Create the update daemon kernel thread. */
506 	if (kthread_create(syncer_thread, NULL, &syncerproc, "update"))
507 		panic("fork update");
508 
509 	/* Create the aiodone daemon kernel thread. */
510 	if (kthread_create(uvm_aiodone_daemon, NULL, NULL, "aiodoned"))
511 		panic("fork aiodoned");
512 
513 #if !defined(__hppa__)
514 	/* Create the page zeroing kernel thread. */
515 	if (kthread_create(uvm_pagezero_thread, NULL, NULL, "zerothread"))
516 		panic("fork zerothread");
517 #endif
518 
519 #if defined(MULTIPROCESSOR)
520 	/* Boot the secondary processors. */
521 	cpu_boot_secondary_processors();
522 #endif
523 
524 	/* Now that all CPUs partake in scheduling, start SMR thread. */
525 	smr_startup_thread();
526 
527 	config_process_deferred_mountroot();
528 
529 	/*
530 	 * Okay, now we can let init(8) exec!  It's off to userland!
531 	 */
532 	start_init_exec = 1;
533 	wakeup((void *)&start_init_exec);
534 
535 	/*
536 	 * Start the idle pool page garbage collector
537 	 */
538 #if !(defined(__m88k__) && defined(MULTIPROCESSOR))	/* XXX */
539 	pool_gc_pages(NULL);
540 #endif
541 
542 	start_periodic_resettodr();
543 
544         /*
545          * proc0: nothing to do, back to sleep
546          */
547         while (1)
548                 tsleep_nsec(&proc0, PVM, "scheduler", INFSLP);
549 	/* NOTREACHED */
550 }
551 
552 /*
553  * List of paths to try when searching for "init".
554  */
555 static char *initpaths[] = {
556 	"/sbin/init",
557 	"/sbin/oinit",
558 	"/sbin/init.bak",
559 	NULL,
560 };
561 
562 void
563 check_console(struct proc *p)
564 {
565 	struct nameidata nd;
566 	int error;
567 
568 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
569 	error = namei(&nd);
570 	if (error) {
571 		if (error == ENOENT)
572 			printf("warning: /dev/console does not exist\n");
573 		else
574 			printf("warning: /dev/console error %d\n", error);
575 	} else
576 		vrele(nd.ni_vp);
577 }
578 
579 /*
580  * Start the initial user process; try exec'ing each pathname in "initpaths".
581  * The program is invoked with one argument containing the boot flags.
582  */
583 void
584 start_init(void *arg)
585 {
586 	struct proc *p = arg;
587 	vaddr_t addr;
588 	struct sys_execve_args /* {
589 		syscallarg(const char *) path;
590 		syscallarg(char *const *) argp;
591 		syscallarg(char *const *) envp;
592 	} */ args;
593 	int options, error;
594 	long i;
595 	register_t retval[2];
596 	char flags[4], *flagsp;
597 	char **pathp, *path, *ucp, **uap, *arg0, *arg1 = NULL;
598 
599 	/*
600 	 * Now in process 1.
601 	 */
602 
603 	/*
604 	 * Wait for main() to tell us that it's safe to exec.
605 	 */
606 	while (start_init_exec == 0)
607 		tsleep_nsec(&start_init_exec, PWAIT, "initexec", INFSLP);
608 
609 	check_console(p);
610 
611 	/* process 0 ignores SIGCHLD, but we can't */
612 	p->p_p->ps_sigacts->ps_sigflags = 0;
613 
614 	/*
615 	 * Need just enough stack to hold the faked-up "execve()" arguments.
616 	 */
617 #ifdef MACHINE_STACK_GROWS_UP
618 	addr = USRSTACK;
619 #else
620 	addr = USRSTACK - PAGE_SIZE;
621 #endif
622 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
623 	p->p_vmspace->vm_minsaddr = (caddr_t)(addr + PAGE_SIZE);
624 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
625 	    NULL, UVM_UNKNOWN_OFFSET, 0,
626 	    UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_MASK, MAP_INHERIT_COPY,
627 	    MADV_NORMAL,
628 	    UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW|UVM_FLAG_STACK|UVM_FLAG_SYSCALL)))
629 		panic("init: couldn't allocate argument space");
630 
631 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
632 #ifdef MACHINE_STACK_GROWS_UP
633 		ucp = (char *)addr;
634 #else
635 		ucp = (char *)(addr + PAGE_SIZE);
636 #endif
637 		/*
638 		 * Construct the boot flag argument.
639 		 */
640 		flagsp = flags;
641 		*flagsp++ = '-';
642 		options = 0;
643 
644 		if (boothowto & RB_SINGLE) {
645 			*flagsp++ = 's';
646 			options = 1;
647 		}
648 #ifdef notyet
649 		if (boothowto & RB_FASTBOOT) {
650 			*flagsp++ = 'f';
651 			options = 1;
652 		}
653 #endif
654 
655 		/*
656 		 * Move out the flags (arg 1), if necessary.
657 		 */
658 		if (options != 0) {
659 			*flagsp++ = '\0';
660 			i = flagsp - flags;
661 #ifdef DEBUG
662 			printf("init: copying out flags `%s' %ld\n", flags, i);
663 #endif
664 #ifdef MACHINE_STACK_GROWS_UP
665 			arg1 = ucp;
666 			(void)copyout((caddr_t)flags, (caddr_t)ucp, i);
667 			ucp += i;
668 #else
669 			(void)copyout((caddr_t)flags, (caddr_t)(ucp -= i), i);
670 			arg1 = ucp;
671 #endif
672 		}
673 
674 		/*
675 		 * Move out the file name (also arg 0).
676 		 */
677 		i = strlen(path) + 1;
678 #ifdef DEBUG
679 		printf("init: copying out path `%s' %ld\n", path, i);
680 #endif
681 #ifdef MACHINE_STACK_GROWS_UP
682 		arg0 = ucp;
683 		(void)copyout((caddr_t)path, (caddr_t)ucp, i);
684 		ucp += i;
685 		ucp = (caddr_t)ALIGN((u_long)ucp);
686 		uap = (char **)ucp + 3;
687 #else
688 		(void)copyout((caddr_t)path, (caddr_t)(ucp -= i), i);
689 		arg0 = ucp;
690 		uap = (char **)((u_long)ucp & ~ALIGNBYTES);
691 #endif
692 
693 		/*
694 		 * Move out the arg pointers.
695 		 */
696 		i = 0;
697 		copyout(&i, (caddr_t)--uap, sizeof(register_t)); /* terminator */
698 		if (options != 0)
699 			copyout(&arg1, (caddr_t)--uap, sizeof(register_t));
700 		copyout(&arg0, (caddr_t)--uap, sizeof(register_t));
701 
702 		/*
703 		 * Point at the arguments.
704 		 */
705 		SCARG(&args, path) = arg0;
706 		SCARG(&args, argp) = uap;
707 		SCARG(&args, envp) = NULL;
708 
709 		/*
710 		 * Now try to exec the program.  If can't for any reason
711 		 * other than it doesn't exist, complain.
712 		 */
713 		if ((error = sys_execve(p, &args, retval)) == EJUSTRETURN) {
714 			KERNEL_UNLOCK();
715 			return;
716 		}
717 		if (error != ENOENT)
718 			printf("exec %s: error %d\n", path, error);
719 	}
720 	printf("init: not found\n");
721 	panic("no init");
722 }
723