xref: /netbsd-src/sys/kern/init_main.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: init_main.c,v 1.261 2005/12/24 19:12:23 perry 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 1.261 2005/12/24 19:12:23 perry Exp $");
75 
76 #include "opt_ipsec.h"
77 #include "opt_sysv.h"
78 #include "opt_maxuprc.h"
79 #include "opt_multiprocessor.h"
80 #include "opt_pipe.h"
81 #include "opt_syscall_debug.h"
82 #include "opt_systrace.h"
83 #include "opt_posix.h"
84 #include "opt_kcont.h"
85 #include "opt_rootfs_magiclinks.h"
86 #include "opt_verified_exec.h"
87 
88 #include "rnd.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/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 #ifdef SYSTRACE
134 #include <sys/systrace.h>
135 #endif
136 #include <sys/domain.h>
137 #include <sys/namei.h>
138 #if NRND > 0
139 #include <sys/rnd.h>
140 #endif
141 #ifndef PIPE_SOCKETPAIR
142 #include <sys/pipe.h>
143 #endif
144 #ifdef LKM
145 #include <sys/lkm.h>
146 #endif
147 #ifdef VERIFIED_EXEC
148 #include <sys/verified_exec.h>
149 #endif
150 #include <net80211/ieee80211_netbsd.h>
151 
152 #include <sys/syscall.h>
153 #include <sys/sa.h>
154 #include <sys/syscallargs.h>
155 
156 #include <ufs/ufs/quota.h>
157 
158 #include <miscfs/genfs/genfs.h>
159 #include <miscfs/syncfs/syncfs.h>
160 
161 #include <machine/cpu.h>
162 
163 #include <uvm/uvm.h>
164 
165 #include <dev/cons.h>
166 
167 #include <net/if.h>
168 #include <net/raw_cb.h>
169 
170 extern struct proc proc0;
171 extern struct lwp lwp0;
172 extern struct cwdinfo cwdi0;
173 
174 #ifndef curlwp
175 struct	lwp *curlwp = &lwp0;
176 #endif
177 struct	proc *initproc;
178 
179 struct	vnode *rootvp, *swapdev_vp;
180 int	boothowto;
181 int	cold = 1;			/* still working on startup */
182 struct	timeval boottime;
183 time_t	rootfstime;			/* recorded root fs time, if known */
184 
185 volatile int start_init_exec;		/* semaphore for start_init() */
186 
187 static void check_console(struct lwp *l);
188 static void start_init(void *);
189 void main(void);
190 
191 /*
192  * System startup; initialize the world, create process 0, mount root
193  * filesystem, and fork to create init and pagedaemon.  Most of the
194  * hard work is done in the lower-level initialization routines including
195  * startup(), which does memory initialization and autoconfiguration.
196  */
197 void
198 main(void)
199 {
200 	struct lwp *l;
201 	struct proc *p;
202 	struct pdevinit *pdev;
203 	int s, error;
204 	extern struct pdevinit pdevinit[];
205 	extern void schedcpu(void *);
206 #ifdef NVNODE_IMPLICIT
207 	int usevnodes;
208 #endif
209 
210 	/*
211 	 * Initialize the current LWP pointer (curlwp) before
212 	 * any possible traps/probes to simplify trap processing.
213 	 */
214 	l = &lwp0;
215 	curlwp = l;
216 	l->l_cpu = curcpu();
217 	l->l_proc = &proc0;
218 	l->l_lid = 1;
219 
220 	/*
221 	 * Attempt to find console and initialize
222 	 * in case of early panic or other messages.
223 	 */
224 	consinit();
225 
226 	KERNEL_LOCK_INIT();
227 
228 	uvm_init();
229 
230 	/* Do machine-dependent initialization. */
231 	cpu_startup();
232 
233 	/* Initialize callouts. */
234 	callout_startup();
235 
236 	/* Initialize the buffer cache */
237 	bufinit();
238 
239 	/*
240 	 * Initialize mbuf's.  Do this now because we might attempt to
241 	 * allocate mbufs or mbuf clusters during autoconfiguration.
242 	 */
243 	mbinit();
244 
245 	/* Initialize sockets. */
246 	soinit();
247 
248 #ifdef KCONT
249 	/* Initialize kcont. */
250         kcont_init();
251 #endif
252 
253 	/*
254 	 * The following things must be done before autoconfiguration.
255 	 */
256 	evcnt_init();		/* initialize event counters */
257 #if NRND > 0
258 	rnd_init();		/* initialize RNG */
259 #endif
260 	/* Initialize the sysctl subsystem. */
261 	sysctl_init();
262 
263 	/* Initialize process and pgrp structures. */
264 	procinit();
265 
266 	/* Initialize signal-related data structures. */
267 	signal_init();
268 
269 	/* Create process 0 (the swapper). */
270 	proc0_init();
271 
272 	/*
273 	 * Charge root for one process.
274 	 */
275 	(void)chgproccnt(0, 1);
276 
277 	rqinit();
278 
279 	/* Initialize the file systems. */
280 #ifdef NVNODE_IMPLICIT
281 	/*
282 	 * If maximum number of vnodes in namei vnode cache is not explicitly
283 	 * defined in kernel config, adjust the number such as we use roughly
284 	 * 1.0% of memory for vnode cache (but not less than NVNODE vnodes).
285 	 */
286 	usevnodes = (ptoa((unsigned)physmem) / 100) / sizeof(struct vnode);
287 	if (usevnodes > desiredvnodes)
288 		desiredvnodes = usevnodes;
289 #endif
290 	vfsinit();
291 
292 	/* Configure the system hardware.  This will enable interrupts. */
293 	configure();
294 
295 	ubc_init();		/* must be after autoconfig */
296 
297 	/* Lock the kernel on behalf of proc0. */
298 	KERNEL_PROC_LOCK(l);
299 
300 #ifdef SYSVSHM
301 	/* Initialize System V style shared memory. */
302 	shminit();
303 #endif
304 
305 #ifdef SYSVSEM
306 	/* Initialize System V style semaphores. */
307 	seminit();
308 #endif
309 
310 #ifdef SYSVMSG
311 	/* Initialize System V style message queues. */
312 	msginit();
313 #endif
314 
315 #ifdef P1003_1B_SEMAPHORE
316 	/* Initialize posix semaphores */
317 	ksem_init();
318 #endif
319 
320 #ifdef VERIFIED_EXEC
321 	  /*
322 	   * Initialise the fingerprint operations vectors before
323 	   * fingerprints can be loaded.
324 	   */
325 	veriexec_init_fp_ops();
326 #endif
327 
328 	/* Attach pseudo-devices. */
329 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
330 		(*pdev->pdev_attach)(pdev->pdev_count);
331 
332 #ifdef	FAST_IPSEC
333 	/* Attach network crypto subsystem */
334 	ipsec_attach();
335 #endif
336 
337 	/*
338 	 * Initialize protocols.  Block reception of incoming packets
339 	 * until everything is ready.
340 	 */
341 	s = splnet();
342 	ifinit();
343 	domaininit();
344 	if_attachdomain();
345 	splx(s);
346 
347 #ifdef GPROF
348 	/* Initialize kernel profiling. */
349 	kmstartup();
350 #endif
351 
352 	/* Initialize system accouting. */
353 	acct_init();
354 
355 	/* Kick off timeout driven events by calling first time. */
356 	schedcpu(NULL);
357 
358 	/*
359 	 * Create process 1 (init(8)).  We do this now, as Unix has
360 	 * historically had init be process 1, and changing this would
361 	 * probably upset a lot of people.
362 	 *
363 	 * Note that process 1 won't immediately exec init(8), but will
364 	 * wait for us to inform it that the root file system has been
365 	 * mounted.
366 	 */
367 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
368 		panic("fork init");
369 
370 	/*
371 	 * Create any kernel threads who's creation was deferred because
372 	 * initproc had not yet been created.
373 	 */
374 	kthread_run_deferred_queue();
375 
376 	/*
377 	 * Now that device driver threads have been created, wait for
378 	 * them to finish any deferred autoconfiguration.  Note we don't
379 	 * need to lock this semaphore, since we haven't booted any
380 	 * secondary processors, yet.
381 	 */
382 	while (config_pending)
383 		(void) tsleep(&config_pending, PWAIT, "cfpend", 0);
384 
385 	/*
386 	 * Finalize configuration now that all real devices have been
387 	 * found.  This needs to be done before the root device is
388 	 * selected, since finalization may create the root device.
389 	 */
390 	config_finalize();
391 
392 	/*
393 	 * Now that autoconfiguration has completed, we can determine
394 	 * the root and dump devices.
395 	 */
396 	cpu_rootconf();
397 	cpu_dumpconf();
398 
399 	/* Mount the root file system. */
400 	do {
401 		domountroothook();
402 		if ((error = vfs_mountroot())) {
403 			printf("cannot mount root, error = %d\n", error);
404 			boothowto |= RB_ASKNAME;
405 			setroot(root_device,
406 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
407 		}
408 	} while (error != 0);
409 	mountroothook_destroy();
410 
411 	/*
412 	 * Initialise the time-of-day clock, passing the time recorded
413 	 * in the root filesystem (if any) for use by systems that
414 	 * don't have a non-volatile time-of-day device.
415 	 */
416 	inittodr(rootfstime);
417 
418 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
419 #ifdef ROOTFS_MAGICLINKS
420 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_MAGICLINKS;
421 #endif
422 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
423 
424 	/*
425 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
426 	 * reference it.
427 	 */
428 	error = VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode);
429 	if (error)
430 		panic("cannot find root vnode, error=%d", error);
431 	cwdi0.cwdi_cdir = rootvnode;
432 	VREF(cwdi0.cwdi_cdir);
433 	VOP_UNLOCK(rootvnode, 0);
434 	cwdi0.cwdi_rdir = NULL;
435 
436 	/*
437 	 * Now that root is mounted, we can fixup initproc's CWD
438 	 * info.  All other processes are kthreads, which merely
439 	 * share proc0's CWD info.
440 	 */
441 	initproc->p_cwdi->cwdi_cdir = rootvnode;
442 	VREF(initproc->p_cwdi->cwdi_cdir);
443 	initproc->p_cwdi->cwdi_rdir = NULL;
444 
445 	/*
446 	 * Now can look at time, having had a chance to verify the time
447 	 * from the file system.  Reset p->p_rtime as it may have been
448 	 * munched in mi_switch() after the time got set.
449 	 */
450 	proclist_lock_read();
451 	s = splsched();
452 	LIST_FOREACH(p, &allproc, p_list) {
453 		KASSERT((p->p_flag & P_MARKER) == 0);
454 		p->p_stats->p_start = mono_time = boottime = time;
455 		LIST_FOREACH(l, &p->p_lwps, l_sibling) {
456 			if (l->l_cpu != NULL)
457 				l->l_cpu->ci_schedstate.spc_runtime = time;
458 		}
459 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
460 	}
461 	splx(s);
462 	proclist_unlock_read();
463 
464 	/* Create the pageout daemon kernel thread. */
465 	uvm_swap_init();
466 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
467 		panic("fork pagedaemon");
468 
469 	/* Create the filesystem syncer kernel thread. */
470 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
471 		panic("fork syncer");
472 
473 	/* Create the aiodone daemon kernel thread. */
474 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
475 	    "aiodoned"))
476 		panic("fork aiodoned");
477 
478 #if defined(MULTIPROCESSOR)
479 	/* Boot the secondary processors. */
480 	cpu_boot_secondary_processors();
481 #endif
482 
483 	/* Initialize exec structures */
484 	exec_init(1);
485 
486 	/*
487 	 * Okay, now we can let init(8) exec!  It's off to userland!
488 	 */
489 	start_init_exec = 1;
490 	wakeup(&start_init_exec);
491 
492 	/* The scheduler is an infinite loop. */
493 	uvm_scheduler();
494 	/* NOTREACHED */
495 }
496 
497 void
498 setrootfstime(time_t t)
499 {
500 
501 	rootfstime = t;
502 }
503 
504 static void
505 check_console(struct lwp *l)
506 {
507 	struct nameidata nd;
508 	int error;
509 
510 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", l);
511 	error = namei(&nd);
512 	if (error == 0)
513 		vrele(nd.ni_vp);
514 	else if (error == ENOENT)
515 		printf("warning: no /dev/console\n");
516 	else
517 		printf("warning: lookup /dev/console: error %d\n", error);
518 }
519 
520 /*
521  * List of paths to try when searching for "init".
522  */
523 static const char *initpaths[] = {
524 	"/sbin/init",
525 	"/sbin/oinit",
526 	"/sbin/init.bak",
527 	NULL,
528 };
529 
530 /*
531  * Start the initial user process; try exec'ing each pathname in "initpaths".
532  * The program is invoked with one argument containing the boot flags.
533  */
534 static void
535 start_init(void *arg)
536 {
537 	struct lwp *l = arg;
538 	struct proc *p = l->l_proc;
539 	vaddr_t addr;
540 	struct sys_execve_args /* {
541 		syscallarg(const char *) path;
542 		syscallarg(char * const *) argp;
543 		syscallarg(char * const *) envp;
544 	} */ args;
545 	int options, i, error;
546 	register_t retval[2];
547 	char flags[4], *flagsp;
548 	const char *path, *slash;
549 	char *ucp, **uap, *arg0, *arg1 = NULL;
550 	char ipath[129];
551 	int ipx, len;
552 
553 	/*
554 	 * Now in process 1.
555 	 */
556 	strncpy(p->p_comm, "init", MAXCOMLEN);
557 
558 	/*
559 	 * Wait for main() to tell us that it's safe to exec.
560 	 */
561 	while (start_init_exec == 0)
562 		(void) tsleep(&start_init_exec, PWAIT, "initexec", 0);
563 
564 	/*
565 	 * This is not the right way to do this.  We really should
566 	 * hand-craft a descriptor onto /dev/console to hand to init,
567 	 * but that's a _lot_ more work, and the benefit from this easy
568 	 * hack makes up for the "good is the enemy of the best" effect.
569 	 */
570 	check_console(l);
571 
572 	/*
573 	 * Need just enough stack to hold the faked-up "execve()" arguments.
574 	 */
575 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
576 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
577                     NULL, UVM_UNKNOWN_OFFSET, 0,
578                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
579 		    UVM_ADV_NORMAL,
580                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
581 		panic("init: couldn't allocate argument space");
582 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
583 
584 	ipx = 0;
585 	while (1) {
586 		if (boothowto & RB_ASKNAME) {
587 			printf("init path");
588 			if (initpaths[ipx])
589 				printf(" (default %s)", initpaths[ipx]);
590 			printf(": ");
591 			len = cngetsn(ipath, sizeof(ipath)-1);
592 			if (len == 0) {
593 				if (initpaths[ipx])
594 					path = initpaths[ipx++];
595 				else
596 					continue;
597 			} else {
598 				ipath[len] = '\0';
599 				path = ipath;
600 			}
601 		} else {
602 			if ((path = initpaths[ipx++]) == NULL)
603 				break;
604 		}
605 
606 		ucp = (char *)USRSTACK;
607 
608 		/*
609 		 * Construct the boot flag argument.
610 		 */
611 		flagsp = flags;
612 		*flagsp++ = '-';
613 		options = 0;
614 
615 		if (boothowto & RB_SINGLE) {
616 			*flagsp++ = 's';
617 			options = 1;
618 		}
619 #ifdef notyet
620 		if (boothowto & RB_FASTBOOT) {
621 			*flagsp++ = 'f';
622 			options = 1;
623 		}
624 #endif
625 
626 		/*
627 		 * Move out the flags (arg 1), if necessary.
628 		 */
629 		if (options != 0) {
630 			*flagsp++ = '\0';
631 			i = flagsp - flags;
632 #ifdef DEBUG
633 			printf("init: copying out flags `%s' %d\n", flags, i);
634 #endif
635 			arg1 = STACK_ALLOC(ucp, i);
636 			ucp = STACK_MAX(arg1, i);
637 			(void)copyout((caddr_t)flags, arg1, i);
638 		}
639 
640 		/*
641 		 * Move out the file name (also arg 0).
642 		 */
643 		i = strlen(path) + 1;
644 #ifdef DEBUG
645 		printf("init: copying out path `%s' %d\n", path, i);
646 #else
647 		if (boothowto & RB_ASKNAME || path != initpaths[0])
648 			printf("init: trying %s\n", path);
649 #endif
650 		arg0 = STACK_ALLOC(ucp, i);
651 		ucp = STACK_MAX(arg0, i);
652 		(void)copyout(path, arg0, i);
653 
654 		/*
655 		 * Move out the arg pointers.
656 		 */
657 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
658 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
659 		SCARG(&args, path) = arg0;
660 		SCARG(&args, argp) = uap;
661 		SCARG(&args, envp) = NULL;
662 		slash = strrchr(path, '/');
663 		if (slash)
664 			(void)suword((caddr_t)uap++,
665 			    (long)arg0 + (slash + 1 - path));
666 		else
667 			(void)suword((caddr_t)uap++, (long)arg0);
668 		if (options != 0)
669 			(void)suword((caddr_t)uap++, (long)arg1);
670 		(void)suword((caddr_t)uap++, 0);	/* terminator */
671 
672 		/*
673 		 * Now try to exec the program.  If can't for any reason
674 		 * other than it doesn't exist, complain.
675 		 */
676 		error = sys_execve(l, &args, retval);
677 		if (error == 0 || error == EJUSTRETURN) {
678 			KERNEL_PROC_UNLOCK(l);
679 			return;
680 		}
681 		printf("exec %s: error %d\n", path, error);
682 	}
683 	printf("init: not found\n");
684 	panic("no init");
685 }
686