xref: /netbsd-src/sys/kern/init_main.c (revision 1ca5c1b28139779176bd5c13ad7c5f25c0bcd5f8)
1 /*	$NetBSD: init_main.c,v 1.197 2002/01/01 09:17:28 perry Exp $	*/
2 
3 /*
4  * Copyright (c) 1995 Christopher G. Demetriou.  All rights reserved.
5  * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  * (c) UNIX System Laboratories, Inc.
8  * All or some portions of this file are derived from material licensed
9  * to the University of California by American Telephone and Telegraph
10  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11  * the permission of UNIX System Laboratories, Inc.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgement:
23  *	This product includes software developed by the University of
24  *	California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
42  */
43 
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.197 2002/01/01 09:17:28 perry Exp $");
46 
47 #include "fs_nfs.h"
48 #include "opt_nfsserver.h"
49 #include "opt_sysv.h"
50 #include "opt_maxuprc.h"
51 #include "opt_multiprocessor.h"
52 #include "opt_new_pipe.h"
53 #include "opt_syscall_debug.h"
54 
55 #include "rnd.h"
56 
57 #include <sys/param.h>
58 #include <sys/acct.h>
59 #include <sys/filedesc.h>
60 #include <sys/file.h>
61 #include <sys/errno.h>
62 #include <sys/callout.h>
63 #include <sys/kernel.h>
64 #include <sys/mount.h>
65 #include <sys/map.h>
66 #include <sys/proc.h>
67 #include <sys/kthread.h>
68 #include <sys/resourcevar.h>
69 #include <sys/signalvar.h>
70 #include <sys/systm.h>
71 #include <sys/vnode.h>
72 #include <sys/tty.h>
73 #include <sys/conf.h>
74 #include <sys/disklabel.h>
75 #include <sys/buf.h>
76 #include <sys/device.h>
77 #include <sys/exec.h>
78 #include <sys/socketvar.h>
79 #include <sys/protosw.h>
80 #include <sys/reboot.h>
81 #include <sys/user.h>
82 #include <sys/sysctl.h>
83 #ifdef SYSVSHM
84 #include <sys/shm.h>
85 #endif
86 #ifdef SYSVSEM
87 #include <sys/sem.h>
88 #endif
89 #ifdef SYSVMSG
90 #include <sys/msg.h>
91 #endif
92 #include <sys/domain.h>
93 #include <sys/mbuf.h>
94 #include <sys/namei.h>
95 #if NRND > 0
96 #include <sys/rnd.h>
97 #endif
98 #ifdef NEW_PIPE
99 #include <sys/pipe.h>
100 #endif
101 
102 #include <sys/syscall.h>
103 #include <sys/syscallargs.h>
104 
105 #include <ufs/ufs/quota.h>
106 
107 #include <miscfs/genfs/genfs.h>
108 #include <miscfs/syncfs/syncfs.h>
109 
110 #include <machine/cpu.h>
111 
112 #include <uvm/uvm.h>
113 
114 #include <net/if.h>
115 #include <net/raw_cb.h>
116 
117 const char copyright[] =
118 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002\n"
119 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
120 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
121 "    The Regents of the University of California.  All rights reserved.\n"
122 "\n";
123 
124 /* Components of the first process -- never freed. */
125 struct	session session0;
126 struct	pgrp pgrp0;
127 struct	proc proc0;
128 struct	pcred cred0;
129 struct	filedesc0 filedesc0;
130 struct	cwdinfo cwdi0;
131 struct	plimit limit0;
132 struct	vmspace vmspace0;
133 struct	sigacts sigacts0;
134 #ifndef curproc
135 struct	proc *curproc = &proc0;
136 #endif
137 struct	proc *initproc;
138 
139 int	cmask = CMASK;
140 extern	struct user *proc0paddr;
141 
142 struct	vnode *rootvp, *swapdev_vp;
143 int	boothowto;
144 int	cold = 1;			/* still working on startup */
145 struct	timeval boottime;
146 
147 __volatile int start_init_exec;		/* semaphore for start_init() */
148 
149 static void check_console(struct proc *p);
150 static void start_init(void *);
151 void main(void);
152 
153 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
154 
155 /*
156  * System startup; initialize the world, create process 0, mount root
157  * filesystem, and fork to create init and pagedaemon.  Most of the
158  * hard work is done in the lower-level initialization routines including
159  * startup(), which does memory initialization and autoconfiguration.
160  */
161 void
162 main(void)
163 {
164 	struct proc *p;
165 	struct pdevinit *pdev;
166 	int i, s, error;
167 	rlim_t lim;
168 	extern struct pdevinit pdevinit[];
169 	extern void schedcpu(void *);
170 	extern void disk_init(void);
171 #if defined(NFSSERVER) || defined(NFS)
172 	extern void nfs_init(void);
173 #endif
174 #ifdef NVNODE_IMPLICIT
175 	int usevnodes;
176 #endif
177 
178 	/*
179 	 * Initialize the current process pointer (curproc) before
180 	 * any possible traps/probes to simplify trap processing.
181 	 */
182 	p = &proc0;
183 	curproc = p;
184 	p->p_cpu = curcpu();
185 	/*
186 	 * Attempt to find console and initialize
187 	 * in case of early panic or other messages.
188 	 */
189 	consinit();
190 	printf("%s", copyright);
191 
192 	KERNEL_LOCK_INIT();
193 
194 	uvm_init();
195 
196 	/* Do machine-dependent initialization. */
197 	cpu_startup();
198 
199 	/* Initialize callouts. */
200 	callout_startup();
201 
202 	/*
203 	 * Initialize mbuf's.  Do this now because we might attempt to
204 	 * allocate mbufs or mbuf clusters during autoconfiguration.
205 	 */
206 	mbinit();
207 
208 	/* Initialize sockets. */
209 	soinit();
210 
211 	/*
212 	 * The following 3 things must be done before autoconfiguration.
213 	 */
214 	disk_init();		/* initialize disk list */
215 	tty_init();		/* initialize tty list */
216 #if NRND > 0
217 	rnd_init();		/* initialize RNG */
218 #endif
219 
220 	/* Initialize the sysctl subsystem. */
221 	sysctl_init();
222 
223 	/*
224 	 * Initialize process and pgrp structures.
225 	 */
226 	procinit();
227 
228 	/*
229 	 * Create process 0 (the swapper).
230 	 */
231 	s = proclist_lock_write();
232 	LIST_INSERT_HEAD(&allproc, p, p_list);
233 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
234 	proclist_unlock_write(s);
235 
236 	p->p_pgrp = &pgrp0;
237 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
238 	LIST_INIT(&pgrp0.pg_members);
239 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
240 
241 	pgrp0.pg_session = &session0;
242 	session0.s_count = 1;
243 	session0.s_sid = p->p_pid;
244 	session0.s_leader = p;
245 
246 	/*
247 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
248 	 * init(8) when they exit.  init(8) can easily wait them out
249 	 * for us.
250 	 */
251 	p->p_flag = P_INMEM | P_SYSTEM | P_NOCLDWAIT;
252 	p->p_stat = SONPROC;
253 	p->p_nice = NZERO;
254 	p->p_emul = &emul_netbsd;
255 #ifdef __HAVE_SYSCALL_INTERN
256 	(*p->p_emul->e_syscall_intern)(p);
257 #endif
258 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
259 
260 	callout_init(&p->p_realit_ch);
261 	callout_init(&p->p_tsleep_ch);
262 
263 	/* Create credentials. */
264 	cred0.p_refcnt = 1;
265 	p->p_cred = &cred0;
266 	p->p_ucred = crget();
267 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
268 
269 	/* Create the file descriptor table. */
270 	finit();
271 	p->p_fd = &filedesc0.fd_fd;
272 	fdinit1(&filedesc0);
273 
274 	/* Create the CWD info. */
275 	p->p_cwdi = &cwdi0;
276 	cwdi0.cwdi_cmask = cmask;
277 	cwdi0.cwdi_refcnt = 1;
278 
279 	/* Create the limits structures. */
280 	p->p_limit = &limit0;
281 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
282 		limit0.pl_rlimit[i].rlim_cur =
283 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
284 
285 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
286 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
287 	    maxfiles < NOFILE ? maxfiles : NOFILE;
288 
289 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
290 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
291 	    maxproc < MAXUPRC ? maxproc : MAXUPRC;
292 
293 	lim = ptoa(uvmexp.free);
294 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
295 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
296 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
297 	limit0.pl_corename = defcorename;
298 	limit0.p_refcnt = 1;
299 
300 	/*
301 	 * Initialize proc0's vmspace, which uses the kernel pmap.
302 	 * All kernel processes (which never have user space mappings)
303 	 * share proc0's vmspace, and thus, the kernel pmap.
304 	 */
305 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
306 	    trunc_page(VM_MAX_ADDRESS));
307 	p->p_vmspace = &vmspace0;
308 
309 	p->p_addr = proc0paddr;				/* XXX */
310 
311 	/*
312 	 * We continue to place resource usage info in the
313 	 * user struct so they're pageable.
314 	 */
315 	p->p_stats = &p->p_addr->u_stats;
316 
317 	/*
318 	 * Charge root for one process.
319 	 */
320 	(void)chgproccnt(0, 1);
321 
322 	rqinit();
323 
324 	/* Configure virtual memory system, set vm rlimits. */
325 	uvm_init_limits(p);
326 
327 	/* Initialize the file systems. */
328 #if defined(NFSSERVER) || defined(NFS)
329 	nfs_init();			/* initialize server/shared data */
330 #endif
331 #ifdef NVNODE_IMPLICIT
332 	/*
333 	 * If maximum number of vnodes in namei vnode cache is not explicitly
334 	 * defined in kernel config, adjust the number such as we use roughly
335 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
336 	 */
337 	usevnodes = (ptoa((unsigned)physmem) / 200) / sizeof(struct vnode);
338 	if (usevnodes > desiredvnodes)
339 		desiredvnodes = usevnodes;
340 #endif
341 	vfsinit();
342 
343 	/* Configure the system hardware.  This will enable interrupts. */
344 	configure();
345 
346 	ubc_init();		/* must be after autoconfig */
347 
348 	/* Lock the kernel on behalf of proc0. */
349 	KERNEL_PROC_LOCK(p);
350 
351 #ifdef SYSVSHM
352 	/* Initialize System V style shared memory. */
353 	shminit();
354 #endif
355 
356 #ifdef SYSVSEM
357 	/* Initialize System V style semaphores. */
358 	seminit();
359 #endif
360 
361 #ifdef SYSVMSG
362 	/* Initialize System V style message queues. */
363 	msginit();
364 #endif
365 
366 	/* Attach pseudo-devices. */
367 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
368 		(*pdev->pdev_attach)(pdev->pdev_count);
369 
370 	/*
371 	 * Initialize protocols.  Block reception of incoming packets
372 	 * until everything is ready.
373 	 */
374 	s = splnet();
375 	ifinit();
376 	domaininit();
377 	splx(s);
378 
379 #ifdef GPROF
380 	/* Initialize kernel profiling. */
381 	kmstartup();
382 #endif
383 
384 	/* Initialize system accouting. */
385 	acct_init();
386 
387 	/*
388 	 * Initialize signal-related data structures, and signal state
389 	 * for proc0.
390 	 */
391 	signal_init();
392 	p->p_sigacts = &sigacts0;
393 	siginit(p);
394 
395 	/* Kick off timeout driven events by calling first time. */
396 	schedcpu(NULL);
397 
398 	/*
399 	 * Create process 1 (init(8)).  We do this now, as Unix has
400 	 * historically had init be process 1, and changing this would
401 	 * probably upset a lot of people.
402 	 *
403 	 * Note that process 1 won't immediately exec init(8), but will
404 	 * wait for us to inform it that the root file system has been
405 	 * mounted.
406 	 */
407 	if (fork1(p, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
408 		panic("fork init");
409 
410 	/*
411 	 * Create any kernel threads who's creation was deferred because
412 	 * initproc had not yet been created.
413 	 */
414 	kthread_run_deferred_queue();
415 
416 	/*
417 	 * Now that device driver threads have been created, wait for
418 	 * them to finish any deferred autoconfiguration.  Note we don't
419 	 * need to lock this semaphore, since we haven't booted any
420 	 * secondary processors, yet.
421 	 */
422 	while (config_pending)
423 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
424 
425 	/*
426 	 * Now that autoconfiguration has completed, we can determine
427 	 * the root and dump devices.
428 	 */
429 	cpu_rootconf();
430 	cpu_dumpconf();
431 
432 	/* Mount the root file system. */
433 	do {
434 		domountroothook();
435 		if ((error = vfs_mountroot())) {
436 			printf("cannot mount root, error = %d\n", error);
437 			boothowto |= RB_ASKNAME;
438 			setroot(root_device,
439 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
440 		}
441 	} while (error != 0);
442 	mountroothook_destroy();
443 
444 	mountlist.cqh_first->mnt_flag |= MNT_ROOTFS;
445 	mountlist.cqh_first->mnt_op->vfs_refcount++;
446 
447 	/*
448 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
449 	 * reference it.
450 	 */
451 	if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
452 		panic("cannot find root vnode");
453 	cwdi0.cwdi_cdir = rootvnode;
454 	VREF(cwdi0.cwdi_cdir);
455 	VOP_UNLOCK(rootvnode, 0);
456 	cwdi0.cwdi_rdir = NULL;
457 
458 	/*
459 	 * Now that root is mounted, we can fixup initproc's CWD
460 	 * info.  All other processes are kthreads, which merely
461 	 * share proc0's CWD info.
462 	 */
463 	initproc->p_cwdi->cwdi_cdir = rootvnode;
464 	VREF(initproc->p_cwdi->cwdi_cdir);
465 	initproc->p_cwdi->cwdi_rdir = NULL;
466 
467 	/*
468 	 * Now can look at time, having had a chance to verify the time
469 	 * from the file system.  Reset p->p_rtime as it may have been
470 	 * munched in mi_switch() after the time got set.
471 	 */
472 	proclist_lock_read();
473 	s = splsched();
474 	for (p = LIST_FIRST(&allproc); p != NULL;
475 	     p = LIST_NEXT(p, p_list)) {
476 		p->p_stats->p_start = mono_time = boottime = time;
477 		if (p->p_cpu != NULL)
478 			p->p_cpu->ci_schedstate.spc_runtime = time;
479 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
480 	}
481 	splx(s);
482 	proclist_unlock_read();
483 
484 	/* Create the pageout daemon kernel thread. */
485 	uvm_swap_init();
486 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
487 		panic("fork pagedaemon");
488 
489 	/* Create the process reaper kernel thread. */
490 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
491 		panic("fork reaper");
492 
493 	/* Create the filesystem syncer kernel thread. */
494 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
495 		panic("fork syncer");
496 
497 	/* Create the aiodone daemon kernel thread. */
498 	if (kthread_create1(uvm_aiodone_daemon, NULL, NULL, "aiodoned"))
499 		panic("fork aiodoned");
500 
501 #if defined(MULTIPROCESSOR)
502 	/* Boot the secondary processors. */
503 	cpu_boot_secondary_processors();
504 #endif
505 
506 	/* Initialize exec structures */
507 	exec_init(1);
508 
509 #ifdef NEW_PIPE
510 	/* Initialize pipe structures */
511 	pipe_init();
512 #endif
513 
514 	/*
515 	 * Okay, now we can let init(8) exec!  It's off to userland!
516 	 */
517 	start_init_exec = 1;
518 	wakeup((void *)&start_init_exec);
519 
520 	/* The scheduler is an infinite loop. */
521 	uvm_scheduler();
522 	/* NOTREACHED */
523 }
524 
525 static void
526 check_console(struct proc *p)
527 {
528 	struct nameidata nd;
529 	int error;
530 
531 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
532 	error = namei(&nd);
533 	if (error == 0)
534 		vrele(nd.ni_vp);
535 	else if (error == ENOENT)
536 		printf("warning: no /dev/console\n");
537 	else
538 		printf("warning: lookup /dev/console: error %d\n", error);
539 }
540 
541 /*
542  * List of paths to try when searching for "init".
543  */
544 static const char *initpaths[] = {
545 	"/sbin/init",
546 	"/sbin/oinit",
547 	"/sbin/init.bak",
548 	NULL,
549 };
550 
551 /*
552  * Start the initial user process; try exec'ing each pathname in "initpaths".
553  * The program is invoked with one argument containing the boot flags.
554  */
555 static void
556 start_init(void *arg)
557 {
558 	struct proc *p = arg;
559 	vaddr_t addr;
560 	struct sys_execve_args /* {
561 		syscallarg(const char *) path;
562 		syscallarg(char * const *) argp;
563 		syscallarg(char * const *) envp;
564 	} */ args;
565 	int options, i, error;
566 	register_t retval[2];
567 	char flags[4], *flagsp;
568 	const char **pathp, *path, *slash;
569 	char *ucp, **uap, *arg0, *arg1 = NULL;
570 
571 	/*
572 	 * Now in process 1.
573 	 */
574 	strncpy(p->p_comm, "init", MAXCOMLEN);
575 
576 	/*
577 	 * Wait for main() to tell us that it's safe to exec.
578 	 */
579 	while (start_init_exec == 0)
580 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
581 
582 	/*
583 	 * This is not the right way to do this.  We really should
584 	 * hand-craft a descriptor onto /dev/console to hand to init,
585 	 * but that's a _lot_ more work, and the benefit from this easy
586 	 * hack makes up for the "good is the enemy of the best" effect.
587 	 */
588 	check_console(p);
589 
590 	/*
591 	 * Need just enough stack to hold the faked-up "execve()" arguments.
592 	 */
593 	addr = USRSTACK - PAGE_SIZE;
594 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
595                     NULL, UVM_UNKNOWN_OFFSET, 0,
596                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
597 		    UVM_ADV_NORMAL,
598                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
599 		panic("init: couldn't allocate argument space");
600 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
601 
602 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
603 		ucp = (char *)(addr + PAGE_SIZE);
604 
605 		/*
606 		 * Construct the boot flag argument.
607 		 */
608 		flagsp = flags;
609 		*flagsp++ = '-';
610 		options = 0;
611 
612 		if (boothowto & RB_SINGLE) {
613 			*flagsp++ = 's';
614 			options = 1;
615 		}
616 #ifdef notyet
617 		if (boothowto & RB_FASTBOOT) {
618 			*flagsp++ = 'f';
619 			options = 1;
620 		}
621 #endif
622 
623 		/*
624 		 * Move out the flags (arg 1), if necessary.
625 		 */
626 		if (options != 0) {
627 			*flagsp++ = '\0';
628 			i = flagsp - flags;
629 #ifdef DEBUG
630 			printf("init: copying out flags `%s' %d\n", flags, i);
631 #endif
632 			(void)copyout((caddr_t)flags, (caddr_t)(ucp -= i), i);
633 			arg1 = ucp;
634 		}
635 
636 		/*
637 		 * Move out the file name (also arg 0).
638 		 */
639 		i = strlen(path) + 1;
640 #ifdef DEBUG
641 		printf("init: copying out path `%s' %d\n", path, i);
642 #endif
643 		(void)copyout((caddr_t)path, (caddr_t)(ucp -= i), i);
644 		arg0 = ucp;
645 
646 		/*
647 		 * Move out the arg pointers.
648 		 */
649 		uap = (char **)((long)ucp & ~ALIGNBYTES);
650 		(void)suword((caddr_t)--uap, 0);	/* terminator */
651 		if (options != 0)
652 			(void)suword((caddr_t)--uap, (long)arg1);
653 		slash = strrchr(path, '/');
654 		if (slash)
655 			(void)suword((caddr_t)--uap,
656 			    (long)arg0 + (slash + 1 - path));
657 		else
658 			(void)suword((caddr_t)--uap, (long)arg0);
659 
660 		/*
661 		 * Point at the arguments.
662 		 */
663 		SCARG(&args, path) = arg0;
664 		SCARG(&args, argp) = uap;
665 		SCARG(&args, envp) = NULL;
666 
667 		/*
668 		 * Now try to exec the program.  If can't for any reason
669 		 * other than it doesn't exist, complain.
670 		 */
671 		error = sys_execve(p, &args, retval);
672 		if (error == 0 || error == EJUSTRETURN) {
673 			KERNEL_PROC_UNLOCK(p);
674 			return;
675 		}
676 		if (error != ENOENT)
677 			printf("exec %s: error %d\n", path, error);
678 	}
679 	printf("init: not found\n");
680 	panic("no init");
681 }
682