xref: /netbsd-src/sys/kern/init_main.c (revision 17306b8fd0952c7489f93f0230818481e5a1e2c9)
1 /*	$NetBSD: init_main.c,v 1.192 2001/06/16 12:00:02 jdolecek 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 "fs_nfs.h"
45 #include "opt_nfsserver.h"
46 #include "opt_sysv.h"
47 #include "opt_maxuprc.h"
48 #include "opt_multiprocessor.h"
49 #include "opt_new_pipe.h"
50 #include "opt_syscall_debug.h"
51 
52 #include "rnd.h"
53 
54 #include <sys/param.h>
55 #include <sys/acct.h>
56 #include <sys/filedesc.h>
57 #include <sys/file.h>
58 #include <sys/errno.h>
59 #include <sys/callout.h>
60 #include <sys/kernel.h>
61 #include <sys/mount.h>
62 #include <sys/map.h>
63 #include <sys/proc.h>
64 #include <sys/kthread.h>
65 #include <sys/resourcevar.h>
66 #include <sys/signalvar.h>
67 #include <sys/systm.h>
68 #include <sys/vnode.h>
69 #include <sys/tty.h>
70 #include <sys/conf.h>
71 #include <sys/disklabel.h>
72 #include <sys/buf.h>
73 #include <sys/device.h>
74 #include <sys/exec.h>
75 #include <sys/socketvar.h>
76 #include <sys/protosw.h>
77 #include <sys/reboot.h>
78 #include <sys/user.h>
79 #include <sys/sysctl.h>
80 #ifdef SYSVSHM
81 #include <sys/shm.h>
82 #endif
83 #ifdef SYSVSEM
84 #include <sys/sem.h>
85 #endif
86 #ifdef SYSVMSG
87 #include <sys/msg.h>
88 #endif
89 #include <sys/domain.h>
90 #include <sys/mbuf.h>
91 #include <sys/namei.h>
92 #if NRND > 0
93 #include <sys/rnd.h>
94 #endif
95 #ifdef NEW_PIPE
96 #include <sys/pipe.h>
97 #endif
98 
99 #include <sys/syscall.h>
100 #include <sys/syscallargs.h>
101 
102 #include <ufs/ufs/quota.h>
103 
104 #include <miscfs/genfs/genfs.h>
105 #include <miscfs/syncfs/syncfs.h>
106 
107 #include <machine/cpu.h>
108 
109 #include <uvm/uvm.h>
110 
111 #include <net/if.h>
112 #include <net/raw_cb.h>
113 
114 const char copyright[] = "\n"
115 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001\n"
116 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
117 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
118 "    The Regents of the University of California.  All rights reserved.\n"
119 "\n";
120 
121 /* Components of the first process -- never freed. */
122 struct	session session0;
123 struct	pgrp pgrp0;
124 struct	proc proc0;
125 struct	pcred cred0;
126 struct	filedesc0 filedesc0;
127 struct	cwdinfo cwdi0;
128 struct	plimit limit0;
129 struct	vmspace vmspace0;
130 struct	sigacts sigacts0;
131 #ifndef curproc
132 struct	proc *curproc = &proc0;
133 #endif
134 struct	proc *initproc;
135 
136 int	cmask = CMASK;
137 extern	struct user *proc0paddr;
138 
139 struct	vnode *rootvp, *swapdev_vp;
140 int	boothowto;
141 int	cold = 1;			/* still working on startup */
142 struct	timeval boottime;
143 
144 __volatile int start_init_exec;		/* semaphore for start_init() */
145 
146 static void check_console(struct proc *p);
147 static void start_init(void *);
148 void main(void);
149 
150 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
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 void
159 main(void)
160 {
161 	struct proc *p;
162 	struct pdevinit *pdev;
163 	int i, s, error;
164 	rlim_t lim;
165 	extern struct pdevinit pdevinit[];
166 	extern void schedcpu(void *);
167 	extern void disk_init(void);
168 #if defined(NFSSERVER) || defined(NFS)
169 	extern void nfs_init(void);
170 #endif
171 #ifdef NVNODE_IMPLICIT
172 	int usevnodes;
173 #endif
174 
175 	/*
176 	 * Initialize the current process pointer (curproc) before
177 	 * any possible traps/probes to simplify trap processing.
178 	 */
179 	p = &proc0;
180 	curproc = p;
181 	p->p_cpu = curcpu();
182 	/*
183 	 * Attempt to find console and initialize
184 	 * in case of early panic or other messages.
185 	 */
186 	consinit();
187 	printf("%s", copyright);
188 
189 	KERNEL_LOCK_INIT();
190 
191 	uvm_init();
192 
193 	/* Do machine-dependent initialization. */
194 	cpu_startup();
195 
196 	/* Initialize callouts. */
197 	callout_startup();
198 
199 	/*
200 	 * Initialize mbuf's.  Do this now because we might attempt to
201 	 * allocate mbufs or mbuf clusters during autoconfiguration.
202 	 */
203 	mbinit();
204 
205 	/* Initialize sockets. */
206 	soinit();
207 
208 	/*
209 	 * The following 3 things must be done before autoconfiguration.
210 	 */
211 	disk_init();		/* initialize disk list */
212 	tty_init();		/* initialize tty list */
213 #if NRND > 0
214 	rnd_init();		/* initialize RNG */
215 #endif
216 
217 	/* Initialize the sysctl subsystem. */
218 	sysctl_init();
219 
220 	/*
221 	 * Initialize process and pgrp structures.
222 	 */
223 	procinit();
224 
225 	/*
226 	 * Create process 0 (the swapper).
227 	 */
228 	s = proclist_lock_write();
229 	LIST_INSERT_HEAD(&allproc, p, p_list);
230 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
231 	proclist_unlock_write(s);
232 
233 	p->p_pgrp = &pgrp0;
234 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
235 	LIST_INIT(&pgrp0.pg_members);
236 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
237 
238 	pgrp0.pg_session = &session0;
239 	session0.s_count = 1;
240 	session0.s_sid = p->p_pid;
241 	session0.s_leader = p;
242 
243 	/*
244 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
245 	 * init(8) when they exit.  init(8) can easily wait them out
246 	 * for us.
247 	 */
248 	p->p_flag = P_INMEM | P_SYSTEM | P_NOCLDWAIT;
249 	p->p_stat = SONPROC;
250 	p->p_nice = NZERO;
251 	p->p_emul = &emul_netbsd;
252 #ifdef __HAVE_SYSCALL_INTERN
253 	(*p->p_emul->e_syscall_intern)(p);
254 #endif
255 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
256 
257 	callout_init(&p->p_realit_ch);
258 	callout_init(&p->p_tsleep_ch);
259 
260 	/* Create credentials. */
261 	cred0.p_refcnt = 1;
262 	p->p_cred = &cred0;
263 	p->p_ucred = crget();
264 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
265 
266 	/* Create the file descriptor table. */
267 	finit();
268 	p->p_fd = &filedesc0.fd_fd;
269 	fdinit1(&filedesc0);
270 
271 	/* Create the CWD info. */
272 	p->p_cwdi = &cwdi0;
273 	cwdi0.cwdi_cmask = cmask;
274 	cwdi0.cwdi_refcnt = 1;
275 
276 	/* Create the limits structures. */
277 	p->p_limit = &limit0;
278 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
279 		limit0.pl_rlimit[i].rlim_cur =
280 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
281 
282 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
283 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
284 	    maxfiles < NOFILE ? maxfiles : NOFILE;
285 
286 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
287 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
288 	    maxproc < MAXUPRC ? maxproc : MAXUPRC;
289 
290 	lim = ptoa(uvmexp.free);
291 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
292 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
293 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
294 	limit0.pl_corename = defcorename;
295 	limit0.p_refcnt = 1;
296 
297 	/*
298 	 * Initialize proc0's vmspace, which uses the kernel pmap.
299 	 * All kernel processes (which never have user space mappings)
300 	 * share proc0's vmspace, and thus, the kernel pmap.
301 	 */
302 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
303 	    trunc_page(VM_MAX_ADDRESS), TRUE);
304 	p->p_vmspace = &vmspace0;
305 
306 	p->p_addr = proc0paddr;				/* XXX */
307 
308 	/*
309 	 * We continue to place resource usage info in the
310 	 * user struct so they're pageable.
311 	 */
312 	p->p_stats = &p->p_addr->u_stats;
313 
314 	/*
315 	 * Charge root for one process.
316 	 */
317 	(void)chgproccnt(0, 1);
318 
319 	rqinit();
320 
321 	/* Configure virtual memory system, set vm rlimits. */
322 	uvm_init_limits(p);
323 
324 	/* Initialize the file systems. */
325 #if defined(NFSSERVER) || defined(NFS)
326 	nfs_init();			/* initialize server/shared data */
327 #endif
328 	vfsinit();
329 
330 	/* Configure the system hardware.  This will enable interrupts. */
331 	configure();
332 
333 	ubc_init();		/* must be after autoconfig */
334 
335 	/* Lock the kernel on behalf of proc0. */
336 	KERNEL_PROC_LOCK(p);
337 
338 #ifdef SYSVSHM
339 	/* Initialize System V style shared memory. */
340 	shminit();
341 #endif
342 
343 #ifdef SYSVSEM
344 	/* Initialize System V style semaphores. */
345 	seminit();
346 #endif
347 
348 #ifdef SYSVMSG
349 	/* Initialize System V style message queues. */
350 	msginit();
351 #endif
352 
353 	/* Attach pseudo-devices. */
354 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
355 		(*pdev->pdev_attach)(pdev->pdev_count);
356 
357 	/*
358 	 * Initialize protocols.  Block reception of incoming packets
359 	 * until everything is ready.
360 	 */
361 	s = splnet();
362 	ifinit();
363 	domaininit();
364 	splx(s);
365 
366 #ifdef GPROF
367 	/* Initialize kernel profiling. */
368 	kmstartup();
369 #endif
370 
371 	/* Initialize system accouting. */
372 	acct_init();
373 
374 	/*
375 	 * Initialize signal-related data structures, and signal state
376 	 * for proc0.
377 	 */
378 	signal_init();
379 	p->p_sigacts = &sigacts0;
380 	siginit(p);
381 
382 	/* Kick off timeout driven events by calling first time. */
383 	schedcpu(NULL);
384 
385 	/*
386 	 * Create process 1 (init(8)).  We do this now, as Unix has
387 	 * historically had init be process 1, and changing this would
388 	 * probably upset a lot of people.
389 	 *
390 	 * Note that process 1 won't immediately exec init(8), but will
391 	 * wait for us to inform it that the root file system has been
392 	 * mounted.
393 	 */
394 	if (fork1(p, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
395 		panic("fork init");
396 
397 	/*
398 	 * Create any kernel threads who's creation was deferred because
399 	 * initproc had not yet been created.
400 	 */
401 	kthread_run_deferred_queue();
402 
403 	/*
404 	 * Now that device driver threads have been created, wait for
405 	 * them to finish any deferred autoconfiguration.  Note we don't
406 	 * need to lock this semaphore, since we haven't booted any
407 	 * secondary processors, yet.
408 	 */
409 	while (config_pending)
410 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
411 
412 	/*
413 	 * Now that autoconfiguration has completed, we can determine
414 	 * the root and dump devices.
415 	 */
416 	cpu_rootconf();
417 	cpu_dumpconf();
418 
419 	/* Mount the root file system. */
420 	do {
421 		domountroothook();
422 		if ((error = vfs_mountroot())) {
423 			printf("cannot mount root, error = %d\n", error);
424 			boothowto |= RB_ASKNAME;
425 			setroot(root_device,
426 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
427 		}
428 	} while (error != 0);
429 	mountroothook_destroy();
430 
431 	mountlist.cqh_first->mnt_flag |= MNT_ROOTFS;
432 	mountlist.cqh_first->mnt_op->vfs_refcount++;
433 
434 	/*
435 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
436 	 * reference it.
437 	 */
438 	if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
439 		panic("cannot find root vnode");
440 	cwdi0.cwdi_cdir = rootvnode;
441 	VREF(cwdi0.cwdi_cdir);
442 	VOP_UNLOCK(rootvnode, 0);
443 	cwdi0.cwdi_rdir = NULL;
444 
445 	/*
446 	 * Now that root is mounted, we can fixup initproc's CWD
447 	 * info.  All other processes are kthreads, which merely
448 	 * share proc0's CWD info.
449 	 */
450 	initproc->p_cwdi->cwdi_cdir = rootvnode;
451 	VREF(initproc->p_cwdi->cwdi_cdir);
452 	initproc->p_cwdi->cwdi_rdir = NULL;
453 
454 	/*
455 	 * Now can look at time, having had a chance to verify the time
456 	 * from the file system.  Reset p->p_rtime as it may have been
457 	 * munched in mi_switch() after the time got set.
458 	 */
459 	proclist_lock_read();
460 	s = splsched();
461 	for (p = LIST_FIRST(&allproc); p != NULL;
462 	     p = LIST_NEXT(p, p_list)) {
463 		p->p_stats->p_start = mono_time = boottime = time;
464 		if (p->p_cpu != NULL)
465 			p->p_cpu->ci_schedstate.spc_runtime = time;
466 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
467 	}
468 	splx(s);
469 	proclist_unlock_read();
470 
471 	/* Create the pageout daemon kernel thread. */
472 	uvm_swap_init();
473 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
474 		panic("fork pagedaemon");
475 
476 	/* Create the process reaper kernel thread. */
477 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
478 		panic("fork reaper");
479 
480 	/* Create the filesystem syncer kernel thread. */
481 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
482 		panic("fork syncer");
483 
484 	/* Create the aiodone daemon kernel thread. */
485 	if (kthread_create1(uvm_aiodone_daemon, NULL, NULL, "aiodoned"))
486 		panic("fork aiodoned");
487 
488 #if defined(MULTIPROCESSOR)
489 	/* Boot the secondary processors. */
490 	cpu_boot_secondary_processors();
491 #endif
492 
493 	/* Initialize exec structures */
494 	exec_init(1);
495 
496 #ifdef NEW_PIPE
497 	/* Initialize pipe structures */
498 	pipe_init();
499 #endif
500 
501 	/*
502 	 * Okay, now we can let init(8) exec!  It's off to userland!
503 	 */
504 	start_init_exec = 1;
505 	wakeup((void *)&start_init_exec);
506 
507 #ifdef NVNODE_IMPLICIT
508 	/*
509 	 * If maximum number of vnodes in namei vnode cache is not explicitly
510 	 * defined in kernel config, adjust the number such as we use roughly
511 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
512 	 */
513 	usevnodes = (ptoa(physmem) / 200) / sizeof(struct vnode);
514 	if (usevnodes > desiredvnodes)
515 		desiredvnodes = usevnodes;
516 #endif
517 
518 	/* The scheduler is an infinite loop. */
519 	uvm_scheduler();
520 	/* NOTREACHED */
521 }
522 
523 static void
524 check_console(struct proc *p)
525 {
526 	struct nameidata nd;
527 	int error;
528 
529 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
530 	error = namei(&nd);
531 	if (error == 0)
532 		vrele(nd.ni_vp);
533 	else if (error == ENOENT)
534 		printf("warning: no /dev/console\n");
535 	else
536 		printf("warning: lookup /dev/console: error %d\n", error);
537 }
538 
539 /*
540  * List of paths to try when searching for "init".
541  */
542 static const char *initpaths[] = {
543 	"/sbin/init",
544 	"/sbin/oinit",
545 	"/sbin/init.bak",
546 	NULL,
547 };
548 
549 /*
550  * Start the initial user process; try exec'ing each pathname in "initpaths".
551  * The program is invoked with one argument containing the boot flags.
552  */
553 static void
554 start_init(void *arg)
555 {
556 	struct proc *p = arg;
557 	vaddr_t addr;
558 	struct sys_execve_args /* {
559 		syscallarg(const char *) path;
560 		syscallarg(char * const *) argp;
561 		syscallarg(char * const *) envp;
562 	} */ args;
563 	int options, i, error;
564 	register_t retval[2];
565 	char flags[4], *flagsp;
566 	const char **pathp, *path, *slash;
567 	char *ucp, **uap, *arg0, *arg1 = NULL;
568 
569 	/*
570 	 * Now in process 1.
571 	 */
572 	strncpy(p->p_comm, "init", MAXCOMLEN);
573 
574 	/*
575 	 * Wait for main() to tell us that it's safe to exec.
576 	 */
577 	while (start_init_exec == 0)
578 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
579 
580 	/*
581 	 * This is not the right way to do this.  We really should
582 	 * hand-craft a descriptor onto /dev/console to hand to init,
583 	 * but that's a _lot_ more work, and the benefit from this easy
584 	 * hack makes up for the "good is the enemy of the best" effect.
585 	 */
586 	check_console(p);
587 
588 	/*
589 	 * Need just enough stack to hold the faked-up "execve()" arguments.
590 	 */
591 	addr = USRSTACK - PAGE_SIZE;
592 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
593                     NULL, UVM_UNKNOWN_OFFSET, 0,
594                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
595 		    UVM_ADV_NORMAL,
596                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
597 		panic("init: couldn't allocate argument space");
598 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
599 
600 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
601 		ucp = (char *)(addr + PAGE_SIZE);
602 
603 		/*
604 		 * Construct the boot flag argument.
605 		 */
606 		flagsp = flags;
607 		*flagsp++ = '-';
608 		options = 0;
609 
610 		if (boothowto & RB_SINGLE) {
611 			*flagsp++ = 's';
612 			options = 1;
613 		}
614 #ifdef notyet
615 		if (boothowto & RB_FASTBOOT) {
616 			*flagsp++ = 'f';
617 			options = 1;
618 		}
619 #endif
620 
621 		/*
622 		 * Move out the flags (arg 1), if necessary.
623 		 */
624 		if (options != 0) {
625 			*flagsp++ = '\0';
626 			i = flagsp - flags;
627 #ifdef DEBUG
628 			printf("init: copying out flags `%s' %d\n", flags, i);
629 #endif
630 			(void)copyout((caddr_t)flags, (caddr_t)(ucp -= i), i);
631 			arg1 = ucp;
632 		}
633 
634 		/*
635 		 * Move out the file name (also arg 0).
636 		 */
637 		i = strlen(path) + 1;
638 #ifdef DEBUG
639 		printf("init: copying out path `%s' %d\n", path, i);
640 #endif
641 		(void)copyout((caddr_t)path, (caddr_t)(ucp -= i), i);
642 		arg0 = ucp;
643 
644 		/*
645 		 * Move out the arg pointers.
646 		 */
647 		uap = (char **)((long)ucp & ~ALIGNBYTES);
648 		(void)suword((caddr_t)--uap, 0);	/* terminator */
649 		if (options != 0)
650 			(void)suword((caddr_t)--uap, (long)arg1);
651 		slash = strrchr(path, '/');
652 		if (slash)
653 			(void)suword((caddr_t)--uap,
654 			    (long)arg0 + (slash + 1 - path));
655 		else
656 			(void)suword((caddr_t)--uap, (long)arg0);
657 
658 		/*
659 		 * Point at the arguments.
660 		 */
661 		SCARG(&args, path) = arg0;
662 		SCARG(&args, argp) = uap;
663 		SCARG(&args, envp) = NULL;
664 
665 		/*
666 		 * Now try to exec the program.  If can't for any reason
667 		 * other than it doesn't exist, complain.
668 		 */
669 		error = sys_execve(p, &args, retval);
670 		if (error == 0 || error == EJUSTRETURN) {
671 			KERNEL_PROC_UNLOCK(p);
672 			return;
673 		}
674 		if (error != ENOENT)
675 			printf("exec %s: error %d\n", path, error);
676 	}
677 	printf("init: not found\n");
678 	panic("no init");
679 }
680