xref: /netbsd-src/sys/kern/init_main.c (revision 17dd36da8292193180754d5047c0926dbb56818c)
1 /*	$NetBSD: init_main.c,v 1.189 2001/03/15 06:10:55 chs 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_syscall_debug.h"
50 
51 #include "rnd.h"
52 
53 #include <sys/param.h>
54 #include <sys/acct.h>
55 #include <sys/filedesc.h>
56 #include <sys/file.h>
57 #include <sys/errno.h>
58 #include <sys/callout.h>
59 #include <sys/kernel.h>
60 #include <sys/mount.h>
61 #include <sys/map.h>
62 #include <sys/proc.h>
63 #include <sys/kthread.h>
64 #include <sys/resourcevar.h>
65 #include <sys/signalvar.h>
66 #include <sys/systm.h>
67 #include <sys/vnode.h>
68 #include <sys/tty.h>
69 #include <sys/conf.h>
70 #include <sys/disklabel.h>
71 #include <sys/buf.h>
72 #include <sys/device.h>
73 #include <sys/exec.h>
74 #include <sys/socketvar.h>
75 #include <sys/protosw.h>
76 #include <sys/reboot.h>
77 #include <sys/user.h>
78 #include <sys/sysctl.h>
79 #ifdef SYSVSHM
80 #include <sys/shm.h>
81 #endif
82 #ifdef SYSVSEM
83 #include <sys/sem.h>
84 #endif
85 #ifdef SYSVMSG
86 #include <sys/msg.h>
87 #endif
88 #include <sys/domain.h>
89 #include <sys/mbuf.h>
90 #include <sys/namei.h>
91 #if NRND > 0
92 #include <sys/rnd.h>
93 #endif
94 
95 #include <sys/syscall.h>
96 #include <sys/syscallargs.h>
97 
98 #include <ufs/ufs/quota.h>
99 
100 #include <miscfs/genfs/genfs.h>
101 #include <miscfs/syncfs/syncfs.h>
102 
103 #include <machine/cpu.h>
104 
105 #include <uvm/uvm.h>
106 
107 #include <net/if.h>
108 #include <net/raw_cb.h>
109 
110 const char copyright[] = "\
111 Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001
112     The NetBSD Foundation, Inc.  All rights reserved.
113 Copyright (c) 1982, 1986, 1989, 1991, 1993
114     The Regents of the University of California.  All rights reserved.
115 
116 ";
117 
118 /* Components of the first process -- never freed. */
119 struct	session session0;
120 struct	pgrp pgrp0;
121 struct	proc proc0;
122 struct	pcred cred0;
123 struct	filedesc0 filedesc0;
124 struct	cwdinfo cwdi0;
125 struct	plimit limit0;
126 struct	vmspace vmspace0;
127 struct	sigacts sigacts0;
128 #ifndef curproc
129 struct	proc *curproc = &proc0;
130 #endif
131 struct	proc *initproc;
132 
133 int	cmask = CMASK;
134 extern	struct user *proc0paddr;
135 
136 struct	vnode *rootvp, *swapdev_vp;
137 int	boothowto;
138 int	cold = 1;			/* still working on startup */
139 struct	timeval boottime;
140 
141 __volatile int start_init_exec;		/* semaphore for start_init() */
142 
143 static void check_console(struct proc *p);
144 static void start_init(void *);
145 void main(void);
146 
147 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
148 
149 /*
150  * System startup; initialize the world, create process 0, mount root
151  * filesystem, and fork to create init and pagedaemon.  Most of the
152  * hard work is done in the lower-level initialization routines including
153  * startup(), which does memory initialization and autoconfiguration.
154  */
155 void
156 main(void)
157 {
158 	struct proc *p;
159 	struct pdevinit *pdev;
160 	int i, s, error;
161 	rlim_t lim;
162 	extern struct pdevinit pdevinit[];
163 	extern void schedcpu(void *);
164 	extern void disk_init(void);
165 #if defined(NFSSERVER) || defined(NFS)
166 	extern void nfs_init(void);
167 #endif
168 #ifdef NVNODE_IMPLICIT
169 	int usevnodes;
170 #endif
171 
172 	/*
173 	 * Initialize the current process pointer (curproc) before
174 	 * any possible traps/probes to simplify trap processing.
175 	 */
176 	p = &proc0;
177 	curproc = p;
178 	p->p_cpu = curcpu();
179 	/*
180 	 * Attempt to find console and initialize
181 	 * in case of early panic or other messages.
182 	 */
183 	consinit();
184 	printf("%s", copyright);
185 
186 	KERNEL_LOCK_INIT();
187 
188 	uvm_init();
189 
190 	/* Do machine-dependent initialization. */
191 	cpu_startup();
192 
193 	/* Initialize callouts. */
194 	callout_startup();
195 
196 	/*
197 	 * Initialize mbuf's.  Do this now because we might attempt to
198 	 * allocate mbufs or mbuf clusters during autoconfiguration.
199 	 */
200 	mbinit();
201 
202 	/* Initialize sockets. */
203 	soinit();
204 
205 	/*
206 	 * The following 3 things must be done before autoconfiguration.
207 	 */
208 	disk_init();		/* initialize disk list */
209 	tty_init();		/* initialize tty list */
210 #if NRND > 0
211 	rnd_init();		/* initialize RNG */
212 #endif
213 
214 	/* Initialize the sysctl subsystem. */
215 	sysctl_init();
216 
217 	/*
218 	 * Initialize process and pgrp structures.
219 	 */
220 	procinit();
221 
222 	/*
223 	 * Create process 0 (the swapper).
224 	 */
225 	s = proclist_lock_write();
226 	LIST_INSERT_HEAD(&allproc, p, p_list);
227 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
228 	proclist_unlock_write(s);
229 
230 	p->p_pgrp = &pgrp0;
231 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
232 	LIST_INIT(&pgrp0.pg_members);
233 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
234 
235 	pgrp0.pg_session = &session0;
236 	session0.s_count = 1;
237 	session0.s_sid = p->p_pid;
238 	session0.s_leader = p;
239 
240 	/*
241 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
242 	 * init(8) when they exit.  init(8) can easily wait them out
243 	 * for us.
244 	 */
245 	p->p_flag = P_INMEM | P_SYSTEM | P_NOCLDWAIT;
246 	p->p_stat = SONPROC;
247 	p->p_nice = NZERO;
248 	p->p_emul = &emul_netbsd;
249 #ifdef __HAVE_SYSCALL_INTERN
250 	(*p->p_emul->e_syscall_intern)(p);
251 #endif
252 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
253 
254 	callout_init(&p->p_realit_ch);
255 	callout_init(&p->p_tsleep_ch);
256 
257 	/* Create credentials. */
258 	cred0.p_refcnt = 1;
259 	p->p_cred = &cred0;
260 	p->p_ucred = crget();
261 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
262 
263 	/* Create the file descriptor table. */
264 	finit();
265 	p->p_fd = &filedesc0.fd_fd;
266 	fdinit1(&filedesc0);
267 
268 	/* Create the CWD info. */
269 	p->p_cwdi = &cwdi0;
270 	cwdi0.cwdi_cmask = cmask;
271 	cwdi0.cwdi_refcnt = 1;
272 
273 	/* Create the limits structures. */
274 	p->p_limit = &limit0;
275 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
276 		limit0.pl_rlimit[i].rlim_cur =
277 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
278 
279 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
280 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
281 	    maxfiles < NOFILE ? maxfiles : NOFILE;
282 
283 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
284 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
285 	    maxproc < MAXUPRC ? maxproc : MAXUPRC;
286 
287 	lim = ptoa(uvmexp.free);
288 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
289 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
290 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
291 	limit0.pl_corename = defcorename;
292 	limit0.p_refcnt = 1;
293 
294 	/*
295 	 * Initialize proc0's vmspace, which uses the kernel pmap.
296 	 * All kernel processes (which never have user space mappings)
297 	 * share proc0's vmspace, and thus, the kernel pmap.
298 	 */
299 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
300 	    trunc_page(VM_MAX_ADDRESS), TRUE);
301 	p->p_vmspace = &vmspace0;
302 
303 	p->p_addr = proc0paddr;				/* XXX */
304 
305 	/*
306 	 * We continue to place resource usage info in the
307 	 * user struct so they're pageable.
308 	 */
309 	p->p_stats = &p->p_addr->u_stats;
310 
311 	/*
312 	 * Charge root for one process.
313 	 */
314 	(void)chgproccnt(0, 1);
315 
316 	rqinit();
317 
318 	/* Configure virtual memory system, set vm rlimits. */
319 	uvm_init_limits(p);
320 
321 	/* Initialize the file systems. */
322 #if defined(NFSSERVER) || defined(NFS)
323 	nfs_init();			/* initialize server/shared data */
324 #endif
325 	vfsinit();
326 
327 	/* Configure the system hardware.  This will enable interrupts. */
328 	configure();
329 
330 	ubc_init();		/* must be after autoconfig */
331 
332 	/* Lock the kernel on behalf of proc0. */
333 	KERNEL_PROC_LOCK(p);
334 
335 #ifdef SYSVSHM
336 	/* Initialize System V style shared memory. */
337 	shminit();
338 #endif
339 
340 #ifdef SYSVSEM
341 	/* Initialize System V style semaphores. */
342 	seminit();
343 #endif
344 
345 #ifdef SYSVMSG
346 	/* Initialize System V style message queues. */
347 	msginit();
348 #endif
349 
350 	/* Attach pseudo-devices. */
351 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
352 		(*pdev->pdev_attach)(pdev->pdev_count);
353 
354 	/*
355 	 * Initialize protocols.  Block reception of incoming packets
356 	 * until everything is ready.
357 	 */
358 	s = splimp();
359 	ifinit();
360 	domaininit();
361 	splx(s);
362 
363 #ifdef GPROF
364 	/* Initialize kernel profiling. */
365 	kmstartup();
366 #endif
367 
368 	/* Initialize system accouting. */
369 	acct_init();
370 
371 	/*
372 	 * Initialize signal-related data structures, and signal state
373 	 * for proc0.
374 	 */
375 	signal_init();
376 	p->p_sigacts = &sigacts0;
377 	siginit(p);
378 
379 	/* Kick off timeout driven events by calling first time. */
380 	schedcpu(NULL);
381 
382 	/*
383 	 * Create process 1 (init(8)).  We do this now, as Unix has
384 	 * historically had init be process 1, and changing this would
385 	 * probably upset a lot of people.
386 	 *
387 	 * Note that process 1 won't immediately exec init(8), but will
388 	 * wait for us to inform it that the root file system has been
389 	 * mounted.
390 	 */
391 	if (fork1(p, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
392 		panic("fork init");
393 
394 	/*
395 	 * Create any kernel threads who's creation was deferred because
396 	 * initproc had not yet been created.
397 	 */
398 	kthread_run_deferred_queue();
399 
400 	/*
401 	 * Now that device driver threads have been created, wait for
402 	 * them to finish any deferred autoconfiguration.  Note we don't
403 	 * need to lock this semaphore, since we haven't booted any
404 	 * secondary processors, yet.
405 	 */
406 	while (config_pending)
407 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
408 
409 	/*
410 	 * Now that autoconfiguration has completed, we can determine
411 	 * the root and dump devices.
412 	 */
413 	cpu_rootconf();
414 	cpu_dumpconf();
415 
416 	/* Mount the root file system. */
417 	do {
418 		domountroothook();
419 		if ((error = vfs_mountroot())) {
420 			printf("cannot mount root, error = %d\n", error);
421 			boothowto |= RB_ASKNAME;
422 			setroot(root_device,
423 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
424 		}
425 	} while (error != 0);
426 	mountroothook_destroy();
427 
428 	mountlist.cqh_first->mnt_flag |= MNT_ROOTFS;
429 	mountlist.cqh_first->mnt_op->vfs_refcount++;
430 
431 	/*
432 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
433 	 * reference it.
434 	 */
435 	if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
436 		panic("cannot find root vnode");
437 	cwdi0.cwdi_cdir = rootvnode;
438 	VREF(cwdi0.cwdi_cdir);
439 	VOP_UNLOCK(rootvnode, 0);
440 	cwdi0.cwdi_rdir = NULL;
441 
442 	/*
443 	 * Now that root is mounted, we can fixup initproc's CWD
444 	 * info.  All other processes are kthreads, which merely
445 	 * share proc0's CWD info.
446 	 */
447 	initproc->p_cwdi->cwdi_cdir = rootvnode;
448 	VREF(initproc->p_cwdi->cwdi_cdir);
449 	initproc->p_cwdi->cwdi_rdir = NULL;
450 
451 	/*
452 	 * Now can look at time, having had a chance to verify the time
453 	 * from the file system.  Reset p->p_rtime as it may have been
454 	 * munched in mi_switch() after the time got set.
455 	 */
456 	proclist_lock_read();
457 	s = splsched();
458 	for (p = LIST_FIRST(&allproc); p != NULL;
459 	     p = LIST_NEXT(p, p_list)) {
460 		p->p_stats->p_start = mono_time = boottime = time;
461 		if (p->p_cpu != NULL)
462 			p->p_cpu->ci_schedstate.spc_runtime = time;
463 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
464 	}
465 	splx(s);
466 	proclist_unlock_read();
467 
468 	/* Create the pageout daemon kernel thread. */
469 	uvm_swap_init();
470 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
471 		panic("fork pagedaemon");
472 
473 	/* Create the process reaper kernel thread. */
474 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
475 		panic("fork reaper");
476 
477 	/* Create the filesystem syncer kernel thread. */
478 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
479 		panic("fork syncer");
480 
481 	/* Create the aiodone daemon kernel thread. */
482 	if (kthread_create1(uvm_aiodone_daemon, NULL, NULL, "aiodoned"))
483 		panic("fork aiodoned");
484 
485 #if defined(MULTIPROCESSOR)
486 	/* Boot the secondary processors. */
487 	cpu_boot_secondary_processors();
488 #endif
489 
490 	/* Initialize exec structures */
491 	exec_init(1);
492 
493 	/*
494 	 * Okay, now we can let init(8) exec!  It's off to userland!
495 	 */
496 	start_init_exec = 1;
497 	wakeup((void *)&start_init_exec);
498 
499 #ifdef NVNODE_IMPLICIT
500 	/*
501 	 * If maximum number of vnodes in namei vnode cache is not explicitly
502 	 * defined in kernel config, adjust the number such as we use roughly
503 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
504 	 */
505 	usevnodes = (ptoa(physmem) / 200) / sizeof(struct vnode);
506 	if (usevnodes > desiredvnodes)
507 		desiredvnodes = usevnodes;
508 #endif
509 
510 	/* The scheduler is an infinite loop. */
511 	uvm_scheduler();
512 	/* NOTREACHED */
513 }
514 
515 static void
516 check_console(struct proc *p)
517 {
518 	struct nameidata nd;
519 	int error;
520 
521 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
522 	error = namei(&nd);
523 	if (error == 0)
524 		vrele(nd.ni_vp);
525 	else if (error == ENOENT)
526 		printf("warning: no /dev/console\n");
527 	else
528 		printf("warning: lookup /dev/console: error %d\n", error);
529 }
530 
531 /*
532  * List of paths to try when searching for "init".
533  */
534 static const char *initpaths[] = {
535 	"/sbin/init",
536 	"/sbin/oinit",
537 	"/sbin/init.bak",
538 	NULL,
539 };
540 
541 /*
542  * Start the initial user process; try exec'ing each pathname in "initpaths".
543  * The program is invoked with one argument containing the boot flags.
544  */
545 static void
546 start_init(void *arg)
547 {
548 	struct proc *p = arg;
549 	vaddr_t addr;
550 	struct sys_execve_args /* {
551 		syscallarg(const char *) path;
552 		syscallarg(char * const *) argp;
553 		syscallarg(char * const *) envp;
554 	} */ args;
555 	int options, i, error;
556 	register_t retval[2];
557 	char flags[4], *flagsp;
558 	const char **pathp, *path, *slash;
559 	char *ucp, **uap, *arg0, *arg1 = NULL;
560 
561 	/*
562 	 * Now in process 1.
563 	 */
564 	strncpy(p->p_comm, "init", MAXCOMLEN);
565 
566 	/*
567 	 * Wait for main() to tell us that it's safe to exec.
568 	 */
569 	while (start_init_exec == 0)
570 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
571 
572 	/*
573 	 * This is not the right way to do this.  We really should
574 	 * hand-craft a descriptor onto /dev/console to hand to init,
575 	 * but that's a _lot_ more work, and the benefit from this easy
576 	 * hack makes up for the "good is the enemy of the best" effect.
577 	 */
578 	check_console(p);
579 
580 	/*
581 	 * Need just enough stack to hold the faked-up "execve()" arguments.
582 	 */
583 	addr = USRSTACK - PAGE_SIZE;
584 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
585                     NULL, UVM_UNKNOWN_OFFSET, 0,
586                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
587 		    UVM_ADV_NORMAL,
588                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
589 		panic("init: couldn't allocate argument space");
590 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
591 
592 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
593 		ucp = (char *)(addr + PAGE_SIZE);
594 
595 		/*
596 		 * Construct the boot flag argument.
597 		 */
598 		flagsp = flags;
599 		*flagsp++ = '-';
600 		options = 0;
601 
602 		if (boothowto & RB_SINGLE) {
603 			*flagsp++ = 's';
604 			options = 1;
605 		}
606 #ifdef notyet
607 		if (boothowto & RB_FASTBOOT) {
608 			*flagsp++ = 'f';
609 			options = 1;
610 		}
611 #endif
612 
613 		/*
614 		 * Move out the flags (arg 1), if necessary.
615 		 */
616 		if (options != 0) {
617 			*flagsp++ = '\0';
618 			i = flagsp - flags;
619 #ifdef DEBUG
620 			printf("init: copying out flags `%s' %d\n", flags, i);
621 #endif
622 			(void)copyout((caddr_t)flags, (caddr_t)(ucp -= i), i);
623 			arg1 = ucp;
624 		}
625 
626 		/*
627 		 * Move out the file name (also arg 0).
628 		 */
629 		i = strlen(path) + 1;
630 #ifdef DEBUG
631 		printf("init: copying out path `%s' %d\n", path, i);
632 #endif
633 		(void)copyout((caddr_t)path, (caddr_t)(ucp -= i), i);
634 		arg0 = ucp;
635 
636 		/*
637 		 * Move out the arg pointers.
638 		 */
639 		uap = (char **)((long)ucp & ~ALIGNBYTES);
640 		(void)suword((caddr_t)--uap, 0);	/* terminator */
641 		if (options != 0)
642 			(void)suword((caddr_t)--uap, (long)arg1);
643 		slash = strrchr(path, '/');
644 		if (slash)
645 			(void)suword((caddr_t)--uap,
646 			    (long)arg0 + (slash + 1 - path));
647 		else
648 			(void)suword((caddr_t)--uap, (long)arg0);
649 
650 		/*
651 		 * Point at the arguments.
652 		 */
653 		SCARG(&args, path) = arg0;
654 		SCARG(&args, argp) = uap;
655 		SCARG(&args, envp) = NULL;
656 
657 		/*
658 		 * Now try to exec the program.  If can't for any reason
659 		 * other than it doesn't exist, complain.
660 		 */
661 		error = sys_execve(p, &args, retval);
662 		if (error == 0 || error == EJUSTRETURN) {
663 			KERNEL_PROC_UNLOCK(p);
664 			return;
665 		}
666 		if (error != ENOENT)
667 			printf("exec %s: error %d\n", path, error);
668 	}
669 	printf("init: not found\n");
670 	panic("no init");
671 }
672