xref: /freebsd/sys/kern/init_main.c (revision 3905c09afba02f5e86844bcbf9f8b52b960a5cd3)
1 /*
2  * Copyright (c) 1995 Terrence R. Lambert
3  * All rights reserved.
4  *
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	8.9 (Berkeley) 1/21/94
42  * $Id: init_main.c,v 1.5 1997/08/15 02:13:31 smp Exp smp $
43  */
44 
45 #include "opt_rlimit.h"
46 #include "opt_devfs.h"
47 
48 #include <sys/param.h>
49 #include <sys/file.h>
50 #include <sys/filedesc.h>
51 #include <sys/kernel.h>
52 #include <sys/mount.h>
53 #include <sys/sysctl.h>
54 #include <sys/proc.h>
55 #include <sys/resourcevar.h>
56 #include <sys/signalvar.h>
57 #include <sys/systm.h>
58 #include <sys/vnode.h>
59 #include <sys/sysent.h>
60 #include <sys/reboot.h>
61 #include <sys/sysproto.h>
62 #include <sys/vmmeter.h>
63 
64 #include <machine/cpu.h>
65 #ifdef SMP
66 #include <machine/smp.h>
67 #endif /* SMP */
68 
69 #include <vm/vm.h>
70 #include <vm/vm_param.h>
71 #include <vm/vm_prot.h>
72 #include <sys/lock.h>
73 #include <vm/pmap.h>
74 #include <vm/vm_map.h>
75 #include <sys/user.h>
76 #include <sys/copyright.h>
77 
78 extern struct linker_set	sysinit_set;	/* XXX */
79 
80 extern void __main __P((void));
81 extern void main __P((void *framep));
82 extern void secondary_main __P((void));
83 
84 /* Components of the first process -- never freed. */
85 static struct session session0;
86 static struct pgrp pgrp0;
87 struct	proc proc0;
88 static struct pcred cred0;
89 static struct filedesc0 filedesc0;
90 static struct plimit limit0;
91 static struct vmspace vmspace0;
92 #ifndef SMP	/* per-cpu on smp */
93 struct	proc *curproc = &proc0;
94 #endif
95 struct	proc *initproc;
96 
97 int cmask = CMASK;
98 extern	struct user *proc0paddr;
99 
100 struct	vnode *rootvp;
101 int	boothowto;
102 
103 struct	timeval boottime;
104 SYSCTL_STRUCT(_kern, KERN_BOOTTIME, boottime,
105 	CTLFLAG_RW, &boottime, timeval, "");
106 
107 static int shutdowntimeout = 120;
108 SYSCTL_INT(_kern, OID_AUTO, shutdown_timeout,
109 	CTLFLAG_RW, &shutdowntimeout, 0, "");
110 
111 #ifndef SMP	/* per-cpu on smp */
112 struct	timeval runtime;
113 #endif
114 
115 /*
116  * Promiscuous argument pass for start_init()
117  *
118  * This is a kludge because we use a return from main() rather than a call
119  * to a new routine in locore.s to kick the kernel alive from locore.s.
120  */
121 static void	*init_framep;
122 
123 
124 #if __GNUC__ >= 2
125 void __main() {}
126 #endif
127 
128 
129 /*
130  * This ensures that there is at least one entry so that the sysinit_set
131  * symbol is not undefined.  A sybsystem ID of SI_SUB_DUMMY is never
132  * executed.
133  */
134 SYSINIT(placeholder, SI_SUB_DUMMY,SI_ORDER_ANY, NULL, NULL)
135 
136 
137 /*
138  * System startup; initialize the world, create process 0, mount root
139  * filesystem, and fork to create init and pagedaemon.  Most of the
140  * hard work is done in the lower-level initialization routines including
141  * startup(), which does memory initialization and autoconfiguration.
142  *
143  * This allows simple addition of new kernel subsystems that require
144  * boot time initialization.  It also allows substitution of subsystem
145  * (for instance, a scheduler, kernel profiler, or VM system) by object
146  * module.  Finally, it allows for optional "kernel threads", like an LFS
147  * cleaner.
148  */
149 void
150 main(framep)
151 	void *framep;
152 {
153 
154 	register struct sysinit **sipp;		/* system initialization*/
155 	register struct sysinit **xipp;		/* interior loop of sort*/
156 	register struct sysinit *save;		/* bubble*/
157 	int			rval[2];	/* SI_TYPE_KTHREAD support*/
158 
159 	/*
160 	 * Copy the locore.s frame pointer for proc0, this is forked into
161 	 * all other processes.
162 	 */
163 	init_framep = framep;
164 
165 #ifdef SMP
166 	/*
167 	 * XXX curproc is per-cpu in SMP, and exists in freshly mapped pages,
168 	 * so its value must be initialized now before it is used by various
169 	 * initialization routines.  proc0_init() isn't soon enough:
170 	 * among other things, configure() is called first, and may call
171 	 * setdumpdev(), which panics without a valid curproc.
172 	 */
173 	curproc = &proc0;
174 #endif /* SMP */
175 
176 	/*
177 	 * Perform a bubble sort of the system initialization objects by
178 	 * their subsystem (primary key) and order (secondary key).
179 	 *
180 	 * Since some things care about execution order, this is the
181 	 * operation which ensures continued function.
182 	 */
183 	for( sipp = (struct sysinit **)sysinit_set.ls_items; *sipp; sipp++) {
184 		for( xipp = sipp + 1; *xipp; xipp++) {
185 			if( (*sipp)->subsystem < (*xipp)->subsystem ||
186 			    ( (*sipp)->subsystem == (*xipp)->subsystem &&
187 			      (*sipp)->order < (*xipp)->order))
188 				continue;	/* skip*/
189 			save = *sipp;
190 			*sipp = *xipp;
191 			*xipp = save;
192 		}
193 	}
194 
195 	/*
196 	 * Traverse the (now) ordered list of system initialization tasks.
197 	 * Perform each task, and continue on to the next task.
198 	 *
199 	 * The last item on the list is expected to be the scheduler,
200 	 * which will not return.
201 	 */
202 	for( sipp = (struct sysinit **)sysinit_set.ls_items; *sipp; sipp++) {
203 		if( (*sipp)->subsystem == SI_SUB_DUMMY)
204 			continue;	/* skip dummy task(s)*/
205 
206 		switch( (*sipp)->type) {
207 		case SI_TYPE_DEFAULT:
208 			/* no special processing*/
209 			(*((*sipp)->func))( (*sipp)->udata);
210 			break;
211 
212 		case SI_TYPE_KTHREAD:
213 			/* kernel thread*/
214 			if (fork(&proc0, NULL, rval))
215 				panic("fork kernel process");
216 			cpu_set_fork_handler(pfind(rval[0]), (*sipp)->func, (*sipp)->udata);
217 			break;
218 
219 		default:
220 			panic( "init_main: unrecognized init type");
221 		}
222 	}
223 
224 	panic("Shouldn't get here!");
225 	/* NOTREACHED*/
226 }
227 
228 
229 /*
230  * Start a kernel process.  This is called after a fork() call in
231  * main() in the file kern/init_main.c.
232  *
233  * This function is used to start "internal" daemons.
234  */
235 /* ARGSUSED*/
236 void
237 kproc_start(udata)
238 	void *udata;
239 {
240 	struct kproc_desc	*kp = udata;
241 	struct proc		*p = curproc;
242 
243 #ifdef DIAGNOSTIC
244 	printf("Start pid=%d <%s>\n",p->p_pid, kp->arg0);
245 #endif
246 
247 
248 	/* save a global descriptor, if desired*/
249 	if( kp->global_procpp != NULL)
250 		*kp->global_procpp	= p;
251 
252 	/* this is a non-swapped system process*/
253 	p->p_flag |= P_INMEM | P_SYSTEM;
254 
255 	/* set up arg0 for 'ps', et al*/
256 	strcpy( p->p_comm, kp->arg0);
257 
258 	/* call the processes' main()...*/
259 	(*kp->func)();
260 
261 	/* NOTREACHED */
262 	panic("kproc_start: %s", kp->arg0);
263 }
264 
265 
266 /*
267  ***************************************************************************
268  ****
269  **** The following SYSINIT's belong elsewhere, but have not yet
270  **** been moved.
271  ****
272  ***************************************************************************
273  */
274 #ifdef OMIT
275 /*
276  * Handled by vfs_mountroot (bad idea) at this time... should be
277  * done the same as 4.4Lite2.
278  */
279 SYSINIT(swapinit, SI_SUB_SWAP, SI_ORDER_FIRST, swapinit, NULL)
280 #endif	/* OMIT*/
281 
282 static void print_caddr_t __P((void *data));
283 static void
284 print_caddr_t(data)
285 	void *data;
286 {
287 	printf("%s", (char *)data);
288 }
289 SYSINIT(announce, SI_SUB_COPYRIGHT, SI_ORDER_FIRST, print_caddr_t, copyright)
290 
291 
292 /*
293  ***************************************************************************
294  ****
295  **** The two following SYSINT's are proc0 specific glue code.  I am not
296  **** convinced that they can not be safely combined, but their order of
297  **** operation has been maintained as the same as the original init_main.c
298  **** for right now.
299  ****
300  **** These probably belong in init_proc.c or kern_proc.c, since they
301  **** deal with proc0 (the fork template process).
302  ****
303  ***************************************************************************
304  */
305 /* ARGSUSED*/
306 static void proc0_init __P((void *dummy));
307 static void
308 proc0_init(dummy)
309 	void *dummy;
310 {
311 	register struct proc		*p;
312 	register struct filedesc0	*fdp;
313 	register unsigned i;
314 
315 	/*
316 	 * Initialize the current process pointer (curproc) before
317 	 * any possible traps/probes to simplify trap processing.
318 	 */
319 	p = &proc0;
320 	curproc = p;			/* XXX redundant*/
321 
322 	/*
323 	 * Initialize process and pgrp structures.
324 	 */
325 	procinit();
326 
327 	/*
328 	 * Initialize sleep queue hash table
329 	 */
330 	sleepinit();
331 
332 	/*
333 	 * additional VM structures
334 	 */
335 	vm_init2();
336 
337 	/*
338 	 * Create process 0 (the swapper).
339 	 */
340 	LIST_INSERT_HEAD(&allproc, p, p_list);
341 	p->p_pgrp = &pgrp0;
342 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
343 	LIST_INIT(&pgrp0.pg_members);
344 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
345 
346 	pgrp0.pg_session = &session0;
347 	session0.s_count = 1;
348 	session0.s_leader = p;
349 
350 	p->p_sysent = &aout_sysvec;
351 
352 	p->p_flag = P_INMEM | P_SYSTEM;
353 	p->p_stat = SRUN;
354 	p->p_nice = NZERO;
355 	p->p_rtprio.type = RTP_PRIO_NORMAL;
356 	p->p_rtprio.prio = 0;
357 
358 /*
359  * Link for kernel based threads
360  */
361 	p->p_peers = 0;
362 	p->p_leader = p;
363 
364 	bcopy("swapper", p->p_comm, sizeof ("swapper"));
365 
366 	/* Create credentials. */
367 	cred0.p_refcnt = 1;
368 	p->p_cred = &cred0;
369 	p->p_ucred = crget();
370 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
371 
372 	/* Create the file descriptor table. */
373 	fdp = &filedesc0;
374 	p->p_fd = &fdp->fd_fd;
375 	fdp->fd_fd.fd_refcnt = 1;
376 	fdp->fd_fd.fd_cmask = cmask;
377 	fdp->fd_fd.fd_ofiles = fdp->fd_dfiles;
378 	fdp->fd_fd.fd_ofileflags = fdp->fd_dfileflags;
379 	fdp->fd_fd.fd_nfiles = NDFILE;
380 
381 	/* Create the limits structures. */
382 	p->p_limit = &limit0;
383 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
384 		limit0.pl_rlimit[i].rlim_cur =
385 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
386 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
387 	    limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
388 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
389 	    limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
390 	i = ptoa(cnt.v_free_count);
391 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = i;
392 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = i;
393 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = i / 3;
394 	limit0.p_refcnt = 1;
395 
396 	/* Allocate a prototype map so we have something to fork. */
397 	p->p_vmspace = &vmspace0;
398 	vmspace0.vm_refcnt = 1;
399 	pmap_pinit(&vmspace0.vm_pmap);
400 	vm_map_init(&vmspace0.vm_map, round_page(VM_MIN_ADDRESS),
401 	    trunc_page(VM_MAXUSER_ADDRESS), TRUE);
402 	vmspace0.vm_map.pmap = &vmspace0.vm_pmap;
403 	p->p_addr = proc0paddr;				/* XXX */
404 
405 #define INCOMPAT_LITES2
406 #ifdef INCOMPAT_LITES2
407 	/*
408 	 * proc0 needs to have a coherent frame base in it's stack.
409 	 */
410 	cpu_set_init_frame(p, init_framep);			/* XXX! */
411 #endif	/* INCOMPAT_LITES2*/
412 
413 	/*
414 	 * We continue to place resource usage info and signal
415 	 * actions in the user struct so they're pageable.
416 	 */
417 	p->p_stats = &p->p_addr->u_stats;
418 	p->p_sigacts = &p->p_addr->u_sigacts;
419 
420 	/*
421 	 * Charge root for one process.
422 	 */
423 	(void)chgproccnt(0, 1);
424 }
425 SYSINIT(p0init, SI_SUB_INTRINSIC, SI_ORDER_FIRST, proc0_init, NULL)
426 
427 /* ARGSUSED*/
428 static void proc0_post __P((void *dummy));
429 static void
430 proc0_post(dummy)
431 	void *dummy;
432 {
433 	struct timeval tv;
434 
435 	/*
436 	 * Now can look at time, having had a chance to verify the time
437 	 * from the file system.  Reset p->p_rtime as it may have been
438 	 * munched in mi_switch() after the time got set.
439 	 */
440 	gettime(&boottime);
441 	proc0.p_stats->p_start = runtime = mono_time = boottime;
442 	proc0.p_rtime.tv_sec = proc0.p_rtime.tv_usec = 0;
443 
444 	/*
445 	 * Give the ``random'' number generator a thump.
446 	 */
447 	microtime(&tv);
448 	srandom(tv.tv_sec ^ tv.tv_usec);
449 
450 	/* Initialize signal state for process 0. */
451 	siginit(&proc0);
452 }
453 SYSINIT(p0post, SI_SUB_INTRINSIC_POST, SI_ORDER_FIRST, proc0_post, NULL)
454 
455 
456 
457 
458 /*
459  ***************************************************************************
460  ****
461  **** The following SYSINIT's and glue code should be moved to the
462  **** respective files on a per subsystem basis.
463  ****
464  ***************************************************************************
465  */
466 /* ARGSUSED*/
467 static void sched_setup __P((void *dummy));
468 static void
469 sched_setup(dummy)
470 	void *dummy;
471 {
472 	/* Kick off timeout driven events by calling first time. */
473 	roundrobin(NULL);
474 	schedcpu(NULL);
475 }
476 SYSINIT(sched_setup, SI_SUB_KICK_SCHEDULER, SI_ORDER_FIRST, sched_setup, NULL)
477 
478 /* ARGSUSED*/
479 static void xxx_vfs_mountroot __P((void *fsnamep));
480 #ifdef BOOTP
481 extern void bootpc_init __P((void));
482 #endif
483 static void
484 xxx_vfs_mountroot(fsnamep)
485 	void *fsnamep;
486 {
487   /* XXX Add a separate SYSINIT entry */
488 #ifdef BOOTP
489 	bootpc_init();
490 #endif
491 	/* Mount the root file system. */
492 	if (vfs_mountrootfs(*((char **) fsnamep)))
493 		panic("cannot mount root");
494 }
495 SYSINIT(mountroot, SI_SUB_ROOT, SI_ORDER_FIRST, xxx_vfs_mountroot, &mountrootfsname)
496 
497 /* ARGSUSED*/
498 static void xxx_vfs_root_fdtab __P((void *dummy));
499 static void
500 xxx_vfs_root_fdtab(dummy)
501 	void *dummy;
502 {
503 	register struct filedesc0	*fdp = &filedesc0;
504 
505 	/* Get the vnode for '/'.  Set fdp->fd_fd.fd_cdir to reference it. */
506 	if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
507 		panic("cannot find root vnode");
508 	fdp->fd_fd.fd_cdir = rootvnode;
509 	VREF(fdp->fd_fd.fd_cdir);
510 	VOP_UNLOCK(rootvnode, 0, &proc0);
511 	fdp->fd_fd.fd_rdir = NULL;
512 }
513 SYSINIT(retrofit, SI_SUB_ROOT_FDTAB, SI_ORDER_FIRST, xxx_vfs_root_fdtab, NULL)
514 
515 
516 /*
517  ***************************************************************************
518  ****
519  **** The following code probably belongs in another file, like
520  **** kern/init_init.c.  It is here for two reasons only:
521  ****
522  ****	1)	This code returns to startup the system; this is
523  ****		abnormal for a kernel thread.
524  ****	2)	This code promiscuously uses init_frame
525  ****
526  ***************************************************************************
527  */
528 
529 static void kthread_init __P((void *dummy));
530 SYSINIT_KT(init,SI_SUB_KTHREAD_INIT, SI_ORDER_FIRST, kthread_init, NULL)
531 
532 
533 extern void prepare_usermode __P((void));
534 static void start_init __P((struct proc *p));
535 
536 /* ARGSUSED*/
537 static void
538 kthread_init(dummy)
539 	void *dummy;
540 {
541 	/* Create process 1 (init(8)). */
542 	start_init(curproc);
543 
544 #ifdef SMP
545 	/* wait for the SMP idle loops to come online */
546 	while (smp_idle_loops < mp_ncpus)
547 		tsleep((caddr_t *)&smp_idle_loops, PWAIT, "smpilw", 0);
548 #endif /* SMP */
549 
550 	prepare_usermode();
551 
552 	/*
553 	 * This returns to the fork trampoline, then to user mode.
554 	 */
555 	return;
556 }
557 
558 
559 /*
560  * List of paths to try when searching for "init".
561  */
562 static char *initpaths[] = {
563 	"/sbin/init",
564 	"/sbin/oinit",
565 	"/sbin/init.bak",
566 	"/stand/sysinstall",
567 	NULL,
568 };
569 
570 /*
571  * Start the initial user process; try exec'ing each pathname in "initpaths".
572  * The program is invoked with one argument containing the boot flags.
573  */
574 static void
575 start_init(p)
576 	struct proc *p;
577 {
578 	vm_offset_t addr;
579 	struct execve_args args;
580 	int options, i, retval[2], error;
581 	char **pathp, *path, *ucp, **uap, *arg0, *arg1;
582 
583 	initproc = p;
584 
585 	/*
586 	 * Need just enough stack to hold the faked-up "execve()" arguments.
587 	 */
588 	addr = trunc_page(VM_MAXUSER_ADDRESS - PAGE_SIZE);
589 	if (vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr, PAGE_SIZE, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != 0)
590 		panic("init: couldn't allocate argument space");
591 	p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
592 	p->p_vmspace->vm_ssize = 1;
593 
594 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
595 		/*
596 		 * Move out the boot flag argument.
597 		 */
598 		options = 0;
599 		ucp = (char *)USRSTACK;
600 		(void)subyte(--ucp, 0);		/* trailing zero */
601 		if (boothowto & RB_SINGLE) {
602 			(void)subyte(--ucp, 's');
603 			options = 1;
604 		}
605 #ifdef notyet
606                 if (boothowto & RB_FASTBOOT) {
607 			(void)subyte(--ucp, 'f');
608 			options = 1;
609 		}
610 #endif
611 
612 #ifdef BOOTCDROM
613 		(void)subyte(--ucp, 'C');
614 		options = 1;
615 #endif
616 
617 #if defined(DEVFS) && defined(DEVFS_ROOT)
618 		(void)subyte(--ucp, 'd');
619 		options = 1;
620 #endif
621 		if (options == 0)
622 			(void)subyte(--ucp, '-');
623 		(void)subyte(--ucp, '-');		/* leading hyphen */
624 		arg1 = ucp;
625 
626 		/*
627 		 * Move out the file name (also arg 0).
628 		 */
629 		for (i = strlen(path) + 1; i >= 0; i--)
630 			(void)subyte(--ucp, path[i]);
631 		arg0 = ucp;
632 
633 		/*
634 		 * Move out the arg pointers.
635 		 */
636 		uap = (char **)((int)ucp & ~(NBPW-1));
637 		(void)suword((caddr_t)--uap, 0);	/* terminator */
638 		(void)suword((caddr_t)--uap, (int)arg1);
639 		(void)suword((caddr_t)--uap, (int)arg0);
640 
641 		/*
642 		 * Point at the arguments.
643 		 */
644 		args.fname = arg0;
645 		args.argv = uap;
646 		args.envv = NULL;
647 
648 		/*
649 		 * Now try to exec the program.  If can't for any reason
650 		 * other than it doesn't exist, complain.
651 		 *
652 		 * Otherwise return to main() which returns to btext
653 		 * which completes the system startup.
654 		 */
655 		if ((error = execve(p, &args, &retval[0])) == 0)
656 			return;
657 		if (error != ENOENT)
658 			printf("exec %s: error %d\n", path, error);
659 	}
660 	printf("init: not found\n");
661 	panic("no init");
662 }
663