xref: /netbsd-src/sys/kern/init_main.c (revision a93ea220fcb3e34cdfdcd4d7a5d391e0b2b4f2ba)
1 /*	$NetBSD: init_main.c,v 1.222 2003/07/30 18:45:32 jonathan 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 1.222 2003/07/30 18:45:32 jonathan 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_pipe.h"
53 #include "opt_syscall_debug.h"
54 #include "opt_systrace.h"
55 #include "opt_posix.h"
56 
57 #include "opencrypto.h"
58 #include "rnd.h"
59 
60 #include <sys/param.h>
61 #include <sys/acct.h>
62 #include <sys/filedesc.h>
63 #include <sys/file.h>
64 #include <sys/errno.h>
65 #include <sys/callout.h>
66 #include <sys/kernel.h>
67 #include <sys/mount.h>
68 #include <sys/proc.h>
69 #include <sys/kthread.h>
70 #include <sys/resourcevar.h>
71 #include <sys/signalvar.h>
72 #include <sys/systm.h>
73 #include <sys/vnode.h>
74 #include <sys/tty.h>
75 #include <sys/conf.h>
76 #include <sys/disklabel.h>
77 #include <sys/buf.h>
78 #include <sys/device.h>
79 #include <sys/disk.h>
80 #include <sys/exec.h>
81 #include <sys/socketvar.h>
82 #include <sys/protosw.h>
83 #include <sys/reboot.h>
84 #include <sys/user.h>
85 #include <sys/sysctl.h>
86 #include <sys/event.h>
87 #ifdef SYSVSHM
88 #include <sys/shm.h>
89 #endif
90 #ifdef SYSVSEM
91 #include <sys/sem.h>
92 #endif
93 #ifdef SYSVMSG
94 #include <sys/msg.h>
95 #endif
96 #ifdef P1003_1B_SEMAPHORE
97 #include <sys/ksem.h>
98 #endif
99 #ifdef SYSTRACE
100 #include <sys/systrace.h>
101 #endif
102 #include <sys/domain.h>
103 #include <sys/mbuf.h>
104 #include <sys/namei.h>
105 #if NOPENCRYPTO > 0
106 #include <opencrypto/cryptodev.h>	/* XXX really  the framework */
107 #endif
108 #if NRND > 0
109 #include <sys/rnd.h>
110 #endif
111 #ifndef PIPE_SOCKETPAIR
112 #include <sys/pipe.h>
113 #endif
114 #ifdef LKM
115 #include <sys/lkm.h>
116 #endif
117 
118 #include <sys/syscall.h>
119 #include <sys/sa.h>
120 #include <sys/syscallargs.h>
121 
122 #include <ufs/ufs/quota.h>
123 
124 #include <miscfs/genfs/genfs.h>
125 #include <miscfs/syncfs/syncfs.h>
126 
127 #include <machine/cpu.h>
128 
129 #include <uvm/uvm.h>
130 
131 #include <dev/cons.h>
132 
133 #include <net/if.h>
134 #include <net/raw_cb.h>
135 
136 const char copyright[] =
137 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003\n"
138 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
139 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
140 "    The Regents of the University of California.  All rights reserved.\n"
141 "\n";
142 
143 /* Components of the first process -- never freed. */
144 struct	session session0;
145 struct	pgrp pgrp0;
146 struct	proc proc0;
147 struct	lwp lwp0;
148 struct	pcred cred0;
149 struct	filedesc0 filedesc0;
150 struct	cwdinfo cwdi0;
151 struct	plimit limit0;
152 struct	pstats pstat0;
153 struct	vmspace vmspace0;
154 struct	sigacts sigacts0;
155 #ifndef curlwp
156 struct	lwp *curlwp = &lwp0;
157 #endif
158 struct	proc *initproc;
159 
160 int	nofile = NOFILE;
161 int	maxuprc = MAXUPRC;
162 int	cmask = CMASK;
163 extern	struct user *proc0paddr;
164 
165 struct	vnode *rootvp, *swapdev_vp;
166 int	boothowto;
167 int	cold = 1;			/* still working on startup */
168 struct	timeval boottime;
169 
170 __volatile int start_init_exec;		/* semaphore for start_init() */
171 
172 static void check_console(struct proc *p);
173 static void start_init(void *);
174 void main(void);
175 
176 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
177 
178 /*
179  * System startup; initialize the world, create process 0, mount root
180  * filesystem, and fork to create init and pagedaemon.  Most of the
181  * hard work is done in the lower-level initialization routines including
182  * startup(), which does memory initialization and autoconfiguration.
183  */
184 void
185 main(void)
186 {
187 	struct lwp *l;
188 	struct proc *p;
189 	struct pdevinit *pdev;
190 	int s, error;
191 	u_int i;
192 	rlim_t lim;
193 	extern struct pdevinit pdevinit[];
194 	extern void schedcpu(void *);
195 #if defined(NFSSERVER) || defined(NFS)
196 	extern void nfs_init(void);
197 #endif
198 #ifdef NVNODE_IMPLICIT
199 	int usevnodes;
200 #endif
201 
202 	/*
203 	 * Initialize the current LWP pointer (curlwp) before
204 	 * any possible traps/probes to simplify trap processing.
205 	 */
206 	simple_lock_init(&proc0.p_raslock);
207 	l = &lwp0;
208 	curlwp = l;
209 	l->l_cpu = curcpu();
210 	l->l_proc = &proc0;
211 	l->l_lid = 1;
212 	/*
213 	 * Attempt to find console and initialize
214 	 * in case of early panic or other messages.
215 	 */
216 	consinit();
217 	printf("%s", copyright);
218 
219 	KERNEL_LOCK_INIT();
220 
221 	uvm_init();
222 
223 	/* Do machine-dependent initialization. */
224 	cpu_startup();
225 
226 	/* Initialize callouts. */
227 	callout_startup();
228 
229 	/*
230 	 * Initialize mbuf's.  Do this now because we might attempt to
231 	 * allocate mbufs or mbuf clusters during autoconfiguration.
232 	 */
233 	mbinit();
234 
235 	/* Initialize kqueues. */
236 	kqueue_init();
237 
238 	/* Initialize sockets. */
239 	soinit();
240 
241 	/*
242 	 * The following things must be done before autoconfiguration.
243 	 */
244 	evcnt_init();		/* initialize event counters */
245 	disk_init();		/* initialize disk list */
246 	tty_init();		/* initialize tty list */
247 #if NRND > 0
248 	rnd_init();		/* initialize RNG */
249 #endif
250 #if NOPENCRYPTO > 0
251 	/* Initialize crypto subsystem before configuring crypto hardware. */
252 	(void)crypto_init();
253 #endif
254 	/* Initialize the sysctl subsystem. */
255 	sysctl_init();
256 
257 	/*
258 	 * Initialize process and pgrp structures.
259 	 */
260 	procinit();
261 
262 #ifdef LKM
263 	/* Initialize the LKM system. */
264 	lkm_init();
265 #endif
266 
267 	/*
268 	 * Create process 0 (the swapper).
269 	 */
270 	p = &proc0;
271 	proc0_insert(p, l, &pgrp0, &session0);
272 
273 	/*
274 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
275 	 * init(8) when they exit.  init(8) can easily wait them out
276 	 * for us.
277 	 */
278 	p->p_flag = P_SYSTEM | P_NOCLDWAIT;
279 	p->p_stat = SACTIVE;
280 	p->p_nice = NZERO;
281 	p->p_emul = &emul_netbsd;
282 #ifdef __HAVE_SYSCALL_INTERN
283 	(*p->p_emul->e_syscall_intern)(p);
284 #endif
285 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
286 
287 	l->l_flag = L_INMEM;
288 	l->l_stat = LSONPROC;
289 	p->p_nrlwps = 1;
290 
291 	callout_init(&l->l_tsleep_ch);
292 
293 	/* Create credentials. */
294 	cred0.p_refcnt = 1;
295 	p->p_cred = &cred0;
296 	p->p_ucred = crget();
297 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
298 
299 	/* Create the file descriptor table. */
300 	finit();
301 	p->p_fd = &filedesc0.fd_fd;
302 	fdinit1(&filedesc0);
303 
304 	/* Create the CWD info. */
305 	p->p_cwdi = &cwdi0;
306 	cwdi0.cwdi_cmask = cmask;
307 	cwdi0.cwdi_refcnt = 1;
308 
309 	/* Create the limits structures. */
310 	p->p_limit = &limit0;
311 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
312 		limit0.pl_rlimit[i].rlim_cur =
313 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
314 
315 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
316 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
317 	    maxfiles < nofile ? maxfiles : nofile;
318 
319 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
320 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
321 	    maxproc < maxuprc ? maxproc : maxuprc;
322 
323 	lim = ptoa(uvmexp.free);
324 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
325 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
326 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
327 	limit0.pl_corename = defcorename;
328 	limit0.p_refcnt = 1;
329 
330 	/*
331 	 * Initialize proc0's vmspace, which uses the kernel pmap.
332 	 * All kernel processes (which never have user space mappings)
333 	 * share proc0's vmspace, and thus, the kernel pmap.
334 	 */
335 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
336 	    trunc_page(VM_MAX_ADDRESS));
337 	p->p_vmspace = &vmspace0;
338 
339 	l->l_addr = proc0paddr;				/* XXX */
340 
341 	p->p_stats = &pstat0;
342 
343 	/*
344 	 * Charge root for one process.
345 	 */
346 	(void)chgproccnt(0, 1);
347 
348 	rqinit();
349 
350 	/* Configure virtual memory system, set vm rlimits. */
351 	uvm_init_limits(p);
352 
353 	/* Initialize the file systems. */
354 #if defined(NFSSERVER) || defined(NFS)
355 	nfs_init();			/* initialize server/shared data */
356 #endif
357 #ifdef NVNODE_IMPLICIT
358 	/*
359 	 * If maximum number of vnodes in namei vnode cache is not explicitly
360 	 * defined in kernel config, adjust the number such as we use roughly
361 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
362 	 */
363 	usevnodes = (ptoa((unsigned)physmem) / 200) / sizeof(struct vnode);
364 	if (usevnodes > desiredvnodes)
365 		desiredvnodes = usevnodes;
366 #endif
367 	vfsinit();
368 
369 	/* Configure the system hardware.  This will enable interrupts. */
370 	configure();
371 
372 	ubc_init();		/* must be after autoconfig */
373 
374 	/* Lock the kernel on behalf of proc0. */
375 	KERNEL_PROC_LOCK(l);
376 
377 #ifdef SYSVSHM
378 	/* Initialize System V style shared memory. */
379 	shminit();
380 #endif
381 
382 #ifdef SYSVSEM
383 	/* Initialize System V style semaphores. */
384 	seminit();
385 #endif
386 
387 #ifdef SYSVMSG
388 	/* Initialize System V style message queues. */
389 	msginit();
390 #endif
391 
392 
393 #ifdef P1003_1B_SEMAPHORE
394 	/* Initialize posix semaphores */
395 	ksem_init();
396 #endif
397 	/* Attach pseudo-devices. */
398 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
399 		(*pdev->pdev_attach)(pdev->pdev_count);
400 
401 	/*
402 	 * Initialize protocols.  Block reception of incoming packets
403 	 * until everything is ready.
404 	 */
405 	s = splnet();
406 	ifinit();
407 	domaininit();
408 	if_attachdomain();
409 	splx(s);
410 
411 #ifdef GPROF
412 	/* Initialize kernel profiling. */
413 	kmstartup();
414 #endif
415 
416 	/* Initialize system accouting. */
417 	acct_init();
418 
419 #ifdef SYSTRACE
420 	systrace_init();
421 #endif
422 	/*
423 	 * Initialize signal-related data structures, and signal state
424 	 * for proc0.
425 	 */
426 	signal_init();
427 	p->p_sigacts = &sigacts0;
428 	siginit(p);
429 
430 	/* Kick off timeout driven events by calling first time. */
431 	schedcpu(NULL);
432 
433 	/*
434 	 * Create process 1 (init(8)).  We do this now, as Unix has
435 	 * historically had init be process 1, and changing this would
436 	 * probably upset a lot of people.
437 	 *
438 	 * Note that process 1 won't immediately exec init(8), but will
439 	 * wait for us to inform it that the root file system has been
440 	 * mounted.
441 	 */
442 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
443 		panic("fork init");
444 
445 	/*
446 	 * Create any kernel threads who's creation was deferred because
447 	 * initproc had not yet been created.
448 	 */
449 	kthread_run_deferred_queue();
450 
451 	/*
452 	 * Now that device driver threads have been created, wait for
453 	 * them to finish any deferred autoconfiguration.  Note we don't
454 	 * need to lock this semaphore, since we haven't booted any
455 	 * secondary processors, yet.
456 	 */
457 	while (config_pending)
458 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
459 
460 	/*
461 	 * Finalize configuration now that all real devices have been
462 	 * found.  This needs to be done before the root device is
463 	 * selected, since finalization may create the root device.
464 	 */
465 	config_finalize();
466 
467 	/*
468 	 * Now that autoconfiguration has completed, we can determine
469 	 * the root and dump devices.
470 	 */
471 	cpu_rootconf();
472 	cpu_dumpconf();
473 
474 	/* Mount the root file system. */
475 	do {
476 		domountroothook();
477 		if ((error = vfs_mountroot())) {
478 			printf("cannot mount root, error = %d\n", error);
479 			boothowto |= RB_ASKNAME;
480 			setroot(root_device,
481 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
482 		}
483 	} while (error != 0);
484 	mountroothook_destroy();
485 
486 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
487 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
488 
489 	/*
490 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
491 	 * reference it.
492 	 */
493 	if (VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode))
494 		panic("cannot find root vnode");
495 	cwdi0.cwdi_cdir = rootvnode;
496 	VREF(cwdi0.cwdi_cdir);
497 	VOP_UNLOCK(rootvnode, 0);
498 	cwdi0.cwdi_rdir = NULL;
499 
500 	/*
501 	 * Now that root is mounted, we can fixup initproc's CWD
502 	 * info.  All other processes are kthreads, which merely
503 	 * share proc0's CWD info.
504 	 */
505 	initproc->p_cwdi->cwdi_cdir = rootvnode;
506 	VREF(initproc->p_cwdi->cwdi_cdir);
507 	initproc->p_cwdi->cwdi_rdir = NULL;
508 
509 	/*
510 	 * Now can look at time, having had a chance to verify the time
511 	 * from the file system.  Reset p->p_rtime as it may have been
512 	 * munched in mi_switch() after the time got set.
513 	 */
514 	proclist_lock_read();
515 	s = splsched();
516 	for (p = LIST_FIRST(&allproc); p != NULL;
517 	     p = LIST_NEXT(p, p_list)) {
518 		p->p_stats->p_start = mono_time = boottime = time;
519 		for (l = LIST_FIRST(&p->p_lwps); l != NULL;
520 		     l = LIST_NEXT(l, l_sibling))
521 			if (l->l_cpu != NULL)
522 				l->l_cpu->ci_schedstate.spc_runtime = time;
523 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
524 	}
525 	splx(s);
526 	proclist_unlock_read();
527 
528 	/* Create the pageout daemon kernel thread. */
529 	uvm_swap_init();
530 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
531 		panic("fork pagedaemon");
532 
533 	/* Create the process reaper kernel thread. */
534 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
535 		panic("fork reaper");
536 
537 	/* Create the filesystem syncer kernel thread. */
538 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
539 		panic("fork syncer");
540 
541 	/* Create the aiodone daemon kernel thread. */
542 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
543 	    "aiodoned"))
544 		panic("fork aiodoned");
545 
546 #if defined(MULTIPROCESSOR)
547 	/* Boot the secondary processors. */
548 	cpu_boot_secondary_processors();
549 #endif
550 
551 	/* Initialize exec structures */
552 	exec_init(1);
553 
554 #ifndef PIPE_SOCKETPAIR
555 	/* Initialize pipe structures */
556 	pipe_init();
557 #endif
558 
559 	/*
560 	 * Okay, now we can let init(8) exec!  It's off to userland!
561 	 */
562 	start_init_exec = 1;
563 	wakeup((void *)&start_init_exec);
564 
565 	/* The scheduler is an infinite loop. */
566 	uvm_scheduler();
567 	/* NOTREACHED */
568 }
569 
570 static void
571 check_console(struct proc *p)
572 {
573 	struct nameidata nd;
574 	int error;
575 
576 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
577 	error = namei(&nd);
578 	if (error == 0)
579 		vrele(nd.ni_vp);
580 	else if (error == ENOENT)
581 		printf("warning: no /dev/console\n");
582 	else
583 		printf("warning: lookup /dev/console: error %d\n", error);
584 }
585 
586 /*
587  * List of paths to try when searching for "init".
588  */
589 static const char *initpaths[] = {
590 	"/sbin/init",
591 	"/sbin/oinit",
592 	"/sbin/init.bak",
593 	NULL,
594 };
595 
596 /*
597  * Start the initial user process; try exec'ing each pathname in "initpaths".
598  * The program is invoked with one argument containing the boot flags.
599  */
600 static void
601 start_init(void *arg)
602 {
603 	struct lwp *l = arg;
604 	struct proc *p = l->l_proc;
605 	vaddr_t addr;
606 	struct sys_execve_args /* {
607 		syscallarg(const char *) path;
608 		syscallarg(char * const *) argp;
609 		syscallarg(char * const *) envp;
610 	} */ args;
611 	int options, i, error;
612 	register_t retval[2];
613 	char flags[4], *flagsp;
614 	const char *path, *slash;
615 	char *ucp, **uap, *arg0, *arg1 = NULL;
616 	char ipath[129];
617 	int ipx, len;
618 
619 	/*
620 	 * Now in process 1.
621 	 */
622 	strncpy(p->p_comm, "init", MAXCOMLEN);
623 
624 	/*
625 	 * Wait for main() to tell us that it's safe to exec.
626 	 */
627 	while (start_init_exec == 0)
628 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
629 
630 	/*
631 	 * This is not the right way to do this.  We really should
632 	 * hand-craft a descriptor onto /dev/console to hand to init,
633 	 * but that's a _lot_ more work, and the benefit from this easy
634 	 * hack makes up for the "good is the enemy of the best" effect.
635 	 */
636 	check_console(p);
637 
638 	/*
639 	 * Need just enough stack to hold the faked-up "execve()" arguments.
640 	 */
641 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
642 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
643                     NULL, UVM_UNKNOWN_OFFSET, 0,
644                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
645 		    UVM_ADV_NORMAL,
646                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
647 		panic("init: couldn't allocate argument space");
648 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
649 
650 	ipx = 0;
651 	while (1) {
652 		if (boothowto & RB_ASKNAME) {
653 			printf("init path");
654 			if (initpaths[ipx])
655 				printf(" (default %s)", initpaths[ipx]);
656 			printf(": ");
657 			len = cngetsn(ipath, sizeof(ipath)-1);
658 			if (len == 0) {
659 				if (initpaths[ipx])
660 					path = initpaths[ipx++];
661 				else
662 					continue;
663 			} else {
664 				ipath[len] = '\0';
665 				path = ipath;
666 			}
667 		} else {
668 			if ((path = initpaths[ipx++]) == NULL)
669 				break;
670 		}
671 
672 		ucp = (char *)USRSTACK;
673 
674 		/*
675 		 * Construct the boot flag argument.
676 		 */
677 		flagsp = flags;
678 		*flagsp++ = '-';
679 		options = 0;
680 
681 		if (boothowto & RB_SINGLE) {
682 			*flagsp++ = 's';
683 			options = 1;
684 		}
685 #ifdef notyet
686 		if (boothowto & RB_FASTBOOT) {
687 			*flagsp++ = 'f';
688 			options = 1;
689 		}
690 #endif
691 
692 		/*
693 		 * Move out the flags (arg 1), if necessary.
694 		 */
695 		if (options != 0) {
696 			*flagsp++ = '\0';
697 			i = flagsp - flags;
698 #ifdef DEBUG
699 			printf("init: copying out flags `%s' %d\n", flags, i);
700 #endif
701 			arg1 = STACK_ALLOC(ucp, i);
702 			ucp = STACK_MAX(arg1, i);
703 			(void)copyout((caddr_t)flags, arg1, i);
704 		}
705 
706 		/*
707 		 * Move out the file name (also arg 0).
708 		 */
709 		i = strlen(path) + 1;
710 #ifdef DEBUG
711 		printf("init: copying out path `%s' %d\n", path, i);
712 #else
713 		if (boothowto & RB_ASKNAME || path != initpaths[0])
714 			printf("init: trying %s\n", path);
715 #endif
716 		arg0 = STACK_ALLOC(ucp, i);
717 		ucp = STACK_MAX(arg0, i);
718 		(void)copyout((caddr_t)path, arg0, i);
719 
720 		/*
721 		 * Move out the arg pointers.
722 		 */
723 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
724 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
725 		SCARG(&args, path) = arg0;
726 		SCARG(&args, argp) = uap;
727 		SCARG(&args, envp) = NULL;
728 		slash = strrchr(path, '/');
729 		if (slash)
730 			(void)suword((caddr_t)uap++,
731 			    (long)arg0 + (slash + 1 - path));
732 		else
733 			(void)suword((caddr_t)uap++, (long)arg0);
734 		if (options != 0)
735 			(void)suword((caddr_t)uap++, (long)arg1);
736 		(void)suword((caddr_t)uap++, 0);	/* terminator */
737 
738 		/*
739 		 * Now try to exec the program.  If can't for any reason
740 		 * other than it doesn't exist, complain.
741 		 */
742 		error = sys_execve(LIST_FIRST(&p->p_lwps), &args, retval);
743 		if (error == 0 || error == EJUSTRETURN) {
744 			KERNEL_PROC_UNLOCK(l);
745 			return;
746 		}
747 		printf("exec %s: error %d\n", path, error);
748 	}
749 	printf("init: not found\n");
750 	panic("no init");
751 }
752