xref: /netbsd/sys/kern/init_main.c (revision c4a72b64)
1 /*	$NetBSD: init_main.c,v 1.213 2002/12/05 10:30:00 yamt 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 1.213 2002/12/05 10:30:00 yamt 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 
56 #include "rnd.h"
57 
58 #include <sys/param.h>
59 #include <sys/acct.h>
60 #include <sys/filedesc.h>
61 #include <sys/file.h>
62 #include <sys/errno.h>
63 #include <sys/callout.h>
64 #include <sys/kernel.h>
65 #include <sys/mount.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/disk.h>
78 #include <sys/exec.h>
79 #include <sys/socketvar.h>
80 #include <sys/protosw.h>
81 #include <sys/reboot.h>
82 #include <sys/user.h>
83 #include <sys/sysctl.h>
84 #include <sys/event.h>
85 #ifdef SYSVSHM
86 #include <sys/shm.h>
87 #endif
88 #ifdef SYSVSEM
89 #include <sys/sem.h>
90 #endif
91 #ifdef SYSVMSG
92 #include <sys/msg.h>
93 #endif
94 #ifdef SYSTRACE
95 #include <sys/systrace.h>
96 #endif
97 #include <sys/domain.h>
98 #include <sys/mbuf.h>
99 #include <sys/namei.h>
100 #if NRND > 0
101 #include <sys/rnd.h>
102 #endif
103 #ifndef PIPE_SOCKETPAIR
104 #include <sys/pipe.h>
105 #endif
106 #ifdef LKM
107 #include <sys/lkm.h>
108 #endif
109 
110 #include <sys/syscall.h>
111 #include <sys/syscallargs.h>
112 
113 #include <ufs/ufs/quota.h>
114 
115 #include <miscfs/genfs/genfs.h>
116 #include <miscfs/syncfs/syncfs.h>
117 
118 #include <machine/cpu.h>
119 
120 #include <uvm/uvm.h>
121 
122 #include <dev/cons.h>
123 
124 #include <net/if.h>
125 #include <net/raw_cb.h>
126 
127 const char copyright[] =
128 "Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002\n"
129 "    The NetBSD Foundation, Inc.  All rights reserved.\n"
130 "Copyright (c) 1982, 1986, 1989, 1991, 1993\n"
131 "    The Regents of the University of California.  All rights reserved.\n"
132 "\n";
133 
134 /* Components of the first process -- never freed. */
135 struct	session session0;
136 struct	pgrp pgrp0;
137 struct	proc proc0;
138 struct	pcred cred0;
139 struct	filedesc0 filedesc0;
140 struct	cwdinfo cwdi0;
141 struct	plimit limit0;
142 struct	vmspace vmspace0;
143 struct	sigacts sigacts0;
144 #ifndef curproc
145 struct	proc *curproc = &proc0;
146 #endif
147 struct	proc *initproc;
148 
149 int	cmask = CMASK;
150 extern	struct user *proc0paddr;
151 
152 struct	vnode *rootvp, *swapdev_vp;
153 int	boothowto;
154 int	cold = 1;			/* still working on startup */
155 struct	timeval boottime;
156 
157 __volatile int start_init_exec;		/* semaphore for start_init() */
158 
159 static void check_console(struct proc *p);
160 static void start_init(void *);
161 void main(void);
162 
163 extern const struct emul emul_netbsd;	/* defined in kern_exec.c */
164 
165 /*
166  * System startup; initialize the world, create process 0, mount root
167  * filesystem, and fork to create init and pagedaemon.  Most of the
168  * hard work is done in the lower-level initialization routines including
169  * startup(), which does memory initialization and autoconfiguration.
170  */
171 void
172 main(void)
173 {
174 	struct proc *p;
175 	struct pdevinit *pdev;
176 	int s, error;
177 	u_int i;
178 	rlim_t lim;
179 	extern struct pdevinit pdevinit[];
180 	extern void schedcpu(void *);
181 #if defined(NFSSERVER) || defined(NFS)
182 	extern void nfs_init(void);
183 #endif
184 #ifdef NVNODE_IMPLICIT
185 	int usevnodes;
186 #endif
187 
188 	/*
189 	 * Initialize the current process pointer (curproc) before
190 	 * any possible traps/probes to simplify trap processing.
191 	 */
192 	simple_lock_init(&proc0.p_raslock);
193 	p = &proc0;
194 	curproc = p;
195 	p->p_cpu = curcpu();
196 	/*
197 	 * Attempt to find console and initialize
198 	 * in case of early panic or other messages.
199 	 */
200 	consinit();
201 	printf("%s", copyright);
202 
203 	KERNEL_LOCK_INIT();
204 
205 	uvm_init();
206 
207 	/* Do machine-dependent initialization. */
208 	cpu_startup();
209 
210 	/* Initialize callouts. */
211 	callout_startup();
212 
213 	/*
214 	 * Initialize mbuf's.  Do this now because we might attempt to
215 	 * allocate mbufs or mbuf clusters during autoconfiguration.
216 	 */
217 	mbinit();
218 
219 	/* Initialize kqueues. */
220 	kqueue_init();
221 
222 	/* Initialize sockets. */
223 	soinit();
224 
225 	/*
226 	 * The following things must be done before autoconfiguration.
227 	 */
228 	evcnt_init();		/* initialize event counters */
229 	disk_init();		/* initialize disk list */
230 	tty_init();		/* initialize tty list */
231 #if NRND > 0
232 	rnd_init();		/* initialize RNG */
233 #endif
234 
235 	/* Initialize the sysctl subsystem. */
236 	sysctl_init();
237 
238 	/*
239 	 * Initialize process and pgrp structures.
240 	 */
241 	procinit();
242 
243 #ifdef LKM
244 	/* Initialize the LKM system. */
245 	lkm_init();
246 #endif
247 
248 	/*
249 	 * Create process 0 (the swapper).
250 	 */
251 	s = proclist_lock_write();
252 	LIST_INSERT_HEAD(&allproc, p, p_list);
253 	LIST_INSERT_HEAD(PIDHASH(p->p_pid), p, p_hash);
254 	proclist_unlock_write(s);
255 
256 	p->p_pgrp = &pgrp0;
257 	LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
258 	LIST_INIT(&pgrp0.pg_members);
259 	LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
260 
261 	pgrp0.pg_session = &session0;
262 	session0.s_count = 1;
263 	session0.s_sid = p->p_pid;
264 	session0.s_leader = p;
265 
266 	/*
267 	 * Set P_NOCLDWAIT so that kernel threads are reparented to
268 	 * init(8) when they exit.  init(8) can easily wait them out
269 	 * for us.
270 	 */
271 	p->p_flag = P_INMEM | P_SYSTEM | P_NOCLDWAIT;
272 	p->p_stat = SONPROC;
273 	p->p_nice = NZERO;
274 	p->p_emul = &emul_netbsd;
275 #ifdef __HAVE_SYSCALL_INTERN
276 	(*p->p_emul->e_syscall_intern)(p);
277 #endif
278 	strncpy(p->p_comm, "swapper", MAXCOMLEN);
279 
280 	callout_init(&p->p_realit_ch);
281 	callout_init(&p->p_tsleep_ch);
282 
283 	/* Create credentials. */
284 	cred0.p_refcnt = 1;
285 	p->p_cred = &cred0;
286 	p->p_ucred = crget();
287 	p->p_ucred->cr_ngroups = 1;	/* group 0 */
288 
289 	/* Create the file descriptor table. */
290 	finit();
291 	p->p_fd = &filedesc0.fd_fd;
292 	fdinit1(&filedesc0);
293 
294 	/* Create the CWD info. */
295 	p->p_cwdi = &cwdi0;
296 	cwdi0.cwdi_cmask = cmask;
297 	cwdi0.cwdi_refcnt = 1;
298 
299 	/* Create the limits structures. */
300 	p->p_limit = &limit0;
301 	for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
302 		limit0.pl_rlimit[i].rlim_cur =
303 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
304 
305 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
306 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
307 	    maxfiles < NOFILE ? maxfiles : NOFILE;
308 
309 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
310 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
311 	    maxproc < MAXUPRC ? maxproc : MAXUPRC;
312 
313 	lim = ptoa(uvmexp.free);
314 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
315 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
316 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
317 	limit0.pl_corename = defcorename;
318 	limit0.p_refcnt = 1;
319 
320 	/*
321 	 * Initialize proc0's vmspace, which uses the kernel pmap.
322 	 * All kernel processes (which never have user space mappings)
323 	 * share proc0's vmspace, and thus, the kernel pmap.
324 	 */
325 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
326 	    trunc_page(VM_MAX_ADDRESS));
327 	p->p_vmspace = &vmspace0;
328 
329 	p->p_addr = proc0paddr;				/* XXX */
330 
331 	/*
332 	 * We continue to place resource usage info in the
333 	 * user struct so they're pageable.
334 	 */
335 	p->p_stats = &p->p_addr->u_stats;
336 
337 	/*
338 	 * Charge root for one process.
339 	 */
340 	(void)chgproccnt(0, 1);
341 
342 	rqinit();
343 
344 	/* Configure virtual memory system, set vm rlimits. */
345 	uvm_init_limits(p);
346 
347 	/* Initialize the file systems. */
348 #if defined(NFSSERVER) || defined(NFS)
349 	nfs_init();			/* initialize server/shared data */
350 #endif
351 #ifdef NVNODE_IMPLICIT
352 	/*
353 	 * If maximum number of vnodes in namei vnode cache is not explicitly
354 	 * defined in kernel config, adjust the number such as we use roughly
355 	 * 0.5% of memory for vnode cache (but not less than NVNODE vnodes).
356 	 */
357 	usevnodes = (ptoa((unsigned)physmem) / 200) / sizeof(struct vnode);
358 	if (usevnodes > desiredvnodes)
359 		desiredvnodes = usevnodes;
360 #endif
361 	vfsinit();
362 
363 	/* Configure the system hardware.  This will enable interrupts. */
364 	configure();
365 
366 	ubc_init();		/* must be after autoconfig */
367 
368 	/* Lock the kernel on behalf of proc0. */
369 	KERNEL_PROC_LOCK(p);
370 
371 #ifdef SYSVSHM
372 	/* Initialize System V style shared memory. */
373 	shminit();
374 #endif
375 
376 #ifdef SYSVSEM
377 	/* Initialize System V style semaphores. */
378 	seminit();
379 #endif
380 
381 #ifdef SYSVMSG
382 	/* Initialize System V style message queues. */
383 	msginit();
384 #endif
385 
386 	/* Attach pseudo-devices. */
387 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
388 		(*pdev->pdev_attach)(pdev->pdev_count);
389 
390 	/*
391 	 * Initialize protocols.  Block reception of incoming packets
392 	 * until everything is ready.
393 	 */
394 	s = splnet();
395 	ifinit();
396 	domaininit();
397 	if_attachdomain();
398 	splx(s);
399 
400 #ifdef GPROF
401 	/* Initialize kernel profiling. */
402 	kmstartup();
403 #endif
404 
405 	/* Initialize system accouting. */
406 	acct_init();
407 
408 #ifdef SYSTRACE
409 	systrace_init();
410 #endif
411 	/*
412 	 * Initialize signal-related data structures, and signal state
413 	 * for proc0.
414 	 */
415 	signal_init();
416 	p->p_sigacts = &sigacts0;
417 	siginit(p);
418 
419 	/* Kick off timeout driven events by calling first time. */
420 	schedcpu(NULL);
421 
422 	/*
423 	 * Create process 1 (init(8)).  We do this now, as Unix has
424 	 * historically had init be process 1, and changing this would
425 	 * probably upset a lot of people.
426 	 *
427 	 * Note that process 1 won't immediately exec init(8), but will
428 	 * wait for us to inform it that the root file system has been
429 	 * mounted.
430 	 */
431 	if (fork1(p, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
432 		panic("fork init");
433 
434 	/*
435 	 * Create any kernel threads who's creation was deferred because
436 	 * initproc had not yet been created.
437 	 */
438 	kthread_run_deferred_queue();
439 
440 	/*
441 	 * Now that device driver threads have been created, wait for
442 	 * them to finish any deferred autoconfiguration.  Note we don't
443 	 * need to lock this semaphore, since we haven't booted any
444 	 * secondary processors, yet.
445 	 */
446 	while (config_pending)
447 		(void) tsleep((void *)&config_pending, PWAIT, "cfpend", 0);
448 
449 	/*
450 	 * Finalize configuration now that all real devices have been
451 	 * found.  This needs to be done before the root device is
452 	 * selected, since finalization may create the root device.
453 	 */
454 	config_finalize();
455 
456 	/*
457 	 * Now that autoconfiguration has completed, we can determine
458 	 * the root and dump devices.
459 	 */
460 	cpu_rootconf();
461 	cpu_dumpconf();
462 
463 	/* Mount the root file system. */
464 	do {
465 		domountroothook();
466 		if ((error = vfs_mountroot())) {
467 			printf("cannot mount root, error = %d\n", error);
468 			boothowto |= RB_ASKNAME;
469 			setroot(root_device,
470 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
471 		}
472 	} while (error != 0);
473 	mountroothook_destroy();
474 
475 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
476 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
477 
478 	/*
479 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
480 	 * reference it.
481 	 */
482 	if (VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode))
483 		panic("cannot find root vnode");
484 	cwdi0.cwdi_cdir = rootvnode;
485 	VREF(cwdi0.cwdi_cdir);
486 	VOP_UNLOCK(rootvnode, 0);
487 	cwdi0.cwdi_rdir = NULL;
488 
489 	/*
490 	 * Now that root is mounted, we can fixup initproc's CWD
491 	 * info.  All other processes are kthreads, which merely
492 	 * share proc0's CWD info.
493 	 */
494 	initproc->p_cwdi->cwdi_cdir = rootvnode;
495 	VREF(initproc->p_cwdi->cwdi_cdir);
496 	initproc->p_cwdi->cwdi_rdir = NULL;
497 
498 	/*
499 	 * Now can look at time, having had a chance to verify the time
500 	 * from the file system.  Reset p->p_rtime as it may have been
501 	 * munched in mi_switch() after the time got set.
502 	 */
503 	proclist_lock_read();
504 	s = splsched();
505 	for (p = LIST_FIRST(&allproc); p != NULL;
506 	     p = LIST_NEXT(p, p_list)) {
507 		p->p_stats->p_start = mono_time = boottime = time;
508 		if (p->p_cpu != NULL)
509 			p->p_cpu->ci_schedstate.spc_runtime = time;
510 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
511 	}
512 	splx(s);
513 	proclist_unlock_read();
514 
515 	/* Create the pageout daemon kernel thread. */
516 	uvm_swap_init();
517 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
518 		panic("fork pagedaemon");
519 
520 	/* Create the process reaper kernel thread. */
521 	if (kthread_create1(reaper, NULL, NULL, "reaper"))
522 		panic("fork reaper");
523 
524 	/* Create the filesystem syncer kernel thread. */
525 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
526 		panic("fork syncer");
527 
528 	/* Create the aiodone daemon kernel thread. */
529 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
530 	    "aiodoned"))
531 		panic("fork aiodoned");
532 
533 #if defined(MULTIPROCESSOR)
534 	/* Boot the secondary processors. */
535 	cpu_boot_secondary_processors();
536 #endif
537 
538 	/* Initialize exec structures */
539 	exec_init(1);
540 
541 #ifndef PIPE_SOCKETPAIR
542 	/* Initialize pipe structures */
543 	pipe_init();
544 #endif
545 
546 	/*
547 	 * Okay, now we can let init(8) exec!  It's off to userland!
548 	 */
549 	start_init_exec = 1;
550 	wakeup((void *)&start_init_exec);
551 
552 	/* The scheduler is an infinite loop. */
553 	uvm_scheduler();
554 	/* NOTREACHED */
555 }
556 
557 static void
558 check_console(struct proc *p)
559 {
560 	struct nameidata nd;
561 	int error;
562 
563 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
564 	error = namei(&nd);
565 	if (error == 0)
566 		vrele(nd.ni_vp);
567 	else if (error == ENOENT)
568 		printf("warning: no /dev/console\n");
569 	else
570 		printf("warning: lookup /dev/console: error %d\n", error);
571 }
572 
573 /*
574  * List of paths to try when searching for "init".
575  */
576 static const char *initpaths[] = {
577 	"/sbin/init",
578 	"/sbin/oinit",
579 	"/sbin/init.bak",
580 	NULL,
581 };
582 
583 /*
584  * Start the initial user process; try exec'ing each pathname in "initpaths".
585  * The program is invoked with one argument containing the boot flags.
586  */
587 static void
588 start_init(void *arg)
589 {
590 	struct proc *p = arg;
591 	vaddr_t addr;
592 	struct sys_execve_args /* {
593 		syscallarg(const char *) path;
594 		syscallarg(char * const *) argp;
595 		syscallarg(char * const *) envp;
596 	} */ args;
597 	int options, i, error;
598 	register_t retval[2];
599 	char flags[4], *flagsp;
600 	const char *path, *slash;
601 	char *ucp, **uap, *arg0, *arg1 = NULL;
602 	char ipath[129];
603 	int ipx, len;
604 
605 	/*
606 	 * Now in process 1.
607 	 */
608 	strncpy(p->p_comm, "init", MAXCOMLEN);
609 
610 	/*
611 	 * Wait for main() to tell us that it's safe to exec.
612 	 */
613 	while (start_init_exec == 0)
614 		(void) tsleep((void *)&start_init_exec, PWAIT, "initexec", 0);
615 
616 	/*
617 	 * This is not the right way to do this.  We really should
618 	 * hand-craft a descriptor onto /dev/console to hand to init,
619 	 * but that's a _lot_ more work, and the benefit from this easy
620 	 * hack makes up for the "good is the enemy of the best" effect.
621 	 */
622 	check_console(p);
623 
624 	/*
625 	 * Need just enough stack to hold the faked-up "execve()" arguments.
626 	 */
627 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
628 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
629                     NULL, UVM_UNKNOWN_OFFSET, 0,
630                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
631 		    UVM_ADV_NORMAL,
632                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
633 		panic("init: couldn't allocate argument space");
634 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
635 
636 	ipx = 0;
637 	while (1) {
638 		if (boothowto & RB_ASKNAME) {
639 			printf("init path");
640 			if (initpaths[ipx])
641 				printf(" (default %s)", initpaths[ipx]);
642 			printf(": ");
643 			len = cngetsn(ipath, sizeof(ipath)-1);
644 			if (len == 0) {
645 				if (initpaths[ipx])
646 					path = initpaths[ipx++];
647 				else
648 					continue;
649 			} else {
650 				ipath[len] = '\0';
651 				path = ipath;
652 			}
653 		} else {
654 			if ((path = initpaths[ipx++]) == NULL)
655 				break;
656 		}
657 
658 		ucp = (char *)USRSTACK;
659 
660 		/*
661 		 * Construct the boot flag argument.
662 		 */
663 		flagsp = flags;
664 		*flagsp++ = '-';
665 		options = 0;
666 
667 		if (boothowto & RB_SINGLE) {
668 			*flagsp++ = 's';
669 			options = 1;
670 		}
671 #ifdef notyet
672 		if (boothowto & RB_FASTBOOT) {
673 			*flagsp++ = 'f';
674 			options = 1;
675 		}
676 #endif
677 
678 		/*
679 		 * Move out the flags (arg 1), if necessary.
680 		 */
681 		if (options != 0) {
682 			*flagsp++ = '\0';
683 			i = flagsp - flags;
684 #ifdef DEBUG
685 			printf("init: copying out flags `%s' %d\n", flags, i);
686 #endif
687 			arg1 = STACK_ALLOC(ucp, i);
688 			ucp = STACK_MAX(arg1, i);
689 			(void)copyout((caddr_t)flags, arg1, i);
690 		}
691 
692 		/*
693 		 * Move out the file name (also arg 0).
694 		 */
695 		i = strlen(path) + 1;
696 #ifdef DEBUG
697 		printf("init: copying out path `%s' %d\n", path, i);
698 #else
699 		if (boothowto & RB_ASKNAME || path != initpaths[0])
700 			printf("init: trying %s\n", path);
701 #endif
702 		arg0 = STACK_ALLOC(ucp, i);
703 		ucp = STACK_MAX(arg0, i);
704 		(void)copyout((caddr_t)path, arg0, i);
705 
706 		/*
707 		 * Move out the arg pointers.
708 		 */
709 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
710 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
711 		SCARG(&args, path) = arg0;
712 		SCARG(&args, argp) = uap;
713 		SCARG(&args, envp) = NULL;
714 		slash = strrchr(path, '/');
715 		if (slash)
716 			(void)suword((caddr_t)uap++,
717 			    (long)arg0 + (slash + 1 - path));
718 		else
719 			(void)suword((caddr_t)uap++, (long)arg0);
720 		if (options != 0)
721 			(void)suword((caddr_t)uap++, (long)arg1);
722 		(void)suword((caddr_t)uap++, 0);	/* terminator */
723 
724 		/*
725 		 * Now try to exec the program.  If can't for any reason
726 		 * other than it doesn't exist, complain.
727 		 */
728 		error = sys_execve(p, &args, retval);
729 		if (error == 0 || error == EJUSTRETURN) {
730 			KERNEL_PROC_UNLOCK(p);
731 			return;
732 		}
733 		printf("exec %s: error %d\n", path, error);
734 	}
735 	printf("init: not found\n");
736 	panic("no init");
737 }
738