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init_main.c revision 1.251
      1 /*	$NetBSD: init_main.c,v 1.251 2005/08/05 11:03:18 junyoung Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  * (c) UNIX System Laboratories, Inc.
      7  * All or some portions of this file are derived from material licensed
      8  * to the University of California by American Telephone and Telegraph
      9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     10  * the permission of UNIX System Laboratories, Inc.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  *
     36  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
     37  */
     38 
     39 /*
     40  * Copyright (c) 1995 Christopher G. Demetriou.  All rights reserved.
     41  *
     42  * Redistribution and use in source and binary forms, with or without
     43  * modification, are permitted provided that the following conditions
     44  * are met:
     45  * 1. Redistributions of source code must retain the above copyright
     46  *    notice, this list of conditions and the following disclaimer.
     47  * 2. Redistributions in binary form must reproduce the above copyright
     48  *    notice, this list of conditions and the following disclaimer in the
     49  *    documentation and/or other materials provided with the distribution.
     50  * 3. All advertising materials mentioning features or use of this software
     51  *    must display the following acknowledgement:
     52  *	This product includes software developed by the University of
     53  *	California, Berkeley and its contributors.
     54  * 4. Neither the name of the University nor the names of its contributors
     55  *    may be used to endorse or promote products derived from this software
     56  *    without specific prior written permission.
     57  *
     58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     68  * SUCH DAMAGE.
     69  *
     70  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
     71  */
     72 
     73 #include <sys/cdefs.h>
     74 __KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.251 2005/08/05 11:03:18 junyoung Exp $");
     75 
     76 #include "fs_nfs.h"
     77 #include "opt_nfsserver.h"
     78 #include "opt_ipsec.h"
     79 #include "opt_sysv.h"
     80 #include "opt_maxuprc.h"
     81 #include "opt_multiprocessor.h"
     82 #include "opt_pipe.h"
     83 #include "opt_syscall_debug.h"
     84 #include "opt_systrace.h"
     85 #include "opt_posix.h"
     86 #include "opt_kcont.h"
     87 #include "opt_rootfs_magiclinks.h"
     88 #include "opt_verified_exec.h"
     89 
     90 #include "opencrypto.h"
     91 #include "rnd.h"
     92 
     93 #include <sys/param.h>
     94 #include <sys/acct.h>
     95 #include <sys/filedesc.h>
     96 #include <sys/file.h>
     97 #include <sys/errno.h>
     98 #include <sys/callout.h>
     99 #include <sys/kernel.h>
    100 #include <sys/kcont.h>
    101 #include <sys/mount.h>
    102 #include <sys/proc.h>
    103 #include <sys/kthread.h>
    104 #include <sys/resourcevar.h>
    105 #include <sys/signalvar.h>
    106 #include <sys/systm.h>
    107 #include <sys/vnode.h>
    108 #include <sys/tty.h>
    109 #include <sys/conf.h>
    110 #include <sys/disklabel.h>
    111 #include <sys/buf.h>
    112 #include <sys/device.h>
    113 #include <sys/exec.h>
    114 #include <sys/socketvar.h>
    115 #include <sys/protosw.h>
    116 #include <sys/reboot.h>
    117 #include <sys/user.h>
    118 #include <sys/sysctl.h>
    119 #include <sys/event.h>
    120 #include <sys/mbuf.h>
    121 #ifdef FAST_IPSEC
    122 #include <netipsec/ipsec.h>
    123 #endif
    124 #ifdef SYSVSHM
    125 #include <sys/shm.h>
    126 #endif
    127 #ifdef SYSVSEM
    128 #include <sys/sem.h>
    129 #endif
    130 #ifdef SYSVMSG
    131 #include <sys/msg.h>
    132 #endif
    133 #ifdef P1003_1B_SEMAPHORE
    134 #include <sys/ksem.h>
    135 #endif
    136 #ifdef SYSTRACE
    137 #include <sys/systrace.h>
    138 #endif
    139 #include <sys/domain.h>
    140 #include <sys/namei.h>
    141 #if NOPENCRYPTO > 0
    142 #include <opencrypto/cryptodev.h>	/* XXX really the framework */
    143 #endif
    144 #if NRND > 0
    145 #include <sys/rnd.h>
    146 #endif
    147 #ifndef PIPE_SOCKETPAIR
    148 #include <sys/pipe.h>
    149 #endif
    150 #ifdef LKM
    151 #include <sys/lkm.h>
    152 #endif
    153 #ifdef VERIFIED_EXEC
    154 #include <sys/verified_exec.h>
    155 #endif
    156 
    157 #include <sys/syscall.h>
    158 #include <sys/sa.h>
    159 #include <sys/syscallargs.h>
    160 
    161 #include <ufs/ufs/quota.h>
    162 
    163 #include <miscfs/genfs/genfs.h>
    164 #include <miscfs/syncfs/syncfs.h>
    165 
    166 #include <machine/cpu.h>
    167 
    168 #include <uvm/uvm.h>
    169 
    170 #include <dev/cons.h>
    171 
    172 #include <net/if.h>
    173 #include <net/raw_cb.h>
    174 
    175 extern struct proc proc0;
    176 extern struct lwp lwp0;
    177 extern struct cwdinfo cwdi0;
    178 
    179 #ifndef curlwp
    180 struct	lwp *curlwp = &lwp0;
    181 #endif
    182 struct	proc *initproc;
    183 
    184 struct	vnode *rootvp, *swapdev_vp;
    185 int	boothowto;
    186 int	cold = 1;			/* still working on startup */
    187 struct	timeval boottime;
    188 time_t	rootfstime;			/* recorded root fs time, if known */
    189 
    190 __volatile int start_init_exec;		/* semaphore for start_init() */
    191 
    192 static void check_console(struct proc *p);
    193 static void start_init(void *);
    194 void main(void);
    195 
    196 /*
    197  * System startup; initialize the world, create process 0, mount root
    198  * filesystem, and fork to create init and pagedaemon.  Most of the
    199  * hard work is done in the lower-level initialization routines including
    200  * startup(), which does memory initialization and autoconfiguration.
    201  */
    202 void
    203 main(void)
    204 {
    205 	struct lwp *l;
    206 	struct proc *p;
    207 	struct pdevinit *pdev;
    208 	int s, error;
    209 	extern struct pdevinit pdevinit[];
    210 	extern void schedcpu(void *);
    211 #if defined(NFSSERVER) || defined(NFS)
    212 	extern void nfs_init(void);
    213 #endif
    214 #ifdef NVNODE_IMPLICIT
    215 	int usevnodes;
    216 #endif
    217 
    218 	/*
    219 	 * Initialize the current LWP pointer (curlwp) before
    220 	 * any possible traps/probes to simplify trap processing.
    221 	 */
    222 	l = &lwp0;
    223 	curlwp = l;
    224 	l->l_cpu = curcpu();
    225 	l->l_proc = &proc0;
    226 	l->l_lid = 1;
    227 
    228 	/*
    229 	 * Attempt to find console and initialize
    230 	 * in case of early panic or other messages.
    231 	 */
    232 	consinit();
    233 
    234 	KERNEL_LOCK_INIT();
    235 
    236 	uvm_init();
    237 
    238 	/* Do machine-dependent initialization. */
    239 	cpu_startup();
    240 
    241 	/* Initialize callouts. */
    242 	callout_startup();
    243 
    244 	/* Initialize the buffer cache */
    245 	bufinit();
    246 
    247 	/*
    248 	 * Initialize mbuf's.  Do this now because we might attempt to
    249 	 * allocate mbufs or mbuf clusters during autoconfiguration.
    250 	 */
    251 	mbinit();
    252 
    253 	/* Initialize sockets. */
    254 	soinit();
    255 
    256 #ifdef KCONT
    257 	/* Initialize kcont. */
    258         kcont_init();
    259 #endif
    260 
    261 	/*
    262 	 * The following things must be done before autoconfiguration.
    263 	 */
    264 	evcnt_init();		/* initialize event counters */
    265 	tty_init();		/* initialize tty list */
    266 #if NRND > 0
    267 	rnd_init();		/* initialize RNG */
    268 #endif
    269 #if NOPENCRYPTO > 0
    270 	/* Initialize crypto subsystem before configuring crypto hardware. */
    271 	(void)crypto_init();
    272 #endif
    273 	/* Initialize the sysctl subsystem. */
    274 	sysctl_init();
    275 
    276 	/* Initialize process and pgrp structures. */
    277 	procinit();
    278 
    279 #ifdef LKM
    280 	/* Initialize the LKM system. */
    281 	lkm_init();
    282 #endif
    283 
    284 	/* Initialize signal-related data structures. */
    285 	signal_init();
    286 
    287 	/* Create process 0 (the swapper). */
    288 	proc0_init();
    289 
    290 	/*
    291 	 * Charge root for one process.
    292 	 */
    293 	(void)chgproccnt(0, 1);
    294 
    295 	rqinit();
    296 
    297 	/* Initialize the file systems. */
    298 #if defined(NFSSERVER) || defined(NFS)
    299 	nfs_init();			/* initialize server/shared data */
    300 #endif
    301 #ifdef NVNODE_IMPLICIT
    302 	/*
    303 	 * If maximum number of vnodes in namei vnode cache is not explicitly
    304 	 * defined in kernel config, adjust the number such as we use roughly
    305 	 * 1.0% of memory for vnode cache (but not less than NVNODE vnodes).
    306 	 */
    307 	usevnodes = (ptoa((unsigned)physmem) / 100) / sizeof(struct vnode);
    308 	if (usevnodes > desiredvnodes)
    309 		desiredvnodes = usevnodes;
    310 #endif
    311 	vfsinit();
    312 
    313 	/* Configure the system hardware.  This will enable interrupts. */
    314 	configure();
    315 
    316 	ubc_init();		/* must be after autoconfig */
    317 
    318 	/* Lock the kernel on behalf of proc0. */
    319 	KERNEL_PROC_LOCK(l);
    320 
    321 #ifdef SYSVSHM
    322 	/* Initialize System V style shared memory. */
    323 	shminit();
    324 #endif
    325 
    326 #ifdef SYSVSEM
    327 	/* Initialize System V style semaphores. */
    328 	seminit();
    329 #endif
    330 
    331 #ifdef SYSVMSG
    332 	/* Initialize System V style message queues. */
    333 	msginit();
    334 #endif
    335 
    336 #ifdef P1003_1B_SEMAPHORE
    337 	/* Initialize posix semaphores */
    338 	ksem_init();
    339 #endif
    340 
    341 #ifdef VERIFIED_EXEC
    342 	  /*
    343 	   * Initialise the fingerprint operations vectors before
    344 	   * fingerprints can be loaded.
    345 	   */
    346 	veriexec_init_fp_ops();
    347 #endif
    348 
    349 	/* Attach pseudo-devices. */
    350 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
    351 		(*pdev->pdev_attach)(pdev->pdev_count);
    352 
    353 #ifdef	FAST_IPSEC
    354 	/* Attach network crypto subsystem */
    355 	ipsec_attach();
    356 #endif
    357 
    358 	/*
    359 	 * Initialize protocols.  Block reception of incoming packets
    360 	 * until everything is ready.
    361 	 */
    362 	s = splnet();
    363 	ifinit();
    364 	domaininit();
    365 	if_attachdomain();
    366 	splx(s);
    367 
    368 #ifdef GPROF
    369 	/* Initialize kernel profiling. */
    370 	kmstartup();
    371 #endif
    372 
    373 	/* Initialize system accouting. */
    374 	acct_init();
    375 
    376 #ifdef SYSTRACE
    377 	systrace_init();
    378 #endif
    379 
    380 	/* Kick off timeout driven events by calling first time. */
    381 	schedcpu(NULL);
    382 
    383 	/*
    384 	 * Create process 1 (init(8)).  We do this now, as Unix has
    385 	 * historically had init be process 1, and changing this would
    386 	 * probably upset a lot of people.
    387 	 *
    388 	 * Note that process 1 won't immediately exec init(8), but will
    389 	 * wait for us to inform it that the root file system has been
    390 	 * mounted.
    391 	 */
    392 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
    393 		panic("fork init");
    394 
    395 	/*
    396 	 * Create any kernel threads who's creation was deferred because
    397 	 * initproc had not yet been created.
    398 	 */
    399 	kthread_run_deferred_queue();
    400 
    401 	/*
    402 	 * Now that device driver threads have been created, wait for
    403 	 * them to finish any deferred autoconfiguration.  Note we don't
    404 	 * need to lock this semaphore, since we haven't booted any
    405 	 * secondary processors, yet.
    406 	 */
    407 	while (config_pending)
    408 		(void) tsleep(&config_pending, PWAIT, "cfpend", 0);
    409 
    410 	/*
    411 	 * Finalize configuration now that all real devices have been
    412 	 * found.  This needs to be done before the root device is
    413 	 * selected, since finalization may create the root device.
    414 	 */
    415 	config_finalize();
    416 
    417 	/*
    418 	 * Now that autoconfiguration has completed, we can determine
    419 	 * the root and dump devices.
    420 	 */
    421 	cpu_rootconf();
    422 	cpu_dumpconf();
    423 
    424 	/* Mount the root file system. */
    425 	do {
    426 		domountroothook();
    427 		if ((error = vfs_mountroot())) {
    428 			printf("cannot mount root, error = %d\n", error);
    429 			boothowto |= RB_ASKNAME;
    430 			setroot(root_device,
    431 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
    432 		}
    433 	} while (error != 0);
    434 	mountroothook_destroy();
    435 
    436 	/*
    437 	 * Initialise the time-of-day clock, passing the time recorded
    438 	 * in the root filesystem (if any) for use by systems that
    439 	 * don't have a non-volatile time-of-day device.
    440 	 */
    441 	inittodr(rootfstime);
    442 
    443 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
    444 #ifdef ROOTFS_MAGICLINKS
    445 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_MAGICLINKS;
    446 #endif
    447 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
    448 
    449 	/*
    450 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
    451 	 * reference it.
    452 	 */
    453 	error = VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode);
    454 	if (error)
    455 		panic("cannot find root vnode, error=%d", error);
    456 	cwdi0.cwdi_cdir = rootvnode;
    457 	VREF(cwdi0.cwdi_cdir);
    458 	VOP_UNLOCK(rootvnode, 0);
    459 	cwdi0.cwdi_rdir = NULL;
    460 
    461 	/*
    462 	 * Now that root is mounted, we can fixup initproc's CWD
    463 	 * info.  All other processes are kthreads, which merely
    464 	 * share proc0's CWD info.
    465 	 */
    466 	initproc->p_cwdi->cwdi_cdir = rootvnode;
    467 	VREF(initproc->p_cwdi->cwdi_cdir);
    468 	initproc->p_cwdi->cwdi_rdir = NULL;
    469 
    470 	/*
    471 	 * Now can look at time, having had a chance to verify the time
    472 	 * from the file system.  Reset p->p_rtime as it may have been
    473 	 * munched in mi_switch() after the time got set.
    474 	 */
    475 	proclist_lock_read();
    476 	s = splsched();
    477 	LIST_FOREACH(p, &allproc, p_list) {
    478 		KASSERT((p->p_flag & P_MARKER) == 0);
    479 		p->p_stats->p_start = mono_time = boottime = time;
    480 		LIST_FOREACH(l, &p->p_lwps, l_sibling) {
    481 			if (l->l_cpu != NULL)
    482 				l->l_cpu->ci_schedstate.spc_runtime = time;
    483 		}
    484 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
    485 	}
    486 	splx(s);
    487 	proclist_unlock_read();
    488 
    489 	/* Create the pageout daemon kernel thread. */
    490 	uvm_swap_init();
    491 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
    492 		panic("fork pagedaemon");
    493 
    494 	/* Create the filesystem syncer kernel thread. */
    495 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
    496 		panic("fork syncer");
    497 
    498 	/* Create the aiodone daemon kernel thread. */
    499 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
    500 	    "aiodoned"))
    501 		panic("fork aiodoned");
    502 
    503 #if defined(MULTIPROCESSOR)
    504 	/* Boot the secondary processors. */
    505 	cpu_boot_secondary_processors();
    506 #endif
    507 
    508 	/* Initialize exec structures */
    509 	exec_init(1);
    510 
    511 	/*
    512 	 * Okay, now we can let init(8) exec!  It's off to userland!
    513 	 */
    514 	start_init_exec = 1;
    515 	wakeup(&start_init_exec);
    516 
    517 	/* The scheduler is an infinite loop. */
    518 	uvm_scheduler();
    519 	/* NOTREACHED */
    520 }
    521 
    522 void
    523 setrootfstime(time_t t)
    524 {
    525 
    526 	rootfstime = t;
    527 }
    528 
    529 static void
    530 check_console(struct proc *p)
    531 {
    532 	struct nameidata nd;
    533 	int error;
    534 
    535 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", p);
    536 	error = namei(&nd);
    537 	if (error == 0)
    538 		vrele(nd.ni_vp);
    539 	else if (error == ENOENT)
    540 		printf("warning: no /dev/console\n");
    541 	else
    542 		printf("warning: lookup /dev/console: error %d\n", error);
    543 }
    544 
    545 /*
    546  * List of paths to try when searching for "init".
    547  */
    548 static const char *initpaths[] = {
    549 	"/sbin/init",
    550 	"/sbin/oinit",
    551 	"/sbin/init.bak",
    552 	NULL,
    553 };
    554 
    555 /*
    556  * Start the initial user process; try exec'ing each pathname in "initpaths".
    557  * The program is invoked with one argument containing the boot flags.
    558  */
    559 static void
    560 start_init(void *arg)
    561 {
    562 	struct lwp *l = arg;
    563 	struct proc *p = l->l_proc;
    564 	vaddr_t addr;
    565 	struct sys_execve_args /* {
    566 		syscallarg(const char *) path;
    567 		syscallarg(char * const *) argp;
    568 		syscallarg(char * const *) envp;
    569 	} */ args;
    570 	int options, i, error;
    571 	register_t retval[2];
    572 	char flags[4], *flagsp;
    573 	const char *path, *slash;
    574 	char *ucp, **uap, *arg0, *arg1 = NULL;
    575 	char ipath[129];
    576 	int ipx, len;
    577 
    578 	/*
    579 	 * Now in process 1.
    580 	 */
    581 	strncpy(p->p_comm, "init", MAXCOMLEN);
    582 
    583 	/*
    584 	 * Wait for main() to tell us that it's safe to exec.
    585 	 */
    586 	while (start_init_exec == 0)
    587 		(void) tsleep(&start_init_exec, PWAIT, "initexec", 0);
    588 
    589 	/*
    590 	 * This is not the right way to do this.  We really should
    591 	 * hand-craft a descriptor onto /dev/console to hand to init,
    592 	 * but that's a _lot_ more work, and the benefit from this easy
    593 	 * hack makes up for the "good is the enemy of the best" effect.
    594 	 */
    595 	check_console(p);
    596 
    597 	/*
    598 	 * Need just enough stack to hold the faked-up "execve()" arguments.
    599 	 */
    600 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
    601 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
    602                     NULL, UVM_UNKNOWN_OFFSET, 0,
    603                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
    604 		    UVM_ADV_NORMAL,
    605                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
    606 		panic("init: couldn't allocate argument space");
    607 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
    608 
    609 	ipx = 0;
    610 	while (1) {
    611 		if (boothowto & RB_ASKNAME) {
    612 			printf("init path");
    613 			if (initpaths[ipx])
    614 				printf(" (default %s)", initpaths[ipx]);
    615 			printf(": ");
    616 			len = cngetsn(ipath, sizeof(ipath)-1);
    617 			if (len == 0) {
    618 				if (initpaths[ipx])
    619 					path = initpaths[ipx++];
    620 				else
    621 					continue;
    622 			} else {
    623 				ipath[len] = '\0';
    624 				path = ipath;
    625 			}
    626 		} else {
    627 			if ((path = initpaths[ipx++]) == NULL)
    628 				break;
    629 		}
    630 
    631 		ucp = (char *)USRSTACK;
    632 
    633 		/*
    634 		 * Construct the boot flag argument.
    635 		 */
    636 		flagsp = flags;
    637 		*flagsp++ = '-';
    638 		options = 0;
    639 
    640 		if (boothowto & RB_SINGLE) {
    641 			*flagsp++ = 's';
    642 			options = 1;
    643 		}
    644 #ifdef notyet
    645 		if (boothowto & RB_FASTBOOT) {
    646 			*flagsp++ = 'f';
    647 			options = 1;
    648 		}
    649 #endif
    650 
    651 		/*
    652 		 * Move out the flags (arg 1), if necessary.
    653 		 */
    654 		if (options != 0) {
    655 			*flagsp++ = '\0';
    656 			i = flagsp - flags;
    657 #ifdef DEBUG
    658 			printf("init: copying out flags `%s' %d\n", flags, i);
    659 #endif
    660 			arg1 = STACK_ALLOC(ucp, i);
    661 			ucp = STACK_MAX(arg1, i);
    662 			(void)copyout((caddr_t)flags, arg1, i);
    663 		}
    664 
    665 		/*
    666 		 * Move out the file name (also arg 0).
    667 		 */
    668 		i = strlen(path) + 1;
    669 #ifdef DEBUG
    670 		printf("init: copying out path `%s' %d\n", path, i);
    671 #else
    672 		if (boothowto & RB_ASKNAME || path != initpaths[0])
    673 			printf("init: trying %s\n", path);
    674 #endif
    675 		arg0 = STACK_ALLOC(ucp, i);
    676 		ucp = STACK_MAX(arg0, i);
    677 		(void)copyout(path, arg0, i);
    678 
    679 		/*
    680 		 * Move out the arg pointers.
    681 		 */
    682 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
    683 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
    684 		SCARG(&args, path) = arg0;
    685 		SCARG(&args, argp) = uap;
    686 		SCARG(&args, envp) = NULL;
    687 		slash = strrchr(path, '/');
    688 		if (slash)
    689 			(void)suword((caddr_t)uap++,
    690 			    (long)arg0 + (slash + 1 - path));
    691 		else
    692 			(void)suword((caddr_t)uap++, (long)arg0);
    693 		if (options != 0)
    694 			(void)suword((caddr_t)uap++, (long)arg1);
    695 		(void)suword((caddr_t)uap++, 0);	/* terminator */
    696 
    697 		/*
    698 		 * Now try to exec the program.  If can't for any reason
    699 		 * other than it doesn't exist, complain.
    700 		 */
    701 		error = sys_execve(LIST_FIRST(&p->p_lwps), &args, retval);
    702 		if (error == 0 || error == EJUSTRETURN) {
    703 			KERNEL_PROC_UNLOCK(l);
    704 			return;
    705 		}
    706 		printf("exec %s: error %d\n", path, error);
    707 	}
    708 	printf("init: not found\n");
    709 	panic("no init");
    710 }
    711