xref: /netbsd-src/sys/nfs/nfs_subs.c (revision 4b30c543a0b21e3ba94f2c569e9a82b4fdb2075f)
1 /*
2  * Copyright (c) 1989 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Rick Macklem at The University of Guelph.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. 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  *	from: @(#)nfs_subs.c	7.41 (Berkeley) 5/15/91
37  *	$Id: nfs_subs.c,v 1.8 1993/09/07 15:41:45 ws Exp $
38  */
39 
40 /*
41  * These functions support the macros and help fiddle mbuf chains for
42  * the nfs op functions. They do things like create the rpc header and
43  * copy data between mbuf chains and uio lists.
44  */
45 #include "param.h"
46 #include "proc.h"
47 #include "filedesc.h"
48 #include "systm.h"
49 #include "kernel.h"
50 #include "mount.h"
51 #include "file.h"
52 #include "vnode.h"
53 #include "namei.h"
54 #include "mbuf.h"
55 
56 #include "../ufs/quota.h"
57 #include "../ufs/inode.h"
58 
59 #include "rpcv2.h"
60 #include "nfsv2.h"
61 #include "nfsnode.h"
62 #include "nfs.h"
63 #include "nfsiom.h"
64 #include "xdr_subs.h"
65 #include "nfsm_subs.h"
66 #include "nfscompress.h"
67 
68 #define TRUE	1
69 #define	FALSE	0
70 
71 /*
72  * Data items converted to xdr at startup, since they are constant
73  * This is kinda hokey, but may save a little time doing byte swaps
74  */
75 u_long nfs_procids[NFS_NPROCS];
76 u_long nfs_xdrneg1;
77 u_long rpc_call, rpc_vers, rpc_reply, rpc_msgdenied,
78 	rpc_mismatch, rpc_auth_unix, rpc_msgaccepted;
79 u_long nfs_vers, nfs_prog, nfs_true, nfs_false;
80 /* And other global data */
81 static u_long *rpc_uidp = (u_long *)0;
82 static u_long nfs_xid = 1;
83 static char *rpc_unixauth;
84 extern long hostid;
85 
86 extern struct proc *nfs_iodwant[NFS_MAXASYNCDAEMON];
87 extern struct nfsreq nfsreqh;
88 
89 /* Function ret types */
90 static char *nfs_unixauth();
91 
92 /*
93  * Maximum number of groups passed through to NFS server.
94  * According to RFC1057 it should be 16.
95  * For release 3.X systems, the maximum value is 8.
96  * For some other servers, the maximum value is 10.
97  */
98 int numgrps = 8;
99 
100 /*
101  * Create the header for an rpc request packet
102  * The function nfs_unixauth() creates a unix style authorization string
103  * and returns a ptr to it.
104  * The hsiz is the size of the rest of the nfs request header.
105  * (just used to decide if a cluster is a good idea)
106  * nb: Note that the prog, vers and procid args are already in xdr byte order
107  */
108 struct mbuf *nfsm_reqh(prog, vers, procid, cred, hsiz, bpos, mb, retxid)
109 	u_long prog;
110 	u_long vers;
111 	u_long procid;
112 	struct ucred *cred;
113 	int hsiz;
114 	caddr_t *bpos;
115 	struct mbuf **mb;
116 	u_long *retxid;
117 {
118 	register struct mbuf *mreq, *m;
119 	register u_long *tl;
120 	struct mbuf *m1;
121 	char *ap;
122 	int asiz, siz;
123 	static char authnull[4*NFSX_UNSIGNED];
124 
125 	NFSMGETHDR(mreq);
126 	if (cred != NOCRED) {
127 	    asiz = ((((cred->cr_ngroups - 1) > numgrps) ? numgrps :
128 		      (cred->cr_ngroups - 1)) << 2);
129 #ifdef FILLINHOST
130 	    asiz += nfsm_rndup(hostnamelen)+(9*NFSX_UNSIGNED);
131 #else
132 	    asiz += 9*NFSX_UNSIGNED;
133 #endif
134 	} else
135 	    asiz = 4 * NFSX_UNSIGNED;
136 
137 	/* If we need a lot, alloc a cluster ?? */
138 	if ((asiz+hsiz+RPC_SIZ) > MHLEN)
139 		MCLGET(mreq, M_WAIT);
140 	mreq->m_len = NFSMSIZ(mreq);
141 	siz = mreq->m_len;
142 	m1 = mreq;
143 	/*
144 	 * Alloc enough mbufs
145 	 * We do it now to avoid all sleeps after the call to nfs_unixauth()
146 	 */
147 	while ((asiz+RPC_SIZ) > siz) {
148 		MGET(m, M_WAIT, MT_DATA);
149 		m1->m_next = m;
150 		m->m_len = MLEN;
151 		siz += MLEN;
152 		m1 = m;
153 	}
154 	tl = mtod(mreq, u_long *);
155 	*tl++ = *retxid = txdr_unsigned(++nfs_xid);
156 	*tl++ = rpc_call;
157 	*tl++ = rpc_vers;
158 	*tl++ = prog;
159 	*tl++ = vers;
160 	*tl++ = procid;
161 
162 	/* Now we can call nfs_unixauth() and copy it in */
163 	if (cred != NOCRED)
164 	    ap = nfs_unixauth(cred);
165 	else
166 	    ap = authnull;
167 	m = mreq;
168 	siz = m->m_len-RPC_SIZ;
169 	if (asiz <= siz) {
170 		bcopy(ap, (caddr_t)tl, asiz);
171 		m->m_len = asiz+RPC_SIZ;
172 	} else {
173 		bcopy(ap, (caddr_t)tl, siz);
174 		ap += siz;
175 		asiz -= siz;
176 		while (asiz > 0) {
177 			siz = (asiz > MLEN) ? MLEN : asiz;
178 			m = m->m_next;
179 			bcopy(ap, mtod(m, caddr_t), siz);
180 			m->m_len = siz;
181 			asiz -= siz;
182 			ap += siz;
183 		}
184 	}
185 
186 	/* Finally, return values */
187 	*mb = m;
188 	*bpos = mtod(m, caddr_t)+m->m_len;
189 	return (mreq);
190 }
191 
192 /*
193  * copies mbuf chain to the uio scatter/gather list
194  */
195 nfsm_mbuftouio(mrep, uiop, siz, dpos)
196 	struct mbuf **mrep;
197 	register struct uio *uiop;
198 	int siz;
199 	caddr_t *dpos;
200 {
201 	register char *mbufcp, *uiocp;
202 	register int xfer, left, len;
203 	register struct mbuf *mp;
204 	long uiosiz, rem;
205 	int error = 0;
206 
207 	mp = *mrep;
208 	mbufcp = *dpos;
209 	len = mtod(mp, caddr_t)+mp->m_len-mbufcp;
210 	rem = nfsm_rndup(siz)-siz;
211 	while (siz > 0) {
212 		if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
213 			return (EFBIG);
214 		left = uiop->uio_iov->iov_len;
215 		uiocp = uiop->uio_iov->iov_base;
216 		if (left > siz)
217 			left = siz;
218 		uiosiz = left;
219 		while (left > 0) {
220 			while (len == 0) {
221 				mp = mp->m_next;
222 				if (mp == NULL)
223 					return (EBADRPC);
224 				mbufcp = mtod(mp, caddr_t);
225 				len = mp->m_len;
226 			}
227 			xfer = (left > len) ? len : left;
228 #ifdef notdef
229 			/* Not Yet.. */
230 			if (uiop->uio_iov->iov_op != NULL)
231 				(*(uiop->uio_iov->iov_op))
232 				(mbufcp, uiocp, xfer);
233 			else
234 #endif
235 			if (uiop->uio_segflg == UIO_SYSSPACE)
236 				bcopy(mbufcp, uiocp, xfer);
237 			else
238 				copyout(mbufcp, uiocp, xfer);
239 			left -= xfer;
240 			len -= xfer;
241 			mbufcp += xfer;
242 			uiocp += xfer;
243 			uiop->uio_offset += xfer;
244 			uiop->uio_resid -= xfer;
245 		}
246 		if (uiop->uio_iov->iov_len <= siz) {
247 			uiop->uio_iovcnt--;
248 			uiop->uio_iov++;
249 		} else {
250 			uiop->uio_iov->iov_base += uiosiz;
251 			uiop->uio_iov->iov_len -= uiosiz;
252 		}
253 		siz -= uiosiz;
254 	}
255 	*dpos = mbufcp;
256 	*mrep = mp;
257 	if (rem > 0) {
258 		if (len < rem)
259 			error = nfs_adv(mrep, dpos, rem, len);
260 		else
261 			*dpos += rem;
262 	}
263 	return (error);
264 }
265 
266 /*
267  * copies a uio scatter/gather list to an mbuf chain...
268  */
269 nfsm_uiotombuf(uiop, mq, siz, bpos)
270 	register struct uio *uiop;
271 	struct mbuf **mq;
272 	int siz;
273 	caddr_t *bpos;
274 {
275 	register char *uiocp;
276 	register struct mbuf *mp, *mp2;
277 	register int xfer, left, len;
278 	int uiosiz, clflg, rem;
279 	char *cp;
280 
281 	if (siz > MLEN)		/* or should it >= MCLBYTES ?? */
282 		clflg = 1;
283 	else
284 		clflg = 0;
285 	rem = nfsm_rndup(siz)-siz;
286 	mp2 = *mq;
287 	while (siz > 0) {
288 		if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
289 			return (EINVAL);
290 		left = uiop->uio_iov->iov_len;
291 		uiocp = uiop->uio_iov->iov_base;
292 		if (left > siz)
293 			left = siz;
294 		uiosiz = left;
295 		while (left > 0) {
296 			MGET(mp, M_WAIT, MT_DATA);
297 			if (clflg)
298 				MCLGET(mp, M_WAIT);
299 			mp->m_len = NFSMSIZ(mp);
300 			mp2->m_next = mp;
301 			mp2 = mp;
302 			xfer = (left > mp->m_len) ? mp->m_len : left;
303 #ifdef notdef
304 			/* Not Yet.. */
305 			if (uiop->uio_iov->iov_op != NULL)
306 				(*(uiop->uio_iov->iov_op))
307 				(uiocp, mtod(mp, caddr_t), xfer);
308 			else
309 #endif
310 			if (uiop->uio_segflg == UIO_SYSSPACE)
311 				bcopy(uiocp, mtod(mp, caddr_t), xfer);
312 			else
313 				copyin(uiocp, mtod(mp, caddr_t), xfer);
314 			len = mp->m_len;
315 			mp->m_len = xfer;
316 			left -= xfer;
317 			uiocp += xfer;
318 			uiop->uio_offset += xfer;
319 			uiop->uio_resid -= xfer;
320 		}
321 		if (uiop->uio_iov->iov_len <= siz) {
322 			uiop->uio_iovcnt--;
323 			uiop->uio_iov++;
324 		} else {
325 			uiop->uio_iov->iov_base += uiosiz;
326 			uiop->uio_iov->iov_len -= uiosiz;
327 		}
328 		siz -= uiosiz;
329 	}
330 	if (rem > 0) {
331 		if (rem > (len-mp->m_len)) {
332 			MGET(mp, M_WAIT, MT_DATA);
333 			mp->m_len = 0;
334 			mp2->m_next = mp;
335 		}
336 		cp = mtod(mp, caddr_t)+mp->m_len;
337 		for (left = 0; left < rem; left++)
338 			*cp++ = '\0';
339 		mp->m_len += rem;
340 		*bpos = cp;
341 	} else
342 		*bpos = mtod(mp, caddr_t)+mp->m_len;
343 	*mq = mp;
344 	return (0);
345 }
346 
347 /*
348  * Help break down an mbuf chain by setting the first siz bytes contiguous
349  * pointed to by returned val.
350  * If Updateflg == True we can overwrite the first part of the mbuf data
351  * This is used by the macros nfsm_disect and nfsm_disecton for tough
352  * cases. (The macros use the vars. dpos and dpos2)
353  */
354 nfsm_disct(mdp, dposp, siz, left, updateflg, cp2)
355 	struct mbuf **mdp;
356 	caddr_t *dposp;
357 	int siz;
358 	int left;
359 	int updateflg;
360 	caddr_t *cp2;
361 {
362 	register struct mbuf *mp, *mp2;
363 	register int siz2, xfer;
364 	register caddr_t tl;
365 
366 	mp = *mdp;
367 	while (left == 0) {
368 		*mdp = mp = mp->m_next;
369 		if (mp == NULL)
370 			return (EBADRPC);
371 		left = mp->m_len;
372 		*dposp = mtod(mp, caddr_t);
373 	}
374 	if (left >= siz) {
375 		*cp2 = *dposp;
376 		*dposp += siz;
377 	} else if (mp->m_next == NULL) {
378 		return (EBADRPC);
379 	} else if (siz > MHLEN) {
380 		panic("nfs S too big");
381 	} else {
382 		/* Iff update, you can overwrite, else must alloc new mbuf */
383 		if (updateflg) {
384 			NFSMINOFF(mp);
385 		} else {
386 			MGET(mp2, M_WAIT, MT_DATA);
387 			mp2->m_next = mp->m_next;
388 			mp->m_next = mp2;
389 			mp->m_len -= left;
390 			mp = mp2;
391 		}
392 		*cp2 = tl = mtod(mp, caddr_t);
393 		bcopy(*dposp, tl, left);		/* Copy what was left */
394 		siz2 = siz-left;
395 		tl += left;
396 		mp2 = mp->m_next;
397 		/* Loop around copying up the siz2 bytes */
398 		while (siz2 > 0) {
399 			if (mp2 == NULL)
400 				return (EBADRPC);
401 			xfer = (siz2 > mp2->m_len) ? mp2->m_len : siz2;
402 			if (xfer > 0) {
403 				bcopy(mtod(mp2, caddr_t), tl, xfer);
404 				NFSMADV(mp2, xfer);
405 				mp2->m_len -= xfer;
406 				tl += xfer;
407 				siz2 -= xfer;
408 			}
409 			if (siz2 > 0)
410 				mp2 = mp2->m_next;
411 		}
412 		mp->m_len = siz;
413 		*mdp = mp2;
414 		*dposp = mtod(mp2, caddr_t);
415 	}
416 	return (0);
417 }
418 
419 /*
420  * Advance the position in the mbuf chain.
421  */
422 nfs_adv(mdp, dposp, offs, left)
423 	struct mbuf **mdp;
424 	caddr_t *dposp;
425 	int offs;
426 	int left;
427 {
428 	register struct mbuf *m;
429 	register int s;
430 
431 	m = *mdp;
432 	s = left;
433 	while (s < offs) {
434 		offs -= s;
435 		m = m->m_next;
436 		if (m == NULL)
437 			return (EBADRPC);
438 		s = m->m_len;
439 	}
440 	*mdp = m;
441 	*dposp = mtod(m, caddr_t)+offs;
442 	return (0);
443 }
444 
445 /*
446  * Copy a string into mbufs for the hard cases...
447  */
448 nfsm_strtmbuf(mb, bpos, cp, siz)
449 	struct mbuf **mb;
450 	char **bpos;
451 	char *cp;
452 	long siz;
453 {
454 	register struct mbuf *m1, *m2;
455 	long left, xfer, len, tlen;
456 	u_long *tl;
457 	int putsize;
458 
459 	putsize = 1;
460 	m2 = *mb;
461 	left = NFSMSIZ(m2)-m2->m_len;
462 	if (left > 0) {
463 		tl = ((u_long *)(*bpos));
464 		*tl++ = txdr_unsigned(siz);
465 		putsize = 0;
466 		left -= NFSX_UNSIGNED;
467 		m2->m_len += NFSX_UNSIGNED;
468 		if (left > 0) {
469 			bcopy(cp, (caddr_t) tl, left);
470 			siz -= left;
471 			cp += left;
472 			m2->m_len += left;
473 			left = 0;
474 		}
475 	}
476 	/* Loop arround adding mbufs */
477 	while (siz > 0) {
478 		MGET(m1, M_WAIT, MT_DATA);
479 		if (siz > MLEN)
480 			MCLGET(m1, M_WAIT);
481 		m1->m_len = NFSMSIZ(m1);
482 		m2->m_next = m1;
483 		m2 = m1;
484 		tl = mtod(m1, u_long *);
485 		tlen = 0;
486 		if (putsize) {
487 			*tl++ = txdr_unsigned(siz);
488 			m1->m_len -= NFSX_UNSIGNED;
489 			tlen = NFSX_UNSIGNED;
490 			putsize = 0;
491 		}
492 		if (siz < m1->m_len) {
493 			len = nfsm_rndup(siz);
494 			xfer = siz;
495 			if (xfer < len)
496 				*(tl+(xfer>>2)) = 0;
497 		} else {
498 			xfer = len = m1->m_len;
499 		}
500 		bcopy(cp, (caddr_t) tl, xfer);
501 		m1->m_len = len+tlen;
502 		siz -= xfer;
503 		cp += xfer;
504 	}
505 	*mb = m1;
506 	*bpos = mtod(m1, caddr_t)+m1->m_len;
507 	return (0);
508 }
509 
510 /*
511  * Called once to initialize data structures...
512  */
513 nfs_init()
514 {
515 	register int i;
516 
517 	rpc_vers = txdr_unsigned(RPC_VER2);
518 	rpc_call = txdr_unsigned(RPC_CALL);
519 	rpc_reply = txdr_unsigned(RPC_REPLY);
520 	rpc_msgdenied = txdr_unsigned(RPC_MSGDENIED);
521 	rpc_msgaccepted = txdr_unsigned(RPC_MSGACCEPTED);
522 	rpc_mismatch = txdr_unsigned(RPC_MISMATCH);
523 	rpc_auth_unix = txdr_unsigned(RPCAUTH_UNIX);
524 	nfs_vers = txdr_unsigned(NFS_VER2);
525 	nfs_prog = txdr_unsigned(NFS_PROG);
526 	nfs_true = txdr_unsigned(TRUE);
527 	nfs_false = txdr_unsigned(FALSE);
528 	/* Loop thru nfs procids */
529 	for (i = 0; i < NFS_NPROCS; i++)
530 		nfs_procids[i] = txdr_unsigned(i);
531 	/* Ensure async daemons disabled */
532 	nfs_xdrneg1 = txdr_unsigned(-1);
533 #ifdef NFSCLIENT
534 	for (i = 0; i < NFS_MAXASYNCDAEMON; i++)
535 		nfs_iodwant[i] = (struct proc *)0;
536 	nfs_nhinit();			/* Init the nfsnode table */
537 #endif /* NFSCLIENT */
538 #ifdef NFSSERVER
539 	nfsrv_initcache();		/* Init the server request cache */
540 #endif /*NFSSERVER */
541 	/*
542 	 * Initialize reply list and start timer
543 	 */
544 	nfsreqh.r_prev = nfsreqh.r_next = &nfsreqh;
545 	nfs_timer();
546 }
547 
548 /*
549  * Fill in the rest of the rpc_unixauth and return it
550  */
551 static char *nfs_unixauth(cr)
552 	register struct ucred *cr;
553 {
554 	register u_long *tl;
555 	register int i;
556 	int ngr;
557 
558 	/* Maybe someday there should be a cache of AUTH_SHORT's */
559 	if ((tl = rpc_uidp) == NULL) {
560 #ifdef FILLINHOST
561 		i = nfsm_rndup(hostnamelen)+(25*NFSX_UNSIGNED);
562 #else
563 		i = 25*NFSX_UNSIGNED;
564 #endif
565 		MALLOC(tl, u_long *, i, M_TEMP, M_WAITOK);
566 		bzero((caddr_t)tl, i);
567 		rpc_unixauth = (caddr_t)tl;
568 		*tl++ = txdr_unsigned(RPCAUTH_UNIX);
569 		tl++;	/* Fill in size later */
570 		*tl++ = hostid;
571 #ifdef FILLINHOST
572 		*tl++ = txdr_unsigned(hostnamelen);
573 		i = nfsm_rndup(hostnamelen);
574 		bcopy(hostname, (caddr_t)tl, hostnamelen);
575 		tl += (i>>2);
576 #else
577 		*tl++ = 0;
578 #endif
579 		rpc_uidp = tl;
580 	}
581 	*tl++ = txdr_unsigned(cr->cr_uid);
582 	*tl++ = txdr_unsigned(cr->cr_groups[0]);
583 	ngr = ((cr->cr_ngroups - 1) > numgrps) ? numgrps : (cr->cr_ngroups - 1);
584 	*tl++ = txdr_unsigned(ngr);
585 	for (i = 1; i <= ngr; i++)
586 		*tl++ = txdr_unsigned(cr->cr_groups[i]);
587 	/* And add the AUTH_NULL */
588 	*tl++ = 0;
589 	*tl = 0;
590 	i = (((caddr_t)tl)-rpc_unixauth)-12;
591 	tl = (u_long *)(rpc_unixauth+4);
592 	*tl = txdr_unsigned(i);
593 	return (rpc_unixauth);
594 }
595 
596 /*
597  * Set up nameidata for a namei() call and do it
598  */
599 nfs_namei(ndp, fhp, len, mdp, dposp, p)
600 	register struct nameidata *ndp;
601 	fhandle_t *fhp;
602 	int len;
603 	struct mbuf **mdp;
604 	caddr_t *dposp;
605 	struct proc *p;
606 {
607 	register int i, rem;
608 	register struct mbuf *md;
609 	register char *fromcp, *tocp;
610 	struct vnode *dp;
611 	int flag;
612 	int error;
613 
614 	flag = ndp->ni_nameiop & OPMASK;
615 	MALLOC(ndp->ni_pnbuf, char *, len + 1, M_NAMEI, M_WAITOK);
616 	/*
617 	 * Copy the name from the mbuf list to ndp->ni_pnbuf
618 	 * and set the various ndp fields appropriately.
619 	 */
620 	fromcp = *dposp;
621 	tocp = ndp->ni_pnbuf;
622 	md = *mdp;
623 	rem = mtod(md, caddr_t) + md->m_len - fromcp;
624 	for (i = 0; i < len; i++) {
625 		while (rem == 0) {
626 			md = md->m_next;
627 			if (md == NULL) {
628 				error = EBADRPC;
629 				goto out;
630 			}
631 			fromcp = mtod(md, caddr_t);
632 			rem = md->m_len;
633 		}
634 		if (*fromcp == '\0' || *fromcp == '/') {
635 			error = EINVAL;
636 			goto out;
637 		}
638 		if (*fromcp & 0200)
639 			if ((*fromcp&0377) == ('/'|0200) || flag != DELETE) {
640 				error = EINVAL;
641 				goto out;
642 			}
643 		*tocp++ = *fromcp++;
644 		rem--;
645 	}
646 	*tocp = '\0';
647 	*mdp = md;
648 	*dposp = fromcp;
649 	len = nfsm_rndup(len)-len;
650 	if (len > 0) {
651 		if (rem >= len)
652 			*dposp += len;
653 		else if (error = nfs_adv(mdp, dposp, len, rem))
654 			goto out;
655 	}
656 	ndp->ni_pathlen = tocp - ndp->ni_pnbuf;
657 	ndp->ni_ptr = ndp->ni_pnbuf;
658 	/*
659 	 * Extract and set starting directory.
660 	 */
661 	if (error = nfsrv_fhtovp(fhp, FALSE, &dp, ndp->ni_cred))
662 		goto out;
663 	if (dp->v_type != VDIR) {
664 		vrele(dp);
665 		error = ENOTDIR;
666 		goto out;
667 	}
668 	ndp->ni_startdir = dp;
669 	ndp->ni_nameiop |= (NOCROSSMOUNT | REMOTE);
670 	/*
671 	 * And call lookup() to do the real work
672 	 */
673 	if (error = lookup(ndp, p))
674 		goto out;
675 	/*
676 	 * Check for encountering a symbolic link
677 	 */
678 	if (ndp->ni_more) {
679 		if ((ndp->ni_nameiop & LOCKPARENT) && ndp->ni_pathlen == 1)
680 			vput(ndp->ni_dvp);
681 		else
682 			vrele(ndp->ni_dvp);
683 		vput(ndp->ni_vp);
684 		ndp->ni_vp = NULL;
685 		error = EINVAL;
686 		goto out;
687 	}
688 	/*
689 	 * Check for saved name request
690 	 */
691 	if (ndp->ni_nameiop & (SAVENAME | SAVESTART)) {
692 		ndp->ni_nameiop |= HASBUF;
693 		return (0);
694 	}
695 out:
696 	FREE(ndp->ni_pnbuf, M_NAMEI);
697 	return (error);
698 }
699 
700 /*
701  * A fiddled version of m_adj() that ensures null fill to a long
702  * boundary and only trims off the back end
703  */
704 nfsm_adj(mp, len, nul)
705 	struct mbuf *mp;
706 	register int len;
707 	int nul;
708 {
709 	register struct mbuf *m;
710 	register int count, i;
711 	register char *cp;
712 
713 	/*
714 	 * Trim from tail.  Scan the mbuf chain,
715 	 * calculating its length and finding the last mbuf.
716 	 * If the adjustment only affects this mbuf, then just
717 	 * adjust and return.  Otherwise, rescan and truncate
718 	 * after the remaining size.
719 	 */
720 	count = 0;
721 	m = mp;
722 	for (;;) {
723 		count += m->m_len;
724 		if (m->m_next == (struct mbuf *)0)
725 			break;
726 		m = m->m_next;
727 	}
728 	if (m->m_len > len) {
729 		m->m_len -= len;
730 		if (nul > 0) {
731 			cp = mtod(m, caddr_t)+m->m_len-nul;
732 			for (i = 0; i < nul; i++)
733 				*cp++ = '\0';
734 		}
735 		return;
736 	}
737 	count -= len;
738 	if (count < 0)
739 		count = 0;
740 	/*
741 	 * Correct length for chain is "count".
742 	 * Find the mbuf with last data, adjust its length,
743 	 * and toss data from remaining mbufs on chain.
744 	 */
745 	for (m = mp; m; m = m->m_next) {
746 		if (m->m_len >= count) {
747 			m->m_len = count;
748 			if (nul > 0) {
749 				cp = mtod(m, caddr_t)+m->m_len-nul;
750 				for (i = 0; i < nul; i++)
751 					*cp++ = '\0';
752 			}
753 			break;
754 		}
755 		count -= m->m_len;
756 	}
757 	while (m = m->m_next)
758 		m->m_len = 0;
759 }
760 
761 /*
762  * nfsrv_fhtovp() - convert a fh to a vnode ptr (optionally locked)
763  * 	- look up fsid in mount list (if not found ret error)
764  *	- check that it is exported
765  *	- get vp by calling VFS_FHTOVP() macro
766  *	- if not lockflag unlock it with VOP_UNLOCK()
767  *	- if cred->cr_uid == 0 set it to m_exroot
768  */
769 nfsrv_fhtovp(fhp, lockflag, vpp, cred)
770 	fhandle_t *fhp;
771 	int lockflag;
772 	struct vnode **vpp;
773 	struct ucred *cred;
774 {
775 	register struct mount *mp;
776 
777 	if ((mp = getvfs(&fhp->fh_fsid)) == NULL)
778 		return (ESTALE);
779 	if ((mp->mnt_flag & MNT_EXPORTED) == 0)
780 		return (EACCES);
781 	if (VFS_FHTOVP(mp, &fhp->fh_fid, vpp))
782 		return (ESTALE);
783 	if (cred->cr_uid == 0)
784 		cred->cr_uid = mp->mnt_exroot;
785 	if (!lockflag)
786 		VOP_UNLOCK(*vpp);
787 	return (0);
788 }
789 
790 /*
791  * These two functions implement nfs rpc compression.
792  * The algorithm is a trivial run length encoding of '\0' bytes. The high
793  * order nibble of hex "e" is or'd with the number of zeroes - 2 in four
794  * bits. (2 - 17 zeros) Any data byte with a high order nibble of hex "e"
795  * is byte stuffed.
796  * The compressed data is padded with 0x0 bytes to an even multiple of
797  * 4 bytes in length to avoid any weird long pointer alignments.
798  * If compression/uncompression is unsuccessful, the original mbuf list
799  * is returned.
800  * The first four bytes (the XID) are left uncompressed and the fifth
801  * byte is set to 0x1 for request and 0x2 for reply.
802  * An uncompressed RPC will always have the fifth byte == 0x0.
803  */
804 struct mbuf *
805 nfs_compress(m0)
806 	struct mbuf *m0;
807 {
808 	register u_char ch, nextch;
809 	register int i, rlelast;
810 	register u_char *ip, *op;
811 	register int ileft, oleft, noteof;
812 	register struct mbuf *m, *om;
813 	struct mbuf **mp, *retm;
814 	int olen, clget;
815 
816 	i = rlelast = 0;
817 	noteof = 1;
818 	m = m0;
819 	if (m->m_len < 12)
820 		return (m0);
821 	if (m->m_pkthdr.len >= MINCLSIZE)
822 		clget = 1;
823 	else
824 		clget = 0;
825 	ileft = m->m_len - 9;
826 	ip = mtod(m, u_char *);
827 	MGETHDR(om, M_WAIT, MT_DATA);
828 	if (clget)
829 		MCLGET(om, M_WAIT);
830 	retm = om;
831 	mp = &om->m_next;
832 	olen = om->m_len = 5;
833 	oleft = M_TRAILINGSPACE(om);
834 	op = mtod(om, u_char *);
835 	*((u_long *)op) = *((u_long *)ip);
836 	ip += 7;
837 	op += 4;
838 	*op++ = *ip++ + 1;
839 	nextch = *ip++;
840 	while (noteof) {
841 		ch = nextch;
842 		if (ileft == 0) {
843 			do {
844 				m = m->m_next;
845 			} while (m && m->m_len == 0);
846 			if (m) {
847 				ileft = m->m_len;
848 				ip = mtod(m, u_char *);
849 			} else {
850 				noteof = 0;
851 				nextch = 0x1;
852 				goto doit;
853 			}
854 		}
855 		nextch = *ip++;
856 		ileft--;
857 doit:
858 		if (ch == '\0') {
859 			if (++i == NFSC_MAX || nextch != '\0') {
860 				if (i < 2) {
861 					nfscput('\0');
862 				} else {
863 					if (rlelast == i) {
864 						nfscput('\0');
865 						i--;
866 					}
867 					if (NFSCRLE(i) == (nextch & 0xff)) {
868 						i--;
869 						if (i < 2) {
870 							nfscput('\0');
871 						} else {
872 							nfscput(NFSCRLE(i));
873 						}
874 						nfscput('\0');
875 						rlelast = 0;
876 					} else {
877 						nfscput(NFSCRLE(i));
878 						rlelast = i;
879 					}
880 				}
881 				i = 0;
882 			}
883 		} else {
884 			if ((ch & NFSCRL) == NFSCRL) {
885 				nfscput(ch);
886 			}
887 			nfscput(ch);
888 			i = rlelast = 0;
889 		}
890 	}
891 	if (olen < m0->m_pkthdr.len) {
892 		m_freem(m0);
893 		if (i = (olen & 0x3)) {
894 			i = 4 - i;
895 			while (i-- > 0) {
896 				nfscput('\0');
897 			}
898 		}
899 		retm->m_pkthdr.len = olen;
900 		retm->m_pkthdr.rcvif = (struct ifnet *)0;
901 		return (retm);
902 	} else {
903 		m_freem(retm);
904 		return (m0);
905 	}
906 }
907 
908 struct mbuf *
909 nfs_uncompress(m0)
910 	struct mbuf *m0;
911 {
912 	register u_char cp, nextcp, *ip, *op;
913 	register struct mbuf *m, *om;
914 	struct mbuf *retm, **mp;
915 	int i, j, noteof, clget, ileft, oleft, olen;
916 
917 	m = m0;
918 	i = 0;
919 	while (m && i < MINCLSIZE) {
920 		i += m->m_len;
921 		m = m->m_next;
922 	}
923 	if (i < 6)
924 		return (m0);
925 	if (i >= MINCLSIZE)
926 		clget = 1;
927 	else
928 		clget = 0;
929 	m = m0;
930 	MGET(om, M_WAIT, MT_DATA);
931 	if (clget)
932 		MCLGET(om, M_WAIT);
933 	olen = om->m_len = 8;
934 	oleft = M_TRAILINGSPACE(om);
935 	op = mtod(om, u_char *);
936 	retm = om;
937 	mp = &om->m_next;
938 	if (m->m_len >= 6) {
939 		ileft = m->m_len - 6;
940 		ip = mtod(m, u_char *);
941 		*((u_long *)op) = *((u_long *)ip);
942 		bzero(op + 4, 3);
943 		ip += 4;
944 		op += 7;
945 		if (*ip == '\0') {
946 			m_freem(om);
947 			return (m0);
948 		}
949 		*op++ = *ip++ - 1;
950 		cp = *ip++;
951 	} else {
952 		ileft = m->m_len;
953 		ip = mtod(m, u_char *);
954 		nfscget(*op++);
955 		nfscget(*op++);
956 		nfscget(*op++);
957 		nfscget(*op++);
958 		bzero(op, 3);
959 		op += 3;
960 		nfscget(*op);
961 		if (*op == '\0') {
962 			m_freem(om);
963 			return (m0);
964 		}
965 		(*op)--;
966 		op++;
967 		nfscget(cp);
968 	}
969 	noteof = 1;
970 	while (noteof) {
971 		if ((cp & NFSCRL) == NFSCRL) {
972 			nfscget(nextcp);
973 			if (cp == nextcp) {
974 				nfscput(cp);
975 				goto readit;
976 			} else {
977 				i = (cp & 0xf) + 2;
978 				for (j = 0; j < i; j++) {
979 					nfscput('\0');
980 				}
981 				cp = nextcp;
982 			}
983 		} else {
984 			nfscput(cp);
985 readit:
986 			nfscget(cp);
987 		}
988 	}
989 	m_freem(m0);
990 	if (i = (olen & 0x3))
991 		om->m_len -= i;
992 	return (retm);
993 }
994