vfs_lookup.c revision 1.41 1 1.41 soren /* $NetBSD: vfs_lookup.c,v 1.41 2002/08/02 04:49:35 soren Exp $ */
2 1.13 cgd
3 1.10 cgd /*
4 1.12 mycroft * Copyright (c) 1982, 1986, 1989, 1993
5 1.12 mycroft * The Regents of the University of California. All rights reserved.
6 1.10 cgd * (c) UNIX System Laboratories, Inc.
7 1.10 cgd * All or some portions of this file are derived from material licensed
8 1.10 cgd * to the University of California by American Telephone and Telegraph
9 1.10 cgd * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 1.10 cgd * the permission of UNIX System Laboratories, Inc.
11 1.10 cgd *
12 1.10 cgd * Redistribution and use in source and binary forms, with or without
13 1.10 cgd * modification, are permitted provided that the following conditions
14 1.10 cgd * are met:
15 1.10 cgd * 1. Redistributions of source code must retain the above copyright
16 1.10 cgd * notice, this list of conditions and the following disclaimer.
17 1.10 cgd * 2. Redistributions in binary form must reproduce the above copyright
18 1.10 cgd * notice, this list of conditions and the following disclaimer in the
19 1.10 cgd * documentation and/or other materials provided with the distribution.
20 1.10 cgd * 3. All advertising materials mentioning features or use of this software
21 1.10 cgd * must display the following acknowledgement:
22 1.10 cgd * This product includes software developed by the University of
23 1.10 cgd * California, Berkeley and its contributors.
24 1.10 cgd * 4. Neither the name of the University nor the names of its contributors
25 1.10 cgd * may be used to endorse or promote products derived from this software
26 1.10 cgd * without specific prior written permission.
27 1.10 cgd *
28 1.10 cgd * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 1.10 cgd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 1.10 cgd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 1.10 cgd * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 1.10 cgd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 1.10 cgd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 1.10 cgd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 1.10 cgd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 1.10 cgd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 1.10 cgd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 1.10 cgd * SUCH DAMAGE.
39 1.10 cgd *
40 1.26 fvdl * @(#)vfs_lookup.c 8.10 (Berkeley) 5/27/95
41 1.10 cgd */
42 1.38 lukem
43 1.38 lukem #include <sys/cdefs.h>
44 1.41 soren __KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.41 2002/08/02 04:49:35 soren Exp $");
45 1.27 thorpej
46 1.27 thorpej #include "opt_ktrace.h"
47 1.10 cgd
48 1.10 cgd #include <sys/param.h>
49 1.15 cgd #include <sys/systm.h>
50 1.10 cgd #include <sys/syslimits.h>
51 1.10 cgd #include <sys/time.h>
52 1.10 cgd #include <sys/namei.h>
53 1.10 cgd #include <sys/vnode.h>
54 1.10 cgd #include <sys/mount.h>
55 1.10 cgd #include <sys/errno.h>
56 1.39 lukem #include <sys/filedesc.h>
57 1.39 lukem #include <sys/hash.h>
58 1.10 cgd #include <sys/malloc.h>
59 1.10 cgd #include <sys/proc.h>
60 1.40 wrstuden #include <sys/syslog.h>
61 1.12 mycroft
62 1.10 cgd #ifdef KTRACE
63 1.10 cgd #include <sys/ktrace.h>
64 1.10 cgd #endif
65 1.16 christos
66 1.35 thorpej struct pool pnbuf_pool; /* pathname buffer pool */
67 1.37 thorpej struct pool_cache pnbuf_cache; /* pathname buffer cache */
68 1.35 thorpej
69 1.10 cgd /*
70 1.10 cgd * Convert a pathname into a pointer to a locked inode.
71 1.10 cgd *
72 1.10 cgd * The FOLLOW flag is set when symbolic links are to be followed
73 1.10 cgd * when they occur at the end of the name translation process.
74 1.10 cgd * Symbolic links are always followed for all other pathname
75 1.10 cgd * components other than the last.
76 1.10 cgd *
77 1.10 cgd * The segflg defines whether the name is to be copied from user
78 1.10 cgd * space or kernel space.
79 1.10 cgd *
80 1.10 cgd * Overall outline of namei:
81 1.10 cgd *
82 1.10 cgd * copy in name
83 1.10 cgd * get starting directory
84 1.10 cgd * while (!done && !error) {
85 1.10 cgd * call lookup to search path.
86 1.10 cgd * if symbolic link, massage name in buffer and continue
87 1.10 cgd * }
88 1.10 cgd */
89 1.12 mycroft int
90 1.12 mycroft namei(ndp)
91 1.33 augustss struct nameidata *ndp;
92 1.10 cgd {
93 1.30 thorpej struct cwdinfo *cwdi; /* pointer to cwd state */
94 1.33 augustss char *cp; /* pointer into pathname argument */
95 1.33 augustss struct vnode *dp; /* the directory we are searching */
96 1.10 cgd struct iovec aiov; /* uio for reading symbolic links */
97 1.10 cgd struct uio auio;
98 1.23 mycroft int error, linklen;
99 1.12 mycroft struct componentname *cnp = &ndp->ni_cnd;
100 1.10 cgd
101 1.12 mycroft #ifdef DIAGNOSTIC
102 1.12 mycroft if (!cnp->cn_cred || !cnp->cn_proc)
103 1.12 mycroft panic ("namei: bad cred/proc");
104 1.12 mycroft if (cnp->cn_nameiop & (~OPMASK))
105 1.12 mycroft panic ("namei: nameiop contaminated with flags");
106 1.12 mycroft if (cnp->cn_flags & OPMASK)
107 1.12 mycroft panic ("namei: flags contaminated with nameiops");
108 1.12 mycroft #endif
109 1.30 thorpej cwdi = cnp->cn_proc->p_cwdi;
110 1.10 cgd
111 1.10 cgd /*
112 1.10 cgd * Get a buffer for the name to be translated, and copy the
113 1.10 cgd * name into the buffer.
114 1.10 cgd */
115 1.12 mycroft if ((cnp->cn_flags & HASBUF) == 0)
116 1.35 thorpej cnp->cn_pnbuf = PNBUF_GET();
117 1.10 cgd if (ndp->ni_segflg == UIO_SYSSPACE)
118 1.12 mycroft error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
119 1.10 cgd MAXPATHLEN, &ndp->ni_pathlen);
120 1.10 cgd else
121 1.12 mycroft error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
122 1.10 cgd MAXPATHLEN, &ndp->ni_pathlen);
123 1.21 kleink
124 1.21 kleink /*
125 1.21 kleink * POSIX.1 requirement: "" is not a valid file name.
126 1.21 kleink */
127 1.21 kleink if (!error && ndp->ni_pathlen == 1)
128 1.21 kleink error = ENOENT;
129 1.21 kleink
130 1.10 cgd if (error) {
131 1.35 thorpej PNBUF_PUT(cnp->cn_pnbuf);
132 1.10 cgd ndp->ni_vp = NULL;
133 1.10 cgd return (error);
134 1.10 cgd }
135 1.10 cgd ndp->ni_loopcnt = 0;
136 1.21 kleink
137 1.10 cgd #ifdef KTRACE
138 1.12 mycroft if (KTRPOINT(cnp->cn_proc, KTR_NAMEI))
139 1.34 sommerfe ktrnamei(cnp->cn_proc, cnp->cn_pnbuf);
140 1.10 cgd #endif
141 1.10 cgd
142 1.10 cgd /*
143 1.10 cgd * Get starting point for the translation.
144 1.10 cgd */
145 1.30 thorpej if ((ndp->ni_rootdir = cwdi->cwdi_rdir) == NULL)
146 1.11 cgd ndp->ni_rootdir = rootvnode;
147 1.23 mycroft /*
148 1.23 mycroft * Check if starting from root directory or current directory.
149 1.23 mycroft */
150 1.23 mycroft if (cnp->cn_pnbuf[0] == '/') {
151 1.23 mycroft dp = ndp->ni_rootdir;
152 1.23 mycroft VREF(dp);
153 1.23 mycroft } else {
154 1.30 thorpej dp = cwdi->cwdi_cdir;
155 1.23 mycroft VREF(dp);
156 1.23 mycroft }
157 1.10 cgd for (;;) {
158 1.12 mycroft cnp->cn_nameptr = cnp->cn_pnbuf;
159 1.10 cgd ndp->ni_startdir = dp;
160 1.16 christos if ((error = lookup(ndp)) != 0) {
161 1.35 thorpej PNBUF_PUT(cnp->cn_pnbuf);
162 1.10 cgd return (error);
163 1.10 cgd }
164 1.10 cgd /*
165 1.10 cgd * Check for symbolic link
166 1.10 cgd */
167 1.12 mycroft if ((cnp->cn_flags & ISSYMLINK) == 0) {
168 1.12 mycroft if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0)
169 1.35 thorpej PNBUF_PUT(cnp->cn_pnbuf);
170 1.10 cgd else
171 1.12 mycroft cnp->cn_flags |= HASBUF;
172 1.10 cgd return (0);
173 1.10 cgd }
174 1.29 wrstuden if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
175 1.26 fvdl VOP_UNLOCK(ndp->ni_dvp, 0);
176 1.10 cgd if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
177 1.10 cgd error = ELOOP;
178 1.10 cgd break;
179 1.10 cgd }
180 1.25 enami if (ndp->ni_vp->v_mount->mnt_flag & MNT_SYMPERM) {
181 1.25 enami error = VOP_ACCESS(ndp->ni_vp, VEXEC, cnp->cn_cred,
182 1.25 enami cnp->cn_proc);
183 1.25 enami if (error != 0)
184 1.25 enami break;
185 1.25 enami }
186 1.10 cgd if (ndp->ni_pathlen > 1)
187 1.35 thorpej cp = PNBUF_GET();
188 1.10 cgd else
189 1.12 mycroft cp = cnp->cn_pnbuf;
190 1.10 cgd aiov.iov_base = cp;
191 1.10 cgd aiov.iov_len = MAXPATHLEN;
192 1.10 cgd auio.uio_iov = &aiov;
193 1.10 cgd auio.uio_iovcnt = 1;
194 1.10 cgd auio.uio_offset = 0;
195 1.10 cgd auio.uio_rw = UIO_READ;
196 1.10 cgd auio.uio_segflg = UIO_SYSSPACE;
197 1.10 cgd auio.uio_procp = (struct proc *)0;
198 1.10 cgd auio.uio_resid = MAXPATHLEN;
199 1.16 christos error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
200 1.16 christos if (error) {
201 1.23 mycroft badlink:
202 1.10 cgd if (ndp->ni_pathlen > 1)
203 1.35 thorpej PNBUF_PUT(cp);
204 1.10 cgd break;
205 1.10 cgd }
206 1.10 cgd linklen = MAXPATHLEN - auio.uio_resid;
207 1.23 mycroft if (linklen == 0) {
208 1.23 mycroft error = ENOENT;
209 1.23 mycroft goto badlink;
210 1.23 mycroft }
211 1.10 cgd if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
212 1.10 cgd error = ENAMETOOLONG;
213 1.23 mycroft goto badlink;
214 1.10 cgd }
215 1.10 cgd if (ndp->ni_pathlen > 1) {
216 1.28 perry memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen);
217 1.35 thorpej PNBUF_PUT(cnp->cn_pnbuf);
218 1.12 mycroft cnp->cn_pnbuf = cp;
219 1.10 cgd } else
220 1.12 mycroft cnp->cn_pnbuf[linklen] = '\0';
221 1.10 cgd ndp->ni_pathlen += linklen;
222 1.10 cgd vput(ndp->ni_vp);
223 1.10 cgd dp = ndp->ni_dvp;
224 1.23 mycroft /*
225 1.23 mycroft * Check if root directory should replace current directory.
226 1.23 mycroft */
227 1.23 mycroft if (cnp->cn_pnbuf[0] == '/') {
228 1.23 mycroft vrele(dp);
229 1.23 mycroft dp = ndp->ni_rootdir;
230 1.23 mycroft VREF(dp);
231 1.23 mycroft }
232 1.10 cgd }
233 1.35 thorpej PNBUF_PUT(cnp->cn_pnbuf);
234 1.10 cgd vrele(ndp->ni_dvp);
235 1.10 cgd vput(ndp->ni_vp);
236 1.10 cgd ndp->ni_vp = NULL;
237 1.10 cgd return (error);
238 1.10 cgd }
239 1.10 cgd
240 1.10 cgd /*
241 1.39 lukem * Determine the namei hash (for cn_hash) for name.
242 1.39 lukem * If *ep != NULL, hash from name to ep-1.
243 1.39 lukem * If *ep == NULL, hash from name until the first NUL or '/', and
244 1.39 lukem * return the location of this termination character in *ep.
245 1.39 lukem *
246 1.39 lukem * This function returns an equivalent hash to the MI hash32_strn().
247 1.39 lukem * The latter isn't used because in the *ep == NULL case, determining
248 1.39 lukem * the length of the string to the first NUL or `/' and then calling
249 1.39 lukem * hash32_strn() involves unnecessary double-handling of the data.
250 1.39 lukem */
251 1.39 lukem uint32_t
252 1.39 lukem namei_hash(const char *name, const char **ep)
253 1.39 lukem {
254 1.39 lukem uint32_t hash;
255 1.39 lukem
256 1.39 lukem hash = HASH32_STR_INIT;
257 1.39 lukem if (*ep != NULL) {
258 1.39 lukem for (; name < *ep; name++)
259 1.39 lukem hash = hash * 33 + *(uint8_t *)name;
260 1.39 lukem } else {
261 1.39 lukem for (; *name != '\0' && *name != '/'; name++)
262 1.39 lukem hash = hash * 33 + *(uint8_t *)name;
263 1.39 lukem *ep = name;
264 1.39 lukem }
265 1.39 lukem return (hash + (hash >> 5));
266 1.39 lukem }
267 1.39 lukem
268 1.39 lukem /*
269 1.10 cgd * Search a pathname.
270 1.10 cgd * This is a very central and rather complicated routine.
271 1.10 cgd *
272 1.10 cgd * The pathname is pointed to by ni_ptr and is of length ni_pathlen.
273 1.10 cgd * The starting directory is taken from ni_startdir. The pathname is
274 1.10 cgd * descended until done, or a symbolic link is encountered. The variable
275 1.10 cgd * ni_more is clear if the path is completed; it is set to one if a
276 1.10 cgd * symbolic link needing interpretation is encountered.
277 1.10 cgd *
278 1.10 cgd * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
279 1.10 cgd * whether the name is to be looked up, created, renamed, or deleted.
280 1.10 cgd * When CREATE, RENAME, or DELETE is specified, information usable in
281 1.10 cgd * creating, renaming, or deleting a directory entry may be calculated.
282 1.10 cgd * If flag has LOCKPARENT or'ed into it, the parent directory is returned
283 1.10 cgd * locked. If flag has WANTPARENT or'ed into it, the parent directory is
284 1.10 cgd * returned unlocked. Otherwise the parent directory is not returned. If
285 1.10 cgd * the target of the pathname exists and LOCKLEAF is or'ed into the flag
286 1.10 cgd * the target is returned locked, otherwise it is returned unlocked.
287 1.10 cgd * When creating or renaming and LOCKPARENT is specified, the target may not
288 1.10 cgd * be ".". When deleting and LOCKPARENT is specified, the target may be ".".
289 1.10 cgd *
290 1.10 cgd * Overall outline of lookup:
291 1.10 cgd *
292 1.10 cgd * dirloop:
293 1.10 cgd * identify next component of name at ndp->ni_ptr
294 1.10 cgd * handle degenerate case where name is null string
295 1.10 cgd * if .. and crossing mount points and on mounted filesys, find parent
296 1.10 cgd * call VOP_LOOKUP routine for next component name
297 1.10 cgd * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
298 1.10 cgd * component vnode returned in ni_vp (if it exists), locked.
299 1.10 cgd * if result vnode is mounted on and crossing mount points,
300 1.10 cgd * find mounted on vnode
301 1.10 cgd * if more components of name, do next level at dirloop
302 1.10 cgd * return the answer in ni_vp, locked if LOCKLEAF set
303 1.10 cgd * if LOCKPARENT set, return locked parent in ni_dvp
304 1.10 cgd * if WANTPARENT set, return unlocked parent in ni_dvp
305 1.10 cgd */
306 1.12 mycroft int
307 1.12 mycroft lookup(ndp)
308 1.33 augustss struct nameidata *ndp;
309 1.10 cgd {
310 1.33 augustss const char *cp; /* pointer into pathname argument */
311 1.33 augustss struct vnode *dp = 0; /* the directory we are searching */
312 1.10 cgd struct vnode *tdp; /* saved dp */
313 1.10 cgd struct mount *mp; /* mount table entry */
314 1.10 cgd int docache; /* == 0 do not cache last component */
315 1.10 cgd int wantparent; /* 1 => wantparent or lockparent flag */
316 1.12 mycroft int rdonly; /* lookup read-only flag bit */
317 1.10 cgd int error = 0;
318 1.23 mycroft int slashes;
319 1.32 wrstuden int dpunlocked = 0; /* dp has already been unlocked */
320 1.12 mycroft struct componentname *cnp = &ndp->ni_cnd;
321 1.10 cgd
322 1.10 cgd /*
323 1.10 cgd * Setup: break out flag bits into variables.
324 1.10 cgd */
325 1.12 mycroft wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
326 1.12 mycroft docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
327 1.12 mycroft if (cnp->cn_nameiop == DELETE ||
328 1.12 mycroft (wantparent && cnp->cn_nameiop != CREATE))
329 1.10 cgd docache = 0;
330 1.12 mycroft rdonly = cnp->cn_flags & RDONLY;
331 1.10 cgd ndp->ni_dvp = NULL;
332 1.12 mycroft cnp->cn_flags &= ~ISSYMLINK;
333 1.10 cgd dp = ndp->ni_startdir;
334 1.10 cgd ndp->ni_startdir = NULLVP;
335 1.26 fvdl vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
336 1.10 cgd
337 1.23 mycroft /*
338 1.23 mycroft * If we have a leading string of slashes, remove them, and just make
339 1.23 mycroft * sure the current node is a directory.
340 1.23 mycroft */
341 1.23 mycroft cp = cnp->cn_nameptr;
342 1.23 mycroft if (*cp == '/') {
343 1.23 mycroft do {
344 1.23 mycroft cp++;
345 1.23 mycroft } while (*cp == '/');
346 1.23 mycroft ndp->ni_pathlen -= cp - cnp->cn_nameptr;
347 1.23 mycroft cnp->cn_nameptr = cp;
348 1.23 mycroft
349 1.23 mycroft if (dp->v_type != VDIR) {
350 1.23 mycroft error = ENOTDIR;
351 1.23 mycroft goto bad;
352 1.23 mycroft }
353 1.23 mycroft
354 1.23 mycroft /*
355 1.23 mycroft * If we've exhausted the path name, then just return the
356 1.23 mycroft * current node. If the caller requested the parent node (i.e.
357 1.23 mycroft * it's a CREATE, DELETE, or RENAME), and we don't have one
358 1.23 mycroft * (because this is the root directory), then we must fail.
359 1.23 mycroft */
360 1.23 mycroft if (cnp->cn_nameptr[0] == '\0') {
361 1.23 mycroft if (ndp->ni_dvp == NULL && wantparent) {
362 1.23 mycroft error = EISDIR;
363 1.23 mycroft goto bad;
364 1.23 mycroft }
365 1.23 mycroft ndp->ni_vp = dp;
366 1.23 mycroft cnp->cn_flags |= ISLASTCN;
367 1.23 mycroft goto terminal;
368 1.23 mycroft }
369 1.23 mycroft }
370 1.23 mycroft
371 1.10 cgd dirloop:
372 1.10 cgd /*
373 1.10 cgd * Search a new directory.
374 1.10 cgd *
375 1.12 mycroft * The cn_hash value is for use by vfs_cache.
376 1.10 cgd * The last component of the filename is left accessible via
377 1.12 mycroft * cnp->cn_nameptr for callers that need the name. Callers needing
378 1.10 cgd * the name set the SAVENAME flag. When done, they assume
379 1.10 cgd * responsibility for freeing the pathname buffer.
380 1.10 cgd */
381 1.12 mycroft cnp->cn_consume = 0;
382 1.39 lukem cp = NULL;
383 1.39 lukem cnp->cn_hash = namei_hash(cnp->cn_nameptr, &cp);
384 1.12 mycroft cnp->cn_namelen = cp - cnp->cn_nameptr;
385 1.12 mycroft if (cnp->cn_namelen > NAME_MAX) {
386 1.10 cgd error = ENAMETOOLONG;
387 1.10 cgd goto bad;
388 1.10 cgd }
389 1.10 cgd #ifdef NAMEI_DIAGNOSTIC
390 1.10 cgd { char c = *cp;
391 1.41 soren *(char *)cp = '\0';
392 1.19 christos printf("{%s}: ", cnp->cn_nameptr);
393 1.41 soren *(char *)cp = c; }
394 1.10 cgd #endif
395 1.12 mycroft ndp->ni_pathlen -= cnp->cn_namelen;
396 1.10 cgd ndp->ni_next = cp;
397 1.23 mycroft /*
398 1.23 mycroft * If this component is followed by a slash, then move the pointer to
399 1.23 mycroft * the next component forward, and remember that this component must be
400 1.23 mycroft * a directory.
401 1.23 mycroft */
402 1.23 mycroft if (*cp == '/') {
403 1.23 mycroft do {
404 1.23 mycroft cp++;
405 1.23 mycroft } while (*cp == '/');
406 1.23 mycroft slashes = cp - ndp->ni_next;
407 1.23 mycroft ndp->ni_pathlen -= slashes;
408 1.23 mycroft ndp->ni_next = cp;
409 1.23 mycroft cnp->cn_flags |= REQUIREDIR;
410 1.23 mycroft } else {
411 1.23 mycroft slashes = 0;
412 1.23 mycroft cnp->cn_flags &= ~REQUIREDIR;
413 1.23 mycroft }
414 1.23 mycroft /*
415 1.23 mycroft * We do special processing on the last component, whether or not it's
416 1.23 mycroft * a directory. Cache all intervening lookups, but not the final one.
417 1.23 mycroft */
418 1.23 mycroft if (*cp == '\0') {
419 1.23 mycroft if (docache)
420 1.23 mycroft cnp->cn_flags |= MAKEENTRY;
421 1.23 mycroft else
422 1.23 mycroft cnp->cn_flags &= ~MAKEENTRY;
423 1.23 mycroft cnp->cn_flags |= ISLASTCN;
424 1.23 mycroft } else {
425 1.23 mycroft cnp->cn_flags |= MAKEENTRY;
426 1.23 mycroft cnp->cn_flags &= ~ISLASTCN;
427 1.23 mycroft }
428 1.12 mycroft if (cnp->cn_namelen == 2 &&
429 1.12 mycroft cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
430 1.12 mycroft cnp->cn_flags |= ISDOTDOT;
431 1.12 mycroft else
432 1.12 mycroft cnp->cn_flags &= ~ISDOTDOT;
433 1.10 cgd
434 1.10 cgd /*
435 1.10 cgd * Handle "..": two special cases.
436 1.10 cgd * 1. If at root directory (e.g. after chroot)
437 1.12 mycroft * or at absolute root directory
438 1.10 cgd * then ignore it so can't get out.
439 1.40 wrstuden * 1a. If we have somehow gotten out of a jail, warn
440 1.40 wrstuden * and also ignore it so we can't get farther out.
441 1.10 cgd * 2. If this vnode is the root of a mounted
442 1.10 cgd * filesystem, then replace it with the
443 1.10 cgd * vnode which was mounted on so we take the
444 1.10 cgd * .. in the other file system.
445 1.10 cgd */
446 1.12 mycroft if (cnp->cn_flags & ISDOTDOT) {
447 1.10 cgd for (;;) {
448 1.12 mycroft if (dp == ndp->ni_rootdir || dp == rootvnode) {
449 1.10 cgd ndp->ni_dvp = dp;
450 1.10 cgd ndp->ni_vp = dp;
451 1.10 cgd VREF(dp);
452 1.10 cgd goto nextname;
453 1.40 wrstuden }
454 1.40 wrstuden if (ndp->ni_rootdir != rootvnode) {
455 1.40 wrstuden int retval;
456 1.40 wrstuden VOP_UNLOCK(dp, 0);
457 1.40 wrstuden retval = vn_isunder(dp, ndp->ni_rootdir,
458 1.40 wrstuden cnp->cn_proc);
459 1.40 wrstuden vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
460 1.40 wrstuden if (!retval) {
461 1.40 wrstuden /* Oops! We got out of jail! */
462 1.40 wrstuden log(LOG_WARNING,
463 1.40 wrstuden "chrooted pid %d uid %d (%s) "
464 1.40 wrstuden "detected outside of its chroot\n",
465 1.40 wrstuden cnp->cn_proc->p_pid,
466 1.40 wrstuden cnp->cn_proc->p_ucred->cr_uid,
467 1.40 wrstuden cnp->cn_proc->p_comm);
468 1.40 wrstuden /* Put us at the jail root. */
469 1.40 wrstuden vput(dp);
470 1.40 wrstuden dp = ndp->ni_rootdir;
471 1.40 wrstuden ndp->ni_dvp = dp;
472 1.40 wrstuden ndp->ni_vp = dp;
473 1.40 wrstuden VREF(dp);
474 1.40 wrstuden VREF(dp);
475 1.40 wrstuden vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
476 1.40 wrstuden goto nextname;
477 1.40 wrstuden }
478 1.10 cgd }
479 1.10 cgd if ((dp->v_flag & VROOT) == 0 ||
480 1.12 mycroft (cnp->cn_flags & NOCROSSMOUNT))
481 1.10 cgd break;
482 1.10 cgd tdp = dp;
483 1.10 cgd dp = dp->v_mount->mnt_vnodecovered;
484 1.10 cgd vput(tdp);
485 1.10 cgd VREF(dp);
486 1.26 fvdl vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
487 1.10 cgd }
488 1.10 cgd }
489 1.10 cgd
490 1.10 cgd /*
491 1.10 cgd * We now have a segment name to search for, and a directory to search.
492 1.10 cgd */
493 1.12 mycroft unionlookup:
494 1.12 mycroft ndp->ni_dvp = dp;
495 1.26 fvdl ndp->ni_vp = NULL;
496 1.31 wrstuden cnp->cn_flags &= ~PDIRUNLOCK;
497 1.16 christos if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) {
498 1.10 cgd #ifdef DIAGNOSTIC
499 1.10 cgd if (ndp->ni_vp != NULL)
500 1.10 cgd panic("leaf should be empty");
501 1.10 cgd #endif
502 1.10 cgd #ifdef NAMEI_DIAGNOSTIC
503 1.19 christos printf("not found\n");
504 1.10 cgd #endif
505 1.12 mycroft if ((error == ENOENT) &&
506 1.10 cgd (dp->v_flag & VROOT) &&
507 1.10 cgd (dp->v_mount->mnt_flag & MNT_UNION)) {
508 1.10 cgd tdp = dp;
509 1.10 cgd dp = dp->v_mount->mnt_vnodecovered;
510 1.31 wrstuden if (cnp->cn_flags & PDIRUNLOCK)
511 1.31 wrstuden vrele(tdp);
512 1.31 wrstuden else
513 1.31 wrstuden vput(tdp);
514 1.10 cgd VREF(dp);
515 1.26 fvdl vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
516 1.12 mycroft goto unionlookup;
517 1.10 cgd }
518 1.12 mycroft
519 1.10 cgd if (error != EJUSTRETURN)
520 1.10 cgd goto bad;
521 1.10 cgd /*
522 1.23 mycroft * If this was not the last component, or there were trailing
523 1.23 mycroft * slashes, then the name must exist.
524 1.23 mycroft */
525 1.23 mycroft if (cnp->cn_flags & REQUIREDIR) {
526 1.23 mycroft error = ENOENT;
527 1.23 mycroft goto bad;
528 1.23 mycroft }
529 1.23 mycroft /*
530 1.10 cgd * If creating and at end of pathname, then can consider
531 1.10 cgd * allowing file to be created.
532 1.10 cgd */
533 1.26 fvdl if (rdonly) {
534 1.10 cgd error = EROFS;
535 1.10 cgd goto bad;
536 1.10 cgd }
537 1.10 cgd /*
538 1.10 cgd * We return with ni_vp NULL to indicate that the entry
539 1.10 cgd * doesn't currently exist, leaving a pointer to the
540 1.10 cgd * (possibly locked) directory inode in ndp->ni_dvp.
541 1.10 cgd */
542 1.12 mycroft if (cnp->cn_flags & SAVESTART) {
543 1.10 cgd ndp->ni_startdir = ndp->ni_dvp;
544 1.10 cgd VREF(ndp->ni_startdir);
545 1.10 cgd }
546 1.10 cgd return (0);
547 1.10 cgd }
548 1.10 cgd #ifdef NAMEI_DIAGNOSTIC
549 1.19 christos printf("found\n");
550 1.10 cgd #endif
551 1.10 cgd
552 1.12 mycroft /*
553 1.23 mycroft * Take into account any additional components consumed by the
554 1.23 mycroft * underlying filesystem. This will include any trailing slashes after
555 1.23 mycroft * the last component consumed.
556 1.12 mycroft */
557 1.12 mycroft if (cnp->cn_consume > 0) {
558 1.23 mycroft ndp->ni_pathlen -= cnp->cn_consume - slashes;
559 1.23 mycroft ndp->ni_next += cnp->cn_consume - slashes;
560 1.12 mycroft cnp->cn_consume = 0;
561 1.23 mycroft if (ndp->ni_next[0] == '\0')
562 1.23 mycroft cnp->cn_flags |= ISLASTCN;
563 1.12 mycroft }
564 1.12 mycroft
565 1.10 cgd dp = ndp->ni_vp;
566 1.10 cgd /*
567 1.10 cgd * Check to see if the vnode has been mounted on;
568 1.10 cgd * if so find the root of the mounted file system.
569 1.10 cgd */
570 1.10 cgd while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
571 1.12 mycroft (cnp->cn_flags & NOCROSSMOUNT) == 0) {
572 1.26 fvdl if (vfs_busy(mp, 0, 0))
573 1.12 mycroft continue;
574 1.32 wrstuden VOP_UNLOCK(dp, 0);
575 1.26 fvdl error = VFS_ROOT(mp, &tdp);
576 1.26 fvdl vfs_unbusy(mp);
577 1.32 wrstuden if (error) {
578 1.32 wrstuden dpunlocked = 1;
579 1.10 cgd goto bad2;
580 1.32 wrstuden }
581 1.32 wrstuden vrele(dp);
582 1.10 cgd ndp->ni_vp = dp = tdp;
583 1.14 mycroft }
584 1.14 mycroft
585 1.14 mycroft /*
586 1.23 mycroft * Check for symbolic link. Back up over any slashes that we skipped,
587 1.23 mycroft * as we will need them again.
588 1.14 mycroft */
589 1.23 mycroft if ((dp->v_type == VLNK) && (cnp->cn_flags & (FOLLOW|REQUIREDIR))) {
590 1.23 mycroft ndp->ni_pathlen += slashes;
591 1.23 mycroft ndp->ni_next -= slashes;
592 1.14 mycroft cnp->cn_flags |= ISSYMLINK;
593 1.14 mycroft return (0);
594 1.10 cgd }
595 1.10 cgd
596 1.23 mycroft /*
597 1.23 mycroft * Check for directory, if the component was followed by a series of
598 1.23 mycroft * slashes.
599 1.23 mycroft */
600 1.23 mycroft if ((dp->v_type != VDIR) && (cnp->cn_flags & REQUIREDIR)) {
601 1.23 mycroft error = ENOTDIR;
602 1.23 mycroft goto bad2;
603 1.23 mycroft }
604 1.23 mycroft
605 1.10 cgd nextname:
606 1.10 cgd /*
607 1.23 mycroft * Not a symbolic link. If this was not the last component, then
608 1.23 mycroft * continue at the next component, else return.
609 1.10 cgd */
610 1.23 mycroft if (!(cnp->cn_flags & ISLASTCN)) {
611 1.12 mycroft cnp->cn_nameptr = ndp->ni_next;
612 1.10 cgd vrele(ndp->ni_dvp);
613 1.10 cgd goto dirloop;
614 1.10 cgd }
615 1.23 mycroft
616 1.23 mycroft terminal:
617 1.10 cgd /*
618 1.26 fvdl * Disallow directory write attempts on read-only file systems.
619 1.10 cgd */
620 1.26 fvdl if (rdonly &&
621 1.26 fvdl (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
622 1.10 cgd /*
623 1.10 cgd * Disallow directory write attempts on read-only
624 1.10 cgd * file systems.
625 1.10 cgd */
626 1.26 fvdl error = EROFS;
627 1.26 fvdl goto bad2;
628 1.10 cgd }
629 1.23 mycroft if (ndp->ni_dvp != NULL) {
630 1.23 mycroft if (cnp->cn_flags & SAVESTART) {
631 1.23 mycroft ndp->ni_startdir = ndp->ni_dvp;
632 1.23 mycroft VREF(ndp->ni_startdir);
633 1.23 mycroft }
634 1.23 mycroft if (!wantparent)
635 1.23 mycroft vrele(ndp->ni_dvp);
636 1.10 cgd }
637 1.12 mycroft if ((cnp->cn_flags & LOCKLEAF) == 0)
638 1.26 fvdl VOP_UNLOCK(dp, 0);
639 1.10 cgd return (0);
640 1.10 cgd
641 1.10 cgd bad2:
642 1.31 wrstuden if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) &&
643 1.31 wrstuden ((cnp->cn_flags & PDIRUNLOCK) == 0))
644 1.26 fvdl VOP_UNLOCK(ndp->ni_dvp, 0);
645 1.10 cgd vrele(ndp->ni_dvp);
646 1.10 cgd bad:
647 1.32 wrstuden if (dpunlocked)
648 1.32 wrstuden vrele(dp);
649 1.32 wrstuden else
650 1.32 wrstuden vput(dp);
651 1.10 cgd ndp->ni_vp = NULL;
652 1.12 mycroft return (error);
653 1.12 mycroft }
654 1.12 mycroft
655 1.12 mycroft /*
656 1.12 mycroft * Reacquire a path name component.
657 1.12 mycroft */
658 1.12 mycroft int
659 1.12 mycroft relookup(dvp, vpp, cnp)
660 1.12 mycroft struct vnode *dvp, **vpp;
661 1.12 mycroft struct componentname *cnp;
662 1.12 mycroft {
663 1.26 fvdl struct vnode *dp = 0; /* the directory we are searching */
664 1.12 mycroft int docache; /* == 0 do not cache last component */
665 1.12 mycroft int wantparent; /* 1 => wantparent or lockparent flag */
666 1.12 mycroft int rdonly; /* lookup read-only flag bit */
667 1.12 mycroft int error = 0;
668 1.12 mycroft #ifdef NAMEI_DIAGNOSTIC
669 1.12 mycroft int newhash; /* DEBUG: check name hash */
670 1.41 soren const char *cp; /* DEBUG: check name ptr/len */
671 1.12 mycroft #endif
672 1.12 mycroft
673 1.12 mycroft /*
674 1.12 mycroft * Setup: break out flag bits into variables.
675 1.12 mycroft */
676 1.12 mycroft wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
677 1.12 mycroft docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
678 1.12 mycroft if (cnp->cn_nameiop == DELETE ||
679 1.12 mycroft (wantparent && cnp->cn_nameiop != CREATE))
680 1.12 mycroft docache = 0;
681 1.12 mycroft rdonly = cnp->cn_flags & RDONLY;
682 1.12 mycroft cnp->cn_flags &= ~ISSYMLINK;
683 1.12 mycroft dp = dvp;
684 1.26 fvdl vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
685 1.12 mycroft
686 1.12 mycroft /* dirloop: */
687 1.12 mycroft /*
688 1.12 mycroft * Search a new directory.
689 1.12 mycroft *
690 1.12 mycroft * The cn_hash value is for use by vfs_cache.
691 1.12 mycroft * The last component of the filename is left accessible via
692 1.12 mycroft * cnp->cn_nameptr for callers that need the name. Callers needing
693 1.12 mycroft * the name set the SAVENAME flag. When done, they assume
694 1.12 mycroft * responsibility for freeing the pathname buffer.
695 1.12 mycroft */
696 1.12 mycroft #ifdef NAMEI_DIAGNOSTIC
697 1.39 lukem cp = NULL;
698 1.39 lukem newhash = namei_hash(cnp->cn_nameptr, &cp);
699 1.12 mycroft if (newhash != cnp->cn_hash)
700 1.12 mycroft panic("relookup: bad hash");
701 1.12 mycroft if (cnp->cn_namelen != cp - cnp->cn_nameptr)
702 1.12 mycroft panic ("relookup: bad len");
703 1.12 mycroft if (*cp != 0)
704 1.12 mycroft panic("relookup: not last component");
705 1.19 christos printf("{%s}: ", cnp->cn_nameptr);
706 1.12 mycroft #endif
707 1.12 mycroft
708 1.12 mycroft /*
709 1.12 mycroft * Check for degenerate name (e.g. / or "")
710 1.12 mycroft * which is a way of talking about a directory,
711 1.12 mycroft * e.g. like "/." or ".".
712 1.12 mycroft */
713 1.23 mycroft if (cnp->cn_nameptr[0] == '\0')
714 1.23 mycroft panic("relookup: null name");
715 1.12 mycroft
716 1.12 mycroft if (cnp->cn_flags & ISDOTDOT)
717 1.12 mycroft panic ("relookup: lookup on dot-dot");
718 1.12 mycroft
719 1.12 mycroft /*
720 1.12 mycroft * We now have a segment name to search for, and a directory to search.
721 1.12 mycroft */
722 1.16 christos if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
723 1.12 mycroft #ifdef DIAGNOSTIC
724 1.12 mycroft if (*vpp != NULL)
725 1.12 mycroft panic("leaf should be empty");
726 1.12 mycroft #endif
727 1.12 mycroft if (error != EJUSTRETURN)
728 1.12 mycroft goto bad;
729 1.12 mycroft /*
730 1.12 mycroft * If creating and at end of pathname, then can consider
731 1.12 mycroft * allowing file to be created.
732 1.12 mycroft */
733 1.26 fvdl if (rdonly) {
734 1.12 mycroft error = EROFS;
735 1.12 mycroft goto bad;
736 1.12 mycroft }
737 1.12 mycroft /* ASSERT(dvp == ndp->ni_startdir) */
738 1.12 mycroft if (cnp->cn_flags & SAVESTART)
739 1.12 mycroft VREF(dvp);
740 1.12 mycroft /*
741 1.12 mycroft * We return with ni_vp NULL to indicate that the entry
742 1.12 mycroft * doesn't currently exist, leaving a pointer to the
743 1.12 mycroft * (possibly locked) directory inode in ndp->ni_dvp.
744 1.12 mycroft */
745 1.12 mycroft return (0);
746 1.12 mycroft }
747 1.12 mycroft dp = *vpp;
748 1.12 mycroft
749 1.12 mycroft #ifdef DIAGNOSTIC
750 1.12 mycroft /*
751 1.12 mycroft * Check for symbolic link
752 1.12 mycroft */
753 1.12 mycroft if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW))
754 1.12 mycroft panic ("relookup: symlink found.\n");
755 1.12 mycroft #endif
756 1.12 mycroft
757 1.12 mycroft /*
758 1.12 mycroft * Check for read-only file systems.
759 1.12 mycroft */
760 1.26 fvdl if (rdonly &&
761 1.26 fvdl (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
762 1.26 fvdl error = EROFS;
763 1.26 fvdl goto bad2;
764 1.12 mycroft }
765 1.12 mycroft /* ASSERT(dvp == ndp->ni_startdir) */
766 1.12 mycroft if (cnp->cn_flags & SAVESTART)
767 1.12 mycroft VREF(dvp);
768 1.12 mycroft if (!wantparent)
769 1.12 mycroft vrele(dvp);
770 1.12 mycroft if ((cnp->cn_flags & LOCKLEAF) == 0)
771 1.26 fvdl VOP_UNLOCK(dp, 0);
772 1.12 mycroft return (0);
773 1.12 mycroft
774 1.12 mycroft bad2:
775 1.12 mycroft if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
776 1.26 fvdl VOP_UNLOCK(dvp, 0);
777 1.12 mycroft vrele(dvp);
778 1.12 mycroft bad:
779 1.12 mycroft vput(dp);
780 1.12 mycroft *vpp = NULL;
781 1.10 cgd return (error);
782 1.10 cgd }
783