Rename printf -> kprintf in sys/ and add some defines where necessary
[dragonfly.git] / sys / kern / vfs_nlookup.c
CommitLineData
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1/*
2 * Copyright (c) 2004 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
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
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
6ea70f76 34 * $DragonFly: src/sys/kern/vfs_nlookup.c,v 1.21 2006/12/23 00:35:04 swildner Exp $
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35 */
36/*
37 * nlookup() is the 'new' namei interface. Rather then return directory and
38 * leaf vnodes (in various lock states) the new interface instead deals in
39 * namecache records. Namecache records may represent both a positive or
40 * a negative hit. The namespace is locked via the namecache record instead
41 * of via the vnode, and only the leaf namecache record (representing the
42 * filename) needs to be locked.
43 *
44 * This greatly improves filesystem parallelism and is a huge simplification
45 * of the API verses the old vnode locking / namei scheme.
46 *
47 * Filesystems must actively control the caching aspects of the namecache,
48 * and since namecache pointers are used as handles they are non-optional
49 * even for filesystems which do not generally wish to cache things. It is
50 * intended that a separate cache coherency API will be constructed to handle
51 * these issues.
52 */
53
54#include "opt_ktrace.h"
55
56#include <sys/param.h>
57#include <sys/systm.h>
58#include <sys/kernel.h>
59#include <sys/vnode.h>
60#include <sys/mount.h>
61#include <sys/filedesc.h>
62#include <sys/proc.h>
63#include <sys/namei.h>
64#include <sys/nlookup.h>
65#include <sys/malloc.h>
21739618 66#include <sys/stat.h>
70aac194 67#include <sys/objcache.h>
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68
69#ifdef KTRACE
70#include <sys/ktrace.h>
71#endif
72
73/*
74 * Initialize a nlookup() structure, early error return for copyin faults
75 * or a degenerate empty string (which is not allowed).
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76 *
77 * The first process proc0's credentials are used if the calling thread
78 * is not associated with a process context.
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79 */
80int
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81nlookup_init(struct nlookupdata *nd,
82 const char *path, enum uio_seg seg, int flags)
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83{
84 size_t pathlen;
85 struct proc *p;
86 thread_t td;
87 int error;
88
89 td = curthread;
90 p = td->td_proc;
91
92 /*
93 * note: the pathlen set by copy*str() includes the terminating \0.
94 */
95 bzero(nd, sizeof(struct nlookupdata));
70aac194 96 nd->nl_path = objcache_get(namei_oc, M_WAITOK);
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97 nd->nl_flags |= NLC_HASBUF;
98 if (seg == UIO_SYSSPACE)
99 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen);
100 else
101 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen);
102
103 /*
104 * Don't allow empty pathnames.
105 * POSIX.1 requirement: "" is not a vaild file name.
106 */
107 if (error == 0 && pathlen <= 1)
108 error = ENOENT;
109
110 if (error == 0) {
21739618 111 if (p && p->p_fd) {
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112 cache_copy(&p->p_fd->fd_ncdir, &nd->nl_nch);
113 cache_copy(&p->p_fd->fd_nrdir, &nd->nl_rootnch);
114 if (p->p_fd->fd_njdir.ncp)
115 cache_copy(&p->p_fd->fd_njdir, &nd->nl_jailnch);
21739618 116 nd->nl_cred = crhold(p->p_ucred);
690a3127 117 } else {
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118 cache_copy(&rootnch, &nd->nl_nch);
119 cache_copy(&nd->nl_nch, &nd->nl_rootnch);
120 cache_copy(&nd->nl_nch, &nd->nl_jailnch);
21739618 121 nd->nl_cred = crhold(proc0.p_ucred);
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122 }
123 nd->nl_td = td;
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124 nd->nl_flags |= flags;
125 } else {
126 nlookup_done(nd);
127 }
128 return(error);
129}
130
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131/*
132 * This works similarly to nlookup_init() but does not assume a process
28623bf9 133 * context. rootnch is always chosen for the root directory and the cred
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134 * and starting directory are supplied in arguments.
135 */
136int
137nlookup_init_raw(struct nlookupdata *nd,
138 const char *path, enum uio_seg seg, int flags,
28623bf9 139 struct ucred *cred, struct nchandle *ncstart)
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140{
141 size_t pathlen;
142 thread_t td;
143 int error;
144
145 td = curthread;
146
147 bzero(nd, sizeof(struct nlookupdata));
70aac194 148 nd->nl_path = objcache_get(namei_oc, M_WAITOK);
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149 nd->nl_flags |= NLC_HASBUF;
150 if (seg == UIO_SYSSPACE)
151 error = copystr(path, nd->nl_path, MAXPATHLEN, &pathlen);
152 else
153 error = copyinstr(path, nd->nl_path, MAXPATHLEN, &pathlen);
154
155 /*
156 * Don't allow empty pathnames.
157 * POSIX.1 requirement: "" is not a vaild file name.
158 */
159 if (error == 0 && pathlen <= 1)
160 error = ENOENT;
161
162 if (error == 0) {
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163 cache_copy(ncstart, &nd->nl_nch);
164 cache_copy(&rootnch, &nd->nl_rootnch);
165 cache_copy(&rootnch, &nd->nl_jailnch);
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166 nd->nl_cred = crhold(cred);
167 nd->nl_td = td;
168 nd->nl_flags |= flags;
169 } else {
170 nlookup_done(nd);
171 }
172 return(error);
173}
174
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175/*
176 * Set a different credential; this credential will be used by future
177 * operations performed on nd.nl_open_vp and nlookupdata structure.
178 */
179void
180nlookup_set_cred(struct nlookupdata *nd, struct ucred *cred)
181{
182 KKASSERT(nd->nl_cred != NULL);
183
184 if (nd->nl_cred != cred) {
185 cred = crhold(cred);
186 crfree(nd->nl_cred);
187 nd->nl_cred = cred;
188 }
189}
190
690a3127 191/*
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192 * Cleanup a nlookupdata structure after we are through with it. This may
193 * be called on any nlookupdata structure initialized with nlookup_init().
194 * Calling nlookup_done() is mandatory in all cases except where nlookup_init()
195 * returns an error, even if as a consumer you believe you have taken all
196 * dynamic elements out of the nlookupdata structure.
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197 */
198void
199nlookup_done(struct nlookupdata *nd)
200{
28623bf9 201 if (nd->nl_nch.ncp) {
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202 if (nd->nl_flags & NLC_NCPISLOCKED) {
203 nd->nl_flags &= ~NLC_NCPISLOCKED;
28623bf9 204 cache_unlock(&nd->nl_nch);
21739618 205 }
28623bf9 206 cache_drop(&nd->nl_nch);
690a3127 207 }
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208 if (nd->nl_rootnch.ncp)
209 cache_drop(&nd->nl_rootnch);
210 if (nd->nl_jailnch.ncp)
211 cache_drop(&nd->nl_jailnch);
690a3127 212 if ((nd->nl_flags & NLC_HASBUF) && nd->nl_path) {
70aac194 213 objcache_put(namei_oc, nd->nl_path);
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214 nd->nl_path = NULL;
215 }
216 if (nd->nl_cred) {
217 crfree(nd->nl_cred);
218 nd->nl_cred = NULL;
219 }
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220 if (nd->nl_open_vp) {
221 if (nd->nl_flags & NLC_LOCKVP) {
a11aaa81 222 vn_unlock(nd->nl_open_vp);
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223 nd->nl_flags &= ~NLC_LOCKVP;
224 }
87de5057 225 vn_close(nd->nl_open_vp, nd->nl_vp_fmode);
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226 nd->nl_open_vp = NULL;
227 }
228 nd->nl_flags = 0; /* clear remaining flags (just clear everything) */
229}
230
231void
232nlookup_zero(struct nlookupdata *nd)
233{
234 bzero(nd, sizeof(struct nlookupdata));
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235}
236
237/*
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238 * Simple all-in-one nlookup. Returns a locked namecache structure or NULL
239 * if an error occured.
240 *
241 * Note that the returned ncp is not checked for permissions, though VEXEC
242 * is checked on the directory path leading up to the result. The caller
243 * must call naccess() to check the permissions of the returned leaf.
690a3127 244 */
28623bf9 245struct nchandle
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246nlookup_simple(const char *str, enum uio_seg seg,
247 int niflags, int *error)
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248{
249 struct nlookupdata nd;
28623bf9 250 struct nchandle nch;
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251
252 *error = nlookup_init(&nd, str, seg, niflags);
253 if (*error == 0) {
21739618 254 if ((*error = nlookup(&nd)) == 0) {
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255 nch = nd.nl_nch; /* keep hold ref from structure */
256 cache_zero(&nd.nl_nch); /* and NULL out */
21739618 257 } else {
28623bf9 258 cache_zero(&nch);
21739618 259 }
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260 nlookup_done(&nd);
261 } else {
28623bf9 262 cache_zero(&nch);
690a3127 263 }
28623bf9 264 return(nch);
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265}
266
267/*
268 * Do a generic nlookup. Note that the passed nd is not nlookup_done()'d
269 * on return, even if an error occurs. If no error occurs the returned
28623bf9 270 * nl_nch is always referenced and locked, otherwise it may or may not be.
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271 *
272 * Intermediate directory elements, including the current directory, require
273 * execute (search) permission. nlookup does not examine the access
274 * permissions on the returned element.
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275 *
276 * If NLC_CREATE or NLC_DELETE is set the last directory must allow node
277 * creation (VCREATE/VDELETE), and an error code of 0 will be returned for
278 * a non-existant target. Otherwise a non-existant target will cause
279 * ENOENT to be returned.
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280 */
281int
282nlookup(struct nlookupdata *nd)
283{
284 struct nlcomponent nlc;
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285 struct nchandle nch;
286 struct mount *mp;
f4d4e93a 287 int wasdotordotdot;
690a3127 288 char *ptr;
fad57d0e 289 char *xptr;
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290 int error;
291 int len;
292
293#ifdef KTRACE
294 if (KTRPOINT(nd->nl_td, KTR_NAMEI))
a9b80e23 295 ktrnamei(nd->nl_td->td_proc, nd->nl_path);
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296#endif
297 bzero(&nlc, sizeof(nlc));
298
299 /*
300 * Setup for the loop. The current working namecache element must
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301 * be in a refd + unlocked state. This typically the case on entry except
302 * when stringing nlookup()'s along in a chain, since nlookup() always
28623bf9 303 * returns nl_nch in a locked state.
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304 */
305 nd->nl_loopcnt = 0;
306 if (nd->nl_flags & NLC_NCPISLOCKED) {
307 nd->nl_flags &= ~NLC_NCPISLOCKED;
28623bf9 308 cache_unlock(&nd->nl_nch);
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309 }
310 ptr = nd->nl_path;
311
312 /*
28623bf9 313 * Loop on the path components. At the top of the loop nd->nl_nch
524c845c 314 * is ref'd and unlocked and represents our current position.
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315 */
316 for (;;) {
317 /*
318 * Check if the root directory should replace the current
319 * directory. This is done at the start of a translation
320 * or after a symbolic link has been found. In other cases
321 * ptr will never be pointing at a '/'.
322 */
323 if (*ptr == '/') {
324 do {
325 ++ptr;
326 } while (*ptr == '/');
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327 cache_copy(&nd->nl_rootnch, &nch);
328 cache_drop(&nd->nl_nch);
329 nd->nl_nch = nch;
21739618 330 if (*ptr == 0) {
28623bf9 331 cache_lock(&nd->nl_nch);
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332 nd->nl_flags |= NLC_NCPISLOCKED;
333 error = 0;
334 break;
335 }
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336 continue;
337 }
338
21739618 339 /*
28623bf9 340 * Check directory search permissions.
21739618 341 */
28623bf9 342 if ((error = naccess(&nd->nl_nch, VEXEC, nd->nl_cred)) != 0)
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343 break;
344
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345 /*
346 * Extract the path component
347 */
348 nlc.nlc_nameptr = ptr;
349 while (*ptr && *ptr != '/')
350 ++ptr;
351 nlc.nlc_namelen = ptr - nlc.nlc_nameptr;
352
353 /*
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354 * Lookup the path component in the cache, creating an unresolved
355 * entry if necessary. We have to handle "." and ".." as special
356 * cases.
357 *
358 * When handling ".." we have to detect a traversal back through a
28623bf9 359 * mount point. If we are at the root, ".." just returns the root.
524c845c 360 *
28623bf9 361 * This subsection returns a locked, refd 'nch' unless it errors out.
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362 * The namecache topology is not allowed to be disconnected, so
363 * encountering a NULL parent will generate EINVAL. This typically
364 * occurs when a directory is removed out from under a process.
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365 *
366 * If NLC_DELETE is set neither '.' or '..' can be the last component
367 * of a path.
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368 */
369 if (nlc.nlc_namelen == 1 && nlc.nlc_nameptr[0] == '.') {
28623bf9 370 cache_get(&nd->nl_nch, &nch);
f4d4e93a 371 wasdotordotdot = 1;
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372 } else if (nlc.nlc_namelen == 2 &&
373 nlc.nlc_nameptr[0] == '.' && nlc.nlc_nameptr[1] == '.') {
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374 if (nd->nl_nch.mount == nd->nl_rootnch.mount &&
375 nd->nl_nch.ncp == nd->nl_rootnch.ncp
376 ) {
377 /*
378 * ".." at the root returns the root
379 */
380 cache_get(&nd->nl_nch, &nch);
21739618 381 } else {
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382 /*
383 * Locate the parent ncp. If we are at the root of a
384 * filesystem mount we have to skip to the mounted-on
385 * point in the underlying filesystem.
386 */
387 nch = nd->nl_nch;
388 while (nch.ncp == nch.mount->mnt_ncmountpt.ncp)
389 nch = nd->nl_nch.mount->mnt_ncmounton;
390 nch.ncp = nch.ncp->nc_parent;
391 KKASSERT(nch.ncp != NULL);
392 cache_get(&nch, &nch);
21739618 393 }
f4d4e93a 394 wasdotordotdot = 1;
21739618 395 } else {
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396 nch = cache_nlookup(&nd->nl_nch, &nlc);
397 while ((error = cache_resolve(&nch, nd->nl_cred)) == EAGAIN) {
6ea70f76 398 kprintf("[diagnostic] nlookup: relookup %*.*s\n",
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399 nch.ncp->nc_nlen, nch.ncp->nc_nlen, nch.ncp->nc_name);
400 cache_put(&nch);
401 nch = cache_nlookup(&nd->nl_nch, &nlc);
8e005a45 402 }
f4d4e93a 403 wasdotordotdot = 0;
21739618 404 }
524c845c 405 /*
28623bf9 406 * [end of subsection] ncp is locked and ref'd. nd->nl_nch is ref'd
524c845c 407 */
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408
409 /*
410 * Resolve the namespace if necessary. The ncp returned by
411 * cache_nlookup() is referenced and locked.
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412 *
413 * XXX neither '.' nor '..' should return EAGAIN since they were
414 * previously resolved and thus cannot be newly created ncp's.
690a3127 415 */
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416 if (nch.ncp->nc_flag & NCF_UNRESOLVED) {
417 error = cache_resolve(&nch, nd->nl_cred);
8e005a45 418 KKASSERT(error != EAGAIN);
690a3127 419 } else {
28623bf9 420 error = nch.ncp->nc_error;
690a3127 421 }
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422
423 /*
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424 * Early completion. ENOENT is not an error if this is the last
425 * component and NLC_CREATE was requested. Note that ncp->nc_error
426 * is left as ENOENT in that case, which we check later on.
f4d4e93a
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427 *
428 * Also handle invalid '.' or '..' components terminating a path
429 * during removal. The standard requires this and pax pretty
430 *stupidly depends on it.
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431 */
432 for (xptr = ptr; *xptr == '/'; ++xptr)
433 ;
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434 if (*xptr == 0) {
435 if (error == ENOENT && (nd->nl_flags & NLC_CREATE))
28623bf9 436 error = naccess(&nch, VCREATE, nd->nl_cred);
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437 if (error == 0 && wasdotordotdot && (nd->nl_flags & NLC_DELETE))
438 error = EINVAL;
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439 }
440
441 /*
442 * Early completion on error.
21739618 443 */
690a3127 444 if (error) {
28623bf9 445 cache_put(&nch);
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446 break;
447 }
448
449 /*
450 * If the element is a symlink and it is either not the last
451 * element or it is the last element and we are allowed to
452 * follow symlinks, resolve the symlink.
453 */
28623bf9 454 if ((nch.ncp->nc_flag & NCF_ISSYMLINK) &&
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455 (*ptr || (nd->nl_flags & NLC_FOLLOW))
456 ) {
457 if (nd->nl_loopcnt++ >= MAXSYMLINKS) {
21739618 458 error = ELOOP;
28623bf9 459 cache_put(&nch);
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460 break;
461 }
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462 error = nreadsymlink(nd, &nch, &nlc);
463 cache_put(&nch);
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464 if (error)
465 break;
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466
467 /*
468 * Concatenate trailing path elements onto the returned symlink.
469 * Note that if the path component (ptr) is not exhausted, it
470 * will being with a '/', so we do not have to add another one.
471 *
472 * The symlink may not be empty.
473 */
474 len = strlen(ptr);
475 if (nlc.nlc_namelen == 0 || nlc.nlc_namelen + len >= MAXPATHLEN) {
476 error = nlc.nlc_namelen ? ENAMETOOLONG : ENOENT;
70aac194 477 objcache_put(namei_oc, nlc.nlc_nameptr);
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478 break;
479 }
480 bcopy(ptr, nlc.nlc_nameptr + nlc.nlc_namelen, len + 1);
481 if (nd->nl_flags & NLC_HASBUF)
70aac194 482 objcache_put(namei_oc, nd->nl_path);
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483 nd->nl_path = nlc.nlc_nameptr;
484 nd->nl_flags |= NLC_HASBUF;
485 ptr = nd->nl_path;
486
487 /*
488 * Go back up to the top to resolve any initial '/'s in the
489 * symlink.
490 */
491 continue;
492 }
493
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494 /*
495 * If the element is a directory and we are crossing a mount point,
28623bf9 496 * Locate the mount.
21739618 497 */
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498 while ((nch.ncp->nc_flag & NCF_ISMOUNTPT) &&
499 (nd->nl_flags & NLC_NOCROSSMOUNT) == 0 &&
500 (mp = cache_findmount(&nch)) != NULL
21739618 501 ) {
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502 struct vnode *tdp;
503
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504 cache_put(&nch);
505 cache_get(&mp->mnt_ncmountpt, &nch);
21739618 506
28623bf9 507 if (nch.ncp->nc_flag & NCF_UNRESOLVED) {
f9642f56 508 while (vfs_busy(mp, 0))
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509 ;
510 error = VFS_ROOT(mp, &tdp);
f9642f56 511 vfs_unbusy(mp);
524c845c 512 if (error)
21739618 513 break;
28623bf9 514 cache_setvp(&nch, tdp);
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515 vput(tdp);
516 }
517 }
518 if (error) {
28623bf9 519 cache_put(&nch);
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520 break;
521 }
522
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523 /*
524 * Skip any slashes to get to the next element. If there
525 * are any slashes at all the current element must be a
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526 * directory or, in the create case, intended to become a directory.
527 * If it isn't we break without incrementing ptr and fall through
528 * to the failure case below.
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529 */
530 while (*ptr == '/') {
28623bf9 531 if ((nch.ncp->nc_flag & NCF_ISDIR) == 0 &&
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532 !(nd->nl_flags & NLC_WILLBEDIR)
533 ) {
690a3127 534 break;
fad57d0e 535 }
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536 ++ptr;
537 }
538
539 /*
540 * Continuation case: additional elements and the current
541 * element is a directory.
542 */
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543 if (*ptr && (nch.ncp->nc_flag & NCF_ISDIR)) {
544 cache_drop(&nd->nl_nch);
545 cache_unlock(&nch);
546 nd->nl_nch = nch;
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547 continue;
548 }
549
550 /*
551 * Failure case: additional elements and the current element
552 * is not a directory
553 */
554 if (*ptr) {
28623bf9 555 cache_put(&nch);
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556 error = ENOTDIR;
557 break;
558 }
559
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560 /*
561 * Successful lookup of last element.
562 *
563 * Check directory permissions if a deletion is specified.
564 */
565 if (*ptr == 0 && (nd->nl_flags & NLC_DELETE)) {
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566 if ((error = naccess(&nch, VDELETE, nd->nl_cred)) != 0) {
567 cache_put(&nch);
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568 break;
569 }
570 }
571
690a3127 572 /*
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573 * Termination: no more elements. If NLC_CREATE was set the
574 * ncp may represent a negative hit (ncp->nc_error will be ENOENT),
575 * but we still return an error code of 0.
690a3127 576 */
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577 cache_drop(&nd->nl_nch);
578 nd->nl_nch = nch;
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579 nd->nl_flags |= NLC_NCPISLOCKED;
580 error = 0;
581 break;
582 }
583 return(error);
584}
585
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586/*
587 * Resolve a mount point's glue ncp. This ncp connects creates the illusion
588 * of continuity in the namecache tree by connecting the ncp related to the
589 * vnode under the mount to the ncp related to the mount's root vnode.
590 *
591 * If no error occured a locked, ref'd ncp is stored in *ncpp.
592 */
593int
28623bf9 594nlookup_mp(struct mount *mp, struct nchandle *nch)
21739618 595{
21739618
MD
596 struct vnode *vp;
597 int error;
598
599 error = 0;
28623bf9
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600 cache_get(&mp->mnt_ncmountpt, nch);
601 if (nch->ncp->nc_flag & NCF_UNRESOLVED) {
f9642f56 602 while (vfs_busy(mp, 0))
21739618
MD
603 ;
604 error = VFS_ROOT(mp, &vp);
f9642f56 605 vfs_unbusy(mp);
21739618 606 if (error) {
28623bf9 607 cache_put(nch);
21739618 608 } else {
28623bf9 609 cache_setvp(nch, vp);
21739618
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610 vput(vp);
611 }
612 }
21739618
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613 return(error);
614}
615
690a3127
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616/*
617 * Read the contents of a symlink, allocate a path buffer out of the
70aac194 618 * namei_oc and initialize the supplied nlcomponent with the result.
690a3127
MD
619 *
620 * If an error occurs no buffer will be allocated or returned in the nlc.
621 */
622int
28623bf9 623nreadsymlink(struct nlookupdata *nd, struct nchandle *nch,
690a3127
MD
624 struct nlcomponent *nlc)
625{
21739618 626 struct vnode *vp;
690a3127
MD
627 struct iovec aiov;
628 struct uio auio;
629 int linklen;
630 int error;
631 char *cp;
632
633 nlc->nlc_nameptr = NULL;
634 nlc->nlc_namelen = 0;
28623bf9 635 if (nch->ncp->nc_vp == NULL)
690a3127 636 return(ENOENT);
28623bf9 637 if ((error = cache_vget(nch, nd->nl_cred, LK_SHARED, &vp)) != 0)
690a3127 638 return(error);
70aac194 639 cp = objcache_get(namei_oc, M_WAITOK);
690a3127
MD
640 aiov.iov_base = cp;
641 aiov.iov_len = MAXPATHLEN;
642 auio.uio_iov = &aiov;
643 auio.uio_iovcnt = 1;
644 auio.uio_offset = 0;
645 auio.uio_rw = UIO_READ;
646 auio.uio_segflg = UIO_SYSSPACE;
647 auio.uio_td = nd->nl_td;
648 auio.uio_resid = MAXPATHLEN - 1;
21739618 649 error = VOP_READLINK(vp, &auio, nd->nl_cred);
690a3127
MD
650 if (error)
651 goto fail;
21739618 652 linklen = MAXPATHLEN - 1 - auio.uio_resid;
690a3127
MD
653 if (varsym_enable) {
654 linklen = varsymreplace(cp, linklen, MAXPATHLEN - 1);
655 if (linklen < 0) {
656 error = ENAMETOOLONG;
657 goto fail;
658 }
659 }
660 cp[linklen] = 0;
661 nlc->nlc_nameptr = cp;
662 nlc->nlc_namelen = linklen;
21739618 663 vput(vp);
690a3127
MD
664 return(0);
665fail:
70aac194 666 objcache_put(namei_oc, cp);
21739618 667 vput(vp);
690a3127
MD
668 return(error);
669}
670
21739618
MD
671/*
672 * Check access [XXX cache vattr!] [XXX quota]
673 *
674 * Generally check the V* access bits from sys/vnode.h. All specified bits
675 * must pass for this function to return 0.
676 *
677 * If VCREATE is specified and the target ncp represents a non-existant
678 * file or dir, or if VDELETE is specified and the target exists, the parent
679 * directory is checked for VWRITE. If VEXCL is specified and the target
680 * ncp represents a positive hit, an error is returned.
681 *
682 * If VCREATE is not specified and the target does not exist (negative hit),
683 * ENOENT is returned. Note that nlookup() does not (and should not) return
684 * ENOENT for non-existant leafs.
685 *
686 * The passed ncp may or may not be locked. The caller should use a
687 * locked ncp on leaf lookups, especially for VCREATE, VDELETE, and VEXCL
688 * checks.
689 */
690int
28623bf9 691naccess(struct nchandle *nch, int vmode, struct ucred *cred)
21739618 692{
28623bf9 693 struct nchandle par;
21739618
MD
694 struct vnode *vp;
695 struct vattr va;
696 int error;
697
28623bf9
MD
698 if (nch->ncp->nc_flag & NCF_UNRESOLVED) {
699 cache_lock(nch);
700 cache_resolve(nch, cred);
701 cache_unlock(nch);
21739618 702 }
28623bf9 703 error = nch->ncp->nc_error;
21739618 704 if (vmode & (VDELETE|VCREATE|VEXCL)) {
28623bf9
MD
705 if (((vmode & VCREATE) && nch->ncp->nc_vp == NULL) ||
706 ((vmode & VDELETE) && nch->ncp->nc_vp != NULL)
21739618 707 ) {
28623bf9 708 if ((par.ncp = nch->ncp->nc_parent) == NULL) {
8e005a45 709 if (error != EAGAIN)
fad57d0e 710 error = EINVAL;
8e005a45 711 } else {
28623bf9
MD
712 par.mount = nch->mount;
713 cache_hold(&par);
714 error = naccess(&par, VWRITE, cred);
715 cache_drop(&par);
8e005a45 716 }
21739618 717 }
28623bf9 718 if ((vmode & VEXCL) && nch->ncp->nc_vp != NULL)
21739618
MD
719 error = EEXIST;
720 }
721 if (error == 0) {
28623bf9 722 error = cache_vget(nch, cred, LK_SHARED, &vp);
21739618
MD
723 if (error == ENOENT) {
724 if (vmode & VCREATE)
725 error = 0;
726 } else if (error == 0) {
727 /* XXX cache the va in the namecache or in the vnode */
87de5057 728 if ((error = VOP_GETATTR(vp, &va)) == 0) {
21739618
MD
729 if ((vmode & VWRITE) && vp->v_mount) {
730 if (vp->v_mount->mnt_flag & MNT_RDONLY)
731 error = EROFS;
732 }
733 }
734 vput(vp);
735 if (error == 0)
736 error = naccess_va(&va, vmode, cred);
737 }
738 }
739 return(error);
740}
741
742/*
743 * Check the requested access against the given vattr using cred.
744 */
745int
746naccess_va(struct vattr *va, int vmode, struct ucred *cred)
747{
748 int i;
749
750 /*
751 * Test the immutable bit for files, directories, and softlinks.
752 */
753 if (vmode & (VWRITE|VDELETE)) {
754 if (va->va_type == VDIR || va->va_type == VLNK || va->va_type == VREG) {
755 if (va->va_flags & IMMUTABLE)
756 return (EPERM);
757 }
758 }
759
760 /*
761 * root gets universal access
762 */
763 if (cred->cr_uid == 0)
764 return(0);
765
766 /*
767 * Check owner perms, group perms, and world perms
768 */
769 vmode &= S_IRWXU;
770 if (cred->cr_uid == va->va_uid) {
771 if ((vmode & va->va_mode) != vmode)
772 return(EACCES);
773 return(0);
774 }
775
776 vmode >>= 3;
777 for (i = 0; i < cred->cr_ngroups; ++i) {
778 if (va->va_gid == cred->cr_groups[i]) {
779 if ((vmode & va->va_mode) != vmode)
780 return(EACCES);
781 return(0);
782 }
783 }
784
785 vmode >>= 3;
786 if ((vmode & va->va_mode) != vmode)
787 return(EACCES);
788 return(0);
789}
790