Annotation of src/sys/kern/vfs_lookup.c, Revision 1.56
1.56 ! perry 1: /* $NetBSD: vfs_lookup.c,v 1.55 2004/09/17 14:11:25 skrll Exp $ */
1.13 cgd 2:
1.10 cgd 3: /*
1.12 mycroft 4: * Copyright (c) 1982, 1986, 1989, 1993
5: * The Regents of the University of California. All rights reserved.
1.10 cgd 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.
1.49 agc 20: * 3. Neither the name of the University nor the names of its contributors
1.10 cgd 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: *
1.26 fvdl 36: * @(#)vfs_lookup.c 8.10 (Berkeley) 5/27/95
1.10 cgd 37: */
1.38 lukem 38:
39: #include <sys/cdefs.h>
1.56 ! perry 40: __KERNEL_RCSID(0, "$NetBSD: vfs_lookup.c,v 1.55 2004/09/17 14:11:25 skrll Exp $");
1.27 thorpej 41:
42: #include "opt_ktrace.h"
1.50 cb 43: #include "opt_systrace.h"
1.10 cgd 44:
45: #include <sys/param.h>
1.15 cgd 46: #include <sys/systm.h>
1.10 cgd 47: #include <sys/syslimits.h>
48: #include <sys/time.h>
49: #include <sys/namei.h>
50: #include <sys/vnode.h>
51: #include <sys/mount.h>
52: #include <sys/errno.h>
1.39 lukem 53: #include <sys/filedesc.h>
54: #include <sys/hash.h>
1.10 cgd 55: #include <sys/malloc.h>
56: #include <sys/proc.h>
1.40 wrstuden 57: #include <sys/syslog.h>
1.12 mycroft 58:
1.10 cgd 59: #ifdef KTRACE
60: #include <sys/ktrace.h>
61: #endif
1.50 cb 62: #ifdef SYSTRACE
63: #include <sys/systrace.h>
64: #endif
1.16 christos 65:
1.35 thorpej 66: struct pool pnbuf_pool; /* pathname buffer pool */
1.37 thorpej 67: struct pool_cache pnbuf_cache; /* pathname buffer cache */
1.44 thorpej 68:
69: MALLOC_DEFINE(M_NAMEI, "namei", "namei path buffer");
1.35 thorpej 70:
1.10 cgd 71: /*
72: * Convert a pathname into a pointer to a locked inode.
73: *
74: * The FOLLOW flag is set when symbolic links are to be followed
75: * when they occur at the end of the name translation process.
76: * Symbolic links are always followed for all other pathname
77: * components other than the last.
78: *
79: * The segflg defines whether the name is to be copied from user
80: * space or kernel space.
81: *
82: * Overall outline of namei:
83: *
84: * copy in name
85: * get starting directory
86: * while (!done && !error) {
87: * call lookup to search path.
88: * if symbolic link, massage name in buffer and continue
89: * }
90: */
1.12 mycroft 91: int
92: namei(ndp)
1.33 augustss 93: struct nameidata *ndp;
1.10 cgd 94: {
1.30 thorpej 95: struct cwdinfo *cwdi; /* pointer to cwd state */
1.33 augustss 96: char *cp; /* pointer into pathname argument */
97: struct vnode *dp; /* the directory we are searching */
1.10 cgd 98: struct iovec aiov; /* uio for reading symbolic links */
99: struct uio auio;
1.23 mycroft 100: int error, linklen;
1.12 mycroft 101: struct componentname *cnp = &ndp->ni_cnd;
1.10 cgd 102:
1.12 mycroft 103: #ifdef DIAGNOSTIC
1.48 fvdl 104: if (!cnp->cn_cred || !cnp->cn_proc)
1.12 mycroft 105: panic ("namei: bad cred/proc");
106: if (cnp->cn_nameiop & (~OPMASK))
107: panic ("namei: nameiop contaminated with flags");
108: if (cnp->cn_flags & OPMASK)
109: panic ("namei: flags contaminated with nameiops");
110: #endif
1.48 fvdl 111: cwdi = cnp->cn_proc->p_cwdi;
1.10 cgd 112:
113: /*
114: * Get a buffer for the name to be translated, and copy the
115: * name into the buffer.
116: */
1.12 mycroft 117: if ((cnp->cn_flags & HASBUF) == 0)
1.35 thorpej 118: cnp->cn_pnbuf = PNBUF_GET();
1.10 cgd 119: if (ndp->ni_segflg == UIO_SYSSPACE)
1.12 mycroft 120: error = copystr(ndp->ni_dirp, cnp->cn_pnbuf,
1.10 cgd 121: MAXPATHLEN, &ndp->ni_pathlen);
122: else
1.12 mycroft 123: error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
1.10 cgd 124: MAXPATHLEN, &ndp->ni_pathlen);
1.21 kleink 125:
126: /*
127: * POSIX.1 requirement: "" is not a valid file name.
1.56 ! perry 128: */
1.21 kleink 129: if (!error && ndp->ni_pathlen == 1)
130: error = ENOENT;
131:
1.10 cgd 132: if (error) {
1.35 thorpej 133: PNBUF_PUT(cnp->cn_pnbuf);
1.10 cgd 134: ndp->ni_vp = NULL;
135: return (error);
136: }
137: ndp->ni_loopcnt = 0;
1.21 kleink 138:
1.10 cgd 139: #ifdef KTRACE
1.48 fvdl 140: if (KTRPOINT(cnp->cn_proc, KTR_NAMEI))
141: ktrnamei(cnp->cn_proc, cnp->cn_pnbuf);
1.50 cb 142: #endif
143: #ifdef SYSTRACE
144: if (ISSET(cnp->cn_proc->p_flag, P_SYSTRACE))
145: systrace_namei(ndp);
1.10 cgd 146: #endif
147:
148: /*
149: * Get starting point for the translation.
150: */
1.30 thorpej 151: if ((ndp->ni_rootdir = cwdi->cwdi_rdir) == NULL)
1.11 cgd 152: ndp->ni_rootdir = rootvnode;
1.23 mycroft 153: /*
154: * Check if starting from root directory or current directory.
155: */
156: if (cnp->cn_pnbuf[0] == '/') {
157: dp = ndp->ni_rootdir;
158: VREF(dp);
159: } else {
1.30 thorpej 160: dp = cwdi->cwdi_cdir;
1.23 mycroft 161: VREF(dp);
162: }
1.10 cgd 163: for (;;) {
1.45 erh 164: if (!dp->v_mount)
165: {
166: /* Give up if the directory is no longer mounted */
167: PNBUF_PUT(cnp->cn_pnbuf);
168: return (ENOENT);
169: }
1.12 mycroft 170: cnp->cn_nameptr = cnp->cn_pnbuf;
1.10 cgd 171: ndp->ni_startdir = dp;
1.16 christos 172: if ((error = lookup(ndp)) != 0) {
1.35 thorpej 173: PNBUF_PUT(cnp->cn_pnbuf);
1.10 cgd 174: return (error);
175: }
176: /*
177: * Check for symbolic link
178: */
1.12 mycroft 179: if ((cnp->cn_flags & ISSYMLINK) == 0) {
180: if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0)
1.35 thorpej 181: PNBUF_PUT(cnp->cn_pnbuf);
1.10 cgd 182: else
1.12 mycroft 183: cnp->cn_flags |= HASBUF;
1.10 cgd 184: return (0);
185: }
1.29 wrstuden 186: if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
1.26 fvdl 187: VOP_UNLOCK(ndp->ni_dvp, 0);
1.10 cgd 188: if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
189: error = ELOOP;
190: break;
191: }
1.25 enami 192: if (ndp->ni_vp->v_mount->mnt_flag & MNT_SYMPERM) {
193: error = VOP_ACCESS(ndp->ni_vp, VEXEC, cnp->cn_cred,
1.48 fvdl 194: cnp->cn_proc);
1.25 enami 195: if (error != 0)
196: break;
197: }
1.10 cgd 198: if (ndp->ni_pathlen > 1)
1.35 thorpej 199: cp = PNBUF_GET();
1.10 cgd 200: else
1.12 mycroft 201: cp = cnp->cn_pnbuf;
1.10 cgd 202: aiov.iov_base = cp;
203: aiov.iov_len = MAXPATHLEN;
204: auio.uio_iov = &aiov;
205: auio.uio_iovcnt = 1;
206: auio.uio_offset = 0;
207: auio.uio_rw = UIO_READ;
208: auio.uio_segflg = UIO_SYSSPACE;
1.55 skrll 209: auio.uio_procp = NULL;
1.10 cgd 210: auio.uio_resid = MAXPATHLEN;
1.16 christos 211: error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred);
212: if (error) {
1.23 mycroft 213: badlink:
1.10 cgd 214: if (ndp->ni_pathlen > 1)
1.35 thorpej 215: PNBUF_PUT(cp);
1.10 cgd 216: break;
217: }
218: linklen = MAXPATHLEN - auio.uio_resid;
1.23 mycroft 219: if (linklen == 0) {
220: error = ENOENT;
221: goto badlink;
222: }
1.10 cgd 223: if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
224: error = ENAMETOOLONG;
1.23 mycroft 225: goto badlink;
1.10 cgd 226: }
227: if (ndp->ni_pathlen > 1) {
1.28 perry 228: memcpy(cp + linklen, ndp->ni_next, ndp->ni_pathlen);
1.35 thorpej 229: PNBUF_PUT(cnp->cn_pnbuf);
1.12 mycroft 230: cnp->cn_pnbuf = cp;
1.10 cgd 231: } else
1.12 mycroft 232: cnp->cn_pnbuf[linklen] = '\0';
1.10 cgd 233: ndp->ni_pathlen += linklen;
234: vput(ndp->ni_vp);
235: dp = ndp->ni_dvp;
1.23 mycroft 236: /*
237: * Check if root directory should replace current directory.
238: */
239: if (cnp->cn_pnbuf[0] == '/') {
240: vrele(dp);
241: dp = ndp->ni_rootdir;
242: VREF(dp);
243: }
1.10 cgd 244: }
1.35 thorpej 245: PNBUF_PUT(cnp->cn_pnbuf);
1.10 cgd 246: vrele(ndp->ni_dvp);
247: vput(ndp->ni_vp);
248: ndp->ni_vp = NULL;
249: return (error);
250: }
251:
252: /*
1.39 lukem 253: * Determine the namei hash (for cn_hash) for name.
254: * If *ep != NULL, hash from name to ep-1.
255: * If *ep == NULL, hash from name until the first NUL or '/', and
256: * return the location of this termination character in *ep.
257: *
258: * This function returns an equivalent hash to the MI hash32_strn().
259: * The latter isn't used because in the *ep == NULL case, determining
260: * the length of the string to the first NUL or `/' and then calling
261: * hash32_strn() involves unnecessary double-handling of the data.
262: */
263: uint32_t
264: namei_hash(const char *name, const char **ep)
265: {
266: uint32_t hash;
267:
268: hash = HASH32_STR_INIT;
269: if (*ep != NULL) {
270: for (; name < *ep; name++)
271: hash = hash * 33 + *(uint8_t *)name;
272: } else {
273: for (; *name != '\0' && *name != '/'; name++)
274: hash = hash * 33 + *(uint8_t *)name;
275: *ep = name;
276: }
277: return (hash + (hash >> 5));
278: }
279:
280: /*
1.10 cgd 281: * Search a pathname.
282: * This is a very central and rather complicated routine.
283: *
284: * The pathname is pointed to by ni_ptr and is of length ni_pathlen.
285: * The starting directory is taken from ni_startdir. The pathname is
286: * descended until done, or a symbolic link is encountered. The variable
287: * ni_more is clear if the path is completed; it is set to one if a
288: * symbolic link needing interpretation is encountered.
289: *
290: * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on
291: * whether the name is to be looked up, created, renamed, or deleted.
292: * When CREATE, RENAME, or DELETE is specified, information usable in
293: * creating, renaming, or deleting a directory entry may be calculated.
294: * If flag has LOCKPARENT or'ed into it, the parent directory is returned
295: * locked. If flag has WANTPARENT or'ed into it, the parent directory is
296: * returned unlocked. Otherwise the parent directory is not returned. If
297: * the target of the pathname exists and LOCKLEAF is or'ed into the flag
298: * the target is returned locked, otherwise it is returned unlocked.
299: * When creating or renaming and LOCKPARENT is specified, the target may not
300: * be ".". When deleting and LOCKPARENT is specified, the target may be ".".
1.56 ! perry 301: *
1.10 cgd 302: * Overall outline of lookup:
303: *
304: * dirloop:
305: * identify next component of name at ndp->ni_ptr
306: * handle degenerate case where name is null string
307: * if .. and crossing mount points and on mounted filesys, find parent
308: * call VOP_LOOKUP routine for next component name
309: * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set
310: * component vnode returned in ni_vp (if it exists), locked.
311: * if result vnode is mounted on and crossing mount points,
312: * find mounted on vnode
313: * if more components of name, do next level at dirloop
314: * return the answer in ni_vp, locked if LOCKLEAF set
315: * if LOCKPARENT set, return locked parent in ni_dvp
316: * if WANTPARENT set, return unlocked parent in ni_dvp
317: */
1.12 mycroft 318: int
319: lookup(ndp)
1.33 augustss 320: struct nameidata *ndp;
1.10 cgd 321: {
1.33 augustss 322: const char *cp; /* pointer into pathname argument */
323: struct vnode *dp = 0; /* the directory we are searching */
1.10 cgd 324: struct vnode *tdp; /* saved dp */
325: struct mount *mp; /* mount table entry */
326: int docache; /* == 0 do not cache last component */
327: int wantparent; /* 1 => wantparent or lockparent flag */
1.12 mycroft 328: int rdonly; /* lookup read-only flag bit */
1.10 cgd 329: int error = 0;
1.23 mycroft 330: int slashes;
1.32 wrstuden 331: int dpunlocked = 0; /* dp has already been unlocked */
1.12 mycroft 332: struct componentname *cnp = &ndp->ni_cnd;
1.10 cgd 333:
334: /*
335: * Setup: break out flag bits into variables.
336: */
1.12 mycroft 337: wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
338: docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE;
339: if (cnp->cn_nameiop == DELETE ||
340: (wantparent && cnp->cn_nameiop != CREATE))
1.10 cgd 341: docache = 0;
1.12 mycroft 342: rdonly = cnp->cn_flags & RDONLY;
1.10 cgd 343: ndp->ni_dvp = NULL;
1.12 mycroft 344: cnp->cn_flags &= ~ISSYMLINK;
1.10 cgd 345: dp = ndp->ni_startdir;
346: ndp->ni_startdir = NULLVP;
1.26 fvdl 347: vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
1.10 cgd 348:
1.23 mycroft 349: /*
350: * If we have a leading string of slashes, remove them, and just make
351: * sure the current node is a directory.
352: */
353: cp = cnp->cn_nameptr;
354: if (*cp == '/') {
355: do {
356: cp++;
357: } while (*cp == '/');
358: ndp->ni_pathlen -= cp - cnp->cn_nameptr;
359: cnp->cn_nameptr = cp;
360:
361: if (dp->v_type != VDIR) {
362: error = ENOTDIR;
363: goto bad;
364: }
365:
366: /*
367: * If we've exhausted the path name, then just return the
368: * current node. If the caller requested the parent node (i.e.
369: * it's a CREATE, DELETE, or RENAME), and we don't have one
370: * (because this is the root directory), then we must fail.
371: */
372: if (cnp->cn_nameptr[0] == '\0') {
373: if (ndp->ni_dvp == NULL && wantparent) {
374: error = EISDIR;
375: goto bad;
376: }
377: ndp->ni_vp = dp;
378: cnp->cn_flags |= ISLASTCN;
379: goto terminal;
380: }
381: }
382:
1.10 cgd 383: dirloop:
384: /*
385: * Search a new directory.
386: *
1.12 mycroft 387: * The cn_hash value is for use by vfs_cache.
1.10 cgd 388: * The last component of the filename is left accessible via
1.12 mycroft 389: * cnp->cn_nameptr for callers that need the name. Callers needing
1.10 cgd 390: * the name set the SAVENAME flag. When done, they assume
391: * responsibility for freeing the pathname buffer.
392: */
1.12 mycroft 393: cnp->cn_consume = 0;
1.39 lukem 394: cp = NULL;
395: cnp->cn_hash = namei_hash(cnp->cn_nameptr, &cp);
1.12 mycroft 396: cnp->cn_namelen = cp - cnp->cn_nameptr;
397: if (cnp->cn_namelen > NAME_MAX) {
1.10 cgd 398: error = ENAMETOOLONG;
399: goto bad;
400: }
401: #ifdef NAMEI_DIAGNOSTIC
402: { char c = *cp;
1.41 soren 403: *(char *)cp = '\0';
1.19 christos 404: printf("{%s}: ", cnp->cn_nameptr);
1.41 soren 405: *(char *)cp = c; }
1.52 yamt 406: #endif /* NAMEI_DIAGNOSTIC */
1.12 mycroft 407: ndp->ni_pathlen -= cnp->cn_namelen;
1.10 cgd 408: ndp->ni_next = cp;
1.23 mycroft 409: /*
410: * If this component is followed by a slash, then move the pointer to
411: * the next component forward, and remember that this component must be
412: * a directory.
413: */
414: if (*cp == '/') {
415: do {
416: cp++;
417: } while (*cp == '/');
418: slashes = cp - ndp->ni_next;
419: ndp->ni_pathlen -= slashes;
420: ndp->ni_next = cp;
421: cnp->cn_flags |= REQUIREDIR;
422: } else {
423: slashes = 0;
424: cnp->cn_flags &= ~REQUIREDIR;
425: }
426: /*
427: * We do special processing on the last component, whether or not it's
428: * a directory. Cache all intervening lookups, but not the final one.
429: */
430: if (*cp == '\0') {
431: if (docache)
432: cnp->cn_flags |= MAKEENTRY;
433: else
434: cnp->cn_flags &= ~MAKEENTRY;
435: cnp->cn_flags |= ISLASTCN;
436: } else {
437: cnp->cn_flags |= MAKEENTRY;
438: cnp->cn_flags &= ~ISLASTCN;
439: }
1.12 mycroft 440: if (cnp->cn_namelen == 2 &&
441: cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
442: cnp->cn_flags |= ISDOTDOT;
443: else
444: cnp->cn_flags &= ~ISDOTDOT;
1.10 cgd 445:
446: /*
447: * Handle "..": two special cases.
448: * 1. If at root directory (e.g. after chroot)
1.12 mycroft 449: * or at absolute root directory
1.10 cgd 450: * then ignore it so can't get out.
1.40 wrstuden 451: * 1a. If we have somehow gotten out of a jail, warn
452: * and also ignore it so we can't get farther out.
1.10 cgd 453: * 2. If this vnode is the root of a mounted
454: * filesystem, then replace it with the
455: * vnode which was mounted on so we take the
456: * .. in the other file system.
457: */
1.12 mycroft 458: if (cnp->cn_flags & ISDOTDOT) {
1.10 cgd 459: for (;;) {
1.12 mycroft 460: if (dp == ndp->ni_rootdir || dp == rootvnode) {
1.10 cgd 461: ndp->ni_dvp = dp;
462: ndp->ni_vp = dp;
463: VREF(dp);
464: goto nextname;
1.40 wrstuden 465: }
466: if (ndp->ni_rootdir != rootvnode) {
467: int retval;
468: VOP_UNLOCK(dp, 0);
1.48 fvdl 469: retval = vn_isunder(dp, ndp->ni_rootdir,
470: cnp->cn_proc);
1.40 wrstuden 471: vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
472: if (!retval) {
473: /* Oops! We got out of jail! */
474: log(LOG_WARNING,
475: "chrooted pid %d uid %d (%s) "
476: "detected outside of its chroot\n",
1.48 fvdl 477: cnp->cn_proc->p_pid,
478: cnp->cn_proc->p_ucred->cr_uid,
479: cnp->cn_proc->p_comm);
1.40 wrstuden 480: /* Put us at the jail root. */
481: vput(dp);
482: dp = ndp->ni_rootdir;
483: ndp->ni_dvp = dp;
484: ndp->ni_vp = dp;
485: VREF(dp);
486: VREF(dp);
487: vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
488: goto nextname;
489: }
1.10 cgd 490: }
491: if ((dp->v_flag & VROOT) == 0 ||
1.12 mycroft 492: (cnp->cn_flags & NOCROSSMOUNT))
1.10 cgd 493: break;
494: tdp = dp;
495: dp = dp->v_mount->mnt_vnodecovered;
496: vput(tdp);
497: VREF(dp);
1.26 fvdl 498: vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
1.10 cgd 499: }
500: }
501:
502: /*
503: * We now have a segment name to search for, and a directory to search.
504: */
1.12 mycroft 505: unionlookup:
506: ndp->ni_dvp = dp;
1.26 fvdl 507: ndp->ni_vp = NULL;
1.31 wrstuden 508: cnp->cn_flags &= ~PDIRUNLOCK;
1.16 christos 509: if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) {
1.10 cgd 510: #ifdef DIAGNOSTIC
511: if (ndp->ni_vp != NULL)
1.43 christos 512: panic("leaf `%s' should be empty", cnp->cn_nameptr);
1.52 yamt 513: #endif /* DIAGNOSTIC */
1.10 cgd 514: #ifdef NAMEI_DIAGNOSTIC
1.19 christos 515: printf("not found\n");
1.52 yamt 516: #endif /* NAMEI_DIAGNOSTIC */
1.12 mycroft 517: if ((error == ENOENT) &&
1.10 cgd 518: (dp->v_flag & VROOT) &&
519: (dp->v_mount->mnt_flag & MNT_UNION)) {
520: tdp = dp;
521: dp = dp->v_mount->mnt_vnodecovered;
1.31 wrstuden 522: if (cnp->cn_flags & PDIRUNLOCK)
523: vrele(tdp);
524: else
525: vput(tdp);
1.10 cgd 526: VREF(dp);
1.26 fvdl 527: vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
1.12 mycroft 528: goto unionlookup;
1.10 cgd 529: }
1.12 mycroft 530:
1.10 cgd 531: if (error != EJUSTRETURN)
532: goto bad;
533: /*
1.23 mycroft 534: * If this was not the last component, or there were trailing
1.51 christos 535: * slashes, and we are not going to create a directory,
536: * then the name must exist.
1.23 mycroft 537: */
1.51 christos 538: if ((cnp->cn_flags & (REQUIREDIR | CREATEDIR)) == REQUIREDIR) {
1.23 mycroft 539: error = ENOENT;
540: goto bad;
541: }
542: /*
1.10 cgd 543: * If creating and at end of pathname, then can consider
544: * allowing file to be created.
545: */
1.26 fvdl 546: if (rdonly) {
1.10 cgd 547: error = EROFS;
548: goto bad;
549: }
550: /*
551: * We return with ni_vp NULL to indicate that the entry
552: * doesn't currently exist, leaving a pointer to the
553: * (possibly locked) directory inode in ndp->ni_dvp.
554: */
1.12 mycroft 555: if (cnp->cn_flags & SAVESTART) {
1.10 cgd 556: ndp->ni_startdir = ndp->ni_dvp;
557: VREF(ndp->ni_startdir);
558: }
559: return (0);
560: }
561: #ifdef NAMEI_DIAGNOSTIC
1.19 christos 562: printf("found\n");
1.52 yamt 563: #endif /* NAMEI_DIAGNOSTIC */
1.10 cgd 564:
1.12 mycroft 565: /*
1.23 mycroft 566: * Take into account any additional components consumed by the
567: * underlying filesystem. This will include any trailing slashes after
568: * the last component consumed.
1.12 mycroft 569: */
570: if (cnp->cn_consume > 0) {
1.23 mycroft 571: ndp->ni_pathlen -= cnp->cn_consume - slashes;
572: ndp->ni_next += cnp->cn_consume - slashes;
1.12 mycroft 573: cnp->cn_consume = 0;
1.23 mycroft 574: if (ndp->ni_next[0] == '\0')
575: cnp->cn_flags |= ISLASTCN;
1.12 mycroft 576: }
577:
1.10 cgd 578: dp = ndp->ni_vp;
579: /*
580: * Check to see if the vnode has been mounted on;
581: * if so find the root of the mounted file system.
582: */
583: while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
1.12 mycroft 584: (cnp->cn_flags & NOCROSSMOUNT) == 0) {
1.26 fvdl 585: if (vfs_busy(mp, 0, 0))
1.12 mycroft 586: continue;
1.32 wrstuden 587: VOP_UNLOCK(dp, 0);
1.47 thorpej 588: error = VFS_ROOT(mp, &tdp);
1.26 fvdl 589: vfs_unbusy(mp);
1.32 wrstuden 590: if (error) {
591: dpunlocked = 1;
1.10 cgd 592: goto bad2;
1.32 wrstuden 593: }
594: vrele(dp);
1.10 cgd 595: ndp->ni_vp = dp = tdp;
1.14 mycroft 596: }
597:
598: /*
1.23 mycroft 599: * Check for symbolic link. Back up over any slashes that we skipped,
600: * as we will need them again.
1.14 mycroft 601: */
1.23 mycroft 602: if ((dp->v_type == VLNK) && (cnp->cn_flags & (FOLLOW|REQUIREDIR))) {
603: ndp->ni_pathlen += slashes;
604: ndp->ni_next -= slashes;
1.14 mycroft 605: cnp->cn_flags |= ISSYMLINK;
606: return (0);
1.10 cgd 607: }
608:
1.23 mycroft 609: /*
610: * Check for directory, if the component was followed by a series of
611: * slashes.
612: */
613: if ((dp->v_type != VDIR) && (cnp->cn_flags & REQUIREDIR)) {
614: error = ENOTDIR;
615: goto bad2;
616: }
617:
1.10 cgd 618: nextname:
619: /*
1.23 mycroft 620: * Not a symbolic link. If this was not the last component, then
621: * continue at the next component, else return.
1.10 cgd 622: */
1.23 mycroft 623: if (!(cnp->cn_flags & ISLASTCN)) {
1.12 mycroft 624: cnp->cn_nameptr = ndp->ni_next;
1.10 cgd 625: vrele(ndp->ni_dvp);
626: goto dirloop;
627: }
1.23 mycroft 628:
629: terminal:
1.10 cgd 630: /*
1.26 fvdl 631: * Disallow directory write attempts on read-only file systems.
1.10 cgd 632: */
1.26 fvdl 633: if (rdonly &&
634: (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
1.10 cgd 635: /*
636: * Disallow directory write attempts on read-only
637: * file systems.
638: */
1.26 fvdl 639: error = EROFS;
640: goto bad2;
1.10 cgd 641: }
1.23 mycroft 642: if (ndp->ni_dvp != NULL) {
643: if (cnp->cn_flags & SAVESTART) {
644: ndp->ni_startdir = ndp->ni_dvp;
645: VREF(ndp->ni_startdir);
646: }
647: if (!wantparent)
648: vrele(ndp->ni_dvp);
1.10 cgd 649: }
1.12 mycroft 650: if ((cnp->cn_flags & LOCKLEAF) == 0)
1.26 fvdl 651: VOP_UNLOCK(dp, 0);
1.10 cgd 652: return (0);
653:
654: bad2:
1.31 wrstuden 655: if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN) &&
656: ((cnp->cn_flags & PDIRUNLOCK) == 0))
1.26 fvdl 657: VOP_UNLOCK(ndp->ni_dvp, 0);
1.10 cgd 658: vrele(ndp->ni_dvp);
659: bad:
1.32 wrstuden 660: if (dpunlocked)
661: vrele(dp);
662: else
663: vput(dp);
1.10 cgd 664: ndp->ni_vp = NULL;
1.12 mycroft 665: return (error);
666: }
667:
668: /*
669: * Reacquire a path name component.
670: */
671: int
672: relookup(dvp, vpp, cnp)
673: struct vnode *dvp, **vpp;
674: struct componentname *cnp;
675: {
1.26 fvdl 676: struct vnode *dp = 0; /* the directory we are searching */
1.12 mycroft 677: int wantparent; /* 1 => wantparent or lockparent flag */
678: int rdonly; /* lookup read-only flag bit */
679: int error = 0;
1.52 yamt 680: #ifdef DEBUG
1.54 hannken 681: u_long newhash; /* DEBUG: check name hash */
1.41 soren 682: const char *cp; /* DEBUG: check name ptr/len */
1.52 yamt 683: #endif /* DEBUG */
1.12 mycroft 684:
685: /*
686: * Setup: break out flag bits into variables.
687: */
688: wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
689: rdonly = cnp->cn_flags & RDONLY;
690: cnp->cn_flags &= ~ISSYMLINK;
691: dp = dvp;
1.26 fvdl 692: vn_lock(dp, LK_EXCLUSIVE | LK_RETRY);
1.12 mycroft 693:
694: /* dirloop: */
695: /*
696: * Search a new directory.
697: *
698: * The cn_hash value is for use by vfs_cache.
699: * The last component of the filename is left accessible via
700: * cnp->cn_nameptr for callers that need the name. Callers needing
701: * the name set the SAVENAME flag. When done, they assume
702: * responsibility for freeing the pathname buffer.
703: */
1.52 yamt 704: #ifdef DEBUG
1.39 lukem 705: cp = NULL;
706: newhash = namei_hash(cnp->cn_nameptr, &cp);
1.12 mycroft 707: if (newhash != cnp->cn_hash)
708: panic("relookup: bad hash");
709: if (cnp->cn_namelen != cp - cnp->cn_nameptr)
710: panic ("relookup: bad len");
1.53 yamt 711: while (*cp == '/')
712: cp++;
1.12 mycroft 713: if (*cp != 0)
714: panic("relookup: not last component");
1.52 yamt 715: #endif /* DEBUG */
716: #ifdef NAMEI_DIAGNOSTIC
1.19 christos 717: printf("{%s}: ", cnp->cn_nameptr);
1.52 yamt 718: #endif /* NAMEI_DIAGNOSTIC */
1.12 mycroft 719:
720: /*
721: * Check for degenerate name (e.g. / or "")
722: * which is a way of talking about a directory,
723: * e.g. like "/." or ".".
724: */
1.23 mycroft 725: if (cnp->cn_nameptr[0] == '\0')
726: panic("relookup: null name");
1.12 mycroft 727:
728: if (cnp->cn_flags & ISDOTDOT)
729: panic ("relookup: lookup on dot-dot");
730:
731: /*
732: * We now have a segment name to search for, and a directory to search.
733: */
1.16 christos 734: if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
1.12 mycroft 735: #ifdef DIAGNOSTIC
736: if (*vpp != NULL)
1.43 christos 737: panic("leaf `%s' should be empty", cnp->cn_nameptr);
1.12 mycroft 738: #endif
739: if (error != EJUSTRETURN)
740: goto bad;
741: /*
742: * If creating and at end of pathname, then can consider
743: * allowing file to be created.
744: */
1.26 fvdl 745: if (rdonly) {
1.12 mycroft 746: error = EROFS;
747: goto bad;
748: }
749: /* ASSERT(dvp == ndp->ni_startdir) */
750: if (cnp->cn_flags & SAVESTART)
751: VREF(dvp);
752: /*
753: * We return with ni_vp NULL to indicate that the entry
754: * doesn't currently exist, leaving a pointer to the
755: * (possibly locked) directory inode in ndp->ni_dvp.
756: */
757: return (0);
758: }
759: dp = *vpp;
760:
761: #ifdef DIAGNOSTIC
762: /*
763: * Check for symbolic link
764: */
765: if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW))
766: panic ("relookup: symlink found.\n");
767: #endif
768:
769: /*
770: * Check for read-only file systems.
771: */
1.26 fvdl 772: if (rdonly &&
773: (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
774: error = EROFS;
775: goto bad2;
1.12 mycroft 776: }
777: /* ASSERT(dvp == ndp->ni_startdir) */
778: if (cnp->cn_flags & SAVESTART)
779: VREF(dvp);
780: if (!wantparent)
781: vrele(dvp);
782: if ((cnp->cn_flags & LOCKLEAF) == 0)
1.26 fvdl 783: VOP_UNLOCK(dp, 0);
1.12 mycroft 784: return (0);
785:
786: bad2:
787: if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
1.26 fvdl 788: VOP_UNLOCK(dvp, 0);
1.12 mycroft 789: vrele(dvp);
790: bad:
791: vput(dp);
792: *vpp = NULL;
1.10 cgd 793: return (error);
794: }
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