/*
- * Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1999-2012 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
*
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
*
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1989, 1993
*
* hfs_lookup.c -- code to handle directory traversal on HFS/HFS+ volume
*/
-#define LEGACY_FORK_NAMES 0
#include <sys/param.h>
-#include <sys/buf.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/vnode.h>
-#include <sys/namei.h>
#include <sys/malloc.h>
-#include <sys/paths.h>
+#include <sys/kdebug.h>
+#include <sys/kauth.h>
+#include <sys/namei.h>
+#include <sys/user.h>
#include "hfs.h"
#include "hfs_catalog.h"
#include "hfs_cnode.h"
-static int forkcomponent(struct componentname *cnp, int *rsrcfork);
-
-#define _PATH_DATAFORKSPEC "/..namedfork/data"
-
-#ifdef LEGACY_FORK_NAMES
-#define LEGACY_RSRCFORKSPEC "/rsrc"
-#endif
-
/*
* FROM FREEBSD 3.1
* Convert a component of a pathname into a pointer to a locked cnode.
* creating, renaming, or deleting a directory entry may be calculated.
* Notice that these are the only operations that can affect the directory of the target.
*
- * If flag has LOCKPARENT or'ed into it and the target of the pathname
- * exists, lookup returns both the target and its parent directory locked.
- * When creating or renaming and LOCKPARENT is specified, the target may
- * not be ".". When deleting and LOCKPARENT is specified, the target may
- * be "."., but the caller must check to ensure it does an vrele and vput
- * instead of two vputs.
- *
* LOCKPARENT and WANTPARENT actually refer to the parent of the last item,
* so if ISLASTCN is not set, they should be ignored. Also they are mutually exclusive, or
* WANTPARENT really implies DONTLOCKPARENT. Either of them set means that the calling
* Keeping the parent locked as long as possible protects from other processes
* looking up the same item, so it has to be locked until the cnode is totally finished
*
- * This routine is actually used as VOP_CACHEDLOOKUP method, and the
- * filesystem employs the generic hfs_cache_lookup() as VOP_LOOKUP
- * method.
- *
* hfs_cache_lookup() performs the following for us:
* check that it is a directory
* check accessibility of directory
* drop it
* else
* return name.
- * return VOP_CACHEDLOOKUP()
+ * return hfs_lookup()
*
* Overall outline of hfs_lookup:
*
* nor deleting, add name to cache
*/
+
/*
- * Lookup *nm in directory *pvp, return it in *a_vpp.
- * **a_vpp is held on exit.
+ * Lookup *cnp in directory *dvp, return it in *vpp.
+ * **vpp is held on exit.
* We create a cnode for the file, but we do NOT open the file here.
#% lookup dvp L ? ?
* When should we lock parent_hp in here ??
*/
-
-__private_extern__
-int
-hfs_lookup(ap)
- struct vop_cachedlookup_args /* {
- struct vnode *a_dvp;
- struct vnode **a_vpp;
- struct componentname *a_cnp;
- } */ *ap;
+static int
+hfs_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp, int *cnode_locked)
{
- struct vnode *dvp; /* vnode for directory being searched */
struct cnode *dcp; /* cnode for directory being searched */
struct vnode *tvp; /* target vnode */
struct hfsmount *hfsmp;
- struct componentname *cnp;
- struct ucred *cred;
- struct proc *p;
- int wantrsrc = 0;
- int forknamelen = 0;
int flags;
- int wantparent;
int nameiop;
int retval = 0;
int isDot;
- struct cat_desc desc = {0};
+ struct cat_desc desc;
struct cat_desc cndesc;
struct cat_attr attr;
struct cat_fork fork;
- struct vnode **vpp;
+ int lockflags;
+ int newvnode_flags;
- vpp = ap->a_vpp;
- cnp = ap->a_cnp;
- dvp = ap->a_dvp;
- dcp = VTOC(dvp);
+ retry:
+ newvnode_flags = 0;
+ dcp = NULL;
hfsmp = VTOHFS(dvp);
*vpp = NULL;
+ *cnode_locked = 0;
isDot = FALSE;
tvp = NULL;
nameiop = cnp->cn_nameiop;
- cred = cnp->cn_cred;
- p = cnp->cn_proc;
flags = cnp->cn_flags;
- wantparent = flags & (LOCKPARENT|WANTPARENT);
+ bzero(&desc, sizeof(desc));
/*
* First check to see if it is a . or .., else look it up.
*/
if (flags & ISDOTDOT) { /* Wanting the parent */
+ cnp->cn_flags &= ~MAKEENTRY;
goto found; /* .. is always defined */
} else if ((cnp->cn_nameptr[0] == '.') && (cnp->cn_namelen == 1)) {
isDot = TRUE;
+ cnp->cn_flags &= ~MAKEENTRY;
goto found; /* We always know who we are */
} else {
- /* Check fork suffix to see if we want the resource fork */
- forknamelen = forkcomponent(cnp, &wantrsrc);
+ if (hfs_lock(VTOC(dvp), HFS_EXCLUSIVE_LOCK) != 0) {
+ retval = ENOENT; /* The parent no longer exists ? */
+ goto exit;
+ }
+ dcp = VTOC(dvp);
+
+ if (dcp->c_flag & C_DIR_MODIFICATION) {
+ // XXXdbg - if we could msleep on a lck_rw_t then we would do that
+ // but since we can't we have to unlock, delay for a bit
+ // and then retry...
+ // msleep((caddr_t)&dcp->c_flag, &dcp->c_rwlock, PINOD, "hfs_vnop_lookup", 0);
+ hfs_unlock(dcp);
+ tsleep((caddr_t)dvp, PRIBIO, "hfs_lookup", 1);
+
+ goto retry;
+ }
/* No need to go to catalog if there are no children */
- if (dcp->c_entries == 0)
+ if (dcp->c_entries == 0) {
goto notfound;
+ }
bzero(&cndesc, sizeof(cndesc));
- cndesc.cd_nameptr = cnp->cn_nameptr;
+ cndesc.cd_nameptr = (const u_int8_t *)cnp->cn_nameptr;
cndesc.cd_namelen = cnp->cn_namelen;
- cndesc.cd_parentcnid = dcp->c_cnid;
+ cndesc.cd_parentcnid = dcp->c_fileid;
cndesc.cd_hint = dcp->c_childhint;
- /* Lock catalog b-tree */
- retval = hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_SHARED, p);
- if (retval)
- goto exit;
- retval = cat_lookup(hfsmp, &cndesc, wantrsrc, &desc, &attr, &fork);
+ lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
+
+ retval = cat_lookup(hfsmp, &cndesc, 0, &desc, &attr, &fork, NULL);
- if (retval == 0 && S_ISREG(attr.ca_mode) && attr.ca_blocks < fork.cf_blocks)
- panic("hfs_lookup: bad ca_blocks (too small)");
-
- /* Unlock catalog b-tree */
- (void) hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_RELEASE, p);
+ hfs_systemfile_unlock(hfsmp, lockflags);
+
if (retval == 0) {
dcp->c_childhint = desc.cd_hint;
+ /*
+ * Note: We must drop the parent lock here before calling
+ * hfs_getnewvnode (which takes the child lock).
+ */
+ hfs_unlock(dcp);
+ dcp = NULL;
+
+ /* Verify that the item just looked up isn't one of the hidden directories. */
+ if (desc.cd_cnid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid ||
+ desc.cd_cnid == hfsmp->hfs_private_desc[DIR_HARDLINKS].cd_cnid) {
+ retval = ENOENT;
+ goto exit;
+ }
+
goto found;
}
notfound:
+ /*
+ * ENAMETOOLONG supersedes other errors
+ *
+ * For a CREATE or RENAME operation on the last component
+ * the ENAMETOOLONG will be handled in the next VNOP.
+ */
+ if ((retval != ENAMETOOLONG) &&
+ (cnp->cn_namelen > kHFSPlusMaxFileNameChars) &&
+ (((flags & ISLASTCN) == 0) || ((nameiop != CREATE) && (nameiop != RENAME)))) {
+ retval = ENAMETOOLONG;
+ } else if (retval == 0) {
+ retval = ENOENT;
+ }
+ if (retval != ENOENT)
+ goto exit;
/*
* This is a non-existing entry
*
*/
if ((nameiop == CREATE || nameiop == RENAME ||
(nameiop == DELETE &&
- (ap->a_cnp->cn_flags & DOWHITEOUT) &&
- (ap->a_cnp->cn_flags & ISWHITEOUT))) &&
- (flags & ISLASTCN)) {
- /*
- * Access for write is interpreted as allowing
- * creation of files in the directory.
- */
- retval = VOP_ACCESS(dvp, VWRITE, cred, cnp->cn_proc);
- if (retval) {
- goto exit;
- }
-
- cnp->cn_flags |= SAVENAME;
- if (!(flags & LOCKPARENT))
- VOP_UNLOCK(dvp, 0, p);
+ (cnp->cn_flags & DOWHITEOUT) &&
+ (cnp->cn_flags & ISWHITEOUT))) &&
+ (flags & ISLASTCN) &&
+ !(ISSET(dcp->c_flag, C_DELETED | C_NOEXISTS))) {
retval = EJUSTRETURN;
goto exit;
}
-
/*
- * Insert name into cache (as non-existent) if appropriate.
- *
- * Disable negative caching since HFS is case-insensitive.
+ * Insert name into the name cache (as non-existent).
*/
-#if 0
- if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
- cache_enter(dvp, *vpp, cnp);
-#endif
- retval = ENOENT;
+ if ((hfsmp->hfs_flags & HFS_STANDARD) == 0 &&
+ (cnp->cn_flags & MAKEENTRY) &&
+ (nameiop != CREATE)) {
+ cache_enter(dvp, NULL, cnp);
+ dcp->c_flag |= C_NEG_ENTRIES;
+ }
goto exit;
}
found:
- /*
- * Process any fork specifiers
- */
- if (forknamelen && S_ISREG(attr.ca_mode)) {
- /* fork names are only for lookups */
- if ((nameiop != LOOKUP) && (nameiop != CREATE)) {
- retval = EPERM;
- goto exit;
- }
- cnp->cn_consume = forknamelen;
- flags |= ISLASTCN;
- } else {
- wantrsrc = 0;
- forknamelen = 0;
- }
-
- /*
- * If deleting, and at end of pathname, return
- * parameters which can be used to remove file.
- */
- if (nameiop == DELETE && (flags & ISLASTCN)) {
- /*
- * Write access to directory required to delete files.
- */
- if ((retval = VOP_ACCESS(dvp, VWRITE, cred, cnp->cn_proc)))
- goto exit;
-
- if (isDot) { /* Want to return ourselves */
- VREF(dvp);
- *vpp = dvp;
- goto exit;
- } else if (flags & ISDOTDOT) {
- retval = hfs_getcnode(hfsmp, dcp->c_parentcnid,
- NULL, 0, NULL, NULL, &tvp);
- if (retval)
+ if (flags & ISLASTCN) {
+ switch(nameiop) {
+ case DELETE:
+ cnp->cn_flags &= ~MAKEENTRY;
+ break;
+
+ case RENAME:
+ cnp->cn_flags &= ~MAKEENTRY;
+ if (isDot) {
+ retval = EISDIR;
goto exit;
- } else {
- retval = hfs_getcnode(hfsmp, attr.ca_fileid,
- &desc, wantrsrc, &attr, &fork, &tvp);
- if (retval)
- goto exit;
- }
-
- /*
- * If directory is "sticky", then user must own
- * the directory, or the file in it, else she
- * may not delete it (unless she's root). This
- * implements append-only directories.
- */
- if ((dcp->c_mode & S_ISTXT) &&
- (cred->cr_uid != 0) &&
- (cred->cr_uid != dcp->c_uid) &&
- (tvp->v_type != VLNK) &&
- (hfs_owner_rights(hfsmp, VTOC(tvp)->c_uid, cred, p, false))) {
- vput(tvp);
- retval = EPERM;
- goto exit;
+ }
+ break;
}
+ }
- /*
- * If this is a link node then we need to save the name
- * (of the link) so we can delete it from the catalog b-tree.
- * In this case, hfs_remove will then free the component name.
- *
- * DJB - IS THIS STILL NEEDED????
- */
- if (tvp && (VTOC(tvp)->c_flag & C_HARDLINK))
- cnp->cn_flags |= SAVENAME;
-
- if (!(flags & LOCKPARENT))
- VOP_UNLOCK(dvp, 0, p);
- *vpp = tvp;
- goto exit;
- }
-
- /*
- * If renaming, return the cnode and save the current name.
- */
- if (nameiop == RENAME && wantparent && (flags & ISLASTCN)) {
- if ((retval = VOP_ACCESS(dvp, VWRITE, cred, cnp->cn_proc)) != 0)
+ if (isDot) {
+ if ((retval = vnode_get(dvp)))
goto exit;
+ *vpp = dvp;
+ } else if (flags & ISDOTDOT) {
/*
- * Careful about locking second cnode.
+ * Directory hard links can have multiple parents so
+ * find the appropriate parent for the current thread.
*/
- if (isDot) {
- retval = EISDIR;
+ if ((retval = hfs_vget(hfsmp, hfs_currentparent(VTOC(dvp)), &tvp, 0, 0))) {
goto exit;
- } else if (flags & ISDOTDOT) {
- retval = hfs_getcnode(hfsmp, dcp->c_parentcnid,
- NULL, 0, NULL, NULL, &tvp);
- if (retval)
- goto exit;
- } else {
- retval = hfs_getcnode(hfsmp, attr.ca_fileid,
- &desc, wantrsrc, &attr, &fork, &tvp);
- if (retval)
- goto exit;
}
- cnp->cn_flags |= SAVENAME;
- if (!(flags & LOCKPARENT))
- VOP_UNLOCK(dvp, 0, p);
+ *cnode_locked = 1;
*vpp = tvp;
- goto exit;
- }
-
- /*
- * We must get the target cnode before unlocking
- * the directory to insure that the cnode will not be removed
- * before we get it. We prevent deadlock by always fetching
- * cnodes from the root, moving down the directory tree. Thus
- * when following backward pointers ".." we must unlock the
- * parent directory before getting the requested directory.
- * There is a potential race condition here if both the current
- * and parent directories are removed before the VFS_VGET for the
- * cnode associated with ".." returns. We hope that this occurs
- * infrequently since we cannot avoid this race condition without
- * implementing a sophisticated deadlock detection algorithm.
- */
- if (flags & ISDOTDOT) {
- VOP_UNLOCK(dvp, 0, p); /* race to get the cnode */
- retval = hfs_getcnode(hfsmp, dcp->c_parentcnid,
- NULL, 0, NULL, NULL, &tvp);
- if (retval) {
- vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
- goto exit;
- }
- if ((flags & LOCKPARENT) && (flags & ISLASTCN) && (dvp != tvp) &&
- (retval = vn_lock(dvp, LK_EXCLUSIVE, p))) {
- vput(tvp);
- goto exit;
- }
- *vpp = tvp;
- } else if (isDot) {
- VREF(dvp); /* we want ourself, ie "." */
- *vpp = dvp;
} else {
int type = (attr.ca_mode & S_IFMT);
- if (!(flags & ISLASTCN) && type != S_IFDIR && type != S_IFLNK) {
+ if (!(flags & ISLASTCN) && (type != S_IFDIR) && (type != S_IFLNK)) {
retval = ENOTDIR;
goto exit;
}
+ /* Don't cache directory hardlink names. */
+ if (attr.ca_recflags & kHFSHasLinkChainMask) {
+ cnp->cn_flags &= ~MAKEENTRY;
+ }
+ /* Names with composed chars are not cached. */
+ if (cnp->cn_namelen != desc.cd_namelen)
+ cnp->cn_flags &= ~MAKEENTRY;
- retval = hfs_getcnode(hfsmp, attr.ca_fileid,
- &desc, wantrsrc, &attr, &fork, &tvp);
- if (retval)
+ retval = hfs_getnewvnode(hfsmp, dvp, cnp, &desc, 0, &attr, &fork, &tvp, &newvnode_flags);
+
+ if (retval) {
+ /*
+ * If this was a create/rename operation lookup, then by this point
+ * we expected to see the item returned from hfs_getnewvnode above.
+ * In the create case, it would probably eventually bubble out an EEXIST
+ * because the item existed when we were trying to create it. In the
+ * rename case, it would let us know that we need to go ahead and
+ * delete it as part of the rename. However, if we hit the condition below
+ * then it means that we found the element during cat_lookup above, but
+ * it is now no longer there. We simply behave as though we never found
+ * the element at all and return EJUSTRETURN.
+ */
+ if ((retval == ENOENT) &&
+ ((cnp->cn_nameiop == CREATE) || (cnp->cn_nameiop == RENAME)) &&
+ (flags & ISLASTCN)) {
+ retval = EJUSTRETURN;
+ }
+
+ /*
+ * If this was a straight lookup operation, we may need to redrive the entire
+ * lookup starting from cat_lookup if the element was deleted as the result of
+ * a rename operation. Since rename is supposed to guarantee atomicity, then
+ * lookups cannot fail because the underlying element is deleted as a result of
+ * the rename call -- either they returned the looked up element prior to rename
+ * or return the newer element. If we are in this region, then all we can do is add
+ * workarounds to guarantee the latter case. The element has already been deleted, so
+ * we just re-try the lookup to ensure the caller gets the most recent element.
+ */
+ if ((retval == ENOENT) && (cnp->cn_nameiop == LOOKUP) &&
+ (newvnode_flags & (GNV_CHASH_RENAMED | GNV_CAT_DELETED))) {
+ if (dcp) {
+ hfs_unlock (dcp);
+ }
+ /* get rid of any name buffers that may have lingered from the cat_lookup call */
+ cat_releasedesc (&desc);
+ goto retry;
+ }
+
+ /* Also, re-drive the lookup if the item we looked up was a hardlink, and the number
+ * or name of hardlinks has changed in the interim between the cat_lookup above, and
+ * our call to hfs_getnewvnode. hfs_getnewvnode will validate the cattr we passed it
+ * against what is actually in the catalog after the cnode is created. If there were
+ * any issues, it will bubble out ERECYCLE, which we need to swallow and use as the
+ * key to redrive as well. We need to special case this below because in this case,
+ * it needs to occur regardless of the type of lookup we're doing here.
+ */
+ if ((retval == ERECYCLE) && (newvnode_flags & GNV_CAT_ATTRCHANGED)) {
+ if (dcp) {
+ hfs_unlock (dcp);
+ }
+ /* get rid of any name buffers that may have lingered from the cat_lookup call */
+ cat_releasedesc (&desc);
+ retval = 0;
+ goto retry;
+ }
+
+ /* skip to the error-handling code if we can't retry */
goto exit;
+ }
- if (!(flags & LOCKPARENT) || !(flags & ISLASTCN))
- VOP_UNLOCK(dvp, 0, p);
+ /*
+ * Save the origin info for file and directory hardlinks. Directory hardlinks
+ * need the origin for '..' lookups, and file hardlinks need it to ensure that
+ * competing lookups do not cause us to vend different hardlinks than the ones requested.
+ * We want to restrict saving the cache entries to LOOKUP namei operations, since
+ * we're really doing this to protect getattr.
+ */
+ if ((nameiop == LOOKUP) && (VTOC(tvp)->c_flag & C_HARDLINK)) {
+ hfs_savelinkorigin(VTOC(tvp), VTOC(dvp)->c_fileid);
+ }
+ *cnode_locked = 1;
*vpp = tvp;
}
-
- /*
- * Insert name in cache if appropriate.
- * - "." and ".." are not cached.
- * - Resource fork names are not cached.
- * - Names with composed chars are not cached.
- */
- if ((cnp->cn_flags & MAKEENTRY)
- && !isDot
- && !(flags & ISDOTDOT)
- && !wantrsrc
- && (cnp->cn_namelen == VTOC(*vpp)->c_desc.cd_namelen)) {
- cache_enter(dvp, *vpp, cnp);
- }
-
exit:
+ if (dcp) {
+ hfs_unlock(dcp);
+ }
cat_releasedesc(&desc);
return (retval);
}
/*
- * Based on vn_cache_lookup (which is vfs_cache_lookup in FreeBSD 3.1)
- *
* Name caching works as follows:
*
* Names found by directory scans are retained in a cache
*
*/
-__private_extern__
+#define S_IXALL 0000111
+
int
-hfs_cache_lookup(ap)
- struct vop_lookup_args /* {
- struct vnode *a_dvp;
- struct vnode **a_vpp;
- struct componentname *a_cnp;
- } */ *ap;
+hfs_vnop_lookup(struct vnop_lookup_args *ap)
{
- struct vnode *dvp;
+ struct vnode *dvp = ap->a_dvp;
struct vnode *vp;
struct cnode *cp;
- int lockparent;
+ struct cnode *dcp;
+ struct hfsmount *hfsmp;
int error;
struct vnode **vpp = ap->a_vpp;
struct componentname *cnp = ap->a_cnp;
- struct ucred *cred = cnp->cn_cred;
int flags = cnp->cn_flags;
- struct proc *p = cnp->cn_proc;
- u_long vpid; /* capability number of vnode */
+ int cnode_locked;
*vpp = NULL;
- dvp = ap->a_dvp;
- lockparent = flags & LOCKPARENT;
-
- /*
- * Check accessiblity of directory.
- */
- if (dvp->v_type != VDIR)
- return (ENOTDIR);
- if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
- (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
- return (EROFS);
- if ((error = VOP_ACCESS(dvp, VEXEC, cred, cnp->cn_proc)))
- return (error);
+ dcp = VTOC(dvp);
+
+ hfsmp = VTOHFS(dvp);
/*
* Lookup an entry in the cache
- * If the lookup succeeds, the vnode is returned in *vpp, and a status of -1 is
- * returned. If the lookup determines that the name does not exist
- * (negative cacheing), a status of ENOENT is returned. If the lookup
- * fails, a status of zero is returned.
+ *
+ * If the lookup succeeds, the vnode is returned in *vpp,
+ * and a status of -1 is returned.
+ *
+ * If the lookup determines that the name does not exist
+ * (negative cacheing), a status of ENOENT is returned.
+ *
+ * If the lookup fails, a status of zero is returned.
*/
error = cache_lookup(dvp, vpp, cnp);
- if (error == 0) { /* Unsuccessfull */
- error = hfs_lookup(ap);
- return (error);
+ if (error != -1) {
+ if ((error == ENOENT) && (cnp->cn_nameiop != CREATE))
+ goto exit; /* found a negative cache entry */
+ goto lookup; /* did not find it in the cache */
+ }
+ /*
+ * We have a name that matched
+ * cache_lookup returns the vp with an iocount reference already taken
+ */
+ error = 0;
+ vp = *vpp;
+ cp = VTOC(vp);
+
+ /* We aren't allowed to vend out vp's via lookup to the hidden directory */
+ if (cp->c_cnid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid ||
+ cp->c_cnid == hfsmp->hfs_private_desc[DIR_HARDLINKS].cd_cnid) {
+ /* Drop the iocount from cache_lookup */
+ vnode_put (vp);
+ error = ENOENT;
+ goto exit;
}
- if (error == ENOENT)
- return (error);
- /* We have a name that matched */
- vp = *vpp;
- vpid = vp->v_id;
-
/*
* If this is a hard-link vnode then we need to update
* the name (of the link), the parent ID, the cnid, the
* text encoding and the catalog hint. This enables
* getattrlist calls to return the correct link info.
*/
- cp = VTOC(vp);
- if ((flags & ISLASTCN) && (cp->c_flag & C_HARDLINK) &&
- ((cp->c_parentcnid != VTOC(ap->a_dvp)->c_cnid) ||
- (bcmp(cnp->cn_nameptr, cp->c_desc.cd_nameptr, cp->c_desc.cd_namelen) != 0))) {
-
- struct cat_desc desc;
- /*
- * Get an updated descriptor
- */
- bzero(&desc, sizeof(desc));
- desc.cd_nameptr = cnp->cn_nameptr;
- desc.cd_namelen = cnp->cn_namelen;
- desc.cd_parentcnid = VTOC(ap->a_dvp)->c_cnid;
- desc.cd_hint = VTOC(ap->a_dvp)->c_childhint;
- if (cat_lookup(VTOHFS(vp), &desc, 0, &desc, NULL, NULL) == 0)
- replace_desc(cp, &desc);
- }
+ if ((flags & ISLASTCN) && (cp->c_flag & C_HARDLINK)) {
+ int stale_link = 0;
- if (dvp == vp) { /* lookup on "." */
- VREF(vp);
- error = 0;
- } else if (flags & ISDOTDOT) {
- /*
- * Carefull on the locking policy,
- * remember we always lock from parent to child, so have
- * to release lock on child before trying to lock parent
- * then regain lock if needed
- */
- VOP_UNLOCK(dvp, 0, p);
- error = vget(vp, LK_EXCLUSIVE, p);
- if (!error && lockparent && (flags & ISLASTCN))
- error = vn_lock(dvp, LK_EXCLUSIVE, p);
- } else {
- if ((flags & ISLASTCN) == 0 && vp->v_type == VREG) {
- int wantrsrc = 0;
+ hfs_lock(cp, HFS_FORCE_LOCK);
+ if ((cp->c_parentcnid != dcp->c_cnid) ||
+ (bcmp(cnp->cn_nameptr, cp->c_desc.cd_nameptr, cp->c_desc.cd_namelen) != 0)) {
+ struct cat_desc desc;
+ struct cat_attr lookup_attr;
+ int lockflags;
+ /*
+ * Get an updated descriptor
+ */
+ desc.cd_nameptr = (const u_int8_t *)cnp->cn_nameptr;
+ desc.cd_namelen = cnp->cn_namelen;
+ desc.cd_parentcnid = dcp->c_fileid;
+ desc.cd_hint = dcp->c_childhint;
+ desc.cd_encoding = 0;
+ desc.cd_cnid = 0;
+ desc.cd_flags = S_ISDIR(cp->c_mode) ? CD_ISDIR : 0;
- cnp->cn_consume = forkcomponent(cnp, &wantrsrc);
+ /*
+ * Because lookups call replace_desc to put a new descriptor in
+ * the cnode we are modifying it is possible that this cnode's
+ * descriptor is out of date for the parent ID / name that
+ * we are trying to look up. (It may point to a different hardlink).
+ *
+ * We need to be cautious that when re-supplying the
+ * descriptor below that the results of the catalog lookup
+ * still point to the same raw inode for the hardlink. This would
+ * not be the case if we found something in the cache above but
+ * the vnode it returned no longer has a valid hardlink for the
+ * parent ID/filename combo we are requesting. (This is because
+ * hfs_unlink does not directly trigger namecache removal).
+ *
+ * As a result, before vending out the vnode (and replacing
+ * its descriptor) verify that the fileID is the same by comparing
+ * the in-cnode attributes vs. the one returned from the lookup call
+ * below. If they do not match, treat this lookup as if we never hit
+ * in the cache at all.
+ */
+
+ lockflags = hfs_systemfile_lock(VTOHFS(dvp), SFL_CATALOG, HFS_SHARED_LOCK);
+
+ error = cat_lookup(VTOHFS(vp), &desc, 0, &desc, &lookup_attr, NULL, NULL);
- /* Fork names are only for lookups */
- if (cnp->cn_consume &&
- (cnp->cn_nameiop != LOOKUP && cnp->cn_nameiop != CREATE))
- return (EPERM);
+ hfs_systemfile_unlock(VTOHFS(dvp), lockflags);
+
/*
- * We only store data forks in the name cache.
- */
- if (wantrsrc)
- return (hfs_lookup(ap));
+ * Note that cat_lookup may fail to find something with the name provided in the
+ * stack-based descriptor above. In that case, an ENOENT is a legitimate errno
+ * to be placed in error, which will get returned in the fastpath below.
+ */
+ if (error == 0) {
+ if (lookup_attr.ca_fileid == cp->c_attr.ca_fileid) {
+ /* It still points to the right raw inode. Replacing the descriptor is fine */
+ replace_desc (cp, &desc);
+
+ /*
+ * Save the origin info for file and directory hardlinks. Directory hardlinks
+ * need the origin for '..' lookups, and file hardlinks need it to ensure that
+ * competing lookups do not cause us to vend different hardlinks than the ones requested.
+ * We want to restrict saving the cache entries to LOOKUP namei operations, since
+ * we're really doing this to protect getattr.
+ */
+ if (cnp->cn_nameiop == LOOKUP) {
+ hfs_savelinkorigin(cp, dcp->c_fileid);
+ }
+ }
+ else {
+ /* If the fileID does not match then do NOT replace the descriptor! */
+ stale_link = 1;
+ }
+ }
}
- error = vget(vp, LK_EXCLUSIVE, p);
- if (!lockparent || error || !(flags & ISLASTCN))
- VOP_UNLOCK(dvp, 0, p);
- }
+ hfs_unlock (cp);
+
+ if (stale_link) {
+ /*
+ * If we had a stale_link, then we need to pretend as though
+ * we never found this vnode and force a lookup through the
+ * traditional path. Drop the iocount acquired through
+ * cache_lookup above and force a cat lookup / getnewvnode
+ */
+ vnode_put(vp);
+ goto lookup;
+ }
+
+ if (error) {
+ /*
+ * If the cat_lookup failed then the caller will not expect
+ * a vnode with an iocount on it.
+ */
+ vnode_put(vp);
+ }
+
+ }
+ goto exit;
+
+lookup:
/*
- * Check that the capability number did not change
- * while we were waiting for the lock.
+ * The vnode was not in the name cache or it was stale.
+ *
+ * So we need to do a real lookup.
*/
- if (!error) {
- if (vpid == vp->v_id)
- return (0);
- /*
- * The above is the NORMAL exit, after this point is an error
- * condition.
- */
- vput(vp);
- if (lockparent && (dvp != vp) && (flags & ISLASTCN))
- VOP_UNLOCK(dvp, 0, p);
- }
-
- if ((error = vn_lock(dvp, LK_EXCLUSIVE, p)))
- return (error);
-
- return (hfs_lookup(ap));
-}
-
+ cnode_locked = 0;
-/*
- * forkcomponent - look for a fork suffix in the component name
- *
- */
-static int
-forkcomponent(struct componentname *cnp, int *rsrcfork)
-{
- char *suffix = cnp->cn_nameptr + cnp->cn_namelen;
- int consume = 0;
+ error = hfs_lookup(dvp, vpp, cnp, &cnode_locked);
+
+ if (cnode_locked)
+ hfs_unlock(VTOC(*vpp));
+exit:
+ {
+ uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread());
- *rsrcfork = 0;
- if (*suffix == '\0')
- return (0);
/*
- * There are only 3 valid fork suffixes:
- * "/..namedfork/rsrc"
- * "/..namedfork/data"
- * "/rsrc" (legacy)
+ * check to see if we issued any I/O while completing this lookup and
+ * this thread/task is throttleable... if so, throttle now
+ *
+ * this allows us to throttle in between multiple meta data reads that
+ * might result due to looking up a long pathname (since we'll have to
+ * re-enter hfs_vnop_lookup for each component of the pathnam not in
+ * the VFS cache), instead of waiting until the entire path lookup has
+ * completed and throttling at the systemcall return
*/
- if (bcmp(suffix, _PATH_RSRCFORKSPEC, sizeof(_PATH_RSRCFORKSPEC)) == 0) {
- consume = sizeof(_PATH_RSRCFORKSPEC) - 1;
- *rsrcfork = 1;
- } else if (bcmp(suffix, _PATH_DATAFORKSPEC, sizeof(_PATH_DATAFORKSPEC)) == 0) {
- consume = sizeof(_PATH_DATAFORKSPEC) - 1;
+ if (__improbable(ut->uu_lowpri_window)) {
+ throttle_lowpri_io(TRUE);
}
-
-#ifdef LEGACY_FORK_NAMES
- else if (bcmp(suffix, LEGACY_RSRCFORKSPEC, sizeof(LEGACY_RSRCFORKSPEC)) == 0) {
- consume = sizeof(LEGACY_RSRCFORKSPEC) - 1;
- *rsrcfork = 1;
}
-#endif
- return (consume);
+
+ return (error);
}
+
projects / apple / xnu.git / blobdiff