/*
- * Copyright (c) 1999-2007 Apple Inc. All rights reserved.
+ * Copyright (c) 1999-2012 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
#include <sys/kdebug.h>
#include <sys/kauth.h>
#include <sys/namei.h>
+#include <sys/user.h>
#include "hfs.h"
#include "hfs_catalog.h"
* When should we lock parent_hp in here ??
*/
static int
-hfs_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp, int *cnode_locked)
+hfs_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp, int *cnode_locked, int force_casesensitive_lookup)
{
struct cnode *dcp; /* cnode for directory being searched */
struct vnode *tvp; /* target vnode */
struct cat_attr attr;
struct cat_fork fork;
int lockflags;
+ int newvnode_flags;
retry:
+ newvnode_flags = 0;
dcp = NULL;
hfsmp = VTOHFS(dvp);
*vpp = NULL;
cnp->cn_flags &= ~MAKEENTRY;
goto found; /* We always know who we are */
} else {
- if (hfs_lock(VTOC(dvp), HFS_EXCLUSIVE_LOCK) != 0) {
+ if (hfs_lock(VTOC(dvp), HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT) != 0) {
retval = ENOENT; /* The parent no longer exists ? */
goto exit;
}
goto retry;
}
- /* No need to go to catalog if there are no children */
- if (dcp->c_entries == 0) {
- goto notfound;
- }
+
+ /*
+ * We shouldn't need to go to the catalog if there are no children.
+ * However, in the face of a minor disk corruption where the valence of
+ * the directory is off, we could infinite loop here if we return ENOENT
+ * even though there are actually items in the directory. (create will
+ * see the ENOENT, try to create something, which will return with
+ * EEXIST over and over again). As a result, always check the catalog.
+ */
bzero(&cndesc, sizeof(cndesc));
cndesc.cd_nameptr = (const u_int8_t *)cnp->cn_nameptr;
lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
- retval = cat_lookup(hfsmp, &cndesc, 0, &desc, &attr, &fork, NULL);
+ retval = cat_lookup(hfsmp, &cndesc, 0, force_casesensitive_lookup, &desc, &attr, &fork, NULL);
hfs_systemfile_unlock(hfsmp, lockflags);
* Note: We must drop the parent lock here before calling
* hfs_getnewvnode (which takes the child lock).
*/
- hfs_unlock(dcp);
- dcp = NULL;
+ 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
*
retval = ENAMETOOLONG;
} else if (retval == 0) {
retval = ENOENT;
+ } else if (retval == ERESERVEDNAME) {
+ /*
+ * We found the name in the catalog, but it is unavailable
+ * to us. The exact error to return to our caller depends
+ * on the operation, and whether we've already reached the
+ * last path component. In all cases, avoid a negative
+ * cache entry, since someone else may be able to access
+ * the name if their lookup is configured differently.
+ */
+
+ cnp->cn_flags &= ~MAKEENTRY;
+
+ if (((flags & ISLASTCN) == 0) || ((nameiop == LOOKUP) || (nameiop == DELETE))) {
+ /* A reserved name for a pure lookup is the same as the path not being present */
+ retval = ENOENT;
+ } else {
+ /* A reserved name with intent to create must be rejected as impossible */
+ retval = EEXIST;
+ }
}
if (retval != ENOENT)
goto exit;
* directory has not been removed, then can consider
* allowing file to be created.
*/
- if ((nameiop == CREATE || nameiop == RENAME ||
- (nameiop == DELETE &&
- (cnp->cn_flags & DOWHITEOUT) &&
- (cnp->cn_flags & ISWHITEOUT))) &&
+ if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & ISLASTCN) &&
!(ISSET(dcp->c_flag, C_DELETED | C_NOEXISTS))) {
retval = EJUSTRETURN;
* Directory hard links can have multiple parents so
* find the appropriate parent for the current thread.
*/
- if ((retval = hfs_vget(hfsmp, hfs_currentparent(VTOC(dvp)), &tvp, 0))) {
+ if ((retval = hfs_vget(hfsmp, hfs_currentparent(VTOC(dvp)), &tvp, 0, 0))) {
goto exit;
}
*cnode_locked = 1;
*vpp = tvp;
} else {
int type = (attr.ca_mode & S_IFMT);
-#if NAMEDRSRCFORK
- int rsrc_warn = 0;
- /*
- * Check if caller wants the resource fork but utilized
- * the legacy "file/rsrc" access path.
- *
- * This is deprecated behavior and support for it will not
- * be allowed beyond case insensitive HFS+ and even that
- * support will be removed in the next major OS release.
- */
- if ((type == S_IFREG) &&
- ((flags & ISLASTCN) == 0) &&
- (cnp->cn_nameptr[cnp->cn_namelen] == '/') &&
- (bcmp(&cnp->cn_nameptr[cnp->cn_namelen+1], "rsrc", 5) == 0) &&
- ((hfsmp->hfs_flags & (HFS_STANDARD | HFS_CASE_SENSITIVE)) == 0)) {
-
- cnp->cn_consume = 5;
- cnp->cn_flags |= CN_WANTSRSRCFORK | ISLASTCN | NOCACHE;
- cnp->cn_flags &= ~MAKEENTRY;
- flags |= ISLASTCN;
- rsrc_warn = 1;
- }
-#endif
if (!(flags & ISLASTCN) && (type != S_IFDIR) && (type != S_IFLNK)) {
retval = ENOTDIR;
goto exit;
if (cnp->cn_namelen != desc.cd_namelen)
cnp->cn_flags &= ~MAKEENTRY;
- retval = hfs_getnewvnode(hfsmp, dvp, cnp, &desc, 0, &attr, &fork, &tvp);
+ retval = hfs_getnewvnode(hfsmp, dvp, cnp, &desc, 0, &attr, &fork, &tvp, &newvnode_flags);
if (retval) {
/*
- * If this was a create operation lookup and another
- * process removed the object before we had a chance
- * to create the vnode, then just treat it as the not
- * found case above and return EJUSTRETURN.
- */
+ * 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) &&
- (flags & ISLASTCN)) {
+ ((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;
}
- /* Save the origin info of a directory link for future ".." requests. */
- if (S_ISDIR(attr.ca_mode) && (attr.ca_recflags & kHFSHasLinkChainMask)) {
+ /*
+ * 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;
-#if NAMEDRSRCFORK
- if (rsrc_warn) {
- if ((VTOC(tvp)->c_flag & C_WARNED_RSRC) == 0) {
- VTOC(tvp)->c_flag |= C_WARNED_RSRC;
- printf("%.200s: file access by '/rsrc' was deprecated in 10.4\n",
- cnp->cn_nameptr);
- }
- }
-#endif
}
exit:
if (dcp) {
#define S_IXALL 0000111
-__private_extern__
int
hfs_vnop_lookup(struct vnop_lookup_args *ap)
{
struct vnode *vp;
struct cnode *cp;
struct cnode *dcp;
+ struct hfsmount *hfsmp;
int error;
struct vnode **vpp = ap->a_vpp;
struct componentname *cnp = ap->a_cnp;
+ struct proc *p = vfs_context_proc(ap->a_context);
int flags = cnp->cn_flags;
+ int force_casesensitive_lookup = proc_is_forcing_hfs_case_sensitivity(p);
int cnode_locked;
*vpp = NULL;
dcp = VTOC(dvp);
+
+ hfsmp = VTOHFS(dvp);
/*
* Lookup an entry in the cache
*/
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 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)) {
- hfs_lock(cp, HFS_FORCE_LOCK);
+ /*
+ * Alternatively, if we are forcing a case-sensitive lookup
+ * on a case-insensitive volume, the namecache entry
+ * may have been for an incorrect case. Since we cannot
+ * determine case vs. normalization, redrive the catalog
+ * lookup based on any byte mismatch.
+ */
+ if (((flags & ISLASTCN) && (cp->c_flag & C_HARDLINK))
+ || (force_casesensitive_lookup && !(hfsmp->hfs_flags & HFS_CASE_SENSITIVE))) {
+ int stale_link = 0;
+
+ hfs_lock(cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_ALLOW_NOEXISTS);
if ((cp->c_parentcnid != dcp->c_cnid) ||
+ (cnp->cn_namelen != cp->c_desc.cd_namelen) ||
(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;
+ if (force_casesensitive_lookup && !(hfsmp->hfs_flags & HFS_CASE_SENSITIVE)) {
+ /*
+ * Since the name in the cnode doesn't match our lookup
+ * string exactly, do a full lookup.
+ */
+ hfs_unlock (cp);
+
+ vnode_put(vp);
+ goto lookup;
+ }
+
/*
* Get an updated descriptor
*/
desc.cd_encoding = 0;
desc.cd_cnid = 0;
desc.cd_flags = S_ISDIR(cp->c_mode) ? CD_ISDIR : 0;
-
+
+ /*
+ * 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);
- if (cat_lookup(VTOHFS(vp), &desc, 0, &desc, NULL, NULL, NULL) == 0)
- replace_desc(cp, &desc);
+
+ error = cat_lookup(VTOHFS(vp), &desc, 0, 0, &desc, &lookup_attr, NULL, NULL);
+
hfs_systemfile_unlock(VTOHFS(dvp), lockflags);
- }
- hfs_unlock(cp);
- }
-#if NAMEDRSRCFORK
- /*
- * Check if caller wants the resource fork but utilized
- * the legacy "file/rsrc" access path.
- *
- * This is deprecated behavior and support for it will not
- * be allowed beyond case insensitive HFS+ and even that
- * support will be removed in the next major OS release.
- */
- if ((dvp != vp) &&
- ((flags & ISLASTCN) == 0) &&
- vnode_isreg(vp) &&
- (cnp->cn_nameptr[cnp->cn_namelen] == '/') &&
- (bcmp(&cnp->cn_nameptr[cnp->cn_namelen+1], "rsrc", 5) == 0) &&
- ((VTOHFS(vp)->hfs_flags & (HFS_STANDARD | HFS_CASE_SENSITIVE)) == 0)) {
- cnp->cn_consume = 5;
- cnp->cn_flags |= CN_WANTSRSRCFORK | ISLASTCN | NOCACHE;
- cnp->cn_flags &= ~MAKEENTRY;
- hfs_lock(cp, HFS_FORCE_LOCK);
- if ((cp->c_flag & C_WARNED_RSRC) == 0) {
- cp->c_flag |= C_WARNED_RSRC;
- printf("%.200s: file access by '/rsrc' was deprecated in 10.4\n", cnp->cn_nameptr);
+ /*
+ * 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;
+ }
+ }
}
- hfs_unlock(cp);
- }
-#endif
- return (error);
+ 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:
/*
*/
cnode_locked = 0;
- error = hfs_lookup(dvp, vpp, cnp, &cnode_locked);
+ error = hfs_lookup(dvp, vpp, cnp, &cnode_locked, force_casesensitive_lookup);
if (cnode_locked)
hfs_unlock(VTOC(*vpp));
exit:
+ {
+ uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread());
+
+ /*
+ * 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 (__improbable(ut->uu_lowpri_window)) {
+ throttle_lowpri_io(1);
+ }
+ }
+
return (error);
}
projects / apple / xnu.git / blobdiff