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[apple/xnu.git] / bsd / vfs / vfs_lookup.c
diff --git a/bsd/vfs/vfs_lookup.c b/bsd/vfs/vfs_lookup.c
index 553bb41f9805fb71214ecfa8d26111d0d5fa1009..ccee2e1c59a14ce37e65329d4793d7632e4f071e 100644 (file)
--- a/bsd/vfs/vfs_lookup.c
+++ b/bsd/vfs/vfs_lookup.c
@@ -1,5 +1,5 @@
 /*
 /*
- * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2015 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -88,9 +88,9 @@
 #include <sys/unistd.h>                /* For _PC_NAME_MAX */
 #include <sys/uio_internal.h>
 #include <sys/kauth.h>
 #include <sys/unistd.h>                /* For _PC_NAME_MAX */
 #include <sys/uio_internal.h>
 #include <sys/kauth.h>
-
+#include <kern/kalloc.h>
 #include <security/audit/audit.h>
 #include <security/audit/audit.h>
-
+#include <sys/dtrace.h>        /* to get the prototype for strstr() in sys/dtrace_glue.h */
 #if CONFIG_MACF
 #include <security/mac_framework.h>
 #endif
 #if CONFIG_MACF
 #include <security/mac_framework.h>
 #endif
@@ -105,12 +105,26 @@
 #define VOLFS_MIN_PATH_LEN  9
 
 
 #define VOLFS_MIN_PATH_LEN  9
 
 
-static void kdebug_lookup(struct vnode *dp, struct componentname *cnp);
-
 #if CONFIG_VOLFS
 static int vfs_getrealpath(const char * path, char * realpath, size_t bufsize, vfs_context_t ctx);
 #if CONFIG_VOLFS
 static int vfs_getrealpath(const char * path, char * realpath, size_t bufsize, vfs_context_t ctx);
+#define MAX_VOLFS_RESTARTS 5
+#endif
+
+static int             lookup_traverse_mountpoints(struct nameidata *ndp, struct componentname *cnp, vnode_t dp, int vbusyflags, vfs_context_t ctx);
+static int             lookup_handle_symlink(struct nameidata *ndp, vnode_t *new_dp, vfs_context_t ctx);
+static int             lookup_authorize_search(vnode_t dp, struct componentname *cnp, int dp_authorized_in_cache, vfs_context_t ctx);
+static void            lookup_consider_update_cache(vnode_t dvp, vnode_t vp, struct componentname *cnp, int nc_generation);
+static int             lookup_handle_found_vnode(struct nameidata *ndp, struct componentname *cnp, int rdonly, 
+                       int vbusyflags, int *keep_going, int nc_generation,
+                       int wantparent, int atroot, vfs_context_t ctx);
+static int             lookup_handle_emptyname(struct nameidata *ndp, struct componentname *cnp, int wantparent);
+
+#if NAMEDRSRCFORK
+static int             lookup_handle_rsrc_fork(vnode_t dp, struct nameidata *ndp, struct componentname *cnp, int wantparent, vfs_context_t ctx);
 #endif
 
 #endif
 
+
+
 /*
  * Convert a pathname into a pointer to a locked inode.
  *
 /*
  * Convert a pathname into a pointer to a locked inode.
  *
@@ -150,12 +164,10 @@ int
 namei(struct nameidata *ndp)
 {
        struct filedesc *fdp;   /* pointer to file descriptor state */
 namei(struct nameidata *ndp)
 {
        struct filedesc *fdp;   /* pointer to file descriptor state */
-       char *cp;               /* pointer into pathname argument */
        struct vnode *dp;       /* the directory we are searching */
        struct vnode *usedvp = ndp->ni_dvp;  /* store pointer to vp in case we must loop due to
                                                                                        heavy vnode pressure */
        u_long cnpflags = ndp->ni_cnd.cn_flags; /* store in case we have to restore after loop */
        struct vnode *dp;       /* the directory we are searching */
        struct vnode *usedvp = ndp->ni_dvp;  /* store pointer to vp in case we must loop due to
                                                                                        heavy vnode pressure */
        u_long cnpflags = ndp->ni_cnd.cn_flags; /* store in case we have to restore after loop */
-       uio_t auio;
        int error;
        struct componentname *cnp = &ndp->ni_cnd;
        vfs_context_t ctx = cnp->cn_context;
        int error;
        struct componentname *cnp = &ndp->ni_cnd;
        vfs_context_t ctx = cnp->cn_context;
@@ -164,8 +176,13 @@ namei(struct nameidata *ndp)
 /* XXX ut should be from context */
        uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread());
 #endif
 /* XXX ut should be from context */
        uthread_t ut = (struct uthread *)get_bsdthread_info(current_thread());
 #endif
-       char *tmppn;
-       char uio_buf[ UIO_SIZEOF(1) ];
+
+#if CONFIG_VOLFS
+       int volfs_restarts = 0;
+#endif
+       size_t bytes_copied = 0;
+
+       fdp = p->p_fd;
 
 #if DIAGNOSTIC
        if (!vfs_context_ucred(ctx) || !p)
 
 #if DIAGNOSTIC
        if (!vfs_context_ucred(ctx) || !p)
@@ -175,7 +192,35 @@ namei(struct nameidata *ndp)
        if (cnp->cn_flags & OPMASK)
                panic ("namei: flags contaminated with nameiops");
 #endif
        if (cnp->cn_flags & OPMASK)
                panic ("namei: flags contaminated with nameiops");
 #endif
-       fdp = p->p_fd;
+
+       /*
+        * A compound VNOP found something that needs further processing:
+        * either a trigger vnode, a covered directory, or a symlink.
+        */
+       if (ndp->ni_flag & NAMEI_CONTLOOKUP) {
+               int rdonly, vbusyflags, keep_going, wantparent;
+
+               rdonly = cnp->cn_flags & RDONLY;
+               vbusyflags = ((cnp->cn_flags & CN_NBMOUNTLOOK) != 0) ? LK_NOWAIT : 0;
+               keep_going = 0;
+               wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
+
+               ndp->ni_flag &= ~(NAMEI_CONTLOOKUP);
+
+               error = lookup_handle_found_vnode(ndp, &ndp->ni_cnd, rdonly, vbusyflags, 
+                               &keep_going, ndp->ni_ncgeneration, wantparent, 0, ctx);
+               if (error)
+                       goto out_drop;
+               if (keep_going) {
+                       if ((cnp->cn_flags & ISSYMLINK) == 0) {
+                               panic("We need to keep going on a continued lookup, but for vp type %d (tag %d)\n", ndp->ni_vp->v_type, ndp->ni_vp->v_tag);
+                       }
+                       goto continue_symlink;
+               }
+
+               return 0;
+
+       }
 
 vnode_recycled:
 
 
 vnode_recycled:
 
@@ -198,10 +243,10 @@ vnode_recycled:
 retry_copy:
        if (UIO_SEG_IS_USER_SPACE(ndp->ni_segflg)) {
                error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
 retry_copy:
        if (UIO_SEG_IS_USER_SPACE(ndp->ni_segflg)) {
                error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf,
-                           cnp->cn_pnlen, (size_t *)&ndp->ni_pathlen);
+                           cnp->cn_pnlen, &bytes_copied);
        } else {
                error = copystr(CAST_DOWN(void *, ndp->ni_dirp), cnp->cn_pnbuf,
        } else {
                error = copystr(CAST_DOWN(void *, ndp->ni_dirp), cnp->cn_pnbuf,
-                           cnp->cn_pnlen, (size_t *)&ndp->ni_pathlen);
+                           cnp->cn_pnlen, &bytes_copied);
        }
        if (error == ENAMETOOLONG && !(cnp->cn_flags & HASBUF)) {
                MALLOC_ZONE(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
        }
        if (error == ENAMETOOLONG && !(cnp->cn_flags & HASBUF)) {
                MALLOC_ZONE(cnp->cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
@@ -212,11 +257,24 @@ retry_copy:
 
                cnp->cn_flags |= HASBUF;
                cnp->cn_pnlen = MAXPATHLEN;
 
                cnp->cn_flags |= HASBUF;
                cnp->cn_pnlen = MAXPATHLEN;
+               bytes_copied = 0;
                
                goto retry_copy;
        }
        if (error)
                goto error_out;
                
                goto retry_copy;
        }
        if (error)
                goto error_out;
+       ndp->ni_pathlen = bytes_copied;
+       bytes_copied = 0;
+
+       /*
+        * Since the name cache may contain positive entries of
+        * the incorrect case, force lookup() to bypass the cache
+        * and call directly into the filesystem for each path
+        * component. Note: the FS may still consult the cache,
+        * but can apply rules to validate the results.
+        */
+       if (proc_is_forcing_hfs_case_sensitivity(p))
+               cnp->cn_flags |= CN_SKIPNAMECACHE;
 
 #if CONFIG_VOLFS
        /*
 
 #if CONFIG_VOLFS
        /*
@@ -310,149 +368,501 @@ retry_copy:
        ndp->ni_vp  = NULLVP;
 
        for (;;) {
        ndp->ni_vp  = NULLVP;
 
        for (;;) {
-               int need_newpathbuf;
-               u_int linklen;
+#if CONFIG_MACF
+               /*
+                * Give MACF policies a chance to reject the lookup
+                * before performing any filesystem operations.
+                * This hook is called before resolving the path and
+                * again each time a symlink is encountered.
+                * NB: policies receive path information as supplied
+                *     by the caller and thus cannot be trusted.
+                */
+               error = mac_vnode_check_lookup_preflight(ctx, dp, cnp->cn_nameptr, cnp->cn_namelen);
+               if (error) {
+                       goto error_out;
+               }
+#endif
 
                ndp->ni_startdir = dp;
 
                if ( (error = lookup(ndp)) ) {
                        goto error_out;
                }
 
                ndp->ni_startdir = dp;
 
                if ( (error = lookup(ndp)) ) {
                        goto error_out;
                }
+
                /*
                 * Check for symbolic link
                 */
                if ((cnp->cn_flags & ISSYMLINK) == 0) {
                        return (0);
                }
                /*
                 * Check for symbolic link
                 */
                if ((cnp->cn_flags & ISSYMLINK) == 0) {
                        return (0);
                }
-#ifndef __LP64__
-               if ((cnp->cn_flags & FSNODELOCKHELD)) {
-                       cnp->cn_flags &= ~FSNODELOCKHELD;
-                       unlock_fsnode(ndp->ni_dvp, NULL);
-               }       
-#endif /* __LP64__ */
-
-               if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
-                       error = ELOOP;
+
+continue_symlink:
+               /* Gives us a new path to process, and a starting dir */
+               error = lookup_handle_symlink(ndp, &dp, ctx);
+               if (error != 0) {
                        break;
                }
                        break;
                }
-#if CONFIG_MACF
-               if ((error = mac_vnode_check_readlink(ctx, ndp->ni_vp)) != 0)
-                       break;
-#endif /* MAC */
-               if (ndp->ni_pathlen > 1 || !(cnp->cn_flags & HASBUF))
-                       need_newpathbuf = 1;
-               else
-                       need_newpathbuf = 0;
+       }
+       /*
+        * only come here if we fail to handle a SYMLINK...
+        * if either ni_dvp or ni_vp is non-NULL, then
+        * we need to drop the iocount that was picked
+        * up in the lookup routine
+        */
+out_drop:
+       if (ndp->ni_dvp)
+               vnode_put(ndp->ni_dvp);
+       if (ndp->ni_vp)
+               vnode_put(ndp->ni_vp);
+ error_out:
+       if ( (cnp->cn_flags & HASBUF) ) {
+               cnp->cn_flags &= ~HASBUF;
+               FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
+       }
+       cnp->cn_pnbuf = NULL;
+       ndp->ni_vp = NULLVP;
+       ndp->ni_dvp = NULLVP;
 
 
-               if (need_newpathbuf) {
-                       MALLOC_ZONE(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
-                       if (cp == NULL) {
-                               error = ENOMEM;
-                               break;
-                       }
-               } else {
-                       cp = cnp->cn_pnbuf;
+#if CONFIG_VOLFS
+       /*
+        * Deal with volfs fallout.  
+        *
+        * At this point, if we were originally given a volfs path that
+        * looks like /.vol/123/456, then we would have had to convert it into
+        * a full path.  Assuming that part worked properly, we will now attempt
+        * to conduct a lookup of the item in the namespace.  Under normal 
+        * circumstances, if a user looked up /tmp/foo and it was not there, it 
+        * would be permissible to return ENOENT.  
+        *
+        * However, we may not want to do that here.  Specifically, the volfs path
+        * uniquely identifies a certain item in the namespace regardless of where it
+        * lives.  If the item has moved in between the time we constructed the
+        * path and now, when we're trying to do a lookup/authorization on the full
+        * path, we may have gotten an ENOENT.  
+        *
+        * At this point we can no longer tell if the path no longer exists 
+        * or if the item in question no longer exists. It could have been renamed 
+        * away, in which case the /.vol identifier is still valid. 
+        * 
+        * Do this dance a maximum of MAX_VOLFS_RESTARTS times.
+        */
+       if ((error == ENOENT) && (ndp->ni_cnd.cn_flags & CN_VOLFSPATH)) {
+               if (volfs_restarts < MAX_VOLFS_RESTARTS) {
+                       volfs_restarts++;
+                       goto vnode_recycled;
                }
                }
-               auio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ, &uio_buf[0], sizeof(uio_buf));
+       }
+#endif
 
 
-               uio_addiov(auio, CAST_USER_ADDR_T(cp), MAXPATHLEN);
+       if (error == ERECYCLE){
+               /* vnode was recycled underneath us. re-drive lookup to start at 
+                  the beginning again, since recycling invalidated last lookup*/
+               ndp->ni_cnd.cn_flags = cnpflags;
+               ndp->ni_dvp = usedvp;
+               goto vnode_recycled;
+       }
 
 
-               error = VNOP_READLINK(ndp->ni_vp, auio, ctx);
-               if (error) {
-                       if (need_newpathbuf)
-                               FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
-                       break;
-               }
 
 
-               /* 
-                * Safe to set unsigned with a [larger] signed type here
-                * because 0 <= uio_resid <= MAXPATHLEN and MAXPATHLEN
-                * is only 1024.
+       return (error);
+}
+
+int            
+namei_compound_available(vnode_t dp, struct nameidata *ndp)
+{
+       if ((ndp->ni_flag & NAMEI_COMPOUNDOPEN) != 0) {
+               return vnode_compound_open_available(dp);
+       }
+
+       return 0;
+}
+
+static int
+lookup_authorize_search(vnode_t dp, struct componentname *cnp, int dp_authorized_in_cache, vfs_context_t ctx)
+{
+#if !CONFIG_MACF
+#pragma unused(cnp)
+#endif
+
+       int error;
+
+       if (!dp_authorized_in_cache) {
+               error = vnode_authorize(dp, NULL, KAUTH_VNODE_SEARCH, ctx);
+               if (error)
+                       return error;
+       }
+#if CONFIG_MACF
+       error = mac_vnode_check_lookup(ctx, dp, cnp);
+       if (error)
+               return error;
+#endif /* CONFIG_MACF */
+
+       return 0;
+}
+
+static void 
+lookup_consider_update_cache(vnode_t dvp, vnode_t vp, struct componentname *cnp, int nc_generation) 
+{
+       int isdot_or_dotdot;
+       isdot_or_dotdot = (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') || (cnp->cn_flags & ISDOTDOT);
+
+       if (vp->v_name == NULL || vp->v_parent == NULLVP) {
+               int  update_flags = 0;
+
+               if (isdot_or_dotdot == 0) {
+                       if (vp->v_name == NULL)
+                               update_flags |= VNODE_UPDATE_NAME;
+                       if (dvp != NULLVP && vp->v_parent == NULLVP)
+                               update_flags |= VNODE_UPDATE_PARENT;
+
+                       if (update_flags)
+                               vnode_update_identity(vp, dvp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, update_flags);
+               }
+       }
+       if ( (cnp->cn_flags & MAKEENTRY) && (vp->v_flag & VNCACHEABLE) && LIST_FIRST(&vp->v_nclinks) == NULL) {
+               /*
+                * missing from name cache, but should
+                * be in it... this can happen if volfs
+                * causes the vnode to be created or the
+                * name cache entry got recycled but the
+                * vnode didn't...
+                * check to make sure that ni_dvp is valid
+                * cache_lookup_path may return a NULL
+                * do a quick check to see if the generation of the
+                * directory matches our snapshot... this will get
+                * rechecked behind the name cache lock, but if it
+                * already fails to match, no need to go any further
                 */
                 */
-               linklen = MAXPATHLEN - (u_int)uio_resid(auio);
-               if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
-                       if (need_newpathbuf)
-                               FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
+               if (dvp != NULLVP && (nc_generation == dvp->v_nc_generation) && (!isdot_or_dotdot))
+                       cache_enter_with_gen(dvp, vp, cnp, nc_generation);
+       }
 
 
-                       error = ENAMETOOLONG;
+}
+
+#if NAMEDRSRCFORK
+/*
+ * Can change ni_dvp and ni_vp.  On success, returns with iocounts on stream vnode (always) and
+ * data fork if requested.  On failure, returns with iocount data fork (always) and its parent directory 
+ * (if one was provided).
+ */
+static int
+lookup_handle_rsrc_fork(vnode_t dp, struct nameidata *ndp, struct componentname *cnp, int wantparent, vfs_context_t ctx)
+{
+       vnode_t svp = NULLVP;
+       enum nsoperation nsop;
+       int nsflags;
+       int error;
+
+       if (dp->v_type != VREG) {
+               error = ENOENT;
+               goto out;
+       }
+       switch (cnp->cn_nameiop) {
+               case DELETE:
+                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
+                               nsop = NS_DELETE;
+                       } else {
+                               error = EPERM;
+                               goto out;
+                       }
+                       break;
+               case CREATE:
+                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
+                               nsop = NS_CREATE;
+                       } else {
+                               error = EPERM;
+                               goto out;
+                       }
                        break;
                        break;
+               case LOOKUP:
+                       /* Make sure our lookup of "/..namedfork/rsrc" is allowed. */
+                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
+                               nsop = NS_OPEN;
+                       } else {
+                               error = EPERM;
+                               goto out;
+                       }
+                       break;
+               default:
+                       error = EPERM;
+                       goto out;
+       }
+
+       nsflags = 0;
+       if (cnp->cn_flags & CN_RAW_ENCRYPTED)
+               nsflags |= NS_GETRAWENCRYPTED;
+
+       /* Ask the file system for the resource fork. */
+       error = vnode_getnamedstream(dp, &svp, XATTR_RESOURCEFORK_NAME, nsop, nsflags, ctx);
+
+       /* During a create, it OK for stream vnode to be missing. */
+       if (error == ENOATTR || error == ENOENT) {
+               error = (nsop == NS_CREATE) ? 0 : ENOENT;
+       }               
+       if (error) {
+               goto out;
+       }
+       /* The "parent" of the stream is the file. */
+       if (wantparent) {
+               if (ndp->ni_dvp) {
+                       vnode_put(ndp->ni_dvp);
                }
                }
-               if (need_newpathbuf) {
-                       long len = cnp->cn_pnlen;
+               ndp->ni_dvp = dp;
+       } else {
+               vnode_put(dp);
+       }
+       ndp->ni_vp = svp;  /* on create this may be null */
 
 
-                       tmppn = cnp->cn_pnbuf;
-                       bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
-                       cnp->cn_pnbuf = cp;
-                       cnp->cn_pnlen = MAXPATHLEN;
+       /* Restore the truncated pathname buffer (for audits). */
+       if (ndp->ni_pathlen == 1 && ndp->ni_next[0] == '\0') {
+               ndp->ni_next[0] = '/';
+       }
+       cnp->cn_flags  &= ~MAKEENTRY;
 
 
-                       if ( (cnp->cn_flags & HASBUF) )
-                               FREE_ZONE(tmppn, len, M_NAMEI);
-                       else
-                               cnp->cn_flags |= HASBUF;
-               } else
-                       cnp->cn_pnbuf[linklen] = '\0';
+       return 0;
+out:
+       return error;
+}
+#endif /* NAMEDRSRCFORK */
 
 
-               ndp->ni_pathlen += linklen;
-               cnp->cn_nameptr = cnp->cn_pnbuf;
+/*
+ * iocounts in:
+ *     --One on ni_vp.  One on ni_dvp if there is more path, or we didn't come through the
+ *     cache, or we came through the cache and the caller doesn't want the parent.
+ *
+ * iocounts out:
+ *     --Leaves us in the correct state for the next step, whatever that might be.
+ *     --If we find a symlink, returns with iocounts on both ni_vp and ni_dvp.
+ *     --If we are to look up another component, then we have an iocount on ni_vp and
+ *     nothing else.  
+ *     --If we are done, returns an iocount on ni_vp, and possibly on ni_dvp depending on nameidata flags.
+ *     --In the event of an error, may return with ni_dvp NULL'ed out (in which case, iocount
+ *     was dropped).
+ */
+static int             
+lookup_handle_found_vnode(struct nameidata *ndp, struct componentname *cnp, int rdonly, 
+               int vbusyflags, int *keep_going, int nc_generation,
+               int wantparent, int atroot, vfs_context_t ctx)
+{
+       vnode_t dp;
+       int error;
+       char *cp;
 
 
-               /*
-                * starting point for 'relative'
-                * symbolic link path
-                */
-               dp = ndp->ni_dvp;
-               /*
-                * get rid of references returned via 'lookup'
-                */
-               vnode_put(ndp->ni_vp);
-               vnode_put(ndp->ni_dvp);
+       dp = ndp->ni_vp;
+       *keep_going = 0;
+
+       if (ndp->ni_vp == NULLVP) {
+               panic("NULL ni_vp in %s\n", __FUNCTION__);
+       }
+
+       if (atroot) {
+               goto nextname;
+       }
+
+       /*
+        * Take into account any additional components consumed by
+        * the underlying filesystem.
+        */
+       if (cnp->cn_consume > 0) {
+               cnp->cn_nameptr += cnp->cn_consume;
+               ndp->ni_next += cnp->cn_consume;
+               ndp->ni_pathlen -= cnp->cn_consume;
+               cnp->cn_consume = 0;
+       } else {
+               lookup_consider_update_cache(ndp->ni_dvp, dp, cnp, nc_generation);
+       }
+
+       /*
+        * Check to see if the vnode has been mounted on...
+        * if so find the root of the mounted file system.
+        * Updates ndp->ni_vp.
+        */
+       error = lookup_traverse_mountpoints(ndp, cnp, dp, vbusyflags, ctx);
+       dp = ndp->ni_vp;
+       if (error) {
+               goto out;
+       }
+
+#if CONFIG_MACF
+       if (vfs_flags(vnode_mount(dp)) & MNT_MULTILABEL) {
+               error = vnode_label(vnode_mount(dp), NULL, dp, NULL, 0, ctx);
+               if (error)
+                       goto out;
+       }
+#endif
+
+       /*
+        * Check for symbolic link
+        */
+       if ((dp->v_type == VLNK) &&
+           ((cnp->cn_flags & FOLLOW) || (ndp->ni_flag & NAMEI_TRAILINGSLASH) || *ndp->ni_next == '/')) {
+               cnp->cn_flags |= ISSYMLINK;
+               *keep_going = 1;
+               return (0);
+       }
+
+       /*
+        * Check for bogus trailing slashes.
+        */
+       if ((ndp->ni_flag & NAMEI_TRAILINGSLASH)) {
+               if (dp->v_type != VDIR) {
+                       error = ENOTDIR;
+                       goto out;
+               }
+               ndp->ni_flag &= ~(NAMEI_TRAILINGSLASH);
+       } 
+
+#if NAMEDSTREAMS
+       /* 
+        * Deny namei/lookup requests to resolve paths that point to shadow files.
+        * Access to shadow files must be conducted by explicit calls to VNOP_LOOKUP
+        * directly, and not use lookup/namei
+        */
+       if (vnode_isshadow (dp)) {
+               error = ENOENT;
+               goto out;
+       }
+#endif
 
 
-               ndp->ni_vp = NULLVP;
+nextname:
+       /*
+        * Not a symbolic link.  If more pathname,
+        * continue at next component, else return.
+        *
+        * Definitely have a dvp if there's another slash 
+        */
+       if (*ndp->ni_next == '/') {
+               cnp->cn_nameptr = ndp->ni_next + 1;
+               ndp->ni_pathlen--;
+               while (*cnp->cn_nameptr == '/') {
+                       cnp->cn_nameptr++;
+                       ndp->ni_pathlen--;
+               }
+
+               cp = cnp->cn_nameptr;
+               vnode_put(ndp->ni_dvp);
                ndp->ni_dvp = NULLVP;
 
                ndp->ni_dvp = NULLVP;
 
-               /*
-                * Check if symbolic link restarts us at the root
+               if (*cp == '\0') {
+                       goto emptyname;
+               }
+
+               *keep_going = 1;
+               return 0;
+       }
+                                 
+       /*
+        * Disallow directory write attempts on read-only file systems.
+        */
+       if (rdonly &&
+           (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
+               error = EROFS;
+               goto out;
+       }
+       
+       /* If SAVESTART is set, we should have a dvp */
+       if (cnp->cn_flags & SAVESTART) {
+               /*      
+                * note that we already hold a reference
+                * on both dp and ni_dvp, but for some reason
+                * can't get another one... in this case we
+                * need to do vnode_put on dp in 'bad2'
                 */
                 */
-               if (*(cnp->cn_nameptr) == '/') {
-                       while (*(cnp->cn_nameptr) == '/') {
-                               cnp->cn_nameptr++;
-                               ndp->ni_pathlen--;
-                       }
-                       if ((dp = ndp->ni_rootdir) == NULLVP) {
-                               error = ENOENT;
-                               goto error_out;
-                       }
+               if ( (vnode_get(ndp->ni_dvp)) ) {
+                       error = ENOENT;
+                       goto out;
                }
                }
+               ndp->ni_startdir = ndp->ni_dvp;
+       }
+       if (!wantparent && ndp->ni_dvp) {
+               vnode_put(ndp->ni_dvp);
+               ndp->ni_dvp = NULLVP;
+       }
+
+       if (cnp->cn_flags & AUDITVNPATH1)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE1);
+       else if (cnp->cn_flags & AUDITVNPATH2)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE2);
+
+#if NAMEDRSRCFORK
+       /*
+        * Caller wants the resource fork.
+        */
+       if ((cnp->cn_flags & CN_WANTSRSRCFORK) && (dp != NULLVP)) {
+               error = lookup_handle_rsrc_fork(dp, ndp, cnp, wantparent, ctx);
+               if (error != 0)
+                       goto out;
+
+               dp = ndp->ni_vp;
        }
        }
+#endif
+       if (kdebug_enable)
+               kdebug_lookup(ndp->ni_vp, cnp);
+
+       return 0;
+
+emptyname:
+       error = lookup_handle_emptyname(ndp, cnp, wantparent);
+       if (error != 0) 
+               goto out;
+
+       return 0;
+out:
+       return error;
+
+}
+
+/*
+ * Comes in iocount on ni_vp.  May overwrite ni_dvp, but doesn't interpret incoming value.
+ */
+static int 
+lookup_handle_emptyname(struct nameidata *ndp, struct componentname *cnp, int wantparent)
+{
+       vnode_t dp;
+       int error = 0;
+
+       dp = ndp->ni_vp;
+       cnp->cn_namelen = 0;
        /*
        /*
-        * only come here if we fail to handle a SYMLINK...
-        * if either ni_dvp or ni_vp is non-NULL, then
-        * we need to drop the iocount that was picked
-        * up in the lookup routine
+        * A degenerate name (e.g. / or "") which is a way of
+        * talking about a directory, e.g. like "/." or ".".
         */
         */
-       if (ndp->ni_dvp)
-               vnode_put(ndp->ni_dvp);
-       if (ndp->ni_vp)
-               vnode_put(ndp->ni_vp);
- error_out:
-       if ( (cnp->cn_flags & HASBUF) ) {
-               cnp->cn_flags &= ~HASBUF;
-               FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
+       if (dp->v_type != VDIR) {
+               error = ENOTDIR;
+               goto out;
        }
        }
-       cnp->cn_pnbuf = NULL;
-       ndp->ni_vp = NULLVP;
-       if (error == ERECYCLE){
-               /* vnode was recycled underneath us. re-drive lookup to start at 
-                  the beginning again, since recycling invalidated last lookup*/
-               ndp->ni_cnd.cn_flags = cnpflags;
-               ndp->ni_dvp = usedvp;
-               goto vnode_recycled;
+       if (cnp->cn_nameiop != LOOKUP) {
+               error = EISDIR;
+               goto out;
+       }
+       if (wantparent) {
+               /*      
+                * note that we already hold a reference
+                * on dp, but for some reason can't
+                * get another one... in this case we
+                * need to do vnode_put on dp in 'bad'
+                */
+               if ( (vnode_get(dp)) ) {
+                       error = ENOENT;
+                       goto out;
+               }
+               ndp->ni_dvp = dp;
        }
        }
+       cnp->cn_flags &= ~ISDOTDOT;
+       cnp->cn_flags |= ISLASTCN;
+       ndp->ni_next = cnp->cn_nameptr;
+       ndp->ni_vp = dp;
 
 
+       if (cnp->cn_flags & AUDITVNPATH1)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE1);
+       else if (cnp->cn_flags & AUDITVNPATH2)
+               AUDIT_ARG(vnpath, dp, ARG_VNODE2);
+       if (cnp->cn_flags & SAVESTART)
+               panic("lookup: SAVESTART");
 
 
-       return (error);
+       return 0;
+out:
+       return error;
 }
 }
-
-
 /*
  * Search a pathname.
  * This is a very central and rather complicated routine.
 /*
  * Search a pathname.
  * This is a very central and rather complicated routine.
@@ -515,29 +925,24 @@ lookup(struct nameidata *ndp)
        char    *cp;            /* pointer into pathname argument */
        vnode_t         tdp;            /* saved dp */
        vnode_t         dp;             /* the directory we are searching */
        char    *cp;            /* pointer into pathname argument */
        vnode_t         tdp;            /* saved dp */
        vnode_t         dp;             /* the directory we are searching */
-       mount_t         mp;             /* mount table entry */
        int docache = 1;                /* == 0 do not cache last component */
        int wantparent;                 /* 1 => wantparent or lockparent flag */
        int rdonly;                     /* lookup read-only flag bit */
        int docache = 1;                /* == 0 do not cache last component */
        int wantparent;                 /* 1 => wantparent or lockparent flag */
        int rdonly;                     /* lookup read-only flag bit */
-       int trailing_slash = 0;
        int dp_authorized = 0;
        int error = 0;
        struct componentname *cnp = &ndp->ni_cnd;
        vfs_context_t ctx = cnp->cn_context;
        int dp_authorized = 0;
        int error = 0;
        struct componentname *cnp = &ndp->ni_cnd;
        vfs_context_t ctx = cnp->cn_context;
-       int mounted_on_depth = 0;
-       int dont_cache_mp = 0;
-       vnode_t mounted_on_dp = NULLVP;
-       int current_mount_generation = 0;
        int vbusyflags = 0;
        int nc_generation = 0;
        vnode_t last_dp = NULLVP;
        int vbusyflags = 0;
        int nc_generation = 0;
        vnode_t last_dp = NULLVP;
+       int keep_going;
+       int atroot;
 
        /*
         * Setup: break out flag bits into variables.
         */
 
        /*
         * Setup: break out flag bits into variables.
         */
-       if (cnp->cn_flags & (NOCACHE | DOWHITEOUT)) {
-               if ((cnp->cn_flags & NOCACHE) || (cnp->cn_nameiop == DELETE))
-                       docache = 0;
+       if (cnp->cn_flags & NOCACHE) {
+               docache = 0;
        }
        wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
        rdonly = cnp->cn_flags & RDONLY;
        }
        wantparent = cnp->cn_flags & (LOCKPARENT | WANTPARENT);
        rdonly = cnp->cn_flags & RDONLY;
@@ -557,12 +962,19 @@ lookup(struct nameidata *ndp)
                        error = ENOENT;
                        goto bad;
                }
                        error = ENOENT;
                        goto bad;
                }
-               goto emptyname;
+               ndp->ni_vp = dp;
+               error = lookup_handle_emptyname(ndp, cnp, wantparent);
+               if (error) {
+                       goto bad;
+               }
+
+               return 0;
        }
 dirloop: 
        }
 dirloop: 
+       atroot = 0;
        ndp->ni_vp = NULLVP;
 
        ndp->ni_vp = NULLVP;
 
-       if ( (error = cache_lookup_path(ndp, cnp, dp, ctx, &trailing_slash, &dp_authorized, last_dp)) ) {
+       if ( (error = cache_lookup_path(ndp, cnp, dp, ctx, &dp_authorized, last_dp)) ) {
                dp = NULLVP;
                goto bad;
        }
                dp = NULLVP;
                goto bad;
        }
@@ -602,6 +1014,40 @@ dirloop:
         *    .. in the other file system.
         */
        if ( (cnp->cn_flags & ISDOTDOT) ) {
         *    .. in the other file system.
         */
        if ( (cnp->cn_flags & ISDOTDOT) ) {
+               /*
+                * if this is a chroot'ed process, check if the current
+                * directory is still a subdirectory of the process's
+                * root directory.
+                */
+               if (ndp->ni_rootdir && (ndp->ni_rootdir != rootvnode) &&
+                   dp !=  ndp->ni_rootdir) {
+                       int sdir_error;
+                       int is_subdir = FALSE;
+
+                       sdir_error = vnode_issubdir(dp, ndp->ni_rootdir,
+                           &is_subdir, vfs_context_kernel());
+
+                       /*
+                        * If we couldn't determine if dp is a subdirectory of
+                        * ndp->ni_rootdir (sdir_error != 0), we let the request
+                        * proceed.
+                        */
+                       if (!sdir_error && !is_subdir) {
+                               vnode_put(dp);
+                               dp = ndp->ni_rootdir;
+                               /*
+                                * There's a ref on the process's root directory
+                                * but we can't use vnode_getwithref here as
+                                * there is nothing preventing that ref being
+                                * released by another thread.
+                                */
+                               if (vnode_get(dp)) {
+                                       error = ENOENT;
+                                       goto bad;
+                               }
+                       }
+               }
+
                for (;;) {
                        if (dp == ndp->ni_rootdir || dp == rootvnode) {
                                ndp->ni_dvp = dp;
                for (;;) {
                        if (dp == ndp->ni_rootdir || dp == rootvnode) {
                                ndp->ni_dvp = dp;
@@ -618,7 +1064,8 @@ dirloop:
                                        error = ENOENT;
                                        goto bad;
                                }
                                        error = ENOENT;
                                        goto bad;
                                }
-                               goto nextname;
+                               atroot = 1;
+                               goto returned_from_lookup_path;
                        }
                        if ((dp->v_flag & VROOT) == 0 ||
                            (cnp->cn_flags & NOCROSSMOUNT))
                        }
                        if ((dp->v_flag & VROOT) == 0 ||
                            (cnp->cn_flags & NOCROSSMOUNT))
@@ -653,41 +1100,66 @@ unionlookup:
                goto lookup_error;
        }
        if ( (cnp->cn_flags & DONOTAUTH) != DONOTAUTH ) {
                goto lookup_error;
        }
        if ( (cnp->cn_flags & DONOTAUTH) != DONOTAUTH ) {
-               if (!dp_authorized) {
-                       error = vnode_authorize(dp, NULL, KAUTH_VNODE_SEARCH, ctx);
-                       if (error)
-                               goto lookup_error;
-               }
-#if CONFIG_MACF
-               error = mac_vnode_check_lookup(ctx, dp, cnp);
-               if (error)
+               error = lookup_authorize_search(dp, cnp, dp_authorized, ctx);
+               if (error) {
                        goto lookup_error;
                        goto lookup_error;
-#endif /* CONFIG_MACF */
+               }
+       }
+
+       /*
+        * Now that we've authorized a lookup, can bail out if the filesystem
+        * will be doing a batched operation.  Return an iocount on dvp.
+        */
+#if NAMEDRSRCFORK
+       if ((cnp->cn_flags & ISLASTCN) && namei_compound_available(dp, ndp) && !(cnp->cn_flags & CN_WANTSRSRCFORK)) { 
+#else 
+       if ((cnp->cn_flags & ISLASTCN) && namei_compound_available(dp, ndp)) {
+#endif /* NAMEDRSRCFORK */
+               ndp->ni_flag |= NAMEI_UNFINISHED;
+               ndp->ni_ncgeneration = dp->v_nc_generation;
+               return 0;
        }
 
         nc_generation = dp->v_nc_generation;
 
        }
 
         nc_generation = dp->v_nc_generation;
 
-       if ( (error = VNOP_LOOKUP(dp, &ndp->ni_vp, cnp, ctx)) ) {
+       /*
+        * Note: 
+        * Filesystems that support hardlinks may want to call vnode_update_identity
+        * if the lookup operation below will modify the in-core vnode to belong to a new point
+        * in the namespace.  VFS cannot infer whether or not the look up operation makes the vnode
+        * name change or change parents.  Without this, the lookup may make update
+        * filesystem-specific in-core metadata but fail to update the v_parent or v_name
+        * fields in the vnode.  If VFS were to do this, it would be necessary to call
+        * vnode_update_identity on every lookup operation -- expensive!
+        *
+        * However, even with this in place, multiple lookups may occur in between this lookup
+        * and the subsequent vnop, so, at best, we could only guarantee that you would get a
+        * valid path back, and not necessarily the one that you wanted. 
+        *
+        * Example: 
+        * /tmp/a == /foo/b
+        * 
+        * If you are now looking up /foo/b and the vnode for this link represents /tmp/a, 
+        * vnode_update_identity will fix the parentage so that you can get /foo/b back 
+        * through the v_parent chain (preventing you from getting /tmp/b back). It would 
+        * not fix whether or not you should or should not get /tmp/a vs. /foo/b.
+        */
+
+       error = VNOP_LOOKUP(dp, &ndp->ni_vp, cnp, ctx);
+
+       if ( error ) {
 lookup_error:
                if ((error == ENOENT) &&
 lookup_error:
                if ((error == ENOENT) &&
-                   (dp->v_flag & VROOT) && (dp->v_mount != NULL) &&
+                   (dp->v_mount != NULL) &&
                    (dp->v_mount->mnt_flag & MNT_UNION)) {
                    (dp->v_mount->mnt_flag & MNT_UNION)) {
-#ifndef __LP64__
-                       if ((cnp->cn_flags & FSNODELOCKHELD)) {
-                               cnp->cn_flags &= ~FSNODELOCKHELD;
-                               unlock_fsnode(dp, NULL);
-                       }       
-#endif /* __LP64__ */
                        tdp = dp;
                        tdp = dp;
-                       dp = tdp->v_mount->mnt_vnodecovered;
-
+                       error = lookup_traverse_union(tdp, &dp, ctx);
                        vnode_put(tdp);
                        vnode_put(tdp);
-
-                       if ( (vnode_getwithref(dp)) ) {
+                       if (error) {
                                dp = NULLVP;
                                dp = NULLVP;
-                               error = ENOENT;
                                goto bad;
                        }
                                goto bad;
                        }
+
                        ndp->ni_dvp = dp;
                        dp_authorized = 0;
                        goto unionlookup;
                        ndp->ni_dvp = dp;
                        dp_authorized = 0;
                        goto unionlookup;
@@ -699,18 +1171,28 @@ lookup_error:
                if (ndp->ni_vp != NULLVP)
                        panic("leaf should be empty");
 
                if (ndp->ni_vp != NULLVP)
                        panic("leaf should be empty");
 
-               /*
-                * If creating and at end of pathname, then can consider
-                * allowing file to be created.
+#if NAMEDRSRCFORK
+               /* 
+                * At this point, error should be EJUSTRETURN.
+                * 
+                * If CN_WANTSRSRCFORK is set, that implies that the 
+                * underlying filesystem could not find the "parent" of the
+                * resource fork (the data fork), and we are doing a lookup 
+                * for a CREATE event.
+                *
+                * However, this should be converted to an error, as the
+                * failure to find this parent should disallow further
+                * progress to try and acquire a resource fork vnode. 
                 */
                 */
-               if (rdonly) {
-                       error = EROFS;
-                       goto bad;
-               }
-               if ((cnp->cn_flags & ISLASTCN) && trailing_slash && !(cnp->cn_flags & WILLBEDIR)) {
+               if (cnp->cn_flags & CN_WANTSRSRCFORK) {
                        error = ENOENT;
                        goto bad;
                }
                        error = ENOENT;
                        goto bad;
                }
+#endif
+
+               error = lookup_validate_creation_path(ndp);
+               if (error)
+                       goto bad;
                /*
                 * We return with ni_vp NULL to indicate that the entry
                 * doesn't currently exist, leaving a pointer to the
                /*
                 * We return with ni_vp NULL to indicate that the entry
                 * doesn't currently exist, leaving a pointer to the
@@ -731,368 +1213,377 @@ lookup_error:
                return (0);
        }
 returned_from_lookup_path:
                return (0);
        }
 returned_from_lookup_path:
-       dp = ndp->ni_vp;
+       /* We'll always have an iocount on ni_vp when this finishes. */
+       error = lookup_handle_found_vnode(ndp, cnp, rdonly, vbusyflags, &keep_going, nc_generation, wantparent, atroot, ctx);
+       if (error != 0) {
+               goto bad2; 
+       }
 
 
-       /*
-        * Take into account any additional components consumed by
-        * the underlying filesystem.
-        */
-       if (cnp->cn_consume > 0) {
-               cnp->cn_nameptr += cnp->cn_consume;
-               ndp->ni_next += cnp->cn_consume;
-               ndp->ni_pathlen -= cnp->cn_consume;
-               cnp->cn_consume = 0;
-       } else {
-               int isdot_or_dotdot;
-               isdot_or_dotdot = (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') || (cnp->cn_flags & ISDOTDOT);
+       if (keep_going) {
+               dp = ndp->ni_vp;
 
 
-               if (dp->v_name == NULL || dp->v_parent == NULLVP) {
-                       int  update_flags = 0;
+               /* namei() will handle symlinks */
+               if ((dp->v_type == VLNK) &&
+                               ((cnp->cn_flags & FOLLOW) || (ndp->ni_flag & NAMEI_TRAILINGSLASH) || *ndp->ni_next == '/')) {
+                       return 0; 
+               }
 
 
-                       if (isdot_or_dotdot == 0) {
-                               if (dp->v_name == NULL)
-                                       update_flags |= VNODE_UPDATE_NAME;
-                               if (ndp->ni_dvp != NULLVP && dp->v_parent == NULLVP)
-                                       update_flags |= VNODE_UPDATE_PARENT;
+               /*
+                * Otherwise, there's more path to process.  
+                * cache_lookup_path is now responsible for dropping io ref on dp
+                * when it is called again in the dirloop.  This ensures we hold
+                * a ref on dp until we complete the next round of lookup.
+                */
+               last_dp = dp;
 
 
-                               if (update_flags)
-                                       vnode_update_identity(dp, ndp->ni_dvp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, update_flags);
-                       }
-               }
-               if ( (cnp->cn_flags & MAKEENTRY) && (dp->v_flag & VNCACHEABLE) && LIST_FIRST(&dp->v_nclinks) == NULL) {
-                       /*
-                        * missing from name cache, but should
-                        * be in it... this can happen if volfs
-                        * causes the vnode to be created or the
-                        * name cache entry got recycled but the
-                        * vnode didn't...
-                        * check to make sure that ni_dvp is valid
-                        * cache_lookup_path may return a NULL
-                        * do a quick check to see if the generation of the
-                        * directory matches our snapshot... this will get
-                        * rechecked behind the name cache lock, but if it
-                        * already fails to match, no need to go any further
-                        */
-                       if (ndp->ni_dvp != NULLVP && (nc_generation == ndp->ni_dvp->v_nc_generation) && (!isdot_or_dotdot))
-                               cache_enter_with_gen(ndp->ni_dvp, dp, cnp, nc_generation);
-               }
+               goto dirloop;
        }
 
        }
 
-       mounted_on_dp = dp;
-       mounted_on_depth = 0;
-       dont_cache_mp = 0;
-       current_mount_generation = mount_generation;
-       /*
-        * Check to see if the vnode has been mounted on...
-        * if so find the root of the mounted file system.
-        */
-check_mounted_on:
-       if ((dp->v_type == VDIR) && dp->v_mountedhere &&
-            ((cnp->cn_flags & NOCROSSMOUNT) == 0)) {
-         
-               vnode_lock(dp);
-
-               if ((dp->v_type == VDIR) && (mp = dp->v_mountedhere)) {
-                       struct uthread *uth = (struct uthread *)get_bsdthread_info(current_thread());
+       return (0);
+bad2:
+       if (ndp->ni_dvp)
+               vnode_put(ndp->ni_dvp);
 
 
-                       mp->mnt_crossref++;
-                       vnode_unlock(dp);
+       vnode_put(ndp->ni_vp);
+       ndp->ni_vp = NULLVP;
 
 
-                               
-                       if (vfs_busy(mp, vbusyflags)) {
-                               mount_dropcrossref(mp, dp, 0);
-                               if (vbusyflags == LK_NOWAIT) {
-                                       error = ENOENT;
-                                       goto bad2;      
-                               }
-                               goto check_mounted_on;
-                       }
+       if (kdebug_enable)
+               kdebug_lookup(dp, cnp);
+       return (error);
 
 
-                       /*
-                        * XXX - if this is the last component of the
-                        * pathname, and it's either not a lookup operation
-                        * or the NOTRIGGER flag is set for the operation,
-                        * set a uthread flag to let VFS_ROOT() for autofs
-                        * know it shouldn't trigger a mount.
-                        */
-                       if ((cnp->cn_flags & ISLASTCN) &&
-                           (cnp->cn_nameiop != LOOKUP ||
-                            (cnp->cn_flags & NOTRIGGER))) {
-                               uth->uu_notrigger = 1;
-                               dont_cache_mp = 1;
-                       }
-                       error = VFS_ROOT(mp, &tdp, ctx);
-                       /* XXX - clear the uthread flag */
-                       uth->uu_notrigger = 0;
-                       /*
-                        * mount_dropcrossref does a vnode_put
-                        * on dp if the 3rd arg is non-zero
-                        */
-                       mount_dropcrossref(mp, dp, 1);
-                       dp = NULL;
-                       vfs_unbusy(mp);
+bad:
+       if (dp)
+               vnode_put(dp);
+       ndp->ni_vp = NULLVP;
 
 
-                       if (error) {
-                               goto bad2;
-                       }
-                       ndp->ni_vp = dp = tdp;
-                       mounted_on_depth++;
-                       
-                       goto check_mounted_on;
-               } 
-               vnode_unlock(dp);
-       }
+       if (kdebug_enable)
+               kdebug_lookup(dp, cnp);
+       return (error);
+}
 
 
-#if CONFIG_MACF
-       if (vfs_flags(vnode_mount(dp)) & MNT_MULTILABEL) {
-               error = vnode_label(vnode_mount(dp), NULL, dp, NULL, 0, ctx);
-               if (error)
-                       goto bad2;
-       }
-#endif
+/*
+ * Given a vnode in a union mount, traverse to the equivalent
+ * vnode in the underlying mount.
+ */
+int
+lookup_traverse_union(vnode_t dvp, vnode_t *new_dvp, vfs_context_t ctx)
+{
+       char *path = NULL, *pp;
+       const char *name, *np;
+       int len;
+       int error = 0;
+       struct nameidata nd;
+       vnode_t vp = dvp;
 
 
-       if (mounted_on_depth && !dont_cache_mp) {
-               mp = mounted_on_dp->v_mountedhere;
+       *new_dvp = NULL;
 
 
-               if (mp) {
-                       mount_lock_spin(mp);
-                       mp->mnt_realrootvp_vid = dp->v_id;
-                       mp->mnt_realrootvp = dp;
-                       mp->mnt_generation = current_mount_generation;
-                       mount_unlock(mp);
-               }
+       if (vp && vp->v_flag & VROOT) {
+               *new_dvp = vp->v_mount->mnt_vnodecovered;
+               if (vnode_getwithref(*new_dvp))
+                       return ENOENT;
+               return 0;
        }
 
        }
 
-       /*
-        * Check for symbolic link
-        */
-       if ((dp->v_type == VLNK) &&
-           ((cnp->cn_flags & FOLLOW) || trailing_slash || *ndp->ni_next == '/')) {
-               cnp->cn_flags |= ISSYMLINK;
-               return (0);
+       path = (char *) kalloc(MAXPATHLEN);
+       if (path == NULL) {
+               error = ENOMEM;
+               goto done;
        }
 
        /*
        }
 
        /*
-        * Check for bogus trailing slashes.
+        * Walk back up to the mountpoint following the
+        * v_parent chain and build a slash-separated path.
+        * Then lookup that path starting with the covered vnode.
         */
         */
-       if (trailing_slash) {
-               if (dp->v_type != VDIR) {
-                       error = ENOTDIR;
-                       goto bad2;
-               }
-               trailing_slash = 0;
-       }
+       pp = path + (MAXPATHLEN - 1);
+       *pp = '\0';
 
 
-nextname:
-       /*
-        * Not a symbolic link.  If more pathname,
-        * continue at next component, else return.
-        */
-       if (*ndp->ni_next == '/') {
-               cnp->cn_nameptr = ndp->ni_next + 1;
-               ndp->ni_pathlen--;
-               while (*cnp->cn_nameptr == '/') {
-                       cnp->cn_nameptr++;
-                       ndp->ni_pathlen--;
+       while (1) {
+               name = vnode_getname(vp);
+               if (name == NULL) {
+                       printf("lookup_traverse_union: null parent name: .%s\n", pp);
+                       error = ENOENT;
+                       goto done;
                }
                }
-               vnode_put(ndp->ni_dvp);
+               len = strlen(name);
+               if ((len + 1) > (pp - path)) {          // Enough space for this name ?
+                       error = ENAMETOOLONG;
+                       vnode_putname(name);
+                       goto done;
+               }
+               for (np = name + len; len > 0; len--)   // Copy name backwards
+                       *--pp = *--np;
+               vnode_putname(name);
+               vp = vp->v_parent;
+               if (vp == NULLVP || vp->v_flag & VROOT)
+                       break;
+               *--pp = '/';
+       }
 
 
-               cp = cnp->cn_nameptr;
+       /* Evaluate the path in the underlying mount */
+       NDINIT(&nd, LOOKUP, OP_LOOKUP, USEDVP, UIO_SYSSPACE, CAST_USER_ADDR_T(pp), ctx);
+       nd.ni_dvp = dvp->v_mount->mnt_vnodecovered;
+       error = namei(&nd);
+       if (error == 0)
+               *new_dvp = nd.ni_vp;
+       nameidone(&nd);
+done:
+       if (path)
+               kfree(path, MAXPATHLEN);
+       return error;
+}
 
 
-               if (*cp == '\0')
-                       goto emptyname;
+int 
+lookup_validate_creation_path(struct nameidata *ndp)
+{
+       struct componentname *cnp = &ndp->ni_cnd;
 
 
-               /*
-                * cache_lookup_path is now responsible for dropping io ref on dp
-                * when it is called again in the dirloop.  This ensures we hold
-                * a ref on dp until we complete the next round of lookup.
-                */
-               last_dp = dp;
-               goto dirloop;
-       }
-                                 
        /*
        /*
-        * Disallow directory write attempts on read-only file systems.
+        * If creating and at end of pathname, then can consider
+        * allowing file to be created.
         */
         */
-       if (rdonly &&
-           (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
-               error = EROFS;
-               goto bad2;
-       }
-       if (cnp->cn_flags & SAVESTART) {
-               /*      
-                * note that we already hold a reference
-                * on both dp and ni_dvp, but for some reason
-                * can't get another one... in this case we
-                * need to do vnode_put on dp in 'bad2'
-                */
-               if ( (vnode_get(ndp->ni_dvp)) ) {
-                       error = ENOENT;
-                       goto bad2;
-               }
-               ndp->ni_startdir = ndp->ni_dvp;
+       if (cnp->cn_flags & RDONLY) {
+               return EROFS;
        }
        }
-       if (!wantparent && ndp->ni_dvp) {
-               vnode_put(ndp->ni_dvp);
-               ndp->ni_dvp = NULLVP;
+       if ((cnp->cn_flags & ISLASTCN) && (ndp->ni_flag & NAMEI_TRAILINGSLASH) && !(cnp->cn_flags & WILLBEDIR)) {
+               return ENOENT;
        }
        }
+       
+       return 0;
+}
+
+/*
+ * Modifies only ni_vp.  Always returns with ni_vp still valid (iocount held).
+ */
+static int
+lookup_traverse_mountpoints(struct nameidata *ndp, struct componentname *cnp, vnode_t dp, 
+               int vbusyflags, vfs_context_t ctx)
+{
+       mount_t mp;
+       vnode_t tdp;
+       int error = 0;
+       uint32_t depth = 0;
+       vnode_t mounted_on_dp;
+       int current_mount_generation = 0;
+#if CONFIG_TRIGGERS
+       vnode_t triggered_dp = NULLVP;
+       int retry_cnt = 0;
+#define MAX_TRIGGER_RETRIES 1
+#endif
+       
+       if (dp->v_type != VDIR || cnp->cn_flags & NOCROSSMOUNT)
+               return 0;
 
 
-       if (cnp->cn_flags & AUDITVNPATH1)
-               AUDIT_ARG(vnpath, dp, ARG_VNODE1);
-       else if (cnp->cn_flags & AUDITVNPATH2)
-               AUDIT_ARG(vnpath, dp, ARG_VNODE2);
+       mounted_on_dp = dp;
+#if CONFIG_TRIGGERS
+restart:
+#endif
+       current_mount_generation = mount_generation;
 
 
-#if NAMEDRSRCFORK
-       /*
-        * Caller wants the resource fork.
-        */
-       if ((cnp->cn_flags & CN_WANTSRSRCFORK) && (dp != NULLVP)) {
-               vnode_t svp = NULLVP;
-               enum nsoperation nsop;
+       while (dp->v_mountedhere) {
+               vnode_lock_spin(dp);
+               if ((mp = dp->v_mountedhere)) {
+                       mp->mnt_crossref++;
+                       vnode_unlock(dp);
+               } else {
+                       vnode_unlock(dp);
+                       break;
+               }
 
 
-               if (dp->v_type != VREG) {
-                       error = ENOENT;
-                       goto bad2;
+               if (ISSET(mp->mnt_lflag, MNT_LFORCE)) {
+                       mount_dropcrossref(mp, dp, 0);
+                       break;  // don't traverse into a forced unmount
                }
                }
-               switch (cnp->cn_nameiop) {
-               case DELETE:
-                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
-                               nsop = NS_DELETE;
-                       } else {
-                               error = EPERM;
-                               goto bad2;
-                       }
-                       break;
-               case CREATE:
-                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
-                               nsop = NS_CREATE;
-                       } else {
-                               error = EPERM;
-                               goto bad2;
-                       }
-                       break;
-               case LOOKUP:
-                       /* Make sure our lookup of "/..namedfork/rsrc" is allowed. */
-                       if (cnp->cn_flags & CN_ALLOWRSRCFORK) {
-                               nsop = NS_OPEN;
-                       } else {
-                               error = EPERM;
-                               goto bad2;
+
+
+               if (vfs_busy(mp, vbusyflags)) {
+                       mount_dropcrossref(mp, dp, 0);
+                       if (vbusyflags == LK_NOWAIT) {
+                               error = ENOENT;
+                               goto out;
                        }
                        }
-                       break;
-               default:
-                       error = EPERM;
-                       goto bad2;
+
+                       continue;
                }
                }
-               /* Ask the file system for the resource fork. */
-               error = vnode_getnamedstream(dp, &svp, XATTR_RESOURCEFORK_NAME, nsop, 0, ctx);
 
 
-               /* During a create, it OK for stream vnode to be missing. */
-               if (error == ENOATTR || error == ENOENT) {
-                       error = (nsop == NS_CREATE) ? 0 : ENOENT;
-               }               
+               error = VFS_ROOT(mp, &tdp, ctx);
+
+               mount_dropcrossref(mp, dp, 0);
+               vfs_unbusy(mp);
+
                if (error) {
                if (error) {
-                       goto bad2;
-               }
-               /* The "parent" of the stream is the file. */
-               if (wantparent) {
-                       if (ndp->ni_dvp) {
-#ifndef __LP64__
-                               if (ndp->ni_cnd.cn_flags & FSNODELOCKHELD) {
-                                       ndp->ni_cnd.cn_flags &= ~FSNODELOCKHELD;
-                                       unlock_fsnode(ndp->ni_dvp, NULL);
-                               }       
-#endif /* __LP64__ */
-                               vnode_put(ndp->ni_dvp);
-                       }
-                       ndp->ni_dvp = dp;
-               } else {
-                       vnode_put(dp);
+                       goto out;
                }
                }
-               ndp->ni_vp = dp = svp;  /* on create this may be null */
 
 
-               /* Restore the truncated pathname buffer (for audits). */
-               if (ndp->ni_pathlen == 1 && ndp->ni_next[0] == '\0') {
-                       ndp->ni_next[0] = '/';
+               vnode_put(dp);
+               ndp->ni_vp = dp = tdp;
+               if (dp->v_type != VDIR) {
+#if DEVELOPMENT || DEBUG
+                       panic("%s : Root of filesystem not a directory\n",
+                           __FUNCTION__);
+#else
+                       break;
+#endif
                }
                }
-               cnp->cn_flags  &= ~MAKEENTRY;
+               depth++;
        }
        }
-#endif
-       if (kdebug_enable)
-               kdebug_lookup(dp, cnp);
-       return (0);
 
 
-emptyname:
-       cnp->cn_namelen = 0;
+#if CONFIG_TRIGGERS
        /*
        /*
-        * A degenerate name (e.g. / or "") which is a way of
-        * talking about a directory, e.g. like "/." or ".".
+        * The triggered_dp check here is required but is susceptible to a
+        * (unlikely) race in which trigger mount is done from here and is
+        * unmounted before we get past vfs_busy above. We retry to deal with
+        * that case but it has the side effect of unwanted retries for
+        * "special" processes which don't want to trigger mounts.
         */
         */
-       if (dp->v_type != VDIR) {
-               error = ENOTDIR;
-               goto bad;
+       if (dp->v_resolve && retry_cnt < MAX_TRIGGER_RETRIES) {
+               error = vnode_trigger_resolve(dp, ndp, ctx);
+               if (error)
+                       goto out;
+               if (dp == triggered_dp)
+                       retry_cnt += 1;
+               else
+                       retry_cnt = 0;
+               triggered_dp = dp;
+               goto restart;
        }
        }
-       if (cnp->cn_nameiop != LOOKUP) {
-               error = EISDIR;
-               goto bad;
+#endif /* CONFIG_TRIGGERS */
+
+       if (depth) {
+               mp = mounted_on_dp->v_mountedhere;
+
+               if (mp) {
+                       mount_lock_spin(mp);
+                       mp->mnt_realrootvp_vid = dp->v_id;
+                       mp->mnt_realrootvp = dp;
+                       mp->mnt_generation = current_mount_generation;
+                       mount_unlock(mp);
+               }
        }
        }
-       if (wantparent) {
-               /*      
-                * note that we already hold a reference
-                * on dp, but for some reason can't
-                * get another one... in this case we
-                * need to do vnode_put on dp in 'bad'
-                */
-               if ( (vnode_get(dp)) ) {
-                       error = ENOENT;
-                       goto bad;
+
+       return 0;
+
+out:
+       return error;
+}
+
+/*
+ * Takes ni_vp and ni_dvp non-NULL.  Returns with *new_dp set to the location
+ * at which to start a lookup with a resolved path, and all other iocounts dropped.
+ */
+static int 
+lookup_handle_symlink(struct nameidata *ndp, vnode_t *new_dp, vfs_context_t ctx)
+{
+       int error;
+       char *cp;               /* pointer into pathname argument */
+       uio_t auio;
+       union {
+               union {
+                       struct user_iovec s_uiovec;
+                       struct kern_iovec s_kiovec;
+               } u_iovec;
+               struct uio s_uio;
+               char uio_buf[ UIO_SIZEOF(1) ];
+       } u_uio_buf; /* union only for aligning uio_buf correctly */
+       int need_newpathbuf;
+       u_int linklen;
+       struct componentname *cnp = &ndp->ni_cnd;
+       vnode_t dp;
+       char *tmppn;
+
+       if (ndp->ni_loopcnt++ >= MAXSYMLINKS) {
+               return ELOOP;
+       }
+#if CONFIG_MACF
+       if ((error = mac_vnode_check_readlink(ctx, ndp->ni_vp)) != 0)
+               return error;
+#endif /* MAC */
+       if (ndp->ni_pathlen > 1 || !(cnp->cn_flags & HASBUF))
+               need_newpathbuf = 1;
+       else
+               need_newpathbuf = 0;
+
+       if (need_newpathbuf) {
+               MALLOC_ZONE(cp, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
+               if (cp == NULL) {
+                       return ENOMEM;
                }
                }
-               ndp->ni_dvp = dp;
+       } else {
+               cp = cnp->cn_pnbuf;
        }
        }
-       cnp->cn_flags &= ~ISDOTDOT;
-       cnp->cn_flags |= ISLASTCN;
-       ndp->ni_next = cp;
-       ndp->ni_vp = dp;
+       auio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ,
+           &u_uio_buf.uio_buf[0], sizeof(u_uio_buf.uio_buf));
 
 
-       if (cnp->cn_flags & AUDITVNPATH1)
-               AUDIT_ARG(vnpath, dp, ARG_VNODE1);
-       else if (cnp->cn_flags & AUDITVNPATH2)
-               AUDIT_ARG(vnpath, dp, ARG_VNODE2);
-       if (cnp->cn_flags & SAVESTART)
-               panic("lookup: SAVESTART");
-       return (0);
+       uio_addiov(auio, CAST_USER_ADDR_T(cp), MAXPATHLEN);
 
 
-bad2:
-#ifndef __LP64__
-       if ((cnp->cn_flags & FSNODELOCKHELD)) {
-               cnp->cn_flags &= ~FSNODELOCKHELD;
-               unlock_fsnode(ndp->ni_dvp, NULL);
+       error = VNOP_READLINK(ndp->ni_vp, auio, ctx);
+       if (error) {
+               if (need_newpathbuf)
+                       FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
+               return error;
        }
        }
-#endif /* __LP64__ */
-       if (ndp->ni_dvp)
-               vnode_put(ndp->ni_dvp);
-       if (dp)
-               vnode_put(dp);
-       ndp->ni_vp = NULLVP;
 
 
-       if (kdebug_enable)
-               kdebug_lookup(dp, cnp);
-       return (error);
+       /* 
+        * Safe to set unsigned with a [larger] signed type here
+        * because 0 <= uio_resid <= MAXPATHLEN and MAXPATHLEN
+        * is only 1024.
+        */
+       linklen = MAXPATHLEN - (u_int)uio_resid(auio);
+       if (linklen + ndp->ni_pathlen > MAXPATHLEN) {
+               if (need_newpathbuf)
+                       FREE_ZONE(cp, MAXPATHLEN, M_NAMEI);
+
+               return ENAMETOOLONG;
+       }
+       if (need_newpathbuf) {
+               long len = cnp->cn_pnlen;
+
+               tmppn = cnp->cn_pnbuf;
+               bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen);
+               cnp->cn_pnbuf = cp;
+               cnp->cn_pnlen = MAXPATHLEN;
+
+               if ( (cnp->cn_flags & HASBUF) )
+                       FREE_ZONE(tmppn, len, M_NAMEI);
+               else
+                       cnp->cn_flags |= HASBUF;
+       } else
+               cnp->cn_pnbuf[linklen] = '\0';
+
+       ndp->ni_pathlen += linklen;
+       cnp->cn_nameptr = cnp->cn_pnbuf;
+
+       /*
+        * starting point for 'relative'
+        * symbolic link path
+        */
+       dp = ndp->ni_dvp;
+
+       /*
+        * get rid of references returned via 'lookup'
+        */
+       vnode_put(ndp->ni_vp);
+       vnode_put(ndp->ni_dvp); /* ALWAYS have a dvp for a symlink */
 
 
-bad:
-#ifndef __LP64__
-       if ((cnp->cn_flags & FSNODELOCKHELD)) {
-               cnp->cn_flags &= ~FSNODELOCKHELD;
-               unlock_fsnode(ndp->ni_dvp, NULL);
-       }       
-#endif /* __LP64__ */
-       if (dp)
-               vnode_put(dp);
        ndp->ni_vp = NULLVP;
        ndp->ni_vp = NULLVP;
+       ndp->ni_dvp = NULLVP;
 
 
-       if (kdebug_enable)
-               kdebug_lookup(dp, cnp);
-       return (error);
+       /*
+        * Check if symbolic link restarts us at the root
+        */
+       if (*(cnp->cn_nameptr) == '/') {
+               while (*(cnp->cn_nameptr) == '/') {
+                       cnp->cn_nameptr++;
+                       ndp->ni_pathlen--;
+               }
+               if ((dp = ndp->ni_rootdir) == NULLVP) {
+                       return ENOENT;
+               }
+       }
+
+       *new_dp = dp;
+
+       return 0;
 }
 
 /*
 }
 
 /*
@@ -1211,12 +1702,6 @@ bad:
 void
 nameidone(struct nameidata *ndp)
 {
 void
 nameidone(struct nameidata *ndp)
 {
-#ifndef __LP64__
-       if ((ndp->ni_cnd.cn_flags & FSNODELOCKHELD)) {
-               ndp->ni_cnd.cn_flags &= ~FSNODELOCKHELD;
-               unlock_fsnode(ndp->ni_dvp, NULL);
-       }       
-#endif /* __LP64__ */
        if (ndp->ni_cnd.cn_flags & HASBUF) {
                char *tmp = ndp->ni_cnd.cn_pnbuf;
 
        if (ndp->ni_cnd.cn_flags & HASBUF) {
                char *tmp = ndp->ni_cnd.cn_pnbuf;
 
@@ -1227,8 +1712,6 @@ nameidone(struct nameidata *ndp)
 }
 
 
 }
 
 
-#define NUMPARMS 23
-
 /*
  * Log (part of) a pathname using the KERNEL_DEBUG_CONSTANT mechanism, as used
  * by fs_usage.  The path up to and including the current component name are
 /*
  * Log (part of) a pathname using the KERNEL_DEBUG_CONSTANT mechanism, as used
  * by fs_usage.  The path up to and including the current component name are
@@ -1258,11 +1741,64 @@ nameidone(struct nameidata *ndp)
  * fails because /foo_bar_baz is not found will only log "/foo_bar_baz", with
  * no '>' padding.  But /foo_bar/spam would log "/foo_bar>>>>".
  */
  * fails because /foo_bar_baz is not found will only log "/foo_bar_baz", with
  * no '>' padding.  But /foo_bar/spam would log "/foo_bar>>>>".
  */
-static void
-kdebug_lookup(struct vnode *dp, struct componentname *cnp)
+#if (KDEBUG_LEVEL >= KDEBUG_LEVEL_IST)
+
+void
+kdebug_vfs_lookup(long *dbg_parms, int dbg_namelen, void *dp, uint32_t flags)
 {
 {
-       unsigned int i;
        int code;
        int code;
+       unsigned int i;
+       bool lookup = flags & KDBG_VFS_LOOKUP_FLAG_LOOKUP;
+       bool noprocfilt = flags & KDBG_VFS_LOOKUP_FLAG_NOPROCFILT;
+
+       /*
+        * In the event that we collect multiple, consecutive pathname
+        * entries, we must mark the start of the path's string and the end.
+        */
+       if (lookup) {
+               code = VFS_LOOKUP | DBG_FUNC_START;
+       } else {
+               code = VFS_LOOKUP_DONE | DBG_FUNC_START;
+       }
+
+       if (dbg_namelen <= (int)(3 * sizeof(long)))
+               code |= DBG_FUNC_END;
+
+       if (noprocfilt) {
+               KDBG_RELEASE_NOPROCFILT(code, kdebug_vnode(dp), dbg_parms[0],
+                               dbg_parms[1], dbg_parms[2]);
+       } else {
+               KDBG_RELEASE(code, kdebug_vnode(dp), dbg_parms[0], dbg_parms[1],
+                               dbg_parms[2]);
+       }
+
+       code &= ~DBG_FUNC_START;
+
+       for (i=3, dbg_namelen -= (3 * sizeof(long)); dbg_namelen > 0; i+=4, dbg_namelen -= (4 * sizeof(long))) {
+               if (dbg_namelen <= (int)(4 * sizeof(long)))
+                       code |= DBG_FUNC_END;
+
+               if (noprocfilt) {
+                       KDBG_RELEASE_NOPROCFILT(code, dbg_parms[i], dbg_parms[i + 1],
+                                       dbg_parms[i + 2], dbg_parms[i + 3]);
+               } else {
+                       KDBG_RELEASE(code, dbg_parms[i], dbg_parms[i + 1], dbg_parms[i + 2],
+                                       dbg_parms[i + 3]);
+               }
+       }
+}
+
+void
+kdebug_lookup_gen_events(long *dbg_parms, int dbg_namelen, void *dp,
+               boolean_t lookup)
+{
+       kdebug_vfs_lookup(dbg_parms, dbg_namelen, dp,
+                       lookup ? KDBG_VFS_LOOKUP_FLAG_LOOKUP : 0);
+}
+
+void
+kdebug_lookup(vnode_t dp, struct componentname *cnp)
+{
        int dbg_namelen;
        char *dbg_nameptr;
        long dbg_parms[NUMPARMS];
        int dbg_namelen;
        char *dbg_nameptr;
        long dbg_parms[NUMPARMS];
@@ -1284,28 +1820,45 @@ kdebug_lookup(struct vnode *dp, struct componentname *cnp)
                       *(cnp->cn_nameptr + cnp->cn_namelen) ? '>' : 0,
                       sizeof(dbg_parms) - dbg_namelen);
        }
                       *(cnp->cn_nameptr + cnp->cn_namelen) ? '>' : 0,
                       sizeof(dbg_parms) - dbg_namelen);
        }
-       
-       /*
-        * In the event that we collect multiple, consecutive pathname
-        * entries, we must mark the start of the path's string and the end.
-        */
-       code = (FSDBG_CODE(DBG_FSRW,36)) | DBG_FUNC_START;
+       kdebug_vfs_lookup(dbg_parms, dbg_namelen, (void *)dp,
+                       KDBG_VFS_LOOKUP_FLAG_LOOKUP);
+}
 
 
-       if (dbg_namelen <= 12)
-               code |= DBG_FUNC_END;
+#else /* (KDEBUG_LEVEL >= KDEBUG_LEVEL_IST) */
 
 
-       KERNEL_DEBUG_CONSTANT(code, dp, dbg_parms[0], dbg_parms[1], dbg_parms[2], 0);
+void
+kdebug_vfs_lookup(long *dbg_parms __unused, int dbg_namelen __unused,
+               void *dp __unused, __unused uint32_t flags)
+{
+}
 
 
-       code &= ~DBG_FUNC_START;
+static void
+kdebug_lookup(struct vnode *dp __unused, struct componentname *cnp __unused)
+{
+}
+#endif /* (KDEBUG_LEVEL >= KDEBUG_LEVEL_IST) */
 
 
-       for (i=3, dbg_namelen -= 12; dbg_namelen > 0; i+=4, dbg_namelen -= 16) {
-               if (dbg_namelen <= 16)
-                       code |= DBG_FUNC_END;
+int
+vfs_getbyid(fsid_t *fsid, ino64_t ino, vnode_t *vpp, vfs_context_t ctx)
+{
+       mount_t mp;
+       int error;
+       
+       mp = mount_lookupby_volfsid(fsid->val[0], 1);
+       if (mp == NULL) {
+               return EINVAL;
+       }
 
 
-               KERNEL_DEBUG_CONSTANT(code, dbg_parms[i], dbg_parms[i+1], dbg_parms[i+2], dbg_parms[i+3], 0);
+       /* Get the target vnode. */
+       if (ino == 2) {
+               error = VFS_ROOT(mp, vpp, ctx);
+       } else {
+               error = VFS_VGET(mp, ino, vpp, ctx);
        }
        }
-}
 
 
+       vfs_unbusy(mp);
+       return error;
+}
 /*
  * Obtain the real path from a legacy volfs style path.
  *
 /*
  * Obtain the real path from a legacy volfs style path.
  *
@@ -1384,3 +1937,59 @@ out:
        return (error);
 }
 #endif
        return (error);
 }
 #endif
+
+void
+lookup_compound_vnop_post_hook(int error, vnode_t dvp, vnode_t vp, struct nameidata *ndp, int did_create)
+{
+       if (error == 0 && vp == NULLVP) {
+               panic("NULL vp with error == 0.\n");
+       }
+
+       /* 
+        * We don't want to do any of this if we didn't use the compound vnop
+        * to perform the lookup... i.e. if we're allowing and using the legacy pattern,
+        * where we did a full lookup.
+        */
+       if ((ndp->ni_flag & NAMEI_COMPOUND_OP_MASK) == 0) {
+               return;
+       }
+
+       /* 
+        * If we're going to continue the lookup, we'll handle
+        * all lookup-related updates at that time.
+        */
+       if (error == EKEEPLOOKING) {
+               return;
+       }
+
+       /*
+        * Only audit or update cache for *found* vnodes.  For creation
+        * neither would happen in the non-compound-vnop case.
+        */
+       if ((vp != NULLVP) && !did_create) {
+               /* 
+                * If MAKEENTRY isn't set, and we've done a successful compound VNOP, 
+                * then we certainly don't want to update cache or identity.
+                */
+               if ((error != 0) || (ndp->ni_cnd.cn_flags & MAKEENTRY)) {
+                       lookup_consider_update_cache(dvp, vp, &ndp->ni_cnd, ndp->ni_ncgeneration);
+               }
+               if (ndp->ni_cnd.cn_flags & AUDITVNPATH1)
+                       AUDIT_ARG(vnpath, vp, ARG_VNODE1);
+               else if (ndp->ni_cnd.cn_flags & AUDITVNPATH2)
+                       AUDIT_ARG(vnpath, vp, ARG_VNODE2);
+       }
+
+       /* 
+        * If you created (whether you opened or not), cut a lookup tracepoint 
+        * for the parent dir (as would happen without a compound vnop).  Note: we may need
+        * a vnode despite failure in this case!
+        *
+        * If you did not create:
+        *      Found child (succeeded or not): cut a tracepoint for the child.  
+        *      Did not find child: cut a tracepoint with the parent.
+        */
+       if (kdebug_enable) {
+               kdebug_lookup(vp ? vp : dvp, &ndp->ni_cnd); 
+       }
+}
mirror of XNU