xnu-2050.48.11.tar.gz

[apple/xnu.git] / bsd / hfs / hfs_vnops.c

diff --git a/bsd/hfs/hfs_vnops.c b/bsd/hfs/hfs_vnops.c
index e48966c3cc28640e3dc375a8844e719a54fc3718..fad99d0a4fe1afaf63ff5df22ae7e38fdc964c40 100644 (file)
--- a/bsd/hfs/hfs_vnops.c
+++ b/bsd/hfs/hfs_vnops.c
@@ -1,5 +1,5 @@
 /*
 /*

- * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2013 Apple Inc. All rights reserved.

  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 


@@ -1618,7 +1618,8 @@ hfs_vnop_exchange(ap)
        const unsigned char *to_nameptr;
        char from_iname[32];
        char to_iname[32];
        const unsigned char *to_nameptr;
        char from_iname[32];
        char to_iname[32];

-       u_int32_t tempflag;
+       uint32_t to_flag_special;
+       uint32_t from_flag_special;

        cnid_t  from_parid;
        cnid_t  to_parid;
        int lockflags;
        cnid_t  from_parid;
        cnid_t  to_parid;
        int lockflags;


@@ -1711,9 +1712,8 @@ hfs_vnop_exchange(ap)
        to_cp = VTOC(to_vp);
        hfsmp = VTOHFS(from_vp);
 
        to_cp = VTOC(to_vp);
        hfsmp = VTOHFS(from_vp);
 

-       /* Only normal files can be exchanged. */
-       if (!vnode_isreg(from_vp) || !vnode_isreg(to_vp) ||
-           VNODE_IS_RSRC(from_vp) || VNODE_IS_RSRC(to_vp)) {
+       /* Resource forks cannot be exchanged. */
+       if (VNODE_IS_RSRC(from_vp) || VNODE_IS_RSRC(to_vp)) {

                error = EINVAL;
                goto exit;
        }
                error = EINVAL;
                goto exit;
        }


@@ -1800,7 +1800,14 @@ hfs_vnop_exchange(ap)
        /* Save a copy of from attributes before swapping. */
        bcopy(&from_cp->c_desc, &tempdesc, sizeof(struct cat_desc));
        bcopy(&from_cp->c_attr, &tempattr, sizeof(struct cat_attr));
        /* Save a copy of from attributes before swapping. */
        bcopy(&from_cp->c_desc, &tempdesc, sizeof(struct cat_desc));
        bcopy(&from_cp->c_attr, &tempattr, sizeof(struct cat_attr));

-       tempflag = from_cp->c_flag & (C_HARDLINK | C_HASXATTRS);
+       
+       /* Save whether or not each cnode is a hardlink or has EAs */
+       from_flag_special = from_cp->c_flag & (C_HARDLINK | C_HASXATTRS);
+       to_flag_special = to_cp->c_flag & (C_HARDLINK | C_HASXATTRS);
+
+       /* Drop the special bits from each cnode */
+       from_cp->c_flag &= ~(C_HARDLINK | C_HASXATTRS);
+       to_cp->c_flag &= ~(C_HARDLINK | C_HASXATTRS);

 
        /*
         * Swap the descriptors and all non-fork related attributes.
 
        /*
         * Swap the descriptors and all non-fork related attributes.


@@ -1809,7 +1816,16 @@ hfs_vnop_exchange(ap)
        bcopy(&to_cp->c_desc, &from_cp->c_desc, sizeof(struct cat_desc));
 
        from_cp->c_hint = 0;
        bcopy(&to_cp->c_desc, &from_cp->c_desc, sizeof(struct cat_desc));
 
        from_cp->c_hint = 0;

-       from_cp->c_fileid = from_cp->c_cnid;
+       /*
+        * If 'to' was a hardlink, then we copied over its link ID/CNID/(namespace ID) 
+        * when we bcopy'd the descriptor above.  However, we need to be careful
+        * when setting up the fileID below, because we cannot assume that the
+        * file ID is the same as the CNID if either one was a hardlink.  
+        * The file ID is stored in the c_attr as the ca_fileid. So it needs 
+        * to be pulled explicitly; we cannot just use the CNID.
+        */ 
+       from_cp->c_fileid = to_cp->c_attr.ca_fileid;
+       

        from_cp->c_itime = to_cp->c_itime;
        from_cp->c_btime = to_cp->c_btime;
        from_cp->c_atime = to_cp->c_atime;
        from_cp->c_itime = to_cp->c_itime;
        from_cp->c_btime = to_cp->c_btime;
        from_cp->c_atime = to_cp->c_atime;


@@ -1819,13 +1835,42 @@ hfs_vnop_exchange(ap)
        from_cp->c_bsdflags = to_cp->c_bsdflags;
        from_cp->c_mode = to_cp->c_mode;
        from_cp->c_linkcount = to_cp->c_linkcount;
        from_cp->c_bsdflags = to_cp->c_bsdflags;
        from_cp->c_mode = to_cp->c_mode;
        from_cp->c_linkcount = to_cp->c_linkcount;

-       from_cp->c_flag = to_cp->c_flag & (C_HARDLINK | C_HASXATTRS);
+       from_cp->c_attr.ca_linkref = to_cp->c_attr.ca_linkref;
+       from_cp->c_attr.ca_firstlink = to_cp->c_attr.ca_firstlink;
+
+       /* 
+        * The cnode flags need to stay with the cnode and not get transferred
+        * over along with everything else because they describe the content; they are
+        * not attributes that reflect changes specific to the file ID.  In general, 
+        * fields that are tied to the file ID are the ones that will move.
+        * 
+        * This reflects the fact that the file may have borrowed blocks, dirty metadata, 
+        * or other extents, which may not yet have been written to the catalog.  If 
+        * they were, they would have been transferred above in the ExchangeFileIDs call above...
+        *
+        * The flags that are special are:
+        * C_HARDLINK, C_HASXATTRS
+        * 
+        * These flags move with the item and file ID in the namespace since their
+        * state is tied to that of the file ID.
+        * 
+        * So to transfer the flags, we have to take the following steps
+        * 1) Store in a localvar whether or not the special bits are set.
+        * 2) Drop the special bits from the current flags
+        * 3) swap the special flag bits to their destination
+        */      
+       from_cp->c_flag |= to_flag_special;
+       

        from_cp->c_attr.ca_recflags = to_cp->c_attr.ca_recflags;
        bcopy(to_cp->c_finderinfo, from_cp->c_finderinfo, 32);
 
        bcopy(&tempdesc, &to_cp->c_desc, sizeof(struct cat_desc));
        to_cp->c_hint = 0;
        from_cp->c_attr.ca_recflags = to_cp->c_attr.ca_recflags;
        bcopy(to_cp->c_finderinfo, from_cp->c_finderinfo, 32);
 
        bcopy(&tempdesc, &to_cp->c_desc, sizeof(struct cat_desc));
        to_cp->c_hint = 0;

-       to_cp->c_fileid = to_cp->c_cnid;
+       /* 
+        * Pull the file ID from the tempattr we copied above. We can't assume 
+        * it is the same as the CNID.
+        */
+       to_cp->c_fileid = tempattr.ca_fileid;

        to_cp->c_itime = tempattr.ca_itime;
        to_cp->c_btime = tempattr.ca_btime;
        to_cp->c_atime = tempattr.ca_atime;
        to_cp->c_itime = tempattr.ca_itime;
        to_cp->c_btime = tempattr.ca_btime;
        to_cp->c_atime = tempattr.ca_atime;


@@ -1835,7 +1880,15 @@ hfs_vnop_exchange(ap)
        to_cp->c_bsdflags = tempattr.ca_flags;
        to_cp->c_mode = tempattr.ca_mode;
        to_cp->c_linkcount = tempattr.ca_linkcount;
        to_cp->c_bsdflags = tempattr.ca_flags;
        to_cp->c_mode = tempattr.ca_mode;
        to_cp->c_linkcount = tempattr.ca_linkcount;

-       to_cp->c_flag = tempflag;
+       to_cp->c_attr.ca_linkref = tempattr.ca_linkref;
+       to_cp->c_attr.ca_firstlink = tempattr.ca_firstlink;
+
+       /* 
+        * Only OR in the "from" flags into our cnode flags below. 
+        * Leave the rest of the flags alone.
+        */
+       to_cp->c_flag |= from_flag_special;
+

        to_cp->c_attr.ca_recflags = tempattr.ca_recflags;
        bcopy(tempattr.ca_finderinfo, to_cp->c_finderinfo, 32);
 
        to_cp->c_attr.ca_recflags = tempattr.ca_recflags;
        bcopy(tempattr.ca_finderinfo, to_cp->c_finderinfo, 32);
 


@@ -4167,6 +4220,41 @@ skip_rm:
 
        tdcp->c_flag |= C_FORCEUPDATE;  // XXXdbg - force it out!
        (void) hfs_update(tdvp, 0);
 
        tdcp->c_flag |= C_FORCEUPDATE;  // XXXdbg - force it out!
        (void) hfs_update(tdvp, 0);

+
+       /* Update the vnode's name now that the rename has completed. */
+       vnode_update_identity(fvp, tdvp, tcnp->cn_nameptr, tcnp->cn_namelen, 
+                       tcnp->cn_hash, (VNODE_UPDATE_PARENT | VNODE_UPDATE_NAME));
+
+       /* 
+        * At this point, we may have a resource fork vnode attached to the 
+        * 'from' vnode.  If it exists, we will want to update its name, because
+        * it contains the old name + _PATH_RSRCFORKSPEC. ("/..namedfork/rsrc").
+        *
+        * Note that the only thing we need to update here is the name attached to
+        * the vnode, since a resource fork vnode does not have a separate resource
+        * cnode -- it's still 'fcp'.
+        */
+       if (fcp->c_rsrc_vp) {
+               char* rsrc_path = NULL;
+               int len;
+
+               /* Create a new temporary buffer that's going to hold the new name */
+               MALLOC_ZONE (rsrc_path, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+               len = snprintf (rsrc_path, MAXPATHLEN, "%s%s", tcnp->cn_nameptr, _PATH_RSRCFORKSPEC);
+               len = MIN(len, MAXPATHLEN);
+
+               /* 
+                * vnode_update_identity will do the following for us:
+                * 1) release reference on the existing rsrc vnode's name.
+                * 2) copy/insert new name into the name cache
+                * 3) attach the new name to the resource vnode
+                * 4) update the vnode's vid
+                */
+               vnode_update_identity (fcp->c_rsrc_vp, fvp, rsrc_path, len, 0, (VNODE_UPDATE_NAME | VNODE_UPDATE_CACHE));
+
+               /* Free the memory associated with the resource fork's name */
+               FREE_ZONE (rsrc_path, MAXPATHLEN, M_NAMEI);     
+       }

 out:
        if (got_cookie) {
                cat_postflight(hfsmp, &cookie, p);
 out:
        if (got_cookie) {
                cat_postflight(hfsmp, &cookie, p);


@@ -5516,14 +5604,61 @@ restart:
 
                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
 
 
                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
 

-               /* Get resource fork data */
-               error = cat_lookup(hfsmp, descptr, 1, (struct cat_desc *)0,
-                               (struct cat_attr *)0, &rsrcfork, NULL);
+               /* 
+                * Get resource fork data
+                *
+                * We call cat_idlookup (instead of cat_lookup) below because we can't
+                * trust the descriptor in the provided cnode for lookups at this point.  
+                * Between the time of the original lookup of this vnode and now, the 
+                * descriptor could have gotten swapped or replaced.  If this occurred, 
+                * the parent/name combo originally desired may not necessarily be provided
+                * if we use the descriptor.  Even worse, if the vnode represents
+                * a hardlink, we could have removed one of the links from the namespace
+                * but left the descriptor alone, since hfs_unlink does not invalidate
+                * the descriptor in the cnode if other links still point to the inode.
+                * 
+                * Consider the following (slightly contrived) scenario:
+                * /tmp/a <--> /tmp/b (hardlinks).
+                * 1. Thread A: open rsrc fork on /tmp/b.
+                * 1a. Thread A: does lookup, goes out to lunch right before calling getnamedstream.
+                * 2. Thread B does 'mv /foo/b /tmp/b'
+                * 2. Thread B succeeds.
+                * 3. Thread A comes back and wants rsrc fork info for /tmp/b.  
+                * 
+                * Even though the hardlink backing /tmp/b is now eliminated, the descriptor
+                * is not removed/updated during the unlink process.  So, if you were to
+                * do a lookup on /tmp/b, you'd acquire an entirely different record's resource
+                * fork.
+                * 
+                * As a result, we use the fileid, which should be invariant for the lifetime
+                * of the cnode (possibly barring calls to exchangedata).
+                *
+                * Addendum: We can't do the above for HFS standard since we aren't guaranteed to
+                * have thread records for files.  They were only required for directories.  So
+                * we need to do the lookup with the catalog name. This is OK since hardlinks were
+                * never allowed on HFS standard.
+                */
+
+               if (hfsmp->hfs_flags & HFS_STANDARD) {
+                       /* 
+                        * HFS standard only:
+                        * 
+                        * Get the resource fork for this item via catalog lookup
+                        * since HFS standard was case-insensitive only. We don't want the 
+                        * descriptor; just the fork data here.
+                        */
+                       error = cat_lookup (hfsmp, descptr, 1, (struct cat_desc*)NULL, 
+                                       (struct cat_attr*)NULL, &rsrcfork, NULL);
+               }
+               else {
+                       error = cat_idlookup (hfsmp, cp->c_fileid, 0, 1, NULL, NULL, &rsrcfork);
+               }

 
                hfs_systemfile_unlock(hfsmp, lockflags);
                if (error) {
                        return (error);
                }
 
                hfs_systemfile_unlock(hfsmp, lockflags);
                if (error) {
                        return (error);
                }

+

                /*
                 * Supply hfs_getnewvnode with a component name. 
                 */
                /*
                 * Supply hfs_getnewvnode with a component name. 
                 */