bsd/hfs/hfs_link.c

   1 /*
   2  * Copyright (c) 1999-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25
  26
  27 #include <sys/systm.h>
  28 #include <sys/kernel.h>
  29 #include <sys/malloc.h>
  30 #include <sys/mount.h>
  31 #include <sys/namei.h>
  32 #include <sys/stat.h>
  33 #include <sys/vnode.h>
  34 #include <vfs/vfs_support.h>
  35 #include <libkern/libkern.h>
  36
  37 #include "hfs.h"
  38 #include "hfs_catalog.h"
  39 #include "hfs_format.h"
  40 #include "hfs_endian.h"
  41
  42
  43 /*
  44  * Create a new indirect link
  45  *
  46  * An indirect link is a reference to a data node.  The only useable
  47  * fields in the link are the link number, parentID, name and text
  48  * encoding.  All other catalog fields are ignored.
  49  */
  50 static int
  51 createindirectlink(struct hfsmount *hfsmp, u_int32_t linknum,
  52                         u_int32_t linkparid, char *linkName, cnid_t *linkcnid)
  53 {
  54         struct FndrFileInfo *fip;
  55         struct cat_desc desc;
  56         struct cat_attr attr;
  57         int result;
  58
  59         /* Setup the descriptor */
  60         bzero(&desc, sizeof(desc));
  61         desc.cd_nameptr = linkName;
  62         desc.cd_namelen = strlen(linkName);
  63         desc.cd_parentcnid = linkparid;
  64
  65         /* Setup the default attributes */
  66         bzero(&attr, sizeof(attr));
  67
  68         /* links are matched to data nodes by link ID and to volumes by create date */
  69         attr.ca_rdev = linknum;  /* note: cat backend overloads ca_rdev to be the linknum when nlink = 0 */
  70         attr.ca_itime = HFSTOVCB(hfsmp)->vcbCrDate;
  71         attr.ca_mode = S_IFREG;
  72
  73         fip = (struct FndrFileInfo *)&attr.ca_finderinfo;
  74         fip->fdType    = SWAP_BE32 (kHardLinkFileType); /* 'hlnk' */
  75         fip->fdCreator = SWAP_BE32 (kHFSPlusCreator);   /* 'hfs+' */
  76         fip->fdFlags   = SWAP_BE16 (kHasBeenInited);
  77
  78         hfs_global_shared_lock_acquire(hfsmp);
  79         if (hfsmp->jnl) {
  80             if (journal_start_transaction(hfsmp->jnl) != 0) {
  81                         hfs_global_shared_lock_release(hfsmp);
  82                         return EINVAL;
  83             }
  84         }
  85
  86         /* Create the indirect link directly in the catalog */
  87         result = cat_create(hfsmp, &desc, &attr, NULL);
  88
  89         if (result == 0 && linkcnid != NULL)
  90                 *linkcnid = attr.ca_fileid;
  91
  92         if (hfsmp->jnl) {
  93             journal_end_transaction(hfsmp->jnl);
  94         }
  95         hfs_global_shared_lock_release(hfsmp);
  96
  97         return (result);
  98 }
  99
 100
 101 /*
 102  * 2 locks are needed (dvp and vp)
 103  * also need catalog lock
 104  *
 105  * caller's responsibility:
 106  *              componentname cleanup
 107  *              unlocking dvp and vp
 108  */
 109 static int
 110 hfs_makelink(struct hfsmount *hfsmp, struct cnode *cp, struct cnode *dcp,
 111                 struct componentname *cnp)
 112 {
 113         struct proc *p = cnp->cn_proc;
 114         u_int32_t indnodeno = 0;
 115         char inodename[32];
 116         struct cat_desc to_desc;
 117         int newlink = 0;
 118         int retval;
 119
 120
 121         /* We don't allow link nodes in our Private Meta Data folder! */
 122         if (dcp->c_fileid == hfsmp->hfs_privdir_desc.cd_cnid)
 123                 return (EPERM);
 124
 125         if (hfs_freeblks(hfsmp, 0) == 0)
 126                 return (ENOSPC);
 127
 128         /* Lock catalog b-tree */
 129         retval = hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_EXCLUSIVE, p);
 130         if (retval) {
 131             return retval;
 132         }
 133
 134         /*
 135          * If this is a new hardlink then we need to create the data
 136          * node (inode) and replace the original file with a link node.
 137          */
 138         if (cp->c_nlink == 2 && (cp->c_flag & C_HARDLINK) == 0) {
 139                 newlink = 1;
 140                 bzero(&to_desc, sizeof(to_desc));
 141                 to_desc.cd_parentcnid = hfsmp->hfs_privdir_desc.cd_cnid;
 142                 to_desc.cd_cnid = cp->c_fileid;
 143
 144                 do {
 145                         /* get a unique indirect node number */
 146                         indnodeno = ((random() & 0x3fffffff) + 100);
 147                         MAKE_INODE_NAME(inodename, indnodeno);
 148
 149                         /* move source file to data node directory */
 150                         to_desc.cd_nameptr = inodename;
 151                         to_desc.cd_namelen = strlen(inodename);
 152
 153                         retval = cat_rename(hfsmp, &cp->c_desc, &hfsmp->hfs_privdir_desc,
 154                                         &to_desc, NULL);
 155
 156                 } while (retval == EEXIST);
 157                 if (retval)
 158                         goto out;
 159
 160                 /* Replace source file with link node */
 161                 retval = createindirectlink(hfsmp, indnodeno, cp->c_parentcnid,
 162                                 cp->c_desc.cd_nameptr, &cp->c_desc.cd_cnid);
 163                 if (retval) {
 164                         /* put it source file back */
 165                 // XXXdbg
 166                 #if 1
 167                     {
 168                         int err;
 169                                 err = cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
 170                                 if (err)
 171                                         panic("hfs_makelink: error %d from cat_rename backout 1", err);
 172                     }
 173                 #else
 174                         (void) cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
 175                 #endif
 176                         goto out;
 177                 }
 178                 cp->c_rdev = indnodeno;
 179         } else {
 180                 indnodeno = cp->c_rdev;
 181         }
 182
 183         /*
 184          * Create a catalog entry for the new link (parentID + name).
 185          */
 186         retval = createindirectlink(hfsmp, indnodeno, dcp->c_fileid, cnp->cn_nameptr, NULL);
 187         if (retval && newlink) {
 188                 /* Get rid of new link */
 189                 (void) cat_delete(hfsmp, &cp->c_desc, &cp->c_attr);
 190
 191                 /* Put the source file back */
 192         // XXXdbg
 193         #if 1
 194                 {
 195                         int err;
 196                         err = cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
 197                         if (err)
 198                                 panic("hfs_makelink: error %d from cat_rename backout 2", err);
 199                 }
 200         #else
 201                 (void) cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
 202         #endif
 203                 goto out;
 204         }
 205
 206         /*
 207          * Finally, if this is a new hardlink then:
 208          *  - update HFS Private Data dir
 209          *  - mark the cnode as a hard link
 210          */
 211         if (newlink) {
 212                 hfsmp->hfs_privdir_attr.ca_entries++;
 213                 (void)cat_update(hfsmp, &hfsmp->hfs_privdir_desc,
 214                         &hfsmp->hfs_privdir_attr, NULL, NULL);
 215                 hfs_volupdate(hfsmp, VOL_MKFILE, 0);
 216                 cp->c_flag |= (C_CHANGE | C_HARDLINK);
 217         }
 218
 219 out:
 220         /* Unlock catalog b-tree */
 221         (void) hfs_metafilelocking(hfsmp, kHFSCatalogFileID, LK_RELEASE, p);
 222
 223         return (retval);
 224 }
 225
 226
 227 /*
 228  * link vnode call
 229 #% link         vp      U U U
 230 #% link         tdvp    L U U
 231 #
 232  vop_link {
 233      IN WILLRELE struct vnode *vp;
 234      IN struct vnode *targetPar_vp;
 235      IN struct componentname *cnp;
 236
 237      */
 238 int
 239 hfs_link(ap)
 240         struct vop_link_args /* {
 241                 struct vnode *a_vp;
 242                 struct vnode *a_tdvp;
 243                 struct componentname *a_cnp;
 244         } */ *ap;
 245 {
 246         struct hfsmount *hfsmp;
 247         struct vnode *vp = ap->a_vp;
 248         struct vnode *tdvp = ap->a_tdvp;
 249         struct componentname *cnp = ap->a_cnp;
 250         struct proc *p = cnp->cn_proc;
 251         struct cnode *cp;
 252         struct cnode *tdcp;
 253         struct timeval tv;
 254         int error;
 255
 256         hfsmp = VTOHFS(vp);
 257
 258 #if HFS_DIAGNOSTIC
 259         if ((cnp->cn_flags & HASBUF) == 0)
 260                 panic("hfs_link: no name");
 261 #endif
 262         if (tdvp->v_mount != vp->v_mount) {
 263                 VOP_ABORTOP(tdvp, cnp);
 264                 error = EXDEV;
 265                 goto out2;
 266         }
 267         if (VTOVCB(tdvp)->vcbSigWord != kHFSPlusSigWord)
 268                 return err_link(ap);    /* hfs disks don't support hard links */
 269
 270         if (hfsmp->hfs_private_metadata_dir == 0)
 271                 return err_link(ap);    /* no private metadata dir, no links possible */
 272
 273         if (tdvp != vp && (error = vn_lock(vp, LK_EXCLUSIVE, p))) {
 274                 VOP_ABORTOP(tdvp, cnp);
 275                 goto out2;
 276         }
 277         cp = VTOC(vp);
 278         tdcp = VTOC(tdvp);
 279
 280         if (cp->c_nlink >= HFS_LINK_MAX) {
 281                 VOP_ABORTOP(tdvp, cnp);
 282                 error = EMLINK;
 283                 goto out1;
 284         }
 285         if (cp->c_flags & (IMMUTABLE | APPEND)) {
 286                 VOP_ABORTOP(tdvp, cnp);
 287                 error = EPERM;
 288                 goto out1;
 289         }
 290         if (vp->v_type == VBLK || vp->v_type == VCHR) {
 291                 VOP_ABORTOP(tdvp, cnp);
 292                 error = EINVAL;  /* cannot link to a special file */
 293                 goto out1;
 294         }
 295
 296         hfs_global_shared_lock_acquire(hfsmp);
 297         if (hfsmp->jnl) {
 298             if (journal_start_transaction(hfsmp->jnl) != 0) {
 299                         hfs_global_shared_lock_release(hfsmp);
 300                         VOP_ABORTOP(tdvp, cnp);
 301                         error = EINVAL;  /* cannot link to a special file */
 302                         goto out1;
 303             }
 304         }
 305
 306         cp->c_nlink++;
 307         cp->c_flag |= C_CHANGE;
 308         tv = time;
 309
 310         error = VOP_UPDATE(vp, &tv, &tv, 1);
 311         if (!error) {
 312                 error = hfs_makelink(hfsmp, cp, tdcp, cnp);
 313         }
 314         if (error) {
 315                 cp->c_nlink--;
 316                 cp->c_flag |= C_CHANGE;
 317         } else {
 318                 /* Update the target directory and volume stats */
 319                 tdcp->c_nlink++;
 320                 tdcp->c_entries++;
 321                 tdcp->c_flag |= C_CHANGE | C_UPDATE;
 322                 tv = time;
 323                 (void) VOP_UPDATE(tdvp, &tv, &tv, 0);
 324
 325                 hfs_volupdate(hfsmp, VOL_MKFILE,
 326                         (tdcp->c_cnid == kHFSRootFolderID));
 327         }
 328
 329         // XXXdbg - need to do this here as well because cp could have changed
 330         error = VOP_UPDATE(vp, &tv, &tv, 1);
 331
 332         FREE_ZONE(cnp->cn_pnbuf, cnp->cn_pnlen, M_NAMEI);
 333
 334         if (hfsmp->jnl) {
 335             journal_end_transaction(hfsmp->jnl);
 336         }
 337         hfs_global_shared_lock_release(hfsmp);
 338
 339 out1:
 340         if (tdvp != vp)
 341                 VOP_UNLOCK(vp, 0, p);
 342 out2:
 343         vput(tdvp);
 344         return (error);
 345 }