/* * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* $NetBSD: cd9660_lookup.c,v 1.13 1994/12/24 15:30:03 cgd Exp $ */ /*- * Copyright (c) 1989, 1993, 1994 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension * Support code is derived from software contributed to Berkeley * by Atsushi Murai (amurai@spec.co.jp). * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 * * @(#)cd9660_lookup.c 8.5 (Berkeley) 12/5/94 * */ #include <sys/param.h> #include <sys/vnode.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/buf.h> #include <sys/file.h> #include <sys/utfconv.h> #include <isofs/cd9660/iso.h> #include <isofs/cd9660/cd9660_node.h> #include <isofs/cd9660/iso_rrip.h> #include <isofs/cd9660/cd9660_rrip.h> struct nchstats iso_nchstats; /* * Convert a component of a pathname into a pointer to a locked inode. * This is a very central and rather complicated routine. * If the file system is not maintained in a strict tree hierarchy, * this can result in a deadlock situation (see comments in code below). * * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on * whether the name is to be looked up, created, renamed, or deleted. * When CREATE, RENAME, or DELETE is specified, information usable in * creating, renaming, or deleting a directory entry may be calculated. * If flag has LOCKPARENT or'ed into it and the target of the pathname * exists, lookup returns both the target and its parent directory locked. * When creating or renaming and LOCKPARENT is specified, the target may * not be ".". When deleting and LOCKPARENT is specified, the target may * be "."., but the caller must check to ensure it does an vrele and iput * instead of two iputs. * * Overall outline of ufs_lookup: * * check accessibility of directory * look for name in cache, if found, then if at end of path * and deleting or creating, drop it, else return name * search for name in directory, to found or notfound * notfound: * if creating, return locked directory, leaving info on available slots * else return error * found: * if at end of path and deleting, return information to allow delete * if at end of path and rewriting (RENAME and LOCKPARENT), lock target * inode and return info to allow rewrite * if not at end, add name to cache; if at end and neither creating * nor deleting, add name to cache * * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. */ int cd9660_lookup(ap) struct vop_lookup_args /* { struct vnode *a_dvp; struct vnode **a_vpp; struct componentname *a_cnp; } */ *ap; { register struct vnode *vdp; /* vnode for directory being searched */ register struct iso_node *dp; /* inode for directory being searched */ register struct iso_mnt *imp; /* file system that directory is in */ struct buf *bp; /* a buffer of directory entries */ struct iso_directory_record *ep = NULL;/* the current directory entry */ int entryoffsetinblock; /* offset of ep in bp's buffer */ int saveoffset = 0; /* offset of last directory entry in dir */ int numdirpasses; /* strategy for directory search */ doff_t endsearch; /* offset to end directory search */ struct vnode *pdp; /* saved dp during symlink work */ struct vnode *tdp; /* returned by cd9660_vget_internal */ u_long bmask; /* block offset mask */ int lockparent; /* 1 => lockparent flag is set */ int wantparent; /* 1 => wantparent or lockparent flag */ int wantassoc; int error; ino_t ino = 0; int reclen; u_short namelen; int isoflags; char altname[ISO_RRIP_NAMEMAX]; int res; int len; char *name; struct vnode **vpp = ap->a_vpp; struct componentname *cnp = ap->a_cnp; int flags = cnp->cn_flags; int nameiop = cnp->cn_nameiop; struct proc *p = cnp->cn_proc; int devBlockSize=0; size_t altlen; bp = NULL; *vpp = NULL; vdp = ap->a_dvp; dp = VTOI(vdp); imp = dp->i_mnt; lockparent = flags & LOCKPARENT; wantparent = flags & (LOCKPARENT|WANTPARENT); wantassoc = 0; /* * Check accessiblity of directory. */ if (vdp->v_type != VDIR) return (ENOTDIR); if ( (error = VOP_ACCESS(vdp, VEXEC, cnp->cn_cred, p)) ) return (error); /* * We now have a segment name to search for, and a directory to search. * * Before tediously performing a linear scan of the directory, * check the name cache to see if the directory/name pair * we are looking for is known already. */ if ((error = cache_lookup(vdp, vpp, cnp))) { int vpid; /* capability number of vnode */ if (error == ENOENT) return (error); /* * Get the next vnode in the path. * See comment below starting `Step through' for * an explaination of the locking protocol. */ pdp = vdp; dp = VTOI(*vpp); vdp = *vpp; vpid = vdp->v_id; if (pdp == vdp) { VREF(vdp); error = 0; } else if (flags & ISDOTDOT) { VOP_UNLOCK(pdp, 0, p); error = vget(vdp, LK_EXCLUSIVE | LK_RETRY, p); if (!error && lockparent && (flags & ISLASTCN)) error = VOP_LOCK(pdp, LK_EXCLUSIVE | LK_RETRY, p); } else { error = vget(vdp, LK_EXCLUSIVE | LK_RETRY, p); if (!lockparent || error || !(flags & ISLASTCN)) VOP_UNLOCK(pdp, 0, p); } /* * Check that the capability number did not change * while we were waiting for the lock. */ if (!error) { if (vpid == vdp->v_id) return (0); vput(vdp); if (lockparent && pdp != vdp && (flags & ISLASTCN)) VOP_UNLOCK(pdp, 0, p); } if ( (error = VOP_LOCK(pdp, LK_EXCLUSIVE | LK_RETRY, p)) ) return (error); vdp = pdp; dp = VTOI(pdp); *vpp = NULL; } len = cnp->cn_namelen; name = cnp->cn_nameptr; altname[0] = '\0'; /* * A "._" prefix means, we are looking for an associated file */ if (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR1 && *(name+1) == ASSOCCHAR2) { wantassoc = 1; len -= 2; name += 2; } /* * Decode search name into UCS-2 (Unicode) */ if ((imp->iso_ftype == ISO_FTYPE_JOLIET) && !((len == 1 && *name == '.') || (flags & ISDOTDOT))) { int flags = UTF_PRECOMPOSED; if (BYTE_ORDER != BIG_ENDIAN) flags |= UTF_REVERSE_ENDIAN; (void) utf8_decodestr(name, len, (u_int16_t*) altname, &altlen, sizeof(altname), 0, flags); name = altname; len = altlen; } /* * If there is cached information on a previous search of * this directory, pick up where we last left off. * We cache only lookups as these are the most common * and have the greatest payoff. Caching CREATE has little * benefit as it usually must search the entire directory * to determine that the entry does not exist. Caching the * location of the last DELETE or RENAME has not reduced * profiling time and hence has been removed in the interest * of simplicity. */ bmask = imp->im_sector_size - 1; if (nameiop != LOOKUP || dp->i_diroff == 0 || dp->i_diroff > dp->i_size) { entryoffsetinblock = 0; dp->i_offset = 0; numdirpasses = 1; } else { dp->i_offset = dp->i_diroff; if ((entryoffsetinblock = dp->i_offset & bmask) && (error = VOP_BLKATOFF(vdp, SECTOFF(imp, dp->i_offset), NULL, &bp))) return (error); numdirpasses = 2; iso_nchstats.ncs_2passes++; } endsearch = dp->i_size; searchloop: while (dp->i_offset < endsearch) { /* * If offset is on a block boundary, * read the next directory block. * Release previous if it exists. */ if ((dp->i_offset & bmask) == 0) { if (bp != NULL) brelse(bp); if ( (error = VOP_BLKATOFF(vdp, SECTOFF(imp,dp->i_offset), NULL, &bp)) ) return (error); entryoffsetinblock = 0; } /* * Get pointer to next entry. */ ep = (struct iso_directory_record *) ((char *)bp->b_data + entryoffsetinblock); reclen = isonum_711(ep->length); if (reclen == 0) { /* skip to next block, if any */ dp->i_offset = (dp->i_offset & ~bmask) + imp->im_sector_size; continue; } if (reclen < ISO_DIRECTORY_RECORD_SIZE) { /* illegal entry, stop */ break; } if (entryoffsetinblock + reclen > imp->im_sector_size) { /* entries are not allowed to cross sector boundaries */ break; } namelen = isonum_711(ep->name_len); isoflags = isonum_711(ep->flags); if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) /* illegal entry, stop */ break; /* * Check for a name match. */ if (imp->iso_ftype == ISO_FTYPE_RRIP) { if (isoflags & directoryBit) ino = isodirino(ep, imp); else ino = (bp->b_blkno << imp->im_bshift) + entryoffsetinblock; dp->i_ino = ino; cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); if (namelen == cnp->cn_namelen && !bcmp(name,altname,namelen)) goto found; ino = 0; } else { if ((!(isoflags & associatedBit)) == !wantassoc) { if ((len == 1 && *name == '.') || (flags & ISDOTDOT)) { if (namelen == 1 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { /* * Save directory entry's inode number and * release directory buffer. */ dp->i_ino = isodirino(ep, imp); goto found; } if (namelen != 1 || ep->name[0] != 0) goto notfound; } else if (imp->iso_ftype != ISO_FTYPE_JOLIET && !(res = isofncmp(name,len, ep->name,namelen))) { if ( isoflags & directoryBit ) ino = isodirino(ep, imp); else ino = (bp->b_blkno << imp->im_bshift) + entryoffsetinblock; saveoffset = dp->i_offset; } else if (imp->iso_ftype == ISO_FTYPE_JOLIET && !(res = ucsfncmp((u_int16_t*)name, len, (u_int16_t*) ep->name, namelen))) { if ( isoflags & directoryBit ) ino = isodirino(ep, imp); else ino = (bp->b_blkno << imp->im_bshift) + entryoffsetinblock; saveoffset = dp->i_offset; } else if (ino) goto foundino; #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ else if (res < 0) goto notfound; else if (res > 0 && numdirpasses == 2) numdirpasses++; #endif } } dp->i_offset += reclen; entryoffsetinblock += reclen; } /* endwhile */ if (ino) { foundino: dp->i_ino = ino; if (saveoffset != dp->i_offset) { if (lblkno(imp, dp->i_offset) != lblkno(imp, saveoffset)) { if (bp != NULL) brelse(bp); if ( (error = VOP_BLKATOFF(vdp, SECTOFF(imp, saveoffset), NULL, &bp)) ) return (error); } entryoffsetinblock = saveoffset & bmask; ep = (struct iso_directory_record *) ((char *)bp->b_data + entryoffsetinblock); dp->i_offset = saveoffset; } goto found; } notfound: /* * If we started in the middle of the directory and failed * to find our target, we must check the beginning as well. */ if (numdirpasses == 2) { numdirpasses--; dp->i_offset = 0; endsearch = dp->i_diroff; goto searchloop; } if (bp != NULL) brelse(bp); /* * Insert name into cache (as non-existent) if appropriate. */ if (cnp->cn_flags & MAKEENTRY) cache_enter(vdp, *vpp, cnp); if (nameiop == CREATE || nameiop == RENAME) { /* * return EROFS (NOT EJUSTRETURN). The caller will then unlock * the parent for us. */ return (EROFS); } return (ENOENT); found: if (numdirpasses == 2) iso_nchstats.ncs_pass2++; /* * Found component in pathname. * If the final component of path name, save information * in the cache as to where the entry was found. */ if ((flags & ISLASTCN) && nameiop == LOOKUP) dp->i_diroff = dp->i_offset; /* * Step through the translation in the name. We do not `iput' the * directory because we may need it again if a symbolic link * is relative to the current directory. Instead we save it * unlocked as "pdp". We must get the target inode before unlocking * the directory to insure that the inode will not be removed * before we get it. We prevent deadlock by always fetching * inodes from the root, moving down the directory tree. Thus * when following backward pointers ".." we must unlock the * parent directory before getting the requested directory. * There is a potential race condition here if both the current * and parent directories are removed before the `iget' for the * inode associated with ".." returns. We hope that this occurs * infrequently since we cannot avoid this race condition without * implementing a sophisticated deadlock detection algorithm. * Note also that this simple deadlock detection scheme will not * work if the file system has any hard links other than ".." * that point backwards in the directory structure. */ pdp = vdp; /* * If ino is different from dp->i_ino, * it's a relocated directory. */ if (flags & ISDOTDOT) { VOP_UNLOCK(pdp, 0, p); /* race to get the inode */ error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, dp->i_ino != ino, ep, p); VTOI(tdp)->i_parent = VTOI(pdp)->i_number; brelse(bp); if (error) { VOP_LOCK(pdp, LK_EXCLUSIVE | LK_RETRY, p); return (error); } if (lockparent && (flags & ISLASTCN) && (error = VOP_LOCK(pdp, LK_EXCLUSIVE | LK_RETRY, p))) { vput(tdp); return (error); } *vpp = tdp; } else if (dp->i_number == dp->i_ino) { brelse(bp); VREF(vdp); /* we want ourself, ie "." */ *vpp = vdp; } else { error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, dp->i_ino != ino, ep, p); /* save parent inode number */ VTOI(tdp)->i_parent = VTOI(pdp)->i_number; brelse(bp); if (error) return (error); if (!lockparent || !(flags & ISLASTCN)) VOP_UNLOCK(pdp, 0, p); *vpp = tdp; } /* * Insert name into cache if appropriate. */ if (cnp->cn_flags & MAKEENTRY) cache_enter(vdp, *vpp, cnp); return (0); } /* * Return buffer with the contents of block "offset" from the beginning of * directory "ip". If "res" is non-zero, fill it in with a pointer to the * remaining space in the directory. */ int cd9660_blkatoff(ap) struct vop_blkatoff_args /* { struct vnode *a_vp; off_t a_offset; char **a_res; struct buf **a_bpp; } */ *ap; { struct iso_node *ip; register struct iso_mnt *imp; struct buf *bp; daddr_t lbn; int bsize, error; ip = VTOI(ap->a_vp); imp = ip->i_mnt; lbn = lblkno(imp, ap->a_offset); bsize = blksize(imp, ip, lbn); if ((bsize != imp->im_sector_size) && (ap->a_offset & (imp->im_sector_size - 1)) == 0) { bsize = imp->im_sector_size; } if ( (error = bread(ap->a_vp, lbn, bsize, NOCRED, &bp)) ) { brelse(bp); *ap->a_bpp = NULL; return (error); } if (ap->a_res) *ap->a_res = (char *)bp->b_data + blkoff(imp, ap->a_offset); *ap->a_bpp = bp; return (0); }