/*- * modified for Lites 1.1 * * Aug 1995, Godmar Back (gback@cs.utah.edu) * University of Utah, Department of Computer Science */ /*- * Copyright (c) 1989, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * 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. * 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. * * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94 * $FreeBSD$ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INVARIANTS static int dirchk = 1; #else static int dirchk = 0; #endif static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem"); SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, ""); /* DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512) while it is the native blocksize in ext2fs - thus, a #define is no longer appropriate */ #undef DIRBLKSIZ static u_char ext2_ft_to_dt[] = { DT_UNKNOWN, /* EXT2_FT_UNKNOWN */ DT_REG, /* EXT2_FT_REG_FILE */ DT_DIR, /* EXT2_FT_DIR */ DT_CHR, /* EXT2_FT_CHRDEV */ DT_BLK, /* EXT2_FT_BLKDEV */ DT_FIFO, /* EXT2_FT_FIFO */ DT_SOCK, /* EXT2_FT_SOCK */ DT_LNK, /* EXT2_FT_SYMLINK */ }; #define FTTODT(ft) \ ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN) static u_char dt_to_ext2_ft[] = { EXT2_FT_UNKNOWN, /* DT_UNKNOWN */ EXT2_FT_FIFO, /* DT_FIFO */ EXT2_FT_CHRDEV, /* DT_CHR */ EXT2_FT_UNKNOWN, /* unused */ EXT2_FT_DIR, /* DT_DIR */ EXT2_FT_UNKNOWN, /* unused */ EXT2_FT_BLKDEV, /* DT_BLK */ EXT2_FT_UNKNOWN, /* unused */ EXT2_FT_REG_FILE, /* DT_REG */ EXT2_FT_UNKNOWN, /* unused */ EXT2_FT_SYMLINK, /* DT_LNK */ EXT2_FT_UNKNOWN, /* unused */ EXT2_FT_SOCK, /* DT_SOCK */ EXT2_FT_UNKNOWN, /* unused */ EXT2_FT_UNKNOWN, /* DT_WHT */ }; #define DTTOFT(dt) \ ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN) static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, int entryoffsetinblock); static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp, ino_t *dd_ino); /* * Vnode op for reading directories. */ int ext2_readdir(struct vop_readdir_args *ap) { struct vnode *vp = ap->a_vp; struct uio *uio = ap->a_uio; struct buf *bp; struct inode *ip; struct ext2fs_direct_2 *dp, *edp; u_long *cookies; struct dirent dstdp; off_t offset, startoffset; size_t readcnt, skipcnt; ssize_t startresid; int ncookies; int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize; int error; if (uio->uio_offset < 0) return (EINVAL); ip = VTOI(vp); if (ap->a_ncookies != NULL) { ncookies = uio->uio_resid; if (uio->uio_offset >= ip->i_size) ncookies = 0; else if (ip->i_size - uio->uio_offset < ncookies) ncookies = ip->i_size - uio->uio_offset; ncookies = ncookies / (offsetof(struct ext2fs_direct_2, e2d_namlen) + 4) + 1; cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK); *ap->a_ncookies = ncookies; *ap->a_cookies = cookies; } else { ncookies = 0; cookies = NULL; } offset = startoffset = uio->uio_offset; startresid = uio->uio_resid; error = 0; while (error == 0 && uio->uio_resid > 0 && uio->uio_offset < ip->i_size) { error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp); if (error) break; if (bp->b_offset + bp->b_bcount > ip->i_size) readcnt = ip->i_size - bp->b_offset; else readcnt = bp->b_bcount; skipcnt = (size_t)(uio->uio_offset - bp->b_offset) & ~(size_t)(DIRBLKSIZ - 1); offset = bp->b_offset + skipcnt; dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt]; edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt]; while (error == 0 && uio->uio_resid > 0 && dp < edp) { if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2, e2d_namlen) || (caddr_t)dp + dp->e2d_reclen > (caddr_t)edp) { error = EIO; break; } /*- * "New" ext2fs directory entries differ in 3 ways * from ufs on-disk ones: * - the name is not necessarily NUL-terminated. * - the file type field always exists and always * follows the name length field. * - the file type is encoded in a different way. * * "Old" ext2fs directory entries need no special * conversions, since they are binary compatible * with "new" entries having a file type of 0 (i.e., * EXT2_FT_UNKNOWN). Splitting the old name length * field didn't make a mess like it did in ufs, * because ext2fs uses a machine-independent disk * layout. */ dstdp.d_namlen = dp->e2d_namlen; dstdp.d_type = FTTODT(dp->e2d_type); if (offsetof(struct ext2fs_direct_2, e2d_namlen) + dstdp.d_namlen > dp->e2d_reclen) { error = EIO; break; } if (offset < startoffset || dp->e2d_ino == 0) goto nextentry; dstdp.d_fileno = dp->e2d_ino; dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp); bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen); dstdp.d_name[dstdp.d_namlen] = '\0'; if (dstdp.d_reclen > uio->uio_resid) { if (uio->uio_resid == startresid) error = EINVAL; else error = EJUSTRETURN; break; } /* Advance dp. */ error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio); if (error) break; if (cookies != NULL) { KASSERT(ncookies > 0, ("ext2_readdir: cookies buffer too small")); *cookies = offset + dp->e2d_reclen; cookies++; ncookies--; } nextentry: offset += dp->e2d_reclen; dp = (struct ext2fs_direct_2 *)((caddr_t)dp + dp->e2d_reclen); } bqrelse(bp); uio->uio_offset = offset; } /* We need to correct uio_offset. */ uio->uio_offset = offset; if (error == EJUSTRETURN) error = 0; if (ap->a_ncookies != NULL) { if (error == 0) { ap->a_ncookies -= ncookies; } else { free(*ap->a_cookies, M_TEMP); *ap->a_ncookies = 0; *ap->a_cookies = NULL; } } if (error == 0 && ap->a_eofflag) *ap->a_eofflag = ip->i_size <= uio->uio_offset; return (error); } /* * 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 cnp->cn_nameiop 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 vput * instead of two vputs. * * Overall outline of ext2_lookup: * * 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 */ int ext2_lookup(struct vop_cachedlookup_args *ap) { return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL)); } static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp, ino_t *dd_ino) { struct inode *dp; /* inode for directory being searched */ struct buf *bp; /* a buffer of directory entries */ struct ext2fs_direct_2 *ep; /* the current directory entry */ int entryoffsetinblock; /* offset of ep in bp's buffer */ enum {NONE, COMPACT, FOUND} slotstatus; doff_t slotoffset; /* offset of area with free space */ doff_t i_diroff; /* cached i_diroff value */ doff_t i_offset; /* cached i_offset value */ int slotsize; /* size of area at slotoffset */ int slotfreespace; /* amount of space free in slot */ int slotneeded; /* size of the entry we're seeking */ int numdirpasses; /* strategy for directory search */ doff_t endsearch; /* offset to end directory search */ doff_t prevoff; /* prev entry dp->i_offset */ struct vnode *pdp; /* saved dp during symlink work */ struct vnode *tdp; /* returned by VFS_VGET */ doff_t enduseful; /* pointer past last used dir slot */ u_long bmask; /* block offset mask */ int namlen, error; struct ucred *cred = cnp->cn_cred; int flags = cnp->cn_flags; int nameiop = cnp->cn_nameiop; ino_t ino, ino1; int ltype; int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize; if (vpp != NULL) *vpp = NULL; dp = VTOI(vdp); bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; restart: bp = NULL; slotoffset = -1; /* * We now have a segment name to search for, and a directory to search. */ /* * Suppress search for slots unless creating * file and at end of pathname, in which case * we watch for a place to put the new file in * case it doesn't already exist. */ i_diroff = dp->i_diroff; slotstatus = FOUND; slotfreespace = slotsize = slotneeded = 0; if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN)) { slotstatus = NONE; slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen); /* was slotneeded = (sizeof(struct direct) - MAXNAMLEN + cnp->cn_namelen + 3) &~ 3; */ } /* * 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. */ if (nameiop != LOOKUP || i_diroff == 0 || i_diroff > dp->i_size) { entryoffsetinblock = 0; i_offset = 0; numdirpasses = 1; } else { i_offset = i_diroff; if ((entryoffsetinblock = i_offset & bmask) && (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp))) return (error); numdirpasses = 2; nchstats.ncs_2passes++; } prevoff = i_offset; endsearch = roundup2(dp->i_size, DIRBLKSIZ); enduseful = 0; searchloop: while (i_offset < endsearch) { /* * If necessary, get the next directory block. */ if ((i_offset & bmask) == 0) { if (bp != NULL) brelse(bp); if ((error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp)) != 0) return (error); entryoffsetinblock = 0; } /* * If still looking for a slot, and at a DIRBLKSIZE * boundary, have to start looking for free space again. */ if (slotstatus == NONE && (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) { slotoffset = -1; slotfreespace = 0; } /* * Get pointer to next entry. * Full validation checks are slow, so we only check * enough to insure forward progress through the * directory. Complete checks can be run by setting * "vfs.e2fs.dirchk" to be true. */ ep = (struct ext2fs_direct_2 *) ((char *)bp->b_data + entryoffsetinblock); if (ep->e2d_reclen == 0 || (dirchk && ext2_dirbadentry(vdp, ep, entryoffsetinblock))) { int i; ext2_dirbad(dp, i_offset, "mangled entry"); i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)); i_offset += i; entryoffsetinblock += i; continue; } /* * If an appropriate sized slot has not yet been found, * check to see if one is available. Also accumulate space * in the current block so that we can determine if * compaction is viable. */ if (slotstatus != FOUND) { int size = ep->e2d_reclen; if (ep->e2d_ino != 0) size -= EXT2_DIR_REC_LEN(ep->e2d_namlen); if (size > 0) { if (size >= slotneeded) { slotstatus = FOUND; slotoffset = i_offset; slotsize = ep->e2d_reclen; } else if (slotstatus == NONE) { slotfreespace += size; if (slotoffset == -1) slotoffset = i_offset; if (slotfreespace >= slotneeded) { slotstatus = COMPACT; slotsize = i_offset + ep->e2d_reclen - slotoffset; } } } } /* * Check for a name match. */ if (ep->e2d_ino) { namlen = ep->e2d_namlen; if (namlen == cnp->cn_namelen && !bcmp(cnp->cn_nameptr, ep->e2d_name, (unsigned)namlen)) { /* * Save directory entry's inode number and * reclen in ndp->ni_ufs area, and release * directory buffer. */ ino = ep->e2d_ino; goto found; } } prevoff = i_offset; i_offset += ep->e2d_reclen; entryoffsetinblock += ep->e2d_reclen; if (ep->e2d_ino) enduseful = i_offset; } /* 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--; i_offset = 0; endsearch = i_diroff; goto searchloop; } if (bp != NULL) brelse(bp); /* * If creating, and at end of pathname and current * directory has not been removed, then can consider * allowing file to be created. */ if ((nameiop == CREATE || nameiop == RENAME) && (flags & ISLASTCN) && dp->i_nlink != 0) { /* * Access for write is interpreted as allowing * creation of files in the directory. */ if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) return (error); /* * Return an indication of where the new directory * entry should be put. If we didn't find a slot, * then set dp->i_count to 0 indicating * that the new slot belongs at the end of the * directory. If we found a slot, then the new entry * can be put in the range from dp->i_offset to * dp->i_offset + dp->i_count. */ if (slotstatus == NONE) { dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ); dp->i_count = 0; enduseful = dp->i_offset; } else { dp->i_offset = slotoffset; dp->i_count = slotsize; if (enduseful < slotoffset + slotsize) enduseful = slotoffset + slotsize; } dp->i_endoff = roundup2(enduseful, DIRBLKSIZ); /* * We return with the directory locked, so that * the parameters we set up above will still be * valid if we actually decide to do a direnter(). * We return ni_vp == NULL to indicate that the entry * does not currently exist; we leave a pointer to * the (locked) directory inode in ndp->ni_dvp. * The pathname buffer is saved so that the name * can be obtained later. * * NB - if the directory is unlocked, then this * information cannot be used. */ cnp->cn_flags |= SAVENAME; return (EJUSTRETURN); } /* * Insert name into cache (as non-existent) if appropriate. */ if ((cnp->cn_flags & MAKEENTRY) != 0) cache_enter(vdp, NULL, cnp); return (ENOENT); found: if (dd_ino != NULL) *dd_ino = ino; if (numdirpasses == 2) nchstats.ncs_pass2++; /* * Check that directory length properly reflects presence * of this entry. */ if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen) > dp->i_size) { ext2_dirbad(dp, i_offset, "i_size too small"); dp->i_size = entryoffsetinblock+EXT2_DIR_REC_LEN(ep->e2d_namlen); dp->i_flag |= IN_CHANGE | IN_UPDATE; } brelse(bp); /* * 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 = i_offset &~ (DIRBLKSIZ - 1); /* * If deleting, and at end of pathname, return * parameters which can be used to remove file. */ if (nameiop == DELETE && (flags & ISLASTCN)) { if (flags & LOCKPARENT) ASSERT_VOP_ELOCKED(vdp, __FUNCTION__); /* * Write access to directory required to delete files. */ if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) return (error); /* * Return pointer to current entry in dp->i_offset, * and distance past previous entry (if there * is a previous entry in this block) in dp->i_count. * Save directory inode pointer in ndp->ni_dvp for dirremove(). * * Technically we shouldn't be setting these in the * WANTPARENT case (first lookup in rename()), but any * lookups that will result in directory changes will * overwrite these. */ dp->i_offset = i_offset; if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0) dp->i_count = 0; else dp->i_count = dp->i_offset - prevoff; if (dd_ino != NULL) return (0); if (dp->i_number == ino) { VREF(vdp); *vpp = vdp; return (0); } if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, &tdp)) != 0) return (error); /* * If directory is "sticky", then user must own * the directory, or the file in it, else she * may not delete it (unless she's root). This * implements append-only directories. */ if ((dp->i_mode & ISVTX) && cred->cr_uid != 0 && cred->cr_uid != dp->i_uid && VTOI(tdp)->i_uid != cred->cr_uid) { vput(tdp); return (EPERM); } *vpp = tdp; return (0); } /* * If rewriting (RENAME), return the inode and the * information required to rewrite the present directory * Must get inode of directory entry to verify it's a * regular file, or empty directory. */ if (nameiop == RENAME && (flags & ISLASTCN)) { if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) return (error); /* * Careful about locking second inode. * This can only occur if the target is ".". */ dp->i_offset = i_offset; if (dp->i_number == ino) return (EISDIR); if (dd_ino != NULL) return (0); if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, &tdp)) != 0) return (error); *vpp = tdp; cnp->cn_flags |= SAVENAME; return (0); } if (dd_ino != NULL) return (0); /* * Step through the translation in the name. We do not `vput' 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 VFS_VGET 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 (flags & ISDOTDOT) { error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp); if (pdp->v_iflag & VI_DOOMED) { if (error == 0) vput(tdp); error = ENOENT; } if (error) return (error); /* * Recheck that ".." entry in the vdp directory points * to the inode we looked up before vdp lock was * dropped. */ error = ext2_lookup_ino(pdp, NULL, cnp, &ino1); if (error) { vput(tdp); return (error); } if (ino1 != ino) { vput(tdp); goto restart; } *vpp = tdp; } else if (dp->i_number == ino) { VREF(vdp); /* we want ourself, ie "." */ /* * When we lookup "." we still can be asked to lock it * differently. */ ltype = cnp->cn_lkflags & LK_TYPE_MASK; if (ltype != VOP_ISLOCKED(vdp)) { if (ltype == LK_EXCLUSIVE) vn_lock(vdp, LK_UPGRADE | LK_RETRY); else /* if (ltype == LK_SHARED) */ vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); } *vpp = vdp; } else { if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags, &tdp)) != 0) return (error); *vpp = tdp; } /* * Insert name into cache if appropriate. */ if (cnp->cn_flags & MAKEENTRY) cache_enter(vdp, *vpp, cnp); return (0); } void ext2_dirbad(struct inode *ip, doff_t offset, char *how) { struct mount *mp; mp = ITOV(ip)->v_mount; if ((mp->mnt_flag & MNT_RDONLY) == 0) panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n", mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number, (long)offset, how); else (void)printf("%s: bad dir ino %ju at offset %ld: %s\n", mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number, (long)offset, how); } /* * Do consistency checking on a directory entry: * record length must be multiple of 4 * entry must fit in rest of its DIRBLKSIZ block * record must be large enough to contain entry * name is not longer than MAXNAMLEN * name must be as long as advertised, and null terminated */ /* * changed so that it confirms to ext2_check_dir_entry */ static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, int entryoffsetinblock) { int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize; char * error_msg = NULL; if (de->e2d_reclen < EXT2_DIR_REC_LEN(1)) error_msg = "rec_len is smaller than minimal"; else if (de->e2d_reclen % 4 != 0) error_msg = "rec_len % 4 != 0"; else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen)) error_msg = "reclen is too small for name_len"; else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ) error_msg = "directory entry across blocks"; /* else LATER if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count) error_msg = "inode out of bounds"; */ if (error_msg != NULL) { printf("bad directory entry: %s\n", error_msg); printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n", entryoffsetinblock, (unsigned long)de->e2d_ino, de->e2d_reclen, de->e2d_namlen); } return error_msg == NULL ? 0 : 1; } /* * Write a directory entry after a call to namei, using the parameters * that it left in nameidata. The argument ip is the inode which the new * directory entry will refer to. Dvp is a pointer to the directory to * be written, which was left locked by namei. Remaining parameters * (dp->i_offset, dp->i_count) indicate how the space for the new * entry is to be obtained. */ int ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp) { struct ext2fs_direct_2 *ep, *nep; struct inode *dp; struct buf *bp; struct ext2fs_direct_2 newdir; struct iovec aiov; struct uio auio; u_int dsize; int error, loc, newentrysize, spacefree; char *dirbuf; int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize; #ifdef INVARIANTS if ((cnp->cn_flags & SAVENAME) == 0) panic("ext2_direnter: missing name"); #endif dp = VTOI(dvp); newdir.e2d_ino = ip->i_number; newdir.e2d_namlen = cnp->cn_namelen; if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, EXT2F_INCOMPAT_FTYPE)) newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode)); else newdir.e2d_type = EXT2_FT_UNKNOWN; bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1); newentrysize = EXT2_DIR_REC_LEN(newdir.e2d_namlen); if (dp->i_count == 0) { /* * If dp->i_count is 0, then namei could find no * space in the directory. Here, dp->i_offset will * be on a directory block boundary and we will write the * new entry into a fresh block. */ if (dp->i_offset & (DIRBLKSIZ - 1)) panic("ext2_direnter: newblk"); auio.uio_offset = dp->i_offset; newdir.e2d_reclen = DIRBLKSIZ; auio.uio_resid = newentrysize; aiov.iov_len = newentrysize; aiov.iov_base = (caddr_t)&newdir; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_rw = UIO_WRITE; auio.uio_segflg = UIO_SYSSPACE; auio.uio_td = (struct thread *)0; error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred); if (DIRBLKSIZ > VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize) /* XXX should grow with balloc() */ panic("ext2_direnter: frag size"); else if (!error) { dp->i_size = roundup2(dp->i_size, DIRBLKSIZ); dp->i_flag |= IN_CHANGE; } return (error); } /* * If dp->i_count is non-zero, then namei found space * for the new entry in the range dp->i_offset to * dp->i_offset + dp->i_count in the directory. * To use this space, we may have to compact the entries located * there, by copying them together towards the beginning of the * block, leaving the free space in one usable chunk at the end. */ /* * Increase size of directory if entry eats into new space. * This should never push the size past a new multiple of * DIRBLKSIZE. * * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. */ if (dp->i_offset + dp->i_count > dp->i_size) dp->i_size = dp->i_offset + dp->i_count; /* * Get the block containing the space for the new directory entry. */ if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf, &bp)) != 0) return (error); /* * Find space for the new entry. In the simple case, the entry at * offset base will have the space. If it does not, then namei * arranged that compacting the region dp->i_offset to * dp->i_offset + dp->i_count would yield the * space. */ ep = (struct ext2fs_direct_2 *)dirbuf; dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen); spacefree = ep->e2d_reclen - dsize; for (loc = ep->e2d_reclen; loc < dp->i_count; ) { nep = (struct ext2fs_direct_2 *)(dirbuf + loc); if (ep->e2d_ino) { /* trim the existing slot */ ep->e2d_reclen = dsize; ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); } else { /* overwrite; nothing there; header is ours */ spacefree += dsize; } dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen); spacefree += nep->e2d_reclen - dsize; loc += nep->e2d_reclen; bcopy((caddr_t)nep, (caddr_t)ep, dsize); } /* * Update the pointer fields in the previous entry (if any), * copy in the new entry, and write out the block. */ if (ep->e2d_ino == 0) { if (spacefree + dsize < newentrysize) panic("ext2_direnter: compact1"); newdir.e2d_reclen = spacefree + dsize; } else { if (spacefree < newentrysize) panic("ext2_direnter: compact2"); newdir.e2d_reclen = spacefree; ep->e2d_reclen = dsize; ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); } bcopy((caddr_t)&newdir, (caddr_t)ep, (u_int)newentrysize); if (DOINGASYNC(dvp)) { bdwrite(bp); error = 0; } else { error = bwrite(bp); } dp->i_flag |= IN_CHANGE | IN_UPDATE; if (!error && dp->i_endoff && dp->i_endoff < dp->i_size) error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC, cnp->cn_cred, cnp->cn_thread); return (error); } /* * Remove a directory entry after a call to namei, using * the parameters which it left in nameidata. The entry * dp->i_offset contains the offset into the directory of the * entry to be eliminated. The dp->i_count field contains the * size of the previous record in the directory. If this * is 0, the first entry is being deleted, so we need only * zero the inode number to mark the entry as free. If the * entry is not the first in the directory, we must reclaim * the space of the now empty record by adding the record size * to the size of the previous entry. */ int ext2_dirremove(struct vnode *dvp, struct componentname *cnp) { struct inode *dp; struct ext2fs_direct_2 *ep, *rep; struct buf *bp; int error; dp = VTOI(dvp); if (dp->i_count == 0) { /* * First entry in block: set d_ino to zero. */ if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0) return (error); ep->e2d_ino = 0; error = bwrite(bp); dp->i_flag |= IN_CHANGE | IN_UPDATE; return (error); } /* * Collapse new free space into previous entry. */ if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count), (char **)&ep, &bp)) != 0) return (error); /* Set 'rep' to the entry being removed. */ if (dp->i_count == 0) rep = ep; else rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen); ep->e2d_reclen += rep->e2d_reclen; if (DOINGASYNC(dvp) && dp->i_count != 0) bdwrite(bp); else error = bwrite(bp); dp->i_flag |= IN_CHANGE | IN_UPDATE; return (error); } /* * Rewrite an existing directory entry to point at the inode * supplied. The parameters describing the directory entry are * set up by a call to namei. */ int ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp) { struct buf *bp; struct ext2fs_direct_2 *ep; struct vnode *vdp = ITOV(dp); int error; if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0) return (error); ep->e2d_ino = ip->i_number; if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, EXT2F_INCOMPAT_FTYPE)) ep->e2d_type = DTTOFT(IFTODT(ip->i_mode)); else ep->e2d_type = EXT2_FT_UNKNOWN; error = bwrite(bp); dp->i_flag |= IN_CHANGE | IN_UPDATE; return (error); } /* * Check if a directory is empty or not. * Inode supplied must be locked. * * Using a struct dirtemplate here is not precisely * what we want, but better than using a struct direct. * * NB: does not handle corrupted directories. */ int ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred) { off_t off; struct dirtemplate dbuf; struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf; int error, namlen; ssize_t count; #define MINDIRSIZ (sizeof(struct dirtemplate) / 2) for (off = 0; off < ip->i_size; off += dp->e2d_reclen) { error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, &count, (struct thread *)0); /* * Since we read MINDIRSIZ, residual must * be 0 unless we're at end of file. */ if (error || count != 0) return (0); /* avoid infinite loops */ if (dp->e2d_reclen == 0) return (0); /* skip empty entries */ if (dp->e2d_ino == 0) continue; /* accept only "." and ".." */ namlen = dp->e2d_namlen; if (namlen > 2) return (0); if (dp->e2d_name[0] != '.') return (0); /* * At this point namlen must be 1 or 2. * 1 implies ".", 2 implies ".." if second * char is also "." */ if (namlen == 1) continue; if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino) continue; return (0); } return (1); } /* * Check if source directory is in the path of the target directory. * Target is supplied locked, source is unlocked. * The target is always vput before returning. */ int ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred) { struct vnode *vp; int error, namlen; struct dirtemplate dirbuf; vp = ITOV(target); if (target->i_number == source->i_number) { error = EEXIST; goto out; } if (target->i_number == EXT2_ROOTINO) { error = 0; goto out; } for (;;) { if (vp->v_type != VDIR) { error = ENOTDIR; break; } error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf, sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, NULL); if (error != 0) break; namlen = dirbuf.dotdot_type; /* like ufs little-endian */ if (namlen != 2 || dirbuf.dotdot_name[0] != '.' || dirbuf.dotdot_name[1] != '.') { error = ENOTDIR; break; } if (dirbuf.dotdot_ino == source->i_number) { error = EINVAL; break; } if (dirbuf.dotdot_ino == EXT2_ROOTINO) break; vput(vp); if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, LK_EXCLUSIVE, &vp)) != 0) { vp = NULL; break; } } out: if (error == ENOTDIR) printf("checkpath: .. not a directory\n"); if (vp != NULL) vput(vp); return (error); }