diff options
Diffstat (limited to 'sys/kern/vfs_lookup.c')
| -rw-r--r-- | sys/kern/vfs_lookup.c | 165 |
1 files changed, 160 insertions, 5 deletions
diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c index a6e9469..d1b19ce 100644 --- a/sys/kern/vfs_lookup.c +++ b/sys/kern/vfs_lookup.c @@ -36,7 +36,7 @@ * SUCH DAMAGE. * * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94 - * $Id: vfs_lookup.c,v 1.3 1994/08/18 22:35:08 wollman Exp $ + * $Id: vfs_lookup.c,v 1.4 1994/08/20 03:48:49 davidg Exp $ */ #include <sys/param.h> @@ -144,7 +144,8 @@ namei(ndp) VREF(dp); } ndp->ni_startdir = dp; - if (error = lookup(ndp)) { + error = lookup(ndp); + if (error) { FREE(cnp->cn_pnbuf, M_NAMEI); return (error); } @@ -177,7 +178,8 @@ namei(ndp) auio.uio_segflg = UIO_SYSSPACE; auio.uio_procp = (struct proc *)0; auio.uio_resid = MAXPATHLEN; - if (error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred)) { + error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); + if (error) { if (ndp->ni_pathlen > 1) free(cp, M_NAMEI); break; @@ -374,7 +376,8 @@ dirloop: */ unionlookup: ndp->ni_dvp = dp; - if (error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) { + error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp); + if (error) { #ifdef DIAGNOSTIC if (ndp->ni_vp != NULL) panic("leaf should be empty"); @@ -450,7 +453,8 @@ unionlookup: sleep((caddr_t)mp, PVFS); continue; } - if (error = VFS_ROOT(dp->v_mountedhere, &tdp)) + error = VFS_ROOT(dp->v_mountedhere, &tdp); + if (error) goto bad2; vput(dp); ndp->ni_vp = dp = tdp; @@ -505,4 +509,155 @@ bad: return (error); } +/* + * relookup - lookup a path name component + * Used by lookup to re-aquire things. + */ +int +relookup(dvp, vpp, cnp) + struct vnode *dvp, **vpp; + struct componentname *cnp; +{ + register struct vnode *dp = 0; /* the directory we are searching */ + int docache; /* == 0 do not cache last component */ + int wantparent; /* 1 => wantparent or lockparent flag */ + int rdonly; /* lookup read-only flag bit */ + int error = 0; +#ifdef NAMEI_DIAGNOSTIC + int newhash; /* DEBUG: check name hash */ + char *cp; /* DEBUG: check name ptr/len */ +#endif + + /* + * Setup: break out flag bits into variables. + */ + wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT); + docache = (cnp->cn_flags & NOCACHE) ^ NOCACHE; + if (cnp->cn_nameiop == DELETE || + (wantparent && cnp->cn_nameiop != CREATE)) + docache = 0; + rdonly = cnp->cn_flags & RDONLY; + cnp->cn_flags &= ~ISSYMLINK; + dp = dvp; + VOP_LOCK(dp); + +/* dirloop: */ + /* + * Search a new directory. + * + * The cn_hash value is for use by vfs_cache. + * The last component of the filename is left accessible via + * cnp->cn_nameptr for callers that need the name. Callers needing + * the name set the SAVENAME flag. When done, they assume + * responsibility for freeing the pathname buffer. + */ +#ifdef NAMEI_DIAGNOSTIC + for (newhash = 0, cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) + newhash += (unsigned char)*cp; + if (newhash != cnp->cn_hash) + panic("relookup: bad hash"); + if (cnp->cn_namelen != cp - cnp->cn_nameptr) + panic ("relookup: bad len"); + if (*cp != 0) + panic("relookup: not last component"); + printf("{%s}: ", cnp->cn_nameptr); +#endif + + /* + * Check for degenerate name (e.g. / or "") + * which is a way of talking about a directory, + * e.g. like "/." or ".". + */ + if (cnp->cn_nameptr[0] == '\0') { + if (cnp->cn_nameiop != LOOKUP || wantparent) { + error = EISDIR; + goto bad; + } + if (dp->v_type != VDIR) { + error = ENOTDIR; + goto bad; + } + if (!(cnp->cn_flags & LOCKLEAF)) + VOP_UNLOCK(dp); + *vpp = dp; + if (cnp->cn_flags & SAVESTART) + panic("lookup: SAVESTART"); + return (0); + } + + if (cnp->cn_flags & ISDOTDOT) + panic ("relookup: lookup on dot-dot"); + /* + * We now have a segment name to search for, and a directory to search. + */ + error = VOP_LOOKUP(dp, vpp, cnp); + if (error) { +#ifdef DIAGNOSTIC + if (*vpp != NULL) + panic("leaf should be empty"); +#endif + if (error != EJUSTRETURN) + goto bad; + /* + * If creating and at end of pathname, then can consider + * allowing file to be created. + */ + if (rdonly || (dvp->v_mount->mnt_flag & MNT_RDONLY)) { + error = EROFS; + goto bad; + } + /* ASSERT(dvp == ndp->ni_startdir) */ + if (cnp->cn_flags & SAVESTART) + VREF(dvp); + /* + * We return with ni_vp NULL to indicate that the entry + * doesn't currently exist, leaving a pointer to the + * (possibly locked) directory inode in ndp->ni_dvp. + */ + return (0); + } + dp = *vpp; + +#ifdef DIAGNOSTIC + /* + * Check for symbolic link + */ + if (dp->v_type == VLNK && (cnp->cn_flags & FOLLOW)) + panic ("relookup: symlink found.\n"); +#endif + + /* + * Check for read-only file systems. + */ + if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME) { + /* + * Disallow directory write attempts on read-only + * file systems. + */ + if (rdonly || (dp->v_mount->mnt_flag & MNT_RDONLY) || + (wantparent && + (dvp->v_mount->mnt_flag & MNT_RDONLY))) { + error = EROFS; + goto bad2; + } + } + /* ASSERT(dvp == ndp->ni_startdir) */ + if (cnp->cn_flags & SAVESTART) + VREF(dvp); + + if (!wantparent) + vrele(dvp); + if ((cnp->cn_flags & LOCKLEAF) == 0) + VOP_UNLOCK(dp); + return (0); + +bad2: + if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) + VOP_UNLOCK(dvp); + vrele(dvp); +bad: + vput(dp); + *vpp = NULL; + return (error); +} |
