diff options
Diffstat (limited to 'sys/kern/vfs_lookup.c')
| -rw-r--r-- | sys/kern/vfs_lookup.c | 754 |
1 files changed, 754 insertions, 0 deletions
diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c new file mode 100644 index 0000000..8e4af42 --- /dev/null +++ b/sys/kern/vfs_lookup.c @@ -0,0 +1,754 @@ +/* + * Copyright (c) 1982, 1986, 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. + * 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. + * + * @(#)vfs_lookup.c 8.4 (Berkeley) 2/16/94 + * $FreeBSD$ + */ + +#include "opt_ktrace.h" + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/namei.h> +#include <sys/vnode.h> +#include <sys/mount.h> +#include <sys/filedesc.h> +#include <sys/proc.h> +#ifdef KTRACE +#include <sys/ktrace.h> +#endif + +#include <vm/uma.h> + +/* + * Allocation zone for namei + */ +uma_zone_t namei_zone; + +static void +nameiinit(void *dummy __unused) +{ + namei_zone = uma_zcreate("NAMEI", MAXPATHLEN, NULL, NULL, NULL, NULL, + UMA_ALIGN_PTR, 0); + +} +SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nameiinit, NULL) + +/* + * Convert a pathname into a pointer to a locked inode. + * + * The FOLLOW flag is set when symbolic links are to be followed + * when they occur at the end of the name translation process. + * Symbolic links are always followed for all other pathname + * components other than the last. + * + * The segflg defines whether the name is to be copied from user + * space or kernel space. + * + * Overall outline of namei: + * + * copy in name + * get starting directory + * while (!done && !error) { + * call lookup to search path. + * if symbolic link, massage name in buffer and continue + * } + */ +int +namei(ndp) + register struct nameidata *ndp; +{ + register struct filedesc *fdp; /* pointer to file descriptor state */ + register char *cp; /* pointer into pathname argument */ + register struct vnode *dp; /* the directory we are searching */ + struct iovec aiov; /* uio for reading symbolic links */ + struct uio auio; + int error, linklen; + struct componentname *cnp = &ndp->ni_cnd; + struct thread *td = cnp->cn_thread; + struct proc *p = td->td_proc; + + ndp->ni_cnd.cn_cred = ndp->ni_cnd.cn_thread->td_ucred; + KASSERT(cnp->cn_cred && p, ("namei: bad cred/proc")); + KASSERT((cnp->cn_nameiop & (~OPMASK)) == 0, + ("namei: nameiop contaminated with flags")); + KASSERT((cnp->cn_flags & OPMASK) == 0, + ("namei: flags contaminated with nameiops")); + fdp = p->p_fd; + + /* + * Get a buffer for the name to be translated, and copy the + * name into the buffer. + */ + if ((cnp->cn_flags & HASBUF) == 0) + cnp->cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK); + if (ndp->ni_segflg == UIO_SYSSPACE) + error = copystr(ndp->ni_dirp, cnp->cn_pnbuf, + MAXPATHLEN, (size_t *)&ndp->ni_pathlen); + else + error = copyinstr(ndp->ni_dirp, cnp->cn_pnbuf, + MAXPATHLEN, (size_t *)&ndp->ni_pathlen); + + /* + * Don't allow empty pathnames. + */ + if (!error && *cnp->cn_pnbuf == '\0') + error = ENOENT; + + if (error) { + uma_zfree(namei_zone, cnp->cn_pnbuf); + ndp->ni_vp = NULL; + return (error); + } + ndp->ni_loopcnt = 0; +#ifdef KTRACE + if (KTRPOINT(td, KTR_NAMEI)) { + KASSERT(cnp->cn_thread == curthread, + ("namei not using curthread")); + ktrnamei(cnp->cn_pnbuf); + } +#endif + + /* + * Get starting point for the translation. + */ + FILEDESC_LOCK(fdp); + ndp->ni_rootdir = fdp->fd_rdir; + ndp->ni_topdir = fdp->fd_jdir; + + dp = fdp->fd_cdir; + VREF(dp); + FILEDESC_UNLOCK(fdp); + for (;;) { + /* + * Check if root directory should replace current directory. + * Done at start of translation and after symbolic link. + */ + cnp->cn_nameptr = cnp->cn_pnbuf; + if (*(cnp->cn_nameptr) == '/') { + vrele(dp); + while (*(cnp->cn_nameptr) == '/') { + cnp->cn_nameptr++; + ndp->ni_pathlen--; + } + dp = ndp->ni_rootdir; + VREF(dp); + } + ndp->ni_startdir = dp; + error = lookup(ndp); + if (error) { + uma_zfree(namei_zone, cnp->cn_pnbuf); + return (error); + } + /* + * Check for symbolic link + */ + if ((cnp->cn_flags & ISSYMLINK) == 0) { + if ((cnp->cn_flags & (SAVENAME | SAVESTART)) == 0) + uma_zfree(namei_zone, cnp->cn_pnbuf); + else + cnp->cn_flags |= HASBUF; + + if (vn_canvmio(ndp->ni_vp) == TRUE && + (cnp->cn_nameiop != DELETE) && + ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == + LOCKLEAF)) + vfs_object_create(ndp->ni_vp, td, + ndp->ni_cnd.cn_cred); + + return (0); + } + if ((cnp->cn_flags & LOCKPARENT) && ndp->ni_pathlen == 1) + VOP_UNLOCK(ndp->ni_dvp, 0, td); + if (ndp->ni_loopcnt++ >= MAXSYMLINKS) { + error = ELOOP; + break; + } + if (ndp->ni_pathlen > 1) + cp = uma_zalloc(namei_zone, M_WAITOK); + else + cp = cnp->cn_pnbuf; + aiov.iov_base = cp; + aiov.iov_len = MAXPATHLEN; + auio.uio_iov = &aiov; + auio.uio_iovcnt = 1; + auio.uio_offset = 0; + auio.uio_rw = UIO_READ; + auio.uio_segflg = UIO_SYSSPACE; + auio.uio_td = (struct thread *)0; + auio.uio_resid = MAXPATHLEN; + error = VOP_READLINK(ndp->ni_vp, &auio, cnp->cn_cred); + if (error) { + if (ndp->ni_pathlen > 1) + uma_zfree(namei_zone, cp); + break; + } + linklen = MAXPATHLEN - auio.uio_resid; + if (linklen == 0) { + if (ndp->ni_pathlen > 1) + uma_zfree(namei_zone, cp); + error = ENOENT; + break; + } + if (linklen + ndp->ni_pathlen >= MAXPATHLEN) { + if (ndp->ni_pathlen > 1) + uma_zfree(namei_zone, cp); + error = ENAMETOOLONG; + break; + } + if (ndp->ni_pathlen > 1) { + bcopy(ndp->ni_next, cp + linklen, ndp->ni_pathlen); + uma_zfree(namei_zone, cnp->cn_pnbuf); + cnp->cn_pnbuf = cp; + } else + cnp->cn_pnbuf[linklen] = '\0'; + ndp->ni_pathlen += linklen; + vput(ndp->ni_vp); + dp = ndp->ni_dvp; + } + uma_zfree(namei_zone, cnp->cn_pnbuf); + vrele(ndp->ni_dvp); + vput(ndp->ni_vp); + ndp->ni_vp = NULL; + return (error); +} + +/* + * Search a pathname. + * This is a very central and rather complicated routine. + * + * The pathname is pointed to by ni_ptr and is of length ni_pathlen. + * The starting directory is taken from ni_startdir. The pathname is + * descended until done, or a symbolic link is encountered. The variable + * ni_more is clear if the path is completed; it is set to one if a + * symbolic link needing interpretation is encountered. + * + * 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, the parent directory is returned + * locked. If flag has WANTPARENT or'ed into it, the parent directory is + * returned unlocked. Otherwise the parent directory is not returned. If + * the target of the pathname exists and LOCKLEAF is or'ed into the flag + * the target is returned locked, otherwise it is returned unlocked. + * When creating or renaming and LOCKPARENT is specified, the target may not + * be ".". When deleting and LOCKPARENT is specified, the target may be ".". + * + * Overall outline of lookup: + * + * dirloop: + * identify next component of name at ndp->ni_ptr + * handle degenerate case where name is null string + * if .. and crossing mount points and on mounted filesys, find parent + * call VOP_LOOKUP routine for next component name + * directory vnode returned in ni_dvp, unlocked unless LOCKPARENT set + * component vnode returned in ni_vp (if it exists), locked. + * if result vnode is mounted on and crossing mount points, + * find mounted on vnode + * if more components of name, do next level at dirloop + * return the answer in ni_vp, locked if LOCKLEAF set + * if LOCKPARENT set, return locked parent in ni_dvp + * if WANTPARENT set, return unlocked parent in ni_dvp + */ +int +lookup(ndp) + register struct nameidata *ndp; +{ + register char *cp; /* pointer into pathname argument */ + register struct vnode *dp = 0; /* the directory we are searching */ + struct vnode *tdp; /* saved dp */ + struct mount *mp; /* mount table entry */ + int docache; /* == 0 do not cache last component */ + int wantparent; /* 1 => wantparent or lockparent flag */ + int rdonly; /* lookup read-only flag bit */ + int trailing_slash; + int error = 0; + int dpunlocked = 0; /* dp has already been unlocked */ + struct componentname *cnp = &ndp->ni_cnd; + struct thread *td = cnp->cn_thread; + + /* + * 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 && + cnp->cn_nameiop != LOOKUP)) + docache = 0; + rdonly = cnp->cn_flags & RDONLY; + ndp->ni_dvp = NULL; + cnp->cn_flags &= ~ISSYMLINK; + dp = ndp->ni_startdir; + ndp->ni_startdir = NULLVP; + vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); + +dirloop: + /* + * Search a new directory. + * + * 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. + */ + cnp->cn_consume = 0; + for (cp = cnp->cn_nameptr; *cp != 0 && *cp != '/'; cp++) + continue; + cnp->cn_namelen = cp - cnp->cn_nameptr; + if (cnp->cn_namelen > NAME_MAX) { + error = ENAMETOOLONG; + goto bad; + } +#ifdef NAMEI_DIAGNOSTIC + { char c = *cp; + *cp = '\0'; + printf("{%s}: ", cnp->cn_nameptr); + *cp = c; } +#endif + ndp->ni_pathlen -= cnp->cn_namelen; + ndp->ni_next = cp; + + /* + * Replace multiple slashes by a single slash and trailing slashes + * by a null. This must be done before VOP_LOOKUP() because some + * fs's don't know about trailing slashes. Remember if there were + * trailing slashes to handle symlinks, existing non-directories + * and non-existing files that won't be directories specially later. + */ + trailing_slash = 0; + while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) { + cp++; + ndp->ni_pathlen--; + if (*cp == '\0') { + trailing_slash = 1; + *ndp->ni_next = '\0'; /* XXX for direnter() ... */ + } + } + ndp->ni_next = cp; + + cnp->cn_flags |= MAKEENTRY; + if (*cp == '\0' && docache == 0) + cnp->cn_flags &= ~MAKEENTRY; + if (cnp->cn_namelen == 2 && + cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.') + cnp->cn_flags |= ISDOTDOT; + else + cnp->cn_flags &= ~ISDOTDOT; + if (*ndp->ni_next == 0) + cnp->cn_flags |= ISLASTCN; + else + cnp->cn_flags &= ~ISLASTCN; + + + /* + * 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 (dp->v_type != VDIR) { + error = ENOTDIR; + goto bad; + } + if (cnp->cn_nameiop != LOOKUP) { + error = EISDIR; + goto bad; + } + if (wantparent) { + ndp->ni_dvp = dp; + VREF(dp); + } + ndp->ni_vp = dp; + if (!(cnp->cn_flags & (LOCKPARENT | LOCKLEAF))) + VOP_UNLOCK(dp, 0, td); + /* XXX This should probably move to the top of function. */ + if (cnp->cn_flags & SAVESTART) + panic("lookup: SAVESTART"); + return (0); + } + + /* + * Handle "..": two special cases. + * 1. If at root directory (e.g. after chroot) + * or at absolute root directory + * then ignore it so can't get out. + * 2. If this vnode is the root of a mounted + * filesystem, then replace it with the + * vnode which was mounted on so we take the + * .. in the other filesystem. + * 3. If the vnode is the top directory of + * the jail or chroot, don't let them out. + */ + if (cnp->cn_flags & ISDOTDOT) { + for (;;) { + if (dp == ndp->ni_rootdir || + dp == ndp->ni_topdir || + dp == rootvnode) { + ndp->ni_dvp = dp; + ndp->ni_vp = dp; + VREF(dp); + goto nextname; + } + if ((dp->v_flag & VROOT) == 0 || + (cnp->cn_flags & NOCROSSMOUNT)) + break; + if (dp->v_mount == NULL) { /* forced unmount */ + error = EBADF; + goto bad; + } + tdp = dp; + dp = dp->v_mount->mnt_vnodecovered; + vput(tdp); + VREF(dp); + vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); + } + } + + /* + * We now have a segment name to search for, and a directory to search. + */ +unionlookup: + ndp->ni_dvp = dp; + ndp->ni_vp = NULL; + cnp->cn_flags &= ~PDIRUNLOCK; + ASSERT_VOP_LOCKED(dp, "lookup"); + if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) { + KASSERT(ndp->ni_vp == NULL, ("leaf should be empty")); +#ifdef NAMEI_DIAGNOSTIC + printf("not found\n"); +#endif + if ((error == ENOENT) && + (dp->v_flag & VROOT) && (dp->v_mount != NULL) && + (dp->v_mount->mnt_flag & MNT_UNION)) { + tdp = dp; + dp = dp->v_mount->mnt_vnodecovered; + if (cnp->cn_flags & PDIRUNLOCK) + vrele(tdp); + else + vput(tdp); + VREF(dp); + vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); + goto unionlookup; + } + + if (error != EJUSTRETURN) + goto bad; + /* + * If creating and at end of pathname, then can consider + * allowing file to be created. + */ + if (rdonly) { + error = EROFS; + goto bad; + } + if (*cp == '\0' && trailing_slash && + !(cnp->cn_flags & WILLBEDIR)) { + error = ENOENT; + goto bad; + } + /* + * 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. + */ + if (cnp->cn_flags & SAVESTART) { + ndp->ni_startdir = ndp->ni_dvp; + VREF(ndp->ni_startdir); + } + return (0); + } +#ifdef NAMEI_DIAGNOSTIC + printf("found\n"); +#endif + + ASSERT_VOP_LOCKED(ndp->ni_vp, "lookup"); + + /* + * Take into account any additional components consumed by + * the underlying filesystem. + */ + if (cnp->cn_consume > 0) { + cnp->cn_nameptr += cnp->cn_consume; + ndp->ni_next += cnp->cn_consume; + ndp->ni_pathlen -= cnp->cn_consume; + cnp->cn_consume = 0; + } + + dp = ndp->ni_vp; + + /* + * Check to see if the vnode has been mounted on; + * if so find the root of the mounted filesystem. + */ + while (dp->v_type == VDIR && (mp = dp->v_mountedhere) && + (cnp->cn_flags & NOCROSSMOUNT) == 0) { + if (vfs_busy(mp, 0, 0, td)) + continue; + VOP_UNLOCK(dp, 0, td); + error = VFS_ROOT(mp, &tdp); + vfs_unbusy(mp, td); + if (error) { + dpunlocked = 1; + goto bad2; + } + vrele(dp); + ndp->ni_vp = dp = tdp; + } + + /* + * Check for symbolic link + */ + if ((dp->v_type == VLNK) && + ((cnp->cn_flags & FOLLOW) || trailing_slash || + *ndp->ni_next == '/')) { + cnp->cn_flags |= ISSYMLINK; + if (dp->v_mount == NULL) { + /* We can't know whether the directory was mounted with + * NOSYMFOLLOW, so we can't follow safely. */ + error = EBADF; + goto bad2; + } + if (dp->v_mount->mnt_flag & MNT_NOSYMFOLLOW) { + error = EACCES; + goto bad2; + } + return (0); + } + + /* + * Check for bogus trailing slashes. + */ + if (trailing_slash && dp->v_type != VDIR) { + error = ENOTDIR; + goto bad2; + } + +nextname: + /* + * Not a symbolic link. If more pathname, + * continue at next component, else return. + */ + if (*ndp->ni_next == '/') { + cnp->cn_nameptr = ndp->ni_next; + while (*cnp->cn_nameptr == '/') { + cnp->cn_nameptr++; + ndp->ni_pathlen--; + } + if (ndp->ni_dvp != ndp->ni_vp) + ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "lookup"); + vrele(ndp->ni_dvp); + goto dirloop; + } + /* + * Disallow directory write attempts on read-only filesystems. + */ + if (rdonly && + (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { + error = EROFS; + goto bad2; + } + if (cnp->cn_flags & SAVESTART) { + ndp->ni_startdir = ndp->ni_dvp; + VREF(ndp->ni_startdir); + } + if (!wantparent) + vrele(ndp->ni_dvp); + + if ((cnp->cn_flags & LOCKLEAF) == 0) + VOP_UNLOCK(dp, 0, td); + return (0); + +bad2: + if ((cnp->cn_flags & (LOCKPARENT | PDIRUNLOCK)) == LOCKPARENT && + *ndp->ni_next == '\0') + VOP_UNLOCK(ndp->ni_dvp, 0, td); + vrele(ndp->ni_dvp); +bad: + if (dpunlocked) + vrele(dp); + else + vput(dp); + ndp->ni_vp = NULL; + 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; +{ + struct thread *td = cnp->cn_thread; + 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; + vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td); + +/* dirloop: */ + /* + * Search a new directory. + * + * 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 + 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, 0, td); + *vpp = dp; + /* XXX This should probably move to the top of function. */ + 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. + */ + if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) { + KASSERT(*vpp == NULL, ("leaf should be empty")); + if (error != EJUSTRETURN) + goto bad; + /* + * If creating and at end of pathname, then can consider + * allowing file to be created. + */ + if (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; + + /* + * Check for symbolic link + */ + KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW), + ("relookup: symlink found.\n")); + + /* + * Disallow directory write attempts on read-only filesystems. + */ + if (rdonly && + (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) { + error = EROFS; + goto bad2; + } + /* ASSERT(dvp == ndp->ni_startdir) */ + if (cnp->cn_flags & SAVESTART) + VREF(dvp); + + if (!wantparent) + vrele(dvp); + + if (vn_canvmio(dp) == TRUE && + ((cnp->cn_flags & (NOOBJ|LOCKLEAF)) == LOCKLEAF)) + vfs_object_create(dp, td, cnp->cn_cred); + + if ((cnp->cn_flags & LOCKLEAF) == 0) + VOP_UNLOCK(dp, 0, td); + return (0); + +bad2: + if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN)) + VOP_UNLOCK(dvp, 0, td); + vrele(dvp); +bad: + vput(dp); + *vpp = NULL; + return (error); +} |
