VOP_RENAME(9)

NAME
VOP_RENAME - rename a file

SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
int
VOP_RENAME(struct vnode *fdvp, struct vnode *fvp, struct componentname *fcnp, struct vnode *tdvp, struct vnode *tvp, struct componentname *tcnp);

DESCRIPTION
This renames a file and possibly changes its parent directory. If the destination object exists, it will be removed first.

Its arguments are:

fdvp
    the vnode of the old parent directory

fvp the vnode of the file to be renamed

fcnp
    pathname information about the file's current name

tdvp
    the vnode of the new parent directory

tvp the vnode of the target file (if it exists)

tcnp
    pathname information about the file's new name

LOCKS
The destination directory and file (if it exists) should be locked on entry. The source directory and file will be released on exit. The destination directory and file (if it exists) will be unlocked and released on exit.

PSEUDOCODE

    int
    vop_rename(struct vnode *fdvp, struct vnode *fvp, struct componentname *fcnp,
    	   struct vnode *tdvp, struct vnode *tvp, struct componentname *tcnp)
    {
        int doingdirectory = 0;
        int error = 0;
        /*
         * Check for cross-device rename.
         */
        if (fvp->v_mount != tdvp->v_mount) {
    	error = EXDEV;
        abortit:
    	VOP_ABORTOP(tdvp, tcnp);
    	if (tdvp == tvp)
    	    vrele(tdvp);
    	else
    	    vput(tdvp);
    	if (tvp)
    	    vput(tvp);
    	VOP_ABORTOP(fdvp, fcnp);
    	vrele(fdvp);
    	vrele(fvp);
    	return error;
        }
        if (tvp exists and is immutable) {
    	error = EPERM;
    	goto abortit;
        }
        /*
         * Check if just deleting a link name.
         */
        if (fvp == tvp) {
    	if (fvp->v_type == VDIR) {
    	    error = EINVAL;
    	    goto abortit;
    	}
    	/*
    	 * Release destination.
    	 */
    	VOP_ABORTOP(tdvp, tcnp);
    	vput(tdvp);
    	vput(tvp);
    	/*
    	 * Delete source.  Pretty bizarre stuff.
    	 */
    	vrele(fdvp);
    	vrele(fvp);
    	fcnp->cn_flags &= ~MODMASK;
    	fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
    	fcnp->cn_nameiop = DELETE;
    	VREF(fdvp);
    	error = relookup(fdvp, &fvp, fcnp);
    	if (error == 0)
    	    vrele(fdvp);
    	return VOP_REMOVE(fdvp, fvp, fcnp);
        }
        if (fvp is immutable) {
    	error = EPERM;
    	goto abortit;
        }
        error = VOP_LOCK(fvp);
        if (error)
    	goto abortit;
        if (vp is a directory) {
    	/*
    	 * Avoid ".", "..", and aliases of "." for obvious reasons.
    	 */
    	if ((fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.')
    	    || fdvp == fvp
    	    || ((fcnp->cn_flags | tcnp->cn_flags) & ISDOTDOT)) {
    	    VOP_UNLOCK(fvp);
    	    error = EINVAL;
    	    goto abortit;
    	}
    	doingdirectory = 1;
        }
        vrele(fdvp);
        /*
         * Bump link count on fvp while we are moving stuff around.  If we
         * crash before completing the work, the link count may be wrong
         * but correctable.
         */
        ...;
        /*
         * If ".." must be changed (ie the directory gets a new
         * parent) then the source directory must not be in the
         * directory hierarchy above the target, as this would
         * orphan everything below the source directory. Also
         * the user must have write permission in the source so
         * as to be able to change "..".
         */
        error = VOP_ACCESS(fvp, VWRITE, tcnp->cn_cred, tcnp->cn_proc);
        VOP_UNLOCK(fvp);
        if (doingdirectory && fdvp != tdvp) {
    	/*
    	 * Check for pathname conflict.
    	 */
    	...;
        }
        /*
         * If the target doesn't exist, link the target to the source and
         * unlink the source.  Otherwise, rewrite the target directory to
         * reference the source and remove the original entry.
         */
        if (tvp == NULL) {
    	/*
    	 * Account for ".." in new directory.
    	 */
    	if (doingdirectory && fdvp != tdvp) {
    	    /*
    	     * Increase link count of tdvp.
    	     */
    	    ...;
    	}

    	/*
    	 * Add name in new directory.
    	 */
    	...;
    	if (error) {
    	    if (doingdirectory && fdvp != tdvp) {
    		/*
    		 * Decrease link count if tdvp.
    		 */
    		...;
    	    }
    	    goto bad;
    	}
    	vput(tdvp);
        } else {
    	/*
    	 * Target must be empty if a directory and have no links
    	 * to it. Also, ensure source and target are compatible
    	 * (both directories, or both not directories).
    	 */
    	if (tvp is a directory) {
    	    if (tvp is not empty) {
    		error = ENOTEMPTY;
    		goto bad;
    	    }
    	    if (!doingdirectory) {
    		error = ENOTDIR;
    		goto bad;
    	    }
    	    /*
    	     * Update name cache since directory is going away.
    	     */
    	    cache_purge(tdvp);
    	} else if (doingdirectory) {
    	    error = ENOTDIR;
    	    goto bad;
    	}
    	/*
    	 * Change name tcnp in tdvp to point at fvp.
    	 */
    	...;
    	/*
    	 * If the target directory is in same directory as the source
    	 * directory, decrement the link count on the parent of the
    	 * target directory.  This accounts for the fact that a
    	 * directory links back to its parent with "..".
    	 */
    	if (doingdirectory && fdvp == tdvp) {
    	    /*
    	     * Decrement link count of tdvp.
    	     */
    	    ...;
    	}
    	vput(tdvp);
    	/*
    	 * Decrement the link count of tvp since the directory no
    	 * longer points at it.
    	 */
    	...;
    	if (doingdirectory) {
    	    /*
    	     * Clean up the old directory tvp.
    	     */
    	    ...;
    	}
    	vput(tvp);
        }
        /*
         * Unlink the source.  If a directory was moved to a new parent,
         * update its ".." entry.  Gobs of ugly UFS code omitted here.
         */
        ...;
    bad:
        if (tvp)
    	vput(tvp);
        vput(tdvp);
    out:
        if (VOP_LOCK(fvp) == 0) {
    	/*
    	 * Decrement link count of fvp.
    	 */
    	...;
            vput(fvp);
        } else
    	vrele(fvp);
        return error;
    }

ERRORS

[EPERM]
    the file is immutable

[EXDEV]
    cross device move

[EINVAL]
    illegal directory rename

[ENOTDIR]
    attempt to rename a directory to a file or vice versa

[ENOTEMPTY]
    attempt to remove a directory which is not empty

SEE ALSO
vnode(9)

AUTHORS
This man page was written by Doug Rabson.