- fp = getinode(uap->fd);
- if (fp == NULL)
- return;
- ip = (struct inode *)fp->f_data;
- ilock(ip);
- syncip(ip);
- iunlock(ip);
-}
-
-/*
- * Rename system call.
- * rename("foo", "bar");
- * is essentially
- * unlink("bar");
- * link("foo", "bar");
- * unlink("foo");
- * but ``atomically''. Can't do full commit without saving state in the
- * inode on disk which isn't feasible at this time. Best we can do is
- * always guarantee the target exists.
- *
- * Basic algorithm is:
- *
- * 1) Bump link count on source while we're linking it to the
- * target. This also insure the inode won't be deleted out
- * from underneath us while we work.
- * 2) Link source to destination. If destination already exists,
- * delete it first.
- * 3) Unlink source reference to inode if still around.
- * 4) If a directory was moved and the parent of the destination
- * is different from the source, patch the ".." entry in the
- * directory.
- *
- * Source and destination must either both be directories, or both
- * not be directories. If target is a directory, it must be empty.
- */
-rename()
-{
- struct a {
- char *from;
- char *to;
- } *uap;
- register struct inode *ip, *xp, *dp;
- int oldparent, parentdifferent, doingdirectory;
- int error = 0;
-
- uap = (struct a *)u.u_ap;
- ip = namei(uchar, DELETE | LOCKPARENT, 0);
- if (ip == NULL)
- return;
- dp = u.u_pdir;
- oldparent = 0, doingdirectory = 0;
- if ((ip->i_mode&IFMT) == IFDIR) {
- register struct direct *d;
-
- d = &u.u_dent;
- /*
- * Avoid ".", "..", and aliases of "." for obvious reasons.
- */
- if ((d->d_namlen == 1 && d->d_name[0] == '.') ||
- (d->d_namlen == 2 && bcmp(d->d_name, "..", 2) == 0) ||
- (dp == ip)) {
- iput(dp);
- if (dp == ip)
- irele(ip);
- else
- iput(ip);
- u.u_error = EINVAL;
- return;
- }
- oldparent = dp->i_number;
- doingdirectory++;
- }
- iput(dp);
-
- /*
- * 1) Bump link count while we're moving stuff
- * around. If we crash somewhere before
- * completing our work, the link count
- * may be wrong, but correctable.
- */
- ip->i_nlink++;
- ip->i_flag |= ICHG;
- iupdat(ip, &time, &time, 1);
- iunlock(ip);
-
- /*
- * When the target exists, both the directory
- * and target inodes are returned locked.
- */
- u.u_dirp = (caddr_t)uap->to;
- xp = namei(uchar, CREATE | LOCKPARENT | NOCACHE, 0);
- if (u.u_error) {
- error = u.u_error;
- goto out;
- }
- dp = u.u_pdir;
- /*
- * If ".." must be changed (ie the directory gets a new
- * parent) then the source directory must not be in the
- * directory heirarchy 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 "..". We must repeat the call
- * to namei, as the parent directory is unlocked by the
- * call to checkpath().
- */
- parentdifferent = oldparent != dp->i_number;
- if (doingdirectory && parentdifferent) {
- if (access(ip, IWRITE))
- goto bad;
- do {
- dp = u.u_pdir;
- if (xp != NULL)
- iput(xp);
- u.u_error = checkpath(ip, dp);
- if (u.u_error)
- goto out;
- u.u_dirp = (caddr_t)uap->to;
- xp = namei(uchar, CREATE | LOCKPARENT | NOCACHE, 0);
- if (u.u_error) {
- error = u.u_error;
- goto out;
- }
- } while (dp != u.u_pdir);
- }
- /*
- * 2) If target doesn't exist, link the target
- * to the source and unlink the source.
- * Otherwise, rewrite the target directory
- * entry to reference the source inode and
- * expunge the original entry's existence.
- */
- if (xp == NULL) {
- if (dp->i_dev != ip->i_dev) {
- error = EXDEV;
- goto bad;
- }
- /*
- * Account for ".." in directory.
- * When source and destination have the
- * same parent we don't fool with the
- * link count -- this isn't required
- * because we do a similar check below.
- */
- if (doingdirectory && parentdifferent) {
- dp->i_nlink++;
- dp->i_flag |= ICHG;
- iupdat(dp, &time, &time, 1);
- }
- error = direnter(ip);
- if (error)
- goto out;
- } else {
- if (xp->i_dev != dp->i_dev || xp->i_dev != ip->i_dev) {
- error = EXDEV;
- goto bad;
- }
- /*
- * Short circuit rename(foo, foo).
- */
- if (xp->i_number == ip->i_number)
- goto bad;
- /*
- * Target must be empty if a directory
- * and have no links to it.
- * Also, insure source and target are
- * compatible (both directories, or both
- * not directories).
- */
- if ((xp->i_mode&IFMT) == IFDIR) {
- if (!dirempty(xp) || xp->i_nlink > 2) {
- error = ENOTEMPTY;
- goto bad;
- }
- if (!doingdirectory) {
- error = ENOTDIR;
- goto bad;
- }
- } else if (doingdirectory) {
- error = EISDIR;
- goto bad;
- }
- dirrewrite(dp, ip);
- if (u.u_error) {
- error = u.u_error;
- goto bad1;
- }
- /*
- * Adjust the link count of the target to
- * reflect the dirrewrite above. If this is
- * a directory it is empty and there are
- * no links to it, so we can squash the inode and
- * any space associated with it. We disallowed
- * renaming over top of a directory with links to
- * it above, as we've no way to determine if
- * we've got a link or the directory itself, and
- * if we get a link, then ".." will be screwed up.
- */
- xp->i_nlink--;
- if (doingdirectory) {
- if (--xp->i_nlink != 0)
- panic("rename: linked directory");
- itrunc(xp, (u_long)0);
- }
- xp->i_flag |= ICHG;
- iput(xp);
- xp = NULL;
- }
-
- /*
- * 3) Unlink the source.
- */
- u.u_dirp = uap->from;
- dp = namei(uchar, DELETE, 0);
- /*
- * Insure directory entry still exists and
- * has not changed since the start of all
- * this. If either has occured, forget about
- * about deleting the original entry and just
- * adjust the link count in the inode.
- */
- if (dp == NULL || u.u_dent.d_ino != ip->i_number) {
- ip->i_nlink--;