+
+/*
+ * copyfile. copy the vnode (fvp) to the vnode (tvp)
+ * using a sequence of reads and writes. both (fvp)
+ * and (tvp) are locked on entry and exit.
+ */
+int
+union_copyfile(p, cred, fvp, tvp)
+ struct proc *p;
+ struct ucred *cred;
+ struct vnode *fvp;
+ struct vnode *tvp;
+{
+ char *buf;
+ struct uio uio;
+ struct iovec iov;
+ int error = 0;
+
+ /*
+ * strategy:
+ * allocate a buffer of size MAXBSIZE.
+ * loop doing reads and writes, keeping track
+ * of the current uio offset.
+ * give up at the first sign of trouble.
+ */
+
+ uio.uio_procp = p;
+ uio.uio_segflg = UIO_SYSSPACE;
+ uio.uio_offset = 0;
+
+ VOP_UNLOCK(fvp); /* XXX */
+ LEASE_CHECK(fvp, p, cred, LEASE_READ);
+ VOP_LOCK(fvp); /* XXX */
+ VOP_UNLOCK(tvp); /* XXX */
+ LEASE_CHECK(tvp, p, cred, LEASE_WRITE);
+ VOP_LOCK(tvp); /* XXX */
+
+ buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK);
+
+ /* ugly loop follows... */
+ do {
+ off_t offset = uio.uio_offset;
+
+ uio.uio_iov = &iov;
+ uio.uio_iovcnt = 1;
+ iov.iov_base = buf;
+ iov.iov_len = MAXBSIZE;
+ uio.uio_resid = iov.iov_len;
+ uio.uio_rw = UIO_READ;
+ error = VOP_READ(fvp, &uio, 0, cred);
+
+ if (error == 0) {
+ uio.uio_iov = &iov;
+ uio.uio_iovcnt = 1;
+ iov.iov_base = buf;
+ iov.iov_len = MAXBSIZE - uio.uio_resid;
+ uio.uio_offset = offset;
+ uio.uio_rw = UIO_WRITE;
+ uio.uio_resid = iov.iov_len;
+
+ if (uio.uio_resid == 0)
+ break;
+
+ do {
+ error = VOP_WRITE(tvp, &uio, 0, cred);
+ } while ((uio.uio_resid > 0) && (error == 0));
+ }
+
+ } while (error == 0);
+
+ free(buf, M_TEMP);
+ return (error);
+}
+
+/*
+ * union_vn_create: creates and opens a new shadow file
+ * on the upper union layer. this function is similar
+ * in spirit to calling vn_open but it avoids calling namei().
+ * the problem with calling namei is that a) it locks too many
+ * things, and b) it doesn't start at the "right" directory,
+ * whereas relookup is told where to start.
+ */
+int
+union_vn_create(vpp, un, cmode, p)
+ struct vnode **vpp;
+ struct union_node *un;
+ int cmode;
+ struct proc *p;
+{
+ struct vnode *vp;
+ struct ucred *cred = p->p_ucred;
+ struct vattr vat;
+ struct vattr *vap = &vat;
+ int fmode = FFLAGS(O_WRONLY|O_CREAT|O_TRUNC|O_EXCL);
+ int error;
+ int hash;
+ char *cp;
+ struct componentname cn;
+
+ *vpp = NULLVP;
+
+ cn.cn_namelen = strlen(un->un_path);
+ cn.cn_pnbuf = (caddr_t) malloc(cn.cn_namelen, M_NAMEI, M_WAITOK);
+ bcopy(un->un_path, cn.cn_pnbuf, cn.cn_namelen+1);
+ cn.cn_nameiop = CREATE;
+ cn.cn_flags = (LOCKLEAF|LOCKPARENT|HASBUF|SAVENAME|ISLASTCN);
+ cn.cn_proc = p;
+ cn.cn_cred = p->p_ucred;
+ cn.cn_nameptr = cn.cn_pnbuf;
+ for (hash = 0, cp = cn.cn_nameptr; *cp != 0 && *cp != '/'; cp++)
+ hash += (unsigned char)*cp;
+ cn.cn_hash = hash;
+ cn.cn_consume = 0;
+
+ if (error = relookup(un->un_dirvp, &vp, &cn))
+ return (error);
+ if (vp == NULLVP) {
+ VATTR_NULL(vap);
+ vap->va_type = VREG;
+ vap->va_mode = cmode;
+ LEASE_CHECK(un->un_dirvp, p, cred, LEASE_WRITE);
+ if (error = VOP_CREATE(un->un_dirvp, &vp,
+ &cn, vap))
+ return (error);
+ } else {
+ VOP_ABORTOP(un->un_dirvp, &cn);
+ if (un->un_dirvp == vp)
+ vrele(un->un_dirvp);
+ else
+ vput(vp);
+ error = EEXIST;
+ goto bad;
+ }
+
+ if (vp->v_type != VREG) {
+ error = EOPNOTSUPP;
+ goto bad;
+ }
+
+ VOP_UNLOCK(vp); /* XXX */
+ LEASE_CHECK(vp, p, cred, LEASE_WRITE);
+ VOP_LOCK(vp); /* XXX */
+ VATTR_NULL(vap);
+ vap->va_size = 0;
+ if (error = VOP_SETATTR(vp, vap, cred, p))
+ goto bad;
+
+ if (error = VOP_OPEN(vp, fmode, cred, p))
+ goto bad;
+
+ vp->v_writecount++;
+ *vpp = vp;
+ return (0);
+bad:
+ vput(vp);
+ return (error);
+}
projects / unix-history / commitdiff