+
+/*
+ * 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 proc *p = cnp->cn_proc;
+ 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, p);
+
+/* 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, 0, p);
+ *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.
+ */
+ if (error = VOP_LOOKUP(dp, vpp, cnp)) {
+#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) {
+ 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
+
+ /*
+ * Disallow directory write attempts on read-only file systems.
+ */
+ 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 ((cnp->cn_flags & LOCKLEAF) == 0)
+ VOP_UNLOCK(dp, 0, p);
+ return (0);
+
+bad2:
+ if ((cnp->cn_flags & LOCKPARENT) && (cnp->cn_flags & ISLASTCN))
+ VOP_UNLOCK(dvp, 0, p);
+ vrele(dvp);
+bad:
+ vput(dp);
+ *vpp = NULL;
+ return (error);
+}
projects / unix-history / blobdiff