+/*!
+ * @brief symlink safe chdir replacement
+ *
+ * Only chdirs to dir if it doesn't contain symlinks.
+ *
+ * @returns 1 if a path element is a symlink, 0 otherwise, -1 on syserror
+ */
+static int lchdir(const char *dir)
+{
+ int ret = 0;
+ char buf[MAXPATHLEN+1];
+#ifdef REALPATH_TAKES_NULL
+ char *rpath = NULL;
+#else
+ char rpath[MAXPATHLEN+1];
+#endif
+
+ /* dir might be an relative or an absolute path */
+ if (dir[0] == '/') {
+ /* absolute path, just make sure buf is prepared for strlcat */
+ buf[0] = 0;
+ } else {
+ /* relative path, push cwd int buf */
+ if (getcwd(buf, MAXPATHLEN) == NULL)
+ return -1;
+ if (strlcat(buf, "/", MAXPATHLEN) >= MAXPATHLEN)
+ return -1;
+ }
+
+ if (strlcat(buf, dir, MAXPATHLEN) >= MAXPATHLEN)
+ return -1;
+
+#ifdef REALPATH_TAKES_NULL
+ if ((rpath = realpath(dir, NULL)) == NULL) {
+#else
+ if (realpath(dir, rpath) == NULL) {
+#endif
+ ret = -1;
+ goto exit;
+ }
+
+ /*
+ * Cases:
+ * chdir request | realpath result | ret
+ * (after getwcwd) | |
+ * =======================================
+ * /a/b/. | /a/b | 0
+ * /a/b/. | /c | 1
+ * /a/b/. | /c/d/e/f | 1
+ */
+ ret = 0;
+ for (int i = 0; rpath[i]; i++) {
+ if (buf[i] != rpath[i]) {
+ ret = 1;
+ goto exit;
+ }
+ }
+
+ if (chdir(dir) != 0) {
+ ret = -1;
+ goto exit;
+ }
+
+exit:
+#ifdef REALPATH_TAKES_NULL
+ free(rpath);
+#endif
+ return ret;
+}
+
+static struct dir *
+vol_tree_root(const struct vol *vol, u_int32_t did)
+{
+ struct dir *dir;
+
+ if (vol->v_curdir && vol->v_curdir->d_did == did) {
+ dir = vol->v_curdir;
+ }
+ else {
+ dir = vol->v_root;
+ }
+ return dir;
+}
+