diff --git a/roots.cpp b/roots.cpp
index 0947122..113dba1 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -202,3 +202,22 @@
     LOGE("format_volume: fs_type \"%s\" unsupported\n", v->fs_type);
     return -1;
 }
+
+int setup_install_mounts() {
+    if (fstab == NULL) {
+        LOGE("can't set up install mounts: no fstab loaded\n");
+        return -1;
+    }
+    for (int i = 0; i < fstab->num_entries; ++i) {
+        Volume* v = fstab->recs + i;
+
+        if (strcmp(v->mount_point, "/tmp") == 0 ||
+            strcmp(v->mount_point, "/cache") == 0) {
+            if (ensure_path_mounted(v->mount_point) != 0) return -1;
+
+        } else {
+            if (ensure_path_unmounted(v->mount_point) != 0) return -1;
+        }
+    }
+    return 0;
+}