recovery: install packages in a known mount environment

When installing a package, we should have /tmp and /cache mounted and
nothing else.  Ensure this is true by explicitly mounting them and
unmounting everything else as the first step of every install.

Also fix an error in the progress bar that crops up when you do
multiple package installs in one instance of recovery.

Change-Id: I4837ed707cb419ddd3d9f6188b6355ba1bcfe2b2

1 files changed, 19 insertions, 0 deletions

diff --git a/roots.cpp b/roots.cpp
index 0947122..113dba1 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -202,3 +202,22 @@ int format_volume(const char* volume) {
     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;
+}