installd: Delete cache properly for devices using datadata partition

The java side already checks /data/data for free space but installd
still checks /data causing it to never reap the cache (because it
thinks that enough free space is available.)

Change-Id: I191f3ceb84df1101ab2918ec0038213d72ec1ce2

cmds/installd/commands.c

@@ -19,6 +19,7 @@
 
 /* Directory records that are used in execution of commands. */
 dir_rec_t android_data_dir;
+dir_rec_t android_datadata_dir;
 dir_rec_t android_asec_dir;
 dir_rec_t android_app_dir;
 dir_rec_t android_app_private_dir;
@@ -162,7 +163,11 @@ int delete_cache(const char *pkgname)
 static int64_t disk_free()
 {
     struct statfs sfs;
-    if (statfs(android_data_dir.path, &sfs) == 0) {
+    /* Scanning /data/data because on some devices, it's on a different partition
+     * and scanning /data will yield the incorrect result. (This function is only
+     * used for freeing space on /data/data so it is okay to be more specific.)
+     */
+    if (statfs(android_datadata_dir.path, &sfs) == 0) {
         return sfs.f_bavail * sfs.f_bsize;
     } else {
         LOGE("Couldn't statfs %s: %s\n", android_data_dir.path, strerror(errno));

cmds/installd/installd.c

@@ -270,6 +270,11 @@ int initialize_globals() {
         return -1;
     }
 
+    // Get the android datadata directory.
+    if (copy_and_append(&android_datadata_dir, &android_data_dir, DATA_SUBDIR) < 0) {
+        return -1;
+    }
+
     // Get the android app directory.
     if (copy_and_append(&android_app_dir, &android_data_dir, APP_SUBDIR) < 0) {
         return -1;

cmds/installd/installd.h

@@ -58,6 +58,7 @@
 
 #define CACHE_DIR_POSTFIX      "/cache"
 
+#define DATA_SUBDIR             "data/" // sub-directory under ANDROID_DATA
 #define APP_SUBDIR             "app/" // sub-directory under ANDROID_DATA
 
 /* other handy constants */
@@ -87,6 +88,7 @@ typedef struct {
 extern dir_rec_t android_app_dir;
 extern dir_rec_t android_app_private_dir;
 extern dir_rec_t android_data_dir;
+extern dir_rec_t android_datadata_dir;
 extern dir_rec_t android_asec_dir;
 extern dir_rec_array_t android_system_dirs;