Handle multi-user mountObb() requests.

Since emulated external storage paths differ based on execution
context, carefully fix up paths for various use-cases:

1. When sending paths to DefaultContainerService, always scope
   OBB paths as belonging to USER_OWNER.
2. When sending paths to vold, always build emulated storage paths
   visible to root.
3. Always use the original untouched path when talking with apps.

Mount OBB containers using shared app GID, so that an app can read
the mount point across users.

Handle legacy paths like "/sdcard" by resolving the canonical path
before sending to MountService.  Move tests to servicestests, and
add tests for new path generation logic.

Bug: 7212801
Change-Id: I078c52879cd08d9c8a52cc8c83ac7ced1e8035e7

1 files changed, 12 insertions, 3 deletions

diff --git a/native/android/storage_manager.cpp b/native/android/storage_manager.cpp
index f2f36b62..399f1ff 100644
--- a/native/android/storage_manager.cpp
+++ b/native/android/storage_manager.cpp
@@ -125,11 +125,20 @@ public:
         }
     }
 
-    void mountObb(const char* filename, const char* key, AStorageManager_obbCallbackFunc func, void* data) {
+    void mountObb(const char* rawPath, const char* key, AStorageManager_obbCallbackFunc func,
+            void* data) {
+        // Resolve path before sending to MountService
+        char canonicalPath[PATH_MAX];
+        if (realpath(rawPath, canonicalPath) == NULL) {
+            ALOGE("mountObb failed to resolve path %s: %s", rawPath, strerror(errno));
+            return;
+        }
+
         ObbCallback* cb = registerObbCallback(func, data);
-        String16 filename16(filename);
+        String16 rawPath16(rawPath);
+        String16 canonicalPath16(canonicalPath);
         String16 key16(key);
-        mMountService->mountObb(filename16, key16, mObbActionListener, cb->nonce);
+        mMountService->mountObb(rawPath16, canonicalPath16, key16, mObbActionListener, cb->nonce);
     }
 
     void unmountObb(const char* filename, const bool force, AStorageManager_obbCallbackFunc func, void* data) {