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Commit c31097da authored by Sudheer Shanka's avatar Sudheer Shanka
Browse files

Refactor MountEmulatedStorage(). 

Test: atest cts/hostsidetests/appsecurity/src/android/appsecurity/cts/ExternalStorageHostTest.java
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: I3938921033bc407e28548749f9d6f8ba040333d2
parent c7c2ddec

core/jni/com_android_internal_os_Zygote.cpp

+41 −29
Original line number Original line Diff line number Diff line
@@ -292,6 +292,7 @@ static std::array<UsapTableEntry, USAP_POOL_SIZE_MAX_LIMIT> gUsapTable; 
static FileDescriptorTable* gOpenFdTable = nullptr;

static FileDescriptorTable* gOpenFdTable = nullptr;





// Must match values in com.android.internal.os.Zygote.

// Must match values in com.android.internal.os.Zygote.

// The order of entries here must be kept in sync with ExternalStorageViews array values.

enum MountExternalKind {

enum MountExternalKind {

  MOUNT_EXTERNAL_NONE = 0,

  MOUNT_EXTERNAL_NONE = 0,

  MOUNT_EXTERNAL_DEFAULT = 1,

  MOUNT_EXTERNAL_DEFAULT = 1,
@@ -300,6 +301,18 @@ enum MountExternalKind { 
  MOUNT_EXTERNAL_LEGACY = 4,

  MOUNT_EXTERNAL_LEGACY = 4,

  MOUNT_EXTERNAL_INSTALLER = 5,

  MOUNT_EXTERNAL_INSTALLER = 5,

  MOUNT_EXTERNAL_FULL = 6,

  MOUNT_EXTERNAL_FULL = 6,

  MOUNT_EXTERNAL_COUNT = 7

};



// The order of entries here must be kept in sync with MountExternalKind enum values.

static const std::array<const std::string, MOUNT_EXTERNAL_COUNT> ExternalStorageViews = {

  "",                     // MOUNT_EXTERNAL_NONE

  "/mnt/runtime/default", // MOUNT_EXTERNAL_DEFAULT

  "/mnt/runtime/read",    // MOUNT_EXTERNAL_READ

  "/mnt/runtime/write",   // MOUNT_EXTERNAL_WRITE

  "/mnt/runtime/write",   // MOUNT_EXTERNAL_LEGACY

  "/mnt/runtime/write",   // MOUNT_EXTERNAL_INSTALLER

  "/mnt/runtime/full",    // MOUNT_EXTERNAL_FULL

};

};





// Must match values in com.android.internal.os.Zygote.

// Must match values in com.android.internal.os.Zygote.
@@ -633,6 +646,23 @@ static int UnmountTree(const char* path) { 
  return 0;

  return 0;

}

}





static void CreateDir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid,

                      fail_fn_t fail_fn) {

  if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) {

    fail_fn(CREATE_ERROR("fs_prepare_dir failed on %s: %s",

                         dir.c_str(), strerror(errno)));

  }

}



static void BindMount(const std::string& source_dir, const std::string& target_dir,

                      fail_fn_t fail_fn) {

  if (TEMP_FAILURE_RETRY(mount(source_dir.c_str(), target_dir.c_str(), nullptr,

                               MS_BIND | MS_REC, nullptr)) == -1) {

    fail_fn(CREATE_ERROR("Failed to mount %s to %s: %s",

                         source_dir.c_str(), target_dir.c_str(), strerror(errno)));

  }

}



// Create a private mount namespace and bind mount appropriate emulated

// Create a private mount namespace and bind mount appropriate emulated

// storage for the given user.

// storage for the given user.

static void MountEmulatedStorage(uid_t uid, jint mount_mode,

static void MountEmulatedStorage(uid_t uid, jint mount_mode,
@@ -641,18 +671,11 @@ static void MountEmulatedStorage(uid_t uid, jint mount_mode, 
  // See storage config details at http://source.android.com/tech/storage/

  // See storage config details at http://source.android.com/tech/storage/

  ATRACE_CALL();

  ATRACE_CALL();





  String8 storage_source;

  if (mount_mode < 0 || mount_mode >= MOUNT_EXTERNAL_COUNT) {

  if (mount_mode == MOUNT_EXTERNAL_DEFAULT) {

    fail_fn(CREATE_ERROR("Unknown mount_mode: %d", mount_mode));

    storage_source = "/mnt/runtime/default";

  }

  } else if (mount_mode == MOUNT_EXTERNAL_READ) {



    storage_source = "/mnt/runtime/read";

  if (mount_mode == MOUNT_EXTERNAL_NONE && !force_mount_namespace) {

  } else if (mount_mode == MOUNT_EXTERNAL_WRITE

      || mount_mode == MOUNT_EXTERNAL_LEGACY

      || mount_mode == MOUNT_EXTERNAL_INSTALLER) {

    storage_source = "/mnt/runtime/write";

  } else if (mount_mode == MOUNT_EXTERNAL_FULL) {

    storage_source = "/mnt/runtime/full";

  } else if (mount_mode == MOUNT_EXTERNAL_NONE && !force_mount_namespace) {

    // Sane default of no storage visible

    // Sane default of no storage visible

    return;

    return;

  }

  }
@@ -667,26 +690,15 @@ static void MountEmulatedStorage(uid_t uid, jint mount_mode, 
    return;

    return;

  }

  }





  if (TEMP_FAILURE_RETRY(mount(storage_source.string(), "/storage", nullptr,

  const std::string& storage_source = ExternalStorageViews[mount_mode];

                               MS_BIND | MS_REC | MS_SLAVE, nullptr)) == -1) {



    fail_fn(CREATE_ERROR("Failed to mount %s to /storage: %s",

  BindMount(storage_source, "/storage", fail_fn);

                         storage_source.string(),

                         strerror(errno)));

  }





  // Mount user-specific symlink helper into place

  // Mount user-specific symlink helper into place

  userid_t user_id = multiuser_get_user_id(uid);

  userid_t user_id = multiuser_get_user_id(uid);

  const String8 user_source(String8::format("/mnt/user/%d", user_id));

  const std::string user_source = StringPrintf("/mnt/user/%d", user_id);

  if (fs_prepare_dir(user_source.string(), 0751, 0, 0) == -1) {

  CreateDir(user_source, 0751, AID_ROOT, AID_ROOT, fail_fn);

    fail_fn(CREATE_ERROR("fs_prepare_dir failed on %s",

  BindMount(user_source, "/storage/self", fail_fn);

                         user_source.string()));

  }



  if (TEMP_FAILURE_RETRY(mount(user_source.string(), "/storage/self",

                               nullptr, MS_BIND, nullptr)) == -1) {

    fail_fn(CREATE_ERROR("Failed to mount %s to /storage/self: %s",

                         user_source.string(), strerror(errno)));

  }

}

}





static bool NeedsNoRandomizeWorkaround() {

static bool NeedsNoRandomizeWorkaround() {