update_engine: Use FileStream in FilesystemVerifierAction.

Instead of dealing manually with the read from the partition while
verifying the filesystem, this patch uses chromeos::FileStream to do
that.

The base::MessageLoopForIO can't wait on regular files because libevent
will fail when trying to watch for such file descriptor. While
chromeos::Stream will still attempt to wait on the file descriptor in
such situation, that will be fixed in chromeos::Streams in a different
CL.

BUG=chromium:499886
TEST=Unittests still pass.

Change-Id: Icd6a031ac1137b1b5746a5c3413506ece79223cc
Reviewed-on: https://chromium-review.googlesource.com/290542
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
Trybot-Ready: Alex Deymo <deymo@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>

1 files changed, 13 insertions, 12 deletions

diff --git a/filesystem_verifier_action_unittest.cc b/filesystem_verifier_action_unittest.cc
index da0fd955..66f8571a 100644
--- a/filesystem_verifier_action_unittest.cc
+++ b/filesystem_verifier_action_unittest.cc
@@ -352,6 +352,8 @@ TEST_F(FilesystemVerifierActionTest, RunAsRootVerifyHashFailTest) {
 TEST_F(FilesystemVerifierActionTest, RunAsRootTerminateEarlyTest) {
   ASSERT_EQ(0, getuid());
   EXPECT_TRUE(DoTest(true, false, PartitionType::kKernel));
+  // TerminateEarlyTest may leak some null callbacks from the Stream class.
+  while (loop_.RunOnce(false)) {}
 }
 
 TEST_F(FilesystemVerifierActionTest, RunAsRootDetermineFilesystemSizeTest) {
@@ -362,19 +364,18 @@ TEST_F(FilesystemVerifierActionTest, RunAsRootDetermineFilesystemSizeTest) {
   // Extend the "partition" holding the file system from 10MiB to 20MiB.
   EXPECT_EQ(0, truncate(img.c_str(), 20 * 1024 * 1024));
 
-  for (int i = 0; i < 2; ++i) {
-    PartitionType fs_type =
-        i ? PartitionType::kSourceKernel : PartitionType::kSourceRootfs;
-    FilesystemVerifierAction action(&fake_system_state_, fs_type);
+  {
+    FilesystemVerifierAction action(&fake_system_state_,
+                                    PartitionType::kSourceKernel);
     EXPECT_EQ(kint64max, action.remaining_size_);
-    {
-      int fd = HANDLE_EINTR(open(img.c_str(), O_RDONLY));
-      EXPECT_GT(fd, 0);
-      ScopedFdCloser fd_closer(&fd);
-      action.DetermineFilesystemSize(fd);
-    }
-    EXPECT_EQ(i ? kint64max : 10 * 1024 * 1024,
-              action.remaining_size_);
+    action.DetermineFilesystemSize(img);
+    EXPECT_EQ(kint64max, action.remaining_size_);
+  }
+  {
+    FilesystemVerifierAction action(&fake_system_state_,
+                                    PartitionType::kSourceRootfs);
+    action.DetermineFilesystemSize(img);
+    EXPECT_EQ(10 * 1024 * 1024, action.remaining_size_);
   }
 }