ART: Track Flush & Close in FdFile

Implement a check that aborts when a file hasn't been explicitly
flushed and closed when it is destructed.

Add WARN_UNUSED to FdFile methods.

Update dex2oat, patchoat, scoped_flock and some gtests to pass with
this.

(cherry picked from commit 9433ec60b325b708b9fa87e699ab4a6565741494)

Change-Id: I9ab03b1653e69f44cc98946dc89d764c3e045dd4
diff --git a/runtime/base/unix_file/fd_file.cc b/runtime/base/unix_file/fd_file.cc
index f29a7ec..6e5e7a1 100644
--- a/runtime/base/unix_file/fd_file.cc
+++ b/runtime/base/unix_file/fd_file.cc
@@ -14,28 +14,68 @@
  * limitations under the License.
  */
 
-#include "base/logging.h"
 #include "base/unix_file/fd_file.h"
+
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
+#include "base/logging.h"
+
 namespace unix_file {
 
-FdFile::FdFile() : fd_(-1), auto_close_(true) {
+FdFile::FdFile() : guard_state_(GuardState::kClosed), fd_(-1), auto_close_(true) {
 }
 
-FdFile::FdFile(int fd) : fd_(fd), auto_close_(true) {
+FdFile::FdFile(int fd, bool check_usage)
+    : guard_state_(check_usage ? GuardState::kBase : GuardState::kNoCheck),
+      fd_(fd), auto_close_(true) {
 }
 
-FdFile::FdFile(int fd, const std::string& path) : fd_(fd), file_path_(path), auto_close_(true) {
+FdFile::FdFile(int fd, const std::string& path, bool check_usage)
+    : guard_state_(check_usage ? GuardState::kBase : GuardState::kNoCheck),
+      fd_(fd), file_path_(path), auto_close_(true) {
   CHECK_NE(0U, path.size());
 }
 
 FdFile::~FdFile() {
+  if (kCheckSafeUsage && (guard_state_ < GuardState::kNoCheck)) {
+    if (guard_state_ < GuardState::kFlushed) {
+      LOG(::art::ERROR) << "File " << file_path_ << " wasn't explicitly flushed before destruction.";
+    }
+    if (guard_state_ < GuardState::kClosed) {
+      LOG(::art::ERROR) << "File " << file_path_ << " wasn't explicitly closed before destruction.";
+    }
+    CHECK_GE(guard_state_, GuardState::kClosed);
+  }
   if (auto_close_ && fd_ != -1) {
-    Close();
+    if (Close() != 0) {
+      PLOG(::art::WARNING) << "Failed to close file " << file_path_;
+    }
+  }
+}
+
+void FdFile::moveTo(GuardState target, GuardState warn_threshold, const char* warning) {
+  if (kCheckSafeUsage) {
+    if (guard_state_ < GuardState::kNoCheck) {
+      if (warn_threshold < GuardState::kNoCheck && guard_state_ >= warn_threshold) {
+        LOG(::art::ERROR) << warning;
+      }
+      guard_state_ = target;
+    }
+  }
+}
+
+void FdFile::moveUp(GuardState target, const char* warning) {
+  if (kCheckSafeUsage) {
+    if (guard_state_ < GuardState::kNoCheck) {
+      if (guard_state_ < target) {
+        guard_state_ = target;
+      } else if (target < guard_state_) {
+        LOG(::art::ERROR) << warning;
+      }
+    }
   }
 }
 
@@ -54,11 +94,28 @@
     return false;
   }
   file_path_ = path;
+  static_assert(O_RDONLY == 0, "Readonly flag has unexpected value.");
+  if (kCheckSafeUsage && (flags & (O_RDWR | O_CREAT | O_WRONLY)) != 0) {
+    // Start in the base state (not flushed, not closed).
+    guard_state_ = GuardState::kBase;
+  } else {
+    // We are not concerned with read-only files. In that case, proper flushing and closing is
+    // not important.
+    guard_state_ = GuardState::kNoCheck;
+  }
   return true;
 }
 
 int FdFile::Close() {
   int result = TEMP_FAILURE_RETRY(close(fd_));
+
+  // Test here, so the file is closed and not leaked.
+  if (kCheckSafeUsage) {
+    CHECK_GE(guard_state_, GuardState::kFlushed) << "File " << file_path_
+        << " has not been flushed before closing.";
+    moveUp(GuardState::kClosed, nullptr);
+  }
+
   if (result == -1) {
     return -errno;
   } else {
@@ -74,6 +131,7 @@
 #else
   int rc = TEMP_FAILURE_RETRY(fsync(fd_));
 #endif
+  moveUp(GuardState::kFlushed, "Flushing closed file.");
   return (rc == -1) ? -errno : rc;
 }
 
@@ -92,6 +150,7 @@
 #else
   int rc = TEMP_FAILURE_RETRY(ftruncate(fd_, new_length));
 #endif
+  moveTo(GuardState::kBase, GuardState::kClosed, "Truncating closed file.");
   return (rc == -1) ? -errno : rc;
 }
 
@@ -107,6 +166,7 @@
 #else
   int rc = TEMP_FAILURE_RETRY(pwrite(fd_, buf, byte_count, offset));
 #endif
+  moveTo(GuardState::kBase, GuardState::kClosed, "Writing into closed file.");
   return (rc == -1) ? -errno : rc;
 }
 
@@ -135,6 +195,7 @@
 
 bool FdFile::WriteFully(const void* buffer, size_t byte_count) {
   const char* ptr = static_cast<const char*>(buffer);
+  moveTo(GuardState::kBase, GuardState::kClosed, "Writing into closed file.");
   while (byte_count > 0) {
     ssize_t bytes_written = TEMP_FAILURE_RETRY(write(fd_, ptr, byte_count));
     if (bytes_written == -1) {
@@ -146,4 +207,38 @@
   return true;
 }
 
+void FdFile::Erase() {
+  TEMP_FAILURE_RETRY(SetLength(0));
+  TEMP_FAILURE_RETRY(Flush());
+  TEMP_FAILURE_RETRY(Close());
+}
+
+int FdFile::FlushCloseOrErase() {
+  int flush_result = TEMP_FAILURE_RETRY(Flush());
+  if (flush_result != 0) {
+    LOG(::art::ERROR) << "CloseOrErase failed while flushing a file.";
+    Erase();
+    return flush_result;
+  }
+  int close_result = TEMP_FAILURE_RETRY(Close());
+  if (close_result != 0) {
+    LOG(::art::ERROR) << "CloseOrErase failed while closing a file.";
+    Erase();
+    return close_result;
+  }
+  return 0;
+}
+
+int FdFile::FlushClose() {
+  int flush_result = TEMP_FAILURE_RETRY(Flush());
+  if (flush_result != 0) {
+    LOG(::art::ERROR) << "FlushClose failed while flushing a file.";
+  }
+  int close_result = TEMP_FAILURE_RETRY(Close());
+  if (close_result != 0) {
+    LOG(::art::ERROR) << "FlushClose failed while closing a file.";
+  }
+  return (flush_result != 0) ? flush_result : close_result;
+}
+
 }  // namespace unix_file