Revert "Ensure dex file are extracted and verified at load time"

The art build bot fails for the oat location tests. I suspect that ScopedNonWritable is not working properly on the bot.

This reverts commit d2510c92e7c1f571ab012fcb82e77d7e1806ae3b.

Change-Id: Ica70862fd608ebdeb3c710f786ae21b99b69bc20
diff --git a/runtime/oat_file_assistant.cc b/runtime/oat_file_assistant.cc
index 603bbbf..eafa77f 100644
--- a/runtime/oat_file_assistant.cc
+++ b/runtime/oat_file_assistant.cc
@@ -68,34 +68,19 @@
 OatFileAssistant::OatFileAssistant(const char* dex_location,
                                    const InstructionSet isa,
                                    bool load_executable)
+    : OatFileAssistant(dex_location, nullptr, isa, load_executable)
+{ }
+
+OatFileAssistant::OatFileAssistant(const char* dex_location,
+                                   const char* oat_location,
+                                   const InstructionSet isa,
+                                   bool load_executable)
     : isa_(isa),
       load_executable_(load_executable),
       odex_(this, /*is_oat_location*/ false),
       oat_(this, /*is_oat_location*/ true) {
   CHECK(dex_location != nullptr) << "OatFileAssistant: null dex location";
-
-  // Try to get the realpath for the dex location.
-  //
-  // This is OK with respect to dalvik cache naming scheme because we never
-  // generate oat files starting from symlinks which go into dalvik cache.
-  // (recall that the oat files in dalvik cache are encoded by replacing '/'
-  // with '@' in the path).
-  // The boot image oat files (which are symlinked in dalvik-cache) are not
-  // loaded via the oat file assistant.
-  //
-  // The only case when the dex location may resolve to a different path
-  // is for secondary dex files (e.g. /data/user/0 symlinks to /data/data and
-  // the app is free to create its own internal layout). Related to this it is
-  // worthwhile to mention that installd resolves the secondary dex location
-  // before calling dex2oat.
-  UniqueCPtr<const char[]> dex_location_real(realpath(dex_location, nullptr));
-  if (dex_location_real != nullptr) {
-    dex_location_.assign(dex_location_real.get());
-  } else {
-    // If we can't get the realpath of the location there's not much point in trying to move on.
-    PLOG(ERROR) << "Could not get the realpath of dex_location " << dex_location;
-    return;
-  }
+  dex_location_.assign(dex_location);
 
   if (load_executable_ && isa != kRuntimeISA) {
     LOG(WARNING) << "OatFileAssistant: Load executable specified, "
@@ -113,27 +98,15 @@
   }
 
   // Get the oat filename.
-  std::string oat_file_name;
-  if (DexLocationToOatFilename(dex_location_, isa_, &oat_file_name, &error_msg)) {
-    oat_.Reset(oat_file_name);
+  if (oat_location != nullptr) {
+    oat_.Reset(oat_location);
   } else {
-    LOG(WARNING) << "Failed to determine oat file name for dex location "
-        << dex_location_ << ": " << error_msg;
-  }
-
-  // Check if the dex directory is writable.
-  // This will be needed in most uses of OatFileAssistant and so it's OK to
-  // compute it eagerly. (the only use which will not make use of it is
-  // OatFileAssistant::GetStatusDump())
-  size_t pos = dex_location_.rfind('/');
-  if (pos == std::string::npos) {
-    LOG(WARNING) << "Failed to determine dex file parent directory: " << dex_location_;
-  } else {
-    std::string parent = dex_location_.substr(0, pos);
-    if (access(parent.c_str(), W_OK) == 0) {
-      dex_parent_writable_ = true;
+    std::string oat_file_name;
+    if (DexLocationToOatFilename(dex_location_, isa_, &oat_file_name, &error_msg)) {
+      oat_.Reset(oat_file_name);
     } else {
-      VLOG(oat) << "Dex parent of " << dex_location_ << " is not writable: " << strerror(errno);
+      LOG(WARNING) << "Failed to determine oat file name for dex location "
+        << dex_location_ << ": " << error_msg;
     }
   }
 }
@@ -166,17 +139,12 @@
   CHECK(error_msg != nullptr);
   CHECK(!flock_.HasFile()) << "OatFileAssistant::Lock already acquired";
 
-  // Note the lock will only succeed for secondary dex files and in test
-  // environment.
-  //
-  // The lock *will fail* for all primary apks in a production environment.
-  // The app does not have permissions to create locks next to its dex location
-  // (be it system, data or vendor parition). We also cannot use the odex or
-  // oat location for the same reasoning.
-  //
-  // This is best effort and if it fails it's unlikely that we will be able
-  // to generate oat files anyway.
-  std::string lock_file_name = dex_location_ + "." + GetInstructionSetString(isa_) + ".flock";
+  const std::string* oat_file_name = oat_.Filename();
+  if (oat_file_name == nullptr) {
+    *error_msg = "Failed to determine lock file";
+    return false;
+  }
+  std::string lock_file_name = *oat_file_name + ".flock";
 
   if (!flock_.Init(lock_file_name.c_str(), error_msg)) {
     unlink(lock_file_name.c_str());
@@ -202,7 +170,7 @@
   CHECK(filter != nullptr);
   CHECK(error_msg != nullptr);
 
-  *filter = OatFileAssistant::kDefaultCompilerFilterForDexLoading;
+  *filter = CompilerFilter::kDefaultCompilerFilter;
   for (StringPiece option : Runtime::Current()->GetCompilerOptions()) {
     if (option.starts_with("--compiler-filter=")) {
       const char* compiler_filter_string = option.substr(strlen("--compiler-filter=")).data();
@@ -239,7 +207,7 @@
     case kDex2OatForBootImage:
     case kDex2OatForRelocation:
     case kDex2OatForFilter:
-      return GenerateOatFileNoChecks(info, error_msg);
+      return GenerateOatFile(error_msg);
   }
   UNREACHABLE();
 }
@@ -511,110 +479,8 @@
   return kOatUpToDate;
 }
 
-static bool DexLocationToOdexNames(const std::string& location,
-                                   InstructionSet isa,
-                                   std::string* odex_filename,
-                                   std::string* oat_dir,
-                                   std::string* isa_dir,
-                                   std::string* error_msg) {
-  CHECK(odex_filename != nullptr);
-  CHECK(error_msg != nullptr);
-
-  // The odex file name is formed by replacing the dex_location extension with
-  // .odex and inserting an oat/<isa> directory. For example:
-  //   location = /foo/bar/baz.jar
-  //   odex_location = /foo/bar/oat/<isa>/baz.odex
-
-  // Find the directory portion of the dex location and add the oat/<isa>
-  // directory.
-  size_t pos = location.rfind('/');
-  if (pos == std::string::npos) {
-    *error_msg = "Dex location " + location + " has no directory.";
-    return false;
-  }
-  std::string dir = location.substr(0, pos+1);
-  // Add the oat directory.
-  dir += "oat";
-  if (oat_dir != nullptr) {
-    *oat_dir = dir;
-  }
-  // Add the isa directory
-  dir += "/" + std::string(GetInstructionSetString(isa));
-  if (isa_dir != nullptr) {
-    *isa_dir = dir;
-  }
-
-  // Get the base part of the file without the extension.
-  std::string file = location.substr(pos+1);
-  pos = file.rfind('.');
-  if (pos == std::string::npos) {
-    *error_msg = "Dex location " + location + " has no extension.";
-    return false;
-  }
-  std::string base = file.substr(0, pos);
-
-  *odex_filename = dir + "/" + base + ".odex";
-  return true;
-}
-
-// Prepare a subcomponent of the odex directory.
-// (i.e. create and set the expected permissions on the path `dir`).
-static bool PrepareDirectory(const std::string& dir, std::string* error_msg) {
-  struct stat dir_stat;
-  if (TEMP_FAILURE_RETRY(stat(dir.c_str(), &dir_stat)) == 0) {
-    // The directory exists. Check if it is indeed a directory.
-    if (!S_ISDIR(dir_stat.st_mode)) {
-      *error_msg = dir + " is not a dir";
-      return false;
-    } else {
-      // The dir is already on disk.
-      return true;
-    }
-  }
-
-  // Failed to stat. We need to create the directory.
-  if (errno != ENOENT) {
-    *error_msg = "Could not stat isa dir " + dir + ":" + strerror(errno);
-    return false;
-  }
-
-  mode_t mode = S_IRWXU | S_IXGRP | S_IXOTH;
-  if (mkdir(dir.c_str(), mode) != 0) {
-    *error_msg = "Could not create dir " + dir + ":" + strerror(errno);
-    return false;
-  }
-  if (chmod(dir.c_str(), mode) != 0) {
-    *error_msg = "Could not create the oat dir " + dir + ":" + strerror(errno);
-    return false;
-  }
-  return true;
-}
-
-// Prepares the odex directory for the given dex location.
-static bool PrepareOdexDirectories(const std::string& dex_location,
-                                   const std::string& expected_odex_location,
-                                   InstructionSet isa,
-                                   std::string* error_msg) {
-  std::string actual_odex_location;
-  std::string oat_dir;
-  std::string isa_dir;
-  if (!DexLocationToOdexNames(
-        dex_location, isa, &actual_odex_location, &oat_dir, &isa_dir, error_msg)) {
-    return false;
-  }
-  DCHECK_EQ(expected_odex_location, actual_odex_location);
-
-  if (!PrepareDirectory(oat_dir, error_msg)) {
-    return false;
-  }
-  if (!PrepareDirectory(isa_dir, error_msg)) {
-    return false;
-  }
-  return true;
-}
-
-OatFileAssistant::ResultOfAttemptToUpdate OatFileAssistant::GenerateOatFileNoChecks(
-      OatFileAssistant::OatFileInfo& info, std::string* error_msg) {
+OatFileAssistant::ResultOfAttemptToUpdate
+OatFileAssistant::GenerateOatFile(std::string* error_msg) {
   CHECK(error_msg != nullptr);
 
   Runtime* runtime = Runtime::Current();
@@ -624,37 +490,22 @@
     return kUpdateNotAttempted;
   }
 
-  if (info.Filename() == nullptr) {
+  if (oat_.Filename() == nullptr) {
     *error_msg = "Generation of oat file for dex location " + dex_location_
       + " not attempted because the oat file name could not be determined.";
     return kUpdateNotAttempted;
   }
-  const std::string& oat_file_name = *info.Filename();
+  const std::string& oat_file_name = *oat_.Filename();
   const std::string& vdex_file_name = ReplaceFileExtension(oat_file_name, "vdex");
 
   // dex2oat ignores missing dex files and doesn't report an error.
   // Check explicitly here so we can detect the error properly.
   // TODO: Why does dex2oat behave that way?
-  struct stat dex_path_stat;
-  if (TEMP_FAILURE_RETRY(stat(dex_location_.c_str(), &dex_path_stat)) != 0) {
-    *error_msg = "Could not access dex location " + dex_location_ + ":" + strerror(errno);
+  if (!OS::FileExists(dex_location_.c_str())) {
+    *error_msg = "Dex location " + dex_location_ + " does not exists.";
     return kUpdateNotAttempted;
   }
 
-  // If this is the odex location, we need to create the odex file layout (../oat/isa/..)
-  if (!info.IsOatLocation()) {
-    if (!PrepareOdexDirectories(dex_location_, oat_file_name, isa_, error_msg)) {
-      return kUpdateNotAttempted;
-    }
-  }
-
-  // Set the permissions for the oat and the vdex files.
-  // The user always gets read and write while the group and others propagate
-  // the reading access of the original dex file.
-  mode_t file_mode = S_IRUSR | S_IWUSR |
-      (dex_path_stat.st_mode & S_IRGRP) |
-      (dex_path_stat.st_mode & S_IROTH);
-
   std::unique_ptr<File> vdex_file(OS::CreateEmptyFile(vdex_file_name.c_str()));
   if (vdex_file.get() == nullptr) {
     *error_msg = "Generation of oat file " + oat_file_name
@@ -663,7 +514,7 @@
     return kUpdateNotAttempted;
   }
 
-  if (fchmod(vdex_file->Fd(), file_mode) != 0) {
+  if (fchmod(vdex_file->Fd(), 0644) != 0) {
     *error_msg = "Generation of oat file " + oat_file_name
       + " not attempted because the vdex file " + vdex_file_name
       + " could not be made world readable.";
@@ -677,7 +528,7 @@
     return kUpdateNotAttempted;
   }
 
-  if (fchmod(oat_file->Fd(), file_mode) != 0) {
+  if (fchmod(oat_file->Fd(), 0644) != 0) {
     *error_msg = "Generation of oat file " + oat_file_name
       + " not attempted because the oat file could not be made world readable.";
     oat_file->Erase();
@@ -712,8 +563,8 @@
     return kUpdateFailed;
   }
 
-  // Mark that the odex file has changed and we should try to reload.
-  info.Reset();
+  // Mark that the oat file has changed and we should try to reload.
+  oat_.Reset();
   return kUpdateSucceeded;
 }
 
@@ -772,7 +623,35 @@
                                                  InstructionSet isa,
                                                  std::string* odex_filename,
                                                  std::string* error_msg) {
-  return DexLocationToOdexNames(location, isa, odex_filename, nullptr, nullptr, error_msg);
+  CHECK(odex_filename != nullptr);
+  CHECK(error_msg != nullptr);
+
+  // The odex file name is formed by replacing the dex_location extension with
+  // .odex and inserting an oat/<isa> directory. For example:
+  //   location = /foo/bar/baz.jar
+  //   odex_location = /foo/bar/oat/<isa>/baz.odex
+
+  // Find the directory portion of the dex location and add the oat/<isa>
+  // directory.
+  size_t pos = location.rfind('/');
+  if (pos == std::string::npos) {
+    *error_msg = "Dex location " + location + " has no directory.";
+    return false;
+  }
+  std::string dir = location.substr(0, pos+1);
+  dir += "oat/" + std::string(GetInstructionSetString(isa));
+
+  // Get the base part of the file without the extension.
+  std::string file = location.substr(pos+1);
+  pos = file.rfind('.');
+  if (pos == std::string::npos) {
+    *error_msg = "Dex location " + location + " has no extension.";
+    return false;
+  }
+  std::string base = file.substr(0, pos);
+
+  *odex_filename = dir + "/" + base + ".odex";
+  return true;
 }
 
 bool OatFileAssistant::DexLocationToOatFilename(const std::string& location,
@@ -873,45 +752,8 @@
 }
 
 OatFileAssistant::OatFileInfo& OatFileAssistant::GetBestInfo() {
-  // TODO(calin): Document the side effects of class loading when
-  // running dalvikvm command line.
-  if (dex_parent_writable_) {
-    // If the parent of the dex file is writable it means that we can
-    // create the odex file. In this case we unconditionally pick the odex
-    // as the best oat file. This corresponds to the regular use case when
-    // apps gets installed or when they load private, secondary dex file.
-    // For apps on the system partition the odex location will not be
-    // writable and thus the oat location might be more up to date.
-    return odex_;
-  }
-
-  // We cannot write to the odex location. This must be a system app.
-
-  // If the oat location is usable take it.
-  if (oat_.IsUseable()) {
-    return oat_;
-  }
-
-  // The oat file is not usable but the odex file might be up to date.
-  // This is an indication that we are dealing with an up to date prebuilt
-  // (that doesn't need relocation).
-  if (odex_.Status() == kOatUpToDate) {
-    return odex_;
-  }
-
-  // The oat file is not usable and the odex file is not up to date.
-  // However we have access to the original dex file which means we can make
-  // the oat location up to date.
-  if (HasOriginalDexFiles()) {
-    return oat_;
-  }
-
-  // We got into the worst situation here:
-  // - the oat location is not usable
-  // - the prebuild odex location is not up to date
-  // - and we don't have the original dex file anymore (stripped).
-  // Pick the odex if it exists, or the oat if not.
-  return (odex_.Status() == kOatCannotOpen) ? oat_ : odex_;
+  bool use_oat = oat_.IsUseable() || odex_.Status() == kOatCannotOpen;
+  return use_oat ? oat_ : odex_;
 }
 
 std::unique_ptr<gc::space::ImageSpace> OatFileAssistant::OpenImageSpace(const OatFile* oat_file) {