Log an error when an app loads duplicate dex files

Creating a class loader with duplicate dex files in its classpath is most
likely an unintended bug. That leads to rejecting any compiled code and
hurts performance by extracting in memory.

Test: run-test gtest
Bug: 149410951

Change-Id: Ieebb69c6bd03acbe95dd8bedb6101d70390b92d8

1 files changed, 68 insertions, 31 deletions

diff --git a/runtime/class_loader_context.cc b/runtime/class_loader_context.cc
index 98db62ef38..d2119db3ee 100644
--- a/runtime/class_loader_context.cc
+++ b/runtime/class_loader_context.cc
@@ -1277,6 +1277,43 @@ static inline bool AbsolutePathHasRelativeSuffix(const std::string& path,
          (std::string_view(path).substr(/*pos*/ path.size() - suffix.size()) == suffix);
 }
 
+// Returns true if the given dex names are mathing, false otherwise.
+static bool AreDexNameMatching(const std::string& actual_dex_name,
+                               const std::string& expected_dex_name) {
+  // Compute the dex location that must be compared.
+  // We shouldn't do a naive comparison `actual_dex_name == expected_dex_name`
+  // because even if they refer to the same file, one could be encoded as a relative location
+  // and the other as an absolute one.
+  bool is_dex_name_absolute = IsAbsoluteLocation(actual_dex_name);
+  bool is_expected_dex_name_absolute = IsAbsoluteLocation(expected_dex_name);
+  bool dex_names_match = false;
+
+  if (is_dex_name_absolute == is_expected_dex_name_absolute) {
+    // If both locations are absolute or relative then compare them as they are.
+    // This is usually the case for: shared libraries and secondary dex files.
+    dex_names_match = (actual_dex_name == expected_dex_name);
+  } else if (is_dex_name_absolute) {
+    // The runtime name is absolute but the compiled name (the expected one) is relative.
+    // This is the case for split apks which depend on base or on other splits.
+    dex_names_match =
+        AbsolutePathHasRelativeSuffix(actual_dex_name, expected_dex_name);
+  } else if (is_expected_dex_name_absolute) {
+    // The runtime name is relative but the compiled name is absolute.
+    // There is no expected use case that would end up here as dex files are always loaded
+    // with their absolute location. However, be tolerant and do the best effort (in case
+    // there are unexpected new use case...).
+    dex_names_match =
+        AbsolutePathHasRelativeSuffix(expected_dex_name, actual_dex_name);
+  } else {
+    // Both locations are relative. In this case there's not much we can be sure about
+    // except that the names are the same. The checksum will ensure that the files are
+    // are same. This should not happen outside testing and manual invocations.
+    dex_names_match = (actual_dex_name == expected_dex_name);
+  }
+
+  return dex_names_match;
+}
+
 bool ClassLoaderContext::ClassLoaderInfoMatch(
     const ClassLoaderInfo& info,
     const ClassLoaderInfo& expected_info,
@@ -1305,37 +1342,7 @@ bool ClassLoaderContext::ClassLoaderInfoMatch(
 
   if (verify_names) {
     for (size_t k = 0; k < info.classpath.size(); k++) {
-      // Compute the dex location that must be compared.
-      // We shouldn't do a naive comparison `info.classpath[k] == expected_info.classpath[k]`
-      // because even if they refer to the same file, one could be encoded as a relative location
-      // and the other as an absolute one.
-      bool is_dex_name_absolute = IsAbsoluteLocation(info.classpath[k]);
-      bool is_expected_dex_name_absolute = IsAbsoluteLocation(expected_info.classpath[k]);
-      bool dex_names_match = false;
-
-
-      if (is_dex_name_absolute == is_expected_dex_name_absolute) {
-        // If both locations are absolute or relative then compare them as they are.
-        // This is usually the case for: shared libraries and secondary dex files.
-        dex_names_match = (info.classpath[k] == expected_info.classpath[k]);
-      } else if (is_dex_name_absolute) {
-        // The runtime name is absolute but the compiled name (the expected one) is relative.
-        // This is the case for split apks which depend on base or on other splits.
-        dex_names_match =
-            AbsolutePathHasRelativeSuffix(info.classpath[k], expected_info.classpath[k]);
-      } else if (is_expected_dex_name_absolute) {
-        // The runtime name is relative but the compiled name is absolute.
-        // There is no expected use case that would end up here as dex files are always loaded
-        // with their absolute location. However, be tolerant and do the best effort (in case
-        // there are unexpected new use case...).
-        dex_names_match =
-            AbsolutePathHasRelativeSuffix(expected_info.classpath[k], info.classpath[k]);
-      } else {
-        // Both locations are relative. In this case there's not much we can be sure about
-        // except that the names are the same. The checksum will ensure that the files are
-        // are same. This should not happen outside testing and manual invocations.
-        dex_names_match = (info.classpath[k] == expected_info.classpath[k]);
-      }
+      bool dex_names_match = AreDexNameMatching(info.classpath[k], expected_info.classpath[k]);
 
       // Compare the locations.
       if (!dex_names_match) {
@@ -1393,4 +1400,34 @@ bool ClassLoaderContext::ClassLoaderInfoMatch(
   }
 }
 
+std::vector<const DexFile*> ClassLoaderContext::CheckForDuplicateDexFiles(
+    const std::vector<const DexFile*>& dex_files_to_check) {
+  DCHECK(dex_files_open_attempted_);
+  DCHECK(dex_files_open_result_);
+
+  std::vector<const DexFile*> result;
+
+  if (special_shared_library_) {
+    return result;
+  }
+
+  std::vector<ClassLoaderInfo*> work_list;
+  work_list.push_back(class_loader_chain_.get());
+  while (!work_list.empty()) {
+    ClassLoaderInfo* info = work_list.back();
+    work_list.pop_back();
+    for (size_t k = 0; k < info->classpath.size(); k++) {
+      for (const DexFile* dex_file : dex_files_to_check) {
+        if (info->checksums[k] == dex_file->GetLocationChecksum()
+            && AreDexNameMatching(info->classpath[k], dex_file->GetLocation())) {
+          result.push_back(dex_file);
+        }
+      }
+    }
+    AddToWorkList(info, work_list);
+  }
+
+  return result;
+}
+
 }  // namespace art