When building APK for direct loading, check for multiple libraries.

build/android/rezip/rezip.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // rezip is a tool which is used to modify zip files. It reads in a
 // zip file and outputs a new zip file after applying various
 // transforms. The tool is used in the Android Chromium build process
 // to modify an APK file (which are zip files). The main application
 // of this is to modify the APK so that the shared library is no
 // longer compressed. Ironically, this saves both transmission and
@@ skipping 244 matching lines @@
     return extra_size;
   }
 
   assert(extra_size < kMaxExtraFieldInZip - padding);
   memset(extra_buffer + extra_size, 0, padding);
   return extra_size + padding;
 }
 
 // As only the read side API provides offsets, we check that we added the
 // correct amount of padding by reading the zip file we just generated.
-static bool CheckPageAlign(const char* out_zip_filename) {
+// Also enforce that only one library is in the APK.
+static bool CheckPageAlignAndOnlyOneLibrary(const char* out_zip_filename) {
   ScopedUnzip scoped_unzip(out_zip_filename);
   unzFile in_file = scoped_unzip.OpenOrDie();
 
   int err = 0;
+  int count = 0;
   bool checked = false;
   while (true) {
     char in_filename[kMaxFilenameInZip + 1];
     // Get info and extra field for current file.
     unz_file_info in_info;
     err = unzGetCurrentFileInfo(in_file,
                                 &in_info,
                                 in_filename,
                                 sizeof(in_filename) - 1,
                                 NULL,
                                 0,
                                 NULL,
                                 0);
     if (err != UNZ_OK) {
       LOG(ERROR) << "failed to get filename" << out_zip_filename;
       return false;
     }
     assert(in_info.size_filename <= kMaxFilenameInZip);
     in_filename[in_info.size_filename] = '\0';
 
     if (IsCrazyLibraryFilename(in_filename)) {
+      count++;
+      if (count > 1) {
+        LOG(ERROR)
+            << "Found more than one library in " << out_zip_filename << "\n"
+            << "Multiple libraries are not supported for APKs that use "
+            << "'load_library_from_zip_file'.\n"
+            << "See crbug/388223.\n"
+            << "Note, check that your build is clean.\n"
+            << "An unclean build can incorrectly incorporate old "
+            << "libraries in the APK.";
+        return false;
+      }
       err = unzOpenCurrentFile(in_file);
       if (err != UNZ_OK) {
         LOG(ERROR) << "failed to open subfile" << out_zip_filename << " "
                    << in_filename;
         return false;
       }
 
       const ZPOS64_T pos = unzGetCurrentFileZStreamPos64(in_file);
       const int alignment = pos % kPageSizeOnDevice;
       checked = (alignment == 0);
@@ skipping 205 matching lines @@
     exit(1);
   }
 
   if (!Rezip(in_zip_filename,
              out_zip_filename,
              align_fun,
              rename_fun,
              inflate_predicate_fun)) {
     exit(1);
   }
-  if (check_page_align && !CheckPageAlign(out_zip_filename)) {
+  if (check_page_align && !CheckPageAlignAndOnlyOneLibrary(out_zip_filename)) {
     exit(1);
   }
   return 0;
 }