diff --git a/tests/libs/Android.build.dlext_testzip.mk b/tests/libs/Android.build.dlext_testzip.mk
index c06f4a9..56be1e2 100644
--- a/tests/libs/Android.build.dlext_testzip.mk
+++ b/tests/libs/Android.build.dlext_testzip.mk
@@ -18,6 +18,8 @@
 # Library used by dlext tests - zipped and aligned
 # -----------------------------------------------------------------------------
 
+BIONIC_TESTS_ZIPALIGN := $(HOST_OUT_EXECUTABLES)/bionic_tests_zipalign
+
 include $(CLEAR_VARS)
 
 LOCAL_MODULE_CLASS := SHARED_LIBRARIES
@@ -33,12 +35,12 @@
   $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libdlext_test_zip.so \
   $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libatest_simple_zip.so
 
-$(LOCAL_BUILT_MODULE) : $(my_shared_libs) | $(ZIPALIGN)
-	@echo "Zipalign: $@"
+$(LOCAL_BUILT_MODULE) : $(my_shared_libs) | $(BIONIC_TESTS_ZIPALIGN)
+	@echo "Aligning zip: $@"
 	$(hide) rm -rf $(dir $@) && mkdir -p $(dir $@)/libdir
 	$(hide) cp $^ $(dir $@)/libdir
 	$(hide) (cd $(dir $@) && touch empty_file.txt && zip -qrD0 $(notdir $@).unaligned empty_file.txt libdir/*.so)
-	$(hide) $(ZIPALIGN) -p 4 $@.unaligned $@
+	$(hide) $(BIONIC_TESTS_ZIPALIGN) 4096 $@.unaligned $@
 
 include $(CLEAR_VARS)
 
@@ -68,8 +70,8 @@
   $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libtest_dt_runpath_c.so
 $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_X := \
   $($(bionic_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/libtest_dt_runpath_x.so
-$(LOCAL_BUILT_MODULE) : $(my_shared_libs) | $(ZIPALIGN)
-	@echo "Zipalign: $@"
+$(LOCAL_BUILT_MODULE) : $(my_shared_libs) | $(BIONIC_TESTS_ZIPALIGN)
+	@echo "Aligning zip: $@"
 	$(hide) rm -rf $(dir $@) && mkdir -p $(dir $@)/libdir && \
     mkdir -p $(dir $@)/libdir/dt_runpath_a && mkdir -p $(dir $@)/libdir/dt_runpath_b_c_x
 	$(hide) cp $(PRIVATE_LIB_D) $(dir $@)/libdir
@@ -78,5 +80,5 @@
 	$(hide) cp $(PRIVATE_LIB_C) $(dir $@)/libdir/dt_runpath_b_c_x
 	$(hide) cp $(PRIVATE_LIB_X) $(dir $@)/libdir/dt_runpath_b_c_x
 	$(hide) (cd $(dir $@) && touch empty_file.txt && zip -qrD0 $(notdir $@).unaligned empty_file.txt libdir)
-	$(hide) $(ZIPALIGN) -p 4 $@.unaligned $@
+	$(hide) $(BIONIC_TESTS_ZIPALIGN) 4096 $@.unaligned $@
 
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index 93d95ee..506d6f2 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -486,3 +486,18 @@
 
 module := libtest_dlopen_from_ctor_main
 include $(LOCAL_PATH)/Android.build.testlib.mk
+
+# -----------------------------------------------------------------------------
+# Tool to use to align the shared libraries in a zip file.
+# -----------------------------------------------------------------------------
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := bionic_tests_zipalign.cpp
+LOCAL_MODULE := bionic_tests_zipalign
+LOCAL_CFLAGS := -Wall -Werror
+
+LOCAL_STATIC_LIBRARIES := libziparchive-host liblog libbase libz libutils
+
+LOCAL_MODULE_HOST_OS := darwin linux windows
+
+include $(BUILD_HOST_EXECUTABLE)
diff --git a/tests/libs/bionic_tests_zipalign.cpp b/tests/libs/bionic_tests_zipalign.cpp
new file mode 100644
index 0000000..dbbfd7c
--- /dev/null
+++ b/tests/libs/bionic_tests_zipalign.cpp
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+#include <ziparchive/zip_archive.h>
+#include <ziparchive/zip_archive_stream_entry.h>
+#include <ziparchive/zip_writer.h>
+
+static void usage() {
+  fprintf(stderr, "usage: bionic_tests_zipalign ALIGNMENT INPUT_ZIP_FILE OUTPUT_ZIP_FILE\n");
+  fprintf(stderr, "  ALIGNMENT:\n");
+  fprintf(stderr, "    The new alignment of all entries in the new zip file.\n");
+  fprintf(stderr, "  INPUT_ZIP_FILE:\n");
+  fprintf(stderr, "    The input zip file that will be read but left unmodified.\n");
+  fprintf(stderr, "  OUTPUT_ZIP_FILE:\n");
+  fprintf(stderr, "    The output zip file that will be created from the input file.\n");
+}
+
+typedef std::pair<ZipEntry*, ZipString*> ZipData;
+
+static bool GetEntries(ZipArchiveHandle handle, std::vector<ZipData>* entries) {
+  void* cookie;
+  int32_t return_value = StartIteration(handle, &cookie, nullptr, nullptr);
+  if (return_value != 0) {
+    fprintf(stderr, "Unable to iterate over entries: %s\n", ErrorCodeString(return_value));
+    return false;
+  }
+
+  ZipEntry entry;
+  ZipString name;
+  while ((return_value = Next(cookie, &entry, &name)) == 0) {
+    entries->push_back(std::make_pair(new ZipEntry(entry), new ZipString(name)));
+  }
+  if (return_value != -1) {
+    fprintf(stderr, "Error while iterating over zip entries: %s\n", ErrorCodeString(return_value));
+  } else {
+    // Sort by offset.
+    std::sort(entries->begin(), entries->end(),
+              [](ZipData a, ZipData b) { return a.first->offset < b.first->offset; });
+  }
+
+  EndIteration(cookie);
+  return return_value == -1;
+}
+
+static bool CreateAlignedZip(ZipArchiveHandle& handle, FILE* zip_dst, uint32_t alignment) {
+  std::vector<ZipData> entries;
+  // We will not free the memory created in entries since the program
+  // terminates right after this function is called.
+  if (!GetEntries(handle, &entries)) {
+    return false;
+  }
+
+  ZipWriter writer(zip_dst);
+
+  int32_t error;
+  for (auto& entry : entries) {
+    ZipEntry* zip_entry = entry.first;
+    ZipString* zip_str = entry.second;
+
+    size_t flags = 0;
+    if ((zip_entry->method & kCompressDeflated) != 0) {
+      flags |= ZipWriter::kCompress;
+    }
+    std::string zip_name(reinterpret_cast<const char*>(zip_str->name), zip_str->name_length);
+    error = writer.StartAlignedEntry(zip_name.c_str(), flags, alignment);
+    if (error != 0) {
+      fprintf(stderr, "StartAlignedEntry failed: %s\n", ZipWriter::ErrorCodeString(error));
+      return false;
+    }
+    std::unique_ptr<ZipArchiveStreamEntry> stream(
+        ZipArchiveStreamEntry::Create(handle, *zip_entry));
+    const std::vector<uint8_t>* data;
+    while ((data = stream->Read()) != nullptr) {
+      error = writer.WriteBytes(data->data(), data->size());
+      if (error != 0) {
+        fprintf(stderr, "WriteBytes failed: %s\n", ZipWriter::ErrorCodeString(error));
+        return false;
+      }
+    }
+    if (!stream->Verify()) {
+      fprintf(stderr, "Failed to verify zip stream writer entry.\n");
+      return false;
+    }
+    error = writer.FinishEntry();
+    if (error != 0) {
+      fprintf(stderr, "FinishEntry failed: %s\n", ZipWriter::ErrorCodeString(error));
+    }
+  }
+
+  error = writer.Finish();
+  if (error != 0) {
+    fprintf(stderr, "Finish failed: %s\n", ZipWriter::ErrorCodeString(error));
+    return false;
+  }
+  return true;
+}
+
+int main(int argc, char* argv[]) {
+  if (argc != 4) {
+    usage();
+    return 1;
+  }
+
+  char* end;
+  unsigned long int alignment = strtoul(argv[1], &end, 10);
+  if ((alignment == ULONG_MAX && errno == ERANGE) || *end != '\0') {
+    fprintf(stderr, "ALIGNMENT value is not a valid number: %s\n", argv[1]);
+    usage();
+    return 1;
+  }
+  if (((alignment - 1) & alignment) != 0) {
+    fprintf(stderr, "ALIGNMENT value is not a power of 2: %s\n", argv[1]);
+    return 1;
+  }
+
+  ZipArchiveHandle handle;
+
+  int32_t return_value = OpenArchive(argv[2], &handle);
+  if (return_value != 0) {
+    fprintf(stderr, "Unable to open '%s': %s\n", argv[2], ErrorCodeString(return_value));
+    return false;
+  }
+
+  FILE* zip_dst = fopen(argv[3], "we");
+  if (zip_dst == nullptr) {
+    fprintf(stderr, "Unable to create '%s': %s\n", argv[3], strerror(errno));
+    return 1;
+  }
+
+  bool success = CreateAlignedZip(handle, zip_dst, static_cast<uint32_t>(alignment));
+
+  CloseArchive(handle);
+  fclose(zip_dst);
+
+  return success ? 0 : 1;
+}