diff --git a/updater/install.cpp b/updater/install.cpp
index 0d473fc..86359d9 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -74,6 +74,7 @@
 #endif
 
 #include "otautil/DirUtil.h"
+#include "otautil/ZipUtil.h"
 #include "print_sha1.h"
 #include "tune2fs.h"
 #include "updater/updater.h"
@@ -423,6 +424,36 @@
   return StringValue(frac_str);
 }
 
+// package_extract_dir(package_dir, dest_dir)
+//   Extracts all files from the package underneath package_dir and writes them to the
+//   corresponding tree beneath dest_dir. Any existing files are overwritten.
+//   Example: package_extract_dir("system", "/system")
+//
+//   Note: package_dir needs to be a relative path; dest_dir needs to be an absolute path.
+Value* PackageExtractDirFn(const char* name, State* state,
+                           const std::vector<std::unique_ptr<Expr>>&argv) {
+  if (argv.size() != 2) {
+    return ErrorAbort(state, kArgsParsingFailure, "%s() expects 2 args, got %zu", name,
+                      argv.size());
+  }
+
+  std::vector<std::string> args;
+  if (!ReadArgs(state, argv, &args)) {
+    return ErrorAbort(state, kArgsParsingFailure, "%s() Failed to parse the argument(s)", name);
+  }
+  const std::string& zip_path = args[0];
+  const std::string& dest_path = args[1];
+
+  ZipArchiveHandle za = static_cast<UpdaterInfo*>(state->cookie)->package_zip;
+
+  // To create a consistent system image, never use the clock for timestamps.
+  constexpr struct utimbuf timestamp = { 1217592000, 1217592000 };  // 8/1/2008 default
+
+  bool success = ExtractPackageRecursive(za, zip_path, dest_path, &timestamp, sehandle);
+
+  return StringValue(success ? "t" : "");
+}
+
 // package_extract_file(package_file[, dest_file])
 //   Extracts a single package_file from the update package and writes it to dest_file,
 //   overwriting existing files if necessary. Without the dest_file argument, returns the
@@ -1045,6 +1076,7 @@
   RegisterFunction("format", FormatFn);
   RegisterFunction("show_progress", ShowProgressFn);
   RegisterFunction("set_progress", SetProgressFn);
+  RegisterFunction("package_extract_dir", PackageExtractDirFn);
   RegisterFunction("package_extract_file", PackageExtractFileFn);
 
   RegisterFunction("getprop", GetPropFn);