Simulator: add the argument to keep the updated images

Add the command line option to select the work directory and save the
updated image files. Because some people might have interested in
getting updated images from an ota file.

Also, fix a minor issue that the destination of package_extract_file
needs to be updated if it's a block device. Otherwise, an unintended
file may be extracted in the callers' directory.

Test: run simulation, run unit tests

Change-Id: Ic6a7db0580bc1748d6e080102e4654da4e41fd8c

updater/update_simulator_main.cpp

@@ -58,12 +58,16 @@ int main(int argc, char** argv) {
   std::string skip_function_file;
   std::string source_target_file;
   std::string package_name;
+  std::string work_dir;
+  bool keep_images = false;
 
   constexpr struct option OPTIONS[] = {
+    { "keep_images", no_argument, nullptr, 0 },
     { "oem_settings", required_argument, nullptr, 0 },
     { "ota_package", required_argument, nullptr, 0 },
     { "skip_functions", required_argument, nullptr, 0 },
     { "source", required_argument, nullptr, 0 },
+    { "work_dir", required_argument, nullptr, 0 },
     { nullptr, 0, nullptr, 0 },
   };
 
@@ -86,6 +90,10 @@ int main(int argc, char** argv) {
       source_target_file = optarg;
     } else if (option_name == "ota_package"s) {
       package_name = optarg;
+    } else if (option_name == "keep_images"s) {
+      keep_images = true;
+    } else if (option_name == "work_dir"s) {
+      work_dir = optarg;
     } else {
       Usage(argv[0]);
       return EXIT_FAILURE;
@@ -129,8 +137,11 @@ int main(int argc, char** argv) {
 
   TemporaryFile cmd_pipe;
   TemporaryDir source_temp_dir;
+  if (work_dir.empty()) {
+    work_dir = source_temp_dir.path;
+  }
 
-  BuildInfo source_build_info(source_temp_dir.path);
+  BuildInfo source_build_info(work_dir, keep_images);
   if (!source_build_info.ParseTargetFile(source_target_file, false)) {
     LOG(ERROR) << "Failed to parse the target file " << source_target_file;
     return EXIT_FAILURE;