[impellerc] Set file access mode of .iplr output to 0644 (#35186)

impeller/compiler/impellerc_main.cc

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include <filesystem>
+#include <system_error>
 
 #include "flutter/fml/backtrace.h"
 #include "flutter/fml/command_line.h"
@@ -20,6 +21,21 @@
 namespace impeller {
 namespace compiler {
 
+// Sets the file access mode of the file at path 'p' to 0644.
+static bool SetPermissiveAccess(const std::filesystem::path& p) {
+  auto permissions =
+      std::filesystem::perms::owner_read | std::filesystem::perms::owner_write |
+      std::filesystem::perms::group_read | std::filesystem::perms::others_read;
+  std::error_code error;
+  std::filesystem::permissions(p, permissions, error);
+  if (error) {
+    std::cerr << "Failed to set access on file '" << p
+              << "': " << error.message() << std::endl;
+    return false;
+  }
+  return true;
+}
+
 bool Main(const fml::CommandLine& command_line) {
   fml::InstallCrashHandler();
   if (command_line.HasOption("help")) {
@@ -110,6 +126,11 @@ bool Main(const fml::CommandLine& command_line) {
                   << std::endl;
         return false;
       }
+      // Tools that consume the runtime stage data expect the access mode to
+      // be 0644.
+      if (!SetPermissiveAccess(sl_file_name)) {
+        return false;
+      }
     } else {
       if (!fml::WriteAtomically(*switches.working_directory,
                                 sl_file_name.string().c_str(),