diff --git a/aos/util/file.cc b/aos/util/file.cc
index f952955..9c81b3e 100644
--- a/aos/util/file.cc
+++ b/aos/util/file.cc
@@ -3,20 +3,26 @@
 #include <fcntl.h>
 #include <unistd.h>
 
+#include "absl/strings/string_view.h"
 #include "aos/logging/logging.h"
 #include "aos/scoped/scoped_fd.h"
 
 namespace aos {
 namespace util {
 
-::std::string ReadFileToStringOrDie(const ::std::string &filename) {
+::std::string ReadFileToStringOrDie(const absl::string_view filename) {
   ::std::string r;
-  ScopedFD fd(PCHECK(open(filename.c_str(), O_RDONLY)));
+  ScopedFD fd(open(::std::string(filename).c_str(), O_RDONLY));
+  if (fd.get() == -1) {
+    PLOG(FATAL, "opening %*s", static_cast<int>(filename.size()),
+         filename.data());
+  }
   while (true) {
     char buffer[1024];
     const ssize_t result = read(fd.get(), buffer, sizeof(buffer));
     if (result < 0) {
-      PLOG(FATAL, "reading from %s", filename.c_str());
+      PLOG(FATAL, "reading from %*s", static_cast<int>(filename.size()),
+           filename.data());
     } else if (result == 0) {
       break;
     }