diff --git a/common/utils.cc b/common/utils.cc
index e7b6975..fc89040 100644
--- a/common/utils.cc
+++ b/common/utils.cc
@@ -30,6 +30,7 @@
 #include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <time.h>
 #include <unistd.h>
 
 #include <algorithm>
@@ -1074,6 +1075,14 @@
   return file_name.value();
 }
 
+string GetTimeAsString(time_t utime) {
+  struct tm tm;
+  CHECK_EQ(localtime_r(&utime, &tm), &tm);
+  char str[16];
+  CHECK_EQ(strftime(str, sizeof(str), "%Y%m%d-%H%M%S", &tm), 15u);
+  return str;
+}
+
 }  // namespace utils
 
 }  // namespace chromeos_update_engine
diff --git a/common/utils.h b/common/utils.h
index 9dca9e8..c6c34f4 100644
--- a/common/utils.h
+++ b/common/utils.h
@@ -18,6 +18,7 @@
 #define UPDATE_ENGINE_COMMON_UTILS_H_
 
 #include <errno.h>
+#include <time.h>
 #include <unistd.h>
 
 #include <algorithm>
@@ -329,6 +330,9 @@
                              uint16_t* high_version,
                              uint16_t* low_version);
 
+// Return a string representation of |utime| for log file names.
+std::string GetTimeAsString(time_t utime);
+
 }  // namespace utils
 
 // Utility class to close a file descriptor