diff --git a/src/log.h b/src/log.h
index 3edc36d..e1d181c 100644
--- a/src/log.h
+++ b/src/log.h
@@ -46,13 +46,13 @@ inline void LogPrintf(
 
   snprintf(line_buffer, sizeof(line_buffer), "%d", line);
   // Start with "__FILENAME__:__LINE__ ".
-  strncat(buffer, file, strlen(file));
+  strncat(buffer, file, rest);
   rest -= strlen(file);
-  strncat(buffer, ":", 1);
+  strncat(buffer, ":", rest);
   rest -= 1;
-  strncat(buffer, line_buffer, strlen(line_buffer));
+  strncat(buffer, line_buffer, rest);
   rest -= strlen(line_buffer);
-  strncat(buffer, " ", 1);
+  strncat(buffer, " ", rest);
   rest -= 1;
 
   // Sanity check.
@@ -69,10 +69,10 @@ inline void LogPrintf(
     // For copying the suffix we need actual rest value again.
     strncpy(rest_start + (rest - strlen(truncate_suffix)),
             truncate_suffix,
-            strlen(truncate_suffix));
+            rest);
   }
 
-  strncat(buffer, "\n", 1);
+  strncat(buffer, "\n", rest);
 
   // Sanity check.
   if (buffer[kLogLen-1] != 0) {