chunk: Add helper function to create a chunk from data read from a file descriptor

src/libstrongswan/utils/chunk.h

@@ -99,6 +99,14 @@ void chunk_split(chunk_t chunk, const char *mode, ...);
  */
 bool chunk_write(chunk_t chunk, char *path, char *label, mode_t mask, bool force);
 
+/**
+ * Store data read from FD into a chunk
+ *
+ * @param fd			file descriptor to read from
+ * @return				chunk or chunk_empty on failure
+ */
+chunk_t chunk_from_fd(int fd);
+
 /**
  * Convert a chunk of data to hex encoding.
  *