Fix prevent issues

Fix prevent issues

This commit fixes following prevent CIDs:
 * 458876: Avoid copying string which cannot be null-terminated
 * 459717: NULL-check after memory allocation
 * 461686: NULL-check tainted scalar(string read by fgets())
 * 462630: NULL-check after memory allocation
 * 466499: NULL-check after memory allocation
 * 470326: NULL-check after memory allocation
 * 471806: NULL-check after memory allocation
 * 472387: NULL-check after memory allocation
 * 475993: NULL-check after memory allocation

Change-Id: Ie33494a2055528ae1c8b8ffb296a2111c3468e95