Name : Ryou Sungmin Student ID : 2018147553 Description : Program has structures which are t_mac. t_mac has information about uid, gid, document file name, data, user name, FILE pointer of policy, document file, log, operation type, access_type. After initiating t_mac, get uid, gid and user name by using getuid, getgid, getpwuid. The program parse argument and get filenames. And program parse mac.policy to get access_type (security clearance level of user). After get access_type, program start to check authority of file and decide ACCESS or NOT. If ACCESS allowed, program read or write file. All read/write opration ends, program drop privilege to safe excution. After drop privilege, program open log file and append log file.