/default.prop中的ro.secure

ro.secure=1后，su的行为改变
adb shell: uid=0 gid=0 context=u:r:shell:s0
su       : uid=0 gid=0 context=u:r:su:s0
ro.secure=0
adb shell: uid=2000(shell) gid=2000(shell) groups=1003(graphics),1004(input),1007(log),1009(mount),1011(adb),1015(sdcard_rw),1028(sdcard_r),3001(net_bt_admin),3002(net_bt),3003(inet),3006(net_bw_stats) context=u:r:shell:s0
su: uid=0 gid=0 context=u:r:init_shell:s0