我想将一些数据保存到文件中。
我将代码添加到SurfaceFlinger. 并更改uid为root。并添加sdcard_rw组。
但它不能工作。
这是我的代码：
ALOGI("open file before");
int fd = open("/mnt/sdcard/test.bmp", O_RDWR| O_CREAT, 600);
ALOGI("open file after %d %d", fd, errno);
运行结果：
10-03 12:48:07.883 666 666 I RenderEngine: open file before
10-03 12:48:07.883 666 666 I RenderEngine: open file after -1 13
surfaceflinger的状态：
Uid: 0 0 0 0
Gid: 1003 1003 1003 1003
Ngid: 0
FDSize: 128
Groups: 0 1015 1026 3009
surfaceflinger.rc:
service surfaceflinger /system/bin/surfaceflinger
class core animation
user root
group graphics drmrpc readproc root sdcard_rw
capabilities SYS_NICE
onrestart restart zygote
task_profiles HighPerformance
socket pdx/system/vr/display/client stream 0666 system graphics u:object_r:pdx_display_client_endpoint_socket:s0
socket pdx/system/vr/display/manager stream 0666 system graphics u:object_r:pdx_display_manager_endpoint_socket:s0
socket pdx/system/vr/display/vsync stream 0666 system graphics u:object_r:pdx_display_vsync_endpoint_socket:s0
那么如何写文件呢？