The USB device is mounted multiple times.

After the system is started, it is found that the same USB device has been attached multiple times, causing problems in the File Manager applications. The process of attaching a USB device is in Android/system/vold/volume. cpp and is handled by the volume: mountudiskvol function. You can solve this problem by checking whether the device has been mounted before mounting:

 
Bool isusbdevicemounted (const char * path) {char device [256]; char mount_path [256]; char rest [256]; file * FP; char line [1024]; If (! (FP = fopen ("/proc/mounts", "R") {sloge ("error opening/proc/mounts (% s)", strerror (errno )); return false;} while (fgets (line, sizeof (line), FP) {line [strlen (line)-1] = '\ 0'; sscanf (line, "% 255 S % 255 S % 255s \ n", device, mount_path, rest); If (! Strcmp (device, PATH) {fclose (FP); Return true ;}} fclose (FP); Return false ;}
 

Int volume: mountudiskvol () {... For (IT = mudiskpartition-> begin (); it! = Mudiskpartition-> end (); It ++) {imajor = (* It)-> imajor; iminor = (* It)-> iminor; sprintf (devicepath, "/dev/block/vold/% d: % d", imajor, iminor); If (isusbdevicemounted (devicepath) continue ;...}...}