Get block device from NSURL

Question

The question says it all. How can I get the block device from an NSURL representing, for example, a removable media? What I would like to get from /Volumes/MyDevice is something like /dev/disk2. I wonder if that is possible without using the IOKit framework! Any help is appreciated.

Answer 1

DiskArbitration.framework will get you there:

NSURL *volumeURL = [NSURL fileURLWithPath:@"/Volumes/YourDisk"];

DASessionRef session = DASessionCreate(kCFAllocatorDefault);
DADiskRef disk = DADiskCreateFromVolumePath(kCFAllocatorDefault,
                                            session,
                                            (__bridge CFURLRef)volumeURL);

NSDictionary *desc = CFBridgingRelease(DADiskCopyDescription(disk));

/* See DADisk.h for a list of available keys */
NSLog(@"%@", desc[(NSString *)kDADiskDescriptionMediaBSDNameKey]);

CFRelease(disk);
CFRelease(session);

As will statfs(2):

struct statfs s;
statfs([[volumeURL path] fileSystemRepresentation], &s);
printf("%s\n", s.f_mntfromname);