Cocoa練習帳

アプリ内課金のレシートを自分で解析する方法を調べていたら、公式ドキュメントにIO Kitを使ったMACアドレスを取り出すコードが説明されていたので、面白いので、Swiftで実装したコマンドラインのプログラムとして動かしてみた。

import IOKit
import Foundation
 
// Returns an object with a +1 retain count; the caller needs to release.
func io_service(named name: String, wantBuiltIn: Bool) -> io_service_t? {
    let default_port = kIOMainPortDefault
    var iterator = io_iterator_t()
    defer {
        if iterator != IO_OBJECT_NULL {
            IOObjectRelease(iterator)
        }
    }
 
    // CFMutableDictionaryRef IOBSDNameMatching(mach_port_t mainPort, uint32_t options, const char *bsdName);
    guard let matchingDict = IOBSDNameMatching(default_port, 0, name),
        // kern_return_t IOServiceGetMatchingServices(mach_port_t mainPort, CFDictionaryRef matching, io_iterator_t *existing);
        IOServiceGetMatchingServices(default_port,
                                     matchingDict as CFDictionary,
                                     &iterator) == KERN_SUCCESS,
        iterator != IO_OBJECT_NULL
    else {
        return nil
    }
 
    // io_object_t IOIteratorNext(io_iterator_t iterator);
    var candidate = IOIteratorNext(iterator)
    while candidate != IO_OBJECT_NULL {
        // CFTypeRef IORegistryEntryCreateCFProperty(io_registry_entry_t entry, CFStringRef key, CFAllocatorRef allocator, IOOptionBits options);
        if let cftype = IORegistryEntryCreateCFProperty(candidate,
                                                        "IOBuiltin" as CFString,
                                                        kCFAllocatorDefault,
                                                        0) {
            let isBuiltIn = cftype.takeRetainedValue() as! CFBoolean
            if wantBuiltIn == CFBooleanGetValue(isBuiltIn) {
                return candidate
            }
        }
 
        IOObjectRelease(candidate)
        candidate = IOIteratorNext(iterator)
    }
 
    return nil
}
 
func copy_mac_address() -> CFData? {
    // Prefer built-in network interfaces.
    // For example, an external Ethernet adaptor can displace
    // the built-in Wi-Fi as en0.
    guard let service = io_service(named: "en0", wantBuiltIn: true)
            ?? io_service(named: "en1", wantBuiltIn: true)
            ?? io_service(named: "en0", wantBuiltIn: false)
        else { return nil }
    defer { IOObjectRelease(service) }
 
    // CFTypeRef IORegistryEntrySearchCFProperty(io_registry_entry_t entry, const io_name_t plane, CFStringRef key, CFAllocatorRef allocator, IOOptionBits options);
    if let cftype = IORegistryEntrySearchCFProperty(
        service,
        kIOServicePlane,
        "IOMACAddress" as CFString,
        kCFAllocatorDefault,
        IOOptionBits(kIORegistryIterateRecursively | kIORegistryIterateParents)) {
            return (cftype as! CFData)
    }
 
    return nil
}
 
func hexaDecimalString(_ cfData: CFData) -> String {
    let data: Data = cfData as Data;
    let value = data.map {
        String(format: "%.2hhx", $0)
    }
    .joined(separator: ":")
    return value
}
 
if let cfData = copy_mac_address() {
    print("\(cfData)")
    print("\(hexaDecimalString(cfData))")
}

_ 【関連情報】