Basic code to get the Hardware Model of an iOS device in Objective-C. https://en.wikipedia.org/wiki/List_of_iOS_devices

iOS_Hardware_Model.txt

    // #import "sys/utsname.h"
    struct utsname systemInfo;
    uname(&systemInfo);
    NSString *deviceString = [NSString stringWithCString:systemInfo.machine
                                                encoding:NSUTF8StringEncoding];
    
    //iPhone
    if ([deviceString isEqualToString:@"iPhone1,1"])    return @"iPhone 1G";
    if ([deviceString isEqualToString:@"iPhone1,2"])    return @"iPhone 3G";
    if ([deviceString isEqualToString:@"iPhone2,1"])    return @"iPhone 3GS";
    if ([deviceString isEqualToString:@"iPhone3,1"])    return @"iPhone 4";
    if ([deviceString isEqualToString:@"iPhone3,2"])    return @"Verizon iPhone 4";
    if ([deviceString isEqualToString:@"iPhone4,1"])    return @"iPhone 4S";
    if ([deviceString isEqualToString:@"iPhone5,1"])    return @"iPhone 5";
    if ([deviceString isEqualToString:@"iPhone5,2"])    return @"iPhone 5";
    if ([deviceString isEqualToString:@"iPhone5,3"])    return @"iPhone 5C";
    if ([deviceString isEqualToString:@"iPhone5,4"])    return @"iPhone 5C";
    if ([deviceString isEqualToString:@"iPhone6,1"])    return @"iPhone 5S";
    if ([deviceString isEqualToString:@"iPhone6,2"])    return @"iPhone 5S";
    if ([deviceString isEqualToString:@"iPhone7,1"])    return @"iPhone 6 Plus";
    if ([deviceString isEqualToString:@"iPhone7,2"])    return @"iPhone 6";
    if ([deviceString isEqualToString:@"iPhone8,1"])    return @"iPhone 6s";
    if ([deviceString isEqualToString:@"iPhone8,2"])    return @"iPhone 6s Plus";
    if ([deviceString isEqualToString:@"iPhone8,4"])    return @"iPhone SE";
    if ([deviceString isEqualToString:@"iPhone9,1"])    return @"iPhone 7";
    if ([deviceString isEqualToString:@"iPhone9,3"])    return @"iPhone 7";
    if ([deviceString isEqualToString:@"iPhone9,2"])    return @"iPhone 7 Plus";
    if ([deviceString isEqualToString:@"iPhone9,4"])    return @"iPhone 7 Plus";
    if ([deviceString isEqualToString:@"iPhone10,1"])    return @"iPhone 8";
    if ([deviceString isEqualToString:@"iPhone10,4"])    return @"iPhone 8";
    if ([deviceString isEqualToString:@"iPhone10,2"])    return @"iPhone 8 Plus";
    if ([deviceString isEqualToString:@"iPhone10,5"])    return @"iPhone 8 Plus";
    if ([deviceString isEqualToString:@"iPhone10,3"])    return @"iPhone X";
    if ([deviceString isEqualToString:@"iPhone10,6"])    return @"iPhone X";
    
    //iPod
    if ([deviceString isEqualToString:@"iPod1,1"])      return @"iPod Touch 1G";
    if ([deviceString isEqualToString:@"iPod2,1"])      return @"iPod Touch 2G";
    if ([deviceString isEqualToString:@"iPod3,1"])      return @"iPod Touch 3G";
    if ([deviceString isEqualToString:@"iPod4,1"])      return @"iPod Touch 4G";
    if ([deviceString isEqualToString:@"iPod5,1"])      return @"iPod Touch 5G";
    if ([deviceString isEqualToString:@"iPod7,1"])      return @"iPod Touch 6G";
    
    //iPad
    if ([deviceString isEqualToString:@"iPad1,1"])      return @"iPad";
    if ([deviceString isEqualToString:@"iPad2,1"])      return @"iPad 2 (WiFi)";
    if ([deviceString isEqualToString:@"iPad2,2"])      return @"iPad 2 (GSM)";
    if ([deviceString isEqualToString:@"iPad2,3"])      return @"iPad 2 (CDMA)";
    if ([deviceString isEqualToString:@"iPad2,4"])      return @"iPad 2 (32nm)";
    if ([deviceString isEqualToString:@"iPad2,5"])      return @"iPad mini (WiFi)";
    if ([deviceString isEqualToString:@"iPad2,6"])      return @"iPad mini (GSM)";
    if ([deviceString isEqualToString:@"iPad2,7"])      return @"iPad mini (CDMA)";
    if ([deviceString isEqualToString:@"iPad3,1"])      return @"iPad 3(WiFi)";
    if ([deviceString isEqualToString:@"iPad3,2"])      return @"iPad 3(CDMA)";
    if ([deviceString isEqualToString:@"iPad3,3"])      return @"iPad 3(4G)";
    if ([deviceString isEqualToString:@"iPad3,4"])      return @"iPad 4 (WiFi)";
    if ([deviceString isEqualToString:@"iPad3,5"])      return @"iPad 4 (4G)";
    if ([deviceString isEqualToString:@"iPad3,6"])      return @"iPad 4 (CDMA)";
    if ([deviceString isEqualToString:@"iPad4,1"])      return @"iPad Air";
    if ([deviceString isEqualToString:@"iPad4,2"])      return @"iPad Air";
    if ([deviceString isEqualToString:@"iPad4,3"])      return @"iPad Air";
    if ([deviceString isEqualToString:@"iPad4,4"] ||
        [deviceString isEqualToString:@"iPad4,5"] ||
        [deviceString isEqualToString:@"iPad4,6"]) {
        return @"iPad mini 2";
    }
    if ([deviceString isEqualToString:@"iPad4,7"] ||
        [deviceString isEqualToString:@"iPad4,8"] ||
        [deviceString isEqualToString:@"iPad4,9"]) {
        return @"iPad mini 3";
    }
    if ([deviceString isEqualToString:@"iPad5,1"])      return @"iPad mini 4";
    if ([deviceString isEqualToString:@"iPad5,2"])      return @"iPad mini 4";
    if ([deviceString isEqualToString:@"iPad5,3"])      return @"iPad Air 2";
    if ([deviceString isEqualToString:@"iPad5,4"])      return @"iPad Air 2";
    if ([deviceString isEqualToString:@"iPad6,3"])      return @"iPad Pro 9.7-inch";
    if ([deviceString isEqualToString:@"iPad6,4"])      return @"iPad Pro 9.7-inch";
    if ([deviceString isEqualToString:@"iPad6,7"])      return @"iPad Pro 1G";
    if ([deviceString isEqualToString:@"iPad6,8"])      return @"iPad Pro 1G";
    if ([deviceString isEqualToString:@"iPad6,11"])      return @"iPad (2017)";
    if ([deviceString isEqualToString:@"iPad6,12"])      return @"iPad (2017)";
    if ([deviceString isEqualToString:@"iPad7,1"])      return @"iPad Pro 2G";
    if ([deviceString isEqualToString:@"iPad7,2"])      return @"iPad Pro 2G";
    if ([deviceString isEqualToString:@"iPad7,3"])      return @"iPad Pro 10.5-inch";
    if ([deviceString isEqualToString:@"iPad7,4"])      return @"iPad Pro 10.5-inch";
    
    if ([deviceString isEqualToString:@"i386"])         return @"Simulator";
    if ([deviceString isEqualToString:@"x86_64"])       return @"Simulator";
    
    return deviceString;