iPhone哪些案例无法获得mac地址成功？

Question

使用以下方法适用于99.5%的情况,但AppStore中的用户很少报告他们无法获取mac地址(我们使用标识符来验证每个服务器调用).

失败的案例基于iPhone 4S和IOS版本5.0.1.

大家好,

你知道哪种情况(除了低内存)它会失败吗？任何想法或讨论将不胜感激.谢谢.

/* Original source code courtesy John from iOSDeveloperTips.com */

#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>

- (NSString *)getMacAddress
{
    int                 mgmtInfoBase[6];
    char                *msgBuffer = NULL;
    NSString            *errorFlag = NULL;
    size_t              length;

    // Setup the management Information Base (mib)
    mgmtInfoBase[0] = CTL_NET;        // Request network subsystem
    mgmtInfoBase[1] = AF_ROUTE;       // Routing table info
    mgmtInfoBase[2] = 0;              
    mgmtInfoBase[3] = AF_LINK;        // Request link layer information
    mgmtInfoBase[4] = NET_RT_IFLIST;  // Request all configured interfaces

    // With all configured interfaces requested, get handle index
    if ((mgmtInfoBase[5] = if_nametoindex("en0")) == 0) 
        errorFlag = @"if_nametoindex failure";
    // Get the size of the data available (store in len)
    else if (sysctl(mgmtInfoBase, 6, NULL, &length, NULL, 0) < 0) 
        errorFlag = @"sysctl mgmtInfoBase failure";
    // Alloc memory based on above call
    else if ((msgBuffer = malloc(length)) == NULL)
        errorFlag = @"buffer allocation failure";
    // Get system information, store in buffer
    else if (sysctl(mgmtInfoBase, 6, msgBuffer, &length, NULL, 0) < 0)
    {
        free(msgBuffer);
        errorFlag = @"sysctl msgBuffer failure";
    }
    else
    {
        // Map msgbuffer to interface message structure
        struct if_msghdr *interfaceMsgStruct = (struct if_msghdr *) msgBuffer;

        // Map to link-level socket structure
        struct sockaddr_dl *socketStruct = (struct sockaddr_dl *) (interfaceMsgStruct + 1);

        // Copy link layer address data in socket structure to an array
        unsigned char macAddress[6];
        memcpy(&macAddress, socketStruct->sdl_data + socketStruct->sdl_nlen, 6);

        // Read from char array into a string object, into traditional Mac address format
        NSString *macAddressString = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X",
                                      macAddress[0], macAddress[1], macAddress[2], macAddress[3], macAddress[4], macAddress[5]];
        NSLog(@"Mac Address: %@", macAddressString);

        // Release the buffer memory
        free(msgBuffer);

        return macAddressString;
    }

    // Error...
    NSLog(@"Error: %@", errorFlag);

    return errorFlag;
}

任何帮助是极大的赞赏.

Answer 1

在将 iPhone 升级到 iOS 5 后，我遇到了这样的情况，问题是臭名昭著的 wifi 错误。你不会喜欢这个答案，但唯一的解决方案是将设备带回苹果并购买一台可以正常工作的新设备。可以将代码更改为在 mac 地址查找失败时不会崩溃，但是当 REST 调用需要唯一标识符时，这没有帮助。作为一名开发人员，您进退两难。