是否可以替换Mac登录屏幕? [英] Is it possible to replace the Mac login screen?

问题描述

是否可以用自定义登录窗口应用程序替换Mac OS X登录窗口/System/Library/CoreServices/loginwindow.app? (请参阅我这样做的理由.)

Is it possible to replace the Mac OS X login window, /System/Library/CoreServices/loginwindow.app, with a custom login window application? (See my rational for doing so.)

恐怕我的可可编程技能还很初级.我确实发现有趣的一点是，当我运行探针CGSession时(它是一个未记录的实用程序，它会执行快速切换用户)，通过执行操作查看

I'm afraid my Cocoa programming skills are rudimentary. I do find it interesting that, when I run probe CGSession (which is a undocumented utility that performs fast user switching) to see what functions it uses, by doing

nm -mg /System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession

链接功能之一是:

(undefined [lazy bound]) external _CGSCreateLoginSession (from ApplicationServices)

我还没有找到有关ApplicationServices框架的文档.我怀疑我正在深入研究服务提供商接口，而不是应用程序程序员接口.

I haven't found documentation on the ApplicationServices framework. I suspect I'm getting deep into Service Provider Interfaces instead of Application Programmer Interfaces.

我确实发现了这个非常有趣的代码段:(

I did find this really interesting snippet: (google cache) (direct link to down page; it appears the site is undergoing re-organization) from an application that claims to switch to the login window even if fast user switching is disabled.

#include "CGSInternal.h"

int main (int argc, const char * argv[]) {
    // switch to the login window
    CGSCreateLoginSession(NULL);

    return 0;
}

我以CG表示CoreGraphics，但不了解与登录有什么关系(除非可能在当前用户的工作上放置一个登录对话框).

I take CG to mean CoreGraphics, and don't understand what that has to do with logging in (except with perhaps putting a login dialog up over the current user's work).

即使无法替代登录窗口，我也想知道(不为Apple工作的人)可以采取哪些措施.

Even if it is not possible to achieve a replacement for the login window, I'd be interested to know what can be done along these lines (by people who don't work for Apple).

推荐答案

登录窗口应用程序被定义为/System/Library/LaunchDaemons/com.apple.loginwindow.plist .

The login window application is defined as part of the launchd configuration in /System/Library/LaunchDaemons/com.apple.loginwindow.plist.

理论上，您可以用自己的登录窗口替换，但是我不知道您在新应用程序中必须执行的操作-我认为登录窗口的功能比身份验证和设置用户会话还要多->其他情况，似乎是在做一些相关的琐事.

In theory you can replace the login window with your own but I don't know what you have to do in the new app - I think the login window does a bit more then authentication and setting up the user session -> amongst others, it looks like its doing some launchd related chores.

我已经编译了一个调用 CGSCreateLoginSession 的应用程序，一旦运行它，它就会通过旋转的多维数据集转换到登录窗口.我想这就是为什么它需要CoreGraphics的原因-它只是一个图形函数，最后需要注销.

I've compiled an application that calls CGSCreateLoginSession and once you run it it transitions to the login window via the rotating cube. I imagine this is why it requires CoreGraphics - it's just a graphics function that calls logout at the end.

您可以尝试使用InputManager并查看登录窗口是否加载了代码->如果这样做，则可以更改loginwindow NIB( LoginWindowUI.nib )并添加一些按钮以显示新的用户浏览器打开的窗口.学生选择了自己的照片后，您可以在登录窗口中自动填写用户名和密码字段.

You could try an InputManager and see it the login window loads the code -> if it does, you could then alter the loginwindow NIB (LoginWindowUI.nib) and add some buttons to display a new window with the user browser. Once the student chooses a picture of him/herself you could autofill the username and password fields in the loginwindow.

这完全是理论上的事，它看起来非常脆弱且不安全.

Node this is all theory, and it looks very fragile and unsafe.

祝你好运.

稍后编辑

请注意，这是非常不安全的，因此请谨慎使用-在尝试使用此工具时，我确实用了几次软管

这是一个概念验证的实现，可将代码注入到登录窗口中.

Here's a proof-of-concept implementation that injects code in the loginwindow.

#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <strings.h>
#include <syslog.h>

#import <Cocoa/Cocoa.h>

#include <execinfo.h>

@interface LLApp:NSApplication
@end
@implementation LLApp
- (void)run
{
    syslog(LOG_ERR, "LLApp being run");
    [super run];
}
@end

void my_openlog(const char *ident, int logopt, int facility);

typedef struct interpose_s 
{
        void * new_func;
        void * orig_func;
} interpose_t;

int MyNSApplicationMain(int argc,  const char ** argv);


static const interpose_t interposers[] __attribute__ ((section("__DATA, __interpose")))     = {
{ (void *) my_openlog, (void *) openlog },
};

void my_openlog(const char *ident, int logopt, int facility)
{
        openlog(ident, logopt, facility);

    if(!strcmp(ident, "/System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow"))
    {

        [LLApp poseAsClass:[NSApplication class]];
    }
    else
    {
        syslog(LOG_ERR, "Ignoring unknown indent: >%s<", ident);
    }
    return;
}

代码使用以下代码进行编译:

The code compiles with:

gcc -Wall -dynamiclib -undefined dynamic_lookup -o ~/Desktop/libinterposers.dylib testin.m -framework Cocoa

代码加载是基于插入的，因此loginwindow的启动定义必须包含一个附加条目(以允许在动态链接器中进行插入)，即:

Code loading is based on interposing so the launchd definition of loginwindow has to contain an additional entry (to enable interposing in the dynamic linker), i.e.:

<key>EnvironmentVariables</key>
<dict>    
    <key>DYLD_INSERT_LIBRARIES</key>
    <string>path_to/Desktop/libinterposers.dylib</string>
</dict>

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