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我有通用内核扩展，它在 C++ 示例中实现，用于开始和结束例程，而所有其他逻辑都存储在一个专用类中，继承自OSObject.

它在模块启动例程时创建类，并在停止例程时释放它，如下面的代码所示：

class com_my_driver : public OSObject { ... };

...
..
.

com_my_driver *gDriver = NULL;

extern "C" kern_return_t my_driver_start(kmod_info_t * ki, void *d)
{
    gDriver = new com_my_driver;
    gDriver->init();
    return KERN_SUCCESS;
}

extern "C" kern_return_t my_driver_stop(kmod_info_t *ki, void *d)
{
    gDriver->release();
    gDriver = nullptr;
    return KERN_SUCCESS;
}

但是，当尝试卸载服务时，它无法到达停止例程，因为该类仍在被引用（我假设它到达了我释放此类的停止例程）。这是确切的日志消息：

(kernel) Can't unload kext com.my.driver; classes have instances:
(kernel)     Kext com.my.driver class com_my_driver has 1 instance.
Failed to unload com.my.driver - (libkern/kext) kext is in use or retained (cannot unload).

在参考检查之前我可以在停止例行程序之前释放我的课程吗？

谢谢

4

1 回答 1

0

我最近遇到了同样的问题，然后我放弃了（在 kext stop 函数中释放我的课程）。
我认为 OSObject 及其派生类不适用于这种用例。

创建和删除（释放）必须在另一个地方完成，例如：

// do new in connect(), release in disconnect().
#include <sys/kern_control.h>
...
static kern_ctl_ref g_ctl_ref;
static kern_ctl_reg g_ctl;

...
static errno_t setup() {
    g_ctl.ctl_id = 0;
    g_ctl.ctl_flags = CTL_FLAG_REG_ID_UNIT /*| CTL_FLAG_REG_SOCK_STREAM */;
    g_ctl.ctl_connect = connect_handler;
    g_ctl.ctl_send = send_handler;
    g_ctl.ctl_disconnect = disconnect_handler;
    g_ctl.ctl_getopt = getopt_handler;
    g_ctl.ctl_setopt = setopt_handler;

    strcpy(g_ctl.ctl_name, "kext_control_name");
    g_ctl.ctl_unit = 0;

    return ctl_register(&g_ctl, &g_ctl_ref);
}

static errno_t connect_handler(kern_ctl_ref ctlref, struct sockaddr_ctl *sac, void **unitinfo)
{
    gDriver = new com_my_driver;
    gDriver->init();
    // just my pattern, if your driver class has connect method..
    return gDriver->connect(ctlref, sac, unitinfo);
}

static errno_t disconnect_handler(kern_ctl_ref ctlref, unsigned int unit, void *unitinfo)
{
    // just my patter, if your class has disconnect method.
    gDriver->disconnect(ctlref, unit, unitinfo);
    gDriver->release();

    return 0;
}
...
// other handlers...
extern "C" kern_return_t com_my_driver_start(kmod_info_t * ki, void *d)
{
    setup();
}
//

内核控件的官方描述为： https ://developer.apple.com/library/archive/documentation/Darwin/Conceptual/NKEConceptual/control/control.html

于 2019-07-17T04:50:59.410 回答