android binder机制实现

#define BINDER_SET_CONTEXT_MGR _IOW('b', 7, int)

#define BINDER_THREAD_EXIT _IOW('b', 8, int)

#define BINDER_VERSION _IOWR('b', 9, struct binder_version)

#define BINDER_WRITE_READ _IOWR('b', 1, struct binder_write_read) #define BINDER_SET_IDLE_TIMEOUT _IOW('b', 3, int64_t) #define BINDER_SET_MAX_THREADS _IOW('b', 5, size_t) #define BINDER_SET_IDLE_PRIORITY _IOW('b', 6, int) #define BINDER_SET_CONTEXT_MGR _IOW('b', 7, int) #define BINDER_THREAD_EXIT _IOW('b', 8, int) #define BINDER_VERSION _IOWR('b', 9, struct binder_version)

BR_XXX等宏为BinderDriverReturnProtocol，表示Binder驱动返回协议。

BC_XXX等宏为BinderDriverCommandProtocol，表示Binder驱动命令协议。

binder_thread是Binder驱动程序中使用的另外一个重要的数据结构，数据结构的定义如下所示：

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struct binder_thread {

struct binder_proc *proc;

struct rb_node rb_node;

int pid;

int looper;

struct binder_transaction *transaction_stack;

struct list_head todo;

uint32_t return_error;

uint32_t return_error2;

wait_queue_head_t wait;

struct binder_stats stats;

};

struct binder_thread { struct binder_proc *proc; struct rb_node rb_node; int pid; int looper; struct binder_transaction *transaction_stack; struct list_head todo; uint32_t return_error; uint32_t return_error2; wait_queue_head_t wait; struct binder_stats stats; };

binder_thread 的各个成员信息是从rb_node中得出。

BINDER_WRITE_READ是最重要的ioctl，它使用一个数据结构binder_write_read定义读写的数据。

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