binder.h

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/*
 * Copyright (C) 2008 Google, Inc.
 *
 * Based on, but no longer compatible with, the original
 * OpenBinder.org binder driver interface, which is:
 *
 * Copyright (c) 2005 Palmsource, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#ifndef _LINUX_BINDER_H
#define _LINUX_BINDER_H

#include <linux/ioctl.h>

#define B_PACK_CHARS(c1, c2, c3, c4) \
    ((((c1)<<24)) | (((c2)<<16)) | (((c3)<<8)) | (c4))
#define B_TYPE_LARGE 0x85

enum {
    BINDER_TYPE_BINDER  = B_PACK_CHARS('s', 'b', '*', B_TYPE_LARGE),
    BINDER_TYPE_WEAK_BINDER = B_PACK_CHARS('w', 'b', '*', B_TYPE_LARGE),
    BINDER_TYPE_HANDLE  = B_PACK_CHARS('s', 'h', '*', B_TYPE_LARGE),
    BINDER_TYPE_WEAK_HANDLE = B_PACK_CHARS('w', 'h', '*', B_TYPE_LARGE),
    BINDER_TYPE_FD      = B_PACK_CHARS('f', 'd', '*', B_TYPE_LARGE),
};

enum {
    FLAT_BINDER_FLAG_PRIORITY_MASK = 0xff,
    FLAT_BINDER_FLAG_ACCEPTS_FDS = 0x100,
};

/*
 * This is the flattened representation of a Binder object for transfer
 * between processes.  The 'offsets' supplied as part of a binder transaction
 * contains offsets into the data where these structures occur.  The Binder
 * driver takes care of re-writing the structure type and data as it moves
 * between processes.
 */
struct flat_binder_object {
    /* 8 bytes for large_flat_header. */
    unsigned long       type;
    unsigned long       flags;

    /* 8 bytes of data. */
    union {
        void __user *binder;    /* local object */
        signed long handle;     /* remote object */
    };

    /* extra data associated with local object */
    void __user     *cookie;
};

/*
 * On 64-bit platforms where user code may run in 32-bits the driver must
 * translate the buffer (and local binder) addresses appropriately.
 */

struct binder_write_read {
    signed long write_size; /* bytes to write */
    signed long write_consumed; /* bytes consumed by driver */
    unsigned long   write_buffer;
    signed long read_size;  /* bytes to read */
    signed long read_consumed;  /* bytes consumed by driver */
    unsigned long   read_buffer;
};

/* Use with BINDER_VERSION, driver fills in fields. */
struct binder_version {
    /* driver protocol version -- increment with incompatible change */
    signed long protocol_version;
};

/* This is the current protocol version. */
#define BINDER_CURRENT_PROTOCOL_VERSION 7

#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)

/*
 * NOTE: Two special error codes you should check for when calling
 * in to the driver are:
 *
 * EINTR -- The operation has been interupted.  This should be
 * handled by retrying the ioctl() until a different error code
 * is returned.
 *
 * ECONNREFUSED -- The driver is no longer accepting operations
 * from your process.  That is, the process is being destroyed.
 * You should handle this by exiting from your process.  Note
 * that once this error code is returned, all further calls to
 * the driver from any thread will return this same code.
 */

enum transaction_flags {
    TF_ONE_WAY  = 0x01, /* this is a one-way call: async, no return */
    TF_ROOT_OBJECT  = 0x04, /* contents are the component's root object */
    TF_STATUS_CODE  = 0x08, /* contents are a 32-bit status code */
    TF_ACCEPT_FDS   = 0x10, /* allow replies with file descriptors */
};

struct binder_transaction_data {
    /* The first two are only used for bcTRANSACTION and brTRANSACTION,
     * identifying the target and contents of the transaction.
     */
    union {
        size_t  handle; /* target descriptor of command transaction */
        void    *ptr;   /* target descriptor of return transaction */
    } target;
    void        *cookie;    /* target object cookie */
    unsigned int    code;       /* transaction command */

    /* General information about the transaction. */
    unsigned int    flags;
    pid_t       sender_pid;
    uid_t       sender_euid;
    size_t      data_size;  /* number of bytes of data */
    size_t      offsets_size;   /* number of bytes of offsets */

    /* If this transaction is inline, the data immediately
     * follows here; otherwise, it ends with a pointer to
     * the data buffer.
     */
    union {
        struct {
            /* transaction data */
            const void __user   *buffer;
            /* offsets from buffer to flat_binder_object structs */
            const void __user   *offsets;
        } ptr;
        uint8_t buf[8];
    } data;
};

struct binder_ptr_cookie {
    void *ptr;
    void *cookie;
};

struct binder_pri_desc {
    int priority;
    int desc;
};

struct binder_pri_ptr_cookie {
    int priority;
    void *ptr;
    void *cookie;
};

enum BinderDriverReturnProtocol {
    BR_ERROR = _IOR('r', 0, int),
    /*
     * int: error code
     */

    BR_OK = _IO('r', 1),
    /* No parameters! */

    BR_TRANSACTION = _IOR('r', 2, struct binder_transaction_data),
    BR_REPLY = _IOR('r', 3, struct binder_transaction_data),
    /*
     * binder_transaction_data: the received command.
     */

    BR_ACQUIRE_RESULT = _IOR('r', 4, int),
    /*
     * not currently supported
     * int: 0 if the last bcATTEMPT_ACQUIRE was not successful.
     * Else the remote object has acquired a primary reference.
     */

    BR_DEAD_REPLY = _IO('r', 5),
    /*
     * The target of the last transaction (either a bcTRANSACTION or
     * a bcATTEMPT_ACQUIRE) is no longer with us.  No parameters.
     */

    BR_TRANSACTION_COMPLETE = _IO('r', 6),
    /*
     * No parameters... always refers to the last transaction requested
     * (including replies).  Note that this will be sent even for
     * asynchronous transactions.
     */

    BR_INCREFS = _IOR('r', 7, struct binder_ptr_cookie),
    BR_ACQUIRE = _IOR('r', 8, struct binder_ptr_cookie),
    BR_RELEASE = _IOR('r', 9, struct binder_ptr_cookie),
    BR_DECREFS = _IOR('r', 10, struct binder_ptr_cookie),
    /*
     * void *:  ptr to binder
     * void *: cookie for binder
     */

    BR_ATTEMPT_ACQUIRE = _IOR('r', 11, struct binder_pri_ptr_cookie),
    /*
     * not currently supported
     * int: priority
     * void *: ptr to binder
     * void *: cookie for binder
     */

    BR_NOOP = _IO('r', 12),
    /*
     * No parameters.  Do nothing and examine the next command.  It exists
     * primarily so that we can replace it with a BR_SPAWN_LOOPER command.
     */

    BR_SPAWN_LOOPER = _IO('r', 13),
    /*
     * No parameters.  The driver has determined that a process has no
     * threads waiting to service incomming transactions.  When a process
     * receives this command, it must spawn a new service thread and
     * register it via bcENTER_LOOPER.
     */

    BR_FINISHED = _IO('r', 14),
    /*
     * not currently supported
     * stop threadpool thread
     */

    BR_DEAD_BINDER = _IOR('r', 15, void *),
    /*
     * void *: cookie
     */
    BR_CLEAR_DEATH_NOTIFICATION_DONE = _IOR('r', 16, void *),
    /*
     * void *: cookie
     */

    BR_FAILED_REPLY = _IO('r', 17),
    /*
     * The the last transaction (either a bcTRANSACTION or
     * a bcATTEMPT_ACQUIRE) failed (e.g. out of memory).  No parameters.
     */
};

enum BinderDriverCommandProtocol {
    BC_TRANSACTION = _IOW('c', 0, struct binder_transaction_data),
    BC_REPLY = _IOW('c', 1, struct binder_transaction_data),
    /*
     * binder_transaction_data: the sent command.
     */

    BC_ACQUIRE_RESULT = _IOW('c', 2, int),
    /*
     * not currently supported
     * int:  0 if the last BR_ATTEMPT_ACQUIRE was not successful.
     * Else you have acquired a primary reference on the object.
     */

    BC_FREE_BUFFER = _IOW('c', 3, int),
    /*
     * void *: ptr to transaction data received on a read
     */

    BC_INCREFS = _IOW('c', 4, int),
    BC_ACQUIRE = _IOW('c', 5, int),
    BC_RELEASE = _IOW('c', 6, int),
    BC_DECREFS = _IOW('c', 7, int),
    /*
     * int: descriptor
     */

    BC_INCREFS_DONE = _IOW('c', 8, struct binder_ptr_cookie),
    BC_ACQUIRE_DONE = _IOW('c', 9, struct binder_ptr_cookie),
    /*
     * void *: ptr to binder
     * void *: cookie for binder
     */

    BC_ATTEMPT_ACQUIRE = _IOW('c', 10, struct binder_pri_desc),
    /*
     * not currently supported
     * int: priority
     * int: descriptor
     */

    BC_REGISTER_LOOPER = _IO('c', 11),
    /*
     * No parameters.
     * Register a spawned looper thread with the device.
     */

    BC_ENTER_LOOPER = _IO('c', 12),
    BC_EXIT_LOOPER = _IO('c', 13),
    /*
     * No parameters.
     * These two commands are sent as an application-level thread
     * enters and exits the binder loop, respectively.  They are
     * used so the binder can have an accurate count of the number
     * of looping threads it has available.
     */

    BC_REQUEST_DEATH_NOTIFICATION = _IOW('c', 14, struct binder_ptr_cookie),
    /*
     * void *: ptr to binder
     * void *: cookie
     */

    BC_CLEAR_DEATH_NOTIFICATION = _IOW('c', 15, struct binder_ptr_cookie),
    /*
     * void *: ptr to binder
     * void *: cookie
     */

    BC_DEAD_BINDER_DONE = _IOW('c', 16, void *),
    /*
     * void *: cookie
     */
};

#endif /* _LINUX_BINDER_H */