libubus.h

/*
 * Copyright (C) 2011-2014 Felix Fietkau <nbd@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation
 *
 * 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 __LIBUBUS_H
#define __LIBUBUS_H

#include <libubox/avl.h>
#include <libubox/list.h>
#include <libubox/blobmsg.h>
#include <libubox/uloop.h>
#include <stdint.h>
#include "ubusmsg.h"
#include "ubus_common.h"

#define UBUS_MAX_NOTIFY_PEERS    16

struct ubus_context;
struct ubus_msg_src;
struct ubus_object;
struct ubus_request;
struct ubus_request_data;
struct ubus_object_data;
struct ubus_event_handler;
struct ubus_subscriber;
struct ubus_notify_request;

struct ubus_msghdr_buf {
    struct ubus_msghdr hdr;
    struct blob_attr *data;
};

typedef void (*ubus_lookup_handler_t)(struct ubus_context *ctx,
                      struct ubus_object_data *obj,
                      void *priv);
typedef int (*ubus_handler_t)(struct ubus_context *ctx, struct ubus_object *obj,
                  struct ubus_request_data *req,
                  const char *method, struct blob_attr *msg);
typedef void (*ubus_state_handler_t)(struct ubus_context *ctx, struct ubus_object *obj);
typedef void (*ubus_remove_handler_t)(struct ubus_context *ctx,
                      struct ubus_subscriber *obj, uint32_t id);
typedef void (*ubus_event_handler_t)(struct ubus_context *ctx, struct ubus_event_handler *ev,
                     const char *type, struct blob_attr *msg);
typedef void (*ubus_data_handler_t)(struct ubus_request *req,
                    int type, struct blob_attr *msg);
typedef void (*ubus_fd_handler_t)(struct ubus_request *req, int fd);
typedef void (*ubus_complete_handler_t)(struct ubus_request *req, int ret);
typedef void (*ubus_notify_complete_handler_t)(struct ubus_notify_request *req,
                           int idx, int ret);
typedef void (*ubus_connect_handler_t)(struct ubus_context *ctx);

#define UBUS_OBJECT_TYPE(_name, _methods)        \
    {                        \
        .name = _name,                \
        .id = 0,                \
        .n_methods = ARRAY_SIZE(_methods),    \
        .methods = _methods            \
    }

#define __UBUS_METHOD_NOARG(_name, _handler)        \
    .name = _name,                    \
    .handler = _handler

#define __UBUS_METHOD(_name, _handler, _policy)        \
    __UBUS_METHOD_NOARG(_name, _handler),        \
    .policy = _policy,                \
    .n_policy = ARRAY_SIZE(_policy)

#define UBUS_METHOD(_name, _handler, _policy)        \
    { __UBUS_METHOD(_name, _handler, _policy) }

#define UBUS_METHOD_MASK(_name, _handler, _policy, _mask) \
    {                        \
        __UBUS_METHOD(_name, _handler, _policy),\
        .mask = _mask                \
    }

#define UBUS_METHOD_NOARG(_name, _handler)        \
    { __UBUS_METHOD_NOARG(_name, _handler) }

struct ubus_method {
    const char *name;
    ubus_handler_t handler;

    unsigned long mask;
    const struct blobmsg_policy *policy;
    int n_policy;
};

struct ubus_object_type {
    const char *name;
    uint32_t id;

    const struct ubus_method *methods;
    int n_methods;
};

struct ubus_object {
    struct avl_node avl;

    const char *name;
    uint32_t id;

    const char *path;
    struct ubus_object_type *type;

    ubus_state_handler_t subscribe_cb;
    bool has_subscribers;

    const struct ubus_method *methods;
    int n_methods;
};

struct ubus_subscriber {
    struct ubus_object obj;

    ubus_handler_t cb;
    ubus_remove_handler_t remove_cb;
};

struct ubus_event_handler {
    struct ubus_object obj;

    ubus_event_handler_t cb;
};

struct ubus_context {
    struct list_head requests;
    struct avl_tree objects;
    struct list_head pending;

    struct uloop_fd sock;
    struct uloop_timeout pending_timer;

    uint32_t local_id;
    uint16_t request_seq;
    int stack_depth;

    void (*connection_lost)(struct ubus_context *ctx);

    struct ubus_msghdr_buf msgbuf;
    uint32_t msgbuf_data_len;
    int msgbuf_reduction_counter;
};

struct ubus_object_data {
    uint32_t id;
    uint32_t type_id;
    const char *path;
    struct blob_attr *signature;
};

struct ubus_request_data {
    uint32_t object;
    uint32_t peer;
    uint16_t seq;

    /* internal use */
    bool deferred;
    int fd;
};

struct ubus_request {
    struct list_head list;

    struct list_head pending;
    int status_code;
    bool status_msg;
    bool blocked;
    bool cancelled;
    bool notify;

    uint32_t peer;
    uint16_t seq;

    ubus_data_handler_t raw_data_cb;
    ubus_data_handler_t data_cb;
    ubus_fd_handler_t fd_cb;
    ubus_complete_handler_t complete_cb;

    struct ubus_context *ctx;
    void *priv;
};

struct ubus_notify_request {
    struct ubus_request req;

    ubus_notify_complete_handler_t status_cb;
    ubus_notify_complete_handler_t complete_cb;

    uint32_t pending;
    uint32_t id[UBUS_MAX_NOTIFY_PEERS + 1];
};

struct ubus_auto_conn {
    struct ubus_context ctx;
    struct uloop_timeout timer;
    const char *path;
    ubus_connect_handler_t cb;
};

struct ubus_context *ubus_connect(const char *path);
int ubus_connect_ctx(struct ubus_context *ctx, const char *path);
void ubus_auto_connect(struct ubus_auto_conn *conn);
int ubus_reconnect(struct ubus_context *ctx, const char *path);

/* call this only for struct ubus_context pointers returned by ubus_connect() */
void ubus_free(struct ubus_context *ctx);

/* call this only for struct ubus_context pointers initialised by ubus_connect_ctx() */
void ubus_shutdown(struct ubus_context *ctx);

const char *ubus_strerror(int error);

static inline void ubus_add_uloop(struct ubus_context *ctx)
{
    uloop_fd_add(&ctx->sock, ULOOP_BLOCKING | ULOOP_READ);
}

/* call this for read events on ctx->sock.fd when not using uloop */
static inline void ubus_handle_event(struct ubus_context *ctx)
{
    ctx->sock.cb(&ctx->sock, ULOOP_READ);
}

/* ----------- raw request handling ----------- */

/* wait for a request to complete and return its status */
int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
              int timeout);

/* complete a request asynchronously */
void ubus_complete_request_async(struct ubus_context *ctx,
                 struct ubus_request *req);

/* abort an asynchronous request */
void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req);

/* ----------- objects ----------- */

int ubus_lookup(struct ubus_context *ctx, const char *path,
        ubus_lookup_handler_t cb, void *priv);

int ubus_lookup_id(struct ubus_context *ctx, const char *path, uint32_t *id);

/* make an object visible to remote connections */
int ubus_add_object(struct ubus_context *ctx, struct ubus_object *obj);

/* remove the object from the ubus connection */
int ubus_remove_object(struct ubus_context *ctx, struct ubus_object *obj);

/* add a subscriber notifications from another object */
int ubus_register_subscriber(struct ubus_context *ctx, struct ubus_subscriber *obj);

static inline int
ubus_unregister_subscriber(struct ubus_context *ctx, struct ubus_subscriber *obj)
{
    return ubus_remove_object(ctx, &obj->obj);
}

int ubus_subscribe(struct ubus_context *ctx, struct ubus_subscriber *obj, uint32_t id);
int ubus_unsubscribe(struct ubus_context *ctx, struct ubus_subscriber *obj, uint32_t id);

/* ----------- rpc ----------- */

/* invoke a method on a specific object */
int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
        struct blob_attr *msg, ubus_data_handler_t cb, void *priv,
        int timeout);

/* asynchronous version of ubus_invoke() */
int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
              struct blob_attr *msg, struct ubus_request *req);

/* send a reply to an incoming object method call */
int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
            struct blob_attr *msg);

static inline void ubus_defer_request(struct ubus_context *ctx,
                      struct ubus_request_data *req,
                      struct ubus_request_data *new_req)
{
    memcpy(new_req, req, sizeof(*req));
    req->deferred = true;
}

static inline void ubus_request_set_fd(struct ubus_context *ctx,
                       struct ubus_request_data *req, int fd)
{
    req->fd = fd;
}

void ubus_complete_deferred_request(struct ubus_context *ctx,
                    struct ubus_request_data *req, int ret);

/*
 * send a notification to all subscribers of an object
 * if timeout < 0, no reply is expected from subscribers
 */
int ubus_notify(struct ubus_context *ctx, struct ubus_object *obj,
        const char *type, struct blob_attr *msg, int timeout);

int ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,
              const char *type, struct blob_attr *msg,
              struct ubus_notify_request *req);


/* ----------- events ----------- */

int ubus_send_event(struct ubus_context *ctx, const char *id,
            struct blob_attr *data);

int ubus_register_event_handler(struct ubus_context *ctx,
                struct ubus_event_handler *ev,
                const char *pattern);

static inline int ubus_unregister_event_handler(struct ubus_context *ctx,
                        struct ubus_event_handler *ev)
{
    return ubus_remove_object(ctx, &ev->obj);
}

#endif