libubus.c

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/*
 * 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.
 */
 
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
 
#include <libubox/blob.h>
#include <libubox/blobmsg.h>
 
#include "libubus.h"
#include "libubus-internal.h"
#include "ubusmsg.h"
 
const char *__ubus_strerror[__UBUS_STATUS_LAST] = {
        [UBUS_STATUS_OK] = "Success",
        [UBUS_STATUS_INVALID_COMMAND] = "Invalid command",
        [UBUS_STATUS_INVALID_ARGUMENT] = "Invalid argument",
        [UBUS_STATUS_METHOD_NOT_FOUND] = "Method not found",
        [UBUS_STATUS_NOT_FOUND] = "Not found",
        [UBUS_STATUS_NO_DATA] = "No response",
        [UBUS_STATUS_PERMISSION_DENIED] = "Permission denied",
        [UBUS_STATUS_TIMEOUT] = "Request timed out",
        [UBUS_STATUS_NOT_SUPPORTED] = "Operation not supported",
        [UBUS_STATUS_UNKNOWN_ERROR] = "Unknown error",
        [UBUS_STATUS_CONNECTION_FAILED] = "Connection failed",
        [UBUS_STATUS_NO_MEMORY] = "Out of memory",
        [UBUS_STATUS_PARSE_ERROR] = "Parsing message data failed",
        [UBUS_STATUS_SYSTEM_ERROR] = "System error",
};
 
struct blob_buf b __hidden = {};
 
struct ubus_pending_msg {
        struct list_head list;
        struct ubus_msghdr_buf hdr;
};
 
static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
{
        const uint32_t *id1 = k1, *id2 = k2;
 
        if (*id1 < *id2)
                return -1;
        else
                return *id1 > *id2;
}
 
const char *ubus_strerror(int error)
{
        static char err[32];
 
        if (error < 0 || error >= __UBUS_STATUS_LAST)
                goto out;
 
        if (!__ubus_strerror[error])
                goto out;
 
        return __ubus_strerror[error];
 
out:
        sprintf(err, "Unknown error: %d", error);
        return err;
}
 
static void
ubus_queue_msg(struct ubus_context *ctx, struct ubus_msghdr_buf *buf)
{
        struct ubus_pending_msg *pending;
        void *data;
 
        pending = calloc_a(sizeof(*pending), &data, blob_raw_len(buf->data));
 
        pending->hdr.data = data;
        memcpy(&pending->hdr.hdr, &buf->hdr, sizeof(buf->hdr));
        memcpy(data, buf->data, blob_raw_len(buf->data));
        list_add_tail(&pending->list, &ctx->pending);
        if (ctx->sock.registered)
                uloop_timeout_set(&ctx->pending_timer, 1);
}
 
void __hidden
ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr_buf *buf, int fd)
{
        switch(buf->hdr.type) {
        case UBUS_MSG_STATUS:
        case UBUS_MSG_DATA:
                ubus_process_req_msg(ctx, buf, fd);
                break;
 
        case UBUS_MSG_INVOKE:
        case UBUS_MSG_UNSUBSCRIBE:
        case UBUS_MSG_NOTIFY:
                if (ctx->stack_depth) {
                        ubus_queue_msg(ctx, buf);
                        break;
                }
 
                ctx->stack_depth++;
                ubus_process_obj_msg(ctx, buf, fd);
                ctx->stack_depth--;
                break;
        case UBUS_MSG_MONITOR:
                if (ctx->monitor_cb)
                        ctx->monitor_cb(ctx, buf->hdr.seq, buf->data);
                break;
        }
}
 
static void ubus_process_pending_msg(struct uloop_timeout *timeout)
{
        struct ubus_context *ctx = container_of(timeout, struct ubus_context, pending_timer);
        struct ubus_pending_msg *pending;
 
        while (!list_empty(&ctx->pending)) {
                if (ctx->stack_depth)
                        break;
 
                pending = list_first_entry(&ctx->pending, struct ubus_pending_msg, list);
                list_del(&pending->list);
                ubus_process_msg(ctx, &pending->hdr, -1);
                free(pending);
        }
}
 
struct ubus_lookup_request {
        struct ubus_request req;
        ubus_lookup_handler_t cb;
};
 
static void ubus_lookup_cb(struct ubus_request *ureq, int type, struct blob_attr *msg)
{
        struct ubus_lookup_request *req;
        struct ubus_object_data obj = {};
        struct blob_attr **attr;
 
        req = container_of(ureq, struct ubus_lookup_request, req);
        attr = ubus_parse_msg(msg, blob_raw_len(msg));
 
        if (!attr[UBUS_ATTR_OBJID] || !attr[UBUS_ATTR_OBJPATH] ||
            !attr[UBUS_ATTR_OBJTYPE])
                return;
 
        obj.id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
        obj.path = blob_data(attr[UBUS_ATTR_OBJPATH]);
        obj.type_id = blob_get_u32(attr[UBUS_ATTR_OBJTYPE]);
        obj.signature = attr[UBUS_ATTR_SIGNATURE];
        req->cb(ureq->ctx, &obj, ureq->priv);
}
 
int ubus_lookup(struct ubus_context *ctx, const char *path,
                ubus_lookup_handler_t cb, void *priv)
{
        struct ubus_lookup_request lookup;
 
        blob_buf_init(&b, 0);
        if (path)
                blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 
        if (ubus_start_request(ctx, &lookup.req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        lookup.req.raw_data_cb = ubus_lookup_cb;
        lookup.req.priv = priv;
        lookup.cb = cb;
        return ubus_complete_request(ctx, &lookup.req, 0);
}
 
static void ubus_lookup_id_cb(struct ubus_request *req, int type, struct blob_attr *msg)
{
        struct blob_attr **attr;
        uint32_t *id = req->priv;
 
        attr = ubus_parse_msg(msg, blob_raw_len(msg));
 
        if (!attr[UBUS_ATTR_OBJID])
                return;
 
        *id = blob_get_u32(attr[UBUS_ATTR_OBJID]);
}
 
int ubus_lookup_id(struct ubus_context *ctx, const char *path, uint32_t *id)
{
        struct ubus_request req;
 
        blob_buf_init(&b, 0);
        if (path)
                blob_put_string(&b, UBUS_ATTR_OBJPATH, path);
 
        if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_LOOKUP, 0) < 0)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        req.raw_data_cb = ubus_lookup_id_cb;
        req.priv = id;
 
        return ubus_complete_request(ctx, &req, 0);
}
 
static int ubus_event_cb(struct ubus_context *ctx, struct ubus_object *obj,
                         struct ubus_request_data *req,
                         const char *method, struct blob_attr *msg)
{
        struct ubus_event_handler *ev;
 
        ev = container_of(obj, struct ubus_event_handler, obj);
        ev->cb(ctx, ev, method, msg);
        return 0;
}
 
static const struct ubus_method event_method = {
        .name = NULL,
        .handler = ubus_event_cb,
};
 
int ubus_register_event_handler(struct ubus_context *ctx,
                                struct ubus_event_handler *ev,
                                const char *pattern)
{
        struct ubus_object *obj = &ev->obj;
        struct blob_buf b2 = {};
        int ret;
 
        if (!obj->id) {
                obj->methods = &event_method;
                obj->n_methods = 1;
 
                if (!!obj->name ^ !!obj->type)
                        return UBUS_STATUS_INVALID_ARGUMENT;
 
                ret = ubus_add_object(ctx, obj);
                if (ret)
                        return ret;
        }
 
        /* use a second buffer, ubus_invoke() overwrites the primary one */
        blob_buf_init(&b2, 0);
        blobmsg_add_u32(&b2, "object", obj->id);
        if (pattern)
                blobmsg_add_string(&b2, "pattern", pattern);
 
        ret = ubus_invoke(ctx, UBUS_SYSTEM_OBJECT_EVENT, "register", b2.head,
                          NULL, NULL, 0);
        blob_buf_free(&b2);
 
        return ret;
}
 
int ubus_send_event(struct ubus_context *ctx, const char *id,
                    struct blob_attr *data)
{
        struct ubus_request req;
        void *s;
 
        blob_buf_init(&b, 0);
        blob_put_int32(&b, UBUS_ATTR_OBJID, UBUS_SYSTEM_OBJECT_EVENT);
        blob_put_string(&b, UBUS_ATTR_METHOD, "send");
        s = blob_nest_start(&b, UBUS_ATTR_DATA);
        blobmsg_add_string(&b, "id", id);
        blobmsg_add_field(&b, BLOBMSG_TYPE_TABLE, "data", blob_data(data), blob_len(data));
        blob_nest_end(&b, s);
 
        if (ubus_start_request(ctx, &req, b.head, UBUS_MSG_INVOKE, UBUS_SYSTEM_OBJECT_EVENT) < 0)
                return UBUS_STATUS_INVALID_ARGUMENT;
 
        return ubus_complete_request(ctx, &req, 0);
}
 
static void ubus_default_connection_lost(struct ubus_context *ctx)
{
        if (ctx->sock.registered)
                uloop_end();
}
 
int ubus_connect_ctx(struct ubus_context *ctx, const char *path)
{
        uloop_init();
        memset(ctx, 0, sizeof(*ctx));
 
        ctx->sock.fd = -1;
        ctx->sock.cb = ubus_handle_data;
        ctx->connection_lost = ubus_default_connection_lost;
        ctx->pending_timer.cb = ubus_process_pending_msg;
 
        ctx->msgbuf.data = calloc(1, UBUS_MSG_CHUNK_SIZE);
        if (!ctx->msgbuf.data)
                return -1;
        ctx->msgbuf_data_len = UBUS_MSG_CHUNK_SIZE;
 
        INIT_LIST_HEAD(&ctx->requests);
        INIT_LIST_HEAD(&ctx->pending);
        INIT_LIST_HEAD(&ctx->auto_subscribers);
        avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
        if (ubus_reconnect(ctx, path)) {
                free(ctx->msgbuf.data);
                ctx->msgbuf.data = NULL;
                return -1;
        }
 
        return 0;
}
 
static void ubus_auto_reconnect_cb(struct uloop_timeout *timeout)
{
        struct ubus_auto_conn *conn = container_of(timeout, struct ubus_auto_conn, timer);
 
        if (!ubus_reconnect(&conn->ctx, conn->path))
                ubus_add_uloop(&conn->ctx);
        else
                uloop_timeout_set(timeout, 1000);
}
 
static void ubus_auto_disconnect_cb(struct ubus_context *ctx)
{
        struct ubus_auto_conn *conn = container_of(ctx, struct ubus_auto_conn, ctx);
 
        conn->timer.cb = ubus_auto_reconnect_cb;
        uloop_timeout_set(&conn->timer, 1000);
}
 
static void ubus_auto_connect_cb(struct uloop_timeout *timeout)
{
        struct ubus_auto_conn *conn = container_of(timeout, struct ubus_auto_conn, timer);
 
        if (ubus_connect_ctx(&conn->ctx, conn->path)) {
                uloop_timeout_set(timeout, 1000);
                fprintf(stderr, "failed to connect to ubus\n");
                return;
        }
        conn->ctx.connection_lost = ubus_auto_disconnect_cb;
        if (conn->cb)
                conn->cb(&conn->ctx);
        ubus_add_uloop(&conn->ctx);
}
 
void ubus_auto_connect(struct ubus_auto_conn *conn)
{
        conn->timer.cb = ubus_auto_connect_cb;
        ubus_auto_connect_cb(&conn->timer);
}
 
struct ubus_context *ubus_connect(const char *path)
{
        struct ubus_context *ctx;
 
        ctx = calloc(1, sizeof(*ctx));
        if (!ctx)
                return NULL;
 
        if (ubus_connect_ctx(ctx, path)) {
                free(ctx);
                ctx = NULL;
        }
 
        return ctx;
}
 
void ubus_shutdown(struct ubus_context *ctx)
{
        blob_buf_free(&b);
        if (!ctx)
                return;
        uloop_fd_delete(&ctx->sock);
        close(ctx->sock.fd);
        uloop_timeout_cancel(&ctx->pending_timer);
        free(ctx->msgbuf.data);
}
 
void ubus_free(struct ubus_context *ctx)
{
        ubus_shutdown(ctx);
        free(ctx);
}