libubus-req.c

/*
 * 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 <unistd.h>
#include "libubus.h"
#include "libubus-internal.h"

struct ubus_pending_data {
    struct list_head list;
    int type;
    struct blob_attr data[];
};

static void req_data_cb(struct ubus_request *req, int type, struct blob_attr *data)
{
    struct blob_attr **attr;

    if (req->raw_data_cb)
        req->raw_data_cb(req, type, data);

    if (!req->data_cb)
        return;

    attr = ubus_parse_msg(data);
    req->data_cb(req, type, attr[UBUS_ATTR_DATA]);
}

static void __ubus_process_req_data(struct ubus_request *req)
{
    struct ubus_pending_data *data;

    while (!list_empty(&req->pending)) {
        data = list_first_entry(&req->pending,
            struct ubus_pending_data, list);
        list_del(&data->list);
        if (!req->cancelled)
            req_data_cb(req, data->type, data->data);
        free(data);
    }
}

int __hidden ubus_start_request(struct ubus_context *ctx, struct ubus_request *req,
                struct blob_attr *msg, int cmd, uint32_t peer)
{
    memset(req, 0, sizeof(*req));

    if (msg && blob_pad_len(msg) > UBUS_MAX_MSGLEN)
        return -1;

    INIT_LIST_HEAD(&req->list);
    INIT_LIST_HEAD(&req->pending);
    req->ctx = ctx;
    req->peer = peer;
    req->seq = ++ctx->request_seq;
    return ubus_send_msg(ctx, req->seq, msg, cmd, peer, -1);
}

void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
{
    if (list_empty(&req->list))
        return;

    req->cancelled = true;
    __ubus_process_req_data(req);
    list_del_init(&req->list);
}

void ubus_complete_request_async(struct ubus_context *ctx, struct ubus_request *req)
{
    if (!list_empty(&req->list))
        return;

    list_add(&req->list, &ctx->requests);
}

static void
ubus_req_complete_cb(struct ubus_request *req)
{
    ubus_complete_handler_t cb = req->complete_cb;

    if (!cb)
        return;

    req->complete_cb = NULL;
    cb(req, req->status_code);
}

static void
ubus_set_req_status(struct ubus_request *req, int ret)
{
    if (!list_empty(&req->list))
        list_del_init(&req->list);

    req->status_msg = true;
    req->status_code = ret;
    if (!req->blocked)
        ubus_req_complete_cb(req);
}

static void ubus_sync_req_cb(struct ubus_request *req, int ret)
{
    req->status_msg = true;
    req->status_code = ret;
    uloop_end();
}

static int64_t get_time_msec(void)
{
    struct timespec ts;
    int64_t val;

    clock_gettime(CLOCK_MONOTONIC, &ts);
    val = (int64_t) ts.tv_sec * 1000LL;
    val += ts.tv_nsec / 1000000LL;
    return val;
}

int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
              int req_timeout)
{
    ubus_complete_handler_t complete_cb = req->complete_cb;
    bool registered = ctx->sock.registered;
    int status = UBUS_STATUS_NO_DATA;
    int64_t timeout = 0, time_end = 0;

    if (!registered) {
        uloop_init();
        ubus_add_uloop(ctx);
    }

    if (req_timeout)
        time_end = get_time_msec() + req_timeout;

    ubus_complete_request_async(ctx, req);
    req->complete_cb = ubus_sync_req_cb;

    ctx->stack_depth++;
    while (!req->status_msg) {
        bool cancelled = uloop_cancelled;

        uloop_cancelled = false;
        if (req_timeout) {
            timeout = time_end - get_time_msec();
            if (timeout <= 0) {
                ubus_set_req_status(req, UBUS_STATUS_TIMEOUT);
                uloop_cancelled = cancelled;
                break;
            }
        }
        ubus_poll_data(ctx, (unsigned int) timeout);

        uloop_cancelled = cancelled;
    }
    ctx->stack_depth--;
    if (ctx->stack_depth)
        uloop_cancelled = true;

    if (req->status_msg)
        status = req->status_code;

    req->complete_cb = complete_cb;
    if (req->complete_cb)
        req->complete_cb(req, status);

    if (!registered) {
        uloop_fd_delete(&ctx->sock);

        if (!ctx->stack_depth)
            ctx->pending_timer.cb(&ctx->pending_timer);
    }

    return status;
}

void ubus_complete_deferred_request(struct ubus_context *ctx, struct ubus_request_data *req, int ret)
{
    blob_buf_init(&b, 0);
    blob_put_int32(&b, UBUS_ATTR_STATUS, ret);
    blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
    ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_STATUS, req->peer, req->fd);
}

int ubus_send_reply(struct ubus_context *ctx, struct ubus_request_data *req,
            struct blob_attr *msg)
{
    int ret;

    blob_buf_init(&b, 0);
    blob_put_int32(&b, UBUS_ATTR_OBJID, req->object);
    blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));
    ret = ubus_send_msg(ctx, req->seq, b.head, UBUS_MSG_DATA, req->peer, -1);
    if (ret < 0)
        return UBUS_STATUS_NO_DATA;

    return 0;
}

int ubus_invoke_async(struct ubus_context *ctx, uint32_t obj, const char *method,
                       struct blob_attr *msg, struct ubus_request *req)
{
    blob_buf_init(&b, 0);
    blob_put_int32(&b, UBUS_ATTR_OBJID, obj);
    blob_put_string(&b, UBUS_ATTR_METHOD, method);
    if (msg)
        blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));

    if (ubus_start_request(ctx, req, b.head, UBUS_MSG_INVOKE, obj) < 0)
        return UBUS_STATUS_INVALID_ARGUMENT;

    return 0;
}

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)
{
    struct ubus_request req;
    int rc;

    rc = ubus_invoke_async(ctx, obj, method, msg, &req);
    if (rc)
        return rc;

    req.data_cb = cb;
    req.priv = priv;
    return ubus_complete_request(ctx, &req, timeout);
}

static void
ubus_notify_complete_cb(struct ubus_request *req, int ret)
{
    struct ubus_notify_request *nreq;

    nreq = container_of(req, struct ubus_notify_request, req);
    if (!nreq->complete_cb)
        return;

    nreq->complete_cb(nreq, 0, 0);
}

static int
__ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,
            const char *type, struct blob_attr *msg,
            struct ubus_notify_request *req, bool reply)
{
    memset(req, 0, sizeof(*req));

    blob_buf_init(&b, 0);
    blob_put_int32(&b, UBUS_ATTR_OBJID, obj->id);
    blob_put_string(&b, UBUS_ATTR_METHOD, type);

    if (!reply)
        blob_put_int8(&b, UBUS_ATTR_NO_REPLY, true);

    if (msg)
        blob_put(&b, UBUS_ATTR_DATA, blob_data(msg), blob_len(msg));

    if (ubus_start_request(ctx, &req->req, b.head, UBUS_MSG_NOTIFY, obj->id) < 0)
        return UBUS_STATUS_INVALID_ARGUMENT;

    /* wait for status message from ubusd first */
    req->req.notify = true;
    req->pending = 1;
    req->id[0] = obj->id;
    req->req.complete_cb = ubus_notify_complete_cb;

    return 0;
}

int ubus_notify_async(struct ubus_context *ctx, struct ubus_object *obj,
              const char *type, struct blob_attr *msg,
              struct ubus_notify_request *req)
{
    return __ubus_notify_async(ctx, obj, type, msg, req, true);
}

int ubus_notify(struct ubus_context *ctx, struct ubus_object *obj,
        const char *type, struct blob_attr *msg, int timeout)
{
    struct ubus_notify_request req;
    int ret;

    ret = __ubus_notify_async(ctx, obj, type, msg, &req, timeout >= 0);
    if (ret < 0)
        return ret;

    if (timeout < 0) {
        ubus_abort_request(ctx, &req.req);
        return 0;
    }

    return ubus_complete_request(ctx, &req.req, timeout);
}

static bool ubus_get_status(struct ubus_msghdr_buf *buf, int *ret)
{
    struct blob_attr **attrbuf = ubus_parse_msg(buf->data);

    if (!attrbuf[UBUS_ATTR_STATUS])
        return false;

    *ret = blob_get_u32(attrbuf[UBUS_ATTR_STATUS]);
    return true;
}

static int
ubus_process_req_status(struct ubus_request *req, struct ubus_msghdr_buf *buf)
{
    int ret = UBUS_STATUS_INVALID_ARGUMENT;

    ubus_get_status(buf, &ret);
    req->peer = buf->hdr.peer;
    ubus_set_req_status(req, ret);

    return ret;
}

static void
ubus_process_req_data(struct ubus_request *req, struct ubus_msghdr_buf *buf)
{
    struct ubus_pending_data *data;
    int len;

    if (!req->blocked) {
        req->blocked = true;
        req_data_cb(req, buf->hdr.type, buf->data);
        __ubus_process_req_data(req);
        req->blocked = false;

        if (req->status_msg)
            ubus_req_complete_cb(req);

        return;
    }

    len = blob_raw_len(buf->data);
    data = calloc(1, sizeof(*data) + len);
    if (!data)
        return;

    data->type = buf->hdr.type;
    memcpy(data->data, buf->data, len);
    list_add(&data->list, &req->pending);
}

static int
ubus_find_notify_id(struct ubus_notify_request *n, uint32_t objid)
{
    uint32_t pending = n->pending;
    int i;

    for (i = 0; pending; i++, pending >>= 1) {
        if (!(pending & 1))
            continue;

        if (n->id[i] == objid)
            return i;
    }

    return -1;
}

static struct ubus_request *
ubus_find_request(struct ubus_context *ctx, uint32_t seq, uint32_t peer, int *id)
{
    struct ubus_request *req;

    list_for_each_entry(req, &ctx->requests, list) {
        struct ubus_notify_request *nreq;
        nreq = container_of(req, struct ubus_notify_request, req);

        if (seq != req->seq)
            continue;

        if (req->notify) {
            if (!nreq->pending)
                continue;

            *id = ubus_find_notify_id(nreq, peer);
            if (*id < 0)
                continue;
        } else if (peer != req->peer)
            continue;

        return req;
    }
    return NULL;
}

static void ubus_process_notify_status(struct ubus_request *req, int id, struct ubus_msghdr_buf *buf)
{
    struct ubus_notify_request *nreq;
    struct blob_attr **tb;
    struct blob_attr *cur;
    int rem, idx = 1;
    int ret = 0;

    nreq = container_of(req, struct ubus_notify_request, req);
    nreq->pending &= ~(1 << id);

    if (!id) {
        /* first id: ubusd's status message with a list of ids */
        tb = ubus_parse_msg(buf->data);
        if (tb[UBUS_ATTR_SUBSCRIBERS]) {
            blob_for_each_attr(cur, tb[UBUS_ATTR_SUBSCRIBERS], rem) {
                if (!blob_check_type(blob_data(cur), blob_len(cur), BLOB_ATTR_INT32))
                    continue;

                nreq->pending |= (1 << idx);
                nreq->id[idx] = blob_get_int32(cur);
                idx++;

                if (idx == UBUS_MAX_NOTIFY_PEERS + 1)
                    break;
            }
        }
    } else {
        ubus_get_status(buf, &ret);
        if (nreq->status_cb)
            nreq->status_cb(nreq, id, ret);
    }

    if (!nreq->pending)
        ubus_set_req_status(req, 0);
}

void __hidden ubus_process_req_msg(struct ubus_context *ctx, struct ubus_msghdr_buf *buf, int fd)
{
    struct ubus_msghdr *hdr = &buf->hdr;
    struct ubus_request *req;
    int id = -1;

    switch(hdr->type) {
    case UBUS_MSG_STATUS:
        req = ubus_find_request(ctx, hdr->seq, hdr->peer, &id);
        if (!req)
            break;

        if (fd >= 0) {
            if (req->fd_cb)
                req->fd_cb(req, fd);
            else
                close(fd);
        }

        if (id >= 0)
            ubus_process_notify_status(req, id, buf);
        else
            ubus_process_req_status(req, buf);
        break;

    case UBUS_MSG_DATA:
        req = ubus_find_request(ctx, hdr->seq, hdr->peer, &id);
        if (req && (req->data_cb || req->raw_data_cb))
            ubus_process_req_data(req, buf);
        break;
    }
}