ubus.c

/* SPDX-License-Identifier: MIT */
/*
 * Author: Jianhui Zhao <zhaojh329@gmail.com>
 */

#include <libubus.h>
#include <fcntl.h>
#include <math.h>

#include "eco.h"

struct eco_ubus_context {
    struct eco_context *eco;
    struct ubus_context ctx;
    struct ev_timer tmr;
    struct ev_io io;
    struct {
        struct ubus_request req;
        struct ev_timer tmr;
        lua_State *L;
        bool has_data;
        double timeout;
    } req;
    char *path;
    char path_data[0];
};

struct eco_ubus_object {
    struct ubus_object object;
    struct ubus_object_type type;
    struct ubus_method methods[0];
};

#define ECO_UBUS_CTX_MT "eco{ubus-ctx}"

static const char *obj_registry = "eco.ubus{obj}";

static void lua_push_ubus_ctx(lua_State *L, struct eco_ubus_context *ctx)
{
    lua_rawgetp(L, LUA_REGISTRYINDEX, &obj_registry);
    lua_rawgetp(L, -1, ctx);
    lua_remove(L, -2);
}

static void lua_table_to_blob(lua_State *L, int index, struct blob_buf *b, bool is_array)
{
    void *c;

    if (!lua_istable(L, index))
        return;

    for (lua_pushnil(L); lua_next(L, index); lua_pop(L, 2)) {
        const char *key;
        int type;

        lua_pushvalue(L, -2);
        lua_insert(L, -2);

        key = is_array ? NULL : lua_tostring(L, -2);

        type = lua_type(L, -1);

        switch (type) {
        case LUA_TBOOLEAN:
            blobmsg_add_u8(b, key, (uint8_t)lua_toboolean(L, -1));
            break;

        case LUA_TNUMBER: {
            if (lua_isinteger(L, -1)) {
                int64_t v = lua_tointeger(L, -1);
                if (v > INT32_MAX)
                    blobmsg_add_u64(b, key, v);
                else
                    blobmsg_add_u32(b, key, v);
            } else {
                blobmsg_add_double(b, key, lua_tonumber(L, -1));
            }
            break;
        }

        case LUA_TSTRING:
        case LUA_TUSERDATA:
        case LUA_TLIGHTUSERDATA:
            if (type == LUA_TSTRING) {
                blobmsg_add_string(b, key, lua_tostring(L, -1));
            } else {
                const char *val = lua_tostring(L, -1);
                if (val)
                    blobmsg_add_string(b, key, val);
            }
            break;

        case LUA_TTABLE:
            if (lua_table_is_array(L, -1)) {
                c = blobmsg_open_array(b, key);
                lua_table_to_blob(L, lua_gettop(L), b, true);
                blobmsg_close_array(b, c);
            } else {
                c = blobmsg_open_table(b, key);
                lua_table_to_blob(L, lua_gettop(L), b, false);
                blobmsg_close_table(b, c);
            }
            break;
        }
    }
}

static void blob_to_lua_table(lua_State *L, struct blob_attr *attr, size_t len, bool is_array);

static int __blob_to_lua_table(lua_State *L, struct blob_attr *attr, bool is_array)
{
    void *data;
    int off = 0;
    int len;

    if (!blobmsg_check_attr(attr, false))
        return 0;

    if (!is_array && blobmsg_name(attr)[0]) {
        lua_pushstring(L, blobmsg_name(attr));
        off++;
    }

    data = blobmsg_data(attr);
    len = blobmsg_data_len(attr);

    switch (blob_id(attr)) {
    case BLOBMSG_TYPE_BOOL:
        lua_pushboolean(L, *(uint8_t *)data);
        break;

    case BLOBMSG_TYPE_INT16:
        lua_pushinteger(L, (int16_t)be16_to_cpu(*(uint16_t *)data));
        break;

    case BLOBMSG_TYPE_INT32:
        lua_pushinteger(L, (int32_t)be32_to_cpu(*(uint32_t *)data));
        break;

    case BLOBMSG_TYPE_INT64:
        lua_pushinteger(L, (int64_t)be64_to_cpu(*(uint64_t *)data));
        break;

    case BLOBMSG_TYPE_DOUBLE: {
            union {
                double d;
                uint64_t u64;
            } v;
            v.u64 = be64_to_cpu(*(uint64_t *)data);
            lua_pushnumber(L, v.d);
        }
        break;

    case BLOBMSG_TYPE_STRING:
        lua_pushstring(L, data);
        break;

    case BLOBMSG_TYPE_ARRAY:
        blob_to_lua_table(L, data, len, true);
        break;

    case BLOBMSG_TYPE_TABLE:
        blob_to_lua_table(L, data, len, false);
        break;

    default:
        lua_pushnil(L);
        break;
    }

    return off + 1;
}

static void blob_to_lua_table(lua_State *L, struct blob_attr *attr, size_t len, bool is_array)
{
    struct blob_attr *pos;
    size_t rem = len;
    int idx = 1;
    int rv;

    lua_newtable(L);

    __blob_for_each_attr(pos, attr, rem) {
        rv = __blob_to_lua_table(L, pos, is_array);
        if (rv > 1)
            lua_rawset(L, -3);
        else if (rv > 0)
            lua_rawseti(L, -2, idx++);
    }
}

static int lua_ubus_close(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);

    if (ctx->ctx.sock.eof)
        return 0;

    ev_io_stop(ctx->eco->loop, &ctx->io);
    ev_timer_stop(ctx->eco->loop, &ctx->req.tmr);

    ubus_shutdown(&ctx->ctx);

    ctx->ctx.sock.eof = true;

    lua_rawgetp(L, LUA_REGISTRYINDEX, &obj_registry);

    lua_pushlightuserdata(L, ctx);
    lua_pushnil(L);
    lua_rawset(L, -3);

    lua_pop(L, 1);

    return 0;
}

static void ev_io_cb(struct ev_loop *loop, ev_io *w, int revents)
{
    struct eco_ubus_context *ctx = container_of(w, struct eco_ubus_context, io);

    ubus_handle_event(&ctx->ctx);
}

static void req_timeout_cb(struct ev_loop *loop, ev_timer *w, int revents)
{
    struct eco_ubus_context *ctx = container_of(w, struct eco_ubus_context, req.tmr);
    lua_State *L = ctx->req.L;

    if (!L)
        return;

    ctx->req.L = NULL;

    ubus_abort_request(&ctx->ctx, &ctx->req.req);

    lua_pushnil(L);
    lua_pushliteral(L, "timeout");
    eco_resume(ctx->eco->L, L, 2);
}

static int lua_ubus_settimeout(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    double timeout = luaL_checknumber(L, 2);

    ctx->req.timeout = timeout;
    return 0;
}

static void reconnect_cb(struct ev_loop *loop, ev_timer *w, int revents)
{
    struct eco_ubus_context *ctx = container_of(w, struct eco_ubus_context, tmr);

    if (ubus_reconnect(&ctx->ctx, ctx->path)) {
        ev_timer_set(w, 1.0, 0);
        ev_timer_start(loop, w);
        return;
    }

    ev_io_init(&ctx->io, ev_io_cb, ctx->ctx.sock.fd, EV_READ);
    ev_io_start(loop, &ctx->io);
}

static void ubus_connection_lost(struct ubus_context *ctx)
{
    struct eco_ubus_context *c = container_of(ctx, struct eco_ubus_context, ctx);
    struct ev_loop *loop = c->eco->loop;

    ev_io_stop(loop, &c->io);
    ev_timer_start(loop, &c->tmr);
}

static int lua_ubus_auto_reconnect(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);

    ctx->ctx.connection_lost = ubus_connection_lost;

    return 1;
}

static void lua_ubus_call_data_cb(struct ubus_request *req, int type, struct blob_attr *msg)
{
    struct eco_ubus_context *ctx = container_of(req, struct eco_ubus_context, req.req);

    /* I don't support multiple messages */
    if (ctx->req.has_data)
        return;

    blob_to_lua_table(ctx->req.L, blob_data(msg), blob_len(msg), false);

    ctx->req.has_data = true;
}

static void lua_ubus_call_complete_cb(struct ubus_request *req, int ret)
{
    struct eco_ubus_context *ctx = container_of(req, struct eco_ubus_context, req.req);
    lua_State *L = ctx->req.L;
    int nret = 1;

    if (!L)
        return;

    ctx->req.L = NULL;

    ev_timer_stop(ctx->eco->loop, &ctx->req.tmr);

    if (ret) {
        lua_pushnil(L);
        lua_pushstring(L, ubus_strerror(ret));
        nret++;
    } else if (!ctx->req.has_data) {
        lua_newtable(L);
    }

    eco_resume(ctx->eco->L, L, nret);
}

static int lua_ubus_call(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    const char *path = luaL_checkstring(L, 2);
    const char *func = luaL_checkstring(L, 3);
    struct blob_buf buf = {};
    uint32_t id;
    int ret;

    if (ctx->req.L) {
        lua_pushnil(L);
        lua_pushliteral(L, "busy");
        return 2;
    }

    if (ubus_lookup_id(&ctx->ctx, path, &id)) {
        lua_pushnil(L);
        lua_pushliteral(L, "not found");
        return 2;
    }

    blob_buf_init(&buf, 0);

    lua_table_to_blob(L, 4, &buf, false);

    ctx->req.has_data = false;

    ret = ubus_invoke_async(&ctx->ctx, id, func, buf.head, &ctx->req.req);
    if (ret) {
        blob_buf_free(&buf);
        lua_pushnil(L);
        lua_pushstring(L, ubus_strerror(ret));
        return 2;
    }

    ctx->req.req.data_cb = lua_ubus_call_data_cb;
    ctx->req.req.complete_cb = lua_ubus_call_complete_cb;
    ubus_complete_request_async(&ctx->ctx, &ctx->req.req);

    blob_buf_free(&buf);

    ctx->req.L = L;

    if (ctx->req.timeout > 0) {
        ev_timer_set(&ctx->req.tmr, ctx->req.timeout, 0);
        ev_timer_start(ctx->eco->loop, &ctx->req.tmr);
    }

    return lua_yield(L, 0);
}

static int lua_ubus_send(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    const char *event = luaL_checkstring(L, 2);
    struct blob_buf buf = {};

    luaL_checktype(L, 3, LUA_TTABLE);

    blob_buf_init(&buf, 0);

    lua_table_to_blob(L, 3, &buf, false);

    ubus_send_event(&ctx->ctx, event, buf.head);

    blob_buf_free(&buf);

    return 0;
}

static void lua_ubus_event_handler(struct ubus_context *ctx, struct ubus_event_handler *ev,
            const char *type, struct blob_attr *msg)
{
    struct eco_ubus_context *c = container_of(ctx, struct eco_ubus_context, ctx);
    lua_State *L = c->eco->L;

    lua_pushnil(L);

    lua_push_ubus_ctx(L, c);
    lua_getuservalue(L, -1);

    lua_pushlightuserdata(L, ev);
    lua_rawget(L, -2);

    lua_getuservalue(L, -1);

    lua_rawgeti(L, -1, 1);

    lua_replace(L, -6);

    lua_settop(L, -5);

    lua_pushstring(L, type);

    blob_to_lua_table(L, blob_data(msg), blob_len(msg), false);

    lua_call(L, 2, 0);
}

static int lua_ubus_listen(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    const char *event = luaL_checkstring(L, 2);
    struct ubus_event_handler *e;
    int ret;

    luaL_checktype(L, 3, LUA_TFUNCTION);

    e = lua_newuserdata(L, sizeof(struct ubus_event_handler));
    lua_newtable(L);
    lua_pushvalue(L, 3);
    lua_rawseti(L, -2, 1);
    lua_setuservalue(L, -2);

    memset(e, 0, sizeof(struct ubus_event_handler));

    e->cb = lua_ubus_event_handler;

    ret = ubus_register_event_handler(&ctx->ctx, e, event);
    if (ret) {
        lua_pushnil(L);
        lua_pushstring(L, ubus_strerror(ret));
        return 2;
    }

    lua_push_ubus_ctx(L, ctx);
    lua_getuservalue(L, -1);

    lua_pushlightuserdata(L, e);
    lua_pushvalue(L, -4);
    lua_rawset(L, -3);

    lua_settop(L, -3);

    return 1;
}

static int ubus_method_handler(struct ubus_context *ctx, struct ubus_object *obj,
        struct ubus_request_data *req, const char *method,
        struct blob_attr *msg)
{
    struct eco_ubus_context *c = container_of(ctx, struct eco_ubus_context, ctx);
    struct eco_ubus_object *o = container_of(obj, struct eco_ubus_object, object);
    struct ubus_request_data *dreq;
    lua_State *L = c->eco->L;
    int rv = 0;

    dreq = malloc(sizeof(struct ubus_request_data));
    if (!dreq)
        luaL_error(L, "no mem");

    lua_settop(L, 0);

    lua_pushnil(L);

    lua_push_ubus_ctx(L, c);
    lua_getuservalue(L, -1);

    lua_pushlightuserdata(L, o);
    lua_rawget(L, -2);

    lua_getuservalue(L, -1);
    lua_getfield(L, -1, method);

    lua_replace(L, -6);
    lua_settop(L, -5);

    ubus_defer_request(ctx, req, dreq);

    lua_pushlightuserdata(L, dreq);

    blob_to_lua_table(L, blob_data(msg), blob_len(msg), false);

    lua_call(L, 2, 1);

    if (lua_isnumber(L, -1))
        rv = lua_tonumber(L, -1);

    lua_pop(L, 1);

    return rv;
}

static int lua_ubus_load_methods(lua_State *L, struct ubus_method *m)
{
    const char *name = lua_tostring(L, -2);
    struct blobmsg_policy *p;
    int pidx = 0, plen;

    /* store function to uservalue */
    lua_rawgeti(L, -1, 1);
    if ((lua_type(L, -1) != LUA_TFUNCTION)) {
        lua_pop(L, 1);
        return 1;
    }
    lua_setfield(L, 5, name);

    m->handler = ubus_method_handler;
    m->name = name;

    /* get the policy table */
    lua_rawgeti(L, -1, 2);

    if ((lua_type(L, -1) != LUA_TTABLE) || lua_rawlen(L, -1)) {
        lua_pop(L, 1);
        return 0;
    }

    plen = lua_gettablelen(L, -1);

    /* exit if policy table is empty */
    if (!plen) {
        lua_pop(L, 1);
        return 0;
    }

    /* setup the policy pointers */
    p = calloc(plen, sizeof(struct blobmsg_policy));
    if (!p)
        return 1;

    m->policy = p;
    lua_pushnil(L);
    while (lua_next(L, -2) != 0) {
        int val = lua_tointeger(L, -1);

        /* check if the policy is valid */
        if ((lua_type(L, -2) != LUA_TSTRING) ||
                (lua_type(L, -1) != LUA_TNUMBER) ||
                (val < 0) ||
                (val > BLOBMSG_TYPE_LAST)) {
            lua_pop(L, 1);
            continue;
        }
        p[pidx].name = lua_tostring(L, -2);
        p[pidx].type = val;
        lua_pop(L, 1);
        pidx++;
    }

    m->n_policy = pidx;
    lua_pop(L, 1);

    return 0;
}

static void lua_ubus_load_object(lua_State *L, struct eco_ubus_object *o)
{
    struct ubus_object *obj = &o->object;
    struct ubus_object_type *type = &o->type;
    struct ubus_method *methods = o->methods;
    const char *name = lua_tostring(L, 2);
    int midx = 0;

    obj->name = name;
    obj->methods = methods;

    type->name = name;
    type->methods = methods;

    obj->type = type;

    lua_pushnil(L);
    while (lua_next(L, 3)) {
        if ((lua_type(L, -2) != LUA_TSTRING) ||
            (lua_type(L, -1) != LUA_TTABLE) ||
            !lua_rawlen(L, -1)) {
            lua_pop(L, 1);
            continue;
        }

        if (!lua_ubus_load_methods(L, methods + midx))
            midx++;
        lua_pop(L, 1);
    }

    type->n_methods = obj->n_methods = midx;
}

static int lua_ubus_add(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    struct eco_ubus_object *o;
    int ret, mlen;

    luaL_checkstring(L, 2);
    luaL_checktype(L, 3, LUA_TTABLE);

    mlen = lua_gettablelen(L, 3);

    o = lua_newuserdata(L, sizeof(struct eco_ubus_object) + mlen * sizeof(struct ubus_method));
    memset(o, 0, sizeof(struct eco_ubus_object) + mlen * sizeof(struct ubus_method));

    lua_newtable(L);

    lua_ubus_load_object(L, o);

    lua_setuservalue(L, -2);

    ret = ubus_add_object(&ctx->ctx, &o->object);
    if (ret) {
        lua_pushnil(L);
        lua_pushstring(L, ubus_strerror(ret));
        return 2;
    }

    lua_push_ubus_ctx(L, ctx);
    lua_getuservalue(L, -1);

    lua_pushlightuserdata(L, o);
    lua_pushvalue(L, -4);
    lua_rawset(L, -3);

    lua_settop(L, -3);

    return 1;
}

static int lua_ubus_reply(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    struct ubus_request_data *req = lua_touserdata(L, 2);
    struct blob_buf buf = {};

    luaL_checktype(L, 3, LUA_TTABLE);

    blob_buf_init(&buf, 0);

    lua_table_to_blob(L, 3, &buf, false);

    ubus_send_reply(&ctx->ctx, req, buf.head);

    blob_buf_free(&buf);

    return 0;
}

static int lua_ubus_complete_deferred_request(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    struct ubus_request_data *req = lua_touserdata(L, 2);
    int ret = luaL_checkinteger(L, 3);

    ubus_complete_deferred_request(&ctx->ctx, req, ret);
    free(req);

    return 0;
}

static int lua_ubus_connect(lua_State *L)
{
    const char *path = luaL_optstring(L, 1, NULL);
    size_t size = sizeof(struct eco_ubus_context);
    struct eco_ubus_context *ctx;

    if (getuid() > 0) {
        lua_pushnil(L);
        lua_pushliteral(L, "Operation not permitted, must be run as root");
        return 2;
    }

    if (path)
        size += strlen(path) + 1;

    ctx = lua_newuserdata(L, size);
    memset(ctx, 0, sizeof(struct eco_ubus_context));

    if (ubus_connect_ctx(&ctx->ctx, path)) {
        uloop_done();
        lua_pushnil(L);
        lua_pushliteral(L, "Failed to connect to ubus");
        return 2;
    }

    uloop_done();

    if (path) {
        strcpy(ctx->path_data, path);
        ctx->path = ctx->path_data;
    }

    lua_pushvalue(L, lua_upvalueindex(1));
    lua_setmetatable(L, -2);

    lua_newtable(L);
    lua_setuservalue(L, -2);

    lua_rawgetp(L, LUA_REGISTRYINDEX, &obj_registry);
    lua_pushlightuserdata(L, ctx);
    lua_pushvalue(L, -3);
    lua_rawset(L, -3);
    lua_pop(L, 1);

    ctx->eco = eco_get_context(L);

    ev_io_init(&ctx->io, ev_io_cb, ctx->ctx.sock.fd, EV_READ);
    ev_io_start(ctx->eco->loop, &ctx->io);

    ev_timer_init(&ctx->tmr, reconnect_cb, 1.0, 0);
    ev_timer_init(&ctx->req.tmr, req_timeout_cb, 30.0, 0);

    return 1;
}

static void lua_ubus_objects_cb(struct ubus_context *c, struct ubus_object_data *o, void *p)
{
    lua_State *L = (lua_State *)p;

    lua_pushstring(L, o->path);
    lua_rawseti(L, -2, lua_rawlen(L, -2) + 1);
}

static int lua_ubus_handle_objects(lua_State *L)
{
    struct eco_ubus_context *ctx = luaL_checkudata(L, 1, ECO_UBUS_CTX_MT);
    int ret;

    lua_newtable(L);

    ret = ubus_lookup(&ctx->ctx, NULL, lua_ubus_objects_cb, L);
    if (ret != UBUS_STATUS_OK) {
        lua_pop(L, 1);
        lua_pushnil(L);
        lua_pushstring(L, ubus_strerror(ret));
        return 2;
    }

    return 1;
}

static const struct luaL_Reg ubus_methods[] =  {
    {"settimeout", lua_ubus_settimeout},
    {"auto_reconnect", lua_ubus_auto_reconnect},
    {"call", lua_ubus_call},
    {"send", lua_ubus_send},
    {"listen", lua_ubus_listen},
    {"add", lua_ubus_add},
    {"reply", lua_ubus_reply},
    {"complete_deferred_request", lua_ubus_complete_deferred_request},
    {"objects", lua_ubus_handle_objects},
    {"close", lua_ubus_close},
    {"__gc", lua_ubus_close},
    {NULL, NULL}
};

static int lua_ubus_strerror(lua_State *L)
{
    int ret = luaL_checkinteger(L, 1);

    lua_pushstring(L, ubus_strerror(ret));

    return 1;
}

int luaopen_eco_core_ubus(lua_State *L)
{
    lua_newtable(L);
    lua_createtable(L, 0, 1);
    lua_pushliteral(L, "v");
    lua_setfield(L, -2, "__mode");
    lua_setmetatable(L, -2);
    lua_rawsetp(L, LUA_REGISTRYINDEX, &obj_registry);

    lua_newtable(L);

    lua_add_constant(L, "STATUS_OK", UBUS_STATUS_OK);
    lua_add_constant(L, "STATUS_INVALID_COMMAND", UBUS_STATUS_INVALID_COMMAND);
    lua_add_constant(L, "STATUS_INVALID_ARGUMENT", UBUS_STATUS_INVALID_ARGUMENT);
    lua_add_constant(L, "STATUS_METHOD_NOT_FOUND", UBUS_STATUS_METHOD_NOT_FOUND);
    lua_add_constant(L, "STATUS_NOT_FOUND", UBUS_STATUS_NOT_FOUND);
    lua_add_constant(L, "STATUS_NO_DATA", UBUS_STATUS_NO_DATA);
    lua_add_constant(L, "STATUS_PERMISSION_DENIED", UBUS_STATUS_PERMISSION_DENIED);
    lua_add_constant(L, "STATUS_TIMEOUT", UBUS_STATUS_TIMEOUT);
    lua_add_constant(L, "STATUS_NOT_SUPPORTED", UBUS_STATUS_NOT_SUPPORTED);
    lua_add_constant(L, "STATUS_UNKNOWN_ERROR", UBUS_STATUS_UNKNOWN_ERROR);
    lua_add_constant(L, "STATUS_CONNECTION_FAILED", UBUS_STATUS_CONNECTION_FAILED);

    lua_add_constant(L, "ARRAY", BLOBMSG_TYPE_ARRAY);
    lua_add_constant(L, "TABLE", BLOBMSG_TYPE_TABLE);
    lua_add_constant(L, "STRING", BLOBMSG_TYPE_STRING);
    lua_add_constant(L, "INT64", BLOBMSG_TYPE_INT64);
    lua_add_constant(L, "INT32", BLOBMSG_TYPE_INT32);
    lua_add_constant(L, "INT16", BLOBMSG_TYPE_INT16);
    lua_add_constant(L, "INT8", BLOBMSG_TYPE_INT8);
    lua_add_constant(L, "DOUBLE", BLOBMSG_TYPE_DOUBLE);
    lua_add_constant(L, "BOOLEAN", BLOBMSG_TYPE_BOOL);

    eco_new_metatable(L, ECO_UBUS_CTX_MT, ubus_methods);
    lua_pushcclosure(L, lua_ubus_connect, 1);
    lua_setfield(L, -2, "connect");

    lua_pushcfunction(L, lua_ubus_strerror);
    lua_setfield(L, -2, "strerror");

    return 1;
}