/*
    Authors:
        Pavel Březina <pbrezina@redhat.com>

    Copyright (C) 2011 Red Hat

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    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.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <errno.h>
#include <string.h>
#include <tevent.h>

#include "providers/dp_backend.h"
#include "providers/ldap/ldap_common.h"
#include "providers/ldap/sdap.h"
#include "providers/ldap/sdap_async.h"
#include "providers/ldap/sdap_sudo.h"
#include "providers/ldap/sdap_sudo_cache.h"
#include "providers/ldap/sdap_sudo_timer.h"
#include "db/sysdb_sudo.h"

static void
sdap_sudo_shutdown(struct be_req *req)
{
    sdap_handler_done(req, DP_ERR_OK, EOK, NULL);
}

struct bet_ops sdap_sudo_ops = {
    .handler = sdap_sudo_handler,
    .finalize = sdap_sudo_shutdown
};

int sdap_sudo_setup_tasks(struct sdap_id_ctx *id_ctx);

int sdap_sudo_init(struct be_ctx *be_ctx,
                   struct sdap_id_ctx *id_ctx,
                   struct bet_ops **ops,
                   void **pvt_data)
{
    int ret;

    DEBUG(SSSDBG_TRACE_INTERNAL, ("Initializing sudo LDAP back end\n"));

    *ops = &sdap_sudo_ops;
    *pvt_data = id_ctx;

    ret = ldap_get_sudo_options(id_ctx, be_ctx->cdb,
                                be_ctx->conf_path, id_ctx->opts);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("Cannot get SUDO options [%d]: %s\n",
                                  ret, strerror(ret)));
        return ret;
    }

    ret = sdap_sudo_setup_tasks(id_ctx);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("SUDO setup failed [%d]: %s\n",
                                  ret, strerror(ret)));
        return ret;
    }

    return EOK;
}

int sdap_sudo_setup_tasks(struct sdap_id_ctx *id_ctx)
{
    struct sdap_sudo_refresh_ctx *refresh_ctx = NULL;
    struct timeval tv;
    int ret = EOK;
    bool refreshed = false;
    bool refresh_enabled = dp_opt_get_bool(id_ctx->opts->basic,
                                           SDAP_SUDO_REFRESH_ENABLED);

    /* set up periodical update of sudo rules */
    if (refresh_enabled) {
        refresh_ctx = sdap_sudo_refresh_ctx_init(id_ctx, id_ctx->be, id_ctx,
                                                 id_ctx->opts,
                                                 tevent_timeval_zero());
        if (refresh_ctx == NULL) {
            DEBUG(SSSDBG_CRIT_FAILURE,
                  ("sdap_sudo_refresh_ctx_init() failed!\n"));
            return ENOMEM;
        }

        /* If this is the first startup, we need to kick off
         * an refresh immediately, to close a window where
         * clients requesting sudo information won't get an
         * immediate reply with no entries
         */
        ret = sysdb_sudo_get_refreshed(id_ctx->be->sysdb, &refreshed);
        if (ret != EOK) {
            return ret;
        }
        if (refreshed) {
            /* At least one update has previously run,
             * so clients will get cached data. We will delay
             * starting to enumerate by 10s so we don't slow
             * down the startup process if this is happening
             * during system boot.
             */
            tv = tevent_timeval_current_ofs(10, 0);
            DEBUG(SSSDBG_FUNC_DATA, ("Delaying first refresh of SUDO rules "
                  "for 10 seconds\n"));
        } else {
            /* This is our first startup. Schedule the
             * update to start immediately once we
             * enter the mainloop.
             */
            tv = tevent_timeval_current();
        }

        ret = sdap_sudo_refresh_set_timer(refresh_ctx, tv);
        if (ret != EOK) {
            talloc_free(refresh_ctx);
            return ret;
        }
    }

    return EOK;
}

static void sdap_sudo_reply(struct tevent_req *req)
{
    struct be_req *be_req = NULL;
    int dp_error;
    int error;
    int ret;

    be_req = tevent_req_callback_data(req, struct be_req);
    ret = sdap_sudo_refresh_recv(req, &dp_error, &error);
    talloc_zfree(req);
    if (ret != EOK) {
        sdap_handler_done(be_req, DP_ERR_FATAL, ret, strerror(ret));
        return;
    }

    sdap_handler_done(be_req, dp_error, error, strerror(error));
}

void sdap_sudo_handler(struct be_req *be_req)
{
    struct tevent_req *req = NULL;
    struct be_sudo_req *sudo_req = NULL;
    struct sdap_id_ctx *id_ctx = NULL;
    int ret = EOK;

    id_ctx = talloc_get_type(be_req->be_ctx->bet_info[BET_SUDO].pvt_bet_data,
                             struct sdap_id_ctx);

    sudo_req = talloc_get_type(be_req->req_data, struct be_sudo_req);

    /* get user info */
    if (sudo_req->username != NULL) {
        ret = sysdb_get_sudo_user_info(sudo_req, sudo_req->username,
                                       id_ctx->be->sysdb,
                                       &sudo_req->uid, &sudo_req->groups);
        if (ret != EOK) {
            DEBUG(SSSDBG_CRIT_FAILURE, ("Unable to get uid and groups of %s\n",
                  sudo_req->username));
            goto fail;
        }
    } else {
        sudo_req->uid = 0;
        sudo_req->groups = NULL;
    }

    req = sdap_sudo_refresh_send(be_req, id_ctx->be, id_ctx->opts,
                                 id_ctx->conn_cache, NULL, NULL);
    if (req == NULL) {
        ret = ENOMEM;
        goto fail;
    }

    tevent_req_set_callback(req, sdap_sudo_reply, be_req);

    return;

fail:
    sdap_handler_done(be_req, DP_ERR_FATAL, ret, NULL);
}