/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 * 

 */

#include <stdint.h>

#include <ap_config.h>

#include "ap_mpm.h"

#include <http_core.h>

#include <httpd.h>

#include <http_log.h>

#include <apr_version.h>

#include <apr_pools.h>

#include <apr_strings.h>

#include "unixd.h"

#include "scoreboard.h"

#include "mpm_common.h"

#include "systemd/sd-daemon.h"

#include "systemd/sd-journal.h"

#if APR_HAVE_UNISTD_H

#include <unistd.h>

#endif

static int shutdown_timer = 0;

static int shutdown_counter = 0;

static unsigned long bytes_served;

static pid_t mainpid;

static char describe_listeners[50];

static int systemd_pre_config(apr_pool_t *pconf, apr_pool_t *plog,

                              apr_pool_t *ptemp)

{

    sd_notify(0,

              "RELOADING=1\n"

              "STATUS=Reading configuration...\n");

    ap_extended_status = 1;

    return OK;

}

static char *dump_listener(ap_listen_rec *lr, apr_pool_t *p)

{

    apr_sockaddr_t *sa = lr->bind_addr;

    char addr[128];

    if (apr_sockaddr_is_wildcard(sa)) {

        return apr_pstrcat(p, "port ", apr_itoa(p, sa->port), NULL);

    }

    apr_sockaddr_ip_getbuf(addr, sizeof addr, sa);

    return apr_psprintf(p, "%s port %u", addr, sa->port);

}

static int systemd_post_config(apr_pool_t *pconf, apr_pool_t *plog,

                               apr_pool_t *ptemp, server_rec *s)

{

    ap_listen_rec *lr;

    apr_size_t plen = sizeof describe_listeners;

    char *p = describe_listeners;

    if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG)

        return OK;

    for (lr = ap_listeners; lr; lr = lr->next) {

        char *s = dump_listener(lr, ptemp);

        if (strlen(s) + 3 < plen) {

            char *newp = apr_cpystrn(p, s, plen);

            if (lr->next)

                newp = apr_cpystrn(newp, ", ", 3);

            plen -= newp - p;

            p = newp;

        }

        else {

            if (plen < 4) {

                p = describe_listeners + sizeof describe_listeners - 4;

                plen = 4;

            }

            apr_cpystrn(p, "...", plen);

            break;

        }

    }

    sd_journal_print(LOG_INFO, "Server configured, listening on: %s", describe_listeners);

    return OK;

}

/* Report the service is ready in post_config, which could be during

 * startup or after a reload.  The server could still hit a fatal

 * startup error after this point during ap_run_mpm(), so this is

 * perhaps too early, but by post_config listen() has been called on

 * the TCP ports so new connections will not be rejected.  There will

 * always be a possible async failure event simultaneous to the

 * service reporting "ready", so this should be good enough. */

static int systemd_post_config_last(apr_pool_t *p, apr_pool_t *plog,

                               apr_pool_t *ptemp, server_rec *main_server)

{

    sd_notify(0, "READY=1\n"

              "STATUS=Configuration loaded.\n");

    return OK;

}

static int systemd_pre_mpm(apr_pool_t *p, ap_scoreboard_e sb_type)

{

    int rv;

    mainpid = getpid();

    rv = sd_notifyf(0, "READY=1\n"

                    "STATUS=Started, listening on: %s\n"

                    "MAINPID=%" APR_PID_T_FMT,

                    describe_listeners, mainpid);

    if (rv < 0) {

        ap_log_perror(APLOG_MARK, APLOG_ERR, 0, p, APLOGNO(02395)

                     "sd_notifyf returned an error %d", rv);

    }

    return OK;

}

static int systemd_monitor(apr_pool_t *p, server_rec *s)

{

    ap_sload_t sload;

    apr_interval_time_t up_time;

    char bps[5];

    int rv;

    if (!ap_extended_status) {

        /* Nothing useful to report if ExtendedStatus disabled. */

        return DECLINED;

    }

    ap_get_sload(&sload);

    if (sload.access_count == 0) {

        rv = sd_notifyf(0, "READY=1\n"

                        "STATUS=Running, listening on: %s\n",

                        describe_listeners);

    }

    else {

        /* up_time in seconds */

        up_time = (apr_uint32_t) apr_time_sec(apr_time_now() -

                                              ap_scoreboard_image->global->restart_time);

        apr_strfsize((unsigned long)((float) (sload.bytes_served)

                                     / (float) up_time), bps);

        rv = sd_notifyf(0, "READY=1\n"

                        "STATUS=Total requests: %lu; Idle/Busy workers %d/%d;"

                        "Requests/sec: %.3g; Bytes served/sec: %sB/sec\n",

                        sload.access_count, sload.idle, sload.busy,

                        ((float) sload.access_count) / (float) up_time, bps);

    }

    if (rv < 0) {

        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(02396)

                     "sd_notifyf returned an error %d", rv);

    }

    /* Shutdown httpd when nothing is sent for shutdown_timer seconds. */

    if (sload.bytes_served == bytes_served) {

        /* mpm_common.c: INTERVAL_OF_WRITABLE_PROBES is 10 */

        shutdown_counter += 10;

        if (shutdown_timer > 0 && shutdown_counter >= shutdown_timer) {

            rv = sd_notifyf(0, "READY=1\n"

                            "STATUS=Stopped as result of IdleShutdown "

                            "timeout.");

            if (rv < 0) {

                ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(02804)

                            "sd_notifyf returned an error %d", rv);

            }

            kill(mainpid, AP_SIG_GRACEFUL);

        }

    }

    else {

        shutdown_counter = 0;

    }

    bytes_served = sload.bytes_served;

    return DECLINED;

}

static void systemd_register_hooks(apr_pool_t *p)

{

    /* Enable ap_extended_status. */

    ap_hook_pre_config(systemd_pre_config, NULL, NULL, APR_HOOK_LAST);

    /* Grab the listener config. */

    ap_hook_post_config(systemd_post_config, NULL, NULL, APR_HOOK_LAST);

    /* Signal service is ready. */

    ap_hook_post_config(systemd_post_config_last, NULL, NULL, APR_HOOK_REALLY_LAST);

    /* We know the PID in this hook ... */

    ap_hook_pre_mpm(systemd_pre_mpm, NULL, NULL, APR_HOOK_LAST);

    /* Used to update httpd's status line using sd_notifyf */

    ap_hook_monitor(systemd_monitor, NULL, NULL, APR_HOOK_MIDDLE);

}

static const char *set_shutdown_timer(cmd_parms *cmd, void *dummy,

                                      const char *arg)

{

    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);

    if (err != NULL) {

        return err;

    }

    shutdown_timer = atoi(arg);

    return NULL;

}

static const command_rec systemd_cmds[] =

{

AP_INIT_TAKE1("IdleShutdown", set_shutdown_timer, NULL, RSRC_CONF,

     "Number of seconds in idle-state after which httpd is shutdown"),

    {NULL}

};

AP_DECLARE_MODULE(systemd) = {

    STANDARD20_MODULE_STUFF,

    NULL,

    NULL,

    NULL,

    NULL,

    systemd_cmds,

    systemd_register_hooks,

};