[paraslash.git] / audiod.c

/*
 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
 *
 * Licensed under the GPL v2. For licencing details see COPYING.
 */

/** \file audiod.c the paraslash's audio daemon */
#include <sys/types.h>
#include <dirent.h>
#include <signal.h>

#include "para.h"
#include "error.h"
#include "audiod.cmdline.h"
#include "list.h"
#include "sched.h"
#include "recv.h"
#include "ggo.h"
#include "filter.h"
#include "grab_client.cmdline.h"
#include "grab_client.h"
#include "client.cmdline.h"
#include "client.h"
#include "audiod.h"
#include "net.h"
#include "daemon.h"
#include "string.h"
#include "fd.h"
#include "write.h"
#include "write_common.h"
#include "signal.h"

/** define the array of error lists needed by para_audiod */
INIT_AUDIOD_ERRLISTS;
/** define the array containing all supported audio formats */
const char *audio_formats[] = {AUDIOD_AUDIO_FORMAT_ARRAY NULL};

/** Defines how audiod handles one supported audio format. */
struct audio_format_info {
        /** pointer to the receiver for this audio format */
        struct receiver *receiver;
        /** the receiver configuration */
        void *receiver_conf;
        /** the number of filters that should be activated for this audio format */
        unsigned int num_filters;
        /** Array of filter numbers to be activated. */
        unsigned *filter_nums;
        /** Pointer to the array of filter configurations. */
        void **filter_conf;
        /** the number of filters that should be activated for this audio format */
        unsigned int num_writers;
        /** pointer to the array of writers to be activated */
        struct writer **writers;
        /** pointer to the array of writer configurations */
        void **writer_conf;
        /** do not start receiver/filters/writer before this time */
        struct timeval restart_barrier;
};

/**
 * para_audiod uses \p MAX_STREAM_SLOTS different slots, each of which may
 * be associated with a receiver/filter/writer triple. This array holds all
 * information on the status of these slots.
 *
 * \sa struct slot_info
 * */
struct slot_info slot[MAX_STREAM_SLOTS];


/** The array of status items sent by para_server. */
char *stat_item_values[NUM_STAT_ITEMS] = {NULL};

/**
 * the current mode of operation of which can be changed by the on/off/cycle
 * commands. It is either, AUDIOD_OFF, AUDIOD_ON or AUDIOD_STANDBY.
 */
int audiod_status = AUDIOD_ON;

/**
 * the gengetopt args_info struct that holds information on all command line
 * arguments
 */
struct audiod_args_info conf;

static char *socket_name;
static FILE *logfile;
static struct audio_format_info afi[NUM_AUDIO_FORMATS];

static struct signal_task signal_task_struct, *sig_task = &signal_task_struct;

static struct status_task status_task_struct;

/**
 * the task that calls the status command of para_server
 *
 * \sa struct status_task
 */
static struct status_task *stat_task = &status_task_struct;
static struct timeval initial_delay_barrier;

/**
 * the task for handling audiod commands
 *
 * \sa struct task, struct sched
 */
struct command_task {
        /** the local listening socket */
        int fd;
        /** the associated task structure */
        struct task task;
};

/** iterate over all supported audio formats */
#define FOR_EACH_AUDIO_FORMAT(af) for (af = 0; af < NUM_AUDIO_FORMATS; af++)

/**
 * get the audio format number
 * \param name the name of the audio format
 *
 * \return The audio format number on success, -E_UNSUPPORTED_AUDIO_FORMAT if
 * \a name is not a supported audio format.
 */
int get_audio_format_num(char *name)
{
        int i;

        while (para_isspace(*name))
                name++;
        FOR_EACH_AUDIO_FORMAT(i)
                if (!strcmp(name, audio_formats[i]))
                        return i;
        return -E_UNSUPPORTED_AUDIO_FORMAT;
}

char *get_time_string(struct timeval *newest_stime)
{
        struct timeval diff, adj_stream_start, tmp;
        int total = 0, use_server_time = 1,
                length_seconds = stat_task->length_seconds;

        if (!stat_task->playing) {
                if (length_seconds)
                        return NULL;
                return make_message("%s:\n", status_item_list[SI_PLAY_TIME]);
        }
        if (audiod_status == AUDIOD_OFF)
                goto out;
        if (stat_task->sa_time_diff_sign > 0)
                tv_diff(&stat_task->server_stream_start, &stat_task->sa_time_diff,
                        &adj_stream_start);
        else
                tv_add(&stat_task->server_stream_start, &stat_task->sa_time_diff,
                        &adj_stream_start);
        tmp = adj_stream_start;
        if (newest_stime && audiod_status == AUDIOD_ON) {
                tv_diff(newest_stime, &adj_stream_start, &diff);
                if (tv2ms(&diff) < 5000) {
                        tmp = *newest_stime;
                        use_server_time = 0;
                }
        }
        tv_diff(now, &tmp, &diff);
        total = diff.tv_sec + stat_task->offset_seconds;
        if (total > length_seconds)
                total = length_seconds;
        if (total < 0)
                total = 0;
out:
        return make_message(
                "%s: %s%d:%02d [%d:%02d] (%d%%/%d:%02d)\n",
                status_item_list[SI_PLAY_TIME],
                use_server_time? "~" : "",
                total / 60,
                total % 60,
                (length_seconds - total) / 60,
                (length_seconds - total) % 60,
                length_seconds? (total * 100 + length_seconds / 2) /
                        length_seconds : 0,
                length_seconds / 60,
                length_seconds % 60
        );
}

/**
 * the log function of para_audiod
 *
 * \param ll loglevel
 * \param fmt the format string
 */
__printf_2_3 void para_log(int ll, const char* fmt,...)
{
        va_list argp;
        FILE *outfd;
        struct tm *tm;
        time_t t1;
        char str[MAXLINE] = "";
        static char *hostname;

        if (ll < conf.loglevel_arg)
                return;
        if (!logfile && conf.daemon_given)
                return;
        if (!hostname)
                hostname = para_hostname();
        outfd = logfile? logfile : stderr;
        time(&t1);
        tm = localtime(&t1);
        strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
        fprintf(outfd, "%s %s ", str, hostname);
        if (conf.loglevel_arg <= INFO)
                fprintf(outfd, "%i ", ll);
        va_start(argp, fmt);
        vfprintf(outfd, fmt, argp);
        va_end(argp);
}

static char *configfile_exists(void)
{
        char *home = para_homedir();
        char *config_file = make_message("%s/.paraslash/audiod.conf",
                home);
        free(home);
        if (file_exists(config_file))
                return config_file;
        free(config_file);
        return NULL;
}

static void setup_signal_handling(void)
{
        sig_task->fd = para_signal_init();
        PARA_INFO_LOG("signal pipe: fd %d\n", sig_task->fd);
        para_install_sighandler(SIGINT);
        para_install_sighandler(SIGTERM);
        para_install_sighandler(SIGHUP);
        signal(SIGPIPE, SIG_IGN);
}

static void clear_slot(int slot_num)
{
        struct slot_info *s = &slot[slot_num];

        PARA_INFO_LOG("clearing slot %d\n", slot_num);
        memset(s, 0, sizeof(struct slot_info));
        s->format = -1;
}

static void close_receiver(int slot_num)
{
        struct slot_info *s = &slot[slot_num];
        struct audio_format_info *a;

        if (s->format < 0 || !s->receiver_node)
                return;
        a = &afi[s->format];
        PARA_NOTICE_LOG("closing %s receiver in slot %d\n",
                audio_formats[s->format], slot_num);
        a->receiver->close(s->receiver_node);
        free(s->receiver_node);
        s->receiver_node = NULL;
}

static void kill_all_decoders(int error)
{
        int i;

        FOR_EACH_SLOT(i) {
                struct slot_info *s = &slot[i];
                if (s->wng && s->wng->task.error >= 0) {
                        PARA_INFO_LOG("deactivating wng in slot %d\n",
                                i);
                        s->wng->task.error = error;
                }
                if (s->fc && s->fc->task.error >= 0) {
                        PARA_INFO_LOG("deactivatimg filter chain in slot %d\n", i);
                        s->fc->task.error = error;
                }
                if (s->receiver_node && s->receiver_node->task.error >= 0) {
                        PARA_INFO_LOG("deactivating receiver_node in slot %d\n", i);
                        s->receiver_node->task.error = error;
                }
        }
}

static int get_empty_slot(void)
{
        int i;
        struct slot_info *s;

        FOR_EACH_SLOT(i) {
                s = &slot[i];
                if (s->format < 0) {
                        clear_slot(i);
                        return i;
                }
                if (s->wng || s->receiver_node || s->fc)
                        continue;
                clear_slot(i);
                return i;
        }
        return -E_NO_MORE_SLOTS;
}

/**
 * get the number of filters
 *
 * \param audio_format_num the number identifying the audio format
 *
 * \return the number of filters for the given audio format
 *
 * \sa struct filter;
 */
int num_filters(int audio_format_num)
{
        return afi[audio_format_num].num_filters;
}

static void open_filters(int slot_num)
{
        struct slot_info *s = &slot[slot_num];
        struct audio_format_info *a = &afi[s->format];
        struct filter_node *fn;
        int nf = a->num_filters;
        int i;

        s->fc = NULL;
        if (!nf)
                return;
        PARA_INFO_LOG("opening %s filters\n", audio_formats[s->format]);
        s->fc = para_calloc(sizeof(struct filter_chain));
        s->fc->filter_nodes = para_malloc(nf * sizeof(struct filter_node));
        s->fc->inbuf = s->receiver_node->buf;
        s->fc->in_loaded = &s->receiver_node->loaded;
        s->fc->input_error = &s->receiver_node->task.error;
        s->fc->task.pre_select = filter_pre_select;
        s->fc->task.post_select = NULL;
        s->fc->task.error = 0;
        s->fc->num_filters = nf;

        s->receiver_node->output_error = &s->fc->task.error;
        sprintf(s->fc->task.status, "filter chain");
        FOR_EACH_FILTER_NODE(fn, s->fc, i) {
                struct filter *f = filters + a->filter_nums[i];
                fn->filter_num = a->filter_nums[i];
                fn->conf = a->filter_conf[i];
                fn->fc = s->fc;
                fn->loaded = 0;
                INIT_LIST_HEAD(&fn->callbacks);
                f->open(fn);
                PARA_NOTICE_LOG("%s filter %d/%d (%s) started in slot %d\n",
                        audio_formats[s->format], i,  nf, f->name, slot_num);
                s->fc->outbuf = fn->buf;
                s->fc->out_loaded = &fn->loaded;
        }
        register_task(&s->fc->task);
}

static void open_writers(int slot_num)
{
        int ret, i;
        struct slot_info *s = &slot[slot_num];
        struct audio_format_info *a = &afi[s->format];

        PARA_INFO_LOG("opening %s writers\n", audio_formats[s->format]);
        if (!a->num_writers)
                s->wng = setup_default_wng();
        else
                s->wng = wng_new(a->num_writers);
        if (s->fc) {
                s->wng->buf = s->fc->outbuf;
                s->wng->loaded = s->fc->out_loaded;
                s->wng->input_error = &s->fc->task.error;
                s->wng->channels = &s->fc->channels;
                s->wng->samplerate = &s->fc->samplerate;
                s->fc->output_error = &s->wng->task.error;
                PARA_INFO_LOG("samplerate: %d\n", *s->wng->samplerate);
        } else {
                s->wng->buf = s->receiver_node->buf;
                s->wng->loaded = &s->receiver_node->loaded;
                s->wng->input_error = &s->receiver_node->task.error;
        }
        for (i = 0; i < a->num_writers; i++) {
                s->wng->writer_nodes[i].conf = a->writer_conf[i];
                s->wng->writer_nodes[i].writer = a->writers[i];
        }
        ret = wng_open(s->wng);
        if (ret < 0) {
                PARA_ERROR_LOG("%s\n", para_strerror(-ret));
                return;
        }
        s->wstime = *now;
        activate_inactive_grab_clients(slot_num, s->format, s->fc);
}

static int open_receiver(int format)
{
        struct audio_format_info *a = &afi[format];
        struct slot_info *s;
        int ret, slot_num;
        struct receiver_node *rn;
        const struct timeval restart_delay = {2, 0};

        ret = get_empty_slot();
        if (ret < 0)
                goto err;
        slot_num = ret;
        s = &slot[slot_num];
        s->format = format;
        s->receiver_node = para_calloc(sizeof(struct receiver_node));
        rn = s->receiver_node;
        rn->receiver = a->receiver;
        rn->conf = a->receiver_conf;
        ret = a->receiver->open(s->receiver_node);
        if (ret < 0) {
                free(s->receiver_node);
                s->receiver_node = NULL;
                goto err;
        }
        PARA_NOTICE_LOG("started %s: %s receiver in slot %d\n",
                audio_formats[s->format], a->receiver->name, slot_num);
        rn->task.pre_select = a->receiver->pre_select;
        rn->task.post_select = a->receiver->post_select;
        sprintf(rn->task.status, "%s receiver node", rn->receiver->name);
        register_task(&rn->task);
        ret = 1;
err:
        if (ret < 0)
                PARA_ERROR_LOG("%s\n", para_strerror(-ret));
        tv_add(now, &restart_delay, &afi[format].restart_barrier);
        return ret;
}

static int receiver_running(int format)
{
        int i;

        FOR_EACH_SLOT(i) {
                struct slot_info *s = &slot[i];
                if (s->format == format && s->receiver_node)
                        return 1;
        }
        return 0;
}

static int open_current_receiver(struct sched *s)
{
        struct timeval diff;
        int cafn = stat_task->current_audio_format_num;

        if (cafn < 0 || !stat_task->ct)
                return 0;
        if (receiver_running(cafn))
                return 0;
        if (tv_diff(now, &afi[cafn].restart_barrier, &diff) < 0) {
                s->timeout = diff;
                return 0;
        }
        return open_receiver(cafn) < 0? 0 : 1;
}

static unsigned compute_time_diff(const struct timeval *status_time)
{
        struct timeval tmp, diff;
        static unsigned count;
        int sign, sa_time_diff_sign = stat_task->sa_time_diff_sign;
        const struct timeval max_deviation = {0, 500 * 1000};
        const int time_smooth = 5;

        if (!status_time)
                return count;
        sign = tv_diff(status_time, now, &diff);
//              PARA_NOTICE_LOG("%s: sign = %i, sa_time_diff_sign = %i\n", __func__,
//                      sign, sa_time_diff_sign);
        if (!count) {
                sa_time_diff_sign = sign;
                stat_task->sa_time_diff = diff;
                count++;
                goto out;
        }
        if (count > 5) {
                int s = tv_diff(&diff, &stat_task->sa_time_diff, &tmp);
                if (tv_diff(&max_deviation, &tmp, NULL) < 0)
                        PARA_WARNING_LOG("time diff jump: %lims\n",
                                s * tv2ms(&tmp));
        }
        count++;
        sa_time_diff_sign = tv_convex_combination(
                sa_time_diff_sign * time_smooth, &stat_task->sa_time_diff,
                count > 10? sign : sign * time_smooth, &diff,
                &tmp);
        stat_task->sa_time_diff = tmp;
        PARA_INFO_LOG("time diff (cur/avg): %s%lums/%s%lums\n",
                sign > 0? "+" : "-",
                tv2ms(&diff),
                sa_time_diff_sign ? "+" : "-",
                tv2ms(&stat_task->sa_time_diff)
        );
out:
        stat_task->sa_time_diff_sign = sa_time_diff_sign;
        return count;
}

static int check_stat_line(char *line, __a_unused void *data)
{
        int itemnum;
        size_t ilen = 0;
        long unsigned sec, usec;
        char *tmp;

        //PARA_INFO_LOG("line: %s\n", line);
        if (!line)
                return 1;
        itemnum = stat_line_valid(line);
        if (itemnum < 0) {
                PARA_WARNING_LOG("invalid status line: %s\n", line);
                return 1;
        }
        if (stat_task->clock_diff_count && itemnum != SI_CURRENT_TIME)
                return 1;
        tmp = make_message("%s\n", line);
        stat_client_write(tmp, itemnum);
        free(tmp);
        free(stat_item_values[itemnum]);
        stat_item_values[itemnum] = para_strdup(line);
        ilen = strlen(status_item_list[itemnum]);
        switch (itemnum) {
        case SI_STATUS:
                stat_task->playing = strstr(line, "playing")? 1 : 0;
                PARA_INFO_LOG("stat task playing: %d\n", stat_task->playing);
                break;
        case SI_OFFSET:
                stat_task->offset_seconds = atoi(line + ilen + 1);
                break;
        case SI_SECONDS_TOTAL:
                stat_task->length_seconds = atoi(line + ilen + 1);
                break;
        case SI_STREAM_START:
                if (sscanf(line + ilen + 1, "%lu.%lu", &sec, &usec) == 2) {
                        struct timeval a_start, delay;
                        delay.tv_sec = conf.stream_delay_arg / 1000;
                        delay.tv_usec = (conf.stream_delay_arg % 1000) * 1000;
                        stat_task->server_stream_start.tv_sec = sec;
                        stat_task->server_stream_start.tv_usec = usec;
                        if (compute_time_diff(NULL) > 2) {
                                if (stat_task->sa_time_diff_sign < 0)
                                        tv_add(&stat_task->server_stream_start,
                                                &stat_task->sa_time_diff, &a_start);
                                else
                                        tv_diff(&stat_task->server_stream_start,
                                                &stat_task->sa_time_diff, &a_start);
                                tv_add(&a_start, &delay, &initial_delay_barrier);
                        }
                }
                break;
        case SI_CURRENT_TIME:
                if (sscanf(line + ilen + 1, "%lu.%lu", &sec, &usec) == 2) {
                        struct timeval tv = {sec, usec};
                        compute_time_diff(&tv);
                }
                break;
        case SI_FORMAT:
                stat_task->current_audio_format_num = get_audio_format_num(
                        line + ilen + 1);
        }
        return 1;
}

static int parse_stream_command(const char *txt, char **cmd)
{
        char *p = strchr(txt, ':');
        int i;

        if (!p)
                return -E_MISSING_COLON;
        p++;
        FOR_EACH_AUDIO_FORMAT(i) {
                if (strncmp(txt, audio_formats[i], strlen(audio_formats[i])))
                        continue;
                *cmd = p;
                return i;
        }
        return -E_UNSUPPORTED_AUDIO_FORMAT;
}

static int add_filter(int format, char *cmdline)
{
        struct audio_format_info *a = &afi[format];
        int filter_num, nf = a->num_filters;

        filter_num = check_filter_arg(cmdline, &a->filter_conf[nf]);
        if (filter_num < 0)
                return filter_num;
        a->filter_nums[nf] = filter_num;
        a->num_filters++;
        PARA_INFO_LOG("%s filter %d: %s\n", audio_formats[format], nf,
                filters[filter_num].name);
        return filter_num;
}

static int init_writers(void)
{
        int i, ret, nw;
        char *cmd;
        struct audio_format_info *a;

        init_supported_writers();
        nw = PARA_MAX(1U, conf.writer_given);
        PARA_INFO_LOG("maximal number of writers: %d\n", nw);
        FOR_EACH_AUDIO_FORMAT(i) {
                a = &afi[i];
                a->writer_conf = para_malloc(nw * sizeof(void *));
                a->writers = para_malloc(nw * sizeof(struct writer *));
                a->num_writers = 0;
        }
        for (i = 0; i < conf.writer_given; i++) {
                void *wconf;
                int writer_num;
                ret = parse_stream_command(conf.writer_arg[i], &cmd);
                if (ret < 0)
                        goto out;
                a = &afi[ret];
                nw = a->num_writers;
                wconf = check_writer_arg(cmd, &writer_num);
                if (!wconf) {
                        ret = writer_num;
                        goto out;
                }
                a->writers[nw] = &writers[writer_num];
                a->writer_conf[nw] = wconf;
                PARA_INFO_LOG("%s writer #%d: %s\n", audio_formats[ret],
                        nw, writer_names[writer_num]);
                a->num_writers++;
        }
        ret = 1;
out:
        return ret;
}

static int init_receivers(void)
{
        int i, ret, receiver_num;
        char *cmd = NULL;
        struct audio_format_info *a;

        for (i = 0; receivers[i].name; i++) {
                PARA_INFO_LOG("initializing %s receiver\n", receivers[i].name);
                receivers[i].init(&receivers[i]);
        }
        for (i = conf.receiver_given - 1; i >= 0; i--) {
                char *arg = conf.receiver_arg[i];
                char *recv_arg = strchr(arg, ':');
                ret = -E_MISSING_COLON;
                if (!recv_arg)
                        goto out;
                *recv_arg = '\0';
                recv_arg++;
                ret = get_audio_format_num(arg);
                if (ret < 0)
                        goto out;
                afi[ret].receiver_conf = check_receiver_arg(recv_arg, &receiver_num);
                if (!afi[ret].receiver_conf) {
                        ret = -E_RECV_SYNTAX;
                        goto out;
                }
                afi[ret].receiver = &receivers[receiver_num];
        }
        /* use the first available receiver with no arguments
         * for those audio formats for which no receiver
         * was specified
         */
        cmd = para_strdup(receivers[0].name);
        FOR_EACH_AUDIO_FORMAT(i) {
                a = &afi[i];
                if (a->receiver_conf)
                        continue;
                a->receiver_conf = check_receiver_arg(cmd, &receiver_num);
                if (!a->receiver_conf)
                        return -E_RECV_SYNTAX;
                a->receiver = &receivers[receiver_num];
        }
        ret = 1;
out:
        free(cmd);
        return ret;
}

static int init_default_filters(void)
{
        int i, ret = 1;

        FOR_EACH_AUDIO_FORMAT(i) {
                struct audio_format_info *a = &afi[i];
                char *tmp;
                int j;

                if (a->num_filters)
                        continue; /* no default -- nothing to to */
                /* add "dec" to audio format name */
                tmp = make_message("%sdec", audio_formats[i]);
                for (j = 0; filters[j].name; j++)
                        if (!strcmp(tmp, filters[j].name))
                                break;
                free(tmp);
                ret = -E_UNSUPPORTED_FILTER;
                if (!filters[j].name)
                        goto out;
                tmp = para_strdup(filters[j].name);
                ret = add_filter(i, tmp);
                free(tmp);
                if (ret < 0)
                        goto out;
                PARA_INFO_LOG("%s -> default filter: %s\n", audio_formats[i],
                        filters[j].name);
        }
out:
        return ret;
}

static int init_filters(void)
{
        int i, ret, nf;

        filter_init(filters);
        nf = PARA_MAX(1U, conf.filter_given);
        PARA_INFO_LOG("maximal number of filters: %d\n", nf);
        FOR_EACH_AUDIO_FORMAT(i) {
                afi[i].filter_conf = para_malloc(nf * sizeof(void *));
                afi[i].filter_nums = para_malloc(nf * sizeof(unsigned));
        }
        if (!conf.no_default_filters_given)
                return init_default_filters();
        for (i = 0; i < conf.filter_given; i++) {
                char *arg = conf.filter_arg[i];
                char *filter_name = strchr(arg, ':');
                ret = -E_MISSING_COLON;
                if (!filter_name)
                        goto out;
                *filter_name = '\0';
                filter_name++;
                ret = get_audio_format_num(arg);
                if (ret < 0)
                        goto out;
                ret = add_filter(ret, filter_name);
                if (ret < 0)
                        goto out;
        }
        ret = init_default_filters(); /* use default values for the rest */
out:
        return ret;
}

static int init_stream_io(void)
{
        int ret;

        ret = init_writers();
        if (ret < 0)
                return ret;
        ret = init_receivers();
        if (ret < 0)
                return ret;
        ret = init_filters();
        if (ret < 0)
                return ret;
        return 1;
}

/* does not unlink socket on errors */
static int audiod_get_socket(void)
{
        struct sockaddr_un unix_addr;
        int ret, fd;

        if (conf.socket_given)
                socket_name = para_strdup(conf.socket_arg);
        else {
                char *hn = para_hostname();
                socket_name = make_message("/var/paraslash/audiod_socket.%s",
                        hn);
                free(hn);
        }
        PARA_NOTICE_LOG("local socket: %s\n", socket_name);
        if (conf.force_given)
                unlink(socket_name);
        ret = create_local_socket(socket_name, &unix_addr,
                S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IWOTH);
        if (ret < 0)
                goto err;
        fd = ret;
        if (listen(fd , 5) < 0) {
                ret = -ERRNO_TO_PARA_ERROR(errno);
                goto err;
        }
        ret = mark_fd_nonblocking(fd);
        if (ret < 0)
                goto err;
        return fd;
err:
        PARA_EMERG_LOG("%s\n", para_strerror(-ret));
        exit(EXIT_FAILURE);
}

static void signal_pre_select(struct sched *s, struct task *t)
{
        struct signal_task *st = container_of(t, struct signal_task, task);
        para_fd_set(st->fd, &s->rfds, &s->max_fileno);
}

static void signal_post_select(struct sched *s, struct task *t)
{
        struct signal_task *st = container_of(t, struct signal_task, task);

        if (!FD_ISSET(st->fd, &s->rfds))
                return;

        st->signum = para_next_signal();
        switch (st->signum) {
        case SIGINT:
        case SIGTERM:
        case SIGHUP:
                PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
                clean_exit(EXIT_FAILURE, "caught deadly signal");
        }
}

static void signal_setup_default(struct signal_task *st)
{
        st->task.pre_select = signal_pre_select;
        st->task.post_select = signal_post_select;
        sprintf(st->task.status, "signal task");
}

static void command_pre_select(struct sched *s, struct task *t)
{
        struct command_task *ct = container_of(t, struct command_task, task);
        para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
}

static void command_post_select(struct sched *s, struct task *t)
{
        int ret;
        struct command_task *ct = container_of(t, struct command_task, task);

        audiod_status_dump();
        if (!FD_ISSET(ct->fd, &s->rfds))
                return;
        ret = handle_connect(ct->fd);
        if (ret < 0)
                PARA_ERROR_LOG("%s\n", para_strerror(-ret));
}

static void init_command_task(struct command_task *ct)
{
        ct->task.pre_select = command_pre_select;
        ct->task.post_select = command_post_select;
        ct->task.error = 0;
        ct->fd = audiod_get_socket(); /* doesn't return on errors */
        sprintf(ct->task.status, "command task");
}

static void close_stat_pipe(void)
{
        int i;

        if (!stat_task->ct)
                return;
        client_close(stat_task->ct);
        stat_task->ct = NULL;
        FOR_EACH_STATUS_ITEM(i) {
                free(stat_item_values[i]);
                stat_item_values[i] = NULL;
        }
        dump_empty_status();
        stat_task->length_seconds = 0;
        stat_task->offset_seconds = 0;
        audiod_status_dump();
        stat_task->playing = 0;
}

/**
 * close the connection to para_server and exit
 *
 * \param status the exit status which is passed to exit(3)
 * \param msg the log message
 *
 * Log \a msg with loglevel \p EMERG, close the connection to para_server if
 * open, and call \p exit(status). \a status should be either EXIT_SUCCESS or
 * EXIT_FAILURE.
 *
 * \sa exit(3)
 */
void __noreturn clean_exit(int status, const char *msg)
{
        PARA_EMERG_LOG("%s\n", msg);
        if (socket_name)
                unlink(socket_name);
        close_stat_pipe();
        exit(status);
}

/* avoid busy loop if server is down */
static void set_stat_task_restart_barrier(unsigned seconds)
{
        struct timeval delay = {seconds, 0};
        tv_add(now, &delay, &stat_task->restart_barrier);
}

static void try_to_close_slot(int slot_num)
{
        struct slot_info *s = &slot[slot_num];

        if (s->format < 0)
                return;
        if (s->receiver_node && s->receiver_node->task.error != -E_TASK_UNREGISTERED)
                return;
        if (s->fc && s->fc->task.error != -E_TASK_UNREGISTERED)
                return;
        if (s->wng && s->wng->task.error != -E_TASK_UNREGISTERED)
                return;
        PARA_INFO_LOG("closing slot %d\n", slot_num);
        wng_close(s->wng);
        close_filters(s->fc);
        free(s->fc);
        close_receiver(slot_num);
        clear_slot(slot_num);
}

/*
 * Check if any receivers/filters/writers need to be started and do so if
 * necessary.
 */
static void start_stop_decoders(struct sched *s)
{
        int i;

        FOR_EACH_SLOT(i)
                try_to_close_slot(i);
        if (audiod_status != AUDIOD_ON || !stat_task->playing)
                return kill_all_decoders(-E_NOT_PLAYING);
        open_current_receiver(s);
        FOR_EACH_SLOT(i) {
                struct slot_info *sl = &slot[i];
                struct audio_format_info *a;
                struct timeval diff;

                if (sl->format < 0)
                        continue;
                a = &afi[sl->format];
                if (!sl->receiver_node)
                        continue;
                if ((!a->num_filters || sl->fc) && sl->wng)
                        continue; /* everything already started */
                if (!a->num_filters) {
                        if (sl->receiver_node->loaded && !sl->wng) {
                                open_writers(i);
                        }
                        continue;
                }
                if (sl->receiver_node->loaded && !sl->fc) {
                        open_filters(i);
                        continue;
                }
                if (sl->wng || !sl->fc || !*sl->fc->out_loaded)
                        continue;
                if (tv_diff(now, &initial_delay_barrier, &diff) > 0) {
                        open_writers(i);
                        continue;
                }
                PARA_INFO_LOG("initial delay: %lu ms left\n", tv2ms(&diff));
                if (tv_diff(&s->timeout, &diff, NULL) > 0) {
                        s->timeout = diff;
                }
        }
}


/* restart the client task if necessary */
static void status_pre_select(struct sched *s, struct task *t)
{
        struct status_task *st = container_of(t, struct status_task, task);

        if (audiod_status == AUDIOD_OFF) {
                if (!st->ct)
                        goto out;
                if (st->ct->task.error >= 0) {
                        st->ct->task.error = -E_AUDIOD_OFF;
                        goto out;
                }
                if (st->ct->task.error != -E_TASK_UNREGISTERED)
                        goto out;
                close_stat_pipe();
                st->clock_diff_count = conf.clock_diff_count_arg;
                goto out;
        }
        if (st->ct) {
                unsigned bytes_left;
                if (st->ct->task.error < 0) {
                        if (st->ct->task.error != -E_TASK_UNREGISTERED)
                                goto out;
                        close_stat_pipe();
                        goto out;
                }
                if (st->ct->status != CL_RECEIVING)
                        goto out;
                bytes_left = for_each_line(st->ct->buf, st->ct->loaded,
                        &check_stat_line, NULL);
                if (st->ct->loaded != bytes_left) {
                        st->last_status_read = *now;
                        st->ct->loaded = bytes_left;
                } else {
                        struct timeval diff;
                        tv_diff(now, &st->last_status_read, &diff);
                        if (diff.tv_sec > 61)
                                st->ct->task.error = -E_STATUS_TIMEOUT;
                }
                goto out;
        }
        if (tv_diff(now, &st->restart_barrier, NULL) < 0)
                goto out;
        if (st->clock_diff_count) { /* get status only one time */
                char *argv[] = {"audiod", "stat", "1", NULL};
                int argc = 3;
                PARA_INFO_LOG("clock diff count: %d\n", st->clock_diff_count);
                st->clock_diff_count--;
                client_open(argc, argv, &st->ct);
                set_stat_task_restart_barrier(2);

        } else {
                char *argv[] = {"audiod", "stat", NULL};
                int argc = 2;
                client_open(argc, argv, &st->ct);
                set_stat_task_restart_barrier(5);
        }
        free(stat_item_values[SI_BASENAME]);
        stat_item_values[SI_BASENAME] = make_message(
                "%s: no connection to para_server\n",
                status_item_list[SI_BASENAME]);
        stat_client_write(stat_item_values[SI_BASENAME],
                SI_BASENAME);
        st->last_status_read = *now;
out:
        start_stop_decoders(s);
}

static void init_status_task(struct status_task *st)
{
        memset(st, 0, sizeof(struct status_task));
        st->task.pre_select = status_pre_select;
        st->sa_time_diff_sign = 1;
        st->clock_diff_count = conf.clock_diff_count_arg;
        st->current_audio_format_num = -1;
        sprintf(st->task.status, "status task");
}

static void set_initial_status(void)
{
        audiod_status = AUDIOD_ON;
        if (!conf.mode_given)
                return;
        if (!strcmp(conf.mode_arg, "sb")) {
                audiod_status = AUDIOD_STANDBY;
                return;
        }
        if (!strcmp(conf.mode_arg, "off")) {
                audiod_status = AUDIOD_OFF;
                return;
        }
        if (strcmp(conf.mode_arg, "on"))
                PARA_WARNING_LOG("invalid mode\n");
}

/**
 * the main function of para_audiod
 *
 * \param argc usual argument count
 * \param argv usual argument vector
 *
 * \return EXIT_SUCCESS or EXIT_FAILURE
 *
 * \sa para_audiod(1)
 * */
int main(int argc, char *argv[])
{
        char *config_file;
        int ret, i;
        static struct sched s;
        struct command_task command_task_struct, *cmd_task = &command_task_struct;
        struct audiod_cmdline_parser_params params = {
                .override = 0,
                .initialize = 1,
                .check_required = 0,
                .check_ambiguity = 0,
                .print_errors = 1
        };

        valid_fd_012();
        audiod_cmdline_parser_ext(argc, argv, &conf, &params);
        HANDLE_VERSION_FLAG("audiod", conf);
        para_drop_privileges(conf.user_arg, conf.group_arg);
        config_file = configfile_exists();
        if (config_file) {
                params.override = 0;
                params.initialize = 0;
                params.check_required = 1;
                params.check_ambiguity = 0;
                params.print_errors = 1;
                if (audiod_cmdline_parser_config_file(config_file, &conf, &params)) {
                        PARA_EMERG_LOG("parse error in config file\n");
                        exit(EXIT_FAILURE);
                }
                free(config_file);
        }
        if (conf.logfile_given)
                logfile = open_log(conf.logfile_arg);
        log_welcome("para_audiod", conf.loglevel_arg);
        i = init_stream_io();
        if (i < 0) {
                PARA_EMERG_LOG("init stream io error: %s\n", para_strerror(-i));
                exit(EXIT_FAILURE);
        }
        server_uptime(UPTIME_SET);
        set_initial_status();
        FOR_EACH_SLOT(i)
                clear_slot(i);
        init_grabbing();
        setup_signal_handling();
        signal_setup_default(sig_task);

        init_status_task(stat_task);
        init_command_task(cmd_task);

        if (conf.daemon_given)
                daemon_init();

        register_task(&sig_task->task);
        register_task(&cmd_task->task);
        register_task(&stat_task->task);
        s.default_timeout.tv_sec = 0;
        s.default_timeout.tv_usec = 99 * 1000;
        ret = schedule(&s);

        PARA_EMERG_LOG("%s\n", para_strerror(-ret));
        return EXIT_FAILURE;
}