revert recent css changes
[paraslash.git] / audiod.c
index ede35ab..032f9cd 100644 (file)
--- a/audiod.c
+++ b/audiod.c
 
 /** \file audiod.c the paraslash's audio daemon */
 
-#include <sys/time.h> /* gettimeofday */
 #include "para.h"
 
 #include "audiod.cmdline.h"
 #include "list.h"
 #include "close_on_fork.h"
+#include "sched.h"
 #include "recv.h"
 #include "filter.h"
 #include "grab_client.cmdline.h"
 #include "grab_client.h"
-#include "ringbuffer.h"
 
 #include "error.h"
 #include "audiod.h"
 #include "net.h"
 #include "daemon.h"
 #include "string.h"
+#include "fd.h"
+#include "write.h"
+#include "write_common.h"
 
 /** define the array of error lists needed by para_audiod */
 INIT_AUDIOD_ERRLISTS;
 /** define the array containing all supported audio formats */
 DEFINE_AUDIO_FORMAT_ARRAY;
 
-/**
- * the possible modes of operation
- *
- * - off: disconnect from para_server
- * - on: receive status information from para_server and play the audio stream
- * - sb: only receive status information but not the audio stream
-*/
-enum {AUDIOD_OFF, AUDIOD_ON, AUDIOD_STANDBY};
-
 /** defines how to handle one supported audio format */
 struct audio_format_info {
-/** pointer to the receiver for this audio format */
+       /** pointer to the receiver for this audio format */
        struct receiver *receiver;
-/** the receiver configuration */
+       /** the receiver configuration */
        void *receiver_conf;
-/** the number of filters that should be activated for this audio format */
+       /** the number of filters that should be activated for this audio format */
        unsigned int num_filters;
-/** pointer to the array of filters to be activated */
+       /** pointer to the array of filters to be activated */
        struct filter **filters;
-/** pointer to the array of filter configurations */
+       /** pointer to the array of filter configurations */
        void **filter_conf;
-/** output of the last filter is written to stdin of this command */
-       char *write_cmd;
-/** do not start receiver/filters/writer before this time */
+       /** 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;
 };
 
-/**
- * describes one instance of a receiver-filter-writer chain
- *
- * \sa receier_node, receiver, filter, filter_node, filter_chain_info
-  */
-struct slot_info {
-/** number of the audio format in this slot */
-       int format;
-/** the file descriptor of the writer */
-       int write_fd;
-/** the process id of the writer */
-       pid_t wpid;
-/** time of the last successful read from the receiver */
-       struct timeval rtime;
-/** time the last write to the write fd happend */
-       struct timeval wtime;
-/** writer start time */
-       struct timeval wstime;
-/** did we include \a write_fd in the fdset */
-       int  wcheck;
-/** set to one if we have sent the TERM signal to \a wpid */
-       int wkilled;
-/** the receiver info associated with this slot */
-       struct receiver_node *receiver_node;
-/** the active filter chain */
-       struct filter_chain_info *fci;
-};
-
-static struct slot_info slot[MAX_STREAM_SLOTS];
-
-/** defines one command of para_audiod */
-struct audiod_command {
-/** the name of the command */
-const char *name;
-/** pointer to the function that handles the command */
-int (*handler)(int, int, char**);
-/** one-line description of the command */
-const char *description;
-/** summary of the command line options */
-const char *synopsis;
-/** the long help text */
-const char *help;
-};
-
-extern const char *status_item_list[NUM_STAT_ITEMS];
-
-static int com_grab(int, int, char **);
-static int com_cycle(int, int, char **);
-static int com_help(int, int, char **);
-static int com_off(int, int, char **);
-static int com_on(int, int, char **);
-static int com_sb(int, int, char **);
-static int com_stat(int, int, char **);
-static int com_term(int, int, char **);
-static int stat_pipe = -1, signal_pipe;
-
-static struct gengetopt_args_info conf;
-static struct timeval server_stream_start, sa_time_diff;
-static int playing, current_decoder = -1,
-       audiod_status = AUDIOD_ON, offset_seconds, length_seconds,
-       sa_time_diff_sign = 1, audiod_socket = -1;
-static char *af_status, /* the audio format announced in server status */
-       *socket_name, *hostname;
-/** how many status items to remember */
-#define RINGBUFFER_SIZE 32
-static void *stat_item_ringbuf;
-static FILE *logfile;
-static const struct timeval restart_delay = {0, 300 * 1000};
-
-static struct audio_format_info afi[] = {
-
-[AUDIO_FORMAT_MP3] =
-       {
-               .write_cmd = "para_play",
-       },
-[AUDIO_FORMAT_OGG] =
-       {
-               .write_cmd = "para_play",
-       },
-};
-
-static struct audiod_command cmds[] = {
-{
-.name = "cycle",
-.handler = com_cycle,
-.description = "switch to next mode",
-.synopsis = "cycle",
-.help =
-
-"on -> standby -> off -> on\n"
-
-},
-{
-.name = "grab",
-.handler = com_grab,
-.description = "grab the audio stream",
-.synopsis = "-- grab [grab_options]",
-.help =
-"grab ('splice') the audio stream at any position in the filter      \n"
-"chain and send that data back to the client. \n"
-"Available options:\n\n"
-GRAB_HELP_TXT
-},
-{
-.name = "help",
-.handler = com_help,
-.description = "display command list or help for given command",
-.synopsis = "help [command]",
-.help =
-
-"When I was younger, so much younger than today, I never needed\n"
-"anybody's help in any way. But now these days are gone, I'm not so\n"
-"self assured. Now I find I've changed my mind and opened up the doors.\n"
-"\n"
-"                              -- Beatles: Help\n"
-
-},
-{
-.name = "off",
-.handler = com_off,
-.description = "deactivate para_audiod",
-.synopsis = "off",
-.help =
+struct slot_info slot[MAX_STREAM_SLOTS];
 
-"Close connection to para_server and stop all decoders.\n"
 
-},
-{
-.name = "on",
-.handler = com_on,
-.description = "activate para_audiod",
-.synopsis = "on",
-.help =
-
-"Establish connection to para_server, retrieve para_server's current\n"
-"status. If playing, start corresponding decoder. Otherwise stop\n"
-"all decoders.\n"
-
-},
-{
-.name = "sb",
-.handler = com_sb,
-.description = "enter standby mode",
-.synopsis = "sb",
-.help =
-
-"Stop all decoders but leave connection to para_server open.\n"
+int audiod_status = AUDIOD_ON;
 
-},
-{
-.name = "stat",
-.handler = com_stat,
-.description = "print status information",
-.synopsis = "stat",
-.help =
+struct gengetopt_args_info conf;
+static char *socket_name;
+static FILE *logfile;
+static struct audio_format_info afi[NUM_AUDIO_FORMATS];
 
-"Add para_audiod status information to para_server's status information\n"
-"and dump everything to stdout.\n"
+static struct signal_task signal_task_struct, *sig_task = &signal_task_struct;
 
-},
-{
-.name = "term",
-.handler = com_term,
-.description = "terminate audiod",
-.synopsis = "term",
-.help =
+static struct status_task status_task_struct;
+struct status_task *stat_task = &status_task_struct;
 
-"Stop all decoders, shut down connection to para_server and exit.\n"
+/**
+ * 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;
+};
 
-},
-{
-.name = NULL,
-}
+struct signal_task {
+       int fd;
+       int signum;
+       struct task task;
 };
 
-/** iterate over all slots */
-#define FOR_EACH_SLOT(slot) for (slot = 0; slot < MAX_STREAM_SLOTS; slot++)
 /** iterate over all supported audio formats */
 #define FOR_EACH_AUDIO_FORMAT(af) for (af = 0; af < NUM_AUDIO_FORMATS; af++)
-/** iterate over the array of all audiod commands */
-#define FOR_EACH_COMMAND(c) for (c = 0; cmds[c].name; c++)
 
 /**
  * get the audio format number
@@ -269,27 +120,20 @@ int get_audio_format_num(char *name)
 /*
  * log function. first argument is loglevel.
  */
-void para_log(int ll, char* fmt,...)
+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.logfile_given)
-               logfile = open_log(conf.logfile_arg);
-       if (!logfile && conf.daemon_given)
-               return;
-       if (!logfile) {
-               if (ll < WARNING)
-                       outfd = stdout;
-               else
-                       outfd = stderr;
-       } else
-               outfd = logfile;
+       if (!hostname)
+               hostname = para_hostname();
+       outfd = logfile? logfile : stderr;
        time(&t1);
        tm = localtime(&t1);
        strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
@@ -301,97 +145,6 @@ void para_log(int ll, char* fmt,...)
        va_end(argp);
 }
 
-static int client_write(int fd, const char *buf)
-{
-       size_t len = strlen(buf);
-       return write(fd, buf, len) != len? -E_CLIENT_WRITE: 1;
-}
-
-static char *get_time_string(struct timeval *newest_stime)
-{
-       struct timeval now, diff, adj_stream_start, tmp;
-       int total = 0, use_server_time = 1;
-
-       if (!playing)
-               return make_message("%s:", length_seconds?
-                       "" : status_item_list[SI_PLAY_TIME]);
-       if (audiod_status == AUDIOD_OFF)
-               goto out;
-       if (sa_time_diff_sign > 0)
-               tv_diff(&server_stream_start, &sa_time_diff,
-                       &adj_stream_start);
-       else
-               tv_add(&server_stream_start, &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;
-               }
-       }
-       gettimeofday(&now, NULL);
-       tv_diff(&now, &tmp, &diff);
-       total = diff.tv_sec + 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)",
-               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
-       );
-}
-
-static char *audiod_status_string(void)
-{
-       int i;
-       struct timeval *newest_stime = NULL;
-       char *ret, *time_string, *uptime_string, *decoder_flags =
-               para_malloc((MAX_STREAM_SLOTS + 1) * sizeof(char));
-
-       FOR_EACH_SLOT(i) {
-               struct slot_info *s = &slot[i];
-               char flag = '0';
-               if (s->receiver_node)
-                       flag += 1;
-               if (s->wpid > 0)
-                       flag += 2;
-               if (flag != '0')
-                       flag += s->format * 4;
-               decoder_flags[i] = flag;
-               if (s->wpid <= 0)
-                       continue;
-               if (newest_stime && tv_diff(&s->wstime, newest_stime, NULL) <= 0)
-                       continue;
-               newest_stime = &s->wstime;
-       }
-       decoder_flags[MAX_STREAM_SLOTS] = '\0';
-       time_string = get_time_string(newest_stime);
-       uptime_string = uptime_str();
-       ret = make_message("%s:%s\n%s:%s\n%s:%s\n%s",
-               status_item_list[SI_AUDIOD_UPTIME], uptime_string,
-               status_item_list[SI_DECODER_FLAGS], decoder_flags,
-               status_item_list[SI_AUDIOD_STATUS], audiod_status == AUDIOD_ON?
-                       "on" : (audiod_status == AUDIOD_OFF? "off": "sb"),
-               time_string);
-       free(uptime_string);
-       free(decoder_flags);
-       free(time_string);
-       return ret;
-}
-
 static char *configfile_exists(void)
 {
        static char *config_file;
@@ -406,24 +159,14 @@ static char *configfile_exists(void)
 
 static void setup_signal_handling(void)
 {
-       signal_pipe = para_signal_init();
-       PARA_INFO_LOG("signal pipe: fd %d\n", signal_pipe);
+       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(SIGCHLD);
        para_install_sighandler(SIGHUP);
-       signal(SIGPIPE, SIG_IGN);
-}
-
-static void audiod_status_dump(void)
-{
-       static char *prev_status;
-       char *tmp = audiod_status_string();
-
-       if (!prev_status || strcmp(tmp, prev_status))
-               stat_client_write(tmp);
-       free(prev_status);
-       prev_status = tmp;
+       para_install_sighandler(SIGPIPE);
+//     signal(SIGPIPE, SIG_IGN);
 }
 
 static void clear_slot(int slot_num)
@@ -435,87 +178,49 @@ static void clear_slot(int slot_num)
        s->format = -1;
 }
 
-static void kill_stream_writer(int slot_num)
-{
-       struct slot_info *s = &slot[slot_num];
-
-       if (s->format < 0 || s->wkilled || s->wpid <= 0)
-               return;
-       PARA_DEBUG_LOG("kill -TERM %d (%s stream writer in slot %d)\n",
-               s->wpid, audio_formats[s->format], slot_num);
-       kill(s->wpid, SIGTERM);
-       s->wkilled = 1;
-       s->fci->error = 1;
-}
-
 static void close_receiver(int slot_num)
 {
        struct slot_info *s = &slot[slot_num];
        struct audio_format_info *a;
-       struct timeval now;
+       const struct timeval restart_delay = {0, 200 * 1000};
 
        if (s->format < 0 || !s->receiver_node)
                return;
        a = &afi[s->format];
-       PARA_NOTICE_LOG("closing %s recevier in slot %d\n",
-               audio_formats[s->format] , slot_num);
+       PARA_NOTICE_LOG("closing %s receiver in slot %d (eof = %d)\n",
+               audio_formats[s->format] , slot_num, s->receiver_node->eof);
+//     if (!s->receiver_node->eof)
+//             unregister_task(&s->receiver_node->task);
        a->receiver->close(s->receiver_node);
        free(s->receiver_node);
        s->receiver_node = NULL;
-       gettimeofday(&now, NULL);
-       tv_add(&now, &restart_delay, &a->restart_barrier); /* FIXME: Use set_restart_barrier() */
+       /* set restart barrier */
+       tv_add(now, &restart_delay, &afi[s->format].restart_barrier);
 }
 
 static void kill_all_decoders(void)
 {
        int i;
 
-       FOR_EACH_SLOT(i)
-               if (slot[i].format >= 0) {
-                       PARA_INFO_LOG("stopping decoder in slot %d\n", i);
-                       kill_stream_writer(i);
-               }
-}
-
-static void set_restart_barrier(int format, struct timeval *now)
-{
-       struct timeval tmp;
-
-       if (now)
-               tmp = *now;
-       else
-               gettimeofday(&tmp, NULL);
-       tv_add(&tmp, &restart_delay, &afi[format].restart_barrier);
-}
-
-static void check_sigchld(void)
-{
-       pid_t pid;
-       int i;
-       struct timeval now;
-       gettimeofday(&now, NULL);
-
-reap_next_child:
-       pid = para_reap_child();
-       if (pid <= 0)
-               return;
        FOR_EACH_SLOT(i) {
                struct slot_info *s = &slot[i];
-               long lifetime;
-               if (s->format < 0)
-                       continue;
-               if (pid == s->wpid) {
-                       s->wpid = -1;
-                       lifetime = now.tv_sec - s->wstime.tv_sec;
-                       PARA_INFO_LOG("%s stream writer in slot %d died "
-                               "after %li secs\n",
-                               audio_formats[s->format], i, lifetime);
-                       set_restart_barrier(s->format, &now);
-                       goto reap_next_child;
+               if (s->wng && !s->wng->eof) {
+                       PARA_INFO_LOG("unregistering writer node group in slot %d\n",
+                               i);
+                       wng_unregister(s->wng);
+                       s->wng->eof = 1;
+               }
+               if (s->fc && !s->fc->eof) {
+                       PARA_INFO_LOG("unregistering filter chain in slot %d\n", i);
+                       unregister_task(&s->fc->task);
+                       s->fc->eof = 1;
+               }
+               if (s->receiver_node && !s->receiver_node->eof) {
+                       PARA_INFO_LOG("unregistering receiver_node in slot %d\n", i);
+                       unregister_task(&s->receiver_node->task);
+                       s->receiver_node->eof = 1;
                }
        }
-       PARA_CRIT_LOG("para_client died (pid %d)\n", pid);
-       goto reap_next_child;
 }
 
 static int get_empty_slot(void)
@@ -529,11 +234,7 @@ static int get_empty_slot(void)
                        clear_slot(i);
                        return i;
                }
-               if (s->write_fd > 0 || s->wpid > 0)
-                       continue;
-               if (s->receiver_node)
-                       continue;
-               if (s->fci)
+               if (s->wng || s->receiver_node || s->fc)
                        continue;
                clear_slot(i);
                return i;
@@ -550,7 +251,7 @@ static int decoder_running(int format)
                s = &slot[i];
                if (s->format == format && s->receiver_node)
                        ret |= 1;
-               if (s->format == format && s->wpid > 0)
+               if (s->format == format && s->wng)
                        ret |= 2;
        }
        return ret;
@@ -558,73 +259,60 @@ static int decoder_running(int format)
 
 static void close_stat_pipe(void)
 {
-       char *msg;
        int i;
 
-       if (stat_pipe < 0)
+       if (stat_task->fd < 0)
                return;
        PARA_NOTICE_LOG("%s", "closing status pipe\n");
-       close(stat_pipe);
-       del_close_on_fork_list(stat_pipe);
-       stat_pipe = -1;
-       kill_all_decoders();
-       for (i = 0; i < RINGBUFFER_SIZE; i++)
-               ringbuffer_add(stat_item_ringbuf, para_strdup(NULL));
+       close(stat_task->fd);
+       del_close_on_fork_list(stat_task->fd);
+       stat_task->fd = -1;
+//     kill_all_decoders();
+       for (i = 0; i < NUM_STAT_ITEMS; i++) {
+               free(stat_task->stat_item_values[i]);
+               stat_task->stat_item_values[i] = NULL;
+       }
        dump_empty_status();
-       length_seconds = 0;
-       offset_seconds = 0;
+       stat_task->length_seconds = 0;
+       stat_task->offset_seconds = 0;
        audiod_status_dump();
-       playing = 0;
-       msg = make_message("%s:no connection to para_server\n",
+       stat_task->playing = 0;
+       stat_task->stat_item_values[SI_STATUS_BAR] = make_message(
+               "%s:no connection to para_server\n",
                status_item_list[SI_STATUS_BAR]);
-       ringbuffer_add(stat_item_ringbuf, msg);
-       stat_client_write(msg);
-       free(msg);
+       stat_client_write(stat_task->stat_item_values[SI_STATUS_BAR], SI_STATUS_BAR);
 }
 
-static void __noreturn clean_exit(int status, const char *msg)
+void __noreturn clean_exit(int status, const char *msg)
 {
        PARA_EMERG_LOG("%s\n", msg);
-       kill_all_decoders();
        if (socket_name)
                unlink(socket_name);
-       if (stat_pipe >= 0)
+       if (stat_task->fd >= 0)
                close_stat_pipe();
        exit(status);
 }
 
-static char *glob_cmd(char *cmd)
+/**
+ * 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)
 {
-       char *ret, *replacement;
-       struct timeval tmp, delay, rss; /* real stream start */
-
-       delay.tv_sec = conf.stream_delay_arg / 1000;
-       delay.tv_usec = (conf.stream_delay_arg % 1000) * 1000;
-//     PARA_INFO_LOG("delay: %lu:%lu\n", delay.tv_sec, delay.tv_usec);
-       if (sa_time_diff_sign < 0)
-               tv_add(&server_stream_start, &sa_time_diff, &rss);
-       else
-               tv_diff(&server_stream_start, &sa_time_diff, &rss);
-       tv_add(&rss, &delay, &tmp);
-       replacement = make_message("%lu:%lu", tmp.tv_sec, tmp.tv_usec);
-       ret = s_a_r(cmd, "STREAM_START", replacement);
-       free(replacement);
-       if (!ret)
-               goto out;
-       PARA_INFO_LOG("cmd: %s, repl: %s\n", cmd, ret);
-       {
-       struct timeval now;
-       gettimeofday(&now, NULL);
-       PARA_INFO_LOG("now: %lu:%lu\n", now.tv_sec, now.tv_usec);
-       }
-out:
-       return ret;
+       return afi[audio_format_num].num_filters;
 }
 
-/** get the number of filters for the given audio format */
-int num_filters(int audio_format_num)
+static void filter_event_handler(struct task *t)
 {
-       return afi[audio_format_num].num_filters;
+       PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-t->ret));
+       struct filter_chain *fc = t->private_data;
+       fc->eof = 1;
+       unregister_task(t);
 }
 
 static void open_filters(int slot_num)
@@ -634,81 +322,93 @@ static void open_filters(int slot_num)
        int nf = a->num_filters;
        int i;
 
-       s->fci = para_calloc(sizeof(struct filter_chain_info));
-       INIT_LIST_HEAD(&s->fci->filters);
+       s->fc = NULL;
        if (!nf)
                return;
-       s->fci->inbuf = s->receiver_node->buf;
-       s->fci->in_loaded = &s->receiver_node->loaded;
-       s->fci->outbuf = s->receiver_node->buf;
-       s->fci->out_loaded = &s->receiver_node->loaded;
-       s->fci->eof = &s->receiver_node->eof;
+       PARA_INFO_LOG("opening %s filters\n", audio_formats[s->format]);
+       s->fc = para_calloc(sizeof(struct filter_chain));
+       INIT_LIST_HEAD(&s->fc->filters);
+       s->fc->inbuf = s->receiver_node->buf;
+       s->fc->in_loaded = &s->receiver_node->loaded;
+       s->fc->input_eof = &s->receiver_node->eof;
+       s->fc->task.pre_select = filter_pre_select;
+       s->fc->task.event_handler = filter_event_handler;
+       s->fc->task.private_data = s->fc;
+       s->fc->eof = 0;
+
+       s->receiver_node->output_eof = &s->fc->eof;
+       sprintf(s->fc->task.status, "filter chain");
        for (i = 0; i < nf; i++) {
                struct filter_node *fn = para_calloc(sizeof(struct filter_node));
                fn->conf = a->filter_conf[i];
-               fn->fci = s->fci;
+               fn->fc = s->fc;
                fn->filter = a->filters[i];
                INIT_LIST_HEAD(&fn->callbacks);
-               list_add_tail(&fn->node, &s->fci->filters);
+               list_add_tail(&fn->node, &s->fc->filters);
                fn->filter->open(fn);
                PARA_NOTICE_LOG("%s filter %d/%d (%s) started in slot %d\n",
                        audio_formats[s->format], i + 1,  nf,
                        fn->filter->name, slot_num);
-               s->fci->outbuf = fn->buf;
-               s->fci->out_loaded = &fn->loaded;
+               s->fc->outbuf = fn->buf;
+               s->fc->out_loaded = &fn->loaded;
        }
-       PARA_DEBUG_LOG("output buffer for filter chain %p: %p\n", s->fci,
-               s->fci->outbuf);
+       register_task(&s->fc->task);
 }
 
-static struct filter_node *find_filter_node(int slot_num, int format, int filternum)
+static void wng_event_handler(struct task *t)
 {
-       struct filter_node *fn;
-       int i, j;
+       struct writer_node_group *wng = t->private_data;
 
-       FOR_EACH_SLOT(i) {
-               struct slot_info *s = &slot[i];
-               if (s->format < 0 || !s->fci)
-                       continue;
-               if (slot_num >= 0 && slot_num != i)
-                       continue;
-               if (format >= 0 && s->format != format)
-                       continue;
-               if (num_filters(i) < filternum)
-                       continue;
-               /* success */
-               j = 1;
-               list_for_each_entry(fn, &s->fci->filters, node)
-                       if (filternum <= 0 || j++ == filternum)
-                               break;
-               return fn;
-       }
-       return NULL;
+       PARA_INFO_LOG("%s\n", PARA_STRERROR(-t->ret));
+       wng->eof = 1;
+       wng_unregister(wng);
 }
 
-static void start_stream_writer(int slot_num)
+static void open_writers(int slot_num)
 {
-       int ret, fds[3] = {1, -1, -1};
+       int ret, i;
        struct slot_info *s = &slot[slot_num];
        struct audio_format_info *a = &afi[s->format];
-       char *glob = glob_cmd(a->write_cmd);
-
-       PARA_INFO_LOG("starting stream writer: %s\n", glob? glob : a->write_cmd);
-       open_filters(slot_num);
 
-       ret = para_exec_cmdline_pid(&s->wpid, glob? glob : a->write_cmd, fds);
-       free(glob);
+       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_eof = &s->fc->eof;
+               s->wng->channels = &s->fc->channels;
+               s->wng->samplerate = &s->fc->samplerate;
+               s->fc->output_eof = &s->wng->eof;
+               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_eof = &s->receiver_node->eof;
+       }
+       s->wng->task.event_handler = wng_event_handler;
+       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("exec failed (%d)\n", ret);
+               PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
                return;
        }
-       s->write_fd = fds[0];
-       add_close_on_fork_list(s->write_fd);
-       /* we write to this fd in do_select, so we need non-blocking */
-       fcntl(s->write_fd, F_SETFL, O_NONBLOCK);
-       gettimeofday(&s->wstime, NULL);
-       current_decoder = slot_num;
-       activate_inactive_grab_clients(slot_num, s->format, &s->fci->filters);
+       s->wstime = *now;
+       activate_inactive_grab_clients(slot_num, s->format, &s->fc->filters);
+}
+
+static void rn_event_handler(struct task *t)
+{
+       struct receiver_node *rn = t->private_data;
+
+       PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-t->ret));
+       unregister_task(t);
+       rn->eof = 1;
 }
 
 static void open_receiver(int format)
@@ -716,16 +416,17 @@ static void open_receiver(int format)
        struct audio_format_info *a = &afi[format];
        struct slot_info *s;
        int ret, slot_num;
+       struct receiver_node *rn;
 
        slot_num = get_empty_slot();
        if (slot_num < 0)
                clean_exit(EXIT_FAILURE, PARA_STRERROR(-slot_num));
        s = &slot[slot_num];
        s->format = format;
-       gettimeofday(&s->rtime, NULL);
-       s->wtime = s->rtime;
        s->receiver_node = para_calloc(sizeof(struct receiver_node));
-       s->receiver_node->conf = a->receiver_conf;
+       rn = s->receiver_node;
+       rn->receiver = a->receiver;
+       rn->conf = a->receiver_conf;
        ret = a->receiver->open(s->receiver_node);
        if (ret < 0) {
                PARA_ERROR_LOG("failed to open receiver (%s)\n",
@@ -736,105 +437,117 @@ static void open_receiver(int format)
        }
        PARA_NOTICE_LOG("started %s: %s receiver in slot %d\n",
                audio_formats[s->format], a->receiver->name, slot_num);
+       rn->task.private_data = s->receiver_node;
+       rn->task.pre_select = a->receiver->pre_select;
+       rn->task.post_select = a->receiver->post_select;
+       rn->task.event_handler = rn_event_handler;
+       sprintf(rn->task.status, "%s receiver node", rn->receiver->name);
+       register_task(&rn->task);
 }
 
-static int is_frozen(int format)
-{
-       struct timeval now;
-       struct audio_format_info *a = &afi[format];
-
-       gettimeofday(&now, NULL);
-       return (tv_diff(&now, &a->restart_barrier, NULL) > 0)? 0 : 1;
-}
-
-static void start_current_receiver(void)
+static int open_current_receiver(struct sched *s)
 {
        int i;
+       struct timeval diff;
 
-       if (!af_status)
-               return;
-       i = get_audio_format_num(af_status);
+       if (!stat_task->af_status)
+               return 0;
+       i = get_audio_format_num(stat_task->af_status);
        if (i < 0)
-               return;
-       if ((decoder_running(i) & 1) || is_frozen(i))
-               return;
+               return 0;
+       if (decoder_running(i))
+               return 0;
+       if (tv_diff(now, &afi[i].restart_barrier, &diff) < 0) {
+               s->timeout = diff;
+               return 0;
+       }
        open_receiver(i);
+       return 1;
 }
 
 static void compute_time_diff(const struct timeval *status_time)
 {
-       struct timeval now, tmp, diff;
+       struct timeval tmp, diff;
        static int count;
-       int sign;
+       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;
 
-       gettimeofday(&now, NULL);
-       sign = tv_diff(status_time, &now, &diff);
+       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;
-               sa_time_diff = diff;
+               stat_task->sa_time_diff = diff;
                count++;
                return;
        }
        if (count > 5) {
-               int s = tv_diff(&diff, &sa_time_diff, &tmp);
+               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, &sa_time_diff,
+               sa_time_diff_sign * time_smooth, &stat_task->sa_time_diff,
                count > 10? sign : sign * time_smooth, &diff,
                &tmp);
-       sa_time_diff = tmp;
-       PARA_INFO_LOG("time diff (cur/avg): "
-               "%li:%lu/%li:%lu\n",
-               sign * diff.tv_sec, (diff.tv_usec + 500) / 1000,
-               sa_time_diff_sign * sa_time_diff.tv_sec,
-               (sa_time_diff.tv_usec + 500)/ 1000);
+       stat_task->sa_time_diff = tmp;
+       PARA_DEBUG_LOG("time diff (cur/avg): %s%lums/%s%lums\n",
+               sign > 0? "+" : "-",
+               tv2ms(&diff),
+               sa_time_diff_sign ? "+" : "-",
+               tv2ms(&stat_task->sa_time_diff)
+       );
 }
 
 static void check_stat_line(char *line)
 {
        int itemnum;
        size_t ilen = 0;
-       struct timeval tv;
+       long unsigned sec, usec;
+       char *tmp;
 
+//     PARA_INFO_LOG("line: %s\n", line);
        if (!line)
                return;
-       ringbuffer_add(stat_item_ringbuf, line);
-       stat_client_write(line);
        itemnum = stat_line_valid(line);
-       if (itemnum < 0)
+       if (itemnum < 0) {
+               PARA_WARNING_LOG("invalid status line: %s\n", line);
                return;
+       }
+       tmp = make_message("%s\n", line);
+       stat_client_write(tmp, itemnum);
+       free(tmp);
+       free(stat_task->stat_item_values[itemnum]);
+       stat_task->stat_item_values[itemnum] = para_strdup(line);
        ilen = strlen(status_item_list[itemnum]);
        switch (itemnum) {
        case SI_STATUS:
-               playing = strstr(line, "playing")? 1 : 0;
+               stat_task->playing = strstr(line, "playing")? 1 : 0;
                break;
        case SI_FORMAT:
-               free(af_status);
-               af_status = para_strdup(line + ilen + 1);
+               free(stat_task->af_status);
+               stat_task->af_status = para_strdup(line + ilen + 1);
                break;
        case SI_OFFSET:
-               offset_seconds = atoi(line + ilen + 1);
+               stat_task->offset_seconds = atoi(line + ilen + 1);
                break;
        case SI_LENGTH:
-               length_seconds = atoi(line + ilen + 1);
+               stat_task->length_seconds = atoi(line + ilen + 1);
                break;
        case SI_STREAM_START:
-               if (sscanf(line + ilen + 1, "%lu.%lu",
-                               &tv.tv_sec, &tv.tv_usec) == 2)
-                       server_stream_start = tv;
+               if (sscanf(line + ilen + 1, "%lu.%lu", &sec, &usec) == 2) {
+                       stat_task->server_stream_start.tv_sec = sec;
+                       stat_task->server_stream_start.tv_usec = usec;
+               }
                break;
        case SI_CURRENT_TIME:
-               if (sscanf(line + ilen + 1, "%lu.%lu", &tv.tv_sec,
-                               &tv.tv_usec) == 2)
+               if (sscanf(line + ilen + 1, "%lu.%lu", &sec, &usec) == 2) {
+                       struct timeval tv = {sec, usec};
                        compute_time_diff(&tv);
+               }
                break;
        }
 }
@@ -843,7 +556,12 @@ static void handle_signal(int sig)
 {
        switch (sig) {
        case SIGCHLD:
-               return check_sigchld();
+               for (;;) {
+                       pid_t pid = para_reap_child();
+                       if (pid <= 0)
+                               return;
+                       PARA_CRIT_LOG("para_client died (pid %d)\n", pid);
+               }
        case SIGINT:
        case SIGTERM:
        case SIGHUP:
@@ -853,181 +571,88 @@ static void handle_signal(int sig)
        }
 }
 
-static void check_timeouts(void)
-{
-       struct timeval now;
-       int slot_num, timeout = conf.stream_timeout_arg;
-
-       gettimeofday(&now, NULL);
-       FOR_EACH_SLOT(slot_num) {
-               struct slot_info *s = &slot[slot_num];
-               if (s->format < 0)
-                       continue;
-               /* check read time */
-               if (s->receiver_node &&
-                       now.tv_sec > s->rtime.tv_sec + timeout) {
-                       PARA_INFO_LOG("%s input buffer (slot %d) not ready\n",
-                               audio_formats[s->format], slot_num);
-                       if (s->fci)
-                               s->fci->error = 42;
-                       else
-                               close_receiver(slot_num);
-               }
-               /* check write time */
-               if (s->wpid > 0 && !s->wkilled &&
-                       now.tv_sec > s->wtime.tv_sec + timeout) {
-                       PARA_INFO_LOG("%s output buffer (slot %d) not ready\n",
-                               audio_formats[s->format], slot_num);
-                       if (s->fci)
-                               s->fci->error = 42;
-               }
-       }
-}
-
-static size_t get_loaded_bytes(int slot_num)
+static void try_to_close_slot(int slot_num)
 {
-       size_t loaded = 0;
        struct slot_info *s = &slot[slot_num];
-       struct receiver_node *rn = s->receiver_node;
-
-       if (s->format < 0)
-               goto out;
-
-       if (afi[s->format].num_filters) {
-               if (s->fci)
-                       loaded = *s->fci->out_loaded;
-       } else {
-               if (rn)
-                       loaded = rn->loaded;
-       }
-out:
-       return loaded;
-}
-
-
-static void close_decoder_if_idle(int slot_num)
-{
-       struct slot_info *s = &slot[slot_num];
-       struct receiver_node *rn = s->receiver_node;
 
        if (s->format < 0)
                return;
-       if (!s->fci)
+       if (s->receiver_node && !s->receiver_node->eof)
                return;
-       if (!rn->eof && !s->fci->error && s->wpid > 0)
+       if (s->fc && !s->fc->eof)
                return;
-       if (!s->fci->error && s->wpid > 0) { /* eof */
-               if (filter_io(s->fci) > 0)
-                       return;
-               if (get_loaded_bytes(slot_num))
-                       return;
-       }
-       if (s->write_fd > 0) {
-               PARA_INFO_LOG("slot %d: closing write fd %d\n", slot_num,
-                       s->write_fd);
-               close(s->write_fd);
-               del_close_on_fork_list(s->write_fd);
-               s->write_fd = -1;
-       }
-       if (s->wpid > 0)
-               return; /* wait until writer dies before closing filters */
-       PARA_INFO_LOG("closing all filters in slot %d (filter_chain %p)\n",
-               slot_num, s->fci);
-       close_filters(s->fci);
-       free(s->fci);
+       if (s->wng && !s->wng->eof)
+               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);
 }
 
-static int set_stream_fds(fd_set *wfds)
+/*
+ * Check if any receivers/filters/writers need to be started and do so if
+ * neccessary.  Since the pre_select function didn't have a chance yet to put
+ * file descriptors into the fd sets given by s, make the upcoming select()
+ * return immediately to avoid a long timeout in case we started something.
+ */
+static void audiod_pre_select(struct sched *s, __a_unused struct task *t)
 {
-       int i, max_fileno = -1;
+       int i;
+       struct timeval min_delay = {0, 1};
 
-       check_timeouts();
+       t->ret = 1;
+       if (audiod_status != AUDIOD_ON || !stat_task->playing)
+               return kill_all_decoders();
+       if (open_current_receiver(s))
+               s->timeout = min_delay;
        FOR_EACH_SLOT(i) {
-               struct slot_info *s = &slot[i];
+               struct slot_info *sl = &slot[i];
                struct audio_format_info *a;
-               struct receiver_node *rn;
 
-               close_decoder_if_idle(i);
-               s->wcheck = 0;
-               if (s->format < 0)
+               if (sl->format < 0)
                        continue;
-               a = &afi[s->format];
-               rn = s->receiver_node;
-               if (rn && rn->loaded && !s->wpid) {
-                       PARA_INFO_LOG("no writer in slot %d\n", i);
-                       start_stream_writer(i);
-               }
-               if (s->write_fd <= 0)
+               a = &afi[sl->format];
+               if (!sl->receiver_node)
+                       continue;
+               if (!a->num_filters) {
+                       if (sl->receiver_node->loaded && !sl->wng) {
+                               open_writers(i);
+                               s->timeout = min_delay;
+                       }
                        continue;
-               if (!get_loaded_bytes(i))
+               }
+               if (sl->receiver_node->loaded && !sl->fc) {
+                       open_filters(i);
+                       s->timeout = min_delay;
                        continue;
-               FD_SET(s->write_fd, wfds);
-               s->wcheck = 1;
-               max_fileno = MAX(s->write_fd, max_fileno);
+               }
+               if (sl->fc && *sl->fc->out_loaded && !sl->wng) {
+                       open_writers(i);
+                       s->timeout = min_delay;
+               }
        }
-//     PARA_INFO_LOG("return %d\n", max_fileno);
-       return max_fileno;
 }
 
-static int write_audio_data(int slot_num)
+static void audiod_post_select(__a_unused struct sched *s,
+       __a_unused struct task *t)
 {
-       struct slot_info *s = &slot[slot_num];
-       struct audio_format_info *a = &afi[s->format];
-       struct receiver_node *rn = s->receiver_node;
-       int rv;
-       char **buf;
-       size_t *len;
-
-       if (a->num_filters) {
-               buf = &s->fci->outbuf;
-               len = s->fci->out_loaded;
-       } else {
-               buf = &rn->buf;
-               len = &rn->loaded;
-       }
-       PARA_DEBUG_LOG("writing %p (%d bytes)\n", *buf, *len);
-       rv = write(s->write_fd, *buf, *len);
-       PARA_DEBUG_LOG("wrote %d/%d\n", rv, *len);
-       if (rv < 0) {
-               PARA_WARNING_LOG("write error in slot %d (fd %d): %s\n",
-                       slot_num, s->write_fd, strerror(errno));
-               *len = 0;
-               s->fci->error = E_WRITE_AUDIO_DATA;
-       } else if (rv != *len) {
-               PARA_DEBUG_LOG("partial %s write (%i/%i) for slot %d\n",
-                       audio_formats[s->format], rv, *len, slot_num);
-               *len -= rv;
-               memmove(*buf, *buf + rv, *len);
-       } else
-               *len = 0;
-       if (rv > 0)
-               gettimeofday(&s->wtime, NULL);
-       return rv;
+       int i;
+
+       /* save away the current time for other users */
+       t->ret = 1;
+       FOR_EACH_SLOT(i)
+               try_to_close_slot(i);
 }
 
-static void slot_io(fd_set *wfds)
+static void init_audiod_task(struct task *t)
 {
-       int ret, i;
-
-       FOR_EACH_SLOT(i) {
-               struct slot_info *s = &slot[i];
-               struct receiver_node *rn = s->receiver_node;
-
-               if (rn && rn->loaded)
-                       gettimeofday(&s->rtime, NULL);
-               if (s->format >= 0 && s->write_fd > 0 && s->fci) {
-                       ret = filter_io(s->fci);
-                       if (ret < 0)
-                               s->fci->error = -ret;
-//                     PARA_DEBUG_LOG("slot %d, filter io %d bytes, check write: %d, loaded: %d/%d, eof: %d\n",
-//                              i, ret, s->wcheck, rn->loaded, *s->fci->out_loaded, rn->eof);
-               }
-               if (s->write_fd <= 0 || !s->wcheck || !FD_ISSET(s->write_fd, wfds))
-                       continue;
-               write_audio_data(i);
-       }
+       t->pre_select = audiod_pre_select;
+       t->post_select = audiod_post_select;
+       t->event_handler = NULL;
+       t->private_data = t;
+       sprintf(t->status, "audiod task");
 }
 
 static int parse_stream_command(const char *txt, char **cmd)
@@ -1062,52 +687,51 @@ static int add_filter(int format, char *cmdline)
        return filter_num;
 }
 
-static int setup_default_filters(void)
+static int init_writers(void)
 {
-       int i, ret = 1;
+       int i, ret, nw;
+       char *cmd;
+       struct audio_format_info *a;
 
+       init_supported_writers();
+       nw = PARA_MAX(1, conf.writer_given);
+       PARA_INFO_LOG("maximal number of writers: %d\n", nw);
        FOR_EACH_AUDIO_FORMAT(i) {
-               struct audio_format_info *a = &afi[i];
-               char *tmp;
-               int j;
-               if (a->num_filters)
-                       continue;
-               /* 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);
+               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;
-               PARA_INFO_LOG("%s -> default filter: %s\n", audio_formats[i], filters[j].name);
-               ret = add_filter(i, "wav");
-               if (ret < 0)
+               a = &afi[ret];
+               nw = a->num_writers;
+               wconf = check_writer_arg(cmd, &writer_num);
+               if (!wconf) {
+                       ret = writer_num;
                        goto out;
-               PARA_INFO_LOG("%s -> default filter: wav\n", audio_formats[i]);
+               }
+               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_stream_io(void)
+static int init_receivers(void)
 {
        int i, ret, receiver_num;
-       char *cmd;
+       char *cmd = NULL;
+       struct audio_format_info *a;
 
-       for (i = 0; i < conf.stream_write_cmd_given; i++) {
-               ret = parse_stream_command(conf.stream_write_cmd_arg[i], &cmd);
-               if (ret < 0)
-                       goto out;
-               afi[ret].write_cmd = para_strdup(cmd);
-               PARA_INFO_LOG("%s write command: %s\n", audio_formats[ret], afi[ret].write_cmd);
-       }
        for (i = 0; receivers[i].name; i++) {
                PARA_INFO_LOG("initializing %s receiver\n", receivers[i].name);
                receivers[i].init(&receivers[i]);
@@ -1136,7 +760,7 @@ static int init_stream_io(void)
         */
        cmd = para_strdup(receivers[0].name);
        FOR_EACH_AUDIO_FORMAT(i) {
-               struct audio_format_info *a = &afi[i];
+               a = &afi[i];
                if (a->receiver_conf)
                        continue;
                a->receiver_conf = check_receiver_arg(cmd, &receiver_num);
@@ -1144,15 +768,57 @@ static int init_stream_io(void)
                        return -E_RECV_SYNTAX;
                a->receiver = &receivers[receiver_num];
        }
+       ret = 1;
+out:
        free(cmd);
-       /* filters */
+       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(1,  conf.filter_given);
+       PARA_INFO_LOG("maximal number of filters: %d\n", nf);
        FOR_EACH_AUDIO_FORMAT(i) {
-               afi[i].filter_conf = para_malloc((conf.filter_given + 1) * sizeof(char *));
-               afi[i].filters = para_malloc((conf.filter_given + 1) * sizeof(struct filter *));
+               afi[i].filter_conf = para_malloc(nf * sizeof(void *));
+               afi[i].filters = para_malloc(nf * sizeof(struct filter *));
        }
        if (!conf.no_default_filters_given)
-               return setup_default_filters();
+               return init_default_filters();
        for (i = 0; i < conf.filter_given; i++) {
                char *arg = conf.filter_arg[i];
                char *filter_name = strchr(arg, ':');
@@ -1168,240 +834,31 @@ static int init_stream_io(void)
                if (ret < 0)
                        goto out;
        }
-       ret = 1;
+       ret = init_default_filters(); /* use default values for the rest */
 out:
        return ret;
 }
 
-static int dump_commands(int fd)
-{
-       char *buf = para_strdup(""), *tmp = NULL;
-       int i;
-       ssize_t ret;
-
-       FOR_EACH_COMMAND(i) {
-               tmp = make_message("%s%s\t%s\n", buf, cmds[i].name,
-                       cmds[i].description);
-               free(buf);
-               buf = tmp;
-       }
-       ret = client_write(fd, buf);
-       free(buf);
-       return ret;
-}
-
-/*
- * command handlers don't close their fd on errors (ret < 0) so that
- * its caller can send an error message. Otherwise (ret >= 0) it's up
- * to each individual command to close the fd if necessary.  
- */
-
-static int com_help(int fd, int argc, char **argv)
-{
-       int i, ret;
-       char *buf;
-       const char *dflt = "No such command. Available commands:\n";
-
-       if (argc < 2) {
-               ret = dump_commands(fd);
-               goto out;
-       }
-       FOR_EACH_COMMAND(i) {
-               if (strcmp(cmds[i].name, argv[1]))
-                       continue;
-               buf = make_message(
-                       "NAME\n\t%s -- %s\n"
-                       "SYNOPSIS\n\tpara_audioc %s\n"
-                       "DESCRIPTION\n%s\n",
-                       argv[1],
-                       cmds[i].description,
-                       cmds[i].synopsis,
-                       cmds[i].help
-               );
-               ret = client_write(fd, buf);
-               free(buf);
-               goto out;
-       }
-       ret = client_write(fd, dflt);
-       if (ret > 0)
-               ret = dump_commands(fd);
-out:
-       if (ret >= 0)
-               close(fd);
-       return ret;
-}
-
-static int com_stat(int fd, __unused int argc, __unused char **argv)
-{
-       int i, ret;
-       char *buf = audiod_status_string();
-
-       buf = para_strcat(buf, "\n");
-       for (i = RINGBUFFER_SIZE - 1; i >= 0; i--) {
-               char *tmp, *line = ringbuffer_get(stat_item_ringbuf, i);
-               if (!line)
-                       continue;
-               tmp = make_message("%s\n", line);
-               buf = para_strcat(buf, tmp);
-               free(tmp);
-       }
-       ret = client_write(fd, buf);
-       if (ret > 0)
-               ret = stat_client_add(fd);
-       free(buf);
-       return ret;
-}
-
-#if 0
-static char *list_filters(void)
-{
-       int i, j;
-       char *tmp, *msg = make_message("format\tnum\tcmd\n");
-
-       FOR_EACH_AUDIO_FORMAT(i) {
-               for (j = 0; j < afi[i].num_filters; j++) {
-                       tmp = make_message("%s\t%i\t%s\n",
-                               afi[i].name, j, afi[i].filter_cmds[j]);
-                       msg = para_strcat(msg, tmp);
-                       free(tmp);
-               }
-               tmp = make_message("%s\t%i\t%s\n", afi[i].name,
-                       j, afi[i].write_cmd);
-               msg = para_strcat(msg, tmp);
-               free(tmp);
-       }
-       return msg;
-}
-#endif
-
-static int com_grab(int fd, int argc, char **argv)
-{
-       struct grab_client *gc;
-       struct filter_node *fn;
-       int err;
-
-       PARA_INFO_LOG("argc: %d, argv[0]: %s, optind: %d\n", argc, argv[0], optind);
-       gc = grab_client_new(fd, argc, argv, &err);
-       PARA_INFO_LOG("argc: %d, argv[0]: %s, optind: %d\n", argc, argv[0], optind);
-       if (!gc)
-               goto err_out;
-       fn = find_filter_node(gc->conf->slot_arg, gc->audio_format_num, gc->conf->filter_num_arg);
-       if (fn)
-               activate_grab_client(gc, fn);
-       return 1;
-err_out:
-       if (err != -E_GC_HELP_GIVEN)
-               return err;
-       err = client_write(fd, "Usage: para_audioc [audioc_options] -- "
-               "grab [grab_options]\nAvailable options:\n");
-       if (err < 0)
-               return err;
-       err = client_write(fd, GRAB_HELP_TXT);
-       if (err < 0)
-               return err;
-       close(fd);
-       return 1;
-}
-
-static int __noreturn com_term(int fd, __unused int argc, __unused char **argv)
-{
-       close(fd);
-       clean_exit(EXIT_SUCCESS, "terminating on user request");
-}
-
-static int com_on(int fd, __unused int argc, __unused char **argv)
-{
-       audiod_status = AUDIOD_ON;
-       close(fd);
-       return 1;
-}
-
-static int com_off(int fd, __unused int argc, __unused char **argv)
-{
-       audiod_status = AUDIOD_OFF;
-       close(fd);
-       return 1;
-}
-
-static int com_sb(int fd, __unused int argc, __unused char **argv)
-{
-       audiod_status = AUDIOD_STANDBY;
-       close(fd);
-       return 1;
-}
-
-static int com_cycle(int fd, int argc, char **argv)
-{
-       switch (audiod_status) {
-               case  AUDIOD_ON:
-                       return com_sb(fd, argc, argv);
-                       break;
-               case  AUDIOD_OFF:
-                       return com_on(fd, argc, argv);
-                       break;
-               case  AUDIOD_STANDBY:
-                       return com_off(fd, argc, argv);
-                       break;
-       }
-       close(fd);
-       return 1;
-}
-
-static int check_perms(struct ucred *c)
-{
-       int i;
-
-       if (!conf.user_allow_given)
-               return 1;
-       for (i = 0; i < conf.user_allow_given; i++)
-               if (c->uid == conf.user_allow_arg[i])
-                       return 1;
-       return -E_UCRED_PERM;
-}
-
-static int handle_connect(void)
+static int init_stream_io(void)
 {
-       int i, argc, ret, clifd = -1;
-       struct ucred c;
-       char *buf = para_malloc(MAXLINE), **argv = NULL;
-       struct sockaddr_un unix_addr;
+       int ret;
 
-       ret = para_accept(audiod_socket, &unix_addr, sizeof(struct sockaddr_un));
+       ret = init_writers();
        if (ret < 0)
-               goto out;
-       clifd = ret;
-       ret = recv_cred_buffer(clifd, buf, MAXLINE - 1, &c);
+               return ret;
+       ret = init_receivers();
        if (ret < 0)
-               goto out;
-       PARA_INFO_LOG("pid: %i, uid: %i, gid: %i, ret: %i, buf: %s\n", c.pid, c.uid, c.gid, ret, buf);
-       buf[ret] = '\0';
-       ret = check_perms(&c);
+               return ret;
+       ret = init_filters();
        if (ret < 0)
-               goto out;
-       argc = split_args(buf, &argv, '\n');
-       PARA_INFO_LOG("argv[0]: %s\n", argv[0]);
-       for (i = 0; cmds[i].name; i++) {
-               if (strcmp(cmds[i].name, argv[0]))
-                       continue;
-               ret = cmds[i].handler(clifd, argc + 1, argv);
-               goto out;
-       }
-       ret = -E_INVALID_AUDIOD_CMD; /* cmd not found */
-out:
-       free(buf);
-       free(argv);
-       if (clifd > 0 && ret < 0 && ret != -E_CLIENT_WRITE) {
-               char *tmp = make_message("%s\n", PARA_STRERROR(-ret));
-               client_write(clifd, tmp);
-               free(tmp);
-               close(clifd);
-       }
-       return ret;
+               return ret;
+       return 1;
 }
 
-static void audiod_get_socket(void)
+static int audiod_get_socket(void)
 {
        struct sockaddr_un unix_addr;
+       int fd;
 
        if (conf.socket_given)
                socket_name = para_strdup(conf.socket_arg);
@@ -1411,28 +868,28 @@ static void audiod_get_socket(void)
                        hn);
                free(hn);
        }
-       PARA_NOTICE_LOG("connecting to local socket %s\n", socket_name);
+       PARA_NOTICE_LOG("local socket: %s\n", socket_name);
        if (conf.force_given)
                unlink(socket_name);
-       audiod_socket = create_pf_socket(socket_name, &unix_addr,
+       fd = create_pf_socket(socket_name, &unix_addr,
                        S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IWOTH);
-       if (audiod_socket < 0) {
+       if (fd < 0) {
                PARA_EMERG_LOG("%s", "can not connect to socket\n");
                exit(EXIT_FAILURE); /* do not unlink socket */
        }
-       if (listen(audiod_socket, 5) < 0) {
+       if (listen(fd , 5) < 0) {
                PARA_EMERG_LOG("%s", "can not listen on socket\n");
                exit(EXIT_FAILURE); /* do not unlink socket */
        }
-       add_close_on_fork_list(audiod_socket);
+       add_close_on_fork_list(fd);
+       return fd;
 }
 
 static int open_stat_pipe(void)
 {
        int ret, fd[3] = {-1, 1, 0};
-       char *argv[] = {BINDIR "/para_client", "stat", NULL};
        pid_t pid;
-       ret = para_exec(&pid, BINDIR "/para_client",  argv, fd);
+       ret = para_exec_cmdline_pid(&pid, BINDIR "/para_client stat", fd);
        if (ret >= 0) {
                ret = fd[1];
                PARA_NOTICE_LOG("stat pipe opened, fd %d\n", ret);
@@ -1442,126 +899,132 @@ static int open_stat_pipe(void)
        return ret;
 }
 
-static int pre_select(fd_set *rfds, fd_set *wfds, struct timeval *tv)
+void signal_event_handler(struct task *t)
 {
-       int i, ret, max = -1;
+       struct signal_task *st = t->private_data;
 
-       FOR_EACH_SLOT(i) {
-               struct slot_info *s = &slot[i];
-               struct audio_format_info *a;
-               struct receiver_node *rn = s->receiver_node;
-               if (s->format < 0 || !rn)
-                       continue;
-               a = &afi[s->format];
-               ret = a->receiver->pre_select(rn, rfds, wfds, tv);
-//             PARA_NOTICE_LOG("%s preselect: %d\n", a->receiver->name, ret);
-               max = MAX(max, ret);
-       }
-       return max;
+       if (t->ret != -E_SIGNAL_CAUGHT)
+               PARA_ERROR_LOG("%s (ignored)\n", PARA_STRERROR(-t->ret));
+       else
+               handle_signal(st->signum);
+}
 
+void signal_pre_select(struct sched *s, struct task *t)
+{
+       struct signal_task *st = t->private_data;
+       t->ret = 1;
+       para_fd_set(st->fd, &s->rfds, &s->max_fileno);
 }
-static void audiod_post_select(int select_ret, fd_set *rfds, fd_set *wfds)
+
+void signal_post_select(struct sched *s, struct task *t)
 {
-       int i, ret;
+       struct signal_task *st = t->private_data;
+       t->ret = 1;
+       if (!FD_ISSET(st->fd, &s->rfds))
+               return;
+       t->ret = -E_SIGNAL_CAUGHT;
+       st->signum = para_next_signal();
+}
 
-       FOR_EACH_SLOT(i) {
-               struct slot_info *s = &slot[i];
-               struct audio_format_info *a;
-               struct receiver_node *rn = s->receiver_node;
-               if (s->format < 0 || !rn || rn->eof)
-                       continue;
-               a = &afi[s->format];
-               ret = a->receiver->post_select(rn, select_ret, rfds, wfds);
-               if (ret <= 0) {
-                       if (ret)
-                               PARA_ERROR_LOG("%s post select failed: %s (slot %d)\n",
-                               a->receiver->name, PARA_STRERROR(-ret), i);
-                       else
-                               PARA_INFO_LOG("eof in slot %d\n", i);
-                       rn->eof = 1;
-               }
-               if (ret < 0 && s->fci)
-                       s->fci->error = ret;
-       }
+void signal_setup_default(struct signal_task *st)
+{
+       st->task.pre_select = signal_pre_select;
+       st->task.post_select = signal_post_select;
+       st->task.private_data = st;
+       sprintf(st->task.status, "signal task");
 }
 
-/* TODO: move everything before the select call to pre_select() */
-static void __noreturn audiod_mainloop(void)
+static void command_pre_select(struct sched *s, struct task *t)
 {
-       fd_set rfds, wfds;
-       int ret, max_fileno, sbo = 0;
-       char status_buf[STRINGSIZE] = "";
-       struct timeval tv;
-repeat:
-       FD_ZERO(&rfds);
-       FD_ZERO(&wfds);
-       max_fileno = 0;
-       if (audiod_status != AUDIOD_ON)
-               kill_all_decoders();
-       else if (playing)
-               start_current_receiver();
-       max_fileno = set_stream_fds(&wfds);
-       /* stat pipe (read) */
-       if (stat_pipe >= 0 && audiod_status == AUDIOD_OFF)
-               close_stat_pipe();
-       if (stat_pipe < 0 && audiod_status != AUDIOD_OFF) {
-               stat_pipe = open_stat_pipe();
-               sbo = 0;
-               status_buf[0] = '\0';
-       }
-       if (stat_pipe >= 0 && audiod_status != AUDIOD_OFF) {
-               FD_SET(stat_pipe, &rfds);
-               max_fileno = MAX(max_fileno, stat_pipe);
-       }
-       /* always check signal pipe */
-       FD_SET(signal_pipe, &rfds);
-       max_fileno = MAX(max_fileno, signal_pipe);
-       /* local socket */
-       if (audiod_socket < 0)
-               audiod_get_socket(); /* doesn't return on errors */
-       FD_SET(audiod_socket, &rfds);
-       max_fileno = MAX(max_fileno, audiod_socket);
-       tv.tv_sec = 0;
-       tv.tv_usec = 200 * 1000;
-       ret = pre_select(&rfds, &wfds, &tv);
-       max_fileno = MAX(max_fileno, ret);
-       ret = select(max_fileno + 1, &rfds, &wfds, NULL, &tv);
-       if (ret < 0 && errno != EINTR)
-               PARA_ERROR_LOG("select returned %d (%s)\n", ret,
-                       strerror(errno));
+       struct command_task *ct = t->private_data;
+       t->ret = 1;
+       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 = t->private_data;
+
+       t->ret = 1; /* always successful */
        if (audiod_status != AUDIOD_OFF)
                audiod_status_dump();
+       if (!FD_ISSET(ct->fd, &s->rfds))
+               return;
+       ret = handle_connect(ct->fd);
        if (ret < 0)
-               goto repeat;
-       audiod_post_select(ret, &rfds, &wfds);
-       /* read status pipe */
-       if (stat_pipe >=0 && FD_ISSET(stat_pipe, &rfds)) {
-               ret = read(stat_pipe, status_buf + sbo, STRINGSIZE - 1 - sbo);
-               if (ret <= 0) {
-                       close_stat_pipe();
-                       /* avoid busy loop if server is down */
-                       while (sleep(1) > 0)
-                               ; /* try again*/
-               } else {
-                       status_buf[ret + sbo] = '\0';
-                       sbo = for_each_line(status_buf, ret + sbo,
-                               &check_stat_line);
-               }
-       }
-       slot_io(&wfds);
-       if (FD_ISSET(audiod_socket, &rfds)) {
-               ret = handle_connect();
-               if (ret < 0) {
-                       PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
-               }
+               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.event_handler = NULL;
+       ct->task.private_data = ct;
+       ct->fd = audiod_get_socket(); /* doesn't return on errors */
+       sprintf(ct->task.status, "command task");
+}
+
+static void status_event_handler(__a_unused struct task *t)
+{
+       struct timeval delay = {1, 0};
+       int i;
+       struct status_task *st = t->private_data;
+
+       PARA_ERROR_LOG("%s\n", PARA_STRERROR(-t->ret));
+       close_stat_pipe();
+       /* avoid busy loop if server is down */
+       tv_add(now, &delay, &st->restart_barrier);
+       FOR_EACH_AUDIO_FORMAT(i)
+               afi[i].restart_barrier = st->restart_barrier;
+}
+
+static void status_pre_select(struct sched *s, struct task *t)
+{
+       struct status_task *st = t->private_data;
+       t->ret = 1;
+       if (st->fd >= 0 && audiod_status == AUDIOD_OFF)
+               close_stat_pipe();
+       if (st->fd < 0 && audiod_status != AUDIOD_OFF
+               && tv_diff(now, &st->restart_barrier, NULL) > 0) {
+               st->fd = open_stat_pipe();
+               st->loaded = 0;
+               st->buf[0] = '\0';
        }
-       /* signals */
-       if (FD_ISSET(signal_pipe, &rfds)) {
-               int sig_nr = para_next_signal();
-               if (sig_nr > 0)
-                       handle_signal(sig_nr);
+       if (st->fd >= 0 && audiod_status != AUDIOD_OFF)
+               para_fd_set(st->fd, &s->rfds, &s->max_fileno);
+}
+
+static void status_post_select(struct sched *s, struct task *t)
+{
+       struct status_task *st = t->private_data;
+
+       t->ret = 1;
+       if (st->fd < 0 || !FD_ISSET(st->fd, &s->rfds))
+               return;
+       t->ret = read(st->fd, st->buf + st->loaded, STRINGSIZE - 1 - st->loaded);
+       if (t->ret <= 0) {
+               if (!t->ret)
+                       t->ret = -E_STATUS_EOF;
+               return;
        }
-       goto repeat;
+       st->buf[t->ret + st->loaded] = '\0';
+       st->loaded = for_each_line(st->buf, t->ret + st->loaded,
+               &check_stat_line);
+}
+
+static void init_status_task(struct status_task *st)
+{
+       memset(st, 0, sizeof(struct status_task));
+       st->task.pre_select = status_pre_select;
+       st->task.post_select = status_post_select;
+       st->task.event_handler = status_event_handler;
+       st->task.private_data = st;
+       st->fd = -1;
+       st->sa_time_diff_sign = 1;
+       sprintf(st->task.status, "status task");
 }
 
 static void set_initial_status(void)
@@ -1581,37 +1044,58 @@ static void set_initial_status(void)
                PARA_WARNING_LOG("%s", "invalid mode\n");
 }
 
-int __noreturn main(int argc, char *argv[])
+int main(int argc, char *argv[])
 {
        char *cf;
-       int i;
+       int ret, i;
+       struct sched s;
+       struct command_task command_task_struct, *cmd_task = &command_task_struct;
+       struct task audiod_task_struct, *audiod_task = &audiod_task_struct;
+
+       init_sched();
 
        valid_fd_012();
-       hostname = para_hostname();
        cmdline_parser(argc, argv, &conf);
-       para_drop_privileges(conf.user_arg);
+       para_drop_privileges(conf.user_arg, conf.group_arg);
        cf = configfile_exists();
        if (cf) {
                if (cmdline_parser_configfile(cf, &conf, 0, 0, 0)) {
-                       fprintf(stderr, "parse error in config file\n");
+                       PARA_EMERG_LOG("%s", "parse error in config file\n");
                        exit(EXIT_FAILURE);
                }
        }
+       if (conf.logfile_given)
+               logfile = open_log(conf.logfile_arg);
        log_welcome("para_audiod", conf.loglevel_arg);
        i = init_stream_io();
        if (i < 0) {
-               fprintf(stderr, "init stream io error: %s\n",
-                       PARA_STRERROR(-i));
+               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);
-       stat_item_ringbuf = ringbuffer_new(RINGBUFFER_SIZE);
        init_grabbing();
        setup_signal_handling();
+       signal_setup_default(sig_task);
+       sig_task->task.event_handler = signal_event_handler;
+
+       init_status_task(stat_task);
+       init_command_task(cmd_task);
+       init_audiod_task(audiod_task);
+
        if (conf.daemon_given)
                daemon_init();
-       audiod_mainloop();
+
+       register_task(&sig_task->task);
+       register_task(&cmd_task->task);
+       register_task(&stat_task->task);
+       register_task(audiod_task);
+       s.default_timeout.tv_sec = 3;
+       s.default_timeout.tv_usec = 99 * 1000;
+       ret = sched(&s);
+
+       PARA_EMERG_LOG("%s\n", PARA_STRERROR(-ret));
+       return EXIT_FAILURE;
 }