command_util: Generate properly documented command header files.
[paraslash.git] / server.c
index f6bc07d..2455626 100644 (file)
--- a/server.c
+++ b/server.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1997-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1997-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 /**
  * \mainpage Paraslash API Reference
  *
- * Starting points for getting an overview are
+ * Starting points for getting an overview:
  *
- * probably:
  *
  *     - The main programs: \ref server.c, \ref audiod.c, \ref client.c,
- *       \ref audioc.c, \ref fsck.c,
+ *       \ref audioc.c, \ref afh.c
  *     - Server: \ref server_command, \ref sender,
  *     - Audio file selector: \ref audio_format_handler, \ref mood, \ref afs_table,
  *     - Client: \ref receiver, \ref receiver_node, \ref filter, \ref filter_node.
  *
  * The gory details, listed by topic:
  *
- *     - Audio format handlers: \ref mp3_afh.c, \ref ogg_afh.c, \ref aac_afh.c,
- *     - Decoders: \ref mp3dec.c, \ref oggdec.c, \ref aacdec.c,
- *     - Volume normalizer: \ref compress.c,
+ *     - Audio format handlers: \ref send_common.c \ref mp3_afh.c, \ref ogg_afh.c, \ref aac_afh.c,
+ *     - Decoders: \ref mp3dec_filter.c, \ref oggdec_filter.c, \ref aacdec_filter.c,
+ *     - Volume normalizer: \ref compress_filter.c,
  *     - Output: \ref alsa_write.c, \ref osx_write.c,
  *     - http: \ref http_recv.c, \ref http_send.c,
- *     - ortp: \ref ortp_recv.c, \ref ortp_send.c,
+ *     - udp: \ref udp_recv.c, \ref udp_send.c,
  *     - dccp: \ref dccp_recv.c, \ref dccp_send.c,
  *     - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
  *     - Afs structures: \ref afs_table, \ref audio_file_data,
@@ -48,7 +47,6 @@
  *     - Time: \ref time.c,
  *     - Spawning processes: \ref exec.c,
  *     - Inter process communication: \ref ipc.c,
- *     - The object storage layer: \ref osl.c,
  *     - Blob tables: \ref blob.c,
  *     - The error subssystem: \ref error.h.
  *     - Access control for paraslash senders: \ref acl.c, \ref acl.h.
  * Low-level data structures:
  *
  *     - Doubly linked lists: \ref list.h,
- *     - Red-black trees: \ref rbtree.h, \ref rbtree.c,
  *     - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h,
  *     - Hashing: \ref hash.h, \ref sha1.h, \ref sha1.c,
  *     - Crypto: \ref crypt.c.
- *
+ *     - Forward error correction: \ref fec.c
  */
 
 #include <signal.h>
-#include <sys/types.h>
 #include <dirent.h>
+#include <sys/time.h>
+#include <openssl/rc4.h>
+#include <osl.h>
 
 #include "para.h"
 #include "error.h"
+#include "crypt.h"
 #include "server.cmdline.h"
 #include "afh.h"
 #include "string.h"
 #include "vss.h"
 #include "config.h"
 #include "close_on_fork.h"
+#include "list.h"
 #include "send.h"
 #include "net.h"
 #include "daemon.h"
 #include "ipc.h"
 #include "fd.h"
-#include "list.h"
 #include "sched.h"
 #include "signal.h"
 #include "user_list.h"
+#include "color.h"
 
-/** define the array of error lists needed by para_server */
+/** Define the array of error lists needed by para_server. */
 INIT_SERVER_ERRLISTS;
 
-/** shut down non-authorized connections after that many seconds */
+/** Shut down non-authorized connections after that many seconds. */
 #define ALARM_TIMEOUT 10
 
 /**
@@ -100,95 +101,77 @@ INIT_SERVER_ERRLISTS;
 struct misc_meta_data *mmd;
 
 /**
- * the configuration of para_server
+ * The configuration of para_server
  *
  * It also contains the options for the audio file selector, audio format
  * handler and all supported senders.
  */
 struct server_args_info conf;
 
-/** the file containing user information (public key, permissions) */
-char *user_list_file = NULL;
-
-extern void dccp_send_init(struct sender *);
-extern void http_send_init(struct sender *);
-extern void ortp_send_init(struct sender *);
-
-/** the list of supported senders */
-struct sender senders[] = {
-       {
-               .name = "http",
-               .init = http_send_init,
-       },
-       {
-               .name = "dccp",
-               .init = dccp_send_init,
-       },
-#ifdef HAVE_ORTP
-       {
-               .name = "ortp",
-               .init = ortp_send_init,
-       },
-#endif
-       {
-               .name = NULL,
-       }
-};
+/** A random value used in child context for authentication. */
+uint32_t afs_socket_cookie;
 
+/** The mutex protecting the shared memory area containing the mmd struct. */
+int mmd_mutex;
 
-/* global variables for server-internal use */
-static FILE *logfile;
-static int mmd_mutex, mmd_shm_id;
-static int signal_pipe;
+/** The file containing user information (public key, permissions). */
+static char *user_list_file = NULL;
 
-/**
- * para_server's log function
- *
- * \param ll the log level
- * \param fmt the format string describing the log message
- */
-void para_log(int ll, const char* fmt,...)
+
+/** The task responsible for server command handling. */
+struct server_command_task {
+       /** TCP port on which para_server listens for connections. */
+       int listen_fd;
+       /** Copied from para_server's main function. */
+       int argc;
+       /** Argument vector passed to para_server's main function. */
+       char **argv;
+       /** The command task structure for scheduling. */
+       struct task task;
+};
+
+static int want_colors(void)
 {
-       va_list argp;
-       FILE *outfd;
-       struct tm *tm;
-       time_t t1;
-       char str[MAXLINE] = "";
-       pid_t mypid;
-
-       if (ll < conf.loglevel_arg)
+       if (conf.color_arg == color_arg_no)
+               return 0;
+       if (conf.color_arg == color_arg_yes)
+               return 1;
+       if (conf.logfile_given)
+               return 0;
+       return isatty(STDERR_FILENO);
+}
+
+static void init_colors_or_die(void)
+{
+       int ret, i;
+
+       if (!want_colors())
                return;
-       outfd = logfile? logfile : stderr;
-       time(&t1);
-       tm = localtime(&t1);
-       strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
-       fprintf(outfd, "%s ", str);
-       if (conf.loglevel_arg <= INFO)
-               fprintf(outfd, "%i: ", ll);
-       mypid = getpid();
-       if (conf.loglevel_arg <= INFO)
-               fprintf(outfd, "(%d) ", (int)mypid);
-       va_start(argp, fmt);
-       vfprintf(outfd, fmt, argp);
-       va_end(argp);
+       daemon_set_flag(DF_COLOR_LOG);
+       daemon_set_default_log_colors();
+       for (i = 0; i < conf.log_color_given; i++) {
+               ret = daemon_set_log_color(conf.log_color_arg[i]);
+               if (ret < 0)
+                       exit(EXIT_FAILURE);
+       }
 }
 
 /*
  * setup shared memory area and get mutex for locking
  */
-static void shm_init(void)
+static void init_ipc_or_die(void)
 {
        void *shm;
-       int ret = shm_new(sizeof(struct misc_meta_data));
+       int shmid, ret = shm_new(sizeof(struct misc_meta_data));
 
        if (ret < 0)
                goto err_out;
-
-       ret = shm_attach(ret, ATTACH_RW, &shm);
+       shmid = ret;
+       ret = shm_attach(shmid, ATTACH_RW, &shm);
+       shm_destroy(shmid);
        if (ret < 0)
                goto err_out;
        mmd = shm;
-       mmd_shm_id = ret;
 
        ret = mutex_new();
        if (ret < 0)
@@ -202,41 +185,27 @@ static void shm_init(void)
        mmd->active_connections = 0;
        mmd->vss_status_flags = VSS_NEXT;
        mmd->new_vss_status_flags = VSS_NEXT;
-       mmd->sender_cmd_data.cmd_num = -1;
        return;
 err_out:
-       PARA_EMERG_LOG("%s", para_strerror(-ret));
+       PARA_EMERG_LOG("%s\n", para_strerror(-ret));
        exit(EXIT_FAILURE);
 }
 
 /**
- * lock the shared memory area containing the mmd struct
+ * (Re-)read the server configuration files.
  *
- * \sa semop(2), struct misc_meta_data.
- */
-void mmd_lock(void)
-{
-       mutex_lock(mmd_mutex);
-}
-
-/**
- * unlock the shared memory area containing the mmd struct
+ * \param override Passed to gengetopt to activate the override feature.
  *
- * \sa semop(2), struct misc_meta_data
+ * This function also re-opens the logfile and sets the global \a
+ * user_list_file variable.
  */
-
-void mmd_unlock(void)
-{
-       mutex_unlock(mmd_mutex);
-}
-
-static void parse_config(int override)
+void parse_config_or_die(int override)
 {
        char *home = para_homedir();
-       struct stat statbuf;
        int ret;
        char *cf;
 
+       daemon_close_log();
        if (conf.config_file_given)
                cf = para_strdup(conf.config_file_arg);
        else
@@ -246,31 +215,33 @@ static void parse_config(int override)
                user_list_file = make_message("%s/.paraslash/server.users", home);
        else
                user_list_file = para_strdup(conf.user_list_arg);
-       ret = stat(cf, &statbuf);
-       if (ret && conf.config_file_given) {
+       ret = file_exists(cf);
+       if (conf.config_file_given && !ret)  {
                ret = -1;
-               PARA_EMERG_LOG("can not stat config file %s\n", cf);
+               PARA_EMERG_LOG("can not read config file %s\n", cf);
                goto out;
        }
-       if (!ret) {
+       if (ret) {
                int tmp = conf.daemon_given;
                struct server_cmdline_parser_params params = {
                        .override = override,
                        .initialize = 0,
-                       .check_required = 0,
-                       .check_ambiguity = 0
+                       .check_required = 1,
+                       .check_ambiguity = 0,
+                       .print_errors = !conf.daemon_given
                };
                server_cmdline_parser_config_file(cf, &conf, &params);
                conf.daemon_given = tmp;
        }
-       /* logfile */
-       if (!conf.logfile_given && conf.daemon_given) {
-               ret = -1;
-               PARA_EMERG_LOG("%s", "daemon, but no log file\n");
-               goto out;
+       if (conf.logfile_given) {
+               daemon_set_logfile(conf.logfile_arg);
+               daemon_open_log_or_die();
        }
-       if (conf.logfile_given)
-               logfile = open_log(conf.logfile_arg);
+       daemon_set_loglevel(conf.loglevel_arg);
+       init_colors_or_die();
+       daemon_set_flag(DF_LOG_PID);
+       daemon_set_flag(DF_LOG_LL);
+       daemon_set_flag(DF_LOG_TIME);
        ret = 1;
 out:
        free(cf);
@@ -282,148 +253,272 @@ out:
        exit(EXIT_FAILURE);
 }
 
-static void setup_signal_handling(void)
+static void signal_pre_select(struct sched *s, struct task *t)
 {
-       signal_pipe = para_signal_init(); /* always successful */
+       struct signal_task *st = container_of(t, struct signal_task, task);
+       para_fd_set(st->fd, &s->rfds, &s->max_fileno);
+}
 
-       PARA_NOTICE_LOG("setting up signal handlers\n");
-       if (para_install_sighandler(SIGINT) < 0)
-               goto err;
-       if (para_install_sighandler(SIGTERM) < 0)
-               goto err;
-       if (para_install_sighandler(SIGHUP) < 0)
-               goto err;
-       if (para_install_sighandler(SIGCHLD) < 0)
-               goto err;
-       if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
-               goto err;
-       if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
-               goto err;
-       add_close_on_fork_list(signal_pipe);
-       return;
-err:
-       PARA_EMERG_LOG("could not install signal handlers\n");
-       exit(EXIT_FAILURE);
+/*
+ * called when server gets SIGHUP or when client invokes hup command.
+ */
+static void handle_sighup(void)
+{
+       PARA_NOTICE_LOG("SIGHUP\n");
+       parse_config_or_die(1); /* reopens log */
+       init_user_list(user_list_file); /* reload user list */
+       if (mmd->afs_pid)
+               kill(mmd->afs_pid, SIGHUP);
 }
 
-static unsigned init_network(void)
+static void signal_post_select(struct sched *s, struct task *t)
 {
-       int fd, ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
+       struct signal_task *st = container_of(t, struct signal_task, task);
 
-       if (ret < 0)
-               goto err;
-       fd = ret;
-       ret = mark_fd_nonblocking(fd);
-       if (ret < 0)
-               goto err;
-       add_close_on_fork_list(fd); /* child doesn't need the listener */
-       return fd;
-err:
-       PARA_EMERG_LOG("%s\n", para_strerror(-ret));
-       exit(EXIT_FAILURE);
+       if (!FD_ISSET(st->fd, &s->rfds))
+               return;
+
+       st->signum = para_next_signal();
+       switch (st->signum) {
+       case SIGHUP:
+               handle_sighup();
+               break;
+       case SIGCHLD:
+               for (;;) {
+                       pid_t pid;
+                       int ret = para_reap_child(&pid);
+                       if (ret <= 0)
+                               break;
+                       if (pid != mmd->afs_pid)
+                               continue;
+                       PARA_EMERG_LOG("fatal: afs died\n");
+                       kill(0, SIGTERM);
+                       goto cleanup;
+               }
+               break;
+       /* die on sigint/sigterm. Kill all children too. */
+       case SIGINT:
+       case SIGTERM:
+               PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
+               kill(0, SIGTERM);
+               /*
+                * We must wait for afs because afs catches SIGINT/SIGTERM.
+                * Before reacting to the signal, afs might want to use the
+                * shared memory area and the mmd mutex.  If we destroy this
+                * mutex too early and afs tries to lock the shared memory
+                * area, the call to mutex_lock() will fail and terminate the
+                * afs process. This leads to dirty osl tables.
+                *
+                * There's no such problem with the other children of the
+                * server process (the command handlers) as these reset their
+                * SIGINT/SIGTERM handlers to the default action, i.e.  these
+                * processes get killed immediately by the above kill().
+                */
+               PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
+                       (int)mmd->afs_pid);
+               waitpid(mmd->afs_pid, NULL, 0);
+cleanup:
+               free(mmd->afd.afhi.chunk_table);
+               close_listed_fds();
+               mutex_destroy(mmd_mutex);
+               shm_detach(mmd);
+               exit(EXIT_FAILURE);
+       }
 }
 
-static void init_random_seed(void)
+static void init_signal_task(void)
 {
-       int fd, ret = -1;
-       unsigned int seed;
-       size_t len = sizeof(unsigned int);
+       static struct signal_task signal_task_struct,
+               *st = &signal_task_struct;
+
+       st->task.pre_select = signal_pre_select;
+       st->task.post_select = signal_post_select;
+       sprintf(st->task.status, "signal task");
+
+       PARA_NOTICE_LOG("setting up signal handling\n");
+       st->fd = para_signal_init(); /* always successful */
+       para_install_sighandler(SIGINT);
+       para_install_sighandler(SIGTERM);
+       para_install_sighandler(SIGHUP);
+       para_install_sighandler(SIGCHLD);
+       para_sigaction(SIGPIPE, SIG_IGN);
+       add_close_on_fork_list(st->fd);
+       register_task(&st->task);
+}
 
-       fd = open("/dev/urandom", O_RDONLY);
-       if (fd < 0)
+static void command_pre_select(struct sched *s, struct task *t)
+{
+       struct server_command_task *sct = container_of(t, struct server_command_task, task);
+       para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
+}
+
+static void command_post_select(struct sched *s, struct task *t)
+{
+       struct server_command_task *sct = container_of(t, struct server_command_task, task);
+
+       int new_fd, ret, i;
+       char *peer_name;
+       pid_t child_pid;
+       uint32_t *chunk_table;
+
+       if (!FD_ISSET(sct->listen_fd, &s->rfds))
+               return;
+       ret = para_accept(sct->listen_fd, NULL, 0);
+       if (ret < 0)
                goto out;
-       ret = -2;
-       if (read(fd, &seed, len) != len)
+       new_fd = ret;
+       peer_name = remote_name(new_fd);
+       PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
+       mmd->num_connects++;
+       mmd->active_connections++;
+       /*
+        * The chunk table is a pointer located in the mmd struct that points
+        * to dynamically allocated memory, i.e. it must be freed by the parent
+        * and the child. However, as the mmd struct is in a shared memory
+        * area, there's no guarantee that after the fork this pointer is still
+        * valid in child context. As it is not used in the child anyway, we
+        * save it to a local variable before the fork and free the memory via
+        * that copy in the child directly after the fork.
+        */
+       chunk_table = mmd->afd.afhi.chunk_table;
+       child_pid = fork();
+       if (child_pid < 0) {
+               ret = -ERRNO_TO_PARA_ERROR(errno);
                goto out;
-       srandom(seed);
-       ret = 1;
-out:
-       if (fd >= 0)
-               close(fd);
-       if (ret > 0)
+       }
+       if (child_pid) {
+               close(new_fd);
+               /* parent keeps accepting connections */
                return;
-       PARA_EMERG_LOG("can not seed pseudo random generator (ret = %d)\n",
-               ret);
-       exit(EXIT_FAILURE);
+       }
+       /* mmd might already have changed at this point */
+       free(chunk_table);
+       alarm(ALARM_TIMEOUT);
+       close_listed_fds();
+       para_signal_shutdown();
+       /*
+        * put info on who we are serving into argv[0] to make
+        * client ip visible in top/ps
+        */
+       for (i = sct->argc - 1; i >= 0; i--)
+               memset(sct->argv[i], 0, strlen(sct->argv[i]));
+       sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
+       return handle_connect(new_fd, peer_name);
+out:
+       if (ret < 0)
+               PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 }
 
-uint32_t afs_socket_cookie;
-int afs_socket;
-static pid_t afs_pid;
+static void init_server_command_task(int argc, char **argv)
+{
+       int ret;
+       static struct server_command_task server_command_task_struct,
+               *sct = &server_command_task_struct;
+
+       PARA_NOTICE_LOG("initializing tcp command socket\n");
+       sct->task.pre_select = command_pre_select;
+       sct->task.post_select = command_post_select;
+       sct->argc = argc;
+       sct->argv = argv;
+       ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
+       if (ret < 0)
+               goto err;
+       sct->listen_fd = ret;
+       ret = mark_fd_nonblocking(sct->listen_fd);
+       if (ret < 0)
+               goto err;
+       add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
+       register_task(&sct->task);
+       return;
+err:
+       PARA_EMERG_LOG("%s\n", para_strerror(-ret));
+       exit(EXIT_FAILURE);
+}
 
-static void init_afs(void)
+static int init_afs(void)
 {
        int ret, afs_server_socket[2];
 
        ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
        if (ret < 0)
                exit(EXIT_FAILURE);
-       afs_socket_cookie = para_random((uint32_t)-1);
-       afs_pid = fork();
-       if (afs_pid < 0)
+       get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
+               sizeof(afs_socket_cookie));
+       mmd->afs_pid = fork();
+       if (mmd->afs_pid < 0)
                exit(EXIT_FAILURE);
-       if (!afs_pid) { /* child (afs) */
+       if (!mmd->afs_pid) { /* child (afs) */
                close(afs_server_socket[0]);
                afs_init(afs_socket_cookie, afs_server_socket[1]);
        }
        close(afs_server_socket[1]);
-       afs_socket = afs_server_socket[0];
-       ret = mark_fd_nonblocking(afs_socket);
+       ret = mark_fd_nonblocking(afs_server_socket[0]);
        if (ret < 0)
                exit(EXIT_FAILURE);
-       add_close_on_fork_list(afs_socket);
-       PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n", afs_socket,
-               (unsigned) afs_socket_cookie);
+       add_close_on_fork_list(afs_server_socket[0]);
+       PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
+               afs_server_socket[0], (unsigned) afs_socket_cookie);
+       return afs_server_socket[0];
 }
 
+__noreturn static void tmp_sigchld_handler(__a_unused int s)
+{
+       PARA_EMERG_LOG("caught early SIGCHLD\n");
+       exit(EXIT_FAILURE);
+}
 
-static unsigned server_init(int argc, char **argv)
+static void server_init(int argc, char **argv)
 {
-       /* connector's address information */
-       int sockfd;
+       struct server_cmdline_parser_params params = {
+               .override = 0,
+               .initialize = 1,
+               .check_required = 0,
+               .check_ambiguity = 0,
+               .print_errors = 1
+       };
+       int afs_socket;
 
-       init_random_seed();
+       valid_fd_012();
+       init_random_seed_or_die();
        /* parse command line options */
-       server_cmdline_parser(argc, argv, &conf);
+       server_cmdline_parser_ext(argc, argv, &conf, &params);
        HANDLE_VERSION_FLAG("server", conf);
-       para_drop_privileges(conf.user_arg, conf.group_arg);
+       drop_privileges_or_die(conf.user_arg, conf.group_arg);
        /* parse config file, open log and set defaults */
-       parse_config(0);
-       log_welcome("para_server", conf.loglevel_arg);
-       shm_init(); /* init mmd struct */
+       parse_config_or_die(0);
+       log_welcome("para_server");
+       init_ipc_or_die(); /* init mmd struct and mmd->lock */
+       /* make sure, the global now pointer is uptodate */
+       gettimeofday(now, NULL);
        server_uptime(UPTIME_SET); /* reset server uptime */
        init_user_list(user_list_file);
        /* become daemon */
        if (conf.daemon_given)
-               daemon_init();
+               daemonize();
        PARA_NOTICE_LOG("initializing audio format handlers\n");
        afh_init();
-       PARA_NOTICE_LOG("initializing virtual streaming system\n");
-       mmd->server_pid = getpid();
-       setup_signal_handling();
+
+       /*
+        * Although afs uses its own signal handling we must ignore SIGUSR1
+        * _before_ the afs child process gets born by init_afs() below.  It's
+        * racy to do this in the child because the parent might send SIGUSR1
+        * before the child gets a chance to ignore this signal -- only the
+        * good die young.
+        */
+       para_sigaction(SIGUSR1, SIG_IGN);
+       /*
+        * We have to install a SIGCHLD handler before the afs process is being
+        * forked off. Otherwise, para_server does not notice if afs dies before
+        * the SIGCHLD handler has been installed by init_signal_task() below.
+        */
+       para_sigaction(SIGCHLD, tmp_sigchld_handler);
        PARA_NOTICE_LOG("initializing the audio file selector\n");
-       init_afs();
-       vss_init();
-       mmd_lock();
-       /* init network socket */
-       PARA_NOTICE_LOG("initializing tcp command socket\n");
-       sockfd = init_network();
+       afs_socket = init_afs();
+       init_signal_task();
+       PARA_NOTICE_LOG("initializing virtual streaming system\n");
+       init_vss_task(afs_socket);
+       init_server_command_task(argc, argv);
        PARA_NOTICE_LOG("server init complete\n");
-       return sockfd;
-}
-
-/*
- * called when server gets SIGHUP or when client invokes hup command.
- */
-static void handle_sighup(void)
-{
-       PARA_NOTICE_LOG("%s", "SIGHUP\n");
-       close_log(logfile); /* gets reopened if necessary by parse_config */
-       logfile = NULL;
-       parse_config(1); /* reopens log */
-       init_user_list(user_list_file); /* reload user list */
-       if (afs_pid)
-               kill(afs_pid, SIGHUP);
 }
 
 static void status_refresh(void)
@@ -434,10 +529,12 @@ static void status_refresh(void)
        if (prev_events != mmd->events)
                goto out;
        if (mmd->new_vss_status_flags != mmd->vss_status_flags)
-               goto out;
+               goto out_inc_events;
        if (uptime / 60 != prev_uptime / 60)
-               goto out;
-       ret = 0;
+               goto out_inc_events;
+       return;
+out_inc_events:
+       mmd->events++;
 out:
        prev_uptime = uptime;
        prev_events = mmd->events;
@@ -449,124 +546,42 @@ out:
        }
 }
 
+static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
+               struct timeval *timeout_tv)
+{
+       int ret;
+
+       status_refresh();
+       mutex_unlock(mmd_mutex);
+       ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
+       mutex_lock(mmd_mutex);
+       return ret;
+}
+
 /**
- * the main function of para_server
+ * The main function of para_server.
  *
- * \param argc usual argument count
- * \param argv usual argument vector
- *
- * \return EXIT_SUCCESS or EXIT_FAILURE
+ * \param argc Usual argument count.
+ * \param argv Usual argument vector.
  *
+ * \return EXIT_SUCCESS or EXIT_FAILURE.
  */
 int main(int argc, char *argv[])
 {
-       /* listen on sock_fd, new connection on new_fd */
-       int sockfd, new_fd;
-       char *peer_name;
-       int i, max_fileno, ret;
-       pid_t chld_pid;
-       fd_set rfds, wfds;
-       struct timeval *timeout;
-
-       valid_fd_012();
-       sockfd = server_init(argc, argv);
-repeat:
-       FD_ZERO(&rfds);
-       FD_ZERO(&wfds);
-       max_fileno = -1;
-       /* check socket and signal pipe in any case */
-       para_fd_set(sockfd, &rfds, &max_fileno);
-       para_fd_set(signal_pipe, &rfds, &max_fileno);
-       timeout = vss_preselect(&rfds, &wfds, &max_fileno);
-       status_refresh();
-       for (i = 0; senders[i].name; i++) {
-               if (!senders[i].pre_select)
-                       continue;
-               senders[i].pre_select(&max_fileno, &rfds, &wfds);
-       }
-       mmd_unlock();
-       ret = para_select(max_fileno + 1, &rfds, &wfds, timeout);
-       mmd_lock();
-       vss_post_select(&rfds, &wfds);
-       if (ret < 0)
-               goto repeat;
-       for (i = 0; senders[i].name; i++) {
-               if (!senders[i].post_select)
-                       continue;
-               senders[i].post_select(&rfds, &wfds);
-       }
-       vss_send_chunk();
-       status_refresh();
-       if (FD_ISSET(signal_pipe, &rfds)) {
-               int sig;
-               pid_t pid;
-               sig = para_next_signal();
-               switch (sig) {
-               case SIGHUP:
-                       handle_sighup();
-                       break;
-               case SIGCHLD:
-                       for (;;) {
-                               ret = para_reap_child(&pid);
-                               if (ret <= 0)
-                                       break;
-                               if (pid != afs_pid)
-                                       continue;
-                               PARA_EMERG_LOG("fatal: afs died\n");
-                               goto genocide;
-                       }
-                       break;
-               /* die on sigint/sigterm. Kill all children too. */
-               case SIGINT:
-               case SIGTERM:
-                       PARA_EMERG_LOG("terminating on signal %d\n", sig);
-genocide:
-                       kill(0, SIGTERM);
-                       mutex_destroy(mmd_mutex);
-                       shm_detach(mmd);
-                       shm_destroy(mmd_shm_id);
-
-                       exit(EXIT_FAILURE);
-               }
-       }
-       if (mmd->sender_cmd_data.cmd_num >= 0) {
-               int num = mmd->sender_cmd_data.cmd_num,
-                       s = mmd->sender_cmd_data.sender_num;
-
-               if (senders[s].client_cmds[num])
-                       senders[s].client_cmds[num](&mmd->sender_cmd_data);
-               mmd->sender_cmd_data.cmd_num = -1;
-       }
-       if (!FD_ISSET(sockfd, &rfds))
-               goto repeat;
-
-       new_fd = para_accept(sockfd, NULL, 0);
-       if (new_fd < 0)
-               goto repeat;
-       peer_name = remote_name(new_fd);
-       PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
-       mmd->num_connects++;
-       mmd->active_connections++;
-       random();
-       chld_pid = fork();
-       if (chld_pid < 0) {
-               PARA_CRIT_LOG("%s", "fork failed\n");
-               goto repeat;
-       }
-       if (chld_pid) {
-               close(new_fd);
-               /* parent keeps accepting connections */
-               goto repeat;
+       int ret;
+       static struct sched s = {
+               .default_timeout = {
+                       .tv_sec = 1,
+                       .tv_usec = 0
+               },
+               .select_function = server_select
+       };
+       server_init(argc, argv);
+       mutex_lock(mmd_mutex);
+       ret = schedule(&s);
+       if (ret < 0) {
+               PARA_EMERG_LOG("%s\n", para_strerror(-ret));
+               exit(EXIT_FAILURE);
        }
-       alarm(ALARM_TIMEOUT);
-       close_listed_fds();
-       para_signal_shutdown();
-       /*
-        * put info on who we are serving into argv[0] to make
-        * client ip visible in top/ps
-        */
-       for (i = argc - 1; i >= 0; i--)
-               memset(argv[i], 0, strlen(argv[i]));
-       sprintf(argv[0], "para_server (serving %s)", peer_name);
-       return handle_connect(new_fd, peer_name);
+       exit(EXIT_SUCCESS);
 }