]> code.citadel.org Git - citadel.git/blobdiff - citadel/sysdep.c
* Added support for protocols over Unix domain sockets.
[citadel.git] / citadel / sysdep.c
index e160e361776d16f0ab3056bf009765a92b616214..59de2f8b5ab682cd8b091a26539ab1c3dfb76933 100644 (file)
@@ -6,8 +6,6 @@
  *
  * Here's where we (hopefully) have all the parts of the Citadel server that
  * would need to be altered to run the server in a non-POSIX environment.
- * Wherever possible, we use function wrappers and type definitions to create
- * abstractions that are platform-independent from the calling side.
  * 
  * Eventually we'll try porting to a different platform and either have
  * multiple variants of this file or simply load it up with #ifdefs.
@@ -28,6 +26,7 @@
 #include <limits.h>
 #include <netinet/in.h>
 #include <netdb.h>
+#include <sys/un.h>
 #include <string.h>
 #include <pwd.h>
 #include <errno.h>
@@ -66,11 +65,19 @@ struct TheHeap *heap = NULL;
 pthread_mutex_t Critters[MAX_SEMAPHORES];      /* Things needing locking */
 pthread_key_t MyConKey;                                /* TSD key for MyContext() */
 
-int msock;                                     /* master listening socket */
 int verbosity = DEFAULT_VERBOSITY;             /* Logging level */
 
 struct CitContext masterCC;
 int rescan[2];                                 /* The Rescan Pipe */
+time_t last_purge = 0;                         /* Last dead session purge */
+int num_threads = 0;                           /* Current number of threads */
+int num_sessions = 0;                          /* Current number of sessions */
+
+fd_set masterfds;                              /* Master sockets etc. */
+int masterhighest;
+
+time_t last_timer = 0L;                                /* Last timer hook processing */
+
 
 /*
  * lprintf()  ...   Write logging information
@@ -189,7 +196,7 @@ static volatile int time_to_die = 0;
 
 static RETSIGTYPE signal_cleanup(int signum) {
        time_to_die = 1;
-       }
+}
 
 
 /*
@@ -201,7 +208,7 @@ void init_sysdep(void) {
        /* Set up a bunch of semaphores to be used for critical sections */
        for (a=0; a<MAX_SEMAPHORES; ++a) {
                pthread_mutex_init(&Critters[a], NULL);
-               }
+       }
 
        /*
         * Set up a place to put thread-specific data.
@@ -210,7 +217,7 @@ void init_sysdep(void) {
         */
        if (pthread_key_create(&MyConKey, NULL) != 0) {
                lprintf(1, "Can't create TSD key!!  %s\n", strerror(errno));
-               }
+       }
 
        /*
         * The action for unexpected signals and exceptions should be to
@@ -227,7 +234,7 @@ void init_sysdep(void) {
         * socket breaks.
         */
        signal(SIGPIPE, SIG_IGN);
-       }
+}
 
 
 /*
@@ -235,6 +242,7 @@ void init_sysdep(void) {
  */
 void begin_critical_section(int which_one)
 {
+       /* lprintf(9, "begin_critical_section(%d)\n", which_one); */
        pthread_mutex_lock(&Critters[which_one]);
 }
 
@@ -243,6 +251,7 @@ void begin_critical_section(int which_one)
  */
 void end_critical_section(int which_one)
 {
+       /* lprintf(9, "end_critical_section(%d)\n", which_one); */
        pthread_mutex_unlock(&Critters[which_one]);
 }
 
@@ -251,47 +260,74 @@ void end_critical_section(int which_one)
 /*
  * This is a generic function to set up a master socket for listening on
  * a TCP port.  The server shuts down if the bind fails.
+ *
+ * If a negative number is specified, a Unix domain socket is created.
  */
 int ig_tcp_server(int port_number, int queue_len)
 {
        struct sockaddr_in sin;
+       struct sockaddr_un addr;
        int s, i;
+       int is_unix = 0;
 
-       memset(&sin, 0, sizeof(sin));
-       sin.sin_family = AF_INET;
-       sin.sin_addr.s_addr = INADDR_ANY;
+       if (port_number < 0) {
+               is_unix = 1;
+       }
 
-       if (port_number == 0) {
-               lprintf(1,
-                       "citserver: No port number specified.  Run setup.\n");
-               exit(1);
-               }
-       
-       sin.sin_port = htons((u_short)port_number);
+       if (is_unix) {
+               memset(&addr, 0, sizeof(addr));
+               addr.sun_family = AF_UNIX;
+               sprintf(addr.sun_path, USOCKPATH, 0-port_number);
+       }
+       else {
+               memset(&sin, 0, sizeof(sin));
+               sin.sin_family = AF_INET;
+               sin.sin_addr.s_addr = INADDR_ANY;
+               sin.sin_port = htons((u_short)port_number);
+       }
+
+       if (is_unix) {
+               s = socket(AF_UNIX, SOCK_STREAM, 0);
+       }
+       else {
+               s = socket(PF_INET, SOCK_STREAM,
+                       (getprotobyname("tcp")->p_proto));
+       }
 
-       s = socket(PF_INET, SOCK_STREAM, (getprotobyname("tcp")->p_proto));
        if (s < 0) {
                lprintf(1, "citserver: Can't create a socket: %s\n",
                        strerror(errno));
-               exit(errno);
-               }
+               return(-1);
+       }
 
        /* Set the SO_REUSEADDR socket option, because it makes sense. */
-       i = 1;
-       setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
+       if (!is_unix) {
+               i = 1;
+               setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
+       }
 
-       if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
-               lprintf(1, "citserver: Can't bind: %s\n", strerror(errno));
-               exit(errno);
+       if (is_unix) {
+               if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+                       lprintf(1, "citserver: Can't bind: %s\n",
+                               strerror(errno));
+                       return(-1);
                }
+       }
+       else {
+               if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
+                       lprintf(1, "citserver: Can't bind: %s\n",
+                               strerror(errno));
+                       return(-1);
+               }
+       }
 
        if (listen(s, queue_len) < 0) {
                lprintf(1, "citserver: Can't listen: %s\n", strerror(errno));
-               exit(errno);
-               }
+               return(-1);
+       }
 
        return(s);
-       }
+}
 
 
 
@@ -305,7 +341,7 @@ struct CitContext *MyContext(void) {
        retCC = (struct CitContext *) pthread_getspecific(MyConKey);
        if (retCC == NULL) retCC = &masterCC;
        return(retCC);
-       }
+}
 
 
 /*
@@ -314,12 +350,13 @@ struct CitContext *MyContext(void) {
 struct CitContext *CreateNewContext(void) {
        struct CitContext *me, *ptr;
        int num = 1;
+       int startover = 0;
 
        me = (struct CitContext *) mallok(sizeof(struct CitContext));
        if (me == NULL) {
                lprintf(1, "citserver: can't allocate memory!!\n");
                return NULL;
-               }
+       }
        memset(me, 0, sizeof(struct CitContext));
 
        /* The new context will be created already in the CON_EXECUTING state
@@ -331,39 +368,25 @@ struct CitContext *CreateNewContext(void) {
        begin_critical_section(S_SESSION_TABLE);
 
        /* obtain a unique session number */
-       for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
-               if (ptr->cs_pid == num) {
-                       ++num;
-                       ptr = ContextList;
+       do {
+               startover = 0;
+               for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
+                       if (ptr->cs_pid == num) {
+                               ++num;
+                               startover = 1;
+                       }
                }
-       }
+       } while (startover == 1);
 
        me->cs_pid = num;
        me->next = ContextList;
        ContextList = me;
+       ++num_sessions;
 
        end_critical_section(S_SESSION_TABLE);
        return(me);
-       }
-
-
-
-/*
- * Return the number of sessions currently running.
- * (This should probably be moved out of sysdep.c)
- */
-int session_count(void) {
-       struct CitContext *ptr;
-       int TheCount = 0;
-
-       begin_critical_section(S_SESSION_TABLE);
-       for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
-               ++TheCount;
-               }
-       end_critical_section(S_SESSION_TABLE);
+}
 
-       return(TheCount);
-       }
 
 
 /*
@@ -373,18 +396,32 @@ void client_write(char *buf, int nbytes)
 {
        int bytes_written = 0;
        int retval;
+       int sock;
+
+       if (CC->redirect_fp != NULL) {
+               fwrite(buf, nbytes, 1, CC->redirect_fp);
+               return;
+       }
+
+       if (CC->redirect_sock > 0) {
+               sock = CC->redirect_sock;       /* and continue below... */
+       }
+       else {
+               sock = CC->client_socket;
+       }
+
        while (bytes_written < nbytes) {
-               retval = write(CC->client_socket, &buf[bytes_written],
+               retval = write(sock, &buf[bytes_written],
                        nbytes - bytes_written);
                if (retval < 1) {
                        lprintf(2, "client_write() failed: %s\n",
                                strerror(errno));
-                       CC->kill_me = 1;
+                       if (sock == CC->client_socket) CC->kill_me = 1;
                        return;
-                       }
-               bytes_written = bytes_written + retval;
                }
+               bytes_written = bytes_written + retval;
        }
+}
 
 
 /*
@@ -401,7 +438,7 @@ void cprintf(const char *format, ...) {
                buf[sizeof buf - 2] = '\n';
        client_write(buf, strlen(buf)); 
        va_end(arg_ptr);
-       }   
+}   
 
 
 /*
@@ -409,7 +446,8 @@ void cprintf(const char *format, ...) {
  * Return values are:
  *     1       Requested number of bytes has been read.
  *     0       Request timed out.
- * If the socket breaks, the session is immediately terminated.
+ *     -1      The socket is broken.
+ * If the socket breaks, the session will be terminated.
  */
 int client_read_to(char *buf, int bytes, int timeout)
 {
@@ -422,7 +460,7 @@ int client_read_to(char *buf, int bytes, int timeout)
        while(len<bytes) {
                FD_ZERO(&rfds);
                FD_SET(CC->client_socket, &rfds);
-               tv.tv_sec = 1;
+               tv.tv_sec = timeout;
                tv.tv_usec = 0;
 
                retval = select( (CC->client_socket)+1, 
@@ -430,7 +468,7 @@ int client_read_to(char *buf, int bytes, int timeout)
 
                if (FD_ISSET(CC->client_socket, &rfds) == 0) {
                        return(0);
-                       }
+               }
 
                rlen = read(CC->client_socket, &buf[len], bytes-len);
                if (rlen<1) {
@@ -438,11 +476,11 @@ int client_read_to(char *buf, int bytes, int timeout)
                                strerror(errno));
                        CC->kill_me = 1;
                        return(-1);
-                       }
-               len = len + rlen;
                }
-       return(1);
+               len = len + rlen;
        }
+       return(1);
+}
 
 /*
  * Read data from the client socket with default timeout.
@@ -452,7 +490,7 @@ int client_read_to(char *buf, int bytes, int timeout)
 int client_read(char *buf, int bytes)
 {
        return(client_read_to(buf, bytes, config.c_sleeping));
-       }
+}
 
 
 /*
@@ -470,7 +508,7 @@ int client_gets(char *buf)
                retval = client_read(&buf[i], 1);
                if (retval != 1 || buf[i] == '\n' || i == 255)
                        break;
-               }
+       }
 
        /* If we got a long line, discard characters until the newline.
         */
@@ -484,7 +522,7 @@ int client_gets(char *buf)
        while ((strlen(buf)>0)&&(!isprint(buf[strlen(buf)-1])))
                buf[strlen(buf)-1] = 0;
        return(retval);
-       }
+}
 
 
 
@@ -492,9 +530,26 @@ int client_gets(char *buf)
  * The system-dependent part of master_cleanup() - close the master socket.
  */
 void sysdep_master_cleanup(void) {
-       lprintf(7, "Closing master socket %d\n", msock);
-       close(msock);
+       struct ServiceFunctionHook *serviceptr;
+       char sockpath[256];
+
+       /*
+        * close all protocol master sockets
+        */
+       for (serviceptr = ServiceHookTable; serviceptr != NULL;
+           serviceptr = serviceptr->next ) {
+               lprintf(3, "Closing listener on port %d\n",
+                       serviceptr->tcp_port);
+               close(serviceptr->msock);
+
+               /* If it's a Unix domain socket, remove the file. */
+               if (serviceptr->tcp_port < 0) {
+                       sprintf(sockpath, USOCKPATH, 0-(serviceptr->tcp_port));
+                       lprintf(9, "Removing <%s>\n", sockpath);
+                       unlink(sockpath);
+               }
        }
+}
 
 
 /*
@@ -525,12 +580,12 @@ void start_daemon(int do_close_stdio) {
                /* close(0); */
                close(1);
                close(2);
-               }
+       }
        signal(SIGHUP,SIG_IGN);
        signal(SIGINT,SIG_IGN);
        signal(SIGQUIT,SIG_IGN);
        if (fork()!=0) exit(0);
-       }
+}
 
 
 
@@ -552,7 +607,7 @@ void cmd_nset(char *cmdbuf)
                cprintf("%d Higher access required.\n", 
                        ERROR + HIGHER_ACCESS_REQUIRED);
                return;
-               }
+       }
 
        for (a=1; a<=3; ++a) {
                if (num_parms(cmdbuf) >= a) {
@@ -560,13 +615,13 @@ void cmd_nset(char *cmdbuf)
                        for (b=0; b<strlen(netsetup_args[a-1]); ++b) {
                                if (netsetup_args[a-1][b] == 34) {
                                        netsetup_args[a-1][b] = '_';
-                                       }
                                }
                        }
+               }
                else {
                        netsetup_args[a-1][0] = 0;
-                       }
                }
+       }
 
        sprintf(fbuf, "./netsetup \"%s\" \"%s\" \"%s\" </dev/null 2>&1",
                netsetup_args[0], netsetup_args[1], netsetup_args[2]);
@@ -574,30 +629,30 @@ void cmd_nset(char *cmdbuf)
        if (netsetup == NULL) {
                cprintf("%d %s\n", ERROR, strerror(errno));
                return;
-               }
+       }
 
        fbuf[0] = 0;
        while (ch = getc(netsetup), (ch > 0)) {
                fbuf[strlen(fbuf)+1] = 0;
                fbuf[strlen(fbuf)] = ch;
-               }
+       }
 
        retcode = pclose(netsetup);
 
        if (retcode != 0) {
                for (a=0; a<strlen(fbuf); ++a) {
                        if (fbuf[a] < 32) fbuf[a] = 32;
-                       }
+               }
                fbuf[245] = 0;
                cprintf("%d %s\n", ERROR, fbuf);
                return;
-               }
+       }
 
        cprintf("%d Command succeeded.  Output follows:\n", LISTING_FOLLOWS);
        cprintf("%s", fbuf);
        if (fbuf[strlen(fbuf)-1] != 10) cprintf("\n");
        cprintf("000\n");
-       }
+}
 
 
 
@@ -612,15 +667,15 @@ int convert_login(char NameToConvert[]) {
        pw = getpwnam(NameToConvert);
        if (pw == NULL) {
                return(0);
-               }
+       }
        else {
                strcpy(NameToConvert, pw->pw_gecos);
                for (a=0; a<strlen(NameToConvert); ++a) {
                        if (NameToConvert[a] == ',') NameToConvert[a] = 0;
-                       }
-               return(1);
                }
+               return(1);
        }
+}
 
 
 
@@ -629,19 +684,24 @@ int convert_login(char NameToConvert[]) {
  * This function has code to prevent it from running more than once every
  * few seconds, because running it after every single unbind would waste a lot
  * of CPU time and keep the context list locked too much.
+ *
+ * After that's done, we raise or lower the size of the worker thread pool
+ * if such an action is appropriate.
  */
 void dead_session_purge(void) {
-       static time_t last_purge = 0;
        struct CitContext *ptr, *rem;
-       
+        pthread_attr_t attr;
+       pthread_t newthread;
+
        if ( (time(NULL) - last_purge) < 5 ) return;    /* Too soon, go away */
+       time(&last_purge);
 
        do {
                rem = NULL;
                begin_critical_section(S_SESSION_TABLE);
                for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
                        if ( (ptr->state == CON_IDLE) && (ptr->kill_me) ) {
-                               rem = ptr;      
+                               rem = ptr;
                        }
                }
                end_critical_section(S_SESSION_TABLE);
@@ -649,13 +709,69 @@ void dead_session_purge(void) {
                /* RemoveContext() enters its own S_SESSION_TABLE critical
                 * section, so we have to do it like this.
                 */     
-               if (rem != NULL) RemoveContext(rem);
+               if (rem != NULL) {
+                       lprintf(9, "Purging session %d\n", rem->cs_pid);
+                       RemoveContext(rem);
+               }
 
        } while (rem != NULL);
-}
 
 
+       /* Raise or lower the size of the worker thread pool if such
+        * an action is appropriate.
+        */
+
+       if ( (num_sessions > num_threads)
+          && (num_threads < config.c_max_workers) ) {
+
+               pthread_attr_init(&attr);
+                       pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+               if (pthread_create(&newthread, &attr,
+                  (void* (*)(void*)) worker_thread, NULL) != 0) {
+                       lprintf(1, "Can't create worker thead: %s\n",
+                       strerror(errno));
+               }
+
+       }
        
+       else if ( (num_sessions < num_threads)
+          && (num_threads > config.c_min_workers) ) {
+               --num_threads;
+               pthread_exit(NULL);
+       }
+
+}
+
+
+
+
+
+/*
+ * Redirect a session's output to a file or socket.
+ * This function may be called with a file handle *or* a socket (but not
+ * both).  Call with neither to return output to its normal client socket.
+ */
+void CtdlRedirectOutput(FILE *fp, int sock) {
+
+       if (fp != NULL) CC->redirect_fp = fp;
+       else CC->redirect_fp = NULL;
+
+       if (sock > 0) CC->redirect_sock = sock;
+       else CC->redirect_sock = (-1);
+
+}
+
+
+/*
+ * masterCC is the context we use when not attached to a session.  This
+ * function initializes it.
+ */
+void InitializeMasterCC(void) {
+       memset(&masterCC, 0, sizeof(struct CitContext));
+       masterCC.internal_pgm = 1;
+}
+
+
 
 /*
  * Here's where it all begins.
@@ -669,10 +785,14 @@ int main(int argc, char **argv)
        struct passwd *pw;
        int drop_root_perms = 1;
        char *moddir;
+       struct ServiceFunctionHook *serviceptr;
         
        /* specify default port name and trace file */
        strcpy(tracefile, "");
 
+       /* initialize the master context */
+       InitializeMasterCC();
+
        /* parse command-line arguments */
        for (a=1; a<argc; ++a) {
 
@@ -683,27 +803,27 @@ int main(int argc, char **argv)
                        freopen(tracefile, "r", stdin);
                        freopen(tracefile, "w", stdout);
                        freopen(tracefile, "w", stderr);
-                       }
+               }
 
                /* run in the background if -d was specified */
                else if (!strcmp(argv[a], "-d")) {
                        start_daemon( (strlen(tracefile) > 0) ? 0 : 1 ) ;
-                       }
+               }
 
                /* -x specifies the desired logging level */
                else if (!strncmp(argv[a], "-x", 2)) {
                        verbosity = atoi(&argv[a][2]);
-                       }
+               }
 
                else if (!strncmp(argv[a], "-h", 2)) {
                        safestrncpy(bbs_home_directory, &argv[a][2],
                                    sizeof bbs_home_directory);
                        home_specified = 1;
-                       }
+               }
 
                else if (!strncmp(argv[a], "-f", 2)) {
                        do_defrag = 1;
-                       }
+               }
 
                /* -r tells the server not to drop root permissions. don't use
                 * this unless you know what you're doing. this should be
@@ -717,10 +837,10 @@ int main(int argc, char **argv)
                                        "citserver [-tTraceFile] [-d] [-f]"
                                        " [-xLogLevel] [-hHomeDir]\n");
                        exit(1);
-                       }
-
                }
 
+       }
+
        /* Tell 'em who's in da house */
        lprintf(1,
 "\nMultithreaded message server for Citadel/UX\n"
@@ -739,16 +859,64 @@ int main(int argc, char **argv)
        get_config();
 
        /*
-        * Bind the server to our favourite port.
-        * There is no need to check for errors, because ig_tcp_server()
-        * exits if it doesn't succeed.
+        * Do non system dependent startup functions.
         */
-       lprintf(7, "Attempting to bind to port %d...\n", config.c_port_number);
-       msock = ig_tcp_server(config.c_port_number, 5);
-       lprintf(7, "Listening on socket %d\n", msock);
+       master_startup();
+
+       /*
+        * Bind the server to our favorite ports.
+        */
+       CtdlRegisterServiceHook(config.c_port_number,           /* TCP */
+                               citproto_begin_session,
+                               do_command_loop);
+       CtdlRegisterServiceHook(0-config.c_port_number,         /* Unix */
+                               citproto_begin_session,
+                               do_command_loop);
 
        /*
-        * Now that we've bound the socket, change to the BBS user id and its
+        * Load any server-side modules (plugins) available here.
+        */
+       lprintf(7, "Initializing loadable modules\n");
+       if ((moddir = malloc(strlen(bbs_home_directory) + 9)) != NULL) {
+               sprintf(moddir, "%s/modules", bbs_home_directory);
+               DLoader_Init(moddir);
+               free(moddir);
+       }
+
+       /*
+        * The rescan pipe exists so that worker threads can be woken up and
+        * told to re-scan the context list for fd's to listen on.  This is
+        * necessary, for example, when a context is about to go idle and needs
+        * to get back on that list.
+        */
+       if (pipe(rescan)) {
+               lprintf(1, "Can't create rescan pipe!\n");
+               exit(errno);
+       }
+
+       /*
+        * Set up a fd_set containing all the master sockets to which we
+        * always listen.  It's computationally less expensive to just copy
+        * this to a local fd_set when starting a new select() and then add
+        * the client sockets than it is to initialize a new one and then
+        * figure out what to put there.
+        */
+       FD_ZERO(&masterfds);
+       masterhighest = 0;
+       FD_SET(rescan[0], &masterfds);
+       if (rescan[0] > masterhighest) masterhighest = rescan[0];
+
+       for (serviceptr = ServiceHookTable; serviceptr != NULL;
+           serviceptr = serviceptr->next ) {
+               FD_SET(serviceptr->msock, &masterfds);
+               if (serviceptr->msock > masterhighest) {
+                       masterhighest = serviceptr->msock;
+               }
+       }
+
+
+       /*
+        * Now that we've bound the sockets, change to the BBS user id and its
         * corresponding group ids
         */
        if (drop_root_perms) {
@@ -761,28 +929,16 @@ int main(int argc, char **argv)
                        if (setgid(pw->pw_gid))
                                lprintf(3, "setgid(%d): %s\n", pw->pw_gid,
                                        strerror(errno));
-                       }
+               }
                lprintf(7, "Changing uid to %d\n", BBSUID);
                if (setuid(BBSUID) != 0) {
                        lprintf(3, "setuid() failed: %s\n", strerror(errno));
-                       }
                }
+       }
 
        /*
-        * Do non system dependent startup functions.
-        */
-       master_startup();
-
-       /*
-        * Load any server-side modules (plugins) available here.
+        * Create the housekeeper thread
         */
-       lprintf(7, "Initializing loadable modules\n");
-       if ((moddir = malloc(strlen(bbs_home_directory) + 9)) != NULL) {
-               sprintf(moddir, "%s/modules", bbs_home_directory);
-               DLoader_Init(moddir);
-               free(moddir);
-               }
-
        lprintf(7, "Starting housekeeper thread\n");
        pthread_attr_init(&attr);
                pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
@@ -793,21 +949,10 @@ int main(int argc, char **argv)
        }
 
 
-       /*
-        * The rescan pipe exists so that worker threads can be woken up and
-        * told to re-scan the context list for fd's to listen on.  This is
-        * necessary, for example, when a context is about to go idle and needs
-        * to get back on that list.
-        */
-       if (pipe(rescan)) {
-               lprintf(1, "Can't create rescan pipe!\n");
-               exit(errno);
-       }
-
        /*
         * Now create a bunch of worker threads.
         */
-       for (i=0; i<(NUM_WORKER_THREADS-1); ++i) {
+       for (i=0; i<(config.c_min_workers-1); ++i) {
                pthread_attr_init(&attr);
                        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
                if (pthread_create(&HousekeepingThread, &attr,
@@ -824,8 +969,12 @@ int main(int argc, char **argv)
 }
 
 
-
-
+/*
+ * Bind a thread to a context.
+ */
+inline void become_session(struct CitContext *which_con) {
+       pthread_setspecific(MyConKey, (void *)which_con );
+}
 
 
 
@@ -835,21 +984,24 @@ int main(int argc, char **argv)
 void worker_thread(void) {
        int i;
        char junk;
-       int numselect = 0;
        int highest;
        struct CitContext *ptr;
        struct CitContext *bind_me = NULL;
        fd_set readfds;
        int retval;
        struct CitContext *con= NULL;   /* Temporary context pointer */
+       struct ServiceFunctionHook *serviceptr;
        struct sockaddr_in fsin;        /* Data for master socket */
        int alen;                       /* Data for master socket */
        int ssock;                      /* Descriptor for client socket */
+       struct timeval tv;
+
+       ++num_threads;
 
        while (!time_to_die) {
 
                /* 
-                * In a stupid environment, we would have all idle threads
+                * A naive implementation would have all idle threads
                 * calling select() and then they'd all wake up at once.  We
                 * solve this problem by putting the select() in a critical
                 * section, so only one thread has the opportunity to wake
@@ -859,68 +1011,73 @@ void worker_thread(void) {
                 */
 
                begin_critical_section(S_I_WANNA_SELECT);
-SETUP_FD:      FD_ZERO(&readfds);
-               FD_SET(msock, &readfds);
-               highest = msock;
-               FD_SET(rescan[0], &readfds);
-               if (rescan[0] > highest) highest = rescan[0];
-               numselect = 2;
-
+SETUP_FD:      memcpy(&readfds, &masterfds, sizeof(fd_set) );
+               highest = masterhighest;
                begin_critical_section(S_SESSION_TABLE);
                for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
                        if (ptr->state == CON_IDLE) {
                                FD_SET(ptr->client_socket, &readfds);
                                if (ptr->client_socket > highest)
                                        highest = ptr->client_socket;
-                               ++numselect;
                        }
                }
                end_critical_section(S_SESSION_TABLE);
 
-               retval = select(highest + 1, &readfds, NULL, NULL, NULL);
+               tv.tv_sec = 60;         /* wake up every minute if no input */
+               tv.tv_usec = 0;
+               retval = select(highest + 1, &readfds, NULL, NULL, &tv);
 
                /* Now figure out who made this select() unblock.
                 * First, check for an error or exit condition.
                 */
                if (retval < 0) {
                        end_critical_section(S_I_WANNA_SELECT);
-                       lprintf(9, "Exiting (%s)\n", errno);
+                       lprintf(9, "Exiting (%s)\n", strerror(errno));
                        time_to_die = 1;
                }
 
                /* Next, check to see if it's a new client connecting
                 * on the master socket.
                 */
-               else if (FD_ISSET(msock, &readfds)) {
-                       alen = sizeof fsin;
-                       ssock = accept(msock, (struct sockaddr *)&fsin, &alen);
-                       if (ssock < 0) {
-                               lprintf(2, "citserver: accept() failed: %s\n",
-                                       strerror(errno));
-                       }
-                       else {
-                               lprintf(7, "citserver: New client socket %d\n",
-                                       ssock);
-
-                               /* New context will be created already set up
-                                * in the CON_EXECUTING state.
-                                */
-                               con = CreateNewContext();
-
-                               /* Assign our new socket number to it. */
-                               con->client_socket = ssock;
+               else for (serviceptr = ServiceHookTable; serviceptr != NULL;
+                    serviceptr = serviceptr->next ) {
+
+                       if (FD_ISSET(serviceptr->msock, &readfds)) {
+                               alen = sizeof fsin;
+                               ssock = accept(serviceptr->msock,
+                                       (struct sockaddr *)&fsin, &alen);
+                               if (ssock < 0) {
+                                       lprintf(2, "citserver: accept(): %s\n",
+                                               strerror(errno));
+                               }
+                               else {
+                                       lprintf(7, "citserver: "
+                                               "New client socket %d\n",
+                                               ssock);
+
+                                       /* New context will be created already
+                                       * set up in the CON_EXECUTING state.
+                                       */
+                                       con = CreateNewContext();
+
+                                       /* Assign new socket number to it. */
+                                       con->client_socket = ssock;
+                                       con->h_command_function =
+                                               serviceptr->h_command_function;
        
-                               /* Set the SO_REUSEADDR socket option */
-                               i = 1;
-                               setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR,
-                                       &i, sizeof(i));
-
-                               pthread_setspecific(MyConKey, (void *)con);
-                               begin_session(con);
-                               /* do_command_loop(); */
-                               pthread_setspecific(MyConKey, (void *)NULL);
-                               con->state = CON_IDLE;
-                               goto SETUP_FD;
+                                       /* Set the SO_REUSEADDR socket option */
+                                       i = 1;
+                                       setsockopt(ssock, SOL_SOCKET,
+                                               SO_REUSEADDR,
+                                               &i, sizeof(i));
+
+                                       become_session(con);
+                                       begin_session(con);
+                                       serviceptr->h_greeting_function();
+                                       become_session(NULL);
+                                       con->state = CON_IDLE;
+                                       goto SETUP_FD;
+                               }
                        }
                }
 
@@ -928,7 +1085,7 @@ SETUP_FD:  FD_ZERO(&readfds);
                 * thread that the &readfds needs to be refreshed with more
                 * current data.
                 */
-               else if (FD_ISSET(rescan[0], &readfds)) {
+               if (!time_to_die) if (FD_ISSET(rescan[0], &readfds)) {
                        read(rescan[0], &junk, 1);
                        goto SETUP_FD;
                }
@@ -959,24 +1116,27 @@ SETUP_FD:        FD_ZERO(&readfds);
 
                        /* We're bound to a session, now do *one* command */
                        if (bind_me != NULL) {
-                               pthread_setspecific(MyConKey, (void *)bind_me);
-                               do_command_loop();
-                               pthread_setspecific(MyConKey, (void *)NULL);
+                               become_session(bind_me);
+                               CC->h_command_function();
+                               become_session(NULL);
                                bind_me->state = CON_IDLE;
                                if (bind_me->kill_me == 1) {
                                        RemoveContext(bind_me);
                                } 
                                write(rescan[1], &junk, 1);
                        }
-                       else {
-                               lprintf(9, "Thread %02d found nothing to do!\n",
-                                       getpid());
-                       }
 
                }
                dead_session_purge();
+               if ((time(NULL) - last_timer) > 60L) {
+                       last_timer = time(NULL);
+                       PerformSessionHooks(EVT_TIMER);
+               }
        }
 
+       /* If control reaches this point, the server is shutting down */        
+       master_cleanup();
+       --num_threads;
        pthread_exit(NULL);
 }