HUGE PATCH. This moves all of mime_parser.c and all
[citadel.git] / citadel / sysdep.c
index 930e8cf71be1335110f442f84cc4c62ab0933918..14676acfb552e038528181142399497c25121de7 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * $Id$
  *
- * Citadel/UX "system dependent" stuff.
+ * Citadel "system dependent" stuff.
  * See copyright.txt for copyright information.
  *
  * Here's where we (hopefully) have most parts of the Citadel server that
  *
  */
 
-#ifdef DLL_EXPORT
-#define IN_LIBCIT
-#endif
-
 #include "sysdep.h"
 #include <stdlib.h>
 #include <unistd.h>
@@ -27,6 +23,7 @@
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <sys/socket.h>
+#include <syslog.h>
 #include <sys/syslog.h>
 
 #if TIME_WITH_SYS_TIME
 #endif
 
 #include <limits.h>
+#include <sys/resource.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
 #include <netdb.h>
 #include <sys/un.h>
 #include <string.h>
 #ifdef HAVE_PTHREAD_H
 #include <pthread.h>
 #endif
+#include <libcitadel.h>
 #include "citadel.h"
 #include "server.h"
-#include "serv_extensions.h"
 #include "sysdep_decls.h"
 #include "citserver.h"
 #include "support.h"
 #include "config.h"
 #include "database.h"
 #include "housekeeping.h"
-#include "tools.h"
-#include "serv_crypto.h"
+#include "modules/crypto/serv_crypto.h"        /* Needed for init_ssl, client_write_ssl, client_read_ssl, destruct_ssl */
+#include "ecrash.h"
 
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
 #include "snprintf.h"
 #endif
 
+
 #ifdef DEBUG_MEMORY_LEAKS
-struct TheHeap *heap = NULL;
+struct igheap {
+       struct igheap *next;
+       char file[32];
+       int line;
+       void *block;
+};
+
+struct igheap *igheap = NULL;
 #endif
 
+
 pthread_mutex_t Critters[MAX_SEMAPHORES];      /* Things needing locking */
 pthread_key_t MyConKey;                                /* TSD key for MyContext() */
 
 int verbosity = DEFAULT_VERBOSITY;             /* Logging level */
 
 struct CitContext masterCC;
-int rescan[2];                                 /* The Rescan Pipe */
 time_t last_purge = 0;                         /* Last dead session purge */
 static int num_threads = 0;                    /* Current number of threads */
 int num_sessions = 0;                          /* Current number of sessions */
 
-fd_set masterfds;                              /* Master sockets etc. */
-int masterhighest;
+int syslog_facility = LOG_DAEMON;
+int enable_syslog = 0;
 
-pthread_t initial_thread;              /* tid for main() thread */
+void DestroyWorkerList(void);
 
-int syslog_facility = (-1);
+
+/*
+ * Create an interface to lprintf that follows the coding convention.
+ * This is here until such time as we have replaced all calls to lprintf with CtdlLogPrintf
+ */
+void CtdlLogPrintf(enum LogLevel loglevel, const char *format, ...)
+{
+       va_list arg_ptr;
+       va_start(arg_ptr, format);
+       vlprintf(loglevel, format, arg_ptr);
+       va_end(arg_ptr);
+}
 
 
 /*
  * lprintf()  ...   Write logging information
- * 
- * Note: the variable "buf" below needs to be large enough to handle any
- * log data sent through this function.  BE CAREFUL!
  */
-void lprintf(int loglevel, const char *format, ...) {   
-        va_list arg_ptr;
-       char buf[SIZ];
-  
-        va_start(arg_ptr, format);   
-        vsnprintf(buf, sizeof(buf), format, arg_ptr);   
-        va_end(arg_ptr);   
-
-       if (syslog_facility >= 0) {
-               if (loglevel <= verbosity) {
-                       syslog(LOG_NOTICE, buf);
-               }
+void lprintf(enum LogLevel loglevel, const char *format, ...) {   
+       va_list arg_ptr;
+       va_start(arg_ptr, format);
+       vlprintf(loglevel, format, arg_ptr);
+       va_end(arg_ptr);
+}
+
+void vlprintf(enum LogLevel loglevel, const char *format, va_list arg_ptr)
+{
+       char buf[SIZ], buf2[SIZ];
+
+       if (enable_syslog) {
+               vsyslog((syslog_facility | loglevel), format, arg_ptr);
        }
-       else if (loglevel <= verbosity) { 
+
+       /* stderr output code */
+       if (enable_syslog || running_as_daemon) return;
+
+       /* if we run in forground and syslog is disabled, log to terminal */
+       if (loglevel <= verbosity) { 
                struct timeval tv;
-               struct tm *tim;
+               struct tm tim;
                time_t unixtime;
 
                gettimeofday(&tv, NULL);
                /* Promote to time_t; types differ on some OSes (like darwin) */
                unixtime = tv.tv_sec;
-               tim = localtime(&unixtime);
-               /*
-                * Log provides millisecond accuracy.  If you need
-                * microsecond accuracy and your OS supports it, change
-                * %03ld to %06ld and remove " / 1000" after tv.tv_usec.
-                */
-               if (CC && CC->cs_pid) {
-                       fprintf(stderr,
-                               "%04d/%02d/%02d %2d:%02d:%02d.%03ld [%3d] %s",
-                               tim->tm_year + 1900, tim->tm_mon + 1,
-                               tim->tm_mday, tim->tm_hour, tim->tm_min,
-                               tim->tm_sec, (long)tv.tv_usec / 1000,
-                               CC->cs_pid, buf);
+               localtime_r(&unixtime, &tim);
+               if (CC->cs_pid != 0) {
+                       sprintf(buf,
+                               "%04d/%02d/%02d %2d:%02d:%02d.%06ld [%3d] ",
+                               tim.tm_year + 1900, tim.tm_mon + 1,
+                               tim.tm_mday, tim.tm_hour, tim.tm_min,
+                               tim.tm_sec, (long)tv.tv_usec,
+                               CC->cs_pid);
                } else {
-                       fprintf(stderr,
-                               "%04d/%02d/%02d %2d:%02d:%02d.%03ld %s",
-                               tim->tm_year + 1900, tim->tm_mon + 1,
-                               tim->tm_mday, tim->tm_hour, tim->tm_min,
-                               tim->tm_sec, (long)tv.tv_usec / 1000, buf);
+                       sprintf(buf,
+                               "%04d/%02d/%02d %2d:%02d:%02d.%06ld ",
+                               tim.tm_year + 1900, tim.tm_mon + 1,
+                               tim.tm_mday, tim.tm_hour, tim.tm_min,
+                               tim.tm_sec, (long)tv.tv_usec);
                }
+               vsprintf(buf2, format, arg_ptr);   
+
+               fprintf(stderr, "%s%s", buf, buf2);
                fflush(stderr);
        }
-
-       PerformLogHooks(loglevel, buf);
 }   
 
 
 
-#ifdef DEBUG_MEMORY_LEAKS
-void *tracked_malloc(size_t tsize, char *tfile, int tline) {
-       void *ptr;
-       struct TheHeap *hptr;
-
-       ptr = malloc(tsize);
-       if (ptr == NULL) {
-               lprintf(3, "DANGER!  mallok(%d) at %s:%d failed!\n",
-                       tsize, tfile, tline);
-               return(NULL);
-       }
-
-       hptr = (struct TheHeap *) malloc(sizeof(struct TheHeap));
-       strcpy(hptr->h_file, tfile);
-       hptr->h_line = tline;
-       hptr->next = heap;
-       hptr->h_ptr = ptr;
-       heap = hptr;
-       return ptr;
-}
-
-char *tracked_strdup(const char *orig, char *tfile, int tline) {
-       char *s;
-
-       s = tracked_malloc( (strlen(orig)+1), tfile, tline);
-       if (s == NULL) return NULL;
-
-       strcpy(s, orig);
-       return s;
-}
-
-void tracked_free(void *ptr) {
-       struct TheHeap *hptr, *freeme;
+/*
+ * Signal handler to shut down the server.
+ */
 
-       if (heap->h_ptr == ptr) {
-               hptr = heap->next;
-               free(heap);
-               heap = hptr;
-       }
-       else {
-               for (hptr=heap; hptr->next!=NULL; hptr=hptr->next) {
-                       if (hptr->next->h_ptr == ptr) {
-                               freeme = hptr->next;
-                               hptr->next = hptr->next->next;
-                               free(freeme);
-                       }
-               }
-       }
+volatile int time_to_die = 0;
+volatile int shutdown_and_halt = 0;
+volatile int restart_server = 0;
+volatile int running_as_daemon = 0;
 
-       free(ptr);
+static RETSIGTYPE signal_cleanup(int signum) {
+       lprintf(CTDL_DEBUG, "Caught signal %d; shutting down.\n", signum);
+       time_to_die = 1;
+       master_cleanup(signum);
 }
 
-void *tracked_realloc(void *ptr, size_t size) {
-       void *newptr;
-       struct TheHeap *hptr;
-       
-       newptr = realloc(ptr, size);
-
-       for (hptr=heap; hptr!=NULL; hptr=hptr->next) {
-               if (hptr->h_ptr == ptr) hptr->h_ptr = newptr;
-       }
 
-       return newptr;
-}
 
 
-void dump_tracked() {
-       struct TheHeap *hptr;
+void InitialiseSemaphores(void)
+{
+       int i;
 
-       cprintf("%d Here's what's allocated...\n", LISTING_FOLLOWS);    
-       for (hptr=heap; hptr!=NULL; hptr=hptr->next) {
-               cprintf("%20s %5d\n",
-                       hptr->h_file, hptr->h_line);
+       /* Set up a bunch of semaphores to be used for critical sections */
+       for (i=0; i<MAX_SEMAPHORES; ++i) {
+               pthread_mutex_init(&Critters[i], NULL);
        }
-#ifdef __GNUC__
-        malloc_stats();
-#endif
-
-       cprintf("000\n");
 }
-#endif
 
 
-/*
- * We used to use master_cleanup() as a signal handler to shut down the server.
- * however, master_cleanup() and the functions it calls do some things that
- * aren't such a good idea to do from a signal handler: acquiring mutexes,
- * playing with signal masks on BSDI systems, etc. so instead we install the
- * following signal handler to set a global variable to inform the main loop
- * that it's time to call master_cleanup() and exit.
- */
-
-volatile int time_to_die = 0;
-
-static RETSIGTYPE signal_cleanup(int signum) {
-       time_to_die = 1;
-}
-
 
 /*
  * Some initialization stuff...
  */
 void init_sysdep(void) {
-       int a;
+       sigset_t set;
+
+       /* Avoid vulnerabilities related to FD_SETSIZE if we can. */
+#ifdef FD_SETSIZE
+#ifdef RLIMIT_NOFILE
+       struct rlimit rl;
+       getrlimit(RLIMIT_NOFILE, &rl);
+       rl.rlim_cur = FD_SETSIZE;
+       rl.rlim_max = FD_SETSIZE;
+       setrlimit(RLIMIT_NOFILE, &rl);
+#endif
+#endif
 
+       /* If we've got OpenSSL, we're going to use it. */
 #ifdef HAVE_OPENSSL
        init_ssl();
 #endif
 
-       /* 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.
         * We only need a single pointer per thread - it points to the
@@ -271,17 +228,31 @@ void init_sysdep(void) {
         * session to which the calling thread is currently bound.
         */
        if (pthread_key_create(&MyConKey, NULL) != 0) {
-               lprintf(1, "Can't create TSD key!!  %s\n", strerror(errno));
+               lprintf(CTDL_CRIT, "Can't create TSD key: %s\n",
+                       strerror(errno));
        }
 
        /*
         * The action for unexpected signals and exceptions should be to
         * call signal_cleanup() to gracefully shut down the server.
         */
+       sigemptyset(&set);
+       sigaddset(&set, SIGINT);
+       sigaddset(&set, SIGQUIT);
+       sigaddset(&set, SIGHUP);
+       sigaddset(&set, SIGTERM);
+       // sigaddset(&set, SIGSEGV);    commented out because
+       // sigaddset(&set, SIGILL);     we want core dumps
+       // sigaddset(&set, SIGBUS);
+       sigprocmask(SIG_UNBLOCK, &set, NULL);
+
        signal(SIGINT, signal_cleanup);
        signal(SIGQUIT, signal_cleanup);
        signal(SIGHUP, signal_cleanup);
        signal(SIGTERM, signal_cleanup);
+       // signal(SIGSEGV, signal_cleanup);     commented out because
+       // signal(SIGILL, signal_cleanup);      we want core dumps
+       // signal(SIGBUS, signal_cleanup);
 
        /*
         * Do not shut down the server on broken pipe signals, otherwise the
@@ -297,10 +268,20 @@ void init_sysdep(void) {
  */
 void begin_critical_section(int which_one)
 {
-       /* lprintf(9, "begin_critical_section(%d)\n", which_one); */
-       /* ensure nobody ever tries to do a critical section within a
-          transaction; this could lead to deadlock. */
-       cdb_check_handles();
+       /* lprintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
+
+       /* For all types of critical sections except those listed here,
+        * ensure nobody ever tries to do a critical section within a
+        * transaction; this could lead to deadlock.
+        */
+       if (    (which_one != S_FLOORCACHE)
+#ifdef DEBUG_MEMORY_LEAKS
+               && (which_one != S_DEBUGMEMLEAKS)
+#endif
+               && (which_one != S_RPLIST)
+       ) {
+               cdb_check_handles();
+       }
        pthread_mutex_lock(&Critters[which_one]);
 }
 
@@ -309,7 +290,6 @@ 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]);
 }
 
@@ -320,7 +300,7 @@ void end_critical_section(int which_one)
  * a TCP port.  The server shuts down if the bind fails.
  *
  */
-int ig_tcp_server(int port_number, int queue_len)
+int ig_tcp_server(char *ip_addr, int port_number, int queue_len, char **errormessage)
 {
        struct sockaddr_in sin;
        int s, i;
@@ -331,14 +311,26 @@ int ig_tcp_server(int port_number, int queue_len)
 
        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 (ip_addr == NULL) {
+               sin.sin_addr.s_addr = INADDR_ANY;
+       }
+       else {
+               sin.sin_addr.s_addr = inet_addr(ip_addr);
+       }
+                                                                               
+       if (sin.sin_addr.s_addr == !INADDR_ANY) {
+               sin.sin_addr.s_addr = INADDR_ANY;
+       }
 
        s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
 
        if (s < 0) {
-               lprintf(1, "citserver: Can't create a socket: %s\n",
-                       strerror(errno));
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                                "citserver: Can't create a socket: %s",
+                                strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
                return(-1);
        }
 
@@ -346,14 +338,32 @@ int ig_tcp_server(int port_number, int queue_len)
        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));
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                                "citserver: Can't bind: %s",
+                                strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
+               close(s);
+               return(-1);
+       }
+
+       /* set to nonblock - we need this for some obscure situations */
+       if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                                "citserver: Can't set socket to non-blocking: %s",
+                                strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
                close(s);
                return(-1);
        }
 
        if (listen(s, actual_queue_len) < 0) {
-               lprintf(1, "citserver: Can't listen: %s\n", strerror(errno));
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                                "citserver: Can't listen: %s",
+                                strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
                close(s);
                return(-1);
        }
@@ -366,7 +376,7 @@ int ig_tcp_server(int port_number, int queue_len)
 /*
  * Create a Unix domain socket and listen on it
  */
-int ig_uds_server(char *sockpath, int queue_len)
+int ig_uds_server(char *sockpath, int queue_len, char **errormessage)
 {
        struct sockaddr_un addr;
        int s;
@@ -378,8 +388,10 @@ int ig_uds_server(char *sockpath, int queue_len)
 
        i = unlink(sockpath);
        if (i != 0) if (errno != ENOENT) {
-               lprintf(1, "citserver: can't unlink %s: %s\n",
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, "citserver: can't unlink %s: %s",
                        sockpath, strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
                return(-1);
        }
 
@@ -389,23 +401,44 @@ int ig_uds_server(char *sockpath, int queue_len)
 
        s = socket(AF_UNIX, SOCK_STREAM, 0);
        if (s < 0) {
-               lprintf(1, "citserver: Can't create a socket: %s\n",
-                       strerror(errno));
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                        "citserver: Can't create a socket: %s",
+                        strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
                return(-1);
        }
 
        if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
-               lprintf(1, "citserver: Can't bind: %s\n",
-                       strerror(errno));
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                        "citserver: Can't bind: %s",
+                        strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
+               return(-1);
+       }
+
+       /* set to nonblock - we need this for some obscure situations */
+       if (fcntl(s, F_SETFL, O_NONBLOCK) < 0) {
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                        "citserver: Can't set socket to non-blocking: %s",
+                        strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
+               close(s);
                return(-1);
        }
 
        if (listen(s, actual_queue_len) < 0) {
-               lprintf(1, "citserver: Can't listen: %s\n", strerror(errno));
+               *errormessage = (char*) malloc(SIZ + 1);
+               snprintf(*errormessage, SIZ, 
+                        "citserver: Can't listen: %s",
+                        strerror(errno));
+               lprintf(CTDL_EMERG, "%s\n", *errormessage);
                return(-1);
        }
 
-       chmod(sockpath, 0777);
+       chmod(sockpath, S_ISGID|S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IWGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH);
        return(s);
 }
 
@@ -416,12 +449,14 @@ int ig_uds_server(char *sockpath, int queue_len)
  * called this function.  If there's no such binding (for example, if it's
  * called by the housekeeper thread) then a generic 'master' CC is returned.
  *
- * It's inlined because it's used *VERY* frequently.
+ * This function is used *VERY* frequently and must be kept small.
  */
-INLINE struct CitContext *MyContext(void) {
-       return ((pthread_getspecific(MyConKey) == NULL)
-               ? &masterCC
-               : (struct CitContext *) pthread_getspecific(MyConKey)
+struct CitContext *MyContext(void) {
+
+       register struct CitContext *c;
+
+       return ((c = (struct CitContext *) pthread_getspecific(MyConKey),
+               c == NULL) ? &masterCC : c
        );
 }
 
@@ -430,15 +465,15 @@ INLINE struct CitContext *MyContext(void) {
  * Initialize a new context and place it in the list.  The session number
  * used to be the PID (which is why it's called cs_pid), but that was when we
  * had one process per session.  Now we just assign them sequentially, starting
- * at 1 (don't change it to 0 because masterCC uses 0) and re-using them when
- * sessions terminate.
+ * at 1 (don't change it to 0 because masterCC uses 0).
  */
 struct CitContext *CreateNewContext(void) {
-       struct CitContext *me, *ptr;
+       struct CitContext *me;
+       static int next_pid = 0;
 
-       me = (struct CitContext *) mallok(sizeof(struct CitContext));
+       me = (struct CitContext *) malloc(sizeof(struct CitContext));
        if (me == NULL) {
-               lprintf(1, "citserver: can't allocate memory!!\n");
+               lprintf(CTDL_ALERT, "citserver: can't allocate memory!!\n");
                return NULL;
        }
        memset(me, 0, sizeof(struct CitContext));
@@ -449,72 +484,98 @@ struct CitContext *CreateNewContext(void) {
         */
        me->state = CON_EXECUTING;
 
-
        /*
         * Generate a unique session number and insert this context into
         * the list.
         */
        begin_critical_section(S_SESSION_TABLE);
-
-       if (ContextList == NULL) {
-               ContextList = me;
-               me->cs_pid = 1;
-               me->next = NULL;
-       }
-
-       else if (ContextList->cs_pid > 1) {
-               me->next = ContextList;
-               ContextList = me;
-               me->cs_pid = 1;
+       me->cs_pid = ++next_pid;
+       me->prev = NULL;
+       me->next = ContextList;
+       ContextList = me;
+       if (me->next != NULL) {
+               me->next->prev = me;
        }
-
-       else {
-               for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
-                       if (ptr->next == NULL) {
-                               ptr->next = me;
-                               me->cs_pid = ptr->cs_pid + 1;
-                               me->next = NULL;
-                               goto DONE;
-                       }
-                       else if (ptr->next->cs_pid > (ptr->cs_pid+1)) {
-                               me->next = ptr->next;
-                               ptr->next = me;
-                               me->cs_pid = ptr->cs_pid + 1;
-                               goto DONE;
-                       }
-               }
-       }
-
-DONE:  ++num_sessions;
+       ++num_sessions;
        end_critical_section(S_SESSION_TABLE);
        return(me);
 }
 
 
 /*
- * buffer_output() ... tell client_write to buffer all output until
- *                     instructed to dump it all out later
+ * The following functions implement output buffering. If the kernel supplies
+ * native TCP buffering (Linux & *BSD), use that; otherwise, emulate it with
+ * user-space buffering.
  */
+#ifndef HAVE_DARWIN
+#ifdef TCP_CORK
+#      define HAVE_TCP_BUFFERING
+#else
+#      ifdef TCP_NOPUSH
+#              define HAVE_TCP_BUFFERING
+#              define TCP_CORK TCP_NOPUSH
+#      endif
+#endif /* TCP_CORK */
+#endif /* HAVE_DARWIN */
+
+#ifdef HAVE_TCP_BUFFERING
+static unsigned on = 1, off = 0;
+void buffer_output(void) {
+       struct CitContext *ctx = MyContext();
+       setsockopt(ctx->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
+       ctx->buffering = 1;
+}
+
+void unbuffer_output(void) {
+       struct CitContext *ctx = MyContext();
+       setsockopt(ctx->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
+       ctx->buffering = 0;
+}
+
+void flush_output(void) {
+       struct CitContext *ctx = MyContext();
+       setsockopt(ctx->client_socket, IPPROTO_TCP, TCP_CORK, &off, 4);
+       setsockopt(ctx->client_socket, IPPROTO_TCP, TCP_CORK, &on, 4);
+}
+#else 
+#ifdef HAVE_DARWIN
+/* Stub functions for Darwin/OS X where TCP buffering isn't liked at all */
+void buffer_output(void) {
+       CC->buffering = 0;
+}
+void unbuffer_output(void) {
+       CC->buffering = 0;
+}
+void flush_output(void) {
+}
+#else
 void buffer_output(void) {
        if (CC->buffering == 0) {
                CC->buffering = 1;
                CC->buffer_len = 0;
-               CC->output_buffer = mallok(SIZ);
+               CC->output_buffer = malloc(SIZ);
+       }
+}
+
+void flush_output(void) {
+       if (CC->buffering == 1) {
+               client_write(CC->output_buffer, CC->buffer_len);
+               CC->buffer_len = 0;
        }
 }
 
-/*
- * unbuffer_output()  ...  dump out all that output we've been buffering.
- */
 void unbuffer_output(void) {
        if (CC->buffering == 1) {
                CC->buffering = 0;
+               /* We don't call flush_output because we can't. */
                client_write(CC->output_buffer, CC->buffer_len);
-               phree(CC->output_buffer);
-               CC->output_buffer = NULL;
                CC->buffer_len = 0;
+               free(CC->output_buffer);
+               CC->output_buffer = NULL;
        }
 }
+#endif /* HAVE_DARWIN */
+#endif /* HAVE_TCP_BUFFERING */
 
 
 
@@ -525,46 +586,55 @@ void client_write(char *buf, int nbytes)
 {
        int bytes_written = 0;
        int retval;
-       int sock;
+#ifndef HAVE_TCP_BUFFERING
        int old_buffer_len = 0;
-
-       if (CC->redirect_fp != NULL) {
-               fwrite(buf, nbytes, 1, CC->redirect_fp);
+#endif
+       t_context *Ctx;
+
+       Ctx = CC;
+       if (Ctx->redirect_buffer != NULL) {
+               if ((Ctx->redirect_len + nbytes + 2) >= Ctx->redirect_alloc) {
+                       Ctx->redirect_alloc = (Ctx->redirect_alloc * 2) + nbytes;
+                       Ctx->redirect_buffer = realloc(Ctx->redirect_buffer,
+                                               Ctx->redirect_alloc);
+               }
+               memcpy(&Ctx->redirect_buffer[Ctx->redirect_len], buf, nbytes);
+               Ctx->redirect_len += nbytes;
+               Ctx->redirect_buffer[Ctx->redirect_len] = 0;
                return;
        }
 
-       if (CC->redirect_sock > 0) {
-               sock = CC->redirect_sock;       /* and continue below... */
-       }
-       else {
-               sock = CC->client_socket;
-       }
-
+#ifndef HAVE_TCP_BUFFERING
        /* If we're buffering for later, do that now. */
-       if (CC->buffering) {
-               old_buffer_len = CC->buffer_len;
-               CC->buffer_len += nbytes;
-               CC->output_buffer = reallok(CC->output_buffer, CC->buffer_len);
-               memcpy(&CC->output_buffer[old_buffer_len], buf, nbytes);
+       if (Ctx->buffering) {
+               old_buffer_len = Ctx->buffer_len;
+               Ctx->buffer_len += nbytes;
+               Ctx->output_buffer = realloc(Ctx->output_buffer, Ctx->buffer_len);
+               memcpy(&Ctx->output_buffer[old_buffer_len], buf, nbytes);
                return;
        }
+#endif
 
        /* Ok, at this point we're not buffering.  Go ahead and write. */
 
 #ifdef HAVE_OPENSSL
-       if (CC->redirect_ssl) {
+       if (Ctx->redirect_ssl) {
                client_write_ssl(buf, nbytes);
                return;
        }
 #endif
 
        while (bytes_written < nbytes) {
-               retval = write(sock, &buf[bytes_written],
+               retval = write(Ctx->client_socket, &buf[bytes_written],
                        nbytes - bytes_written);
                if (retval < 1) {
-                       lprintf(2, "client_write() failed: %s\n",
-                               strerror(errno));
-                       if (sock == CC->client_socket) CC->kill_me = 1;
+                       lprintf(CTDL_ERR,
+                               "client_write(%d bytes) failed: %s (%d)\n",
+                               nbytes - bytes_written,
+                               strerror(errno), errno);
+                       cit_backtrace();
+                       // lprintf(CTDL_DEBUG, "Tried to send: %s",  &buf[bytes_written]);
+                       Ctx->kill_me = 1;
                        return;
                }
                bytes_written = bytes_written + retval;
@@ -574,15 +644,15 @@ void client_write(char *buf, int nbytes)
 
 /*
  * cprintf()  ...   Send formatted printable data to the client.   It is
- *                  implemented in terms of client_write() but remains in
- *                  sysdep.c in case we port to somewhere without va_args...
+ *               implemented in terms of client_write() but remains in
+ *               sysdep.c in case we port to somewhere without va_args...
  */
 void cprintf(const char *format, ...) {   
-        va_list arg_ptr;   
-        char buf[SIZ];   
+       va_list arg_ptr;   
+       char buf[1024];   
    
-        va_start(arg_ptr, format);   
-        if (vsnprintf(buf, sizeof buf, format, arg_ptr) == -1)
+       va_start(arg_ptr, format);   
+       if (vsnprintf(buf, sizeof buf, format, arg_ptr) == -1)
                buf[sizeof buf - 2] = '\n';
        client_write(buf, strlen(buf)); 
        va_end(arg_ptr);
@@ -601,6 +671,7 @@ int client_read_to(char *buf, int bytes, int timeout)
 {
        int len,rlen;
        fd_set rfds;
+       int fd;
        struct timeval tv;
        int retval;
 
@@ -610,23 +681,23 @@ int client_read_to(char *buf, int bytes, int timeout)
        }
 #endif
        len = 0;
+       fd = CC->client_socket;
        while(len<bytes) {
                FD_ZERO(&rfds);
-               FD_SET(CC->client_socket, &rfds);
+               FD_SET(fd, &rfds);
                tv.tv_sec = timeout;
                tv.tv_usec = 0;
 
-               retval = select( (CC->client_socket)+1, 
-                                       &rfds, NULL, NULL, &tv);
+               retval = select( (fd)+1, 
+                                &rfds, NULL, NULL, &tv);
 
-               if (FD_ISSET(CC->client_socket, &rfds) == 0) {
+               if (FD_ISSET(fd, &rfds) == 0) {
                        return(0);
                }
 
-               rlen = read(CC->client_socket, &buf[len], bytes-len);
+               rlen = read(fd, &buf[len], bytes-len);
                if (rlen<1) {
-                       lprintf(2, "client_read() failed: %s\n",
-                               strerror(errno));
+                       /* The socket has been disconnected! */
                        CC->kill_me = 1;
                        return(-1);
                }
@@ -647,11 +718,11 @@ INLINE int client_read(char *buf, int bytes)
 
 
 /*
- * client_gets()   ...   Get a LF-terminated line of text from the client.
+ * client_getln()   ...   Get a LF-terminated line of text from the client.
  * (This is implemented in terms of client_read() and could be
  * justifiably moved out of sysdep.c)
  */
-int client_gets(char *buf)
+int client_getln(char *buf, int bufsize)
 {
        int i, retval;
 
@@ -659,22 +730,26 @@ int client_gets(char *buf)
         */
        for (i = 0;;i++) {
                retval = client_read(&buf[i], 1);
-               if (retval != 1 || buf[i] == '\n' || i == (SIZ-1))
+               if (retval != 1 || buf[i] == '\n' || i == (bufsize-1))
                        break;
        }
 
        /* If we got a long line, discard characters until the newline.
         */
-       if (i == (SIZ-1))
+       if (i == (bufsize-1))
                while (buf[i] != '\n' && retval == 1)
                        retval = client_read(&buf[i], 1);
 
-       /* Strip the trailing newline and any trailing nonprintables (cr's)
+       /* Strip the trailing LF, and the trailing CR if present.
         */
        buf[i] = 0;
-       while ((strlen(buf)>0)&&(!isprint(buf[strlen(buf)-1])))
-               buf[strlen(buf)-1] = 0;
-       if (retval < 0) strcpy(buf, "000");
+       while ( (i > 0)
+               && ( (buf[i - 1]==13)
+                    || ( buf[i - 1]==10)) ) {
+               i--;
+               buf[i] = 0;
+       }
+       if (retval < 0) safestrncpy(&buf[i], "000", bufsize - i);
        return(retval);
 }
 
@@ -686,6 +761,7 @@ int client_gets(char *buf)
 void sysdep_master_cleanup(void) {
        struct ServiceFunctionHook *serviceptr;
 
+/////  DestroyWorkerList();
        /*
         * close all protocol master sockets
         */
@@ -693,11 +769,11 @@ void sysdep_master_cleanup(void) {
            serviceptr = serviceptr->next ) {
 
                if (serviceptr->tcp_port > 0)
-                       lprintf(3, "Closing listener on port %d\n",
+                       lprintf(CTDL_INFO, "Closing listener on port %d\n",
                                serviceptr->tcp_port);
 
                if (serviceptr->sockpath != NULL)
-                       lprintf(3, "Closing listener on '%s'\n",
+                       lprintf(CTDL_INFO, "Closing listener on '%s'\n",
                                serviceptr->sockpath);
 
                close(serviceptr->msock);
@@ -707,9 +783,28 @@ void sysdep_master_cleanup(void) {
                        unlink(serviceptr->sockpath);
                }
        }
+#ifdef HAVE_OPENSSL
+       destruct_ssl();
+#endif
+       serv_calendar_destroy();
+       CtdlDestroyProtoHooks();
+       CtdlDestroyDeleteHooks();
+       CtdlDestroyXmsgHooks();
+       CtdlDestroyNetprocHooks();
+       CtdlDestroyUserHooks();
+       CtdlDestroyMessageHook();
+       CtdlDestroyCleanupHooks();
+       CtdlDestroyFixedOutputHooks();  
+       CtdlDestroySessionHooks();
+       CtdlDestroyServiceHook();
+       #ifdef HAVE_BACKTRACE
+       eCrash_Uninit();
+       #endif
 }
 
 
+
+
 /*
  * Terminate another session.
  * (This could justifiably be moved out of sysdep.c because it
@@ -727,22 +822,103 @@ void kill_session(int session_to_kill) {
        end_critical_section(S_SESSION_TABLE);
 }
 
-
+pid_t current_child;
+void graceful_shutdown(int signum) {
+       kill(current_child, signum);
+       unlink(file_pid_file);
+       exit(0);
+}
 
 
 /*
- * Start running as a daemon.  Only close stdio if do_close_stdio is set.
+ * Start running as a daemon.
  */
-void start_daemon(int do_close_stdio) {
-       if (do_close_stdio) {
-               /* close(0); */
-               close(1);
-               close(2);
+void start_daemon(int unused) {
+       int status = 0;
+       pid_t child = 0;
+       FILE *fp;
+       int do_restart = 0;
+
+       current_child = 0;
+
+       /* Close stdin/stdout/stderr and replace them with /dev/null.
+        * We don't just call close() because we don't want these fd's
+        * to be reused for other files.
+        */
+       chdir(ctdl_run_dir);
+
+       child = fork();
+       if (child != 0) {
+               exit(0);
        }
-       signal(SIGHUP,SIG_IGN);
-       signal(SIGINT,SIG_IGN);
-       signal(SIGQUIT,SIG_IGN);
-       if (fork()!=0) exit(0);
+       
+       signal(SIGHUP, SIG_IGN);
+       signal(SIGINT, SIG_IGN);
+       signal(SIGQUIT, SIG_IGN);
+
+       setsid();
+       umask(0);
+        freopen("/dev/null", "r", stdin);
+        freopen("/dev/null", "w", stdout);
+        freopen("/dev/null", "w", stderr);
+
+       do {
+               current_child = fork();
+
+               signal(SIGTERM, graceful_shutdown);
+       
+               if (current_child < 0) {
+                       perror("fork");
+                       exit(errno);
+               }
+       
+               else if (current_child == 0) {
+                       return; /* continue starting citadel. */
+               }
+       
+               else {
+                       fp = fopen(file_pid_file, "w");
+                       if (fp != NULL) {
+               /*
+                * NB.. The pid file contains the pid of the actual server.
+                * This is not the pid of the watcher process
+                */
+                               fprintf(fp, ""F_PID_T"\n", current_child);
+                               fclose(fp);
+                       }
+                       waitpid(current_child, &status, 0);
+               }
+
+               do_restart = 0;
+
+               /* Did the main process exit with an actual exit code? */
+               if (WIFEXITED(status)) {
+
+                       /* Exit code 0 means the watcher should exit */
+                       if (WEXITSTATUS(status) == 0) {
+                               do_restart = 0;
+                       }
+
+                       /* Exit code 101-109 means the watcher should exit */
+                       else if ( (WEXITSTATUS(status) >= 101) && (WEXITSTATUS(status) <= 109) ) {
+                               do_restart = 0;
+                       }
+
+                       /* Any other exit code means we should restart. */
+                       else {
+                               do_restart = 1;
+                       }
+               }
+
+               /* Any other type of termination (signals, etc.) should also restart. */
+               else {
+                       do_restart = 1;
+               }
+
+       } while (do_restart);
+
+       unlink(file_pid_file);
+       exit(WEXITSTATUS(status));
 }
 
 
@@ -780,36 +956,117 @@ void create_worker(void) {
        struct worker_node *n;
        pthread_attr_t attr;
 
-       n = mallok(sizeof(struct worker_node));
+       n = malloc(sizeof(struct worker_node));
        if (n == NULL) {
-               lprintf(1, "can't allocate worker_node, exiting\n");
+               lprintf(CTDL_EMERG, "can't allocate worker_node, exiting\n");
                time_to_die = -1;
                return;
        }
 
        if ((ret = pthread_attr_init(&attr))) {
-               lprintf(1, "pthread_attr_init: %s\n", strerror(ret));
+               lprintf(CTDL_EMERG, "pthread_attr_init: %s\n", strerror(ret));
                time_to_die = -1;
                return;
        }
 
-       /* we seem to need something bigger than FreeBSD's default 64k stack */
-
-       if ((ret = pthread_attr_setstacksize(&attr, 128 * 1024))) {
-               lprintf(1, "pthread_attr_setstacksize: %s\n", strerror(ret));
+       /* Our per-thread stacks need to be bigger than the default size,
+        * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
+        * crashes on 64-bit Linux.
+        */
+       if ((ret = pthread_attr_setstacksize(&attr, THREADSTACKSIZE))) {
+               lprintf(CTDL_EMERG, "pthread_attr_setstacksize: %s\n",
+                       strerror(ret));
                time_to_die = -1;
+               pthread_attr_destroy(&attr);
                return;
        }
 
        if ((ret = pthread_create(&n->tid, &attr, worker_thread, NULL) != 0))
        {
 
-               lprintf(1, "Can't create worker thread: %s\n",
+               lprintf(CTDL_ALERT, "Can't create worker thread: %s\n",
                        strerror(ret));
        }
 
        n->next = worker_list;
        worker_list = n;
+       pthread_attr_destroy(&attr);
+}
+
+void DestroyWorkerList(void)
+{
+       struct CitContext *ptr;         /* general-purpose utility pointer */
+       struct CitContext *rem = NULL;  /* list of sessions to be destroyed */
+
+       begin_critical_section(S_SESSION_TABLE);
+       ptr = ContextList;
+       while (ptr != NULL){
+               /* Remove the session from the active list */
+               rem = ptr->next;
+               --num_sessions;
+               
+               lprintf(CTDL_DEBUG, "Purging session %d\n", rem->cs_pid);
+               end_critical_section(S_SESSION_TABLE);
+               RemoveContext(ptr);
+               begin_critical_section(S_SESSION_TABLE);
+               free (ptr);
+               ptr = rem;
+       }
+       end_critical_section(S_SESSION_TABLE);
+
+       struct worker_node *cur, *p;
+       cur = worker_list;
+       while (cur != NULL)
+       {
+               p = cur->next;
+               free (cur);
+               cur = p;
+       }
+       worker_list = NULL;
+}
+
+/*
+ * Create the maintenance threads and begin their operation.
+ */
+void create_maintenance_threads(void) {
+       int ret;
+       pthread_attr_t attr;
+
+       if ((ret = pthread_attr_init(&attr))) {
+               lprintf(CTDL_EMERG, "pthread_attr_init: %s\n", strerror(ret));
+               time_to_die = -1;
+               return;
+       }
+
+       /* Our per-thread stacks need to be bigger than the default size,
+        * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
+        * crashes on 64-bit Linux.
+        */
+       if ((ret = pthread_attr_setstacksize(&attr, THREADSTACKSIZE))) {
+               lprintf(CTDL_EMERG, "pthread_attr_setstacksize: %s\n",
+                       strerror(ret));
+               time_to_die = -1;
+               pthread_attr_destroy(&attr);
+               return;
+       }
+       
+       struct MaintenanceThreadHook *fcn;
+
+       lprintf(CTDL_DEBUG, "Performing startup of maintenance thread hooks\n");
+
+       for (fcn = MaintenanceThreadHookTable; fcn != NULL; fcn = fcn->next) {
+               if ((ret = pthread_create(&(fcn->MaintenanceThread_tid), &attr, fcn->fcn_ptr, NULL) != 0)) {
+                       lprintf(CTDL_ALERT, "Can't create thread: %s\n", strerror(ret));
+               }
+               else
+               {
+                       lprintf(CTDL_NOTICE, "Spawned a new maintenance thread \"%s\" (%ld). \n", fcn->name,
+                               fcn->MaintenanceThread_tid);
+               }
+       }
+
+
+       pthread_attr_destroy(&attr);
 }
 
 
@@ -818,101 +1075,74 @@ void create_worker(void) {
  * Purge all sessions which have the 'kill_me' flag set.
  * 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.
+ * of CPU time and keep the context list locked too much.  To force it to run
+ * anyway, set "force" to nonzero.
+ *
  *
- * After that's done, we raise or lower the size of the worker thread pool
+ * After that's done, we raise the size of the worker thread pool
  * if such an action is appropriate.
  */
-void dead_session_purge(void) {
-       struct CitContext *ptr, *rem;
-       struct worker_node **node, *tmp;
-       pthread_t self;
+void dead_session_purge(int force) {
+       struct CitContext *ptr;         /* general-purpose utility pointer */
+       struct CitContext *rem = NULL;  /* list of sessions to be destroyed */
 
-       if ( (time(NULL) - last_purge) < 5 ) return;    /* Too soon, go away */
+       if (force == 0) {
+               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;
+       begin_critical_section(S_SESSION_TABLE);
+       for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
+               if ( (ptr->state == CON_IDLE) && (ptr->kill_me) ) {
+
+                       /* Remove the session from the active list */
+                       if (ptr->prev) {
+                               ptr->prev->next = ptr->next;
+                       }
+                       else {
+                               ContextList = ptr->next;
+                       }
+                       if (ptr->next) {
+                               ptr->next->prev = ptr->prev;
                        }
-               }
-               end_critical_section(S_SESSION_TABLE);
 
-               /* RemoveContext() enters its own S_SESSION_TABLE critical
-                * section, so we have to do it like this.
-                */     
-               if (rem != NULL) {
-                       lprintf(9, "Purging session %d\n", rem->cs_pid);
-                       RemoveContext(rem);
-               }
+                       --num_sessions;
 
-       } while (rem != NULL);
+                       /* And put it on our to-be-destroyed list */
+                       ptr->next = rem;
+                       rem = ptr;
 
+               }
+       }
+       end_critical_section(S_SESSION_TABLE);
 
-       /* Raise or lower the size of the worker thread pool if such
-        * an action is appropriate.
+       /* Now that we no longer have the session list locked, we can take
+        * our time and destroy any sessions on the to-be-killed list, which
+        * is allocated privately on this thread's stack.
         */
+       while (rem != NULL) {
+               lprintf(CTDL_DEBUG, "Purging session %d\n", rem->cs_pid);
+               RemoveContext(rem);
+               ptr = rem;
+               rem = rem->next;
+               free(ptr);
+       }
 
-       self = pthread_self();
-
+       /* Raise the size of the worker thread pool if necessary. */
        if ( (num_sessions > num_threads)
           && (num_threads < config.c_max_workers) ) {
                begin_critical_section(S_WORKER_LIST);
                create_worker();
                end_critical_section(S_WORKER_LIST);
        }
-       
-       /* don't let the initial thread die since it's responsible for
-          waiting for all the other threads to terminate. */
-       else if ( (num_sessions < num_threads)
-          && (num_threads > config.c_min_workers)
-          && (self != initial_thread) ) {
-               cdb_free_tsd();
-               begin_critical_section(S_WORKER_LIST);
-               --num_threads;
-
-               /* we're exiting before server shutdown... unlink ourself from
-                  the worker list and detach our thread to avoid memory leaks
-                */
-
-               for (node = &worker_list; *node != NULL; node = &(*node)->next)
-                       if ((*node)->tid == self) {
-                               tmp = *node;
-                               *node = (*node)->next;
-                               phree(tmp);
-                               break;
-                       }
-
-               pthread_detach(self);
-               end_critical_section(S_WORKER_LIST);
-               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.
@@ -925,37 +1155,7 @@ void InitializeMasterCC(void) {
 
 
 
-/*
- * 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.
- */
-void init_master_fdset(void) {
-       struct ServiceFunctionHook *serviceptr;
-       int m;
-
-       lprintf(9, "Initializing master fdset\n");
-
-       FD_ZERO(&masterfds);
-       masterhighest = 0;
-
-       lprintf(9, "Will listen on rescan pipe %d\n", rescan[0]);
-       FD_SET(rescan[0], &masterfds);
-       if (rescan[0] > masterhighest) masterhighest = rescan[0];
 
-       for (serviceptr = ServiceHookTable; serviceptr != NULL;
-           serviceptr = serviceptr->next ) {
-               m = serviceptr->msock;
-               lprintf(9, "Will listen on master socket %d\n", m);
-               FD_SET(m, &masterfds);
-               if (m > masterhighest) {
-                       masterhighest = m;
-               }
-       }
-       lprintf(9, "masterhighest = %d\n", masterhighest);
-}
 
 
 /*
@@ -972,43 +1172,39 @@ INLINE void become_session(struct CitContext *which_con) {
  */    
 void *worker_thread(void *arg) {
        int i;
-       char junk;
        int highest;
        struct CitContext *ptr;
        struct CitContext *bind_me = NULL;
        fd_set readfds;
-       int retval;
+       int retval = 0;
        struct CitContext *con= NULL;   /* Temporary context pointer */
        struct ServiceFunctionHook *serviceptr;
        int ssock;                      /* Descriptor for client socket */
        struct timeval tv;
+       int force_purge = 0;
+       int m;
 
        num_threads++;
 
        cdb_allocate_tsd();
 
+       // Register for tracing
+       #ifdef HAVE_BACKTRACE
+       eCrash_RegisterThread("WorkerThread", 0);
+       #endif
        while (!time_to_die) {
 
-               /* 
-                * A naive implementation would have all idle threads
-                * calling select() and then they'd all wake up at once
-                * (known in computer science as the "thundering herd"
-                * problem).  We solve this problem by putting the select()
-                * in a critical section, so only one thread has the
-                * opportunity to wake up.  If we wake up on a master
-                * socket, create a new session context; otherwise, just
-                * bind the thread to the context we want and go on our
-                * merry way.
-                */
-
                /* make doubly sure we're not holding any stale db handles
                 * which might cause a deadlock.
                 */
                cdb_check_handles();
+do_select:     force_purge = 0;
+               bind_me = NULL;         /* Which session shall we handle? */
+
+               /* Initialize the fdset. */
+               FD_ZERO(&readfds);
+               highest = 0;
 
-               begin_critical_section(S_I_WANNA_SELECT);
-SETUP_FD:      memcpy(&readfds, &masterfds, sizeof masterfds);
-               highest = masterhighest;
                begin_critical_section(S_SESSION_TABLE);
                for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
                        if (ptr->state == CON_IDLE) {
@@ -1016,26 +1212,51 @@ SETUP_FD:       memcpy(&readfds, &masterfds, sizeof masterfds);
                                if (ptr->client_socket > highest)
                                        highest = ptr->client_socket;
                        }
+                       if ((bind_me == NULL) && (ptr->state == CON_READY)) {
+                               bind_me = ptr;
+                               ptr->state = CON_EXECUTING;
+                       }
                }
                end_critical_section(S_SESSION_TABLE);
 
-               tv.tv_sec = 1;          /* wake up every second if no input */
-               tv.tv_usec = 0;
+               if (bind_me) {
+                       goto SKIP_SELECT;
+               }
 
-               do_select:
-               if (!time_to_die)
+               /* If we got this far, it means that there are no sessions
+                * which a previous thread marked for attention, so we go
+                * ahead and get ready to select().
+                */
+
+               /* First, add the various master sockets to the fdset. */
+               for (serviceptr = ServiceHookTable; serviceptr != NULL;
+               serviceptr = serviceptr->next ) {
+                       m = serviceptr->msock;
+                       FD_SET(m, &readfds);
+                       if (m > highest) {
+                               highest = m;
+                       }
+               }
+
+               if (!time_to_die) {
+                       tv.tv_sec = 1;          /* wake up every second if no input */
+                       tv.tv_usec = 0;
                        retval = select(highest + 1, &readfds, NULL, NULL, &tv);
-               else {
-                       end_critical_section(S_I_WANNA_SELECT);
-                       break;
                }
 
+               if (time_to_die) return(NULL);
+
                /* Now figure out who made this select() unblock.
                 * First, check for an error or exit condition.
                 */
                if (retval < 0) {
+                       if (errno == EBADF) {
+                               lprintf(CTDL_NOTICE, "select() failed: (%s)\n",
+                                       strerror(errno));
+                               goto do_select;
+                       }
                        if (errno != EINTR) {
-                               lprintf(9, "Exiting (%s)\n", strerror(errno));
+                               lprintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
                                time_to_die = 1;
                        } else if (!time_to_die)
                                goto do_select;
@@ -1049,26 +1270,36 @@ SETUP_FD:       memcpy(&readfds, &masterfds, sizeof masterfds);
 
                        if (FD_ISSET(serviceptr->msock, &readfds)) {
                                ssock = accept(serviceptr->msock, NULL, 0);
-                               if (ssock < 0) {
-                                       lprintf(2, "citserver: accept(): %s\n",
-                                               strerror(errno));
-                               }
-                               else {
-                                       lprintf(7, "citserver: "
+                               if (ssock >= 0) {
+                                       lprintf(CTDL_DEBUG,
                                                "New client socket %d\n",
                                                ssock);
 
+                                       /* The master socket is non-blocking but the client
+                                        * sockets need to be blocking, otherwise certain
+                                        * operations barf on FreeBSD.  Not a fatal error.
+                                        */
+                                       if (fcntl(ssock, F_SETFL, 0) < 0) {
+                                               lprintf(CTDL_EMERG,
+                                                       "citserver: Can't set socket to blocking: %s\n",
+                                                       strerror(errno));
+                                       }
+
                                        /* New context will be created already
-                                       * set up in the CON_EXECUTING state.
-                                       */
+                                        * set up in the CON_EXECUTING state.
+                                        */
                                        con = CreateNewContext();
 
-                                       /* Assign new socket number to it. */
+                                       /* Assign our new socket number to it. */
                                        con->client_socket = ssock;
                                        con->h_command_function =
                                                serviceptr->h_command_function;
-
-                                       /* Determine whether local socket */
+                                       con->h_async_function =
+                                               serviceptr->h_async_function;
+                                       con->ServiceName =
+                                               serviceptr->ServiceName;
+                                       
+                                       /* Determine whether it's a local socket */
                                        if (serviceptr->sockpath != NULL)
                                                con->is_local_socket = 1;
        
@@ -1083,70 +1314,67 @@ SETUP_FD:       memcpy(&readfds, &masterfds, sizeof masterfds);
                                        serviceptr->h_greeting_function();
                                        become_session(NULL);
                                        con->state = CON_IDLE;
-                                       goto SETUP_FD;
+                                       goto do_select;
                                }
                        }
                }
 
-               /* If the rescan pipe went active, someone is telling this
-                * thread that the &readfds needs to be refreshed with more
-                * current data.
-                */
-               if (time_to_die) {
-                       end_critical_section(S_I_WANNA_SELECT);
-                       break;
-               }
-
-               if (FD_ISSET(rescan[0], &readfds)) {
-                       read(rescan[0], &junk, 1);
-                       goto SETUP_FD;
-               }
-
                /* It must be a client socket.  Find a context that has data
-                * waiting on its socket *and* is in the CON_IDLE state.
+                * waiting on its socket *and* is in the CON_IDLE state.  Any
+                * active sockets other than our chosen one are marked as
+                * CON_READY so the next thread that comes around can just bind
+                * to one without having to select() again.
                 */
-               else {
-                       bind_me = NULL;
-                       begin_critical_section(S_SESSION_TABLE);
-                       for (ptr = ContextList;
-                           ( (ptr != NULL) && (bind_me == NULL) );
-                           ptr = ptr->next) {
-                               if ( (FD_ISSET(ptr->client_socket, &readfds))
-                                  && (ptr->state == CON_IDLE) ) {
-                                       bind_me = ptr;
+               begin_critical_section(S_SESSION_TABLE);
+               for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
+                       if ( (FD_ISSET(ptr->client_socket, &readfds))
+                          && (ptr->state != CON_EXECUTING) ) {
+                               ptr->input_waiting = 1;
+                               if (!bind_me) {
+                                       bind_me = ptr;  /* I choose you! */
+                                       bind_me->state = CON_EXECUTING;
+                               }
+                               else {
+                                       ptr->state = CON_READY;
                                }
                        }
-                       if (bind_me != NULL) {
-                               /* Found one.  Stake a claim to it before
-                                * letting anyone else touch the context list.
-                                */
-                               bind_me->state = CON_EXECUTING;
-                       }
+               }
+               end_critical_section(S_SESSION_TABLE);
 
-                       end_critical_section(S_SESSION_TABLE);
-                       end_critical_section(S_I_WANNA_SELECT);
+SKIP_SELECT:
+               /* We're bound to a session */
+               if (bind_me != NULL) {
+                       become_session(bind_me);
 
-                       /* We're bound to a session, now do *one* command */
-                       if (bind_me != NULL) {
-                               become_session(bind_me);
+                       /* If the client has sent a command, execute it. */
+                       if (CC->input_waiting) {
                                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);
+                               CC->input_waiting = 0;
                        }
 
+                       /* If there are asynchronous messages waiting and the
+                        * client supports it, do those now */
+                       if ((CC->is_async) && (CC->async_waiting)
+                          && (CC->h_async_function != NULL)) {
+                               CC->h_async_function();
+                               CC->async_waiting = 0;
+                       }
+                       
+                       force_purge = CC->kill_me;
+                       become_session(NULL);
+                       bind_me->state = CON_IDLE;
                }
-               dead_session_purge();
+
+               dead_session_purge(force_purge);
                do_housekeeping();
                check_sched_shutdown();
        }
-
+       if (con != NULL) free (con);//// TODO: could this harm other threads? 
        /* If control reaches this point, the server is shutting down */        
-       --num_threads;
-       return NULL;
+       #ifdef HAVE_BACKTRACE
+       eCrash_UnregisterThread();
+       #endif
+       return(NULL);
 }
 
 
@@ -1188,6 +1416,115 @@ int SyslogFacility(char *name)
                if(!strcasecmp(name, facTbl[i].name))
                        return facTbl[i].facility;
        }
-       return -1;
+       enable_syslog = 0;
+       return LOG_DAEMON;
+}
+
+
+/********** MEM CHEQQER ***********/
+
+#ifdef DEBUG_MEMORY_LEAKS
+
+#undef malloc
+#undef realloc
+#undef strdup
+#undef free
+
+void *tracked_malloc(size_t size, char *file, int line) {
+       struct igheap *thisheap;
+       void *block;
+
+       block = malloc(size);
+       if (block == NULL) return(block);
+
+       thisheap = malloc(sizeof(struct igheap));
+       if (thisheap == NULL) {
+               free(block);
+               return(NULL);
+       }
+
+       thisheap->block = block;
+       strcpy(thisheap->file, file);
+       thisheap->line = line;
+       
+       begin_critical_section(S_DEBUGMEMLEAKS);
+       thisheap->next = igheap;
+       igheap = thisheap;
+       end_critical_section(S_DEBUGMEMLEAKS);
+
+       return(block);
+}
+
+
+void *tracked_realloc(void *ptr, size_t size, char *file, int line) {
+       struct igheap *thisheap;
+       void *block;
+
+       block = realloc(ptr, size);
+       if (block == NULL) return(block);
+
+       thisheap = malloc(sizeof(struct igheap));
+       if (thisheap == NULL) {
+               free(block);
+               return(NULL);
+       }
+
+       thisheap->block = block;
+       strcpy(thisheap->file, file);
+       thisheap->line = line;
+       
+       begin_critical_section(S_DEBUGMEMLEAKS);
+       thisheap->next = igheap;
+       igheap = thisheap;
+       end_critical_section(S_DEBUGMEMLEAKS);
+
+       return(block);
+}
+
+
+
+void tracked_free(void *ptr) {
+       struct igheap *thisheap;
+       struct igheap *trash;
+
+       free(ptr);
+
+       if (igheap == NULL) return;
+       begin_critical_section(S_DEBUGMEMLEAKS);
+       for (thisheap = igheap; thisheap != NULL; thisheap = thisheap->next) {
+               if (thisheap->next != NULL) {
+                       if (thisheap->next->block == ptr) {
+                               trash = thisheap->next;
+                               thisheap->next = thisheap->next->next;
+                               free(trash);
+                       }
+               }
+       }
+       if (igheap->block == ptr) {
+               trash = igheap;
+               igheap = igheap->next;
+               free(trash);
+       }
+       end_critical_section(S_DEBUGMEMLEAKS);
+}
+
+char *tracked_strdup(const char *s, char *file, int line) {
+       char *ptr;
+
+       if (s == NULL) return(NULL);
+       ptr = tracked_malloc(strlen(s) + 1, file, line);
+       if (ptr == NULL) return(NULL);
+       strncpy(ptr, s, strlen(s));
+       return(ptr);
+}
+
+void dump_heap(void) {
+       struct igheap *thisheap;
+
+       for (thisheap = igheap; thisheap != NULL; thisheap = thisheap->next) {
+               lprintf(CTDL_CRIT, "UNFREED: %30s : %d\n",
+                       thisheap->file, thisheap->line);
+       }
 }
 
+#endif /*  DEBUG_MEMORY_LEAKS */