backend.c

/* 92/04/18 - cleaned up stylistically by Sulam@TMI */
#include "std.h"
#include "lpc_incl.h"
#include "backend.h"
#include "comm.h"
#include "replace_program.h"
#include "socket_efuns.h"
#include "call_out.h"
#include "port.h"
#include "master.h"
#include "eval.h"

#ifdef PACKAGE_ASYNC
#include "packages/async.h"
#endif

#ifdef WIN32
#include <process.h>
void CDECL alarm_loop (void *);
#endif

error_context_t *current_error_context = 0;

/*
 * The 'current_time' is updated in the call_out cycles
 */
long current_time;

object_t *current_heart_beat;
static void look_for_objects_to_swap (void);
void call_heart_beat (void);

#if 0
static void report_holes (void);
#endif

/*
 * There are global variables that must be zeroed before any execution.
 * In case of errors, there will be a LONGJMP(), and the variables will
 * have to be cleared explicitely. They are normally maintained by the
 * code that use them.
 *
 * This routine must only be called from top level, not from inside
 * stack machine execution (as stack will be cleared).
 */
void clear_state()
{
	current_object = 0;
	set_command_giver(0);
	current_interactive = 0;
	previous_ob = 0;
	current_prog = 0;
	caller_type = 0;
	reset_machine(0);   /* Pop down the stack. */
}       /* clear_state() */

#if 0
static void report_holes() {
	if (current_object && current_object->name)
		debug_message("current_object is /%s\n", current_object->name);
	if (command_giver && command_giver->name)
		debug_message("command_giver is /%s\n", command_giver->name);
	if (current_interactive && current_interactive->name)
		debug_message("current_interactive is /%s\n", current_interactive->name);
	if (previous_ob && previous_ob->name)
		debug_message("previous_ob is /%s\n", previous_ob->name);
	if (current_prog && current_prog->name)
		debug_message("current_prog is /%s\n", current_prog->name);
	if (caller_type)
		debug_message("caller_type is %s\n", caller_type);
}
#endif

void logon (object_t * ob)
{
	if(ob->flags & O_DESTRUCTED){
		return;
	}
	/* current_object no longer set */
	apply(APPLY_LOGON, ob, 0, ORIGIN_DRIVER);
	/* function not existing is no longer fatal */
}

/*
 * This is the backend. We will stay here for ever (almost).
 */
extern int max_fd;
void backend()
{
	struct timeval timeout;
	int i, nb;
	volatile int first_call = 1;
	int there_is_a_port = 0;
	error_context_t econ;

	debug_message("Initializations complete.\n\n");
	for (i = 0; i < 5; i++) {
		if (external_port[i].port) {
			debug_message("Accepting connections on port %d.\n",
					external_port[i].port);
			there_is_a_port = 1;
		}
	}

	if (!there_is_a_port)
		debug_message("No external ports specified.\n");

	init_user_conn();   /* initialize user connection socket */
#ifdef SIGHUP
	signal(SIGHUP, startshutdownMudOS);
#endif
	clear_state();
	save_context(&econ);
	if (SETJMP(econ.context))
		restore_context(&econ);
	clear_state();
	if (!t_flag && first_call) {
		first_call = 0;
		call_heart_beat();
	}

	while (1) {
		/* Has to be cleared if we jumped out of process_user_command() */
		current_interactive = 0;
		set_eval(max_cost);

		if (obj_list_replace || obj_list_destruct)
			remove_destructed_objects();

		/*
		 * shut down MudOS if MudOS_is_being_shut_down is set.
		 */
		if (MudOS_is_being_shut_down)
			shutdownMudOS(0);
		if (slow_shut_down_to_do) {
			int tmp = slow_shut_down_to_do;

			slow_shut_down_to_do = 0;
			slow_shut_down(tmp);
		}
		/*
		 * select
		 */
		make_selectmasks();
		timeout.tv_sec = 1;
		timeout.tv_usec = 0;
#ifndef hpux
		nb = select(max_fd + 1, &readmask, &writemask, (fd_set *) 0, &timeout);
#else
		nb = select(max_fd + 1, (int *) &readmask, (int *) &writemask,
				(int *) 0, &timeout);
#endif
		/*
		 * process I/O if necessary.
		 */
		if (nb > 0) {
			process_io();
		}
		/*
		 * process user commands.
		 */
		for (i = 0; process_user_command() && i < max_users; i++)
			;

		/*
		 * call outs
		 */
		call_out();
#ifdef PACKAGE_ASYNC
		check_reqs();
#endif
	}
}       /* backend() */


/*
 * Despite the name, this routine takes care of several things.
 * It will run once every 15 minutes.
 *
 * . It will attempt to reconnect to the address server if the connection has
 *   been lost.
 * . It will loop through all objects.
 *
 *   . If an object is found in a state of not having done reset, and the
 *     delay to next reset has passed, then reset() will be done.
 *
 *   . If the object has a existed more than the time limit given for swapping,
 *     then 'clean_up' will first be called in the object
 *
 * There are some problems if the object self-destructs in clean_up, so
 * special care has to be taken of how the linked list is used.
 */
static void look_for_objects_to_swap()
{
	static int next_time;
#ifndef NO_IP_DEMON
	extern int no_ip_demon;
	static int next_server_time;
#endif
	object_t *ob;
	VOLATILE object_t *next_ob, *last_good_ob;
	error_context_t econ;

#ifndef NO_IP_DEMON
	if (current_time >= next_server_time) {
		/* initialize the address server.  if it is already initialized, then
		 * this is a nop.  this will cause the driver to reattempt connecting
		 * to the address server once every 15 minutes in the event that it
		 * has gone down.
		 */
		if (!no_ip_demon && next_server_time)
			init_addr_server(ADDR_SERVER_IP, ADDR_SERVER_PORT);
		next_server_time = current_time + 15 * 60;
	}
#endif

	if (current_time < next_time)
		return;     /* Not time to look yet */
	next_time = current_time + 5 * 60; /* Next time is in 5 minutes */

	/*
	 * Objects object can be destructed, which means that next object to
	 * investigate is saved in next_ob. If very unlucky, that object can be
	 * destructed too. In that case, the loop is simply restarted.
	 */
	next_ob = obj_list;
	last_good_ob = obj_list;
	save_context(&econ);
	if (SETJMP(econ.context))
		restore_context(&econ);

	while ((ob = (object_t *)next_ob)) {
		int ready_for_clean_up = 0;

		if (ob->flags & O_DESTRUCTED){
			if(last_good_ob->flags & O_DESTRUCTED)
				ob = obj_list;  /* restart */
			else
				ob = (object_t *)last_good_ob;
		}
		next_ob = ob->next_all;

		/*
		 * Check reference time before reset() is called.
		 */
		if (current_time - ob->time_of_ref > time_to_clean_up)
			ready_for_clean_up = 1;
#if !defined(NO_RESETS) && !defined(LAZY_RESETS)
		/*
		 * Should this object have reset(1) called ?
		 */
		if ((ob->flags & O_WILL_RESET) && (ob->next_reset < current_time)
				&& !(ob->flags & O_RESET_STATE)) {
			debug(d_flag, ("RESET /%s\n", ob->obname));
			set_eval(max_cost);
			reset_object(ob);
			if(ob->flags & O_DESTRUCTED)
				continue;
		}
#endif
		if (time_to_clean_up > 0) {
			/*
			 * Has enough time passed, to give the object a chance to
			 * self-destruct ? Save the O_RESET_STATE, which will be cleared.
			 *
			 * Only call clean_up in objects that has defined such a function.
			 *
			 * Only if the clean_up returns a non-zero value, will it be called
			 * again.
			 */

			if (ready_for_clean_up && (ob->flags & O_WILL_CLEAN_UP)) {
				int save_reset_state = ob->flags & O_RESET_STATE;
				svalue_t *svp;

				debug(d_flag, ("clean up /%s\n", ob->obname));

				/*
				 * Supply a flag to the object that says if this program is
				 * inherited by other objects. Cloned objects might as well
				 * believe they are not inherited. Swapped objects will not
				 * have a ref count > 1 (and will have an invalid ob->prog
				 * pointer).
				 *
				 * Note that if it is in the apply_low cache, it will also
				 * get a flag of 1, which may cause the mudlib not to clean
				 * up the object.  This isn't bad because:
				 * (1) one expects it is rare for objects that have untouched
				 * long enough to clean_up to still be in the cache, especially
				 * on busy MUDs.
				 * (2) the ones that are are the more heavily used ones, so
				 * keeping them around seems justified.
				 */

				push_number(ob->flags & (O_CLONE) ? 0 : ob->prog->ref);
				set_eval(max_cost);
				svp = apply(APPLY_CLEAN_UP, ob, 1, ORIGIN_DRIVER);
				if (ob->flags & O_DESTRUCTED)
					continue;
				if (!svp || (svp->type == T_NUMBER && svp->u.number == 0))
					ob->flags &= ~O_WILL_CLEAN_UP;
				ob->flags |= save_reset_state;
			}
		}
		last_good_ob = ob;
	}
	pop_context(&econ);
}       /* look_for_objects_to_swap() */

/* Call all heart_beat() functions in all objects.  Also call the next reset,
 * and the call out.
 * We do heart beats by moving each object done to the end of the heart beat
 * list before we call its function, and always using the item at the head
 * of the list as our function to call.  We keep calling heart beats until
 * a timeout or we have done num_heart_objs calls.  It is done this way so
 * that objects can delete heart beating objects from the list from within
 * their heart beat without truncating the current round of heart beats.
 *
 * Set command_giver to current_object if it is a living object. If the object
 * is shadowed, check the shadowed object if living. There is no need to save
 * the value of the command_giver, as the caller resets it to 0 anyway.  */

typedef struct {
	object_t *ob;
	short heart_beat_ticks;
	short time_to_heart_beat;
} heart_beat_t;

static heart_beat_t *heart_beats = 0;
static int max_heart_beats = 0;
static int heart_beat_index = 0;
static int num_hb_objs = 0;
static int num_hb_to_do = 0;

static int num_hb_calls = 0;  /* starts */
static float perc_hb_probes = 100.0;  /* decaying avge of how many complete */

void call_heart_beat()
{
	object_t *ob;
	heart_beat_t *curr_hb;
	error_context_t econ;

	current_interactive = 0;

	if ((num_hb_to_do = num_hb_objs)) {
		num_hb_calls++;
		heart_beat_index = 0;
		save_context(&econ);
		while (1) {
			ob = (curr_hb = &heart_beats[heart_beat_index])->ob;
			DEBUG_CHECK(!(ob->flags & O_HEART_BEAT),
					"Heartbeat not set in object on heartbeat list!");
			/* is it time to do a heart beat ? */
			curr_hb->heart_beat_ticks--;

			if (ob->prog->heart_beat != 0) {
				if (curr_hb->heart_beat_ticks < 1) {
					object_t *new_command_giver;
					curr_hb->heart_beat_ticks = curr_hb->time_to_heart_beat;
					current_heart_beat = ob;
					new_command_giver = ob;
#ifndef NO_SHADOWS
					while (new_command_giver->shadowing)
						new_command_giver = new_command_giver->shadowing;
#endif
#ifndef NO_ADD_ACTION
					if (!(new_command_giver->flags & O_ENABLE_COMMANDS))
						new_command_giver = 0;
#endif
#ifdef PACKAGE_MUDLIB_STATS
					add_heart_beats(&ob->stats, 1);
#endif
					set_eval(max_cost);

					if (SETJMP(econ.context)) {
						restore_context(&econ);
					} else {
						save_command_giver(new_command_giver);
						call_direct(ob, ob->prog->heart_beat - 1,
								ORIGIN_DRIVER, 0);
						pop_stack(); /* pop the return value */
						restore_command_giver();
					}

					current_object = 0;
				}
			}
			if (++heart_beat_index == num_hb_to_do)
				break;
		}
		pop_context(&econ);
		if (heart_beat_index < num_hb_to_do)
			perc_hb_probes = 100 * (float) heart_beat_index / num_hb_to_do;
		else
			perc_hb_probes = 100.0;
		heart_beat_index = num_hb_to_do = 0;
	}
	current_prog = 0;
	current_heart_beat = 0;
	look_for_objects_to_swap();
#ifdef PACKAGE_MUDLIB_STATS
	mudlib_stats_decay();
#endif
}       /* call_heart_beat() */

int
query_heart_beat (object_t * ob)
{
	int index;

	if (!(ob->flags & O_HEART_BEAT))  return 0;
	index = num_hb_objs;
	while (index--) {
		if (heart_beats[index].ob == ob)
			return heart_beats[index].time_to_heart_beat;
	}
	return 0;
}       /* query_heart_beat() */

/* add or remove an object from the heart beat list; does the major check...
 * If an object removes something from the list from within a heart beat,
 * various pointers in call_heart_beat could be stuffed, so we must
 * check current_heart_beat and adjust pointers.  */

int set_heart_beat (object_t * ob, int to)
{
	int index;

	if (ob->flags & O_DESTRUCTED) return 0;

	if (!to) {
		int num;

		index = num_hb_objs;
		while (index--) {
			if (heart_beats[index].ob == ob) break;
		}
		if (index < 0) return 0;

		if (num_hb_to_do) {
			if (index <= heart_beat_index)
				heart_beat_index--;
			if (index < num_hb_to_do)
				num_hb_to_do--;
		}

		if ((num = (num_hb_objs - (index + 1))))
			memmove(heart_beats + index, heart_beats + (index + 1), num * sizeof(heart_beat_t));

		num_hb_objs--;
		ob->flags &= ~O_HEART_BEAT;
		return 1;
	}

	if (ob->flags & O_HEART_BEAT) {
		if (to < 0) return 0;

		index = num_hb_objs;
		while (index--) {
			if (heart_beats[index].ob == ob) {
				heart_beats[index].time_to_heart_beat = heart_beats[index].heart_beat_ticks = to;
				break;
			}
		}
		DEBUG_CHECK(index < 0, "Couldn't find enabled object in heart_beat list!\n");
	} else {
		heart_beat_t *hb;

		if (!max_heart_beats)
			heart_beats = CALLOCATE(max_heart_beats = HEART_BEAT_CHUNK,
					heart_beat_t, TAG_HEART_BEAT,
					"set_heart_beat: 1");
		else if (num_hb_objs == max_heart_beats) {
			max_heart_beats += HEART_BEAT_CHUNK;
			heart_beats = RESIZE(heart_beats, max_heart_beats,
					heart_beat_t, TAG_HEART_BEAT,
					"set_heart_beat: 1");
		}

		hb = &heart_beats[num_hb_objs++];
		hb->ob = ob;
		if (to < 0) to = 1;
		hb->time_to_heart_beat = to;
		hb->heart_beat_ticks = to;
		ob->flags |= O_HEART_BEAT;
	}

	return 1;
}

int heart_beat_status (outbuffer_t * ob, int verbose)
{
	char buf[20];

	if (verbose == 1) {
		outbuf_add(ob, "Heart beat information:\n");
		outbuf_add(ob, "-----------------------\n");
		outbuf_addv(ob, "Number of objects with heart beat: %d, starts: %d\n",
				num_hb_objs, num_hb_calls);

		/* passing floats to varargs isn't highly portable so let sprintf
     handle it */
		sprintf(buf, "%.2f", perc_hb_probes);
		outbuf_addv(ob, "Percentage of HB calls completed last time: %s\n", buf);
	}
	return (0);
}       /* heart_beat_status() */

/* New version used when not in -o mode. The epilog() in master.c is
 * supposed to return an array of files (castles in 2.4.5) to load. The array
 * returned by apply() will be freed at next call of apply(), which means that
 * the ref count has to be incremented to protect against deallocation.
 *
 * The master object is asked to do the actual loading.
 */
void preload_objects (int eflag)
{
	VOLATILE array_t *prefiles;
	svalue_t *ret;
	VOLATILE int ix;
	error_context_t econ;

	save_context(&econ);
	if (SETJMP(econ.context)) {
		restore_context(&econ);
		pop_context(&econ);
		return;
	}
	push_number(eflag);
	ret = apply_master_ob(APPLY_EPILOG, 1);
	pop_context(&econ);
	if ((ret == 0) || (ret == (svalue_t *)-1) || (ret->type != T_ARRAY))
		return;
	else
		prefiles = ret->u.arr;
	if ((prefiles == 0) || (prefiles->size < 1))
		return;

	debug_message("\nLoading preloaded files ...\n");
	prefiles->ref++;
	ix = 0;
	/* in case of an error, effectively do a 'continue' */
	save_context(&econ);
	if (SETJMP(econ.context)) {
		restore_context(&econ);
		ix++;
	}
	for ( ; ix < prefiles->size; ix++) {
		if (prefiles->item[ix].type != T_STRING)
			continue;

		set_eval(max_cost);

		push_svalue(((array_t *)prefiles)->item + ix);
		(void) apply_master_ob(APPLY_PRELOAD, 1);
	}
	free_array((array_t *)prefiles);
	pop_context(&econ);
}       /* preload_objects() */

/* All destructed objects are moved into a sperate linked list,
 * and deallocated after program execution.  */

INLINE void remove_destructed_objects()
{
	object_t *ob, *next;

	if (obj_list_replace)
		replace_programs();
	for (ob = obj_list_destruct; ob; ob = next) {
		next = ob->next_all;
		destruct2(ob);
	}
	obj_list_destruct = 0;
}       /* remove_destructed_objects() */

static double load_av = 0.0;

void update_load_av()
{
	static int last_time;
	int n;
	double c;
	static int acc = 0;

	acc++;
	if (current_time == last_time)
		return;
	n = current_time - last_time;
	if (n < NUM_CONSTS)
		c = consts[n];
	else
		c = exp(-n / 900.0);
	load_av = c * load_av + acc * (1 - c) / n;
	last_time = current_time;
	acc = 0;
}       /* update_load_av() */

static double compile_av = 0.0;

void
update_compile_av (int lines)
{
	static int last_time;
	int n;
	double c;
	static int acc = 0;

	acc += lines;
	if (current_time == last_time)
		return;
	n = current_time - last_time;
	if (n < NUM_CONSTS)
		c = consts[n];
	else
		c = exp(-n / 900.0);
	compile_av = c * compile_av + acc * (1 - c) / n;
	last_time = current_time;
	acc = 0;
}       /* update_compile_av() */

char *query_load_av()
{
	static char buff[100];

	sprintf(buff, "%.2f cmds/s, %.2f comp lines/s", load_av, compile_av);
	return (buff);
}       /* query_load_av() */

#ifdef F_HEART_BEATS
array_t *get_heart_beats() {
	int nob = 0, n = num_hb_objs;
	heart_beat_t *hb = heart_beats;
	object_t **obtab;
	array_t *arr;
#ifdef F_SET_HIDE
	int apply_valid_hide = 1, display_hidden = 0;
#endif
	if(n)
		obtab = CALLOCATE(n, object_t *, TAG_TEMPORARY, "heart_beats");
	else
		obtab = NULL;
	while (n--) {
#ifdef F_SET_HIDE
		if (hb->ob->flags & O_HIDDEN) {
			if (apply_valid_hide) {
				apply_valid_hide = 0;
				display_hidden = valid_hide(current_object);
			}
			if (!display_hidden)
				continue;
		}
#endif
		obtab[nob++] = (hb++)->ob;
	}

	arr = allocate_empty_array(nob);
	while (nob--) {
		arr->item[nob].type = T_OBJECT;
		arr->item[nob].u.ob = obtab[nob];
		add_ref(arr->item[nob].u.ob, "get_heart_beats");
	}
	if(obtab)
		FREE(obtab);

	return arr;
}
#endif