CWTimer.h

/*******************************************************************************************
 * Copyright (c) 2006-7 Laboratorio di Sistemi di Elaborazione e Bioingegneria Informatica *
 *                      Universita' Campus BioMedico - Italy                               *
 *                                                                                         *
 * This program is free software; you can redistribute it and/or modify it under the terms *
 * of the GNU General Public License as published by the Free Software Foundation; either  *
 * version 2 of the License, or (at your option) any later version.                        *
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 * PARTICULAR PURPOSE. See the GNU General Public License for more details.                *
 *                                                                                         *
 * You should have received a copy of the GNU General Public License along with this       *
 * program; if not, write to the:                                                          *
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,                    *
 * MA  02111-1307, USA.                                                                    *
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 * In addition, as a special exception, the copyright holders give permission to link the  *
 * code of portions of this program with the OpenSSL library under certain conditions as   *
 * described in each individual source file, and distribute linked combinations including  * 
 * the two. You must obey the GNU General Public License in all respects for all of the    *
 * code used other than OpenSSL.  If you modify file(s) with this exception, you may       *
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 * If you delete this exception statement from all source files in the program, then also  *
 * delete it here.                                                                         *
 * 
 * --------------------------------------------------------------------------------------- *
 * Project:  Capwap                                                                        *
 *                                                                                         *
 * Author :  Ludovico Rossi (ludo@bluepixysw.com)                                          *  
 *           Del Moro Andrea (andrea_delmoro@libero.it)                                    *
 *           Giovannini Federica (giovannini.federica@gmail.com)                           *
 *           Massimo Vellucci (m.vellucci@unicampus.it)                                    *
 *           Mauro Bisson (mauro.bis@gmail.com)                                            *
 *******************************************************************************************/


/* This file implements routines for handling timeouts. 
 * 
 * User calls are: 
 *   _clkini() - initialize clock and timers 
 *   _setimr() - set a timer 
 *   _cantim() - cancel a timer 
 *   #disable_interrupts - disable clock and timer interrupts 
 *   #enable_interrupts - enable clock and timer interrupts 
 * 
 * 
 * History: 
 *     Originally written for standalone MC68000 with MC6840 timer 
 *     Ed Barkmeyer, NBS, September 1983 
 * 
 *     Rewritten for 4.2BSD UNIX with software timer. 
 *     Don Libes, NBS, October 1985 
 * 
 */ 

#include "CWCommon.h" 

#include <signal.h> 
#include <sys/time.h> 

#ifdef DMALLOC
#include "../dmalloc-5.5.0/dmalloc.h"
#endif

#ifndef TRUE 
#define TRUE    1 
#define FALSE   0 
#endif

typedef short int       int2; 
typedef int             int4; 
#define TIMER_SIGNAL_TYPE       CW_TIMER_INTERNAL_SIGNAL
#define TIMER_INTERVAL_TYPE     ITIMER_REAL 
struct itimerval timer_value;

static unsigned timer_set_timestamp;    /* this holds the value of */ 
                                        /* current_time() whenever an */ 
                                        /* interval timer is started */ 
/* The following definitions support conversions between the basic unit of 
time in the nip (which is tens-of-milliseconds) and time in all the 4.2BSD 
system calls (which is seconds and microseconds). 
*/ 
#define USECS_PER_MSEC          1000 
#define MSECS_PER_SEC           1000 
#define USECS_PER_SEC           1000000 
#define MANY_TENS_OF_MSECS      (~0)            /* unsigned, please */ 
/* useful for converting from 4.2BSD to nip units */ 
#define USECS_PER_TEN_MSECS     (USECS_PER_MSEC*10) 
#define TENS_OF_MSECS_PER_SEC   (MSECS_PER_SEC/10) 
/* useful for converting from nip units to 4.2 units */ 
#define SEC(x)                  (x/TENS_OF_MSECS_PER_SEC) 
#define USEC(x)					((x*USECS_PER_TEN_MSECS)%USECS_PER_SEC) 
/* 
A timer wakeup queue should be represented as a data structure that can 
do 
MIN, INSERT, DELETE and TRAVERSE operations in minimal time. 
 INSERT and 
DELETE are necessary to support declaring and cancelling of timers MIN 
is 
necessary to find out who has timed out and to decide what the next 
interval 
to timeout should be.  TRAVERSE is necessary for updating all the 
timers once 
a time period has elapsed.  Unfortunately, I forget what this optimal data 
structure is.  Until I remember, we shall use an array.   
The array is used as follows:  Each entry in the array has a timeout.   
We will constantly be waiting for the entry with the shortest timeout. 
When that times out, we will subtract from each timer's timeout, the time 
that 
has passed since we first started waiting for the current timer.   
When a timeout occurs, the event flag is set.  A timer is released from 
use when the timeout is 0 AND the event flag points to 0. 
*/

#define timer_inuse(t)  (t->timeout || t->event) 
struct timer { 
        unsigned int timeout;           /* clock ticks to wait for */ 
        int2 *event;                    /* set to TRUE when time out occurs */
		void (*ast)(void*, int);
		CWTimerArg myArg;
} timerq[CW_TIMER_MAX];                   /* timer queue */ 
struct timer *next_timer;               /* timer we expect to run down next */ 
struct timer *shortest_timer(); 
int oldmask;                            /* signal mask */ 
sigset_t mask;

/* actually these just fiddle with the interrupt from the timer */ 
#define disable_interrupts()    pthread_sigmask(SIG_BLOCK, &mask, NULL); //oldmask = sigblock(1<<(TIMER_SIGNAL_TYPE-1))

#define enable_interrupts()    pthread_sigmask(SIG_UNBLOCK, &mask, NULL); 


/* used when cancelling timers (if that works) */ 
struct itimerval cancel_timer = {{ 0,0},{0,0}}; 

void _clkini();
int _setimr(unsigned int timeout, int2 *event, void (*ast)(void*, int), CWTimerArg myArg, int4 arg, char *pname, CWTimerID *idPtr);
int _cantim(CWTimerID *idPtr);
void start_timer(struct timer *t); 
void cancel_itimer();
void update_all_timers_by(unsigned int time); 

__inline__ CWBool CWTimersInitLib() {
	sigemptyset(&mask);
    	sigaddset(&mask, SIGALRM);
	enable_interrupts();
	_clkini();
	
	return CW_TRUE;
}

void CWTimersInit()
{
	memset(timerq, 0, sizeof(struct timer) * CW_TIMER_MAX);
}

// create a timer that expires after sec seconds. ID of the timer will be returned in *idPtr,
// hdl() will be called with argument arg when the timer expires.
__inline__ CWBool CWTimerCreate(int sec, CWTimerID *idPtr, void (*hdl)(CWTimerArg, CWTimerID), CWTimerArg arg) {
 	int2 ev;
	if(idPtr == NULL || hdl == NULL) return CWErrorRaise(CW_ERROR_WRONG_ARG, NULL);
	
	if(_setimr(sec*100, &ev, (void*) hdl, arg, 0, NULL, idPtr) == -1) {
		return CWErrorRaise(CW_ERROR_NEED_RESOURCE, "Out of Timers");
	}
	
	return CW_TRUE;
}

__inline__ CWTimerArg CWTimerGetArg(CWTimerID *idPtr) 
{
	CWTimerArg pResult;
	
	if(idPtr == NULL)
	{
		CWErrorRaise(CW_ERROR_WRONG_ARG, NULL);
		return (CWTimerArg)NULL;
	}

	// From _cantim
	disable_interrupts(); 

	pResult = timerq[*idPtr].myArg;
	
	enable_interrupts(); 

	return pResult;
}

__inline__ CWBool CWTimerSetArg(CWTimerID *idPtr, CWTimerArg arg) 
{
	if(idPtr == NULL)
	{
		CWErrorRaise(CW_ERROR_WRONG_ARG, NULL);
		return CW_FALSE;
	}

	// From _cantim
	disable_interrupts(); 

	timerq[*idPtr].myArg = arg;
	
	enable_interrupts(); 

	return CW_TRUE;
}


__inline__ CWBool CWTimerDestroy(CWTimerID *idPtr) {
	if(idPtr == NULL) return CWErrorRaise(CW_ERROR_WRONG_ARG, NULL);

	if(_cantim(idPtr) == TRUE) return CW_TRUE;
	else return CWErrorRaise(CW_ERROR_NEED_RESOURCE, "Can't Destroy: Timer not Found");
}

// CAPWAP note: don't use directly the following functions, just use the CWTimer*() wrappers

void clk_isr(); 
unsigned int current_time();

stack_t new_stack;
struct sigaction siga;

// init timers
void _clkini() { 
        struct timer *t; 
        /* disable constant interval timing */
        timerclear(&timer_value.it_interval);
/*
	if (signal(TIMER_SIGNAL_TYPE, clk_isr) == SIG_ERR) { 
                perror("_clkini: signal failed\n"); 
                exit(-1); 
        }
*/
	if ((new_stack.ss_sp = malloc(SIGSTKSZ)) == NULL) {

		perror("impossibile allocare memeoria per il nuovo stack");
	}

	new_stack.ss_size = SIGSTKSZ;
	new_stack.ss_flags = 0;

	if (sigaltstack(&new_stack, NULL) < 0) {

    		perror("sigaltstack");
	}

	siga.sa_handler = clk_isr;
	sigfillset( &siga.sa_mask );
	siga.sa_flags = SA_ONSTACK;

	if ( sigaction(TIMER_SIGNAL_TYPE, &siga, NULL) ) {

		perror("_clkini: signal failed\n"); 
                exit(-1); 
	}

        for (t=timerq;t<&timerq[CW_TIMER_MAX];t++) { 
                t->timeout = 0; 
                t->event = 0; 
        } 
}


int _setimr(	unsigned int timeout,		/* time to wait in 10msec ticks */ 
		int2 *event,			/* event flag to set on runout */ 
		void (*ast)(void*, int),	/* routine to be called on runout or 0 */ 
		CWTimerArg myArg,		
		int4 arg,			/* argument to be provided to timeout ast */ 
		char *pname,
		CWTimerID *idPtr) { 
        struct timer *free_timer;       /* pointer to unused timer entry */ 
        struct timer *t; 
        *event = 0; 

        if (timeout == 0) { /* no time, so enable it and don't put on queue */ 
                *event = TRUE; 
                return(TRUE); 
        } 
        disable_interrupts(); 
        for (*idPtr = 0, t=timerq;t<&timerq[CW_TIMER_MAX];t++, (*idPtr)++) { 
                if (!timer_inuse(t)) { 
//                        CWDebugLog("Found free timer"); 
			free_timer = t; 
                        break; 
                } 
        } 
        if (t == &timerq[CW_TIMER_MAX]) {
			CWDebugLog("Free timer not found"); 
			enable_interrupts()
			return -1; // out of timers
        }
		
        /* install new timer */ 
        /* cannot initialize free timer here, because cancel_itimer() will */ 
        /* munge with it, so push it into the branches of the the if */ 

        if (!next_timer) {
//		CWDebugLog("First Timer\n");
		/* no timers set at all, so this is shortest */ 
                free_timer->event = event; 
                free_timer->timeout = timeout; 
		free_timer->ast= ast;
		free_timer->myArg = myArg;
                start_timer(free_timer); 
        } else if ((timeout + current_time()) < 
                (next_timer->timeout + timer_set_timestamp)) { 
//				CWDebugLog("Shorter Timer\n");
                /* new timer is shorter than current one, so */ 
                /* cancel current timer and set up new one */ 
                /* not sure if the next setitimer() is actually necessary */ 
                /* probably not, but I haven't tested to make sure */ 
                cancel_itimer(); 
                free_timer->event = event; 
                free_timer->timeout = timeout;
		free_timer->ast= ast;
		free_timer->myArg = myArg;
                start_timer(free_timer); 
        } else { 
                /* new timer is longer, than current one */ 
//		CWDebugLog("Longer Timer (%d)\n", timeout);
                free_timer->event = event; 
                free_timer->timeout = timeout + (current_time() - timer_set_timestamp);
		free_timer->ast= ast;
		free_timer->myArg = myArg;
	}
		
	CWDebugLog("timer set, index:%d, timeout:%d", *idPtr, timerq[*idPtr].timeout);
        enable_interrupts(); 
        return(TRUE); 
} 

// cancel a timer
int _cantim(CWTimerID *idPtr) { 
        struct timer *t; 

        disable_interrupts(); 
       // for (t=timerq;t<&timerq[CW_TIMER_MAX];t++) { 
                t = &timerq[*idPtr];
				//if (t->event == event) { 
                        t->timeout = 0; 
                        t->event = 0;
						t->myArg = 0;
                        /* check if we were waiting on this one */ 
                        if (t == next_timer) { 
                                cancel_itimer(); 
                                start_timer(shortest_timer()); 
                        } 
                        enable_interrupts(); 
                        return(TRUE); 
                //} 
        //} 
        enable_interrupts(); 
        return(FALSE); 
} 

/* clock interrupt handler */ 
/* this routine is executed when an alarm signal occurs */ 
void clk_isr() { 
	CWDebugLog("Signal Timer Expired received");
        /* the following condition could be set up, 
        if the interrupt was delivered while we were in cantim, cancelling 
        the last timer */ 
		//printf("\n\n\n%d\n\n", pthread_self());
	CWDebugLog("Subtract %d from timers", current_time() - timer_set_timestamp);
        update_all_timers_by(current_time() - timer_set_timestamp);
		if (next_timer == 0) return;
		  /* start timer for next shortest guy if one exists */ 
        start_timer(shortest_timer()); 
} 
/* subtract time from all timers, enabling any that run out along the way */ 
void update_all_timers_by(unsigned int time) { 
	struct timer *t; int id;
	CWDebugLog("Update Timers");
        for (id=0, t=timerq;t<&timerq[CW_TIMER_MAX];t++, id++) { 
		if (t->timeout) {
//			CWDebugLog("~~~~~~~~~timer set, index:%d, timeout:%d~~~~~~~~~~~~", id, t->timeout);
                        if (time < t->timeout) { 
			//	CWDebugLog("timeout(%d) - time(%d)\n", t->timeout, time);
				t->timeout -= time;
			//	CWDebugLog("timeout(%d)\n", t->timeout);
                        } else {
			//	CWDebugLog("(%d) %d vs %d\n", t, t->timeout, time);
//				CWDebugLog("~~~~~~~è un segnale mio!~~~~~~~~~");
				t->timeout = 0;
				(t->ast)((void *)t->myArg, id);
				//	printf("%d vs %d\n", t->timeout, time);
                                /* if this has forced a timeout on */ 
                                /* anyone else, enable it */ 
                                *t->event = TRUE; 
                                t->event = 0;        /* remove timer */ 
                        } 
                } 
        } 
} 
struct timer *shortest_timer() { 
        struct timer *t, *s_t;  /* shortest_timer */ 
        unsigned int old_timer = MANY_TENS_OF_MSECS; 
        for (s_t = 0,t=timerq;t<&timerq[CW_TIMER_MAX];t++) { 
                if (t->timeout > 0 && t->timeout < old_timer) { 
                        old_timer = t->timeout; 
                        s_t = t; 
                } 
        } 
        return(s_t); 
} 
void start_timer(t) 
struct timer *t; 
{ 
        next_timer = t;         /* remember for _cantim and _setimr */ 
        if (!t) return; 
        timer_set_timestamp = current_time(); 
        timer_value.it_value.tv_sec = SEC(next_timer->timeout); 
        timer_value.it_value.tv_usec = USEC(next_timer->timeout);
//	CWDebugLog("Start System Timer (%d,%d)", timer_value.it_value.tv_sec, timer_value.it_value.tv_usec);
        if (-1 == setitimer(TIMER_INTERVAL_TYPE,&timer_value, (struct itimerval *)0)) { 
                perror("start_timer: setitimer"); 
                exit(-1); 
        } 
}

/* return time in tens of milliseconds */ 
unsigned int 
current_time() 
{ 
        struct timeval tp; 
        (void) gettimeofday(&tp,(struct timezone *)0); 
        /* ignore overflow */ 
        return(tp.tv_sec*TENS_OF_MSECS_PER_SEC 
                + tp.tv_usec/USECS_PER_TEN_MSECS); 
}

void cancel_itimer() 
{ 
        if (-1 == setitimer(TIMER_INTERVAL_TYPE,&cancel_timer, 
                                       (struct itimerval *)0)) { 
                perror("_setimr: setitimer failed"); 
                exit(-1); 
        } 
        update_all_timers_by(current_time() - timer_set_timestamp); 
}