smaskwait.c

项目描述: slsnif is a serial port logging utility. It listens to the specified serial port and logs all

/* Smaskwait.c: this file contains code which allows one to wait until data
 *  is present given a mask
 */
#include <stdio.h>
#include "xtdio.h"
#define  SSLNEEDTIME
#include "sockets.h"

/* ---------------------------------------------------------------------
 * Local Variables:
 */
static int             waitall = 0;   
static fd_set          mask;  			/* mask last-used by Smaskwait, etc		*/
static struct timeval *timeptr = NULL;
static struct timeval  timewait;
static fd_set          rmask;			/* set by Smaskwait						*/
static int             first   = 1;   

/* ---------------------------------------------------------------------
 * Local Prototypes:
 */

/* ---------------------------------------------------------------------
 * Source Code:
 */

/* Smaskwait: this function waits until some Socket specified to the
 * Smaskset() function receives something.
 *
 * Returns: < 0: error
 *          ==0: timeout
 *          > 0: communication data awaiting
 *
 *   NOTE: THE MASK IS NOT RESET TO ZERO - THE MASK IS RETAINED!!!
 */
#ifdef __PROTOTYPE__
int Smaskwait()
#else
int Smaskwait()
#endif
{
fd_set wmask;			/* write mask */
fd_set emask;			/* error mask */
short  result;


FD_ZERO(&wmask);
FD_ZERO(&emask);

/* test if something is available for reading on the socket.  This form
 * will block (sleep) until something arrives
 */
rmask  = mask;
result = select(waitall, &rmask,&wmask,&emask,timeptr);

if(result < 0) {	/* error */
	return result;
	}

/* result >  0: socket has something waiting 
 * result == 0: timeout
 */
return result;
}

/* --------------------------------------------------------------------- */

/* Smaskset: this function sets up the mask
 *  A null skt clears the mask
 */
#ifdef __PROTOTYPE__
void Smaskset(Socket *skt)
#else
void Smaskset(skt)
Socket *skt;
#endif
{

if(first) {
	FD_ZERO(&mask);
	first= 0;
	}

if(skt) {
	FD_SET(skt->skt,&mask);
	if(skt->skt >= waitall) waitall= skt->skt + 1;
	}
else {
	waitall= 0;
	FD_ZERO(&mask);
	}

}

/* --------------------------------------------------------------------- */

/* Smaskfdset: this function sets up the mask with a "file descriptor"
 * which may be associated with devices other than Sockets
 */
#ifdef __PROTOTYPE__
void Smaskfdset(int fd)
#else
void Smaskfdset(fd)
int fd;
#endif
{

if(first) {
	FD_ZERO(&mask);
	first= 0;
	}

if(0 <= fd && fd < FD_SETSIZE) {	/* fd must be a legal file descriptor */
	FD_SET(fd,&mask);
	if(fd >= waitall) waitall= fd + 1;
	}

}

/* --------------------------------------------------------------------- */

/* Smasktime: this function sets up a timeval structure - specifies a
 * time limit for waiting.  Note: if seconds < 0 or useconds < 0,
 * or seconds == useconds == 0, then there will be no timeout waiting.
 */
#ifdef __PROTOTYPE__
void Smasktime(long seconds,long useconds)
#else
void Smasktime(seconds,useconds)
long seconds;			/* time in seconds			*/
long useconds;			/* time in micro-seconds	*/
#endif
{

if(seconds < 0 || useconds < 0 || (seconds == 0 && useconds == 0)) {
	/* no timeout (ie. infinite wait) */
	timewait.tv_sec = 0L;
	timewait.tv_usec= 0L;
	timeptr         = (struct timeval *) NULL;
	}

else { /* set up specified timeout */
	timewait.tv_sec = seconds;
	timewait.tv_usec= useconds;
	timeptr         = &timewait;
	}

}

/* --------------------------------------------------------------------- */

/* Smasktest: this function allows one to test if any Socket in the
 *  mask has something on it
 * Returns: < 0: error
 *          ==0: timeout
 *          > 0: communication data awaiting
 */
int Smasktest()
{
int ret;
struct timeval timewait_hold;
struct timeval *timeptr_hold=NULL;


/* save current time info */
timewait_hold   = timewait;
timeptr_hold    = timeptr;

/* set up for new time info */
timewait.tv_sec = 0L;
timewait.tv_usec= 0L;
timeptr         = &timewait;

ret= Smaskwait();

/* restore time info */
timewait= timewait_hold;
timeptr = timeptr_hold;

return ret;
}

/* --------------------------------------------------------------------- */

/* Smaskunset: this function sets up the mask
 *  A null skt clears the mask
 */
#ifdef __PROTOTYPE__
void Smaskunset(Socket *skt)
#else
void Smaskunset(skt)
Socket *skt;
#endif
{

if(skt) {
	FD_CLR(skt->skt,&mask);
	}
else {
	waitall= 0;
	FD_ZERO(&mask);
	}

}

/* --------------------------------------------------------------------- */

/* Smaskunfdset: this function sets up the mask
 *  A null skt clears the mask
 */
#ifdef __PROTOTYPE__
void Smaskunfdset(int fd)
#else
void Smaskunfdset(fd)
int fd;
#endif
{

if(fd) FD_CLR(fd,&mask);
else {
	waitall= 0;
	FD_ZERO(&mask);
	}

}

/* --------------------------------------------------------------------- */

/* Smaskget: this function returns the current mask */
#ifdef __PROTOTYPE__
Smask Smaskget()
#else
Smask Smaskget()
#endif
{
Smask smask;


smask.mask   = mask;
smask.waitall= waitall;

return smask;
}

/* --------------------------------------------------------------------- */

/* Smaskuse: this function sets up the mask with the provided mask */
#ifdef __PROTOTYPE__
void Smaskuse(Smask usermask)
#else
void Smaskuse(usermask)
Smask usermask;
#endif
{

mask   = usermask.mask;
waitall= usermask.waitall;

}

/* --------------------------------------------------------------------- */

typedef struct MaskStack_str MaskStack;
struct MaskStack_str {
	Smask      mask;
	MaskStack *nxt,*prv;
	};
static MaskStack *mshd=NULL,*mstl=NULL;

/* Smaskpush: this function pushes the current mask down on a stack
 *  ALSO: the current mask is *cleared*!!!
 */
void Smaskpush()
{
MaskStack *m;


/* allocate */
m= (MaskStack *) malloc(sizeof(MaskStack));

/* link */
if(mstl) mstl->nxt= m;
else     mshd     = m;
m->prv= mstl;
mstl  = m;

/* initialize */
mstl->mask.mask   = mask;
mstl->mask.waitall= waitall;

Smaskset((Socket *) NULL);

}

/* --------------------------------------------------------------------- */

/* Smaskpop: this function pops the stack (or, if the stack is empty,
 *  it will set the current mask to null)
 */
void Smaskpop()
{

if(mstl) {
	MaskStack *old=mstl;

	Smaskuse(mstl->mask);

	/* delink current tail */
	if(mstl->prv) mstl->prv->nxt= NULL;
	else          mshd          = NULL;
	mstl= mstl->prv;

	free((char *) old);
	}
else Smaskset((Socket *) NULL);

}

/* --------------------------------------------------------------------- */

/* Smaskisset: this function tests if a specific Socket is read-ready.
 * Assumption: function is called after a Smaskwait() so that the
 * rmask has been set up.
 */
#ifdef __PROTOTYPE__
int Smaskisset(Socket *skt)
#else
int Smaskisset(skt)
Socket *skt;
#endif
{
int ret;


ret= FD_ISSET(skt->skt,&rmask);

return ret;
}

/* --------------------------------------------------------------------- */

/* Smaskfdisset: this function tests if a specific file descriptor is
 * read-ready
 */
#ifdef __PROTOTYPE__
int Smaskfdisset(int fd)
#else
int Smaskfdisset(fd)
int fd;
#endif
{
int ret;


ret= FD_ISSET(fd,&rmask);

return ret;
}

/* --------------------------------------------------------------------- */


/* ---------------------------------------------------------------------
 * vim: ts=4
 */