Category : Files from Magazines
Archive   : MAY91.ZIP
Filename : 2N05032A

/*
* File: IOCTL.C
* Purpose: Contains device driver IOCTL
* command function handlers
*/

#include "device.h"

/* External Data */
extern WORD DevHeader;

/* External Functions */
int NetAddname (char *name);
int NetDelname (char *name);
int NetCall (char *local, char *remote, BYTE *session);
int NetSend (FPTR buf, int size, BYTE session);
int NetReceive (FPTR buf, int size, BYTE session);
WORD UnknownCommand (FPTR rh);


/* Global Data */
BYTE localSession = 0;
char clientName[] = "CDROM_CLIENT";
char serverName[] = "CDROM_SERVER";
int dtaInSize[] = { 5, 6, 1, 1,
9, 130, 5, 4,
5, 2, 7, 7,
11, 13, 11, 11 };
int dtaOutSize[] = { 1, 2, 1, 9, 130, 1 };


/*
* IOProcess : General IOCTL (Input/Output) handler
* Sends request header to ther server
* for processing, followed by the DTA.
* First Receive is for the request
* header coming back with status and
* any other data. If all ok second Receive
* is for the DTA stuff.
*/

WORD IOProcess (RH_IO far *rh, int dta_size)
{
int ret;

/** Are we connected? **/
if (!localSession)
return DEV_ERROR | DEV_EGEN | DEV_DONE;

/** Send request header and DTA **/
ret = NetSend (rh, rh->rh.length, localSession);
if (!ret)
ret = NetSend (rh->dta, dta_size,
localSession);

/** Wait for RH to come back **/
if (!ret)
ret = NetReceive (rh, rh->rh.length,
localSession);

/** If good, get dta also **/
if (!ret) {
if (rh->rh.status != 0x100)
/** Error on server **/
return rh->rh.status;

ret = NetReceive (rh->dta, dta_size,
localSession);
}

if (ret)
/** An error occurred somewhere **/
return DEV_ERROR|DEV_DONE|DEV_EREAD;
else
return DEV_DONE;
}

/*
* IOInput0 : Return Device Header Address
* Establishes communications with the CDROM
* server and returns the device header address
* in the data transfer area.
* DTA format is :
* BYTE cmd;
* FPTR address;
*/


WORD IOInput0 (RH_IO far *rh)
{
struct {
BYTE cmd;
FPTR addr;
} far *dta;

/** Attach to server **/
if (NetAddname (clientName) ||
NetCall (clientName, serverName,
&localSession)) {

/** Error making connection **/
NetDelname (clientName);
return DEV_DONE | DEV_ERROR | DEV_EGEN;
}

/** Setup device header address **/
dta = rh->dta;
dta->addr = (void far *) &DevHeader;

return DEV_DONE;
}

/*
* IOInput : IOCTL INPUT function handler
* Dispatches desired request to proper
* IO-In function handler
*/


WORD IOInput (RH_IO far *rh)
{
BYTE io_cmd;

/* first byte of dta buffer has
sub-command code */
io_cmd = *((char far *) (rh->dta));

if (io_cmd == 0)
return IOInput0 (rh);
else if (io_cmd == 1 ||
io_cmd > 2 && io_cmd < 16)
return IOProcess (rh, dtaInSize[io_cmd]);
else
return UnknownCommand (rh);

}


/*
* IOOutput : IOCTL OUTPUT function handler
* Dispatches desired request to proper
* IO-In function handler
*/


WORD IOOutput (RH_IO far *rh)
{
BYTE io_cmd;

/* first byte of dta buffer has
sub-command code */
io_cmd = *((char far *) (rh->dta));

if (io_cmd < 6)
return IOProcess (rh, dtaOutSize[io_cmd]);
else
return UnknownCommand (rh);

}