filedes.c

T-kernel 的extension源代码

/*
 *----------------------------------------------------------------------
 *    T-Kernel / Standard Extension
 *
 *    Copyright (C) 2006 by Ken Sakamura. All rights reserved.
 *    T-Kernel / Standard Extension is distributed 
 *      under the T-License for T-Kernel / Standard Extension.
 *----------------------------------------------------------------------
 *
 *    Version:   1.00.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2006/8/11.
 *
 *----------------------------------------------------------------------
 */

/*
 *	filedes.c (file)
 *
 *	File management
 *	Manage the file descriptor.
 */

#include "filedes.h"


#define fdtInfop	(&fmInfo.fdtInfo)

#define ENTER		LockFD()
#define EXIT		{ UnlockFD(); return; }
#define RETURN(arg)	{ UnlockFD(); return (arg); }

/*
 * Initialize the file descriptor.
 */
EXPORT ER fmInitFileDescriptorTable( void )
{
	FDT	*fdt;
	W	i;
	ER	err;

	/* Create the lock for exclusive access. */
	err = CreateLock(&fdtInfop->lock, (UB*)"FDes");
	if ( err != E_OK ) {
		goto err_ret1;
	}

	/* Initialize the queue of free list. */
	QueInit(&fdtInfop->freeFD);

	/* Reserve the memory for the file descriptor table. */
	fdt = (FDT*)Vmalloc((size_t)SizeOfFDT);
	if ( fdt == NULL ) {
		err = E_SYSMEM;
		goto err_ret2;
	}
	memset(fdt, 0, (size_t)SizeOfFDT);
	fdtInfop->fdt = fdt;

	/* Register all entries in free list. */
	for ( i = 0; i < MaxOpenFile; ++i ) {
		QueInsert(&(*fdt)[i].q, &fdtInfop->freeFD);
	}

	return E_OK;

	/*
	 * Error processing
	 */
err_ret2:
	DeleteLock(&fdtInfop->lock);
err_ret1:
	DEBUG_PRINT(("fmInitFileDescriptorTable err = %d\n", err));
	return err;
}

/*
 * Delete the file descriptor table.
 */
EXPORT void fmDeleteFileDescriptorTable( void )
{
	Vfree((VB*)fdtInfop->fdt);
	fdtInfop->fdt = NULL;

	DeleteLock(&fdtInfop->lock);
}

/*
 * Retrieve the file descriptor.
 */
EXPORT FD* fmGetFD( W no, PINFO *pinfo )
{
	FD	*fd;

	ENTER;

	if ( !checkFDno(no) ) {
		RETURN (NULL);
	}

	fd = getFDp(no);

	if ( (fd->fs == NULL) || (fd->pinfo != pinfo) ) {
		/* It is a FD of different process or unused entry. */
		RETURN (NULL);
	}

	RETURN (fd);
}

/*
 * Open (Initialize) the file descriptor.
 */
EXPORT FD* fmpOpenFD( PINFO *pinfo, UW omode, OFCB *ofcb, ER *err )
{
	FD	*fd;

	ENTER;

	/* Obtain a free descriptor. */
	fd = (FD*)QueRemoveNext(&fdtInfop->freeFD);
	if ( fd == NULL ) {
		*err = E_LIMIT;
		goto err_ret1;
	}

	/* Initialize the descriptor. */
	fd->fs      = ofcb->fsinfo;
	fd->pinfo   = pinfo;
	fd->ofcb    = ofcb;
	fd->omode   = omode;
	fd->waitReq = NULL;
	QueInit(&fd->mcbq);

	/* Register in OFCB. */
	*err = fmpOpenOFCB(ofcb, omode);
	if ( *err < E_OK ) {
		goto err_ret2;
	}

	/* Define the current record as the first record. */
	fd->crcb = fmpSetCurRCB(FirstRCB(ofcb), ofcb);

	/* Register in the process. */
	LOCK_PINFO_SECTION( QueInsert(&fd->q, &pinfo->file.fdList); );

	RETURN (fd);

err_ret2:
	/* Return to the descriptor free list. */
	fd->fs = NULL;
	QueInsert(&fd->q, &fdtInfop->freeFD);
err_ret1:
	DEBUG_PRINT(("fmpOpenFD err = %d\n", *err));
	RETURN (NULL);
}

/*
 * Close the file descriptor.
 */
EXPORT void fmpCloseFD( FD *fd )
{
	ENTER;

	/* Release the current record. */
	fmpClearCurRCB(fd->crcb, fd->ofcb);

	/* Deregister from the process. */
	LOCK_PINFO_SECTION( QueRemove(&fd->q); );

	/* Deregister from OFCB. */
	fmpCloseOFCB(fd->ofcb, fd->omode);

	/* Return to the descriptor free list. */
	fd->fs = NULL;
	QueInsert(&fd->q, &fdtInfop->freeFD);

	EXIT;
}

/*
 * Check the file open mode.
 */
EXPORT ER fmpCheckFileOpenMode( FD *fd, UW omode )
{
	if ( (fd->omode & omode) != omode ) {
		return E_FD;
	}

	if ( (omode & F_WRITE) != 0U ) {
		if ( isNoWriteFS(fd->fs) != 0 ) {
			return E_RONLY;
		}
	}

	return E_OK;
}

/*
 * Move the current record.
 */
EXPORT void fmpMoveCurRecord( FD *fd, RCB *new )
{
	fmpClearCurRCB(fd->crcb, fd->ofcb);
	fd->crcb = fmpSetCurRCB(new, fd->ofcb);
}