/*-------------------------------------------------------------------*/
int read_omaheaders (DEVBLK *dev, OMATAPE_DESC *omadesc,
BYTE *buf, BYTE *unitstat,BYTE code)
{
int rc; /* Return code */
long blkpos; /* Offset to block header */
S32 curblkl; /* Length of current block */
S32 prvhdro; /* Offset of previous header */
S32 nxthdro; /* Offset of next header */
/* Read the 16-byte block header */
blkpos = dev->nxtblkpos;
rc = readhdr_omaheaders (dev, omadesc, blkpos, &curblkl,
&prvhdro, &nxthdro, unitstat,code);
if (rc < 0) return -1;
/* Update the offsets of the next and previous blocks */
dev->nxtblkpos = nxthdro;
dev->prvblkpos = blkpos;
/* Increment file number and return zero if tapemark */
if (curblkl == -1)
{
close (dev->fd);
dev->fd = -1;
dev->curfilen++;
dev->nxtblkpos = 0;
dev->prvblkpos = -1;
return 0;
}
/* Read data block from tape file */
rc = read (dev->fd, buf, curblkl);
/* Handle read error condition */
if (rc < 0)
{
WRMSG (HHC00204, "E", SSID_TO_LCSS(dev->ssid), dev->devnum, omadesc->filename, "oma", "read()", (off_t)blkpos,
strerror(errno));
/* Set unit check with equipment check */
build_senseX(TAPE_BSENSE_READFAIL,dev,unitstat,code);
return -1;
}
/* Handle end of file within data block */
if (rc < curblkl)
{
WRMSG(HHC00204, "E", SSID_TO_LCSS(dev->ssid), dev->devnum, omadesc->filename, "oma", "read_omaheaders()", (off_t)blkpos, "unexpected end of file");
/* Set unit check with data check and partial record */
build_senseX(TAPE_BSENSE_BLOCKSHORT,dev,unitstat,code);
return -1;
}
/* Return block length */
return curblkl;
} /* end function read_omaheaders */
/*-------------------------------------------------------------------*/
int fsb_omaheaders (DEVBLK *dev, OMATAPE_DESC *omadesc,
BYTE *unitstat,BYTE code)
{
int rc; /* Return code */
long blkpos; /* Offset of block header */
S32 curblkl; /* Length of current block */
S32 prvhdro; /* Offset of previous header */
S32 nxthdro; /* Offset of next header */
/* Initialize current block position */
blkpos = dev->nxtblkpos;
/* Read the 16-byte block header */
rc = readhdr_omaheaders (dev, omadesc, blkpos, &curblkl,
&prvhdro, &nxthdro, unitstat,code);
if (rc < 0) return -1;
/* Check if tapemark was skipped */
if (curblkl == -1)
{
/* Close the current OMA file */
if (dev->fd >= 0)
close (dev->fd);
dev->fd = -1;
dev->nxtblkpos = 0;
dev->prvblkpos = -1;
/* Increment the file number */
dev->curfilen++;
/* Return zero to indicate tapemark */
return 0;
}
/* Update the offsets of the next and previous blocks */
dev->nxtblkpos = nxthdro;
dev->prvblkpos = blkpos;
/* Return block length */
return curblkl;
} /* end function fsb_omaheaders */
/*-------------------------------------------------------------------*/
int bsb_omatape (DEVBLK *dev, BYTE *unitstat,BYTE code)
{
int rc; /* Return code */
OMATAPE_DESC *omadesc; /* -> OMA descriptor entry */
long blkpos; /* Offset of block header */
S32 curblkl; /* Length of current block */
S32 prvhdro; /* Offset of previous header */
S32 nxthdro; /* Offset of next header */
/* Point to the current file entry in the OMA descriptor table */
omadesc = (OMATAPE_DESC*)(dev->omadesc);
omadesc += (dev->curfilen-1);
/* Backspace file if current position is at start of file */
if (dev->nxtblkpos == 0)
{
/* Unit check if already at start of tape */
if (dev->curfilen <= 1)
{
build_senseX(TAPE_BSENSE_LOADPTERR,dev,unitstat,code);
return -1;
}
/* Perform backspace file operation */
rc = bsf_omatape (dev, unitstat,code);
if (rc < 0) return -1;
dev->blockid--;
/* Return zero to indicate tapemark detected */
return 0;
}
/* Unit check if previous block position is unknown */
if (dev->prvblkpos < 0)
{
build_senseX(TAPE_BSENSE_LOADPTERR,dev,unitstat,code);
return -1;
}
/* Backspace to previous block position */
blkpos = dev->prvblkpos;
/* Determine new previous block position */
switch (omadesc->format)
{
case 'H':
/* For OMA headers files, read the previous block header to
extract the block length and new previous block offset */
rc = readhdr_omaheaders (dev, omadesc, blkpos, &curblkl,
&prvhdro, &nxthdro, unitstat,code);
if (rc < 0) return -1;
break;
case 'F':
/* For OMA fixed block files, calculate the new previous
block offset by subtracting the fixed block length */
if (blkpos >= omadesc->blklen)
prvhdro = blkpos - omadesc->blklen;
else
prvhdro = -1;
break;
case 'T':
/* For OMA ASCII text files, new previous block is unknown */
prvhdro = -1;
break;
} /* end switch(omadesc->format) */
/* Update the offsets of the next and previous blocks */
dev->nxtblkpos = blkpos;
dev->prvblkpos = prvhdro;
dev->blockid--;
/* Return +1 to indicate backspace successful */
return +1;
} /* end function bsb_omatape */
/*-------------------------------------------------------------------*/
int bsf_omatape (DEVBLK *dev, BYTE *unitstat,BYTE code)
{
int rc; /* Return code */
off_t pos; /* File position */
OMATAPE_DESC *omadesc; /* -> OMA descriptor entry */
S32 curblkl; /* Length of current block */
S32 prvhdro; /* Offset of previous header */
S32 nxthdro; /* Offset of next header */
/* Close the current OMA file */
if (dev->fd >= 0)
close (dev->fd);
dev->fd = -1;
dev->nxtblkpos = 0;
dev->prvblkpos = -1;
/* Exit with tape at load point if currently on first file */
if (dev->curfilen <= 1)
{
build_senseX(TAPE_BSENSE_LOADPTERR,dev,unitstat,code);
return -1;
}
/* Decrement current file number */
dev->curfilen--;
/* Point to the current file entry in the OMA descriptor table */
omadesc = (OMATAPE_DESC*)(dev->omadesc);
omadesc += (dev->curfilen-1);
/* Open the new current file */
rc = open_omatape (dev, unitstat,code);
if (rc < 0) return rc;
/* Reposition before tapemark header at end of file, or
to end of file for fixed block or ASCII text files */
pos = 0;
if ( 'H' == omadesc->format )
pos -= sizeof(OMATAPE_BLKHDR);
pos = lseek (dev->fd, pos, SEEK_END);
if (pos < 0)
{
/* Handle seek error condition */
logmsg (_("HHCTA265E %4.4X: Error seeking to end of file %s: %s\n"),
dev->devnum, omadesc->filename, strerror(errno));
/* Set unit check with equipment check */
build_senseX(TAPE_BSENSE_LOCATEERR,dev,unitstat,code);
dev->sense[0] = SENSE_EC;
*unitstat = CSW_CE | CSW_DE | CSW_UC;
return -1;
}
dev->nxtblkpos = pos;
dev->prvblkpos = -1;
/* Determine the offset of the previous block */
switch (omadesc->format)
{
case 'H':
/* For OMA headers files, read the tapemark header
and extract the previous block offset */
rc = readhdr_omaheaders (dev, omadesc, pos, &curblkl,
&prvhdro, &nxthdro, unitstat,code);
if (rc < 0) return -1;
dev->prvblkpos = prvhdro;
break;
case 'F':
/* For OMA fixed block files, calculate the previous block
offset allowing for a possible short final block */
pos = (pos + omadesc->blklen - 1) / omadesc->blklen;
dev->prvblkpos = (pos > 0 ? (pos - 1) * omadesc->blklen : -1);
break;
case 'T':
/* For OMA ASCII text files, the previous block is unknown */
dev->prvblkpos = -1;
break;
} /* end switch(omadesc->format) */
/* Return normal status */
return 0;
} /* end function bsf_omatape */
