dev_t get_swap_device()
{
// If a swap device has been specified, then we can short cut all this and just
// use that device.
#ifdef SWAP
return SWAP;
#else
dev_t bd = -1;
int i,j,e;
unsigned int max_size = 0;
struct buf *bp;
struct mbr *mbr;
// First we look for the first active swap device
for(i=0; i<NRDSK; i++)
{
e = rdopen(makedev(i,0),0,S_SILENT);
if(e==0)
{
bp = read_mbr(i);
if(bp)
{
mbr = (struct mbr *)bp->b_addr;
for(j=0; j<4; j++)
{
if(mbr->partitions[j].type==RDISK_SWAP)
{
// If this partition is the biggest so far
// then store it. We'll use this if
// there is no active partition.
if(mbr->partitions[j].lbalength>max_size)
{
max_size = mbr->partitions[j].lbalength;
bd = makedev(i,j+1);
}
// If it is active, then use it.
if(mbr->partitions[j].status & P_ACTIVE)
{
brelse(bp);
rdclose(makedev(i,0),0,0);
return makedev(i,j+1);
}
}
}
brelse(bp);
}
rdclose(makedev(i,0),0,0);
}
}
// There is no active partition, so we'll use the biggest one we found.
return bd;
#endif
}
dev_t get_boot_device()
{
// If a root device has been specified, then we can short cut all this and just
// use that device.
#ifdef ROOT
return ROOT;
#else
dev_t bd = -1;
int i,j,e;
struct buf *bp;
struct mbr *mbr;
for(i=0; i<NRDSK; i++)
{
e = rdopen(makedev(i,0),0,S_SILENT);
if(e==0)
{
bp = read_mbr(i);
if(bp)
{
mbr = (struct mbr *)bp->b_addr;
for(j=0; j<4; j++)
{
if(mbr->partitions[j].type==RDISK_FS)
{
if(mbr->partitions[j].status & P_ACTIVE)
{
brelse(bp);
rdclose(makedev(i,0),0,0);
return makedev(i,j+1);
}
}
}
brelse(bp);
}
rdclose(makedev(i,0),0,0);
}
}
return bd;
#endif
}
daddr_t rdsize(dev_t dev)
{
int root = major(dev);
if(root>MAXDEV) return ENODEV;
int part = minor(dev);
int unit = disks[root].unit;
unsigned int blocks;
if(part==0)
{
return disks[root].size(unit);
} else {
if(rdopen(dev,0,S_SILENT)!=0)
return 0;
blocks=dflags[root].len[part-1];
rdclose(dev,0,0);
DEBUG3("rd%d%c: get partition size: %d\n",root,part+'a'-1,blocks);
return blocks;
}
}
unsigned char partition_type(dev_t dev)
{
struct buf *bp;
struct mbr *mbr;
unsigned char pt;
if (minor(dev)<1 || minor(dev)>4)
return 0;
if (rdopen(dev,0,S_SILENT) == 0) {
bp = read_mbr(major(dev));
rdclose(dev, 0, 0);
if (! bp) {
brelse(bp);
return 0;
}
mbr = (struct mbr *)bp->b_addr;
pt = mbr->partitions[minor(dev)-1].type;
brelse(bp);
return pt;
}
return 0;
}
