fix the default disk label

diskpart/lib/diskpart.lua

@@ -26,29 +26,55 @@ local function getProxy(addr)
  end
  return addr
 end
+local function aop(td,n,mn,...)
+ local rv
+ if td.getPosition then
+  local rts = td.getPosition()
+  if rts ~= n then
+   td.seek(n - rts)
+  end
+  rv = {td[mn](...)}
+--  td.seek(rts - n)
+ else
+  local rts = td.seek(-math.huge)
+  td.seek(n)
+  rv = {td[mn](...)}
+  td.seek(-math.huge)
+  td.seek(rts)
+ end
+ return table.unpack(rv)
+end
 
 function partition.getPartitions(drive)
  drive = getProxy(drive)
- local rv = partition.parse(drive.readSector(drive.getCapacity() / drive.getSectorSize()))
- return rv[1][2] == "mtpt" and rv or {}
+ local rv
+ if drive.type == "tape_drive" then
+  td = getProxy(td)
+  local ts = drive.getSize()
+  local lso = (math.floor(ts / 512) - 1) * 512
+  rv = partition.parse(aop(drive, lso, "read", ts - lso))
+ else
+  rv = partition.parse(drive.readSector(drive.getCapacity() / drive.getSectorSize()))
+ end
+ return #rv > 0 and rv[1][2] == "mtpt" and rv or {}
 end
 function partition.setPartitions(drive, pt, name)
  drive = getProxy(drive)
- name = name or ""
- if pt[1][2] ~= "mtpt" then table.insert(pt, 1, {name, "mtpt", 0, 0}) end
+ if pt[1][2] ~= "mtpt" then table.insert(pt, 1, {name or drive.address:sub(1,8), "mtpt", 0, 0}) end
  local ns = partition.generate(pt)
+ if drive.type == "tape_drive" then
+  local ts = drive.getSize()
+  local lso = (math.floor(ts / 512) - 1) * 512
+  return aop(drive, lso, "write", partition.generate(pt) .. ("\0"):rep(ts - lso))
+ end
  return drive.writeSector(drive.getCapacity() / drive.getSectorSize(), ns .. ("\0"):rep(drive.getSectorSize() - #ns))
 end
 
 function partition.proxyPartition(drive, index)
  drive = getProxy(drive)
  local part = partition.getPartitions(drive)[index]
- local sectorOffset, byteOffset, finish = part[3] - 1, (part[3]-1) * drive.getSectorSize()
- local proxy = {label=part[1],ptype=part[2]}
+ local proxy = {label=part[1],ptype=part[2],address=drive.address.."/"..tostring(index),type="partition"}
 
- function proxy.getCapacity()
-  return drive.getSectorSize() * part[4]
- end
  function proxy.getLabel()
   return part[1]
  end
@@ -56,6 +82,41 @@ function partition.proxyPartition(drive, index)
   return false
  end
 
+ if drive.type == "tape_drive" then
+  local start, len, bs= part[3]-1, part[4], 512
+  local proxy = {}
+  local function checkBounds(n)
+   if n < 0 or n > len * bs then
+    error("out of bounds")
+   end
+   return (start * bs) + n
+  end
+  function proxy.readSector(n)
+   return aop(drive, checkBounds((n-1) * bs), "read", bs)
+  end
+  function proxy.writeSector(n,d)
+   return aop(drive, checkBounds((n-1) * bs), "write", d .. ("\0"):rep(512-#d))
+  end
+  function proxy.readByte(n)
+   return aop(drive, checkBounds(n-1), "read")
+  end
+  function proxy.writeByte(n,d)
+   return aop(drive, checkBounds(n-1), "write",d)
+  end
+  function proxy.getSectorSize()
+   return bs
+  end
+  function proxy.getCapacity()
+   return len * 512
+  end
+  return proxy
+ end
+
+ local sectorOffset, byteOffset = part[3] - 1, (part[3]-1) * drive.getSectorSize()
+ function proxy.getCapacity()
+  return drive.getSectorSize() * part[4]
+ end
+
  local function offsetSector(sector)
   if sector < 1 or sector > part[4] then error("invalid offset, not in a usable sector") end
   return sectorOffset + sector