1 files changed, 176 insertions, 0 deletions

diff --git a/v4.0/src/INC/MFT.INC b/v4.0/src/INC/MFT.INC
new file mode 100644
index 0000000..0359f80
--- /dev/null
+++ b/v4.0/src/INC/MFT.INC
@@ -0,0 +1,176 @@
+BREAK   <MFT Definitions>
+
+;**     MSDOS MFT definitions
+;
+;   The Master File Table (MFT) associates the cannonicalized pathnames, lock
+;   records and SFTs for all files open on this machine.
+;
+;   The MFT implementation employs a single memory buffer which is used from
+;   both ends.  This gives the effect (at least until they run into each
+;   other) of two independent buffers.
+;
+;       MFT buffer
+;       ==========
+;   The MFT buffer contains MFT name records and free space.  It uses a
+;   classic heap architecture:  freed name records are marked free and
+;   conglomerated with any adjacent free space.  When one is to create a name
+;   entry the free list is searched first-fit.  The list of name and free
+;   records is always terminated by a single END record.
+;
+;       LOCK buffer
+;       ===========
+;   The lock buffer contains fixed format records containing record locking
+;   information.  Since they are fixed format the space is handled as a series
+;   of chains:  one for each MFT name record and one for the free list.  No
+;   garbage collection is necessary.
+;
+;       Space allocation
+;       ================
+;   The MFT is managed as a heap.  Empty blocks are allocated on a first-fit
+;   basis.  If there is no single large enough empty block the list is garbage
+;   collected.
+;
+;       MFT name records:
+;
+;              8     16     8     16     32     16        n
+;           |------|-----|-----|------|------|------|---------~~~~~~---------|
+;           | FLAG | LEN | SUM | LPTR | SPTR | SERL |     <.asciz string>    |
+;           --------------------------------------------------~~~~~~----------
+;
+;                       FLAG = record type flag
+;                       LEN =  total byte length of record.
+;                       SUM =  sum of bytes in asciz string.  Used to speed
+;                              searches
+;                       LPTR=  pointer to first record in lock chain segment
+;                              is MFT segment
+;                       SPTR= pointer to first sft in sft chain
+;                       SERL= serial number
+;                       <string> = name string, zero-byte terminated.  There
+;                              may be garbage bytes following the 00 byte;
+;                              these are counted in the LEN field.
+;
+;
+;       MFT free records
+;
+;              8      16
+;           |------|-----|----~~~~~~~~~~~~~~~~~~~~~~~~~~~---------|
+;           | FLAG | LEN |         free                           |
+;           ------------------~~~~~~~~~~~~~~~~~~~~~~~~~~~----------
+;
+;                       FLAG = record type flag
+;                       LEN  = total byte length of record.
+;
+;
+;       MFT END records
+;
+;                  8
+;               |------|
+;               | FLAG |
+;               --------
+;
+;                       FLAG = record type flag
+
+;**     MFT definitions
+;*
+;*      NOTE:  the flag and length fields are identical for all record types
+;*              (except the END type has no length) This must remain so as
+;*              some code depends upon it.
+;*
+;*      NOTE:  Many routines check for "n-1" of the N flag values and if no
+;*              match is found assume the flag value must be the remaining
+;*              possibility.  If you add or remove flag values you must check
+;*              all references to mft_flag.
+
+MFT_entry       STRUC
+
+mft_flag        DB      ?               ; flag/len field
+mft_len         DW      ?
+mft_sum         DB      ?               ; string sum word
+mft_lptr        DW      ?               ; LCK pointer
+mft_sptr        DD      ?               ; sft pointer
+mft_serl        DW      ?               ; serial number
+mft_name        DB      ?               ; offset to start of name
+
+MFT_entry       ENDS
+
+MFLG_NAM        EQU     1               ; min value for name record
+MFLG_FRE        EQU     0               ; free record
+MFLG_END        EQU     -1              ; end record
+
+;*      Record Lock Record (RLR):
+;
+;                  16       32       32       32
+;               |-------|--------|--------|--------|
+;               | NEXT  |  FBA   |  LBA   |  SPTR  |
+;               |       | lo hi  | lo hi  |        |
+;               ------------|--------|--------------
+;
+;                       CHAIN  = pointer to next RLR.  0 if end
+;                       FBA    = offset of 1st  byte of locked region
+;                       LBA    = offset of last byte of locked region
+;                       SPTR   = pointer to SFT lock was issued on
+
+RLR_entry       STRUC
+
+rlr_next        DW      ?               ; chain to next RLR, 0 if end
+rlr_fba         DW      ?               ; first byte addr (offset) of reigion
+                DW      ?
+rlr_lba         DW      ?               ; last byte addr of region
+                DW      ?
+rlr_sptr        DD      ?               ; SFT pointer
+rlr_pid         dw      ?               ; process id of issuer
+rlr_type        dw      ?               ; lock type
+RLR_entry       ENDS
+
+rlr_lall        equ     00h            ; lock all ops
+rlr_lwr         equ     01h            ; lock write ops
+
+;
+;   A pictorial diagram for the linkages is as follows:
+;
+;          +---sptr------+
+;          V             |
+;        +---+<----------|---sptr------+------------+
+;        |SFT+----+      |             |            |
+;        +-+-+    |    +-+-+        +--+-+       +--+-+
+;          V      +--->|MFT+-lptr->-|LOCK+-next->|LOCK+->0
+;        +---+    |    +---+        +----+       +----+
+;        |SFT+----+      ^
+;        +-+-+           |
+;          |             |
+;          +-------------+
+;
+;
+
+;**
+;
+;   Interesting behavior should be noted:
+;
+;       The sharer must maintain information on files in three forms:
+;
+;       local/remote handles.  These are normal handles and behave in no
+;           strange manner.  They are identified by SF_mode not having the
+;           sfIsFCB flag nor by having the sf_mode = 70.  No problems with
+;           locking.  No problems with open.  No problems with close.
+;           CloseByName will iterate closes until the mft disappears.
+;           CloseUser will iterate closes until no SFT for the particular user
+;           appears.  CloseProcess will iterate closes until no SFT for the
+;           particular user/process appears.
+;
+;       local FCBs.  There are no corresponding SFT's for these as the SFTs
+;           are cached but will be valid for the particular file.  There is
+;           one SFT for each open on a file by a specific process.  These are
+;           identified the sfIsFCB flag in the sf_mode field.  When multiple
+;           opens occur, we merely find the sf pertinent to the file and
+;           process.  Close decrements the ref count.  CloseByName, CloseUser,
+;           CloseProcess will iterate closes until no more SFTs exist.
+;
+;       handles with mode 70.  These represent FCB's open across the network.
+;           As such, identical sfts may have been collapsed by the $open code.
+;           This results in a reuse of the same SFT.  The $Open code must
+;           correctly set the ref-count for the sft to reflect the number of
+;           collapses that have occurred.  These are identified by a 70 in the
+;           SF_mode field.  There can be no locking on these SFTs.  Open must
+;           scan the list of SFTs for the file and increment its ref count
+;           appropriately.
+
\ No newline at end of file