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fixed problems in Storage module: caused integer overflow and bad pointers

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This commit is contained in:
ceriel 1988-04-11 10:34:31 +00:00
parent 48d2fa770e
commit d7030591f9
1 changed files with 17 additions and 12 deletions
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29
lang/m2/libm2/Storage.mod
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@ -35,7 +35,7 @@ IMPLEMENTATION MODULE Storage;
Bucket =
RECORD
CASE : BOOLEAN OF
FALSE: BSIZE: INTEGER; (* size of user part in UNITs *)
FALSE: BSIZE: CARDINAL; (* size of user part in UNITs *)
BNEXT: BucketPtr; | (* next free Bucket *)
TRUE: BXX: ALIGNTYPE
END;
@ -53,8 +53,8 @@ IMPLEMENTATION MODULE Storage;
USED: ADDRESS;
PROCEDURE MyAllocate(size: CARDINAL) : ADDRESS;
VAR nu : INTEGER;
b : INTEGER;
VAR nu : CARDINAL;
b : CARDINAL;
p, q: BucketPtr;
brk : ADDRESS;
BEGIN
@ -79,7 +79,7 @@ IMPLEMENTATION MODULE Storage;
IF FreeLists[b] # NIL THEN
q := FreeLists[b];
FreeLists[b] := q^.BNEXT;
p := ADDRESS(q) + CARDINAL((nu+1)*UNIT);
p := ADDRESS(q) + (nu+1)*UNIT;
(* p indicates the block that must be given
back
*)
@ -113,7 +113,7 @@ IMPLEMENTATION MODULE Storage;
(* split block,
tail goes to FreeLists area
*)
q := ADDRESS(p) + CARDINAL((nu+1)*UNIT);
q := ADDRESS(p) + (nu+1)*UNIT;
q^.BSIZE := p^.BSIZE -nu -1;
q^.BNEXT := FreeLists[q^.BSIZE];
FreeLists[q^.BSIZE] := q;
@ -124,7 +124,7 @@ IMPLEMENTATION MODULE Storage;
(* Give part of tail of original block.
Block stays in this list.
*)
q := ADDRESS(p) + CARDINAL((p^.BSIZE-nu)*UNIT);
q := ADDRESS(p) + (p^.BSIZE-nu)*UNIT;
q^.BSIZE := nu;
p^.BSIZE := p^.BSIZE - nu - 1;
q^.BNEXT := USED;
@ -202,8 +202,9 @@ IMPLEMENTATION MODULE Storage;
PROCEDURE ReOrganize();
VAR lastblock: BucketPtr;
b, be: BucketPtr;
i: INTEGER;
i: CARDINAL;
BEGIN
lastblock := NIL;
FOR i := 1 TO NLISTS DO
b := FreeLists[i];
WHILE b # NIL DO
@ -231,7 +232,7 @@ IMPLEMENTATION MODULE Storage;
b := FirstBlock;
WHILE ADDRESS(b) < ADDRESS(lastblock) DO
LOOP
be := ADDRESS(b)+CARDINAL((b^.BSIZE+1)*UNIT);
be := ADDRESS(b)+(b^.BSIZE+1)*UNIT;
IF b^.BNEXT # NIL THEN
(* this block is not free *)
EXIT;
@ -245,9 +246,13 @@ IMPLEMENTATION MODULE Storage;
EXIT;
END;
(* this block and the next one are free,
so merge them
so merge them, but only if it is not too big
*)
b^.BSIZE := b^.BSIZE + be^.BSIZE + 1;
IF MAX(CARDINAL) - b^.BSIZE > be^.BSIZE THEN
b^.BSIZE := b^.BSIZE + be^.BSIZE + 1;
ELSE
EXIT;
END;
END;
b := be;
END;
@ -270,12 +275,12 @@ IMPLEMENTATION MODULE Storage;
END;
END;
END;
b := ADDRESS(b) + CARDINAL((b^.BSIZE+1) * UNIT);
b := ADDRESS(b) + (b^.BSIZE+1) * UNIT;
END;
END ReOrganize;
PROCEDURE InitStorage();
VAR i: INTEGER;
VAR i: CARDINAL;
brk: ADDRESS;
BEGIN
FOR i := 1 TO NLISTS DO