DIRECTORY
Basics USING [ShortNumber, LongNumber],
MoberyPrivate,
IO,
Rope,
UXStrings, UnixTypes;

MoberyObjectFileImpl: CEDAR PROGRAM
IMPORTS IO, MoberyPrivate, Rope, UXStrings
~ BEGIN

ROPE: TYPE = Rope.ROPE;


aoutHeaderBytes: INT = 4+4*7; -- size of header for a.out .o files
aoutTextSizeOffset: INT = 4; -- byte offset of text size field in a.out .o files
aoutMagicOffset: INT = 2; -- byte offset of magic number in a.out .o files


xcoffMagicOffset: INT = 0; -- byte offset of magic number in xcoff files
xcoffHeaderBytes: INT = 4+4*3+4; -- size of header for xcoff filehdr
xcoffOptionalHdrSizeOffset: INT = 16; -- offset of optional header (aouthdr) size in filehdr
xcoffScnHdrSectionNameOffset: INT = 0; -- byte offset of section name field within xcoff scn
xcoffScnHdrSectionStartOffset: INT = 8; -- byte offset of section start offset within xcoff scn
xcoffScnHdrSize: INT = 40; -- size of xcoff section header
xcoffScnNameLen: INT = 8; -- size of xcoff section name
xcoffDataSectionName: ROPE = ".data";

ReadBinaryShort: PROC [s: IO.STREAM] RETURNS [INT16] ~ {
sn: Basics.ShortNumber _ [si[0]];
sn.hi _ IO.GetByte[s];
sn.lo _ IO.GetByte[s];
RETURN [sn.sc];
};

ReadBinaryINT: PROC [stream: IO.STREAM] RETURNS [INT] ~ {
ln: Basics.LongNumber _ [li[0]];
ln.hh _ IO.GetByte[stream];
ln.hl _ IO.GetByte[stream];
ln.lh _ IO.GetByte[stream];
ln.ll _ IO.GetByte[stream];
RETURN [ln.li]
};

ReadBinaryUINT: PROC [stream: IO.STREAM] RETURNS [CARD] ~ {
ln: Basics.LongNumber _ [lc[0]];
ln.hh _ IO.GetByte[stream];
ln.hl _ IO.GetByte[stream];
ln.lh _ IO.GetByte[stream];
ln.ll _ IO.GetByte[stream];
RETURN [ln.lc]
};


MoberyXCoffTester: MoberyPrivate.ObjectFileTypeMatcherProc ~ {
magicNumber, numOfSections, optHdrLength: INT;

isXCoff: PROC[num: INT] RETURNS [BOOLEAN] = INLINE {
RETURN [num = 0730B OR num = 0735B OR num = 0737B OR num = 6201H OR num = 0160H];
};
readSectionName: PROC [s: IO.STREAM] RETURNS [REF TEXT] ~ {
b: REF TEXT = NEW[TEXT[xcoffScnNameLen]];
[] _ IO.GetBlock[self: s, block: b, count: xcoffScnNameLen];
RETURN [b];
};

IF NOT stream.EndOf[] THEN {
IO.SetIndex[self: stream, index: xcoffMagicOffset];
magicNumber _ ReadBinaryShort[stream];
IF isXCoff[magicNumber]  THEN {
matches _ TRUE;
numOfSections _ ReadBinaryShort[stream]; -- read number of sections
IO.SetIndex[self: stream, index: xcoffOptionalHdrSizeOffset];
optHdrLength _ ReadBinaryShort[stream]; -- get length of optional header (a.out)
IO.SetIndex[stream, IO.GetIndex[self: stream] - 2 + optHdrLength + (xcoffHeaderBytes - xcoffOptionalHdrSizeOffset)];
WHILE (numOfSections > 0) DO
scnName: REF TEXT;
scnName _ readSectionName[stream];
IF Rope.EqualSubstrs[s1: xcoffDataSectionName, len1: xcoffDataSectionName.Length[], s2: Rope.FromRefText[s: scnName], len2: xcoffDataSectionName.Length[]] THEN {
size: CARD;
[] _ ReadBinaryUINT[stream]; -- skip physical address field
[] _ ReadBinaryUINT[stream]; -- skip virtual address field
size _ ReadBinaryUINT[stream];
start _ ReadBinaryUINT[stream];
end _ start + size;
EXIT;
};
numOfSections _ numOfSections - 1;
IO.SetIndex[stream, IO.GetIndex[stream] - xcoffScnNameLen + xcoffScnHdrSize]; -- advance to next section header
ENDLOOP;
IF (numOfSections <= 0) OR (NOT start IN [0..end) AND end <= IO.GetLength[stream]) THEN {
start _ 0;
end _ IO.GetLength[stream];
};
};
};
};

MoberyADotOutTester: MoberyPrivate.ObjectFileTypeMatcherProc ~ {
magicNumber: INT;

isADotOut: PROC[num: INT] RETURNS [BOOLEAN] = INLINE {
RETURN [num = 0407B OR num = 0410B OR num = 0413B];
};

IO.SetIndex[self: stream, index: aoutMagicOffset];
IF NOT stream.EndOf[] THEN {
magicNumber _ ReadBinaryShort[stream];
IF isADotOut[magicNumber] THEN {
matches _ TRUE;
IO.SetIndex[self: stream, index: aoutTextSizeOffset];
start _ aoutHeaderBytes + ReadBinaryINT[stream];
end _ start + ReadBinaryINT[stream];
IF NOT start IN [0..end) AND end <= IO.GetLength[stream] THEN {
start _ 0;
end _ IO.GetLength[stream];
};
};
};
};

MoberyPrivate.RegisterObjectFileType[MoberyADotOutTester];
MoberyPrivate.RegisterObjectFileType[MoberyXCoffTester];

END.
   –  
MoberyObjectFileImpl.mesa
Mna, May 3, 1992 4:27 pm PDT

IO USING [EndOf, GetBlock, GetByte, GetIndex, GetLength, SetIndex, STREAM],
a.out portions of this file created from MoberyImpl.mesa.

a.out know-how (thanks to Michael Plass) 
XCOFF know-how (thanks to IBM documentation)
This routine handles both XCOFF (AIX) and ECOFF (DEC/MIPS/SGI) as the differences in the object file formats between ECOFF and XCOFF are not large enough to affect the stamp-finding algorithm. 
PROC[stream: IO.STREAM] RETURNS [matches: BOOLEAN _ FALSE, start, end: CARD]
isXCoff also checks if the binary is a valid dec ECOFF executable.  
an object file.
seek to section headers at end of optional a.out header
find data section section and determine where to search for stamps
confusion! search whole file.
PROC[stream: IO.STREAM] RETURNS [matches: BOOLEAN _ FALSE, start, end: CARD]
an object file.
confusion! search whole file.
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