컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Appendix D OS/2 Load Module Format OS/2 programs, dynlink libraries, and device drivers reside on the disk in load modules called segmented executable files, or "new EXE" files. The new EXE file format, which is also used by Microsoft Windows, is a superset of the "old EXE" format used by MS-DOS. Components of a Segmented Executable File A segmented EXE file is composed of many distinct but interrelated elements, as shown in Figure D-1 on the following page. A hex dump of a simple OS/2 program (the PORTS.EXE file from Chapter 14) is shown in Figure D-2, beginning on p. 717, with the various elements of the file marked. You can use the Microsoft utility program EXEHDR.EXE to display much of the information described in this section for any specific OS/2 program, library, or driver. Throughout the remainder of this appendix, the term counted string is used to refer to a string that consists of a length byte followed by the ASCII characters of the actual string. The value of the length byte does not include the length byte itself, and the string is not terminated by a null byte. 旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Old EXE header � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � MS-DOS stub program � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � New EXE header � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Segment table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Resource table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Resident names table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Module reference table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Imported names table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Entry table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Nonresident names table � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 컴컴캑 � Segment #1 code or data � � Segment #1 relocation information � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 컨� 컨� 컫� 컫� 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Segment #n code or data � � Segment #n relocation information � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � � � Resources � � � 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Figure D-1. Block diagram of a file containing an OS/2 program, dynlink library, or device driver. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 0 1 2 3 4 5 6 7 8 9 A B C D E F 旼0000 4D 5A 5E 00 04 00 00 00 04 00 00 00 FF FF 00 00 MZ^............. Old EXE캑 0010 B8 00 00 00 00 00 00 00 40 00 00 00 00 00 00 00 ........@....... header � 0020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 읕0030 00 00 00 00 00 00 00 00 00 00 00 00 80 00 00 00 ................ 旼0040 0E 1F BA 0E 00 B4 09 CD 21 B8 01 4C CD 21 54 68 ........!..L.!Th MS-DOS캑 0050 69 73 20 70 72 6F 67 72 61 6D 20 63 61 6E 6E 6F is program canno stub program � 0060 74 20 62 65 20 72 75 6E 20 69 6E 20 44 4F 53 20 t be run in DOS 읕0070 6D 6F 64 65 2E 0D 0A 24 00 00 00 00 00 00 00 00 mode...$........ 旼0080 4E 45 05 01 7D 00 12 00 19 6A 56 F8 0A 02 03 00 NE..}....jV..... New EXE캑 0090 00 00 00 10 00 00 02 00 00 00 03 00 03 00 01 00 ................ header � 00A0 0D 00 40 00 58 00 58 00 71 00 73 00 0F 01 00 00 ..@.X.X.q.s..... 읕00B0 02 00 09 00 00 00 01 00 00 00 00 00 00 00 00 00 ................ Segment 旼00C0 01 00 20 00 10 08 21 00 02 00 C1 00 00 0D C1 00 .. ...!......... table컨�00D0 03 00 5E 00 01 0C 5E 00 ..^...^. Resident 旼 05 50 4F 52 54 53 00 00 .PORTS.. names캑 00E0 05 52 50 4F 52 54 01 00 05 57 50 4F 52 54 02 00 .RPORT...WPORT.. table 읕00F0 00 . Module reference컴컴컴컴컴컴01 00 .. table Imported names컴컴컴컴컴컴컴컴컴00 08 44 4F 53 43 41 4C 4C 53 ..DOSCALLS table Entry 旼 02 FF 09 ... table컨�0100 CD 3F 01 00 00 11 CD 3F 01 0F 00 01 00 00 00 .?.....?....... Nonresident names 旼 09 . table컨�0110 50 4F 52 54 53 2E 45 58 45 00 00 00 PORTS.EXE... 旼 00 00 00 00 .... � 0120 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ � . Filler bytes캑 . � . 읕01F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Code segment 旼0200 55 8B EC 52 8B 56 06 EC 32 E4 5A 5D CA 02 00 55 U..R.V..2.Z]...U (IO_TEXT)컨�0210 8B EC 50 52 8B 46 06 8B 56 08 EE 5A 58 5D CA 04 ..PR.F..V..ZX].. 旼0220 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ � . Filler bytes캑 . � . 읕03F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 旼0400 1E 07 6A 00 6A 00 6A 00 68 FF 00 9A FF FF 00 00 ..j.j.j.h....... � . Code segment � . (_TEXT)캑 . � 04B0 AA 8A C4 E8 02 00 AA C3 04 30 3C 39 7E 02 04 07 .........0<9~... 읕04C0 C3 旼 04 00 03 01 98 00 01 00 05 00 03 01 7A 00 01 .............z.. Relocation table캑 04D0 00 8A 00 03 01 8F 00 01 00 45 00 03 00 63 00 FF .........E...c.. for _TEXT 읕04E0 00 01 00 ... 旼 00 00 00 00 00 00 00 00 00 00 00 00 00 ............. � 04F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ � . Filler bytes캑 . � . 읕05F0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 旼0600 00 00 0D 0A 44 6F 73 50 6F 72 74 41 63 63 65 73 ....DosPortAcces � . Data segment캑 . (_DATA) � . 읕0650 20 20 46 0D 0A 4E 4E 4E 4E 20 20 20 4E 4E F..NNNN NN 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Figure D-2. Simple segmented executable file (the PORTS.EXE program from Chapter 14). Note that this program has no resource table nor any resources at the end of the file. Old EXE Header The format of the "old EXE" header is shown in Figure D-3. The most important parts of this header are the familiar MS-DOS signature ("MZ") for a relocatable executable file, the value 0040H at offset 0018H, which is the offset of the MS-DOS stub program and which also signals the existence of a "new EXE" header, and the 32-bit offset to the "new EXE" header at offset 003CH. 00H 旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Signature byte 1 `M' � 01H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Signature byte 2 `Z' � 02H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Length of file header and � � program image MOD 512 � 04H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Length of file header and program � � image in 512-byte pages � 06H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Number of relocation table � � items for MS-DOS stub program � 08H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Size of old EXE header in paragraphs � 0AH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Minimum paragraphs of extra memory needed � � for execution of MS-DOS stub program � 0CH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Maximum paragraphs of extra memory needed � � for execution of MS-DOS stub program � 0EH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Segment displacement of stub program stack � 10H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Contents of SP register at stub program entry � 12H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Checksum � 14H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Contents of IP register at stub program entry � 16H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Segment displacement of stub program code � 18H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � File offset of first stub program relocation � � item (0040H indicates segmented file present) � 1AH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � Overlay number (0) � 1CH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � � � Reserved � � � 24H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � OEM identifier � 26H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � OEM information � 28H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � � � Reserved � � � 3CH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � � � File offset of new EXE header � 40H 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Figure D-3. Old EXE header at the beginning of an OS/2 executable file. MS-DOS Stub Program The MS-DOS stub program, which is executed if the EXE file is loaded in real mode under MS-DOS or in DOS compatibility mode under OS/2, always begins at offset 0040H in the file. If you do not explicitly specify a stub program in the DEF file when you link the OS/2 program, the Linker inserts a program that displays an error message and terminates. The stub program has its own relocation table and can be of any size. The entry point, stack size, and the locations of the relocation table, code, and data for the stub program are specified in the old EXE header. When a program is "bound" for use as a Family application, the BIND utility replaces the original stub program with a "real mode loader" and an additional routine for each OS/2 API function that the program uses. When the bound program is run, the real mode loader gains control, performs all necessary relocations, and patches each API function call to point to a routine that translates the parameters on the stack into the appropriate parameters in registers and executes a software interrupt. New EXE Header The new EXE header is much more complicated than the old EXE header. The fields of the new EXE header are shown in Figure D-4. Some header fields are set by DEF file directives and describe the characteristics and behavior of a program or library, as well as the initial size of the stack and local heap. The remaining fields specify the locations and sizes of other file elements such as the resident and nonresident names tables and the segment table. (The actual code and data segments are described in the segment table rather than in the new EXE header.) A critical field in the new EXE header is the file alignment unit size at offset 32H. This size is expressed as a power of 2; for example, the value 9 represents a file unit size of 512 bytes. Each component of an executable file (except for resources) begins at an offset within the file that is a multiple of the alignment unit size, and many of the tables within the file express locations and sizes in multiples of this unit. 00H 旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴커 � Signature byte 1 `N' � 01H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Signature byte 2 `E' � 02H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Linker major version number � 03H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Linker minor version number � 04H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Offset of entry table � � (relative to start of new EXE header) � 06H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Length of entry table � 08H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � 32-bit CRC of entire file � 0CH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Module flags 쳐컴컴 0EH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Segment number of DGROUP � 10H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Initial size of local heap � 12H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Initial size of thread 1 stack � 14H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Contents of IP register at program entry � 16H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Segment number containing entry point � 18H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Contents of SP register at program entry � 1AH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Segment number containing thread 1 stack � 1CH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Entries in segment table � 1EH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Entries in module reference table � 20H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Length of nonresident names table � 22H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑커 � Offset of segment table � � 24H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � � Offset of resource table � � 26H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � � Offset of resident names table � 쳐컴 28H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � � Offset of module ref. table � � 2AH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � � Offset of imported names table � � 2CH 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑켸 � Offset of nonresident names table 쳐컴컴 30H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Number of movable entry points � 32H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Size of file alignment unit (power of 2) � 34H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Number of resource table entries � 36H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � Target operating system 쳐컴컴 37H 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴캑 � � � Reserved � � � 40H 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴켸 Figure D-4. New EXE header, which follows the MS-DOS훏ompatible stub program in an OS/2 executable file. Segment Table The segment table describes the size, location within the file, and characteristics of each of the program's code and data segments. This table is read into memory by the OS/2 loader; it remains resident as long as the program or library is in use so that the loader can quickly locate discardable or load-on-demand code and data segments within the file. Each entry in the table is 8 bytes long and has the following format: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 2 Offset of beginning of segment within file (expressed as multiple of file unit size) 02H 2 Length of segment (0 = 65,536 bytes) 04H 2 Segment flags Bit(s) Significance 0�2 Segment type 0 = code 1 = data 3 0 = noniterated data 1 = iterated data 4 0 = fixed 1 = movable 5 0 = impure or nonshareable 1 = pure or shareable 6 0 = load-on-call 1 = preload 7 0 = execute/read if code, read/write if data 1 = execute-only if code, read-only if data 8 0 = no relocation table 1 = relocation table present 9 0 = nonconforming 1 = conforming 10�11 Privilege level 12 0 = nondiscardable 1 = discardable 13 0 = 16-bit code segment 1 = 32-bit code segment 14 0 = normal segment 1 = huge segment 15 Reserved 06H 2 Minimum allocation size for segment (0 = 65,536 bytes) 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 When other tables refer to segments, they use a one-based number that corresponds to an entry in the segment table. Resource Table The resource table is used in Presentation Manager applications to specify the size, location, and type of resources at the end of the file. The table starts with a 16-bit resource shift count: a power of 2 which defines the resource unit size. (Resources can use a different unit size than the one specified in the new EXE header for all other elements of the file.) The resource shift count is followed by two or more resource type headers, each header followed by resource entries that define the location, size, and characteristics of the associated resources. The end of the main portion of the resource table is indicated by a resource type header with a zero byte in the resource type position. Resource type headers have the following format: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 2 Resource type identifier (if bit 15 = 1) or offset to type string (if bit 15 = 0) 02H 2 Number of resources for this type 04H 4 Reserved 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Each resource entry is formatted as follows: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 2 Offset of resource within file (as multiple of resource unit size) 02H 2 Length of resource (as multiple of resource unit size) 04H 2 Resource flags Bit(s) Significance 0�3 Reserved 4 0 = fixed 1 = movable 5 0 = impure or nonshareable 1 = pure or shareable 6 0 = load-on-call 1 = preload 7�11 Reserved 12�15 Discard priority 06H 2 Resource number (if bit 15 = 1) or offset to name string if bit 15 = 0) 08H 4 Reserved 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 When resources and their types are identified with names rather than numbers, the names are stored as a series of counted strings at the end of the resource table (after the zero byte indicating that there are no more resource type headers). The offsets to a name or type string in a resource type header or resource entry are relative to the beginning of the resource table itself. The end of the block of strings is indicated by a single zero byte. Resident Names Table The resident names table lists all the entry points in the program or dynlink library (defined with EXPORTS statements in the DEF file) that were not assigned ordinal numbers. Each entry in the table is a counted string followed by a one-based index to the entry table. The end of the resident names table is indicated by an entry consisting of a single zero byte. The first entry in the resident names table is the module name and has an entry table index of zero. Module Reference Table The module reference table consists of a series of word-size (16-bit) entries. Each entry is the offset of a module name in the imported names table. The number of entries in the module reference table컴that is, the total number of modules from which functions are imported컴is found at offset 1EH in the new EXE header. Imported Names Table Each entry in the imported names table is a counted string that names an imported function or a module that contains imported functions. Imported functions are dynamically linked at load time. The offset of the beginning of each module name is given by the corresponding word in the module reference table. The offsets of function names are found within relocation records. Entry Table The entry table defines the segment, offset, and type of each entry point within the EXE file. The entry points are bundled together by segment, the number of bundles in the entry table varying from one bundle to many. Each bundle begins with two bytes. The first byte contains the number of entry point records in the bundle; the second byte contains FFH if the segment is movable or the segment number if the segment is fixed. When a bundle describes a movable segment (the usual case in an OS/2 application), the remainder of the bundle is one or more 6-byte entries in the following format: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 1 Entry point flags Bit(s) Significance 0 0 = entry point not exported 1 = entry point exported 1 0 = entry point uses instance data 1 = entry point uses single data 2 Reserved 3�7 Number of stack parameter words 01H 2 Int 3FH instruction (CDH 3FH) 03H 1 Segment number of entry point 04H 2 Offset of entry point within segment 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 The entries in bundles for fixed segments are 3 bytes long and have the following format: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 1 Entry point flags (See above) 01H 2 Offset of entry point within segment 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 When the loader must locate an entry point by its ordinal number, it first scans all the bundles in the entry table until it finds one with the appropriate segment number. It then multiplies the ordinal number by the appropriate size (3 or 6) and uses the result as an index into the bundle. Nonresident Names Table The nonresident names table lists all the entry points in the program or dynlink library (defined with EXPORTS statements in the DEF file) that were assigned explicit ordinal numbers. Each entry in the table is a counted string followed by a one-based index to the entry table. The end of the table is indicated by an entry consisting of a single zero byte. The first entry in the nonresident names table is either the description string specified in the DEF file or the filename if the DEF file contains no description string; the first entry has an entry table index of zero. Code and Data Segments The beginning of each code segment and data segment is aligned within the file as specified by the field at offset 32H in the new EXE header. A segment may be iterated data or noniterated data, as indicated by the field at offset 04H in the corresponding entry in the segment table. Iterated segments take the following form: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 2 Number of iterations 02H 2 Bytes per iteration (n) 04H n Actual data for each iteration 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 The size of a noniterated segment is specified by the field at offset 02H in the corresponding segment table entry. If the segment table indicates that a segment has relocation information, the segment's code or data is followed immediately by a 16-bit value for the number of relocation items and then by one or more 8-byte entries for each relocation item. The format for this 8-byte entry depends on the type of relocation item it represents컴the three types found in normal applications are internal references, imported ordinals, and imported names. The format for an internal reference relocation entry, that is, a reference to another segment in the same executable file, has the following form: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 1 Type of relocation 0 = 8-bit offset 2 = 16-bit segment 3 = 32-bit far pointer 5 = 16-bit offset 11 = 48-bit far pointer 13 = 32-bit offset 01H 1 0 or 4 (indicates internal reference) 02H 2 Offset of relocation item within segment 04H 1 FFH if movable segment or number of fixed segment 05H 1 Reserved (0) 06H 2 Ordinal of entry point if segment movable, otherwise offset of entry point within its segment 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 The format for an imported ordinal relocation entry, that is, a reference to an entry point in another module which is being imported by ordinal number, has the following form: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 1 Type of relocation (See above) 01H 1 1 or 5 (indicates imported ordinal) 02H 2 Offset of relocation item within segment 04H 2 One-based index to module reference table 06H 2 Function ordinal number 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 The format for an imported name relocation entry, that is, a reference to an entry point in another module which is being imported by name, has the following form: Offset Length Description 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 00H 1 Type of relocation (See above) 01H 1 2 or 6 (indicates imported name) 02H 2 Offset of relocation item within segment 04H 2 One-based index to module reference table 06H 2 Offset to name of imported function in imported names table 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 If bit 2 of the byte at offset 01H in a relocation entry is set, the address or value of the external reference is to be added to the contents of the address in the target segment. Otherwise, the address in the target segment contains the offset of the next location in the target segment that requires the same relocation; in other words, all the locations that should be replaced with the same address or value are chained together. The end of the chain is indicated by a -1. Resources Resources are static data blocks such as icons, cursors, menus, and bitmaps that are bound into the executable file for a Presentation Manager application with the Resource Compiler (RC.EXE). Each resource has a name and a type, which can be represented either as a binary 16-bit value or as an ASCII string. The combination of the name and type is unique for each resource in a particular executable file. A Kernel application can (but seldom does) contain resources. It can load and obtain a selector for a specific resource with the API function DosGetResource. The NEWEXE.H Header File The C header file NEWEXE.H (Figure D-5 on the following pages) defines the load module and is the ultimate recourse when you need information about the format. Using the #include directive, you can include this header in C programs that must access EXE or DLL files. 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 /* * NEWEXE.H (C) Copyright Microsoft Corp 1984-1987 * * Data structure definitions for the OS/2 & Windows * executable file format. */ #define EMAGIC 0x5A4D /* Old magic number */ #define ENEWEXE sizeof(struct exe_hdr) /* Value of E_LFARLC for new .EXEs */ #define ENEWHDR 0x003C /* Offset in old hdr. of ptr. to new */ #define ERESWDS 0x0010 /* No. of reserved words (OLD) */ #define ERES1WDS 0x0004 /* No. of reserved words in e_res */ #define ERES2WDS 0x000A /* No. of reserved words in e_res2 */ #define ECP 0x0004 /* Offset in struct of E_CP */ #define ECBLP 0x0002 /* Offset in struct of E_CBLP */ #define EMINALLOC 0x000A /* Offset in struct of E_MINALLOC */ struct exe_hdr /* DOS 1, 2, 3 .EXE header */ { unsigned short e_magic; /* Magic number */ unsigned short e_cblp; /* Bytes on last page of file */ unsigned short e_cp; /* Pages in file */ unsigned short e_crlc; /* Relocations */ unsigned short e_cparhdr; /* Size of header in paragraphs */ unsigned short e_minalloc; /* Minimum extra paragraphs needed */ unsigned short e_maxalloc; /* Maximum extra paragraphs needed */ unsigned short e_ss; /* Initial (relative) SS value */ unsigned short e_sp; /* Initial SP value */ unsigned short e_csum; /* Checksum */ unsigned short e_ip; /* Initial IP value */ unsigned short e_cs; /* Initial (relative) CS value */ unsigned short e_lfarlc; /* File address of relocation table */ unsigned short e_ovno; /* Overlay number */ unsigned short e_res[ERES1WDS];/* Reserved words */ unsigned short e_oemid; /* OEM identifier (for e_oeminfo) */ unsigned short e_oeminfo; /* OEM information; e_oemid specific */ unsigned short e_res2[ERES2WDS];/* Reserved words */ long e_lfanew; /* File address of new exe header */ }; #define E_MAGIC(x) (x).e_magic #define E_CBLP(x) (x).e_cblp #define E_CP(x) (x).e_cp #define E_CRLC(x) (x).e_crlc #define E_CPARHDR(x) (x).e_cparhdr #define E_MINALLOC(x) (x).e_minalloc #define E_MAXALLOC(x) (x).e_maxalloc #define E_SS(x) (x).e_ss #define E_SP(x) (x).e_sp #define E_CSUM(x) (x).e_csum #define E_IP(x) (x).e_ip #define E_CS(x) (x).e_cs #define E_LFARLC(x) (x).e_lfarlc #define E_OVNO(x) (x).e_ovno #define E_RES(x) (x).e_res #define E_OEMID(x) (x).e_oemid #define E_OEMINFO(x) (x).e_oeminfo #define E_RES2(x) (x).e_res2 #define E_LFANEW(x) (x).e_lfanew #define NEMAGIC 0x454E /* New magic number */ #define NERESBYTES 9 /* Nine bytes reserved (now) */ #define NECRC 8 /* Offset into new header of NE_CRC */ struct new_exe /* New .EXE header */ { unsigned short ne_magic; /* Magic number NE_MAGIC */ unsigned char ne_ver; /* Version number */ unsigned char ne_rev; /* Revision number */ unsigned short ne_enttab; /* Offset of Entry Table */ unsigned short ne_cbenttab; /* Number of bytes in Entry Table */ long ne_crc; /* Checksum of whole file */ unsigned short ne_flags; /* Flag word */ unsigned short ne_autodata; /* Automatic data segment number */ unsigned short ne_heap; /* Initial heap allocation */ unsigned short ne_stack; /* Initial stack allocation */ long ne_csip; /* Initial CS:IP setting */ long ne_sssp; /* Initial SS:SP setting */ unsigned short ne_cseg; /* Count of file segments */ unsigned short ne_cmod; /* Entries in Module Reference Table */ unsigned short ne_cbnrestab; /* Size of non-resident name table */ unsigned short ne_segtab; /* Offset of Segment Table */ unsigned short ne_rsrctab; /* Offset of Resource Table */ unsigned short ne_restab; /* Offset of resident name table */ unsigned short ne_modtab; /* Offset of Module Reference Table */ unsigned short ne_imptab; /* Offset of Imported Names Table */ long ne_nrestab; /* Offset of Non-resident Names Table */ unsigned short ne_cmovent; /* Count of movable entries */ unsigned short ne_align; /* Segment alignment shift count */ unsigned short ne_cres; /* Count of resource entries */ unsigned char ne_exetyp; /* Target operating system */ char ne_res[NERESBYTES]; /* Pad structure to 64 bytes */ }; #define NE_MAGIC(x) (x).ne_magic #define NE_VER(x) (x).ne_ver #define NE_REV(x) (x).ne_rev #define NE_ENTTAB(x) (x).ne_enttab #define NE_CBENTTAB(x) (x).ne_cbenttab #define NE_CRC(x) (x).ne_crc #define NE_FLAGS(x) (x).ne_flags #define NE_AUTODATA(x) (x).ne_autodata #define NE_HEAP(x) (x).ne_heap #define NE_STACK(x) (x).ne_stack #define NE_CSIP(x) (x).ne_csip #define NE_SSSP(x) (x).ne_sssp #define NE_CSEG(x) (x).ne_cseg #define NE_CMOD(x) (x).ne_cmod #define NE_CBNRESTAB(x) (x).ne_cbnrestab #define NE_SEGTAB(x) (x).ne_segtab #define NE_RSRCTAB(x) (x).ne_rsrctab #define NE_RESTAB(x) (x).ne_restab #define NE_MODTAB(x) (x).ne_modtab #define NE_IMPTAB(x) (x).ne_imptab #define NE_NRESTAB(x) (x).ne_nrestab #define NE_CMOVENT(x) (x).ne_cmovent #define NE_ALIGN(x) (x).ne_align #define NE_CRES(x) (x).ne_cres #define NE_RES(x) (x).ne_res #define NE_EXETYP(x) (x).ne_exetyp #define NE_USAGE(x) (WORD)*((WORD *)(x)+1) #define NE_PNEXTEXE(x) (WORD)(x).ne_cbenttab #define NE_ONEWEXE(x) (WORD)(x).ne_crc #define NE_PFILEINFO(x) (WORD)((DWORD)(x).ne_crc >> 16) /* * Target operating systems */ #define NE_UNKNOWN 0x0 /* Unknown (any "new-format" OS) */ #define NE_OS2 0x1 /* Microsoft/IBM OS/2 (default) */ #define NE_WINDOWS 0x2 /* Microsoft Windows */ #define NE_DOS4 0x3 /* Microsoft MS-DOS 4.x */ /* * Format of NE_FLAGS(x): * * p Not-a-process * x Unused * e Errors in image * x Unused * b Bound as family app * ttt Application type * f Floating-point instructions * 3 386 instructions * 2 286 instructions * 0 8086 instructions * P Protected mode only * p Per-process library initialization * i Instance data * s Solo data */ #define NENOTP 0x8000 /* Not a process */ #define NEIERR 0x2000 /* Errors in image */ #define NEBOUND 0x0800 /* Bound as family app */ #define NEAPPTYP 0x0700 /* Application type mask */ #define NENOTWINCOMPAT 0x0100 /* Not compatible with P.M. Windowing */ #define NEWINCOMPAT 0x0200 /* Compatible with P.M. Windowing */ #define NEWINAPI 0x0300 /* Uses P.M. Windowing API */ #define NEFLTP 0x0080 /* Floating-point instructions */ #define NEI386 0x0040 /* 386 instructions */ #define NEI286 0x0020 /* 286 instructions */ #define NEI086 0x0010 /* 8086 instructions */ #define NEPROT 0x0008 /* Runs in protected mode only */ #define NEPPLI 0x0004 /* Per-Process Library Initialization */ #define NEINST 0x0002 /* Instance data */ #define NESOLO 0x0001 /* Solo data */ struct new_seg /* New .EXE segment table entry */ { unsigned short ns_sector; /* File sector of start of segment */ unsigned short ns_cbseg; /* Number of bytes in file */ unsigned short ns_flags; /* Attribute flags */ unsigned short ns_minalloc; /* Minimum allocation in bytes */ }; #define NS_SECTOR(x) (x).ns_sector #define NS_CBSEG(x) (x).ns_cbseg #define NS_FLAGS(x) (x).ns_flags #define NS_MINALLOC(x) (x).ns_minalloc /* * * x Unused * h Huge segment * c 32-bit code segment * d Discardable segment * DD I/O privilege level (286 DPL bits) * c Conforming segment * r Segment has relocations * e Execute/read only * p Preload segment * P Pure segment * m Movable segment * i Iterated segment * ttt Segment type */ #define NSTYPE 0x0007 /* Segment type mask */ #define NSCODE 0x0000 /* Code segment */ #define NSDATA 0x0001 /* Data segment */ #define NSITER 0x0008 /* Iterated segment flag */ #define NSMOVE 0x0010 /* Movable segment flag */ #define NSSHARED 0x0020 /* Shared segment flag */ #define NSPRELOAD 0x0040 /* Preload segment flag */ #define NSEXRD 0x0080 /* Execute-only (code segment), or * read-only (data segment) */ #define NSRELOC 0x0100 /* Segment has relocations */ #define NSCONFORM 0x0200 /* Conforming segment */ #define NSDPL 0x0C00 /* I/O privilege level (286 DPL bits) */ #define SHIFTDPL 10 /* Left shift count for SEGDPL field */ #define NSDISCARD 0x1000 /* Segment is discardable */ #define NS32BIT 0x2000 /* 32-bit code segment */ #define NSHUGE 0x4000 /* Huge memory segment, length of * segment and minimum allocation * size are in segment sector units */ #define NSPURE NSSHARED /* For compatibility */ #define NSALIGN 9 /* Segment data aligned on 512 byte boundaries */ #define NSLOADED 0x0004 /* ns_sector field contains memory addr */ struct new_segdata /* Segment data */ { union { struct { unsigned short ns_niter; /* number of iterations */ unsigned short ns_nbytes; /* number of bytes */ char ns_iterdata; /* iterated data bytes */ } ns_iter; struct { char ns_data; /* data bytes */ } ns_noniter; } ns_union; }; struct new_rlcinfo /* Relocation info */ { unsigned short nr_nreloc; /* number of relocation items that */ }; /* follow */ struct new_rlc /* Relocation item */ { char nr_stype; /* Source type */ char nr_flags; /* Flag byte */ unsigned short nr_soff; /* Source offset */ union { struct { char nr_segno; /* Target segment number */ char nr_res; /* Reserved */ unsigned short nr_entry; /* Target Entry Table offset */ } nr_intref; /* Internal reference */ struct { unsigned short nr_mod; /* Index into Module Reference Table */ unsigned short nr_proc; /* Procedure ordinal or name offset */ } nr_import; /* Import */ struct { unsigned short nr_ostype; /* OSFIXUP type */ unsigned short nr_osres; /* reserved */ } nr_osfix; /* Operating system fixup */ } nr_union; /* Union */ }; #define NR_STYPE(x) (x).nr_stype #define NR_FLAGS(x) (x).nr_flags #define NR_SOFF(x) (x).nr_soff #define NR_SEGNO(x) (x).nr_union.nr_intref.nr_segno #define NR_RES(x) (x).nr_union.nr_intref.nr_res #define NR_ENTRY(x) (x).nr_union.nr_intref.nr_entry #define NR_MOD(x) (x).nr_union.nr_import.nr_mod #define NR_PROC(x) (x).nr_union.nr_import.nr_proc #define NR_OSTYPE(x) (x).nr_union.nr_osfix.nr_ostype #define NR_OSRES(x) (x).nr_union.nr_osfix.nr_osres /* * Format of NR_STYPE(x): * * xxxxx Unused * sss Source type */ #define NRSTYP 0x0f /* Source type mask */ #define NRSBYT 0x00 /* lo byte */ #define NRSSEG 0x02 /* 16-bit segment */ #define NRSPTR 0x03 /* 32-bit pointer */ #define NRSOFF 0x05 /* 16-bit offset */ #define NRSPTR48 0x0B /* 48-bit pointer */ #define NRSOFF32 0x0D /* 32-bit offset */ /* * Format of NR_FLAGS(x): * * xxxxx Unused * a Additive fixup * rr Reference type */ #define NRADD 0x04 /* Additive fixup */ #define NRRTYP 0x03 /* Reference type mask */ #define NRRINT 0x00 /* Internal reference */ #define NRRORD 0x01 /* Import by ordinal */ #define NRRNAM 0x02 /* Import by name */ #define NRROSF 0x03 /* Operating system fixup */ /* Resource type or name string */ struct rsrc_string { char rs_len; /* number of bytes in string */ char rs_string[ 1 ]; /* text of string */ }; #define RS_LEN( x ) (x).rs_len #define RS_STRING( x ) (x).rs_string /* Resource type information block */ struct rsrc_typeinfo { unsigned short rt_id; unsigned short rt_nres; long rt_proc; }; #define RT_ID( x ) (x).rt_id #define RT_NRES( x ) (x).rt_nres #define RT_PROC( x ) (x).rt_proc /* Resource name information block */ struct rsrc_nameinfo { /* The following two fields must be shifted left by the value of */ /* the rs_align field to compute their actual value. This allows */ /* resources to be larger than 64k, but they do not need to be */ /* aligned on 512 byte boundaries, the way segments are. */ unsigned short rn_offset; /* file offset to resource data */ unsigned short rn_length; /* length of resource data */ unsigned short rn_flags; /* resource flags */ unsigned short rn_id; /* resource name id */ unsigned short rn_handle; /* If loaded, then global handle */ unsigned short rn_usage; /* Initially zero. Number of times */ /* the handle for this resource has */ /* been given out */ }; #define RN_OFFSET( x ) (x).rn_offset #define RN_LENGTH( x ) (x).rn_length #define RN_FLAGS( x ) (x).rn_flags #define RN_ID( x ) (x).rn_id #define RN_HANDLE( x ) (x).rn_handle #define RN_USAGE( x ) (x).rn_usage #define RSORDID 0x8000 /* if high bit of ID set then integer id */ /* otherwise ID is offset of string from the beginning of the resource table */ /* Ideally these are the same as the */ /* corresponding segment flags */ #define RNMOVE 0x0010 /* Moveable resource */ #define RNPURE 0x0020 /* Pure (read-only) resource */ #define RNPRELOAD 0x0040 /* Preloaded resource */ #define RNDISCARD 0xF000 /* Discard priority level for resource */ /* Resource table */ struct new_rsrc { unsigned short rs_align; /* alignment shift count for resources */ struct rsrc_typeinfo rs_typeinfo; }; #define RS_ALIGN( x ) (x).rs_align 컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Figure D-5. The NEWEXE.H C header file, which defines the structure of the tables in OS/2 load modules.