Description

This devhlp is used to read from a file opened with DevHlp_OpenFile, in contrast to a normal read, a start position can be specified.

Calling convention

• ES:DI = point to a SYIReadFileAt structure
• DL = 082h

Returns

• CY=0, AX = 0: read okay
• CY=1, AX = ERROR_BAD_LENGTH: packet is invalid
• CY=1, AX = <>0: other filesystem related errors

Data structures

; assembler structure

SYIReadFile	struc
length		dw	12	; length of structure (must be 12)
buffer		dd	?	; 16:16 address of a read buffer
size		dd	?	; number of bytes to read
startpos	dd	?	; starting position of read relative to
				; start of file
SYIReadFile	ends

Restrictions

Valid at INIT time only. Although the size argument of the data structure implies, I’d recommend to better not read more than 32K at a time. Note that the buffer itself is segmented, so DMA overrun and other effects might apply, depending on the quality of the miniIFS in use.

Bugs

IMHO, the length of structure should be 14, not 12.

Description

This is the kernel support for the security enabling services.

Calling convention

Subfunction: DHSEC_SETIMPORT
This function will load the ISS Security Event Service Routine Table into the kernel. Each service routine will be called upon a certain API event, such as opening a file, or starting a program. There are also service routines to capture each DOS API routine (if you are interested in this, and you are considered trustworthy by me, i.e. well-known in the OS/2 hacker’s scene, I can give you code for these rather tricky routines – collectors and gatherers stay off!).

• EAX = 073ae3627h special function key
• ECX = FLAT (linear) address of table to be submitted
• DL = 044h

Subfunction: DHSEC_GETEXPORT
This function will return the table of security helper functions for file access. These helpers provide low level access to any file in the system which is not controlled by security services (unlike the normal DOS API).

• EAX = 048a78df8h special function key
• ECX = FLAT (linear) address of a buffer to receive the 40 byte table
• DL = 044h

Subfunction: DHSEC_GETINFO
Internally used function, information withheld intentionally.

Subfunction: DHSEC_AUDITHOOK
Internally used function, information withheld intentionally.

Subfunction: DHSEC_TRUSTEDPATHNOTIFY
Internally used function, information withheld intentionally.

Subfunction: DHSEC_IMPORT_PDF
Special purpose function for an IBM product, information withheld intentionally.

Subfunction: DHSEC_IMPORT_AV
Special purpose function for an IBM product, information withheld intentionally.

Returns

• CY=0, AX = 0, okay
• CY=1, AX = APIRET error code

Data structures

It is beyond the scope of this text to explain all details of SES. Consult the Red Book SG2446-68, also available via DevCon. IBM has decided, as of SG2446-68, appendix A, not to publish the SES KPI. You can ask, according to the Red Book for this documentation at:

IBM Manager of OS/2 Security
Mail Stop 9171
11400 Burnet Rd.
Austin, Texas 78758
(is this address still valid?)

Restrictions

Valid at any time.

Description

This devhlp allows to open a file for read access in the Init routine of a BASEDEV.

Calling convention

ES:DI = point to a SYIOpenFile structure

• DL = 07fh

Returns

• CY=0, AX = 0: okay, structure pointed to by ES:DI is modified
• CY=1, AX = ERROR_BAD_LENGTH: packet is invalid
• CY=1, AX = <>0: other filesystem related errors

Data structures

; assembler structure
SYIOpenFile struc
length		dw	8	; length of structure, must contain value 8
name		dd	?	; 16:16 ASCIZ pathname
fsize		dd	?	; returned: size of file
SYIOpenFile	ends

Restrictions

Valid at INIT time only. This routine is not handle based, so it is only possible to have only one file at a time open. This routine uses the corresponding function of the miniFSD, not normal file I/O, thus access is restricted. At this phase of boot, drive letters do not yet exist, and IFSs/DMDs might not yet have been initialized, so you can only open files on the boot drive. Depending on the type of IPL (e.g. loading from a network file system), other restrictions might apply.

Bugs

The returned file size is unreliable, the value returned is always

Republished without permission from Holger Veit’s long gone webpages – MKG

Description

This devhlp closes a file opened by DevHlp_OpenFile.

Calling convention

• ES:DI = point to a SYICloseFile structure
• DL = 080h

Returns

• CY=0, AX = 0, okay
• CY=1, AX = APIRET error code

Data structures

; assembler structure
SYICloseFile	struc
length		dw	2	; length of structure (must be 2)
SYICloseFile	ends

Restrictions

Valid at INIT time only. See also restrictions of DevHlp_OpenFile

Description

This is a special entry into DosKillProcess, which is more rigid in killing processes: the killed process won’t be able to execute its kill signal handler, thus open files might not be closed properly. A process currently operating in ring 0 will terminate as soon as it returns to ring 3 (this means, a process blocked in the kernel, e.g. on a pending I/O, can still not be killed). This devhlp corresponds to the SESKillProcess API.
Calling convention

• BX = Pid of process to kill, 0 = current process
• DL = 07dh

Returns

• CY=0, AX = 0, okay
• CY=1, AX = APIRET error code

Data structures

None.

Restrictions

Valid at TASK time only.