abap program for Customized, dynamic login screen

REPORT ZTSTPOOL.
************************************************************************
* Customized dynamic login screen for 3.1 and 4.0 systems
* (SAPMSST can not be edited any more)
* To make it work:
* - Create a 83X11 subscreen area TESTSCR on the bottom of SAPMSYST/0020
* - In the flow logic at the end of the PBA insert:
* CALL SUBSCREEN TESTSCR INCLUDING 'ZTSTPOOL' '0010'.
* - Create the subscreen type screen 0010 with module pool ZTSTPOOL
* - Create the output type fields line1 ... line9 for 0010/ZTSTPOOL
* - Call DISPLAY_DATA from the PBO of 0010/ZTSTPOOL
* - Create a UNIX file with the system description, important messages
* on a shared directory like /usr/sap/trans with the following format:
* Z|SID|Description
* M|SID|System message line1
* M|SID|System message line2
************************************************************************
*
* Data for the communication between the screen and the modules
DATA: MESSAGE(20), LINE1(81), LINE2(81), LINE3(81), LINE4(81),
LINE5(81), LINE6(81), LINE7(81), LINE8(81), LINE9(81).
* The PBO of the subscreen
MODULE DISPLAY_DATA OUTPUT.
* Local data
DATA: L(200), A1(81), A2(81), A3(81).
DATA: DESRCIPTION(6) VALUE 'Z| |',
SYSTEM_MESSAGE(6) VALUE 'M| |'.
DATA: BEGIN OF A.
INCLUDE STRUCTURE RFCSI.
DATA: END OF A.
DATA: BEGIN OF LINE_TBL OCCURS 100.
INCLUDE STRUCTURE SPFLIST.
DATA: END OF LINE_TBL.
*
* Only for testing: run it only for a specific terminal
* CALL FUNCTION 'RFC_SYSTEM_INFO' DESTINATION 'SAPGUI'
* IMPORTING RFCSI_EXPORT = A.
* IF A CS 'RCHEN'.
* End of Only for testing
*
* Create the SID specific search patterns
DESRCIPTION+2(3) = SY-SYSID.
SYSTEM_MESSAGE+2(3) = SY-SYSID.
* Trick to avoid OPEN DATASET (no user->no authorization->open fails)
CALL FUNCTION 'RZL_READ_FILE_LOCAL'
EXPORTING
DIRECTORY = '/usr/sap/trans'
NAME = 'system_descriptions'
TABLES
LINE_TBL = LINE_TBL
EXCEPTIONS
NOT_FOUND = 1.
* If the file is missing: do not display anything
IF SY-SUBRC = 1.
EXIT.
ENDIF.
* Get the system description and important messages from the file
LOOP AT LINE_TBL.
L = LINE_TBL-LINE.
IF L CS DESRCIPTION.
SPLIT L AT '|' INTO A1 A2 A3.
LINE1 = A3.
ENDIF.
IF L CS SYSTEM_MESSAGE.
SPLIT L AT '|' INTO A1 A2 A3.
IF LINE3 IS INITIAL.
LINE3+6 = A3.
ELSE.
IF LINE4 IS INITIAL.
LINE4+6 = A3.
ELSE.
IF LINE5 IS INITIAL.
LINE5+6 = A3.
ELSE.
LINE6+6 = A3.
ENDIF.
ENDIF.
ENDIF.
ENDIF.
* Some hardcoded information added here
LINE8 = 'For more information visit:'.
LINE9 = 'http://company_web_server/basis_support.htm'.
ENDLOOP.
* ENDIF. "Only for testing
ENDMODULE.