The Lightsabre Project
======================
Part 002 - Getting Started
With the COBOL compiler and assembler verified as working, things were
looking pretty rosy in the lightsabre garden. Real life intervened
last weekend unfortunately, so I was limited to reading the sockets
API documentation until I could get a decent amount of keyboard time
in.
I got chance to spend a few hours on coding today, thanks to some time
off after working the weekend. And I'm happy to announce I've actually
made some progress - my gopher client now speaks TCP/IP! (cue wild
cheers and applause)
Here's a screenshot of things as they stand:
********************************* TOP OF DATA **********************************
gopher for mvs
initializing sockets api
getting foreign host IP
hostname-value gopher.floodgap.com
hostname-length 0019
hostaddr-value 18206629
getting socket
connecting to remote server...
closing socket
terminating sockets api
done!
******************************** BOTTOM OF DATA ********************************
---
OK, the UI could do with a bit of polish, but I'm fairly happy that
things are heading in the right direction. My JCL to compile and run
the code needed an addition to allow the linker to pull in the sockets
library:
//LEEGCLG JOB ,'LEE',CLASS=A,MSGCLASS=H,MSGLEVEL=(1,1)
//STEP1 EXEC PROC=IGYWCLG,PARM.COBOL='XREF,FLAG(I,E)'
//COBOL.SYSIN DD DSN=LEE.GOPHER.COBOL(GOPHER),DISP=SHR
//COBOL.SYSOUT DD SYSOUT=*
//LKED.SYSLIB DD DSNAME=&LIBPRFX..SCEELKED,DISP=SHR
// DD DSN=TCPIP.SEZATCP(EZACICAL),DISP=SHR
(you can see the TCPIP bit at the bottom)
but other than that, things are more-or-less working as described in
the documentation.
The more eagle-eyed or zealous sundogs among you will have immediately
leapt on one particular item in the client output:
hostname-value gopher.floodgap.com
Let me explain. It seems that the TCP/IP stack I'm using (IBM
Communications Server) is... well... it's 'heirloom' shall we say? The
software dates to around the mid-to-late 90s.
The sockets library (EZASOKET) provides a 'gethostbyname' function[1]
like pretty much any IP stack since Methuselah was a lad. However, for
reasons best known to the designers, instead of using (what the docs
admit is 'the standard') a 255-character field for the host name
you're querying, it uses a 24-character field[2]. Twenty-four. The
native C call naturally lets you provide a character pointer for this,
but whoever did the CALL (ie. non-C) interface work was clearly of the
'640K is enough for anyone' school.
So, querying the host I wanted to use - 'republic.circumlunar.space'
is a non-starter (agonizingly 2 characters over my buffer limit).
This being the case, I've got two choices:
1. Write my own COBOL-callable 'gethostbyname' routine in C, and link
to that.
2. Ignore it for the time being.
Guess which one I'm going with?
[1]
https://www.ibm.com/support/libraryserver/BOOKS/F1AF2030/3.1.9.13?SHELF=F1A0BK0A&DT=20000531171939
[2]
https://www.ibm.com/support/libraryserver/BOOKS/F1AF2030/3.4.7.8?SHELF=F1A0BK0A&DT=20000531171939
