This is the ring-3 32-bit linear address space's code segment, and it is
hardcoded on OS/2. Generally it isn't explicitly referenced, but things
like CSet/2 would generate thunks that hardcode jmps to it when returning
to 32-bit mode, so you have to patch those out (Linux also hardcodes a
code segment number, but doesn't promise the value won't change, and indeed,
it's different between x86, x86-64, and x86-on-x86-64 apps).
- Let allocateSelector() specify number of pages to allocate.
- Let findSelector() specify if this is a code or data segment.
- Let findSelector() choose if this is a code or data segment
if the caller doesn't know (DosFlatToSel(), etc).
Now we save off the stack pointer and immediately jmp back to 32-bit. This is
slightly easier to debug (gdb doesn't get confused by addresses, registers or
disassembly), and puts all the 32-bit registers in a 32-bit code segment, to
keep things sane.
Also: doesn't write duplicate instructions to update %ds and %es if they are
the same values in Linux land.
Finger (etc) also rely on MPTN\DLL\tnls32.dll, which I pulled out a copy of
OS/2 Warp 4.52, which loads and limps along enough to not be a problem.
Reimplementing that library is going to be a pain, so that's a job for another
day. Inexplicably, tnls32 references pmgpi.dll's GpiQueryTextBox(), so I put a
stub for that in, too, but we're nowhere near really implementing GPI yet.
This is enough to run "finger.exe icculus@icculus.org" and see my .plan file,
which I consider a victory. A few more TCP/IP command line tools aren't far
behind.
This gets us everything we need (I hope!) to support 16-bit code in LX
binaries and call into 16-bit OS/2 APIs. This is just enough to call
into VioGetMode() (which isn't otherwise implemented yet) as an example.
If this is ever used Winelib-style to provide an OS/2 API to native Linux
binaries, the 16-bit system APIs are 32-bit clean and C callable, as one
might expect them to be. All the tapdancing is to support existing LX
binaries in the loader and bridge between the 32-bit clean APIs and
existing 16-bit code that expects to call 16-bit APIs.
This was a staggering amount of effort, but yay!
Other fixes and improvements probably leaked into this commit, as a
lot of code got touched and a lot of research and debugging took place.
Otherwise, it won't be available to DLL init code when run before the
main executable starts.
Fixes Watcom C's wlink.exe crashing because it gets a NULL command line.
I must have been reading docs for device drivers, or something...?
Now it returns the top word of the linear pointer, in hopes that this will
just get mushed back together later, knock on wood.
Ryan C. Gordon