DOS ain't dead - How to compile this program for DOS?

rosegondon

C:\DOS,
18.09.2021, 02:50

How to compile this program for DOS? (Developers)

Hello,

Regarding https://www.fourmilab.ch/onetime/otp-1.2.2.tar.gz

Using DJGPP under Windows I was able to compile it for Win32 target without any problems.

Using equivalent DOS DJGPP build on the same source code all I produced was a long screen of compiler rants about various errors, some with suggestions of fixes based on various "-W" directives, but they were not helpful, because program does not compile, even if some of the errors vanished.

So how to compile this code for DOS (32 bit) target? Please note I am not fluent in C.

---
echo g=ffff:0|debug>nul

sezeroz

18.09.2021, 14:47

@ rosegondon

How to compile this program for DOS?

Post reply

If you patch it like the following, it does compile.
(Not run-tested at all, though.)

--- otp.c~ +++ otp.c @@ -55,8 +55,12 @@ #ifdef WIN32 #include <windows.h> #endif - -#ifdef unix +#ifdef __DJGPP +#define __far +#define _intdos intdos +#define _REGS REGS +#endif +#if defined(unix) && !defined(__DJGPP) #include <sys/time.h> extern int getpid(), getppid(), gethostid(); #endif @@ -189,7 +193,7 @@ #ifdef MSDOS union _REGS ri, ro; #endif -#ifdef unix +#if defined(unix) && !defined(__DJGPP) struct timeval tv; #endif @@ -340,7 +344,7 @@ #define OS_KNOWN 1 #endif -#ifdef unix +#if defined(unix) && !defined(__DJGPP) FILE *rf; size_t ct;

rosegondon

C:\DOS,
18.09.2021, 18:37

@ sezeroz

How to compile this program for DOS?

Post reply

patch.exe from UnxUtils failed, same for patch.exe from Perl for Windows.

Error message:

patching file otp.c Hunk #2 FAILED at 193. patch unexpectedly ends in middle of line Hunk #3 succeeded at 344 with fuzz 2. 1 out of 3 hunks FAILED -- saving rejects to file otp.c.rej

otp.c.rej contents:

*************** *** 189,195 **** #ifdef MSDOS union _REGS ri, ro; #endif - #ifdef unix struct timeval tv; #endif --- 193,199 ---- #ifdef MSDOS union _REGS ri, ro; #endif + #if defined(unix) && !defined(__DJGPP) struct timeval tv; #endif

> If you patch it like the following, it does compile.
> (Not run-tested at all, though.)
>
> > --- otp.c~ > +++ otp.c > @@ -55,8 +55,12 @@ > #ifdef WIN32 > #include <windows.h> > #endif > - > -#ifdef unix > +#ifdef __DJGPP > +#define __far > +#define _intdos intdos > +#define _REGS REGS > +#endif > +#if defined(unix) && !defined(__DJGPP) > #include <sys/time.h> > extern int getpid(), getppid(), gethostid(); > #endif > @@ -189,7 +193,7 @@ > #ifdef MSDOS > union _REGS ri, ro; > #endif > -#ifdef unix > +#if defined(unix) && !defined(__DJGPP) > struct timeval tv; > #endif > > @@ -340,7 +344,7 @@ > #define OS_KNOWN 1 > #endif > > -#ifdef unix > +#if defined(unix) && !defined(__DJGPP) > FILE *rf; > size_t ct; >

---
echo g=ffff:0|debug>nul

tkchia

18.09.2021, 21:16

@ rosegondon

How to compile this program for DOS?

Post reply

Hello rosegondon, hello sezeros,

> patching file otp.c> Hunk #2 FAILED at 193. > patch unexpectedly ends in middle of line > Hunk #3 succeeded at 344 with fuzz 2. > 1 out of 3 hunks FAILED -- saving rejects to file otp.c.rej >

Whitespace issue (argh!). There is a tab character after the first #endif in the rejected patch portion --- you will need to edit the patch to add it in (or maybe change spaces into tabs).

Actually I think sezeros's patch throws away a bit too much code. The Unix-specific code (#ifdef unix ... #endif) tries to gather some bits of randomness by calling gettimeofday(...):

#ifdef unix FILE *rf; size_t ct; gettimeofday(&tv, (struct timezone *) NULL); trash[1] = tv.tv_sec; trash[2] = tv.tv_usec; ... #define OS_KNOWN 1 #endif

... and DJGPP does support gettimeofday(...). Unfortunately, the patch will disable the code, which will reduce the amount of randomness the program can use. There is probably a better way...

Thank you!

---
https://gitlab.com/tkchia · https://codeberg.org/tkchia · 😴 "MOV AX,0D500H+CMOS_REG_D+NMI"

tkchia

18.09.2021, 21:31

@ rosegondon

How to compile this program for DOS?

Post reply

Hello rosegondon,

My proposed modified patch (for now) is as follows:

--- otp.c.orig 2021-09-18 18:49:22.723186562 +0000 +++ otp.c 2021-09-18 19:27:31.893487497 +0000 @@ -57,4 +57,10 @@ #endif +#ifdef __DJGPP +#define __far +#define _intdos intdos +#define _REGS REGS +#endif + #ifdef unix #include <sys/time.h> @@ -311,8 +317,8 @@ ri.h.dl = 0; /* Default drive */ if (_intdos(&ri, &ro) != 0xFFFF) { - trash[1] = (((int32_t) ro.x.ax) << 16) | ro.x.bx; - trash[2] = (((int32_t) ro.x.cx) << 16) | ro.x.dx; + trash[5] = (((int32_t) ro.x.ax) << 16) | ro.x.bx; + trash[6] = (((int32_t) ro.x.cx) << 16) | ro.x.dx; } - trash[4] = (int32_t) (char __far *) trash; + trash[7] = (int32_t) (char __far *) trash; #define OS_KNOWN 1 #endif @@ -353,5 +359,7 @@ trash[4] = getpid(); trash[11] = getppid(); +#ifndef __DJGPP trash[38] = gethostid(); +#endif /* If the system implements /dev/random, obtain 16 bytes of entropy thence. */

Further improvements are probably possible.

Thank you!

---
https://gitlab.com/tkchia · https://codeberg.org/tkchia · 😴 "MOV AX,0D500H+CMOS_REG_D+NMI"

rosegondon

C:\DOS,
19.09.2021, 01:28

@ tkchia

How to compile this program for DOS?

Post reply

Hi sezeroz & tkchia,

@sezeroz, thank you for your patch, after I applied it, program compiled regardless of patching errors.

@tkchia, your patch triggers whitespace errors too, I will try to
manually apply your modifications in source code. Probably something happens with text when copying&pasting from this forum to patch file.

Thank you for you help, now I will make code changes and tests on my DOS machine and I hope to come back with results soon.

> Hello rosegondon,
>
> My proposed modified patch (for now) is as follows:
>
> --- otp.c.orig 2021-09-18 18:49:22.723186562 +0000> +++ otp.c 2021-09-18 19:27:31.893487497 +0000 > @@ -57,4 +57,10 @@ > #endif > > +#ifdef __DJGPP > +#define __far > +#define _intdos intdos > +#define _REGS REGS > +#endif > + > #ifdef unix > #include <sys/time.h> > @@ -311,8 +317,8 @@ > ri.h.dl = 0; /* Default drive */ > if (_intdos(&ri, &ro) != 0xFFFF) { > - trash[1] = (((int32_t) ro.x.ax) << 16) | ro.x.bx; > - trash[2] = (((int32_t) ro.x.cx) << 16) | ro.x.dx; > + trash[5] = (((int32_t) ro.x.ax) << 16) | ro.x.bx; > + trash[6] = (((int32_t) ro.x.cx) << 16) | ro.x.dx; > } > - trash[4] = (int32_t) (char __far *) trash; > + trash[7] = (int32_t) (char __far *) trash; > #define OS_KNOWN 1 > #endif > @@ -353,5 +359,7 @@ > trash[4] = getpid(); > trash[11] = getppid(); > +#ifndef __DJGPP > trash[38] = gethostid(); > +#endif > /* If the system implements /dev/random, obtain 16 bytes > of entropy thence. */
>
> Further improvements are probably possible.
>
> Thank you!

---
echo g=ffff:0|debug>nul

Rugxulo

Usono,
19.09.2021, 06:20

@ rosegondon

How to compile this program for DOS? (patch)

Post reply

> @tkchia, your patch triggers whitespace errors too, I will try to
> manually apply your modifications in source code. Probably something
> happens with text when copying&pasting from this forum to patch file.

The Linux manual for patch says this (which was what I faintly remembered):

> -l or --ignore-whitespace
> Match patterns loosely, in case tabs or spaces have been
> munged in your files. Any sequence of one or more blanks in
> the patch file matches any sequence in the original file, and
> sequences of blanks at the ends of lines are ignored. Normal
> characters must still match exactly. Each line of the context
> must still match a line in the original file.

rosegondon

C:\DOS,
19.09.2021, 09:40

@ Rugxulo

How to compile this program for DOS? (patch)

Post reply

@Rugxulo, thank you! After using this directive patches were applied without errors.

> > @tkchia, your patch triggers whitespace errors too

> > -l or --ignore-whitespace
> > Match patterns loosely, in case tabs or spaces have been
> > munged in your files.

---
echo g=ffff:0|debug>nul