a bug in u386mon & what is sys3b(2) ???????

[James Howard]

In article <1990Jul16.231429.1592 at scuzzy.uucp>, src at scuzzy.uucp (Heiko
Blume) writes:

[ u386mon bug description deleted ]

 > now for the weird part. i grep'ed around and found <sys/swap.h> which says:
 > 
 > 
 > /*	The following struct is used by the sys3b system call.
 >                                             ^^^^^^^^^^^^^^^^^
 >  *	If the first argument to the sys3b system call is 3,
 >  *	then the call pertains to the swap file.  In this case,
 >  *	the second argument is a pointer to a structure of the
 >  *	following format which contains the parameters for the
 >  *	operation to be performed.
 >  */
 > [........]
 > 
 > huh?! what system call ? of course that call isn't in any manuals i have
 > and, needless to say, of course i wrote a little program saying
 > sys3b(3,&swapinfo), which gave me 'unresolved external' on linking.
 > it's also isn't in any library. well, i could lseek in the kernel
 > to find the table where the info for all the swap files is
(swaptab[MSFILES])
 > but i'd prefer a clean way of course. also i can't image /etc/swap to munge
 > around in the kernel to add swap space (it's much too fast for that,
and that
 > would be *dirty* as it could be).

Well it looks like ISC forgot to edit the machine specific stuff in 
<sys/swap.h>.  The sys3b(2) call is for AT&T 3B series computers.  It is 
a machine specific call, there is an analogous sysi86(2) call under ISC.  
Look up the sysi86 call instead, and you will see how the structure 
declaration immediately following the text quoted above correlates with 
the man page information.  The parameters are slightly different, but ISC 
has a way to get to the swap areas also.  Look in the header <sys/sysi86.h>
for more info.



James Howard        Dell Computer Corp.        !'s:uunet!dell!mustang!jrh
(512) 343-3480      9505 Arboretum Blvd        @'s:jrh at mustang.dell.com
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