Bug 21948

Summary: RLIM_INFINITY definition is apparently wrong
Product: Base System Reporter: jau
Component: kernAssignee: freebsd-bugs (Nobody) <bugs>
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Unspecified   
Hardware: Any   
OS: Any   

Description jau 2000-10-13 07:30:00 UTC 
RLIM_INFINITY is currently defined as follows...

#define RLIM_INFINITY   ((rlim_t)(((u_quad_t)1 << 63) - 1))

This is apparently wrong, because using an unsigned quad length
integer to represent the value hints that the intended bit pattern
to represent infinity is all 64 bits one, 0xFFFFFFFFFFFFFFFF.
The current definition makes the pattern anyhow 0x3FFFFFFFFFFFFFFF,
which does not require an unsigned type at all.

Fix: 

Either 
#define RLIM_INFINITY   ((rlim_t)((u_quad_t) ~0ULL))
or
#define RLIM_INFINITY   ((rlim_t)(~ (u_quad_t) 0))
Comment 1 Bruce Evans 2000-10-13 11:33:30 UTC 
On Thu, 12 Oct 2000 jau@iki.fi wrote:

> >Description:
> RLIM_INFINITY is currently defined as follows...
> 
> #define RLIM_INFINITY   ((rlim_t)(((u_quad_t)1 << 63) - 1))
> 
> This is apparently wrong, because using an unsigned quad length
> integer to represent the value hints that the intended bit pattern
> to represent infinity is all 64 bits one, 0xFFFFFFFFFFFFFFFF.
> The current definition makes the pattern anyhow 0x3FFFFFFFFFFFFFFF,
> which does not require an unsigned type at all.

Actually, the current definition makes the bit pattern 0x7FFFFFFFFFFFFFFF.
This doesn't require an unsigned type, but one more than it does (on most
machines), since subtracting one from the value with bit pattern
0x8000000000000000 would overflow on most machines.

Bruce
Comment 2 iedowse freebsd_committer freebsd_triage 2001-11-17 19:45:52 UTC 
State Changed
From-To: open->feedback


What was the conclusion here? Is this a bug or not?
Comment 3 iedowse freebsd_committer freebsd_triage 2001-11-21 18:20:05 UTC 
State Changed
From-To: feedback->closed


The submitter agrees that due to the current type of rlim_t (quad_t), 
the present value of RLIM_INFINITY is reasonable (it is defined as 
0x7fffffffffffffff, the largest value representable by the type).