[ On Thursday, July 27, 2000 at 10:50:36 (-0400), Andrew Brown wrote: ]
> Subject: Re: bin/10625: /usr/bin/cmp is unable to compare rather large files
>
> >However I'm not sure the bug is *really* fixed.  Shouldn't the test used
> >to avoid mmap() be to see if the length is bigger than (SIZE_T_MAX / 2)?
> 
> if mmap is so great, wouldn't it make sense to use a moving mmap (ie,
> mmap, scan, munmap, mmap next chunk...) instead of falling back to
> plain old read?

Well, yeah!

> then again...if mmap is so great, why doesn't cat use it?  then cat
> would be just six system calls for each (regular) file.

"If I had a hammer...."  :-)

> >Does mmap() really fail if the file is bigger than the *remaining* size
> >of the process's address space (the manual page makes no obvious claims
> >along these lines)?
> 
> common sense says it should.

There've been some more or less similarly stupid bugs in various mmap()
implementations in the past....

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods@acm.org>      <robohack!woods>
Planix, Inc. <woods@planix.com>; Secrets of the Weird <woods@weird.com>