read(2) and thus bsdiff is limited to 2^31 bytes

[Matthew Macy]

 ---- On Sun, 22 May 2016 15:54:14 -0700 Joerg Sonnenberger <joerg at bec.de> wrote ---- 
 > On Sun, May 22, 2016 at 10:54:30PM +0200, Dirk Engling wrote: 
 > > When trying to bsdiff two DVD images, I noticed it failing due to 
 > > read(2) returning EINVAL to the tool. man 2 read says, this would only 
 > > happen for a negative value for fildes, which clearly was not true. 
 >  
 > I would classify that as implementation bug. It seems perfectly sensible 
 > to turn overly large requests into a short read/write, even for blocking 
 > files. But erroring out seems to be quite wrong to me. 
 >  

read(2) takes a size_t so this is clearly an internal bug where it's an int and treating it as a negative value.

-M