On Tue, Dec 11, 2018 at 03:08:38PM -0700, Todd C. Miller wrote: > On Tue, 11 Dec 2018 20:35:05 +0100, Sebastien Marie wrote: > > > According to stdio.h, 6 = __SNBF | __SRD, so "unbuffered" and "OK to read". > > > > the feof() call returns false, the python code interpretes it as an error. > > > > When looking at fread(3) code in libc, I found that we doesn't set > > __SEOF when the FILE is unbuffered. > > Yes, that is a bug. The code should probably be calling __srefill(), > though we'd need to set _bf._base and _bf._size appropriately so > it doesn't use _nbuf. Some care is required... > > - todd
It seems it is the rediscover of a previously signaled bug by zhuk@ . see https://marc.info/?l=openbsd-tech&m=152554758706248&w=2 I found it after setting up a patch, and it is mostly the same than the proposed one by zhuk@, so I take his diff (exactly, only the chunk that correct the bug. his diff also corrects something else, but I prefer to take care to only one thing a time). The approch is to directly set __SEOF or __SERR. It is more simple than trying to reuse __srefill(). Index: stdio/fread.c =================================================================== RCS file: /cvs/src/lib/libc/stdio/fread.c,v retrieving revision 1.15 diff -u -p -r1.15 fread.c --- stdio/fread.c 21 Sep 2016 04:38:56 -0000 1.15 +++ stdio/fread.c 12 Dec 2018 07:52:02 -0000 @@ -79,6 +79,10 @@ fread(void *buf, size_t size, size_t cou p += r; resid -= r; } + if (r == 0) + fp->_flags |= __SEOF; + else if (r < 0) + fp->_flags |= __SERR; FUNLOCKFILE(fp); return ((total - resid) / size); } I tested it with mercurial, and it corrects the problem. Thanks. -- Sebastien Marie
