Hey all,
I'm not very great with the inner workings of GNU or Cygwin libc, so
please bear with me if I make any mistakes or misunderstandings.
I was trying to get GNU coreutils to work on Cygwin. Maybe this seems
weird to you guys, because Cygwin has coreutils, but there are a few
reasons:
- Cygwin didn't have md5sum, GNU coreutils did (and I need md5sum)
- It should work, and "Because I Can" is always a valid reason in UNIX world
- I'm trying to bootstrap Debian on Cygwin, and coreutils from Debian is
my first try; getting coreutils from Cygwin may be done later.
However, I noticed there are some very weird bugs happening. See for
example, this bug in cat (don't look at the title of the page, I blamed
bash first)
http://paster.dazjorz.com/?p=3845
A friend of mine and me have been trying to figure out what causes this.
First, we tested if it wasn't a bug in open() + fork(). This seemed not
to be the case. So we started looking further, and we're down to GNU
`cat` calling freopen(). This is not POSIX-compliant and can cause
problems like this.
`cat` and other coreutils tools only call freopen() if O_BINARY is
defined on this platform. It's defined on Cygwin, because Cygwin makes a
difference between O_TEXT and O_BINARY.
1. Why does Cygwin distinguish between O_TEXT and O_BINARY? Shouldn't
this difference be removed from the Linux API side of Cygwin?
2. I don't know why coreutils is calling freopen() at all. Should I
patch it out completely, or add something like an #ifndef __CYGWIN__
around the pieces of code in question?
I'm hesitant to patch coreutils, so I'm asking for your opinion first.
Thanks for any replies,
Sjors
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