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Re: proposal: module 'accept4'
From: |
Eric Blake |
Subject: |
Re: proposal: module 'accept4' |
Date: |
Sat, 22 Aug 2009 20:49:12 -0600 |
User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.23) Gecko/20090812 Thunderbird/2.0.0.23 Mnenhy/0.7.6.666 |
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According to Bruno Haible on 8/22/2009 3:39 PM:
> Hi,
>
> Here's the proposed module for function 'accept4'.
>
> It does not define the macro SOCK_CLOEXEC. I think this macro should be
> replaced by a separate module, that would then also influence socket(),
> socketpair() - and what about connect()?
socket and socketpair both (need to) honor SOCK_CLOEXEC; but connect does
not create a new fd (it just modifies an existing one) so it doesn't need
any change.
> nfd = _open_osfhandle ((long) new_handle,
> O_NOINHERIT | (flags & (O_TEXT | O_BINARY)));
> if (nfd < 0)
> {
> int saved_errno = errno;
> close (fd);
> errno = saved_errno;
> return -1;
> }
>
> close (fd);
> return nfd;
This means that nfd > fd, so there is a gap in the fd sequence which is
unexpected per POSIX rules. Is it worth the hassle of using
dup2(nfd,fd),close(fd) instead of close(fd)?
> if (flags & SOCK_CLOEXEC)
> {
> int fcntl_flags;
>
> if ((fcntl_flags = fcntl (fd, F_GETFD, 0)) < 0
> || fcntl (fd, F_SETFD, fcntl_flags | FD_CLOEXEC) < 0)
Success for F_SETFD is like F_SETFL - you must compare against explicit -1.
Otherwise, looks sane to me. Do you have a test case in mind?
- --
Don't work too hard, make some time for fun as well!
Eric Blake address@hidden
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