code review 144010043: go.sys/unix: undo CL 119530044's effects in go.sys for BSD

go.sys/unix: undo CL 119530044's effects in go.sys for BSD

That CL worked around a bug present in the
OS X Yosemite Public Beta versions 1 and 2.
Beta 3 (released today) has fixed the bug.

[r, 2014-09-16 17:37:39]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go.sys

[bradfitz, 2014-09-16 17:39:12]

LGTM


On Tue, Sep 16, 2014 at 1:37 PM, <r@golang.org> wrote:

> Reviewers: golang-codereviews,
>
> Message:
> Hello golang-codereviews@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go.sys
>
>
> Description:
> go.sys/unix: undo CL 119530044's effects in go.sys for BSD
>
> That CL worked around a bug present in the
> OS X Yosemite Public Beta versions 1 and 2.
> Beta 3 (released today) has fixed the bug.
>
> Please review this at https://codereview.appspot.com/144010043/
>
> Affected files (+1, -34 lines):
>   M unix/syscall_bsd.go
>
>
> Index: unix/syscall_bsd.go
> ===================================================================
> --- a/unix/syscall_bsd.go
> +++ b/unix/syscall_bsd.go
> @@ -69,40 +69,7 @@
>         // actual system call is getdirentries64, 64 is a good guess.
>         // TODO(rsc): Can we use a single global basep for all calls?
>         var base = (*uintptr)(unsafe.Pointer(new(uint64)))
> -       n, err = Getdirentries(fd, buf, base)
> -
> -       // On OS X 10.10 Yosemite, if you have a directory that can be
> returned
> -       // in a single getdirentries64 call (for example, a directory with
> one file),
> -       // and you read from the directory at EOF twice, you get EOF both
> times:
> -       //      fd = open("dir")
> -       //      getdirentries64(fd) // returns data
> -       //      getdirentries64(fd) // returns 0 (EOF)
> -       //      getdirentries64(fd) // returns 0 (EOF)
> -       //
> -       // But if you remove the file in the middle between the two calls,
> the
> -       // second call returns an error instead.
> -       //      fd = open("dir")
> -       //      getdirentries64(fd) // returns data
> -       //      getdirentries64(fd) // returns 0 (EOF)
> -       //      remove("dir/file")
> -       //      getdirentries64(fd) // returns ENOENT/EINVAL
> -       //
> -       // Whether you get ENOENT or EINVAL depends on exactly what was
> -       // in the directory. It is deterministic, just data-dependent.
> -       //
> -       // This only happens in small directories. A directory containing
> more data
> -       // than fits in a 4k getdirentries64 call will return EOF
> correctly.
> -       // (It's not clear if the criteria is that the directory be split
> across multiple
> -       // getdirentries64 calls or that it be split across multiple file
> system blocks.)
> -       //
> -       // We could change package os to avoid the second read at EOF,
> -       // and maybe we should, but that's a bit involved.
> -       // For now, treat the EINVAL/ENOENT as EOF.
> -       if runtime.GOOS == "darwin" && (err == EINVAL || err == ENOENT) {
> -               err = nil
> -       }
> -
> -       return
> +       return Getdirentries(fd, buf, base)
>  }
>
>  // Wait status is 7 bits at bottom, either 0 (exited),
>
>
> --
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[r, 2014-09-16 17:39:37]

*** Submitted as
https://code.google.com/p/go/source/detail?r=681c8e647b62&repo=sys ***

go.sys/unix: undo CL 119530044's effects in go.sys for BSD

That CL worked around a bug present in the
OS X Yosemite Public Beta versions 1 and 2.
Beta 3 (released today) has fixed the bug.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/144010043