Give default value of O_NOFOLLOW if it is not defined

[Alan Bateman]

On 29/12/2011 03:27, Charles Lee wrote:
>
> Hi Alan,
>
> I have the same concern. So I did a grep on "LinkOption" and found 
> that the Usage of O_NOFOLLOW fell into two categories:
> 1. used to make a value to a boolean: flags.followLinks,  
> Util.followLinks. In this situation give O_NOFOLLOW to 0 will do no harm.
> 2. pass a part of flags to the native directly: open and openat in the 
> UnixChannelFactory, UnixPath and UnixSecureDirectoryStream. In this 
> situation, maybe we should throw UnsupportedOperationException?
>
> What do you think if I use 0 as a flag to O_NOFOLLOW is not supported?
>
I'll send mail when I get back next week but off-hand:

1. SecureDirectoryStream can't be supported on platforms that don't have 
O_NOFOLLOW so it means that UnixFileSystemProvider.newDirectoryStream 
will require to check this before deciding the type of DirectoryStream 
to return.

2. UnixChannelFactory (which is used by 
UnixFileSystemProvider.newFileChannel and newAsynchronousFileChannel) 
will need to fail with UOE if NOFOLLOW_LINKS is specified as an option 
when opening a file. It's not one of the standard opens and so it's 
required to be supported, it just happens that all the platforms we 
currently

3. Where a FileAttributeView is created that doesn't follow sym links 
then it's highly platform specific if it can be used to update the 
attributes of the sym link. This is where 
UnixPath.openForAttributeAccess is used. I need to double check the 
javadoc to see how this is specified as I can't recall off-hand if this 
is treated as an UOE or an IOException (I think the latter).

-Alan.