[PATCH] SOCK_CLOEXEC for opening sockets

[Chris Hegarty]

Andrew,

I filed the following issue to track this:
   https://bugs.openjdk.java.net/browse/JDK-8207335

Once you produce an updated patch, I can review and
sponsor this for you.

-Chris.

On 12/07/18 08:21, Andrew Luo wrote:
> Thanks, I can refactor it.  I’m not as familiar with the OpenJDK 
> architecture – should I just duplicate the function into libnio or is 
> there some common utility library that I should move it into?  Also, let 
> me know what in net_util_* needs cleanup.  The other instances of 
> socket/socketpair in Mac/AIX/Solaris I’m willing to handle as well.
> 
> Files are mostly already handled: 
> https://bugs.openjdk.java.net/browse/JDK-8043780 (in a similar way – 
> O_CLOEXEC on systems that support it and fcntl on other POSIX systems).  
> One other resource you mentioned is epolls.  Perhaps there’s also other 
> file descriptors that are being used elsewhere, but I think it will take 
> me longer time to figure out.  I’m willing to work on that as well if we 
> all think it’s a good idea.
> 
> Anyways, while I agree that it would be ideal to address those other 
> file descriptors as well, is it ok to address those in a separate 
> changeset, or do you think that this changeset doesn’t really provide 
> value unless we make this change everywhere?  Sockets are somewhat more 
> problematic than other types of file descriptors (in my opinion) as if 
> you use it to listen on a port and then fork child processes (from 
> native code) then restart the parent process, it won’t be able to listen 
> to the same port until all of the children processes (of the previous 
> process) exit/close the fd.  Other file descriptors, unless you open in 
> exclusive mode, won’t have the same problem (although the behavior is 
> undesirable).
> 
> Thanks,
> 
> -Andrew
> 
> *From:*Alan Bateman <Alan.Bateman at oracle.com>
> *Sent:* Wednesday, July 11, 2018 11:59 PM
> *To:* Andrew Luo <andrewluotechnologies at outlook.com>
> *Cc:* Martin Buchholz <martinrb at google.com>; net-dev at openjdk.java.net
> *Subject:* Re: [PATCH] SOCK_CLOEXEC for opening sockets
> 
> On 12/07/2018 05:55, Andrew Luo wrote:
> 
>     Ok, fixed a few more places (and a bug where fcntl was being run on
>     a -1 fd).  Patch is below, let me know if there’s any other
>     suggestions/etc.
> 
> The file system code should not be calling into NET_* functions.  The 
> changes to net_util_* will also need cleanup. Otherwise I think you've 
> got all the places in the networking / NIO APIs, at least on Linux. 
> There are others on macOS, Solaris, ... of course.
> 
> That said,  I assume we have many more places in the JDK that have file 
> descriptors to open files and other resources. If we really want to 
> support the case of someone calling fork/exec from JNI code then it will 
> likely need work in several other areas.
> 
> -Alan
>