hpi::get_host_by_name() / hpi::get_host_by_addr() not defined for Linux/Solaris

[Tom Rodriguez]

I vaguely remember from the early days that the HPI network interface  
was needed because a posix style network API wasn't available on all  
versions of windows, so we had to use winsock directly.  There's also  
some overly complex layering going on where the JVM imports some  
interfaces and then exports back to libjava/libnet through the JVM_  
functions.  We only export the network related JVM_ functions on  
windows since the other platforms use posix directly.  The hpi class  
in hotspot declares all the network functions but only provides  
definitions on windows, presumably because they weren't needed on  
other platforms.  So basically it's a bit of a historical mess.

Additionally the HPI layer has it's own semantics related to  
interruptible I/O which can make it a little challenging to use them  
and also makes it's less than ideal as a bottom level interface inside  
hotspot.  It should be easy to fix the ostream code by providing a  
platform definition of the needed hpi socket functions, either by  
actually calling into the hpi or simply providing platform dependent  
direct calls to the appropriate posix interface.  Even if the HPI goes  
away as an external lib, I suspect at least some of the code will have  
to live in some place we can access it, unless we can stop using  
winsock on windows and use sockets directly.  So basically I think  
using the hpi internally to hotspot for writing socket code would be  
fine until a better strategy comes along.

tom

On Sep 15, 2008, at 8:35 AM, Volker Simonis wrote:

> Hi,
>
> is there a specific reason why some of the hpi-methods declared in
> "src/share/vm/runtime/hpi.hpp" are not defined for Linux/Solaris (e.g.
> hpi::get_host_by_*()).
>
> This leads to ugly code like:
>
> #ifdef _WINDOWS
>    struct hostent* host = hpi::get_host_by_name((char*)ip);
> #else
>    struct hostent* host = gethostbyname(ip);
> #endif
>
> in "src/share/vm/utilities/ostream.cpp".
>
> What's the general advice if one needs to use for example networking
> functions in HotSpot coding. Should the hpi-methods still be used? I
> remember sombody on this list (Keith???) was saying they'll get
> obsolete some day?
>
> Regards,
> Volker