[Linux-cluster] Multicast for GFS?

Lazar Obradovic laza at yu.net
Mon Aug 9 13:10:30 UTC 2004


On Mon, 2004-08-09 at 13:32, Lazar Obradovic wrote:
> since it contains my mcast addr instead of real host addr. I'm debugging
> it now to see where the error happens... 

... and the reason why i had trouble is: 
debugging code revealed that he structure propperly contains node's
unicast address along with a hostname *before* bhe struct is inited by
gethostbyname2() call.

After that, both bhe and he point to new structure, which holds hostent
struct for mcast address... That's why bind() failed, so I had to use
IPADDR_ANY... 

If we all look at manual page for gethostbyname(3), we can see that this
behaviour is not strange, as noted in "NOTES": 

The functions gethostbyname() and gethostbyaddr() may return pointers to
static data, which may be overwritten by later calls. Copying the struct
hostent does not suffice, since it contains pointers - a deep copy is
required.

I'll correct this later and send a patch :) 

-- 
Lazar Obradovic, System Engineer
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