dtrace discuss - Dec 2009 - find sockaddr by file descriptor number

It''s trivial to find file path by file descriptor: fds[fd].fi_pathname.
Is there a place where I can get socket address in case fd corresponds to a
socket?
I''d like to intercept read/write syscalls and print file names or
socket addresses for each read/write.

Thanks!
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On Mon, Dec 28, 2009 at 09:31:06AM -0800, Alexey Vladykin wrote:
> Is there a place where I can get socket address in case fd corresponds to a
> socket?  I''d like to intercept read/write syscalls and print file
names or
> socket addresses for each read/write.
Problem with sockets is read & write aren''t the only syscalls that
let you
send data.  There''s also the send*() and recv*() families of calls.  In
the
case of {send,recv}{msg,to,from}(), that sockaddr can change (imagine a DNS
server, e.g.).

Your best bet might have been the IP provider, but then you don''t get
UNIX
sockets or the generalized file-descriptor intercepts you seem to want.

Dan

Once I deal with read/write, it should be easy to handle send*/recv* too.

I didn''t get your argument that sockaddr can change. Once connection is
established, the remote address can''t change. It is IP address, so DNS
is not involved. One exception is sendto() with a socket in connection-less
mode, when it''s possible to specify destination address for each
message. But it''s not a huge problem.

OpenSolaris sources
(http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/stand/lib/sock/socket.c)
define
struct inetboot_socket sockets[MAXSOCKET] = { 0 };
which contains all the addresses I need. Is it possible to access this array
from DTrace?
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