This patch is somewhat more specialized than the tracepoint stuff, but 
may be of wider interest, so we offer it for your consideration.  It 
adds a login capability to the remote protocol; the user sets a username 
and password in GDB, then upon connection to a target that requires 
them, GDB supplies the two.  It is completely up to the target what do 
with them, for instance it could simply close the connection in response 
to a bad login.

The design is simple, and not especially secure, as the password is sent 
in the clear - it's mostly appropriate for direct connections or secured 
intranets.  We don't do anything to conceal the password from the 
console, but one could add a non-echoing reader, and write a password 
show that kept it concealed.

The patch below is actually somewhat out of date, but it should be 
sufficient for discussion, and I'll update it into a real patch if the 
consensus is in favor of including this capability in GDB.

Stan

2009-02-04  Stan Shebs  <stan@codesourcery.com>

    Remote login support.
    gdb/
    * remote.c (remote_username, remote_password): New globals.
    (struct remote_state): New field must_auth.
    (PACKET_qAuth): New enum.
    (remote_start_remote): Send qAuth if required.
    (remote_query_auth): New.
    (remote_must_auth_feature): New.
    (remote_protocol_features): Add MustAuth.
    (_initialize_remote): Add qAuth packet, set commands.

    gdb/doc/
    * gdb.texinfo (Remote Configuration): Document set remote username
    and password.
    (General Query Packets): Document qAuth packet and MustAuth feature.