Provide better FQDN support

We strip FQDNs by default because of the inherent problem
of interacting with users, who generally don't like typing
all that extra stuff. However, that creates a problem when
being provided FQDN input during things like nspace registration.

So add an MCA param to control the strip operation instead of
only switching it on/off via info directing during init.
Add logic to the nspace registration process to perform the
strip and add aliases (for the case where the host failed
to provide them).

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit c36cae0)

Pass the uid/gid for client connections

We added the client_connected2 server module upcall so we
could pass information to the host about the connecting client.
User it to pass the uid and gid of the client. Terminate
the connection attempt if the host rejects it.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit 633068a)

Prevent memory overrun in regx calculation

If we do use the native regx component, ensure we don't
overrun the prefix array when assemplix the prefix
on long hostnames

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit 37ff4df)

Pass the client's pid as well

Include the client's pid in the info passed to
the host via client_connected2.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit e0e2974)

Provide more info on connections

When a client connects to the server, pass the proc's
pid plus the real user and group IDs in addition to
the effective ones. When a tool connects, pass those
values plus the pid, cmd line, and PMIx version info.

Add attributes for the real user and group IDs to
distinguish them from the effective values.

Add new info-list APIs for uniquely moving values
onto the list. Provide an "overwrite" flag to indicate
that the current value it to be overwritten by the
new one.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit 3162ba5)

Extend authentication support

Provide the ability to include/exclude connections from
tools whose user IDs are different from that of the server
(i.e., "foreign" tools). Add an attribute to direct that
behavior, default to "exclude". If we allow foreign tools,
then modify the rendezvous file permissions to allow read
by others. Track both the real user/group IDs vs the
effective ones in case someone wants to check both. Pass
more information up to the server client_connected2 and
tool_connection upcalls so the server can make more
informed decisions.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit d577396)

Update listener thread setting of permissions on connection files.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit cc49332)