Use the newly introduced close callback helpers to make the code look just a
bit cleaner and more importantly, to fix the following memleak regarding a
dangling virAdmConnect object reference caused by assigning NULL to the close
callback data once the catch-disconnect routine used the callback followed
by a comparison of NULL to the originally defined close callback (which at that
moment had already been NULL'd by remoteAdminClientCloseFunc) in
virAdmConnectCloseCallbackUnregister.

717 (88 direct, 629 indirect) bytes in 1 blocks are definitely lost record
 110 of 141
    at 0x4C2A988: calloc (vg_replace_malloc.c:711)
    by 0x530696F: virAllocVar (viralloc.c:560)
    by 0x53689E6: virObjectNew (virobject.c:193)
    by 0x5368B5E: virObjectLockableNew (virobject.c:219)
    by 0x4E3E7EE: virAdmConnectNew (datatypes.c:900)
    by 0x4E398BB: virAdmConnectOpen (libvirt-admin.c:220)
    by 0x10D3E3: vshAdmConnect (virt-admin.c:161)
    by 0x10D624: vshAdmReconnect (virt-admin.c:215)
    by 0x10DB0A: cmdConnect (virt-admin.c:353)
    by 0x11288F: vshCommandRun (vsh.c:1313)
    by 0x10FDB6: main (virt-admin.c:1439)

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1357358Signed-off-by: NErik Skultety <eskultet@redhat.com>

Opposite operation to virAdmServerGetClientLimits. Understandably though,
setting values for current number of clients connected or still waiting
for authentication does not make sense, since changes to these values are event
dependent, i.e. a client connects - counter is increased. Thus only the limits
to maximum clients connected and waiting for authentication can be set. Should
a request for other controls to be set arrive (provided such a setting will
be first introduced to the config), the set of configuration controls can be
later expanded (thanks to typed params). This patch also introduces a
constraint that the maximum number of clients waiting for authentication has to
be less than the overall maximum number of clients connected and any attempt to
violate this constraint will be denied.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Enable retrieval of the number of maximum clients connected to all sockets
combined, as well as the number of maximum clients waiting for authentication,
in order to be successfully connected. These are the attributes configurable
through libvirtd.conf, however, it could be handy to not only know values for
these limits, but also the values for the current number of clients
connected and number of clients currently waiting for authentication which are
changing dynamically. This API does both, retrieves the limits as well as the
current dynamic values.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Unlike the previous commit, we do actually support one client-side only flag
VIR_CONNECT_NO_ALIASES, so besides removing the check for flags this flag
has to be masked out before sending a message to the daemon, otherwise it
would trigger an error when checking flags on the daemon side.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Expose a public API to retrieve some identity and connection information about
a client connected to the specified server on daemon. The identity info
retrieved is mostly connection transport dependent, i.e. there won't be any
socket address returned for a local (UNIX socket) connection, while on the
other hand, when connected through TLS or unencrypted TCP, obviously no UNIX
process identification will be present in the returned data. All supported
values that can be returned in typed params are exposed and documented in
include/libvirt/libvirt-admin.h
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Finally add public method to retrieve the list of currently connected clients
to a given server.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Since threadpool increments the current number of threads according to current
load, i.e. how many jobs are waiting in the queue. The count however, is
constrained by max and min limits of workers. The logic of this new API works
like this:
    1) setting the minimum
        a) When the limit is increased, depending on the current number of
           threads, new threads are possibly spawned if the current number of
           threads is less than the new minimum limit
        b) Decreasing the minimum limit has no possible effect on the current
           number of threads
    2) setting the maximum
        a) Icreasing the maximum limit has no immediate effect on the current
           number of threads, it only allows the threadpool to spawn more
           threads when new jobs, that would otherwise end up queued, arrive.
        b) Decreasing the maximum limit may affect the current number of
           threads, if the current number of threads is less than the new
           maximum limit. Since there may be some ongoing time-consuming jobs
           that would effectively block this API from killing any threads.
           Therefore, this API is asynchronous with best-effort execution,
           i.e. the necessary number of workers will be terminated once they
           finish their previous job, unless other workers had already
           terminated, decreasing the limit to the requested value.
    3) setting priority workers
        - both increase and decrease in count of these workers have an
          immediate impact on the current number of workers, new ones will be
          spawned or some of them get terminated respectively.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

New API to retrieve current server workerpool specs. Since it uses typed
parameters, more specs to retrieve can be further included in the pool of
supported ones.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

Since we have the opportunity now, let's save some precious code lines.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

When virt-admin is run with valgrind, this kind of output can be obtained:

HEAP SUMMARY:
  in use at exit: 134,589 bytes in 1,031 blocks
  total heap usage: 2,667 allocs, 1,636 frees, 496,755 bytes allocated

88 bytes in 1 blocks are definitely lost in loss record 82 of 128
 at 0x4C2A9C7: calloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
 by 0x52F6D1F: virAllocVar (viralloc.c:560)
 by 0x5350268: virObjectNew (virobject.c:193)
 by 0x53503E0: virObjectLockableNew (virobject.c:219)
 by 0x4E3BBCB: virAdmConnectNew (datatypes.c:832)
 by 0x4E38495: virAdmConnectOpen (libvirt-admin.c:209)
 by 0x10C541: vshAdmConnect (virt-admin.c:107)
 by 0x10C7B2: vshAdmReconnect (virt-admin.c:163)
 by 0x10CC7C: cmdConnect (virt-admin.c:298)
 by 0x110838: vshCommandRun (vsh.c:1224)
 by 0x10DFD8: main (virt-admin.c:862)

 LEAK SUMMARY:
    definitely lost: 88 bytes in 1 blocks
    indirectly lost: 0 bytes in 0 blocks
    possibly lost: 0 bytes in 0 blocks
    still reachable: 134,501 bytes in 1,030 blocks
    suppressed: 0 bytes in 0 blocks

This is because virNetClientSetCloseCallback was being reinitialized
incorrectly. By resetting the callbacks in a proper way, the leak is fixed.

This API is merely a convenience API, i.e. when managing clients connected to
daemon's servers, we should know (convenience) which server the specific client
is connected to. This implies a client-side representation of a server along
with a basic API to let the administrating client know what servers are actually
available on the daemon.
Signed-off-by: NErik Skultety <eskultet@redhat.com>
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

Commmit df8192aa introduced admin related rename and some minor
(caused by automated approach, aka sed) and some more severe isues along with
it. First reason to revert is the inconsistency with libvirt library.
Although we deal with the daemon directly rather than with a specific
hypervisor, we still do have a connection. That being said, contributors might
get under the impression that AdmDaemonNew would spawn/start a new daemon
(since it's admin API, why not...), or AdmDaemonClose would do the exact
opposite or they might expect DaemonIsAlive report overall status of the daemon
which definitely isn't the case.
The second reason to revert this patch is renaming virt-admin client. The
client tool does not necessarily have to reflect the names of the API's it's
using in his internals. An example would be 's/vshAdmConnect/vshAdmDaemon'
where noone can be certain of what the latter function really does. The former
is quite expressive about some connection magic it performs, but the latter does
not say anything, especially when vshAdmReconnect and vshAdmDisconnect were
left untouched.

virAdmConnect was named after virConnect, but after some discussions,
most of the APIs called will be working with remote daemon and starting
them virAdmDaemon will make more sense.  Only possibly controversal name
is CloseCallback (de)registration, and connecting to the daemon (which
will still be Open/Close), but even this makes sense if one thinks about
the daemon being opened and closed, e.g. as file, etc.

This way all the APIs working with the daemon will start with
virAdmDaemon prefix, they will accept virAdmDaemonPtr as first parameter
and that will better suit with other namings as well (virDomain*,
virAdmServer*, etc.).

Because in virt-admin, the connection name does not refer to a struct
that would have a connect in its name, also adjust 'connname' in
clients.  And because it is not used anywhere in the vsh code, move it
from there into each client.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

As we need a client disconnect handler, we also need a mechanism to register
such handlers for a client. This patch introduced both the close callbacks and
also the client vshAdmCatchDisconnect handler to be registered with it. By
registering the handler we still need to make sure the client can react to
daemon's events like disconnect or keepalive, so asynchronous I/O event polling
is necessary to be enabled too.

As we plan to add more and more logic to remote connecting methods,
these cannot be generated from admin_protocol.x anymore. Instead,
this patch implements these to methods explicitly.

By moving the remote version into a separate module, we gain a slightly
better maintainability in the long run than just by leaving it in one
place with the existing libvirt-admin library which can start getting
pretty messy later on.