- Use $XDG_RUNTIME_DIR for re-exec state file when running unprivileged.

- argv[0] may not contain a full path to the binary, however it should
  contain something that can be looked up in the PATH. Use execvp() to
  do path lookup on re-exec.

- As per list discussion [1], ignore --daemon on re-exec.

[1] https://www.redhat.com/archives/libvir-list/2013-December/msg00514.htmlSigned-off-by: NMichael Chapman <mike@very.puzzling.org>

Some of our operation denied messages are outright stupid; for
example, if virIdentitySetAttr fails:

error: operation Identity attribute is already set forbidden for read only access

This patch fixes things to a saner:

error: operation forbidden: Identity attribute is already set

It also consolidates the most common usage pattern for operation
denied errors: read-only connections preventing a public API.  In
this case, 'virsh -r -c test:///default destroy test' changes from:

error: operation virDomainDestroy forbidden for read only access

to:

error: operation forbidden: read only access prevents virDomainDestroy

Note that we were previously inconsistent on which APIs used
VIR_FROM_DOM (such as virDomainDestroy) vs. VIR_FROM_NONE (such as
virDomainPMSuspendForDuration).  After this patch, all uses
consistently use VIR_FROM_NONE, on the grounds that it is unlikely
that a caller learning that a call is denied can do anything in
particular with extra knowledge which error domain the call belongs
to (similar to what we did in commit baa72449).

* src/util/virerror.c (virErrorMsg): Rework OPERATION_DENIED error
message.
* src/internal.h (virCheckReadOnlyGoto): New macro.
* src/util/virerror.h (virReportRestrictedError): New macro.
* src/libvirt-lxc.c: Use new macros.
* src/libvirt-qemu.c: Likewise.
* src/libvirt.c: Likewise.
* src/locking/lock_daemon.c (virLockDaemonClientNew): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

This reverts commit 8355d42d.

After some discussion upstream [1] this patch turns out to be spurious.
It better gets reverted prior to a release.

1: https://www.redhat.com/archives/libvir-list/2013-December/msg00563.htmlSigned-off-by: NMichal Privoznik <mprivozn@redhat.com>

Also use a distinct, valid exit status for daemon re-execution failure.
Signed-off-by: NMichael Chapman <mike@very.puzzling.org>

SIGHUP is commonly used to instruct a daemon to reload its config. For
now we should handle it in virtlockd just like SIGUSR1, rather than
having it kill the process.
Signed-off-by: NMichael Chapman <mike@very.puzzling.org>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Most of the usage of getuid()/getgid() is in cases where we are
considering what privileges we have. As such the code should be
using the effective IDs, not real IDs.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Unconditional use of getenv is not secure in setuid env.
While not all libvirt code runs in a setuid env (since
much of it only exists inside libvirtd) this is not always
clear to developers. So make all the code paranoid, even
if it only ever runs inside libvirtd.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Each new VM requires a new connection from libvirtd to virtlockd.
The default max clients limit in virtlockd of 20 is thus woefully
insufficient. virtlockd sockets are only accessible to matching
users, so there is no security need for such a tight limit. Make
it configurable and default to 1024.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The virtlockd/libvirtd daemons had listed '?' as the short option
for --help. getopt_long uses '?' for any unknown option. We want
to be able to distinguish unknown options (which use EXIT_FAILURE)
from correct usage of help (which should use EXIT_SUCCESS). Thus
we should use 'h' as a short option for --help. Also add this to
the man page docs

The virtlockd/libvirtd daemons did not list any short option
for the --version arg. Add -V as a valid short option, since
-v is already used for --verbose.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

This configuration knob lets user to set the length of queue of
connection requests waiting to be accept()-ed by the daemon. IOW, it
just controls the @backlog passed to listen:

  int listen(int sockfd, int backlog);

Since PIDs can be reused, polkit prefers to be given
a (PID,start time) pair. If given a PID on its own,
it will attempt to lookup the start time in /proc/pid/stat,
though this is subject to races.

It is safer if the client app resolves the PID start
time itself, because as long as the app has the client
socket open, the client PID won't be reused.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.

No need to check the run_dir variable twice for NULL.

Add checks for existence of GNUTLS and automatically disable
it if not found.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The virtlockd daemon maintains file locks on behalf of libvirtd
and any VMs it is running. These file locks must be held for as
long as any VM is running. If virtlockd itself ever quits, then
it is expected that a node would be fenced/rebooted. Thus to
allow for software upgrads on live systemd, virtlockd needs the
ability to re-exec() itself.

Upon receipt of SIGUSR1, virtlockd will save its current live
state out to a file /var/run/virtlockd-restart-exec.json
It then re-exec()'s itself with exactly the same argv as it
originally had, and loads the state file, reconstructing any
objects as appropriate.

The state file contains information about all locks held and
all network services and clients currently active. An example
state document is

 {
    "server": {
        "min_workers": 1,
        "max_workers": 20,
        "priority_workers": 0,
        "max_clients": 20,
        "keepaliveInterval": 4294967295,
        "keepaliveCount": 0,
        "keepaliveRequired": false,
        "services": [
            {
                "auth": 0,
                "readonly": false,
                "nrequests_client_max": 1,
                "socks": [
                    {
                        "fd": 6,
                        "errfd": -1,
                        "pid": 0,
                        "isClient": false
                    }
                ]
            }
        ],
        "clients": [
            {
                "auth": 0,
                "readonly": false,
                "nrequests_max": 1,
                "sock": {
                    "fd": 9,
                    "errfd": -1,
                    "pid": 0,
                    "isClient": true
                },
                "privateData": {
                    "restricted": true,
                    "ownerPid": 1722,
                    "ownerId": 6,
                    "ownerName": "f18x86_64",
                    "ownerUUID": "97586ba9-df27-9459-c806-f016c8bbd224"
                }
            },
            {
                "auth": 0,
                "readonly": false,
                "nrequests_max": 1,
                "sock": {
                    "fd": 10,
                    "errfd": -1,
                    "pid": 0,
                    "isClient": true
                },
                "privateData": {
                    "restricted": true,
                    "ownerPid": 1784,
                    "ownerId": 7,
                    "ownerName": "f16x86_64",
                    "ownerUUID": "7b8e5e42-b875-61e9-b981-91ad8fa46979"
                }
            }
        ]
    },
    "defaultLockspace": {
        "resources": [
            {
                "name": "/var/lib/libvirt/images/f16x86_64.raw",
                "path": "/var/lib/libvirt/images/f16x86_64.raw",
                "fd": 14,
                "lockHeld": true,
                "flags": 0,
                "owners": [
                    1784
                ]
            },
            {
                "name": "/var/lib/libvirt/images/shared.img",
                "path": "/var/lib/libvirt/images/shared.img",
                "fd": 12,
                "lockHeld": true,
                "flags": 1,
                "owners": [
                    1722,
                    1784
                ]
            },
            {
                "name": "/var/lib/libvirt/images/f18x86_64.img",
                "path": "/var/lib/libvirt/images/f18x86_64.img",
                "fd": 11,
                "lockHeld": true,
                "flags": 0,
                "owners": [
                    1722
                ]
            }
        ]
    },
    "lockspaces": [

    ],
    "magic": "30199"
 }
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

This enhancement virtlockd so that it can receive a pre-opened
UNIX domain socket from systemd at launch time, and adds the
systemd service/socket unit files

* daemon/libvirtd.service.in: Require virtlockd to be running
* libvirt.spec.in: Add virtlockd systemd files
* src/Makefile.am: Install systemd files
* src/locking/lock_daemon.c: Support socket activation
* src/locking/virtlockd.service.in, src/locking/virtlockd.socket.in:
  systemd unit files
* src/rpc/virnetserverservice.c, src/rpc/virnetserverservice.h:
  Add virNetServerServiceNewFD() method
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Add virNetSocketNewListenFD
  method
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Introduce a lock_daemon_dispatch.c file which implements the
server side dispatcher the RPC APIs previously defined in the
lock protocol.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The virtlockd daemon will maintain locks on behalf of libvirtd.
There are two reasons for it to be separate

 - Avoid risk of other libvirtd threads accidentally
   releasing fcntl() locks by opening + closing a file
   that is locked
 - Ensure locks can be preserved across libvirtd restarts.
   virtlockd will need to be able to re-exec itself while
   maintaining locks. This is simpler to achieve if its
   sole job is maintaining locks
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>