The activeUsbHostdevs item in LXCDriver are lockable, but the lock has
to be called explicitly. Call the virObject(Un)Lock() in order to
achieve mutual exclusion once lxcDriverLock is removed.

The 'driver->caps' pointer can be changed on the fly. Accessing
it currently requires the global driver lock. Isolate this
access in a single helper, so a future patch can relax the
locking constraints.

Annotate the fields in virLXCDriverPtr to indicate the locking
rules for their use.

Currently the virLXCDriverPtr struct contains an wide variety
of data with varying access needs. Move all the static config
data into a dedicated virLXCDriverConfigPtr object. The only
locking requirement is to hold the driver lock, while obtaining
an instance of virLXCDriverConfigPtr. Once a reference is held
on the config object, it can be used completely lockless since
it is immutable.

NB, not all APIs correctly hold the driver lock while getting
a reference to the config object in this patch. This is safe
for now since the config is never updated on the fly. Later
patches will address this fully.

It is not used anywhere, so it makes no sense to have it there.

Merge the virCommandPreserveFD / virCommandTransferFD methods
into a single virCommandPasFD method, and use a new
VIR_COMMAND_PASS_FD_CLOSE_PARENT to indicate their difference
in behaviour
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Wire up the new virDomainCreate{XML}WithFiles methods in the
LXC driver, so that FDs get passed down to the init process.

The lxc_container code needs to do a little dance in order
to renumber the file descriptors it receives into linear
order, starting from STDERR_FILENO + 1.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Commit 75c12564 states that virGetGroupList must not be called
between fork and exec, then commit ee777e99 promptly violated
that for lxc.

Patch originally posted by Eric Blake <eblake@redhat.com>.

Currently, if the primary security driver is 'none', we skip
initializing caps->host.secModels. This means, later, when LXC domain
XML is parsed and <seclabel type='none'/> is found (see
virSecurityLabelDefsParseXML), the model name is not copied to the
seclabel. This leads to subsequent crash in virSecurityManagerGenLabel
where we call STREQ() over the model (note, that we are expecting model
to be !NULL).

The owner of this host devices should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

These host devices are created for container,
the owner should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Otherwise the container will fail to start if we
enable user namespace, since there is no rights to
do mknod in uninit user namespace.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

The owner of this disk device should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

lxc driver will use this function to change the owner
of hot added devices.

Move virLXCControllerChown to lxc_container.c and Rename
it to lxcContainerChown.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

These disk devices are created for container,
the owner should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Since mknod in container is forbidden, we should setup disks
on host side.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

When failing to start a container due to inaccessible root
filesystem path, we did not log any meaningful error. Add a
few debug statements to assist diagnosis
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=964358

POSIX states that multi-threaded apps should not use functions
that are not async-signal-safe between fork and exec, yet we
were using getpwuid_r and initgroups.  Although rare, it is
possible to hit deadlock in the child, when it tries to grab
a mutex that was already held by another thread in the parent.
I actually hit this deadlock when testing multiple domains
being started in parallel with a command hook, with the following
backtrace in the child:

 Thread 1 (Thread 0x7fd56bbf2700 (LWP 3212)):
 #0  __lll_lock_wait ()
     at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:136
 #1  0x00007fd5761e7388 in _L_lock_854 () from /lib64/libpthread.so.0
 #2  0x00007fd5761e7257 in __pthread_mutex_lock (mutex=0x7fd56be00360)
     at pthread_mutex_lock.c:61
 #3  0x00007fd56bbf9fc5 in _nss_files_getpwuid_r (uid=0, result=0x7fd56bbf0c70,
     buffer=0x7fd55c2a65f0 "", buflen=1024, errnop=0x7fd56bbf25b8)
     at nss_files/files-pwd.c:40
 #4  0x00007fd575aeff1d in __getpwuid_r (uid=0, resbuf=0x7fd56bbf0c70,
     buffer=0x7fd55c2a65f0 "", buflen=1024, result=0x7fd56bbf0cb0)
     at ../nss/getXXbyYY_r.c:253
 #5  0x00007fd578aebafc in virSetUIDGID (uid=0, gid=0) at util/virutil.c:1031
 #6  0x00007fd578aebf43 in virSetUIDGIDWithCaps (uid=0, gid=0, capBits=0,
     clearExistingCaps=true) at util/virutil.c:1388
 #7  0x00007fd578a9a20b in virExec (cmd=0x7fd55c231f10) at util/vircommand.c:654
 #8  0x00007fd578a9dfa2 in virCommandRunAsync (cmd=0x7fd55c231f10, pid=0x0)
     at util/vircommand.c:2247
 #9  0x00007fd578a9d74e in virCommandRun (cmd=0x7fd55c231f10, exitstatus=0x0)
     at util/vircommand.c:2100
 #10 0x00007fd56326fde5 in qemuProcessStart (conn=0x7fd53c000df0,
     driver=0x7fd55c0dc4f0, vm=0x7fd54800b100, migrateFrom=0x0, stdin_fd=-1,
     stdin_path=0x0, snapshot=0x0, vmop=VIR_NETDEV_VPORT_PROFILE_OP_CREATE,
     flags=1) at qemu/qemu_process.c:3694
 ...

The solution is to split the work of getpwuid_r/initgroups into the
unsafe portions (getgrouplist, called pre-fork) and safe portions
(setgroups, called post-fork).

* src/util/virutil.h (virSetUIDGID, virSetUIDGIDWithCaps): Adjust
signature.
* src/util/virutil.c (virSetUIDGID): Add parameters.
(virSetUIDGIDWithCaps): Adjust clients.
* src/util/vircommand.c (virExec): Likewise.
* src/util/virfile.c (virFileAccessibleAs, virFileOpenForked)
(virDirCreate): Likewise.
* src/security/security_dac.c (virSecurityDACSetProcessLabel):
Likewise.
* src/lxc/lxc_container.c (lxcContainerSetID): Likewise.
* configure.ac (AC_CHECK_FUNCS_ONCE): Check for setgroups, not
initgroups.
Signed-off-by: NEric Blake <eblake@redhat.com>

Recent changes uncovered a NEGATIVE_RETURNS in the return from sysconf()
when processing a for loop in virtTestCaptureProgramExecChild() in
testutils.c

Code review uncovered 3 other code paths with the same condition that
weren't found by Covirity, so fixed those as well.

these parameters shouldn't be marked as ATTRIBUTE_UNUSED.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Similarly to VIR_STRDUP, we want the OOM error to be reported in
VIR_ALLOC and friends.

Create parent directroy for hostdev automatically when we
start a lxc domain or attach a hostdev to a lxc domain.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

This helper function is used to create parent directory for
the hostdev which will be added to the container. If the
parent directory of this hostdev doesn't exist, the mknod of
the hostdev will fail. eg with /dev/net/tun
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Many applications use /dev/tty to read from stdin.
e.g. zypper on openSUSE.

Let's create this device node to unbreak those applications.
As /dev/tty is a synonym for the current controlling terminal
it cannot harm the host or any other containers.
Signed-off-by: NRichard Weinberger <richard@nod.at>

Ensure that all APIs which list domain objects filter
them against the access control system.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

libivrt lxc can only set generic weight for container,
This patch allows user to setup per device blkio
weigh for container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

We forgot to free the stack when Kernel doesn't
support user namespace.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Add some debug logging of LXC wait/continue messages
and uid/gid map update code.

User namespaces will deny the ability to mount the SELinux
filesystem. This is harmless for libvirt's LXC needs, so the
error can be ignored.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The owner of the /proc/meminfo in container should
be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

These files are created for container,
the owner should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Since these devices are created for the container.
the owner should be the root user of the container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

container will create /dev/pts directory in /dev.
the owner of /dev should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Since these tty devices will be used by container,
the owner of them should be the root user of container.

This patch also adds a new function virLXCControllerChown,
we can use this general function to change the owner of
files.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

user namespace doesn't allow to create devices in
uninit userns. We should create devices on host side.

We first mount tmpfs on dev directroy under state dir
of container. then create devices under this dev dir.

Finally in container, mount the dev directroy created
on host to the /dev/ directroy of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

This patch introduces new helper function
virLXCControllerSetupUserns, in this function,
we set the files uid_map and gid_map of the init
task of container.

lxcContainerSetID is used for creating cred for
tasks running in container. Since after setuid/setgid,
we may be a new user. This patch calls lxcContainerSetUserns
at first to make sure the new created files belong to
right user.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>