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.
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.
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: Daniel 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: Daniel P. Berrange <berrange@redhat.com>
Commit 75c1256 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).
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: Gao 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: Gao 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: Daniel 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: Eric 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.
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: Daniel P. Berrange <berrange@redhat.com>
Create parent directroy for hostdev automatically when we
start a lxc domain or attach a hostdev to a lxc domain.
Signed-off-by: Gao 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: Gao 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: Richard Weinberger <richard@nod.at>
libivrt lxc can only set generic weight for container,
This patch allows user to setup per device blkio
weigh for container.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
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: Daniel P. Berrange <berrange@redhat.com>
Since these devices are created for the container.
the owner should be the root user of the container.
Signed-off-by: Gao 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: Gao 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: Gao 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: Gao 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: Gao feng <gaofeng@cn.fujitsu.com>
User namespace will be enabled only when the idmap exist
in configuration.
If you want disable user namespace,just remove these
elements from XML.
If kernel doesn't support user namespace and idmap exist
in configuration file, libvirt lxc will start failed and
return "Kernel doesn't support user namespace" message.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
As a consequence of the cgroup layout changes from commit 'cfed9ad4', the
lxcDomainGetSchedulerParameters[Flags]()' and lxcGetSchedulerType() APIs
failed to return data for a non running domain. This can be seen through
a 'virsh schedinfo <domain>' command which returns:
Scheduler : Unknown
error: Requested operation is not valid: cgroup CPU controller is not mounted
Prior to that change a non running domain would return:
Scheduler : posix
cpu_shares : 0
vcpu_period : 0
vcpu_quota : 0
emulator_period: 0
emulator_quota : 0
This patch will restore the capability to return configuration only data
for a non running domain regardless of whether cgroups are available.
By default files in a FUSE mount can only be accessed by the
user which created them, even if the file permissions would
otherwise allow it. To allow other users to access the FUSE
mount the 'allow_other' mount option must be used. This bug
prevented non-root users in an LXC container from reading
the /proc/meminfo file.
https://bugzilla.redhat.com/show_bug.cgi?id=967977
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Earlier commit f7e8653f dropped support for using LXC with
kernels having single-instance devpts filesystem from the
LXC controller. It forgot to remove the same code from the
LXC container setup.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
