lxc_execute() and lxc-execute where broken when a user tried to switch to a
non-root uid/gid. This prevented necessary setup operations like mounting the
rootfs which require root in the user namespace. This commit separates
switching to root in the user namespace from switching to the requested uid/gid
by lxc_execute().
This should be safe: Once we switched to root in the user namespace via
setuid() and then switch to a non-root uid/gid in the user namespace for
lxc_execute() via setuid() we cannot regain root privileges again. So we can
only make us safer (Unless I forget about some very intricate user namespace
nonsense; which is not as unlikely as I try to make it sound.).
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

This commit adds lxc_switch_uid_gid() which allows to switch the uid and gid of
a process via setuid() and setgid() and lxc_setgroups() which allows to set
groups via setgroups(). The main advantage is that they nicely log the switches
they perform.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

On some Android systems the lxc folders where containers are stored might be
read-only and so checking for O_RDWR, will effectively make the tools useless
on these systems, so let's dumb the check down to O_RDONLY.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

The api_test.py script uses Trusty release by default, which does not
have s390x image. Switch to Xenial to solve this.
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>

We need to remove the newline otherwise lxc_safe_uint() will fail as it detects
an invalid (non-numeric) char in the string.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

This mainly affects Trusty. The 3.13 kernel has a broken overlay module which
does not handle symlinks correctly. This is a problem for containers that use
an overlay based rootfs since safe_mount() uses /proc/<pid>/fd/<fd-number> in
its calls to mount().
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Previously HAVE_LIBGNUTLS was never set in config.h even if gnutls was
detected as AC_CHECK_LIB default action-if-found was overriden by
enable_gnutls=yes
This patch adds an --enable-gnutls option and will call AC_CHECK_LIB
with the default action to write HAVE_LIBGNUTLS in config.h
Signed-off-by: Fabrice Fontaine <fabrice.fontaine@orange.com>

Given commit 330ae3d3:

    lxccontainer: detect if we should send SIGRTMIN+3

    This is required by systemd to cleanly shutdown. Other init systems should not
    have SIGRTMIN+3 in the blocked signals set.

we should stop poking around with sigpwr.target for systemd.
Signed-off-by: Evgeni Golov <evgeni@debian.org>

it might not even be there…
Signed-off-by: Evgeni Golov <evgeni@debian.org>

Removed libgcc_s1 because it breaks container building for openSUSE.

Related: openSUSE/obs-build#188
Signed-off-by: Terzeus S. Dominguez <tsdmgz@gmail.com>

Signed-off-by: Santiago Ruano Rincón <santiago@debian.org>
Signed-off-by: Evgeni Golov <evgeni@debian.org>

Signed-off-by: Santiago Ruano Rincón <santiago@debian.org>
Signed-off-by: Evgeni Golov <evgeni@debian.org>

Uncommented lxc.aa_profile = unconfined. Otherwise, container fails to
start up.
Signed-off-by: Terzeus S. Dominguez <tsdmgz@gmail.com>

Signed-off-by: Terzeus S. Dominguez <tsdmgz@gmail.com>

Aside from adding a 42.2 option, $DISTRO comparisons for Leap have been
changed [ exp ] => [[ exp ]] to accomodate pattern matching for future
releases.
Signed-off-by: Terzeus S. Dominguez <tsdmgz@gmail.com>

Save errno across some calls to close() since it can be
interrupted.
Signed-off-by: Wolfgang Bumiller <wry.git@bumiller.com>

Commit bf39edb3 broke the handling of the getty service file with an '@' character in filename. So the startup condition was not fixed.

Because the parameter was quoted with the causal commit, the escaping has to be removed.

Signed-off-by: Andreas Eberlein foodeas@aeberlein.de

attach: close lsm label file descriptor

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Same change as in 6118210e which was missing in lxc-start
and back then is_defined() wasn't being called.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

- improve logging
- simplify functions
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

gettimeofday() is not async signal safe. So let's switch to clock_gettime() to
be on the safe side.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

- single digit months, days, hours, minutes, and seconds should always be
  preceded by a 0.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

This allows us to generate nice timestamps in a thread-safe manner without
relying on locale touching functions from any libc.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Converts a unix time Epoch given by a struct timespec to a UTC string useable
in our logging functions. Maybe expanded to allow for more generic formatting.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Our log functions need to make extra sure that they are thread-safe. We had
some problems with that before. This especially involves time-conversion
functions. I don't want to find any localtime() or gmtime() functions or
relatives in here. Not even localtime_r() or gmtime_r() or relatives. They all
fiddle with global variables and locking in various libcs. They cause deadlocks
when liblxc is used multi-threaded and no matter how smart you think you are,
you __will__ cause trouble using them.
(As a short example how this can cause trouble: LXD uses forkstart to fork off
a new process that runs the container. At the same time the go runtime LXD
relies on does its own multi-threading thing which we can't control. The
fork()ing + threading then seems to mess with the locking states in these time
functions causing deadlocks.)
The current solution is to be good old unix people and use the Epoch as our
reference point and simply use the seconds and nanoseconds that have past since
then. This relies on clock_gettime() which is explicitly marked MT-Safe with no
restrictions! This way, anyone who is really strongly invested in getting the
actual time the log entry was created, can just convert it for themselves. Our
logging is mostly done for debugging purposes so don't try to make it pretty.
Pretty might cost you thread-safety.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

This macro can be used to set or allocate a string buffer that can hold any
64bit representable number.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

The thread-unsafe functions strsignal() is called in run_buffer() which in turn
is called in run_buffer_argv() which is responsible for running __all__ lxc
hooks. This is pretty dangerous for multi-threaded users like LXD.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Before lxc_monitord called lxc_monitord_cleanup() from a signal handler.  This
function calls a bunch of async signal unsafe functions and basically begs for
deadlocks. This commit switches lxc-monitord to using sigsetjmp() and
siglongjmp() in the signal handler to jump to a cleanup label that call
lxc_monitord_cleanup(). In this way, we avoid using async signal unsafe
functions.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Setting loglevel to DEBUG will allow us to retrieve more useful information in
case something goes wrong. The total size of the log will not increase
significantly.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Execing lxc-monitord is quite a crucial step so let's be very obsessive about
logging possible errors to guide us in debugging.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>