Prevent an endless loop while executing lxc-attach in the background:

The kernel might fire SIGTTOU while an ioctl() in tcsetattr()
is executed. When the ioctl() is resumed and retries,
the signal handler interrupts it again.

We can't configure the TTY to stop sending
the signals in the first place since that
is a modification/write to the TTY already.

Still we clear the TOSTOP flag to prevent further signals.

Command to reproduce the hang:
----------------------------
cat > lxc_hang.sh << EOF
/usr/bin/timeout 5s /usr/bin/lxc-attach -n SOMECONTAINER -- /bin/true
EOF
sh lxc_hang.sh    # hangs
----------------------------
Signed-off-by: Thomas Jarosch <thomas.jarosch@intra2net.com>

confile: clear lxc.network.<n>.ipv{4,6} when empty

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

conf/ile: make sure buffer is large enough

util: update setproctitle comments

Add LXC template script of Sabayon OS

conf.c: In function 'lxc_assign_network':
conf.c:3096:25: error: '%lu' directive output may be truncated writing between 1 and 20 bytes into a region of size 19 [-Werror=format-truncation=]
   snprintf(pidstr, 19, "%lu", (unsigned long) pid);
                         ^~~
conf.c:3096:24: note: using the range [1, 18446744073709551615] for directive argument
   snprintf(pidstr, 19, "%lu", (unsigned long) pid);
                        ^~~~~
In file included from /usr/include/stdio.h:938:0,
                 from conf.c:35:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:64:10: note: format output between 2 and 21 bytes into a destination of size 19
   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        __bos (__s), __fmt, __va_arg_pack ());
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
confile.c: In function 'network_new_hwaddrs':
confile.c:2889:38: error: '%02x' directive output may be truncated writing between 2 and 8 bytes into a region of size 6 [-Werror=format-truncation=]
  snprintf(hwaddr, 18, "00:16:3e:%02x:%02x:%02x",
                                      ^~~~
confile.c:2889:23: note: using the range [0, 4294967295] for directive argument
  snprintf(hwaddr, 18, "00:16:3e:%02x:%02x:%02x",
                       ^~~~~~~~~~~~~~~~~~~~~~~~~
confile.c:2889:23: note: using the range [0, 4294967295] for directive argument
In file included from /usr/include/stdio.h:938:0,
                 from confile.c:24:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:64:10: note: format output between 18 and 36 bytes into a destination of size 18
   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        __bos (__s), __fmt, __va_arg_pack ());
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Not sure whether the latter is really a problem. We might need an additional
fix later on.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

util: always malloc for setproctitle

Closes #1407
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

lxc-opensuse: fix default value for release code

Signed-off-by: Maxime Besson <maxime.besson@smile.fr>

Signed-off-by: Geaaru <geaaru@gmail.com>

Allow build without sys/capability.h

There is no guard clause around a reference to CAP_EFFECTIVE and
CAP_SETGID, causing compilation to fail if sys/capability.h is not
available.
Signed-off-by: Brett Neumeier <brett@neumeier.us>

Signed-off-by: Geaaru <geaaru@gmail.com>

Fix typo

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

Make lxc-start-ephemeral Python 3.2-compatible

On Ubuntu 12.04 LTS with Python 3.2, `lxc-start-ephemeral` breaks as
follows:

    Traceback (most recent call last):
      File "/usr/bin/lxc-start-ephemeral", line 371, in attach_as_user
      File "/usr/lib/python3.2/subprocess.py", line 515, in check_output
      File "/usr/lib/python3.2/subprocess.py", line 732, in __init__
    LookupError: unknown encoding: ANSI_X3.4-1968

This is because `universal_newlines=True` causes `subprocess` to use
`io.TextIOWrapper`, and in versions of Python earlier than 3.3 that
fetched the preferred encoding using `locale.getpreferredencoding()`
rather than `locale.getpreferredencoding(False)`, thereby changing the
locale and causing codecs to be reloaded.  However, `attach_as_user`
runs inside the container and thus can't rely on having access to the
same Python standard library on disk.

The workaround is to decode by hand instead, avoiding the temporary
change of locale.
Signed-off-by: Colin Watson <cjwatson@ubuntu.com>

Use AC_HEADER_MAJOR to detect major()/minor()/makedev()

Before the change build failed on Gentoo as:

  bdev/lxclvm.c: In function 'lvm_detect':
  bdev/lxclvm.c:140:4: error: implicit declaration of function 'major' [-Werror=implicit-function-declaration]
    major(statbuf.st_rdev), minor(statbuf.st_rdev));
    ^~~~~
  bdev/lxclvm.c:140:28: error: implicit declaration of function 'minor' [-Werror=implicit-function-declaration]
    major(statbuf.st_rdev), minor(statbuf.st_rdev));
                            ^~~~~

glibc plans to remove <sys/sysmacros.h> from glibc's <sys/types.h>:
    https://sourceware.org/ml/libc-alpha/2015-11/msg00253.html

Gentoo already applied glibc patch to experimental glibc-2.24
to start preparingfor the change.

Autoconf has AC_HEADER_MAJOR to find out which header defines
reqiured macros:
    https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Particular-Headers.html

This change should also increase portability across other libcs.

Bug: https://bugs.gentoo.org/604360Signed-off-by: Sergei Trofimovich <siarheit@google.com>

add cgroupfs-mount to Should-Start/Stop sysvinit LSB headers

otherwise init might try to start the containers before cgroupfs was
mounted.

Debian-Bug: https://bugs.debian.org/850212Signed-off-by: Evgeni Golov <evgeni@debian.org>

tools/lxc-start: remove c->is_defined(c) check

We do not check here whether the container is defined, because we support
volatile containers. Which means the container does not need to be created for
it to be started. You can just pass a configuration file as argument and start
the container right away.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

start: fix execute and improve setgroups() calls

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

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

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>

tools: only check for O_RDONLY

tree-wide: Sic semper assertis!

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>

python3-lxc: fix api_test.py on s390x

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>

conf: fix suggest_default_idmap()

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>

tests: skip unpriv tests on broken overlay module