consolidate missing C library functions into utils.h

This fixes the build of lxccontainer.c on systems that have __NR_setns
but not HAVE_SETNS.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
fix memory leaks in cgroup functions

There were several memory leaks in the cgroup functions, notably in the
success cases.

The cgpath test program was refactored and additional tests added to it.
It was used in various modes under valgrind to test that the leaks were
fixed.

Simplify lxc_cgroup_path_get() and cgroup_path_get by having them return a
char * instead of an int and an output char * argument. The only return
values ever used were -1 and 0, which are now handled with NULL and non-NULL
returns respectively.

Use consistent variable names of cgabspath when refering to an absolute path
to a cgroup subsystem or file, and cgrelpath when refering to a container
"group/name" within the cgroup heirarchy.

Remove unused subsystem argument to lxc_cmd_get_cgroup_path().

Remove unused #define MAXPRIOLEN

Make template arg to lxcapi_create() const

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxclock: Replace named sempahore with flock

The problem: if a task is killed while holding a posix semaphore,
there appears to be no way to have the semaphore be reliably
autmoatically released.  The only trick which seemed promising
is to store the pid of the lock holder in some file and have
later lock seekers check whether that task has died.

Instead of going down that route, this patch switches from a
named posix semaphore to flock.  The advantage is that when
the task is killed, its fds are closed and locks are automatically
released.

The disadvantage of flock is that we can't rely on it to exclude
threads.  Therefore c->slock must now always be wrapped inside
c->privlock.

This patch survived basic testing with the lxcapi_create patchset,
where now killing lxc-create while it was holding the lock did
not lock up future api commands.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
locking: update per Dwight's comment

Create three pairs of functions:
	int process_lock(void);
	void process_unlock(void);
	int container_mem_lock(struct lxc_container *c)
	void container_mem_unlock(struct lxc_container *c)
	int container_disk_lock(struct lxc_container *c);
	void container_disk_unlock(struct lxc_container *c);

and use those in lxccontainer.c

process_lock() is to protect the process state among multiple threads.
container_mem_lock() is to protect a struct container among multiple
threads.  container_disk_lock is to protect a container on disk.

Also remove the lock in lxcapi_init_pid() as Dwight suggested.

Fix a typo (s/container/contain) spotted by Dwight.

More locking fixes are needed, but let's first the the fundamentals
right.  How close does this get us?

Changelog: v2:
	fix lxclock compile

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dwight Engen <dwight.engen@oracle.com>
lxc-stop: use api, remove lxc_shutdown, extend lxc-stop functionality

implement c->reboot(c) in the api.

Also if the container is not running, return -2.  Currently
lxc-stop will return 0, so you cannot tell the difference
between successfull stopping and noop.

Per stgraber's email:

 - Remove lxc-shutdown
 - Change lxc-stop so that:
   * Default behaviour is to call shutdown(), wait 15s for STOPPED, if
not STOPPED, print a message to the user and call stop() [ NOTE:
actually 60 seconds per followup thread]
   * We have a -r option to reboot the container (with proper check that
the container indeed rebooted within the next 15s)
   * We have a -s option to shutdown the container without the automatic
fallback to stop()
   * Add a -k option allowing a user to just kill a container
(equivalent to old lxc-stop, no shutdown() call and no delay).

and update manpages.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
destroy: implement in the api

This requires implementing bdev->ops->destroy() for each of the backing
store types.  Then implementing lxcapi_clone(), writing lxc_destroy.c
using the api, and removing the lxc-destroy.in script.

(this also has a few other cleanups, like marking some functions
static)

Changelog:
	fold into destroy: fix zfs destroy
	destroy: use correct program name in help

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Move container creation fully into the api

1. implement bdev->create:

python and lua: send NULL for bdevtype and bdevspecs.
They'll want to be updated to pass those in in a way that makes
sense, but I can't think about that right now.

2. templates: pass --rootfs

If the container is backed by a device which must be mounted (i.e.
lvm) then pass the actual rootfs mount destination to the
templates.

Note that the lxc.rootfs can be a mounted block device.  The template
should actually be installing the rootfs under the path where the
lxc.rootfs is *mounted*.

Still, some people like to run templates by hand and assume purely
directory backed containers, so continue to support that use case
(i.e. if no --rootfs is listed).

Make sure the templates don't re-write lxc.rootfs if it is
already in the config.  (Most were already checking for that)

3. Replace lxc-create script with lxc_create.c program.

Changelog:
May 24: when creating a container, create $lxcpath/$name/partial,
and flock it.  When done, close that file and unlink it.  In
lxc_container_new() and lxcapi_start(), check for this file.  If
it is locked, create is ongoing.  If it exists but is not locked,
create() was killed - remove the container.

May 24: dont disk-lock during lxcapi_create.  The partial lock
is sufficient.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxc.conf.sgml.in: fill in missing configuration file statements

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
api_clone: call is_stopped_locked() to avoid deadlock.

Technically as Dwight has mentioned we should probably drop the locking
from api_state() altogether, since those are protected through the
lxc command system.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxc.spec.in: remove lxc-shutdown (for commit 3e625e2d)

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxc-console: use fd instead of 0 in setup_tios

We should use the fd specified by caller.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
add console to lxc api

Make lxc_cmd_console() return the fd from the socket connection to the
caller. This fd keeps the tty slot allocated until the caller closes
it. Returning the fd allows for a long lived process to close the fd
and reuse consoles.

Add API function for console allocation.

Create test program for console API.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxccontainer: don't lock around getstate and freeze/unfreeze (v2)

Those go through commands.c and are already mutex'ed that way.

Also remove a unmatched container_disk_unlock in lxcapi_create.

Since is_stopped uses getstate which is no longer locked, rename
it to drop the _locked suffix.

And convert save_config to taking the disk lock.  This way the
save_ and load_config are mutexing each other, as they should.

Changelog: May 29:
   Per Dwight's comment, take the lock before opening the config
      FILE *.
   Only take disklock at load and save_config when we're using the
   container's config file, not when read/writing from/to another
   file.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Dwight Engen <dwight.engen@oracle.com>
waitpid at abort to make sure we can rmdir cgroups

If we abort the container start, and don't wait for the init task to be
reaped after we kill it, then we can't remove the container cgroup
because it is not empty.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxccontainer: update locking comment

Update the LOCKING comment.

Take mem_lock in want_daemonize.

convert lxcapi_destroy to not use privlock/slock by hand.

Fix a coverity-found potential dereference of NULL c->lxc_conf.

api_cgroup_get_item() and api_cgroup_set_item(): use disklock,
not memlock, since the values are set through the cgroup fs on
the running container.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
configure/makefile: rename default_conf to distro_conf

configure/makefile: rename default_conf to distro_conf, since it is a per-distro
default.  Then we'll be able to use the symbol LXC_DEFAULT_CONF in the code to
refer to the installed file.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Define LXC_DEFAULT_CONFIG

And use it in place of the various ways we were deducing /etc/lxc/default.conf.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
lxc-alpine: download a static package manager if its missing

If the package manager, apk-tools is missing, then:
 - download a static binary and public keys
 - verify the keys against embedded checksum
 - verify the signature of the static binary against the downloaded keys
 - use the verified static binary

Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
lxcapi_create: don't close stdin/out/err

Otherwise we can't see template progress.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
arguments: should return negative number when error happens

We should return -ENOMEM instead of ENOMEM when realloc fails.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>