lxclock.h File Reference

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <semaphore.h>
#include <string.h>
#include <time.h>

Include dependency graph for lxclock.h:

Go to the source code of this file.

Data Structures
struct	lxc_lock
Defines
#define	LXC_LOCK_ANON_SEM   1
#define	LXC_LOCK_FLOCK   2
Functions
struct lxc_lock *	lxc_newlock (const char *lxcpath, const char *name)
	Create a new (unlocked) lock.
int	lxclock (struct lxc_lock *lock, int timeout)
	Take an existing lock.
int	lxcunlock (struct lxc_lock *lock)
	Unlock specified lock previously locked using lxclock().
void	lxc_putlock (struct lxc_lock *lock)
	Free a lock created by lxc_newlock().
void	process_lock (void)
	Lock the current process.
void	process_unlock (void)
	Unlock the current process.
int	container_mem_lock (struct lxc_container *c)
	Lock the containers memory.
void	container_mem_unlock (struct lxc_container *c)
	Unlock the containers memory.
int	container_disk_lock (struct lxc_container *c)
	Lock the containers disk data.
void	container_disk_unlock (struct lxc_container *c)
	Unlock the containers disk data.

---

Detailed Description

liblxcapi

Copyright © 2012 Serge Hallyn <serge.hallyn@ubuntu.com>. Copyright © 2012 Canonical Ltd.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

---

Define Documentation

#define LXC_LOCK_ANON_SEM   1

Anonymous semaphore lock

#define LXC_LOCK_FLOCK   2

flock(2) lock

---

Function Documentation

int container_disk_lock

(

struct lxc_container *

c

)

Lock the containers disk data.

Parameters:

c

Container.

Returns:

0 on success, or an lxclock() error return values on error.

void container_disk_unlock

(

struct lxc_container *

c

)

Unlock the containers disk data.

Parameters:

c

Container.

int container_mem_lock

(

struct lxc_container *

c

)

Lock the containers memory.

Parameters:

c

Container.

Returns:

As for lxclock().

void container_mem_unlock

(

struct lxc_container *

c

)

Unlock the containers memory.

Parameters:

c

Container.

struct lxc_lock* lxc_newlock	(	const char *	lxcpath,
		const char *	name
	)			[read]

Create a new (unlocked) lock.

Parameters:

	lxcpath	lxcpath lock should relate to.
	name	Name for lock.

Returns:

Newly-allocated lxclock on success, NULL on failure.

Note:

If name is not given, create an unnamed semaphore (used to protect against racing threads).

Note that an unnamed sem was malloced by us and needs to be freed.

void lxc_putlock

(

struct lxc_lock *

lock

)

Free a lock created by lxc_newlock().

Parameters:

lock

Lock.

int lxclock	(	struct lxc_lock *	lock,
		int	timeout
	)

Take an existing lock.

Parameters:

	lock	Lock to operate on.
	timeout	Seconds to wait to take lock (0 signifies an indefinite wait).

Returns:

0 if lock obtained, -2 on failure to set timeout, or -1 on any other error (errno will be set by sem_wait(3) or fcntl(2)).

Note:

timeout is (currently?) only supported for privlock, not for slock. Since currently there is not a single use of the timeout (except in the test case) I may remove the support for it in sem as well.

int lxcunlock

(

struct lxc_lock *

lock

)

Unlock specified lock previously locked using lxclock().

Parameters:

lock

lxc_lock.

Returns:

0 on success, -2 if provided lock was not already held, otherwise -1 with errno saved from fcntl(2) or sem_post function.