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

Macros
#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. More...
int	lxclock (struct lxc_lock *lock, int timeout)
	Take an existing lock. More...
int	lxcunlock (struct lxc_lock *lock)
	Unlock specified lock previously locked using lxclock(). More...
void	lxc_putlock (struct lxc_lock *lock)
	Free a lock created by lxc_newlock(). More...
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. More...
void	container_mem_unlock (struct lxc_container *c)
	Unlock the containers memory. More...
int	container_disk_lock (struct lxc_container *c)
	Lock the containers disk data. More...
void	container_disk_unlock (struct lxc_container *c)
	Unlock the containers disk data. More...

Detailed Description

liblxcapi

Copyright © 2012 Serge Hallyn serge.nosp@m..hal.nosp@m.lyn@u.nosp@m.bunt.nosp@m.u.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

Macro Definition 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
	)

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.