path: root/ipc/mqueue.c

/*
 * POSIX message queues filesystem for Linux.
 *
 * Copyright (C) 2003,2004  Krzysztof Benedyczak    (golbi@mat.uni.torun.pl)
 *                          Michal Wronski          (michal.wronski@gmail.com)
 *
 * Spinlocks:               Mohamed Abbas           (abbas.mohamed@intel.com)
 * Lockless receive & send, fd based notify:
 * 			    Manfred Spraul	    (manfred@colorfullife.com)
 *
 * Audit:                   George Wilson           (ltcgcw@us.ibm.com)
 *
 * This file is released under the GPL.
 */

#include <linux/capability.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/sysctl.h>
#include <linux/poll.h>
#include <linux/mqueue.h>
#include <linux/msg.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/signal.h>
#include <linux/mutex.h>

#include <net/sock.h>
#include "util.h"

#define MQUEUE_MAGIC	0x19800202
#define DIRENT_SIZE	20
#define FILENT_SIZE	80

#define SEND		0
#define RECV		1

#define STATE_NONE	0
#define STATE_PENDING	1
#define STATE_READY	2

/* used by sysctl */
#define FS_MQUEUE 	1
#define CTL_QUEUESMAX 	2
#define CTL_MSGMAX 	3
#define CTL_MSGSIZEMAX 	4

/* default values */
#define DFLT_QUEUESMAX	256	/* max number of message queues */
#define DFLT_MSGMAX 	10	/* max number of messages in each queue */
#define HARD_MSGMAX 	(131072/sizeof(void*))
#define DFLT_MSGSIZEMAX 8192	/* max message size */


struct ext_wait_queue {		/* queue of sleeping tasks */
	struct task_struct *task;
	struct list_head list;
	struct msg_msg *msg;	/* ptr of loaded message */
	int state;		/* one of STATE_* values */
};

struct mqueue_inode_info {
	spinlock_t lock;
	struct inode vfs_inode;
	wait_queue_head_t wait_q;

	struct msg_msg **messages;
	struct mq_attr attr;

	struct sigevent notify;
	struct pid* notify_owner;
	struct user_struct *user;	/* user who created, for accounting */
	struct sock *notify_sock;
	struct sk_buff *notify_cookie;

	/* for tasks waiting for free space and messages, respectively */
	struct ext_wait_queue e_wait_q[2];

	unsigned long qsize; /* size of queue in memory (sum of all msgs) */
};

static struct inode_operations mqueue_dir_inode_operations;
static struct file_operations mqueue_file_operations;
static struct super_operations mqueue_super_ops;
static void remove_notification(struct mqueue_inode_info *info);

static spinlock_t mq_lock;
static kmem_cache_t *mqueue_inode_cachep;
static struct vfsmount *mqueue_mnt;

static unsigned int queues_count;
static unsigned int queues_max 	= DFLT_QUEUESMAX;
static unsigned int msg_max 	= DFLT_MSGMAX;
static unsigned int msgsize_max = DFLT_MSGSIZEMAX;

static struct ctl_table_header * mq_sysctl_table;

static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
{
	return container_of(inode, struct mqueue_inode_info, vfs_inode);
}

static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
							struct mq_attr *attr)
{
	struct inode *inode;

	inode = new_inode(