integrity: IMA policy open

static struct dentry *violations;

static struct dentry *ima_policy;

static atomic_t policy_opencount = ATOMIC_INIT(1);

/*

 * ima_open_policy: sequentialize access to the policy file

 */

int ima_open_policy(struct inode * inode, struct file * filp)

{

	if (atomic_dec_and_test(&policy_opencount))

		return 0;

	return -EBUSY;

}

/*

 * ima_release_policy - start using the new measure policy rules.

 *

 * Initially, ima_measure points to the default policy rules, now

 * point to the new policy rules, and remove the securityfs policy file.

 * point to the new policy rules, and remove the securityfs policy file,

 * assuming a valid policy.

 */

static int ima_release_policy(struct inode *inode, struct file *file)

{

	if (!valid_policy) {

		ima_delete_rules();

		valid_policy = 1;

		atomic_set(&policy_opencount, 1);

		return 0;

	}

	ima_update_policy();

}

static struct file_operations ima_measure_policy_ops = {

	.open = ima_open_policy,

	.write = ima_write_policy,

	.release = ima_release_policy

};