C++ seq_open函数代码示例

static int crypto_info_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &crypto_seq_ops);
}

/*
 *  Now to implement the /proc file we need only make an open
 *  method which sets up the sequence operators.
 *  */
static int socle_otg_proc_open(struct inode *inode, struct file *file)
{
     return seq_open(file, &socle_otg_seq_ops);
}

/**
 * This function is called when the /proc file is open.
 *
 */
static int my_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &my_seq_ops);
};

static int slabinfo_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &slabinfo_op);
}

//.........这里部分代码省略.........
	struct nsproxy *nsp;
	struct mnt_namespace *ns = NULL;
	struct path root;
	struct proc_mounts *p;
	int ret = -EINVAL;

	if (!task)
		goto err;

	task_lock(task);
	nsp = task->nsproxy;
	if (!nsp || !nsp->mnt_ns) {
		task_unlock(task);
		put_task_struct(task);
		goto err;
	}
	ns = nsp->mnt_ns;
	get_mnt_ns(ns);
	if (!task->fs) {
		task_unlock(task);
		put_task_struct(task);
		ret = -ENOENT;
		goto err_put_ns;
	}
	get_fs_root(task->fs, &root);
	task_unlock(task);
	put_task_struct(task);

	ret = -ENOMEM;
	p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
	if (!p)
		goto err_put_path;

	file->private_data = &p->m;
	ret = seq_open(file, &mounts_op);
	if (ret)
		goto err_free;

	p->ns = ns;
	p->root = root;
	p->m.poll_event = ns->event;
	p->show = show;

	return 0;

 err_free:
	kfree(p);
 err_put_path:
	path_put(&root);
 err_put_ns:
	put_mnt_ns(ns);
 err:
	return ret;
}

static int mounts_release(struct inode *inode, struct file *file)
{
	struct proc_mounts *p = proc_mounts(file->private_data);
	path_put(&p->root);
	put_mnt_ns(p->ns);
	return seq_release(inode, file);
}

static int mounts_open(struct inode *inode, struct file *file)
{
	return mounts_open_common(inode, file, show_vfsmnt);
}

static int mountinfo_open(struct inode *inode, struct file *file)
{
	return mounts_open_common(inode, file, show_mountinfo);
}

static int mountstats_open(struct inode *inode, struct file *file)
{
	return mounts_open_common(inode, file, show_vfsstat);
}

const struct file_operations proc_mounts_operations = {
	.open		= mounts_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
	.poll		= mounts_poll,
};

const struct file_operations proc_mountinfo_operations = {
	.open		= mountinfo_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
	.poll		= mounts_poll,
};

const struct file_operations proc_mountstats_operations = {
	.open		= mountstats_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
};

static int partitions_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &partitions_op);
}

static int yam_info_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &yam_seqops);
}

static int log_proc_open(struct inode *inode, struct file *file)
{
	if( htc_monitor_param == 0 )
		return -EPERM;
	return seq_open(file, &log_seq_ops);
}

static int proc_nommu_region_list_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &proc_nommu_region_list_seqop);
}

static int atm_dev_seq_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &atm_dev_seq_ops);
}

/*
 * open "/proc/fs/fscache/histogram" to provide latency data
 */
static int fscache_histogram_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &fscache_histogram_ops);
}

static int profiling_events_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &profiling_events_seq_ops);
}

static int devinfo_open(struct inode *inode, struct file *filp)
{
	return seq_open(filp, &devinfo_ops);
}

static int proc_tty_ldiscs_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &tty_ldiscs_seq_ops);
}

static int rxrpc_call_seq_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &rxrpc_call_seq_ops);
}