path: root/fs/hppfs/hppfs_kern.c

/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <linux/ctype.h>
#include <linux/dcache.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/slab.h>
#include <linux/statfs.h>
#include <linux/types.h>
#include <asm/uaccess.h>
#include "os.h"

static struct inode *get_inode(struct super_block *, struct dentry *);

struct hppfs_data {
	struct list_head list;
	char contents[PAGE_SIZE - sizeof(struct list_head)];
};

struct hppfs_private {
	struct file *proc_file;
	int host_fd;
	loff_t len;
	struct hppfs_data *contents;
};

struct hppfs_inode_info {
	struct dentry *proc_dentry;
	struct inode vfs_inode;
};

static inline struct hppfs_inode_info *HPPFS_I(struct inode *inode)
{
	return container_of(inode, struct hppfs_inode_info, vfs_inode);
}

#define HPPFS_SUPER_MAGIC 0xb00000ee

static const struct super_operations hppfs_sbops;

static int is_pid(struct dentry *dentry)
{
	struct super_block *sb;
	int i;

	sb = dentry->d_sb;
	if (dentry->d_parent != sb->s_root)
		return 0;

	for (i = 0; i < dentry->d_name.len; i++) {
		if (!isdigit(dentry->d_name.name[i]))
			return 0;
	}
	return 1;
}

static char *dentry_name(struct dentry *dentry, int extra)
{
	struct dentry *parent;
	char *root, *name;
	const char *seg_name;
	int len, seg_len;

	len = 0;
	parent = dentry;
	while (parent->d_parent != parent) {
		if (is_pid(parent))
			len += strlen("pid") + 1;
		else len += parent->d_name.len + 1;
		parent = parent->d_parent;
	}

	root = "proc";
	len += strlen(root);
	name = kmalloc(len + extra + 1, GFP_KERNEL);
	if (name == NULL)
		return NULL;

	name[len] = '\0';
	parent = dentry;
	while (parent->d_parent != parent) {
		if (is_pid(parent)) {
			seg_name = "pid";
			seg_len = strlen("pid");
		}
		else {
			seg_name = parent->d_name.name;
			seg_len = parent->d_name.len;
		}

		len -= seg_len + 1;
		name[len] = '/';
		strncpy(&name[len + 1], seg_name, seg_len);
		parent = parent->d_parent;
	}
	strncpy(name, root, strlen(root));
	return name;
}

static int file_removed(struct dentry *dentry, const char *file)
{
	char *host_file;
	int extra, fd;

	extra = 0;
	if (file != NULL)
		extra += strlen(file) + 1;

	host_file = dentry_name(dentry, extra + strlen("/remove"));
	if (host_file == NULL) {
		printk(KERN_ERR "file_removed : allocation failed\n");
		return -ENOMEM;
	}

	if (file != NULL) {
		strcat(host_file, "/");
		strcat(host_file, file);
	}
	strcat(host_file, "/remove");

	fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
	kfree(host_file);
	if (fd > 0) {
		os_close_file(fd);
		return 1;
	}
	return 0;
}

static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
				   struct nameidata *nd)
{
	struct dentry *proc_dentry, *new, *parent;
	struct inode *inode;
	int err, deleted;

	deleted = file_removed(dentry, NULL);
	if (deleted < 0)
		return ERR_PTR(deleted);
	else if (deleted)
		return ERR_PTR(-ENOENT);

	err = -ENOMEM;
	parent = HPPFS_I(ino)->proc_dentry;
	mutex_lock(&parent->d_inode->i_mutex);
	proc_dentry = d_lookup(parent, &dentry->d_name);
	if (proc_dentry == NULL) {
		proc_dentry = d_alloc(parent, &dentry->d_name);
		if (proc_dentry == NULL) {
			mutex_unlock(&parent->d_inode->i_mutex);
			goto out;
		}
		new = (*parent->d_inode->i_op->lookup)(parent->d_inode,
						       proc_dentry, NULL);
		if (new) {
			dput(proc_dentry);
			proc_dentry = new;
		}
	}
	mutex_unlock(&parent->d_inode->i_mutex);

	if (IS_ERR(proc_dentry))
		return proc_dentry;

	err = -ENOMEM;
	inode = get_inode(ino->i_sb, proc_dentry);
	if (!inode)
		goto out_dput;

 	d_add(dentry, </