hppfs_kern.c

linux 内核源代码

/*
 * Copyright (C) 2002 Jeff Dike ([e-mail])
 * Licensed under the GPL
 */

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

static int init_inode(struct inode *inode, struct dentry *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((sb->s_op != &hppfs_sbops) || (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);
}

struct dentry_operations hppfs_dentry_ops = {
};

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("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 void hppfs_read_inode(struct inode *ino)
{
	struct inode *proc_ino;

	if(HPPFS_I(ino)->proc_dentry == NULL)
		return;

	proc_ino = HPPFS_I(ino)->proc_dentry->d_inode;
	ino->i_uid = proc_ino->i_uid;
	ino->i_gid = proc_ino->i_gid;
	ino->i_atime = proc_ino->i_atime;
	ino->i_mtime = proc_ino->i_mtime;
	ino->i_ctime = proc_ino->i_ctime;
	ino->i_ino = proc_ino->i_ino;
	ino->i_mode = proc_ino->i_mode;
	ino->i_nlink = proc_ino->i_nlink;
	ino->i_size = proc_ino->i_size;
	ino->i_blocks = proc_ino->i_blocks;
}

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);

	inode = iget(ino->i_sb, 0);
	if(inode == NULL)
		goto out_dput;

	err = init_inode(inode, proc_dentry);
	if(err)
		goto out_put;

	hppfs_read_inode(inode);

 	d_add(dentry, inode);
	dentry->d_op = &hppfs_dentry_ops;
	return(NULL);

 out_put:
	iput(inode);
 out_dput:
	dput(proc_dentry);
 out:
	return(ERR_PTR(err));
}

static const struct inode_operations hppfs_file_iops = {
};

static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
			 loff_t *ppos, int is_user)
{
	ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
	ssize_t n;

	read = file->f_path.dentry->d_inode->i_fop->read;

	if(!is_user)
		set_fs(KERNEL_DS);

	n = (*read)(file, buf, count, &file->f_pos);

	if(!is_user)
		set_fs(USER_DS);

	if(ppos) *ppos = file->f_pos;
	return n;
}

static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
{
	ssize_t n;
	int cur, err;
	char *new_buf;

	n = -ENOMEM;
	new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if(new_buf == NULL){
		printk("hppfs_read_file : kmalloc failed\n");
		goto out;
	}
	n = 0;
	while(count > 0){
		cur = min_t(ssize_t, count, PAGE_SIZE);
		err = os_read_file(fd, new_buf, cur);
		if(err < 0){
			printk("hppfs_read : read failed, errno = %d\n",
			       err);
			n = err;
			goto out_free;
		}
		else if(err == 0)
			break;

		if(copy_to_user(buf, new_buf, err)){
			n = -EFAULT;
			goto out_free;
		}
		n += err;
		count -= err;
	}
 out_free:
	kfree(new_buf);
 out:
	return n;
}

static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
			  loff_t *ppos)
{
	struct hppfs_private *hppfs = file->private_data;
	struct hppfs_data *data;
	loff_t off;
	int err;

	if(hppfs->contents != NULL){
		if(*ppos >= hppfs->len) return(0);

		data = hppfs->contents;
		off = *ppos;
		while(off >= sizeof(data->contents)){
			data = list_entry(data->list.next, struct hppfs_data,
					  list);
			off -= sizeof(data->contents);
		}

		if(off + count > hppfs->len)
			count = hppfs->len - off;
		copy_to_user(buf, &data->contents[off], count);
		*ppos += count;
	}
	else if(hppfs->host_fd != -1){
		err = os_seek_file(hppfs->host_fd, *ppos);
		if(err){
			printk("hppfs_read : seek failed, errno = %d\n", err);
			return(err);
		}
		count = hppfs_read_file(hppfs->host_fd, buf, count);
		if(count > 0)
			*ppos += count;
	}
	else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);

	return(count);
}

static ssize_t hppfs_write(struct file *file, const char __user *buf, size_t len,
			   loff_t *ppos)
{
	struct hppfs_private *data = file->private_data;
	struct file *proc_file = data->proc_file;
	ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
	int err;

	write = proc_file->f_path.dentry->d_inode->i_fop->write;

	proc_file->f_pos = file->f_pos;
	err = (*write)(proc_file, buf, len, &proc_file->f_pos);
	file->f_pos = proc_file->f_pos;

	return(err);
}

static int open_host_sock(char *host_file, int *filter_out)
{
	char *end;
	int fd;

	end = &host_file[strlen(host_file)];
	strcpy(end, "/rw");
	*filter_out = 1;
	fd = os_connect_socket(host_file);
	if(fd > 0)
		return(fd);

	strcpy(end, "/r");
	*filter_out = 0;
	fd = os_connect_socket(host_file);
	return(fd);
}

static void free_contents(struct hppfs_data *head)
{
	struct hppfs_data *data;
	struct list_head *ele, *next;

	if(head == NULL) return;

	list_for_each_safe(ele, next, &head->list){
		data = list_entry(ele, struct hppfs_data, list);
		kfree(data);
	}
	kfree(head);
}

static struct hppfs_data *hppfs_get_data(int fd, int filter,
					 struct file *proc_file,
					 struct file *hppfs_file,
					 loff_t *size_out)
{
	struct hppfs_data *data, *new, *head;
	int n, err;

	err = -ENOMEM;
	data = kmalloc(sizeof(*data), GFP_KERNEL);
	if(data == NULL){
		printk("hppfs_get_data : head allocation failed\n");
		goto failed;
	}

	INIT_LIST_HEAD(&data->list);

	head = data;
	*size_out = 0;

	if(filter){
		while((n = read_proc(proc_file, data->contents,
				     sizeof(data->contents), NULL, 0)) > 0)
			os_write_file(fd, data->contents, n);
		err = os_shutdown_socket(fd, 0, 1);
		if(err){
			printk("hppfs_get_data : failed to shut down "
			       "socket\n");
			goto failed_free;
		}
	}
	while(1){
		n = os_read_file(fd, data->contents, sizeof(data->contents));
		if(n < 0){
			err = n;
			printk("hppfs_get_data : read failed, errno = %d\n",
			       err);
			goto failed_free;
		}
		else if(n == 0)
			break;