inode.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

			save_and_cli (flags);
			error = prom_setprop (node, op->name,
					      op->value, op->len + 1);
			restore_flags (flags);
			if (error <= 0)
				printk (KERN_WARNING "openpromfs: "
					"Couldn't write property %s\n",
					op->name);
		} else if ((op->flag & OPP_BINARY) || !op->len) {
			save_and_cli (flags);
			error = prom_setprop (node, op->name,
					      op->value, op->len);
			restore_flags (flags);
			if (error <= 0)
				printk (KERN_WARNING "openpromfs: "
					"Couldn't write property %s\n",
					op->name);
		} else {
			printk (KERN_WARNING "openpromfs: "
				"Unknown property type of %s\n",
				op->name);
		}
	}
	unlock_kernel();
	kfree (filp->private_data);
	return 0;
}

static struct file_operations openpromfs_prop_ops = {
	read:		property_read,
	write:		property_write,
	release:	property_release,
};

static struct file_operations openpromfs_nodenum_ops = {
	read:		nodenum_read,
};

static struct file_operations openprom_operations = {
	read:		generic_read_dir,
	readdir:	openpromfs_readdir,
};

static struct inode_operations openprom_alias_inode_operations = {
	create:		openpromfs_create,
	lookup:		openpromfs_lookup,
	unlink:		openpromfs_unlink,
};

static struct inode_operations openprom_inode_operations = {
	lookup:		openpromfs_lookup,
};

static int lookup_children(u16 n, const char * name, int len)
{
	int ret;
	u16 node;
	for (; n != 0xffff; n = nodes[n].next) {
		node = nodes[n].child;
		if (node != 0xffff) {
			char buffer[128];
			int i;
			char *p;
			
			while (node != 0xffff) {
				if (prom_getname (nodes[node].node,
						  buffer, 128) >= 0) {
					i = strlen (buffer);
					if ((len == i)
					    && !strncmp (buffer, name, len))
						return NODE2INO(node);
					p = strchr (buffer, '@');
					if (p && (len == p - buffer)
					    && !strncmp (buffer, name, len))
						return NODE2INO(node);
				}
				node = nodes[node].next;
			}
		} else
			continue;
		ret = lookup_children (nodes[n].child, name, len);
		if (ret) return ret;
	}
	return 0;
}

static struct dentry *openpromfs_lookup(struct inode * dir, struct dentry *dentry)
{
	int ino = 0;
#define OPFSL_DIR	0
#define OPFSL_PROPERTY	1
#define OPFSL_NODENUM	2
	int type = 0;
	char buffer[128];
	char *p;
	const char *name;
	u32 n;
	u16 dirnode;
	unsigned int len;
	int i;
	struct inode *inode;
	char buffer2[64];
	
	inode = NULL;
	name = dentry->d_name.name;
	len = dentry->d_name.len;
	if (name [0] == '.' && len == 5 && !strncmp (name + 1, "node", 4)) {
		ino = NODEP2INO(NODE(dir->i_ino).first_prop);
		type = OPFSL_NODENUM;
	}
	if (!ino) {
		u16 node = NODE(dir->i_ino).child;
		while (node != 0xffff) {
			if (prom_getname (nodes[node].node, buffer, 128) >= 0) {
				i = strlen (buffer);
				if (len == i && !strncmp (buffer, name, len)) {
					ino = NODE2INO(node);
					type = OPFSL_DIR;
					break;
				}
				p = strchr (buffer, '@');
				if (p && (len == p - buffer)
				    && !strncmp (buffer, name, len)) {
					ino = NODE2INO(node);
					type = OPFSL_DIR;
					break;
				}
			}
			node = nodes[node].next;
		}
	}
	n = NODE(dir->i_ino).node;
	dirnode = dir->i_ino - OPENPROM_FIRST_INO;
	if (!ino) {
		int j = NODEP2INO(NODE(dir->i_ino).first_prop);
		if (dirnode != aliases) {
			for (p = prom_firstprop (n, buffer2);
			     p && *p;
			     p = prom_nextprop (n, p, buffer2)) {
				j++;
				if ((len == strlen (p))
				    && !strncmp (p, name, len)) {
					ino = j;
					type = OPFSL_PROPERTY;
					break;
				}
			}
		} else {
			int k;
			for (k = 0; k < aliases_nodes; k++) {
				j++;
				if (alias_names [k]
				    && (len == strlen (alias_names [k]))
				    && !strncmp (alias_names [k], name, len)) {
					ino = j;
					type = OPFSL_PROPERTY;
					break;
				}
			}
		}
	}
	if (!ino) {
		ino = lookup_children (NODE(dir->i_ino).child, name, len);
		if (ino)
			type = OPFSL_DIR;
		else
			return ERR_PTR(-ENOENT);
	}
	inode = iget (dir->i_sb, ino);
	if (!inode)
		return ERR_PTR(-EINVAL);
	switch (type) {
	case OPFSL_DIR:
		inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
		if (ino == OPENPROM_FIRST_INO + aliases) {
			inode->i_mode |= S_IWUSR;
			inode->i_op = &openprom_alias_inode_operations;
		} else
			inode->i_op = &openprom_inode_operations;
		inode->i_fop = &openprom_operations;
		inode->i_nlink = 2;
		break;
	case OPFSL_NODENUM:
		inode->i_mode = S_IFREG | S_IRUGO;
		inode->i_fop = &openpromfs_nodenum_ops;
		inode->i_nlink = 1;
		inode->u.generic_ip = (void *)(long)(n);
		break;
	case OPFSL_PROPERTY:
		if ((dirnode == options) && (len == 17)
		    && !strncmp (name, "security-password", 17))
			inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
		else {
			inode->i_mode = S_IFREG | S_IRUGO;
			if (dirnode == options || dirnode == aliases) {
				if (len != 4 || strncmp (name, "name", 4))
					inode->i_mode |= S_IWUSR;
			}
		}
		inode->i_fop = &openpromfs_prop_ops;
		inode->i_nlink = 1;
		if (inode->i_size < 0)
			inode->i_size = 0;
		inode->u.generic_ip = (void *)(long)(((u16)dirnode) | 
			(((u16)(ino - NODEP2INO(NODE(dir->i_ino).first_prop) - 1)) << 16));
		break;
	}

	inode->i_gid = 0;
	inode->i_uid = 0;

	d_add(dentry, inode);
	return NULL;
}

static int openpromfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
	struct inode *inode = filp->f_dentry->d_inode;
	unsigned int ino;
	u32 n;
	int i, j;
	char buffer[128];
	u16 node;
	char *p;
	char buffer2[64];
	
	ino = inode->i_ino;
	i = filp->f_pos;
	switch (i) {
	case 0:
		if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) return 0;
		i++;
		filp->f_pos++;
		/* fall thru */
	case 1:
		if (filldir(dirent, "..", 2, i, 
			(NODE(ino).parent == 0xffff) ? 
			OPENPROM_ROOT_INO : NODE2INO(NODE(ino).parent), DT_DIR) < 0) 
			return 0;
		i++;
		filp->f_pos++;
		/* fall thru */
	default:
		i -= 2;
		node = NODE(ino).child;
		while (i && node != 0xffff) {
			node = nodes[node].next;
			i--;
		}
		while (node != 0xffff) {
			if (prom_getname (nodes[node].node, buffer, 128) < 0)
				return 0;
			if (filldir(dirent, buffer, strlen(buffer),
				    filp->f_pos, NODE2INO(node), DT_DIR) < 0)
				return 0;
			filp->f_pos++;
			node = nodes[node].next;
		}
		j = NODEP2INO(NODE(ino).first_prop);
		if (!i) {
			if (filldir(dirent, ".node", 5, filp->f_pos, j, DT_REG) < 0)
				return 0;
			filp->f_pos++;
		} else
			i--;
		n = NODE(ino).node;
		if (ino == OPENPROM_FIRST_INO + aliases) {
			for (j++; i < aliases_nodes; i++, j++) {
				if (alias_names [i]) {
					if (filldir (dirent, alias_names [i], 
						strlen (alias_names [i]), 
						filp->f_pos, j, DT_REG) < 0) return 0;
					filp->f_pos++;
				}
			}
		} else {
			for (p = prom_firstprop (n, buffer2);
			     p && *p;
			     p = prom_nextprop (n, p, buffer2)) {
				j++;
				if (i) i--;
				else {
					if (filldir(dirent, p, strlen(p),
						    filp->f_pos, j, DT_REG) < 0)
						return 0;
					filp->f_pos++;
				}
			}
		}
	}
	return 0;
}

static int openpromfs_create (struct inode *dir, struct dentry *dentry, int mode)
{
	char *p;
	struct inode *inode;
	
	if (!dir)
		return -ENOENT;
	if (dentry->d_name.len > 256)
		return -EINVAL;
	if (aliases_nodes == ALIASES_NNODES)
		return -EIO;
	p = kmalloc (dentry->d_name.len + 1, GFP_KERNEL);
	if (!p)
		return -ENOMEM;
	strncpy (p, dentry->d_name.name, dentry->d_name.len);
	p [dentry->d_name.len] = 0;
	alias_names [aliases_nodes++] = p;
	inode = iget (dir->i_sb,
			NODEP2INO(NODE(dir->i_ino).first_prop) + aliases_nodes);
	if (!inode)
		return -EINVAL;
	inode->i_mode = S_IFREG | S_IRUGO | S_IWUSR;
	inode->i_fop = &openpromfs_prop_ops;
	inode->i_nlink = 1;
	if (inode->i_size < 0) inode->i_size = 0;
	inode->u.generic_ip = (void *)(long)(((u16)aliases) | 
			(((u16)(aliases_nodes - 1)) << 16));
	d_instantiate(dentry, inode);
	return 0;
}

static int openpromfs_unlink (struct inode *dir, struct dentry *dentry)
{
	unsigned int len;
	char *p;
	const char *name;
	int i;
	
	name = dentry->d_name.name;
	len = dentry->d_name.len;
	for (i = 0; i < aliases_nodes; i++)
		if ((strlen (alias_names [i]) == len)
		    && !strncmp (name, alias_names[i], len)) {
			char buffer[512];
			
			p = alias_names [i];
			alias_names [i] = NULL;
			kfree (p);
			strcpy (buffer, "nvunalias ");
			memcpy (buffer + 10, name, len);
			buffer [10 + len] = 0;
			prom_feval (buffer);
		}
	return 0;
}

/* {{{ init section */
#ifndef MODULE
static int __init check_space (u16 n)
#else
static int check_space (u16 n)
#endif
{
	unsigned long pages;

	if ((1 << alloced) * PAGE_SIZE < (n + 2) * sizeof(openpromfs_node)) {
		pages = __get_free_pages (GFP_KERNEL, alloced + 1);
		if (!pages)
			return -1;

		if (nodes) {
			memcpy ((char *)pages, (char *)nodes,
				(1 << alloced) * PAGE_SIZE);
			free_pages ((unsigned long)nodes, alloced);
		}
		alloced++;
		nodes = (openpromfs_node *)pages;
	}
	return 0;
}

#ifndef MODULE
static u16 __init get_nodes (u16 parent, u32 node)
#else
static u16 get_nodes (u16 parent, u32 node)
#endif
{
	char *p;
	u16 n = last_node++, i;
	char buffer[64];

	if (check_space (n) < 0)
		return 0xffff;
	nodes[n].parent = parent;
	nodes[n].node = node;
	nodes[n].next = 0xffff;
	nodes[n].child = 0xffff;
	nodes[n].first_prop = first_prop++;
	if (!parent) {
		char buffer[8];
		int j;
		
		if ((j = prom_getproperty (node, "name", buffer, 8)) >= 0) {
		    buffer[j] = 0;
		    if (!strcmp (buffer, "options"))
			options = n;
		    else if (!strcmp (buffer, "aliases"))
		        aliases = n;
		}
	}
	if (n != aliases)
		for (p = prom_firstprop (node, buffer);
		     p && p != (char *)-1 && *p;
		     p = prom_nextprop (node, p, buffer))
			first_prop++;
	else {
		char *q;
		for (p = prom_firstprop (node, buffer);
		     p && p != (char *)-1 && *p;
		     p = prom_nextprop (node, p, buffer)) {
			if (aliases_nodes == ALIASES_NNODES)
				break;
			for (i = 0; i < aliases_nodes; i++)
				if (!strcmp (p, alias_names [i]))
					break;
			if (i < aliases_nodes)
				continue;
			q = kmalloc (strlen (p) + 1, GFP_KERNEL);
			if (!q)
				return 0xffff;
			strcpy (q, p);
			alias_names [aliases_nodes++] = q;
		}
		first_prop += ALIASES_NNODES;
	}
	node = prom_getchild (node);
	if (node) {
		parent = get_nodes (n, node);
		if (parent == 0xffff)
			return 0xffff;
		nodes[n].child = parent;
		while ((node = prom_getsibling (node)) != 0) {
			i = get_nodes (n, node);
			if (i == 0xffff)
				return 0xffff;
			nodes[parent].next = i;
			parent = i;
		}
	}
	return n;
}

static void openprom_read_inode(struct inode * inode)
{
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	if (inode->i_ino == OPENPROM_ROOT_INO) {
		inode->i_op = &openprom_inode_operations;
		inode->i_fop = &openprom_operations;
		inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
	}
}

static int openprom_statfs(struct super_block *sb, struct statfs *buf)
{
	buf->f_type = OPENPROM_SUPER_MAGIC;
	buf->f_bsize = PAGE_SIZE/sizeof(long);	/* ??? */
	buf->f_bfree = 0;
	buf->f_bavail = 0;
	buf->f_ffree = 0;
	buf->f_namelen = NAME_MAX;
	return 0;
}

static struct super_operations openprom_sops = { 
	read_inode:	openprom_read_inode,
	statfs:		openprom_statfs,
};

struct super_block *openprom_read_super(struct super_block *s,void *data, 
				    int silent)
{
	struct inode * root_inode;

	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = OPENPROM_SUPER_MAGIC;
	s->s_op = &openprom_sops;
	root_inode = iget(s, OPENPROM_ROOT_INO);
	if (!root_inode)
		goto out_no_root;
	s->s_root = d_alloc_root(root_inode);
	if (!s->s_root)
		goto out_no_root;
	return s;

out_no_root:
	printk("openprom_read_super: get root inode failed\n");
	iput(root_inode);
	return NULL;
}

static DECLARE_FSTYPE(openprom_fs_type, "openpromfs", openprom_read_super, 0);

static int __init init_openprom_fs(void)
{
	nodes = (openpromfs_node *)__get_free_pages(GFP_KERNEL, 0);
	if (!nodes) {
		printk (KERN_WARNING "openpromfs: can't get free page\n");
		return -EIO;
	}
	if (get_nodes (0xffff, prom_root_node) == 0xffff) {
		printk (KERN_WARNING "openpromfs: couldn't setup tree\n");
		return -EIO;
	}
	nodes[last_node].first_prop = first_prop;
	return register_filesystem(&openprom_fs_type);
}

static void __exit exit_openprom_fs(void)
{
	int i;
	unregister_filesystem(&openprom_fs_type);
	free_pages ((unsigned long)nodes, alloced);
	for (i = 0; i < aliases_nodes; i++)
		if (alias_names [i])
			kfree (alias_names [i]);
	nodes = NULL;
}

EXPORT_NO_SYMBOLS;

module_init(init_openprom_fs)
module_exit(exit_openprom_fs)
MODULE_LICENSE("GPL");