Fixed MTP to work with TWRP

fs/openpromfs/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the Linux Sun Openprom filesystem routines.
+#
+
+obj-$(CONFIG_SUN_OPENPROMFS) += openpromfs.o
+
+openpromfs-objs := inode.o

fs/openpromfs/inode.c

@@ -0,0 +1,471 @@
+/* inode.c: /proc/openprom handling routines
+ *
+ * Copyright (C) 1996-1999 Jakub Jelinek  (jakub@redhat.com)
+ * Copyright (C) 1998      Eddie C. Dost  (ecd@skynet.be)
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/magic.h>
+
+#include <asm/openprom.h>
+#include <asm/oplib.h>
+#include <asm/prom.h>
+#include <asm/uaccess.h>
+
+static DEFINE_MUTEX(op_mutex);
+
+#define OPENPROM_ROOT_INO	0
+
+enum op_inode_type {
+	op_inode_node,
+	op_inode_prop,
+};
+
+union op_inode_data {
+	struct device_node	*node;
+	struct property		*prop;
+};
+
+struct op_inode_info {
+	struct inode		vfs_inode;
+	enum op_inode_type	type;
+	union op_inode_data	u;
+};
+
+static struct inode *openprom_iget(struct super_block *sb, ino_t ino);
+
+static inline struct op_inode_info *OP_I(struct inode *inode)
+{
+	return container_of(inode, struct op_inode_info, vfs_inode);
+}
+
+static int is_string(unsigned char *p, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++) {
+		unsigned char val = p[i];
+
+		if ((i && !val) ||
+		    (val >= ' ' && val <= '~'))
+			continue;
+
+		return 0;
+	}
+
+	return 1;
+}
+
+static int property_show(struct seq_file *f, void *v)
+{
+	struct property *prop = f->private;
+	void *pval;
+	int len;
+
+	len = prop->length;
+	pval = prop->value;
+
+	if (is_string(pval, len)) {
+		while (len > 0) {
+			int n = strlen(pval);
+
+			seq_printf(f, "%s", (char *) pval);
+
+			/* Skip over the NULL byte too.  */
+			pval += n + 1;
+			len -= n + 1;
+
+			if (len > 0)
+				seq_printf(f, " + ");
+		}
+	} else {
+		if (len & 3) {
+			while (len) {
+				len--;
+				if (len)
+					seq_printf(f, "%02x.",
+						   *(unsigned char *) pval);
+				else
+					seq_printf(f, "%02x",
+						   *(unsigned char *) pval);
+				pval++;
+			}
+		} else {
+			while (len >= 4) {
+				len -= 4;
+
+				if (len)
+					seq_printf(f, "%08x.",
+						   *(unsigned int *) pval);
+				else
+					seq_printf(f, "%08x",
+						   *(unsigned int *) pval);
+				pval += 4;
+			}
+		}
+	}
+	seq_printf(f, "\n");
+
+	return 0;
+}
+
+static void *property_start(struct seq_file *f, loff_t *pos)
+{
+	if (*pos == 0)
+		return pos;
+	return NULL;
+}
+
+static void *property_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return NULL;
+}
+
+static void property_stop(struct seq_file *f, void *v)
+{
+	/* Nothing to do */
+}
+
+static const struct seq_operations property_op = {
+	.start		= property_start,
+	.next		= property_next,
+	.stop		= property_stop,
+	.show		= property_show
+};
+
+static int property_open(struct inode *inode, struct file *file)
+{
+	struct op_inode_info *oi = OP_I(inode);
+	int ret;
+
+	BUG_ON(oi->type != op_inode_prop);
+
+	ret = seq_open(file, &property_op);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+		m->private = oi->u.prop;
+	}
+	return ret;
+}
+
+static const struct file_operations openpromfs_prop_ops = {
+	.open		= property_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static int openpromfs_readdir(struct file *, struct dir_context *);
+
+static const struct file_operations openprom_operations = {
+	.read		= generic_read_dir,
+	.iterate	= openpromfs_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, unsigned int);
+
+static const struct inode_operations openprom_inode_operations = {
+	.lookup		= openpromfs_lookup,
+};
+
+static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	struct op_inode_info *ent_oi, *oi = OP_I(dir);
+	struct device_node *dp, *child;
+	struct property *prop;
+	enum op_inode_type ent_type;
+	union op_inode_data ent_data;
+	const char *name;
+	struct inode *inode;
+	unsigned int ino;
+	int len;
+	
+	BUG_ON(oi->type != op_inode_node);
+
+	dp = oi->u.node;
+
+	name = dentry->d_name.name;
+	len = dentry->d_name.len;
+
+	mutex_lock(&op_mutex);
+
+	child = dp->child;
+	while (child) {
+		int n = strlen(child->path_component_name);
+
+		if (len == n &&
+		    !strncmp(child->path_component_name, name, len)) {
+			ent_type = op_inode_node;
+			ent_data.node = child;
+			ino = child->unique_id;
+			goto found;
+		}
+		child = child->sibling;
+	}
+
+	prop = dp->properties;
+	while (prop) {
+		int n = strlen(prop->name);
+
+		if (len == n && !strncmp(prop->name, name, len)) {
+			ent_type = op_inode_prop;
+			ent_data.prop = prop;
+			ino = prop->unique_id;
+			goto found;
+		}
+
+		prop = prop->next;
+	}
+
+	mutex_unlock(&op_mutex);
+	return ERR_PTR(-ENOENT);
+
+found:
+	inode = openprom_iget(dir->i_sb, ino);
+	mutex_unlock(&op_mutex);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	ent_oi = OP_I(inode);
+	ent_oi->type = ent_type;
+	ent_oi->u = ent_data;
+
+	switch (ent_type) {
+	case op_inode_node:
+		inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
+		inode->i_op = &openprom_inode_operations;
+		inode->i_fop = &openprom_operations;
+		set_nlink(inode, 2);
+		break;
+	case op_inode_prop:
+		if (!strcmp(dp->name, "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;
+		inode->i_fop = &openpromfs_prop_ops;
+		set_nlink(inode, 1);
+		inode->i_size = ent_oi->u.prop->length;
+		break;
+	}
+
+	d_add(dentry, inode);
+	return NULL;
+}
+
+static int openpromfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct op_inode_info *oi = OP_I(inode);
+	struct device_node *dp = oi->u.node;
+	struct device_node *child;
+	struct property *prop;
+	int i;
+
+	mutex_lock(&op_mutex);
+	
+	if (ctx->pos == 0) {
+		if (!dir_emit(ctx, ".", 1, inode->i_ino, DT_DIR))
+			goto out;
+		ctx->pos = 1;
+	}
+	if (ctx->pos == 1) {
+		if (!dir_emit(ctx, "..", 2,
+			    (dp->parent == NULL ?
+			     OPENPROM_ROOT_INO :
+			     dp->parent->unique_id), DT_DIR))
+			goto out;
+		ctx->pos = 2;
+	}
+	i = ctx->pos - 2;
+
+	/* First, the children nodes as directories.  */
+	child = dp->child;
+	while (i && child) {
+		child = child->sibling;
+		i--;
+	}
+	while (child) {
+		if (!dir_emit(ctx,
+			    child->path_component_name,
+			    strlen(child->path_component_name),
+			    child->unique_id, DT_DIR))
+			goto out;
+
+		ctx->pos++;
+		child = child->sibling;
+	}
+
+	/* Next, the properties as files.  */
+	prop = dp->properties;
+	while (i && prop) {
+		prop = prop->next;
+		i--;
+	}
+	while (prop) {
+		if (!dir_emit(ctx, prop->name, strlen(prop->name),
+			    prop->unique_id, DT_REG))
+			goto out;
+
+		ctx->pos++;
+		prop = prop->next;
+	}
+
+out:
+	mutex_unlock(&op_mutex);
+	return 0;
+}
+
+static struct kmem_cache *op_inode_cachep;
+
+static struct inode *openprom_alloc_inode(struct super_block *sb)
+{
+	struct op_inode_info *oi;
+
+	oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
+	if (!oi)
+		return NULL;
+
+	return &oi->vfs_inode;
+}
+
+static void openprom_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(op_inode_cachep, OP_I(inode));
+}
+
+static void openprom_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, openprom_i_callback);
+}
+
+static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
+{
+	struct inode *inode;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (inode->i_state & I_NEW) {
+		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;
+		}
+		unlock_new_inode(inode);
+	}
+	return inode;
+}
+
+static int openprom_remount(struct super_block *sb, int *flags, char *data)
+{
+	sync_filesystem(sb);
+	*flags |= MS_NOATIME;
+	return 0;
+}
+
+static const struct super_operations openprom_sops = {
+	.alloc_inode	= openprom_alloc_inode,
+	.destroy_inode	= openprom_destroy_inode,
+	.statfs		= simple_statfs,
+	.remount_fs	= openprom_remount,
+};
+
+static int openprom_fill_super(struct super_block *s, void *data, int silent)
+{
+	struct inode *root_inode;
+	struct op_inode_info *oi;
+	int ret;
+
+	s->s_flags |= MS_NOATIME;
+	s->s_blocksize = 1024;
+	s->s_blocksize_bits = 10;
+	s->s_magic = OPENPROM_SUPER_MAGIC;
+	s->s_op = &openprom_sops;
+	s->s_time_gran = 1;
+	root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
+	if (IS_ERR(root_inode)) {
+		ret = PTR_ERR(root_inode);
+		goto out_no_root;
+	}
+
+	oi = OP_I(root_inode);
+	oi->type = op_inode_node;
+	oi->u.node = of_find_node_by_path("/");
+
+	s->s_root = d_make_root(root_inode);
+	if (!s->s_root)
+		goto out_no_root_dentry;
+	return 0;
+
+out_no_root_dentry:
+	ret = -ENOMEM;
+out_no_root:
+	printk("openprom_fill_super: get root inode failed\n");
+	return ret;
+}
+
+static struct dentry *openprom_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_single(fs_type, flags, data, openprom_fill_super);
+}
+
+static struct file_system_type openprom_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "openpromfs",
+	.mount		= openprom_mount,
+	.kill_sb	= kill_anon_super,
+};
+MODULE_ALIAS_FS("openpromfs");
+
+static void op_inode_init_once(void *data)
+{
+	struct op_inode_info *oi = (struct op_inode_info *) data;
+
+	inode_init_once(&oi->vfs_inode);
+}
+
+static int __init init_openprom_fs(void)
+{
+	int err;
+
+	op_inode_cachep = kmem_cache_create("op_inode_cache",
+					    sizeof(struct op_inode_info),
+					    0,
+					    (SLAB_RECLAIM_ACCOUNT |
+					     SLAB_MEM_SPREAD),
+					    op_inode_init_once);
+	if (!op_inode_cachep)
+		return -ENOMEM;
+
+	err = register_filesystem(&openprom_fs_type);
+	if (err)
+		kmem_cache_destroy(op_inode_cachep);
+
+	return err;
+}
+
+static void __exit exit_openprom_fs(void)
+{
+	unregister_filesystem(&openprom_fs_type);
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(op_inode_cachep);
+}
+
+module_init(init_openprom_fs)
+module_exit(exit_openprom_fs)
+MODULE_LICENSE("GPL");