[TOMOYO #7 28/30] Filesystem part of tamper-proof device filesystem.

[Tetsuo Handa]

This file is almost identical to fs/ramfs/inode.c except that
there are hooks for checking filename-attribute pairs.

Signed-off-by: Kentaro Takeda <takedakn@xxxxxxxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Toshiharu Harada <haradats@xxxxxxxxxxxxx>
---
 fs/syaoran_2.6.c |  342 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 342 insertions(+)

--- /dev/null
+++ linux-2.6.25-rc8-mm1/fs/syaoran_2.6.c
@@ -0,0 +1,342 @@
+/*
+ * fs/syaoran_2.6.c
+ *
+ * Implementation of the Tamper-Proof Device Filesystem.
+ *
+ * Portions Copyright (C) 2005-2008  NTT DATA CORPORATION
+ *
+ * Version: 1.6.0   2008/04/01
+ *
+ * This filesystem is developed using the ramfs implementation.
+ *
+ */
+/*
+ * Resizable simple ram filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ *               2000 Transmeta Corp.
+ *
+ * Usage limits added by David Gibson, Linuxcare Australia.
+ * This file is released under the GPL.
+ */
+
+/*
+ * NOTE! This filesystem is probably most useful
+ * not as a real filesystem, but as an example of
+ * how virtual filesystems can be written.
+ *
+ * It doesn't get much simpler than this. Consider
+ * that this file implements the full semantics of
+ * a POSIX-compliant read-write filesystem.
+ *
+ * Note in particular how the filesystem does not
+ * need to implement any data structures of its own
+ * to keep track of the virtual data: using the VFS
+ * caches is sufficient.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+
+#include <linux/uaccess.h>
+
+#include <linux/namei.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+
+static struct super_operations syaoran_ops;
+static struct address_space_operations syaoran_aops;
+static struct inode_operations syaoran_file_inode_operations;
+static struct inode_operations syaoran_dir_inode_operations;
+static struct inode_operations syaoran_symlink_inode_operations;
+static struct file_operations syaoran_file_operations;
+
+static struct backing_dev_info syaoran_backing_dev_info = {
+	.ra_pages      = 0,    /* No readahead */
+	.capabilities  = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK |
+	BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY |
+	BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP |
+	BDI_CAP_EXEC_MAP,
+};
+
+#include <linux/syaoran.h>
+
+static struct inode *syaoran_get_inode(struct super_block *sb, int mode,
+				       dev_t dev)
+{
+	struct inode *inode = new_inode(sb);
+
+	if (inode) {
+		inode->i_mode = mode;
+		inode->i_uid = current->fsuid;
+		inode->i_gid = current->fsgid;
+		inode->i_blocks = 0;
+		inode->i_mapping->a_ops = &syaoran_aops;
+		inode->i_mapping->backing_dev_info = &syaoran_backing_dev_info;
+		inode->i_ctime = CURRENT_TIME;
+		inode->i_mtime = inode->i_ctime;
+		inode->i_atime = inode->i_mtime;
+		switch (mode & S_IFMT) {
+		default:
+			init_special_inode(inode, mode, dev);
+			if (S_ISBLK(mode))
+				inode->i_fop = &wrapped_def_blk_fops;
+			else if (S_ISCHR(mode))
+				inode->i_fop = &wrapped_def_chr_fops;
+			inode->i_op = &syaoran_file_inode_operations;
+			break;
+		case S_IFREG:
+			inode->i_op = &syaoran_file_inode_operations;
+			inode->i_fop = &syaoran_file_operations;
+			break;
+		case S_IFDIR:
+			inode->i_op = &syaoran_dir_inode_operations;
+			inode->i_fop = &simple_dir_operations;
+			/*
+			 * directory inodes start off with i_nlink == 2
+			 * (for "." entry)
+			 */
+			inode->i_nlink++;
+			break;
+		case S_IFLNK:
+			inode->i_op = &syaoran_symlink_inode_operations;
+			break;
+		}
+	}
+	return inode;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+/* SMP-safe */
+static int syaoran_mknod(struct inode *dir, struct dentry *dentry, int mode,
+			 dev_t dev)
+{
+	struct inode *inode;
+	int error = -ENOSPC;
+	if (syaoran_may_create_node(dentry, mode, dev) < 0)
+		return -EPERM;
+	inode = syaoran_get_inode(dir->i_sb, mode, dev);
+	if (inode) {
+		if (dir->i_mode & S_ISGID) {
+			inode->i_gid = dir->i_gid;
+			if (S_ISDIR(mode))
+				inode->i_mode |= S_ISGID;
+		}
+		d_instantiate(dentry, inode);
+		dget(dentry); /* Extra count - pin the dentry in core */
+		error = 0;
+	}
+	return error;
+}
+
+static int syaoran_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	int retval = syaoran_mknod(dir, dentry, mode | S_IFDIR, 0);
+	if (!retval)
+		dir->i_nlink++;
+	return retval;
+}
+
+static int syaoran_create(struct inode *dir, struct dentry *dentry, int mode,
+			  struct nameidata *nd)
+{
+	return syaoran_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+static int syaoran_symlink(struct inode *dir, struct dentry *dentry,
+			   const char *symname)
+{
+	struct inode *inode;
+	int error = -ENOSPC;
+	if (syaoran_may_create_node(dentry, S_IFLNK, 0) < 0)
+		return -EPERM;
+	inode = syaoran_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
+	if (inode) {
+		int l = strlen(symname)+1;
+		error = page_symlink(inode, symname, l);
+		if (!error) {
+			if (dir->i_mode & S_ISGID)
+				inode->i_gid = dir->i_gid;
+			d_instantiate(dentry, inode);
+			dget(dentry);
+		} else
+			iput(inode);
+	}
+	return error;
+}
+
+static int syaoran_link(struct dentry *old_dentry, struct inode *dir,
+			struct dentry *dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	if (!inode || syaoran_may_create_node(dentry, inode->i_mode,
+					      inode->i_rdev) < 0)
+		return -EPERM;
+	return simple_link(old_dentry, dir, dentry);
+}
+
+static int syaoran_unlink(struct inode *dir, struct dentry *dentry)
+{
+	if (syaoran_may_modify_node(dentry, MAY_DELETE) < 0)
+		return -EPERM;
+	return simple_unlink(dir, dentry);
+}
+
+static int syaoran_rename(struct inode *old_dir, struct dentry *old_dentry,
+			  struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	if (!inode || syaoran_may_modify_node(old_dentry, MAY_DELETE) < 0 ||
+	    syaoran_may_create_node(new_dentry, inode->i_mode,
+				    inode->i_rdev) < 0)
+		return -EPERM;
+	return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
+}
+
+static int syaoran_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	if (syaoran_may_modify_node(dentry, MAY_DELETE) < 0)
+		return -EPERM;
+	return simple_rmdir(dir, dentry);
+}
+
+static int syaoran_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = dentry->d_inode;
+	int error = inode_change_ok(inode, attr);
+	if (!error) {
+		unsigned int ia_valid = attr->ia_valid;
+		unsigned int flags = 0;
+		if (ia_valid & (ATTR_UID | ATTR_GID))
+			flags |= MAY_CHOWN;
+		if (ia_valid & ATTR_MODE)
+			flags |= MAY_CHMOD;
+		if (syaoran_may_modify_node(dentry, flags) < 0)
+			return -EPERM;
+		if (!error)
+			error = inode_setattr(inode, attr);
+	}
+	return error;
+}
+
+static int syaoran_set_page_dirty_no_writeback(struct page *page)
+{
+	if (!PageDirty(page))
+		SetPageDirty(page);
+	return 0;
+}
+static struct address_space_operations syaoran_aops = {
+	.readpage       = simple_readpage,
+	.write_begin    = simple_write_begin,
+	.write_end      = simple_write_end,
+	.set_page_dirty = syaoran_set_page_dirty_no_writeback,
+};
+
+static struct file_operations syaoran_file_operations = {
+	.aio_read    = generic_file_aio_read,
+	.read        = do_sync_read,
+	.aio_write   = generic_file_aio_write,
+	.write       = do_sync_write,
+	.mmap        = generic_file_mmap,
+	.fsync       = simple_sync_file,
+	.splice_read = generic_file_splice_read,
+	.llseek      = generic_file_llseek,
+};
+
+static struct inode_operations syaoran_file_inode_operations = {
+	.getattr    = simple_getattr,
+	.setattr    = syaoran_setattr,
+};
+
+static struct inode_operations syaoran_dir_inode_operations = {
+	.create     = syaoran_create,
+	.lookup     = simple_lookup,
+	.link       = syaoran_link,
+	.unlink     = syaoran_unlink,
+	.symlink    = syaoran_symlink,
+	.mkdir      = syaoran_mkdir,
+	.rmdir      = syaoran_rmdir,
+	.mknod      = syaoran_mknod,
+	.rename     = syaoran_rename,
+	.setattr    = syaoran_setattr,
+};
+
+static struct inode_operations syaoran_symlink_inode_operations = {
+	.readlink       = generic_readlink,
+	.follow_link    = page_follow_link_light,
+	.put_link       = page_put_link,
+	.setattr        = syaoran_setattr,
+};
+
+static struct super_operations syaoran_ops = {
+	.statfs     = simple_statfs,
+	.drop_inode = generic_delete_inode,
+	.put_super  = syaoran_put_super,
+};
+
+static int syaoran_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct inode *inode;
+	struct dentry *root;
+
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_blocksize = PAGE_CACHE_SIZE;
+	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+	sb->s_magic = SYAORAN_MAGIC;
+	sb->s_op = &syaoran_ops;
+	sb->s_time_gran = 1;
+	{
+		int error = syaoran_initialize(sb, data);
+		if (error < 0)
+			return error;
+	}
+	inode = syaoran_get_inode(sb, S_IFDIR | 0755, 0);
+	if (!inode)
+		return -ENOMEM;
+
+	root = d_alloc_root(inode);
+	if (!root) {
+		iput(inode);
+		return -ENOMEM;
+	}
+	sb->s_root = root;
+	syaoran_make_initial_nodes(sb);
+	return 0;
+}
+
+static int syaoran_get_sb(struct file_system_type *fs_type,
+			  int flags, const char *dev_name, void *data,
+			  struct vfsmount *mnt)
+{
+	return get_sb_nodev(fs_type, flags, data, syaoran_fill_super, mnt);
+}
+
+static struct file_system_type syaoran_fs_type = {
+	.owner      = THIS_MODULE,
+	.name       = "syaoran",
+	.get_sb     = syaoran_get_sb,
+	.kill_sb    = kill_litter_super,
+};
+
+static int __init init_syaoran_fs(void)
+{
+	return register_filesystem(&syaoran_fs_type);
+}
+
+static void __exit exit_syaoran_fs(void)
+{
+	unregister_filesystem(&syaoran_fs_type);
+}
+
+module_init(init_syaoran_fs);
+module_exit(exit_syaoran_fs);
+
+MODULE_LICENSE("GPL");

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