1. 根目录:
2. fs
3. hfsplus
4. ioctl.c

/*
 *  linux/fs/hfsplus/ioctl.c
 *
 * Copyright (C) 2003
 * Ethan Benson <erbenson@alaska.net>
 * partially derived from linux/fs/ext2/ioctl.c
 * Copyright (C) 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 * hfsplus ioctls
 */

#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/sched.h>
#include <linux/xattr.h>
#include <asm/uaccess.h>
#include "hfsplus_fs.h"

/*
 * "Blessing" an HFS+ filesystem writes metadata to the superblock informing
 * the platform firmware which file to boot from
 */
static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
{
	struct dentry *dentry = file->f_path.dentry;
	struct inode *inode = dentry->d_inode;
	struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
	struct hfsplus_vh *vh = sbi->s_vhdr;
	struct hfsplus_vh *bvh = sbi->s_backup_vhdr;
	u32 cnid = (unsigned long)dentry->d_fsdata;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	mutex_lock(&sbi->vh_mutex);

	/* Directory containing the bootable system */
	vh->finder_info[0] = bvh->finder_info[0] =
		cpu_to_be32(parent_ino(dentry));

	/*
	 * Bootloader. Just using the inode here breaks in the case of
	 * hard links - the firmware wants the ID of the hard link file,
	 * but the inode points at the indirect inode
	 */
	vh->finder_info[1] = bvh->finder_info[1] = cpu_to_be32(cnid);

	/* Per spec, the OS X system folder - same as finder_info[0] here */
	vh->finder_info[5] = bvh->finder_info[5] =
		cpu_to_be32(parent_ino(dentry));

	mutex_unlock(&sbi->vh_mutex);
	return 0;
}

static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
	unsigned int flags = 0;

	if (inode->i_flags & S_IMMUTABLE)
		flags |= FS_IMMUTABLE_FL;
	if (inode->i_flags & S_APPEND)
		flags |= FS_APPEND_FL;
	if (hip->userflags & HFSPLUS_FLG_NODUMP)
		flags |= FS_NODUMP_FL;

	return put_user(flags, user_flags);
}

static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
	unsigned int flags;
	int err = 0;

	err = mnt_want_write_file(file);
	if (err)
		goto out;

	if (!inode_owner_or_capable(inode)) {
		err = -EACCES;
		goto out_drop_write;
	}

	if (get_user(flags, user_flags)) {
		err = -EFAULT;
		goto out_drop_write;
	}

	mutex_lock(&inode->i_mutex);

	if ((flags & (FS_IMMUTABLE_FL|FS_APPEND_FL)) ||
	    inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
		if (!capable(CAP_LINUX_IMMUTABLE)) {
			err = -EPERM;
			goto out_unlock_inode;
		}
	}

	/* don't silently ignore unsupported ext2 flags */
	if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
		err = -EOPNOTSUPP;
		goto out_unlock_inode;
	}

	if (flags & FS_IMMUTABLE_FL)
		inode->i_flags |= S_IMMUTABLE;
	else
		inode->i_flags &= ~S_IMMUTABLE;

	if (flags & FS_APPEND_FL)
		inode->i_flags |= S_APPEND;
	else
		inode->i_flags &= ~S_APPEND;

	if (flags & FS_NODUMP_FL)
		hip->userflags |= HFSPLUS_FLG_NODUMP;
	else
		hip->userflags &= ~HFSPLUS_FLG_NODUMP;

	inode->i_ctime = CURRENT_TIME_SEC;
	mark_inode_dirty(inode);

out_unlock_inode:
	mutex_unlock(&inode->i_mutex);
out_drop_write:
	mnt_drop_write_file(file);
out:
	return err;
}

long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;

	switch (cmd) {
	case HFSPLUS_IOC_EXT2_GETFLAGS:
		return hfsplus_ioctl_getflags(file, argp);
	case HFSPLUS_IOC_EXT2_SETFLAGS:
		return hfsplus_ioctl_setflags(file, argp);
	case HFSPLUS_IOC_BLESS:
		return hfsplus_ioctl_bless(file, argp);
	default:
		return -ENOTTY;
	}
}

int hfsplus_setxattr(struct dentry *dentry, const char *name,
		     const void *value, size_t size, int flags)
{
	struct inode *inode = dentry->d_inode;
	struct hfs_find_data fd;
	hfsplus_cat_entry entry;
	struct hfsplus_cat_file *file;
	int res;

	if (!S_ISREG(inode->i_mode) || HFSPLUS_IS_RSRC(inode))
		return -EOPNOTSUPP;

	res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
	if (res)
		return res;
	res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
	if (res)
		goto out;
	hfs_bnode_read(fd.bnode, &entry, fd.entryoffset,
			sizeof(struct hfsplus_cat_file));
	file = &entry.file;

	if (!strcmp(name, "hfs.type")) {
		if (size == 4)
			memcpy(&file->user_info.fdType, value, 4);
		else
			res = -ERANGE;
	} else if (!strcmp(name, "hfs.creator")) {
		if (size == 4)
			memcpy(&file->user_info.fdCreator, value, 4);
		else
			res = -ERANGE;
	} else
		res = -EOPNOTSUPP;
	if (!res) {
		hfs_bnode_write(fd.bnode, &entry, fd.entryoffset,
				sizeof(struct hfsplus_cat_file));
		hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
	}
out:
	hfs_find_exit(&fd);
	return res;
}

ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name,
			 void *value, size_t size)
{
	struct inode *inode = dentry->d_inode;
	struct hfs_find_data fd;
	hfsplus_cat_entry entry;
	struct hfsplus_cat_file *file;
	ssize_t res = 0;

	if (!S_ISREG(inode->i_mode) || HFSPLUS_IS_RSRC(inode))
		return -EOPNOTSUPP;

	if (size) {
		res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
		if (res)
			return res;
		res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
		if (res)
			goto out;
		hfs_bnode_read(fd.bnode, &entry, fd.entryoffset,
				sizeof(struct hfsplus_cat_file));
	}
	file = &entry.file;

	if (!strcmp(name, "hfs.type")) {
		if (size >= 4) {
			memcpy(value, &file->user_info.fdType, 4);
			res = 4;
		} else
			res = size ? -ERANGE : 4;
	} else if (!strcmp(name, "hfs.creator")) {
		if (size >= 4) {
			memcpy(value, &file->user_info.fdCreator, 4);
			res = 4;
		} else
			res = size ? -ERANGE : 4;
	} else
		res = -EOPNOTSUPP;
out:
	if (size)
		hfs_find_exit(&fd);
	return res;
}

#define HFSPLUS_ATTRLIST_SIZE (sizeof("hfs.creator")+sizeof("hfs.type"))

ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
	struct inode *inode = dentry->d_inode;

	if (!S_ISREG(inode->i_mode) || HFSPLUS_IS_RSRC(inode))
		return -EOPNOTSUPP;

	if (!buffer || !size)
		return HFSPLUS_ATTRLIST_SIZE;
	if (size < HFSPLUS_ATTRLIST_SIZE)
		return -ERANGE;
	strcpy(buffer, "hfs.type");
	strcpy(buffer + sizeof("hfs.type"), "hfs.creator");

	return HFSPLUS_ATTRLIST_SIZE;
}