fs/xfs/xfs_acl.c - kernel/bruno - Git at Google

 /*
  * Copyright (c) 2008, Christoph Hellwig
  * All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it would be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write the Free Software Foundation,
  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 #include "xfs.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
 #include "xfs_acl.h"
 #include "xfs_attr.h"
 #include "xfs_trace.h"
 #include <linux/slab.h>
 #include <linux/xattr.h>
 #include <linux/posix_acl_xattr.h>


 /*
  * Locking scheme:
  *  - all ACL updates are protected by inode->i_mutex, which is taken before
  *    calling into this file.
  */

 STATIC struct posix_acl *
 xfs_acl_from_disk(
 	const struct xfs_acl	*aclp,
 	int			len,
 	int			max_entries)
 {
 	struct posix_acl_entry *acl_e;
 	struct posix_acl *acl;
 	const struct xfs_acl_entry *ace;
 	unsigned int count, i;

 	if (len < sizeof(*aclp))
 		return ERR_PTR(-EFSCORRUPTED);
 	count = be32_to_cpu(aclp->acl_cnt);
 	if (count > max_entries || XFS_ACL_SIZE(count) != len)
 		return ERR_PTR(-EFSCORRUPTED);

 	acl = posix_acl_alloc(count, GFP_KERNEL);
 	if (!acl)
 		return ERR_PTR(-ENOMEM);

 	for (i = 0; i < count; i++) {
 		acl_e = &acl->a_entries[i];
 		ace = &aclp->acl_entry[i];

 		/*
 		 * The tag is 32 bits on disk and 16 bits in core.
 		 *
 		 * Because every access to it goes through the core
 		 * format first this is not a problem.
 		 */
 		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
 		acl_e->e_perm = be16_to_cpu(ace->ae_perm);

 		switch (acl_e->e_tag) {
 		case ACL_USER:
 			acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
 			break;
 		case ACL_GROUP:
 			acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
 			break;
 		case ACL_USER_OBJ:
 		case ACL_GROUP_OBJ:
 		case ACL_MASK:
 		case ACL_OTHER:
 			break;
 		default:
 			goto fail;
 		}
 	}
 	return acl;

 fail:
 	posix_acl_release(acl);
 	return ERR_PTR(-EINVAL);
 }

 STATIC void
 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
 {
 	const struct posix_acl_entry *acl_e;
 	struct xfs_acl_entry *ace;
 	int i;

 	aclp->acl_cnt = cpu_to_be32(acl->a_count);
 	for (i = 0; i < acl->a_count; i++) {
 		ace = &aclp->acl_entry[i];
 		acl_e = &acl->a_entries[i];

 		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
 		switch (acl_e->e_tag) {
 		case ACL_USER:
 			ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
 			break;
 		case ACL_GROUP:
 			ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
 			break;
 		default:
 			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
 			break;
 		}

 		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
 	}
 }

 struct posix_acl *
 xfs_get_acl(struct inode *inode, int type)
 {
 	struct xfs_inode *ip = XFS_I(inode);
 	struct posix_acl *acl = NULL;
 	struct xfs_acl *xfs_acl;
 	unsigned char *ea_name;
 	int error;
 	int len;

 	trace_xfs_get_acl(ip);

 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		ea_name = SGI_ACL_FILE;
 		break;
 	case ACL_TYPE_DEFAULT:
 		ea_name = SGI_ACL_DEFAULT;
 		break;
 	default:
 		BUG();
 	}

 	/*
 	 * If we have a cached ACLs value just return it, not need to
 	 * go out to the disk.
 	 */
 	len = XFS_ACL_MAX_SIZE(ip->i_mount);
 	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
 	if (!xfs_acl)
 		return ERR_PTR(-ENOMEM);

 	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
 							&len, ATTR_ROOT);
 	if (error) {
 		/*
 		 * If the attribute doesn't exist make sure we have a negative
 		 * cache entry, for any other error assume it is transient and
 		 * leave the cache entry as ACL_NOT_CACHED.
 		 */
 		if (error == -ENOATTR)
 			goto out_update_cache;
 		acl = ERR_PTR(error);
 		goto out;
 	}

 	acl = xfs_acl_from_disk(xfs_acl, len, XFS_ACL_MAX_ENTRIES(ip->i_mount));
 	if (IS_ERR(acl))
 		goto out;

 out_update_cache:
 	set_cached_acl(inode, type, acl);
 out:
 	kmem_free(xfs_acl);
 	return acl;
 }

 STATIC int
 __xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
 {
 	struct xfs_inode *ip = XFS_I(inode);
 	unsigned char *ea_name;
 	int error;

 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		ea_name = SGI_ACL_FILE;
 		break;
 	case ACL_TYPE_DEFAULT:
 		if (!S_ISDIR(inode->i_mode))
 			return acl ? -EACCES : 0;
 		ea_name = SGI_ACL_DEFAULT;
 		break;
 	default:
 		return -EINVAL;
 	}

 	if (acl) {
 		struct xfs_acl *xfs_acl;
 		int len = XFS_ACL_MAX_SIZE(ip->i_mount);

 		xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
 		if (!xfs_acl)
 			return -ENOMEM;

 		xfs_acl_to_disk(xfs_acl, acl);

 		/* subtract away the unused acl entries */
 		len -= sizeof(struct xfs_acl_entry) *
 			 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);

 		error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
 				len, ATTR_ROOT);

 		kmem_free(xfs_acl);
 	} else {
 		/*
 		 * A NULL ACL argument means we want to remove the ACL.
 		 */
 		error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);

 		/*
 		 * If the attribute didn't exist to start with that's fine.
 		 */
 		if (error == -ENOATTR)
 			error = 0;
 	}

 	if (!error)
 		set_cached_acl(inode, type, acl);
 	return error;
 }

 static int
 xfs_set_mode(struct inode *inode, umode_t mode)
 {
 	int error = 0;

 	if (mode != inode->i_mode) {
 		struct iattr iattr;

 		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
 		iattr.ia_mode = mode;
 		iattr.ia_ctime = current_fs_time(inode->i_sb);

 		error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
 	}

 	return error;
 }

 static int
 xfs_acl_exists(struct inode *inode, unsigned char *name)
 {
 	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));

 	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
 			    ATTR_ROOT|ATTR_KERNOVAL) == 0);
 }

 int
 posix_acl_access_exists(struct inode *inode)
 {
 	return xfs_acl_exists(inode, SGI_ACL_FILE);
 }

 int
 posix_acl_default_exists(struct inode *inode)
 {
 	if (!S_ISDIR(inode->i_mode))
 		return 0;
 	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
 }

 int
 xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
 	int error = 0;

 	if (!acl)
 		goto set_acl;

 	error = -E2BIG;
 	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
 		return error;

 	if (type == ACL_TYPE_ACCESS) {
 		umode_t mode;

 		error = posix_acl_update_mode(inode, &mode, &acl);
 		if (error)
 			return error;
 		error = xfs_set_mode(inode, mode);
 		if (error)
 			return error;
 	}

  set_acl:
 	return __xfs_set_acl(inode, type, acl);
 }
	/*
	* Copyright (c) 2008, Christoph Hellwig
	* All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it would be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*/
	#include "xfs.h"
	#include "xfs_format.h"
	#include "xfs_log_format.h"
	#include "xfs_trans_resv.h"
	#include "xfs_mount.h"
	#include "xfs_inode.h"
	#include "xfs_acl.h"
	#include "xfs_attr.h"
	#include "xfs_trace.h"
	#include <linux/slab.h>
	#include <linux/xattr.h>
	#include <linux/posix_acl_xattr.h>


	/*
	* Locking scheme:
	* - all ACL updates are protected by inode->i_mutex, which is taken before
	* calling into this file.
	*/

	STATIC struct posix_acl *
	xfs_acl_from_disk(
	const struct xfs_acl *aclp,
	int len,
	int max_entries)
	{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	const struct xfs_acl_entry *ace;
	unsigned int count, i;

	if (len < sizeof(*aclp))
	return ERR_PTR(-EFSCORRUPTED);
	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries \|\| XFS_ACL_SIZE(count) != len)
	return ERR_PTR(-EFSCORRUPTED);

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
	return ERR_PTR(-ENOMEM);

	for (i = 0; i < count; i++) {
	acl_e = &acl->a_entries[i];
	ace = &aclp->acl_entry[i];

	/*
	* The tag is 32 bits on disk and 16 bits in core.
	*
	* Because every access to it goes through the core
	* format first this is not a problem.
	*/
	acl_e->e_tag = be32_to_cpu(ace->ae_tag);
	acl_e->e_perm = be16_to_cpu(ace->ae_perm);

	switch (acl_e->e_tag) {
	case ACL_USER:
	acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
	break;
	case ACL_GROUP:
	acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
	break;
	case ACL_USER_OBJ:
	case ACL_GROUP_OBJ:
	case ACL_MASK:
	case ACL_OTHER:
	break;
	default:
	goto fail;
	}
	}
	return acl;

	fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
	}

	STATIC void
	xfs_acl_to_disk(struct xfs_acl aclp, const struct posix_acl acl)
	{
	const struct posix_acl_entry *acl_e;
	struct xfs_acl_entry *ace;
	int i;

	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	for (i = 0; i < acl->a_count; i++) {
	ace = &aclp->acl_entry[i];
	acl_e = &acl->a_entries[i];

	ace->ae_tag = cpu_to_be32(acl_e->e_tag);
	switch (acl_e->e_tag) {
	case ACL_USER:
	ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
	break;
	case ACL_GROUP:
	ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
	break;
	default:
	ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
	break;
	}

	ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	}
	}

	struct posix_acl *
	xfs_get_acl(struct inode *inode, int type)
	{
	struct xfs_inode *ip = XFS_I(inode);
	struct posix_acl *acl = NULL;
	struct xfs_acl *xfs_acl;
	unsigned char *ea_name;
	int error;
	int len;

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
	ea_name = SGI_ACL_FILE;
	break;
	case ACL_TYPE_DEFAULT:
	ea_name = SGI_ACL_DEFAULT;
	break;
	default:
	BUG();
	}

	/*
	* If we have a cached ACLs value just return it, not need to
	* go out to the disk.
	*/
	len = XFS_ACL_MAX_SIZE(ip->i_mount);
	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	if (!xfs_acl)
	return ERR_PTR(-ENOMEM);

	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
	&len, ATTR_ROOT);
	if (error) {
	/*
	* If the attribute doesn't exist make sure we have a negative
	* cache entry, for any other error assume it is transient and
	* leave the cache entry as ACL_NOT_CACHED.
	*/
	if (error == -ENOATTR)
	goto out_update_cache;
	acl = ERR_PTR(error);
	goto out;
	}

	acl = xfs_acl_from_disk(xfs_acl, len, XFS_ACL_MAX_ENTRIES(ip->i_mount));
	if (IS_ERR(acl))
	goto out;

	out_update_cache:
	set_cached_acl(inode, type, acl);
	out:
	kmem_free(xfs_acl);
	return acl;
	}

	STATIC int
	__xfs_set_acl(struct inode inode, int type, struct posix_acl acl)
	{
	struct xfs_inode *ip = XFS_I(inode);
	unsigned char *ea_name;
	int error;

	switch (type) {
	case ACL_TYPE_ACCESS:
	ea_name = SGI_ACL_FILE;
	break;
	case ACL_TYPE_DEFAULT:
	if (!S_ISDIR(inode->i_mode))
	return acl ? -EACCES : 0;
	ea_name = SGI_ACL_DEFAULT;
	break;
	default:
	return -EINVAL;
	}

	if (acl) {
	struct xfs_acl *xfs_acl;
	int len = XFS_ACL_MAX_SIZE(ip->i_mount);

	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
	if (!xfs_acl)
	return -ENOMEM;

	xfs_acl_to_disk(xfs_acl, acl);

	/* subtract away the unused acl entries */
	len -= sizeof(struct xfs_acl_entry) *
	(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);

	error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
	len, ATTR_ROOT);

	kmem_free(xfs_acl);
	} else {
	/*
	* A NULL ACL argument means we want to remove the ACL.
	*/
	error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);

	/*
	* If the attribute didn't exist to start with that's fine.
	*/
	if (error == -ENOATTR)
	error = 0;
	}

	if (!error)
	set_cached_acl(inode, type, acl);
	return error;
	}

	static int
	xfs_set_mode(struct inode *inode, umode_t mode)
	{
	int error = 0;

	if (mode != inode->i_mode) {
	struct iattr iattr;

	iattr.ia_valid = ATTR_MODE \| ATTR_CTIME;
	iattr.ia_mode = mode;
	iattr.ia_ctime = current_fs_time(inode->i_sb);

	error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
	}

	return error;
	}

	static int
	xfs_acl_exists(struct inode inode, unsigned char name)
	{
	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));

	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
	ATTR_ROOT\|ATTR_KERNOVAL) == 0);
	}

	int
	posix_acl_access_exists(struct inode *inode)
	{
	return xfs_acl_exists(inode, SGI_ACL_FILE);
	}

	int
	posix_acl_default_exists(struct inode *inode)
	{
	if (!S_ISDIR(inode->i_mode))
	return 0;
	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
	}

	int
	xfs_set_acl(struct inode inode, struct posix_acl acl, int type)
	{
	int error = 0;

	if (!acl)
	goto set_acl;

	error = -E2BIG;
	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
	return error;

	if (type == ACL_TYPE_ACCESS) {
	umode_t mode;

	error = posix_acl_update_mode(inode, &mode, &acl);
	if (error)
	return error;
	error = xfs_set_mode(inode, mode);
	if (error)
	return error;
	}

	set_acl:
	return __xfs_set_acl(inode, type, acl);
	}