xattr.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) International Business Machines  Corp., 2000-2004
 *   Copyright (C) Christoph Hellwig, 2002
 */

#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/slab.h>
#include <linux/quotaops.h>
#include <linux/security.h>
#include "jfs_incore.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_debug.h"
#include "jfs_dinode.h"
#include "jfs_extent.h"
#include "jfs_metapage.h"
#include "jfs_xattr.h"
#include "jfs_acl.h"

/*
 *	jfs_xattr.c: extended attribute service
 *
 * Overall design --
 *
 * Format:
 *
 *   Extended attribute lists (jfs_ea_list) consist of an overall size (32 bit
 *   value) and a variable (0 or more) number of extended attribute
 *   entries.  Each extended attribute entry (jfs_ea) is a <name,value> double
 *   where <name> is constructed from a null-terminated ascii string
 *   (1 ... 255 bytes in the name) and <value> is arbitrary 8 bit data
 *   (1 ... 65535 bytes).  The in-memory format is
 *
 *   0       1        2        4                4 + namelen + 1
 *   +-------+--------+--------+----------------+-------------------+
 *   | Flags | Name   | Value  | Name String \0 | Data . . . .      |
 *   |       | Length | Length |                |                   |
 *   +-------+--------+--------+----------------+-------------------+
 *
 *   A jfs_ea_list then is structured as
 *
 *   0            4                   4 + EA_SIZE(ea1)
 *   +------------+-------------------+--------------------+-----
 *   | Overall EA | First FEA Element | Second FEA Element | .....
 *   | List Size  |                   |                    |
 *   +------------+-------------------+--------------------+-----
 *
 *   On-disk:
 *
 *	FEALISTs are stored on disk using blocks allocated by dbAlloc() and
 *	written directly. An EA list may be in-lined in the inode if there is
 *	sufficient room available.
 */

struct ea_buffer { … };

/*
 * ea_buffer.flag values
 */
#define EA_INLINE …
#define EA_EXTENT …
#define EA_NEW …
#define EA_MALLOC …


/*
 * Mapping of on-disk attribute names: for on-disk attribute names with an
 * unknown prefix (not "system.", "user.", "security.", or "trusted."), the
 * prefix "os2." is prepended.  On the way back to disk, "os2." prefixes are
 * stripped and we make sure that the remaining name does not start with one
 * of the know prefixes.
 */

static int is_known_namespace(const char *name)
{ … }

static inline int name_size(struct jfs_ea *ea)
{ … }

static inline int copy_name(char *buffer, struct jfs_ea *ea)
{ … }

/* Forward references */
static void ea_release(struct inode *inode, struct ea_buffer *ea_buf);

/*
 * NAME: ea_write_inline
 *
 * FUNCTION: Attempt to write an EA inline if area is available
 *
 * PRE CONDITIONS:
 *	Already verified that the specified EA is small enough to fit inline
 *
 * PARAMETERS:
 *	ip	- Inode pointer
 *	ealist	- EA list pointer
 *	size	- size of ealist in bytes
 *	ea	- dxd_t structure to be filled in with necessary EA information
 *		  if we successfully copy the EA inline
 *
 * NOTES:
 *	Checks if the inode's inline area is available.  If so, copies EA inline
 *	and sets <ea> fields appropriately.  Otherwise, returns failure, EA will
 *	have to be put into an extent.
 *
 * RETURNS: 0 for successful copy to inline area; -1 if area not available
 */
static int ea_write_inline(struct inode *ip, struct jfs_ea_list *ealist,
			   int size, dxd_t * ea)
{ … }

/*
 * NAME: ea_write
 *
 * FUNCTION: Write an EA for an inode
 *
 * PRE CONDITIONS: EA has been verified
 *
 * PARAMETERS:
 *	ip	- Inode pointer
 *	ealist	- EA list pointer
 *	size	- size of ealist in bytes
 *	ea	- dxd_t structure to be filled in appropriately with where the
 *		  EA was copied
 *
 * NOTES: Will write EA inline if able to, otherwise allocates blocks for an
 *	extent and synchronously writes it to those blocks.
 *
 * RETURNS: 0 for success; Anything else indicates failure
 */
static int ea_write(struct inode *ip, struct jfs_ea_list *ealist, int size,
		       dxd_t * ea)
{ … }

/*
 * NAME: ea_read_inline
 *
 * FUNCTION: Read an inlined EA into user's buffer
 *
 * PARAMETERS:
 *	ip	- Inode pointer
 *	ealist	- Pointer to buffer to fill in with EA
 *
 * RETURNS: 0
 */
static int ea_read_inline(struct inode *ip, struct jfs_ea_list *ealist)
{ … }

/*
 * NAME: ea_read
 *
 * FUNCTION: copy EA data into user's buffer
 *
 * PARAMETERS:
 *	ip	- Inode pointer
 *	ealist	- Pointer to buffer to fill in with EA
 *
 * NOTES:  If EA is inline calls ea_read_inline() to copy EA.
 *
 * RETURNS: 0 for success; other indicates failure
 */
static int ea_read(struct inode *ip, struct jfs_ea_list *ealist)
{ … }

/*
 * NAME: ea_get
 *
 * FUNCTION: Returns buffer containing existing extended attributes.
 *	     The size of the buffer will be the larger of the existing
 *	     attributes size, or min_size.
 *
 *	     The buffer, which may be inlined in the inode or in the
 *	     page cache must be release by calling ea_release or ea_put
 *
 * PARAMETERS:
 *	inode	- Inode pointer
 *	ea_buf	- Structure to be populated with ealist and its metadata
 *	min_size- minimum size of buffer to be returned
 *
 * RETURNS: 0 for success; Other indicates failure
 */
static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
{ … }

static void ea_release(struct inode *inode, struct ea_buffer *ea_buf)
{ … }

static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
		  int new_size)
{ … }

int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
		   const void *value, size_t value_len, int flags)
{ … }

ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
		       size_t buf_size)
{ … }

/*
 * No special permissions are needed to list attributes except for trusted.*
 */
static inline int can_list(struct jfs_ea *ea)
{ … }

ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
{ … }

static int __jfs_xattr_set(struct inode *inode, const char *name,
			   const void *value, size_t size, int flags)
{ … }

static int jfs_xattr_get(const struct xattr_handler *handler,
			 struct dentry *unused, struct inode *inode,
			 const char *name, void *value, size_t size)
{ … }

static int jfs_xattr_set(const struct xattr_handler *handler,
			 struct mnt_idmap *idmap,
			 struct dentry *unused, struct inode *inode,
			 const char *name, const void *value,
			 size_t size, int flags)
{ … }

static int jfs_xattr_get_os2(const struct xattr_handler *handler,
			     struct dentry *unused, struct inode *inode,
			     const char *name, void *value, size_t size)
{ … }

static int jfs_xattr_set_os2(const struct xattr_handler *handler,
			     struct mnt_idmap *idmap,
			     struct dentry *unused, struct inode *inode,
			     const char *name, const void *value,
			     size_t size, int flags)
{ … }

static const struct xattr_handler jfs_user_xattr_handler = …;

static const struct xattr_handler jfs_os2_xattr_handler = …;

static const struct xattr_handler jfs_security_xattr_handler = …;

static const struct xattr_handler jfs_trusted_xattr_handler = …;

const struct xattr_handler * const jfs_xattr_handlers[] = …;


#ifdef CONFIG_JFS_SECURITY
static int jfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
			  void *fs_info)
{ … }

int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir,
		      const struct qstr *qstr)
{ … }
#endif
linux/fs/jfs/xattr.c
