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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/jfs/xattr.c

1187 строки
29 KiB
C
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/*
* Copyright (C) International Business Machines Corp., 2000-2004
* Copyright (C) Christoph Hellwig, 2002
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will 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 to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.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 {
int flag; /* Indicates what storage xattr points to */
int max_size; /* largest xattr that fits in current buffer */
dxd_t new_ea; /* dxd to replace ea when modifying xattr */
struct metapage *mp; /* metapage containing ea list */
struct jfs_ea_list *xattr; /* buffer containing ea list */
};
/*
* ea_buffer.flag values
*/
#define EA_INLINE 0x0001
#define EA_EXTENT 0x0002
#define EA_NEW 0x0004
#define EA_MALLOC 0x0008
/* Namespaces */
#define XATTR_SYSTEM_PREFIX "system."
#define XATTR_SYSTEM_PREFIX_LEN (sizeof (XATTR_SYSTEM_PREFIX) - 1)
#define XATTR_USER_PREFIX "user."
#define XATTR_USER_PREFIX_LEN (sizeof (XATTR_USER_PREFIX) - 1)
#define XATTR_OS2_PREFIX "os2."
#define XATTR_OS2_PREFIX_LEN (sizeof (XATTR_OS2_PREFIX) - 1)
/* XATTR_SECURITY_PREFIX is defined in include/linux/xattr.h */
#define XATTR_SECURITY_PREFIX_LEN (sizeof (XATTR_SECURITY_PREFIX) - 1)
#define XATTR_TRUSTED_PREFIX "trusted."
#define XATTR_TRUSTED_PREFIX_LEN (sizeof (XATTR_TRUSTED_PREFIX) - 1)
/*
* These three routines are used to recognize on-disk extended attributes
* that are in a recognized namespace. If the attribute is not recognized,
* "os2." is prepended to the name
*/
static inline int is_os2_xattr(struct jfs_ea *ea)
{
/*
* Check for "system."
*/
if ((ea->namelen >= XATTR_SYSTEM_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return FALSE;
/*
* Check for "user."
*/
if ((ea->namelen >= XATTR_USER_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
return FALSE;
/*
* Check for "security."
*/
if ((ea->namelen >= XATTR_SECURITY_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_SECURITY_PREFIX,
XATTR_SECURITY_PREFIX_LEN))
return FALSE;
/*
* Check for "trusted."
*/
if ((ea->namelen >= XATTR_TRUSTED_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
return FALSE;
/*
* Add any other valid namespace prefixes here
*/
/*
* We assume it's OS/2's flat namespace
*/
return TRUE;
}
static inline int name_size(struct jfs_ea *ea)
{
if (is_os2_xattr(ea))
return ea->namelen + XATTR_OS2_PREFIX_LEN;
else
return ea->namelen;
}
static inline int copy_name(char *buffer, struct jfs_ea *ea)
{
int len = ea->namelen;
if (is_os2_xattr(ea)) {
memcpy(buffer, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN);
buffer += XATTR_OS2_PREFIX_LEN;
len += XATTR_OS2_PREFIX_LEN;
}
memcpy(buffer, ea->name, ea->namelen);
buffer[ea->namelen] = 0;
return len;
}
/* 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)
{
struct jfs_inode_info *ji = JFS_IP(ip);
/*
* Make sure we have an EA -- the NULL EA list is valid, but you
* can't copy it!
*/
if (ealist && size > sizeof (struct jfs_ea_list)) {
assert(size <= sizeof (ji->i_inline_ea));
/*
* See if the space is available or if it is already being
* used for an inline EA.
*/
if (!(ji->mode2 & INLINEEA) && !(ji->ea.flag & DXD_INLINE))
return -EPERM;
DXDsize(ea, size);
DXDlength(ea, 0);
DXDaddress(ea, 0);
memcpy(ji->i_inline_ea, ealist, size);
ea->flag = DXD_INLINE;
ji->mode2 &= ~INLINEEA;
} else {
ea->flag = 0;
DXDsize(ea, 0);
DXDlength(ea, 0);
DXDaddress(ea, 0);
/* Free up INLINE area */
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
}
return 0;
}
/*
* 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)
{
struct super_block *sb = ip->i_sb;
struct jfs_inode_info *ji = JFS_IP(ip);
struct jfs_sb_info *sbi = JFS_SBI(sb);
int nblocks;
s64 blkno;
int rc = 0, i;
char *cp;
s32 nbytes, nb;
s32 bytes_to_write;
struct metapage *mp;
/*
* Quick check to see if this is an in-linable EA. Short EAs
* and empty EAs are all in-linable, provided the space exists.
*/
if (!ealist || size <= sizeof (ji->i_inline_ea)) {
if (!ea_write_inline(ip, ealist, size, ea))
return 0;
}
/* figure out how many blocks we need */
nblocks = (size + (sb->s_blocksize - 1)) >> sb->s_blocksize_bits;
/* Allocate new blocks to quota. */
if (DQUOT_ALLOC_BLOCK(ip, nblocks)) {
return -EDQUOT;
}
rc = dbAlloc(ip, INOHINT(ip), nblocks, &blkno);
if (rc) {
/*Rollback quota allocation. */
DQUOT_FREE_BLOCK(ip, nblocks);
return rc;
}
/*
* Now have nblocks worth of storage to stuff into the FEALIST.
* loop over the FEALIST copying data into the buffer one page at
* a time.
*/
cp = (char *) ealist;
nbytes = size;
for (i = 0; i < nblocks; i += sbi->nbperpage) {
/*
* Determine how many bytes for this request, and round up to
* the nearest aggregate block size
*/
nb = min(PSIZE, nbytes);
bytes_to_write =
((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
<< sb->s_blocksize_bits;
if (!(mp = get_metapage(ip, blkno + i, bytes_to_write, 1))) {
rc = -EIO;
goto failed;
}
memcpy(mp->data, cp, nb);
/*
* We really need a way to propagate errors for
* forced writes like this one. --hch
*
* (__write_metapage => release_metapage => flush_metapage)
*/
#ifdef _JFS_FIXME
if ((rc = flush_metapage(mp))) {
/*
* the write failed -- this means that the buffer
* is still assigned and the blocks are not being
* used. this seems like the best error recovery
* we can get ...
*/
goto failed;
}
#else
flush_metapage(mp);
#endif
cp += PSIZE;
nbytes -= nb;
}
ea->flag = DXD_EXTENT;
DXDsize(ea, le32_to_cpu(ealist->size));
DXDlength(ea, nblocks);
DXDaddress(ea, blkno);
/* Free up INLINE area */
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
return 0;
failed:
/* Rollback quota allocation. */
DQUOT_FREE_BLOCK(ip, nblocks);
dbFree(ip, blkno, nblocks);
return rc;
}
/*
* 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)
{
struct jfs_inode_info *ji = JFS_IP(ip);
int ea_size = sizeDXD(&ji->ea);
if (ea_size == 0) {
ealist->size = 0;
return 0;
}
/* Sanity Check */
if ((sizeDXD(&ji->ea) > sizeof (ji->i_inline_ea)))
return -EIO;
if (le32_to_cpu(((struct jfs_ea_list *) &ji->i_inline_ea)->size)
!= ea_size)
return -EIO;
memcpy(ealist, ji->i_inline_ea, ea_size);
return 0;
}
/*
* 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)
{
struct super_block *sb = ip->i_sb;
struct jfs_inode_info *ji = JFS_IP(ip);
struct jfs_sb_info *sbi = JFS_SBI(sb);
int nblocks;
s64 blkno;
char *cp = (char *) ealist;
int i;
int nbytes, nb;
s32 bytes_to_read;
struct metapage *mp;
/* quick check for in-line EA */
if (ji->ea.flag & DXD_INLINE)
return ea_read_inline(ip, ealist);
nbytes = sizeDXD(&ji->ea);
if (!nbytes) {
jfs_error(sb, "ea_read: nbytes is 0");
return -EIO;
}
/*
* Figure out how many blocks were allocated when this EA list was
* originally written to disk.
*/
nblocks = lengthDXD(&ji->ea) << sbi->l2nbperpage;
blkno = addressDXD(&ji->ea) << sbi->l2nbperpage;
/*
* I have found the disk blocks which were originally used to store
* the FEALIST. now i loop over each contiguous block copying the
* data into the buffer.
*/
for (i = 0; i < nblocks; i += sbi->nbperpage) {
/*
* Determine how many bytes for this request, and round up to
* the nearest aggregate block size
*/
nb = min(PSIZE, nbytes);
bytes_to_read =
((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
<< sb->s_blocksize_bits;
if (!(mp = read_metapage(ip, blkno + i, bytes_to_read, 1)))
return -EIO;
memcpy(cp, mp->data, nb);
release_metapage(mp);
cp += PSIZE;
nbytes -= nb;
}
return 0;
}
/*
* 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)
{
struct jfs_inode_info *ji = JFS_IP(inode);
struct super_block *sb = inode->i_sb;
int size;
int ea_size = sizeDXD(&ji->ea);
int blocks_needed, current_blocks;
s64 blkno;
int rc;
int quota_allocation = 0;
/* When fsck.jfs clears a bad ea, it doesn't clear the size */
if (ji->ea.flag == 0)
ea_size = 0;
if (ea_size == 0) {
if (min_size == 0) {
ea_buf->flag = 0;
ea_buf->max_size = 0;
ea_buf->xattr = NULL;
return 0;
}
if ((min_size <= sizeof (ji->i_inline_ea)) &&
(ji->mode2 & INLINEEA)) {
ea_buf->flag = EA_INLINE | EA_NEW;
ea_buf->max_size = sizeof (ji->i_inline_ea);
ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
DXDlength(&ea_buf->new_ea, 0);
DXDaddress(&ea_buf->new_ea, 0);
ea_buf->new_ea.flag = DXD_INLINE;
DXDsize(&ea_buf->new_ea, min_size);
return 0;
}
current_blocks = 0;
} else if (ji->ea.flag & DXD_INLINE) {
if (min_size <= sizeof (ji->i_inline_ea)) {
ea_buf->flag = EA_INLINE;
ea_buf->max_size = sizeof (ji->i_inline_ea);
ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
goto size_check;
}
current_blocks = 0;
} else {
if (!(ji->ea.flag & DXD_EXTENT)) {
jfs_error(sb, "ea_get: invalid ea.flag)");
return -EIO;
}
current_blocks = (ea_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
}
size = max(min_size, ea_size);
if (size > PSIZE) {
/*
* To keep the rest of the code simple. Allocate a
* contiguous buffer to work with
*/
ea_buf->xattr = kmalloc(size, GFP_KERNEL);
if (ea_buf->xattr == NULL)
return -ENOMEM;
ea_buf->flag = EA_MALLOC;
ea_buf->max_size = (size + sb->s_blocksize - 1) &
~(sb->s_blocksize - 1);
if (ea_size == 0)
return 0;
if ((rc = ea_read(inode, ea_buf->xattr))) {
kfree(ea_buf->xattr);
ea_buf->xattr = NULL;
return rc;
}
goto size_check;
}
blocks_needed = (min_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
if (blocks_needed > current_blocks) {
/* Allocate new blocks to quota. */
if (DQUOT_ALLOC_BLOCK(inode, blocks_needed))
return -EDQUOT;
quota_allocation = blocks_needed;
rc = dbAlloc(inode, INOHINT(inode), (s64) blocks_needed,
&blkno);
if (rc)
goto clean_up;
DXDlength(&ea_buf->new_ea, blocks_needed);
DXDaddress(&ea_buf->new_ea, blkno);
ea_buf->new_ea.flag = DXD_EXTENT;
DXDsize(&ea_buf->new_ea, min_size);
ea_buf->flag = EA_EXTENT | EA_NEW;
ea_buf->mp = get_metapage(inode, blkno,
blocks_needed << sb->s_blocksize_bits,
1);
if (ea_buf->mp == NULL) {
dbFree(inode, blkno, (s64) blocks_needed);
rc = -EIO;
goto clean_up;
}
ea_buf->xattr = ea_buf->mp->data;
ea_buf->max_size = (min_size + sb->s_blocksize - 1) &
~(sb->s_blocksize - 1);
if (ea_size == 0)
return 0;
if ((rc = ea_read(inode, ea_buf->xattr))) {
discard_metapage(ea_buf->mp);
dbFree(inode, blkno, (s64) blocks_needed);
goto clean_up;
}
goto size_check;
}
ea_buf->flag = EA_EXTENT;
ea_buf->mp = read_metapage(inode, addressDXD(&ji->ea),
lengthDXD(&ji->ea) << sb->s_blocksize_bits,
1);
if (ea_buf->mp == NULL) {
rc = -EIO;
goto clean_up;
}
ea_buf->xattr = ea_buf->mp->data;
ea_buf->max_size = (ea_size + sb->s_blocksize - 1) &
~(sb->s_blocksize - 1);
size_check:
if (EALIST_SIZE(ea_buf->xattr) != ea_size) {
printk(KERN_ERR "ea_get: invalid extended attribute\n");
dump_mem("xattr", ea_buf->xattr, ea_size);
ea_release(inode, ea_buf);
rc = -EIO;
goto clean_up;
}
return ea_size;
clean_up:
/* Rollback quota allocation */
if (quota_allocation)
DQUOT_FREE_BLOCK(inode, quota_allocation);
return (rc);
}
static void ea_release(struct inode *inode, struct ea_buffer *ea_buf)
{
if (ea_buf->flag & EA_MALLOC)
kfree(ea_buf->xattr);
else if (ea_buf->flag & EA_EXTENT) {
assert(ea_buf->mp);
release_metapage(ea_buf->mp);
if (ea_buf->flag & EA_NEW)
dbFree(inode, addressDXD(&ea_buf->new_ea),
lengthDXD(&ea_buf->new_ea));
}
}
static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
int new_size)
{
struct jfs_inode_info *ji = JFS_IP(inode);
unsigned long old_blocks, new_blocks;
int rc = 0;
if (new_size == 0) {
ea_release(inode, ea_buf);
ea_buf = NULL;
} else if (ea_buf->flag & EA_INLINE) {
assert(new_size <= sizeof (ji->i_inline_ea));
ji->mode2 &= ~INLINEEA;
ea_buf->new_ea.flag = DXD_INLINE;
DXDsize(&ea_buf->new_ea, new_size);
DXDaddress(&ea_buf->new_ea, 0);
DXDlength(&ea_buf->new_ea, 0);
} else if (ea_buf->flag & EA_MALLOC) {
rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
kfree(ea_buf->xattr);
} else if (ea_buf->flag & EA_NEW) {
/* We have already allocated a new dxd */
flush_metapage(ea_buf->mp);
} else {
/* ->xattr must point to original ea's metapage */
rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
discard_metapage(ea_buf->mp);
}
if (rc)
return rc;
old_blocks = new_blocks = 0;
if (ji->ea.flag & DXD_EXTENT) {
invalidate_dxd_metapages(inode, ji->ea);
old_blocks = lengthDXD(&ji->ea);
}
if (ea_buf) {
txEA(tid, inode, &ji->ea, &ea_buf->new_ea);
if (ea_buf->new_ea.flag & DXD_EXTENT) {
new_blocks = lengthDXD(&ea_buf->new_ea);
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
}
ji->ea = ea_buf->new_ea;
} else {
txEA(tid, inode, &ji->ea, NULL);
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
ji->ea.flag = 0;
ji->ea.size = 0;
}
/* If old blocks exist, they must be removed from quota allocation. */
if (old_blocks)
DQUOT_FREE_BLOCK(inode, old_blocks);
inode->i_ctime = CURRENT_TIME;
return 0;
}
/*
* can_set_system_xattr
*
* This code is specific to the system.* namespace. It contains policy
* which doesn't belong in the main xattr codepath.
*/
static int can_set_system_xattr(struct inode *inode, const char *name,
const void *value, size_t value_len)
{
#ifdef CONFIG_JFS_POSIX_ACL
struct posix_acl *acl;
int rc;
if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
return -EPERM;
/*
* POSIX_ACL_XATTR_ACCESS is tied to i_mode
*/
if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
acl = posix_acl_from_xattr(value, value_len);
if (IS_ERR(acl)) {
rc = PTR_ERR(acl);
printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
rc);
return rc;
}
if (acl) {
mode_t mode = inode->i_mode;
rc = posix_acl_equiv_mode(acl, &mode);
posix_acl_release(acl);
if (rc < 0) {
printk(KERN_ERR
"posix_acl_equiv_mode returned %d\n",
rc);
return rc;
}
inode->i_mode = mode;
mark_inode_dirty(inode);
}
/*
* We're changing the ACL. Get rid of the cached one
*/
acl =JFS_IP(inode)->i_acl;
if (acl != JFS_ACL_NOT_CACHED)
posix_acl_release(acl);
JFS_IP(inode)->i_acl = JFS_ACL_NOT_CACHED;
return 0;
} else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
acl = posix_acl_from_xattr(value, value_len);
if (IS_ERR(acl)) {
rc = PTR_ERR(acl);
printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
rc);
return rc;
}
posix_acl_release(acl);
/*
* We're changing the default ACL. Get rid of the cached one
*/
acl =JFS_IP(inode)->i_default_acl;
if (acl && (acl != JFS_ACL_NOT_CACHED))
posix_acl_release(acl);
JFS_IP(inode)->i_default_acl = JFS_ACL_NOT_CACHED;
return 0;
}
#endif /* CONFIG_JFS_POSIX_ACL */
return -EOPNOTSUPP;
}
static int can_set_xattr(struct inode *inode, const char *name,
const void *value, size_t value_len)
{
if (IS_RDONLY(inode))
return -EROFS;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
return -EPERM;
if(strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) == 0)
/*
* "system.*"
*/
return can_set_system_xattr(inode, name, value, value_len);
if(strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) == 0)
return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM);
#ifdef CONFIG_JFS_SECURITY
if (strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)
== 0)
return 0; /* Leave it to the security module */
#endif
if((strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) != 0) &&
(strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) != 0))
return -EOPNOTSUPP;
if (!S_ISREG(inode->i_mode) &&
(!S_ISDIR(inode->i_mode) || inode->i_mode &S_ISVTX))
return -EPERM;
return permission(inode, MAY_WRITE, NULL);
}
int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
const void *value, size_t value_len, int flags)
{
struct jfs_ea_list *ealist;
struct jfs_ea *ea, *old_ea = NULL, *next_ea = NULL;
struct ea_buffer ea_buf;
int old_ea_size = 0;
int xattr_size;
int new_size;
int namelen = strlen(name);
char *os2name = NULL;
int found = 0;
int rc;
int length;
if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
GFP_KERNEL);
if (!os2name)
return -ENOMEM;
strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
name = os2name;
namelen -= XATTR_OS2_PREFIX_LEN;
}
down_write(&JFS_IP(inode)->xattr_sem);
xattr_size = ea_get(inode, &ea_buf, 0);
if (xattr_size < 0) {
rc = xattr_size;
goto out;
}
again:
ealist = (struct jfs_ea_list *) ea_buf.xattr;
new_size = sizeof (struct jfs_ea_list);
if (xattr_size) {
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist);
ea = NEXT_EA(ea)) {
if ((namelen == ea->namelen) &&
(memcmp(name, ea->name, namelen) == 0)) {
found = 1;
if (flags & XATTR_CREATE) {
rc = -EEXIST;
goto release;
}
old_ea = ea;
old_ea_size = EA_SIZE(ea);
next_ea = NEXT_EA(ea);
} else
new_size += EA_SIZE(ea);
}
}
if (!found) {
if (flags & XATTR_REPLACE) {
rc = -ENODATA;
goto release;
}
if (value == NULL) {
rc = 0;
goto release;
}
}
if (value)
new_size += sizeof (struct jfs_ea) + namelen + 1 + value_len;
if (new_size > ea_buf.max_size) {
/*
* We need to allocate more space for merged ea list.
* We should only have loop to again: once.
*/
ea_release(inode, &ea_buf);
xattr_size = ea_get(inode, &ea_buf, new_size);
if (xattr_size < 0) {
rc = xattr_size;
goto out;
}
goto again;
}
/* Remove old ea of the same name */
if (found) {
/* number of bytes following target EA */
length = (char *) END_EALIST(ealist) - (char *) next_ea;
if (length > 0)
memmove(old_ea, next_ea, length);
xattr_size -= old_ea_size;
}
/* Add new entry to the end */
if (value) {
if (xattr_size == 0)
/* Completely new ea list */
xattr_size = sizeof (struct jfs_ea_list);
ea = (struct jfs_ea *) ((char *) ealist + xattr_size);
ea->flag = 0;
ea->namelen = namelen;
ea->valuelen = (cpu_to_le16(value_len));
memcpy(ea->name, name, namelen);
ea->name[namelen] = 0;
if (value_len)
memcpy(&ea->name[namelen + 1], value, value_len);
xattr_size += EA_SIZE(ea);
}
/* DEBUG - If we did this right, these number match */
if (xattr_size != new_size) {
printk(KERN_ERR
"jfs_xsetattr: xattr_size = %d, new_size = %d\n",
xattr_size, new_size);
rc = -EINVAL;
goto release;
}
/*
* If we're left with an empty list, there's no ea
*/
if (new_size == sizeof (struct jfs_ea_list))
new_size = 0;
ealist->size = cpu_to_le32(new_size);
rc = ea_put(tid, inode, &ea_buf, new_size);
goto out;
release:
ea_release(inode, &ea_buf);
out:
up_write(&JFS_IP(inode)->xattr_sem);
kfree(os2name);
return rc;
}
int jfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t value_len, int flags)
{
struct inode *inode = dentry->d_inode;
struct jfs_inode_info *ji = JFS_IP(inode);
int rc;
tid_t tid;
if ((rc = can_set_xattr(inode, name, value, value_len)))
return rc;
if (value == NULL) { /* empty EA, do not remove */
value = "";
value_len = 0;
}
tid = txBegin(inode->i_sb, 0);
down(&ji->commit_sem);
rc = __jfs_setxattr(tid, dentry->d_inode, name, value, value_len,
flags);
if (!rc)
rc = txCommit(tid, 1, &inode, 0);
txEnd(tid);
up(&ji->commit_sem);
return rc;
}
static int can_get_xattr(struct inode *inode, const char *name)
{
#ifdef CONFIG_JFS_SECURITY
if(strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) == 0)
return 0;
#endif
if(strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) == 0)
return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM);
if(strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) == 0)
return 0;
return permission(inode, MAY_READ, NULL);
}
ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
size_t buf_size)
{
struct jfs_ea_list *ealist;
struct jfs_ea *ea;
struct ea_buffer ea_buf;
int xattr_size;
ssize_t size;
int namelen = strlen(name);
char *os2name = NULL;
int rc;
char *value;
if ((rc = can_get_xattr(inode, name)))
return rc;
if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
GFP_KERNEL);
if (!os2name)
return -ENOMEM;
strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
name = os2name;
namelen -= XATTR_OS2_PREFIX_LEN;
}
down_read(&JFS_IP(inode)->xattr_sem);
xattr_size = ea_get(inode, &ea_buf, 0);
if (xattr_size < 0) {
size = xattr_size;
goto out;
}
if (xattr_size == 0)
goto not_found;
ealist = (struct jfs_ea_list *) ea_buf.xattr;
/* Find the named attribute */
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
if ((namelen == ea->namelen) &&
memcmp(name, ea->name, namelen) == 0) {
/* Found it */
size = le16_to_cpu(ea->valuelen);
if (!data)
goto release;
else if (size > buf_size) {
size = -ERANGE;
goto release;
}
value = ((char *) &ea->name) + ea->namelen + 1;
memcpy(data, value, size);
goto release;
}
not_found:
size = -ENODATA;
release:
ea_release(inode, &ea_buf);
out:
up_read(&JFS_IP(inode)->xattr_sem);
kfree(os2name);
return size;
}
ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
size_t buf_size)
{
int err;
err = __jfs_getxattr(dentry->d_inode, name, data, buf_size);
return err;
}
/*
* No special permissions are needed to list attributes except for trusted.*
*/
static inline int can_list(struct jfs_ea *ea)
{
return (strncmp(ea->name, XATTR_TRUSTED_PREFIX,
XATTR_TRUSTED_PREFIX_LEN) ||
capable(CAP_SYS_ADMIN));
}
ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
{
struct inode *inode = dentry->d_inode;
char *buffer;
ssize_t size = 0;
int xattr_size;
struct jfs_ea_list *ealist;
struct jfs_ea *ea;
struct ea_buffer ea_buf;
down_read(&JFS_IP(inode)->xattr_sem);
xattr_size = ea_get(inode, &ea_buf, 0);
if (xattr_size < 0) {
size = xattr_size;
goto out;
}
if (xattr_size == 0)
goto release;
ealist = (struct jfs_ea_list *) ea_buf.xattr;
/* compute required size of list */
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
if (can_list(ea))
size += name_size(ea) + 1;
}
if (!data)
goto release;
if (size > buf_size) {
size = -ERANGE;
goto release;
}
/* Copy attribute names to buffer */
buffer = data;
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
if (can_list(ea)) {
int namelen = copy_name(buffer, ea);
buffer += namelen + 1;
}
}
release:
ea_release(inode, &ea_buf);
out:
up_read(&JFS_IP(inode)->xattr_sem);
return size;
}
int jfs_removexattr(struct dentry *dentry, const char *name)
{
struct inode *inode = dentry->d_inode;
struct jfs_inode_info *ji = JFS_IP(inode);
int rc;
tid_t tid;
if ((rc = can_set_xattr(inode, name, NULL, 0)))
return rc;
tid = txBegin(inode->i_sb, 0);
down(&ji->commit_sem);
rc = __jfs_setxattr(tid, dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
if (!rc)
rc = txCommit(tid, 1, &inode, 0);
txEnd(tid);
up(&ji->commit_sem);
return rc;
}
#ifdef CONFIG_JFS_SECURITY
int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir)
{
int rc;
size_t len;
void *value;
char *suffix;
char *name;
rc = security_inode_init_security(inode, dir, &suffix, &value, &len);
if (rc) {
if (rc == -EOPNOTSUPP)
return 0;
return rc;
}
name = kmalloc(XATTR_SECURITY_PREFIX_LEN + 1 + strlen(suffix),
GFP_NOFS);
if (!name) {
rc = -ENOMEM;
goto kmalloc_failed;
}
strcpy(name, XATTR_SECURITY_PREFIX);
strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
rc = __jfs_setxattr(tid, inode, name, value, len, 0);
kfree(name);
kmalloc_failed:
kfree(suffix);
kfree(value);
return rc;
}
#endif
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