fs/xfs/linux-2.6/xfs_xattr.c

   1 /*
   2  * Copyright (C) 2008 Christoph Hellwig.
   3  * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 #include "xfs.h"
  20 #include "xfs_da_btree.h"
  21 #include "xfs_bmap_btree.h"
  22 #include "xfs_inode.h"
  23 #include "xfs_attr.h"
  24 #include "xfs_attr_leaf.h"
  25 #include "xfs_acl.h"
  26 #include "xfs_vnodeops.h"
  27
  28 #include <linux/posix_acl_xattr.h>
  29 #include <linux/xattr.h>
  30
  31
  32 static int
  33 __xfs_xattr_get(struct inode *inode, const char *name,
  34                 void *value, size_t size, int xflags)
  35 {
  36         struct xfs_inode *ip = XFS_I(inode);
  37         int error, asize = size;
  38
  39         if (strcmp(name, "") == 0)
  40                 return -EINVAL;
  41
  42         /* Convert Linux syscall to XFS internal ATTR flags */
  43         if (!size) {
  44                 xflags |= ATTR_KERNOVAL;
  45                 value = NULL;
  46         }
  47
  48         error = -xfs_attr_get(ip, name, value, &asize, xflags);
  49         if (error)
  50                 return error;
  51         return asize;
  52 }
  53
  54 static int
  55 __xfs_xattr_set(struct inode *inode, const char *name, const void *value,
  56                 size_t size, int flags, int xflags)
  57 {
  58         struct xfs_inode *ip = XFS_I(inode);
  59
  60         if (strcmp(name, "") == 0)
  61                 return -EINVAL;
  62
  63         /* Convert Linux syscall to XFS internal ATTR flags */
  64         if (flags & XATTR_CREATE)
  65                 xflags |= ATTR_CREATE;
  66         if (flags & XATTR_REPLACE)
  67                 xflags |= ATTR_REPLACE;
  68
  69         if (!value)
  70                 return -xfs_attr_remove(ip, name, xflags);
  71         return -xfs_attr_set(ip, name, (void *)value, size, xflags);
  72 }
  73
  74 static int
  75 xfs_xattr_user_get(struct inode *inode, const char *name,
  76                 void *value, size_t size)
  77 {
  78         return __xfs_xattr_get(inode, name, value, size, 0);
  79 }
  80
  81 static int
  82 xfs_xattr_user_set(struct inode *inode, const char *name,
  83                 const void *value, size_t size, int flags)
  84 {
  85         return __xfs_xattr_set(inode, name, value, size, flags, 0);
  86 }
  87
  88 static struct xattr_handler xfs_xattr_user_handler = {
  89         .prefix = XATTR_USER_PREFIX,
  90         .get    = xfs_xattr_user_get,
  91         .set    = xfs_xattr_user_set,
  92 };
  93
  94
  95 static int
  96 xfs_xattr_trusted_get(struct inode *inode, const char *name,
  97                 void *value, size_t size)
  98 {
  99         return __xfs_xattr_get(inode, name, value, size, ATTR_ROOT);
 100 }
 101
 102 static int
 103 xfs_xattr_trusted_set(struct inode *inode, const char *name,
 104                 const void *value, size_t size, int flags)
 105 {
 106         return __xfs_xattr_set(inode, name, value, size, flags, ATTR_ROOT);
 107 }
 108
 109 static struct xattr_handler xfs_xattr_trusted_handler = {
 110         .prefix = XATTR_TRUSTED_PREFIX,
 111         .get    = xfs_xattr_trusted_get,
 112         .set    = xfs_xattr_trusted_set,
 113 };
 114
 115
 116 static int
 117 xfs_xattr_secure_get(struct inode *inode, const char *name,
 118                 void *value, size_t size)
 119 {
 120         return __xfs_xattr_get(inode, name, value, size, ATTR_SECURE);
 121 }
 122
 123 static int
 124 xfs_xattr_secure_set(struct inode *inode, const char *name,
 125                 const void *value, size_t size, int flags)
 126 {
 127         return __xfs_xattr_set(inode, name, value, size, flags, ATTR_SECURE);
 128 }
 129
 130 static struct xattr_handler xfs_xattr_security_handler = {
 131         .prefix = XATTR_SECURITY_PREFIX,
 132         .get    = xfs_xattr_secure_get,
 133         .set    = xfs_xattr_secure_set,
 134 };
 135
 136
 137 struct xattr_handler *xfs_xattr_handlers[] = {
 138         &xfs_xattr_user_handler,
 139         &xfs_xattr_trusted_handler,
 140         &xfs_xattr_security_handler,
 141 #ifdef CONFIG_XFS_POSIX_ACL
 142         &xfs_xattr_system_handler,
 143 #endif
 144         NULL
 145 };
 146
 147 static unsigned int xfs_xattr_prefix_len(int flags)
 148 {
 149         if (flags & XFS_ATTR_SECURE)
 150                 return sizeof("security");
 151         else if (flags & XFS_ATTR_ROOT)
 152                 return sizeof("trusted");
 153         else
 154                 return sizeof("user");
 155 }
 156
 157 static const char *xfs_xattr_prefix(int flags)
 158 {
 159         if (flags & XFS_ATTR_SECURE)
 160                 return xfs_xattr_security_handler.prefix;
 161         else if (flags & XFS_ATTR_ROOT)
 162                 return xfs_xattr_trusted_handler.prefix;
 163         else
 164                 return xfs_xattr_user_handler.prefix;
 165 }
 166
 167 static int
 168 xfs_xattr_put_listent(struct xfs_attr_list_context *context, int flags,
 169                 char *name, int namelen, int valuelen, char *value)
 170 {
 171         unsigned int prefix_len = xfs_xattr_prefix_len(flags);
 172         char *offset;
 173         int arraytop;
 174
 175         ASSERT(context->count >= 0);
 176
 177         /*
 178          * Only show root namespace entries if we are actually allowed to
 179          * see them.
 180          */
 181         if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN))
 182                 return 0;
 183
 184         arraytop = context->count + prefix_len + namelen + 1;
 185         if (arraytop > context->firstu) {
 186                 context->count = -1;    /* insufficient space */
 187                 return 1;
 188         }
 189         offset = (char *)context->alist + context->count;
 190         strncpy(offset, xfs_xattr_prefix(flags), prefix_len);
 191         offset += prefix_len;
 192         strncpy(offset, name, namelen);                 /* real name */
 193         offset += namelen;
 194         *offset = '\0';
 195         context->count += prefix_len + namelen + 1;
 196         return 0;
 197 }
 198
 199 static int
 200 xfs_xattr_put_listent_sizes(struct xfs_attr_list_context *context, int flags,
 201                 char *name, int namelen, int valuelen, char *value)
 202 {
 203         context->count += xfs_xattr_prefix_len(flags) + namelen + 1;
 204         return 0;
 205 }
 206
 207 static int
 208 list_one_attr(const char *name, const size_t len, void *data,
 209                 size_t size, ssize_t *result)
 210 {
 211         char *p = data + *result;
 212
 213         *result += len;
 214         if (!size)
 215                 return 0;
 216         if (*result > size)
 217                 return -ERANGE;
 218
 219         strcpy(p, name);
 220         return 0;
 221 }
 222
 223 ssize_t
 224 xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
 225 {
 226         struct xfs_attr_list_context context;
 227         struct attrlist_cursor_kern cursor = { 0 };
 228         struct inode            *inode = dentry->d_inode;
 229         int                     error;
 230
 231         /*
 232          * First read the regular on-disk attributes.
 233          */
 234         memset(&context, 0, sizeof(context));
 235         context.dp = XFS_I(inode);
 236         context.cursor = &cursor;
 237         context.resynch = 1;
 238         context.alist = data;
 239         context.bufsize = size;
 240         context.firstu = context.bufsize;
 241
 242         if (size)
 243                 context.put_listent = xfs_xattr_put_listent;
 244         else
 245                 context.put_listent = xfs_xattr_put_listent_sizes;
 246
 247         xfs_attr_list_int(&context);
 248         if (context.count < 0)
 249                 return -ERANGE;
 250
 251         /*
 252          * Then add the two synthetic ACL attributes.
 253          */
 254         if (posix_acl_access_exists(inode)) {
 255                 error = list_one_attr(POSIX_ACL_XATTR_ACCESS,
 256                                 strlen(POSIX_ACL_XATTR_ACCESS) + 1,
 257                                 data, size, &context.count);
 258                 if (error)
 259                         return error;
 260         }
 261
 262         if (posix_acl_default_exists(inode)) {
 263                 error = list_one_attr(POSIX_ACL_XATTR_DEFAULT,
 264                                 strlen(POSIX_ACL_XATTR_DEFAULT) + 1,
 265                                 data, size, &context.count);
 266                 if (error)
 267                         return error;
 268         }
 269
 270         return context.count;
 271 }