fs/orangefs/xattr.c

   1 /*
   2  * (C) 2001 Clemson University and The University of Chicago
   3  *
   4  * See COPYING in top-level directory.
   5  */
   6
   7 /*
   8  *  Linux VFS extended attribute operations.
   9  */
  10
  11 #include "protocol.h"
  12 #include "orangefs-kernel.h"
  13 #include "orangefs-bufmap.h"
  14 #include <linux/posix_acl_xattr.h>
  15 #include <linux/xattr.h>
  16
  17
  18 #define SYSTEM_ORANGEFS_KEY "system.pvfs2."
  19 #define SYSTEM_ORANGEFS_KEY_LEN 13
  20
  21 /*
  22  * this function returns
  23  *   0 if the key corresponding to name is not meant to be printed as part
  24  *     of a listxattr.
  25  *   1 if the key corresponding to name is meant to be returned as part of
  26  *     a listxattr.
  27  * The ones that start SYSTEM_ORANGEFS_KEY are the ones to avoid printing.
  28  */
  29 static int is_reserved_key(const char *key, size_t size)
  30 {
  31
  32         if (size < SYSTEM_ORANGEFS_KEY_LEN)
  33                 return 1;
  34
  35         return strncmp(key, SYSTEM_ORANGEFS_KEY, SYSTEM_ORANGEFS_KEY_LEN) ?  1 : 0;
  36 }
  37
  38 static inline int convert_to_internal_xattr_flags(int setxattr_flags)
  39 {
  40         int internal_flag = 0;
  41
  42         if (setxattr_flags & XATTR_REPLACE) {
  43                 /* Attribute must exist! */
  44                 internal_flag = ORANGEFS_XATTR_REPLACE;
  45         } else if (setxattr_flags & XATTR_CREATE) {
  46                 /* Attribute must not exist */
  47                 internal_flag = ORANGEFS_XATTR_CREATE;
  48         }
  49         return internal_flag;
  50 }
  51
  52
  53 /*
  54  * Tries to get a specified key's attributes of a given
  55  * file into a user-specified buffer. Note that the getxattr
  56  * interface allows for the users to probe the size of an
  57  * extended attribute by passing in a value of 0 to size.
  58  * Thus our return value is always the size of the attribute
  59  * unless the key does not exist for the file and/or if
  60  * there were errors in fetching the attribute value.
  61  */
  62 ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
  63                                 void *buffer, size_t size)
  64 {
  65         struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
  66         struct orangefs_kernel_op_s *new_op = NULL;
  67         ssize_t ret = -ENOMEM;
  68         ssize_t length = 0;
  69         int fsuid;
  70         int fsgid;
  71
  72         gossip_debug(GOSSIP_XATTR_DEBUG,
  73                      "%s: name %s, buffer_size %zd\n",
  74                      __func__, name, size);
  75
  76         if (S_ISLNK(inode->i_mode))
  77                 return -EOPNOTSUPP;
  78
  79         if (strlen(name) > ORANGEFS_MAX_XATTR_NAMELEN)
  80                 return -EINVAL;
  81
  82         fsuid = from_kuid(&init_user_ns, current_fsuid());
  83         fsgid = from_kgid(&init_user_ns, current_fsgid());
  84
  85         gossip_debug(GOSSIP_XATTR_DEBUG,
  86                      "getxattr on inode %pU, name %s "
  87                      "(uid %o, gid %o)\n",
  88                      get_khandle_from_ino(inode),
  89                      name,
  90                      fsuid,
  91                      fsgid);
  92
  93         down_read(&orangefs_inode->xattr_sem);
  94
  95         new_op = op_alloc(ORANGEFS_VFS_OP_GETXATTR);
  96         if (!new_op)
  97                 goto out_unlock;
  98
  99         new_op->upcall.req.getxattr.refn = orangefs_inode->refn;
 100         strcpy(new_op->upcall.req.getxattr.key, name);
 101
 102         /*
 103          * NOTE: Although keys are meant to be NULL terminated textual
 104          * strings, I am going to explicitly pass the length just in case
 105          * we change this later on...
 106          */
 107         new_op->upcall.req.getxattr.key_sz = strlen(name) + 1;
 108
 109         ret = service_operation(new_op, "orangefs_inode_getxattr",
 110                                 get_interruptible_flag(inode));
 111         if (ret != 0) {
 112                 if (ret == -ENOENT) {
 113                         ret = -ENODATA;
 114                         gossip_debug(GOSSIP_XATTR_DEBUG,
 115                                      "orangefs_inode_getxattr: inode %pU key %s"
 116                                      " does not exist!\n",
 117                                      get_khandle_from_ino(inode),
 118                                      (char *)new_op->upcall.req.getxattr.key);
 119                 }
 120                 goto out_release_op;
 121         }
 122
 123         /*
 124          * Length returned includes null terminator.
 125          */
 126         length = new_op->downcall.resp.getxattr.val_sz;
 127
 128         /*
 129          * Just return the length of the queried attribute.
 130          */
 131         if (size == 0) {
 132                 ret = length;
 133                 goto out_release_op;
 134         }
 135
 136         /*
 137          * Check to see if key length is > provided buffer size.
 138          */
 139         if (length > size) {
 140                 ret = -ERANGE;
 141                 goto out_release_op;
 142         }
 143
 144         memcpy(buffer, new_op->downcall.resp.getxattr.val, length);
 145         memset(buffer + length, 0, size - length);
 146         gossip_debug(GOSSIP_XATTR_DEBUG,
 147              "orangefs_inode_getxattr: inode %pU "
 148              "key %s key_sz %d, val_len %d\n",
 149              get_khandle_from_ino(inode),
 150              (char *)new_op->
 151                 upcall.req.getxattr.key,
 152                      (int)new_op->
 153                 upcall.req.getxattr.key_sz,
 154              (int)ret);
 155
 156         ret = length;
 157
 158 out_release_op:
 159         op_release(new_op);
 160 out_unlock:
 161         up_read(&orangefs_inode->xattr_sem);
 162         return ret;
 163 }
 164
 165 static int orangefs_inode_removexattr(struct inode *inode, const char *name,
 166                                       int flags)
 167 {
 168         struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 169         struct orangefs_kernel_op_s *new_op = NULL;
 170         int ret = -ENOMEM;
 171
 172         if (strlen(name) > ORANGEFS_MAX_XATTR_NAMELEN)
 173                 return -EINVAL;
 174
 175         down_write(&orangefs_inode->xattr_sem);
 176         new_op = op_alloc(ORANGEFS_VFS_OP_REMOVEXATTR);
 177         if (!new_op)
 178                 goto out_unlock;
 179
 180         new_op->upcall.req.removexattr.refn = orangefs_inode->refn;
 181         /*
 182          * NOTE: Although keys are meant to be NULL terminated
 183          * textual strings, I am going to explicitly pass the
 184          * length just in case we change this later on...
 185          */
 186         strcpy(new_op->upcall.req.removexattr.key, name);
 187         new_op->upcall.req.removexattr.key_sz = strlen(name) + 1;
 188
 189         gossip_debug(GOSSIP_XATTR_DEBUG,
 190                      "orangefs_inode_removexattr: key %s, key_sz %d\n",
 191                      (char *)new_op->upcall.req.removexattr.key,
 192                      (int)new_op->upcall.req.removexattr.key_sz);
 193
 194         ret = service_operation(new_op,
 195                                 "orangefs_inode_removexattr",
 196                                 get_interruptible_flag(inode));
 197         if (ret == -ENOENT) {
 198                 /*
 199                  * Request to replace a non-existent attribute is an error.
 200                  */
 201                 if (flags & XATTR_REPLACE)
 202                         ret = -ENODATA;
 203                 else
 204                         ret = 0;
 205         }
 206
 207         gossip_debug(GOSSIP_XATTR_DEBUG,
 208                      "orangefs_inode_removexattr: returning %d\n", ret);
 209
 210         op_release(new_op);
 211 out_unlock:
 212         up_write(&orangefs_inode->xattr_sem);
 213         return ret;
 214 }
 215
 216 /*
 217  * Tries to set an attribute for a given key on a file.
 218  *
 219  * Returns a -ve number on error and 0 on success.  Key is text, but value
 220  * can be binary!
 221  */
 222 int orangefs_inode_setxattr(struct inode *inode, const char *name,
 223                             const void *value, size_t size, int flags)
 224 {
 225         struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 226         struct orangefs_kernel_op_s *new_op;
 227         int internal_flag = 0;
 228         int ret = -ENOMEM;
 229
 230         gossip_debug(GOSSIP_XATTR_DEBUG,
 231                      "%s: name %s, buffer_size %zd\n",
 232                      __func__, name, size);
 233
 234         if (size > ORANGEFS_MAX_XATTR_VALUELEN)
 235                 return -EINVAL;
 236         if (strlen(name) > ORANGEFS_MAX_XATTR_NAMELEN)
 237                 return -EINVAL;
 238
 239         internal_flag = convert_to_internal_xattr_flags(flags);
 240
 241         /* This is equivalent to a removexattr */
 242         if (size == 0 && value == NULL) {
 243                 gossip_debug(GOSSIP_XATTR_DEBUG,
 244                              "removing xattr (%s)\n",
 245                              name);
 246                 return orangefs_inode_removexattr(inode, name, flags);
 247         }
 248
 249         gossip_debug(GOSSIP_XATTR_DEBUG,
 250                      "setxattr on inode %pU, name %s\n",
 251                      get_khandle_from_ino(inode),
 252                      name);
 253
 254         down_write(&orangefs_inode->xattr_sem);
 255         new_op = op_alloc(ORANGEFS_VFS_OP_SETXATTR);
 256         if (!new_op)
 257                 goto out_unlock;
 258
 259
 260         new_op->upcall.req.setxattr.refn = orangefs_inode->refn;
 261         new_op->upcall.req.setxattr.flags = internal_flag;
 262         /*
 263          * NOTE: Although keys are meant to be NULL terminated textual
 264          * strings, I am going to explicitly pass the length just in
 265          * case we change this later on...
 266          */
 267         strcpy(new_op->upcall.req.setxattr.keyval.key, name);
 268         new_op->upcall.req.setxattr.keyval.key_sz = strlen(name) + 1;
 269         memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
 270         new_op->upcall.req.setxattr.keyval.val_sz = size;
 271
 272         gossip_debug(GOSSIP_XATTR_DEBUG,
 273                      "orangefs_inode_setxattr: key %s, key_sz %d "
 274                      " value size %zd\n",
 275                      (char *)new_op->upcall.req.setxattr.keyval.key,
 276                      (int)new_op->upcall.req.setxattr.keyval.key_sz,
 277                      size);
 278
 279         ret = service_operation(new_op,
 280                                 "orangefs_inode_setxattr",
 281                                 get_interruptible_flag(inode));
 282
 283         gossip_debug(GOSSIP_XATTR_DEBUG,
 284                      "orangefs_inode_setxattr: returning %d\n",
 285                      ret);
 286
 287         /* when request is serviced properly, free req op struct */
 288         op_release(new_op);
 289 out_unlock:
 290         up_write(&orangefs_inode->xattr_sem);
 291         return ret;
 292 }
 293
 294 /*
 295  * Tries to get a specified object's keys into a user-specified buffer of a
 296  * given size.  Note that like the previous instances of xattr routines, this
 297  * also allows you to pass in a NULL pointer and 0 size to probe the size for
 298  * subsequent memory allocations. Thus our return value is always the size of
 299  * all the keys unless there were errors in fetching the keys!
 300  */
 301 ssize_t orangefs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 302 {
 303         struct inode *inode = dentry->d_inode;
 304         struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 305         struct orangefs_kernel_op_s *new_op;
 306         __u64 token = ORANGEFS_ITERATE_START;
 307         ssize_t ret = -ENOMEM;
 308         ssize_t total = 0;
 309         int count_keys = 0;
 310         int key_size;
 311         int i = 0;
 312         int returned_count = 0;
 313
 314         if (size > 0 && buffer == NULL) {
 315                 gossip_err("%s: bogus NULL pointers\n", __func__);
 316                 return -EINVAL;
 317         }
 318
 319         down_read(&orangefs_inode->xattr_sem);
 320         new_op = op_alloc(ORANGEFS_VFS_OP_LISTXATTR);
 321         if (!new_op)
 322                 goto out_unlock;
 323
 324         if (buffer && size > 0)
 325                 memset(buffer, 0, size);
 326
 327 try_again:
 328         key_size = 0;
 329         new_op->upcall.req.listxattr.refn = orangefs_inode->refn;
 330         new_op->upcall.req.listxattr.token = token;
 331         new_op->upcall.req.listxattr.requested_count =
 332             (size == 0) ? 0 : ORANGEFS_MAX_XATTR_LISTLEN;
 333         ret = service_operation(new_op, __func__,
 334                                 get_interruptible_flag(inode));
 335         if (ret != 0)
 336                 goto done;
 337
 338         if (size == 0) {
 339                 /*
 340                  * This is a bit of a big upper limit, but I did not want to
 341                  * spend too much time getting this correct, since users end
 342                  * up allocating memory rather than us...
 343                  */
 344                 total = new_op->downcall.resp.listxattr.returned_count *
 345                         ORANGEFS_MAX_XATTR_NAMELEN;
 346                 goto done;
 347         }
 348
 349         returned_count = new_op->downcall.resp.listxattr.returned_count;
 350         if (returned_count < 0 ||
 351             returned_count > ORANGEFS_MAX_XATTR_LISTLEN) {
 352                 gossip_err("%s: impossible value for returned_count:%d:\n",
 353                 __func__,
 354                 returned_count);
 355                 ret = -EIO;
 356                 goto done;
 357         }
 358
 359         /*
 360          * Check to see how much can be fit in the buffer. Fit only whole keys.
 361          */
 362         for (i = 0; i < returned_count; i++) {
 363                 if (new_op->downcall.resp.listxattr.lengths[i] < 0 ||
 364                     new_op->downcall.resp.listxattr.lengths[i] >
 365                     ORANGEFS_MAX_XATTR_NAMELEN) {
 366                         gossip_err("%s: impossible value for lengths[%d]\n",
 367                             __func__,
 368                             new_op->downcall.resp.listxattr.lengths[i]);
 369                         ret = -EIO;
 370                         goto done;
 371                 }
 372                 if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
 373                         goto done;
 374
 375                 /*
 376                  * Since many dumb programs try to setxattr() on our reserved
 377                  * xattrs this is a feeble attempt at defeating those by not
 378                  * listing them in the output of listxattr.. sigh
 379                  */
 380                 if (is_reserved_key(new_op->downcall.resp.listxattr.key +
 381                                     key_size,
 382                                     new_op->downcall.resp.
 383                                         listxattr.lengths[i])) {
 384                         gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s\n",
 385                                         i, new_op->downcall.resp.listxattr.key +
 386                                                 key_size);
 387                         memcpy(buffer + total,
 388                                 new_op->downcall.resp.listxattr.key + key_size,
 389                                 new_op->downcall.resp.listxattr.lengths[i]);
 390                         total += new_op->downcall.resp.listxattr.lengths[i];
 391                         count_keys++;
 392                 } else {
 393                         gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s\n",
 394                                         i, new_op->downcall.resp.listxattr.key +
 395                                                 key_size);
 396                 }
 397                 key_size += new_op->downcall.resp.listxattr.lengths[i];
 398         }
 399
 400         /*
 401          * Since the buffer was large enough, we might have to continue
 402          * fetching more keys!
 403          */
 404         token = new_op->downcall.resp.listxattr.token;
 405         if (token != ORANGEFS_ITERATE_END)
 406                 goto try_again;
 407
 408 done:
 409         gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
 410                      " [size of buffer %ld] (filled in %d keys)\n",
 411                      __func__,
 412                      ret ? (int)ret : (int)total,
 413                      (long)size,
 414                      count_keys);
 415         op_release(new_op);
 416         if (ret == 0)
 417                 ret = total;
 418 out_unlock:
 419         up_read(&orangefs_inode->xattr_sem);
 420         return ret;
 421 }
 422
 423 static int orangefs_xattr_set_default(const struct xattr_handler *handler,
 424                                       struct dentry *unused,
 425                                       struct inode *inode,
 426                                       const char *name,
 427                                       const void *buffer,
 428                                       size_t size,
 429                                       int flags)
 430 {
 431         return orangefs_inode_setxattr(inode, name, buffer, size, flags);
 432 }
 433
 434 static int orangefs_xattr_get_default(const struct xattr_handler *handler,
 435                                       struct dentry *unused,
 436                                       struct inode *inode,
 437                                       const char *name,
 438                                       void *buffer,
 439                                       size_t size)
 440 {
 441         return orangefs_inode_getxattr(inode, name, buffer, size);
 442
 443 }
 444
 445 static struct xattr_handler orangefs_xattr_default_handler = {
 446         .prefix = "",  /* match any name => handlers called with full name */
 447         .get = orangefs_xattr_get_default,
 448         .set = orangefs_xattr_set_default,
 449 };
 450
 451 const struct xattr_handler *orangefs_xattr_handlers[] = {
 452         &posix_acl_access_xattr_handler,
 453         &posix_acl_default_xattr_handler,
 454         &orangefs_xattr_default_handler,
 455         NULL
 456 };