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 (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN) {
  77                 gossip_err("Invalid key length (%d)\n",
  78                            (int)strlen(name));
  79                 return -EINVAL;
  80         }
  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         down_write(&orangefs_inode->xattr_sem);
 173         new_op = op_alloc(ORANGEFS_VFS_OP_REMOVEXATTR);
 174         if (!new_op)
 175                 goto out_unlock;
 176
 177         new_op->upcall.req.removexattr.refn = orangefs_inode->refn;
 178         /*
 179          * NOTE: Although keys are meant to be NULL terminated
 180          * textual strings, I am going to explicitly pass the
 181          * length just in case we change this later on...
 182          */
 183         strcpy(new_op->upcall.req.removexattr.key, name);
 184         new_op->upcall.req.removexattr.key_sz = strlen(name) + 1;
 185
 186         gossip_debug(GOSSIP_XATTR_DEBUG,
 187                      "orangefs_inode_removexattr: key %s, key_sz %d\n",
 188                      (char *)new_op->upcall.req.removexattr.key,
 189                      (int)new_op->upcall.req.removexattr.key_sz);
 190
 191         ret = service_operation(new_op,
 192                                 "orangefs_inode_removexattr",
 193                                 get_interruptible_flag(inode));
 194         if (ret == -ENOENT) {
 195                 /*
 196                  * Request to replace a non-existent attribute is an error.
 197                  */
 198                 if (flags & XATTR_REPLACE)
 199                         ret = -ENODATA;
 200                 else
 201                         ret = 0;
 202         }
 203
 204         gossip_debug(GOSSIP_XATTR_DEBUG,
 205                      "orangefs_inode_removexattr: returning %d\n", ret);
 206
 207         op_release(new_op);
 208 out_unlock:
 209         up_write(&orangefs_inode->xattr_sem);
 210         return ret;
 211 }
 212
 213 /*
 214  * Tries to set an attribute for a given key on a file.
 215  *
 216  * Returns a -ve number on error and 0 on success.  Key is text, but value
 217  * can be binary!
 218  */
 219 int orangefs_inode_setxattr(struct inode *inode, const char *name,
 220                             const void *value, size_t size, int flags)
 221 {
 222         struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 223         struct orangefs_kernel_op_s *new_op;
 224         int internal_flag = 0;
 225         int ret = -ENOMEM;
 226
 227         gossip_debug(GOSSIP_XATTR_DEBUG,
 228                      "%s: name %s, buffer_size %zd\n",
 229                      __func__, name, size);
 230
 231         if (size >= ORANGEFS_MAX_XATTR_VALUELEN ||
 232             flags < 0) {
 233                 gossip_err("orangefs_inode_setxattr: bogus values of size(%d), flags(%d)\n",
 234                            (int)size,
 235                            flags);
 236                 return -EINVAL;
 237         }
 238
 239         internal_flag = convert_to_internal_xattr_flags(flags);
 240
 241         if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN) {
 242                 gossip_err
 243                     ("orangefs_inode_setxattr: bogus key size (%d)\n",
 244                      (int)(strlen(name)));
 245                 return -EINVAL;
 246         }
 247
 248         /* This is equivalent to a removexattr */
 249         if (size == 0 && value == NULL) {
 250                 gossip_debug(GOSSIP_XATTR_DEBUG,
 251                              "removing xattr (%s)\n",
 252                              name);
 253                 return orangefs_inode_removexattr(inode, name, flags);
 254         }
 255
 256         gossip_debug(GOSSIP_XATTR_DEBUG,
 257                      "setxattr on inode %pU, name %s\n",
 258                      get_khandle_from_ino(inode),
 259                      name);
 260
 261         down_write(&orangefs_inode->xattr_sem);
 262         new_op = op_alloc(ORANGEFS_VFS_OP_SETXATTR);
 263         if (!new_op)
 264                 goto out_unlock;
 265
 266
 267         new_op->upcall.req.setxattr.refn = orangefs_inode->refn;
 268         new_op->upcall.req.setxattr.flags = internal_flag;
 269         /*
 270          * NOTE: Although keys are meant to be NULL terminated textual
 271          * strings, I am going to explicitly pass the length just in
 272          * case we change this later on...
 273          */
 274         strcpy(new_op->upcall.req.setxattr.keyval.key, name);
 275         new_op->upcall.req.setxattr.keyval.key_sz = strlen(name) + 1;
 276         memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
 277         new_op->upcall.req.setxattr.keyval.val_sz = size;
 278
 279         gossip_debug(GOSSIP_XATTR_DEBUG,
 280                      "orangefs_inode_setxattr: key %s, key_sz %d "
 281                      " value size %zd\n",
 282                      (char *)new_op->upcall.req.setxattr.keyval.key,
 283                      (int)new_op->upcall.req.setxattr.keyval.key_sz,
 284                      size);
 285
 286         ret = service_operation(new_op,
 287                                 "orangefs_inode_setxattr",
 288                                 get_interruptible_flag(inode));
 289
 290         gossip_debug(GOSSIP_XATTR_DEBUG,
 291                      "orangefs_inode_setxattr: returning %d\n",
 292                      ret);
 293
 294         /* when request is serviced properly, free req op struct */
 295         op_release(new_op);
 296 out_unlock:
 297         up_write(&orangefs_inode->xattr_sem);
 298         return ret;
 299 }
 300
 301 /*
 302  * Tries to get a specified object's keys into a user-specified buffer of a
 303  * given size.  Note that like the previous instances of xattr routines, this
 304  * also allows you to pass in a NULL pointer and 0 size to probe the size for
 305  * subsequent memory allocations. Thus our return value is always the size of
 306  * all the keys unless there were errors in fetching the keys!
 307  */
 308 ssize_t orangefs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 309 {
 310         struct inode *inode = dentry->d_inode;
 311         struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 312         struct orangefs_kernel_op_s *new_op;
 313         __u64 token = ORANGEFS_ITERATE_START;
 314         ssize_t ret = -ENOMEM;
 315         ssize_t total = 0;
 316         int count_keys = 0;
 317         int key_size;
 318         int i = 0;
 319         int returned_count = 0;
 320
 321         if (size > 0 && buffer == NULL) {
 322                 gossip_err("%s: bogus NULL pointers\n", __func__);
 323                 return -EINVAL;
 324         }
 325
 326         down_read(&orangefs_inode->xattr_sem);
 327         new_op = op_alloc(ORANGEFS_VFS_OP_LISTXATTR);
 328         if (!new_op)
 329                 goto out_unlock;
 330
 331         if (buffer && size > 0)
 332                 memset(buffer, 0, size);
 333
 334 try_again:
 335         key_size = 0;
 336         new_op->upcall.req.listxattr.refn = orangefs_inode->refn;
 337         new_op->upcall.req.listxattr.token = token;
 338         new_op->upcall.req.listxattr.requested_count =
 339             (size == 0) ? 0 : ORANGEFS_MAX_XATTR_LISTLEN;
 340         ret = service_operation(new_op, __func__,
 341                                 get_interruptible_flag(inode));
 342         if (ret != 0)
 343                 goto done;
 344
 345         if (size == 0) {
 346                 /*
 347                  * This is a bit of a big upper limit, but I did not want to
 348                  * spend too much time getting this correct, since users end
 349                  * up allocating memory rather than us...
 350                  */
 351                 total = new_op->downcall.resp.listxattr.returned_count *
 352                         ORANGEFS_MAX_XATTR_NAMELEN;
 353                 goto done;
 354         }
 355
 356         returned_count = new_op->downcall.resp.listxattr.returned_count;
 357         if (returned_count < 0 ||
 358             returned_count >= ORANGEFS_MAX_XATTR_LISTLEN) {
 359                 gossip_err("%s: impossible value for returned_count:%d:\n",
 360                 __func__,
 361                 returned_count);
 362                 ret = -EIO;
 363                 goto done;
 364         }
 365
 366         /*
 367          * Check to see how much can be fit in the buffer. Fit only whole keys.
 368          */
 369         for (i = 0; i < returned_count; i++) {
 370                 if (new_op->downcall.resp.listxattr.lengths[i] < 0 ||
 371                     new_op->downcall.resp.listxattr.lengths[i] >
 372                     ORANGEFS_MAX_XATTR_NAMELEN) {
 373                         gossip_err("%s: impossible value for lengths[%d]\n",
 374                             __func__,
 375                             new_op->downcall.resp.listxattr.lengths[i]);
 376                         ret = -EIO;
 377                         goto done;
 378                 }
 379                 if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
 380                         goto done;
 381
 382                 /*
 383                  * Since many dumb programs try to setxattr() on our reserved
 384                  * xattrs this is a feeble attempt at defeating those by not
 385                  * listing them in the output of listxattr.. sigh
 386                  */
 387                 if (is_reserved_key(new_op->downcall.resp.listxattr.key +
 388                                     key_size,
 389                                     new_op->downcall.resp.
 390                                         listxattr.lengths[i])) {
 391                         gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s\n",
 392                                         i, new_op->downcall.resp.listxattr.key +
 393                                                 key_size);
 394                         memcpy(buffer + total,
 395                                 new_op->downcall.resp.listxattr.key + key_size,
 396                                 new_op->downcall.resp.listxattr.lengths[i]);
 397                         total += new_op->downcall.resp.listxattr.lengths[i];
 398                         count_keys++;
 399                 } else {
 400                         gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s\n",
 401                                         i, new_op->downcall.resp.listxattr.key +
 402                                                 key_size);
 403                 }
 404                 key_size += new_op->downcall.resp.listxattr.lengths[i];
 405         }
 406
 407         /*
 408          * Since the buffer was large enough, we might have to continue
 409          * fetching more keys!
 410          */
 411         token = new_op->downcall.resp.listxattr.token;
 412         if (token != ORANGEFS_ITERATE_END)
 413                 goto try_again;
 414
 415 done:
 416         gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
 417                      " [size of buffer %ld] (filled in %d keys)\n",
 418                      __func__,
 419                      ret ? (int)ret : (int)total,
 420                      (long)size,
 421                      count_keys);
 422         op_release(new_op);
 423         if (ret == 0)
 424                 ret = total;
 425 out_unlock:
 426         up_read(&orangefs_inode->xattr_sem);
 427         return ret;
 428 }
 429
 430 static int orangefs_xattr_set_default(const struct xattr_handler *handler,
 431                                       struct dentry *unused,
 432                                       struct inode *inode,
 433                                       const char *name,
 434                                       const void *buffer,
 435                                       size_t size,
 436                                       int flags)
 437 {
 438         return orangefs_inode_setxattr(inode, name, buffer, size, flags);
 439 }
 440
 441 static int orangefs_xattr_get_default(const struct xattr_handler *handler,
 442                                       struct dentry *unused,
 443                                       struct inode *inode,
 444                                       const char *name,
 445                                       void *buffer,
 446                                       size_t size)
 447 {
 448         return orangefs_inode_getxattr(inode, name, buffer, size);
 449
 450 }
 451
 452 static struct xattr_handler orangefs_xattr_default_handler = {
 453         .prefix = "",  /* match any name => handlers called with full name */
 454         .get = orangefs_xattr_get_default,
 455         .set = orangefs_xattr_set_default,
 456 };
 457
 458 const struct xattr_handler *orangefs_xattr_handlers[] = {
 459         &posix_acl_access_xattr_handler,
 460         &posix_acl_default_xattr_handler,
 461         &orangefs_xattr_default_handler,
 462         NULL
 463 };