lib/bootconfig.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Extra Boot Config
   4  * Masami Hiramatsu <mhiramat@kernel.org>
   5  */
   6
   7 #define pr_fmt(fmt)    "bootconfig: " fmt
   8
   9 #include <linux/bootconfig.h>
  10 #include <linux/bug.h>
  11 #include <linux/ctype.h>
  12 #include <linux/errno.h>
  13 #include <linux/kernel.h>
  14 #include <linux/memblock.h>
  15 #include <linux/printk.h>
  16 #include <linux/string.h>
  17
  18 /*
  19  * Extra Boot Config (XBC) is given as tree-structured ascii text of
  20  * key-value pairs on memory.
  21  * xbc_parse() parses the text to build a simple tree. Each tree node is
  22  * simply a key word or a value. A key node may have a next key node or/and
  23  * a child node (both key and value). A value node may have a next value
  24  * node (for array).
  25  */
  26
  27 static struct xbc_node *xbc_nodes __initdata;
  28 static int xbc_node_num __initdata;
  29 static char *xbc_data __initdata;
  30 static size_t xbc_data_size __initdata;
  31 static struct xbc_node *last_parent __initdata;
  32 static const char *xbc_err_msg __initdata;
  33 static int xbc_err_pos __initdata;
  34
  35 static int __init xbc_parse_error(const char *msg, const char *p)
  36 {
  37         xbc_err_msg = msg;
  38         xbc_err_pos = (int)(p - xbc_data);
  39
  40         return -EINVAL;
  41 }
  42
  43 /**
  44  * xbc_root_node() - Get the root node of extended boot config
  45  *
  46  * Return the address of root node of extended boot config. If the
  47  * extended boot config is not initiized, return NULL.
  48  */
  49 struct xbc_node * __init xbc_root_node(void)
  50 {
  51         if (unlikely(!xbc_data))
  52                 return NULL;
  53
  54         return xbc_nodes;
  55 }
  56
  57 /**
  58  * xbc_node_index() - Get the index of XBC node
  59  * @node: A target node of getting index.
  60  *
  61  * Return the index number of @node in XBC node list.
  62  */
  63 int __init xbc_node_index(struct xbc_node *node)
  64 {
  65         return node - &xbc_nodes[0];
  66 }
  67
  68 /**
  69  * xbc_node_get_parent() - Get the parent XBC node
  70  * @node: An XBC node.
  71  *
  72  * Return the parent node of @node. If the node is top node of the tree,
  73  * return NULL.
  74  */
  75 struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
  76 {
  77         return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
  78 }
  79
  80 /**
  81  * xbc_node_get_child() - Get the child XBC node
  82  * @node: An XBC node.
  83  *
  84  * Return the first child node of @node. If the node has no child, return
  85  * NULL.
  86  */
  87 struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
  88 {
  89         return node->child ? &xbc_nodes[node->child] : NULL;
  90 }
  91
  92 /**
  93  * xbc_node_get_next() - Get the next sibling XBC node
  94  * @node: An XBC node.
  95  *
  96  * Return the NEXT sibling node of @node. If the node has no next sibling,
  97  * return NULL. Note that even if this returns NULL, it doesn't mean @node
  98  * has no siblings. (You also has to check whether the parent's child node
  99  * is @node or not.)
 100  */
 101 struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
 102 {
 103         return node->next ? &xbc_nodes[node->next] : NULL;
 104 }
 105
 106 /**
 107  * xbc_node_get_data() - Get the data of XBC node
 108  * @node: An XBC node.
 109  *
 110  * Return the data (which is always a null terminated string) of @node.
 111  * If the node has invalid data, warn and return NULL.
 112  */
 113 const char * __init xbc_node_get_data(struct xbc_node *node)
 114 {
 115         int offset = node->data & ~XBC_VALUE;
 116
 117         if (WARN_ON(offset >= xbc_data_size))
 118                 return NULL;
 119
 120         return xbc_data + offset;
 121 }
 122
 123 static bool __init
 124 xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
 125 {
 126         const char *p = xbc_node_get_data(node);
 127         int len = strlen(p);
 128
 129         if (strncmp(*prefix, p, len))
 130                 return false;
 131
 132         p = *prefix + len;
 133         if (*p == '.')
 134                 p++;
 135         else if (*p != '\0')
 136                 return false;
 137         *prefix = p;
 138
 139         return true;
 140 }
 141
 142 /**
 143  * xbc_node_find_child() - Find a child node which matches given key
 144  * @parent: An XBC node.
 145  * @key: A key string.
 146  *
 147  * Search a node under @parent which matches @key. The @key can contain
 148  * several words jointed with '.'. If @parent is NULL, this searches the
 149  * node from whole tree. Return NULL if no node is matched.
 150  */
 151 struct xbc_node * __init
 152 xbc_node_find_child(struct xbc_node *parent, const char *key)
 153 {
 154         struct xbc_node *node;
 155
 156         if (parent)
 157                 node = xbc_node_get_child(parent);
 158         else
 159                 node = xbc_root_node();
 160
 161         while (node && xbc_node_is_key(node)) {
 162                 if (!xbc_node_match_prefix(node, &key))
 163                         node = xbc_node_get_next(node);
 164                 else if (*key != '\0')
 165                         node = xbc_node_get_child(node);
 166                 else
 167                         break;
 168         }
 169
 170         return node;
 171 }
 172
 173 /**
 174  * xbc_node_find_value() - Find a value node which matches given key
 175  * @parent: An XBC node.
 176  * @key: A key string.
 177  * @vnode: A container pointer of found XBC node.
 178  *
 179  * Search a value node under @parent whose (parent) key node matches @key,
 180  * store it in *@vnode, and returns the value string.
 181  * The @key can contain several words jointed with '.'. If @parent is NULL,
 182  * this searches the node from whole tree. Return the value string if a
 183  * matched key found, return NULL if no node is matched.
 184  * Note that this returns 0-length string and stores NULL in *@vnode if the
 185  * key has no value. And also it will return the value of the first entry if
 186  * the value is an array.
 187  */
 188 const char * __init
 189 xbc_node_find_value(struct xbc_node *parent, const char *key,
 190                     struct xbc_node **vnode)
 191 {
 192         struct xbc_node *node = xbc_node_find_child(parent, key);
 193
 194         if (!node || !xbc_node_is_key(node))
 195                 return NULL;
 196
 197         node = xbc_node_get_child(node);
 198         if (node && !xbc_node_is_value(node))
 199                 return NULL;
 200
 201         if (vnode)
 202                 *vnode = node;
 203
 204         return node ? xbc_node_get_data(node) : "";
 205 }
 206
 207 /**
 208  * xbc_node_compose_key_after() - Compose partial key string of the XBC node
 209  * @root: Root XBC node
 210  * @node: Target XBC node.
 211  * @buf: A buffer to store the key.
 212  * @size: The size of the @buf.
 213  *
 214  * Compose the partial key of the @node into @buf, which is starting right
 215  * after @root (@root is not included.) If @root is NULL, this returns full
 216  * key words of @node.
 217  * Returns the total length of the key stored in @buf. Returns -EINVAL
 218  * if @node is NULL or @root is not the ancestor of @node or @root is @node,
 219  * or returns -ERANGE if the key depth is deeper than max depth.
 220  * This is expected to be used with xbc_find_node() to list up all (child)
 221  * keys under given key.
 222  */
 223 int __init xbc_node_compose_key_after(struct xbc_node *root,
 224                                       struct xbc_node *node,
 225                                       char *buf, size_t size)
 226 {
 227         u16 keys[XBC_DEPTH_MAX];
 228         int depth = 0, ret = 0, total = 0;
 229
 230         if (!node || node == root)
 231                 return -EINVAL;
 232
 233         if (xbc_node_is_value(node))
 234                 node = xbc_node_get_parent(node);
 235
 236         while (node && node != root) {
 237                 keys[depth++] = xbc_node_index(node);
 238                 if (depth == XBC_DEPTH_MAX)
 239                         return -ERANGE;
 240                 node = xbc_node_get_parent(node);
 241         }
 242         if (!node && root)
 243                 return -EINVAL;
 244
 245         while (--depth >= 0) {
 246                 node = xbc_nodes + keys[depth];
 247                 ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),
 248                                depth ? "." : "");
 249                 if (ret < 0)
 250                         return ret;
 251                 if (ret > size) {
 252                         size = 0;
 253                 } else {
 254                         size -= ret;
 255                         buf += ret;
 256                 }
 257                 total += ret;
 258         }
 259
 260         return total;
 261 }
 262
 263 /**
 264  * xbc_node_find_next_leaf() - Find the next leaf node under given node
 265  * @root: An XBC root node
 266  * @node: An XBC node which starts from.
 267  *
 268  * Search the next leaf node (which means the terminal key node) of @node
 269  * under @root node (including @root node itself).
 270  * Return the next node or NULL if next leaf node is not found.
 271  */
 272 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
 273                                                  struct xbc_node *node)
 274 {
 275         if (unlikely(!xbc_data))
 276                 return NULL;
 277
 278         if (!node) {    /* First try */
 279                 node = root;
 280                 if (!node)
 281                         node = xbc_nodes;
 282         } else {
 283                 if (node == root)       /* @root was a leaf, no child node. */
 284                         return NULL;
 285
 286                 while (!node->next) {
 287                         node = xbc_node_get_parent(node);
 288                         if (node == root)
 289                                 return NULL;
 290                         /* User passed a node which is not uder parent */
 291                         if (WARN_ON(!node))
 292                                 return NULL;
 293                 }
 294                 node = xbc_node_get_next(node);
 295         }
 296
 297         while (node && !xbc_node_is_leaf(node))
 298                 node = xbc_node_get_child(node);
 299
 300         return node;
 301 }
 302
 303 /**
 304  * xbc_node_find_next_key_value() - Find the next key-value pair nodes
 305  * @root: An XBC root node
 306  * @leaf: A container pointer of XBC node which starts from.
 307  *
 308  * Search the next leaf node (which means the terminal key node) of *@leaf
 309  * under @root node. Returns the value and update *@leaf if next leaf node
 310  * is found, or NULL if no next leaf node is found.
 311  * Note that this returns 0-length string if the key has no value, or
 312  * the value of the first entry if the value is an array.
 313  */
 314 const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
 315                                                  struct xbc_node **leaf)
 316 {
 317         /* tip must be passed */
 318         if (WARN_ON(!leaf))
 319                 return NULL;
 320
 321         *leaf = xbc_node_find_next_leaf(root, *leaf);
 322         if (!*leaf)
 323                 return NULL;
 324         if ((*leaf)->child)
 325                 return xbc_node_get_data(xbc_node_get_child(*leaf));
 326         else
 327                 return "";      /* No value key */
 328 }
 329
 330 /* XBC parse and tree build */
 331
 332 static struct xbc_node * __init xbc_add_node(char *data, u32 flag)
 333 {
 334         struct xbc_node *node;
 335         unsigned long offset;
 336
 337         if (xbc_node_num == XBC_NODE_MAX)
 338                 return NULL;
 339
 340         node = &xbc_nodes[xbc_node_num++];
 341         offset = data - xbc_data;
 342         node->data = (u16)offset;
 343         if (WARN_ON(offset >= XBC_DATA_MAX))
 344                 return NULL;
 345         node->data |= flag;
 346         node->child = 0;
 347         node->next = 0;
 348
 349         return node;
 350 }
 351
 352 static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
 353 {
 354         while (node->next)
 355                 node = xbc_node_get_next(node);
 356
 357         return node;
 358 }
 359
 360 static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
 361 {
 362         struct xbc_node *sib, *node = xbc_add_node(data, flag);
 363
 364         if (node) {
 365                 if (!last_parent) {
 366                         node->parent = XBC_NODE_MAX;
 367                         sib = xbc_last_sibling(xbc_nodes);
 368                         sib->next = xbc_node_index(node);
 369                 } else {
 370                         node->parent = xbc_node_index(last_parent);
 371                         if (!last_parent->child) {
 372                                 last_parent->child = xbc_node_index(node);
 373                         } else {
 374                                 sib = xbc_node_get_child(last_parent);
 375                                 sib = xbc_last_sibling(sib);
 376                                 sib->next = xbc_node_index(node);
 377                         }
 378                 }
 379         } else
 380                 xbc_parse_error("Too many nodes", data);
 381
 382         return node;
 383 }
 384
 385 static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
 386 {
 387         struct xbc_node *node = xbc_add_sibling(data, flag);
 388
 389         if (node)
 390                 last_parent = node;
 391
 392         return node;
 393 }
 394
 395 static inline __init bool xbc_valid_keyword(char *key)
 396 {
 397         if (key[0] == '\0')
 398                 return false;
 399
 400         while (isalnum(*key) || *key == '-' || *key == '_')
 401                 key++;
 402
 403         return *key == '\0';
 404 }
 405
 406 static char *skip_comment(char *p)
 407 {
 408         char *ret;
 409
 410         ret = strchr(p, '\n');
 411         if (!ret)
 412                 ret = p + strlen(p);
 413         else
 414                 ret++;
 415
 416         return ret;
 417 }
 418
 419 static char *skip_spaces_until_newline(char *p)
 420 {
 421         while (isspace(*p) && *p != '\n')
 422                 p++;
 423         return p;
 424 }
 425
 426 static int __init __xbc_open_brace(void)
 427 {
 428         /* Mark the last key as open brace */
 429         last_parent->next = XBC_NODE_MAX;
 430
 431         return 0;
 432 }
 433
 434 static int __init __xbc_close_brace(char *p)
 435 {
 436         struct xbc_node *node;
 437
 438         if (!last_parent || last_parent->next != XBC_NODE_MAX)
 439                 return xbc_parse_error("Unexpected closing brace", p);
 440
 441         node = last_parent;
 442         node->next = 0;
 443         do {
 444                 node = xbc_node_get_parent(node);
 445         } while (node && node->next != XBC_NODE_MAX);
 446         last_parent = node;
 447
 448         return 0;
 449 }
 450
 451 /*
 452  * Return delimiter or error, no node added. As same as lib/cmdline.c,
 453  * you can use " around spaces, but can't escape " for value.
 454  */
 455 static int __init __xbc_parse_value(char **__v, char **__n)
 456 {
 457         char *p, *v = *__v;
 458         int c, quotes = 0;
 459
 460         v = skip_spaces(v);
 461         while (*v == '#') {
 462                 v = skip_comment(v);
 463                 v = skip_spaces(v);
 464         }
 465         if (*v == '"' || *v == '\'') {
 466                 quotes = *v;
 467                 v++;
 468         }
 469         p = v - 1;
 470         while ((c = *++p)) {
 471                 if (!isprint(c) && !isspace(c))
 472                         return xbc_parse_error("Non printable value", p);
 473                 if (quotes) {
 474                         if (c != quotes)
 475                                 continue;
 476                         quotes = 0;
 477                         *p++ = '\0';
 478                         p = skip_spaces_until_newline(p);
 479                         c = *p;
 480                         if (c && !strchr(",;\n#}", c))
 481                                 return xbc_parse_error("No value delimiter", p);
 482                         if (*p)
 483                                 p++;
 484                         break;
 485                 }
 486                 if (strchr(",;\n#}", c)) {
 487                         v = strim(v);
 488                         *p++ = '\0';
 489                         break;
 490                 }
 491         }
 492         if (quotes)
 493                 return xbc_parse_error("No closing quotes", p);
 494         if (c == '#') {
 495                 p = skip_comment(p);
 496                 c = '\n';       /* A comment must be treated as a newline */
 497         }
 498         *__n = p;
 499         *__v = v;
 500
 501         return c;
 502 }
 503
 504 static int __init xbc_parse_array(char **__v)
 505 {
 506         struct xbc_node *node;
 507         char *next;
 508         int c = 0;
 509
 510         do {
 511                 c = __xbc_parse_value(__v, &next);
 512                 if (c < 0)
 513                         return c;
 514
 515                 node = xbc_add_sibling(*__v, XBC_VALUE);
 516                 if (!node)
 517                         return -ENOMEM;
 518                 *__v = next;
 519         } while (c == ',');
 520         node->next = 0;
 521
 522         return c;
 523 }
 524
 525 static inline __init
 526 struct xbc_node *find_match_node(struct xbc_node *node, char *k)
 527 {
 528         while (node) {
 529                 if (!strcmp(xbc_node_get_data(node), k))
 530                         break;
 531                 node = xbc_node_get_next(node);
 532         }
 533         return node;
 534 }
 535
 536 static int __init __xbc_add_key(char *k)
 537 {
 538         struct xbc_node *node, *child;
 539
 540         if (!xbc_valid_keyword(k))
 541                 return xbc_parse_error("Invalid keyword", k);
 542
 543         if (unlikely(xbc_node_num == 0))
 544                 goto add_node;
 545
 546         if (!last_parent)       /* the first level */
 547                 node = find_match_node(xbc_nodes, k);
 548         else {
 549                 child = xbc_node_get_child(last_parent);
 550                 if (child && xbc_node_is_value(child))
 551                         return xbc_parse_error("Subkey is mixed with value", k);
 552                 node = find_match_node(child, k);
 553         }
 554
 555         if (node)
 556                 last_parent = node;
 557         else {
 558 add_node:
 559                 node = xbc_add_child(k, XBC_KEY);
 560                 if (!node)
 561                         return -ENOMEM;
 562         }
 563         return 0;
 564 }
 565
 566 static int __init __xbc_parse_keys(char *k)
 567 {
 568         char *p;
 569         int ret;
 570
 571         k = strim(k);
 572         while ((p = strchr(k, '.'))) {
 573                 *p++ = '\0';
 574                 ret = __xbc_add_key(k);
 575                 if (ret)
 576                         return ret;
 577                 k = p;
 578         }
 579
 580         return __xbc_add_key(k);
 581 }
 582
 583 static int __init xbc_parse_kv(char **k, char *v, int op)
 584 {
 585         struct xbc_node *prev_parent = last_parent;
 586         struct xbc_node *child;
 587         char *next;
 588         int c, ret;
 589
 590         ret = __xbc_parse_keys(*k);
 591         if (ret)
 592                 return ret;
 593
 594         child = xbc_node_get_child(last_parent);
 595         if (child) {
 596                 if (xbc_node_is_key(child))
 597                         return xbc_parse_error("Value is mixed with subkey", v);
 598                 else if (op == '=')
 599                         return xbc_parse_error("Value is redefined", v);
 600         }
 601
 602         c = __xbc_parse_value(&v, &next);
 603         if (c < 0)
 604                 return c;
 605
 606         if (!xbc_add_sibling(v, XBC_VALUE))
 607                 return -ENOMEM;
 608
 609         if (c == ',') { /* Array */
 610                 c = xbc_parse_array(&next);
 611                 if (c < 0)
 612                         return c;
 613         }
 614
 615         last_parent = prev_parent;
 616
 617         if (c == '}') {
 618                 ret = __xbc_close_brace(next - 1);
 619                 if (ret < 0)
 620                         return ret;
 621         }
 622
 623         *k = next;
 624
 625         return 0;
 626 }
 627
 628 static int __init xbc_parse_key(char **k, char *n)
 629 {
 630         struct xbc_node *prev_parent = last_parent;
 631         int ret;
 632
 633         *k = strim(*k);
 634         if (**k != '\0') {
 635                 ret = __xbc_parse_keys(*k);
 636                 if (ret)
 637                         return ret;
 638                 last_parent = prev_parent;
 639         }
 640         *k = n;
 641
 642         return 0;
 643 }
 644
 645 static int __init xbc_open_brace(char **k, char *n)
 646 {
 647         int ret;
 648
 649         ret = __xbc_parse_keys(*k);
 650         if (ret)
 651                 return ret;
 652         *k = n;
 653
 654         return __xbc_open_brace();
 655 }
 656
 657 static int __init xbc_close_brace(char **k, char *n)
 658 {
 659         int ret;
 660
 661         ret = xbc_parse_key(k, n);
 662         if (ret)
 663                 return ret;
 664         /* k is updated in xbc_parse_key() */
 665
 666         return __xbc_close_brace(n - 1);
 667 }
 668
 669 static int __init xbc_verify_tree(void)
 670 {
 671         int i, depth, len, wlen;
 672         struct xbc_node *n, *m;
 673
 674         /* Empty tree */
 675         if (xbc_node_num == 0) {
 676                 xbc_parse_error("Empty config", xbc_data);
 677                 return -ENOENT;
 678         }
 679
 680         for (i = 0; i < xbc_node_num; i++) {
 681                 if (xbc_nodes[i].next > xbc_node_num) {
 682                         return xbc_parse_error("No closing brace",
 683                                 xbc_node_get_data(xbc_nodes + i));
 684                 }
 685         }
 686
 687         /* Key tree limitation check */
 688         n = &xbc_nodes[0];
 689         depth = 1;
 690         len = 0;
 691
 692         while (n) {
 693                 wlen = strlen(xbc_node_get_data(n)) + 1;
 694                 len += wlen;
 695                 if (len > XBC_KEYLEN_MAX)
 696                         return xbc_parse_error("Too long key length",
 697                                 xbc_node_get_data(n));
 698
 699                 m = xbc_node_get_child(n);
 700                 if (m && xbc_node_is_key(m)) {
 701                         n = m;
 702                         depth++;
 703                         if (depth > XBC_DEPTH_MAX)
 704                                 return xbc_parse_error("Too many key words",
 705                                                 xbc_node_get_data(n));
 706                         continue;
 707                 }
 708                 len -= wlen;
 709                 m = xbc_node_get_next(n);
 710                 while (!m) {
 711                         n = xbc_node_get_parent(n);
 712                         if (!n)
 713                                 break;
 714                         len -= strlen(xbc_node_get_data(n)) + 1;
 715                         depth--;
 716                         m = xbc_node_get_next(n);
 717                 }
 718                 n = m;
 719         }
 720
 721         return 0;
 722 }
 723
 724 /**
 725  * xbc_destroy_all() - Clean up all parsed bootconfig
 726  *
 727  * This clears all data structures of parsed bootconfig on memory.
 728  * If you need to reuse xbc_init() with new boot config, you can
 729  * use this.
 730  */
 731 void __init xbc_destroy_all(void)
 732 {
 733         xbc_data = NULL;
 734         xbc_data_size = 0;
 735         xbc_node_num = 0;
 736         memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
 737         xbc_nodes = NULL;
 738 }
 739
 740 /**
 741  * xbc_init() - Parse given XBC file and build XBC internal tree
 742  * @buf: boot config text
 743  * @emsg: A pointer of const char * to store the error message
 744  * @epos: A pointer of int to store the error position
 745  *
 746  * This parses the boot config text in @buf. @buf must be a
 747  * null terminated string and smaller than XBC_DATA_MAX.
 748  * Return the number of stored nodes (>0) if succeeded, or -errno
 749  * if there is any error.
 750  * In error cases, @emsg will be updated with an error message and
 751  * @epos will be updated with the error position which is the byte offset
 752  * of @buf. If the error is not a parser error, @epos will be -1.
 753  */
 754 int __init xbc_init(char *buf, const char **emsg, int *epos)
 755 {
 756         char *p, *q;
 757         int ret, c;
 758
 759         if (epos)
 760                 *epos = -1;
 761
 762         if (xbc_data) {
 763                 if (emsg)
 764                         *emsg = "Bootconfig is already initialized";
 765                 return -EBUSY;
 766         }
 767
 768         ret = strlen(buf);
 769         if (ret > XBC_DATA_MAX - 1 || ret == 0) {
 770                 if (emsg)
 771                         *emsg = ret ? "Config data is too big" :
 772                                 "Config data is empty";
 773                 return -ERANGE;
 774         }
 775
 776         xbc_nodes = memblock_alloc(sizeof(struct xbc_node) * XBC_NODE_MAX,
 777                                    SMP_CACHE_BYTES);
 778         if (!xbc_nodes) {
 779                 if (emsg)
 780                         *emsg = "Failed to allocate bootconfig nodes";
 781                 return -ENOMEM;
 782         }
 783         memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX);
 784         xbc_data = buf;
 785         xbc_data_size = ret + 1;
 786         last_parent = NULL;
 787
 788         p = buf;
 789         do {
 790                 q = strpbrk(p, "{}=+;\n#");
 791                 if (!q) {
 792                         p = skip_spaces(p);
 793                         if (*p != '\0')
 794                                 ret = xbc_parse_error("No delimiter", p);
 795                         break;
 796                 }
 797
 798                 c = *q;
 799                 *q++ = '\0';
 800                 switch (c) {
 801                 case '+':
 802                         if (*q++ != '=') {
 803                                 ret = xbc_parse_error("Wrong '+' operator",
 804                                                         q - 2);
 805                                 break;
 806                         }
 807                         /* Fall through */
 808                 case '=':
 809                         ret = xbc_parse_kv(&p, q, c);
 810                         break;
 811                 case '{':
 812                         ret = xbc_open_brace(&p, q);
 813                         break;
 814                 case '#':
 815                         q = skip_comment(q);
 816                         /* fall through */
 817                 case ';':
 818                 case '\n':
 819                         ret = xbc_parse_key(&p, q);
 820                         break;
 821                 case '}':
 822                         ret = xbc_close_brace(&p, q);
 823                         break;
 824                 }
 825         } while (!ret);
 826
 827         if (!ret)
 828                 ret = xbc_verify_tree();
 829
 830         if (ret < 0) {
 831                 if (epos)
 832                         *epos = xbc_err_pos;
 833                 if (emsg)
 834                         *emsg = xbc_err_msg;
 835                 xbc_destroy_all();
 836         } else
 837                 ret = xbc_node_num;
 838
 839         return ret;
 840 }
 841
 842 /**
 843  * xbc_debug_dump() - Dump current XBC node list
 844  *
 845  * Dump the current XBC node list on printk buffer for debug.
 846  */
 847 void __init xbc_debug_dump(void)
 848 {
 849         int i;
 850
 851         for (i = 0; i < xbc_node_num; i++) {
 852                 pr_debug("[%d] %s (%s) .next=%d, .child=%d .parent=%d\n", i,
 853                         xbc_node_get_data(xbc_nodes + i),
 854                         xbc_node_is_value(xbc_nodes + i) ? "value" : "key",
 855                         xbc_nodes[i].next, xbc_nodes[i].child,
 856                         xbc_nodes[i].parent);
 857         }
 858 }