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