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 static int open_brace[XBC_DEPTH_MAX] __initdata;
  35 static int brace_index __initdata;
  36
  37 static int __init xbc_parse_error(const char *msg, const char *p)
  38 {
  39         xbc_err_msg = msg;
  40         xbc_err_pos = (int)(p - xbc_data);
  41
  42         return -EINVAL;
  43 }
  44
  45 /**
  46  * xbc_root_node() - Get the root node of extended boot config
  47  *
  48  * Return the address of root node of extended boot config. If the
  49  * extended boot config is not initiized, return NULL.
  50  */
  51 struct xbc_node * __init xbc_root_node(void)
  52 {
  53         if (unlikely(!xbc_data))
  54                 return NULL;
  55
  56         return xbc_nodes;
  57 }
  58
  59 /**
  60  * xbc_node_index() - Get the index of XBC node
  61  * @node: A target node of getting index.
  62  *
  63  * Return the index number of @node in XBC node list.
  64  */
  65 int __init xbc_node_index(struct xbc_node *node)
  66 {
  67         return node - &xbc_nodes[0];
  68 }
  69
  70 /**
  71  * xbc_node_get_parent() - Get the parent XBC node
  72  * @node: An XBC node.
  73  *
  74  * Return the parent node of @node. If the node is top node of the tree,
  75  * return NULL.
  76  */
  77 struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node)
  78 {
  79         return node->parent == XBC_NODE_MAX ? NULL : &xbc_nodes[node->parent];
  80 }
  81
  82 /**
  83  * xbc_node_get_child() - Get the child XBC node
  84  * @node: An XBC node.
  85  *
  86  * Return the first child node of @node. If the node has no child, return
  87  * NULL.
  88  */
  89 struct xbc_node * __init xbc_node_get_child(struct xbc_node *node)
  90 {
  91         return node->child ? &xbc_nodes[node->child] : NULL;
  92 }
  93
  94 /**
  95  * xbc_node_get_next() - Get the next sibling XBC node
  96  * @node: An XBC node.
  97  *
  98  * Return the NEXT sibling node of @node. If the node has no next sibling,
  99  * return NULL. Note that even if this returns NULL, it doesn't mean @node
 100  * has no siblings. (You also has to check whether the parent's child node
 101  * is @node or not.)
 102  */
 103 struct xbc_node * __init xbc_node_get_next(struct xbc_node *node)
 104 {
 105         return node->next ? &xbc_nodes[node->next] : NULL;
 106 }
 107
 108 /**
 109  * xbc_node_get_data() - Get the data of XBC node
 110  * @node: An XBC node.
 111  *
 112  * Return the data (which is always a null terminated string) of @node.
 113  * If the node has invalid data, warn and return NULL.
 114  */
 115 const char * __init xbc_node_get_data(struct xbc_node *node)
 116 {
 117         int offset = node->data & ~XBC_VALUE;
 118
 119         if (WARN_ON(offset >= xbc_data_size))
 120                 return NULL;
 121
 122         return xbc_data + offset;
 123 }
 124
 125 static bool __init
 126 xbc_node_match_prefix(struct xbc_node *node, const char **prefix)
 127 {
 128         const char *p = xbc_node_get_data(node);
 129         int len = strlen(p);
 130
 131         if (strncmp(*prefix, p, len))
 132                 return false;
 133
 134         p = *prefix + len;
 135         if (*p == '.')
 136                 p++;
 137         else if (*p != '\0')
 138                 return false;
 139         *prefix = p;
 140
 141         return true;
 142 }
 143
 144 /**
 145  * xbc_node_find_child() - Find a child node which matches given key
 146  * @parent: An XBC node.
 147  * @key: A key string.
 148  *
 149  * Search a node under @parent which matches @key. The @key can contain
 150  * several words jointed with '.'. If @parent is NULL, this searches the
 151  * node from whole tree. Return NULL if no node is matched.
 152  */
 153 struct xbc_node * __init
 154 xbc_node_find_child(struct xbc_node *parent, const char *key)
 155 {
 156         struct xbc_node *node;
 157
 158         if (parent)
 159                 node = xbc_node_get_child(parent);
 160         else
 161                 node = xbc_root_node();
 162
 163         while (node && xbc_node_is_key(node)) {
 164                 if (!xbc_node_match_prefix(node, &key))
 165                         node = xbc_node_get_next(node);
 166                 else if (*key != '\0')
 167                         node = xbc_node_get_child(node);
 168                 else
 169                         break;
 170         }
 171
 172         return node;
 173 }
 174
 175 /**
 176  * xbc_node_find_value() - Find a value node which matches given key
 177  * @parent: An XBC node.
 178  * @key: A key string.
 179  * @vnode: A container pointer of found XBC node.
 180  *
 181  * Search a value node under @parent whose (parent) key node matches @key,
 182  * store it in *@vnode, and returns the value string.
 183  * The @key can contain several words jointed with '.'. If @parent is NULL,
 184  * this searches the node from whole tree. Return the value string if a
 185  * matched key found, return NULL if no node is matched.
 186  * Note that this returns 0-length string and stores NULL in *@vnode if the
 187  * key has no value. And also it will return the value of the first entry if
 188  * the value is an array.
 189  */
 190 const char * __init
 191 xbc_node_find_value(struct xbc_node *parent, const char *key,
 192                     struct xbc_node **vnode)
 193 {
 194         struct xbc_node *node = xbc_node_find_child(parent, key);
 195
 196         if (!node || !xbc_node_is_key(node))
 197                 return NULL;
 198
 199         node = xbc_node_get_child(node);
 200         if (node && !xbc_node_is_value(node))
 201                 return NULL;
 202
 203         if (vnode)
 204                 *vnode = node;
 205
 206         return node ? xbc_node_get_data(node) : "";
 207 }
 208
 209 /**
 210  * xbc_node_compose_key_after() - Compose partial key string of the XBC node
 211  * @root: Root XBC node
 212  * @node: Target XBC node.
 213  * @buf: A buffer to store the key.
 214  * @size: The size of the @buf.
 215  *
 216  * Compose the partial key of the @node into @buf, which is starting right
 217  * after @root (@root is not included.) If @root is NULL, this returns full
 218  * key words of @node.
 219  * Returns the total length of the key stored in @buf. Returns -EINVAL
 220  * if @node is NULL or @root is not the ancestor of @node or @root is @node,
 221  * or returns -ERANGE if the key depth is deeper than max depth.
 222  * This is expected to be used with xbc_find_node() to list up all (child)
 223  * keys under given key.
 224  */
 225 int __init xbc_node_compose_key_after(struct xbc_node *root,
 226                                       struct xbc_node *node,
 227                                       char *buf, size_t size)
 228 {
 229         u16 keys[XBC_DEPTH_MAX];
 230         int depth = 0, ret = 0, total = 0;
 231
 232         if (!node || node == root)
 233                 return -EINVAL;
 234
 235         if (xbc_node_is_value(node))
 236                 node = xbc_node_get_parent(node);
 237
 238         while (node && node != root) {
 239                 keys[depth++] = xbc_node_index(node);
 240                 if (depth == XBC_DEPTH_MAX)
 241                         return -ERANGE;
 242                 node = xbc_node_get_parent(node);
 243         }
 244         if (!node && root)
 245                 return -EINVAL;
 246
 247         while (--depth >= 0) {
 248                 node = xbc_nodes + keys[depth];
 249                 ret = snprintf(buf, size, "%s%s", xbc_node_get_data(node),
 250                                depth ? "." : "");
 251                 if (ret < 0)
 252                         return ret;
 253                 if (ret > size) {
 254                         size = 0;
 255                 } else {
 256                         size -= ret;
 257                         buf += ret;
 258                 }
 259                 total += ret;
 260         }
 261
 262         return total;
 263 }
 264
 265 /**
 266  * xbc_node_find_next_leaf() - Find the next leaf node under given node
 267  * @root: An XBC root node
 268  * @node: An XBC node which starts from.
 269  *
 270  * Search the next leaf node (which means the terminal key node) of @node
 271  * under @root node (including @root node itself).
 272  * Return the next node or NULL if next leaf node is not found.
 273  */
 274 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
 275                                                  struct xbc_node *node)
 276 {
 277         if (unlikely(!xbc_data))
 278                 return NULL;
 279
 280         if (!node) {    /* First try */
 281                 node = root;
 282                 if (!node)
 283                         node = xbc_nodes;
 284         } else {
 285                 if (node == root)       /* @root was a leaf, no child node. */
 286                         return NULL;
 287
 288                 while (!node->next) {
 289                         node = xbc_node_get_parent(node);
 290                         if (node == root)
 291                                 return NULL;
 292                         /* User passed a node which is not uder parent */
 293                         if (WARN_ON(!node))
 294                                 return NULL;
 295                 }
 296                 node = xbc_node_get_next(node);
 297         }
 298
 299         while (node && !xbc_node_is_leaf(node))
 300                 node = xbc_node_get_child(node);
 301
 302         return node;
 303 }
 304
 305 /**
 306  * xbc_node_find_next_key_value() - Find the next key-value pair nodes
 307  * @root: An XBC root node
 308  * @leaf: A container pointer of XBC node which starts from.
 309  *
 310  * Search the next leaf node (which means the terminal key node) of *@leaf
 311  * under @root node. Returns the value and update *@leaf if next leaf node
 312  * is found, or NULL if no next leaf node is found.
 313  * Note that this returns 0-length string if the key has no value, or
 314  * the value of the first entry if the value is an array.
 315  */
 316 const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
 317                                                  struct xbc_node **leaf)
 318 {
 319         /* tip must be passed */
 320         if (WARN_ON(!leaf))
 321                 return NULL;
 322
 323         *leaf = xbc_node_find_next_leaf(root, *leaf);
 324         if (!*leaf)
 325                 return NULL;
 326         if ((*leaf)->child)
 327                 return xbc_node_get_data(xbc_node_get_child(*leaf));
 328         else
 329                 return "";      /* No value key */
 330 }
 331
 332 /* XBC parse and tree build */
 333
 334 static int __init xbc_init_node(struct xbc_node *node, char *data, u32 flag)
 335 {
 336         unsigned long offset = data - xbc_data;
 337
 338         if (WARN_ON(offset >= XBC_DATA_MAX))
 339                 return -EINVAL;
 340
 341         node->data = (u16)offset | flag;
 342         node->child = 0;
 343         node->next = 0;
 344
 345         return 0;
 346 }
 347
 348 static struct xbc_node * __init xbc_add_node(char *data, u32 flag)
 349 {
 350         struct xbc_node *node;
 351
 352         if (xbc_node_num == XBC_NODE_MAX)
 353                 return NULL;
 354
 355         node = &xbc_nodes[xbc_node_num++];
 356         if (xbc_init_node(node, data, flag) < 0)
 357                 return NULL;
 358
 359         return node;
 360 }
 361
 362 static inline __init struct xbc_node *xbc_last_sibling(struct xbc_node *node)
 363 {
 364         while (node->next)
 365                 node = xbc_node_get_next(node);
 366
 367         return node;
 368 }
 369
 370 static struct xbc_node * __init xbc_add_sibling(char *data, u32 flag)
 371 {
 372         struct xbc_node *sib, *node = xbc_add_node(data, flag);
 373
 374         if (node) {
 375                 if (!last_parent) {
 376                         node->parent = XBC_NODE_MAX;
 377                         sib = xbc_last_sibling(xbc_nodes);
 378                         sib->next = xbc_node_index(node);
 379                 } else {
 380                         node->parent = xbc_node_index(last_parent);
 381                         if (!last_parent->child) {
 382                                 last_parent->child = xbc_node_index(node);
 383                         } else {
 384                                 sib = xbc_node_get_child(last_parent);
 385                                 sib = xbc_last_sibling(sib);
 386                                 sib->next = xbc_node_index(node);
 387                         }
 388                 }
 389         } else
 390                 xbc_parse_error("Too many nodes", data);
 391
 392         return node;
 393 }
 394
 395 static inline __init struct xbc_node *xbc_add_child(char *data, u32 flag)
 396 {
 397         struct xbc_node *node = xbc_add_sibling(data, flag);
 398
 399         if (node)
 400                 last_parent = node;
 401
 402         return node;
 403 }
 404
 405 static inline __init bool xbc_valid_keyword(char *key)
 406 {
 407         if (key[0] == '\0')
 408                 return false;
 409
 410         while (isalnum(*key) || *key == '-' || *key == '_')
 411                 key++;
 412
 413         return *key == '\0';
 414 }
 415
 416 static char *skip_comment(char *p)
 417 {
 418         char *ret;
 419
 420         ret = strchr(p, '\n');
 421         if (!ret)
 422                 ret = p + strlen(p);
 423         else
 424                 ret++;
 425
 426         return ret;
 427 }
 428
 429 static char *skip_spaces_until_newline(char *p)
 430 {
 431         while (isspace(*p) && *p != '\n')
 432                 p++;
 433         return p;
 434 }
 435
 436 static int __init __xbc_open_brace(char *p)
 437 {
 438         /* Push the last key as open brace */
 439         open_brace[brace_index++] = xbc_node_index(last_parent);
 440         if (brace_index >= XBC_DEPTH_MAX)
 441                 return xbc_parse_error("Exceed max depth of braces", p);
 442
 443         return 0;
 444 }
 445
 446 static int __init __xbc_close_brace(char *p)
 447 {
 448         brace_index--;
 449         if (!last_parent || brace_index < 0 ||
 450             (open_brace[brace_index] != xbc_node_index(last_parent)))
 451                 return xbc_parse_error("Unexpected closing brace", p);
 452
 453         if (brace_index == 0)
 454                 last_parent = NULL;
 455         else
 456                 last_parent = &xbc_nodes[open_brace[brace_index - 1]];
 457
 458         return 0;
 459 }
 460
 461 /*
 462  * Return delimiter or error, no node added. As same as lib/cmdline.c,
 463  * you can use " around spaces, but can't escape " for value.
 464  */
 465 static int __init __xbc_parse_value(char **__v, char **__n)
 466 {
 467         char *p, *v = *__v;
 468         int c, quotes = 0;
 469
 470         v = skip_spaces(v);
 471         while (*v == '#') {
 472                 v = skip_comment(v);
 473                 v = skip_spaces(v);
 474         }
 475         if (*v == '"' || *v == '\'') {
 476                 quotes = *v;
 477                 v++;
 478         }
 479         p = v - 1;
 480         while ((c = *++p)) {
 481                 if (!isprint(c) && !isspace(c))
 482                         return xbc_parse_error("Non printable value", p);
 483                 if (quotes) {
 484                         if (c != quotes)
 485                                 continue;
 486                         quotes = 0;
 487                         *p++ = '\0';
 488                         p = skip_spaces_until_newline(p);
 489                         c = *p;
 490                         if (c && !strchr(",;\n#}", c))
 491                                 return xbc_parse_error("No value delimiter", p);
 492                         if (*p)
 493                                 p++;
 494                         break;
 495                 }
 496                 if (strchr(",;\n#}", c)) {
 497                         *p++ = '\0';
 498                         v = strim(v);
 499                         break;
 500                 }
 501         }
 502         if (quotes)
 503                 return xbc_parse_error("No closing quotes", p);
 504         if (c == '#') {
 505                 p = skip_comment(p);
 506                 c = '\n';       /* A comment must be treated as a newline */
 507         }
 508         *__n = p;
 509         *__v = v;
 510
 511         return c;
 512 }
 513
 514 static int __init xbc_parse_array(char **__v)
 515 {
 516         struct xbc_node *node;
 517         char *next;
 518         int c = 0;
 519
 520         do {
 521                 c = __xbc_parse_value(__v, &next);
 522                 if (c < 0)
 523                         return c;
 524
 525                 node = xbc_add_sibling(*__v, XBC_VALUE);
 526                 if (!node)
 527                         return -ENOMEM;
 528                 *__v = next;
 529         } while (c == ',');
 530         node->next = 0;
 531
 532         return c;
 533 }
 534
 535 static inline __init
 536 struct xbc_node *find_match_node(struct xbc_node *node, char *k)
 537 {
 538         while (node) {
 539                 if (!strcmp(xbc_node_get_data(node), k))
 540                         break;
 541                 node = xbc_node_get_next(node);
 542         }
 543         return node;
 544 }
 545
 546 static int __init __xbc_add_key(char *k)
 547 {
 548         struct xbc_node *node, *child;
 549
 550         if (!xbc_valid_keyword(k))
 551                 return xbc_parse_error("Invalid keyword", k);
 552
 553         if (unlikely(xbc_node_num == 0))
 554                 goto add_node;
 555
 556         if (!last_parent)       /* the first level */
 557                 node = find_match_node(xbc_nodes, k);
 558         else {
 559                 child = xbc_node_get_child(last_parent);
 560                 if (child && xbc_node_is_value(child))
 561                         return xbc_parse_error("Subkey is mixed with value", k);
 562                 node = find_match_node(child, k);
 563         }
 564
 565         if (node)
 566                 last_parent = node;
 567         else {
 568 add_node:
 569                 node = xbc_add_child(k, XBC_KEY);
 570                 if (!node)
 571                         return -ENOMEM;
 572         }
 573         return 0;
 574 }
 575
 576 static int __init __xbc_parse_keys(char *k)
 577 {
 578         char *p;
 579         int ret;
 580
 581         k = strim(k);
 582         while ((p = strchr(k, '.'))) {
 583                 *p++ = '\0';
 584                 ret = __xbc_add_key(k);
 585                 if (ret)
 586                         return ret;
 587                 k = p;
 588         }
 589
 590         return __xbc_add_key(k);
 591 }
 592
 593 static int __init xbc_parse_kv(char **k, char *v, int op)
 594 {
 595         struct xbc_node *prev_parent = last_parent;
 596         struct xbc_node *child;
 597         char *next;
 598         int c, ret;
 599
 600         ret = __xbc_parse_keys(*k);
 601         if (ret)
 602                 return ret;
 603
 604         child = xbc_node_get_child(last_parent);
 605         if (child) {
 606                 if (xbc_node_is_key(child))
 607                         return xbc_parse_error("Value is mixed with subkey", v);
 608                 else if (op == '=')
 609                         return xbc_parse_error("Value is redefined", v);
 610         }
 611
 612         c = __xbc_parse_value(&v, &next);
 613         if (c < 0)
 614                 return c;
 615
 616         if (op == ':' && child) {
 617                 xbc_init_node(child, v, XBC_VALUE);
 618         } else if (!xbc_add_sibling(v, XBC_VALUE))
 619                 return -ENOMEM;
 620
 621         if (c == ',') { /* Array */
 622                 c = xbc_parse_array(&next);
 623                 if (c < 0)
 624                         return c;
 625         }
 626
 627         last_parent = prev_parent;
 628
 629         if (c == '}') {
 630                 ret = __xbc_close_brace(next - 1);
 631                 if (ret < 0)
 632                         return ret;
 633         }
 634
 635         *k = next;
 636
 637         return 0;
 638 }
 639
 640 static int __init xbc_parse_key(char **k, char *n)
 641 {
 642         struct xbc_node *prev_parent = last_parent;
 643         int ret;
 644
 645         *k = strim(*k);
 646         if (**k != '\0') {
 647                 ret = __xbc_parse_keys(*k);
 648                 if (ret)
 649                         return ret;
 650                 last_parent = prev_parent;
 651         }
 652         *k = n;
 653
 654         return 0;
 655 }
 656
 657 static int __init xbc_open_brace(char **k, char *n)
 658 {
 659         int ret;
 660
 661         ret = __xbc_parse_keys(*k);
 662         if (ret)
 663                 return ret;
 664         *k = n;
 665
 666         return __xbc_open_brace(n - 1);
 667 }
 668
 669 static int __init xbc_close_brace(char **k, char *n)
 670 {
 671         int ret;
 672
 673         ret = xbc_parse_key(k, n);
 674         if (ret)
 675                 return ret;
 676         /* k is updated in xbc_parse_key() */
 677
 678         return __xbc_close_brace(n - 1);
 679 }
 680
 681 static int __init xbc_verify_tree(void)
 682 {
 683         int i, depth, len, wlen;
 684         struct xbc_node *n, *m;
 685
 686         /* Brace closing */
 687         if (brace_index) {
 688                 n = &xbc_nodes[open_brace[brace_index]];
 689                 return xbc_parse_error("Brace is not closed",
 690                                         xbc_node_get_data(n));
 691         }
 692
 693         /* Empty tree */
 694         if (xbc_node_num == 0) {
 695                 xbc_parse_error("Empty config", xbc_data);
 696                 return -ENOENT;
 697         }
 698
 699         for (i = 0; i < xbc_node_num; i++) {
 700                 if (xbc_nodes[i].next > xbc_node_num) {
 701                         return xbc_parse_error("No closing brace",
 702                                 xbc_node_get_data(xbc_nodes + i));
 703                 }
 704         }
 705
 706         /* Key tree limitation check */
 707         n = &xbc_nodes[0];
 708         depth = 1;
 709         len = 0;
 710
 711         while (n) {
 712                 wlen = strlen(xbc_node_get_data(n)) + 1;
 713                 len += wlen;
 714                 if (len > XBC_KEYLEN_MAX)
 715                         return xbc_parse_error("Too long key length",
 716                                 xbc_node_get_data(n));
 717
 718                 m = xbc_node_get_child(n);
 719                 if (m && xbc_node_is_key(m)) {
 720                         n = m;
 721                         depth++;
 722                         if (depth > XBC_DEPTH_MAX)
 723                                 return xbc_parse_error("Too many key words",
 724                                                 xbc_node_get_data(n));
 725                         continue;
 726                 }
 727                 len -= wlen;
 728                 m = xbc_node_get_next(n);
 729                 while (!m) {
 730                         n = xbc_node_get_parent(n);
 731                         if (!n)
 732                                 break;
 733                         len -= strlen(xbc_node_get_data(n)) + 1;
 734                         depth--;
 735                         m = xbc_node_get_next(n);
 736                 }
 737                 n = m;
 738         }
 739
 740         return 0;
 741 }
 742
 743 /**
 744  * xbc_destroy_all() - Clean up all parsed bootconfig
 745  *
 746  * This clears all data structures of parsed bootconfig on memory.
 747  * If you need to reuse xbc_init() with new boot config, you can
 748  * use this.
 749  */
 750 void __init xbc_destroy_all(void)
 751 {
 752         xbc_data = NULL;
 753         xbc_data_size = 0;
 754         xbc_node_num = 0;
 755         memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
 756         xbc_nodes = NULL;
 757         brace_index = 0;
 758 }
 759
 760 /**
 761  * xbc_init() - Parse given XBC file and build XBC internal tree
 762  * @buf: boot config text
 763  * @emsg: A pointer of const char * to store the error message
 764  * @epos: A pointer of int to store the error position
 765  *
 766  * This parses the boot config text in @buf. @buf must be a
 767  * null terminated string and smaller than XBC_DATA_MAX.
 768  * Return the number of stored nodes (>0) if succeeded, or -errno
 769  * if there is any error.
 770  * In error cases, @emsg will be updated with an error message and
 771  * @epos will be updated with the error position which is the byte offset
 772  * of @buf. If the error is not a parser error, @epos will be -1.
 773  */
 774 int __init xbc_init(char *buf, const char **emsg, int *epos)
 775 {
 776         char *p, *q;
 777         int ret, c;
 778
 779         if (epos)
 780                 *epos = -1;
 781
 782         if (xbc_data) {
 783                 if (emsg)
 784                         *emsg = "Bootconfig is already initialized";
 785                 return -EBUSY;
 786         }
 787
 788         ret = strlen(buf);
 789         if (ret > XBC_DATA_MAX - 1 || ret == 0) {
 790                 if (emsg)
 791                         *emsg = ret ? "Config data is too big" :
 792                                 "Config data is empty";
 793                 return -ERANGE;
 794         }
 795
 796         xbc_nodes = memblock_alloc(sizeof(struct xbc_node) * XBC_NODE_MAX,
 797                                    SMP_CACHE_BYTES);
 798         if (!xbc_nodes) {
 799                 if (emsg)
 800                         *emsg = "Failed to allocate bootconfig nodes";
 801                 return -ENOMEM;
 802         }
 803         memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX);
 804         xbc_data = buf;
 805         xbc_data_size = ret + 1;
 806         last_parent = NULL;
 807
 808         p = buf;
 809         do {
 810                 q = strpbrk(p, "{}=+;:\n#");
 811                 if (!q) {
 812                         p = skip_spaces(p);
 813                         if (*p != '\0')
 814                                 ret = xbc_parse_error("No delimiter", p);
 815                         break;
 816                 }
 817
 818                 c = *q;
 819                 *q++ = '\0';
 820                 switch (c) {
 821                 case ':':
 822                 case '+':
 823                         if (*q++ != '=') {
 824                                 ret = xbc_parse_error(c == '+' ?
 825                                                 "Wrong '+' operator" :
 826                                                 "Wrong ':' operator",
 827                                                         q - 2);
 828                                 break;
 829                         }
 830                         fallthrough;
 831                 case '=':
 832                         ret = xbc_parse_kv(&p, q, c);
 833                         break;
 834                 case '{':
 835                         ret = xbc_open_brace(&p, q);
 836                         break;
 837                 case '#':
 838                         q = skip_comment(q);
 839                         fallthrough;
 840                 case ';':
 841                 case '\n':
 842                         ret = xbc_parse_key(&p, q);
 843                         break;
 844                 case '}':
 845                         ret = xbc_close_brace(&p, q);
 846                         break;
 847                 }
 848         } while (!ret);
 849
 850         if (!ret)
 851                 ret = xbc_verify_tree();
 852
 853         if (ret < 0) {
 854                 if (epos)
 855                         *epos = xbc_err_pos;
 856                 if (emsg)
 857                         *emsg = xbc_err_msg;
 858                 xbc_destroy_all();
 859         } else
 860                 ret = xbc_node_num;
 861
 862         return ret;
 863 }
 864
 865 /**
 866  * xbc_debug_dump() - Dump current XBC node list
 867  *
 868  * Dump the current XBC node list on printk buffer for debug.
 869  */
 870 void __init xbc_debug_dump(void)
 871 {
 872         int i;
 873
 874         for (i = 0; i < xbc_node_num; i++) {
 875                 pr_debug("[%d] %s (%s) .next=%d, .child=%d .parent=%d\n", i,
 876                         xbc_node_get_data(xbc_nodes + i),
 877                         xbc_node_is_value(xbc_nodes + i) ? "value" : "key",
 878                         xbc_nodes[i].next, xbc_nodes[i].child,
 879                         xbc_nodes[i].parent);
 880         }
 881 }