git.ozlabs.org Git - ccan/blob - ccan/tal/tal.c

   1 /* Licensed under BSD-MIT - see LICENSE file for details */
   2 #include <ccan/tal/tal.h>
   3 #include <ccan/compiler/compiler.h>
   4 #include <ccan/list/list.h>
   5 #include <ccan/alignof/alignof.h>
   6 #include <assert.h>
   7 #include <stdio.h>
   8 #include <stddef.h>
   9 #include <string.h>
  10 #include <limits.h>
  11 #include <stdint.h>
  12 #include <errno.h>
  13
  14 //#define TAL_DEBUG 1
  15
  16 #define NOTIFY_IS_DESTRUCTOR 512
  17 #define NOTIFY_EXTRA_ARG 1024
  18
  19 /* This makes our parent_child ptr stand out for to_tal_hdr checks */
  20 #define TAL_PTR_OBFUSTICATOR ((intptr_t)0x1984200820142016ULL)
  21
  22 /* 32-bit type field, first byte 0 in either endianness. */
  23 enum prop_type {
  24         CHILDREN = 0x00c1d500,
  25         NAME = 0x00111100,
  26         NOTIFIER = 0x00071f00,
  27         LENGTH = 0x00515300
  28 };
  29
  30 struct tal_hdr {
  31         struct list_node list;
  32         struct prop_hdr *prop;
  33         /* XOR with TAL_PTR_OBFUSTICATOR */
  34         intptr_t parent_child;
  35 };
  36
  37 struct prop_hdr {
  38         enum prop_type type;
  39         struct prop_hdr *next;
  40 };
  41
  42 struct children {
  43         struct prop_hdr hdr; /* CHILDREN */
  44         struct tal_hdr *parent;
  45         struct list_head children; /* Head of siblings. */
  46 };
  47
  48 struct name {
  49         struct prop_hdr hdr; /* NAME */
  50         char name[];
  51 };
  52
  53 struct length {
  54         struct prop_hdr hdr; /* LENGTH */
  55         size_t len;
  56 };
  57
  58 struct notifier {
  59         struct prop_hdr hdr; /* NOTIFIER */
  60         enum tal_notify_type types;
  61         union {
  62                 void (*notifyfn)(tal_t *, enum tal_notify_type, void *);
  63                 void (*destroy)(tal_t *); /* If NOTIFY_IS_DESTRUCTOR set */
  64                 void (*destroy2)(tal_t *, void *); /* If NOTIFY_EXTRA_ARG */
  65         } u;
  66 };
  67
  68 /* Extra arg */
  69 struct notifier_extra_arg {
  70         struct notifier n;
  71         void *arg;
  72 };
  73
  74 #define EXTRA_ARG(n) (((struct notifier_extra_arg *)(n))->arg)
  75
  76 static struct {
  77         struct tal_hdr hdr;
  78         struct children c;
  79 } null_parent = { { { &null_parent.hdr.list, &null_parent.hdr.list },
  80                     &null_parent.c.hdr, TAL_PTR_OBFUSTICATOR },
  81                   { { CHILDREN, NULL },
  82                     &null_parent.hdr,
  83                     { { &null_parent.c.children.n,
  84                         &null_parent.c.children.n } }
  85                   }
  86 };
  87
  88
  89 static void *(*allocfn)(size_t size) = malloc;
  90 static void *(*resizefn)(void *, size_t size) = realloc;
  91 static void (*freefn)(void *) = free;
  92 static void (*errorfn)(const char *msg) = (void *)abort;
  93 /* Count on non-destrutor notifiers; often stays zero. */
  94 static size_t notifiers = 0;
  95
  96 static inline void COLD call_error(const char *msg)
  97 {
  98         errorfn(msg);
  99 }
 100
 101 static bool get_destroying_bit(intptr_t parent_child)
 102 {
 103         return parent_child & 1;
 104 }
 105
 106 static void set_destroying_bit(intptr_t *parent_child)
 107 {
 108         *parent_child |= 1;
 109 }
 110
 111 static struct children *ignore_destroying_bit(intptr_t parent_child)
 112 {
 113         return (void *)((parent_child ^ TAL_PTR_OBFUSTICATOR) & ~(intptr_t)1);
 114 }
 115
 116 /* This means valgrind can see leaks. */
 117 void tal_cleanup(void)
 118 {
 119         struct tal_hdr *i;
 120
 121         while ((i = list_top(&null_parent.c.children, struct tal_hdr, list))) {
 122                 list_del(&i->list);
 123                 memset(i, 0, sizeof(*i));
 124         }
 125
 126         /* Cleanup any taken pointers. */
 127         take_cleanup();
 128 }
 129
 130 /* We carefully start all real properties with a zero byte. */
 131 static bool is_literal(const struct prop_hdr *prop)
 132 {
 133         return ((char *)prop)[0] != 0;
 134 }
 135
 136 #ifndef NDEBUG
 137 static const void *bounds_start, *bounds_end;
 138
 139 static void update_bounds(const void *new, size_t size)
 140 {
 141         if (unlikely(!bounds_start)) {
 142                 bounds_start = new;
 143                 bounds_end = (char *)new + size;
 144         } else if (new < bounds_start)
 145                 bounds_start = new;
 146         else if ((char *)new + size > (char *)bounds_end)
 147                 bounds_end = (char *)new + size;
 148 }
 149
 150 static bool in_bounds(const void *p)
 151 {
 152         return !p
 153                 || (p >= (void *)&null_parent && p <= (void *)(&null_parent + 1))
 154                 || (p >= bounds_start && p <= bounds_end);
 155 }
 156 #else
 157 static void update_bounds(const void *new, size_t size)
 158 {
 159 }
 160
 161 static bool in_bounds(const void *p)
 162 {
 163         return true;
 164 }
 165 #endif
 166
 167 static void check_bounds(const void *p)
 168 {
 169         if (!in_bounds(p))
 170                 call_error("Not a valid header");
 171 }
 172
 173 static struct tal_hdr *to_tal_hdr(const void *ctx)
 174 {
 175         struct tal_hdr *t;
 176
 177         t = (struct tal_hdr *)((char *)ctx - sizeof(struct tal_hdr));
 178         check_bounds(t);
 179         check_bounds(ignore_destroying_bit(t->parent_child));
 180         check_bounds(t->list.next);
 181         check_bounds(t->list.prev);
 182         if (t->prop && !is_literal(t->prop))
 183                 check_bounds(t->prop);
 184         return t;
 185 }
 186
 187 static struct tal_hdr *to_tal_hdr_or_null(const void *ctx)
 188 {
 189         if (!ctx)
 190                 return &null_parent.hdr;
 191         return to_tal_hdr(ctx);
 192 }
 193
 194 static void *from_tal_hdr(const struct tal_hdr *hdr)
 195 {
 196         return (void *)(hdr + 1);
 197 }
 198
 199 #ifdef TAL_DEBUG
 200 static void *from_tal_hdr_or_null(struct tal_hdr *hdr)
 201 {
 202         if (hdr == &null_parent.hdr)
 203                 return NULL;
 204         return from_tal_hdr(hdr);
 205 }
 206
 207 static struct tal_hdr *debug_tal(struct tal_hdr *tal)
 208 {
 209         tal_check(from_tal_hdr_or_null(tal), "TAL_DEBUG ");
 210         return tal;
 211 }
 212 #else
 213 static struct tal_hdr *debug_tal(struct tal_hdr *tal)
 214 {
 215         return tal;
 216 }
 217 #endif
 218
 219 static void notify(const struct tal_hdr *ctx,
 220                    enum tal_notify_type type, const void *info,
 221                    int saved_errno)
 222 {
 223         const struct prop_hdr *p;
 224
 225         for (p = ctx->prop; p; p = p->next) {
 226                 struct notifier *n;
 227
 228                 if (is_literal(p))
 229                         break;
 230                 if (p->type != NOTIFIER)
 231                         continue;
 232                 n = (struct notifier *)p;
 233                 if (n->types & type) {
 234                         errno = saved_errno;
 235                         if (n->types & NOTIFY_IS_DESTRUCTOR) {
 236                                 if (n->types & NOTIFY_EXTRA_ARG)
 237                                         n->u.destroy2(from_tal_hdr(ctx),
 238                                                       EXTRA_ARG(n));
 239                                 else
 240                                         n->u.destroy(from_tal_hdr(ctx));
 241                         } else
 242                                 n->u.notifyfn(from_tal_hdr(ctx), type,
 243                                               (void *)info);
 244                 }
 245         }
 246 }
 247
 248 static void *allocate(size_t size)
 249 {
 250         void *ret = allocfn(size);
 251         if (!ret)
 252                 call_error("allocation failed");
 253         else
 254                 update_bounds(ret, size);
 255         return ret;
 256 }
 257
 258 static struct prop_hdr **find_property_ptr(const struct tal_hdr *t,
 259                                            enum prop_type type)
 260 {
 261         struct prop_hdr **p;
 262
 263         for (p = (struct prop_hdr **)&t->prop; *p; p = &(*p)->next) {
 264                 if (is_literal(*p)) {
 265                         if (type == NAME)
 266                                 return p;
 267                         break;
 268                 }
 269                 if ((*p)->type == type)
 270                         return p;
 271         }
 272         return NULL;
 273 }
 274
 275 static void *find_property(const struct tal_hdr *parent, enum prop_type type)
 276 {
 277         struct prop_hdr **p = find_property_ptr(parent, type);
 278
 279         if (p)
 280                 return *p;
 281         return NULL;
 282 }
 283
 284 static void init_property(struct prop_hdr *hdr,
 285                           struct tal_hdr *parent,
 286                           enum prop_type type)
 287 {
 288         hdr->type = type;
 289         hdr->next = parent->prop;
 290         parent->prop = hdr;
 291 }
 292
 293 static struct notifier *add_notifier_property(struct tal_hdr *t,
 294                                               enum tal_notify_type types,
 295                                               void (*fn)(void *,
 296                                                          enum tal_notify_type,
 297                                                          void *),
 298                                               void *extra_arg)
 299 {
 300         struct notifier *prop;
 301
 302         if (types & NOTIFY_EXTRA_ARG)
 303                 prop = allocate(sizeof(struct notifier_extra_arg));
 304         else
 305                 prop = allocate(sizeof(struct notifier));
 306
 307         if (prop) {
 308                 init_property(&prop->hdr, t, NOTIFIER);
 309                 prop->types = types;
 310                 prop->u.notifyfn = fn;
 311                 if (types & NOTIFY_EXTRA_ARG)
 312                         EXTRA_ARG(prop) = extra_arg;
 313         }
 314         return prop;
 315 }
 316
 317 static enum tal_notify_type del_notifier_property(struct tal_hdr *t,
 318                                                   void (*fn)(tal_t *,
 319                                                              enum tal_notify_type,
 320                                                              void *),
 321                                                   bool match_extra_arg,
 322                                                   void *extra_arg)
 323 {
 324         struct prop_hdr **p;
 325
 326         for (p = (struct prop_hdr **)&t->prop; *p; p = &(*p)->next) {
 327                 struct notifier *n;
 328                 enum tal_notify_type types;
 329
 330                 if (is_literal(*p))
 331                         break;
 332                 if ((*p)->type != NOTIFIER)
 333                         continue;
 334                 n = (struct notifier *)*p;
 335                 if (n->u.notifyfn != fn)
 336                         continue;
 337
 338                 types = n->types;
 339                 if ((types & NOTIFY_EXTRA_ARG)
 340                     && match_extra_arg
 341                     && extra_arg != EXTRA_ARG(n))
 342                         continue;
 343
 344                 *p = (*p)->next;
 345                 freefn(n);
 346                 return types & ~(NOTIFY_IS_DESTRUCTOR|NOTIFY_EXTRA_ARG);
 347         }
 348         return 0;
 349 }
 350
 351 static struct name *add_name_property(struct tal_hdr *t, const char *name)
 352 {
 353         struct name *prop;
 354
 355         prop = allocate(sizeof(*prop) + strlen(name) + 1);
 356         if (prop) {
 357                 init_property(&prop->hdr, t, NAME);
 358                 strcpy(prop->name, name);
 359         }
 360         return prop;
 361 }
 362
 363 static struct children *add_child_property(struct tal_hdr *parent,
 364                                            struct tal_hdr *child UNNEEDED)
 365 {
 366         struct children *prop = allocate(sizeof(*prop));
 367         if (prop) {
 368                 init_property(&prop->hdr, parent, CHILDREN);
 369                 prop->parent = parent;
 370                 list_head_init(&prop->children);
 371         }
 372         return prop;
 373 }
 374
 375 static bool add_child(struct tal_hdr *parent, struct tal_hdr *child)
 376 {
 377         struct children *children = find_property(parent, CHILDREN);
 378
 379         if (!children) {
 380                 children = add_child_property(parent, child);
 381                 if (!children)
 382                         return false;
 383         }
 384         list_add(&children->children, &child->list);
 385         child->parent_child = (intptr_t)children ^ TAL_PTR_OBFUSTICATOR;
 386         return true;
 387 }
 388
 389 static void del_tree(struct tal_hdr *t, const tal_t *orig, int saved_errno)
 390 {
 391         struct prop_hdr **prop, *p, *next;
 392
 393         /* Already being destroyed?  Don't loop. */
 394         if (unlikely(get_destroying_bit(t->parent_child)))
 395                 return;
 396
 397         set_destroying_bit(&t->parent_child);
 398
 399         /* Call free notifiers. */
 400         notify(t, TAL_NOTIFY_FREE, (tal_t *)orig, saved_errno);
 401
 402         /* Now free children and groups. */
 403         prop = find_property_ptr(t, CHILDREN);
 404         if (prop) {
 405                 struct tal_hdr *i;
 406                 struct children *c = (struct children *)*prop;
 407
 408                 while ((i = list_top(&c->children, struct tal_hdr, list))) {
 409                         list_del(&i->list);
 410                         del_tree(i, orig, saved_errno);
 411                 }
 412         }
 413
 414         /* Finally free our properties. */
 415         for (p = t->prop; p && !is_literal(p); p = next) {
 416                 next = p->next;
 417                 /* LENGTH is appended, so don't free separately! */
 418                 if (p->type != LENGTH)
 419                         freefn(p);
 420         }
 421         freefn(t);
 422 }
 423
 424 static size_t extra_for_length(size_t size)
 425 {
 426         size_t extra;
 427         const size_t align = ALIGNOF(struct length);
 428
 429         /* Round up size, and add tailer. */
 430         extra = ((size + align-1) & ~(align-1)) - size;
 431         extra += sizeof(struct length);
 432         return extra;
 433 }
 434
 435 void *tal_alloc_(const tal_t *ctx, size_t size,
 436                  bool clear, bool add_length, const char *label)
 437 {
 438         size_t req_size = size;
 439         struct tal_hdr *child, *parent = debug_tal(to_tal_hdr_or_null(ctx));
 440
 441 #ifdef CCAN_TAL_DEBUG
 442         /* Always record length if debugging. */
 443         add_length = true;
 444 #endif
 445         if (add_length)
 446                 size += extra_for_length(size);
 447
 448         child = allocate(sizeof(struct tal_hdr) + size);
 449         if (!child)
 450                 return NULL;
 451         if (clear)
 452                 memset(from_tal_hdr(child), 0, req_size);
 453         child->prop = (void *)label;
 454
 455         if (add_length) {
 456                 struct length *lprop;
 457                 lprop = (struct length *)((char *)(child+1) + size) - 1;
 458                 init_property(&lprop->hdr, child, LENGTH);
 459                 lprop->len = req_size;
 460         }
 461         if (!add_child(parent, child)) {
 462                 freefn(child);
 463                 return NULL;
 464         }
 465         debug_tal(parent);
 466         if (notifiers)
 467                 notify(parent, TAL_NOTIFY_ADD_CHILD, from_tal_hdr(child), 0);
 468         return from_tal_hdr(debug_tal(child));
 469 }
 470
 471 static bool adjust_size(size_t *size, size_t count)
 472 {
 473         const size_t extra = sizeof(struct tal_hdr) + sizeof(struct length)*2;
 474
 475         /* Multiplication wrap */
 476         if (count && unlikely(*size * count / *size != count))
 477                 goto overflow;
 478
 479         *size *= count;
 480
 481         /* Make sure we don't wrap adding header/tailer. */
 482         if (*size + extra < extra)
 483                 goto overflow;
 484         return true;
 485 overflow:
 486         call_error("allocation size overflow");
 487         return false;
 488 }
 489
 490 void *tal_alloc_arr_(const tal_t *ctx, size_t size, size_t count, bool clear,
 491                      bool add_length, const char *label)
 492 {
 493         if (!adjust_size(&size, count))
 494                 return NULL;
 495
 496         return tal_alloc_(ctx, size, clear, add_length, label);
 497 }
 498
 499 void *tal_free(const tal_t *ctx)
 500 {
 501         if (ctx) {
 502                 struct tal_hdr *t;
 503                 int saved_errno = errno;
 504                 t = debug_tal(to_tal_hdr(ctx));
 505                 if (unlikely(get_destroying_bit(t->parent_child)))
 506                         return NULL;
 507                 if (notifiers)
 508                         notify(ignore_destroying_bit(t->parent_child)->parent,
 509                                TAL_NOTIFY_DEL_CHILD, ctx, saved_errno);
 510                 list_del(&t->list);
 511                 del_tree(t, ctx, saved_errno);
 512                 errno = saved_errno;
 513         }
 514         return NULL;
 515 }
 516
 517 void *tal_steal_(const tal_t *new_parent, const tal_t *ctx)
 518 {
 519         if (ctx) {
 520                 struct tal_hdr *newpar, *t, *old_parent;
 521
 522                 newpar = debug_tal(to_tal_hdr_or_null(new_parent));
 523                 t = debug_tal(to_tal_hdr(ctx));
 524
 525                 /* Unlink it from old parent. */
 526                 list_del(&t->list);
 527                 old_parent = ignore_destroying_bit(t->parent_child)->parent;
 528
 529                 if (unlikely(!add_child(newpar, t))) {
 530                         /* We can always add to old parent, becuase it has a
 531                          * children property already. */
 532                         if (!add_child(old_parent, t))
 533                                 abort();
 534                         return NULL;
 535                 }
 536                 debug_tal(newpar);
 537                 if (notifiers)
 538                         notify(t, TAL_NOTIFY_STEAL, new_parent, 0);
 539         }
 540         return (void *)ctx;
 541 }
 542
 543 bool tal_add_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 544 {
 545         tal_t *t = debug_tal(to_tal_hdr(ctx));
 546         return add_notifier_property(t, TAL_NOTIFY_FREE|NOTIFY_IS_DESTRUCTOR,
 547                                      (void *)destroy, NULL);
 548 }
 549
 550 bool tal_add_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
 551                           void *arg)
 552 {
 553         tal_t *t = debug_tal(to_tal_hdr(ctx));
 554         return add_notifier_property(t, TAL_NOTIFY_FREE|NOTIFY_IS_DESTRUCTOR
 555                                      |NOTIFY_EXTRA_ARG,
 556                                      (void *)destroy, arg);
 557 }
 558
 559 /* We could support notifiers with an extra arg, but we didn't add to API */
 560 bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
 561                        void (*callback)(tal_t *, enum tal_notify_type, void *))
 562 {
 563         tal_t *t = debug_tal(to_tal_hdr(ctx));
 564         struct notifier *n;
 565
 566         assert(types);
 567         assert((types & ~(TAL_NOTIFY_FREE | TAL_NOTIFY_STEAL | TAL_NOTIFY_MOVE
 568                           | TAL_NOTIFY_RESIZE | TAL_NOTIFY_RENAME
 569                           | TAL_NOTIFY_ADD_CHILD | TAL_NOTIFY_DEL_CHILD
 570                           | TAL_NOTIFY_ADD_NOTIFIER
 571                           | TAL_NOTIFY_DEL_NOTIFIER)) == 0);
 572
 573         /* Don't call notifier about itself: set types after! */
 574         n = add_notifier_property(t, 0, callback, NULL);
 575         if (unlikely(!n))
 576                 return false;
 577
 578         if (notifiers)
 579                 notify(t, TAL_NOTIFY_ADD_NOTIFIER, callback, 0);
 580
 581         n->types = types;
 582         if (types != TAL_NOTIFY_FREE)
 583                 notifiers++;
 584         return true;
 585 }
 586
 587 bool tal_del_notifier_(const tal_t *ctx,
 588                        void (*callback)(tal_t *, enum tal_notify_type, void *),
 589                        bool match_extra_arg, void *extra_arg)
 590 {
 591         struct tal_hdr *t = debug_tal(to_tal_hdr(ctx));
 592         enum tal_notify_type types;
 593
 594         types = del_notifier_property(t, callback, match_extra_arg, extra_arg);
 595         if (types) {
 596                 notify(t, TAL_NOTIFY_DEL_NOTIFIER, callback, 0);
 597                 if (types != TAL_NOTIFY_FREE)
 598                         notifiers--;
 599                 return true;
 600         }
 601         return false;
 602 }
 603
 604 bool tal_del_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 605 {
 606         return tal_del_notifier_(ctx, (void *)destroy, false, NULL);
 607 }
 608
 609 bool tal_del_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
 610                           void *arg)
 611 {
 612         return tal_del_notifier_(ctx, (void *)destroy, true, arg);
 613 }
 614
 615 bool tal_set_name_(tal_t *ctx, const char *name, bool literal)
 616 {
 617         struct tal_hdr *t = debug_tal(to_tal_hdr(ctx));
 618         struct prop_hdr **prop = find_property_ptr(t, NAME);
 619
 620         /* Get rid of any old name */
 621         if (prop) {
 622                 struct name *name = (struct name *)*prop;
 623                 if (is_literal(&name->hdr))
 624                         *prop = NULL;
 625                 else {
 626                         *prop = name->hdr.next;
 627                         freefn(name);
 628                 }
 629         }
 630
 631         if (literal && name[0]) {
 632                 struct prop_hdr **p;
 633
 634                 /* Append literal. */
 635                 for (p = &t->prop; *p && !is_literal(*p); p = &(*p)->next);
 636                 *p = (struct prop_hdr *)name;
 637         } else if (!add_name_property(t, name))
 638                 return false;
 639
 640         debug_tal(t);
 641         if (notifiers)
 642                 notify(t, TAL_NOTIFY_RENAME, name, 0);
 643         return true;
 644 }
 645
 646 const char *tal_name(const tal_t *t)
 647 {
 648         struct name *n;
 649
 650         n = find_property(debug_tal(to_tal_hdr(t)), NAME);
 651         if (!n)
 652                 return NULL;
 653
 654         if (is_literal(&n->hdr))
 655                 return (const char *)n;
 656         return n->name;
 657 }
 658
 659 size_t tal_bytelen(const tal_t *ptr)
 660 {
 661         struct length *l;
 662
 663         if (!ptr)
 664                 return 0;
 665
 666         l = find_property(debug_tal(to_tal_hdr(ptr)), LENGTH);
 667         if (!l)
 668                 return 0;
 669         return l->len;
 670 }
 671
 672 /* Start one past first child: make stopping natural in circ. list. */
 673 static struct tal_hdr *first_child(struct tal_hdr *parent)
 674 {
 675         struct children *child;
 676
 677         child = find_property(parent, CHILDREN);
 678         if (!child)
 679                 return NULL;
 680
 681         return list_top(&child->children, struct tal_hdr, list);
 682 }
 683
 684 tal_t *tal_first(const tal_t *root)
 685 {
 686         struct tal_hdr *c, *t = debug_tal(to_tal_hdr_or_null(root));
 687
 688         c = first_child(t);
 689         if (!c)
 690                 return NULL;
 691         return from_tal_hdr(c);
 692 }
 693
 694 tal_t *tal_next(const tal_t *prev)
 695 {
 696         struct tal_hdr *next, *prevhdr = debug_tal(to_tal_hdr(prev));
 697         struct list_head *head;
 698
 699         head = &ignore_destroying_bit(prevhdr->parent_child)->children;
 700         next = list_next(head, prevhdr, list);
 701         if (!next)
 702                 return NULL;
 703         return from_tal_hdr(next);
 704 }
 705
 706 tal_t *tal_parent(const tal_t *ctx)
 707 {
 708         struct tal_hdr *t;
 709
 710         if (!ctx)
 711                 return NULL;
 712
 713         t = debug_tal(to_tal_hdr(ctx));
 714         if (ignore_destroying_bit(t->parent_child)->parent == &null_parent.hdr)
 715                 return NULL;
 716         return from_tal_hdr(ignore_destroying_bit(t->parent_child)->parent);
 717 }
 718
 719 bool tal_resize_(tal_t **ctxp, size_t size, size_t count, bool clear)
 720 {
 721         struct tal_hdr *old_t, *t;
 722         struct children *child;
 723         struct prop_hdr **lenp;
 724         struct length len;
 725         size_t extra = 0;
 726
 727         old_t = debug_tal(to_tal_hdr(*ctxp));
 728
 729         if (!adjust_size(&size, count))
 730                 return false;
 731
 732         lenp = find_property_ptr(old_t, LENGTH);
 733         if (lenp) {
 734                 /* Copy here, in case we're shrinking! */
 735                 len = *(struct length *)*lenp;
 736                 extra = extra_for_length(size);
 737         } else /* If we don't have an old length, we can't clear! */
 738                 assert(!clear);
 739
 740         t = resizefn(old_t, sizeof(struct tal_hdr) + size + extra);
 741         if (!t) {
 742                 call_error("Reallocation failure");
 743                 return false;
 744         }
 745
 746         /* Copy length to end. */
 747         if (lenp) {
 748                 struct length *new_len;
 749
 750                 /* Clear between old end and new end. */
 751                 if (clear && size > len.len) {
 752                         char *old_end = (char *)(t + 1) + len.len;
 753                         memset(old_end, 0, size - len.len);
 754                 }
 755
 756                 new_len = (struct length *)((char *)(t + 1) + size
 757                                             + extra - sizeof(len));
 758                 len.len = size;
 759                 *new_len = len;
 760
 761                 /* Be careful replacing next ptr; could be old hdr. */
 762                 if (lenp == &old_t->prop)
 763                         t->prop = &new_len->hdr;
 764                 else
 765                         *lenp = &new_len->hdr;
 766         }
 767
 768         update_bounds(t, sizeof(struct tal_hdr) + size + extra);
 769
 770         /* If it didn't move, we're done! */
 771         if (t != old_t) {
 772                 /* Fix up linked list pointers. */
 773                 t->list.next->prev = t->list.prev->next = &t->list;
 774
 775                 /* Fix up child property's parent pointer. */
 776                 child = find_property(t, CHILDREN);
 777                 if (child) {
 778                         assert(child->parent == old_t);
 779                         child->parent = t;
 780                 }
 781                 *ctxp = from_tal_hdr(debug_tal(t));
 782                 if (notifiers)
 783                         notify(t, TAL_NOTIFY_MOVE, from_tal_hdr(old_t), 0);
 784         }
 785         if (notifiers)
 786                 notify(t, TAL_NOTIFY_RESIZE, (void *)size, 0);
 787
 788         return true;
 789 }
 790
 791 bool tal_expand_(tal_t **ctxp, const void *src, size_t size, size_t count)
 792 {
 793         struct length *l;
 794         size_t old_len;
 795         bool ret = false;
 796
 797         l = find_property(debug_tal(to_tal_hdr(*ctxp)), LENGTH);
 798         old_len = l->len;
 799
 800         /* Check for additive overflow */
 801         if (old_len + count * size < old_len) {
 802                 call_error("dup size overflow");
 803                 goto out;
 804         }
 805
 806         /* Don't point src inside thing we're expanding! */
 807         assert(src < *ctxp
 808                || (char *)src >= (char *)(*ctxp) + old_len);
 809
 810         if (!tal_resize_(ctxp, size, old_len/size + count, false))
 811                 goto out;
 812
 813         memcpy((char *)*ctxp + old_len, src, count * size);
 814         ret = true;
 815
 816 out:
 817         if (taken(src))
 818                 tal_free(src);
 819         return ret;
 820 }
 821
 822 void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
 823                size_t n, size_t extra, bool add_length,
 824                const char *label)
 825 {
 826         void *ret;
 827         size_t nbytes = size;
 828
 829         if (!adjust_size(&nbytes, n)) {
 830                 if (taken(p))
 831                         tal_free(p);
 832                 return NULL;
 833         }
 834
 835         /* Beware addition overflow! */
 836         if (n + extra < n) {
 837                 call_error("dup size overflow");
 838                 if (taken(p))
 839                         tal_free(p);
 840                 return NULL;
 841         }
 842
 843         if (taken(p)) {
 844                 if (unlikely(!p))
 845                         return NULL;
 846                 if (unlikely(!tal_resize_((void **)&p, size, n + extra, false)))
 847                         return tal_free(p);
 848                 if (unlikely(!tal_steal(ctx, p)))
 849                         return tal_free(p);
 850                 return (void *)p;
 851         }
 852
 853         ret = tal_alloc_arr_(ctx, size, n + extra, false, add_length, label);
 854         if (ret)
 855                 memcpy(ret, p, nbytes);
 856         return ret;
 857 }
 858
 859 void tal_set_backend(void *(*alloc_fn)(size_t size),
 860                      void *(*resize_fn)(void *, size_t size),
 861                      void (*free_fn)(void *),
 862                      void (*error_fn)(const char *msg))
 863 {
 864         if (alloc_fn)
 865                 allocfn = alloc_fn;
 866         if (resize_fn)
 867                 resizefn = resize_fn;
 868         if (free_fn)
 869                 freefn = free_fn;
 870         if (error_fn)
 871                 errorfn = error_fn;
 872 }
 873
 874 #ifdef CCAN_TAL_DEBUG
 875 static void dump_node(unsigned int indent, const struct tal_hdr *t)
 876 {
 877         unsigned int i;
 878         const struct prop_hdr *p;
 879
 880         for (i = 0; i < indent; i++)
 881                 printf("  ");
 882         printf("%p", t);
 883         for (p = t->prop; p; p = p->next) {
 884                 struct children *c;
 885                 struct name *n;
 886                 struct notifier *no;
 887                 struct length *l;
 888                 if (is_literal(p)) {
 889                         printf(" \"%s\"", (const char *)p);
 890                         break;
 891                 }
 892                 switch (p->type) {
 893                 case CHILDREN:
 894                         c = (struct children *)p;
 895                         printf(" CHILDREN(%p):parent=%p,children={%p,%p}\n",
 896                                p, c->parent,
 897                                c->children.n.prev, c->children.n.next);
 898                         break;
 899                 case NAME:
 900                         n = (struct name *)p;
 901                         printf(" NAME(%p):%s", p, n->name);
 902                         break;
 903                 case NOTIFIER:
 904                         no = (struct notifier *)p;
 905                         printf(" NOTIFIER(%p):fn=%p", p, no->u.notifyfn);
 906                         break;
 907                 case LENGTH:
 908                         l = (struct length *)p;
 909                         printf(" LENGTH(%p):len=%zu", p, l->len);
 910                         break;
 911                 default:
 912                         printf(" **UNKNOWN(%p):%i**", p, p->type);
 913                 }
 914         }
 915         printf("\n");
 916 }
 917
 918 static void tal_dump_(unsigned int level, const struct tal_hdr *t)
 919 {
 920         struct children *children;
 921
 922         dump_node(level, t);
 923
 924         children = find_property(t, CHILDREN);
 925         if (children) {
 926                 struct tal_hdr *i;
 927
 928                 list_for_each(&children->children, i, list)
 929                         tal_dump_(level + 1, i);
 930         }
 931 }
 932
 933 void tal_dump(void)
 934 {
 935         tal_dump_(0, &null_parent.hdr);
 936 }
 937 #endif /* CCAN_TAL_DEBUG */
 938
 939 #ifndef NDEBUG
 940 static bool check_err(struct tal_hdr *t, const char *errorstr,
 941                       const char *errmsg)
 942 {
 943         if (errorstr) {
 944                 /* Try not to malloc: it may be corrupted. */
 945                 char msg[strlen(errorstr) + 20 + strlen(errmsg) + 1];
 946                 sprintf(msg, "%s:%p %s", errorstr, from_tal_hdr(t), errmsg);
 947                 call_error(msg);
 948         }
 949         return false;
 950 }
 951
 952 static bool check_node(struct children *parent_child,
 953                        struct tal_hdr *t, const char *errorstr)
 954 {
 955         struct prop_hdr *p;
 956         struct name *name = NULL;
 957         struct children *children = NULL;
 958         struct length *length = NULL;
 959
 960         if (!in_bounds(t))
 961                 return check_err(t, errorstr, "invalid pointer");
 962
 963         if (ignore_destroying_bit(t->parent_child) != parent_child)
 964                 return check_err(t, errorstr, "incorrect parent");
 965
 966         for (p = t->prop; p; p = p->next) {
 967                 if (is_literal(p)) {
 968                         if (name)
 969                                 return check_err(t, errorstr,
 970                                                  "has extra literal");
 971                         break;
 972                 }
 973                 if (!in_bounds(p))
 974                         return check_err(t, errorstr,
 975                                          "has bad property pointer");
 976
 977                 switch (p->type) {
 978                 case CHILDREN:
 979                         if (children)
 980                                 return check_err(t, errorstr,
 981                                                  "has two child nodes");
 982                         children = (struct children *)p;
 983                         break;
 984                 case LENGTH:
 985                         if (length)
 986                                 return check_err(t, errorstr,
 987                                                  "has two lengths");
 988                         length = (struct length *)p;
 989                         break;
 990                 case NOTIFIER:
 991                         break;
 992                 case NAME:
 993                         if (name)
 994                                 return check_err(t, errorstr,
 995                                                  "has two names");
 996                         name = (struct name *)p;
 997                         break;
 998                 default:
 999                         return check_err(t, errorstr, "has unknown property");
1000                 }
1001         }
1002         if (children) {
1003                 struct tal_hdr *i;
1004
1005                 if (!list_check(&children->children, errorstr))
1006                         return false;
1007                 list_for_each(&children->children, i, list) {
1008                         if (!check_node(children, i, errorstr))
1009                                 return false;
1010                 }
1011         }
1012         return true;
1013 }
1014
1015 bool tal_check(const tal_t *ctx, const char *errorstr)
1016 {
1017         struct tal_hdr *t = to_tal_hdr_or_null(ctx);
1018
1019         return check_node(ignore_destroying_bit(t->parent_child), t, errorstr);
1020 }
1021 #else /* NDEBUG */
1022 bool tal_check(const tal_t *ctx, const char *errorstr)
1023 {
1024         return true;
1025 }
1026 #endif