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