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