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