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 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         } 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                    int saved_errno)
 208 {
 209         const struct prop_hdr *p;
 210
 211         for (p = ctx->prop; p; p = p->next) {
 212                 struct notifier *n;
 213
 214                 if (is_literal(p))
 215                         break;
 216                 if (p->type != NOTIFIER)
 217                         continue;
 218                 n = (struct notifier *)p;
 219                 if (n->types & type) {
 220                         errno = saved_errno;
 221                         if (n->types & NOTIFY_IS_DESTRUCTOR)
 222                                 n->u.destroy(from_tal_hdr(ctx));
 223                         else
 224                                 n->u.notifyfn(from_tal_hdr(ctx), type,
 225                                               (void *)info);
 226                 }
 227         }
 228 }
 229
 230 static void *allocate(size_t size)
 231 {
 232         void *ret = allocfn(size);
 233         if (!ret)
 234                 call_error("allocation failed");
 235         else
 236                 update_bounds(ret, size);
 237         return ret;
 238 }
 239
 240 static struct prop_hdr **find_property_ptr(const struct tal_hdr *t,
 241                                            enum prop_type type)
 242 {
 243         struct prop_hdr **p;
 244
 245         for (p = (struct prop_hdr **)&t->prop; *p; p = &(*p)->next) {
 246                 if (is_literal(*p)) {
 247                         if (type == NAME)
 248                                 return p;
 249                         break;
 250                 }
 251                 if ((*p)->type == type)
 252                         return p;
 253         }
 254         return NULL;
 255 }
 256
 257 static void *find_property(const struct tal_hdr *parent, enum prop_type type)
 258 {
 259         struct prop_hdr **p = find_property_ptr(parent, type);
 260
 261         if (p)
 262                 return *p;
 263         return NULL;
 264 }
 265
 266 static void init_property(struct prop_hdr *hdr,
 267                           struct tal_hdr *parent,
 268                           enum prop_type type)
 269 {
 270         hdr->type = type;
 271         hdr->next = parent->prop;
 272         parent->prop = hdr;
 273 }
 274
 275 static struct notifier *add_notifier_property(struct tal_hdr *t,
 276                                               enum tal_notify_type types,
 277                                               void (*fn)(void *,
 278                                                          enum tal_notify_type,
 279                                                          void *))
 280 {
 281         struct notifier *prop = allocate(sizeof(*prop));
 282         if (prop) {
 283                 init_property(&prop->hdr, t, NOTIFIER);
 284                 prop->types = types;
 285                 prop->u.notifyfn = fn;
 286         }
 287         return prop;
 288 }
 289
 290 static enum tal_notify_type del_notifier_property(struct tal_hdr *t,
 291                                                   void (*fn)(tal_t *,
 292                                                              enum tal_notify_type,
 293                                                              void *))
 294 {
 295         struct prop_hdr **p;
 296
 297         for (p = (struct prop_hdr **)&t->prop; *p; p = &(*p)->next) {
 298                 struct notifier *n;
 299
 300                 if (is_literal(*p))
 301                         break;
 302                 if ((*p)->type != NOTIFIER)
 303                         continue;
 304                 n = (struct notifier *)*p;
 305                 if (n->u.notifyfn == fn) {
 306                         enum tal_notify_type types = n->types;
 307                         *p = (*p)->next;
 308                         freefn(n);
 309                         return types & ~NOTIFY_IS_DESTRUCTOR;
 310                 }
 311         }
 312         return 0;
 313 }
 314
 315 static struct name *add_name_property(struct tal_hdr *t, const char *name)
 316 {
 317         struct name *prop;
 318
 319         prop = allocate(sizeof(*prop) + strlen(name) + 1);
 320         if (prop) {
 321                 init_property(&prop->hdr, t, NAME);
 322                 strcpy(prop->name, name);
 323         }
 324         return prop;
 325 }
 326
 327 static struct children *add_child_property(struct tal_hdr *parent,
 328                                            struct tal_hdr *child UNNEEDED)
 329 {
 330         struct children *prop = allocate(sizeof(*prop));
 331         if (prop) {
 332                 init_property(&prop->hdr, parent, CHILDREN);
 333                 prop->parent = parent;
 334                 list_head_init(&prop->children);
 335         }
 336         return prop;
 337 }
 338
 339 static bool add_child(struct tal_hdr *parent, struct tal_hdr *child)
 340 {
 341         struct children *children = find_property(parent, CHILDREN);
 342
 343         if (!children) {
 344                 children = add_child_property(parent, child);
 345                 if (!children)
 346                         return false;
 347         }
 348         list_add(&children->children, &child->list);
 349         child->parent_child = children;
 350         return true;
 351 }
 352
 353 static void del_tree(struct tal_hdr *t, const tal_t *orig, int saved_errno)
 354 {
 355         struct prop_hdr **prop, *p, *next;
 356
 357         /* Already being destroyed?  Don't loop. */
 358         if (unlikely(get_destroying_bit(t->parent_child)))
 359                 return;
 360
 361         set_destroying_bit(&t->parent_child);
 362
 363         /* Call free notifiers. */
 364         notify(t, TAL_NOTIFY_FREE, (tal_t *)orig, saved_errno);
 365
 366         /* Now free children and groups. */
 367         prop = find_property_ptr(t, CHILDREN);
 368         if (prop) {
 369                 struct tal_hdr *i;
 370                 struct children *c = (struct children *)*prop;
 371
 372                 while ((i = list_top(&c->children, struct tal_hdr, list))) {
 373                         list_del(&i->list);
 374                         del_tree(i, orig, saved_errno);
 375                 }
 376         }
 377
 378         /* Finally free our properties. */
 379         for (p = t->prop; p && !is_literal(p); p = next) {
 380                 next = p->next;
 381                 /* LENGTH is appended, so don't free separately! */
 382                 if (p->type != LENGTH)
 383                         freefn(p);
 384         }
 385         freefn(t);
 386 }
 387
 388 static size_t extra_for_length(size_t size)
 389 {
 390         size_t extra;
 391         const size_t align = ALIGNOF(struct length);
 392
 393         /* Round up size, and add tailer. */
 394         extra = ((size + align-1) & ~(align-1)) - size;
 395         extra += sizeof(struct length);
 396         return extra;
 397 }
 398
 399 void *tal_alloc_(const tal_t *ctx, size_t size,
 400                  bool clear, bool add_length, const char *label)
 401 {
 402         size_t req_size = size;
 403         struct tal_hdr *child, *parent = debug_tal(to_tal_hdr_or_null(ctx));
 404
 405 #ifdef CCAN_TAL_DEBUG
 406         /* Always record length if debugging. */
 407         add_length = true;
 408 #endif
 409         if (add_length)
 410                 size += extra_for_length(size);
 411
 412         child = allocate(sizeof(struct tal_hdr) + size);
 413         if (!child)
 414                 return NULL;
 415         if (clear)
 416                 memset(from_tal_hdr(child), 0, req_size);
 417         child->prop = (void *)label;
 418
 419         if (add_length) {
 420                 struct length *lprop;
 421                 lprop = (struct length *)((char *)(child+1) + size) - 1;
 422                 init_property(&lprop->hdr, child, LENGTH);
 423                 lprop->len = req_size;
 424         }
 425         if (!add_child(parent, child)) {
 426                 freefn(child);
 427                 return NULL;
 428         }
 429         debug_tal(parent);
 430         if (notifiers)
 431                 notify(parent, TAL_NOTIFY_ADD_CHILD, from_tal_hdr(child), 0);
 432         return from_tal_hdr(debug_tal(child));
 433 }
 434
 435 static bool adjust_size(size_t *size, size_t count)
 436 {
 437         const size_t extra = sizeof(struct tal_hdr) + sizeof(struct length)*2;
 438
 439         /* Multiplication wrap */
 440         if (count && unlikely(*size * count / *size != count))
 441                 goto overflow;
 442
 443         *size *= count;
 444
 445         /* Make sure we don't wrap adding header/tailer. */
 446         if (*size + extra < extra)
 447                 goto overflow;
 448         return true;
 449 overflow:
 450         call_error("allocation size overflow");
 451         return false;
 452 }
 453
 454 void *tal_alloc_arr_(const tal_t *ctx, size_t size, size_t count, bool clear,
 455                      bool add_length, const char *label)
 456 {
 457         if (!adjust_size(&size, count))
 458                 return NULL;
 459
 460         return tal_alloc_(ctx, size, clear, add_length, label);
 461 }
 462
 463 void *tal_free(const tal_t *ctx)
 464 {
 465         if (ctx) {
 466                 struct tal_hdr *t;
 467                 int saved_errno = errno;
 468                 t = debug_tal(to_tal_hdr(ctx));
 469                 if (notifiers)
 470                         notify(ignore_destroying_bit(t->parent_child)->parent,
 471                                TAL_NOTIFY_DEL_CHILD, ctx, saved_errno);
 472                 list_del(&t->list);
 473                 del_tree(t, ctx, saved_errno);
 474                 errno = saved_errno;
 475         }
 476         return NULL;
 477 }
 478
 479 void *tal_steal_(const tal_t *new_parent, const tal_t *ctx)
 480 {
 481         if (ctx) {
 482                 struct tal_hdr *newpar, *t, *old_parent;
 483
 484                 newpar = debug_tal(to_tal_hdr_or_null(new_parent));
 485                 t = debug_tal(to_tal_hdr(ctx));
 486
 487                 /* Unlink it from old parent. */
 488                 list_del(&t->list);
 489                 old_parent = ignore_destroying_bit(t->parent_child)->parent;
 490
 491                 if (unlikely(!add_child(newpar, t))) {
 492                         /* We can always add to old parent, becuase it has a
 493                          * children property already. */
 494                         if (!add_child(old_parent, t))
 495                                 abort();
 496                         return NULL;
 497                 }
 498                 debug_tal(newpar);
 499                 if (notifiers)
 500                         notify(t, TAL_NOTIFY_STEAL, new_parent, 0);
 501         }
 502         return (void *)ctx;
 503 }
 504
 505 bool tal_add_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 506 {
 507         tal_t *t = debug_tal(to_tal_hdr(ctx));
 508         return add_notifier_property(t, TAL_NOTIFY_FREE|NOTIFY_IS_DESTRUCTOR,
 509                                      (void *)destroy);
 510 }
 511
 512 bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
 513                        void (*callback)(tal_t *, enum tal_notify_type, void *))
 514 {
 515         tal_t *t = debug_tal(to_tal_hdr(ctx));
 516         struct notifier *n;
 517
 518         assert(types);
 519         assert((types & ~(TAL_NOTIFY_FREE | TAL_NOTIFY_STEAL | TAL_NOTIFY_MOVE
 520                           | TAL_NOTIFY_RESIZE | TAL_NOTIFY_RENAME
 521                           | TAL_NOTIFY_ADD_CHILD | TAL_NOTIFY_DEL_CHILD
 522                           | TAL_NOTIFY_ADD_NOTIFIER
 523                           | TAL_NOTIFY_DEL_NOTIFIER)) == 0);
 524
 525         /* Don't call notifier about itself: set types after! */
 526         n = add_notifier_property(t, 0, callback);
 527         if (unlikely(!n))
 528                 return false;
 529
 530         if (notifiers)
 531                 notify(t, TAL_NOTIFY_ADD_NOTIFIER, callback, 0);
 532
 533         n->types = types;
 534         if (types != TAL_NOTIFY_FREE)
 535                 notifiers++;
 536         return true;
 537 }
 538
 539 bool tal_del_notifier_(const tal_t *ctx,
 540                        void (*callback)(tal_t *, enum tal_notify_type, void *))
 541 {
 542         struct tal_hdr *t = debug_tal(to_tal_hdr(ctx));
 543         enum tal_notify_type types;
 544
 545         types = del_notifier_property(t, callback);
 546         if (types) {
 547                 notify(t, TAL_NOTIFY_DEL_NOTIFIER, callback, 0);
 548                 if (types != TAL_NOTIFY_FREE)
 549                         notifiers--;
 550                 return true;
 551         }
 552         return false;
 553 }
 554
 555 bool tal_del_destructor_(const tal_t *ctx, void (*destroy)(void *me))
 556 {
 557         return tal_del_notifier_(ctx, (void *)destroy);
 558 }
 559
 560 bool tal_set_name_(tal_t *ctx, const char *name, bool literal)
 561 {
 562         struct tal_hdr *t = debug_tal(to_tal_hdr(ctx));
 563         struct prop_hdr **prop = find_property_ptr(t, NAME);
 564
 565         /* Get rid of any old name */
 566         if (prop) {
 567                 struct name *name = (struct name *)*prop;
 568                 if (is_literal(&name->hdr))
 569                         *prop = NULL;
 570                 else {
 571                         *prop = name->hdr.next;
 572                         freefn(name);
 573                 }
 574         }
 575
 576         if (literal && name[0]) {
 577                 struct prop_hdr **p;
 578
 579                 /* Append literal. */
 580                 for (p = &t->prop; *p && !is_literal(*p); p = &(*p)->next);
 581                 *p = (struct prop_hdr *)name;
 582         } else if (!add_name_property(t, name))
 583                 return false;
 584
 585         debug_tal(t);
 586         if (notifiers)
 587                 notify(t, TAL_NOTIFY_RENAME, name, 0);
 588         return true;
 589 }
 590
 591 const char *tal_name(const tal_t *t)
 592 {
 593         struct name *n;
 594
 595         n = find_property(debug_tal(to_tal_hdr(t)), NAME);
 596         if (!n)
 597                 return NULL;
 598
 599         if (is_literal(&n->hdr))
 600                 return (const char *)n;
 601         return n->name;
 602 }
 603
 604 size_t tal_len(const tal_t *ptr)
 605 {
 606         struct length *l;
 607
 608         l = find_property(debug_tal(to_tal_hdr(ptr)), LENGTH);
 609         if (!l)
 610                 return 0;
 611         return l->len;
 612 }
 613
 614 /* Start one past first child: make stopping natural in circ. list. */
 615 static struct tal_hdr *first_child(struct tal_hdr *parent)
 616 {
 617         struct children *child;
 618
 619         child = find_property(parent, CHILDREN);
 620         if (!child)
 621                 return NULL;
 622
 623         return list_top(&child->children, struct tal_hdr, list);
 624 }
 625
 626 tal_t *tal_first(const tal_t *root)
 627 {
 628         struct tal_hdr *c, *t = debug_tal(to_tal_hdr_or_null(root));
 629
 630         c = first_child(t);
 631         if (!c)
 632                 return NULL;
 633         return from_tal_hdr(c);
 634 }
 635
 636 tal_t *tal_next(const tal_t *prev)
 637 {
 638         struct tal_hdr *next, *prevhdr = debug_tal(to_tal_hdr(prev));
 639         struct list_head *head;
 640
 641         head = &ignore_destroying_bit(prevhdr->parent_child)->children;
 642         next = list_next(head, prevhdr, list);
 643         if (!next)
 644                 return NULL;
 645         return from_tal_hdr(next);
 646 }
 647
 648 tal_t *tal_parent(const tal_t *ctx)
 649 {
 650         struct tal_hdr *t;
 651
 652         if (!ctx)
 653                 return NULL;
 654
 655         t = debug_tal(to_tal_hdr(ctx));
 656         if (ignore_destroying_bit(t->parent_child)->parent == &null_parent.hdr)
 657                 return NULL;
 658         return from_tal_hdr(ignore_destroying_bit(t->parent_child)->parent);
 659 }
 660
 661 bool tal_resize_(tal_t **ctxp, size_t size, size_t count, bool clear)
 662 {
 663         struct tal_hdr *old_t, *t;
 664         struct children *child;
 665         struct prop_hdr **lenp;
 666         struct length len;
 667         size_t extra = 0;
 668
 669         old_t = debug_tal(to_tal_hdr(*ctxp));
 670
 671         if (!adjust_size(&size, count))
 672                 return false;
 673
 674         lenp = find_property_ptr(old_t, LENGTH);
 675         if (lenp) {
 676                 /* Copy here, in case we're shrinking! */
 677                 len = *(struct length *)*lenp;
 678                 extra = extra_for_length(size);
 679         } else /* If we don't have an old length, we can't clear! */
 680                 assert(!clear);
 681
 682         t = resizefn(old_t, sizeof(struct tal_hdr) + size + extra);
 683         if (!t) {
 684                 call_error("Reallocation failure");
 685                 return false;
 686         }
 687
 688         /* Copy length to end. */
 689         if (lenp) {
 690                 struct length *new_len;
 691
 692                 /* Clear between old end and new end. */
 693                 if (clear && size > len.len) {
 694                         char *old_end = (char *)(t + 1) + len.len;
 695                         memset(old_end, 0, size - len.len);
 696                 }
 697
 698                 new_len = (struct length *)((char *)(t + 1) + size
 699                                             + extra - sizeof(len));
 700                 len.len = size;
 701                 *new_len = len;
 702
 703                 /* Be careful replacing next ptr; could be old hdr. */
 704                 if (lenp == &old_t->prop)
 705                         t->prop = &new_len->hdr;
 706                 else
 707                         *lenp = &new_len->hdr;
 708         }
 709
 710         update_bounds(t, sizeof(struct tal_hdr) + size + extra);
 711
 712         /* If it didn't move, we're done! */
 713         if (t != old_t) {
 714                 /* Fix up linked list pointers. */
 715                 t->list.next->prev = t->list.prev->next = &t->list;
 716
 717                 /* Fix up child property's parent pointer. */
 718                 child = find_property(t, CHILDREN);
 719                 if (child) {
 720                         assert(child->parent == old_t);
 721                         child->parent = t;
 722                 }
 723                 *ctxp = from_tal_hdr(debug_tal(t));
 724                 if (notifiers)
 725                         notify(t, TAL_NOTIFY_MOVE, from_tal_hdr(old_t), 0);
 726         }
 727         if (notifiers)
 728                 notify(t, TAL_NOTIFY_RESIZE, (void *)size, 0);
 729
 730         return true;
 731 }
 732
 733 bool tal_expand_(tal_t **ctxp, const void *src, size_t size, size_t count)
 734 {
 735         struct length *l;
 736         size_t old_len;
 737         bool ret = false;
 738
 739         l = find_property(debug_tal(to_tal_hdr(*ctxp)), LENGTH);
 740         old_len = l->len;
 741
 742         /* Check for additive overflow */
 743         if (old_len + count * size < old_len) {
 744                 call_error("dup size overflow");
 745                 goto out;
 746         }
 747
 748         /* Don't point src inside thing we're expanding! */
 749         assert(src < *ctxp
 750                || (char *)src >= (char *)(*ctxp) + old_len);
 751
 752         if (!tal_resize_(ctxp, size, old_len/size + count, false))
 753                 goto out;
 754
 755         memcpy((char *)*ctxp + old_len, src, count * size);
 756         ret = true;
 757
 758 out:
 759         if (taken(src))
 760                 tal_free(src);
 761         return ret;
 762 }
 763
 764 void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
 765                size_t n, size_t extra, bool add_length,
 766                const char *label)
 767 {
 768         void *ret;
 769         size_t nbytes = size;
 770
 771         if (!adjust_size(&nbytes, n)) {
 772                 if (taken(p))
 773                         tal_free(p);
 774                 return NULL;
 775         }
 776
 777         /* Beware addition overflow! */
 778         if (n + extra < n) {
 779                 call_error("dup size overflow");
 780                 if (taken(p))
 781                         tal_free(p);
 782                 return NULL;
 783         }
 784
 785         if (taken(p)) {
 786                 if (unlikely(!p))
 787                         return NULL;
 788                 if (unlikely(!tal_resize_((void **)&p, size, n + extra, false)))
 789                         return tal_free(p);
 790                 if (unlikely(!tal_steal(ctx, p)))
 791                         return tal_free(p);
 792                 return (void *)p;
 793         }
 794
 795         ret = tal_alloc_arr_(ctx, size, n + extra, false, add_length, label);
 796         if (ret)
 797                 memcpy(ret, p, nbytes);
 798         return ret;
 799 }
 800
 801 void tal_set_backend(void *(*alloc_fn)(size_t size),
 802                      void *(*resize_fn)(void *, size_t size),
 803                      void (*free_fn)(void *),
 804                      void (*error_fn)(const char *msg))
 805 {
 806         if (alloc_fn)
 807                 allocfn = alloc_fn;
 808         if (resize_fn)
 809                 resizefn = resize_fn;
 810         if (free_fn)
 811                 freefn = free_fn;
 812         if (error_fn)
 813                 errorfn = error_fn;
 814 }
 815
 816 #ifdef CCAN_TAL_DEBUG
 817 static void dump_node(unsigned int indent, const struct tal_hdr *t)
 818 {
 819         unsigned int i;
 820         const struct prop_hdr *p;
 821
 822         for (i = 0; i < indent; i++)
 823                 printf("  ");
 824         printf("%p", t);
 825         for (p = t->prop; p; p = p->next) {
 826                 struct children *c;
 827                 struct name *n;
 828                 struct notifier *no;
 829                 struct length *l;
 830                 if (is_literal(p)) {
 831                         printf(" \"%s\"", (const char *)p);
 832                         break;
 833                 }
 834                 switch (p->type) {
 835                 case CHILDREN:
 836                         c = (struct children *)p;
 837                         printf(" CHILDREN(%p):parent=%p,children={%p,%p}\n",
 838                                p, c->parent,
 839                                c->children.n.prev, c->children.n.next);
 840                         break;
 841                 case NAME:
 842                         n = (struct name *)p;
 843                         printf(" NAME(%p):%s", p, n->name);
 844                         break;
 845                 case NOTIFIER:
 846                         no = (struct notifier *)p;
 847                         printf(" NOTIFIER(%p):fn=%p", p, no->u.notifyfn);
 848                         break;
 849                 case LENGTH:
 850                         l = (struct length *)p;
 851                         printf(" LENGTH(%p):len=%zu", p, l->len);
 852                         break;
 853                 default:
 854                         printf(" **UNKNOWN(%p):%i**", p, p->type);
 855                 }
 856         }
 857         printf("\n");
 858 }
 859
 860 static void tal_dump_(unsigned int level, const struct tal_hdr *t)
 861 {
 862         struct children *children;
 863
 864         dump_node(level, t);
 865
 866         children = find_property(t, CHILDREN);
 867         if (children) {
 868                 struct tal_hdr *i;
 869
 870                 list_for_each(&children->children, i, list)
 871                         tal_dump_(level + 1, i);
 872         }
 873 }
 874
 875 void tal_dump(void)
 876 {
 877         tal_dump_(0, &null_parent.hdr);
 878 }
 879 #endif /* CCAN_TAL_DEBUG */
 880
 881 #ifndef NDEBUG
 882 static bool check_err(struct tal_hdr *t, const char *errorstr,
 883                       const char *errmsg)
 884 {
 885         if (errorstr) {
 886                 /* Try not to malloc: it may be corrupted. */
 887                 char msg[strlen(errorstr) + 20 + strlen(errmsg) + 1];
 888                 sprintf(msg, "%s:%p %s", errorstr, from_tal_hdr(t), errmsg);
 889                 call_error(msg);
 890         }
 891         return false;
 892 }
 893
 894 static bool check_node(struct children *parent_child,
 895                        struct tal_hdr *t, const char *errorstr)
 896 {
 897         struct prop_hdr *p;
 898         struct name *name = NULL;
 899         struct children *children = NULL;
 900         struct length *length = NULL;
 901
 902         if (!in_bounds(t))
 903                 return check_err(t, errorstr, "invalid pointer");
 904
 905         if (ignore_destroying_bit(t->parent_child) != parent_child)
 906                 return check_err(t, errorstr, "incorrect parent");
 907
 908         for (p = t->prop; p; p = p->next) {
 909                 if (is_literal(p)) {
 910                         if (name)
 911                                 return check_err(t, errorstr,
 912                                                  "has extra literal");
 913                         break;
 914                 }
 915                 if (!in_bounds(p))
 916                         return check_err(t, errorstr,
 917                                          "has bad property pointer");
 918
 919                 switch (p->type) {
 920                 case CHILDREN:
 921                         if (children)
 922                                 return check_err(t, errorstr,
 923                                                  "has two child nodes");
 924                         children = (struct children *)p;
 925                         break;
 926                 case LENGTH:
 927                         if (length)
 928                                 return check_err(t, errorstr,
 929                                                  "has two lengths");
 930                         length = (struct length *)p;
 931                         break;
 932                 case NOTIFIER:
 933                         break;
 934                 case NAME:
 935                         if (name)
 936                                 return check_err(t, errorstr,
 937                                                  "has two names");
 938                         name = (struct name *)p;
 939                         break;
 940                 default:
 941                         return check_err(t, errorstr, "has unknown property");
 942                 }
 943         }
 944         if (children) {
 945                 struct tal_hdr *i;
 946
 947                 if (!list_check(&children->children, errorstr))
 948                         return false;
 949                 list_for_each(&children->children, i, list) {
 950                         if (!check_node(children, i, errorstr))
 951                                 return false;
 952                 }
 953         }
 954         return true;
 955 }
 956
 957 bool tal_check(const tal_t *ctx, const char *errorstr)
 958 {
 959         struct tal_hdr *t = to_tal_hdr_or_null(ctx);
 960
 961         return check_node(ignore_destroying_bit(t->parent_child), t, errorstr);
 962 }
 963 #else /* NDEBUG */
 964 bool tal_check(const tal_t *ctx, const char *errorstr)
 965 {
 966         return true;
 967 }
 968 #endif