1/** 2 * @file 3 * Dynamic memory manager 4 * 5 * This is a lightweight replacement for the standard C library malloc(). 6 * 7 * If you want to use the standard C library malloc() instead, define 8 * MEM_LIBC_MALLOC to 1 in your lwipopts.h 9 * 10 * To let mem_malloc() use pools (prevents fragmentation and is much faster than 11 * a heap but might waste some memory), define MEM_USE_POOLS to 1, define 12 * MEM_USE_CUSTOM_POOLS to 1 and create a file "lwippools.h" that includes a list 13 * of pools like this (more pools can be added between _START and _END): 14 * 15 * Define three pools with sizes 256, 512, and 1512 bytes 16 * LWIP_MALLOC_MEMPOOL_START 17 * LWIP_MALLOC_MEMPOOL(20, 256) 18 * LWIP_MALLOC_MEMPOOL(10, 512) 19 * LWIP_MALLOC_MEMPOOL(5, 1512) 20 * LWIP_MALLOC_MEMPOOL_END 21 */ 22 23/* 24 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 25 * All rights reserved. 26 * 27 * Redistribution and use in source and binary forms, with or without modification, 28 * are permitted provided that the following conditions are met: 29 * 30 * 1. Redistributions of source code must retain the above copyright notice, 31 * this list of conditions and the following disclaimer. 32 * 2. Redistributions in binary form must reproduce the above copyright notice, 33 * this list of conditions and the following disclaimer in the documentation 34 * and/or other materials provided with the distribution. 35 * 3. The name of the author may not be used to endorse or promote products 36 * derived from this software without specific prior written permission. 37 * 38 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 39 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 40 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 41 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 42 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 43 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 44 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 45 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 46 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 47 * OF SUCH DAMAGE. 48 * 49 * This file is part of the lwIP TCP/IP stack. 50 * 51 * Author: Adam Dunkels <adam@sics.se> 52 * Simon Goldschmidt 53 * 54 */ 55 56#include "lwip/opt.h" 57 58#if !MEM_LIBC_MALLOC /* don't build if not configured for use in lwipopts.h */ 59 60#include "lwip/def.h" 61#include "lwip/mem.h" 62#include "lwip/sys.h" 63#include "lwip/stats.h" 64 65#include <string.h> 66#include <assert.h> 67#include <barrelfish/barrelfish.h> 68 69 70 71#if MEM_USE_POOLS 72/* lwIP head implemented with different sized pools */ 73 74/** 75 * Allocate memory: determine the smallest pool that is big enough 76 * to contain an element of 'size' and get an element from that pool. 77 * 78 * @param size the size in bytes of the memory needed 79 * @return a pointer to the allocated memory or NULL if the pool is empty 80 */ 81void *mem_malloc(mem_size_t size) 82{ 83 struct memp_malloc_helper *element; 84 memp_t poolnr; 85 mem_size_t required_size = size + sizeof(struct memp_malloc_helper); 86 87 for (poolnr = MEMP_POOL_FIRST; poolnr <= MEMP_POOL_LAST; poolnr++) { 88#if MEM_USE_POOLS_TRY_BIGGER_POOL 89 again: 90#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */ 91 /* is this pool big enough to hold an element of the required size 92 plus a struct memp_malloc_helper that saves the pool this element came from? */ 93 if (required_size <= memp_sizes[poolnr]) { 94 break; 95 } 96 } 97 if (poolnr > MEMP_POOL_LAST) { 98 LWIP_ASSERT("mem_malloc(): no pool is that big!", 0); 99 return NULL; 100 } 101 element = (struct memp_malloc_helper *) memp_malloc(poolnr); 102 if (element == NULL) { 103 /* No need to DEBUGF or ASSERT: This error is already 104 taken care of in memp.c */ 105#if MEM_USE_POOLS_TRY_BIGGER_POOL 106 /** Try a bigger pool if this one is empty! */ 107 if (poolnr < MEMP_POOL_LAST) { 108 poolnr++; 109 goto again; 110 } 111#endif /* MEM_USE_POOLS_TRY_BIGGER_POOL */ 112 return NULL; 113 } 114 115 /* save the pool number this element came from */ 116 element->poolnr = poolnr; 117 /* and return a pointer to the memory directly after the struct memp_malloc_helper */ 118 element++; 119 120 return element; 121} 122 123/** 124 * Free memory previously allocated by mem_malloc. Loads the pool number 125 * and calls memp_free with that pool number to put the element back into 126 * its pool 127 * 128 * @param rmem the memory element to free 129 */ 130void mem_free(void *rmem) 131{ 132 struct memp_malloc_helper *hmem = (struct memp_malloc_helper *) rmem; 133 134 LWIP_ASSERT("rmem != NULL", (rmem != NULL)); 135 LWIP_ASSERT("rmem == MEM_ALIGN(rmem)", (rmem == LWIP_MEM_ALIGN(rmem))); 136 137 /* get the original struct memp_malloc_helper */ 138 hmem--; 139 140 LWIP_ASSERT("hmem != NULL", (hmem != NULL)); 141 LWIP_ASSERT("hmem == MEM_ALIGN(hmem)", (hmem == LWIP_MEM_ALIGN(hmem))); 142 LWIP_ASSERT("hmem->poolnr < MEMP_MAX", (hmem->poolnr < MEMP_MAX)); 143 144 /* and put it in the pool we saved earlier */ 145 memp_free(hmem->poolnr, hmem); 146} 147 148#else /* MEM_USE_POOLS */ 149/* lwIP replacement for your libc malloc() */ 150 151/** 152 * The heap is made up as a list of structs of this type. 153 * This does not have to be aligned since for getting its size, 154 * we only use the macro SIZEOF_STRUCT_MEM, which automatically alignes. 155 */ 156struct mem { 157 /** index (-> ram[next]) of the next struct */ 158 mem_size_t next; 159 /** index (-> ram[next]) of the next struct */ 160 mem_size_t prev; 161 /** 1: this area is used; 0: this area is unused */ 162 u8_t used; 163}; 164 165/** All allocated blocks will be MIN_SIZE bytes big, at least! 166 * MIN_SIZE can be overridden to suit your needs. Smaller values save space, 167 * larger values could prevent too small blocks to fragment the RAM too much. */ 168#ifndef MIN_SIZE 169#define MIN_SIZE 12 170#endif /* MIN_SIZE */ 171/* some alignment macros: we define them here for better source code layout */ 172#define MIN_SIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(MIN_SIZE) 173#define SIZEOF_STRUCT_MEM LWIP_MEM_ALIGN_SIZE(sizeof(struct mem)) 174#define MEM_SIZE_ALIGNED LWIP_MEM_ALIGN_SIZE(MEM_SIZE) 175 176/** the heap. we need one struct mem at the end and some room for alignment */ 177//static u8_t ram_heap[MEM_SIZE_ALIGNED + (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT]; 178u8_t *mem_barrelfish_alloc(uint8_t buf_index, uint32_t size); 179u8_t *mem_barrelfish_register_buf(uint8_t binding_index, uint32_t size); 180 181static u8_t *ram_heap = 0; 182 183/** pointer to the heap (ram_heap): for alignment, ram is now a pointer instead of an array */ 184static u8_t *ram; 185 186/** the last entry, always unused! */ 187static struct mem *ram_end; 188 189/** pointer to the lowest free block, this is used for faster search */ 190static struct mem *lfree; 191 192/** concurrent access protection */ 193static sys_sem_t mem_sem; 194 195#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 196 197static volatile u8_t mem_free_count; 198 199/* Allow mem_free from other (e.g. interrupt) context */ 200#define LWIP_MEM_FREE_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_free) 201#define LWIP_MEM_FREE_PROTECT() SYS_ARCH_PROTECT(lev_free) 202#define LWIP_MEM_FREE_UNPROTECT() SYS_ARCH_UNPROTECT(lev_free) 203#define LWIP_MEM_ALLOC_DECL_PROTECT() SYS_ARCH_DECL_PROTECT(lev_alloc) 204#define LWIP_MEM_ALLOC_PROTECT() SYS_ARCH_PROTECT(lev_alloc) 205#define LWIP_MEM_ALLOC_UNPROTECT() SYS_ARCH_UNPROTECT(lev_alloc) 206 207#else /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 208 209/* Protect the heap only by using a semaphore */ 210#define LWIP_MEM_FREE_DECL_PROTECT() 211#define LWIP_MEM_FREE_PROTECT() sys_arch_sem_wait(mem_sem, 0) 212#define LWIP_MEM_FREE_UNPROTECT() sys_sem_signal(mem_sem) 213/* mem_malloc is protected using semaphore AND LWIP_MEM_ALLOC_PROTECT */ 214#define LWIP_MEM_ALLOC_DECL_PROTECT() 215#define LWIP_MEM_ALLOC_PROTECT() 216#define LWIP_MEM_ALLOC_UNPROTECT() 217 218#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 219 220 221/** 222 * "Plug holes" by combining adjacent empty struct mems. 223 * After this function is through, there should not exist 224 * one empty struct mem pointing to another empty struct mem. 225 * 226 * @param mem this points to a struct mem which just has been freed 227 * @internal this function is only called by mem_free() and mem_realloc() 228 * 229 * This assumes access to the heap is protected by the calling function 230 * already. 231 */ 232static void plug_holes(struct mem *mem) 233{ 234 struct mem *nmem; 235 struct mem *pmem; 236 237 LWIP_ASSERT("plug_holes: mem >= ram", (u8_t *) mem >= ram); 238 LWIP_ASSERT("plug_holes: mem < ram_end", (u8_t *) mem < (u8_t *) ram_end); 239 LWIP_ASSERT("plug_holes: mem->used == 0", mem->used == 0); 240 241 /* plug hole forward */ 242 LWIP_ASSERT("plug_holes: mem->next <= MEM_SIZE_ALIGNED", 243 mem->next <= MEM_SIZE_ALIGNED); 244 245 nmem = (struct mem *) &ram[mem->next]; 246 if (mem != nmem && nmem->used == 0 && (u8_t *) nmem != (u8_t *) ram_end) { 247 /* if mem->next is unused and not end of ram, combine mem and mem->next */ 248 if (lfree == nmem) { 249 lfree = mem; 250 } 251 mem->next = nmem->next; 252 ((struct mem *) &ram[nmem->next])->prev = (u8_t *) mem - ram; 253 } 254 255 /* plug hole backward */ 256 pmem = (struct mem *) &ram[mem->prev]; 257 if (pmem != mem && pmem->used == 0) { 258 /* if mem->prev is unused, combine mem and mem->prev */ 259 if (lfree == mem) { 260 lfree = pmem; 261 } 262 pmem->next = mem->next; 263 ((struct mem *) &ram[mem->next])->prev = (u8_t *) pmem - ram; 264 } 265} 266 267/** 268 * Zero the heap and initialize start, end and lowest-free 269 */ 270void mem_init(void) 271{ 272 size_t bufsize = MEM_SIZE_ALIGNED + (2 * SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT; 273 struct mem *mem; 274 275// printf("@@@@@@ mem alloc %lx, %lx for index %d\n", MEM_SIZE_ALIGNED + 276// (2*SIZEOF_STRUCT_MEM) + MEM_ALIGNMENT, bufsize, TX_BUFFER_ID); 277 278 279 ram_heap = mem_barrelfish_alloc(TX_BUFFER_ID, bufsize); 280 281 LWIP_ASSERT("Sanity check alignment", 282 (SIZEOF_STRUCT_MEM & (MEM_ALIGNMENT - 1)) == 0); 283 284 /* align the heap */ 285 ram = LWIP_MEM_ALIGN(ram_heap); 286 /* initialize the start of the heap */ 287 mem = (struct mem *) ram; 288 mem->next = MEM_SIZE_ALIGNED; 289 mem->prev = 0; 290 mem->used = 0; 291 /* initialize the end of the heap */ 292 ram_end = (struct mem *) &ram[MEM_SIZE_ALIGNED]; 293 ram_end->used = 1; 294 ram_end->next = MEM_SIZE_ALIGNED; 295 ram_end->prev = MEM_SIZE_ALIGNED; 296 mem_sem = sys_sem_new(1); 297 298 /* initialize the lowest-free pointer to the start of the heap */ 299 lfree = (struct mem *) ram; 300 MEM_STATS_AVAIL(avail, MEM_SIZE_ALIGNED); 301 mem_barrelfish_register_buf(TX_BUFFER_ID, bufsize); 302} 303 304/** 305 * Put a struct mem back on the heap 306 * 307 * @param rmem is the data portion of a struct mem as returned by a previous 308 * call to mem_malloc() 309 */ 310void mem_free(void *rmem) 311{ 312 struct mem *mem; 313 314 LWIP_MEM_FREE_DECL_PROTECT(); 315 316 if (rmem == NULL) { 317 LWIP_DEBUGF(MEM_DEBUG | LWIP_DBG_TRACE | 2, 318 ("mem_free(p == NULL) was called.\n")); 319 return; 320 } 321 LWIP_ASSERT("mem_free: sanity check alignment", 322 (((mem_ptr_t) rmem) & (MEM_ALIGNMENT - 1)) == 0); 323 324 if ((u8_t *) rmem >= (u8_t *) ram && 325 (u8_t *) rmem < (u8_t *) ram_end) { 326 // everything is great 327 } else { 328 printf("assertion failef for rmem %p\n", rmem); 329 printf("condition was ram %p <= rmem %p < ram_end %p\n", 330 ram, rmem, ram_end); 331 } 332 LWIP_ASSERT("mem_free: legal memory", (u8_t *) rmem >= (u8_t *) ram && 333 (u8_t *) rmem < (u8_t *) ram_end); 334 335 if ((u8_t *) rmem < (u8_t *) ram || (u8_t *) rmem >= (u8_t *) ram_end) { 336 SYS_ARCH_DECL_PROTECT(lev); 337 LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_free: illegal memory\n")); 338 /* protect mem stats from concurrent access */ 339 SYS_ARCH_PROTECT(lev); 340 MEM_STATS_INC(illegal); 341 SYS_ARCH_UNPROTECT(lev); 342 return; 343 } 344 /* protect the heap from concurrent access */ 345 LWIP_MEM_FREE_PROTECT(); 346 /* Get the corresponding struct mem ... */ 347 mem = (struct mem *) ((u8_t *) rmem - SIZEOF_STRUCT_MEM); 348 /* ... which has to be in a used state ... */ 349 LWIP_ASSERT("mem_free: mem->used", mem->used); 350 /* ... and is now unused. */ 351 mem->used = 0; 352 353 if (mem < lfree) { 354 /* the newly freed struct is now the lowest */ 355 lfree = mem; 356 } 357 358 MEM_STATS_DEC_USED(used, mem->next - ((u8_t *) mem - ram)); 359 360 /* finally, see if prev or next are free also */ 361 plug_holes(mem); 362#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 363 mem_free_count = 1; 364#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 365 LWIP_MEM_FREE_UNPROTECT(); 366} 367 368/** 369 * In contrast to its name, mem_realloc can only shrink memory, not expand it. 370 * Since the only use (for now) is in pbuf_realloc (which also can only shrink), 371 * this shouldn't be a problem! 372 * 373 * @param rmem pointer to memory allocated by mem_malloc the is to be shrinked 374 * @param newsize required size after shrinking (needs to be smaller than or 375 * equal to the previous size) 376 * @return for compatibility reasons: is always == rmem, at the moment 377 * or NULL if newsize is > old size, in which case rmem is NOT touched 378 * or freed! 379 */ 380void *mem_realloc(void *rmem, mem_size_t newsize) 381{ 382 383 mem_size_t size; 384 mem_size_t ptr, ptr2; 385 struct mem *mem, *mem2; 386 387 /* use the FREE_PROTECT here: it protects with sem OR SYS_ARCH_PROTECT */ 388 LWIP_MEM_FREE_DECL_PROTECT(); 389 390 /* Expand the size of the allocated memory region so that we can 391 adjust for alignment. */ 392 newsize = LWIP_MEM_ALIGN_SIZE(newsize); 393 394 if (newsize < MIN_SIZE_ALIGNED) { 395 /* every data block must be at least MIN_SIZE_ALIGNED long */ 396 newsize = MIN_SIZE_ALIGNED; 397 } 398 399 if (newsize > MEM_SIZE_ALIGNED) { 400 return NULL; 401 } 402 403 LWIP_ASSERT("mem_realloc: legal memory", (u8_t *) rmem >= (u8_t *) ram && 404 (u8_t *) rmem < (u8_t *) ram_end); 405 406 if ((u8_t *) rmem < (u8_t *) ram || (u8_t *) rmem >= (u8_t *) ram_end) { 407 SYS_ARCH_DECL_PROTECT(lev); 408 LWIP_DEBUGF(MEM_DEBUG | 3, ("mem_realloc: illegal memory\n")); 409 /* protect mem stats from concurrent access */ 410 SYS_ARCH_PROTECT(lev); 411 MEM_STATS_INC(illegal); 412 SYS_ARCH_UNPROTECT(lev); 413 return rmem; 414 } 415 /* Get the corresponding struct mem ... */ 416 mem = (struct mem *) ((u8_t *) rmem - SIZEOF_STRUCT_MEM); 417 /* ... and its offset pointer */ 418 ptr = (u8_t *) mem - ram; 419 420 size = mem->next - ptr - SIZEOF_STRUCT_MEM; 421 LWIP_ASSERT("mem_realloc can only shrink memory", newsize <= size); 422 if (newsize > size) { 423 /* not supported */ 424 return NULL; 425 } 426 if (newsize == size) { 427 /* No change in size, simply return */ 428 return rmem; 429 } 430 431 /* protect the heap from concurrent access */ 432 LWIP_MEM_FREE_PROTECT(); 433 434 MEM_STATS_DEC_USED(used, (size - newsize)); 435 436 mem2 = (struct mem *) &ram[mem->next]; 437 if (mem2->used == 0) { 438 /* The next struct is unused, we can simply move it at little */ 439 mem_size_t next; 440 441 /* remember the old next pointer */ 442 next = mem2->next; 443 /* create new struct mem which is moved directly after the shrinked mem */ 444 ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; 445 if (lfree == mem2) { 446 lfree = (struct mem *) &ram[ptr2]; 447 } 448 mem2 = (struct mem *) &ram[ptr2]; 449 mem2->used = 0; 450 /* restore the next pointer */ 451 mem2->next = next; 452 /* link it back to mem */ 453 mem2->prev = ptr; 454 /* link mem to it */ 455 mem->next = ptr2; 456 /* last thing to restore linked list: as we have moved mem2, 457 * let 'mem2->next->prev' point to mem2 again. but only if mem2->next is not 458 * the end of the heap */ 459 if (mem2->next != MEM_SIZE_ALIGNED) { 460 ((struct mem *) &ram[mem2->next])->prev = ptr2; 461 } 462 /* no need to plug holes, we've already done that */ 463 } else if (newsize + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED <= size) { 464 /* Next struct is used but there's room for another struct mem with 465 * at least MIN_SIZE_ALIGNED of data. 466 * Old size ('size') must be big enough to contain at least 'newsize' plus a struct mem 467 * ('SIZEOF_STRUCT_MEM') with some data ('MIN_SIZE_ALIGNED'). 468 * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty 469 * region that couldn't hold data, but when mem->next gets freed, 470 * the 2 regions would be combined, resulting in more free memory */ 471 ptr2 = ptr + SIZEOF_STRUCT_MEM + newsize; 472 mem2 = (struct mem *) &ram[ptr2]; 473 if (mem2 < lfree) { 474 lfree = mem2; 475 } 476 mem2->used = 0; 477 mem2->next = mem->next; 478 mem2->prev = ptr; 479 mem->next = ptr2; 480 if (mem2->next != MEM_SIZE_ALIGNED) { 481 ((struct mem *) &ram[mem2->next])->prev = ptr2; 482 } 483 /* the original mem->next is used, so no need to plug holes! */ 484 } 485 /* else { 486 next struct mem is used but size between mem and mem2 is not big enough 487 to create another struct mem 488 -> don't do anyhting. 489 -> the remaining space stays unused since it is too small 490 } */ 491#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 492 mem_free_count = 1; 493#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 494 LWIP_MEM_FREE_UNPROTECT(); 495 return rmem; 496} 497 498/** 499 * Adam's mem_malloc() plus solution for bug #17922 500 * Allocate a block of memory with a minimum of 'size' bytes. 501 * 502 * @param size is the minimum size of the requested block in bytes. 503 * @return pointer to allocated memory or NULL if no free memory was found. 504 * 505 * Note that the returned value will always be aligned (as defined by MEM_ALIGNMENT). 506 */ 507void *mem_malloc(mem_size_t size) 508{ 509 510 mem_size_t ptr, ptr2; 511 struct mem *mem, *mem2; 512 513#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 514 u8_t local_mem_free_count = 0; 515#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 516 LWIP_MEM_ALLOC_DECL_PROTECT(); 517 518 if (size == 0) { 519 return NULL; 520 } 521 522 /* Expand the size of the allocated memory region so that we can 523 adjust for alignment. */ 524 size = LWIP_MEM_ALIGN_SIZE(size); 525 526 if (size < MIN_SIZE_ALIGNED) { 527 /* every data block must be at least MIN_SIZE_ALIGNED long */ 528 size = MIN_SIZE_ALIGNED; 529 } 530 531 if (size > MEM_SIZE_ALIGNED) { 532 return NULL; 533 } 534 535 /* protect the heap from concurrent access */ 536 sys_arch_sem_wait(mem_sem, 0); 537 LWIP_MEM_ALLOC_PROTECT(); 538#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 539 /* run as long as a mem_free disturbed mem_malloc */ 540 do { 541 local_mem_free_count = 0; 542#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 543 544 /* Scan through the heap searching for a free block that is big enough, 545 * beginning with the lowest free block. 546 */ 547 for (ptr = (u8_t *) lfree - ram; ptr < MEM_SIZE_ALIGNED - size; 548 ptr = ((struct mem *) &ram[ptr])->next) { 549 mem = (struct mem *) &ram[ptr]; 550#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 551 mem_free_count = 0; 552 LWIP_MEM_ALLOC_UNPROTECT(); 553 /* allow mem_free to run */ 554 LWIP_MEM_ALLOC_PROTECT(); 555 if (mem_free_count != 0) { 556 local_mem_free_count = mem_free_count; 557 } 558 mem_free_count = 0; 559#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 560 561 if ((!mem->used) && (mem->next - (ptr + SIZEOF_STRUCT_MEM)) >= size) { 562 /* mem is not used and at least perfect fit is possible: 563 * mem->next - (ptr + SIZEOF_STRUCT_MEM) gives us the 'user data size' of mem */ 564 565 if (mem->next - (ptr + SIZEOF_STRUCT_MEM) >= 566 (size + SIZEOF_STRUCT_MEM + MIN_SIZE_ALIGNED)) { 567 /* (in addition to the above, we test if another struct mem (SIZEOF_STRUCT_MEM) containing 568 * at least MIN_SIZE_ALIGNED of data also fits in the 'user data space' of 'mem') 569 * -> split large block, create empty remainder, 570 * remainder must be large enough to contain MIN_SIZE_ALIGNED data: if 571 * mem->next - (ptr + (2*SIZEOF_STRUCT_MEM)) == size, 572 * struct mem would fit in but no data between mem2 and mem2->next 573 * @todo we could leave out MIN_SIZE_ALIGNED. We would create an empty 574 * region that couldn't hold data, but when mem->next gets freed, 575 * the 2 regions would be combined, resulting in more free memory 576 */ 577 ptr2 = ptr + SIZEOF_STRUCT_MEM + size; 578 /* create mem2 struct */ 579 mem2 = (struct mem *) &ram[ptr2]; 580 mem2->used = 0; 581 mem2->next = mem->next; 582 mem2->prev = ptr; 583 /* and insert it between mem and mem->next */ 584 mem->next = ptr2; 585 mem->used = 1; 586 587 if (mem2->next != MEM_SIZE_ALIGNED) { 588 ((struct mem *) &ram[mem2->next])->prev = ptr2; 589 } 590 MEM_STATS_INC_USED(used, (size + SIZEOF_STRUCT_MEM)); 591 } else { 592 /* (a mem2 struct does no fit into the user data space of mem and mem->next will always 593 * be used at this point: if not we have 2 unused structs in a row, plug_holes should have 594 * take care of this). 595 * -> near fit or excact fit: do not split, no mem2 creation 596 * also can't move mem->next directly behind mem, since mem->next 597 * will always be used at this point! 598 */ 599 mem->used = 1; 600 MEM_STATS_INC_USED(used, mem->next - ((u8_t *) mem - ram)); 601 } 602 603 if (mem == lfree) { 604 /* Find next free block after mem and update lowest free pointer */ 605 while (lfree->used && lfree != ram_end) { 606 LWIP_MEM_ALLOC_UNPROTECT(); 607 /* prevent high interrupt latency... */ 608 LWIP_MEM_ALLOC_PROTECT(); 609 lfree = (struct mem *) &ram[lfree->next]; 610 } 611 LWIP_ASSERT("mem_malloc: !lfree->used", 612 ((lfree == ram_end) || (!lfree->used))); 613 } 614 LWIP_MEM_ALLOC_UNPROTECT(); 615 sys_sem_signal(mem_sem); 616 LWIP_ASSERT("mem_malloc: allocated memory not above ram_end.", 617 (mem_ptr_t) mem + SIZEOF_STRUCT_MEM + size <= 618 (mem_ptr_t) ram_end); 619 LWIP_ASSERT("mem_malloc: allocated memory properly aligned.", 620 ((mem_ptr_t) mem + 621 SIZEOF_STRUCT_MEM) % MEM_ALIGNMENT == 0); 622 LWIP_ASSERT("mem_malloc: sanity check alignment", 623 (((mem_ptr_t) mem) & (MEM_ALIGNMENT - 1)) == 0); 624 625 return (u8_t *) mem + SIZEOF_STRUCT_MEM; 626 } 627 } 628#if LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT 629 /* if we got interrupted by a mem_free, try again */ 630 } while (local_mem_free_count != 0); 631#endif /* LWIP_ALLOW_MEM_FREE_FROM_OTHER_CONTEXT */ 632 LWIP_DEBUGF(MEM_DEBUG | 2, 633 ("mem_malloc: could not allocate %" S16_F " bytes\n", 634 (s16_t) size)); 635 MEM_STATS_INC(err); 636 LWIP_MEM_ALLOC_UNPROTECT(); 637 sys_sem_signal(mem_sem); 638 return NULL; 639} 640 641#endif /* MEM_USE_POOLS */ 642/** 643 * Contiguously allocates enough space for count objects that are size bytes 644 * of memory each and returns a pointer to the allocated memory. 645 * 646 * The allocated memory is filled with bytes of value zero. 647 * 648 * @param count number of objects to allocate 649 * @param size size of the objects to allocate 650 * @return pointer to allocated memory / NULL pointer if there is an error 651 */ 652void *mem_calloc(mem_size_t count, mem_size_t size) 653{ 654 655 void *p; 656 657 /* allocate 'count' objects of size 'size' */ 658 p = mem_malloc(count * size); 659 if (p) { 660 /* zero the memory */ 661 memset(p, 0, count * size); 662 } 663 return p; 664} 665 666#endif /* !MEM_LIBC_MALLOC */ 667