1 /* 2 3 B G E T 4 5 Buffer allocator 6 7 Designed and implemented in April of 1972 by John Walker, based on the 8 Case Algol OPRO$ algorithm implemented in 1966. 9 10 Reimplemented in 1975 by John Walker for the Interdata 70. 11 Reimplemented in 1977 by John Walker for the Marinchip 9900. 12 Reimplemented in 1982 by Duff Kurland for the Intel 8080. 13 14 Portable C version implemented in September of 1990 by an older, wiser 15 instance of the original implementor. 16 17 Souped up and/or weighed down slightly shortly thereafter by Greg 18 Lutz. 19 20 AMIX edition, including the new compaction call-back option, prepared 21 by John Walker in July of 1992. 22 23 Bug in built-in test program fixed, ANSI compiler warnings eradicated, 24 buffer pool validator implemented, and guaranteed repeatable test 25 added by John Walker in October of 1995. 26 27 This program is in the public domain. 28 29 1. This is the book of the generations of Adam. In the day that God 30 created man, in the likeness of God made he him; 31 2. Male and female created he them; and blessed them, and called 32 their name Adam, in the day when they were created. 33 3. And Adam lived an hundred and thirty years, and begat a son in 34 his own likeness, and after his image; and called his name Seth: 35 4. And the days of Adam after he had begotten Seth were eight 36 hundred years: and he begat sons and daughters: 37 5. And all the days that Adam lived were nine hundred and thirty 38 years: and he died. 39 6. And Seth lived an hundred and five years, and begat Enos: 40 7. And Seth lived after he begat Enos eight hundred and seven years, 41 and begat sons and daughters: 42 8. And all the days of Seth were nine hundred and twelve years: and 43 he died. 44 9. And Enos lived ninety years, and begat Cainan: 45 10. And Enos lived after he begat Cainan eight hundred and fifteen 46 years, and begat sons and daughters: 47 11. And all the days of Enos were nine hundred and five years: and 48 he died. 49 12. And Cainan lived seventy years and begat Mahalaleel: 50 13. And Cainan lived after he begat Mahalaleel eight hundred and 51 forty years, and begat sons and daughters: 52 14. And all the days of Cainan were nine hundred and ten years: and 53 he died. 54 15. And Mahalaleel lived sixty and five years, and begat Jared: 55 16. And Mahalaleel lived after he begat Jared eight hundred and 56 thirty years, and begat sons and daughters: 57 17. And all the days of Mahalaleel were eight hundred ninety and 58 five years: and he died. 59 18. And Jared lived an hundred sixty and two years, and he begat 60 Enoch: 61 19. And Jared lived after he begat Enoch eight hundred years, and 62 begat sons and daughters: 63 20. And all the days of Jared were nine hundred sixty and two years: 64 and he died. 65 21. And Enoch lived sixty and five years, and begat Methuselah: 66 22. And Enoch walked with God after he begat Methuselah three 67 hundred years, and begat sons and daughters: 68 23. And all the days of Enoch were three hundred sixty and five 69 years: 70 24. And Enoch walked with God: and he was not; for God took him. 71 25. And Methuselah lived an hundred eighty and seven years, and 72 begat Lamech. 73 26. And Methuselah lived after he begat Lamech seven hundred eighty 74 and two years, and begat sons and daughters: 75 27. And all the days of Methuselah were nine hundred sixty and nine 76 years: and he died. 77 28. And Lamech lived an hundred eighty and two years, and begat a 78 son: 79 29. And he called his name Noah, saying, This same shall comfort us 80 concerning our work and toil of our hands, because of the ground 81 which the LORD hath cursed. 82 30. And Lamech lived after he begat Noah five hundred ninety and 83 five years, and begat sons and daughters: 84 31. And all the days of Lamech were seven hundred seventy and seven 85 years: and he died. 86 32. And Noah was five hundred years old: and Noah begat Shem, Ham, 87 and Japheth. 88 89 And buffers begat buffers, and links begat links, and buffer pools 90 begat links to chains of buffer pools containing buffers, and lo the 91 buffers and links and pools of buffers and pools of links to chains of 92 pools of buffers were fruitful and they multiplied and the Operating 93 System looked down upon them and said that it was Good. 94 95 96 INTRODUCTION 97 ============ 98 99 BGET is a comprehensive memory allocation package which is easily 100 configured to the needs of an application. BGET is efficient in 101 both the time needed to allocate and release buffers and in the 102 memory overhead required for buffer pool management. It 103 automatically consolidates contiguous space to minimise 104 fragmentation. BGET is configured by compile-time definitions, 105 Major options include: 106 107 * A built-in test program to exercise BGET and 108 demonstrate how the various functions are used. 109 110 * Allocation by either the "first fit" or "best fit" 111 method. 112 113 * Wiping buffers at release time to catch code which 114 references previously released storage. 115 116 * Built-in routines to dump individual buffers or the 117 entire buffer pool. 118 119 * Retrieval of allocation and pool size statistics. 120 121 * Quantisation of buffer sizes to a power of two to 122 satisfy hardware alignment constraints. 123 124 * Automatic pool compaction, growth, and shrinkage by 125 means of call-backs to user defined functions. 126 127 Applications of BGET can range from storage management in 128 ROM-based embedded programs to providing the framework upon which 129 a multitasking system incorporating garbage collection is 130 constructed. BGET incorporates extensive internal consistency 131 checking using the <assert.h> mechanism; all these checks can be 132 turned off by compiling with NDEBUG defined, yielding a version of 133 BGET with minimal size and maximum speed. 134 135 The basic algorithm underlying BGET has withstood the test of 136 time; more than 25 years have passed since the first 137 implementation of this code. And yet, it is substantially more 138 efficient than the native allocation schemes of many operating 139 systems: the Macintosh and Microsoft Windows to name two, on which 140 programs have obtained substantial speed-ups by layering BGET as 141 an application level memory manager atop the underlying system's. 142 143 BGET has been implemented on the largest mainframes and the lowest 144 of microprocessors. It has served as the core for multitasking 145 operating systems, multi-thread applications, embedded software in 146 data network switching processors, and a host of C programs. And 147 while it has accreted flexibility and additional options over the 148 years, it remains fast, memory efficient, portable, and easy to 149 integrate into your program. 150 151 152 BGET IMPLEMENTATION ASSUMPTIONS 153 =============================== 154 155 BGET is written in as portable a dialect of C as possible. The 156 only fundamental assumption about the underlying hardware 157 architecture is that memory is allocated is a linear array which 158 can be addressed as a vector of C "char" objects. On segmented 159 address space architectures, this generally means that BGET should 160 be used to allocate storage within a single segment (although some 161 compilers simulate linear address spaces on segmented 162 architectures). On segmented architectures, then, BGET buffer 163 pools may not be larger than a segment, but since BGET allows any 164 number of separate buffer pools, there is no limit on the total 165 storage which can be managed, only on the largest individual 166 object which can be allocated. Machines with a linear address 167 architecture, such as the VAX, 680x0, Sparc, MIPS, or the Intel 168 80386 and above in native mode, may use BGET without restriction. 169 170 171 GETTING STARTED WITH BGET 172 ========================= 173 174 Although BGET can be configured in a multitude of fashions, there 175 are three basic ways of working with BGET. The functions 176 mentioned below are documented in the following section. Please 177 excuse the forward references which are made in the interest of 178 providing a roadmap to guide you to the BGET functions you're 179 likely to need. 180 181 Embedded Applications 182 --------------------- 183 184 Embedded applications typically have a fixed area of memory 185 dedicated to buffer allocation (often in a separate RAM address 186 space distinct from the ROM that contains the executable code). 187 To use BGET in such an environment, simply call bpool() with the 188 start address and length of the buffer pool area in RAM, then 189 allocate buffers with bget() and release them with brel(). 190 Embedded applications with very limited RAM but abundant CPU speed 191 may benefit by configuring BGET for BestFit allocation (which is 192 usually not worth it in other environments). 193 194 Malloc() Emulation 195 ------------------ 196 197 If the C library malloc() function is too slow, not present in 198 your development environment (for example, an a native Windows or 199 Macintosh program), or otherwise unsuitable, you can replace it 200 with BGET. Initially define a buffer pool of an appropriate size 201 with bpool()--usually obtained by making a call to the operating 202 system's low-level memory allocator. Then allocate buffers with 203 bget(), bgetz(), and bgetr() (the last two permit the allocation 204 of buffers initialised to zero and [inefficient] re-allocation of 205 existing buffers for compatibility with C library functions). 206 Release buffers by calling brel(). If a buffer allocation request 207 fails, obtain more storage from the underlying operating system, 208 add it to the buffer pool by another call to bpool(), and continue 209 execution. 210 211 Automatic Storage Management 212 ---------------------------- 213 214 You can use BGET as your application's native memory manager and 215 implement automatic storage pool expansion, contraction, and 216 optionally application-specific memory compaction by compiling 217 BGET with the BECtl variable defined, then calling bectl() and 218 supplying functions for storage compaction, acquisition, and 219 release, as well as a standard pool expansion increment. All of 220 these functions are optional (although it doesn't make much sense 221 to provide a release function without an acquisition function, 222 does it?). Once the call-back functions have been defined with 223 bectl(), you simply use bget() and brel() to allocate and release 224 storage as before. You can supply an initial buffer pool with 225 bpool() or rely on automatic allocation to acquire the entire 226 pool. When a call on bget() cannot be satisfied, BGET first 227 checks if a compaction function has been supplied. If so, it is 228 called (with the space required to satisfy the allocation request 229 and a sequence number to allow the compaction routine to be called 230 successively without looping). If the compaction function is able 231 to free any storage (it needn't know whether the storage it freed 232 was adequate) it should return a nonzero value, whereupon BGET 233 will retry the allocation request and, if it fails again, call the 234 compaction function again with the next-higher sequence number. 235 236 If the compaction function returns zero, indicating failure to 237 free space, or no compaction function is defined, BGET next tests 238 whether a non-NULL allocation function was supplied to bectl(). 239 If so, that function is called with an argument indicating how 240 many bytes of additional space are required. This will be the 241 standard pool expansion increment supplied in the call to bectl() 242 unless the original bget() call requested a buffer larger than 243 this; buffers larger than the standard pool block can be managed 244 "off the books" by BGET in this mode. If the allocation function 245 succeeds in obtaining the storage, it returns a pointer to the new 246 block and BGET expands the buffer pool; if it fails, the 247 allocation request fails and returns NULL to the caller. If a 248 non-NULL release function is supplied, expansion blocks which 249 become totally empty are released to the global free pool by 250 passing their addresses to the release function. 251 252 Equipped with appropriate allocation, release, and compaction 253 functions, BGET can be used as part of very sophisticated memory 254 management strategies, including garbage collection. (Note, 255 however, that BGET is *not* a garbage collector by itself, and 256 that developing such a system requires much additional logic and 257 careful design of the application's memory allocation strategy.) 258 259 260 BGET FUNCTION DESCRIPTIONS 261 ========================== 262 263 Functions implemented in this file (some are enabled by certain of 264 the optional settings below): 265 266 void bpool(void *buffer, bufsize len); 267 268 Create a buffer pool of <len> bytes, using the storage starting at 269 <buffer>. You can call bpool() subsequently to contribute 270 additional storage to the overall buffer pool. 271 272 void *bget(bufsize size); 273 274 Allocate a buffer of <size> bytes. The address of the buffer is 275 returned, or NULL if insufficient memory was available to allocate 276 the buffer. 277 278 void *bgetz(bufsize size); 279 280 Allocate a buffer of <size> bytes and clear it to all zeroes. The 281 address of the buffer is returned, or NULL if insufficient memory 282 was available to allocate the buffer. 283 284 void *bgetr(void *buffer, bufsize newsize); 285 286 Reallocate a buffer previously allocated by bget(), changing its 287 size to <newsize> and preserving all existing data. NULL is 288 returned if insufficient memory is available to reallocate the 289 buffer, in which case the original buffer remains intact. 290 291 void brel(void *buf); 292 293 Return the buffer <buf>, previously allocated by bget(), to the 294 free space pool. 295 296 void bectl(int (*compact)(bufsize sizereq, int sequence), 297 void *(*acquire)(bufsize size), 298 void (*release)(void *buf), 299 bufsize pool_incr); 300 301 Expansion control: specify functions through which the package may 302 compact storage (or take other appropriate action) when an 303 allocation request fails, and optionally automatically acquire 304 storage for expansion blocks when necessary, and release such 305 blocks when they become empty. If <compact> is non-NULL, whenever 306 a buffer allocation request fails, the <compact> function will be 307 called with arguments specifying the number of bytes (total buffer 308 size, including header overhead) required to satisfy the 309 allocation request, and a sequence number indicating the number of 310 consecutive calls on <compact> attempting to satisfy this 311 allocation request. The sequence number is 1 for the first call 312 on <compact> for a given allocation request, and increments on 313 subsequent calls, permitting the <compact> function to take 314 increasingly dire measures in an attempt to free up storage. If 315 the <compact> function returns a nonzero value, the allocation 316 attempt is re-tried. If <compact> returns 0 (as it must if it 317 isn't able to release any space or add storage to the buffer 318 pool), the allocation request fails, which can trigger automatic 319 pool expansion if the <acquire> argument is non-NULL. At the time 320 the <compact> function is called, the state of the buffer 321 allocator is identical to that at the moment the allocation 322 request was made; consequently, the <compact> function may call 323 brel(), bpool(), bstats(), and/or directly manipulate the buffer 324 pool in any manner which would be valid were the application in 325 control. This does not, however, relieve the <compact> function 326 of the need to ensure that whatever actions it takes do not change 327 things underneath the application that made the allocation 328 request. For example, a <compact> function that released a buffer 329 in the process of being reallocated with bgetr() would lead to 330 disaster. Implementing a safe and effective <compact> mechanism 331 requires careful design of an application's memory architecture, 332 and cannot generally be easily retrofitted into existing code. 333 334 If <acquire> is non-NULL, that function will be called whenever an 335 allocation request fails. If the <acquire> function succeeds in 336 allocating the requested space and returns a pointer to the new 337 area, allocation will proceed using the expanded buffer pool. If 338 <acquire> cannot obtain the requested space, it should return NULL 339 and the entire allocation process will fail. <pool_incr> 340 specifies the normal expansion block size. Providing an <acquire> 341 function will cause subsequent bget() requests for buffers too 342 large to be managed in the linked-block scheme (in other words, 343 larger than <pool_incr> minus the buffer overhead) to be satisfied 344 directly by calls to the <acquire> function. Automatic release of 345 empty pool blocks will occur only if all pool blocks in the system 346 are the size given by <pool_incr>. 347 348 void bstats(bufsize *curalloc, bufsize *totfree, 349 bufsize *maxfree, long *nget, long *nrel); 350 351 The amount of space currently allocated is stored into the 352 variable pointed to by <curalloc>. The total free space (sum of 353 all free blocks in the pool) is stored into the variable pointed 354 to by <totfree>, and the size of the largest single block in the 355 free space pool is stored into the variable pointed to by 356 <maxfree>. The variables pointed to by <nget> and <nrel> are 357 filled, respectively, with the number of successful (non-NULL 358 return) bget() calls and the number of brel() calls. 359 360 void bstatse(bufsize *pool_incr, long *npool, 361 long *npget, long *nprel, 362 long *ndget, long *ndrel); 363 364 Extended statistics: The expansion block size will be stored into 365 the variable pointed to by <pool_incr>, or the negative thereof if 366 automatic expansion block releases are disabled. The number of 367 currently active pool blocks will be stored into the variable 368 pointed to by <npool>. The variables pointed to by <npget> and 369 <nprel> will be filled with, respectively, the number of expansion 370 block acquisitions and releases which have occurred. The 371 variables pointed to by <ndget> and <ndrel> will be filled with 372 the number of bget() and brel() calls, respectively, managed 373 through blocks directly allocated by the acquisition and release 374 functions. 375 376 void bufdump(void *buf); 377 378 The buffer pointed to by <buf> is dumped on standard output. 379 380 void bpoold(void *pool, int dumpalloc, int dumpfree); 381 382 All buffers in the buffer pool <pool>, previously initialised by a 383 call on bpool(), are listed in ascending memory address order. If 384 <dumpalloc> is nonzero, the contents of allocated buffers are 385 dumped; if <dumpfree> is nonzero, the contents of free blocks are 386 dumped. 387 388 int bpoolv(void *pool); 389 390 The named buffer pool, previously initialised by a call on 391 bpool(), is validated for bad pointers, overwritten data, etc. If 392 compiled with NDEBUG not defined, any error generates an assertion 393 failure. Otherwise 1 is returned if the pool is valid, 0 if an 394 error is found. 395 396 397 BGET CONFIGURATION 398 ================== 399 */ 400 401 /* 402 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED 403 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 404 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 405 * IN NO EVENT SHALL ST BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 406 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 407 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 408 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 409 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 410 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 411 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 412 */ 413 414 /* #define BGET_ENABLE_ALL_OPTIONS */ 415 #ifdef BGET_ENABLE_OPTION 416 #define TestProg 20000 /* Generate built-in test program 417 if defined. The value specifies 418 how many buffer allocation attempts 419 the test program should make. */ 420 421 #define SizeQuant 4 /* Buffer allocation size quantum: 422 all buffers allocated are a 423 multiple of this size. This 424 MUST be a power of two. */ 425 426 #define BufDump 1 /* Define this symbol to enable the 427 bpoold() function which dumps the 428 buffers in a buffer pool. */ 429 430 #define BufValid 1 /* Define this symbol to enable the 431 bpoolv() function for validating 432 a buffer pool. */ 433 434 #define DumpData 1 /* Define this symbol to enable the 435 bufdump() function which allows 436 dumping the contents of an allocated 437 or free buffer. */ 438 439 #define BufStats 1 /* Define this symbol to enable the 440 bstats() function which calculates 441 the total free space in the buffer 442 pool, the largest available 443 buffer, and the total space 444 currently allocated. */ 445 446 #define FreeWipe 1 /* Wipe free buffers to a guaranteed 447 pattern of garbage to trip up 448 miscreants who attempt to use 449 pointers into released buffers. */ 450 451 #define BestFit 1 /* Use a best fit algorithm when 452 searching for space for an 453 allocation request. This uses 454 memory more efficiently, but 455 allocation will be much slower. */ 456 457 #define BECtl 1 /* Define this symbol to enable the 458 bectl() function for automatic 459 pool space control. */ 460 #endif 461 462 #include <stdio.h> 463 #include <stdbool.h> 464 465 #ifdef lint 466 #define NDEBUG /* Exits in asserts confuse lint */ 467 /* LINTLIBRARY */ /* Don't complain about def, no ref */ 468 extern char *sprintf(); /* Sun includes don't define sprintf */ 469 #endif 470 471 #include <assert.h> 472 #include <memory.h> 473 474 #ifdef BufDump /* BufDump implies DumpData */ 475 #ifndef DumpData 476 #define DumpData 1 477 #endif 478 #endif 479 480 #ifdef DumpData 481 #include <ctype.h> 482 #endif 483 484 #ifdef __KERNEL__ 485 #ifdef CFG_CORE_BGET_BESTFIT 486 #define BestFit 1 487 #endif 488 #endif 489 490 /* Declare the interface, including the requested buffer size type, 491 bufsize. */ 492 493 #include "bget.h" 494 495 #define MemSize int /* Type for size arguments to memxxx() 496 functions such as memcmp(). */ 497 498 /* Queue links */ 499 500 struct qlinks { 501 struct bfhead *flink; /* Forward link */ 502 struct bfhead *blink; /* Backward link */ 503 }; 504 505 /* Header in allocated and free buffers */ 506 507 struct bhead { 508 bufsize prevfree; /* Relative link back to previous 509 free buffer in memory or 0 if 510 previous buffer is allocated. */ 511 bufsize bsize; /* Buffer size: positive if free, 512 negative if allocated. */ 513 }; 514 #define BH(p) ((struct bhead *) (p)) 515 516 /* Header in directly allocated buffers (by acqfcn) */ 517 518 struct bdhead { 519 bufsize tsize; /* Total size, including overhead */ 520 bufsize offs; /* Offset from allocated buffer */ 521 struct bhead bh; /* Common header */ 522 }; 523 #define BDH(p) ((struct bdhead *) (p)) 524 525 /* Header in free buffers */ 526 527 struct bfhead { 528 struct bhead bh; /* Common allocated/free header */ 529 struct qlinks ql; /* Links on free list */ 530 }; 531 #define BFH(p) ((struct bfhead *) (p)) 532 533 /* Poolset definition */ 534 struct bpoolset { 535 struct bfhead freelist; 536 #ifdef BufStats 537 bufsize totalloc; /* Total space currently allocated */ 538 long numget; /* Number of bget() calls */ 539 long numrel; /* Number of brel() calls */ 540 #ifdef BECtl 541 long numpblk; /* Number of pool blocks */ 542 long numpget; /* Number of block gets and rels */ 543 long numprel; 544 long numdget; /* Number of direct gets and rels */ 545 long numdrel; 546 #endif /* BECtl */ 547 #endif /* BufStats */ 548 549 #ifdef BECtl 550 /* Automatic expansion block management functions */ 551 552 int (*compfcn) _((bufsize sizereq, int sequence)); 553 void *(*acqfcn) _((bufsize size)); 554 void (*relfcn) _((void *buf)); 555 556 bufsize exp_incr; /* Expansion block size */ 557 bufsize pool_len; /* 0: no bpool calls have been made 558 -1: not all pool blocks are 559 the same size 560 >0: (common) block size for all 561 bpool calls made so far 562 */ 563 #endif 564 }; 565 566 /* Minimum allocation quantum: */ 567 568 #define QLSize (sizeof(struct qlinks)) 569 #define SizeQ ((SizeQuant > QLSize) ? SizeQuant : QLSize) 570 571 #define V (void) /* To denote unwanted returned values */ 572 573 /* End sentinel: value placed in bsize field of dummy block delimiting 574 end of pool block. The most negative number which will fit in a 575 bufsize, defined in a way that the compiler will accept. */ 576 577 #define ESent ((bufsize) (-(((1L << (sizeof(bufsize) * 8 - 2)) - 1) * 2) - 2)) 578 579 static bufsize buf_get_pos(struct bfhead *bf, bufsize align, bufsize hdr_size, 580 bufsize size) 581 { 582 unsigned long buf = 0; 583 bufsize pos = 0; 584 585 if (bf->bh.bsize < size) 586 return -1; 587 588 /* 589 * plus sizeof(struct bhead) and hdr_size since buf will follow just 590 * after a struct bhead and an eventual extra header. 591 */ 592 buf = (unsigned long)bf + bf->bh.bsize - size + sizeof(struct bhead) + 593 hdr_size; 594 buf &= ~(align - 1); 595 pos = buf - (unsigned long)bf - sizeof(struct bhead) - hdr_size; 596 597 if (pos == 0) /* exact match */ 598 return pos; 599 if (pos >= SizeQ + sizeof(struct bhead)) /* room for an empty buffer */ 600 return pos; 601 602 return -1; 603 } 604 605 /* BGET -- Allocate a buffer. */ 606 607 void *bget(requested_align, hdr_size, requested_size, poolset) 608 bufsize requested_align; 609 bufsize hdr_size; 610 bufsize requested_size; 611 struct bpoolset *poolset; 612 { 613 bufsize align = requested_align; 614 bufsize size = requested_size; 615 bufsize pos; 616 struct bfhead *b; 617 #ifdef BestFit 618 struct bfhead *best; 619 #endif 620 void *buf; 621 #ifdef BECtl 622 int compactseq = 0; 623 #endif 624 625 assert(size > 0); 626 COMPILE_TIME_ASSERT(BGET_HDR_QUANTUM == SizeQ); 627 628 if (align < 0 || (align > 0 && !IS_POWER_OF_TWO((unsigned long)align))) 629 return NULL; 630 if (hdr_size % BGET_HDR_QUANTUM != 0) 631 return NULL; 632 633 if (size < SizeQ) { /* Need at least room for the */ 634 size = SizeQ; /* queue links. */ 635 } 636 if (align < SizeQ) 637 align = SizeQ; 638 #ifdef SizeQuant 639 #if SizeQuant > 1 640 if (ADD_OVERFLOW(size, SizeQuant - 1, &size)) 641 return NULL; 642 643 size = ROUNDDOWN(size, SizeQuant); 644 #endif 645 #endif 646 647 /* Add overhead in allocated buffer to size required. */ 648 if (ADD_OVERFLOW(size, sizeof(struct bhead), &size)) 649 return NULL; 650 if (ADD_OVERFLOW(size, hdr_size, &size)) 651 return NULL; 652 653 #ifdef BECtl 654 /* If a compact function was provided in the call to bectl(), wrap 655 a loop around the allocation process to allow compaction to 656 intervene in case we don't find a suitable buffer in the chain. */ 657 658 while (1) { 659 #endif 660 b = poolset->freelist.ql.flink; 661 #ifdef BestFit 662 best = &poolset->freelist; 663 #endif 664 665 666 /* Scan the free list searching for the first buffer big enough 667 to hold the requested size buffer. */ 668 669 #ifdef BestFit 670 while (b != &poolset->freelist) { 671 assert(b->bh.prevfree == 0); 672 pos = buf_get_pos(b, align, hdr_size, size); 673 if (pos >= 0) { 674 if ((best == &poolset->freelist) || 675 (b->bh.bsize < best->bh.bsize)) { 676 best = b; 677 } 678 } 679 b = b->ql.flink; /* Link to next buffer */ 680 } 681 b = best; 682 #endif /* BestFit */ 683 684 while (b != &poolset->freelist) { 685 pos = buf_get_pos(b, align, hdr_size, size); 686 if (pos >= 0) { 687 struct bhead *b_alloc = BH((char *)b + pos); 688 struct bhead *b_next = BH((char *)b + b->bh.bsize); 689 690 assert(b_next->prevfree == b->bh.bsize); 691 692 /* 693 * Zero the back pointer in the next buffer in memory 694 * to indicate that this buffer is allocated. 695 */ 696 b_next->prevfree = 0; 697 698 assert(b->ql.blink->ql.flink == b); 699 assert(b->ql.flink->ql.blink == b); 700 701 if (pos == 0) { 702 /* 703 * Need to allocate from the beginning of this free block. 704 * Unlink the block and mark it as allocated. 705 */ 706 b->ql.blink->ql.flink = b->ql.flink; 707 b->ql.flink->ql.blink = b->ql.blink; 708 709 /* Negate size to mark buffer allocated. */ 710 b->bh.bsize = -b->bh.bsize; 711 } else { 712 /* 713 * Carve out the memory allocation from the end of this 714 * free block. Negative size to mark buffer allocated. 715 */ 716 b_alloc->bsize = -(b->bh.bsize - pos); 717 b_alloc->prevfree = pos; 718 b->bh.bsize = pos; 719 } 720 721 assert(b_alloc->bsize < 0); 722 /* 723 * At this point is b_alloc pointing to the allocated 724 * buffer and b_next at the buffer following. b might be a 725 * free block or a used block now. 726 */ 727 if (-b_alloc->bsize - size > SizeQ + sizeof(struct bhead)) { 728 /* 729 * b_alloc has too much unused memory at the 730 * end we need to split the block and register that 731 * last part as free. 732 */ 733 b = BFH((char *)b_alloc + size); 734 b->bh.bsize = -b_alloc->bsize - size; 735 b->bh.prevfree = 0; 736 b_alloc->bsize += b->bh.bsize; 737 738 assert(poolset->freelist.ql.blink->ql.flink == 739 &poolset->freelist); 740 assert(poolset->freelist.ql.flink->ql.blink == 741 &poolset->freelist); 742 b->ql.flink = &poolset->freelist; 743 b->ql.blink = poolset->freelist.ql.blink; 744 poolset->freelist.ql.blink = b; 745 b->ql.blink->ql.flink = b; 746 747 assert(BH((char *)b + b->bh.bsize) == b_next); 748 b_next->prevfree = b->bh.bsize; 749 } 750 751 #ifdef BufStats 752 poolset->totalloc -= b_alloc->bsize; 753 poolset->numget++; /* Increment number of bget() calls */ 754 #endif 755 buf = (char *)b_alloc + sizeof(struct bhead); 756 return buf; 757 } 758 b = b->ql.flink; /* Link to next buffer */ 759 } 760 #ifdef BECtl 761 762 /* We failed to find a buffer. If there's a compact function 763 defined, notify it of the size requested. If it returns 764 TRUE, try the allocation again. */ 765 766 if ((poolset->compfcn == NULL) || 767 (!(poolset->compfcn)(size, ++compactseq))) { 768 break; 769 } 770 } 771 772 /* No buffer available with requested size free. */ 773 774 /* Don't give up yet -- look in the reserve supply. */ 775 776 if (poolset->acqfcn != NULL) { 777 if (size > exp_incr - sizeof(struct bfhead) - align) { 778 779 /* Request is too large to fit in a single expansion 780 block. Try to satisy it by a direct buffer acquisition. */ 781 char *p; 782 783 size += sizeof(struct bdhead) - sizeof(struct bhead); 784 if (align > QLSize) 785 size += align; 786 p = poolset->acqfcn(size); 787 if (p != NULL) { 788 struct bdhead *bdh; 789 790 if (align <= QLSize) { 791 bdh = BDH(p); 792 buf = bdh + 1; 793 } else { 794 unsigned long tp = (unsigned long)p; 795 796 tp += sizeof(*bdh) + hdr_size + align; 797 tp &= ~(align - 1); 798 tp -= hdr_size; 799 buf = (void *)tp; 800 bdh = BDH((char *)buf - sizeof(*bdh)); 801 } 802 803 /* Mark the buffer special by setting the size field 804 of its header to zero. */ 805 bdh->bh.bsize = 0; 806 bdh->bh.prevfree = 0; 807 bdh->tsize = size; 808 bdh->offs = (unsigned long)bdh - (unsigned long)p; 809 #ifdef BufStats 810 poolset->totalloc += size; 811 poolset->numget++; /* Increment number of bget() calls */ 812 poolset->numdget++; /* Direct bget() call count */ 813 #endif 814 return buf; 815 } 816 817 } else { 818 819 /* Try to obtain a new expansion block */ 820 821 void *newpool; 822 823 if ((newpool = poolset->acqfcn((bufsize) exp_incr)) != NULL) { 824 bpool(newpool, exp_incr, poolset); 825 buf = bget(align, hdr_size, requested_size, pool); /* This can't, I say, can't 826 get into a loop. */ 827 return buf; 828 } 829 } 830 } 831 832 /* Still no buffer available */ 833 834 #endif /* BECtl */ 835 836 return NULL; 837 } 838 839 /* BGETZ -- Allocate a buffer and clear its contents to zero. We clear 840 the entire contents of the buffer to zero, not just the 841 region requested by the caller. */ 842 843 void *bgetz(align, hdr_size, size, poolset) 844 bufsize align; 845 bufsize hdr_size; 846 bufsize size; 847 struct bpoolset *poolset; 848 { 849 char *buf = (char *) bget(align, hdr_size, size, poolset); 850 851 if (buf != NULL) { 852 struct bhead *b; 853 bufsize rsize; 854 855 b = BH(buf - sizeof(struct bhead)); 856 rsize = -(b->bsize); 857 if (rsize == 0) { 858 struct bdhead *bd; 859 860 bd = BDH(buf - sizeof(struct bdhead)); 861 rsize = bd->tsize - sizeof(struct bdhead) - bd->offs; 862 } else { 863 rsize -= sizeof(struct bhead); 864 } 865 assert(rsize >= size); 866 V memset_unchecked(buf, 0, (MemSize) rsize); 867 } 868 return ((void *) buf); 869 } 870 871 /* BGETR -- Reallocate a buffer. This is a minimal implementation, 872 simply in terms of brel() and bget(). It could be 873 enhanced to allow the buffer to grow into adjacent free 874 blocks and to avoid moving data unnecessarily. */ 875 876 void *bgetr(buf, align, hdr_size, size, poolset) 877 void *buf; 878 bufsize align; 879 bufsize hdr_size; 880 bufsize size; 881 struct bpoolset *poolset; 882 { 883 void *nbuf; 884 bufsize osize; /* Old size of buffer */ 885 struct bhead *b; 886 887 if ((nbuf = bget(align, hdr_size, size, poolset)) == NULL) { /* Acquire new buffer */ 888 return NULL; 889 } 890 if (buf == NULL) { 891 return nbuf; 892 } 893 b = BH(((char *) buf) - sizeof(struct bhead)); 894 osize = -b->bsize; 895 #ifdef BECtl 896 if (osize == 0) { 897 /* Buffer acquired directly through acqfcn. */ 898 struct bdhead *bd; 899 900 bd = BDH(((char *) buf) - sizeof(struct bdhead)); 901 osize = bd->tsize - sizeof(struct bdhead) - bd->offs; 902 } else 903 #endif 904 osize -= sizeof(struct bhead); 905 assert(osize > 0); 906 V memcpy_unchecked((char *) nbuf, (char *) buf, /* Copy the data */ 907 (MemSize) ((size < osize) ? size : osize)); 908 #ifndef __KERNEL__ 909 /* User space reallocations are always zeroed */ 910 if (size > osize) 911 V memset_unchecked((char *) nbuf + osize, 0, size - osize); 912 #endif 913 brel(buf, poolset, false /* !wipe */); 914 return nbuf; 915 } 916 917 /* BREL -- Release a buffer. */ 918 919 void brel(buf, poolset, wipe) 920 void *buf; 921 struct bpoolset *poolset; 922 int wipe; 923 { 924 struct bfhead *b, *bn; 925 char *wipe_start; 926 bufsize wipe_size; 927 928 b = BFH(((char *) buf) - sizeof(struct bhead)); 929 #ifdef BufStats 930 poolset->numrel++; /* Increment number of brel() calls */ 931 #endif 932 assert(buf != NULL); 933 934 #ifdef FreeWipe 935 wipe = true; 936 #endif 937 #ifdef BECtl 938 if (b->bh.bsize == 0) { /* Directly-acquired buffer? */ 939 struct bdhead *bdh; 940 941 bdh = BDH(((char *) buf) - sizeof(struct bdhead)); 942 assert(b->bh.prevfree == 0); 943 #ifdef BufStats 944 poolset->totalloc -= bdh->tsize; 945 assert(poolset->totalloc >= 0); 946 poolset->numdrel++; /* Number of direct releases */ 947 #endif /* BufStats */ 948 if (wipe) { 949 V memset_unchecked((char *) buf, 0x55, 950 (MemSize) (bdh->tsize - 951 sizeof(struct bdhead))); 952 } 953 assert(poolset->relfcn != NULL); 954 poolset->relfcn((char *)buf - sizeof(struct bdhead) - bdh->offs); /* Release it directly. */ 955 return; 956 } 957 #endif /* BECtl */ 958 959 /* Buffer size must be negative, indicating that the buffer is 960 allocated. */ 961 962 if (b->bh.bsize >= 0) { 963 bn = NULL; 964 } 965 assert(b->bh.bsize < 0); 966 967 /* Back pointer in next buffer must be zero, indicating the 968 same thing: */ 969 970 assert(BH((char *) b - b->bh.bsize)->prevfree == 0); 971 972 #ifdef BufStats 973 poolset->totalloc += b->bh.bsize; 974 assert(poolset->totalloc >= 0); 975 #endif 976 977 /* If the back link is nonzero, the previous buffer is free. */ 978 979 if (b->bh.prevfree != 0) { 980 981 /* The previous buffer is free. Consolidate this buffer with it 982 by adding the length of this buffer to the previous free 983 buffer. Note that we subtract the size in the buffer being 984 released, since it's negative to indicate that the buffer is 985 allocated. */ 986 987 register bufsize size = b->bh.bsize; 988 989 /* Only wipe the current buffer, including bfhead. */ 990 wipe_start = (char *)b; 991 wipe_size = -size; 992 993 /* Make the previous buffer the one we're working on. */ 994 assert(BH((char *) b - b->bh.prevfree)->bsize == b->bh.prevfree); 995 b = BFH(((char *) b) - b->bh.prevfree); 996 b->bh.bsize -= size; 997 } else { 998 999 /* The previous buffer isn't allocated. Insert this buffer 1000 on the free list as an isolated free block. */ 1001 1002 assert(poolset->freelist.ql.blink->ql.flink == &poolset->freelist); 1003 assert(poolset->freelist.ql.flink->ql.blink == &poolset->freelist); 1004 b->ql.flink = &poolset->freelist; 1005 b->ql.blink = poolset->freelist.ql.blink; 1006 poolset->freelist.ql.blink = b; 1007 b->ql.blink->ql.flink = b; 1008 b->bh.bsize = -b->bh.bsize; 1009 1010 wipe_start = (char *)b + sizeof(struct bfhead); 1011 wipe_size = b->bh.bsize - sizeof(struct bfhead); 1012 } 1013 1014 /* Now we look at the next buffer in memory, located by advancing from 1015 the start of this buffer by its size, to see if that buffer is 1016 free. If it is, we combine this buffer with the next one in 1017 memory, dechaining the second buffer from the free list. */ 1018 1019 bn = BFH(((char *) b) + b->bh.bsize); 1020 if (bn->bh.bsize > 0) { 1021 1022 /* The buffer is free. Remove it from the free list and add 1023 its size to that of our buffer. */ 1024 1025 assert(BH((char *) bn + bn->bh.bsize)->prevfree == bn->bh.bsize); 1026 assert(bn->ql.blink->ql.flink == bn); 1027 assert(bn->ql.flink->ql.blink == bn); 1028 bn->ql.blink->ql.flink = bn->ql.flink; 1029 bn->ql.flink->ql.blink = bn->ql.blink; 1030 b->bh.bsize += bn->bh.bsize; 1031 1032 /* Finally, advance to the buffer that follows the newly 1033 consolidated free block. We must set its backpointer to the 1034 head of the consolidated free block. We know the next block 1035 must be an allocated block because the process of recombination 1036 guarantees that two free blocks will never be contiguous in 1037 memory. */ 1038 1039 bn = BFH(((char *) b) + b->bh.bsize); 1040 /* Only bfhead of next buffer needs to be wiped */ 1041 wipe_size += sizeof(struct bfhead); 1042 } 1043 if (wipe) { 1044 V memset_unchecked(wipe_start, 0x55, wipe_size); 1045 } 1046 assert(bn->bh.bsize < 0); 1047 1048 /* The next buffer is allocated. Set the backpointer in it to point 1049 to this buffer; the previous free buffer in memory. */ 1050 1051 bn->bh.prevfree = b->bh.bsize; 1052 1053 #ifdef BECtl 1054 1055 /* If a block-release function is defined, and this free buffer 1056 constitutes the entire block, release it. Note that pool_len 1057 is defined in such a way that the test will fail unless all 1058 pool blocks are the same size. */ 1059 1060 if (poolset->relfcn != NULL && 1061 ((bufsize) b->bh.bsize) == (pool_len - sizeof(struct bhead))) { 1062 1063 assert(b->bh.prevfree == 0); 1064 assert(BH((char *) b + b->bh.bsize)->bsize == ESent); 1065 assert(BH((char *) b + b->bh.bsize)->prevfree == b->bh.bsize); 1066 /* Unlink the buffer from the free list */ 1067 b->ql.blink->ql.flink = b->ql.flink; 1068 b->ql.flink->ql.blink = b->ql.blink; 1069 1070 poolset->relfcn(b); 1071 #ifdef BufStats 1072 poolset->numprel++; /* Nr of expansion block releases */ 1073 poolset->numpblk--; /* Total number of blocks */ 1074 assert(numpblk == numpget - numprel); 1075 #endif /* BufStats */ 1076 } 1077 #endif /* BECtl */ 1078 } 1079 1080 #ifdef BECtl 1081 1082 /* BECTL -- Establish automatic pool expansion control */ 1083 1084 void bectl(compact, acquire, release, pool_incr, poolset) 1085 int (*compact) _((bufsize sizereq, int sequence)); 1086 void *(*acquire) _((bufsize size)); 1087 void (*release) _((void *buf)); 1088 bufsize pool_incr; 1089 struct bpoolset *poolset; 1090 { 1091 poolset->compfcn = compact; 1092 poolset->acqfcn = acquire; 1093 poolset->relfcn = release; 1094 poolset->exp_incr = pool_incr; 1095 } 1096 #endif 1097 1098 /* BPOOL -- Add a region of memory to the buffer pool. */ 1099 1100 void bpool(buf, len, poolset) 1101 void *buf; 1102 bufsize len; 1103 struct bpoolset *poolset; 1104 { 1105 struct bfhead *b = BFH(buf); 1106 struct bhead *bn; 1107 1108 #ifdef SizeQuant 1109 len &= ~(SizeQuant - 1); 1110 #endif 1111 #ifdef BECtl 1112 if (poolset->pool_len == 0) { 1113 pool_len = len; 1114 } else if (len != poolset->pool_len) { 1115 poolset->pool_len = -1; 1116 } 1117 #ifdef BufStats 1118 poolset->numpget++; /* Number of block acquisitions */ 1119 poolset->numpblk++; /* Number of blocks total */ 1120 assert(poolset->numpblk == poolset->numpget - poolset->numprel); 1121 #endif /* BufStats */ 1122 #endif /* BECtl */ 1123 1124 /* Since the block is initially occupied by a single free buffer, 1125 it had better not be (much) larger than the largest buffer 1126 whose size we can store in bhead.bsize. */ 1127 1128 assert(len - sizeof(struct bhead) <= -((bufsize) ESent + 1)); 1129 1130 /* Clear the backpointer at the start of the block to indicate that 1131 there is no free block prior to this one. That blocks 1132 recombination when the first block in memory is released. */ 1133 1134 b->bh.prevfree = 0; 1135 1136 /* Chain the new block to the free list. */ 1137 1138 assert(poolset->freelist.ql.blink->ql.flink == &poolset->freelist); 1139 assert(poolset->freelist.ql.flink->ql.blink == &poolset->freelist); 1140 b->ql.flink = &poolset->freelist; 1141 b->ql.blink = poolset->freelist.ql.blink; 1142 poolset->freelist.ql.blink = b; 1143 b->ql.blink->ql.flink = b; 1144 1145 /* Create a dummy allocated buffer at the end of the pool. This dummy 1146 buffer is seen when a buffer at the end of the pool is released and 1147 blocks recombination of the last buffer with the dummy buffer at 1148 the end. The length in the dummy buffer is set to the largest 1149 negative number to denote the end of the pool for diagnostic 1150 routines (this specific value is not counted on by the actual 1151 allocation and release functions). */ 1152 1153 len -= sizeof(struct bhead); 1154 b->bh.bsize = (bufsize) len; 1155 #ifdef FreeWipe 1156 V memset_unchecked(((char *) b) + sizeof(struct bfhead), 0x55, 1157 (MemSize) (len - sizeof(struct bfhead))); 1158 #endif 1159 bn = BH(((char *) b) + len); 1160 bn->prevfree = (bufsize) len; 1161 /* Definition of ESent assumes two's complement! */ 1162 assert((~0) == -1); 1163 bn->bsize = ESent; 1164 } 1165 1166 #ifdef BufStats 1167 1168 /* BSTATS -- Return buffer allocation free space statistics. */ 1169 1170 void bstats(curalloc, totfree, maxfree, nget, nrel, poolset) 1171 bufsize *curalloc, *totfree, *maxfree; 1172 long *nget, *nrel; 1173 struct bpoolset *poolset; 1174 { 1175 struct bfhead *b = poolset->freelist.ql.flink; 1176 1177 *nget = poolset->numget; 1178 *nrel = poolset->numrel; 1179 *curalloc = poolset->totalloc; 1180 *totfree = 0; 1181 *maxfree = -1; 1182 while (b != &poolset->freelist) { 1183 assert(b->bh.bsize > 0); 1184 *totfree += b->bh.bsize; 1185 if (b->bh.bsize > *maxfree) { 1186 *maxfree = b->bh.bsize; 1187 } 1188 b = b->ql.flink; /* Link to next buffer */ 1189 } 1190 } 1191 1192 #ifdef BECtl 1193 1194 /* BSTATSE -- Return extended statistics */ 1195 1196 void bstatse(pool_incr, npool, npget, nprel, ndget, ndrel, poolset) 1197 bufsize *pool_incr; 1198 long *npool, *npget, *nprel, *ndget, *ndrel; 1199 struct bpoolset *poolset; 1200 { 1201 *pool_incr = (poolset->pool_len < 0) ? 1202 -poolset->exp_incr : poolset->exp_incr; 1203 *npool = poolset->numpblk; 1204 *npget = poolset->numpget; 1205 *nprel = poolset->numprel; 1206 *ndget = poolset->numdget; 1207 *ndrel = poolset->numdrel; 1208 } 1209 #endif /* BECtl */ 1210 #endif /* BufStats */ 1211 1212 #ifdef DumpData 1213 1214 /* BUFDUMP -- Dump the data in a buffer. This is called with the user 1215 data pointer, and backs up to the buffer header. It will 1216 dump either a free block or an allocated one. */ 1217 1218 void bufdump(buf) 1219 void *buf; 1220 { 1221 struct bfhead *b; 1222 unsigned char *bdump; 1223 bufsize bdlen; 1224 1225 b = BFH(((char *) buf) - sizeof(struct bhead)); 1226 assert(b->bh.bsize != 0); 1227 if (b->bh.bsize < 0) { 1228 bdump = (unsigned char *) buf; 1229 bdlen = (-b->bh.bsize) - sizeof(struct bhead); 1230 } else { 1231 bdump = (unsigned char *) (((char *) b) + sizeof(struct bfhead)); 1232 bdlen = b->bh.bsize - sizeof(struct bfhead); 1233 } 1234 1235 while (bdlen > 0) { 1236 int i, dupes = 0; 1237 bufsize l = bdlen; 1238 char bhex[50], bascii[20]; 1239 1240 if (l > 16) { 1241 l = 16; 1242 } 1243 1244 for (i = 0; i < l; i++) { 1245 V snprintf(bhex + i * 3, sizeof(bhex) - i * 3, "%02X ", 1246 bdump[i]); 1247 bascii[i] = isprint(bdump[i]) ? bdump[i] : ' '; 1248 } 1249 bascii[i] = 0; 1250 V printf("%-48s %s\n", bhex, bascii); 1251 bdump += l; 1252 bdlen -= l; 1253 while ((bdlen > 16) && (memcmp((char *) (bdump - 16), 1254 (char *) bdump, 16) == 0)) { 1255 dupes++; 1256 bdump += 16; 1257 bdlen -= 16; 1258 } 1259 if (dupes > 1) { 1260 V printf( 1261 " (%d lines [%d bytes] identical to above line skipped)\n", 1262 dupes, dupes * 16); 1263 } else if (dupes == 1) { 1264 bdump -= 16; 1265 bdlen += 16; 1266 } 1267 } 1268 } 1269 #endif 1270 1271 #ifdef BufDump 1272 1273 /* BPOOLD -- Dump a buffer pool. The buffer headers are always listed. 1274 If DUMPALLOC is nonzero, the contents of allocated buffers 1275 are dumped. If DUMPFREE is nonzero, free blocks are 1276 dumped as well. If FreeWipe checking is enabled, free 1277 blocks which have been clobbered will always be dumped. */ 1278 1279 void bpoold(buf, dumpalloc, dumpfree) 1280 void *buf; 1281 int dumpalloc, dumpfree; 1282 { 1283 struct bfhead *b = BFH(buf); 1284 1285 while (b->bh.bsize != ESent) { 1286 bufsize bs = b->bh.bsize; 1287 1288 if (bs < 0) { 1289 bs = -bs; 1290 V printf("Allocated buffer: size %6ld bytes.\n", (long) bs); 1291 if (dumpalloc) { 1292 bufdump((void *) (((char *) b) + sizeof(struct bhead))); 1293 } 1294 } else { 1295 char *lerr = ""; 1296 1297 assert(bs > 0); 1298 if ((b->ql.blink->ql.flink != b) || 1299 (b->ql.flink->ql.blink != b)) { 1300 lerr = " (Bad free list links)"; 1301 } 1302 V printf("Free block: size %6ld bytes.%s\n", 1303 (long) bs, lerr); 1304 #ifdef FreeWipe 1305 lerr = ((char *) b) + sizeof(struct bfhead); 1306 if ((bs > sizeof(struct bfhead)) && ((*lerr != 0x55) || 1307 (memcmp(lerr, lerr + 1, 1308 (MemSize) (bs - (sizeof(struct bfhead) + 1))) != 0))) { 1309 V printf( 1310 "(Contents of above free block have been overstored.)\n"); 1311 bufdump((void *) (((char *) b) + sizeof(struct bhead))); 1312 } else 1313 #endif 1314 if (dumpfree) { 1315 bufdump((void *) (((char *) b) + sizeof(struct bhead))); 1316 } 1317 } 1318 b = BFH(((char *) b) + bs); 1319 } 1320 } 1321 #endif /* BufDump */ 1322 1323 #ifdef BufValid 1324 1325 /* BPOOLV -- Validate a buffer pool. If NDEBUG isn't defined, 1326 any error generates an assertion failure. */ 1327 1328 int bpoolv(buf) 1329 void *buf; 1330 { 1331 struct bfhead *b = BFH(buf); 1332 1333 while (b->bh.bsize != ESent) { 1334 bufsize bs = b->bh.bsize; 1335 1336 if (bs < 0) { 1337 bs = -bs; 1338 } else { 1339 const char *lerr = ""; 1340 1341 assert(bs > 0); 1342 if (bs <= 0) { 1343 return 0; 1344 } 1345 if ((b->ql.blink->ql.flink != b) || 1346 (b->ql.flink->ql.blink != b)) { 1347 V printf("Free block: size %6ld bytes. (Bad free list links)\n", 1348 (long) bs); 1349 assert(0); 1350 return 0; 1351 } 1352 #ifdef FreeWipe 1353 lerr = ((char *) b) + sizeof(struct bfhead); 1354 if ((bs > sizeof(struct bfhead)) && ((*lerr != 0x55) || 1355 (memcmp(lerr, lerr + 1, 1356 (MemSize) (bs - (sizeof(struct bfhead) + 1))) != 0))) { 1357 V printf( 1358 "(Contents of above free block have been overstored.)\n"); 1359 bufdump((void *) (((char *) b) + sizeof(struct bhead))); 1360 assert(0); 1361 return 0; 1362 } 1363 #endif 1364 } 1365 b = BFH(((char *) b) + bs); 1366 } 1367 return 1; 1368 } 1369 #endif /* BufValid */ 1370 1371 /***********************\ 1372 * * 1373 * Built-in test program * 1374 * * 1375 \***********************/ 1376 1377 #if !defined(__KERNEL__) && !defined(__LDELF__) && defined(CFG_TA_BGET_TEST) 1378 1379 #define TestProg 20000 1380 1381 #ifdef BECtl 1382 #define PoolSize 300000 /* Test buffer pool size */ 1383 #else 1384 #define PoolSize 50000 /* Test buffer pool size */ 1385 #endif 1386 #define ExpIncr 32768 /* Test expansion block size */ 1387 #define CompactTries 10 /* Maximum tries at compacting */ 1388 1389 #define dumpAlloc 0 /* Dump allocated buffers ? */ 1390 #define dumpFree 0 /* Dump free buffers ? */ 1391 1392 static char *bchain = NULL; /* Our private buffer chain */ 1393 static char *bp = NULL; /* Our initial buffer pool */ 1394 1395 #ifdef UsingFloat 1396 #include <math.h> 1397 #endif 1398 1399 static unsigned long int next = 1; 1400 1401 static void *(*mymalloc)(size_t size); 1402 static void (*myfree)(void *ptr); 1403 1404 static struct bpoolset mypoolset = { 1405 .freelist = { 1406 .bh = { 0, 0}, 1407 .ql = { &mypoolset.freelist, &mypoolset.freelist}, 1408 } 1409 }; 1410 1411 /* Return next random integer */ 1412 1413 static int myrand(void) 1414 { 1415 next = next * 1103515245L + 12345; 1416 return (unsigned int) (next / 65536L) % 32768L; 1417 } 1418 1419 /* Set seed for random generator */ 1420 1421 static void mysrand(unsigned int seed) 1422 { 1423 next = seed; 1424 } 1425 1426 /* STATS -- Edit statistics returned by bstats() or bstatse(). */ 1427 1428 static void stats(const char *when __maybe_unused, 1429 struct bpoolset *poolset __maybe_unused) 1430 { 1431 #ifdef BufStats 1432 bufsize cural, totfree, maxfree; 1433 long nget, nfree; 1434 #endif 1435 #ifdef BECtl 1436 bufsize pincr; 1437 long totblocks, npget, nprel, ndget, ndrel; 1438 #endif 1439 1440 #ifdef BufStats 1441 bstats(&cural, &totfree, &maxfree, &nget, &nfree, poolset); 1442 V printf( 1443 "%s: %ld gets, %ld releases. %ld in use, %ld free, largest = %ld\n", 1444 when, nget, nfree, (long) cural, (long) totfree, (long) maxfree); 1445 #endif 1446 #ifdef BECtl 1447 bstatse(&pincr, &totblocks, &npget, &nprel, &ndget, &ndrel, poolset); 1448 V printf( 1449 " Blocks: size = %ld, %ld (%ld bytes) in use, %ld gets, %ld frees\n", 1450 (long)pincr, totblocks, pincr * totblocks, npget, nprel); 1451 V printf(" %ld direct gets, %ld direct frees\n", ndget, ndrel); 1452 #endif /* BECtl */ 1453 } 1454 1455 #ifdef BECtl 1456 static int protect = 0; /* Disable compaction during bgetr() */ 1457 1458 /* BCOMPACT -- Compaction call-back function. */ 1459 1460 static int bcompact(bsize, seq) 1461 bufsize bsize; 1462 int seq; 1463 { 1464 #ifdef CompactTries 1465 char *bc = bchain; 1466 int i = myrand() & 0x3; 1467 1468 #ifdef COMPACTRACE 1469 V printf("Compaction requested. %ld bytes needed, sequence %d.\n", 1470 (long) bsize, seq); 1471 #endif 1472 1473 if (protect || (seq > CompactTries)) { 1474 #ifdef COMPACTRACE 1475 V printf("Compaction gave up.\n"); 1476 #endif 1477 return 0; 1478 } 1479 1480 /* Based on a random cast, release a random buffer in the list 1481 of allocated buffers. */ 1482 1483 while (i > 0 && bc != NULL) { 1484 bc = *((char **) bc); 1485 i--; 1486 } 1487 if (bc != NULL) { 1488 char *fb; 1489 1490 fb = *((char **) bc); 1491 if (fb != NULL) { 1492 *((char **) bc) = *((char **) fb); 1493 brel((void *) fb); 1494 return 1; 1495 } 1496 } 1497 1498 #ifdef COMPACTRACE 1499 V printf("Compaction bailed out.\n"); 1500 #endif 1501 #endif /* CompactTries */ 1502 return 0; 1503 } 1504 1505 /* BEXPAND -- Expand pool call-back function. */ 1506 1507 static void *bexpand(size) 1508 bufsize size; 1509 { 1510 void *np = NULL; 1511 bufsize cural, totfree, maxfree; 1512 long nget, nfree; 1513 1514 /* Don't expand beyond the total allocated size given by PoolSize. */ 1515 1516 bstats(&cural, &totfree, &maxfree, &nget, &nfree); 1517 1518 if (cural < PoolSize) { 1519 np = (void *) mymalloc((unsigned) size); 1520 } 1521 #ifdef EXPTRACE 1522 V printf("Expand pool by %ld -- %s.\n", (long) size, 1523 np == NULL ? "failed" : "succeeded"); 1524 #endif 1525 return np; 1526 } 1527 1528 /* BSHRINK -- Shrink buffer pool call-back function. */ 1529 1530 static void bshrink(buf) 1531 void *buf; 1532 { 1533 if (((char *) buf) == bp) { 1534 #ifdef EXPTRACE 1535 V printf("Initial pool released.\n"); 1536 #endif 1537 bp = NULL; 1538 } 1539 #ifdef EXPTRACE 1540 V printf("Shrink pool.\n"); 1541 #endif 1542 myfree((char *) buf); 1543 } 1544 1545 #endif /* BECtl */ 1546 1547 /* Restrict buffer requests to those large enough to contain our pointer and 1548 small enough for the CPU architecture. */ 1549 1550 static bufsize blimit(bufsize bs) 1551 { 1552 if (bs < sizeof(char *)) { 1553 bs = sizeof(char *); 1554 } 1555 1556 /* This is written out in this ugly fashion because the 1557 cool expression in sizeof(int) that auto-configured 1558 to any length int befuddled some compilers. */ 1559 1560 if (sizeof(int) == 2) { 1561 if (bs > 32767) { 1562 bs = 32767; 1563 } 1564 } else { 1565 if (bs > 200000) { 1566 bs = 200000; 1567 } 1568 } 1569 return bs; 1570 } 1571 1572 int bget_main_test(void *(*malloc_func)(size_t), void (*free_func)(void *)) 1573 { 1574 int i; 1575 #ifdef UsingFloat 1576 double x; 1577 #endif 1578 1579 mymalloc = malloc_func; 1580 myfree = free_func; 1581 1582 /* Seed the random number generator. If Repeatable is defined, we 1583 always use the same seed. Otherwise, we seed from the clock to 1584 shake things up from run to run. */ 1585 1586 mysrand(1234); 1587 1588 /* Compute x such that pow(x, p) ranges between 1 and 4*ExpIncr as 1589 p ranges from 0 to ExpIncr-1, with a concentration in the lower 1590 numbers. */ 1591 1592 #ifdef UsingFloat 1593 x = 4.0 * ExpIncr; 1594 x = log(x); 1595 x = exp(log(4.0 * ExpIncr) / (ExpIncr - 1.0)); 1596 #endif 1597 1598 #ifdef BECtl 1599 bectl(bcompact, bexpand, bshrink, (bufsize) ExpIncr, &mypoolset); 1600 bp = mymalloc(ExpIncr); 1601 assert(bp != NULL); 1602 bpool((void *) bp, (bufsize) ExpIncr); 1603 #else 1604 bp = mymalloc(PoolSize); 1605 assert(bp != NULL); 1606 bpool((void *) bp, (bufsize) PoolSize, &mypoolset); 1607 #endif 1608 1609 stats("Create pool", &mypoolset); 1610 #ifdef BufValid 1611 V bpoolv((void *) bp); 1612 #endif 1613 #ifdef BufDump 1614 bpoold((void *) bp, dumpAlloc, dumpFree); 1615 #endif 1616 1617 for (i = 0; i < TestProg; i++) { 1618 char *cb; 1619 #ifdef UsingFloat 1620 bufsize bs = pow(x, (double) (myrand() & (ExpIncr - 1))); 1621 #else 1622 bufsize bs = (myrand() & (ExpIncr * 4 - 1)) / (1 << (myrand() & 0x7)); 1623 #endif 1624 bufsize align = 0; 1625 bufsize hdr_size = 0; 1626 1627 switch (rand() & 0x3) { 1628 case 1: 1629 align = 32; 1630 break; 1631 case 2: 1632 align = 64; 1633 break; 1634 case 3: 1635 align = 128; 1636 break; 1637 default: 1638 break; 1639 } 1640 1641 hdr_size = (rand() & 0x3) * BGET_HDR_QUANTUM; 1642 1643 assert(bs <= (((bufsize) 4) * ExpIncr)); 1644 bs = blimit(bs); 1645 if (myrand() & 0x400) { 1646 cb = (char *) bgetz(align, hdr_size, bs, &mypoolset); 1647 } else { 1648 cb = (char *) bget(align, hdr_size, bs, &mypoolset); 1649 } 1650 if (cb == NULL) { 1651 #ifdef EasyOut 1652 break; 1653 #else 1654 char *bc = bchain; 1655 1656 if (bc != NULL) { 1657 char *fb; 1658 1659 fb = *((char **) bc); 1660 if (fb != NULL) { 1661 *((char **) bc) = *((char **) fb); 1662 brel((void *) fb, &mypoolset, true/*wipe*/); 1663 } 1664 } 1665 continue; 1666 #endif 1667 } 1668 assert(!align || !(((unsigned long)cb + hdr_size) & (align - 1))); 1669 *((char **) cb) = (char *) bchain; 1670 bchain = cb; 1671 1672 /* Based on a random cast, release a random buffer in the list 1673 of allocated buffers. */ 1674 1675 if ((myrand() & 0x10) == 0) { 1676 char *bc = bchain; 1677 int j = myrand() & 0x3; 1678 1679 while (j > 0 && bc != NULL) { 1680 bc = *((char **) bc); 1681 j--; 1682 } 1683 if (bc != NULL) { 1684 char *fb; 1685 1686 fb = *((char **) bc); 1687 if (fb != NULL) { 1688 *((char **) bc) = *((char **) fb); 1689 brel((void *) fb, &mypoolset, true/*wipe*/); 1690 } 1691 } 1692 } 1693 1694 /* Based on a random cast, reallocate a random buffer in the list 1695 to a random size */ 1696 1697 if ((myrand() & 0x20) == 0) { 1698 char *bc = bchain; 1699 int j = myrand() & 0x3; 1700 1701 while (j > 0 && bc != NULL) { 1702 bc = *((char **) bc); 1703 j--; 1704 } 1705 if (bc != NULL) { 1706 char *fb; 1707 1708 fb = *((char **) bc); 1709 if (fb != NULL) { 1710 char *newb; 1711 1712 #ifdef UsingFloat 1713 bs = pow(x, (double) (myrand() & (ExpIncr - 1))); 1714 #else 1715 bs = (rand() & (ExpIncr * 4 - 1)) / (1 << (rand() & 0x7)); 1716 #endif 1717 bs = blimit(bs); 1718 #ifdef BECtl 1719 protect = 1; /* Protect against compaction */ 1720 #endif 1721 newb = (char *) bgetr((void *) fb, align, hdr_size, bs, &mypoolset); 1722 #ifdef BECtl 1723 protect = 0; 1724 #endif 1725 if (newb != NULL) { 1726 assert(!align || !(((unsigned long)newb + hdr_size) & 1727 (align - 1))); 1728 *((char **) bc) = newb; 1729 } 1730 } 1731 } 1732 } 1733 } 1734 stats("\nAfter allocation", &mypoolset); 1735 if (bp != NULL) { 1736 #ifdef BufValid 1737 V bpoolv((void *) bp); 1738 #endif 1739 #ifdef BufDump 1740 bpoold((void *) bp, dumpAlloc, dumpFree); 1741 #endif 1742 } 1743 1744 while (bchain != NULL) { 1745 char *buf = bchain; 1746 1747 bchain = *((char **) buf); 1748 brel((void *) buf, &mypoolset, true/*wipe*/); 1749 } 1750 stats("\nAfter release", &mypoolset); 1751 #ifndef BECtl 1752 if (bp != NULL) { 1753 #ifdef BufValid 1754 V bpoolv((void *) bp); 1755 #endif 1756 #ifdef BufDump 1757 bpoold((void *) bp, dumpAlloc, dumpFree); 1758 #endif 1759 } 1760 #endif 1761 1762 return 0; 1763 } 1764 #endif 1765