src/src/store.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2018 */
   6 /* Copyright (c) The Exim maintainers 2019 */
   7 /* See the file NOTICE for conditions of use and distribution. */
   8
   9 /* Exim gets and frees all its store through these functions. In the original
  10 implementation there was a lot of mallocing and freeing of small bits of store.
  11 The philosophy has now changed to a scheme which includes the concept of
  12 "stacking pools" of store. For the short-lived processes, there isn't any real
  13 need to do any garbage collection, but the stack concept allows quick resetting
  14 in places where this seems sensible.
  15
  16 Obviously the long-running processes (the daemon, the queue runner, and eximon)
  17 must take care not to eat store.
  18
  19 The following different types of store are recognized:
  20
  21 . Long-lived, large blocks: This is implemented by retaining the original
  22   malloc/free functions, and it used for permanent working buffers and for
  23   getting blocks to cut up for the other types.
  24
  25 . Long-lived, small blocks: This is used for blocks that have to survive until
  26   the process exits. It is implemented as a stacking pool (POOL_PERM). This is
  27   functionally the same as store_malloc(), except that the store can't be
  28   freed, but I expect it to be more efficient for handling small blocks.
  29
  30 . Short-lived, short blocks: Most of the dynamic store falls into this
  31   category. It is implemented as a stacking pool (POOL_MAIN) which is reset
  32   after accepting a message when multiple messages are received by a single
  33   process. Resetting happens at some other times as well, usually fairly
  34   locally after some specific processing that needs working store.
  35
  36 . There is a separate pool (POOL_SEARCH) that is used only for lookup storage.
  37   This means it can be freed when search_tidyup() is called to close down all
  38   the lookup caching.
  39
  40 . Orthogonal to the three pool types, there are two classes of memory: untainted
  41   and tainted.  The latter is used for values derived from untrusted input, and
  42   the string-expansion mechanism refuses to operate on such values (obviously,
  43   it can expand an untainted value to return a tainted result).  The classes
  44   are implemented by duplicating the three pool types. Pool resets are requested
  45   against the nontainted sibling and apply to both siblings.
  46 */
  47
  48
  49 #include "exim.h"
  50 /* keep config.h before memcheck.h, for NVALGRIND */
  51 #include "config.h"
  52
  53 #include <sys/mman.h>
  54 #include "memcheck.h"
  55
  56
  57 /* We need to know how to align blocks of data for general use. I'm not sure
  58 how to get an alignment factor in general. In the current world, a value of 8
  59 is probably right, and this is sizeof(double) on some systems and sizeof(void
  60 *) on others, so take the larger of those. Since everything in this expression
  61 is a constant, the compiler should optimize it to a simple constant wherever it
  62 appears (I checked that gcc does do this). */
  63
  64 #define alignment \
  65   (sizeof(void *) > sizeof(double) ? sizeof(void *) : sizeof(double))
  66
  67 /* store_reset() will not free the following block if the last used block has
  68 less than this much left in it. */
  69
  70 #define STOREPOOL_MIN_SIZE 256
  71
  72 /* Structure describing the beginning of each big block. */
  73
  74 typedef struct storeblock {
  75   struct storeblock *next;
  76   size_t length;
  77 } storeblock;
  78
  79 /* Just in case we find ourselves on a system where the structure above has a
  80 length that is not a multiple of the alignment, set up a macro for the padded
  81 length. */
  82
  83 #define ALIGNED_SIZEOF_STOREBLOCK \
  84   (((sizeof(storeblock) + alignment - 1) / alignment) * alignment)
  85
  86 /* Size of block to get from malloc to carve up into smaller ones. This
  87 must be a multiple of the alignment. We assume that 8192 is going to be
  88 suitably aligned. */
  89
  90 #define STORE_BLOCK_SIZE (8192 - ALIGNED_SIZEOF_STOREBLOCK)
  91
  92 /* Variables holding data for the local pools of store. The current pool number
  93 is held in store_pool, which is global so that it can be changed from outside.
  94 Setting the initial length values to -1 forces a malloc for the first call,
  95 even if the length is zero (which is used for getting a point to reset to). */
  96
  97 int store_pool = POOL_MAIN;
  98
  99 #define NPOOLS 6
 100 static storeblock *chainbase[NPOOLS];
 101 static storeblock *current_block[NPOOLS];
 102 static void *next_yield[NPOOLS];
 103 static int yield_length[NPOOLS] = { -1, -1, -1,  -1, -1, -1 };
 104
 105 /* The limits of the tainted pools.  Tracking these on new allocations enables
 106 a fast is_tainted implementation. We assume the kernel only allocates mmaps using
 107 one side or the other of data+heap, not both. */
 108
 109 void * tainted_base = (void *)-1;
 110 void * tainted_top = (void *)0;
 111
 112 /* pool_malloc holds the amount of memory used by the store pools; this goes up
 113 and down as store is reset or released. nonpool_malloc is the total got by
 114 malloc from other calls; this doesn't go down because it is just freed by
 115 pointer. */
 116
 117 static int pool_malloc;
 118 static int nonpool_malloc;
 119
 120 /* This variable is set by store_get() to its yield, and by store_reset() to
 121 NULL. This enables string_cat() to optimize its store handling for very long
 122 strings. That's why the variable is global. */
 123
 124 void *store_last_get[NPOOLS];
 125
 126 /* These are purely for stats-gathering */
 127
 128 static int nbytes[NPOOLS];      /* current bytes allocated */
 129 static int maxbytes[NPOOLS];    /* max number reached */
 130 static int nblocks[NPOOLS];     /* current number of blocks allocated */
 131 static int maxblocks[NPOOLS];
 132 static int n_nonpool_blocks;    /* current number of direct store_malloc() blocks */
 133 static int max_nonpool_blocks;
 134 static int max_pool_malloc;     /* max value for pool_malloc */
 135 static int max_nonpool_malloc;  /* max value for nonpool_malloc */
 136
 137
 138 #ifndef COMPILE_UTILITY
 139 static const uschar * pooluse[NPOOLS] = {
 140 [POOL_MAIN] =           US"main",
 141 [POOL_PERM] =           US"perm",
 142 [POOL_SEARCH] =         US"search",
 143 [POOL_TAINT_MAIN] =     US"main",
 144 [POOL_TAINT_PERM] =     US"perm",
 145 [POOL_TAINT_SEARCH] =   US"search",
 146 };
 147 static const uschar * poolclass[NPOOLS] = {
 148 [POOL_MAIN] =           US"untainted",
 149 [POOL_PERM] =           US"untainted",
 150 [POOL_SEARCH] =         US"untainted",
 151 [POOL_TAINT_MAIN] =     US"tainted",
 152 [POOL_TAINT_PERM] =     US"tainted",
 153 [POOL_TAINT_SEARCH] =   US"tainted",
 154 };
 155 #endif
 156
 157
 158 static void * store_mmap(int, const char *, int);
 159 static void * internal_store_malloc(int, const char *, int);
 160 static void   internal_store_free(void *, const char *, int linenumber);
 161
 162 /******************************************************************************/
 163
 164 /* Slower version check, for use when platform intermixes malloc and mmap area
 165 addresses. */
 166
 167 BOOL
 168 is_tainted_fn(const void * p)
 169 {
 170 storeblock * b;
 171 int pool;
 172
 173 for (pool = 0; pool < nelem(chainbase); pool++)
 174   if ((b = current_block[pool]))
 175     {
 176     char * bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 177     if (CS p >= bc && CS p <= bc + b->length) goto hit;
 178     }
 179
 180 for (pool = 0; pool < nelem(chainbase); pool++)
 181   for (b = chainbase[pool]; b; b = b->next)
 182     {
 183     char * bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 184     if (CS p >= bc && CS p <= bc + b->length) goto hit;
 185     }
 186 return FALSE;
 187
 188 hit:
 189 return pool >= POOL_TAINT_BASE;
 190 }
 191
 192
 193 void
 194 die_tainted(const uschar * msg, const uschar * func, int line)
 195 {
 196 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Taint mismatch, %s: %s %d\n",
 197         msg, func, line);
 198 }
 199
 200
 201 /*************************************************
 202 *       Get a block from the current pool        *
 203 *************************************************/
 204
 205 /* Running out of store is a total disaster. This function is called via the
 206 macro store_get(). It passes back a block of store within the current big
 207 block, getting a new one if necessary. The address is saved in
 208 store_last_was_get.
 209
 210 Arguments:
 211   size        amount wanted
 212   func        function from which called
 213   linenumber  line number in source file
 214
 215 Returns:      pointer to store (panic on malloc failure)
 216 */
 217
 218 void *
 219 store_get_3(int size, BOOL tainted, const char *func, int linenumber)
 220 {
 221 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
 222
 223 /* Round up the size to a multiple of the alignment. Although this looks a
 224 messy statement, because "alignment" is a constant expression, the compiler can
 225 do a reasonable job of optimizing, especially if the value of "alignment" is a
 226 power of two. I checked this with -O2, and gcc did very well, compiling it to 4
 227 instructions on a Sparc (alignment = 8). */
 228
 229 if (size % alignment != 0) size += alignment - (size % alignment);
 230
 231 /* If there isn't room in the current block, get a new one. The minimum
 232 size is STORE_BLOCK_SIZE, and we would expect this to be the norm, since
 233 these functions are mostly called for small amounts of store. */
 234
 235 if (size > yield_length[pool])
 236   {
 237   int length = size <= STORE_BLOCK_SIZE ? STORE_BLOCK_SIZE : size;
 238   int mlength = length + ALIGNED_SIZEOF_STOREBLOCK;
 239   storeblock * newblock;
 240
 241   /* Sometimes store_reset() may leave a block for us; check if we can use it */
 242
 243   if (  (newblock = current_block[pool])
 244      && (newblock = newblock->next)
 245      && newblock->length < length
 246      )
 247     {
 248     /* Give up on this block, because it's too small */
 249     nblocks[pool]--;
 250     if (pool < POOL_TAINT_BASE)
 251       internal_store_free(newblock, func, linenumber);
 252     else
 253       {
 254 #ifndef COMPILE_UTILITY
 255       DEBUG(D_memory)
 256         debug_printf("---Unmap %6p %-20s %4d\n", newblock, func, linenumber);
 257 #endif
 258       munmap(newblock, newblock->length + ALIGNED_SIZEOF_STOREBLOCK);
 259       }
 260     newblock = NULL;
 261     }
 262
 263   /* If there was no free block, get a new one */
 264
 265   if (!newblock)
 266     {
 267     if ((nbytes[pool] += mlength) > maxbytes[pool])
 268       maxbytes[pool] = nbytes[pool];
 269     if ((pool_malloc += mlength) > max_pool_malloc)     /* Used in pools */
 270       max_pool_malloc = pool_malloc;
 271     nonpool_malloc -= mlength;                  /* Exclude from overall total */
 272     if (++nblocks[pool] > maxblocks[pool])
 273       maxblocks[pool] = nblocks[pool];
 274
 275     newblock = tainted
 276       ? store_mmap(mlength, func, linenumber)
 277       : internal_store_malloc(mlength, func, linenumber);
 278     newblock->next = NULL;
 279     newblock->length = length;
 280
 281     if (!chainbase[pool])
 282       chainbase[pool] = newblock;
 283     else
 284       current_block[pool]->next = newblock;
 285     }
 286
 287   current_block[pool] = newblock;
 288   yield_length[pool] = newblock->length;
 289   next_yield[pool] =
 290     (void *)(CS current_block[pool] + ALIGNED_SIZEOF_STOREBLOCK);
 291   (void) VALGRIND_MAKE_MEM_NOACCESS(next_yield[pool], yield_length[pool]);
 292   }
 293
 294 /* There's (now) enough room in the current block; the yield is the next
 295 pointer. */
 296
 297 store_last_get[pool] = next_yield[pool];
 298
 299 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 300 giving warnings. */
 301
 302 #ifdef COMPILE_UTILITY
 303 func = func;
 304 linenumber = linenumber;
 305 #else
 306 DEBUG(D_memory)
 307   debug_printf("---%d Get %6p %5d %-14s %4d\n", pool,
 308     store_last_get[pool], size, func, linenumber);
 309 #endif  /* COMPILE_UTILITY */
 310
 311 (void) VALGRIND_MAKE_MEM_UNDEFINED(store_last_get[pool], size);
 312 /* Update next pointer and number of bytes left in the current block. */
 313
 314 next_yield[pool] = (void *)(CS next_yield[pool] + size);
 315 yield_length[pool] -= size;
 316 return store_last_get[pool];
 317 }
 318
 319
 320
 321 /*************************************************
 322 *       Get a block from the PERM pool           *
 323 *************************************************/
 324
 325 /* This is just a convenience function, useful when just a single block is to
 326 be obtained.
 327
 328 Arguments:
 329   size        amount wanted
 330   func        function from which called
 331   linenumber  line number in source file
 332
 333 Returns:      pointer to store (panic on malloc failure)
 334 */
 335
 336 void *
 337 store_get_perm_3(int size, BOOL tainted, const char *func, int linenumber)
 338 {
 339 void *yield;
 340 int old_pool = store_pool;
 341 store_pool = POOL_PERM;
 342 yield = store_get_3(size, tainted, func, linenumber);
 343 store_pool = old_pool;
 344 return yield;
 345 }
 346
 347
 348
 349 /*************************************************
 350 *      Extend a block if it is at the top        *
 351 *************************************************/
 352
 353 /* While reading strings of unknown length, it is often the case that the
 354 string is being read into the block at the top of the stack. If it needs to be
 355 extended, it is more efficient just to extend within the top block rather than
 356 allocate a new block and then have to copy the data. This function is provided
 357 for the use of string_cat(), but of course can be used elsewhere too.
 358 The block itself is not expanded; only the top allocation from it.
 359
 360 Arguments:
 361   ptr        pointer to store block
 362   oldsize    current size of the block, as requested by user
 363   newsize    new size required
 364   func       function from which called
 365   linenumber line number in source file
 366
 367 Returns:     TRUE if the block is at the top of the stack and has been
 368              extended; FALSE if it isn't at the top of the stack, or cannot
 369              be extended
 370 */
 371
 372 BOOL
 373 store_extend_3(void *ptr, BOOL tainted, int oldsize, int newsize,
 374    const char *func, int linenumber)
 375 {
 376 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
 377 int inc = newsize - oldsize;
 378 int rounded_oldsize = oldsize;
 379
 380 /* Check that the block being extended was already of the required taint status;
 381 refuse to extend if not. */
 382
 383 if (is_tainted(ptr) != tainted)
 384   return FALSE;
 385
 386 if (rounded_oldsize % alignment != 0)
 387   rounded_oldsize += alignment - (rounded_oldsize % alignment);
 388
 389 if (CS ptr + rounded_oldsize != CS (next_yield[pool]) ||
 390     inc > yield_length[pool] + rounded_oldsize - oldsize)
 391   return FALSE;
 392
 393 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 394 giving warnings. */
 395
 396 #ifdef COMPILE_UTILITY
 397 func = func;
 398 linenumber = linenumber;
 399 #else
 400 DEBUG(D_memory)
 401   debug_printf("---%d Ext %6p %5d %-14s %4d\n", pool, ptr, newsize,
 402     func, linenumber);
 403 #endif  /* COMPILE_UTILITY */
 404
 405 if (newsize % alignment != 0) newsize += alignment - (newsize % alignment);
 406 next_yield[pool] = CS ptr + newsize;
 407 yield_length[pool] -= newsize - rounded_oldsize;
 408 (void) VALGRIND_MAKE_MEM_UNDEFINED(ptr + oldsize, inc);
 409 return TRUE;
 410 }
 411
 412
 413
 414
 415 /*************************************************
 416 *    Back up to a previous point on the stack    *
 417 *************************************************/
 418
 419 /* This function resets the next pointer, freeing any subsequent whole blocks
 420 that are now unused. Call with a cookie obtained from store_mark() only; do
 421 not call with a pointer returned by store_get().  Both the untainted and tainted
 422 pools corresposding to store_pool are reset.
 423
 424 Arguments:
 425   r           place to back up to
 426   func        function from which called
 427   linenumber  line number in source file
 428
 429 Returns:      nothing
 430 */
 431
 432 static void
 433 internal_store_reset(void * ptr, int pool, const char *func, int linenumber)
 434 {
 435 storeblock * bb;
 436 storeblock * b = current_block[pool];
 437 char * bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 438 int newlength, count;
 439 #ifndef COMPILE_UTILITY
 440 int oldmalloc = pool_malloc;
 441 #endif
 442
 443 /* Last store operation was not a get */
 444
 445 store_last_get[pool] = NULL;
 446
 447 /* See if the place is in the current block - as it often will be. Otherwise,
 448 search for the block in which it lies. */
 449
 450 if (CS ptr < bc || CS ptr > bc + b->length)
 451   {
 452   for (b = chainbase[pool]; b; b = b->next)
 453     {
 454     bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 455     if (CS ptr >= bc && CS ptr <= bc + b->length) break;
 456     }
 457   if (!b)
 458     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "internal error: store_reset(%p) "
 459       "failed: pool=%d %-14s %4d", ptr, pool, func, linenumber);
 460   }
 461
 462 /* Back up, rounding to the alignment if necessary. When testing, flatten
 463 the released memory. */
 464
 465 newlength = bc + b->length - CS ptr;
 466 #ifndef COMPILE_UTILITY
 467 if (debug_store)
 468   {
 469   assert_no_variables(ptr, newlength, func, linenumber);
 470   if (f.running_in_test_harness)
 471     {
 472     (void) VALGRIND_MAKE_MEM_DEFINED(ptr, newlength);
 473     memset(ptr, 0xF0, newlength);
 474     }
 475   }
 476 #endif
 477 (void) VALGRIND_MAKE_MEM_NOACCESS(ptr, newlength);
 478 next_yield[pool] = CS ptr + (newlength % alignment);
 479 count = yield_length[pool];
 480 count = (yield_length[pool] = newlength - (newlength % alignment)) - count;
 481 current_block[pool] = b;
 482
 483 /* Free any subsequent block. Do NOT free the first
 484 successor, if our current block has less than 256 bytes left. This should
 485 prevent us from flapping memory. However, keep this block only when it has
 486 the default size. */
 487
 488 if (  yield_length[pool] < STOREPOOL_MIN_SIZE
 489    && b->next
 490    && b->next->length == STORE_BLOCK_SIZE)
 491   {
 492   b = b->next;
 493 #ifndef COMPILE_UTILITY
 494   if (debug_store)
 495     assert_no_variables(b, b->length + ALIGNED_SIZEOF_STOREBLOCK,
 496                         func, linenumber);
 497 #endif
 498   (void) VALGRIND_MAKE_MEM_NOACCESS(CS b + ALIGNED_SIZEOF_STOREBLOCK,
 499                 b->length - ALIGNED_SIZEOF_STOREBLOCK);
 500   }
 501
 502 bb = b->next;
 503 b->next = NULL;
 504
 505 while ((b = bb))
 506   {
 507   int siz = b->length + ALIGNED_SIZEOF_STOREBLOCK;
 508 #ifndef COMPILE_UTILITY
 509   if (debug_store)
 510     assert_no_variables(b, b->length + ALIGNED_SIZEOF_STOREBLOCK,
 511                         func, linenumber);
 512 #endif
 513   bb = bb->next;
 514   nbytes[pool] -= siz;
 515   pool_malloc -= siz;
 516   nblocks[pool]--;
 517   if (pool < POOL_TAINT_BASE)
 518     internal_store_free(b, func, linenumber);
 519   else
 520     {
 521 #ifndef COMPILE_UTILITY
 522     DEBUG(D_memory)
 523       debug_printf("---Unmap %6p %-20s %4d\n", b, func, linenumber);
 524 #endif
 525     munmap(b, b->length + ALIGNED_SIZEOF_STOREBLOCK);
 526     }
 527   }
 528
 529 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 530 giving warnings. */
 531
 532 #ifdef COMPILE_UTILITY
 533 func = func;
 534 linenumber = linenumber;
 535 #else
 536 DEBUG(D_memory)
 537   debug_printf("---%d Rst %6p %5d %-14s %4d %d\n", pool, ptr,
 538     count + oldmalloc - pool_malloc,
 539     func, linenumber, pool_malloc);
 540 #endif  /* COMPILE_UTILITY */
 541 }
 542
 543
 544 rmark
 545 store_reset_3(rmark r, int pool, const char *func, int linenumber)
 546 {
 547 void ** ptr = r;
 548
 549 if (pool >= POOL_TAINT_BASE)
 550   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
 551     "store_reset called for pool %d: %s %d\n", pool, func, linenumber);
 552 if (!r)
 553   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
 554     "store_reset called with bad mark: %s %d\n", func, linenumber);
 555
 556 internal_store_reset(*ptr, pool + POOL_TAINT_BASE, func, linenumber);
 557 internal_store_reset(ptr,  pool,                   func, linenumber);
 558 return NULL;
 559 }
 560
 561
 562
 563 /* Free tail-end unused allocation.  This lets us allocate a big chunk
 564 early, for cases when we only discover later how much was really needed.
 565
 566 Can be called with a value from store_get(), or an offset after such.  Only
 567 the tainted or untainted pool that serviced the store_get() will be affected.
 568
 569 This is mostly a cut-down version of internal_store_reset().
 570 XXX needs rationalising
 571 */
 572
 573 void
 574 store_release_above_3(void *ptr, const char *func, int linenumber)
 575 {
 576 /* Search all pools' "current" blocks.  If it isn't one of those,
 577 ignore it (it usually will be). */
 578
 579 for (int pool = 0; pool < nelem(current_block); pool++)
 580   {
 581   storeblock * b = current_block[pool];
 582   char * bc;
 583   int count, newlength;
 584
 585   if (!b)
 586     continue;
 587
 588   bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 589   if (CS ptr < bc || CS ptr > bc + b->length)
 590     continue;
 591
 592   /* Last store operation was not a get */
 593
 594   store_last_get[pool] = NULL;
 595
 596   /* Back up, rounding to the alignment if necessary. When testing, flatten
 597   the released memory. */
 598
 599   newlength = bc + b->length - CS ptr;
 600 #ifndef COMPILE_UTILITY
 601   if (debug_store)
 602     {
 603     assert_no_variables(ptr, newlength, func, linenumber);
 604     if (f.running_in_test_harness)
 605       {
 606       (void) VALGRIND_MAKE_MEM_DEFINED(ptr, newlength);
 607       memset(ptr, 0xF0, newlength);
 608       }
 609     }
 610 #endif
 611   (void) VALGRIND_MAKE_MEM_NOACCESS(ptr, newlength);
 612   next_yield[pool] = CS ptr + (newlength % alignment);
 613   count = yield_length[pool];
 614   count = (yield_length[pool] = newlength - (newlength % alignment)) - count;
 615
 616   /* Cut out the debugging stuff for utilities, but stop picky compilers from
 617   giving warnings. */
 618
 619 #ifdef COMPILE_UTILITY
 620   func = func;
 621   linenumber = linenumber;
 622 #else
 623   DEBUG(D_memory)
 624     debug_printf("---%d Rel %6p %5d %-14s %4d %d\n", pool, ptr, count,
 625       func, linenumber, pool_malloc);
 626 #endif
 627   return;
 628   }
 629 #ifndef COMPILE_UTILITY
 630 DEBUG(D_memory)
 631   debug_printf("non-last memory release try: %s %d\n", func, linenumber);
 632 #endif
 633 }
 634
 635
 636
 637 rmark
 638 store_mark_3(const char *func, int linenumber)
 639 {
 640 void ** p;
 641
 642 if (store_pool >= POOL_TAINT_BASE)
 643   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
 644     "store_mark called for pool %d: %s %d\n", store_pool, func, linenumber);
 645
 646 /* Stash a mark for the tainted-twin release, in the untainted twin. Return
 647 a cookie (actually the address in the untainted pool) to the caller.
 648 Reset uses the cookie to recover the t-mark, winds back the tainted pool with it
 649 and winds back the untainted pool with the cookie. */
 650
 651 p = store_get_3(sizeof(void *), FALSE, func, linenumber);
 652 *p = store_get_3(0, TRUE, func, linenumber);
 653 return p;
 654 }
 655
 656
 657
 658
 659 /************************************************
 660 *             Release store                     *
 661 ************************************************/
 662
 663 /* This function checks that the pointer it is given is the first thing in a
 664 block, and if so, releases that block.
 665
 666 Arguments:
 667   block       block of store to consider
 668   func        function from which called
 669   linenumber  line number in source file
 670
 671 Returns:      nothing
 672 */
 673
 674 static void
 675 store_release_3(void * block, int pool, const char * func, int linenumber)
 676 {
 677 /* It will never be the first block, so no need to check that. */
 678
 679 for (storeblock * b = chainbase[pool]; b; b = b->next)
 680   {
 681   storeblock * bb = b->next;
 682   if (bb && CS block == CS bb + ALIGNED_SIZEOF_STOREBLOCK)
 683     {
 684     int siz = bb->length + ALIGNED_SIZEOF_STOREBLOCK;
 685     b->next = bb->next;
 686     nbytes[pool] -= siz;
 687     pool_malloc -= siz;
 688     nblocks[pool]--;
 689
 690     /* Cut out the debugging stuff for utilities, but stop picky compilers
 691     from giving warnings. */
 692
 693 #ifdef COMPILE_UTILITY
 694     func = func;
 695     linenumber = linenumber;
 696 #else
 697     DEBUG(D_memory)
 698       debug_printf("-Release %6p %-20s %4d %d\n", (void *)bb, func,
 699         linenumber, pool_malloc);
 700
 701     if (f.running_in_test_harness)
 702       memset(bb, 0xF0, bb->length+ALIGNED_SIZEOF_STOREBLOCK);
 703 #endif  /* COMPILE_UTILITY */
 704
 705     free(bb);
 706     return;
 707     }
 708   }
 709 }
 710
 711
 712 /************************************************
 713 *             Move store                        *
 714 ************************************************/
 715
 716 /* Allocate a new block big enough to expend to the given size and
 717 copy the current data into it.  Free the old one if possible.
 718
 719 This function is specifically provided for use when reading very
 720 long strings, e.g. header lines. When the string gets longer than a
 721 complete block, it gets copied to a new block. It is helpful to free
 722 the old block iff the previous copy of the string is at its start,
 723 and therefore the only thing in it. Otherwise, for very long strings,
 724 dead store can pile up somewhat disastrously. This function checks that
 725 the pointer it is given is the first thing in a block, and that nothing
 726 has been allocated since. If so, releases that block.
 727
 728 Arguments:
 729   block
 730   newsize
 731   len
 732
 733 Returns:        new location of data
 734 */
 735
 736 void *
 737 store_newblock_3(void * block, BOOL tainted, int newsize, int len,
 738   const char * func, int linenumber)
 739 {
 740 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
 741 BOOL release_ok = !tainted && store_last_get[pool] == block;
 742 uschar * newtext;
 743
 744 #ifndef MACRO_PREDEF
 745 if (is_tainted(block) != tainted)
 746   die_tainted(US"store_newblock", CUS func, linenumber);
 747 #endif
 748
 749 newtext = store_get(newsize, tainted);
 750 memcpy(newtext, block, len);
 751 if (release_ok) store_release_3(block, pool, func, linenumber);
 752 return (void *)newtext;
 753 }
 754
 755
 756
 757
 758 /******************************************************************************/
 759 static void *
 760 store_alloc_tail(void * yield, int size, const char * func, int line,
 761   const uschar * type)
 762 {
 763 if ((nonpool_malloc += size) > max_nonpool_malloc)
 764   max_nonpool_malloc = nonpool_malloc;
 765
 766 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 767 giving warnings. */
 768
 769 #ifdef COMPILE_UTILITY
 770 func = func; line = line; type = type;
 771 #else
 772
 773 /* If running in test harness, spend time making sure all the new store
 774 is not filled with zeros so as to catch problems. */
 775
 776 if (f.running_in_test_harness)
 777   memset(yield, 0xF0, (size_t)size);
 778 DEBUG(D_memory) debug_printf("--%6s %6p %5d bytes\t%-14s %4d\tpool %5d  nonpool %5d\n",
 779   type, yield, size, func, line, pool_malloc, nonpool_malloc);
 780 #endif  /* COMPILE_UTILITY */
 781
 782 return yield;
 783 }
 784
 785 /*************************************************
 786 *                Mmap store                      *
 787 *************************************************/
 788
 789 static void *
 790 store_mmap(int size, const char * func, int line)
 791 {
 792 void * yield, * top;
 793
 794 if (size < 16) size = 16;
 795
 796 if (!(yield = mmap(NULL, (size_t)size,
 797                   PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)))
 798   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to mmap %d bytes of memory: "
 799     "called from line %d of %s", size, line, func);
 800
 801 if (yield < tainted_base) tainted_base = yield;
 802 if ((top = yield + size) > tainted_top) tainted_top = top;
 803
 804 return store_alloc_tail(yield, size, func, line, US"Mmap");
 805 }
 806
 807 /*************************************************
 808 *                Malloc store                    *
 809 *************************************************/
 810
 811 /* Running out of store is a total disaster for exim. Some malloc functions
 812 do not run happily on very small sizes, nor do they document this fact. This
 813 function is called via the macro store_malloc().
 814
 815 Arguments:
 816   size        amount of store wanted
 817   func        function from which called
 818   linenumber  line number in source file
 819
 820 Returns:      pointer to gotten store (panic on failure)
 821 */
 822
 823 static void *
 824 internal_store_malloc(int size, const char *func, int linenumber)
 825 {
 826 void * yield;
 827
 828 if (size < 16) size = 16;
 829
 830 if (!(yield = malloc((size_t)size)))
 831   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to malloc %d bytes of memory: "
 832     "called from line %d in %s", size, linenumber, func);
 833
 834 return store_alloc_tail(yield, size, func, linenumber, US"Malloc");
 835 }
 836
 837 void *
 838 store_malloc_3(int size, const char *func, int linenumber)
 839 {
 840 if (n_nonpool_blocks++ > max_nonpool_blocks)
 841   max_nonpool_blocks = n_nonpool_blocks;
 842 return internal_store_malloc(size, func, linenumber);
 843 }
 844
 845
 846 /************************************************
 847 *             Free store                        *
 848 ************************************************/
 849
 850 /* This function is called by the macro store_free().
 851
 852 Arguments:
 853   block       block of store to free
 854   func        function from which called
 855   linenumber  line number in source file
 856
 857 Returns:      nothing
 858 */
 859
 860 static void
 861 internal_store_free(void *block, const char *func, int linenumber)
 862 {
 863 #ifdef COMPILE_UTILITY
 864 func = func;
 865 linenumber = linenumber;
 866 #else
 867 DEBUG(D_memory)
 868   debug_printf("----Free %6p %-20s %4d\n", block, func, linenumber);
 869 #endif  /* COMPILE_UTILITY */
 870 free(block);
 871 }
 872
 873 void
 874 store_free_3(void *block, const char *func, int linenumber)
 875 {
 876 n_nonpool_blocks--;
 877 internal_store_free(block, func, linenumber);
 878 }
 879
 880 /******************************************************************************/
 881 /* Stats output on process exit */
 882 void
 883 store_exit(void)
 884 {
 885 #ifndef COMPILE_UTILITY
 886 DEBUG(D_memory)
 887  {
 888  debug_printf("----Exit nonpool max: %3d kB in %d blocks\n",
 889   (max_nonpool_malloc+1023)/1024, max_nonpool_blocks);
 890  debug_printf("----Exit npools  max: %3d kB\n", max_pool_malloc/1024);
 891  for (int i = 0; i < NPOOLS; i++)
 892   debug_printf("----Exit  pool %d max: %3d kB in %d blocks\t%s %s\n",
 893     i, maxbytes[i]/1024, maxblocks[i], poolclass[i], pooluse[i]);
 894  }
 895 #endif
 896 }
 897
 898 /* End of store.c */