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 - 2020 */
   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   Only memory blocks requested for tainted use are regarded as tainted; anything
  48   else (including stack auto variables) is untainted.  Care is needed when coding
  49   to not copy untrusted data into untainted memory, as downstream taint-checks
  50   would be avoided.
  51
  52   Intermediate layers (eg. the string functions) can test for taint, and use this
  53   for ensurinng that results have proper state.  For example the
  54   string_vformat_trc() routing supporting the string_sprintf() interface will
  55   recopy a string being built into a tainted allocation if it meets a %s for a
  56   tainted argument.  Any intermediate-layer function that (can) return a new
  57   allocation should behave this way; returning a tainted result if any tainted
  58   content is used.  Intermediate-layer functions (eg. Ustrncpy) that modify
  59   existing allocations fail if tainted data is written into an untainted area.
  60   Users of functions that modify existing allocations should check if a tainted
  61   source and an untainted destination is used, and fail instead (sprintf() being
  62   the classic case).
  63 */
  64
  65
  66 #include "exim.h"
  67 /* keep config.h before memcheck.h, for NVALGRIND */
  68 #include "config.h"
  69
  70 #include <sys/mman.h>
  71 #include "memcheck.h"
  72
  73
  74 /* We need to know how to align blocks of data for general use. I'm not sure
  75 how to get an alignment factor in general. In the current world, a value of 8
  76 is probably right, and this is sizeof(double) on some systems and sizeof(void
  77 *) on others, so take the larger of those. Since everything in this expression
  78 is a constant, the compiler should optimize it to a simple constant wherever it
  79 appears (I checked that gcc does do this). */
  80
  81 #define alignment \
  82   (sizeof(void *) > sizeof(double) ? sizeof(void *) : sizeof(double))
  83
  84 /* store_reset() will not free the following block if the last used block has
  85 less than this much left in it. */
  86
  87 #define STOREPOOL_MIN_SIZE 256
  88
  89 /* Structure describing the beginning of each big block. */
  90
  91 typedef struct storeblock {
  92   struct storeblock *next;
  93   size_t length;
  94 } storeblock;
  95
  96 /* Just in case we find ourselves on a system where the structure above has a
  97 length that is not a multiple of the alignment, set up a macro for the padded
  98 length. */
  99
 100 #define ALIGNED_SIZEOF_STOREBLOCK \
 101   (((sizeof(storeblock) + alignment - 1) / alignment) * alignment)
 102
 103 /* Size of block to get from malloc to carve up into smaller ones. This
 104 must be a multiple of the alignment. We assume that 8192 is going to be
 105 suitably aligned. */
 106
 107 #define STORE_BLOCK_SIZE (8192 - ALIGNED_SIZEOF_STOREBLOCK)
 108
 109 /* Variables holding data for the local pools of store. The current pool number
 110 is held in store_pool, which is global so that it can be changed from outside.
 111 Setting the initial length values to -1 forces a malloc for the first call,
 112 even if the length is zero (which is used for getting a point to reset to). */
 113
 114 int store_pool = POOL_MAIN;
 115
 116 #define NPOOLS 6
 117 static storeblock *chainbase[NPOOLS];
 118 static storeblock *current_block[NPOOLS];
 119 static void *next_yield[NPOOLS];
 120 static int yield_length[NPOOLS] = { -1, -1, -1,  -1, -1, -1 };
 121
 122 /* pool_malloc holds the amount of memory used by the store pools; this goes up
 123 and down as store is reset or released. nonpool_malloc is the total got by
 124 malloc from other calls; this doesn't go down because it is just freed by
 125 pointer. */
 126
 127 static int pool_malloc;
 128 static int nonpool_malloc;
 129
 130 /* This variable is set by store_get() to its yield, and by store_reset() to
 131 NULL. This enables string_cat() to optimize its store handling for very long
 132 strings. That's why the variable is global. */
 133
 134 void *store_last_get[NPOOLS];
 135
 136 /* These are purely for stats-gathering */
 137
 138 static int nbytes[NPOOLS];      /* current bytes allocated */
 139 static int maxbytes[NPOOLS];    /* max number reached */
 140 static int nblocks[NPOOLS];     /* current number of blocks allocated */
 141 static int maxblocks[NPOOLS];
 142 static int n_nonpool_blocks;    /* current number of direct store_malloc() blocks */
 143 static int max_nonpool_blocks;
 144 static int max_pool_malloc;     /* max value for pool_malloc */
 145 static int max_nonpool_malloc;  /* max value for nonpool_malloc */
 146
 147
 148 #ifndef COMPILE_UTILITY
 149 static const uschar * pooluse[NPOOLS] = {
 150 [POOL_MAIN] =           US"main",
 151 [POOL_PERM] =           US"perm",
 152 [POOL_SEARCH] =         US"search",
 153 [POOL_TAINT_MAIN] =     US"main",
 154 [POOL_TAINT_PERM] =     US"perm",
 155 [POOL_TAINT_SEARCH] =   US"search",
 156 };
 157 static const uschar * poolclass[NPOOLS] = {
 158 [POOL_MAIN] =           US"untainted",
 159 [POOL_PERM] =           US"untainted",
 160 [POOL_SEARCH] =         US"untainted",
 161 [POOL_TAINT_MAIN] =     US"tainted",
 162 [POOL_TAINT_PERM] =     US"tainted",
 163 [POOL_TAINT_SEARCH] =   US"tainted",
 164 };
 165 #endif
 166
 167
 168 static void * internal_store_malloc(int, const char *, int);
 169 static void   internal_store_free(void *, const char *, int linenumber);
 170
 171 /******************************************************************************/
 172
 173 /* Test if a pointer refers to tainted memory.
 174
 175 Slower version check, for use when platform intermixes malloc and mmap area
 176 addresses. Test against the current-block of all tainted pools first, then all
 177 blocks of all tainted pools.
 178
 179 Return: TRUE iff tainted
 180 */
 181
 182 BOOL
 183 is_tainted_fn(const void * p)
 184 {
 185 storeblock * b;
 186
 187 for (int pool = POOL_TAINT_BASE; pool < nelem(chainbase); pool++)
 188   if ((b = current_block[pool]))
 189     {
 190     uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
 191     if (US p >= bc && US p <= bc + b->length) return TRUE;
 192     }
 193
 194 for (int pool = POOL_TAINT_BASE; pool < nelem(chainbase); pool++)
 195   for (b = chainbase[pool]; b; b = b->next)
 196     {
 197     uschar * bc = US b + ALIGNED_SIZEOF_STOREBLOCK;
 198     if (US p >= bc && US p <= bc + b->length) return TRUE;
 199     }
 200 return FALSE;
 201 }
 202
 203
 204 void
 205 die_tainted(const uschar * msg, const uschar * func, int line)
 206 {
 207 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Taint mismatch, %s: %s %d\n",
 208         msg, func, line);
 209 }
 210
 211
 212
 213 /*************************************************
 214 *       Get a block from the current pool        *
 215 *************************************************/
 216
 217 /* Running out of store is a total disaster. This function is called via the
 218 macro store_get(). It passes back a block of store within the current big
 219 block, getting a new one if necessary. The address is saved in
 220 store_last_was_get.
 221
 222 Arguments:
 223   size        amount wanted, bytes
 224   tainted     class: set to true for untrusted data (eg. from smtp input)
 225   func        function from which called
 226   linenumber  line number in source file
 227
 228 Returns:      pointer to store (panic on malloc failure)
 229 */
 230
 231 void *
 232 store_get_3(int size, BOOL tainted, const char *func, int linenumber)
 233 {
 234 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
 235
 236 /* Round up the size to a multiple of the alignment. Although this looks a
 237 messy statement, because "alignment" is a constant expression, the compiler can
 238 do a reasonable job of optimizing, especially if the value of "alignment" is a
 239 power of two. I checked this with -O2, and gcc did very well, compiling it to 4
 240 instructions on a Sparc (alignment = 8). */
 241
 242 if (size % alignment != 0) size += alignment - (size % alignment);
 243
 244 /* If there isn't room in the current block, get a new one. The minimum
 245 size is STORE_BLOCK_SIZE, and we would expect this to be the norm, since
 246 these functions are mostly called for small amounts of store. */
 247
 248 if (size > yield_length[pool])
 249   {
 250   int length = size <= STORE_BLOCK_SIZE ? STORE_BLOCK_SIZE : size;
 251   int mlength = length + ALIGNED_SIZEOF_STOREBLOCK;
 252   storeblock * newblock;
 253
 254   /* Sometimes store_reset() may leave a block for us; check if we can use it */
 255
 256   if (  (newblock = current_block[pool])
 257      && (newblock = newblock->next)
 258      && newblock->length < length
 259      )
 260     {
 261     /* Give up on this block, because it's too small */
 262     nblocks[pool]--;
 263     internal_store_free(newblock, func, linenumber);
 264     newblock = NULL;
 265     }
 266
 267   /* If there was no free block, get a new one */
 268
 269   if (!newblock)
 270     {
 271     if ((nbytes[pool] += mlength) > maxbytes[pool])
 272       maxbytes[pool] = nbytes[pool];
 273     if ((pool_malloc += mlength) > max_pool_malloc)     /* Used in pools */
 274       max_pool_malloc = pool_malloc;
 275     nonpool_malloc -= mlength;                  /* Exclude from overall total */
 276     if (++nblocks[pool] > maxblocks[pool])
 277       maxblocks[pool] = nblocks[pool];
 278
 279     newblock = internal_store_malloc(mlength, func, linenumber);
 280     newblock->next = NULL;
 281     newblock->length = length;
 282
 283     if (!chainbase[pool])
 284       chainbase[pool] = newblock;
 285     else
 286       current_block[pool]->next = newblock;
 287     }
 288
 289   current_block[pool] = newblock;
 290   yield_length[pool] = newblock->length;
 291   next_yield[pool] =
 292     (void *)(CS current_block[pool] + ALIGNED_SIZEOF_STOREBLOCK);
 293   (void) VALGRIND_MAKE_MEM_NOACCESS(next_yield[pool], yield_length[pool]);
 294   }
 295
 296 /* There's (now) enough room in the current block; the yield is the next
 297 pointer. */
 298
 299 store_last_get[pool] = next_yield[pool];
 300
 301 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 302 giving warnings. */
 303
 304 #ifdef COMPILE_UTILITY
 305 func = func;
 306 linenumber = linenumber;
 307 #else
 308 DEBUG(D_memory)
 309   debug_printf("---%d Get %6p %5d %-14s %4d\n", pool,
 310     store_last_get[pool], size, func, linenumber);
 311 #endif  /* COMPILE_UTILITY */
 312
 313 (void) VALGRIND_MAKE_MEM_UNDEFINED(store_last_get[pool], size);
 314 /* Update next pointer and number of bytes left in the current block. */
 315
 316 next_yield[pool] = (void *)(CS next_yield[pool] + size);
 317 yield_length[pool] -= size;
 318 return store_last_get[pool];
 319 }
 320
 321
 322
 323 /*************************************************
 324 *       Get a block from the PERM pool           *
 325 *************************************************/
 326
 327 /* This is just a convenience function, useful when just a single block is to
 328 be obtained.
 329
 330 Arguments:
 331   size        amount wanted
 332   func        function from which called
 333   linenumber  line number in source file
 334
 335 Returns:      pointer to store (panic on malloc failure)
 336 */
 337
 338 void *
 339 store_get_perm_3(int size, BOOL tainted, const char *func, int linenumber)
 340 {
 341 void *yield;
 342 int old_pool = store_pool;
 343 store_pool = POOL_PERM;
 344 yield = store_get_3(size, tainted, func, linenumber);
 345 store_pool = old_pool;
 346 return yield;
 347 }
 348
 349
 350
 351 /*************************************************
 352 *      Extend a block if it is at the top        *
 353 *************************************************/
 354
 355 /* While reading strings of unknown length, it is often the case that the
 356 string is being read into the block at the top of the stack. If it needs to be
 357 extended, it is more efficient just to extend within the top block rather than
 358 allocate a new block and then have to copy the data. This function is provided
 359 for the use of string_cat(), but of course can be used elsewhere too.
 360 The block itself is not expanded; only the top allocation from it.
 361
 362 Arguments:
 363   ptr        pointer to store block
 364   oldsize    current size of the block, as requested by user
 365   newsize    new size required
 366   func       function from which called
 367   linenumber line number in source file
 368
 369 Returns:     TRUE if the block is at the top of the stack and has been
 370              extended; FALSE if it isn't at the top of the stack, or cannot
 371              be extended
 372 */
 373
 374 BOOL
 375 store_extend_3(void *ptr, BOOL tainted, int oldsize, int newsize,
 376    const char *func, int linenumber)
 377 {
 378 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
 379 int inc = newsize - oldsize;
 380 int rounded_oldsize = oldsize;
 381
 382 /* Check that the block being extended was already of the required taint status;
 383 refuse to extend if not. */
 384
 385 if (is_tainted(ptr) != tainted)
 386   return FALSE;
 387
 388 if (rounded_oldsize % alignment != 0)
 389   rounded_oldsize += alignment - (rounded_oldsize % alignment);
 390
 391 if (CS ptr + rounded_oldsize != CS (next_yield[pool]) ||
 392     inc > yield_length[pool] + rounded_oldsize - oldsize)
 393   return FALSE;
 394
 395 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 396 giving warnings. */
 397
 398 #ifdef COMPILE_UTILITY
 399 func = func;
 400 linenumber = linenumber;
 401 #else
 402 DEBUG(D_memory)
 403   debug_printf("---%d Ext %6p %5d %-14s %4d\n", pool, ptr, newsize,
 404     func, linenumber);
 405 #endif  /* COMPILE_UTILITY */
 406
 407 if (newsize % alignment != 0) newsize += alignment - (newsize % alignment);
 408 next_yield[pool] = CS ptr + newsize;
 409 yield_length[pool] -= newsize - rounded_oldsize;
 410 (void) VALGRIND_MAKE_MEM_UNDEFINED(ptr + oldsize, inc);
 411 return TRUE;
 412 }
 413
 414
 415
 416
 417 /*************************************************
 418 *    Back up to a previous point on the stack    *
 419 *************************************************/
 420
 421 /* This function resets the next pointer, freeing any subsequent whole blocks
 422 that are now unused. Call with a cookie obtained from store_mark() only; do
 423 not call with a pointer returned by store_get().  Both the untainted and tainted
 424 pools corresposding to store_pool are reset.
 425
 426 Arguments:
 427   r           place to back up to
 428   func        function from which called
 429   linenumber  line number in source file
 430
 431 Returns:      nothing
 432 */
 433
 434 static void
 435 internal_store_reset(void * ptr, int pool, const char *func, int linenumber)
 436 {
 437 storeblock * bb;
 438 storeblock * b = current_block[pool];
 439 char * bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 440 int newlength, count;
 441 #ifndef COMPILE_UTILITY
 442 int oldmalloc = pool_malloc;
 443 #endif
 444
 445 /* Last store operation was not a get */
 446
 447 store_last_get[pool] = NULL;
 448
 449 /* See if the place is in the current block - as it often will be. Otherwise,
 450 search for the block in which it lies. */
 451
 452 if (CS ptr < bc || CS ptr > bc + b->length)
 453   {
 454   for (b = chainbase[pool]; b; b = b->next)
 455     {
 456     bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 457     if (CS ptr >= bc && CS ptr <= bc + b->length) break;
 458     }
 459   if (!b)
 460     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "internal error: store_reset(%p) "
 461       "failed: pool=%d %-14s %4d", ptr, pool, func, linenumber);
 462   }
 463
 464 /* Back up, rounding to the alignment if necessary. When testing, flatten
 465 the released memory. */
 466
 467 newlength = bc + b->length - CS ptr;
 468 #ifndef COMPILE_UTILITY
 469 if (debug_store)
 470   {
 471   assert_no_variables(ptr, newlength, func, linenumber);
 472   if (f.running_in_test_harness)
 473     {
 474     (void) VALGRIND_MAKE_MEM_DEFINED(ptr, newlength);
 475     memset(ptr, 0xF0, newlength);
 476     }
 477   }
 478 #endif
 479 (void) VALGRIND_MAKE_MEM_NOACCESS(ptr, newlength);
 480 next_yield[pool] = CS ptr + (newlength % alignment);
 481 count = yield_length[pool];
 482 count = (yield_length[pool] = newlength - (newlength % alignment)) - count;
 483 current_block[pool] = b;
 484
 485 /* Free any subsequent block. Do NOT free the first
 486 successor, if our current block has less than 256 bytes left. This should
 487 prevent us from flapping memory. However, keep this block only when it has
 488 the default size. */
 489
 490 if (  yield_length[pool] < STOREPOOL_MIN_SIZE
 491    && b->next
 492    && b->next->length == STORE_BLOCK_SIZE)
 493   {
 494   b = b->next;
 495 #ifndef COMPILE_UTILITY
 496   if (debug_store)
 497     assert_no_variables(b, b->length + ALIGNED_SIZEOF_STOREBLOCK,
 498                         func, linenumber);
 499 #endif
 500   (void) VALGRIND_MAKE_MEM_NOACCESS(CS b + ALIGNED_SIZEOF_STOREBLOCK,
 501                 b->length - ALIGNED_SIZEOF_STOREBLOCK);
 502   }
 503
 504 bb = b->next;
 505 b->next = NULL;
 506
 507 while ((b = bb))
 508   {
 509   int siz = b->length + ALIGNED_SIZEOF_STOREBLOCK;
 510 #ifndef COMPILE_UTILITY
 511   if (debug_store)
 512     assert_no_variables(b, b->length + ALIGNED_SIZEOF_STOREBLOCK,
 513                         func, linenumber);
 514 #endif
 515   bb = bb->next;
 516   nbytes[pool] -= siz;
 517   pool_malloc -= siz;
 518   nblocks[pool]--;
 519   internal_store_free(b, func, linenumber);
 520   }
 521
 522 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 523 giving warnings. */
 524
 525 #ifdef COMPILE_UTILITY
 526 func = func;
 527 linenumber = linenumber;
 528 #else
 529 DEBUG(D_memory)
 530   debug_printf("---%d Rst %6p %5d %-14s %4d %d\n", pool, ptr,
 531     count + oldmalloc - pool_malloc,
 532     func, linenumber, pool_malloc);
 533 #endif  /* COMPILE_UTILITY */
 534 }
 535
 536
 537 rmark
 538 store_reset_3(rmark r, int pool, const char *func, int linenumber)
 539 {
 540 void ** ptr = r;
 541
 542 if (pool >= POOL_TAINT_BASE)
 543   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
 544     "store_reset called for pool %d: %s %d\n", pool, func, linenumber);
 545 if (!r)
 546   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
 547     "store_reset called with bad mark: %s %d\n", func, linenumber);
 548
 549 internal_store_reset(*ptr, pool + POOL_TAINT_BASE, func, linenumber);
 550 internal_store_reset(ptr,  pool,                   func, linenumber);
 551 return NULL;
 552 }
 553
 554
 555
 556 /* Free tail-end unused allocation.  This lets us allocate a big chunk
 557 early, for cases when we only discover later how much was really needed.
 558
 559 Can be called with a value from store_get(), or an offset after such.  Only
 560 the tainted or untainted pool that serviced the store_get() will be affected.
 561
 562 This is mostly a cut-down version of internal_store_reset().
 563 XXX needs rationalising
 564 */
 565
 566 void
 567 store_release_above_3(void *ptr, const char *func, int linenumber)
 568 {
 569 /* Search all pools' "current" blocks.  If it isn't one of those,
 570 ignore it (it usually will be). */
 571
 572 for (int pool = 0; pool < nelem(current_block); pool++)
 573   {
 574   storeblock * b = current_block[pool];
 575   char * bc;
 576   int count, newlength;
 577
 578   if (!b)
 579     continue;
 580
 581   bc = CS b + ALIGNED_SIZEOF_STOREBLOCK;
 582   if (CS ptr < bc || CS ptr > bc + b->length)
 583     continue;
 584
 585   /* Last store operation was not a get */
 586
 587   store_last_get[pool] = NULL;
 588
 589   /* Back up, rounding to the alignment if necessary. When testing, flatten
 590   the released memory. */
 591
 592   newlength = bc + b->length - CS ptr;
 593 #ifndef COMPILE_UTILITY
 594   if (debug_store)
 595     {
 596     assert_no_variables(ptr, newlength, func, linenumber);
 597     if (f.running_in_test_harness)
 598       {
 599       (void) VALGRIND_MAKE_MEM_DEFINED(ptr, newlength);
 600       memset(ptr, 0xF0, newlength);
 601       }
 602     }
 603 #endif
 604   (void) VALGRIND_MAKE_MEM_NOACCESS(ptr, newlength);
 605   next_yield[pool] = CS ptr + (newlength % alignment);
 606   count = yield_length[pool];
 607   count = (yield_length[pool] = newlength - (newlength % alignment)) - count;
 608
 609   /* Cut out the debugging stuff for utilities, but stop picky compilers from
 610   giving warnings. */
 611
 612 #ifdef COMPILE_UTILITY
 613   func = func;
 614   linenumber = linenumber;
 615 #else
 616   DEBUG(D_memory)
 617     debug_printf("---%d Rel %6p %5d %-14s %4d %d\n", pool, ptr, count,
 618       func, linenumber, pool_malloc);
 619 #endif
 620   return;
 621   }
 622 #ifndef COMPILE_UTILITY
 623 DEBUG(D_memory)
 624   debug_printf("non-last memory release try: %s %d\n", func, linenumber);
 625 #endif
 626 }
 627
 628
 629
 630 rmark
 631 store_mark_3(const char *func, int linenumber)
 632 {
 633 void ** p;
 634
 635 if (store_pool >= POOL_TAINT_BASE)
 636   log_write(0, LOG_MAIN|LOG_PANIC_DIE,
 637     "store_mark called for pool %d: %s %d\n", store_pool, func, linenumber);
 638
 639 /* Stash a mark for the tainted-twin release, in the untainted twin. Return
 640 a cookie (actually the address in the untainted pool) to the caller.
 641 Reset uses the cookie to recover the t-mark, winds back the tainted pool with it
 642 and winds back the untainted pool with the cookie. */
 643
 644 p = store_get_3(sizeof(void *), FALSE, func, linenumber);
 645 *p = store_get_3(0, TRUE, func, linenumber);
 646 return p;
 647 }
 648
 649
 650
 651
 652 /************************************************
 653 *             Release store                     *
 654 ************************************************/
 655
 656 /* This function checks that the pointer it is given is the first thing in a
 657 block, and if so, releases that block.
 658
 659 Arguments:
 660   block       block of store to consider
 661   func        function from which called
 662   linenumber  line number in source file
 663
 664 Returns:      nothing
 665 */
 666
 667 static void
 668 store_release_3(void * block, int pool, const char * func, int linenumber)
 669 {
 670 /* It will never be the first block, so no need to check that. */
 671
 672 for (storeblock * b = chainbase[pool]; b; b = b->next)
 673   {
 674   storeblock * bb = b->next;
 675   if (bb && CS block == CS bb + ALIGNED_SIZEOF_STOREBLOCK)
 676     {
 677     int siz = bb->length + ALIGNED_SIZEOF_STOREBLOCK;
 678     b->next = bb->next;
 679     nbytes[pool] -= siz;
 680     pool_malloc -= siz;
 681     nblocks[pool]--;
 682
 683     /* Cut out the debugging stuff for utilities, but stop picky compilers
 684     from giving warnings. */
 685
 686 #ifdef COMPILE_UTILITY
 687     func = func;
 688     linenumber = linenumber;
 689 #else
 690     DEBUG(D_memory)
 691       debug_printf("-Release %6p %-20s %4d %d\n", (void *)bb, func,
 692         linenumber, pool_malloc);
 693
 694     if (f.running_in_test_harness)
 695       memset(bb, 0xF0, bb->length+ALIGNED_SIZEOF_STOREBLOCK);
 696 #endif  /* COMPILE_UTILITY */
 697
 698     free(bb);
 699     return;
 700     }
 701   }
 702 }
 703
 704
 705 /************************************************
 706 *             Move store                        *
 707 ************************************************/
 708
 709 /* Allocate a new block big enough to expend to the given size and
 710 copy the current data into it.  Free the old one if possible.
 711
 712 This function is specifically provided for use when reading very
 713 long strings, e.g. header lines. When the string gets longer than a
 714 complete block, it gets copied to a new block. It is helpful to free
 715 the old block iff the previous copy of the string is at its start,
 716 and therefore the only thing in it. Otherwise, for very long strings,
 717 dead store can pile up somewhat disastrously. This function checks that
 718 the pointer it is given is the first thing in a block, and that nothing
 719 has been allocated since. If so, releases that block.
 720
 721 Arguments:
 722   block
 723   newsize
 724   len
 725
 726 Returns:        new location of data
 727 */
 728
 729 void *
 730 store_newblock_3(void * block, BOOL tainted, int newsize, int len,
 731   const char * func, int linenumber)
 732 {
 733 int pool = tainted ? store_pool + POOL_TAINT_BASE : store_pool;
 734 BOOL release_ok = !tainted && store_last_get[pool] == block;
 735 uschar * newtext;
 736
 737 #if !defined(MACRO_PREDEF) && !defined(COMPILE_UTILITY)
 738 if (is_tainted(block) != tainted)
 739   die_tainted(US"store_newblock", CUS func, linenumber);
 740 #endif
 741
 742 newtext = store_get(newsize, tainted);
 743 memcpy(newtext, block, len);
 744 if (release_ok) store_release_3(block, pool, func, linenumber);
 745 return (void *)newtext;
 746 }
 747
 748
 749
 750
 751 /*************************************************
 752 *                Malloc store                    *
 753 *************************************************/
 754
 755 /* Running out of store is a total disaster for exim. Some malloc functions
 756 do not run happily on very small sizes, nor do they document this fact. This
 757 function is called via the macro store_malloc().
 758
 759 Arguments:
 760   size        amount of store wanted
 761   func        function from which called
 762   line        line number in source file
 763
 764 Returns:      pointer to gotten store (panic on failure)
 765 */
 766
 767 static void *
 768 internal_store_malloc(int size, const char *func, int line)
 769 {
 770 void * yield;
 771
 772 if (size < 16) size = 16;
 773
 774 if (!(yield = malloc((size_t)size)))
 775   log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to malloc %d bytes of memory: "
 776     "called from line %d in %s", size, line, func);
 777
 778 if ((nonpool_malloc += size) > max_nonpool_malloc)
 779   max_nonpool_malloc = nonpool_malloc;
 780
 781 /* Cut out the debugging stuff for utilities, but stop picky compilers from
 782 giving warnings. */
 783
 784 #ifdef COMPILE_UTILITY
 785 func = func; line = line;
 786 #else
 787
 788 /* If running in test harness, spend time making sure all the new store
 789 is not filled with zeros so as to catch problems. */
 790
 791 if (f.running_in_test_harness)
 792   memset(yield, 0xF0, (size_t)size);
 793 DEBUG(D_memory) debug_printf("--Malloc %6p %5d bytes\t%-14s %4d\tpool %5d  nonpool %5d\n",
 794   yield, size, func, line, pool_malloc, nonpool_malloc);
 795 #endif  /* COMPILE_UTILITY */
 796
 797 return yield;
 798 }
 799
 800 void *
 801 store_malloc_3(int size, const char *func, int linenumber)
 802 {
 803 if (n_nonpool_blocks++ > max_nonpool_blocks)
 804   max_nonpool_blocks = n_nonpool_blocks;
 805 return internal_store_malloc(size, func, linenumber);
 806 }
 807
 808
 809 /************************************************
 810 *             Free store                        *
 811 ************************************************/
 812
 813 /* This function is called by the macro store_free().
 814
 815 Arguments:
 816   block       block of store to free
 817   func        function from which called
 818   linenumber  line number in source file
 819
 820 Returns:      nothing
 821 */
 822
 823 static void
 824 internal_store_free(void * block, const char * func, int linenumber)
 825 {
 826 #ifdef COMPILE_UTILITY
 827 func = func;
 828 linenumber = linenumber;
 829 #else
 830 DEBUG(D_memory)
 831   debug_printf("----Free %6p %-20s %4d\n", block, func, linenumber);
 832 #endif  /* COMPILE_UTILITY */
 833 free(block);
 834 }
 835
 836 void
 837 store_free_3(void * block, const char * func, int linenumber)
 838 {
 839 n_nonpool_blocks--;
 840 internal_store_free(block, func, linenumber);
 841 }
 842
 843 /******************************************************************************/
 844 /* Stats output on process exit */
 845 void
 846 store_exit(void)
 847 {
 848 #ifndef COMPILE_UTILITY
 849 DEBUG(D_memory)
 850  {
 851  debug_printf("----Exit nonpool max: %3d kB in %d blocks\n",
 852   (max_nonpool_malloc+1023)/1024, max_nonpool_blocks);
 853  debug_printf("----Exit npools  max: %3d kB\n", max_pool_malloc/1024);
 854  for (int i = 0; i < NPOOLS; i++)
 855   debug_printf("----Exit  pool %d max: %3d kB in %d blocks\t%s %s\n",
 856     i, maxbytes[i]/1024, maxblocks[i], poolclass[i], pooluse[i]);
 857  }
 858 #endif
 859 }
 860
 861 /* End of store.c */