source3/lib/talloc.c

   1 /*
   2    Samba Unix SMB/CIFS implementation.
   3    Samba temporary memory allocation functions
   4    Copyright (C) Andrew Tridgell 2000
   5    Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 /**
  23    @defgroup talloc Simple memory allocator
  24    @{
  25
  26    This is a very simple temporary memory allocator. To use it do the following:
  27
  28    1) when you first want to allocate a pool of meomry use
  29    talloc_init() and save the resulting context pointer somewhere
  30
  31    2) to allocate memory use talloc()
  32
  33    3) when _all_ of the memory allocated using this context is no longer needed
  34    use talloc_destroy()
  35
  36    talloc does not zero the memory. It guarantees memory of a
  37    TALLOC_ALIGN alignment
  38
  39    @sa talloc.h
  40 */
  41
  42 /**
  43  * @todo We could allocate both the talloc_chunk structure, and the
  44  * memory it contains all in one allocation, which might be a bit
  45  * faster and perhaps use less memory overhead.
  46  *
  47  * That smells like a premature optimization, though.  -- mbp
  48  **/
  49
  50 /**
  51  * If you want testing for memory corruption, link with dmalloc or use
  52  * Insure++.  It doesn't seem useful to duplicate them here.
  53  **/
  54
  55 #include "includes.h"
  56
  57 struct talloc_chunk {
  58         struct talloc_chunk *next;
  59         size_t size;
  60         void *ptr;
  61 };
  62
  63
  64 struct talloc_ctx {
  65         struct talloc_chunk *list;
  66         size_t total_alloc_size;
  67
  68         /** The name recorded for this pool, if any.  Should describe
  69          * the purpose for which it was allocated.  The string is
  70          * allocated within the pool. **/
  71         char *name;
  72
  73         /** Pointer to the next allocate talloc pool, so that we can
  74          * summarize all talloc memory usage. **/
  75         struct talloc_ctx *next_ctx;
  76 };
  77
  78
  79 /**
  80  * Start of linked list of all talloc pools.
  81  *
  82  * @todo We should turn the global list off when using Insure++,
  83  * otherwise all the memory will be seen as still reachable.
  84  **/
  85 static TALLOC_CTX *list_head = NULL;
  86
  87
  88 /**
  89  * Add to the global list
  90  **/
  91 static void talloc_enroll(TALLOC_CTX *t)
  92 {
  93         t->next_ctx = list_head;
  94         list_head = t;
  95 }
  96
  97
  98 static void talloc_disenroll(TALLOC_CTX *t)
  99 {
 100         TALLOC_CTX **ttmp;
 101
 102         /* Use a double-* so that no special case is required for the
 103          * list head. */
 104         for (ttmp = &list_head; *ttmp; ttmp = &((*ttmp)->next_ctx))
 105                 if (*ttmp == t) {
 106                         /* ttmp is the link that points to t, either
 107                          * list_head or the next_ctx link in its
 108                          * predecessor */
 109                         *ttmp = t->next_ctx;
 110                         t->next_ctx = NULL;     /* clobber */
 111                         return;
 112                 }
 113         abort();                /* oops, this talloc was already
 114                                  * clobbered or something else went
 115                                  * wrong. */
 116 }
 117
 118
 119 /** Create a new talloc context. **/
 120 static TALLOC_CTX *talloc_init_internal(void)
 121 {
 122         TALLOC_CTX *t;
 123
 124         t = (TALLOC_CTX *)malloc(sizeof(TALLOC_CTX));
 125         if (t) {
 126                 t->list = NULL;
 127                 t->total_alloc_size = 0;
 128                 t->name = NULL;
 129                 talloc_enroll(t);
 130         }
 131
 132         return t;
 133 }
 134
 135
 136
 137 /**
 138  * Create a new talloc context, with a name specifying its purpose.
 139  **/
 140
 141  TALLOC_CTX *talloc_init(char const *fmt, ...)
 142 {
 143         TALLOC_CTX *t;
 144         va_list ap;
 145
 146         t = talloc_init_internal();
 147         if (t && fmt) {
 148                 /*
 149                  * t->name must not be talloced.
 150                  * as destroying the pool would destroy it. JRA.
 151                  */
 152                 t->name = NULL;
 153                 va_start(ap, fmt);
 154                 vasprintf(&t->name, fmt, ap);
 155                 va_end(ap);
 156                 if (!t->name) {
 157                         talloc_destroy(t);
 158                         t = NULL;
 159                 }
 160         }
 161
 162         return t;
 163 }
 164
 165
 166 /** Allocate a bit of memory from the specified pool **/
 167 void *talloc(TALLOC_CTX *t, size_t size)
 168 {
 169         void *p;
 170         struct talloc_chunk *tc;
 171
 172         if (!t || size == 0) return NULL;
 173
 174         p = malloc(size);
 175         if (p) {
 176                 tc = malloc(sizeof(*tc));
 177                 if (tc) {
 178                         tc->ptr = p;
 179                         tc->size = size;
 180                         tc->next = t->list;
 181                         t->list = tc;
 182                         t->total_alloc_size += size;
 183                 }
 184                 else {
 185                         SAFE_FREE(p);
 186                 }
 187         }
 188         return p;
 189 }
 190
 191 /** A talloc version of realloc */
 192 void *talloc_realloc(TALLOC_CTX *t, void *ptr, size_t size)
 193 {
 194         struct talloc_chunk *tc;
 195         void *new_ptr;
 196
 197         /* size zero is equivalent to free() */
 198         if (!t || size == 0)
 199                 return NULL;
 200
 201         /* realloc(NULL) is equavalent to malloc() */
 202         if (ptr == NULL)
 203                 return talloc(t, size);
 204
 205         for (tc=t->list; tc; tc=tc->next) {
 206                 if (tc->ptr == ptr) {
 207                         new_ptr = Realloc(ptr, size);
 208                         if (new_ptr) {
 209                                 t->total_alloc_size += (size - tc->size);
 210                                 tc->size = size;
 211                                 tc->ptr = new_ptr;
 212                         }
 213                         return new_ptr;
 214                 }
 215         }
 216         return NULL;
 217 }
 218
 219 /** Destroy all the memory allocated inside @p t, but not @p t
 220  * itself. */
 221 void talloc_destroy_pool(TALLOC_CTX *t)
 222 {
 223         struct talloc_chunk *c;
 224
 225         if (!t)
 226                 return;
 227
 228         while (t->list) {
 229                 c = t->list->next;
 230                 SAFE_FREE(t->list->ptr);
 231                 SAFE_FREE(t->list);
 232                 t->list = c;
 233         }
 234
 235         t->total_alloc_size = 0;
 236 }
 237
 238 /** Destroy a whole pool including the context */
 239 void talloc_destroy(TALLOC_CTX *t)
 240 {
 241         if (!t)
 242                 return;
 243
 244         talloc_destroy_pool(t);
 245         talloc_disenroll(t);
 246         SAFE_FREE(t->name);
 247         memset(t, 0, sizeof(TALLOC_CTX));
 248         SAFE_FREE(t);
 249 }
 250
 251 /** Return the current total size of the pool. */
 252 size_t talloc_pool_size(TALLOC_CTX *t)
 253 {
 254         if (t)
 255                 return t->total_alloc_size;
 256         else
 257                 return 0;
 258 }
 259
 260 const char * talloc_pool_name(TALLOC_CTX const *t)
 261 {
 262         if (t)
 263                 return t->name;
 264         else
 265                 return NULL;
 266 }
 267
 268
 269 /** talloc and zero memory. */
 270 void *talloc_zero(TALLOC_CTX *t, size_t size)
 271 {
 272         void *p = talloc(t, size);
 273
 274         if (p)
 275                 memset(p, '\0', size);
 276
 277         return p;
 278 }
 279
 280 /** memdup with a talloc. */
 281 void *talloc_memdup(TALLOC_CTX *t, const void *p, size_t size)
 282 {
 283         void *newp = talloc(t,size);
 284
 285         if (newp)
 286                 memcpy(newp, p, size);
 287
 288         return newp;
 289 }
 290
 291 /** strdup with a talloc */
 292 char *talloc_strdup(TALLOC_CTX *t, const char *p)
 293 {
 294         if (p)
 295                 return talloc_memdup(t, p, strlen(p) + 1);
 296         else
 297                 return NULL;
 298 }
 299
 300 /** strdup_w with a talloc */
 301 smb_ucs2_t *talloc_strdup_w(TALLOC_CTX *t, const smb_ucs2_t *p)
 302 {
 303         if (p)
 304                 return talloc_memdup(t, p, (strlen_w(p) + 1) * sizeof(smb_ucs2_t));
 305         else
 306                 return NULL;
 307 }
 308
 309 /**
 310  * Perform string formatting, and return a pointer to newly allocated
 311  * memory holding the result, inside a memory pool.
 312  **/
 313  char *talloc_asprintf(TALLOC_CTX *t, const char *fmt, ...)
 314 {
 315         va_list ap;
 316         char *ret;
 317
 318         va_start(ap, fmt);
 319         ret = talloc_vasprintf(t, fmt, ap);
 320         va_end(ap);
 321         return ret;
 322 }
 323
 324
 325  char *talloc_vasprintf(TALLOC_CTX *t, const char *fmt, va_list ap)
 326 {
 327         int len;
 328         char *ret;
 329         va_list ap2;
 330
 331         VA_COPY(ap2, ap);
 332
 333         len = vsnprintf(NULL, 0, fmt, ap2);
 334
 335         ret = talloc(t, len+1);
 336         if (ret) {
 337                 VA_COPY(ap2, ap);
 338                 vsnprintf(ret, len+1, fmt, ap2);
 339         }
 340
 341         return ret;
 342 }
 343
 344
 345 /**
 346  * Realloc @p s to append the formatted result of @p fmt and return @p
 347  * s, which may have moved.  Good for gradually accumulating output
 348  * into a string buffer.
 349  **/
 350  char *talloc_asprintf_append(TALLOC_CTX *t, char *s,
 351                               const char *fmt, ...)
 352 {
 353         va_list ap;
 354
 355         va_start(ap, fmt);
 356         s = talloc_vasprintf_append(t, s, fmt, ap);
 357         va_end(ap);
 358         return s;
 359 }
 360
 361
 362
 363 /**
 364  * Realloc @p s to append the formatted result of @p fmt and @p ap,
 365  * and return @p s, which may have moved.  Good for gradually
 366  * accumulating output into a string buffer.
 367  **/
 368  char *talloc_vasprintf_append(TALLOC_CTX *t, char *s,
 369                                const char *fmt, va_list ap)
 370 {
 371         int len, s_len;
 372         va_list ap2;
 373
 374         VA_COPY(ap2, ap);
 375
 376         s_len = strlen(s);
 377         len = vsnprintf(NULL, 0, fmt, ap2);
 378
 379         s = talloc_realloc(t, s, s_len + len+1);
 380         if (!s) return NULL;
 381
 382         VA_COPY(ap2, ap);
 383
 384         vsnprintf(s+s_len, len+1, fmt, ap2);
 385
 386         return s;
 387 }
 388
 389
 390 /**
 391  * Return a human-readable description of all talloc memory usage.
 392  * The result is allocated from @p t.
 393  **/
 394 char *talloc_describe_all(TALLOC_CTX *rt)
 395 {
 396         int n_pools = 0, total_chunks = 0;
 397         size_t total_bytes = 0;
 398         TALLOC_CTX *it;
 399         char *s;
 400
 401         if (!rt) return NULL;
 402
 403         s = talloc_asprintf(rt, "global talloc allocations in pid: %u\n",
 404                             (unsigned) sys_getpid());
 405         s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
 406                                    "name", "chunks", "bytes");
 407         s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
 408                                    "----------------------------------------",
 409                                    "--------",
 410                                    "--------");
 411
 412         for (it = list_head; it; it = it->next_ctx) {
 413                 size_t bytes;
 414                 int n_chunks;
 415                 fstring what;
 416
 417                 n_pools++;
 418
 419                 talloc_get_allocation(it, &bytes, &n_chunks);
 420
 421                 if (it->name)
 422                         fstrcpy(what, it->name);
 423                 else
 424                         slprintf(what, sizeof(what), "@%p", it);
 425
 426                 s = talloc_asprintf_append(rt, s, "%-40s %8u %8u\n",
 427                                            what,
 428                                            (unsigned) n_chunks,
 429                                            (unsigned) bytes);
 430                 total_bytes += bytes;
 431                 total_chunks += n_chunks;
 432         }
 433
 434         s = talloc_asprintf_append(rt, s, "%-40s %8s %8s\n",
 435                                    "----------------------------------------",
 436                                    "--------",
 437                                    "--------");
 438
 439         s = talloc_asprintf_append(rt, s, "%-40s %8u %8u\n",
 440                                    "TOTAL",
 441                                    (unsigned) total_chunks, (unsigned) total_bytes);
 442
 443         return s;
 444 }
 445
 446
 447
 448 /**
 449  * Return an estimated memory usage for the specified pool.  This does
 450  * not include memory used by the underlying malloc implementation.
 451  **/
 452 void talloc_get_allocation(TALLOC_CTX *t,
 453                            size_t *total_bytes,
 454                            int *n_chunks)
 455 {
 456         struct talloc_chunk *chunk;
 457
 458         if (t) {
 459                 *total_bytes = 0;
 460                 *n_chunks = 0;
 461
 462                 for (chunk = t->list; chunk; chunk = chunk->next) {
 463                         n_chunks[0]++;
 464                         *total_bytes += chunk->size;
 465                 }
 466         }
 467 }
 468
 469
 470 /** @} */