unbound/util/regional.c

   1 /*
   2  * regional.c -- region based memory allocator.
   3  *
   4  * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
   5  *
   6  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   7  *
   8  * This software is open source.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  * Redistributions of source code must retain the above copyright notice,
  15  * this list of conditions and the following disclaimer.
  16  *
  17  * Redistributions in binary form must reproduce the above copyright notice,
  18  * this list of conditions and the following disclaimer in the documentation
  19  * and/or other materials provided with the distribution.
  20  *
  21  * Neither the name of the NLNET LABS nor the names of its contributors may
  22  * be used to endorse or promote products derived from this software without
  23  * specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  31  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  32  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  33  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  34  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  35  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 /**
  39  * \file
  40  * Regional allocator. Allocates small portions of of larger chunks.
  41  */
  42
  43 #include "config.h"
  44 #include "util/log.h"
  45 #include "util/regional.h"
  46
  47 #ifdef ALIGNMENT
  48 #  undef ALIGNMENT
  49 #endif
  50 /** increase size until it fits alignment of s bytes */
  51 #define ALIGN_UP(x, s)     (((x) + s - 1) & (~(s - 1)))
  52 /** what size to align on; make sure a char* fits in it. */
  53 #define ALIGNMENT          (sizeof(uint64_t))
  54
  55 /** Default reasonable size for chunks */
  56 #define REGIONAL_CHUNK_SIZE         8192
  57 #ifdef UNBOUND_ALLOC_NONREGIONAL
  58 /** All objects allocated outside of chunks, for debug */
  59 #define REGIONAL_LARGE_OBJECT_SIZE  0
  60 #else
  61 /** Default size for large objects - allocated outside of chunks. */
  62 #define REGIONAL_LARGE_OBJECT_SIZE  2048
  63 #endif
  64
  65 struct regional*
  66 regional_create(void)
  67 {
  68         return regional_create_custom(REGIONAL_CHUNK_SIZE);
  69 }
  70
  71 /** init regional struct with first block */
  72 static void
  73 regional_init(struct regional* r)
  74 {
  75         size_t a = ALIGN_UP(sizeof(struct regional), ALIGNMENT);
  76         r->data = (char*)r + a;
  77         r->available = r->first_size - a;
  78         r->next = NULL;
  79         r->large_list = NULL;
  80         r->total_large = 0;
  81 }
  82
  83 struct regional*
  84 regional_create_custom(size_t size)
  85 {
  86         struct regional* r = (struct regional*)malloc(size);
  87         log_assert(sizeof(struct regional) <= size);
  88         if(!r) return NULL;
  89         r->first_size = size;
  90         regional_init(r);
  91         return r;
  92 }
  93
  94 void
  95 regional_free_all(struct regional *r)
  96 {
  97         char* p = r->next, *np;
  98         while(p) {
  99                 np = *(char**)p;
 100                 free(p);
 101                 p = np;
 102         }
 103         p = r->large_list;
 104         while(p) {
 105                 np = *(char**)p;
 106                 free(p);
 107                 p = np;
 108         }
 109         regional_init(r);
 110 }
 111
 112 void
 113 regional_destroy(struct regional *r)
 114 {
 115         if(!r) return;
 116         regional_free_all(r);
 117         free(r);
 118 }
 119
 120 void *
 121 regional_alloc(struct regional *r, size_t size)
 122 {
 123         size_t a = ALIGN_UP(size, ALIGNMENT);
 124         void *s;
 125         /* large objects */
 126         if(a > REGIONAL_LARGE_OBJECT_SIZE) {
 127                 s = malloc(ALIGNMENT + size);
 128                 if(!s) return NULL;
 129                 r->total_large += ALIGNMENT+size;
 130                 *(char**)s = r->large_list;
 131                 r->large_list = (char*)s;
 132                 return (char*)s+ALIGNMENT;
 133         }
 134         /* create a new chunk */
 135         if(a > r->available) {
 136                 s = malloc(REGIONAL_CHUNK_SIZE);
 137                 if(!s) return NULL;
 138                 *(char**)s = r->next;
 139                 r->next = (char*)s;
 140                 r->data = (char*)s + ALIGNMENT;
 141                 r->available = REGIONAL_CHUNK_SIZE - ALIGNMENT;
 142         }
 143         /* put in this chunk */
 144         r->available -= a;
 145         s = r->data;
 146         r->data += a;
 147         return s;
 148 }
 149
 150 void *
 151 regional_alloc_init(struct regional* r, const void *init, size_t size)
 152 {
 153         void *s = regional_alloc(r, size);
 154         if(!s) return NULL;
 155         memcpy(s, init, size);
 156         return s;
 157 }
 158
 159 void *
 160 regional_alloc_zero(struct regional *r, size_t size)
 161 {
 162         void *s = regional_alloc(r, size);
 163         if(!s) return NULL;
 164         memset(s, 0, size);
 165         return s;
 166 }
 167
 168 char *
 169 regional_strdup(struct regional *r, const char *string)
 170 {
 171         return (char*)regional_alloc_init(r, string, strlen(string)+1);
 172 }
 173
 174 /**
 175  * reasonably slow, but stats and get_mem are not supposed to be fast
 176  * count the number of chunks in use
 177  */
 178 static size_t
 179 count_chunks(struct regional* r)
 180 {
 181         size_t c = 1;
 182         char* p = r->next;
 183         while(p) {
 184                 c++;
 185                 p = *(char**)p;
 186         }
 187         return c;
 188 }
 189
 190 /**
 191  * also reasonably slow, counts the number of large objects
 192  */
 193 static size_t
 194 count_large(struct regional* r)
 195 {
 196         size_t c = 0;
 197         char* p = r->large_list;
 198         while(p) {
 199                 c++;
 200                 p = *(char**)p;
 201         }
 202         return c;
 203 }
 204
 205 void
 206 regional_log_stats(struct regional *r)
 207 {
 208         /* some basic assertions put here (non time critical code) */
 209         log_assert(ALIGNMENT >= sizeof(char*));
 210         log_assert(REGIONAL_CHUNK_SIZE > ALIGNMENT);
 211         log_assert(REGIONAL_CHUNK_SIZE-ALIGNMENT > REGIONAL_LARGE_OBJECT_SIZE);
 212         log_assert(REGIONAL_CHUNK_SIZE >= sizeof(struct regional));
 213         /* debug print */
 214         log_info("regional %u chunks, %u large",
 215                 (unsigned)count_chunks(r), (unsigned)count_large(r));
 216 }
 217
 218 size_t
 219 regional_get_mem(struct regional* r)
 220 {
 221         return r->first_size + (count_chunks(r)-1)*REGIONAL_CHUNK_SIZE
 222                 + r->total_large;
 223 }