1 /* 2 ** 2007 August 14 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** 13 ** This file contains low-level memory allocation drivers for when 14 ** SQLite will use the standard C-library malloc/realloc/free interface 15 ** to obtain the memory it needs. 16 ** 17 ** This file contains implementations of the low-level memory allocation 18 ** routines specified in the sqlite3_mem_methods object. The content of 19 ** this file is only used if SQLITE_SYSTEM_MALLOC is defined. The 20 ** SQLITE_SYSTEM_MALLOC macro is defined automatically if neither the 21 ** SQLITE_MEMDEBUG nor the SQLITE_WIN32_MALLOC macros are defined. The 22 ** default configuration is to use memory allocation routines in this 23 ** file. 24 ** 25 ** C-preprocessor macro summary: 26 ** 27 ** HAVE_MALLOC_USABLE_SIZE The configure script sets this symbol if 28 ** the malloc_usable_size() interface exists 29 ** on the target platform. Or, this symbol 30 ** can be set manually, if desired. 31 ** If an equivalent interface exists by 32 ** a different name, using a separate -D 33 ** option to rename it. 34 ** 35 ** SQLITE_WITHOUT_ZONEMALLOC Some older macs lack support for the zone 36 ** memory allocator. Set this symbol to enable 37 ** building on older macs. 38 ** 39 ** SQLITE_WITHOUT_MSIZE Set this symbol to disable the use of 40 ** _msize() on windows systems. This might 41 ** be necessary when compiling for Delphi, 42 ** for example. 43 */ 44 #include "sqliteInt.h" 45 46 /* 47 ** This version of the memory allocator is the default. It is 48 ** used when no other memory allocator is specified using compile-time 49 ** macros. 50 */ 51 #ifdef SQLITE_SYSTEM_MALLOC 52 #if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC) 53 54 /* 55 ** Use the zone allocator available on apple products unless the 56 ** SQLITE_WITHOUT_ZONEMALLOC symbol is defined. 57 */ 58 #include <sys/sysctl.h> 59 #include <malloc/malloc.h> 60 #include <libkern/OSAtomic.h> 61 static malloc_zone_t* _sqliteZone_; 62 #define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x)) 63 #define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x)); 64 #define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y)) 65 #define SQLITE_MALLOCSIZE(x) \ 66 (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x)) 67 68 #else /* if not __APPLE__ */ 69 70 /* 71 ** Use standard C library malloc and free on non-Apple systems. 72 ** Also used by Apple systems if SQLITE_WITHOUT_ZONEMALLOC is defined. 73 */ 74 #define SQLITE_MALLOC(x) malloc(x) 75 #define SQLITE_FREE(x) free(x) 76 #define SQLITE_REALLOC(x,y) realloc((x),(y)) 77 78 /* 79 ** The malloc.h header file is needed for malloc_usable_size() function 80 ** on some systems (e.g. Linux). 81 */ 82 #if HAVE_MALLOC_H && HAVE_MALLOC_USABLE_SIZE 83 # define SQLITE_USE_MALLOC_H 1 84 # define SQLITE_USE_MALLOC_USABLE_SIZE 1 85 /* 86 ** The MSVCRT has malloc_usable_size(), but it is called _msize(). The 87 ** use of _msize() is automatic, but can be disabled by compiling with 88 ** -DSQLITE_WITHOUT_MSIZE. Using the _msize() function also requires 89 ** the malloc.h header file. 90 */ 91 #elif defined(_MSC_VER) && !defined(SQLITE_WITHOUT_MSIZE) 92 # define SQLITE_USE_MALLOC_H 93 # define SQLITE_USE_MSIZE 94 #endif 95 96 /* 97 ** Include the malloc.h header file, if necessary. Also set define macro 98 ** SQLITE_MALLOCSIZE to the appropriate function name, which is _msize() 99 ** for MSVC and malloc_usable_size() for most other systems (e.g. Linux). 100 ** The memory size function can always be overridden manually by defining 101 ** the macro SQLITE_MALLOCSIZE to the desired function name. 102 */ 103 #if defined(SQLITE_USE_MALLOC_H) 104 # include <malloc.h> 105 # if defined(SQLITE_USE_MALLOC_USABLE_SIZE) 106 # if !defined(SQLITE_MALLOCSIZE) 107 # define SQLITE_MALLOCSIZE(x) malloc_usable_size(x) 108 # endif 109 # elif defined(SQLITE_USE_MSIZE) 110 # if !defined(SQLITE_MALLOCSIZE) 111 # define SQLITE_MALLOCSIZE _msize 112 # endif 113 # endif 114 #endif /* defined(SQLITE_USE_MALLOC_H) */ 115 116 #endif /* __APPLE__ or not __APPLE__ */ 117 118 /* 119 ** Like malloc(), but remember the size of the allocation 120 ** so that we can find it later using sqlite3MemSize(). 121 ** 122 ** For this low-level routine, we are guaranteed that nByte>0 because 123 ** cases of nByte<=0 will be intercepted and dealt with by higher level 124 ** routines. 125 */ 126 static void *sqlite3MemMalloc(int nByte){ 127 #ifdef SQLITE_MALLOCSIZE 128 void *p = SQLITE_MALLOC( nByte ); 129 if( p==0 ){ 130 testcase( sqlite3GlobalConfig.xLog!=0 ); 131 sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte); 132 } 133 return p; 134 #else 135 sqlite3_int64 *p; 136 assert( nByte>0 ); 137 nByte = ROUND8(nByte); 138 p = SQLITE_MALLOC( nByte+8 ); 139 if( p ){ 140 p[0] = nByte; 141 p++; 142 }else{ 143 testcase( sqlite3GlobalConfig.xLog!=0 ); 144 sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte); 145 } 146 return (void *)p; 147 #endif 148 } 149 150 /* 151 ** Like free() but works for allocations obtained from sqlite3MemMalloc() 152 ** or sqlite3MemRealloc(). 153 ** 154 ** For this low-level routine, we already know that pPrior!=0 since 155 ** cases where pPrior==0 will have been intecepted and dealt with 156 ** by higher-level routines. 157 */ 158 static void sqlite3MemFree(void *pPrior){ 159 #ifdef SQLITE_MALLOCSIZE 160 SQLITE_FREE(pPrior); 161 #else 162 sqlite3_int64 *p = (sqlite3_int64*)pPrior; 163 assert( pPrior!=0 ); 164 p--; 165 SQLITE_FREE(p); 166 #endif 167 } 168 169 /* 170 ** Report the allocated size of a prior return from xMalloc() 171 ** or xRealloc(). 172 */ 173 static int sqlite3MemSize(void *pPrior){ 174 #ifdef SQLITE_MALLOCSIZE 175 assert( pPrior!=0 ); 176 return (int)SQLITE_MALLOCSIZE(pPrior); 177 #else 178 sqlite3_int64 *p; 179 assert( pPrior!=0 ); 180 p = (sqlite3_int64*)pPrior; 181 p--; 182 return (int)p[0]; 183 #endif 184 } 185 186 /* 187 ** Like realloc(). Resize an allocation previously obtained from 188 ** sqlite3MemMalloc(). 189 ** 190 ** For this low-level interface, we know that pPrior!=0. Cases where 191 ** pPrior==0 while have been intercepted by higher-level routine and 192 ** redirected to xMalloc. Similarly, we know that nByte>0 because 193 ** cases where nByte<=0 will have been intercepted by higher-level 194 ** routines and redirected to xFree. 195 */ 196 static void *sqlite3MemRealloc(void *pPrior, int nByte){ 197 #ifdef SQLITE_MALLOCSIZE 198 void *p = SQLITE_REALLOC(pPrior, nByte); 199 if( p==0 ){ 200 testcase( sqlite3GlobalConfig.xLog!=0 ); 201 sqlite3_log(SQLITE_NOMEM, 202 "failed memory resize %u to %u bytes", 203 SQLITE_MALLOCSIZE(pPrior), nByte); 204 } 205 return p; 206 #else 207 sqlite3_int64 *p = (sqlite3_int64*)pPrior; 208 assert( pPrior!=0 && nByte>0 ); 209 assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */ 210 p--; 211 p = SQLITE_REALLOC(p, nByte+8 ); 212 if( p ){ 213 p[0] = nByte; 214 p++; 215 }else{ 216 testcase( sqlite3GlobalConfig.xLog!=0 ); 217 sqlite3_log(SQLITE_NOMEM, 218 "failed memory resize %u to %u bytes", 219 sqlite3MemSize(pPrior), nByte); 220 } 221 return (void*)p; 222 #endif 223 } 224 225 /* 226 ** Round up a request size to the next valid allocation size. 227 */ 228 static int sqlite3MemRoundup(int n){ 229 return ROUND8(n); 230 } 231 232 /* 233 ** Initialize this module. 234 */ 235 static int sqlite3MemInit(void *NotUsed){ 236 #if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC) 237 int cpuCount; 238 size_t len; 239 if( _sqliteZone_ ){ 240 return SQLITE_OK; 241 } 242 len = sizeof(cpuCount); 243 /* One usually wants to use hw.acctivecpu for MT decisions, but not here */ 244 sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0); 245 if( cpuCount>1 ){ 246 /* defer MT decisions to system malloc */ 247 _sqliteZone_ = malloc_default_zone(); 248 }else{ 249 /* only 1 core, use our own zone to contention over global locks, 250 ** e.g. we have our own dedicated locks */ 251 bool success; 252 malloc_zone_t* newzone = malloc_create_zone(4096, 0); 253 malloc_set_zone_name(newzone, "Sqlite_Heap"); 254 do{ 255 success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, 256 (void * volatile *)&_sqliteZone_); 257 }while(!_sqliteZone_); 258 if( !success ){ 259 /* somebody registered a zone first */ 260 malloc_destroy_zone(newzone); 261 } 262 } 263 #endif 264 UNUSED_PARAMETER(NotUsed); 265 return SQLITE_OK; 266 } 267 268 /* 269 ** Deinitialize this module. 270 */ 271 static void sqlite3MemShutdown(void *NotUsed){ 272 UNUSED_PARAMETER(NotUsed); 273 return; 274 } 275 276 /* 277 ** This routine is the only routine in this file with external linkage. 278 ** 279 ** Populate the low-level memory allocation function pointers in 280 ** sqlite3GlobalConfig.m with pointers to the routines in this file. 281 */ 282 void sqlite3MemSetDefault(void){ 283 static const sqlite3_mem_methods defaultMethods = { 284 sqlite3MemMalloc, 285 sqlite3MemFree, 286 sqlite3MemRealloc, 287 sqlite3MemSize, 288 sqlite3MemRoundup, 289 sqlite3MemInit, 290 sqlite3MemShutdown, 291 0 292 }; 293 sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods); 294 } 295 296 #endif /* SQLITE_SYSTEM_MALLOC */ 297