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. This symbol will 34 ** be enabled automatically on windows 35 ** systems, and malloc_usable_size() will 36 ** be redefined to _msize(), unless the 37 ** SQLITE_WITHOUT_MSIZE macro is defined. 38 ** 39 ** SQLITE_WITHOUT_ZONEMALLOC Some older macs lack support for the zone 40 ** memory allocator. Set this symbol to enable 41 ** building on older macs. 42 ** 43 ** SQLITE_WITHOUT_MSIZE Set this symbol to disable the use of 44 ** _msize() on windows systems. This might 45 ** be necessary when compiling for Delphi, 46 ** for example. 47 */ 48 #include "sqliteInt.h" 49 50 /* 51 ** This version of the memory allocator is the default. It is 52 ** used when no other memory allocator is specified using compile-time 53 ** macros. 54 */ 55 #ifdef SQLITE_SYSTEM_MALLOC 56 57 /* 58 ** Windows systems have malloc_usable_size() but it is called _msize(). 59 ** The use of _msize() is automatic, but can be disabled by compiling 60 ** with -DSQLITE_WITHOUT_MSIZE 61 */ 62 #if !defined(HAVE_MALLOC_USABLE_SIZE) && SQLITE_OS_WIN \ 63 && !defined(SQLITE_WITHOUT_MSIZE) 64 # define HAVE_MALLOC_USABLE_SIZE 1 65 # define malloc_usable_size _msize 66 #endif 67 68 #if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC) 69 70 /* 71 ** Use the zone allocator available on apple products unless the 72 ** SQLITE_WITHOUT_ZONEMALLOC symbol is defined. 73 */ 74 #include <sys/sysctl.h> 75 #include <malloc/malloc.h> 76 #include <libkern/OSAtomic.h> 77 static malloc_zone_t* _sqliteZone_; 78 #define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x)) 79 #define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x)); 80 #define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y)) 81 #define SQLITE_MALLOCSIZE(x) \ 82 (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x)) 83 84 #else /* if not __APPLE__ */ 85 86 /* 87 ** Use standard C library malloc and free on non-Apple systems. 88 ** Also used by Apple systems if SQLITE_WITHOUT_ZONEMALLOC is defined. 89 */ 90 #define SQLITE_MALLOC(x) malloc(x) 91 #define SQLITE_FREE(x) free(x) 92 #define SQLITE_REALLOC(x,y) realloc((x),(y)) 93 94 #ifdef HAVE_MALLOC_USABLE_SIZE 95 #include <malloc.h> 96 #define SQLITE_MALLOCSIZE(x) malloc_usable_size(x) 97 #else 98 #undef SQLITE_MALLOCSIZE 99 #endif 100 101 #endif /* __APPLE__ or not __APPLE__ */ 102 103 /* 104 ** Like malloc(), but remember the size of the allocation 105 ** so that we can find it later using sqlite3MemSize(). 106 ** 107 ** For this low-level routine, we are guaranteed that nByte>0 because 108 ** cases of nByte<=0 will be intercepted and dealt with by higher level 109 ** routines. 110 */ 111 static void *sqlite3MemMalloc(int nByte){ 112 #ifdef SQLITE_MALLOCSIZE 113 void *p = SQLITE_MALLOC( nByte ); 114 if( p==0 ){ 115 testcase( sqlite3GlobalConfig.xLog!=0 ); 116 sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte); 117 } 118 return p; 119 #else 120 sqlite3_int64 *p; 121 assert( nByte>0 ); 122 nByte = ROUND8(nByte); 123 p = SQLITE_MALLOC( nByte+8 ); 124 if( p ){ 125 p[0] = nByte; 126 p++; 127 }else{ 128 testcase( sqlite3GlobalConfig.xLog!=0 ); 129 sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte); 130 } 131 return (void *)p; 132 #endif 133 } 134 135 /* 136 ** Like free() but works for allocations obtained from sqlite3MemMalloc() 137 ** or sqlite3MemRealloc(). 138 ** 139 ** For this low-level routine, we already know that pPrior!=0 since 140 ** cases where pPrior==0 will have been intecepted and dealt with 141 ** by higher-level routines. 142 */ 143 static void sqlite3MemFree(void *pPrior){ 144 #ifdef SQLITE_MALLOCSIZE 145 SQLITE_FREE(pPrior); 146 #else 147 sqlite3_int64 *p = (sqlite3_int64*)pPrior; 148 assert( pPrior!=0 ); 149 p--; 150 SQLITE_FREE(p); 151 #endif 152 } 153 154 /* 155 ** Report the allocated size of a prior return from xMalloc() 156 ** or xRealloc(). 157 */ 158 static int sqlite3MemSize(void *pPrior){ 159 #ifdef SQLITE_MALLOCSIZE 160 return pPrior ? (int)SQLITE_MALLOCSIZE(pPrior) : 0; 161 #else 162 sqlite3_int64 *p; 163 if( pPrior==0 ) return 0; 164 p = (sqlite3_int64*)pPrior; 165 p--; 166 return (int)p[0]; 167 #endif 168 } 169 170 /* 171 ** Like realloc(). Resize an allocation previously obtained from 172 ** sqlite3MemMalloc(). 173 ** 174 ** For this low-level interface, we know that pPrior!=0. Cases where 175 ** pPrior==0 while have been intercepted by higher-level routine and 176 ** redirected to xMalloc. Similarly, we know that nByte>0 becauses 177 ** cases where nByte<=0 will have been intercepted by higher-level 178 ** routines and redirected to xFree. 179 */ 180 static void *sqlite3MemRealloc(void *pPrior, int nByte){ 181 #ifdef SQLITE_MALLOCSIZE 182 void *p = SQLITE_REALLOC(pPrior, nByte); 183 if( p==0 ){ 184 testcase( sqlite3GlobalConfig.xLog!=0 ); 185 sqlite3_log(SQLITE_NOMEM, 186 "failed memory resize %u to %u bytes", 187 SQLITE_MALLOCSIZE(pPrior), nByte); 188 } 189 return p; 190 #else 191 sqlite3_int64 *p = (sqlite3_int64*)pPrior; 192 assert( pPrior!=0 && nByte>0 ); 193 assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */ 194 p--; 195 p = SQLITE_REALLOC(p, nByte+8 ); 196 if( p ){ 197 p[0] = nByte; 198 p++; 199 }else{ 200 testcase( sqlite3GlobalConfig.xLog!=0 ); 201 sqlite3_log(SQLITE_NOMEM, 202 "failed memory resize %u to %u bytes", 203 sqlite3MemSize(pPrior), nByte); 204 } 205 return (void*)p; 206 #endif 207 } 208 209 /* 210 ** Round up a request size to the next valid allocation size. 211 */ 212 static int sqlite3MemRoundup(int n){ 213 return ROUND8(n); 214 } 215 216 /* 217 ** Initialize this module. 218 */ 219 static int sqlite3MemInit(void *NotUsed){ 220 #if defined(__APPLE__) && !defined(SQLITE_WITHOUT_ZONEMALLOC) 221 int cpuCount; 222 size_t len; 223 if( _sqliteZone_ ){ 224 return SQLITE_OK; 225 } 226 len = sizeof(cpuCount); 227 /* One usually wants to use hw.acctivecpu for MT decisions, but not here */ 228 sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0); 229 if( cpuCount>1 ){ 230 /* defer MT decisions to system malloc */ 231 _sqliteZone_ = malloc_default_zone(); 232 }else{ 233 /* only 1 core, use our own zone to contention over global locks, 234 ** e.g. we have our own dedicated locks */ 235 bool success; 236 malloc_zone_t* newzone = malloc_create_zone(4096, 0); 237 malloc_set_zone_name(newzone, "Sqlite_Heap"); 238 do{ 239 success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, 240 (void * volatile *)&_sqliteZone_); 241 }while(!_sqliteZone_); 242 if( !success ){ 243 /* somebody registered a zone first */ 244 malloc_destroy_zone(newzone); 245 } 246 } 247 #endif 248 UNUSED_PARAMETER(NotUsed); 249 return SQLITE_OK; 250 } 251 252 /* 253 ** Deinitialize this module. 254 */ 255 static void sqlite3MemShutdown(void *NotUsed){ 256 UNUSED_PARAMETER(NotUsed); 257 return; 258 } 259 260 /* 261 ** This routine is the only routine in this file with external linkage. 262 ** 263 ** Populate the low-level memory allocation function pointers in 264 ** sqlite3GlobalConfig.m with pointers to the routines in this file. 265 */ 266 void sqlite3MemSetDefault(void){ 267 static const sqlite3_mem_methods defaultMethods = { 268 sqlite3MemMalloc, 269 sqlite3MemFree, 270 sqlite3MemRealloc, 271 sqlite3MemSize, 272 sqlite3MemRoundup, 273 sqlite3MemInit, 274 sqlite3MemShutdown, 275 0 276 }; 277 sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods); 278 } 279 280 #endif /* SQLITE_SYSTEM_MALLOC */ 281