Merge updates from trunk.

FossilOrigin-Name: 6b85f8cd4d87d616a3cb362647ae3869c45c2801

manifest

@@ -1,5 +1,5 @@
-C Capture\sAFL-generated\sfuzz\stests\sfor\sjson1.c\sinto\sthe\stest/fuzzdata4.db\sfile.
-D 2015-09-23T11:59:50.725
+C Merge\supdates\sfrom\strunk.
+D 2015-09-23T15:54:36.389
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in e1afa6fb2de2bddd50e0ddae8166c2ee9d69b301
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -296,7 +296,7 @@ F src/expr.c 3a76afcdac925294c39903b7002ddb9e5fd29863
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 83e1baba999bed3144ea5a2143fc922edf51135f
 F src/func.c ecdd69ec6a1e406f04cc73324be2ebbf6354197f
-F src/global.c 508e4087f7b41d688e4762dcf4d4fe28cfbc87f9
+F src/global.c d824163680839be79b53204105a78e5be5d4ac4a
 F src/hash.c 4263fbc955f26c2e8cdc0cf214bc42435aa4e4f5
 F src/hash.h c8f3c31722cf3277d03713909761e152a5b81094
 F src/hwtime.h d32741c8f4df852c7d959236615444e2b1063b08
@@ -305,7 +305,7 @@ F src/journal.c b4124532212b6952f42eb2c12fa3c25701d8ba8d
 F src/legacy.c ba1863ea58c4c840335a84ec276fc2b25e22bc4e
 F src/lempar.c d344a95d60c24e2f490ee59db9784b1b17439012
 F src/loadext.c f0b66d28e377fd6c6d36cc9d92df1ff251ebee44
-F src/main.c e17fcffae4306a9b8334faf3bac80d7396850b54
+F src/main.c 9f196a4364270af28ab97c1d62046e56e32dd11d
 F src/malloc.c 3a37ce6979a40f499d8cea9e9ab4e8517854d35d
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c abe6ee469b6c5a35c7f22bfeb9c9bac664a1c987
@@ -314,11 +314,11 @@ F src/mem3.c 61c9d47b792908c532ca3a62b999cf21795c6534
 F src/mem5.c 61eeb90134f9a5be6c2e68d8daae7628b25953fb
 F src/memjournal.c 3eb2c0b51adbd869cb6a44780323f05fa904dc85
 F src/msvc.h d9ba56c6851227ab44b3f228a35f3f5772296495
-F src/mutex.c 8e45800ee78e0cd1f1f3fe8e398853307f4a085c
+F src/mutex.c b0fbea2cda9f8e81444f5f1b4b9f07c1a904269e
 F src/mutex.h 779d588e3b7756ec3ecf7d78cde1d84aba414f85
-F src/mutex_noop.c 9d4309c075ba9cc7249e19412d3d62f7f94839c4
-F src/mutex_unix.c 8cfa6e83c618d2fcae0fe63f4d2b5bb16b11a97a
-F src/mutex_w32.c 2e025e6642eaf27597403690980f560d1a91f62c
+F src/mutex_noop.c f03e26ba8258399da23b51234f6b6a97197c1900
+F src/mutex_unix.c a72043f2560147d8e85fe48a6aef682896deb3a0
+F src/mutex_w32.c 928c889408e3196f325d23fa4d115b3bc59d8eb6
 F src/notify.c 9711a7575036f0d3040ba61bc6e217f13a9888e7
 F src/os.c 8fd25588eeba74068d41102d26810e216999b6c8
 F src/os.h 3e57a24e2794a94d3cf2342c6d9a884888cd96bf
@@ -345,7 +345,7 @@ F src/shell.c 6332ef06db1390ef812cfdff1fc97b4fd76cdd42
 F src/sqlite.h.in 4e06cb5fed36736242c66237991db6f3e2395eb9
 F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
 F src/sqlite3ext.h 64350bf36833a56ad675e27392a913f417c5c308
-F src/sqliteInt.h 5afc6e50402be1e0a870f28e1cd8b32eb9db590f
+F src/sqliteInt.h ed65bcb0a6a7c11978c8f75d5476d6edaa024e8d
 F src/sqliteLimit.h 216557999cb45f2e3578ed53ebefe228d779cb46
 F src/status.c f266ad8a2892d659b74f0f50cb6a88b6e7c12179
 F src/table.c 51b46b2a62d1b3a959633d593b89bab5e2c9155e
@@ -1388,7 +1388,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 7c7a3f3e9bc2f7a7334d8d6eae183d83f22097be
-R 64646de8f025fcbfbac14050e58f6d8a
-U drh
-Z 8d3625ca1ecc6df3eff60cf48fea0eb8
+P c9400ff167d9520119081c9b92436794dcd53d22 10a214fdb3c13b25e0bdd15c975c21c8890c47ee
+R b42897c3c8ae6a403b71a2f426cb59b5
+U mistachkin
+Z 6c86ab7133863d50d8bbe949c96c8dea

manifest.uuid

@@ -1 +1 @@
-10a214fdb3c13b25e0bdd15c975c21c8890c47ee
+6b85f8cd4d87d616a3cb362647ae3869c45c2801

src/global.c

@@ -174,6 +174,7 @@ SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    128,                       /* szLookaside */
    500,                       /* nLookaside */
    {0,0,0,0,0,0,0,0},         /* m */
+   (void*)0,                  /* pMutex */
    {0,0,0,0,0,0,0,0,0},       /* mutex */
    {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */
    (void*)0,                  /* pHeap */

src/main.c

@@ -171,7 +171,13 @@ int sqlite3_initialize(void){
   */
   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
   sqlite3_mutex_enter(pMaster);
-  sqlite3GlobalConfig.isMutexInit = 1;
+  if( sqlite3GlobalConfig.isInit ){
+    assert( sqlite3GlobalConfig.isMutexInit );
+    assert( sqlite3GlobalConfig.isMallocInit );
+    sqlite3_mutex_leave(pMaster);
+    return SQLITE_OK;
+  }
+  sqlite3GlobalConfig.isMutexInit = 1; /* possibly redundant */
   if( !sqlite3GlobalConfig.isMallocInit ){
     rc = sqlite3MallocInit();
   }
@@ -329,6 +335,17 @@ int sqlite3_shutdown(void){
     sqlite3GlobalConfig.isMutexInit = 0;
   }
 
+  /*
+  ** Force the state of the mutex subsystem to be completely reset now, even
+  ** if the configured xMutexEnd(), if any, failed.  This is not thread-safe.
+  ** This is necessary even if the xMutexInit() was never called, due to the
+  ** possiblity of this state being changed via SQLITE_CONFIG_MUTEX.  After
+  ** this point, the application must enable any custom mutex implementation
+  ** again via SQLITE_CONFIG_MUTEX, if necessary.
+  */
+  sqlite3GlobalConfig.pMutex = 0;
+  memset(&sqlite3GlobalConfig.mutex, 0, sizeof(sqlite3_mutex_methods));
+
   return SQLITE_OK;
 }
 
@@ -384,8 +401,15 @@ int sqlite3_config(int op, ...){
 #endif
 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
     case SQLITE_CONFIG_MUTEX: {
-      /* Specify an alternative mutex implementation */
-      sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
+      /* Atomically compare-and-swap the mutex implementation pointer to
+       * help prevent a race condition with sqlite3MutexInit(). */
+      if( sqlite3CompareAndSwap((void * volatile *)&sqlite3GlobalConfig.pMutex,
+                                0, &sqlite3GlobalConfig.mutex)==0 ){
+        /* Specify an alternative mutex implementation */
+        sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
+      }else{
+        rc = SQLITE_ERROR;
+      }
       break;
     }
 #endif

src/mutex.c

@@ -26,38 +26,80 @@ static SQLITE_WSD int mutexIsInit = 0;
 
 
 #ifndef SQLITE_MUTEX_OMIT
+/*
+** This structure is for use by mutexIsInvalid() only.  It represents an
+** invalid mutex implementation (i.e. one where all the function pointers
+** are null).
+*/
+static const sqlite3_mutex_methods mutexNullMethods = {
+  0, /* xMutexInit */
+  0, /* xMutexEnd */
+  0, /* xMutexAlloc */
+  0, /* xMutexFree */
+  0, /* xMutexEnter */
+  0, /* xMutexTry */
+  0, /* xMutexLeave */
+  0, /* xMutexHeld */
+  0  /* xMutexNotheld */
+};
+
+/*
+** Returns non-zero if the currently configured mutex implemention is
+** invalid (i.e. all of its function pointers are null).
+*/
+static int mutexIsInvalid(void){
+  return memcmp(&sqlite3GlobalConfig.mutex, &mutexNullMethods,
+                sizeof(sqlite3_mutex_methods))==0;
+}
+
+/*
+** Copies a mutex implementation.  Both arguments must point to valid
+** memory.
+*/
+static void mutexCopy(
+  sqlite3_mutex_methods *pTo,
+  sqlite3_mutex_methods const *pFrom
+){
+  pTo->xMutexInit = pFrom->xMutexInit;
+  pTo->xMutexEnd = pFrom->xMutexEnd;
+  pTo->xMutexFree = pFrom->xMutexFree;
+  pTo->xMutexEnter = pFrom->xMutexEnter;
+  pTo->xMutexTry = pFrom->xMutexTry;
+  pTo->xMutexLeave = pFrom->xMutexLeave;
+  pTo->xMutexHeld = pFrom->xMutexHeld;
+  pTo->xMutexNotheld = pFrom->xMutexNotheld;
+  pTo->xMutexAlloc = pFrom->xMutexAlloc;
+}
+
 /*
 ** Initialize the mutex system.
 */
 int sqlite3MutexInit(void){ 
-  int rc = SQLITE_OK;
-  if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){
-    /* If the xMutexAlloc method has not been set, then the user did not
-    ** install a mutex implementation via sqlite3_config() prior to 
-    ** sqlite3_initialize() being called. This block copies pointers to
-    ** the default implementation into the sqlite3GlobalConfig structure.
+  static int initPending = 0;
+  int rc;
+  if( sqlite3CompareAndSwap((void * volatile *)&sqlite3GlobalConfig.pMutex,
+                   0, &sqlite3GlobalConfig.mutex)==0 || mutexIsInvalid() ){
+    /* If the mutex implementation pointer has not been set, then the user
+    ** did not install a mutex implementation via sqlite3_config() prior to
+    ** sqlite3_initialize() being called.  This block copies the pointers
+    ** for the default implementation into the sqlite3GlobalConfig structure.
     */
     sqlite3_mutex_methods const *pFrom;
-    sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex;
 
     if( sqlite3GlobalConfig.bCoreMutex ){
       pFrom = sqlite3DefaultMutex();
     }else{
       pFrom = sqlite3NoopMutex();
     }
-    pTo->xMutexInit = pFrom->xMutexInit;
-    pTo->xMutexEnd = pFrom->xMutexEnd;
-    pTo->xMutexFree = pFrom->xMutexFree;
-    pTo->xMutexEnter = pFrom->xMutexEnter;
-    pTo->xMutexTry = pFrom->xMutexTry;
-    pTo->xMutexLeave = pFrom->xMutexLeave;
-    pTo->xMutexHeld = pFrom->xMutexHeld;
-    pTo->xMutexNotheld = pFrom->xMutexNotheld;
+    mutexCopy(&sqlite3GlobalConfig.mutex, pFrom);
     sqlite3MemoryBarrier();
-    pTo->xMutexAlloc = pFrom->xMutexAlloc;
   }
-  assert( sqlite3GlobalConfig.mutex.xMutexInit );
-  rc = sqlite3GlobalConfig.mutex.xMutexInit();
+  if( !initPending ){
+    assert( sqlite3GlobalConfig.mutex.xMutexInit );
+    initPending = 1;
+    rc = sqlite3GlobalConfig.mutex.xMutexInit();
+    initPending = 0;
+  }
 
 #ifdef SQLITE_DEBUG
   GLOBAL(int, mutexIsInit) = 1;

src/mutex_noop.c

@@ -29,6 +29,28 @@
 
 #ifndef SQLITE_MUTEX_OMIT
 
+/*
+** Try to provide an atomic compare-and-swap operation on a void pointer,
+** needed for initialization only.
+*/
+void *sqlite3NoopCompareAndSwap(
+  void *volatile *pCurVal,
+  void *cmpVal,
+  void *swapVal
+){
+  /*
+  ** This platform may not have a way to perform an atomic compare-and-swap
+  ** operation; therefore, use the fallback algorithm.
+  **
+  ** WARNING: This code is almost certainly not thread-safe.
+  */
+  void *oldVal = *pCurVal;
+  if( oldVal==cmpVal ){
+    *pCurVal = swapVal;
+  }
+  return oldVal;
+}
+
 #ifndef SQLITE_DEBUG
 /*
 ** Stub routines for all mutex methods.

src/mutex_unix.c

@@ -91,6 +91,34 @@ void sqlite3MemoryBarrier(void){
 #endif
 }
 
+/*
+** Try to provide an atomic compare-and-swap operation on a void pointer,
+** needed for initialization only.
+*/
+void *sqlite3CompareAndSwap(
+  void *volatile *pCurVal,
+  void *cmpVal,
+  void *swapVal
+){
+#if defined(SQLITE_COMPARE_AND_SWAP)
+  return SQLITE_COMPARE_AND_SWAP(pCurVal, cmpVal, swapVal);
+#elif defined(__GNUC__) && GCC_VERSION>=4001000 && SQLITE_PTRSIZE>4
+  return (void *)__sync_val_compare_and_swap_8(
+      (u64 volatile *)pCurVal, (u64)cmpVal, (u64)swapVal);
+#elif defined(__GNUC__) && GCC_VERSION>=4001000
+  return (void *)__sync_val_compare_and_swap_4(
+      (u32 volatile *)pCurVal, (u32)cmpVal, (u32)swapVal);
+#else
+  /*
+  ** This platform may not have a way to perform an atomic compare-and-swap
+  ** operation; therefore, use the fallback algorithm.
+  **
+  ** WARNING: This code is almost certainly not thread-safe.
+  */
+  return sqlite3NoopCompareAndSwap(pCurVal, cmpVal, swapVal);
+#endif
+}
+
 /*
 ** Initialize and deinitialize the mutex subsystem.
 */

src/mutex_w32.c

@@ -90,6 +90,28 @@ void sqlite3MemoryBarrier(void){
 #endif
 }
 
+/*
+** Try to provide an atomic compare-and-swap operation on a void pointer,
+** needed for initialization only.
+*/
+void *sqlite3CompareAndSwap(
+  void * volatile *pCurVal,
+  void *cmpVal,
+  void *swapVal
+){
+#if defined(SQLITE_COMPARE_AND_SWAP)
+  return SQLITE_COMPARE_AND_SWAP(pCurVal, cmpVal, swapVal);
+#elif SQLITE_PTRSIZE>4
+  return (void *)InterlockedCompareExchange64(
+      (LONGLONG SQLITE_WIN32_VOLATILE *)pCurVal, (LONGLONG)swapVal,
+      (LONGLONG)cmpVal);
+#else
+  return (void *)InterlockedCompareExchange(
+      (LONG SQLITE_WIN32_VOLATILE *)pCurVal, (LONG)swapVal,
+      (LONG)cmpVal);
+#endif
+}
+
 /*
 ** Initialize and deinitialize the mutex subsystem.
 */

src/sqliteInt.h

@@ -2938,6 +2938,7 @@ struct Sqlite3Config {
   int szLookaside;                  /* Default lookaside buffer size */
   int nLookaside;                   /* Default lookaside buffer count */
   sqlite3_mem_methods m;            /* Low-level memory allocation interface */
+  sqlite3_mutex_methods *pMutex;    /* Address of mutex member or zero. */
   sqlite3_mutex_methods mutex;      /* Low-level mutex interface */
   sqlite3_pcache_methods2 pcache2;  /* Low-level page-cache interface */
   void *pHeap;                      /* Heap storage space */
@@ -3189,6 +3190,7 @@ const sqlite3_mem_methods *sqlite3MemGetMemsys5(void);
 #ifndef SQLITE_MUTEX_OMIT
   sqlite3_mutex_methods const *sqlite3DefaultMutex(void);
   sqlite3_mutex_methods const *sqlite3NoopMutex(void);
+  void *sqlite3NoopCompareAndSwap(void * volatile *, void *, void *);
   sqlite3_mutex *sqlite3MutexAlloc(int);
   int sqlite3MutexInit(void);
   int sqlite3MutexEnd(void);
@@ -3198,6 +3200,15 @@ const sqlite3_mem_methods *sqlite3MemGetMemsys5(void);
 #else
 # define sqlite3MemoryBarrier()
 #endif
+#if !defined(SQLITE_MUTEX_OMIT)
+# if !defined(SQLITE_MUTEX_NOOP)
+   void *sqlite3CompareAndSwap(void * volatile *, void *, void *);
+# else
+#  define sqlite3CompareAndSwap sqlite3NoopCompareAndSwap
+# endif
+#else
+# define sqlite3CompareAndSwap(x,y,z)
+#endif
 
 sqlite3_int64 sqlite3StatusValue(int);
 void sqlite3StatusUp(int, int);