/ Check-in [40b598c8]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Add experimental feature to detect threading bugs in apps that use SQLITE_CONFIG_MULTITHREADED. Enabled at compile time using SQLITE_ENABLE_MULTITHREADED_CHECKS.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256:40b598c8392f030f6ed8c63ce81cb0426bb3984397c19c756215f6a569a40164
User & Date: dan 2017-11-28 07:52:00
Context
2017-11-28
13:39
Lock the wal file for all snapshot transactions, even if they would not otherwise require this, preventing checkpointers and writers from wrapping the wal file. This means that if one connection has an open snapshot transaction it is guaranteed that a second connection can open a transaction on the same snapshot. check-in: b81a3149 user: dan tags: trunk
08:08
Merge latest trunk changes, including the SQLITE_ENABLE_MULTITHREADED_CHECKS feature, into this branch. check-in: 1fd10349 user: dan tags: apple-osx
07:52
Add experimental feature to detect threading bugs in apps that use SQLITE_CONFIG_MULTITHREADED. Enabled at compile time using SQLITE_ENABLE_MULTITHREADED_CHECKS. check-in: 40b598c8 user: dan tags: trunk
07:47
Use a symbolic constant instead of a literal (-1) to identify a warn-on-contention mutex. Closed-Leaf check-in: 12a23c0a user: dan tags: multithreaded-checks
00:52
Update tests to deal with SQLITE_FAST_SECURE_DELETE. check-in: e6b89304 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/main.c.

2818
2819
2820
2821
2822
2823
2824

2825
2826
2827
2828
2829
2830
2831
....
2850
2851
2852
2853
2854
2855
2856
2857




2858
2859
2860
2861
2862
2863



2864
2865
2866
2867
2868
2869
2870
  }else if( flags & SQLITE_OPEN_NOMUTEX ){
    isThreadsafe = 0;
  }else if( flags & SQLITE_OPEN_FULLMUTEX ){
    isThreadsafe = 1;
  }else{
    isThreadsafe = sqlite3GlobalConfig.bFullMutex;
  }

  if( flags & SQLITE_OPEN_PRIVATECACHE ){
    flags &= ~SQLITE_OPEN_SHAREDCACHE;
  }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
    flags |= SQLITE_OPEN_SHAREDCACHE;
  }

  /* Remove harmful bits from the flags parameter
................................................................................
               SQLITE_OPEN_FULLMUTEX |
               SQLITE_OPEN_WAL
             );

  /* Allocate the sqlite data structure */
  db = sqlite3MallocZero( sizeof(sqlite3) );
  if( db==0 ) goto opendb_out;
  if( isThreadsafe ){




    db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
    if( db->mutex==0 ){
      sqlite3_free(db);
      db = 0;
      goto opendb_out;
    }



  }
  sqlite3_mutex_enter(db->mutex);
  db->errMask = 0xff;
  db->nDb = 2;
  db->magic = SQLITE_MAGIC_BUSY;
  db->aDb = db->aDbStatic;








>







 







|
>
>
>
>






>
>
>







2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
....
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
  }else if( flags & SQLITE_OPEN_NOMUTEX ){
    isThreadsafe = 0;
  }else if( flags & SQLITE_OPEN_FULLMUTEX ){
    isThreadsafe = 1;
  }else{
    isThreadsafe = sqlite3GlobalConfig.bFullMutex;
  }

  if( flags & SQLITE_OPEN_PRIVATECACHE ){
    flags &= ~SQLITE_OPEN_SHAREDCACHE;
  }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
    flags |= SQLITE_OPEN_SHAREDCACHE;
  }

  /* Remove harmful bits from the flags parameter
................................................................................
               SQLITE_OPEN_FULLMUTEX |
               SQLITE_OPEN_WAL
             );

  /* Allocate the sqlite data structure */
  db = sqlite3MallocZero( sizeof(sqlite3) );
  if( db==0 ) goto opendb_out;
  if( isThreadsafe 
#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
   || sqlite3GlobalConfig.bCoreMutex
#endif
  ){
    db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
    if( db->mutex==0 ){
      sqlite3_free(db);
      db = 0;
      goto opendb_out;
    }
    if( isThreadsafe==0 ){
      sqlite3MutexWarnOnContention(db->mutex);
    }
  }
  sqlite3_mutex_enter(db->mutex);
  db->errMask = 0xff;
  db->nDb = 2;
  db->magic = SQLITE_MAGIC_BUSY;
  db->aDb = db->aDbStatic;

Changes to src/mutex.c.

22
23
24
25
26
27
28



























































































































































































29
30
31
32
33
34
35
..
37
38
39
40
41
42
43



44

45
46
47
48
49
50
51
...
163
164
165
166
167
168
169

** allocate a mutex while the system is uninitialized.
*/
static SQLITE_WSD int mutexIsInit = 0;
#endif /* SQLITE_DEBUG && !defined(SQLITE_MUTEX_OMIT) */


#ifndef SQLITE_MUTEX_OMIT



























































































































































































/*
** 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
................................................................................
    ** sqlite3_initialize() being called. This block copies pointers to
    ** 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;
................................................................................
int sqlite3_mutex_notheld(sqlite3_mutex *p){
  assert( p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld );
  return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p);
}
#endif

#endif /* !defined(SQLITE_MUTEX_OMIT) */








>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







>
>
>

>







 







>
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
...
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
...
354
355
356
357
358
359
360
361
** allocate a mutex while the system is uninitialized.
*/
static SQLITE_WSD int mutexIsInit = 0;
#endif /* SQLITE_DEBUG && !defined(SQLITE_MUTEX_OMIT) */


#ifndef SQLITE_MUTEX_OMIT

#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
/*
** This block (enclosed by SQLITE_ENABLE_MULTITHREADED_CHECKS) contains
** the implementation of a wrapper around the system default mutex
** implementation (sqlite3DefaultMutex()). 
**
** Most calls are passed directly through to the underlying default
** mutex implementation. Except, if a mutex is configured by calling
** sqlite3MutexWarnOnContention() on it, then if contention is ever
** encountered within xMutexEnter() a warning is emitted via sqlite3_log().
**
** This type of mutex is used as the database handle mutex when testing
** apps that usually use SQLITE_CONFIG_MULTITHREAD mode.
*/

/* 
** Type for all mutexes used when SQLITE_ENABLE_MULTITHREADED_CHECKS
** is defined. Variable CheckMutex.mutex is a pointer to the real mutex
** allocated by the system mutex implementation. Variable iType is usually set
** to the type of mutex requested - SQLITE_MUTEX_RECURSIVE, SQLITE_MUTEX_FAST
** or one of the static mutex identifiers. Or, if this is a recursive mutex
** that has been configured using sqlite3MutexWarnOnContention(), it is
** set to SQLITE_MUTEX_WARNONCONTENTION.
*/
typedef struct CheckMutex CheckMutex;
struct CheckMutex {
  int iType;
  sqlite3_mutex *mutex;
};

#define SQLITE_MUTEX_WARNONCONTENTION  (-1)

/* 
** Pointer to real mutex methods object used by the CheckMutex
** implementation. Set by checkMutexInit(). 
*/
static SQLITE_WSD const sqlite3_mutex_methods *pGlobalMutexMethods;

#ifdef SQLITE_DEBUG
static int checkMutexHeld(sqlite3_mutex *p){
  return pGlobalMutexMethods->xMutexHeld(((CheckMutex*)p)->mutex);
}
static int checkMutexNotheld(sqlite3_mutex *p){
  return pGlobalMutexMethods->xMutexNotheld(((CheckMutex*)p)->mutex);
}
#endif

/*
** Initialize and deinitialize the mutex subsystem.
*/
static int checkMutexInit(void){ 
  pGlobalMutexMethods = sqlite3DefaultMutex();
  return SQLITE_OK; 
}
static int checkMutexEnd(void){ 
  pGlobalMutexMethods = 0;
  return SQLITE_OK; 
}

/*
** Allocate a mutex.
*/
static sqlite3_mutex *checkMutexAlloc(int iType){
  static CheckMutex staticMutexes[] = {
    {2, 0}, {3, 0}, {4, 0}, {5, 0},
    {6, 0}, {7, 0}, {8, 0}, {9, 0},
    {10, 0}, {11, 0}, {12, 0}, {13, 0}
  };
  CheckMutex *p = 0;

  assert( SQLITE_MUTEX_RECURSIVE==1 && SQLITE_MUTEX_FAST==0 );
  if( iType<2 ){
    p = sqlite3MallocZero(sizeof(CheckMutex));
    if( p==0 ) return 0;
    p->iType = iType;
  }else{
#ifdef SQLITE_ENABLE_API_ARMOR
    if( iType-2>=ArraySize(staticMutexes) ){
      (void)SQLITE_MISUSE_BKPT;
      return 0;
    }
#endif
    p = &staticMutexes[iType-2];
  }

  if( p->mutex==0 ){
    p->mutex = pGlobalMutexMethods->xMutexAlloc(iType);
    if( p->mutex==0 ){
      if( iType<2 ){
        sqlite3_free(p);
      }
      p = 0;
    }
  }

  return (sqlite3_mutex*)p;
}

/*
** Free a mutex.
*/
static void checkMutexFree(sqlite3_mutex *p){
  assert( SQLITE_MUTEX_RECURSIVE<2 );
  assert( SQLITE_MUTEX_FAST<2 );
  assert( SQLITE_MUTEX_WARNONCONTENTION<2 );

#if SQLITE_ENABLE_API_ARMOR
  if( p->iType<2 ){
#endif
  {
    CheckMutex *pCheck = (CheckMutex*)p;
    pGlobalMutexMethods->xMutexFree(pCheck->mutex);
    sqlite3_free(pCheck);
  }
#ifdef SQLITE_ENABLE_API_ARMOR
  else{
    (void)SQLITE_MISUSE_BKPT;
  }
#endif
}

/*
** Enter the mutex.
*/
static void checkMutexEnter(sqlite3_mutex *p){
  CheckMutex *pCheck = (CheckMutex*)p;
  if( pCheck->iType==SQLITE_MUTEX_WARNONCONTENTION ){
    if( SQLITE_OK==pGlobalMutexMethods->xMutexTry(pCheck->mutex) ){
      return;
    }
    sqlite3_log(SQLITE_MISUSE, 
        "illegal multi-threaded access to database connection"
    );
  }
  pGlobalMutexMethods->xMutexEnter(pCheck->mutex);
}

/*
** Enter the mutex (do not block).
*/
static int checkMutexTry(sqlite3_mutex *p){
  CheckMutex *pCheck = (CheckMutex*)p;
  return pGlobalMutexMethods->xMutexTry(pCheck->mutex);
}

/*
** Leave the mutex.
*/
static void checkMutexLeave(sqlite3_mutex *p){
  CheckMutex *pCheck = (CheckMutex*)p;
  pGlobalMutexMethods->xMutexLeave(pCheck->mutex);
}

sqlite3_mutex_methods const *multiThreadedCheckMutex(void){
  static const sqlite3_mutex_methods sMutex = {
    checkMutexInit,
    checkMutexEnd,
    checkMutexAlloc,
    checkMutexFree,
    checkMutexEnter,
    checkMutexTry,
    checkMutexLeave,
#ifdef SQLITE_DEBUG
    checkMutexHeld,
    checkMutexNotheld
#else
    0,
    0
#endif
  };
  return &sMutex;
}

/*
** Mark the SQLITE_MUTEX_RECURSIVE mutex passed as the only argument as
** one on which there should be no contention.
*/
void sqlite3MutexWarnOnContention(sqlite3_mutex *p){
  if( sqlite3GlobalConfig.mutex.xMutexAlloc==checkMutexAlloc ){
    CheckMutex *pCheck = (CheckMutex*)p;
    assert( pCheck->iType==SQLITE_MUTEX_RECURSIVE );
    pCheck->iType = SQLITE_MUTEX_WARNONCONTENTION;
  }
}
#endif   /* ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS */

/*
** 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
................................................................................
    ** sqlite3_initialize() being called. This block copies pointers to
    ** the default implementation into the sqlite3GlobalConfig structure.
    */
    sqlite3_mutex_methods const *pFrom;
    sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex;

    if( sqlite3GlobalConfig.bCoreMutex ){
#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
      pFrom = multiThreadedCheckMutex();
#else
      pFrom = sqlite3DefaultMutex();
#endif
    }else{
      pFrom = sqlite3NoopMutex();
    }
    pTo->xMutexInit = pFrom->xMutexInit;
    pTo->xMutexEnd = pFrom->xMutexEnd;
    pTo->xMutexFree = pFrom->xMutexFree;
    pTo->xMutexEnter = pFrom->xMutexEnter;
................................................................................
int sqlite3_mutex_notheld(sqlite3_mutex *p){
  assert( p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld );
  return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p);
}
#endif

#endif /* !defined(SQLITE_MUTEX_OMIT) */

Changes to src/sqliteInt.h.

3585
3586
3587
3588
3589
3590
3591






3592
3593
3594
3595
3596
3597
3598
void sqlite3StatusDown(int, int);
void sqlite3StatusHighwater(int, int);
int sqlite3LookasideUsed(sqlite3*,int*);

/* Access to mutexes used by sqlite3_status() */
sqlite3_mutex *sqlite3Pcache1Mutex(void);
sqlite3_mutex *sqlite3MallocMutex(void);







#ifndef SQLITE_OMIT_FLOATING_POINT
  int sqlite3IsNaN(double);
#else
# define sqlite3IsNaN(X)  0
#endif








>
>
>
>
>
>







3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
void sqlite3StatusDown(int, int);
void sqlite3StatusHighwater(int, int);
int sqlite3LookasideUsed(sqlite3*,int*);

/* Access to mutexes used by sqlite3_status() */
sqlite3_mutex *sqlite3Pcache1Mutex(void);
sqlite3_mutex *sqlite3MallocMutex(void);

#if defined(SQLITE_ENABLE_MULTITHREADED_CHECKS) && !defined(SQLITE_MUTEX_OMIT)
void sqlite3MutexWarnOnContention(sqlite3_mutex*);
#else
# define sqlite3MutexWarnOnContention(x)
#endif

#ifndef SQLITE_OMIT_FLOATING_POINT
  int sqlite3IsNaN(double);
#else
# define sqlite3IsNaN(X)  0
#endif