xref: /sqlite-3.40.0/src/test_vfs.c (revision 94e95ea4)
1 /*
2 ** 2010 May 05
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 the implementation of the Tcl [testvfs] command,
14 ** used to create SQLite VFS implementations with various properties and
15 ** instrumentation to support testing SQLite.
16 **
17 **   testvfs VFSNAME ?OPTIONS?
18 **
19 ** Available options are:
20 **
21 **   -noshm      BOOLEAN        (True to omit shm methods. Default false)
22 **   -default    BOOLEAN        (True to make the vfs default. Default false)
23 **   -szosfile   INTEGER        (Value for sqlite3_vfs.szOsFile)
24 **   -mxpathname INTEGER        (Value for sqlite3_vfs.mxPathname)
25 **   -iversion   INTEGER        (Value for sqlite3_vfs.iVersion)
26 */
27 #if SQLITE_TEST          /* This file is used for testing only */
28 
29 #include "sqlite3.h"
30 #include "sqliteInt.h"
31 #if defined(INCLUDE_SQLITE_TCL_H)
32 #  include "sqlite_tcl.h"
33 #else
34 #  include "tcl.h"
35 #endif
36 
37 typedef struct Testvfs Testvfs;
38 typedef struct TestvfsShm TestvfsShm;
39 typedef struct TestvfsBuffer TestvfsBuffer;
40 typedef struct TestvfsFile TestvfsFile;
41 typedef struct TestvfsFd TestvfsFd;
42 
43 /*
44 ** An open file handle.
45 */
46 struct TestvfsFile {
47   sqlite3_file base;              /* Base class.  Must be first */
48   TestvfsFd *pFd;                 /* File data */
49 };
50 #define tvfsGetFd(pFile) (((TestvfsFile *)pFile)->pFd)
51 
52 struct TestvfsFd {
53   sqlite3_vfs *pVfs;              /* The VFS */
54   const char *zFilename;          /* Filename as passed to xOpen() */
55   sqlite3_file *pReal;            /* The real, underlying file descriptor */
56   Tcl_Obj *pShmId;                /* Shared memory id for Tcl callbacks */
57 
58   TestvfsBuffer *pShm;            /* Shared memory buffer */
59   u32 excllock;                   /* Mask of exclusive locks */
60   u32 sharedlock;                 /* Mask of shared locks */
61   TestvfsFd *pNext;               /* Next handle opened on the same file */
62 };
63 
64 
65 #define FAULT_INJECT_NONE       0
66 #define FAULT_INJECT_TRANSIENT  1
67 #define FAULT_INJECT_PERSISTENT 2
68 
69 typedef struct TestFaultInject TestFaultInject;
70 struct TestFaultInject {
71   int iCnt;                       /* Remaining calls before fault injection */
72   int eFault;                     /* A FAULT_INJECT_* value */
73   int nFail;                      /* Number of faults injected */
74 };
75 
76 /*
77 ** An instance of this structure is allocated for each VFS created. The
78 ** sqlite3_vfs.pAppData field of the VFS structure registered with SQLite
79 ** is set to point to it.
80 */
81 struct Testvfs {
82   char *zName;                    /* Name of this VFS */
83   sqlite3_vfs *pParent;           /* The VFS to use for file IO */
84   sqlite3_vfs *pVfs;              /* The testvfs registered with SQLite */
85   Tcl_Interp *interp;             /* Interpreter to run script in */
86   Tcl_Obj *pScript;               /* Script to execute */
87   TestvfsBuffer *pBuffer;         /* List of shared buffers */
88   int isNoshm;
89   int isFullshm;
90 
91   int mask;                       /* Mask controlling [script] and [ioerr] */
92 
93   TestFaultInject ioerr_err;
94   TestFaultInject full_err;
95   TestFaultInject cantopen_err;
96 
97 #if 0
98   int iIoerrCnt;
99   int ioerr;
100   int nIoerrFail;
101   int iFullCnt;
102   int fullerr;
103   int nFullFail;
104 #endif
105 
106   int iDevchar;
107   int iSectorsize;
108 };
109 
110 /*
111 ** The Testvfs.mask variable is set to a combination of the following.
112 ** If a bit is clear in Testvfs.mask, then calls made by SQLite to the
113 ** corresponding VFS method is ignored for purposes of:
114 **
115 **   + Simulating IO errors, and
116 **   + Invoking the Tcl callback script.
117 */
118 #define TESTVFS_SHMOPEN_MASK      0x00000001
119 #define TESTVFS_SHMLOCK_MASK      0x00000010
120 #define TESTVFS_SHMMAP_MASK       0x00000020
121 #define TESTVFS_SHMBARRIER_MASK   0x00000040
122 #define TESTVFS_SHMCLOSE_MASK     0x00000080
123 
124 #define TESTVFS_OPEN_MASK         0x00000100
125 #define TESTVFS_SYNC_MASK         0x00000200
126 #define TESTVFS_DELETE_MASK       0x00000400
127 #define TESTVFS_CLOSE_MASK        0x00000800
128 #define TESTVFS_WRITE_MASK        0x00001000
129 #define TESTVFS_TRUNCATE_MASK     0x00002000
130 #define TESTVFS_ACCESS_MASK       0x00004000
131 #define TESTVFS_FULLPATHNAME_MASK 0x00008000
132 #define TESTVFS_READ_MASK         0x00010000
133 #define TESTVFS_UNLOCK_MASK       0x00020000
134 #define TESTVFS_LOCK_MASK         0x00040000
135 #define TESTVFS_CKLOCK_MASK       0x00080000
136 #define TESTVFS_FCNTL_MASK        0x00100000
137 
138 #define TESTVFS_ALL_MASK          0x001FFFFF
139 
140 
141 #define TESTVFS_MAX_PAGES 1024
142 
143 /*
144 ** A shared-memory buffer. There is one of these objects for each shared
145 ** memory region opened by clients. If two clients open the same file,
146 ** there are two TestvfsFile structures but only one TestvfsBuffer structure.
147 */
148 struct TestvfsBuffer {
149   char *zFile;                    /* Associated file name */
150   int pgsz;                       /* Page size */
151   u8 *aPage[TESTVFS_MAX_PAGES];   /* Array of ckalloc'd pages */
152   TestvfsFd *pFile;               /* List of open handles */
153   TestvfsBuffer *pNext;           /* Next in linked list of all buffers */
154 };
155 
156 
157 #define PARENTVFS(x) (((Testvfs *)((x)->pAppData))->pParent)
158 
159 #define TESTVFS_MAX_ARGS 12
160 
161 
162 /*
163 ** Method declarations for TestvfsFile.
164 */
165 static int tvfsClose(sqlite3_file*);
166 static int tvfsRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
167 static int tvfsWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
168 static int tvfsTruncate(sqlite3_file*, sqlite3_int64 size);
169 static int tvfsSync(sqlite3_file*, int flags);
170 static int tvfsFileSize(sqlite3_file*, sqlite3_int64 *pSize);
171 static int tvfsLock(sqlite3_file*, int);
172 static int tvfsUnlock(sqlite3_file*, int);
173 static int tvfsCheckReservedLock(sqlite3_file*, int *);
174 static int tvfsFileControl(sqlite3_file*, int op, void *pArg);
175 static int tvfsSectorSize(sqlite3_file*);
176 static int tvfsDeviceCharacteristics(sqlite3_file*);
177 
178 /*
179 ** Method declarations for tvfs_vfs.
180 */
181 static int tvfsOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
182 static int tvfsDelete(sqlite3_vfs*, const char *zName, int syncDir);
183 static int tvfsAccess(sqlite3_vfs*, const char *zName, int flags, int *);
184 static int tvfsFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
185 #ifndef SQLITE_OMIT_LOAD_EXTENSION
186 static void *tvfsDlOpen(sqlite3_vfs*, const char *zFilename);
187 static void tvfsDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
188 static void (*tvfsDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
189 static void tvfsDlClose(sqlite3_vfs*, void*);
190 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
191 static int tvfsRandomness(sqlite3_vfs*, int nByte, char *zOut);
192 static int tvfsSleep(sqlite3_vfs*, int microseconds);
193 static int tvfsCurrentTime(sqlite3_vfs*, double*);
194 
195 static int tvfsShmOpen(sqlite3_file*);
196 static int tvfsShmLock(sqlite3_file*, int , int, int);
197 static int tvfsShmMap(sqlite3_file*,int,int,int, void volatile **);
198 static void tvfsShmBarrier(sqlite3_file*);
199 static int tvfsShmUnmap(sqlite3_file*, int);
200 
201 static int tvfsFetch(sqlite3_file*, sqlite3_int64, int, void**);
202 static int tvfsUnfetch(sqlite3_file*, sqlite3_int64, void*);
203 
204 static sqlite3_io_methods tvfs_io_methods = {
205   3,                              /* iVersion */
206   tvfsClose,                      /* xClose */
207   tvfsRead,                       /* xRead */
208   tvfsWrite,                      /* xWrite */
209   tvfsTruncate,                   /* xTruncate */
210   tvfsSync,                       /* xSync */
211   tvfsFileSize,                   /* xFileSize */
212   tvfsLock,                       /* xLock */
213   tvfsUnlock,                     /* xUnlock */
214   tvfsCheckReservedLock,          /* xCheckReservedLock */
215   tvfsFileControl,                /* xFileControl */
216   tvfsSectorSize,                 /* xSectorSize */
217   tvfsDeviceCharacteristics,      /* xDeviceCharacteristics */
218   tvfsShmMap,                     /* xShmMap */
219   tvfsShmLock,                    /* xShmLock */
220   tvfsShmBarrier,                 /* xShmBarrier */
221   tvfsShmUnmap,                   /* xShmUnmap */
222   tvfsFetch,
223   tvfsUnfetch
224 };
225 
226 static int tvfsResultCode(Testvfs *p, int *pRc){
227   struct errcode {
228     int eCode;
229     const char *zCode;
230   } aCode[] = {
231     { SQLITE_OK,       "SQLITE_OK"     },
232     { SQLITE_ERROR,    "SQLITE_ERROR"  },
233     { SQLITE_IOERR,    "SQLITE_IOERR"  },
234     { SQLITE_LOCKED,   "SQLITE_LOCKED" },
235     { SQLITE_BUSY,     "SQLITE_BUSY"   },
236     { SQLITE_READONLY, "SQLITE_READONLY"   },
237   };
238 
239   const char *z;
240   int i;
241 
242   z = Tcl_GetStringResult(p->interp);
243   for(i=0; i<ArraySize(aCode); i++){
244     if( 0==strcmp(z, aCode[i].zCode) ){
245       *pRc = aCode[i].eCode;
246       return 1;
247     }
248   }
249 
250   return 0;
251 }
252 
253 static int tvfsInjectFault(TestFaultInject *p){
254   int ret = 0;
255   if( p->eFault ){
256     p->iCnt--;
257     if( p->iCnt==0 || (p->iCnt<0 && p->eFault==FAULT_INJECT_PERSISTENT ) ){
258       ret = 1;
259       p->nFail++;
260     }
261   }
262   return ret;
263 }
264 
265 
266 static int tvfsInjectIoerr(Testvfs *p){
267   return tvfsInjectFault(&p->ioerr_err);
268 }
269 
270 static int tvfsInjectFullerr(Testvfs *p){
271   return tvfsInjectFault(&p->full_err);
272 }
273 static int tvfsInjectCantopenerr(Testvfs *p){
274   return tvfsInjectFault(&p->cantopen_err);
275 }
276 
277 
278 static void tvfsExecTcl(
279   Testvfs *p,
280   const char *zMethod,
281   Tcl_Obj *arg1,
282   Tcl_Obj *arg2,
283   Tcl_Obj *arg3,
284   Tcl_Obj *arg4
285 ){
286   int rc;                         /* Return code from Tcl_EvalObj() */
287   Tcl_Obj *pEval;
288   assert( p->pScript );
289 
290   assert( zMethod );
291   assert( p );
292   assert( arg2==0 || arg1!=0 );
293   assert( arg3==0 || arg2!=0 );
294 
295   pEval = Tcl_DuplicateObj(p->pScript);
296   Tcl_IncrRefCount(p->pScript);
297   Tcl_ListObjAppendElement(p->interp, pEval, Tcl_NewStringObj(zMethod, -1));
298   if( arg1 ) Tcl_ListObjAppendElement(p->interp, pEval, arg1);
299   if( arg2 ) Tcl_ListObjAppendElement(p->interp, pEval, arg2);
300   if( arg3 ) Tcl_ListObjAppendElement(p->interp, pEval, arg3);
301   if( arg4 ) Tcl_ListObjAppendElement(p->interp, pEval, arg4);
302 
303   rc = Tcl_EvalObjEx(p->interp, pEval, TCL_EVAL_GLOBAL);
304   if( rc!=TCL_OK ){
305     Tcl_BackgroundError(p->interp);
306     Tcl_ResetResult(p->interp);
307   }
308 }
309 
310 
311 /*
312 ** Close an tvfs-file.
313 */
314 static int tvfsClose(sqlite3_file *pFile){
315   TestvfsFile *pTestfile = (TestvfsFile *)pFile;
316   TestvfsFd *pFd = pTestfile->pFd;
317   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
318 
319   if( p->pScript && p->mask&TESTVFS_CLOSE_MASK ){
320     tvfsExecTcl(p, "xClose",
321         Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0, 0
322     );
323   }
324 
325   if( pFd->pShmId ){
326     Tcl_DecrRefCount(pFd->pShmId);
327     pFd->pShmId = 0;
328   }
329   if( pFile->pMethods ){
330     ckfree((char *)pFile->pMethods);
331   }
332   sqlite3OsClose(pFd->pReal);
333   ckfree((char *)pFd);
334   pTestfile->pFd = 0;
335   return SQLITE_OK;
336 }
337 
338 /*
339 ** Read data from an tvfs-file.
340 */
341 static int tvfsRead(
342   sqlite3_file *pFile,
343   void *zBuf,
344   int iAmt,
345   sqlite_int64 iOfst
346 ){
347   int rc = SQLITE_OK;
348   TestvfsFd *pFd = tvfsGetFd(pFile);
349   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
350   if( p->pScript && p->mask&TESTVFS_READ_MASK ){
351     tvfsExecTcl(p, "xRead",
352         Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0, 0
353     );
354     tvfsResultCode(p, &rc);
355   }
356   if( rc==SQLITE_OK && p->mask&TESTVFS_READ_MASK && tvfsInjectIoerr(p) ){
357     rc = SQLITE_IOERR;
358   }
359   if( rc==SQLITE_OK ){
360     rc = sqlite3OsRead(pFd->pReal, zBuf, iAmt, iOfst);
361   }
362   return rc;
363 }
364 
365 /*
366 ** Write data to an tvfs-file.
367 */
368 static int tvfsWrite(
369   sqlite3_file *pFile,
370   const void *zBuf,
371   int iAmt,
372   sqlite_int64 iOfst
373 ){
374   int rc = SQLITE_OK;
375   TestvfsFd *pFd = tvfsGetFd(pFile);
376   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
377 
378   if( p->pScript && p->mask&TESTVFS_WRITE_MASK ){
379     tvfsExecTcl(p, "xWrite",
380         Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId,
381         Tcl_NewWideIntObj(iOfst), Tcl_NewIntObj(iAmt)
382     );
383     tvfsResultCode(p, &rc);
384   }
385 
386   if( rc==SQLITE_OK && tvfsInjectFullerr(p) ){
387     rc = SQLITE_FULL;
388   }
389   if( rc==SQLITE_OK && p->mask&TESTVFS_WRITE_MASK && tvfsInjectIoerr(p) ){
390     rc = SQLITE_IOERR;
391   }
392 
393   if( rc==SQLITE_OK ){
394     rc = sqlite3OsWrite(pFd->pReal, zBuf, iAmt, iOfst);
395   }
396   return rc;
397 }
398 
399 /*
400 ** Truncate an tvfs-file.
401 */
402 static int tvfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
403   int rc = SQLITE_OK;
404   TestvfsFd *pFd = tvfsGetFd(pFile);
405   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
406 
407   if( p->pScript && p->mask&TESTVFS_TRUNCATE_MASK ){
408     tvfsExecTcl(p, "xTruncate",
409         Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0, 0
410     );
411     tvfsResultCode(p, &rc);
412   }
413 
414   if( rc==SQLITE_OK ){
415     rc = sqlite3OsTruncate(pFd->pReal, size);
416   }
417   return rc;
418 }
419 
420 /*
421 ** Sync an tvfs-file.
422 */
423 static int tvfsSync(sqlite3_file *pFile, int flags){
424   int rc = SQLITE_OK;
425   TestvfsFd *pFd = tvfsGetFd(pFile);
426   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
427 
428   if( p->pScript && p->mask&TESTVFS_SYNC_MASK ){
429     char *zFlags = 0;
430 
431     switch( flags ){
432       case SQLITE_SYNC_NORMAL:
433         zFlags = "normal";
434         break;
435       case SQLITE_SYNC_FULL:
436         zFlags = "full";
437         break;
438       case SQLITE_SYNC_NORMAL|SQLITE_SYNC_DATAONLY:
439         zFlags = "normal|dataonly";
440         break;
441       case SQLITE_SYNC_FULL|SQLITE_SYNC_DATAONLY:
442         zFlags = "full|dataonly";
443         break;
444       default:
445         assert(0);
446     }
447 
448     tvfsExecTcl(p, "xSync",
449         Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId,
450         Tcl_NewStringObj(zFlags, -1), 0
451     );
452     tvfsResultCode(p, &rc);
453   }
454 
455   if( rc==SQLITE_OK && tvfsInjectFullerr(p) ) rc = SQLITE_FULL;
456 
457   if( rc==SQLITE_OK ){
458     rc = sqlite3OsSync(pFd->pReal, flags);
459   }
460 
461   return rc;
462 }
463 
464 /*
465 ** Return the current file-size of an tvfs-file.
466 */
467 static int tvfsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
468   TestvfsFd *p = tvfsGetFd(pFile);
469   return sqlite3OsFileSize(p->pReal, pSize);
470 }
471 
472 /*
473 ** Lock an tvfs-file.
474 */
475 static int tvfsLock(sqlite3_file *pFile, int eLock){
476   TestvfsFd *pFd = tvfsGetFd(pFile);
477   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
478   if( p->pScript && p->mask&TESTVFS_LOCK_MASK ){
479     char zLock[30];
480     sqlite3_snprintf(sizeof(zLock),zLock,"%d",eLock);
481     tvfsExecTcl(p, "xLock", Tcl_NewStringObj(pFd->zFilename, -1),
482                    Tcl_NewStringObj(zLock, -1), 0, 0);
483   }
484   return sqlite3OsLock(pFd->pReal, eLock);
485 }
486 
487 /*
488 ** Unlock an tvfs-file.
489 */
490 static int tvfsUnlock(sqlite3_file *pFile, int eLock){
491   TestvfsFd *pFd = tvfsGetFd(pFile);
492   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
493   if( p->pScript && p->mask&TESTVFS_UNLOCK_MASK ){
494     char zLock[30];
495     sqlite3_snprintf(sizeof(zLock),zLock,"%d",eLock);
496     tvfsExecTcl(p, "xUnlock", Tcl_NewStringObj(pFd->zFilename, -1),
497                    Tcl_NewStringObj(zLock, -1), 0, 0);
498   }
499   if( p->mask&TESTVFS_WRITE_MASK && tvfsInjectIoerr(p) ){
500     return SQLITE_IOERR_UNLOCK;
501   }
502   return sqlite3OsUnlock(pFd->pReal, eLock);
503 }
504 
505 /*
506 ** Check if another file-handle holds a RESERVED lock on an tvfs-file.
507 */
508 static int tvfsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
509   TestvfsFd *pFd = tvfsGetFd(pFile);
510   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
511   if( p->pScript && p->mask&TESTVFS_CKLOCK_MASK ){
512     tvfsExecTcl(p, "xCheckReservedLock", Tcl_NewStringObj(pFd->zFilename, -1),
513                    0, 0, 0);
514   }
515   return sqlite3OsCheckReservedLock(pFd->pReal, pResOut);
516 }
517 
518 /*
519 ** File control method. For custom operations on an tvfs-file.
520 */
521 static int tvfsFileControl(sqlite3_file *pFile, int op, void *pArg){
522   TestvfsFd *pFd = tvfsGetFd(pFile);
523   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
524   if( op==SQLITE_FCNTL_PRAGMA ){
525     char **argv = (char**)pArg;
526     if( sqlite3_stricmp(argv[1],"error")==0 ){
527       int rc = SQLITE_ERROR;
528       if( argv[2] ){
529         const char *z = argv[2];
530         int x = atoi(z);
531         if( x ){
532           rc = x;
533           while( sqlite3Isdigit(z[0]) ){ z++; }
534           while( sqlite3Isspace(z[0]) ){ z++; }
535         }
536         if( z[0] ) argv[0] = sqlite3_mprintf("%s", z);
537       }
538       return rc;
539     }
540     if( sqlite3_stricmp(argv[1], "filename")==0 ){
541       argv[0] = sqlite3_mprintf("%s", pFd->zFilename);
542       return SQLITE_OK;
543     }
544   }
545   if( p->pScript && (p->mask&TESTVFS_FCNTL_MASK) ){
546     struct Fcntl {
547       int iFnctl;
548       const char *zFnctl;
549     } aF[] = {
550       { SQLITE_FCNTL_BEGIN_ATOMIC_WRITE, "BEGIN_ATOMIC_WRITE" },
551       { SQLITE_FCNTL_COMMIT_ATOMIC_WRITE, "COMMIT_ATOMIC_WRITE" },
552     };
553     int i;
554     for(i=0; i<sizeof(aF)/sizeof(aF[0]); i++){
555       if( op==aF[i].iFnctl ) break;
556     }
557     if( i<sizeof(aF)/sizeof(aF[0]) ){
558       int rc = 0;
559       tvfsExecTcl(p, "xFileControl",
560           Tcl_NewStringObj(pFd->zFilename, -1),
561           Tcl_NewStringObj(aF[i].zFnctl, -1),
562           0, 0
563       );
564       tvfsResultCode(p, &rc);
565       if( rc ) return rc;
566     }
567   }
568   return sqlite3OsFileControl(pFd->pReal, op, pArg);
569 }
570 
571 /*
572 ** Return the sector-size in bytes for an tvfs-file.
573 */
574 static int tvfsSectorSize(sqlite3_file *pFile){
575   TestvfsFd *pFd = tvfsGetFd(pFile);
576   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
577   if( p->iSectorsize>=0 ){
578     return p->iSectorsize;
579   }
580   return sqlite3OsSectorSize(pFd->pReal);
581 }
582 
583 /*
584 ** Return the device characteristic flags supported by an tvfs-file.
585 */
586 static int tvfsDeviceCharacteristics(sqlite3_file *pFile){
587   TestvfsFd *pFd = tvfsGetFd(pFile);
588   Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
589   if( p->iDevchar>=0 ){
590     return p->iDevchar;
591   }
592   return sqlite3OsDeviceCharacteristics(pFd->pReal);
593 }
594 
595 /*
596 ** Open an tvfs file handle.
597 */
598 static int tvfsOpen(
599   sqlite3_vfs *pVfs,
600   const char *zName,
601   sqlite3_file *pFile,
602   int flags,
603   int *pOutFlags
604 ){
605   int rc;
606   TestvfsFile *pTestfile = (TestvfsFile *)pFile;
607   TestvfsFd *pFd;
608   Tcl_Obj *pId = 0;
609   Testvfs *p = (Testvfs *)pVfs->pAppData;
610 
611   pFd = (TestvfsFd *)ckalloc(sizeof(TestvfsFd) + PARENTVFS(pVfs)->szOsFile);
612   memset(pFd, 0, sizeof(TestvfsFd) + PARENTVFS(pVfs)->szOsFile);
613   pFd->pShm = 0;
614   pFd->pShmId = 0;
615   pFd->zFilename = zName;
616   pFd->pVfs = pVfs;
617   pFd->pReal = (sqlite3_file *)&pFd[1];
618   memset(pTestfile, 0, sizeof(TestvfsFile));
619   pTestfile->pFd = pFd;
620 
621   /* Evaluate the Tcl script:
622   **
623   **   SCRIPT xOpen FILENAME KEY-VALUE-ARGS
624   **
625   ** If the script returns an SQLite error code other than SQLITE_OK, an
626   ** error is returned to the caller. If it returns SQLITE_OK, the new
627   ** connection is named "anon". Otherwise, the value returned by the
628   ** script is used as the connection name.
629   */
630   Tcl_ResetResult(p->interp);
631   if( p->pScript && p->mask&TESTVFS_OPEN_MASK ){
632     Tcl_Obj *pArg = Tcl_NewObj();
633     Tcl_IncrRefCount(pArg);
634     if( flags&SQLITE_OPEN_MAIN_DB ){
635       const char *z = &zName[strlen(zName)+1];
636       while( *z ){
637         Tcl_ListObjAppendElement(0, pArg, Tcl_NewStringObj(z, -1));
638         z += strlen(z) + 1;
639         Tcl_ListObjAppendElement(0, pArg, Tcl_NewStringObj(z, -1));
640         z += strlen(z) + 1;
641       }
642     }
643     tvfsExecTcl(p, "xOpen", Tcl_NewStringObj(pFd->zFilename, -1), pArg, 0, 0);
644     Tcl_DecrRefCount(pArg);
645     if( tvfsResultCode(p, &rc) ){
646       if( rc!=SQLITE_OK ) return rc;
647     }else{
648       pId = Tcl_GetObjResult(p->interp);
649     }
650   }
651 
652   if( (p->mask&TESTVFS_OPEN_MASK) &&  tvfsInjectIoerr(p) ) return SQLITE_IOERR;
653   if( tvfsInjectCantopenerr(p) ) return SQLITE_CANTOPEN;
654   if( tvfsInjectFullerr(p) ) return SQLITE_FULL;
655 
656   if( !pId ){
657     pId = Tcl_NewStringObj("anon", -1);
658   }
659   Tcl_IncrRefCount(pId);
660   pFd->pShmId = pId;
661   Tcl_ResetResult(p->interp);
662 
663   rc = sqlite3OsOpen(PARENTVFS(pVfs), zName, pFd->pReal, flags, pOutFlags);
664   if( pFd->pReal->pMethods ){
665     sqlite3_io_methods *pMethods;
666     int nByte;
667 
668     if( pVfs->iVersion>1 ){
669       nByte = sizeof(sqlite3_io_methods);
670     }else{
671       nByte = offsetof(sqlite3_io_methods, xShmMap);
672     }
673 
674     pMethods = (sqlite3_io_methods *)ckalloc(nByte);
675     memcpy(pMethods, &tvfs_io_methods, nByte);
676     pMethods->iVersion = pFd->pReal->pMethods->iVersion;
677     if( pMethods->iVersion>pVfs->iVersion ){
678       pMethods->iVersion = pVfs->iVersion;
679     }
680     if( pVfs->iVersion>1 && ((Testvfs *)pVfs->pAppData)->isNoshm ){
681       pMethods->xShmUnmap = 0;
682       pMethods->xShmLock = 0;
683       pMethods->xShmBarrier = 0;
684       pMethods->xShmMap = 0;
685     }
686     pFile->pMethods = pMethods;
687   }
688 
689   return rc;
690 }
691 
692 /*
693 ** Delete the file located at zPath. If the dirSync argument is true,
694 ** ensure the file-system modifications are synced to disk before
695 ** returning.
696 */
697 static int tvfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
698   int rc = SQLITE_OK;
699   Testvfs *p = (Testvfs *)pVfs->pAppData;
700 
701   if( p->pScript && p->mask&TESTVFS_DELETE_MASK ){
702     tvfsExecTcl(p, "xDelete",
703         Tcl_NewStringObj(zPath, -1), Tcl_NewIntObj(dirSync), 0, 0
704     );
705     tvfsResultCode(p, &rc);
706   }
707   if( rc==SQLITE_OK ){
708     rc = sqlite3OsDelete(PARENTVFS(pVfs), zPath, dirSync);
709   }
710   return rc;
711 }
712 
713 /*
714 ** Test for access permissions. Return true if the requested permission
715 ** is available, or false otherwise.
716 */
717 static int tvfsAccess(
718   sqlite3_vfs *pVfs,
719   const char *zPath,
720   int flags,
721   int *pResOut
722 ){
723   Testvfs *p = (Testvfs *)pVfs->pAppData;
724   if( p->pScript && p->mask&TESTVFS_ACCESS_MASK ){
725     int rc;
726     char *zArg = 0;
727     if( flags==SQLITE_ACCESS_EXISTS ) zArg = "SQLITE_ACCESS_EXISTS";
728     if( flags==SQLITE_ACCESS_READWRITE ) zArg = "SQLITE_ACCESS_READWRITE";
729     if( flags==SQLITE_ACCESS_READ ) zArg = "SQLITE_ACCESS_READ";
730     tvfsExecTcl(p, "xAccess",
731         Tcl_NewStringObj(zPath, -1), Tcl_NewStringObj(zArg, -1), 0, 0
732     );
733     if( tvfsResultCode(p, &rc) ){
734       if( rc!=SQLITE_OK ) return rc;
735     }else{
736       Tcl_Interp *interp = p->interp;
737       if( TCL_OK==Tcl_GetBooleanFromObj(0, Tcl_GetObjResult(interp), pResOut) ){
738         return SQLITE_OK;
739       }
740     }
741   }
742   return sqlite3OsAccess(PARENTVFS(pVfs), zPath, flags, pResOut);
743 }
744 
745 /*
746 ** Populate buffer zOut with the full canonical pathname corresponding
747 ** to the pathname in zPath. zOut is guaranteed to point to a buffer
748 ** of at least (DEVSYM_MAX_PATHNAME+1) bytes.
749 */
750 static int tvfsFullPathname(
751   sqlite3_vfs *pVfs,
752   const char *zPath,
753   int nOut,
754   char *zOut
755 ){
756   Testvfs *p = (Testvfs *)pVfs->pAppData;
757   if( p->pScript && p->mask&TESTVFS_FULLPATHNAME_MASK ){
758     int rc;
759     tvfsExecTcl(p, "xFullPathname", Tcl_NewStringObj(zPath, -1), 0, 0, 0);
760     if( tvfsResultCode(p, &rc) ){
761       if( rc!=SQLITE_OK ) return rc;
762     }
763   }
764   return sqlite3OsFullPathname(PARENTVFS(pVfs), zPath, nOut, zOut);
765 }
766 
767 #ifndef SQLITE_OMIT_LOAD_EXTENSION
768 /*
769 ** Open the dynamic library located at zPath and return a handle.
770 */
771 static void *tvfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
772   return sqlite3OsDlOpen(PARENTVFS(pVfs), zPath);
773 }
774 
775 /*
776 ** Populate the buffer zErrMsg (size nByte bytes) with a human readable
777 ** utf-8 string describing the most recent error encountered associated
778 ** with dynamic libraries.
779 */
780 static void tvfsDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
781   sqlite3OsDlError(PARENTVFS(pVfs), nByte, zErrMsg);
782 }
783 
784 /*
785 ** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
786 */
787 static void (*tvfsDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
788   return sqlite3OsDlSym(PARENTVFS(pVfs), p, zSym);
789 }
790 
791 /*
792 ** Close the dynamic library handle pHandle.
793 */
794 static void tvfsDlClose(sqlite3_vfs *pVfs, void *pHandle){
795   sqlite3OsDlClose(PARENTVFS(pVfs), pHandle);
796 }
797 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
798 
799 /*
800 ** Populate the buffer pointed to by zBufOut with nByte bytes of
801 ** random data.
802 */
803 static int tvfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
804   return sqlite3OsRandomness(PARENTVFS(pVfs), nByte, zBufOut);
805 }
806 
807 /*
808 ** Sleep for nMicro microseconds. Return the number of microseconds
809 ** actually slept.
810 */
811 static int tvfsSleep(sqlite3_vfs *pVfs, int nMicro){
812   return sqlite3OsSleep(PARENTVFS(pVfs), nMicro);
813 }
814 
815 /*
816 ** Return the current time as a Julian Day number in *pTimeOut.
817 */
818 static int tvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
819   return PARENTVFS(pVfs)->xCurrentTime(PARENTVFS(pVfs), pTimeOut);
820 }
821 
822 static int tvfsShmOpen(sqlite3_file *pFile){
823   Testvfs *p;
824   int rc = SQLITE_OK;             /* Return code */
825   TestvfsBuffer *pBuffer;         /* Buffer to open connection to */
826   TestvfsFd *pFd;                 /* The testvfs file structure */
827 
828   pFd = tvfsGetFd(pFile);
829   p = (Testvfs *)pFd->pVfs->pAppData;
830   assert( 0==p->isFullshm );
831   assert( pFd->pShmId && pFd->pShm==0 && pFd->pNext==0 );
832 
833   /* Evaluate the Tcl script:
834   **
835   **   SCRIPT xShmOpen FILENAME
836   */
837   Tcl_ResetResult(p->interp);
838   if( p->pScript && p->mask&TESTVFS_SHMOPEN_MASK ){
839     tvfsExecTcl(p, "xShmOpen", Tcl_NewStringObj(pFd->zFilename, -1), 0, 0, 0);
840     if( tvfsResultCode(p, &rc) ){
841       if( rc!=SQLITE_OK ) return rc;
842     }
843   }
844 
845   assert( rc==SQLITE_OK );
846   if( p->mask&TESTVFS_SHMOPEN_MASK && tvfsInjectIoerr(p) ){
847     return SQLITE_IOERR;
848   }
849 
850   /* Search for a TestvfsBuffer. Create a new one if required. */
851   for(pBuffer=p->pBuffer; pBuffer; pBuffer=pBuffer->pNext){
852     if( 0==strcmp(pFd->zFilename, pBuffer->zFile) ) break;
853   }
854   if( !pBuffer ){
855     int szName = (int)strlen(pFd->zFilename);
856     int nByte = sizeof(TestvfsBuffer) + szName + 1;
857     pBuffer = (TestvfsBuffer *)ckalloc(nByte);
858     memset(pBuffer, 0, nByte);
859     pBuffer->zFile = (char *)&pBuffer[1];
860     memcpy(pBuffer->zFile, pFd->zFilename, szName+1);
861     pBuffer->pNext = p->pBuffer;
862     p->pBuffer = pBuffer;
863   }
864 
865   /* Connect the TestvfsBuffer to the new TestvfsShm handle and return. */
866   pFd->pNext = pBuffer->pFile;
867   pBuffer->pFile = pFd;
868   pFd->pShm = pBuffer;
869   return rc;
870 }
871 
872 static void tvfsAllocPage(TestvfsBuffer *p, int iPage, int pgsz){
873   assert( iPage<TESTVFS_MAX_PAGES );
874   if( p->aPage[iPage]==0 ){
875     p->aPage[iPage] = (u8 *)ckalloc(pgsz);
876     memset(p->aPage[iPage], 0, pgsz);
877     p->pgsz = pgsz;
878   }
879 }
880 
881 static int tvfsShmMap(
882   sqlite3_file *pFile,            /* Handle open on database file */
883   int iPage,                      /* Page to retrieve */
884   int pgsz,                       /* Size of pages */
885   int isWrite,                    /* True to extend file if necessary */
886   void volatile **pp              /* OUT: Mapped memory */
887 ){
888   int rc = SQLITE_OK;
889   TestvfsFd *pFd = tvfsGetFd(pFile);
890   Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);
891 
892   if( p->isFullshm ){
893     return sqlite3OsShmMap(pFd->pReal, iPage, pgsz, isWrite, pp);
894   }
895 
896   if( 0==pFd->pShm ){
897     rc = tvfsShmOpen(pFile);
898     if( rc!=SQLITE_OK ){
899       return rc;
900     }
901   }
902 
903   if( p->pScript && p->mask&TESTVFS_SHMMAP_MASK ){
904     Tcl_Obj *pArg = Tcl_NewObj();
905     Tcl_IncrRefCount(pArg);
906     Tcl_ListObjAppendElement(p->interp, pArg, Tcl_NewIntObj(iPage));
907     Tcl_ListObjAppendElement(p->interp, pArg, Tcl_NewIntObj(pgsz));
908     Tcl_ListObjAppendElement(p->interp, pArg, Tcl_NewIntObj(isWrite));
909     tvfsExecTcl(p, "xShmMap",
910         Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId, pArg, 0
911     );
912     tvfsResultCode(p, &rc);
913     Tcl_DecrRefCount(pArg);
914   }
915   if( rc==SQLITE_OK && p->mask&TESTVFS_SHMMAP_MASK && tvfsInjectIoerr(p) ){
916     rc = SQLITE_IOERR;
917   }
918 
919   if( rc==SQLITE_OK && isWrite && !pFd->pShm->aPage[iPage] ){
920     tvfsAllocPage(pFd->pShm, iPage, pgsz);
921   }
922   *pp = (void volatile *)pFd->pShm->aPage[iPage];
923 
924   return rc;
925 }
926 
927 
928 static int tvfsShmLock(
929   sqlite3_file *pFile,
930   int ofst,
931   int n,
932   int flags
933 ){
934   int rc = SQLITE_OK;
935   TestvfsFd *pFd = tvfsGetFd(pFile);
936   Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);
937   int nLock;
938   char zLock[80];
939 
940   if( p->isFullshm ){
941     return sqlite3OsShmLock(pFd->pReal, ofst, n, flags);
942   }
943 
944   if( p->pScript && p->mask&TESTVFS_SHMLOCK_MASK ){
945     sqlite3_snprintf(sizeof(zLock), zLock, "%d %d", ofst, n);
946     nLock = (int)strlen(zLock);
947     if( flags & SQLITE_SHM_LOCK ){
948       strcpy(&zLock[nLock], " lock");
949     }else{
950       strcpy(&zLock[nLock], " unlock");
951     }
952     nLock += (int)strlen(&zLock[nLock]);
953     if( flags & SQLITE_SHM_SHARED ){
954       strcpy(&zLock[nLock], " shared");
955     }else{
956       strcpy(&zLock[nLock], " exclusive");
957     }
958     tvfsExecTcl(p, "xShmLock",
959         Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId,
960         Tcl_NewStringObj(zLock, -1), 0
961     );
962     tvfsResultCode(p, &rc);
963   }
964 
965   if( rc==SQLITE_OK && p->mask&TESTVFS_SHMLOCK_MASK && tvfsInjectIoerr(p) ){
966     rc = SQLITE_IOERR;
967   }
968 
969   if( rc==SQLITE_OK ){
970     int isLock = (flags & SQLITE_SHM_LOCK);
971     int isExcl = (flags & SQLITE_SHM_EXCLUSIVE);
972     u32 mask = (((1<<n)-1) << ofst);
973     if( isLock ){
974       TestvfsFd *p2;
975       for(p2=pFd->pShm->pFile; p2; p2=p2->pNext){
976         if( p2==pFd ) continue;
977         if( (p2->excllock&mask) || (isExcl && p2->sharedlock&mask) ){
978           rc = SQLITE_BUSY;
979           break;
980         }
981       }
982       if( rc==SQLITE_OK ){
983         if( isExcl )  pFd->excllock |= mask;
984         if( !isExcl ) pFd->sharedlock |= mask;
985       }
986     }else{
987       if( isExcl )  pFd->excllock &= (~mask);
988       if( !isExcl ) pFd->sharedlock &= (~mask);
989     }
990   }
991 
992   return rc;
993 }
994 
995 static void tvfsShmBarrier(sqlite3_file *pFile){
996   TestvfsFd *pFd = tvfsGetFd(pFile);
997   Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);
998 
999   if( p->pScript && p->mask&TESTVFS_SHMBARRIER_MASK ){
1000     const char *z = pFd->pShm ? pFd->pShm->zFile : "";
1001     tvfsExecTcl(p, "xShmBarrier", Tcl_NewStringObj(z, -1), pFd->pShmId, 0, 0);
1002   }
1003 
1004   if( p->isFullshm ){
1005     sqlite3OsShmBarrier(pFd->pReal);
1006     return;
1007   }
1008 }
1009 
1010 static int tvfsShmUnmap(
1011   sqlite3_file *pFile,
1012   int deleteFlag
1013 ){
1014   int rc = SQLITE_OK;
1015   TestvfsFd *pFd = tvfsGetFd(pFile);
1016   Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);
1017   TestvfsBuffer *pBuffer = pFd->pShm;
1018   TestvfsFd **ppFd;
1019 
1020   if( p->isFullshm ){
1021     return sqlite3OsShmUnmap(pFd->pReal, deleteFlag);
1022   }
1023 
1024   if( !pBuffer ) return SQLITE_OK;
1025   assert( pFd->pShmId && pFd->pShm );
1026 
1027   if( p->pScript && p->mask&TESTVFS_SHMCLOSE_MASK ){
1028     tvfsExecTcl(p, "xShmUnmap",
1029         Tcl_NewStringObj(pFd->pShm->zFile, -1), pFd->pShmId, 0, 0
1030     );
1031     tvfsResultCode(p, &rc);
1032   }
1033 
1034   for(ppFd=&pBuffer->pFile; *ppFd!=pFd; ppFd=&((*ppFd)->pNext));
1035   assert( (*ppFd)==pFd );
1036   *ppFd = pFd->pNext;
1037   pFd->pNext = 0;
1038 
1039   if( pBuffer->pFile==0 ){
1040     int i;
1041     TestvfsBuffer **pp;
1042     for(pp=&p->pBuffer; *pp!=pBuffer; pp=&((*pp)->pNext));
1043     *pp = (*pp)->pNext;
1044     for(i=0; pBuffer->aPage[i]; i++){
1045       ckfree((char *)pBuffer->aPage[i]);
1046     }
1047     ckfree((char *)pBuffer);
1048   }
1049   pFd->pShm = 0;
1050 
1051   return rc;
1052 }
1053 
1054 static int tvfsFetch(
1055     sqlite3_file *pFile,
1056     sqlite3_int64 iOfst,
1057     int iAmt,
1058     void **pp
1059 ){
1060   TestvfsFd *pFd = tvfsGetFd(pFile);
1061   return sqlite3OsFetch(pFd->pReal, iOfst, iAmt, pp);
1062 }
1063 
1064 static int tvfsUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *p){
1065   TestvfsFd *pFd = tvfsGetFd(pFile);
1066   return sqlite3OsUnfetch(pFd->pReal, iOfst, p);
1067 }
1068 
1069 static int SQLITE_TCLAPI testvfs_obj_cmd(
1070   ClientData cd,
1071   Tcl_Interp *interp,
1072   int objc,
1073   Tcl_Obj *CONST objv[]
1074 ){
1075   Testvfs *p = (Testvfs *)cd;
1076 
1077   enum DB_enum {
1078     CMD_SHM, CMD_DELETE, CMD_FILTER, CMD_IOERR, CMD_SCRIPT,
1079     CMD_DEVCHAR, CMD_SECTORSIZE, CMD_FULLERR, CMD_CANTOPENERR
1080   };
1081   struct TestvfsSubcmd {
1082     char *zName;
1083     enum DB_enum eCmd;
1084   } aSubcmd[] = {
1085     { "shm",         CMD_SHM         },
1086     { "delete",      CMD_DELETE      },
1087     { "filter",      CMD_FILTER      },
1088     { "ioerr",       CMD_IOERR       },
1089     { "fullerr",     CMD_FULLERR     },
1090     { "cantopenerr", CMD_CANTOPENERR },
1091     { "script",      CMD_SCRIPT      },
1092     { "devchar",     CMD_DEVCHAR     },
1093     { "sectorsize",  CMD_SECTORSIZE  },
1094     { 0, 0 }
1095   };
1096   int i;
1097 
1098   if( objc<2 ){
1099     Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
1100     return TCL_ERROR;
1101   }
1102   if( Tcl_GetIndexFromObjStruct(
1103         interp, objv[1], aSubcmd, sizeof(aSubcmd[0]), "subcommand", 0, &i)
1104   ){
1105     return TCL_ERROR;
1106   }
1107   Tcl_ResetResult(interp);
1108 
1109   switch( aSubcmd[i].eCmd ){
1110     case CMD_SHM: {
1111       Tcl_Obj *pObj;
1112       int rc;
1113       TestvfsBuffer *pBuffer;
1114       char *zName;
1115       if( objc!=3 && objc!=4 ){
1116         Tcl_WrongNumArgs(interp, 2, objv, "FILE ?VALUE?");
1117         return TCL_ERROR;
1118       }
1119       zName = ckalloc(p->pParent->mxPathname);
1120       rc = p->pParent->xFullPathname(
1121           p->pParent, Tcl_GetString(objv[2]),
1122           p->pParent->mxPathname, zName
1123       );
1124       if( rc!=SQLITE_OK ){
1125         Tcl_AppendResult(interp, "failed to get full path: ",
1126                          Tcl_GetString(objv[2]), 0);
1127         ckfree(zName);
1128         return TCL_ERROR;
1129       }
1130       for(pBuffer=p->pBuffer; pBuffer; pBuffer=pBuffer->pNext){
1131         if( 0==strcmp(pBuffer->zFile, zName) ) break;
1132       }
1133       ckfree(zName);
1134       if( !pBuffer ){
1135         Tcl_AppendResult(interp, "no such file: ", Tcl_GetString(objv[2]), 0);
1136         return TCL_ERROR;
1137       }
1138       if( objc==4 ){
1139         int n;
1140         u8 *a = Tcl_GetByteArrayFromObj(objv[3], &n);
1141         int pgsz = pBuffer->pgsz;
1142         if( pgsz==0 ) pgsz = 65536;
1143         for(i=0; i*pgsz<n; i++){
1144           int nByte = pgsz;
1145           tvfsAllocPage(pBuffer, i, pgsz);
1146           if( n-i*pgsz<pgsz ){
1147             nByte = n;
1148           }
1149           memcpy(pBuffer->aPage[i], &a[i*pgsz], nByte);
1150         }
1151       }
1152 
1153       pObj = Tcl_NewObj();
1154       for(i=0; pBuffer->aPage[i]; i++){
1155         int pgsz = pBuffer->pgsz;
1156         if( pgsz==0 ) pgsz = 65536;
1157         Tcl_AppendObjToObj(pObj, Tcl_NewByteArrayObj(pBuffer->aPage[i], pgsz));
1158       }
1159       Tcl_SetObjResult(interp, pObj);
1160       break;
1161     }
1162 
1163     /*  TESTVFS filter METHOD-LIST
1164     **
1165     **     Activate special processing for those methods contained in the list
1166     */
1167     case CMD_FILTER: {
1168       static struct VfsMethod {
1169         char *zName;
1170         int mask;
1171       } vfsmethod [] = {
1172         { "xShmOpen",           TESTVFS_SHMOPEN_MASK },
1173         { "xShmLock",           TESTVFS_SHMLOCK_MASK },
1174         { "xShmBarrier",        TESTVFS_SHMBARRIER_MASK },
1175         { "xShmUnmap",          TESTVFS_SHMCLOSE_MASK },
1176         { "xShmMap",            TESTVFS_SHMMAP_MASK },
1177         { "xSync",              TESTVFS_SYNC_MASK },
1178         { "xDelete",            TESTVFS_DELETE_MASK },
1179         { "xWrite",             TESTVFS_WRITE_MASK },
1180         { "xRead",              TESTVFS_READ_MASK },
1181         { "xTruncate",          TESTVFS_TRUNCATE_MASK },
1182         { "xOpen",              TESTVFS_OPEN_MASK },
1183         { "xClose",             TESTVFS_CLOSE_MASK },
1184         { "xAccess",            TESTVFS_ACCESS_MASK },
1185         { "xFullPathname",      TESTVFS_FULLPATHNAME_MASK },
1186         { "xUnlock",            TESTVFS_UNLOCK_MASK },
1187         { "xLock",              TESTVFS_LOCK_MASK },
1188         { "xCheckReservedLock", TESTVFS_CKLOCK_MASK },
1189         { "xFileControl",       TESTVFS_FCNTL_MASK },
1190       };
1191       Tcl_Obj **apElem = 0;
1192       int nElem = 0;
1193       int mask = 0;
1194       if( objc!=3 ){
1195         Tcl_WrongNumArgs(interp, 2, objv, "LIST");
1196         return TCL_ERROR;
1197       }
1198       if( Tcl_ListObjGetElements(interp, objv[2], &nElem, &apElem) ){
1199         return TCL_ERROR;
1200       }
1201       Tcl_ResetResult(interp);
1202       for(i=0; i<nElem; i++){
1203         int iMethod;
1204         char *zElem = Tcl_GetString(apElem[i]);
1205         for(iMethod=0; iMethod<ArraySize(vfsmethod); iMethod++){
1206           if( strcmp(zElem, vfsmethod[iMethod].zName)==0 ){
1207             mask |= vfsmethod[iMethod].mask;
1208             break;
1209           }
1210         }
1211         if( iMethod==ArraySize(vfsmethod) ){
1212           Tcl_AppendResult(interp, "unknown method: ", zElem, 0);
1213           return TCL_ERROR;
1214         }
1215       }
1216       p->mask = mask;
1217       break;
1218     }
1219 
1220     /*
1221     **  TESTVFS script ?SCRIPT?
1222     **
1223     **  Query or set the script to be run when filtered VFS events
1224     **  occur.
1225     */
1226     case CMD_SCRIPT: {
1227       if( objc==3 ){
1228         int nByte;
1229         if( p->pScript ){
1230           Tcl_DecrRefCount(p->pScript);
1231           p->pScript = 0;
1232         }
1233         Tcl_GetStringFromObj(objv[2], &nByte);
1234         if( nByte>0 ){
1235           p->pScript = Tcl_DuplicateObj(objv[2]);
1236           Tcl_IncrRefCount(p->pScript);
1237         }
1238       }else if( objc!=2 ){
1239         Tcl_WrongNumArgs(interp, 2, objv, "?SCRIPT?");
1240         return TCL_ERROR;
1241       }
1242 
1243       Tcl_ResetResult(interp);
1244       if( p->pScript ) Tcl_SetObjResult(interp, p->pScript);
1245 
1246       break;
1247     }
1248 
1249     /*
1250     ** TESTVFS ioerr ?IFAIL PERSIST?
1251     **
1252     **   Where IFAIL is an integer and PERSIST is boolean.
1253     */
1254     case CMD_CANTOPENERR:
1255     case CMD_IOERR:
1256     case CMD_FULLERR: {
1257       TestFaultInject *pTest = 0;
1258       int iRet;
1259 
1260       switch( aSubcmd[i].eCmd ){
1261         case CMD_IOERR: pTest = &p->ioerr_err; break;
1262         case CMD_FULLERR: pTest = &p->full_err; break;
1263         case CMD_CANTOPENERR: pTest = &p->cantopen_err; break;
1264         default: assert(0);
1265       }
1266       iRet = pTest->nFail;
1267       pTest->nFail = 0;
1268       pTest->eFault = 0;
1269       pTest->iCnt = 0;
1270 
1271       if( objc==4 ){
1272         int iCnt, iPersist;
1273         if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &iCnt)
1274          || TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[3], &iPersist)
1275         ){
1276           return TCL_ERROR;
1277         }
1278         pTest->eFault = iPersist?FAULT_INJECT_PERSISTENT:FAULT_INJECT_TRANSIENT;
1279         pTest->iCnt = iCnt;
1280       }else if( objc!=2 ){
1281         Tcl_WrongNumArgs(interp, 2, objv, "?CNT PERSIST?");
1282         return TCL_ERROR;
1283       }
1284       Tcl_SetObjResult(interp, Tcl_NewIntObj(iRet));
1285       break;
1286     }
1287 
1288     case CMD_DELETE: {
1289       Tcl_DeleteCommand(interp, Tcl_GetString(objv[0]));
1290       break;
1291     }
1292 
1293     case CMD_DEVCHAR: {
1294       struct DeviceFlag {
1295         char *zName;
1296         int iValue;
1297       } aFlag[] = {
1298         { "default",               -1 },
1299         { "atomic",                SQLITE_IOCAP_ATOMIC                },
1300         { "atomic512",             SQLITE_IOCAP_ATOMIC512             },
1301         { "atomic1k",              SQLITE_IOCAP_ATOMIC1K              },
1302         { "atomic2k",              SQLITE_IOCAP_ATOMIC2K              },
1303         { "atomic4k",              SQLITE_IOCAP_ATOMIC4K              },
1304         { "atomic8k",              SQLITE_IOCAP_ATOMIC8K              },
1305         { "atomic16k",             SQLITE_IOCAP_ATOMIC16K             },
1306         { "atomic32k",             SQLITE_IOCAP_ATOMIC32K             },
1307         { "atomic64k",             SQLITE_IOCAP_ATOMIC64K             },
1308         { "sequential",            SQLITE_IOCAP_SEQUENTIAL            },
1309         { "safe_append",           SQLITE_IOCAP_SAFE_APPEND           },
1310         { "undeletable_when_open", SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN },
1311         { "powersafe_overwrite",   SQLITE_IOCAP_POWERSAFE_OVERWRITE   },
1312         { "immutable",             SQLITE_IOCAP_IMMUTABLE             },
1313         { 0, 0 }
1314       };
1315       Tcl_Obj *pRet;
1316       int iFlag;
1317 
1318       if( objc>3 ){
1319         Tcl_WrongNumArgs(interp, 2, objv, "?ATTR-LIST?");
1320         return TCL_ERROR;
1321       }
1322       if( objc==3 ){
1323         int j;
1324         int iNew = 0;
1325         Tcl_Obj **flags = 0;
1326         int nFlags = 0;
1327 
1328         if( Tcl_ListObjGetElements(interp, objv[2], &nFlags, &flags) ){
1329           return TCL_ERROR;
1330         }
1331 
1332         for(j=0; j<nFlags; j++){
1333           int idx = 0;
1334           if( Tcl_GetIndexFromObjStruct(interp, flags[j], aFlag,
1335                 sizeof(aFlag[0]), "flag", 0, &idx)
1336           ){
1337             return TCL_ERROR;
1338           }
1339           if( aFlag[idx].iValue<0 && nFlags>1 ){
1340             Tcl_AppendResult(interp, "bad flags: ", Tcl_GetString(objv[2]), 0);
1341             return TCL_ERROR;
1342           }
1343           iNew |= aFlag[idx].iValue;
1344         }
1345 
1346         p->iDevchar = iNew| 0x10000000;
1347       }
1348 
1349       pRet = Tcl_NewObj();
1350       for(iFlag=0; iFlag<sizeof(aFlag)/sizeof(aFlag[0]); iFlag++){
1351         if( p->iDevchar & aFlag[iFlag].iValue ){
1352           Tcl_ListObjAppendElement(
1353               interp, pRet, Tcl_NewStringObj(aFlag[iFlag].zName, -1)
1354           );
1355         }
1356       }
1357       Tcl_SetObjResult(interp, pRet);
1358 
1359       break;
1360     }
1361 
1362     case CMD_SECTORSIZE: {
1363       if( objc>3 ){
1364         Tcl_WrongNumArgs(interp, 2, objv, "?VALUE?");
1365         return TCL_ERROR;
1366       }
1367       if( objc==3 ){
1368         int iNew = 0;
1369         if( Tcl_GetIntFromObj(interp, objv[2], &iNew) ){
1370           return TCL_ERROR;
1371         }
1372         p->iSectorsize = iNew;
1373       }
1374       Tcl_SetObjResult(interp, Tcl_NewIntObj(p->iSectorsize));
1375       break;
1376     }
1377   }
1378 
1379   return TCL_OK;
1380 }
1381 
1382 static void SQLITE_TCLAPI testvfs_obj_del(ClientData cd){
1383   Testvfs *p = (Testvfs *)cd;
1384   if( p->pScript ) Tcl_DecrRefCount(p->pScript);
1385   sqlite3_vfs_unregister(p->pVfs);
1386   ckfree((char *)p->pVfs);
1387   ckfree((char *)p);
1388 }
1389 
1390 /*
1391 ** Usage:  testvfs VFSNAME ?SWITCHES?
1392 **
1393 ** Switches are:
1394 **
1395 **   -noshm   BOOLEAN             (True to omit shm methods. Default false)
1396 **   -default BOOLEAN             (True to make the vfs default. Default false)
1397 **
1398 ** This command creates two things when it is invoked: an SQLite VFS, and
1399 ** a Tcl command. Both are named VFSNAME. The VFS is installed. It is not
1400 ** installed as the default VFS.
1401 **
1402 ** The VFS passes all file I/O calls through to the underlying VFS.
1403 **
1404 ** Whenever the xShmMap method of the VFS
1405 ** is invoked, the SCRIPT is executed as follows:
1406 **
1407 **   SCRIPT xShmMap    FILENAME ID
1408 **
1409 ** The value returned by the invocation of SCRIPT above is interpreted as
1410 ** an SQLite error code and returned to SQLite. Either a symbolic
1411 ** "SQLITE_OK" or numeric "0" value may be returned.
1412 **
1413 ** The contents of the shared-memory buffer associated with a given file
1414 ** may be read and set using the following command:
1415 **
1416 **   VFSNAME shm FILENAME ?NEWVALUE?
1417 **
1418 ** When the xShmLock method is invoked by SQLite, the following script is
1419 ** run:
1420 **
1421 **   SCRIPT xShmLock    FILENAME ID LOCK
1422 **
1423 ** where LOCK is of the form "OFFSET NBYTE lock/unlock shared/exclusive"
1424 */
1425 static int SQLITE_TCLAPI testvfs_cmd(
1426   ClientData cd,
1427   Tcl_Interp *interp,
1428   int objc,
1429   Tcl_Obj *CONST objv[]
1430 ){
1431   static sqlite3_vfs tvfs_vfs = {
1432     3,                            /* iVersion */
1433     0,                            /* szOsFile */
1434     0,                            /* mxPathname */
1435     0,                            /* pNext */
1436     0,                            /* zName */
1437     0,                            /* pAppData */
1438     tvfsOpen,                     /* xOpen */
1439     tvfsDelete,                   /* xDelete */
1440     tvfsAccess,                   /* xAccess */
1441     tvfsFullPathname,             /* xFullPathname */
1442 #ifndef SQLITE_OMIT_LOAD_EXTENSION
1443     tvfsDlOpen,                   /* xDlOpen */
1444     tvfsDlError,                  /* xDlError */
1445     tvfsDlSym,                    /* xDlSym */
1446     tvfsDlClose,                  /* xDlClose */
1447 #else
1448     0,                            /* xDlOpen */
1449     0,                            /* xDlError */
1450     0,                            /* xDlSym */
1451     0,                            /* xDlClose */
1452 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
1453     tvfsRandomness,               /* xRandomness */
1454     tvfsSleep,                    /* xSleep */
1455     tvfsCurrentTime,              /* xCurrentTime */
1456     0,                            /* xGetLastError */
1457     0,                            /* xCurrentTimeInt64 */
1458     0,                            /* xSetSystemCall */
1459     0,                            /* xGetSystemCall */
1460     0,                            /* xNextSystemCall */
1461   };
1462 
1463   Testvfs *p;                     /* New object */
1464   sqlite3_vfs *pVfs;              /* New VFS */
1465   char *zVfs;
1466   int nByte;                      /* Bytes of space to allocate at p */
1467 
1468   int i;
1469   int isNoshm = 0;                /* True if -noshm is passed */
1470   int isFullshm = 0;              /* True if -fullshm is passed */
1471   int isDefault = 0;              /* True if -default is passed */
1472   int szOsFile = 0;               /* Value passed to -szosfile */
1473   int mxPathname = -1;            /* Value passed to -mxpathname */
1474   int iVersion = 3;               /* Value passed to -iversion */
1475 
1476   if( objc<2 || 0!=(objc%2) ) goto bad_args;
1477   for(i=2; i<objc; i += 2){
1478     int nSwitch;
1479     char *zSwitch;
1480     zSwitch = Tcl_GetStringFromObj(objv[i], &nSwitch);
1481 
1482     if( nSwitch>2 && 0==strncmp("-noshm", zSwitch, nSwitch) ){
1483       if( Tcl_GetBooleanFromObj(interp, objv[i+1], &isNoshm) ){
1484         return TCL_ERROR;
1485       }
1486       if( isNoshm ) isFullshm = 0;
1487     }
1488     else if( nSwitch>2 && 0==strncmp("-default", zSwitch, nSwitch) ){
1489       if( Tcl_GetBooleanFromObj(interp, objv[i+1], &isDefault) ){
1490         return TCL_ERROR;
1491       }
1492     }
1493     else if( nSwitch>2 && 0==strncmp("-szosfile", zSwitch, nSwitch) ){
1494       if( Tcl_GetIntFromObj(interp, objv[i+1], &szOsFile) ){
1495         return TCL_ERROR;
1496       }
1497     }
1498     else if( nSwitch>2 && 0==strncmp("-mxpathname", zSwitch, nSwitch) ){
1499       if( Tcl_GetIntFromObj(interp, objv[i+1], &mxPathname) ){
1500         return TCL_ERROR;
1501       }
1502     }
1503     else if( nSwitch>2 && 0==strncmp("-iversion", zSwitch, nSwitch) ){
1504       if( Tcl_GetIntFromObj(interp, objv[i+1], &iVersion) ){
1505         return TCL_ERROR;
1506       }
1507     }
1508     else if( nSwitch>2 && 0==strncmp("-fullshm", zSwitch, nSwitch) ){
1509       if( Tcl_GetBooleanFromObj(interp, objv[i+1], &isFullshm) ){
1510         return TCL_ERROR;
1511       }
1512       if( isFullshm ) isNoshm = 0;
1513     }
1514     else{
1515       goto bad_args;
1516     }
1517   }
1518 
1519   if( szOsFile<sizeof(TestvfsFile) ){
1520     szOsFile = sizeof(TestvfsFile);
1521   }
1522 
1523   zVfs = Tcl_GetString(objv[1]);
1524   nByte = sizeof(Testvfs) + (int)strlen(zVfs)+1;
1525   p = (Testvfs *)ckalloc(nByte);
1526   memset(p, 0, nByte);
1527   p->iDevchar = -1;
1528   p->iSectorsize = -1;
1529 
1530   /* Create the new object command before querying SQLite for a default VFS
1531   ** to use for 'real' IO operations. This is because creating the new VFS
1532   ** may delete an existing [testvfs] VFS of the same name. If such a VFS
1533   ** is currently the default, the new [testvfs] may end up calling the
1534   ** methods of a deleted object.
1535   */
1536   Tcl_CreateObjCommand(interp, zVfs, testvfs_obj_cmd, p, testvfs_obj_del);
1537   p->pParent = sqlite3_vfs_find(0);
1538   p->interp = interp;
1539 
1540   p->zName = (char *)&p[1];
1541   memcpy(p->zName, zVfs, strlen(zVfs)+1);
1542 
1543   pVfs = (sqlite3_vfs *)ckalloc(sizeof(sqlite3_vfs));
1544   memcpy(pVfs, &tvfs_vfs, sizeof(sqlite3_vfs));
1545   pVfs->pAppData = (void *)p;
1546   pVfs->iVersion = iVersion;
1547   pVfs->zName = p->zName;
1548   pVfs->mxPathname = p->pParent->mxPathname;
1549   if( mxPathname>=0 && mxPathname<pVfs->mxPathname ){
1550     pVfs->mxPathname = mxPathname;
1551   }
1552   pVfs->szOsFile = szOsFile;
1553   p->pVfs = pVfs;
1554   p->isNoshm = isNoshm;
1555   p->isFullshm = isFullshm;
1556   p->mask = TESTVFS_ALL_MASK;
1557 
1558   sqlite3_vfs_register(pVfs, isDefault);
1559 
1560   return TCL_OK;
1561 
1562  bad_args:
1563   Tcl_WrongNumArgs(interp, 1, objv, "VFSNAME ?-noshm BOOL? ?-fullshm BOOL? ?-default BOOL? ?-mxpathname INT? ?-szosfile INT? ?-iversion INT?");
1564   return TCL_ERROR;
1565 }
1566 
1567 extern int getDbPointer(Tcl_Interp *interp, const char *zA, sqlite3 **ppDb);
1568 extern const char *sqlite3ErrName(int);
1569 
1570 /*
1571 ** tclcmd: vfs_shmlock DB DBNAME (shared|exclusive) (lock|unlock) OFFSET N
1572 */
1573 static int SQLITE_TCLAPI test_vfs_shmlock(
1574   void * clientData,
1575   Tcl_Interp *interp,
1576   int objc,
1577   Tcl_Obj *CONST objv[]
1578 ){
1579   const char *azArg1[] = {"shared", "exclusive", 0};
1580   const char *azArg2[] = {"lock", "unlock", 0};
1581   sqlite3 *db = 0;
1582   int rc = SQLITE_OK;
1583   const char *zDbname = 0;
1584   int iArg1 = 0;
1585   int iArg2 = 0;
1586   int iOffset = 0;
1587   int n = 0;
1588   sqlite3_file *pFd;
1589 
1590   if( objc!=7 ){
1591     Tcl_WrongNumArgs(interp, 1, objv,
1592         "DB DBNAME (shared|exclusive) (lock|unlock) OFFSET N"
1593     );
1594     return TCL_ERROR;
1595   }
1596 
1597   zDbname = Tcl_GetString(objv[2]);
1598   if( getDbPointer(interp, Tcl_GetString(objv[1]), &db)
1599    || Tcl_GetIndexFromObj(interp, objv[3], azArg1, "ARG", 0, &iArg1)
1600    || Tcl_GetIndexFromObj(interp, objv[4], azArg2, "ARG", 0, &iArg2)
1601    || Tcl_GetIntFromObj(interp, objv[5], &iOffset)
1602    || Tcl_GetIntFromObj(interp, objv[6], &n)
1603   ){
1604     return TCL_ERROR;
1605   }
1606 
1607   sqlite3_file_control(db, zDbname, SQLITE_FCNTL_FILE_POINTER, (void*)&pFd);
1608   if( pFd==0 ){
1609     return TCL_ERROR;
1610   }
1611   rc = pFd->pMethods->xShmLock(pFd, iOffset, n,
1612       (iArg1==0 ? SQLITE_SHM_SHARED : SQLITE_SHM_EXCLUSIVE)
1613     | (iArg2==0 ? SQLITE_SHM_LOCK : SQLITE_SHM_UNLOCK)
1614   );
1615   Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
1616   return TCL_OK;
1617 }
1618 
1619 
1620 int Sqlitetestvfs_Init(Tcl_Interp *interp){
1621   Tcl_CreateObjCommand(interp, "testvfs", testvfs_cmd, 0, 0);
1622   Tcl_CreateObjCommand(interp, "vfs_shmlock", test_vfs_shmlock, 0, 0);
1623   return TCL_OK;
1624 }
1625 
1626 #endif
1627