1/*
2** 2004 May 22
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 code that modified the OS layer in order to simulate
14** the effect on the database file of an OS crash or power failure.  This
15** is used to test the ability of SQLite to recover from those situations.
16*/
17#if SQLITE_TEST          /* This file is used for testing only */
18#include "sqliteInt.h"
19#include "tcl.h"
20
21#ifndef SQLITE_OMIT_DISKIO  /* This file is a no-op if disk I/O is disabled */
22
23/* #define TRACE_CRASHTEST */
24
25typedef struct CrashFile CrashFile;
26typedef struct CrashGlobal CrashGlobal;
27typedef struct WriteBuffer WriteBuffer;
28
29/*
30** Method:
31**
32**   This layer is implemented as a wrapper around the "real"
33**   sqlite3_file object for the host system. Each time data is
34**   written to the file object, instead of being written to the
35**   underlying file, the write operation is stored in an in-memory
36**   structure (type WriteBuffer). This structure is placed at the
37**   end of a global ordered list (the write-list).
38**
39**   When data is read from a file object, the requested region is
40**   first retrieved from the real file. The write-list is then
41**   traversed and data copied from any overlapping WriteBuffer
42**   structures to the output buffer. i.e. a read() operation following
43**   one or more write() operations works as expected, even if no
44**   data has actually been written out to the real file.
45**
46**   When a fsync() operation is performed, an operating system crash
47**   may be simulated, in which case exit(-1) is called (the call to
48**   xSync() never returns). Whether or not a crash is simulated,
49**   the data associated with a subset of the WriteBuffer structures
50**   stored in the write-list is written to the real underlying files
51**   and the entries removed from the write-list. If a crash is simulated,
52**   a subset of the buffers may be corrupted before the data is written.
53**
54**   The exact subset of the write-list written and/or corrupted is
55**   determined by the simulated device characteristics and sector-size.
56**
57** "Normal" mode:
58**
59**   Normal mode is used when the simulated device has none of the
60**   SQLITE_IOCAP_XXX flags set.
61**
62**   In normal mode, if the fsync() is not a simulated crash, the
63**   write-list is traversed from beginning to end. Each WriteBuffer
64**   structure associated with the file handle used to call xSync()
65**   is written to the real file and removed from the write-list.
66**
67**   If a crash is simulated, one of the following takes place for
68**   each WriteBuffer in the write-list, regardless of which
69**   file-handle it is associated with:
70**
71**     1. The buffer is correctly written to the file, just as if
72**        a crash were not being simulated.
73**
74**     2. Nothing is done.
75**
76**     3. Garbage data is written to all sectors of the file that
77**        overlap the region specified by the WriteBuffer. Or garbage
78**        data is written to some contiguous section within the
79**        overlapped sectors.
80**
81** Device Characteristic flag handling:
82**
83**   If the IOCAP_ATOMIC flag is set, then option (3) above is
84**   never selected.
85**
86**   If the IOCAP_ATOMIC512 flag is set, and the WriteBuffer represents
87**   an aligned write() of an integer number of 512 byte regions, then
88**   option (3) above is never selected. Instead, each 512 byte region
89**   is either correctly written or left completely untouched. Similar
90**   logic governs the behaviour if any of the other ATOMICXXX flags
91**   is set.
92**
93**   If either the IOCAP_SAFEAPPEND or IOCAP_SEQUENTIAL flags are set
94**   and a crash is being simulated, then an entry of the write-list is
95**   selected at random. Everything in the list after the selected entry
96**   is discarded before processing begins.
97**
98**   If IOCAP_SEQUENTIAL is set and a crash is being simulated, option
99**   (1) is selected for all write-list entries except the last. If a
100**   crash is not being simulated, then all entries in the write-list
101**   that occur before at least one write() on the file-handle specified
102**   as part of the xSync() are written to their associated real files.
103**
104**   If IOCAP_SAFEAPPEND is set and the first byte written by the write()
105**   operation is one byte past the current end of the file, then option
106**   (1) is always selected.
107*/
108
109/*
110** Each write operation in the write-list is represented by an instance
111** of the following structure.
112**
113** If zBuf is 0, then this structure represents a call to xTruncate(),
114** not xWrite(). In that case, iOffset is the size that the file is
115** truncated to.
116*/
117struct WriteBuffer {
118  i64 iOffset;                 /* Byte offset of the start of this write() */
119  int nBuf;                    /* Number of bytes written */
120  u8 *zBuf;                    /* Pointer to copy of written data */
121  CrashFile *pFile;            /* File this write() applies to */
122
123  WriteBuffer *pNext;          /* Next in CrashGlobal.pWriteList */
124};
125
126struct CrashFile {
127  const sqlite3_io_methods *pMethod;   /* Must be first */
128  sqlite3_file *pRealFile;             /* Underlying "real" file handle */
129  char *zName;
130  int flags;                           /* Flags the file was opened with */
131
132  /* Cache of the entire file. This is used to speed up OsRead() and
133  ** OsFileSize() calls. Although both could be done by traversing the
134  ** write-list, in practice this is impractically slow.
135  */
136  int iSize;                           /* Size of file in bytes */
137  int nData;                           /* Size of buffer allocated at zData */
138  u8 *zData;                           /* Buffer containing file contents */
139};
140
141struct CrashGlobal {
142  WriteBuffer *pWriteList;     /* Head of write-list */
143  WriteBuffer *pWriteListEnd;  /* End of write-list */
144
145  int iSectorSize;             /* Value of simulated sector size */
146  int iDeviceCharacteristics;  /* Value of simulated device characteristics */
147
148  int iCrash;                  /* Crash on the iCrash'th call to xSync() */
149  char zCrashFile[500];        /* Crash during an xSync() on this file */
150};
151
152static CrashGlobal g = {0, 0, SQLITE_DEFAULT_SECTOR_SIZE, 0, 0};
153
154/*
155** Set this global variable to 1 to enable crash testing.
156*/
157static int sqlite3CrashTestEnable = 0;
158
159static void *crash_malloc(int nByte){
160  return (void *)Tcl_Alloc((size_t)nByte);
161}
162static void crash_free(void *p){
163  Tcl_Free(p);
164}
165static void *crash_realloc(void *p, int n){
166  return (void *)Tcl_Realloc(p, (size_t)n);
167}
168
169/*
170** Wrapper around the sqlite3OsWrite() function that avoids writing to the
171** 512 byte block begining at offset PENDING_BYTE.
172*/
173static int writeDbFile(CrashFile *p, u8 *z, i64 iAmt, i64 iOff){
174  int rc = SQLITE_OK;
175  int iSkip = 0;
176  if( iOff==PENDING_BYTE && (p->flags&SQLITE_OPEN_MAIN_DB) ){
177    iSkip = 512;
178  }
179  if( (iAmt-iSkip)>0 ){
180    rc = sqlite3OsWrite(p->pRealFile, &z[iSkip], iAmt-iSkip, iOff+iSkip);
181  }
182  return rc;
183}
184
185/*
186** Flush the write-list as if xSync() had been called on file handle
187** pFile. If isCrash is true, simulate a crash.
188*/
189static int writeListSync(CrashFile *pFile, int isCrash){
190  int rc = SQLITE_OK;
191  int iDc = g.iDeviceCharacteristics;
192
193  WriteBuffer *pWrite;
194  WriteBuffer **ppPtr;
195
196  /* If this is not a crash simulation, set pFinal to point to the
197  ** last element of the write-list that is associated with file handle
198  ** pFile.
199  **
200  ** If this is a crash simulation, set pFinal to an arbitrarily selected
201  ** element of the write-list.
202  */
203  WriteBuffer *pFinal = 0;
204  if( !isCrash ){
205    for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext){
206      if( pWrite->pFile==pFile ){
207        pFinal = pWrite;
208      }
209    }
210  }else if( iDc&(SQLITE_IOCAP_SEQUENTIAL|SQLITE_IOCAP_SAFE_APPEND) ){
211    int nWrite = 0;
212    int iFinal;
213    for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext) nWrite++;
214    sqlite3_randomness(sizeof(int), &iFinal);
215    iFinal = ((iFinal<0)?-1*iFinal:iFinal)%nWrite;
216    for(pWrite=g.pWriteList; iFinal>0; pWrite=pWrite->pNext) iFinal--;
217    pFinal = pWrite;
218  }
219
220#ifdef TRACE_CRASHTEST
221  printf("Sync %s (is %s crash)\n", pFile->zName, (isCrash?"a":"not a"));
222#endif
223
224  ppPtr = &g.pWriteList;
225  for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){
226    sqlite3_file *pRealFile = pWrite->pFile->pRealFile;
227
228    /* (eAction==1)      -> write block out normally,
229    ** (eAction==2)      -> do nothing,
230    ** (eAction==3)      -> trash sectors.
231    */
232    int eAction = 0;
233    if( !isCrash ){
234      eAction = 2;
235      if( (pWrite->pFile==pFile || iDc&SQLITE_IOCAP_SEQUENTIAL) ){
236        eAction = 1;
237      }
238    }else{
239      char random;
240      sqlite3_randomness(1, &random);
241
242      /* Do not select option 3 (sector trashing) if the IOCAP_ATOMIC flag
243      ** is set or this is an OsTruncate(), not an Oswrite().
244      */
245      if( (iDc&SQLITE_IOCAP_ATOMIC) || (pWrite->zBuf==0) ){
246        random &= 0x01;
247      }
248
249      /* If IOCAP_SEQUENTIAL is set and this is not the final entry
250      ** in the truncated write-list, always select option 1 (write
251      ** out correctly).
252      */
253      if( (iDc&SQLITE_IOCAP_SEQUENTIAL && pWrite!=pFinal) ){
254        random = 0;
255      }
256
257      /* If IOCAP_SAFE_APPEND is set and this OsWrite() operation is
258      ** an append (first byte of the written region is 1 byte past the
259      ** current EOF), always select option 1 (write out correctly).
260      */
261      if( iDc&SQLITE_IOCAP_SAFE_APPEND && pWrite->zBuf ){
262        i64 iSize;
263        sqlite3OsFileSize(pRealFile, &iSize);
264        if( iSize==pWrite->iOffset ){
265          random = 0;
266        }
267      }
268
269      if( (random&0x06)==0x06 ){
270        eAction = 3;
271      }else{
272        eAction = ((random&0x01)?2:1);
273      }
274    }
275
276    switch( eAction ){
277      case 1: {               /* Write out correctly */
278        if( pWrite->zBuf ){
279          rc = writeDbFile(
280              pWrite->pFile, pWrite->zBuf, pWrite->nBuf, pWrite->iOffset
281          );
282        }else{
283          rc = sqlite3OsTruncate(pRealFile, pWrite->iOffset);
284        }
285        *ppPtr = pWrite->pNext;
286#ifdef TRACE_CRASHTEST
287        if( isCrash ){
288          printf("Writing %d bytes @ %d (%s)\n",
289            pWrite->nBuf, (int)pWrite->iOffset, pWrite->pFile->zName
290          );
291        }
292#endif
293        crash_free(pWrite);
294        break;
295      }
296      case 2: {               /* Do nothing */
297        ppPtr = &pWrite->pNext;
298#ifdef TRACE_CRASHTEST
299        if( isCrash ){
300          printf("Omiting %d bytes @ %d (%s)\n",
301            pWrite->nBuf, (int)pWrite->iOffset, pWrite->pFile->zName
302          );
303        }
304#endif
305        break;
306      }
307      case 3: {               /* Trash sectors */
308        u8 *zGarbage;
309        int iFirst = (pWrite->iOffset/g.iSectorSize);
310        int iLast = (pWrite->iOffset+pWrite->nBuf-1)/g.iSectorSize;
311
312        assert(pWrite->zBuf);
313
314#ifdef TRACE_CRASHTEST
315        printf("Trashing %d sectors @ sector %d (%s)\n",
316            1+iLast-iFirst, iFirst, pWrite->pFile->zName
317        );
318#endif
319
320        zGarbage = crash_malloc(g.iSectorSize);
321        if( zGarbage ){
322          sqlite3_int64 i;
323          for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
324            sqlite3_randomness(g.iSectorSize, zGarbage);
325            rc = writeDbFile(
326              pWrite->pFile, zGarbage, g.iSectorSize, i*g.iSectorSize
327            );
328          }
329          crash_free(zGarbage);
330        }else{
331          rc = SQLITE_NOMEM;
332        }
333
334        ppPtr = &pWrite->pNext;
335        break;
336      }
337
338      default:
339        assert(!"Cannot happen");
340    }
341
342    if( pWrite==pFinal ) break;
343  }
344
345  if( rc==SQLITE_OK && isCrash ){
346    exit(-1);
347  }
348
349  for(pWrite=g.pWriteList; pWrite && pWrite->pNext; pWrite=pWrite->pNext);
350  g.pWriteListEnd = pWrite;
351
352  return rc;
353}
354
355/*
356** Add an entry to the end of the write-list.
357*/
358static int writeListAppend(
359  sqlite3_file *pFile,
360  sqlite3_int64 iOffset,
361  const u8 *zBuf,
362  int nBuf
363){
364  WriteBuffer *pNew;
365
366  assert((zBuf && nBuf) || (!nBuf && !zBuf));
367
368  pNew = (WriteBuffer *)crash_malloc(sizeof(WriteBuffer) + nBuf);
369  if( pNew==0 ){
370    fprintf(stderr, "out of memory in the crash simulator\n");
371  }
372  memset(pNew, 0, sizeof(WriteBuffer)+nBuf);
373  pNew->iOffset = iOffset;
374  pNew->nBuf = nBuf;
375  pNew->pFile = (CrashFile *)pFile;
376  if( zBuf ){
377    pNew->zBuf = (u8 *)&pNew[1];
378    memcpy(pNew->zBuf, zBuf, nBuf);
379  }
380
381  if( g.pWriteList ){
382    assert(g.pWriteListEnd);
383    g.pWriteListEnd->pNext = pNew;
384  }else{
385    g.pWriteList = pNew;
386  }
387  g.pWriteListEnd = pNew;
388
389  return SQLITE_OK;
390}
391
392/*
393** Close a crash-file.
394*/
395static int cfClose(sqlite3_file *pFile){
396  CrashFile *pCrash = (CrashFile *)pFile;
397  writeListSync(pCrash, 0);
398  sqlite3OsClose(pCrash->pRealFile);
399  return SQLITE_OK;
400}
401
402/*
403** Read data from a crash-file.
404*/
405static int cfRead(
406  sqlite3_file *pFile,
407  void *zBuf,
408  int iAmt,
409  sqlite_int64 iOfst
410){
411  CrashFile *pCrash = (CrashFile *)pFile;
412
413  /* Check the file-size to see if this is a short-read */
414  if( pCrash->iSize<(iOfst+iAmt) ){
415    return SQLITE_IOERR_SHORT_READ;
416  }
417
418  memcpy(zBuf, &pCrash->zData[iOfst], iAmt);
419  return SQLITE_OK;
420}
421
422/*
423** Write data to a crash-file.
424*/
425static int cfWrite(
426  sqlite3_file *pFile,
427  const void *zBuf,
428  int iAmt,
429  sqlite_int64 iOfst
430){
431  CrashFile *pCrash = (CrashFile *)pFile;
432  if( iAmt+iOfst>pCrash->iSize ){
433    pCrash->iSize = iAmt+iOfst;
434  }
435  while( pCrash->iSize>pCrash->nData ){
436    u8 *zNew;
437    int nNew = (pCrash->nData*2) + 4096;
438    zNew = crash_realloc(pCrash->zData, nNew);
439    if( !zNew ){
440      return SQLITE_NOMEM;
441    }
442    memset(&zNew[pCrash->nData], 0, nNew-pCrash->nData);
443    pCrash->nData = nNew;
444    pCrash->zData = zNew;
445  }
446  memcpy(&pCrash->zData[iOfst], zBuf, iAmt);
447  return writeListAppend(pFile, iOfst, zBuf, iAmt);
448}
449
450/*
451** Truncate a crash-file.
452*/
453static int cfTruncate(sqlite3_file *pFile, sqlite_int64 size){
454  CrashFile *pCrash = (CrashFile *)pFile;
455  assert(size>=0);
456  if( pCrash->iSize>size ){
457    pCrash->iSize = size;
458  }
459  return writeListAppend(pFile, size, 0, 0);
460}
461
462/*
463** Sync a crash-file.
464*/
465static int cfSync(sqlite3_file *pFile, int flags){
466  CrashFile *pCrash = (CrashFile *)pFile;
467  int isCrash = 0;
468
469  const char *zName = pCrash->zName;
470  const char *zCrashFile = g.zCrashFile;
471  int nName = strlen(zName);
472  int nCrashFile = strlen(zCrashFile);
473
474  if( nCrashFile>0 && zCrashFile[nCrashFile-1]=='*' ){
475    nCrashFile--;
476    if( nName>nCrashFile ) nName = nCrashFile;
477  }
478
479  if( nName==nCrashFile && 0==memcmp(zName, zCrashFile, nName) ){
480    if( (--g.iCrash)==0 ) isCrash = 1;
481  }
482
483  return writeListSync(pCrash, isCrash);
484}
485
486/*
487** Return the current file-size of the crash-file.
488*/
489static int cfFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
490  CrashFile *pCrash = (CrashFile *)pFile;
491  *pSize = (i64)pCrash->iSize;
492  return SQLITE_OK;
493}
494
495/*
496** Calls related to file-locks are passed on to the real file handle.
497*/
498static int cfLock(sqlite3_file *pFile, int eLock){
499  return sqlite3OsLock(((CrashFile *)pFile)->pRealFile, eLock);
500}
501static int cfUnlock(sqlite3_file *pFile, int eLock){
502  return sqlite3OsUnlock(((CrashFile *)pFile)->pRealFile, eLock);
503}
504static int cfCheckReservedLock(sqlite3_file *pFile, int *pResOut){
505  return sqlite3OsCheckReservedLock(((CrashFile *)pFile)->pRealFile, pResOut);
506}
507static int cfFileControl(sqlite3_file *pFile, int op, void *pArg){
508  return sqlite3OsFileControl(((CrashFile *)pFile)->pRealFile, op, pArg);
509}
510
511/*
512** The xSectorSize() and xDeviceCharacteristics() functions return
513** the global values configured by the [sqlite_crashparams] tcl
514*  interface.
515*/
516static int cfSectorSize(sqlite3_file *pFile){
517  return g.iSectorSize;
518}
519static int cfDeviceCharacteristics(sqlite3_file *pFile){
520  return g.iDeviceCharacteristics;
521}
522
523/*
524** Pass-throughs for WAL support.
525*/
526static int cfShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
527  return sqlite3OsShmLock(((CrashFile*)pFile)->pRealFile, ofst, n, flags);
528}
529static void cfShmBarrier(sqlite3_file *pFile){
530  sqlite3OsShmBarrier(((CrashFile*)pFile)->pRealFile);
531}
532static int cfShmUnmap(sqlite3_file *pFile, int delFlag){
533  return sqlite3OsShmUnmap(((CrashFile*)pFile)->pRealFile, delFlag);
534}
535static int cfShmMap(
536  sqlite3_file *pFile,            /* Handle open on database file */
537  int iRegion,                    /* Region to retrieve */
538  int sz,                         /* Size of regions */
539  int w,                          /* True to extend file if necessary */
540  void volatile **pp              /* OUT: Mapped memory */
541){
542  return sqlite3OsShmMap(((CrashFile*)pFile)->pRealFile, iRegion, sz, w, pp);
543}
544
545static const sqlite3_io_methods CrashFileVtab = {
546  2,                            /* iVersion */
547  cfClose,                      /* xClose */
548  cfRead,                       /* xRead */
549  cfWrite,                      /* xWrite */
550  cfTruncate,                   /* xTruncate */
551  cfSync,                       /* xSync */
552  cfFileSize,                   /* xFileSize */
553  cfLock,                       /* xLock */
554  cfUnlock,                     /* xUnlock */
555  cfCheckReservedLock,          /* xCheckReservedLock */
556  cfFileControl,                /* xFileControl */
557  cfSectorSize,                 /* xSectorSize */
558  cfDeviceCharacteristics,      /* xDeviceCharacteristics */
559  cfShmMap,                     /* xShmMap */
560  cfShmLock,                    /* xShmLock */
561  cfShmBarrier,                 /* xShmBarrier */
562  cfShmUnmap                    /* xShmUnmap */
563};
564
565/*
566** Application data for the crash VFS
567*/
568struct crashAppData {
569  sqlite3_vfs *pOrig;                   /* Wrapped vfs structure */
570};
571
572/*
573** Open a crash-file file handle.
574**
575** The caller will have allocated pVfs->szOsFile bytes of space
576** at pFile. This file uses this space for the CrashFile structure
577** and allocates space for the "real" file structure using
578** sqlite3_malloc(). The assumption here is (pVfs->szOsFile) is
579** equal or greater than sizeof(CrashFile).
580*/
581static int cfOpen(
582  sqlite3_vfs *pCfVfs,
583  const char *zName,
584  sqlite3_file *pFile,
585  int flags,
586  int *pOutFlags
587){
588  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
589  int rc;
590  CrashFile *pWrapper = (CrashFile *)pFile;
591  sqlite3_file *pReal = (sqlite3_file*)&pWrapper[1];
592
593  memset(pWrapper, 0, sizeof(CrashFile));
594  rc = sqlite3OsOpen(pVfs, zName, pReal, flags, pOutFlags);
595
596  if( rc==SQLITE_OK ){
597    i64 iSize;
598    pWrapper->pMethod = &CrashFileVtab;
599    pWrapper->zName = (char *)zName;
600    pWrapper->pRealFile = pReal;
601    rc = sqlite3OsFileSize(pReal, &iSize);
602    pWrapper->iSize = (int)iSize;
603    pWrapper->flags = flags;
604  }
605  if( rc==SQLITE_OK ){
606    pWrapper->nData = (4096 + pWrapper->iSize);
607    pWrapper->zData = crash_malloc(pWrapper->nData);
608    if( pWrapper->zData ){
609      /* os_unix.c contains an assert() that fails if the caller attempts
610      ** to read data from the 512-byte locking region of a file opened
611      ** with the SQLITE_OPEN_MAIN_DB flag. This region of a database file
612      ** never contains valid data anyhow. So avoid doing such a read here.
613      */
614      const int isDb = (flags&SQLITE_OPEN_MAIN_DB);
615      i64 iChunk = pWrapper->iSize;
616      if( iChunk>PENDING_BYTE && isDb ){
617        iChunk = PENDING_BYTE;
618      }
619      memset(pWrapper->zData, 0, pWrapper->nData);
620      rc = sqlite3OsRead(pReal, pWrapper->zData, iChunk, 0);
621      if( SQLITE_OK==rc && pWrapper->iSize>(PENDING_BYTE+512) && isDb ){
622        i64 iOff = PENDING_BYTE+512;
623        iChunk = pWrapper->iSize - iOff;
624        rc = sqlite3OsRead(pReal, &pWrapper->zData[iOff], iChunk, iOff);
625      }
626    }else{
627      rc = SQLITE_NOMEM;
628    }
629  }
630  if( rc!=SQLITE_OK && pWrapper->pMethod ){
631    sqlite3OsClose(pFile);
632  }
633  return rc;
634}
635
636static int cfDelete(sqlite3_vfs *pCfVfs, const char *zPath, int dirSync){
637  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
638  return pVfs->xDelete(pVfs, zPath, dirSync);
639}
640static int cfAccess(
641  sqlite3_vfs *pCfVfs,
642  const char *zPath,
643  int flags,
644  int *pResOut
645){
646  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
647  return pVfs->xAccess(pVfs, zPath, flags, pResOut);
648}
649static int cfFullPathname(
650  sqlite3_vfs *pCfVfs,
651  const char *zPath,
652  int nPathOut,
653  char *zPathOut
654){
655  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
656  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
657}
658static void *cfDlOpen(sqlite3_vfs *pCfVfs, const char *zPath){
659  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
660  return pVfs->xDlOpen(pVfs, zPath);
661}
662static void cfDlError(sqlite3_vfs *pCfVfs, int nByte, char *zErrMsg){
663  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
664  pVfs->xDlError(pVfs, nByte, zErrMsg);
665}
666static void (*cfDlSym(sqlite3_vfs *pCfVfs, void *pH, const char *zSym))(void){
667  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
668  return pVfs->xDlSym(pVfs, pH, zSym);
669}
670static void cfDlClose(sqlite3_vfs *pCfVfs, void *pHandle){
671  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
672  pVfs->xDlClose(pVfs, pHandle);
673}
674static int cfRandomness(sqlite3_vfs *pCfVfs, int nByte, char *zBufOut){
675  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
676  return pVfs->xRandomness(pVfs, nByte, zBufOut);
677}
678static int cfSleep(sqlite3_vfs *pCfVfs, int nMicro){
679  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
680  return pVfs->xSleep(pVfs, nMicro);
681}
682static int cfCurrentTime(sqlite3_vfs *pCfVfs, double *pTimeOut){
683  sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
684  return pVfs->xCurrentTime(pVfs, pTimeOut);
685}
686
687static int processDevSymArgs(
688  Tcl_Interp *interp,
689  int objc,
690  Tcl_Obj *CONST objv[],
691  int *piDeviceChar,
692  int *piSectorSize
693){
694  struct DeviceFlag {
695    char *zName;
696    int iValue;
697  } aFlag[] = {
698    { "atomic",      SQLITE_IOCAP_ATOMIC      },
699    { "atomic512",   SQLITE_IOCAP_ATOMIC512   },
700    { "atomic1k",    SQLITE_IOCAP_ATOMIC1K    },
701    { "atomic2k",    SQLITE_IOCAP_ATOMIC2K    },
702    { "atomic4k",    SQLITE_IOCAP_ATOMIC4K    },
703    { "atomic8k",    SQLITE_IOCAP_ATOMIC8K    },
704    { "atomic16k",   SQLITE_IOCAP_ATOMIC16K   },
705    { "atomic32k",   SQLITE_IOCAP_ATOMIC32K   },
706    { "atomic64k",   SQLITE_IOCAP_ATOMIC64K   },
707    { "sequential",  SQLITE_IOCAP_SEQUENTIAL  },
708    { "safe_append", SQLITE_IOCAP_SAFE_APPEND },
709    { 0, 0 }
710  };
711
712  int i;
713  int iDc = 0;
714  int iSectorSize = 0;
715  int setSectorsize = 0;
716  int setDeviceChar = 0;
717
718  for(i=0; i<objc; i+=2){
719    int nOpt;
720    char *zOpt = Tcl_GetStringFromObj(objv[i], &nOpt);
721
722    if( (nOpt>11 || nOpt<2 || strncmp("-sectorsize", zOpt, nOpt))
723     && (nOpt>16 || nOpt<2 || strncmp("-characteristics", zOpt, nOpt))
724    ){
725      Tcl_AppendResult(interp,
726        "Bad option: \"", zOpt,
727        "\" - must be \"-characteristics\" or \"-sectorsize\"", 0
728      );
729      return TCL_ERROR;
730    }
731    if( i==objc-1 ){
732      Tcl_AppendResult(interp, "Option requires an argument: \"", zOpt, "\"",0);
733      return TCL_ERROR;
734    }
735
736    if( zOpt[1]=='s' ){
737      if( Tcl_GetIntFromObj(interp, objv[i+1], &iSectorSize) ){
738        return TCL_ERROR;
739      }
740      setSectorsize = 1;
741    }else{
742      int j;
743      Tcl_Obj **apObj;
744      int nObj;
745      if( Tcl_ListObjGetElements(interp, objv[i+1], &nObj, &apObj) ){
746        return TCL_ERROR;
747      }
748      for(j=0; j<nObj; j++){
749        int rc;
750        int iChoice;
751        Tcl_Obj *pFlag = Tcl_DuplicateObj(apObj[j]);
752        Tcl_IncrRefCount(pFlag);
753        Tcl_UtfToLower(Tcl_GetString(pFlag));
754
755        rc = Tcl_GetIndexFromObjStruct(
756            interp, pFlag, aFlag, sizeof(aFlag[0]), "no such flag", 0, &iChoice
757        );
758        Tcl_DecrRefCount(pFlag);
759        if( rc ){
760          return TCL_ERROR;
761        }
762
763        iDc |= aFlag[iChoice].iValue;
764      }
765      setDeviceChar = 1;
766    }
767  }
768
769  if( setDeviceChar ){
770    *piDeviceChar = iDc;
771  }
772  if( setSectorsize ){
773    *piSectorSize = iSectorSize;
774  }
775
776  return TCL_OK;
777}
778
779/*
780** tclcmd:   sqlite_crash_enable ENABLE
781**
782** Parameter ENABLE must be a boolean value. If true, then the "crash"
783** vfs is added to the system. If false, it is removed.
784*/
785static int crashEnableCmd(
786  void * clientData,
787  Tcl_Interp *interp,
788  int objc,
789  Tcl_Obj *CONST objv[]
790){
791  int isEnable;
792  static sqlite3_vfs crashVfs = {
793    2,                  /* iVersion */
794    0,                  /* szOsFile */
795    0,                  /* mxPathname */
796    0,                  /* pNext */
797    "crash",            /* zName */
798    0,                  /* pAppData */
799
800    cfOpen,               /* xOpen */
801    cfDelete,             /* xDelete */
802    cfAccess,             /* xAccess */
803    cfFullPathname,       /* xFullPathname */
804    cfDlOpen,             /* xDlOpen */
805    cfDlError,            /* xDlError */
806    cfDlSym,              /* xDlSym */
807    cfDlClose,            /* xDlClose */
808    cfRandomness,         /* xRandomness */
809    cfSleep,              /* xSleep */
810    cfCurrentTime,        /* xCurrentTime */
811    0,                    /* xGetlastError */
812    0,                    /* xCurrentTimeInt64 */
813  };
814
815  if( objc!=2 ){
816    Tcl_WrongNumArgs(interp, 1, objv, "ENABLE");
817    return TCL_ERROR;
818  }
819
820  if( Tcl_GetBooleanFromObj(interp, objv[1], &isEnable) ){
821    return TCL_ERROR;
822  }
823
824  if( (isEnable && crashVfs.pAppData) || (!isEnable && !crashVfs.pAppData) ){
825    return TCL_OK;
826  }
827
828  if( crashVfs.pAppData==0 ){
829    sqlite3_vfs *pOriginalVfs = sqlite3_vfs_find(0);
830    crashVfs.mxPathname = pOriginalVfs->mxPathname;
831    crashVfs.pAppData = (void *)pOriginalVfs;
832    crashVfs.szOsFile = sizeof(CrashFile) + pOriginalVfs->szOsFile;
833    sqlite3_vfs_register(&crashVfs, 0);
834  }else{
835    crashVfs.pAppData = 0;
836    sqlite3_vfs_unregister(&crashVfs);
837  }
838
839  return TCL_OK;
840}
841
842/*
843** tclcmd:   sqlite_crashparams ?OPTIONS? DELAY CRASHFILE
844**
845** This procedure implements a TCL command that enables crash testing
846** in testfixture.  Once enabled, crash testing cannot be disabled.
847**
848** Available options are "-characteristics" and "-sectorsize". Both require
849** an argument. For -sectorsize, this is the simulated sector size in
850** bytes. For -characteristics, the argument must be a list of io-capability
851** flags to simulate. Valid flags are "atomic", "atomic512", "atomic1K",
852** "atomic2K", "atomic4K", "atomic8K", "atomic16K", "atomic32K",
853** "atomic64K", "sequential" and "safe_append".
854**
855** Example:
856**
857**   sqlite_crashparams -sect 1024 -char {atomic sequential} ./test.db 1
858**
859*/
860static int crashParamsObjCmd(
861  void * clientData,
862  Tcl_Interp *interp,
863  int objc,
864  Tcl_Obj *CONST objv[]
865){
866  int iDelay;
867  const char *zCrashFile;
868  int nCrashFile, iDc, iSectorSize;
869
870  iDc = -1;
871  iSectorSize = -1;
872
873  if( objc<3 ){
874    Tcl_WrongNumArgs(interp, 1, objv, "?OPTIONS? DELAY CRASHFILE");
875    goto error;
876  }
877
878  zCrashFile = Tcl_GetStringFromObj(objv[objc-1], &nCrashFile);
879  if( nCrashFile>=sizeof(g.zCrashFile) ){
880    Tcl_AppendResult(interp, "Filename is too long: \"", zCrashFile, "\"", 0);
881    goto error;
882  }
883  if( Tcl_GetIntFromObj(interp, objv[objc-2], &iDelay) ){
884    goto error;
885  }
886
887  if( processDevSymArgs(interp, objc-3, &objv[1], &iDc, &iSectorSize) ){
888    return TCL_ERROR;
889  }
890
891  if( iDc>=0 ){
892    g.iDeviceCharacteristics = iDc;
893  }
894  if( iSectorSize>=0 ){
895    g.iSectorSize = iSectorSize;
896  }
897
898  g.iCrash = iDelay;
899  memcpy(g.zCrashFile, zCrashFile, nCrashFile+1);
900  sqlite3CrashTestEnable = 1;
901  return TCL_OK;
902
903error:
904  return TCL_ERROR;
905}
906
907static int devSymObjCmd(
908  void * clientData,
909  Tcl_Interp *interp,
910  int objc,
911  Tcl_Obj *CONST objv[]
912){
913  void devsym_register(int iDeviceChar, int iSectorSize);
914
915  int iDc = -1;
916  int iSectorSize = -1;
917
918  if( processDevSymArgs(interp, objc-1, &objv[1], &iDc, &iSectorSize) ){
919    return TCL_ERROR;
920  }
921  devsym_register(iDc, iSectorSize);
922
923  return TCL_OK;
924}
925
926/*
927** tclcmd: register_jt_vfs ?-default? PARENT-VFS
928*/
929static int jtObjCmd(
930  void * clientData,
931  Tcl_Interp *interp,
932  int objc,
933  Tcl_Obj *CONST objv[]
934){
935  int jt_register(char *, int);
936  char *zParent = 0;
937
938  if( objc!=2 && objc!=3 ){
939    Tcl_WrongNumArgs(interp, 1, objv, "?-default? PARENT-VFS");
940    return TCL_ERROR;
941  }
942  zParent = Tcl_GetString(objv[1]);
943  if( objc==3 ){
944    if( strcmp(zParent, "-default") ){
945      Tcl_AppendResult(interp,
946          "bad option \"", zParent, "\": must be -default", 0
947      );
948      return TCL_ERROR;
949    }
950    zParent = Tcl_GetString(objv[2]);
951  }
952
953  if( !(*zParent) ){
954    zParent = 0;
955  }
956  if( jt_register(zParent, objc==3) ){
957    Tcl_AppendResult(interp, "Error in jt_register", 0);
958    return TCL_ERROR;
959  }
960
961  return TCL_OK;
962}
963
964/*
965** tclcmd: unregister_jt_vfs
966*/
967static int jtUnregisterObjCmd(
968  void * clientData,
969  Tcl_Interp *interp,
970  int objc,
971  Tcl_Obj *CONST objv[]
972){
973  void jt_unregister(void);
974
975  if( objc!=1 ){
976    Tcl_WrongNumArgs(interp, 1, objv, "");
977    return TCL_ERROR;
978  }
979
980  jt_unregister();
981  return TCL_OK;
982}
983
984#endif /* SQLITE_OMIT_DISKIO */
985
986/*
987** This procedure registers the TCL procedures defined in this file.
988*/
989int Sqlitetest6_Init(Tcl_Interp *interp){
990#ifndef SQLITE_OMIT_DISKIO
991  Tcl_CreateObjCommand(interp, "sqlite3_crash_enable", crashEnableCmd, 0, 0);
992  Tcl_CreateObjCommand(interp, "sqlite3_crashparams", crashParamsObjCmd, 0, 0);
993  Tcl_CreateObjCommand(interp, "sqlite3_simulate_device", devSymObjCmd, 0, 0);
994  Tcl_CreateObjCommand(interp, "register_jt_vfs", jtObjCmd, 0, 0);
995  Tcl_CreateObjCommand(interp, "unregister_jt_vfs", jtUnregisterObjCmd, 0, 0);
996#endif
997  return TCL_OK;
998}
999
1000#endif /* SQLITE_TEST */
1001