SQLite

  TestvfsBuffer *pShm;            /* Shared memory buffer */
  u32 excllock;                   /* Mask of exclusive locks */
  u32 sharedlock;                 /* Mask of shared locks */
  TestvfsFile *pNext;             /* Next handle opened on the same file */
};

#define FAULT_INJECT_NONE       0
#define FAULT_INJECT_TRANSIENT  1
#define FAULT_INJECT_PERSISTENT 2

typedef struct TestFaultInject TestFaultInject;
struct TestFaultInject {
  int iCnt;                       /* Remaining calls before fault injection */
  int eFault;                     /* A FAULT_INJECT_* value */
  int nFail;                      /* Number of faults injected */
};

/*
** An instance of this structure is allocated for each VFS created. The
** sqlite3_vfs.pAppData field of the VFS structure registered with SQLite
** is set to point to it.
*/
struct Testvfs {
  char *zName;                    /* Name of this VFS */
  sqlite3_vfs *pParent;           /* The VFS to use for file IO */
  sqlite3_vfs *pVfs;              /* The testvfs registered with SQLite */
  Tcl_Interp *interp;             /* Interpreter to run script in */
  Tcl_Obj *pScript;               /* Script to execute */
  int nScript;                    /* Number of elements in array apScript */
  Tcl_Obj **apScript;             /* Array version of pScript */
  TestvfsBuffer *pBuffer;         /* List of shared buffers */
  int isNoshm;

  int mask;                       /* Mask controlling [script] and [ioerr] */

  TestFaultInject ioerr_err;
  TestFaultInject full_err;
  TestFaultInject cantopen_err;

#if 0
  int iIoerrCnt;
  int ioerr;
  int nIoerrFail;

  int iFullCnt;
  int fullerr;
  int nFullFail;
#endif

  int iDevchar;
  int iSectorsize;
};

/*
** The Testvfs.mask variable is set to a combination of the following.

#define TESTVFS_OPEN_MASK       0x00000100
#define TESTVFS_SYNC_MASK       0x00000200
#define TESTVFS_DELETE_MASK     0x00000400
#define TESTVFS_CLOSE_MASK      0x00000800
#define TESTVFS_WRITE_MASK      0x00001000
#define TESTVFS_TRUNCATE_MASK   0x00002000
#define TESTVFS_ACCESS_MASK     0x00004000
#define TESTVFS_ALL_MASK        0x00007FFF


#define TESTVFS_MAX_PAGES 1024

/*
** A shared-memory buffer. There is one of these objects for each shared
** memory region opened by clients. If two clients open the same file,

      return 1;
    }
  }

  return 0;
}

static int tvfsInjectFault(TestFaultInject *p){
  int ret = 0;
  if( p->eFault ){
    p->iCnt--;
    if( p->iCnt==0 || (p->iCnt<0 && p->eFault==FAULT_INJECT_PERSISTENT ) ){
      ret = 1;
      p->nFail++;
    }
  }
  return ret;
}


static int tvfsInjectIoerr(Testvfs *p){


  return tvfsInjectFault(&p->ioerr_err);



}

static int tvfsInjectFullerr(Testvfs *p){
  return tvfsInjectFault(&p->full_err);
}
static int tvfsInjectCantopenerr(Testvfs *p){
  return tvfsInjectFault(&p->cantopen_err);
}


static void tvfsExecTcl(
  Testvfs *p, 
  const char *zMethod,
  Tcl_Obj *arg1,

    tvfsExecTcl(p, "xOpen", Tcl_NewStringObj(pFd->zFilename, -1), 0, 0);
    if( tvfsResultCode(p, &rc) ){
      if( rc!=SQLITE_OK ) return rc;
    }else{
      pId = Tcl_GetObjResult(p->interp);
    }
  }

  if( (p->mask&TESTVFS_OPEN_MASK) &&  tvfsInjectIoerr(p) ) return SQLITE_IOERR;
  if( tvfsInjectCantopenerr(p) ) return SQLITE_CANTOPEN;
  if( tvfsInjectFullerr(p) ) return SQLITE_FULL;

  if( !pId ){
    pId = Tcl_NewStringObj("anon", -1);
  }
  Tcl_IncrRefCount(pId);
  pFd->pShmId = pId;
  Tcl_ResetResult(p->interp);


  rc = sqlite3OsOpen(PARENTVFS(pVfs), zName, pFd->pReal, flags, pOutFlags);
  if( pFd->pReal->pMethods ){
    sqlite3_io_methods *pMethods;
    pMethods = (sqlite3_io_methods *)ckalloc(sizeof(sqlite3_io_methods));
    memcpy(pMethods, &tvfs_io_methods, sizeof(sqlite3_io_methods));
    if( ((Testvfs *)pVfs->pAppData)->isNoshm ){

*/
static int tvfsAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){
  Testvfs *p = (Testvfs *)pVfs->pAppData;
  if( p->pScript && p->mask&TESTVFS_ACCESS_MASK ){
    int rc;
    char *zArg = 0;
    if( flags==SQLITE_ACCESS_EXISTS ) zArg = "SQLITE_ACCESS_EXISTS";
    if( flags==SQLITE_ACCESS_READWRITE ) zArg = "SQLITE_ACCESS_READWRITE";
    if( flags==SQLITE_ACCESS_READ ) zArg = "SQLITE_ACCESS_READ";
    tvfsExecTcl(p, "xAccess", 
        Tcl_NewStringObj(zPath, -1), Tcl_NewStringObj(zArg, -1), 0
    );
    if( tvfsResultCode(p, &rc) ){
      if( rc!=SQLITE_OK ) return rc;
    }else{
      Tcl_Interp *interp = p->interp;
      if( TCL_OK==Tcl_GetBooleanFromObj(0, Tcl_GetObjResult(interp), pResOut) ){
        return SQLITE_OK;
      }
    }
  }
  return sqlite3OsAccess(PARENTVFS(pVfs), zPath, flags, pResOut);
}

/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (DEVSYM_MAX_PATHNAME+1) bytes.

  int objc,
  Tcl_Obj *CONST objv[]
){
  Testvfs *p = (Testvfs *)cd;

  enum DB_enum { 
    CMD_SHM, CMD_DELETE, CMD_FILTER, CMD_IOERR, CMD_SCRIPT, 
    CMD_DEVCHAR, CMD_SECTORSIZE, CMD_FULLERR, CMD_CANTOPENERR
  };
  struct TestvfsSubcmd {
    char *zName;
    enum DB_enum eCmd;
  } aSubcmd[] = {
    { "shm",         CMD_SHM         },
    { "delete",      CMD_DELETE      },
    { "filter",      CMD_FILTER      },
    { "ioerr",       CMD_IOERR       },
    { "fullerr",     CMD_FULLERR     },
    { "cantopenerr", CMD_CANTOPENERR },
    { "script",      CMD_SCRIPT      },
    { "devchar",     CMD_DEVCHAR     },
    { "sectorsize",  CMD_SECTORSIZE  },
    { 0, 0 }
  };
  int i;
  
  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
    return TCL_ERROR;

        { "xShmMap",     TESTVFS_SHMMAP_MASK },
        { "xSync",       TESTVFS_SYNC_MASK },
        { "xDelete",     TESTVFS_DELETE_MASK },
        { "xWrite",      TESTVFS_WRITE_MASK },
        { "xTruncate",   TESTVFS_TRUNCATE_MASK },
        { "xOpen",       TESTVFS_OPEN_MASK },
        { "xClose",      TESTVFS_CLOSE_MASK },
        { "xAccess",     TESTVFS_ACCESS_MASK },
      };
      Tcl_Obj **apElem = 0;
      int nElem = 0;
      int i;
      int mask = 0;
      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "LIST");

      Tcl_ResetResult(interp);
      if( p->pScript ) Tcl_SetObjResult(interp, p->pScript);

      break;
    }





























    /*
    ** TESTVFS ioerr ?IFAIL PERSIST?
    **
    **   Where IFAIL is an integer and PERSIST is boolean.
    */
    case CMD_CANTOPENERR:
    case CMD_IOERR:
    case CMD_FULLERR: {
      TestFaultInject *pTest;
      int iRet;

      switch( aSubcmd[i].eCmd ){
        case CMD_IOERR: pTest = &p->ioerr_err; break;
        case CMD_FULLERR: pTest = &p->full_err; break;
        case CMD_CANTOPENERR: pTest = &p->cantopen_err; break;
        default: assert(0);
      }
      iRet = pTest->nFail;
      pTest->nFail = 0;
      pTest->eFault = 0;
      pTest->iCnt = 0;

      if( objc==4 ){
        int iCnt, iPersist;
        if( TCL_OK!=Tcl_GetIntFromObj(interp, objv[2], &iCnt)
         || TCL_OK!=Tcl_GetBooleanFromObj(interp, objv[3], &iPersist)
        ){
          return TCL_ERROR;
        }
        pTest->eFault = iPersist?FAULT_INJECT_PERSISTENT:FAULT_INJECT_TRANSIENT;
        pTest->iCnt = iCnt;
      }else if( objc!=2 ){
        Tcl_WrongNumArgs(interp, 2, objv, "?CNT PERSIST?");
        return TCL_ERROR;
      }
      Tcl_SetObjResult(interp, Tcl_NewIntObj(iRet));
      break;
    }

    case CMD_DELETE: {

  -injectinstall   shmerr_injectinstall    \
  -injectstart     {shmerr_injectstart 1}  \
  -injectstop      shmerr_injectstop       \
  -injecterrlist   {{1 {disk I/O error}}}  \
  -injectuninstall shmerr_injectuninstall  \
]

# Transient and persistent CANTOPEN errors:
#
set FAULTSIM(cantopen-transient) [list       \
  -injectinstall   cantopen_injectinstall    \
  -injectstart     {cantopen_injectstart 0}  \
  -injectstop      cantopen_injectstop       \
  -injecterrlist   {{1 {unable to open database file}}}  \
  -injectuninstall cantopen_injectuninstall  \
]
set FAULTSIM(cantopen-persistent) [list      \
  -injectinstall   cantopen_injectinstall    \
  -injectstart     {cantopen_injectstart 1}  \
  -injectstop      cantopen_injectstop       \
  -injecterrlist   {{1 {unable to open database file}}}  \
  -injectuninstall cantopen_injectuninstall  \
]



#--------------------------------------------------------------------------
# Usage do_faultsim_test NAME ?OPTIONS...? 
#
#     -faults           List of fault types to simulate.
#

  catch {db2 close}
  shmfault delete
}
proc shmerr_injectstart {persist iFail} {
  shmfault ioerr $iFail $persist
}
proc shmerr_injectstop {} {
  shmfault ioerr
}

# The following procs are used as [do_one_faultsim_test] callbacks when 
# injecting SQLITE_FULL error faults into test cases.
#
proc fullerr_injectinstall {} {
  testvfs shmfault -default true
}
proc fullerr_injectuninstall {} {
  catch {db  close}
  catch {db2 close}
  shmfault delete
}
proc fullerr_injectstart {iFail} {
  shmfault full $iFail 1
}
proc fullerr_injectstop {} {
  shmfault full
}

# The following procs are used as [do_one_faultsim_test] callbacks when 
# injecting SQLITE_CANTOPEN error faults into test cases.
#
proc cantopen_injectinstall {} {
  testvfs shmfault -default true
}
proc cantopen_injectuninstall {} {
  catch {db  close}
  catch {db2 close}
  shmfault delete
}
proc cantopen_injectstart {persist iFail} {
  shmfault cantopen $iFail $persist
}
proc cantopen_injectstop {} {
  shmfault cantopen
}

# This command is not called directly. It is used by the 
# [faultsim_test_result] command created by [do_faultsim_test] and used
# by -test scripts.
#
proc faultsim_test_result_int {args} {

} {truncate ok}
do_test pager1-11.4 {
  db2 close
  file size test.db-journal
} {0}
breakpoint
do_execsql_test pager1-11.5 { SELECT count(*) FROM zz } {32}
db close
tv delete
  
#-------------------------------------------------------------------------
# Test "PRAGMA page_size"
#
foreach pagesize {
    512   1024   2048 4096 8192 16384 32768 
} {
  faultsim_delete_and_reopen

  do_test pager1-12.$pagesize.1 {
    sqlite3 db2 test.db
    execsql "
      PRAGMA page_size = $pagesize;
      CREATE VIEW v AS SELECT * FROM sqlite_master;
    " db2
    file size test.db
  } $pagesize
  do_test pager1-12.$pagesize.2 {
    sqlite3 db2 test.db
    execsql { 
      SELECT count(*) FROM v;
      PRAGMA main.page_size;
    } db2
  } [list 1 $pagesize]
  do_test pager1-12.$pagesize.3 {
    execsql { 
      SELECT count(*) FROM v;
      PRAGMA main.page_size;
    }
  } [list 1 $pagesize]
  db2 close
}

finish_test

  faultsim_integrity_check

  set res ""
  set rc [catch { set res [db one { PRAGMA aux.integrity_check }] }]
  if {$rc!=0 || $res != "ok"} {error "integrity-check problem:$rc $res"}
}


#-------------------------------------------------------------------------
# Test fault-injection as part of a commit when using 
# journal_mode=TRUNCATE.
#
do_test pagerfault-6-pre1 {
  faultsim_delete_and_reopen
  db func a_string a_string
  execsql {
    CREATE TABLE t1(a UNIQUE, b UNIQUE);
    INSERT INTO t1 VALUES(a_string(200), a_string(300));
  }
  faultsim_save_and_close
} {}

do_faultsim_test pagerfault-6.1 -prep {
  faultsim_restore_and_reopen
  db func a_string a_string
  execsql { PRAGMA journal_mode = TRUNCATE }
} -body {
  execsql { INSERT INTO t1 SELECT a_string(200), a_string(300) FROM t1 }
  execsql { INSERT INTO t1 SELECT a_string(200), a_string(300) FROM t1 }
} -test {
  faultsim_test_result {0 {}}
  faultsim_integrity_check
}

# The unix vfs xAccess() method considers a file zero bytes in size to
# "not exist". This proc overrides that behaviour so that a zero length
# file is considered to exist.
#
proc xAccess {method filename op args} {
  if {$op != "SQLITE_ACCESS_EXISTS"} { return "" }
  return [file exists $filename]
}
do_faultsim_test pagerfault-6.2 -faults cantopen-* -prep {
  shmfault filter xAccess
  shmfault script xAccess

  faultsim_restore_and_reopen
  db func a_string a_string
  execsql { PRAGMA journal_mode = TRUNCATE }
} -body {
  execsql { INSERT INTO t1 SELECT a_string(200), a_string(300) FROM t1 }
  execsql { INSERT INTO t1 SELECT a_string(200), a_string(300) FROM t1 }
} -test {
  faultsim_test_result {0 {}}
  faultsim_integrity_check
}

# The following was an attempt to get a bitvec malloc to fail. Didn't work.