SQLite

    /* The cookie mask contains one bit for each database file open.
    ** (Bit 0 is for main, bit 1 is for temp, and so forth.)  Bits are
    ** set for each database that is used.  Generate code to start a
    ** transaction on each used database and to verify the schema cookie
    ** on each used database.
    */
    if( pParse->cookieGoto>0 ){
      yDbMask mask;
      int iDb;
      sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
      for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
        if( (mask & pParse->cookieMask)==0 ) continue;
        sqlite3VdbeUsesBtree(v, iDb);
        sqlite3VdbeAddOp2(v,OP_Transaction, iDb, (mask & pParse->writeMask)!=0);
        if( db->init.busy==0 ){

  if( pToplevel->cookieGoto==0 ){
    Vdbe *v = sqlite3GetVdbe(pToplevel);
    if( v==0 ) return;  /* This only happens if there was a prior error */
    pToplevel->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
  }
  if( iDb>=0 ){
    sqlite3 *db = pToplevel->db;
    yDbMask mask;

    assert( iDb<db->nDb );
    assert( db->aDb[iDb].pBt!=0 || iDb==1 );
    assert( iDb<SQLITE_MAX_ATTACHED+2 );
    mask = ((yDbMask)1)<<iDb;
    if( (pToplevel->cookieMask & mask)==0 ){
      pToplevel->cookieMask |= mask;
      pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
      if( !OMIT_TEMPDB && iDb==1 ){
        sqlite3OpenTempDatabase(pToplevel);
      }
    }

** rollback the whole transaction.  For operations where all constraints
** can be checked before any changes are made to the database, it is never
** necessary to undo a write and the checkpoint should not be set.
*/
void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
  Parse *pToplevel = sqlite3ParseToplevel(pParse);
  sqlite3CodeVerifySchema(pParse, iDb);
  pToplevel->writeMask |= ((yDbMask)1)<<iDb;
  pToplevel->isMultiWrite |= setStatement;
}

/*
** Indicate that the statement currently under construction might write
** more than one entry (example: deleting one row then inserting another,
** inserting multiple rows in a table, or inserting a row and index entries.)

  int rc = SQLITE_NOTFOUND;

  UNUSED_PARAMETER(pNotUsed);
  if( zName==0 ){
    /* If no zName is given, restore all system calls to their default
    ** settings and return NULL
    */
    rc = SQLITE_OK;
    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
      if( aSyscall[i].pDefault ){
        aSyscall[i].pCurrent = aSyscall[i].pDefault;

      }
    }
  }else{
    /* If zName is specified, operate on only the one system call
    ** specified.
    */
    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){

  Trigger *pTrigger;      /* Trigger this program was coded from */
  int orconf;             /* Default ON CONFLICT policy */
  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
};

/*
** The yDbMask datatype for the bitmask of all attached databases.
*/
#if SQLITE_MAX_ATTACHED>30
  typedef sqlite3_uint64 yDbMask;
#else
  typedef unsigned int yDbMask;
#endif

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**

    int iTable;           /* Table cursor number */
    int iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */
  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */
  u8 isMultiWrite;     /* True if statement may affect/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
  int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */

    Tcl_ListObjAppendElement(interp, pList, Tcl_NewStringObj(zSys, -1));
  }

  Tcl_SetObjResult(interp, pList);
  Tcl_DecrRefCount(pList);
  return TCL_OK;
}

static int test_syscall_defaultvfs(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_vfs *pVfs; 

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 2, objv, "");
    return TCL_ERROR;
  }

  pVfs = sqlite3_vfs_find(0);
  Tcl_SetObjResult(interp, Tcl_NewStringObj(pVfs->zName, -1));
  return TCL_OK;
}

static int test_syscall(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  struct SyscallCmd {
    const char *zName;
    Tcl_ObjCmdProc *xCmd;
  } aCmd[] = {
    { "fault",      test_syscall_fault },
    { "install",    test_syscall_install },
    { "uninstall",  test_syscall_uninstall },
    { "reset",      test_syscall_reset },
    { "errno",      test_syscall_errno },
    { "exists",     test_syscall_exists },
    { "list",       test_syscall_list },
    { "defaultvfs", test_syscall_defaultvfs },
    { 0, 0 }
  };
  int iCmd;
  int rc;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ...");

  u8 runOnlyOnce;         /* Automatically expire on reset */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  u8 usesStmtJournal;     /* True if uses a statement journal */
  u8 readOnly;            /* True for read-only statements */
  u8 isPrepareV2;         /* True if prepared with prepare_v2() */
  int nChange;            /* Number of db changes made since last reset */
  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
  int aCounter[3];        /* Counters used by sqlite3_stmt_status() */
  BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
#ifndef SQLITE_OMIT_TRACE
  i64 startTime;          /* Time when query started - used for profiling */
#endif
  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */

**
** The prepared statement has to know in advance which Btree objects
** will be used so that it can acquire mutexes on them all in sorted
** order (via sqlite3VdbeMutexArrayEnter().  Mutexes are acquired
** in order (and released in reverse order) to avoid deadlocks.
*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){
  yDbMask mask;
  assert( i>=0 && i<p->db->nDb && i<sizeof(yDbMask)*8 );
  assert( i<(int)sizeof(p->btreeMask)*8 );
  mask = ((u32)1)<<i;
  if( (p->btreeMask & mask)==0 ){
    p->btreeMask |= mask;
    sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);
  }
}

do_re_test 2.1.2 { lindex $::log 0 } {^os_unix.c:\d+: \(\d+\) unlink\(.*test.db-wal\) - }
do_test 2.1.3 { 
  dbh close
  forcedelete test.db-wal
} {}
  

test_syscall reset
sqlite3_shutdown
test_sqlite3_log 
sqlite3_initialize
finish_test

source $testdir/lock_common.tcl
source $testdir/malloc_common.tcl

if {[llength [info commands test_syscall]]==0} {
  finish_test
  return
} 

if {[test_syscall defaultvfs] != "unix"} {
  finish_test
  return
}
set testprefix syscall

#-------------------------------------------------------------------------
# Tests for the xSetSystemCall method.
#
do_test 1.1.1 {
  list [catch { test_syscall reset open } msg] $msg
} {0 {}}

#
do_test 2.1.1 { test_syscall exists open } 1
do_test 2.1.2 { test_syscall exists nosuchcall } 0

#-------------------------------------------------------------------------
# Tests for the xNextSystemCall method.
#
foreach s {
    open close access getcwd stat fstat ftruncate
    fcntl read pread write pwrite fchmod fallocate

    pread64 pwrite64
} {
  if {[test_syscall exists $s]} {lappend syscall_list $s}
}
do_test 3.1 { lsort [test_syscall list] } [lsort $syscall_list]

#-------------------------------------------------------------------------
# This test verifies that if a call to open() fails and errno is set to
# EINTR, the call is retried. If it succeeds, execution continues as if
# nothing happened. 
#
test_syscall reset

} {
  do_test 8.2.$tn {
    file_control_sizehint_test db main $hint
    file size test.db
  } $size
}

test_syscall reset

finish_test