SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code that is specific to Unix systems.
**
** $Id: os_unix.c,v 1.193 2008/07/10 00:32:42 drh Exp $
*/
#include "sqliteInt.h"
#if SQLITE_OS_UNIX              /* This file is used on unix only */

/*
** If SQLITE_ENABLE_LOCKING_STYLE is defined, then several different 
** locking implementations are provided:

** object keeps a count of the number of unixFile pointing to it.
*/
struct lockInfo {
  struct lockKey key;  /* The lookup key */
  int cnt;             /* Number of SHARED locks held */
  int locktype;        /* One of SHARED_LOCK, RESERVED_LOCK etc. */
  int nRef;            /* Number of pointers to this structure */

};

/*
** An instance of the following structure serves as the key used
** to locate a particular openCnt structure given its inode.  This
** is the same as the lockKey except that the thread ID is omitted.
*/

*/
struct openCnt {
  struct openKey key;   /* The lookup key */
  int nRef;             /* Number of pointers to this structure */
  int nLock;            /* Number of outstanding locks */
  int nPending;         /* Number of pending close() operations */
  int *aPending;        /* Malloced space holding fd's awaiting a close() */

};

/* 
** These hash tables map inodes and file descriptors (really, lockKey and
** openKey structures) into lockInfo and openCnt structures.  Access to 
** these hash tables must be protected by a mutex.


*/
static Hash lockHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0};
static Hash openHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0};

/*
** The locking styles are associated with the different file locking
** capabilities supported by different file systems.  
**
** POSIX locking style fully supports shared and exclusive byte-range locks 
** AFP locking only supports exclusive byte-range locks
** FLOCK only supports a single file-global exclusive lock
** DOTLOCK isn't a true locking style, it refers to the use of a special
**   file named the same as the database file with a '.lock' extension, this
**   can be used on file systems that do not offer any reliable file locking
** NO locking means that no locking will be attempted, this is only used for
**   read-only file systems currently
** UNSUPPORTED means that no locking will be attempted, this is only used for
**   file systems that are known to be unsupported
*/
#define LOCKING_STYLE_POSIX        1
#define LOCKING_STYLE_FLOCK        2
#define LOCKING_STYLE_DOTFILE      3
#define LOCKING_STYLE_NONE         4
#define LOCKING_STYLE_AFP          5

/*
** Helper functions to obtain and relinquish the global mutex.
*/
static void enterMutex(){
  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));

/*
** Release a lockInfo structure previously allocated by findLockInfo().
*/
static void releaseLockInfo(struct lockInfo *pLock){
  if( pLock ){
    pLock->nRef--;
    if( pLock->nRef==0 ){
      sqlite3HashInsert(&lockHash, &pLock->key, sizeof(pLock->key), 0);










      sqlite3_free(pLock);
    }
  }
}

/*
** Release a openCnt structure previously allocated by findLockInfo().
*/
static void releaseOpenCnt(struct openCnt *pOpen){
  if( pOpen ){
    pOpen->nRef--;
    if( pOpen->nRef==0 ){
      sqlite3HashInsert(&openHash, &pOpen->key, sizeof(pOpen->key), 0);










      free(pOpen->aPending);
      sqlite3_free(pOpen);
    }
  }
}

#ifdef SQLITE_ENABLE_LOCKING_STYLE
/*

    testThreadLockingBehavior(fd);
  }
  key1.tid = threadsOverrideEachOthersLocks ? 0 : pthread_self();
#endif
  memset(&key2, 0, sizeof(key2));
  key2.dev = statbuf.st_dev;
  key2.ino = statbuf.st_ino;

  pLock = (struct lockInfo*)sqlite3HashFind(&lockHash, &key1, sizeof(key1));


  if( pLock==0 ){
    struct lockInfo *pOld;
    pLock = sqlite3_malloc( sizeof(*pLock) );
    if( pLock==0 ){
      rc = SQLITE_NOMEM;
      goto exit_findlockinfo;
    }
    pLock->key = key1;
    pLock->nRef = 1;
    pLock->cnt = 0;
    pLock->locktype = 0;
    pOld = sqlite3HashInsert(&lockHash, &pLock->key, sizeof(key1), pLock);
    if( pOld!=0 ){
      assert( pOld==pLock );
      sqlite3_free(pLock);
      rc = SQLITE_NOMEM;
      goto exit_findlockinfo;
    }
  }else{
    pLock->nRef++;
  }
  *ppLock = pLock;
  if( ppOpen!=0 ){

    pOpen = (struct openCnt*)sqlite3HashFind(&openHash, &key2, sizeof(key2));


    if( pOpen==0 ){
      struct openCnt *pOld;
      pOpen = sqlite3_malloc( sizeof(*pOpen) );
      if( pOpen==0 ){
        releaseLockInfo(pLock);
        rc = SQLITE_NOMEM;
        goto exit_findlockinfo;
      }
      pOpen->key = key2;
      pOpen->nRef = 1;
      pOpen->nLock = 0;
      pOpen->nPending = 0;
      pOpen->aPending = 0;
      pOld = sqlite3HashInsert(&openHash, &pOpen->key, sizeof(key2), pOpen);
      if( pOld!=0 ){
        assert( pOld==pOpen );
        sqlite3_free(pOpen);
        releaseLockInfo(pLock);
        rc = SQLITE_NOMEM;
        goto exit_findlockinfo;
      }
    }else{
      pOpen->nRef++;
    }
    *ppOpen = pOpen;
  }

exit_findlockinfo:

      pOpen->nLock--;
      assert( pOpen->nLock>=0 );
      if( pOpen->nLock==0 && pOpen->nPending>0 ){
        int i;
        for(i=0; i<pOpen->nPending; i++){
          close(pOpen->aPending[i]);
        }
        free(pOpen->aPending);
        pOpen->nPending = 0;
        pOpen->aPending = 0;
      }
    }
  }
  leaveMutex();
  if( rc==SQLITE_OK ) pFile->locktype = locktype;

      /* If there are outstanding locks, do not actually close the file just
      ** yet because that would clear those locks.  Instead, add the file
      ** descriptor to pOpen->aPending.  It will be automatically closed when
      ** the last lock is cleared.
      */
      int *aNew;
      struct openCnt *pOpen = pFile->pOpen;
      aNew = realloc( pOpen->aPending, (pOpen->nPending+1)*sizeof(int) );
      if( aNew==0 ){
        /* If a malloc fails, just leak the file descriptor */
      }else{
        pOpen->aPending = aNew;
        pOpen->aPending[pOpen->nPending] = pFile->h;
        pOpen->nPending++;
        pFile->h = -1;

    dotlockUnlock(id, NO_LOCK);
    sqlite3_free(pFile->lockingContext);
  }
  return closeUnixFile(id);
}


#pragma mark No locking

/*
** The nolockLockingContext is void
*/
typedef void nolockLockingContext;

static int nolockCheckReservedLock(sqlite3_file *id, int *pResOut) {

/*
** Close a file.
*/
static int nolockClose(sqlite3_file *id) {
  return closeUnixFile(id);
}

#endif /* SQLITE_ENABLE_LOCKING_STYLE */


/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {

** and assigned here also.
*/
static int fillInUnixFile(
  sqlite3_vfs *pVfs,      /* Pointer to vfs object */
  int h,                  /* Open file descriptor of file being opened */
  int dirfd,              /* Directory file descriptor */
  sqlite3_file *pId,      /* Write to the unixFile structure here */
  const char *zFilename   /* Name of the file being opened */

){




  /* Macro to define the static contents of an sqlite3_io_methods 
  ** structure for a unix backend file. Different locking methods
  ** require different functions for the xClose, xLock, xUnlock and
  ** xCheckReservedLock methods.
  */
  #define IOMETHODS(xClose, xLock, xUnlock, xCheckReservedLock) {    \
    1,                          /* iVersion */                           \

    xCheckReservedLock,         /* xCheckReservedLock */                 \
    unixFileControl,            /* xFileControl */                       \
    unixSectorSize,             /* xSectorSize */                        \
    unixDeviceCharacteristics   /* xDeviceCapabilities */                \
  }
  static sqlite3_io_methods aIoMethod[] = {
    IOMETHODS(unixClose, unixLock, unixUnlock, unixCheckReservedLock) 

#ifdef SQLITE_ENABLE_LOCKING_STYLE
   ,IOMETHODS(flockClose, flockLock, flockUnlock, flockCheckReservedLock)
   ,IOMETHODS(dotlockClose, dotlockLock, dotlockUnlock,dotlockCheckReservedLock)
   ,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock)
   ,IOMETHODS(afpClose, afpLock, afpUnlock, afpCheckReservedLock)
#endif
  };

  int eLockingStyle;
  unixFile *pNew = (unixFile *)pId;
  int rc = SQLITE_OK;





  assert( pNew->pLock==NULL );
  assert( pNew->pOpen==NULL );

  OSTRACE3("OPEN    %-3d %s\n", h, zFilename);    
  pNew->h = h;
  pNew->dirfd = dirfd;
  SET_THREADID(pNew);

  assert(LOCKING_STYLE_POSIX==1);
  assert(LOCKING_STYLE_FLOCK==2);
  assert(LOCKING_STYLE_DOTFILE==3);
  assert(LOCKING_STYLE_NONE==4);
  assert(LOCKING_STYLE_AFP==5);
  eLockingStyle = detectLockingStyle(pVfs, zFilename, h);


  switch( eLockingStyle ){

    case LOCKING_STYLE_POSIX: {
      enterMutex();
      rc = findLockInfo(h, &pNew->pLock, &pNew->pOpen);
      leaveMutex();

  int flags,
  int *pOutFlags
){
  int fd = 0;                    /* File descriptor returned by open() */
  int dirfd = -1;                /* Directory file descriptor */
  int oflags = 0;                /* Flags to pass to open() */
  int eType = flags&0xFFFFFF00;  /* Type of file to open */


  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
  int isCreate     = (flags & SQLITE_OPEN_CREATE);
  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);

    }
  }

#ifdef FD_CLOEXEC
  fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif


  return fillInUnixFile(pVfs, fd, dirfd, pFile, zPath);
}

/*
** Delete the file at zPath. If the dirSync argument is true, fsync()
** the directory after deleting the file.
*/
static int unixDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.315 2008/07/12 14:52:20 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

/*

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[2], &col) ) return TCL_ERROR;

  Tcl_SetObjResult(interp, Tcl_NewIntObj(xFunc(pStmt, col)));
  return TCL_OK;
}

#ifndef SQLITE_OMIT_DISKIO
#if 0
/*
** Usage:  sqlite3OsOpenReadWrite <filename>
*/
static int test_sqlite3OsOpenReadWrite(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_file *pFile;
  int rc;
  int dummy;
  char zBuf[100];

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename", 0);
    return TCL_ERROR;
  }

  rc = sqlite3OsOpenReadWrite(Tcl_GetString(objv[1]), &pFile, &dummy);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  sqlite3TestMakePointerStr(interp, zBuf, pFile);
  Tcl_SetResult(interp, zBuf, 0);
  return TCL_ERROR;
}

/*
** Usage:  sqlite3OsClose <file handle>
*/
static int test_sqlite3OsClose(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_file *pFile;
  int rc;

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filehandle", 0);
    return TCL_ERROR;
  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }
  rc = sqlite3OsClose(&pFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite3OsLock <file handle> <locktype>
*/
static int test_sqlite3OsLock(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_file * pFile;
  int rc;

  if( objc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
        Tcl_GetString(objv[0]), 
        " filehandle (SHARED|RESERVED|PENDING|EXCLUSIVE)", 0);
    return TCL_ERROR;
  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }

  if( 0==strcmp("SHARED", Tcl_GetString(objv[2])) ){
    rc = sqlite3OsLock(pFile, SHARED_LOCK);
  }
  else if( 0==strcmp("RESERVED", Tcl_GetString(objv[2])) ){
    rc = sqlite3OsLock(pFile, RESERVED_LOCK);
  }
  else if( 0==strcmp("PENDING", Tcl_GetString(objv[2])) ){
    rc = sqlite3OsLock(pFile, PENDING_LOCK);
  }
  else if( 0==strcmp("EXCLUSIVE", Tcl_GetString(objv[2])) ){
    rc = sqlite3OsLock(pFile, EXCLUSIVE_LOCK);
  }else{
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
        Tcl_GetString(objv[0]), 
        " filehandle (SHARED|RESERVED|PENDING|EXCLUSIVE)", 0);
    return TCL_ERROR;
  }

  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite3OsUnlock <file handle>
*/
static int test_sqlite3OsUnlock(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_file * pFile;
  int rc;

  if( objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filehandle", 0);
    return TCL_ERROR;
  }

  if( getFilePointer(interp, Tcl_GetString(objv[1]), &pFile) ){
    return TCL_ERROR;
  }
  rc = sqlite3OsUnlock(pFile, NO_LOCK);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite3OsTempFileName
*/
static int test_sqlite3OsTempFileName(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  char zFile[SQLITE_TEMPNAME_SIZE];
  int rc;

  rc = sqlite3OsTempFileName(zFile);
  if( rc!=SQLITE_OK ){
    Tcl_SetResult(interp, (char *)t1ErrorName(rc), TCL_STATIC);
    return TCL_ERROR;
  }
  Tcl_AppendResult(interp, zFile, 0);
  return TCL_OK;
}
#endif
#endif

/*
** Usage:  sqlite_set_magic  DB  MAGIC-NUMBER
**
** Set the db->magic value.  This is used to test error recovery logic.
*/
static int sqlite_set_magic(
  void * clientData,

     { "vfs_initfail_test",          vfs_initfail_test,   0   },
     { "vfs_unregister_all",         vfs_unregister_all,  0   },
     { "vfs_reregister_all",         vfs_reregister_all,  0   },
     { "file_control_test",          file_control_test,   0   },
     { "sqlite3_vfs_list",           vfs_list,     0   },

     /* Functions from os.h */
#ifndef SQLITE_OMIT_DISKIO
#if 0
     { "sqlite3OsOpenReadWrite",test_sqlite3OsOpenReadWrite, 0 },
     { "sqlite3OsClose",        test_sqlite3OsClose, 0 },
     { "sqlite3OsLock",         test_sqlite3OsLock, 0 },
     { "sqlite3OsTempFileName", test_sqlite3OsTempFileName, 0 },
   
     /* Custom test interfaces */
     { "sqlite3OsUnlock",         test_sqlite3OsUnlock, 0    },
#endif
#endif
#ifndef SQLITE_OMIT_UTF16
     { "add_test_collate",        test_collate, 0            },
     { "add_test_collate_needed", test_collate_needed, 0     },
     { "add_test_function",       test_function, 0           },
#endif
     { "sqlite3_test_errstr",     test_errstr, 0             },
     { "tcl_variable_type",       tcl_variable_type, 0       },