**   *  Definitions of sqlite3_io_methods objects for all locking
**      methods plus "finder" functions for each locking method.
**   *  sqlite3_vfs method implementations.
**   *  Locking primitives for the proxy uber-locking-method. (MacOSX only)
**   *  Definitions of sqlite3_vfs objects for all locking methods
**      plus implementations of sqlite3_os_init() and sqlite3_os_end().
**
** $Id: os_unix.c,v 1.228 2008/12/03 22:48:33 drh Exp $
*/
#include "sqliteInt.h"
#if SQLITE_OS_UNIX              /* This file is used on unix only */

/*
** There are various methods for file locking used for concurrency
** control:
................................................................................
  */
  if( *pSize==1 ) *pSize = 0;


  return SQLITE_OK;
}


/*
** Handler for proxy-locking file-control verbs.  Defined below in the
** proxying locking division.
*/
static int proxyFileControl(sqlite3_file*,int,void*);



/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
................................................................................
      unixEnterMutex();
      rc = findLockInfo(pNew, NULL, &pNew->pOpen);
      unixLeaveMutex();        
    }
  }
#endif

#if SQLITE_ENABLE_LOCKING_STYLE
  else if( pLockingStyle == &dotlockIoMethods ){
    /* Dotfile locking uses the file path so it needs to be included in
    ** the dotlockLockingContext 
    */
    char *zLockFile;
    int nFilename;
    nFilename = strlen(zFilename) + 6;
................................................................................
    if( zLockFile==0 ){
      rc = SQLITE_NOMEM;
    }else{
      sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename);
    }
    pNew->lockingContext = zLockFile;
  }
#endif

#if OS_VXWORKS
  else if( pLockingStyle == &semIoMethods ){
    /* Named semaphore locking uses the file path so it needs to be
    ** included in the semLockingContext
    */
    unixEnterMutex();
................................................................................
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;
  }while( access(zBuf,0)==0 );
  return SQLITE_OK;
}


/*
** Routine to transform a unixFile into a proxy-locking unixFile.
** Implementation in the proxy-lock division, but used by unixOpen()
** if SQLITE_PREFER_PROXY_LOCKING is defined.
*/
static int proxyTransformUnixFile(unixFile*, const char*);



/*
** Open the file zPath.
** 
** Previously, the SQLite OS layer used three functions in place of this
** one:

**   *  Definitions of sqlite3_io_methods objects for all locking
**      methods plus "finder" functions for each locking method.
**   *  sqlite3_vfs method implementations.
**   *  Locking primitives for the proxy uber-locking-method. (MacOSX only)
**   *  Definitions of sqlite3_vfs objects for all locking methods
**      plus implementations of sqlite3_os_init() and sqlite3_os_end().
**
** $Id: os_unix.c,v 1.229 2008/12/04 12:34:16 drh Exp $
*/
#include "sqliteInt.h"
#if SQLITE_OS_UNIX              /* This file is used on unix only */

/*
** There are various methods for file locking used for concurrency
** control:
................................................................................
  */
  if( *pSize==1 ) *pSize = 0;


  return SQLITE_OK;
}

#if SQLITE_ENABLE_LOCKING_MODE && defined(__DARWIN__)
/*
** Handler for proxy-locking file-control verbs.  Defined below in the
** proxying locking division.
*/
static int proxyFileControl(sqlite3_file*,int,void*);
#endif


/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  switch( op ){
................................................................................
      unixEnterMutex();
      rc = findLockInfo(pNew, NULL, &pNew->pOpen);
      unixLeaveMutex();        
    }
  }
#endif


  else if( pLockingStyle == &dotlockIoMethods ){
    /* Dotfile locking uses the file path so it needs to be included in
    ** the dotlockLockingContext 
    */
    char *zLockFile;
    int nFilename;
    nFilename = strlen(zFilename) + 6;
................................................................................
    if( zLockFile==0 ){
      rc = SQLITE_NOMEM;
    }else{
      sqlite3_snprintf(nFilename, zLockFile, "%s" DOTLOCK_SUFFIX, zFilename);
    }
    pNew->lockingContext = zLockFile;
  }


#if OS_VXWORKS
  else if( pLockingStyle == &semIoMethods ){
    /* Named semaphore locking uses the file path so it needs to be
    ** included in the semLockingContext
    */
    unixEnterMutex();
................................................................................
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;
  }while( access(zBuf,0)==0 );
  return SQLITE_OK;
}

#if SQLITE_ENABLE_LOCKING_MODE && defined(__DARWIN__)
/*
** Routine to transform a unixFile into a proxy-locking unixFile.
** Implementation in the proxy-lock division, but used by unixOpen()
** if SQLITE_PREFER_PROXY_LOCKING is defined.
*/
static int proxyTransformUnixFile(unixFile*, const char*);
#endif


/*
** Open the file zPath.
** 
** Previously, the SQLite OS layer used three functions in place of this
** one:

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is database locks.
#
# $Id: lock5.test,v 1.5 2008/11/29 02:20:27 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# This file is only run if using the unix backend compiled with the
# SQLITE_ENABLE_LOCKING_STYLE macro.
db close
................................................................................
  db close
  file exists test.db.lock
} {0}

#####################################################################

file delete -force test.db





do_test lock5-flock.1 {
  sqlite3 db test.db -vfs unix-flock
  execsql {
    CREATE TABLE t1(a, b);
    BEGIN;
    INSERT INTO t1 VALUES(1, 2);

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is database locks.
#
# $Id: lock5.test,v 1.6 2008/12/04 12:34:16 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# This file is only run if using the unix backend compiled with the
# SQLITE_ENABLE_LOCKING_STYLE macro.
db close
................................................................................
  db close
  file exists test.db.lock
} {0}

#####################################################################

file delete -force test.db
if {[catch {sqlite3 db test.db -vfs unix-flock} msg]} {
  finish_test
  return
}

do_test lock5-flock.1 {
  sqlite3 db test.db -vfs unix-flock
  execsql {
    CREATE TABLE t1(a, b);
    BEGIN;
    INSERT INTO t1 VALUES(1, 2);