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 1.203 2008/09/23 10:23:26 drh Exp $
*/
#include "sqliteInt.h"
#if SQLITE_OS_UNIX              /* This file is used on unix only */

/*
** If SQLITE_ENABLE_LOCKING_STYLE is defined and is non-zero, then several
** alternative locking implementations are provided:
**
**   * POSIX locking (the default),
**   * No locking,
**   * Dot-file locking,
**   * flock() locking,
**   * AFP locking (OSX only).
**
** SQLITE_ENABLE_LOCKING_STYLE only works on a Mac. It is turned on by
** default on a Mac and disabled on all other posix platforms.
*/
#if !defined(SQLITE_ENABLE_LOCKING_STYLE)
#  if defined(__DARWIN__)
#    define SQLITE_ENABLE_LOCKING_STYLE 1
#  else
#    define SQLITE_ENABLE_LOCKING_STYLE 0
#  endif
#endif

/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it.  If the OS lacks
** large file support, these should be no-ops.
**
** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <sys/time.h>
#include <errno.h>

#if SQLITE_ENABLE_LOCKING_STYLE
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/mount.h>
#endif /* SQLITE_ENABLE_LOCKING_STYLE */

/*
** If we are to be thread-safe, include the pthreads header and define

  /* In test mode, increase the size of this structure a bit so that 
  ** it is larger than the struct CrashFile defined in test6.c.
  */
  char aPadding[32];
#endif
  struct openCnt *pOpen;    /* Info about all open fd's on this inode */
  struct lockInfo *pLock;   /* Info about locks on this inode */
#if SQLITE_ENABLE_LOCKING_STYLE
  void *lockingContext;     /* Locking style specific state */
#endif
  int h;                    /* The file descriptor */
  unsigned char locktype;   /* The type of lock held on this fd */
  int dirfd;                /* File descriptor for the directory */
#if SQLITE_THREADSAFE
  pthread_t tid;            /* The thread that "owns" this unixFile */

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

#if SQLITE_ENABLE_LOCKING_STYLE
/*
** Tests a byte-range locking query to see if byte range locks are 
** supported, if not we fall back to dotlockLockingStyle.
*/
static int testLockingStyle(int fd){
  struct flock lockInfo;

** returns LOCKING_STYLE_POSIX.
*/
static int detectLockingStyle(
  sqlite3_vfs *pVfs,
  const char *filePath, 
  int fd
){
#if SQLITE_ENABLE_LOCKING_STYLE
  struct Mapping {
    const char *zFilesystem;
    int eLockingStyle;
  } aMap[] = {
    { "hfs",    LOCKING_STYLE_POSIX },
    { "ufs",    LOCKING_STYLE_POSIX },
    { "afpfs",  LOCKING_STYLE_AFP },

    closeUnixFile(id);
    leaveMutex();
  }
  return SQLITE_OK;
}


#if SQLITE_ENABLE_LOCKING_STYLE
#pragma mark AFP Support

/*
 ** The afpLockingContext structure contains all afp lock specific state
 */
typedef struct afpLockingContext afpLockingContext;
struct afpLockingContext {

    unixFileControl,            /* xFileControl */                       \
    unixSectorSize,             /* xSectorSize */                        \
    unixDeviceCharacteristics   /* xDeviceCapabilities */                \
  }
  static sqlite3_io_methods aIoMethod[] = {
    IOMETHODS(unixClose, unixLock, unixUnlock, unixCheckReservedLock) 
   ,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock)
#if SQLITE_ENABLE_LOCKING_STYLE
   ,IOMETHODS(dotlockClose, dotlockLock, dotlockUnlock,dotlockCheckReservedLock)
   ,IOMETHODS(flockClose, flockLock, flockUnlock, flockCheckReservedLock)
   ,IOMETHODS(afpClose, afpLock, afpUnlock, afpCheckReservedLock)
#endif
  };
  /* The order of the IOMETHODS macros above is important.  It must be the
  ** same order as the LOCKING_STYLE numbers

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

#if SQLITE_ENABLE_LOCKING_STYLE
    case LOCKING_STYLE_AFP: {
      /* AFP locking uses the file path so it needs to be included in
      ** the afpLockingContext.
      */
      afpLockingContext *pCtx;
      pNew->lockingContext = pCtx = sqlite3_malloc( sizeof(*pCtx) );
      if( pCtx==0 ){

    unixRandomness,       /* xRandomness */                 \
    unixSleep,            /* xSleep */                      \
    unixCurrentTime,      /* xCurrentTime */                \
    unixGetLastError      /* xGetLastError */               \
  }

  static sqlite3_vfs unixVfs = UNIXVFS("unix", 0);
#if SQLITE_ENABLE_LOCKING_STYLE
  int i;
  static sqlite3_vfs aVfs[] = {
    UNIXVFS("unix-posix",   LOCKING_STYLE_POSIX), 
    UNIXVFS("unix-afp",     LOCKING_STYLE_AFP), 
    UNIXVFS("unix-flock",   LOCKING_STYLE_FLOCK), 
    UNIXVFS("unix-dotfile", LOCKING_STYLE_DOTFILE), 
    UNIXVFS("unix-none",    LOCKING_STYLE_NONE)