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 1.218 2008/11/21 00:24:42 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:

** List of all lockInfo and openCnt objects.  This used to be a hash
** table.  But the number of objects is rarely more than a dozen and
** never exceeds a few thousand.  And lookup is not on a critical
** path oo a simple linked list will suffice.
*/
static struct lockInfo *lockList = 0;
static struct openCnt *openList = 0;

#ifdef SQLITE_TEST
/* simulate multiple hosts by creating unique hostid file paths */
int sqlite3_hostid_num = 0;
#endif


#if IS_VXWORKS
/*
** This hash table is used to bind the canonical file name to a
** unixFile structure and use the hash key (= canonical name)
** instead of the Inode number of the file to find the matching
** lockInfo and openCnt structures. It also helps to make the

#elif defined(USE_PREAD64)
  got = pread64(id->h, pBuf, cnt, offset);
  SimulateIOError( got = -1 );
#else
  newOffset = lseek(id->h, offset, SEEK_SET);
  SimulateIOError( newOffset-- );
  if( newOffset!=offset ){
    if( newOffset == -1 ){
      ((unixFile*)id)->lastErrno = errno;
    }else{
      ((unixFile*)id)->lastErrno = 0;			
    }
    return -1;
  }
  got = read(id->h, pBuf, cnt);

#if defined(USE_PREAD)
  got = pwrite(id->h, pBuf, cnt, offset);
#elif defined(USE_PREAD64)
  got = pwrite64(id->h, pBuf, cnt, offset);
#else
  newOffset = lseek(id->h, offset, SEEK_SET);
  if( newOffset!=offset ){
    if( newOffset == -1 ){
      ((unixFile*)id)->lastErrno = errno;
    }else{
      ((unixFile*)id)->lastErrno = 0;			
    }
    return -1;
  }
  got = write(id->h, pBuf, cnt);

      key[i] = (key[i]&0x80 == 0x80) ? pa=0x20 : pa+0x7E;
    }
  }
#endif
  return SQLITE_OK;
}






/* writes the host id path to path, path should be an pre-allocated buffer
** with enough space for a path */
static int getHostIDPath(char *path, size_t len){
  strlcpy(path, HOSTIDPATH, len);
#ifdef SQLITE_TEST
  if( sqlite3_hostid_num>0 ){
    char suffix[2] = "1";

        }else{
          *(const char **)pArg = ":auto: (not held)";
        }
      } else {
        *(const char **)pArg = NULL;
      }
#else
      *(void**)pArg = NULL;
#endif
      return SQLITE_OK;
    }
    case SQLITE_SET_LOCKPROXYFILE: {
#if SQLITE_ENABLE_LOCKING_STYLE
      unixFile *pFile = (unixFile*)id;
      int rc = SQLITE_OK;

     "/tmp",
     ".",
  };
  static const unsigned char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  unsigned int i, j;
  struct stat buf;
  const char *zDir = ".";

  /* It's odd to simulate an io-error here, but really this is just
  ** using the io-error infrastructure to test that SQLite handles this
  ** function failing. 
  */

  }
  if( isDelete ){
#if IS_VXWORKS
    zPath = zName;
#else
    unlink(zName);
#endif
  }
#if SQLITE_ENABLE_LOCKING_STYLE
  else{
    ((unixFile*)pFile)->oflags = oflags;
  }
#endif
  if( pOutFlags ){
    *pOutFlags = flags;
  }

  assert(fd!=0);
  if( isOpenDirectory ){
    rc = openDirectory(zPath, &dirfd);