@ -17,13 +17,23 @@
# include "mysys_err.h"
# include <my_sys.h>
# ifdef _WIN32
static int my_win_unlink ( const char * name ) ;
# endif
int my_delete ( const char * name , myf MyFlags )
{
int err ;
DBUG_ENTER ( " my_delete " ) ;
DBUG_PRINT ( " my " , ( " name %s MyFlags %d " , name , MyFlags ) ) ;
if ( ( err = unlink ( name ) ) = = - 1 )
# ifdef _WIN32
err = my_win_unlink ( name ) ;
# else
err = unlink ( name ) ;
# endif
if ( err )
{
my_errno = errno ;
if ( MyFlags & ( MY_FAE + MY_WME ) )
@ -36,90 +46,108 @@ int my_delete(const char *name, myf MyFlags)
DBUG_RETURN ( err ) ;
} /* my_delete */
# if defined(__WIN__)
/**
Delete file which is possibly not closed .
This function is intended to be used exclusively as a temporal solution
for Win NT in case when it is needed to delete a not closed file ( note
that the file must be opened everywhere with FILE_SHARE_DELETE mode ) .
Deleting not - closed files can not be supported on Win 98 | ME ( and because
of that is considered harmful ) .
The function deletes the file with its preliminary renaming . This is
because when not - closed share - delete file is deleted it still lives on
a disk until it will not be closed everwhere . This may conflict with an
attempt to create a new file with the same name . The deleted file is
renamed to < name > . < num > . deleted where < name > - the initial name of the
file , < num > - a hexadecimal number chosen to make the temporal name to
be unique .
# if defined (_WIN32)
/*
Delete file .
@ param the name of the being deleted file
@ param the flags instructing how to react on an error internally in
the function
The function also makes best effort to minimize number of errors ,
where another program ( or thread in the current program ) has the the same file
open .
@ note The per - thread @ c my_errno holds additional info for a caller to
decide how critical the error can be .
We ' re using 2 tricks to prevent the errors .
@ retval
0 ok
@ retval
1 error
1. A usual Win32 ' s DeleteFile ( ) can with ERROR_SHARED_VIOLATION ,
because the file is opened in another application ( often , antivirus or backup )
We avoid the error by using CreateFile ( ) with FILE_FLAG_DELETE_ON_CLOSE , instead
of DeleteFile ( )
2. If file which is deleted ( delete on close ) but has not entirely gone ,
because it is still opened by some app , an attempt to trcreate file with the
same name would result in yet another error . The workaround here is renaming
a file to unique name .
*/
int nt_share_delete ( const char * name , myf MyFlags )
Symbolic link are deleted without renaming . Directories are not deleted .
*/
static int my_win_unlink ( const char * name )
{
char buf [ MAX_PATH + 20 ] ;
ulong cnt ;
DBUG_ENTER ( " nt_share_delete " ) ;
DBUG_PRINT ( " my " , ( " name %s MyFlags %d " , name , MyFlags ) ) ;
for ( cnt = GetTickCount ( ) ; cnt ; cnt - - )
HANDLE handle = INVALID_HANDLE_VALUE ;
DWORD attributes ;
DWORD last_error ;
char unique_filename [ MAX_PATH + 35 ] ;
unsigned long long tsc ; /* time stamp counter, for unique filename*/
DBUG_ENTER ( " my_win_unlink " ) ;
attributes = GetFileAttributes ( name ) ;
if ( attributes = = INVALID_FILE_ATTRIBUTES )
{
errno = 0 ;
sprintf ( buf , " %s.%08X.deleted " , name , cnt ) ;
if ( MoveFile ( name , buf ) )
break ;
if ( ( errno = GetLastError ( ) ) = = ERROR_ALREADY_EXISTS )
continue ;
/* This happened during tests with MERGE tables. */
if ( errno = = ERROR_ACCESS_DENIED )
continue ;
DBUG_PRINT ( " warning " , ( " Failed to rename %s to %s, errno: %d " ,
name , buf , errno ) ) ;
break ;
last_error = GetLastError ( ) ;
DBUG_PRINT ( " error " , ( " GetFileAttributes(%s) failed with %u \n " , name , last_error ) ) ;
goto error ;
}
if ( errno = = ERROR_FILE_NOT_FOUND )
if ( attributes & FILE_ATTRIBUTE_DIRECTORY )
{
my_errno = ENOENT ; / / marking , that ` name ' doesn ' t exist
DBUG_PRINT ( " error " , ( " can't remove %s - it is a directory \n " , name ) ) ;
errno = EINVAL ;
DBUG_RETURN ( - 1 ) ;
}
else if ( errno = = 0 )
if ( attributes & FILE_ATTRIBUTE_REPARSE_POINT )
{
/* Symbolic link. Delete link, the not target */
if ( ! DeleteFile ( name ) )
{
last_error = GetLastError ( ) ;
DBUG_PRINT ( " error " , ( " DeleteFile(%s) failed with %u \n " , name , last_error ) ) ;
goto error ;
}
DBUG_RETURN ( 0 ) ;
}
handle = CreateFile ( name , DELETE , 0 , NULL , OPEN_EXISTING , FILE_FLAG_DELETE_ON_CLOSE , NULL ) ;
if ( handle ! = INVALID_HANDLE_VALUE )
{
if ( DeleteFile ( buf ) )
DBUG_RETURN ( 0 ) ;
/*
The below is more complicated than necessary . For some reason , the
assignment to my_errno clears the error number , which is retrieved
by GetLastError ( ) ( VC2005EE ) . Assigning to errno first , allows to
retrieve the correct value .
We opened file without sharing flags ( exclusive ) , noone else has this file
opened , thus it is save to close handle to remove it . No renaming is
necessary .
*/
errno = GetLastError ( ) ;
if ( errno = = 0 )
my_errno = ENOENT ; / / marking , that ` buf ' doesn ' t exist
else
my_errno = errno ;
CloseHandle ( handle ) ;
DBUG_RETURN ( 0 ) ;
}
/*
Can ' t open file exclusively , hence the file must be already opened by
someone else . Open it for delete ( with all FILE_SHARE flags set ) ,
rename to unique name , close .
*/
handle = CreateFile ( name , DELETE , FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE ,
NULL , OPEN_EXISTING , FILE_FLAG_DELETE_ON_CLOSE , NULL ) ;
if ( handle = = INVALID_HANDLE_VALUE )
{
last_error = GetLastError ( ) ;
DBUG_PRINT ( " error " ,
( " CreateFile(%s) with FILE_FLAG_DELETE_ON_CLOSE failed with %u \n " ,
name , last_error ) ) ;
goto error ;
}
else
my_errno = errno ;
if ( MyFlags & ( MY_FAE + MY_WME ) )
my_error ( EE_DELETE , MYF ( ME_BELL + ME_WAITTANG + ( MyFlags & ME_NOINPUT ) ) ,
name , my_errno ) ;
tsc = __rdtsc ( ) ;
my_snprintf ( unique_filename , sizeof ( unique_filename ) , " %s.%llx.deleted " ,
name , tsc ) ;
if ( ! MoveFile ( name , unique_filename ) )
{
DBUG_PRINT ( " warning " , ( " moving %s to unique filename failed, error %u \n " ,
name , GetLastError ( ) ) ) ;
}
CloseHandle ( handle ) ;
DBUG_RETURN ( 0 ) ;
error :
my_osmaperr ( last_error ) ;
DBUG_RETURN ( - 1 ) ;
}
# endif
# endif
Vladislav Vaintroub
13 years ago