mysql5/mysql-5.7.27/mysys/mf_tempfile.c

141 lines
4.1 KiB
C

/* Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include "mysys_priv.h"
#include <m_string.h>
#include "my_static.h"
#include "mysys_err.h"
#include <errno.h>
#include "my_thread_local.h"
/*
@brief
Create a temporary file with unique name in a given directory
@details
create_temp_file
to pointer to buffer where temporary filename will be stored
dir directory where to create the file
prefix prefix the filename with this
mode Flags to use for my_create/my_open
MyFlags Magic flags
@return
File descriptor of opened file if success
-1 and sets errno if fails.
@note
The behaviour of this function differs a lot between
implementation, it's main use is to generate a file with
a name that does not already exist.
When passing O_TEMPORARY flag in "mode" the file should
be automatically deleted
The implementation using mkstemp should be considered the
reference implementation when adding a new or modifying an
existing one
*/
File create_temp_file(char *to, const char *dir, const char *prefix,
int mode, myf MyFlags)
{
File file= -1;
#ifdef _WIN32
TCHAR path_buf[MAX_PATH-14];
#endif
DBUG_ENTER("create_temp_file");
DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir, prefix));
#if defined(_WIN32)
/*
Use GetTempPath to determine path for temporary files.
This is because the documentation for GetTempFileName
has the following to say about this parameter:
"If this parameter is NULL, the function fails."
*/
if (!dir)
{
if(GetTempPath(sizeof(path_buf), path_buf) > 0)
dir = path_buf;
}
/*
Use GetTempFileName to generate a unique filename, create
the file and release it's handle
- uses up to the first three letters from prefix
*/
if (GetTempFileName(dir, prefix, 0, to) == 0)
DBUG_RETURN(-1);
DBUG_PRINT("info", ("name: %s", to));
/*
Open the file without the "open only if file doesn't already exist"
since the file has already been created by GetTempFileName
*/
if ((file= my_open(to, (mode & ~O_EXCL), MyFlags)) < 0)
{
/* Open failed, remove the file created by GetTempFileName */
int tmp= my_errno();
(void) my_delete(to, MYF(0));
set_my_errno(tmp);
}
#else /* mkstemp() is available on all non-Windows supported platforms. */
{
char prefix_buff[30];
uint pfx_len;
File org_file;
pfx_len= (uint) (my_stpcpy(my_stpnmov(prefix_buff,
prefix ? prefix : "tmp.",
sizeof(prefix_buff)-7),"XXXXXX") -
prefix_buff);
if (!dir && ! (dir =getenv("TMPDIR")))
dir= DEFAULT_TMPDIR;
if (strlen(dir)+ pfx_len > FN_REFLEN-2)
{
errno=ENAMETOOLONG;
set_my_errno(ENAMETOOLONG);
DBUG_RETURN(file);
}
my_stpcpy(convert_dirname(to,dir,NullS),prefix_buff);
org_file=mkstemp(to);
if (mode & O_TEMPORARY)
(void) my_delete(to, MYF(MY_WME));
file=my_register_filename(org_file, to, FILE_BY_MKSTEMP,
EE_CANTCREATEFILE, MyFlags);
/* If we didn't manage to register the name, remove the temp file */
if (org_file >= 0 && file < 0)
{
int tmp=my_errno();
close(org_file);
(void) my_delete(to, MYF(MY_WME));
set_my_errno(tmp);
}
}
#endif
if (file >= 0)
{
mysql_mutex_lock(&THR_LOCK_open);
my_tmp_file_created++;
mysql_mutex_unlock(&THR_LOCK_open);
}
DBUG_RETURN(file);
}