release/src/router/mysql/mysys/mf_tempfile.c

   1 /* Copyright (c) 2000-2007 MySQL AB
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */
  15
  16 #include "mysys_priv.h"
  17 #include <m_string.h>
  18 #include "my_static.h"
  19 #include "mysys_err.h"
  20 #include <errno.h>
  21 #ifdef HAVE_PATHS_H
  22 #include <paths.h>
  23 #endif
  24
  25
  26
  27 /*
  28   @brief
  29   Create a temporary file with unique name in a given directory
  30
  31   @details
  32   create_temp_file
  33     to             pointer to buffer where temporary filename will be stored
  34     dir            directory where to create the file
  35     prefix         prefix the filename with this
  36     mode           Flags to use for my_create/my_open
  37     MyFlags        Magic flags
  38
  39   @return
  40     File descriptor of opened file if success
  41     -1 and sets errno if fails.
  42
  43   @note
  44     The behaviour of this function differs a lot between
  45     implementation, it's main use is to generate a file with
  46     a name that does not already exist.
  47
  48     When passing O_TEMPORARY flag in "mode" the file should
  49     be automatically deleted
  50
  51     The implementation using mkstemp should be considered the
  52     reference implementation when adding a new or modifying an
  53     existing one
  54
  55 */
  56
  57 File create_temp_file(char *to, const char *dir, const char *prefix,
  58                       int mode __attribute__((unused)),
  59                       myf MyFlags __attribute__((unused)))
  60 {
  61   File file= -1;
  62 #ifdef __WIN__
  63   TCHAR path_buf[MAX_PATH-14];
  64 #endif
  65
  66   DBUG_ENTER("create_temp_file");
  67   DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir, prefix));
  68 #if defined (__WIN__)
  69
  70    /*
  71      Use GetTempPath to determine path for temporary files.
  72      This is because the documentation for GetTempFileName
  73      has the following to say about this parameter:
  74      "If this parameter is NULL, the function fails."
  75    */
  76    if (!dir)
  77    {
  78      if(GetTempPath(sizeof(path_buf), path_buf) > 0)
  79        dir = path_buf;
  80    }
  81    /*
  82      Use GetTempFileName to generate a unique filename, create
  83      the file and release it's handle
  84       - uses up to the first three letters from prefix
  85    */
  86   if (GetTempFileName(dir, prefix, 0, to) == 0)
  87     DBUG_RETURN(-1);
  88
  89   DBUG_PRINT("info", ("name: %s", to));
  90
  91   /*
  92     Open the file without the "open only if file doesn't already exist"
  93     since the file has already been created by GetTempFileName
  94   */
  95   if ((file= my_open(to,  (mode & ~O_EXCL), MyFlags)) < 0)
  96   {
  97     /* Open failed, remove the file created by GetTempFileName */
  98     int tmp= my_errno;
  99     (void) my_delete(to, MYF(0));
 100     my_errno= tmp;
 101   }
 102
 103 #elif defined(_ZTC__)
 104   if (!dir)
 105     dir=getenv("TMPDIR");
 106   if ((res=tempnam((char*) dir,(char *) prefix)))
 107   {
 108     strmake(to,res,FN_REFLEN-1);
 109     (*free)(res);
 110     file=my_create(to, 0, mode | O_EXCL | O_NOFOLLOW, MyFlags);
 111   }
 112 #elif defined(HAVE_MKSTEMP) && !defined(__NETWARE__)
 113   {
 114     char prefix_buff[30];
 115     uint pfx_len;
 116     File org_file;
 117
 118     pfx_len= (uint) (strmov(strnmov(prefix_buff,
 119                                     prefix ? prefix : "tmp.",
 120                                     sizeof(prefix_buff)-7),"XXXXXX") -
 121                      prefix_buff);
 122     if (!dir && ! (dir =getenv("TMPDIR")))
 123       dir=P_tmpdir;
 124     if (strlen(dir)+ pfx_len > FN_REFLEN-2)
 125     {
 126       errno=my_errno= ENAMETOOLONG;
 127       DBUG_RETURN(file);
 128     }
 129     strmov(convert_dirname(to,dir,NullS),prefix_buff);
 130     org_file=mkstemp(to);
 131     if (mode & O_TEMPORARY)
 132       (void) my_delete(to, MYF(MY_WME | ME_NOINPUT));
 133     file=my_register_filename(org_file, to, FILE_BY_MKSTEMP,
 134                               EE_CANTCREATEFILE, MyFlags);
 135     /* If we didn't manage to register the name, remove the temp file */
 136     if (org_file >= 0 && file < 0)
 137     {
 138       int tmp=my_errno;
 139       close(org_file);
 140       (void) my_delete(to, MYF(MY_WME | ME_NOINPUT));
 141       my_errno=tmp;
 142     }
 143   }
 144 #elif defined(HAVE_TEMPNAM)
 145   {
 146 #if !defined(__NETWARE__)
 147     extern char **environ;
 148 #endif
 149
 150     char *res,**old_env,*temp_env[1];
 151     if (dir && !dir[0])
 152     {                           /* Change empty string to current dir */
 153       to[0]= FN_CURLIB;
 154       to[1]= 0;
 155       dir=to;
 156     }
 157 #if !defined(__NETWARE__)
 158     old_env= (char**) environ;
 159     if (dir)
 160     {                           /* Don't use TMPDIR if dir is given */
 161       environ=(const char**) temp_env;
 162       temp_env[0]=0;
 163     }
 164 #endif
 165     if ((res=tempnam((char*) dir, (char*) prefix)))
 166     {
 167       strmake(to,res,FN_REFLEN-1);
 168       (*free)(res);
 169       file=my_create(to,0,
 170                      (int) (O_RDWR | O_BINARY | O_TRUNC | O_EXCL | O_NOFOLLOW |
 171                             O_TEMPORARY | O_SHORT_LIVED),
 172                      MYF(MY_WME));
 173
 174     }
 175     else
 176     {
 177       DBUG_PRINT("error",("Got error: %d from tempnam",errno));
 178     }
 179 #if !defined(__NETWARE__)
 180     environ=(const char**) old_env;
 181 #endif
 182   }
 183 #else
 184 #error No implementation found for create_temp_file
 185 #endif
 186   if (file >= 0)
 187     thread_safe_increment(my_tmp_file_created,&THR_LOCK_open);
 188   DBUG_RETURN(file);
 189 }