text: /* Copyright (c) 2000, 2012, Oracle and/or its affiliates
     Copyright (c) 2012, 2014, SkySQL Ab
  
     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 Street, Fifth Floor, Boston, MA  02110-1301, USA */
  
  #include "mysys_priv.h"
  #include <m_string.h>
  
  #ifdef __WIN__
  
  /*
    Check a file or path for accessability.
   
    SYNOPSIS
      file_access()
      path 	Path to file
      amode	Access method
   
    RETURN VALUES
    0    ok
    -1   error  (We use -1 as my_access is mapped to access on other platforms)
  */
  
  int my_access(const char *path, int amode) 
  { 
    DWORD attributes;
  
    attributes = GetFileAttributes(path);
    if (attributes == INVALID_FILE_ATTRIBUTES ||
        ((attributes & FILE_ATTRIBUTE_READONLY) && (amode & W_OK)))
    {
      my_errno= errno= EACCES;
      return -1;
    }
    return 0;
  }
  
  #endif /* __WIN__ */
  
  
  /*
    List of file names that causes problem on windows
  
    NOTE that one can also not have file names of type CON.TXT
    
    NOTE: it is important to keep "CLOCK$" on the first place,
    we skip it in check_if_legal_tablename.
  */
  static const char *reserved_names[]=
  {
    "CLOCK$",
    "CON", "PRN", "AUX", "NUL",
    "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9",
    "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9",
    NullS
  };
  
  #define MAX_RESERVED_NAME_LENGTH 6
  
  
  /*
    Looks up a null-terminated string in a list,
    case insensitively.
   
    SYNOPSIS
      str_list_find()
      list        list of items
      str         item to find
  
    RETURN
      0  ok
      1  reserved file name
  */
  static int str_list_find(const char **list, const char *str)
  {
    const char **name;
    for (name= list; *name; name++)
    {
      if (!my_strcasecmp(&my_charset_latin1, *name, str))
        return 1;
    }
    return 0;
  }
  
  
  /*
    A map for faster reserved_names lookup,
    helps to avoid loops in many cases.
    1 - can be the first letter
    2 - can be the second letter
    4 - can be the third letter
  */
  static char reserved_map[256]=
  {
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /*  !"#$%&'()*+,-./ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 0123456789:;<=>? */
    0,1,0,1,0,0,0,0,0,0,0,0,7,4,5,2, /* @ABCDEFGHIJKLMNO */
    3,0,2,0,4,2,0,0,4,0,0,0,0,0,0,0, /* PQRSTUVWXYZ[\]^_ */
    0,1,0,1,0,0,0,0,0,0,0,0,7,4,5,2, /* bcdefghijklmno */
    3,0,2,0,4,2,0,0,4,0,0,0,0,0,0,0, /* pqrstuvwxyz{|}~. */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* ................ */
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0  /* ................ */
  };
  
  
  /*
    Check if a table name may cause problems
   
    SYNOPSIS
      check_if_legal_tablename
      name 	Table name (without any extensions)
  
    DESCRIPTION
      We don't check 'CLOCK$' because dollar sign is encoded as @0024,
      making table file name 'CLOCK@0024', which is safe.
      This is why we start lookup from the second element
      (i.e. &reserver_name[1])
  
    RETURN
      0  ok
      1  reserved file name
  */
  
  int check_if_legal_tablename(const char *name)
  {
    DBUG_ENTER("check_if_legal_tablename");
    DBUG_RETURN((reserved_map[(uchar) name[0]] & 1) &&
                (reserved_map[(uchar) name[1]] & 2) &&
                (reserved_map[(uchar) name[2]] & 4) &&
                str_list_find(&reserved_names[1], name));
  }
  
  
  #ifdef __WIN__
  /**
    Checks if the drive letter supplied is valid or not. Valid drive
    letters are A to Z, both lower case and upper case.
  
    @param drive_letter : The drive letter to validate.
   
    @return TRUE if the drive exists, FALSE otherwise.
  */
  static my_bool does_drive_exists(char drive_letter)
  {
    DWORD drive_mask= GetLogicalDrives();
    drive_letter= toupper(drive_letter);
  
    return (drive_letter >= 'A' && drive_letter <= 'Z') &&
           (drive_mask & (0x1 << (drive_letter - 'A')));
  }
  
  /**
    Verifies if the file name supplied is allowed or not. On Windows
    file names with a colon (:) are not allowed because such file names
    store data in Alternate Data Streams which can be used to hide 
    the data.
    Apart from colon, other characters that are not allowed in filenames
    on Windows are greater/less sign, double quotes, forward slash, backslash,
    pipe and star characters.
  
    See MSDN documentation on filename restrictions.
  
    @param name contains the file name with or without path
    @param length contains the length of file name
    @param allow_current_dir TRUE if paths like C:foobar are allowed, 
                             FALSE otherwise
   
    @return TRUE if the file name is allowed, FALSE otherwise.
  */
  #define ILLEGAL_FILENAME_CHARS "<>:\"/\\|?*"
  
  my_bool is_filename_allowed(const char *name __attribute__((unused)),
                              size_t length __attribute__((unused)),
                              my_bool allow_current_dir __attribute__((unused)))
  {
    /* 
      For Windows, check if the file name contains : character.
      Start from end of path and search if the file name contains :
    */
    const char* ch = NULL;
    for (ch= name + length - 1; ch >= name; --ch)
    {
      if (FN_LIBCHAR == *ch || '/' == *ch)
        break;
      else if (':' == *ch)
      {
        /*
          File names like C:foobar.txt are allowed since the syntax means
          file foobar.txt in current directory of C drive. However file
          names likes CC:foobar are not allowed since this syntax means ADS
          foobar in file CC.
        */
        return (allow_current_dir && (ch - name == 1) && 
                does_drive_exists(*name));
      }
      else if (strchr(ILLEGAL_FILENAME_CHARS, *ch))
        return FALSE;
    }
    return TRUE;
  } /* is_filename_allowed */
  #endif  /* __WIN__ */
  
  #if defined(__WIN__) || defined(__EMX__)
  
  
  /*
    Check if a path will access a reserved file name that may cause problems
   
    SYNOPSIS
      check_if_legal_filename
      path 	Path to file
  
    RETURN
      0  ok
      1  reserved file name
  */
  
  int check_if_legal_filename(const char *path)
  {
    const char *end;
    const char **reserved_name;
    DBUG_ENTER("check_if_legal_filename");
  
    if (!is_filename_allowed(path, strlen(path), TRUE))
      DBUG_RETURN(1);
  
    path+= dirname_length(path);                  /* To start of filename */
    if (!(end= strchr(path, FN_EXTCHAR)))
      end= strend(path);
    if (path == end || (uint) (end - path) > MAX_RESERVED_NAME_LENGTH)
      DBUG_RETURN(0);                             /* Simplify inner loop */
  
    for (reserved_name= reserved_names; *reserved_name; reserved_name++)
    {
      const char *reserved= *reserved_name;       /* never empty */
      const char *name= path;
      
      do
      {
        if (*reserved != my_toupper(&my_charset_latin1, *name))
          break;
        if (++name == end && !reserved[1])
          DBUG_RETURN(1);                         /* Found wrong path */
      } while (*++reserved);
    }
    DBUG_RETURN(0);
  }
  
  #endif /* defined(__WIN__) || defined(__EMX__) */
  