CompleteEraser/FileBreaker.cs

   1 using System;\r
   2 using System.Text;\r
   3 using System.Collections.Generic;\r
   4 using System.IO;\r
   5 using System.Security.AccessControl;\r
   6 using System.Security.Principal;\r
   7 using System.Linq;\r
   8 using Trinet.Core.IO.Ntfs;\r
   9 using CompleteEraser.Properties;\r
  10 \r
  11 namespace CompleteEraser\r
  12 {\r
  13     class FileBreaker\r
  14     {\r
  15 \r
  16         public static void BreakFileOrFolder(string path)\r
  17         {\r
  18             if (Directory.Exists(path))\r
  19                 BreakFolder(path);\r
  20             else if (File.Exists(path))\r
  21                 BreakFile(path);\r
  22         }\r
  23 \r
  24         public static void BreakFile(string file)\r
  25         {\r
  26             FileAttributes attr = File.GetAttributes(file);\r
  27             if ((attr & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)\r
  28                 File.SetAttributes(file, attr & ~FileAttributes.ReadOnly);\r
  29 \r
  30             string ext = Path.GetExtension(file);\r
  31 \r
  32             FileStream fs;\r
  33             FileInfo info = new FileInfo(file);\r
  34             foreach (AlternateDataStreamInfo alt in info.ListAlternateDataStreams())\r
  35             {\r
  36                 fs = alt.Open(FileMode.Open);\r
  37                 BreakFileSlowSpeed(fs);\r
  38                 fs.Close();\r
  39             }\r
  40 \r
  41             fs = new FileStream(file, FileMode.Open);\r
  42             if (Settings.Default.AlwaysSlowSpeed || Settings.Default.SlowSpeedExt.IndexOf(ext) != -1)\r
  43                 BreakFileSlowSpeed(fs);\r
  44             else\r
  45                 BreakFileHiSpeed(fs);\r
  46             fs.Close();\r
  47 \r
  48             string newFile = GenerateRandoName(Path.GetDirectoryName(file), file.Length);\r
  49             File.Move(file, newFile);\r
  50             \r
  51             File.Delete(newFile);\r
  52         }\r
  53 \r
  54         private static void BreakFileSlowSpeed(FileStream fs)\r
  55         {\r
  56             if (BreakFileInMFTArea(fs))\r
  57                 return;\r
  58             fs.Seek(0, SeekOrigin.Begin);\r
  59             byte[] data = new byte[Settings.Default.FillLengthAtHiSpeed];\r
  60             for (long i = 0; i < fs.Length; i += data.Length)\r
  61                 fs.Write(data,0,data.Length);\r
  62         }\r
  63 \r
  64         private static void BreakFileHiSpeed(FileStream fs)\r
  65         {\r
  66             if (BreakFileInMFTArea(fs))\r
  67                 return;\r
  68             fs.Seek(0, SeekOrigin.Begin);\r
  69             byte[] data = new byte[Settings.Default.FillLengthAtHiSpeed];\r
  70             fs.Write(data, 0, data.Length);\r
  71             fs.Seek(-data.Length, SeekOrigin.End);\r
  72             fs.Write(data, 0, data.Length);\r
  73         }\r
  74 \r
  75         private static bool BreakFileInMFTArea(FileStream fs)\r
  76         {\r
  77             if (fs.Length >= 1024)  //MFTのレコードサイズ以上か\r
  78                 return false;\r
  79             fs.Seek(0, SeekOrigin.Begin);\r
  80             byte[] data = new byte[fs.Length];\r
  81             fs.Write(data, 0, data.Length);\r
  82             return true;\r
  83         }\r
  84 \r
  85         public static void BreakFolder(string folder)\r
  86         {\r
  87             IEnumerable<string> files = Directory.GetFiles(folder, "*.*", SearchOption.AllDirectories);\r
  88             foreach (string file in files)\r
  89                 BreakFile(file);\r
  90             string newName = GenerateRandoName(Path.GetDirectoryName(folder), Path.GetFileName(folder).Length);\r
  91             if ((FileAccessPermissionHelper.GetCurrentAccessRule(folder).FileSystemRights & FileSystemRights.Modify) == FileSystemRights.Modify)\r
  92                 Directory.Move(folder, newName);\r
  93             else\r
  94                 throw new UnauthorizedAccessException();\r
  95             Directory.Delete(newName, true);\r
  96         }\r
  97 \r
  98         private static string GenerateRandoName(string dirpath, int length)\r
  99         {\r
 100             string list = "abcdefghijklmnopqrstuvwxyz0123456789";\r
 101             Random rnd = new Random();\r
 102             StringBuilder output = new StringBuilder();\r
 103             for (int i = 0; i < length; i++)\r
 104                 output.Append(list[rnd.Next(list.Length - 1)]);\r
 105             return dirpath + "\\" + output.ToString();\r
 106         }\r
 107     }\r
 108 \r
 109     public static class FileAccessPermissionHelper\r
 110     {\r
 111         // 書き込み権限持ってる？\r
 112         public static bool IsGotPermission(string path)\r
 113         {\r
 114             var rule = GetCurrentAccessRule(path);\r
 115             return ((rule != null) && ((rule.FileSystemRights & FileSystemRights.Write) == FileSystemRights.Write));\r
 116         }\r
 117 \r
 118         // 現在のユーザーが持っている指定パスのFileSystemAccessRuleを得る\r
 119         public static FileSystemAccessRule GetCurrentAccessRule(string path)\r
 120         {\r
 121             var fileSecurity = File.GetAccessControl(path);\r
 122             var rules = fileSecurity.GetAccessRules(true, true, typeof(SecurityIdentifier)).OfType<FileSystemAccessRule>();\r
 123             var currentIdentity = WindowsIdentity.GetCurrent();\r
 124             var sids = new[] { currentIdentity.User }.Concat(currentIdentity.Groups);\r
 125 \r
 126             // アクセスルール内にユーザーSIDがある？無ければグループSIDも探す\r
 127             return rules.FirstOrDefault(rule => sids.Contains(rule.IdentityReference));\r
 128         }\r
 129     }\r
 130 }\r