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Unix.cs
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Unix.cs
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// Unix.cs
// Copyright © 2019-2020 Kenneth Gober
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// Unix File System Structure
//
// https://www.tuhs.org/Archive/Distributions/Research/Dennis_v5/v5man.pdf
// https://archive.org/download/v6-manual/v6-manual.pdf
// http://web.cuzuco.com/~cuzuco/v7/v7vol1.pdf
// http://web.cuzuco.com/~cuzuco/v7/v7vol2b.pdf
//
// The Unix v5 file system format is described by the "FILE SYSTEM(V)" man page.
// The v6 format is similar, except that the maximum file size increases from
// 1048576 to 16777216 by changing the last indirect block to doubly indirect.
// The formats are identical as long as no file is larger than 917504 bytes. If
// the largest file is between 917505 and 1048576 bytes inclusive, the formats
// can be (mostly) differentiated by looking at the last indirect block.
//
// The Unix v7 file system format increases block pointers to 24 bits, and
// increases the size of an i-node to contain additional block pointers. The
// 'large file' flag is removed; i-node block pointers are interpreted the same
// way for all files: 10 direct pointers, then 1 indirect, 1 double-indirect,
// and 1 triple-indirect pointer. Each indirect block contains 128 4-byte
// pointers, so the maximum file size increases to:
// 512 * (10 + 128 + 128*128 + 128*128*128) = 1082201087 bytes
//
// 2.8BSD doubles the block size to 1024 bytes. As a result, each indirect
// block contains 256 4-byte pointers.
//
// 2.11BSD changes the i-node format to contain 4 direct pointers rather than
// 10, but the size pointers (both direct and indirect) are increased from 3
// bytes each to 4. Additionally, 2.11BSD changes the format of directories
// to support file names up to 63 characters.
// Improvements / To Do
// decouple block size, inode and directory format to reuse more v5/v7/2BSD code
// in Test, check for duplicate names in a directory
// relax link count check for inodes (file systems are readable despite this)
// relax block allocation checks (file systems are readable despite this)
// support BSD Fast File System (FFS)
// allow files to be written/deleted in images
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
namespace FSX
{
class Inode
{
protected Volume mVol;
public Int32 iNum;
public UInt16 flags;
public Int16 nlinks;
public Int16 uid;
public Int16 gid;
public Int32 size;
public Int32[] addr;
public DateTime atime;
public DateTime mtime;
public DateTime ctime;
public Inode(Volume volume, Int32 iNumber)
{
mVol = volume;
iNum = iNumber;
}
public Volume Volume
{
get { return mVol; }
}
public virtual Char Type
{
get { return '\0'; }
}
public virtual String Mode
{
get { return null; }
}
public virtual Int32 this[Int32 blockNum]
{
get { return 0; }
}
}
// v5/v6 super block
// 0 isize - i-list size (in blocks)
// 2 fsize - file system size
// 4 nfree - number of free blocks listed in superblock (0-100)
// 6 free - free block list
// 206 ninode - number of fre einodes listed in superblock (0-100)
// 208 inode - free inode list
// 408 flock
// 409 ilock
// 410 fmod
// 411 time
// 415
//
// v5/v6 i-node flags
// 0x8000 allocated / in use
// 0x6000 file type (file=0x0000 cdev=0x2000 dir=0x4000 bdev=0x6000)
// 0x1000 large file (addr[] has indirect blocks, instead of direct)
// 0x0800 setuid
// 0x0400 setgid
// 0x01c0 owner permissions (r=0x0100 w=0x0080 x=0x0040)
// 0x0038 group permissions (r=0x0020 w=0x0010 x=0x0008)
// 0x0007 world permissions (r=0x0004 w=0x0002 x=0x0001)
partial class UnixV5 : FileSystem
{
protected class InodeV5 : Inode
{
public InodeV5(Volume volume, Int32 iNumber) : base(volume, iNumber)
{
Block B = volume[2 + (iNumber - 1) / 16];
Int32 offset = ((iNumber - 1) % 16) * 32;
flags = B.GetUInt16L(ref offset);
nlinks = B.GetByte(ref offset);
uid = B.GetByte(ref offset);
gid = B.GetByte(ref offset);
size = B.GetByte(ref offset) << 16;
size |= B.GetUInt16L(ref offset);
addr = new Int32[8];
for (Int32 i = 0; i < 8; i++) addr[i] = B.GetUInt16L(ref offset);
atime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddSeconds(B.GetInt32P(ref offset));
mtime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddSeconds(B.GetInt32P(ref offset));
}
public override Char Type
{
get
{
if ((flags & 0xe000) == 0x8000) return '-';
if ((flags & 0xe000) == 0xc000) return 'd';
if ((flags & 0xe000) == 0xa000) return 'c';
if ((flags & 0xe000) == 0xe000) return 'b';
return ' ';
}
}
public override String Mode
{
get
{
StringBuilder buf = new StringBuilder(9);
buf.Append(((flags & 0x0100) == 0) ? '-' : 'r');
buf.Append(((flags & 0x0080) == 0) ? '-' : 'w');
buf.Append(((flags & 0x0040) == 0) ? '-' : ((flags & 0x0800) == 0) ? 'x' : 's');
buf.Append(((flags & 0x0020) == 0) ? '-' : 'r');
buf.Append(((flags & 0x0010) == 0) ? '-' : 'w');
buf.Append(((flags & 0x0008) == 0) ? '-' : ((flags & 0x0400) == 0) ? 'x' : 's');
buf.Append(((flags & 0x0004) == 0) ? '-' : 'r');
buf.Append(((flags & 0x0002) == 0) ? '-' : 'w');
buf.Append(((flags & 0x0001) == 0) ? '-' : 'x');
return buf.ToString();
}
}
public override Int32 this[Int32 blockNum]
{
get
{
if ((flags & 0x1000) == 0) return addr[blockNum];
Block B = mVol[addr[blockNum / 256]];
return B.GetUInt16L(2 * (blockNum % 256));
}
}
}
protected Int32 BLOCK_SIZE = 512;
protected Int32 ROOT_INUM = 1;
protected Int32 INOPB = 16;
protected Int32 ISIZE = 32;
protected Volume mVol;
protected String mType;
protected Inode mDirNode;
protected String mDir;
protected UnixV5()
{
}
public UnixV5(Volume volume)
{
mVol = volume;
mType = "Unix/V5";
mDirNode = new InodeV5(volume, ROOT_INUM);
mDir = "/";
}
public override String Source
{
get { return mVol.Source; }
}
public override String Type
{
get { return mType; }
}
public override String Info
{
get { return mVol.Info; }
}
public override String Dir
{
get { return mDir; }
}
public override Encoding DefaultEncoding
{
get { return Encoding.ASCII; }
}
public override void ChangeDir(String dirSpec)
{
Inode dirNode;
String dirName;
if (!FindFile(dirSpec, out dirNode, out dirName))
{
Console.Error.WriteLine("Not found: {0}", dirSpec);
return;
}
if (dirNode.Type != 'd')
{
Console.Error.WriteLine("Not a directory: {0}", dirName);
return;
}
mDirNode = dirNode;
mDir = dirName;
}
public override void ListDir(String fileSpec, TextWriter output)
{
Int32 p;
Inode dirNode = mDirNode;
String dirName = mDir;
if ((fileSpec == null) || (fileSpec.Length == 0))
{
fileSpec = "*";
}
else if ((p = fileSpec.LastIndexOf('/')) == 0)
{
dirNode = GetInode(ROOT_INUM);
dirName = "/";
while ((fileSpec.Length != 0) && (fileSpec[0] == '/')) fileSpec = fileSpec.Substring(1);
if (fileSpec.Length == 0) fileSpec = "*";
}
else if (p != -1)
{
if ((!FindFile(fileSpec.Substring(0, p), out dirNode, out dirName)) || (dirNode.Type != 'd'))
{
Console.Error.WriteLine("Not found: {0}", fileSpec);
return;
}
fileSpec = fileSpec.Substring(p + 1);
while ((fileSpec.Length != 0) && (fileSpec[0] == '/')) fileSpec = fileSpec.Substring(1);
if (fileSpec.Length == 0) fileSpec = "*";
}
// if fileSpec names a single directory, show the content of that directory
Inode iNode;
String pathName;
if ((FindDirEntry(dirNode, dirName, fileSpec, out iNode, out pathName)) && (iNode.Type == 'd'))
{
dirNode = iNode;
dirName = pathName;
fileSpec = "*";
output.WriteLine("{0}:", pathName);
}
// count number of blocks used
Int32 n = 0;
Regex RE = Regex(fileSpec);
Byte[] data = ReadFile(dirNode, BLOCK_SIZE);
for (Int32 bp = 0; bp < data.Length; bp += 16)
{
Int32 iNum = Buffer.GetUInt16L(data, bp);
if (iNum == 0) continue;
String name = Buffer.GetCString(data, bp + 2, 14, Encoding.ASCII);
if (!RE.IsMatch(name)) continue;
iNode = GetInode(iNum);
n += (iNode.size + 511) / 512;
}
// show directory listing
output.WriteLine("total {0:D0}", n);
for (Int32 bp = 0; bp < data.Length; bp += 16)
{
Int32 iNum = Buffer.GetUInt16L(data, bp);
if (iNum == 0) continue;
String name = Buffer.GetCString(data, bp + 2, 14, Encoding.ASCII);
if (!RE.IsMatch(name)) continue;
iNode = GetInode(iNum);
Char ft = iNode.Type;
switch (ft)
{
case '-':
case 'd':
output.WriteLine("{0,5:D0} {1}{2} {3,2:D0} {4,-5} {5,7:D0} {6} {7,-14}", iNum, ft, iNode.Mode, iNode.nlinks, iNode.uid.ToString(), iNode.size, iNode.mtime.ToString("MM/dd/yyyy HH:mm"), name);
break;
case 'b':
case 'c':
output.WriteLine("{0,5:D0} {1}{2} {3,2:D0} {4,-5} {5,3:D0},{6,3:D0} {7} {8,-14}", iNum, ft, iNode.Mode, iNode.nlinks, iNode.uid.ToString(), iNode.addr[0] >> 8, iNode.addr[0] & 0x00ff, iNode.mtime.ToString("MM/dd/yyyy HH:mm"), name);
break;
}
}
}
public override void DumpDir(String fileSpec, TextWriter output)
{
ListDir(fileSpec, output);
}
public override void ListFile(String fileSpec, Encoding encoding, TextWriter output)
{
Inode iNode;
String name;
if (!FindFile(fileSpec, out iNode, out name)) return;
String buf = encoding.GetString(ReadFile(iNode, BLOCK_SIZE));
Int32 p = 0;
for (Int32 i = 0; i < buf.Length; i++)
{
if (buf[i] != '\n') continue;
output.WriteLine(buf.Substring(p, i - p));
p = i + 1;
}
}
public override void DumpFile(String fileSpec, TextWriter output)
{
Inode iNode;
String name;
if (!FindFile(fileSpec, out iNode, out name)) return;
Program.Dump(null, ReadFile(iNode, BLOCK_SIZE), output, 16, BLOCK_SIZE, Program.DumpOptions.ASCII);
}
public override String FullName(String fileSpec)
{
Inode iNode;
String name;
if (!FindFile(fileSpec, out iNode, out name)) return null;
return name;
}
public override Byte[] ReadFile(String fileSpec)
{
Inode iNode;
String name;
if (!FindFile(fileSpec, out iNode, out name)) return null;
return ReadFile(iNode, BLOCK_SIZE);
}
public override Boolean SaveFS(String fileName, String format)
{
if ((fileName == null) || (fileName.Length == 0)) return false;
FileStream f = new FileStream(fileName, FileMode.Create);
Byte[] buf = new Byte[BLOCK_SIZE];
for (Int32 i = 0; i < mVol.BlockCount; i++)
{
mVol[i].CopyTo(buf, 0);
f.Write(buf, 0, BLOCK_SIZE);
}
f.Close();
return true;
}
protected virtual Inode GetInode(Int32 iNumber)
{
return new InodeV5(mVol, iNumber);
}
protected Boolean FindFile(String pathSpec, out Inode iNode, out String pathName)
{
iNode = mDirNode;
pathName = mDir;
if ((pathSpec == null) || (pathSpec.Length == 0)) return false;
if (pathSpec[0] == '/')
{
iNode = GetInode(ROOT_INUM);
pathName = "/";
while (pathSpec[0] == '/')
{
pathSpec = pathSpec.Substring(1);
if (pathSpec.Length == 0) return true;
}
}
while (pathSpec.Length != 0)
{
String s;
Int32 p = pathSpec.IndexOf('/');
if (p == -1)
{
s = pathSpec;
pathSpec = String.Empty;
}
else
{
s = pathSpec.Substring(0, p);
pathSpec = pathSpec.Substring(p);
}
if (!FindDirEntry(iNode, pathName, s, out iNode, out pathName)) return false;
if ((pathSpec.Length != 0) && (iNode.Type != 'd')) return false;
while ((pathSpec.Length != 0) && (pathSpec[0] == '/')) pathSpec = pathSpec.Substring(1);
}
return true;
}
protected virtual Boolean FindDirEntry(Inode dirNode, String dirName, String entryName, out Inode iNode, out String pathName)
{
iNode = null;
pathName = null;
Int32 n = 0;
Regex RE = Regex(entryName);
Byte[] dir = ReadFile(dirNode, BLOCK_SIZE);
for (Int32 dp = 0; dp < dir.Length; dp += 16)
{
Int32 iNum = Buffer.GetUInt16L(dir, dp);
if (iNum == 0) continue;
String name = Buffer.GetCString(dir, dp + 2, 14, Encoding.ASCII);
if (RE.IsMatch(name))
{
n++;
iNode = GetInode(iNum);
if ((name == ".") || ((name == "..") && (dirName == "/")))
{
pathName = dirName;
}
else if (name == "..")
{
pathName = dirName.Substring(0, dirName.Length - 1);
pathName = pathName.Substring(0, pathName.LastIndexOf('/') + 1);
}
else
{
pathName = String.Concat(dirName, name, (iNode.Type == 'd') ? "/" : null);
}
}
}
return (n == 1);
}
}
partial class UnixV5
{
protected static Byte[] ReadFile(Inode iNode, Int32 blockSize)
{
Byte[] buf = new Byte[iNode.size];
Int32 bp = 0;
while (bp < buf.Length)
{
Int32 n = bp / blockSize; // file block number
Int32 b = iNode[n]; // volume block number
if (b != 0) iNode.Volume[b].CopyTo(buf, bp);
bp += blockSize;
}
return buf;
}
protected static Regex Regex(String pattern)
{
String p = pattern;
p = p.Replace(".", "\ufffd");
p = p.Replace("?", ".").Replace("*", @".*");
p = p.Replace("\ufffd", "\\.");
p = String.Concat("^", p, "$");
Debug.WriteLine(2, "Regex: {0} => {1}", pattern, p);
return new Regex(p);
}
}
partial class UnixV5 : IFileSystemAuto
{
public static TestDelegate GetTest()
{
return UnixV5.Test;
}
// level 0 - check basic volume parameters (return required block size and volume type)
// level 1 - check boot block (return volume size and type)
// level 2 - check volume descriptor (aka home/super block) (return file system size and type)
// level 3 - check file headers (aka inodes) (return file system size and type)
// level 4 - check directory structure (return file system size and type)
// level 5 - check file header allocation (return file system size and type)
// level 6 - check data block allocation (return file system size and type)
public static Boolean Test(Volume volume, Int32 level, out Int32 size, out Type type)
{
Int32 BLOCK_SIZE = 512;
Int32 ROOT_INUM = 1;
Int32 INOPB = 16;
// level 0 - check basic volume parameters (return required block size and volume type)
size = BLOCK_SIZE;
type = typeof(Volume);
if (volume == null) return false;
if (volume.BlockSize != size) return Debug.WriteInfo(false, "UnixV5.Test: invalid block size (is {0:D0}, require {1:D0})", volume.BlockSize, size);
if (level == 0) return true;
// level 1 - check boot block (return volume size and type)
size = -1; // Unix V5 doesn't support disk labels
if (volume.BlockCount < 1) return Debug.WriteInfo(false, "UnixV5.Test: volume too small to contain boot block");
if (level == 1) return true;
// level 2 - check volume descriptor (aka home/super block) (return file system size and type)
type = null;
if (volume.BlockCount < 2) return Debug.WriteInfo(false, "UnixV5.Test: volume too small to contain super-block");
Block SB = volume[1]; // super-block
Int32 bp = 0;
Int32 isize = SB.GetUInt16L(ref bp); // SB[0] - number of blocks used for inodes
if (volume.BlockCount < isize + 2) return Debug.WriteInfo(false, "UnixV5.Test: volume too small to contain i-node list (blocks {0:D0}-{1:D0} > {2:D0})", 2, isize + 1, volume.BlockCount - 1);
Int32 fsize = SB.GetUInt16L(ref bp); // SB[2] - file system size (in blocks)
if (isize + 2 > fsize) return Debug.WriteInfo(false, "UnixV5.Test: super-block i-list exceeds file system size ({0:D0} > {1:D0})", isize + 2, fsize);
Int32 n = SB.GetUInt16L(ref bp); // SB[4] - number of blocks in super-block free block list
if (n > 100) return Debug.WriteInfo(false, "UnixV5.Test: super-block free block count invalid (is {0:D0}, require 0 <= n <= 100)", n);
Int32 p = SB.GetUInt16L(bp); // SB[6] - free block chain next pointer
if ((p != 0) && ((p < isize + 2) || (p >= fsize))) return Debug.WriteInfo(false, "UnixV5.Test: super-block free chain pointer invalid (is {0:D0}, require {1:D0} <= n < {2:D0})", p, isize + 2, fsize);
for (Int32 i = 1; i < n; i++) // SB[8] - free block list
{
if (((p = SB.GetUInt16L(bp + 2 * i)) < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV5.Test: super-block free block {0:D0} invalid (is {1:D0}, require {2:D0} <= n < {3:D0})", i, p, isize + 2, fsize);
}
bp += 100 * 2;
n = SB.GetUInt16L(ref bp); // SB[206] - number of inodes in super-block free inode list
if (n > 100) return Debug.WriteInfo(false, "UnixV5.Test: super-block free i-node count invalid (is {0:D0}, require 0 <= n <= 100)", n);
for (Int32 i = 0; i < n; i++)
{
if (((p = SB.GetUInt16L(bp + 2 * i)) < 1) || (p > isize * INOPB)) return Debug.WriteInfo(false, "UnixV5.Test: super-block free i-number {0:D0} invalid (is {1:D0}, require 1 <= n < {2:D0})", i, p, isize * INOPB);
}
size = fsize;
type = typeof(UnixV5);
if (level == 2) return Debug.WriteInfo(true, "UnixV5.Test: file system size: {0:D0} blocks ({1:D0} i-nodes in blocks 2-{2:D0}, data in blocks {3:D0}-{4:D0}", fsize, isize * INOPB, isize + 1, isize + 2, fsize - 1);
// level 3 - check file headers (aka inodes) (return file system size and type)
Inode iNode;
for (UInt16 iNum = 1; iNum <= isize * INOPB; iNum++)
{
iNode = new InodeV5(volume, iNum);
if ((iNode.Type != ' ') && (iNode.nlinks == 0)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} is used but has zero link count", iNum);
//if ((iNode.Type == ' ') && (iNode.nlinks != 0)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} is free but has non-zero link count {1:D0}", iNum, iNode.nlinks);
if ((iNode.size < 0) || (iNode.size > 1048576)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} size invalid (is {1:D0}, require 0 <= n <= 1048576)", iNum, iNode.size);
if ((iNode.Type == ' ') && (iNode.size != 0)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} is free but has non-zero size {1:D0}", iNum, iNode.size);
if (((iNode.flags & 0x1000) == 0) && (iNode.size > 4096)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} size exceeds small file limit (is {1:D0}, require n <= 4096)", iNum, iNode.size);
if ((iNode.Type != '-') && (iNode.Type != 'd')) continue; // only check blocks for file and directory i-nodes
for (Int32 i = 0; i < 8; i++)
{
if ((p = iNode.addr[i]) == 0) continue;
if ((p < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} contains invalid block pointer (is {1:D0}, require {2:D0} <= n < {3:D0})", iNum, p, isize + 2, fsize);
if (p >= volume.BlockCount) return Debug.WriteInfo(false, "UnixV5.Test: volume too small to contain i-node {0:D0} {1} block {2:D0}", iNum, ((iNode.flags & 0x1000) == 0) ? "data" : "indirect", p);
if ((iNode.flags & 0x1000) != 0)
{
Block B = volume[p];
for (Int32 j = 0; j < 256; j++)
{
if ((p = B.GetUInt16L(2 * j)) == 0) continue;
if ((p < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} contains invalid block pointer (is {1:D0}, require {2:D0} <= n < {3:D0})", iNum, p, isize + 2, fsize);
if (p >= volume.BlockCount) return Debug.WriteInfo(false, "UnixV5.Test: volume too small to contain i-node {0:D0} data block {1:D0}", iNum, p);
}
}
}
}
if (level == 3) return true;
// level 4 - check directory structure (return file system size and type)
iNode = new InodeV5(volume, ROOT_INUM);
if (iNode.Type != 'd') return Debug.WriteInfo(false, "UnixV5.Test: root directory i-node mode invalid (is 0x{0:x4}, require 0xcnnn)", iNode.flags);
UInt16[] IMap = new UInt16[isize * INOPB + 1]; // inode usage map
Queue<Int32> DirList = new Queue<Int32>(); // queue of directories to examine
DirList.Enqueue((ROOT_INUM << 16) + ROOT_INUM); // parent inum in high word, directory inum in low word (root is its own parent)
while (DirList.Count != 0)
{
Int32 dNum = DirList.Dequeue();
Int32 pNum = dNum >> 16;
dNum &= 0xffff;
if (IMap[dNum] != 0) return Debug.WriteInfo(false, "UnixV5.Test: directory i-node {0:D0} appears more than once in directory structure", dNum);
IMap[dNum]++; // assume a link to this directory from its parent (root directory gets fixed later)
Byte[] buf = ReadFile(new InodeV5(volume, dNum), BLOCK_SIZE);
Boolean df = false;
Boolean ddf = false;
for (bp = 0; bp < buf.Length; bp += 16)
{
UInt16 iNum = Buffer.GetUInt16L(buf, bp);
if (iNum == 0) continue;
String name = Buffer.GetCString(buf, bp + 2, 14, Encoding.ASCII);
if (String.Compare(name, ".") == 0)
{
if (iNum != dNum) return Debug.WriteInfo(false, "UnixV5.Test: in directory i={0:D0}, entry \".\" does not refer to itself (is {1:D0}, require {2:D0})", dNum, iNum, dNum);
IMap[iNum]++;
df = true;
}
else if (String.Compare(name, "..") == 0)
{
if (iNum != pNum) return Debug.WriteInfo(false, "UnixV5.Test: in directory i={0:D0}, entry \"..\" does not refer to parent (is {1:D0}, require {2:D0})", dNum, iNum, pNum);
IMap[iNum]++;
ddf = true;
}
else if ((iNum < 2) || (iNum > isize * INOPB))
{
return Debug.WriteInfo(false, "UnixV5.Test: in directory i={0:D0}, entry \"{1}\" has invalid i-number (is {2:D0}, require 2 <= n <= {3:D0})", dNum, name, iNum, isize * INOPB);
}
else if ((iNode = new InodeV5(volume, iNum)).Type == 'd') // directory
{
DirList.Enqueue((dNum << 16) + iNum);
}
else // non-directory
{
IMap[iNum]++;
}
}
if (!df) return Debug.WriteInfo(false, "UnixV5.Test: in directory i={0:D0}, entry \".\" is missing", dNum);
if (!ddf) return Debug.WriteInfo(false, "UnixV5.Test: in directory i={0:D0}, entry \"..\" is missing", dNum);
}
IMap[ROOT_INUM]--; // root directory has no parent, so back out the assumed parent link
if (level == 4) return true;
// level 5 - check file header allocation (return file system size and type)
for (UInt16 iNum = 1; iNum <= isize * INOPB; iNum++)
{
iNode = new InodeV5(volume, iNum);
if ((iNode.Type == ' ') && (IMap[iNum] != 0)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} is free but has {1:D0} link(s)", iNum, IMap[iNum]);
if ((iNode.Type != ' ') && (IMap[iNum] == 0)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} is used but has no links", iNum);
if ((iNode.Type != ' ') && (IMap[iNum] != iNode.nlinks)) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} link count mismatch (is {1:D0}, expect {2:D0})", iNum, iNode.nlinks, IMap[iNum]);
}
// also check super-block free list
bp = 206;
n = SB.GetUInt16L(ref bp);
for (Int32 i = 0; i < n; i++)
{
UInt16 iNum = SB.GetUInt16L(ref bp);
if (IMap[iNum] != 0) return Debug.WriteInfo(false, "UnixV5.Test: i-node {0:D0} is in super-block free list, but has {1:D0} link(s)", iNum, IMap[iNum]);
}
if (level == 5) return true;
// level 6 - check data block allocation (return file system size and type)
UInt16[] BMap = new UInt16[fsize]; // block usage map
for (UInt16 iNum = 1; iNum <= isize * INOPB; iNum++)
{
iNode = new InodeV5(volume, iNum);
if ((iNode.Type != '-') && (iNode.Type != 'd')) continue; // only file and directory i-nodes have blocks allocated
n = (iNode.size + 511) / 512; // number of blocks required for file
// mark data blocks used
for (Int32 i = 0; i < n; i++)
{
if ((p = iNode[i]) == 0) continue;
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV5.Test: data block #{0:D0} ({1:D0}) of i-node {2:D0} is also allocated to i-node {3:D0}", i, p, iNum, BMap[p]);
BMap[p] = iNum;
}
if ((iNode.flags & 0x1000) == 0) continue; // small files have no indirect blocks
// mark indirect blocks used
for (Int32 i = 0; i < 8; i++)
{
if ((p = iNode.addr[i]) == 0) continue;
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV5.Test: indirect block {0:D0} of i-node {1:D0} is also allocated to i-node {2:D0}", p, iNum, BMap[p]);
BMap[p] = iNum;
}
}
// mark used blocks with 1
for (Int32 i = 0; i < isize + 2; i++) BMap[i] = 1;
for (Int32 i = isize + 2; i < fsize; i++) if (BMap[i] != 0) BMap[i] = 1;
// mark free blocks with 2
bp = 4;
n = SB.GetUInt16L(ref bp); // number of blocks in super-block free block list
if ((p = SB.GetUInt16L(ref bp)) != 0) // free block chain next pointer
{
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV5.Test: list block {0:D0} in super-block free list is allocated", p);
BMap[p] = 2;
}
for (Int32 i = 1; i < n; i++)
{
Int32 q = SB.GetUInt16L(ref bp);
if (BMap[q] != 0) return Debug.WriteInfo(false, "UnixV5.Test: data block {0:D0} in super-block free list is allocated", q);
BMap[q] = 2;
}
// enumerate blocks in free block chain
while (p != 0)
{
Block B = volume[p];
bp = 0;
n = B.GetUInt16L(ref bp); // number of entries listed in this block
if ((p = B.GetUInt16L(ref bp)) != 0)
{
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV5.Test: list block {0:D0} in free block chain is allocated", p);
BMap[p] = 2;
}
for (Int32 i = 1; i < n; i++)
{
Int32 q = B.GetUInt16L(ref bp);
if ((q < isize + 2) || (q >= fsize)) return Debug.WriteInfo(false, "UnixV5.Test: data block {0:D0} in free block chain falls outside volume block range (require {1:D0} <= n < {2:D0})", q, isize + 2, fsize);
if (BMap[q] != 0) return Debug.WriteInfo(false, "UnixV5.Test: data block {0:D0} in free block chain is allocated", q);
BMap[q] = 2;
}
}
// unmarked blocks are lost -- not allocated and not in free list
for (Int32 i = 0; i < fsize; i++)
{
if (BMap[i] == 0) return Debug.WriteInfo(false, "UnixV5.Test: block {0:D0} is not allocated and not in free list", i);
}
if (level == 6) return true;
return false;
}
}
partial class UnixV6 : UnixV5
{
protected class InodeV6 : InodeV5
{
public InodeV6(Volume volume, Int32 iNumber) : base(volume, iNumber)
{
}
public override Int32 this[Int32 blockNum]
{
get
{
if ((flags & 0x1000) == 0) return addr[blockNum];
Int32 n = blockNum / 256;
if (n < 7) n = addr[n];
else if (addr[7] == 0) return 0;
else n = mVol[addr[7]].GetUInt16L(2 * (n - 7));
return mVol[n].GetUInt16L(2 * (blockNum % 256));
}
}
}
public UnixV6(Volume volume)
{
mVol = volume;
mType = "Unix/V6";
mDirNode = new InodeV6(volume, ROOT_INUM);
mDir = "/";
}
protected override Inode GetInode(Int32 iNumber)
{
return new InodeV6(mVol, iNumber);
}
}
partial class UnixV6 : IFileSystemAuto
{
public static new TestDelegate GetTest()
{
return UnixV6.Test;
}
// level 0 - check basic volume parameters (return required block size and volume type)
// level 1 - check boot block (return volume size and type)
// level 2 - check volume descriptor (aka home/super block) (return file system size and type)
// level 3 - check file headers (aka inodes) (return file system size and type)
// level 4 - check directory structure (return file system size and type)
// level 5 - check file header allocation (return file system size and type)
// level 6 - check data block allocation (return file system size and type)
public static new Boolean Test(Volume volume, Int32 level, out Int32 size, out Type type)
{
Int32 BLOCK_SIZE = 512;
Int32 ROOT_INUM = 1;
Int32 INOPB = 16;
// level 0 - check basic volume parameters (return required block size and volume type)
size = BLOCK_SIZE;
type = typeof(Volume);
if (volume == null) return false;
if (volume.BlockSize != size) return Debug.WriteInfo(false, "UnixV6.Test: invalid block size (is {0:D0}, require {1:D0})", volume.BlockSize, size);
if (level == 0) return true;
// level 1 - check boot block (return volume size and type)
size = -1; // Unix V6 doesn't support disk labels
if (volume.BlockCount < 1) return Debug.WriteInfo(false, "UnixV6.Test: volume too small to contain boot block");
if (level == 1) return true;
// level 2 - check volume descriptor (aka home/super block) (return file system size and type)
type = null;
if (volume.BlockCount < 2) return Debug.WriteInfo(false, "UnixV6.Test: volume too small to contain super-block");
Block SB = volume[1]; // super-block
Int32 bp = 0;
Int32 isize = SB.GetUInt16L(ref bp); // SB[0] - number of blocks used for inodes
if (volume.BlockCount < isize + 2) return Debug.WriteInfo(false, "UnixV6.Test: volume too small to contain i-node list (blocks {0:D0}-{1:D0} > {2:D0})", 2, isize + 1, volume.BlockCount - 1);
Int32 fsize = SB.GetUInt16L(ref bp); // SB[2] - file system size (in blocks)
if (isize + 2 > fsize) return Debug.WriteInfo(false, "UnixV6.Test: super-block i-list exceeds file system size ({0:D0} > {1:D0})", isize + 2, fsize);
Int32 n = SB.GetUInt16L(ref bp); // SB[4] - number of blocks in super-block free block list
if (n > 100) return Debug.WriteInfo(false, "UnixV6.Test: super-block free block count invalid (is {0:D0}, require 0 <= n <= 100)", n);
Int32 p = SB.GetUInt16L(bp); // SB[6] - free block chain next pointer
if ((p != 0) && ((p < isize + 2) || (p >= fsize))) return Debug.WriteInfo(false, "UnixV6.Test: super-block free chain pointer invalid (is {0:D0}, require {1:D0} <= n < {2:D0})", p, isize + 2, fsize);
for (Int32 i = 1; i < n; i++) // SB[8] - free block list
{
if (((p = SB.GetUInt16L(bp + 2 * i)) < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV6.Test: super-block free block {0:D0} invalid (is {1:D0}, require {2:D0} <= n < {3:D0})", i, p, isize + 2, fsize);
}
bp += 100 * 2;
n = SB.GetUInt16L(ref bp); // SB[206] - number of inodes in super-block free inode list
if (n > 100) return Debug.WriteInfo(false, "UnixV6.Test: super-block free i-node count invalid (is {0:D0}, require 0 <= n <= 100)", n);
for (Int32 i = 0; i < n; i++)
{
if (((p = SB.GetUInt16L(bp + 2 * i)) < 1) || (p > isize * INOPB)) return Debug.WriteInfo(false, "UnixV6.Test: super-block free i-number {0:D0} invalid (is {1:D0}, require 1 <= n < {2:D0})", i, p, isize * INOPB);
}
size = fsize;
type = typeof(UnixV6);
if (level == 2) return Debug.WriteInfo(true, "UnixV6.Test: file system size: {0:D0} blocks ({1:D0} i-nodes in blocks 2-{2:D0}, data in blocks {3:D0}-{4:D0}", fsize, isize * INOPB, isize + 1, isize + 2, fsize - 1);
// level 3 - check file headers (aka inodes) (return file system size and type)
Inode iNode;
for (UInt16 iNum = 1; iNum <= isize * INOPB; iNum++)
{
iNode = new InodeV6(volume, iNum);
if ((iNode.Type != ' ') && (iNode.nlinks == 0)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} is used but has zero link count", iNum);
//if ((iNode.Type == ' ') && (iNode.nlinks != 0)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} is free but has non-zero link count {1:D0}", iNum, iNode.nlinks);
// since iNode.size is a 24-bit number, the below test can't actually ever fail
if ((iNode.size < 0) || (iNode.size > 16777215)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} size invalid (is {1:D0}, require 0 <= n <= 16777215)", iNum, iNode.size);
if ((iNode.Type == ' ') && (iNode.size != 0)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} is free but has non-zero size {1:D0}", iNum, iNode.size);
if (((iNode.flags & 0x1000) == 0) && (iNode.size > 4096)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} size exceeds small file limit (is {1:D0}, require n <= 4096)", iNum, iNode.size);
if ((iNode.Type != '-') && (iNode.Type != 'd')) continue; // only check blocks for file and directory i-nodes
for (Int32 i = 0; i < 8; i++)
{
if ((p = iNode.addr[i]) == 0) continue;
if ((p < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} contains invalid block pointer (is {1:D0}, require {2:D0} <= n < {3:D0})", iNum, p, isize + 2, fsize);
if (p >= volume.BlockCount) return Debug.WriteInfo(false, "UnixV6.Test: volume too small to contain i-node {0:D0} {1} block {2:D0}", iNum, ((iNode.flags & 0x1000) == 0) ? "data" : "indirect", p);
if ((iNode.flags & 0x1000) != 0)
{
Block B = volume[p];
for (Int32 j = 0; j < 256; j++)
{
if ((p = B.GetUInt16L(2 * j)) == 0) continue;
if ((p < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} contains invalid block pointer (is {1:D0}, require {2:D0} <= n < {3:D0})", iNum, p, isize + 2, fsize);
if (p >= volume.BlockCount) return Debug.WriteInfo(false, "UnixV6.Test: volume too small to contain i-node {0:D0} {1} block {2:D0}", iNum, (i < 7) ? "data" : "indirect", p);
if (i == 7)
{
Block B2 = volume[p];
for (Int32 k = 0; k < 256; k++)
{
if ((p = B2.GetUInt16L(2 * k)) == 0) continue;
if ((p < isize + 2) || (p >= fsize)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} contains invalid block pointer (is {1:D0}, require {2:D0} <= n < {3:D0})", iNum, p, isize + 2, fsize);
if (p >= volume.BlockCount) return Debug.WriteInfo(false, "UnixV6.Test: volume too small to contain i-node {0:D0} data block {1:D0}", iNum, p);
}
}
}
}
}
}
if (level == 3) return true;
// level 4 - check directory structure (return file system size and type)
iNode = new InodeV6(volume, ROOT_INUM);
if (iNode.Type != 'd') return Debug.WriteInfo(false, "UnixV6.Test: root directory i-node mode invalid (is 0x{0:x4}, require 0xcnnn)", iNode.flags);
UInt16[] IMap = new UInt16[isize * INOPB + 1]; // inode usage map
Queue<Int32> DirList = new Queue<Int32>(); // queue of directories to examine
DirList.Enqueue((ROOT_INUM << 16) + ROOT_INUM); // parent inum in high word, directory inum in low word (root is its own parent)
while (DirList.Count != 0)
{
Int32 dNum = DirList.Dequeue();
Int32 pNum = dNum >> 16;
dNum &= 0xffff;
if (IMap[dNum] != 0) return Debug.WriteInfo(false, "UnixV6.Test: directory i-node {0:D0} appears more than once in directory structure", dNum);
IMap[dNum]++; // assume a link to this directory from its parent (root directory gets fixed later)
Byte[] buf = ReadFile(new InodeV6(volume, dNum), BLOCK_SIZE);
Boolean df = false;
Boolean ddf = false;
for (bp = 0; bp < buf.Length; bp += 16)
{
UInt16 iNum = Buffer.GetUInt16L(buf, bp);
if (iNum == 0) continue;
String name = Buffer.GetCString(buf, bp + 2, 14, Encoding.ASCII);
if (String.Compare(name, ".") == 0)
{
if (iNum != dNum) return Debug.WriteInfo(false, "UnixV6.Test: in directory i={0:D0}, entry \".\" does not refer to itself (is {1:D0}, require {2:D0})", dNum, iNum, dNum);
IMap[iNum]++;
df = true;
}
else if (String.Compare(name, "..") == 0)
{
if (iNum != pNum) return Debug.WriteInfo(false, "UnixV6.Test: in directory i={0:D0}, entry \"..\" does not refer to parent (is {1:D0}, require {2:D0})", dNum, iNum, pNum);
IMap[iNum]++;
ddf = true;
}
else if ((iNum < 2) || (iNum > isize * INOPB))
{
return Debug.WriteInfo(false, "UnixV6.Test: in directory i={0:D0}, entry \"{1}\" has invalid i-number (is {2:D0}, require 2 <= n <= {3:D0})", dNum, name, iNum, isize * INOPB);
}
else if ((iNode = new InodeV6(volume, iNum)).Type == 'd') // directory
{
DirList.Enqueue((dNum << 16) + iNum);
}
else // non-directory
{
IMap[iNum]++;
}
}
if (!df) return Debug.WriteInfo(false, "UnixV6.Test: in directory i={0:D0}, entry \".\" is missing", dNum);
if (!ddf) return Debug.WriteInfo(false, "UnixV6.Test: in directory i={0:D0}, entry \"..\" is missing", dNum);
}
IMap[ROOT_INUM]--; // root directory has no parent, so back out the assumed parent link
if (level == 4) return true;
// level 5 - check file header allocation (return file system size and type)
for (UInt16 iNum = 1; iNum <= isize * INOPB; iNum++)
{
iNode = new InodeV6(volume, iNum);
if ((iNode.Type == ' ') && (IMap[iNum] != 0)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} is free but has {1:D0} link(s)", iNum, IMap[iNum]);
if ((iNode.Type != ' ') && (IMap[iNum] == 0)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} is used but has no links", iNum);
if ((iNode.Type != ' ') && (IMap[iNum] != iNode.nlinks)) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} link count mismatch (is {1:D0}, expect {2:D0})", iNum, iNode.nlinks, IMap[iNum]);
}
// also check super-block free list
bp = 206;
n = SB.GetUInt16L(ref bp);
for (Int32 i = 0; i < n; i++)
{
UInt16 iNum = SB.GetUInt16L(ref bp);
if (IMap[iNum] != 0) return Debug.WriteInfo(false, "UnixV6.Test: i-node {0:D0} is in super-block free list, but has {1:D0} link(s)", iNum, IMap[iNum]);
}
if (level == 5) return true;
// level 6 - check data block allocation (return file system size and type)
UInt16[] BMap = new UInt16[fsize]; // block usage map
for (UInt16 iNum = 1; iNum <= isize * INOPB; iNum++)
{
iNode = new InodeV6(volume, iNum);
if ((iNode.Type != '-') && (iNode.Type != 'd')) continue; // only file and directory i-nodes have blocks allocated
n = (iNode.size + 511) / 512; // number of blocks required for file
// mark data blocks used
for (Int32 i = 0; i < n; i++)
{
if ((p = iNode[i]) == 0) continue;
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV6.Test: data block #{0:D0} ({1:D0}) of i-node {2:D0} is also allocated to i-node {3:D0}", i, p, iNum, BMap[p]);
BMap[p] = iNum;
}
if ((iNode.flags & 0x1000) == 0) continue; // small files have no indirect blocks
// mark indirect blocks used
for (Int32 i = 0; i < 8; i++)
{
if ((p = iNode.addr[i]) == 0) continue;
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV6.Test: indirect block {0:D0} of i-node {1:D0} is also allocated to i-node {2:D0}", p, iNum, BMap[p]);
BMap[p] = iNum;
if (i == 7)
{
// mark double-indirect blocks used
Block B = volume[p];
for (Int32 j = 0; j < 256; j++)
{
if ((p = B.GetUInt16L(2 * j)) == 0) continue;
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV6.Test: indirect block {0:D0} of i-node {1:D0} is also allocated to i-node {2:D0}", p, iNum, BMap[p]);
BMap[p] = iNum;
}
}
}
}
// mark used blocks with 1
for (Int32 i = 0; i < isize + 2; i++) BMap[i] = 1;
for (Int32 i = isize + 2; i < fsize; i++) if (BMap[i] != 0) BMap[i] = 1;
// mark free blocks with 2
bp = 4;
n = SB.GetUInt16L(ref bp); // number of blocks in super-block free block list
if ((p = SB.GetUInt16L(ref bp)) != 0) // free block chain next pointer
{
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV6.Test: list block {0:D0} in super-block free list is allocated", p);
BMap[p] = 2;
}
for (Int32 i = 1; i < n; i++)
{
Int32 q = SB.GetUInt16L(ref bp);
if (BMap[q] != 0) return Debug.WriteInfo(false, "UnixV6.Test: data block {0:D0} in super-block free list is allocated", q);
BMap[q] = 2;
}
// enumerate blocks in free block chain
while (p != 0)
{
Block B = volume[p];
bp = 0;
n = B.GetUInt16L(ref bp); // number of entries listed in this block
if ((p = B.GetUInt16L(ref bp)) != 0)
{
if (BMap[p] != 0) return Debug.WriteInfo(false, "UnixV6.Test: list block {0:D0} in free block chain is allocated", p);
BMap[p] = 2;