From a47d8e13f0a092b8c574235ce14464e1d5441d9b Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Sun, 28 Jul 2019 21:33:05 +0100
Subject: [PATCH] Decode "SL" system area.

---
 DiscImageChef.Filesystems/ISO9660/Dir.cs      | 48 ++++++++++++++++++-
 DiscImageChef.Filesystems/ISO9660/File.cs     | 17 +++++++
 DiscImageChef.Filesystems/ISO9660/ISO9660.cs  |  7 ---
 .../ISO9660/Structs/Internal.cs               |  1 +
 4 files changed, 64 insertions(+), 9 deletions(-)

diff --git a/DiscImageChef.Filesystems/ISO9660/Dir.cs b/DiscImageChef.Filesystems/ISO9660/Dir.cs
index cb1865ad8..bc3308f72 100644
--- a/DiscImageChef.Filesystems/ISO9660/Dir.cs
+++ b/DiscImageChef.Filesystems/ISO9660/Dir.cs
@@ -248,6 +248,8 @@ namespace DiscImageChef.Filesystems.ISO9660
         {
             int systemAreaOff = start;
             hasResourceFork = false;
+            bool continueSymlink          = false;
+            bool continueSymlinkComponent = false;
 
             while(systemAreaOff + 2 <= end)
             {
@@ -459,10 +461,52 @@ namespace DiscImageChef.Filesystems.ISO9660
                         systemAreaOff += pnLength;
                         break;
                     case RRIP_SYMLINK:
-                        // TODO
                         byte slLength = data[systemAreaOff + 2];
-                        systemAreaOff += slLength;
 
+                        SymbolicLink sl =
+                            Marshal.ByteArrayToStructureLittleEndian<SymbolicLink>(data, systemAreaOff,
+                                                                                   Marshal.SizeOf<SymbolicLink>());
+
+                        SymbolicLinkComponent slc =
+                            Marshal.ByteArrayToStructureLittleEndian<SymbolicLinkComponent>(data,
+                                                                                            systemAreaOff +
+                                                                                            Marshal
+                                                                                               .SizeOf<SymbolicLink>(),
+                                                                                            Marshal
+                                                                                               .SizeOf<
+                                                                                                    SymbolicLinkComponent
+                                                                                                >());
+
+                        if(!continueSymlink || entry.SymbolicLink is null) entry.SymbolicLink = "";
+
+                        if(slc.flags.HasFlag(SymlinkComponentFlags.Root)) entry.SymbolicLink    =  "/";
+                        if(slc.flags.HasFlag(SymlinkComponentFlags.Current)) entry.SymbolicLink += ".";
+                        if(slc.flags.HasFlag(SymlinkComponentFlags.Parent)) entry.SymbolicLink  += "..";
+
+                        if(!continueSymlinkComponent && !slc.flags.HasFlag(SymlinkComponentFlags.Root))
+                            entry.SymbolicLink += "/";
+
+                        entry.SymbolicLink += slc.flags.HasFlag(SymlinkComponentFlags.Networkname)
+                                                  ? Environment.MachineName
+                                                  : joliet
+                                                      ? Encoding.BigEndianUnicode.GetString(data,
+                                                                                            systemAreaOff +
+                                                                                            Marshal
+                                                                                               .SizeOf<SymbolicLink>() +
+                                                                                            Marshal
+                                                                                               .SizeOf<
+                                                                                                    SymbolicLinkComponent
+                                                                                                >(), slc.length)
+                                                      : Encoding.GetString(data,
+                                                                           systemAreaOff                  +
+                                                                           Marshal.SizeOf<SymbolicLink>() +
+                                                                           Marshal.SizeOf<SymbolicLinkComponent>(),
+                                                                           slc.length);
+
+                        continueSymlink          = entry.Flags.HasFlag(SymlinkFlags.Continue);
+                        continueSymlinkComponent = entry.Flags.HasFlag(SymlinkComponentFlags.Continue);
+
+                        systemAreaOff += slLength;
                         break;
                     case RRIP_NAME:
                         byte nmLength = data[systemAreaOff + 2];
diff --git a/DiscImageChef.Filesystems/ISO9660/File.cs b/DiscImageChef.Filesystems/ISO9660/File.cs
index 081f1c14d..6b8430f8f 100644
--- a/DiscImageChef.Filesystems/ISO9660/File.cs
+++ b/DiscImageChef.Filesystems/ISO9660/File.cs
@@ -40,6 +40,7 @@ namespace DiscImageChef.Filesystems.ISO9660
             return Errno.NoError;
         }
 
+        // TODO: Resolve symbolic link
         public Errno Read(string path, long offset, long size, ref byte[] buf)
         {
             buf = null;
@@ -195,6 +196,8 @@ namespace DiscImageChef.Filesystems.ISO9660
 
             if(entry.RripBackup != null) stat.BackupTimeUtc = DecodeIsoDateTime(entry.RripBackup);
 
+            if(entry.SymbolicLink != null) stat.Attributes |= FileAttributes.Symlink;
+
             if(entry.AssociatedFile is null || entry.AssociatedFile.Extent == 0 || entry.AssociatedFile.Size == 0)
                 return Errno.NoError;
 
@@ -223,6 +226,20 @@ namespace DiscImageChef.Filesystems.ISO9660
             return Errno.NoError;
         }
 
+        public Errno ReadLink(string path, out string dest)
+        {
+            dest = null;
+
+            Errno err = GetFileEntry(path, out DecodedDirectoryEntry entry);
+            if(err != Errno.NoError) return err;
+
+            if(entry.SymbolicLink is null) return Errno.InvalidArgument;
+
+            dest = entry.SymbolicLink;
+
+            return Errno.NoError;
+        }
+
         Errno GetFileEntry(string path, out DecodedDirectoryEntry entry)
         {
             entry = null;
diff --git a/DiscImageChef.Filesystems/ISO9660/ISO9660.cs b/DiscImageChef.Filesystems/ISO9660/ISO9660.cs
index cd54d3312..45d6cd59a 100644
--- a/DiscImageChef.Filesystems/ISO9660/ISO9660.cs
+++ b/DiscImageChef.Filesystems/ISO9660/ISO9660.cs
@@ -71,13 +71,6 @@ namespace DiscImageChef.Filesystems.ISO9660
                 {"romeo", "Primary Volume Descriptor using the specified encoding codepage"}
             };
 
-        public Errno ReadLink(string path, out string dest)
-        {
-            dest = null;
-
-            return Errno.NotSupported;
-        }
-
         static Dictionary<string, string> GetDefaultOptions() =>
             new Dictionary<string, string> {{"debug", false.ToString()}};
     }
diff --git a/DiscImageChef.Filesystems/ISO9660/Structs/Internal.cs b/DiscImageChef.Filesystems/ISO9660/Structs/Internal.cs
index cb58fef37..5181e9c06 100644
--- a/DiscImageChef.Filesystems/ISO9660/Structs/Internal.cs
+++ b/DiscImageChef.Filesystems/ISO9660/Structs/Internal.cs
@@ -82,6 +82,7 @@ namespace DiscImageChef.Filesystems.ISO9660
             public byte[]                RripExpiration;
             public byte[]                RripModify;
             public uint                  Size;
+            public string                SymbolicLink;
             public DateTime?             Timestamp;
             public ushort                VolumeSequenceNumber;
             public CdromXa?              XA;