3 files changed, 51 insertions, 3 deletions
diff --git a/apt-pkg/contrib/cdromutl.cc b/apt-pkg/contrib/cdromutl.cc
index 6dce82fe1..68b980407 100644
--- a/apt-pkg/contrib/cdromutl.cc
+++ b/apt-pkg/contrib/cdromutl.cc
@@ -156,6 +156,19 @@ bool MountCdrom(string Path, string DeviceName)
 bool IdentCdrom(string CD,string &Res,unsigned int Version)
 {
    MD5Summation Hash;
+   bool writable_media = false;
+
+   // if we are on a writable medium (like a usb-stick) that is just
+   // used like a cdrom don't use "." as it will constantly change,
+   // use .disk instead
+   if (access(CD.c_str(), W_OK) == 0 && DirectoryExists(CD+string("/.disk"))) 
+   {
+      writable_media = true;
+      CD = CD.append("/.disk");
+      if (_config->FindB("Debug::aptcdrom",false) == true)
+         std::clog << "Found writable cdrom, using alternative path: " << CD
+                   << std::endl;
+   }
 
    string StartDir = SafeGetCWD();
    if (chdir(CD.c_str()) != 0)
@@ -202,10 +215,15 @@ bool IdentCdrom(string CD,string &Res,unsigned int Version)
       struct statvfs Buf;
       if (statvfs(CD.c_str(),&Buf) != 0)
 	 return _error->Errno("statfs",_("Failed to stat the cdrom"));
-      
+
       // We use a kilobyte block size to advoid overflow
-      sprintf(S,"%lu %lu",(long)(Buf.f_blocks*(Buf.f_bsize/1024)),
-	      (long)(Buf.f_bfree*(Buf.f_bsize/1024)));
+      if (writable_media)
+      {
+         sprintf(S,"%lu",(long)(Buf.f_blocks*(Buf.f_bsize/1024)));
+      } else {
+         sprintf(S,"%lu %lu",(long)(Buf.f_blocks*(Buf.f_bsize/1024)),
+                 (long)(Buf.f_bfree*(Buf.f_bsize/1024)));
+      }
       Hash.Add(S);
       sprintf(S,"-%u",Version);
    }
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index 2b73d1424..eabaadf90 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -251,6 +251,27 @@ bool CreateDirectory(string const &Parent, string const &Path)
    return true;
 }
 									/*}}}*/
+// CreateAPTDirectoryIfNeeded - ensure that the given directory exists		/*{{{*/
+// ---------------------------------------------------------------------
+/* a small wrapper around CreateDirectory to check if it exists and to
+   remove the trailing "/apt/" from the parent directory if needed */
+bool CreateAPTDirectoryIfNeeded(string const &Parent, string const &Path)
+{
+   if (DirectoryExists(Path) == true)
+      return true;
+
+   size_t const len = Parent.size();
+   if (len > 5 && Parent.find("/apt/", len - 6, 5) == len - 5)
+   {
+      if (CreateDirectory(Parent.substr(0,len-5), Path) == true)
+	 return true;
+   }
+   else if (CreateDirectory(Parent, Path) == true)
+      return true;
+
+   return false;
+}
+									/*}}}*/
 // GetListOfFilesInDir - returns a vector of files in the given dir	/*{{{*/
 // ---------------------------------------------------------------------
 /* If an extension is given only files with this extension are included
diff --git a/apt-pkg/contrib/fileutl.h b/apt-pkg/contrib/fileutl.h
index cb4655798..419506273 100644
--- a/apt-pkg/contrib/fileutl.h
+++ b/apt-pkg/contrib/fileutl.h
@@ -94,6 +94,15 @@ int GetLock(string File,bool Errors = true);
 bool FileExists(string File);
 bool DirectoryExists(string const &Path) __attrib_const;
 bool CreateDirectory(string const &Parent, string const &Path);
+
+/** \brief Ensure the existence of the given Path
+ *
+ *  \param Parent directory of the Path directory - a trailing
+ *  /apt/ will be removed before CreateDirectory call.
+ *  \param Path which should exist after (successful) call
+ */
+bool CreateAPTDirectoryIfNeeded(string const &Parent, string const &Path);
+
 std::vector<string> GetListOfFilesInDir(string const &Dir, string const &Ext,
 					bool const &SortList, bool const &AllowNoExt=false);
 std::vector<string> GetListOfFilesInDir(string const &Dir, std::vector<string> const &Ext,