ensure Cnf::FindFile doesn't return files below /dev/null

Very unlikely, but if the parent is /dev/null, the child empty and the
grandchild a value we returned /dev/null/value which doesn't exist, so
hardly a problem, but for best operability we should be consistent in
our work and return /dev/null always.

1 files changed, 19 insertions, 0 deletions

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index e410f52d6..fa0930dff 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -694,6 +694,25 @@ string flAbsPath(string File)
    return AbsPath;
 }
 									/*}}}*/
+std::string flNormalize(std::string file)				/*{{{*/
+{
+   if (file.empty())
+      return file;
+   // do some normalisation by removing // and /./ from the path
+   size_t found = string::npos;
+   while ((found = file.find("/./")) != string::npos)
+      file.replace(found, 3, "/");
+   while ((found = file.find("//")) != string::npos)
+      file.replace(found, 2, "/");
+
+   if (APT::String::Startswith(file, "/dev/null"))
+   {
+      file.erase(strlen("/dev/null"));
+      return file;
+   }
+   return file;
+}
+									/*}}}*/
 // SetCloseExec - Set the close on exec flag				/*{{{*/
 // ---------------------------------------------------------------------
 /* */