drop privileges in copy:// method as we do for file://

Continueing on the track of dropping privileges in all methods, lets
drop it in copy, too, as the reasoning for it is very similar to file
and the interaction between the too quiet interesting as copy kinda
surfed as a fallback for file not being able to read the file. Both now
show a better error message as well as it was previously claiming to
have a hashsum mismatch, given that it couldn't read the file.

Git-Dch: Ignore

1 files changed, 37 insertions, 0 deletions

diff --git a/methods/aptmethod.h b/methods/aptmethod.h
new file mode 100644
index 000000000..61d7b78f1
--- /dev/null
+++ b/methods/aptmethod.h
@@ -0,0 +1,37 @@
+#ifndef APT_APTMETHOD_H
+#define APT_APTMETHOD_H
+
+#include <apt-pkg/acquire-method.h>
+
+#include <string>
+
+class aptMethod : public pkgAcqMethod
+{
+   char const * const Binary;
+   public:
+   virtual bool Configuration(std::string Message) APT_OVERRIDE;
+
+   bool CalculateHashes(FetchItem const * const Itm, FetchResult &Res) const;
+
+   aptMethod(char const * const Binary, char const * const Ver, unsigned long const Flags) : pkgAcqMethod(Ver, Flags), Binary(Binary) {};
+};
+bool aptMethod::Configuration(std::string Message)
+{
+   if (pkgAcqMethod::Configuration(Message) == false)
+      return false;
+
+   DropPrivsOrDie();
+
+   return true;
+}
+bool aptMethod::CalculateHashes(FetchItem const * const Itm, FetchResult &Res) const
+{
+   Hashes Hash(Itm->ExpectedHashes);
+   FileFd Fd;
+   if (Fd.Open(Res.Filename, FileFd::ReadOnly) == false || Hash.AddFD(Fd) == false)
+      return false;
+   Res.TakeHashes(Hash);
+   return true;
+}
+
+#endif