bool Skip(unsigned long long To);
bool Truncate(unsigned long long To);
unsigned long long Tell();
+ // the size of the file content (compressed files will be uncompressed first)
unsigned long long Size();
+ // the size of the file itself
unsigned long long FileSize();
time_t ModificationTime();
// check if the given file starts with a PGP cleartext signature
bool StartsWithGPGClearTextSignature(std::string const &FileName);
+/** change file attributes to requested known good values
+ *
+ * The method skips the user:group setting if not root.
+ *
+ * @param requester is printed as functionname in error cases
+ * @param file is the file to be modified
+ * @param user is the (new) owner of the file, e.g. _apt
+ * @param group is the (new) group owning the file, e.g. root
+ * @param mode is the access mode of the file, e.g. 0644
+ */
+bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode);
+
+/**
+ * \brief Drop privileges
+ *
+ * Drop the privileges to the user _apt (or the one specified in
+ * APT::Sandbox::User). This does not set the supplementary group
+ * ids up correctly, it only uses the default group. Also prevent
+ * the process from gaining any new privileges afterwards, at least
+ * on Linux.
+ *
+ * \return true on success, false on failure with _error set
+ */
+bool DropPrivileges();
+
// File string manipulators
std::string flNotDir(std::string File);
std::string flNotFile(std::string File);