try seeking on fds opened with OpenDescriptor before giving up

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index 44486905f8a204a9012c9c8b9435e5318031acd3..a98c2cb855e4271257032a15dc6571d61bc7a029 100644 (file)
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -1154,12 +1154,19 @@ bool FileFd::Seek(unsigned long long To)
       if ((d->openmode & ReadOnly) != ReadOnly)
         return _error->Error("Reopen is only implemented for read-only files!");
       close(iFd);
+      iFd = 0;
       if (TemporaryFileName.empty() == false)
         iFd = open(TemporaryFileName.c_str(), O_RDONLY);
       else if (FileName.empty() == false)
         iFd = open(FileName.c_str(), O_RDONLY);
       else
-        return _error->Error("Reopen is not implemented for OpenDescriptor()-FileFd!");
+      {
+        if (d->compressed_fd > 0)
+           if (lseek(d->compressed_fd, 0, SEEK_SET) != 0)
+              iFd = d->compressed_fd;
+        if (iFd <= 0)
+           return _error->Error("Reopen is not implemented for pipes opened with FileFd::OpenDescriptor()!");
+      }
 
       if (OpenInternDescriptor(d->openmode, d->compressor) == false)
         return _error->Error("Seek on file %s because it couldn't be reopened", FileName.c_str());