improve error reporting in case of errors in combination with zlib

apt-pkg/contrib/fileutl.cc

@@ -867,6 +867,7 @@ bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Co
    else
       iFd = open(FileName.c_str(), fileflags, Perms);
 
+   this->FileName = FileName;
    if (iFd == -1 || OpenInternDescriptor(Mode, compressor) == false)
    {
       if (iFd != -1)
@@ -877,7 +878,6 @@ bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Co
       return _error->Errno("open",_("Could not open file %s"), FileName.c_str());
    }
 
-   this->FileName = FileName;
    SetCloseExec(iFd,true);
    return true;
 }
@@ -916,13 +916,13 @@ bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, APT::Configuration:
    d->openmode = Mode;
    Flags = (AutoClose) ? FileFd::AutoClose : 0;
    iFd = Fd;
+   this->FileName = "";
    if (OpenInternDescriptor(Mode, compressor) == false)
    {
       if (AutoClose)
 	 close (iFd);
       return _error->Errno("gzdopen",_("Could not open file descriptor %d"), Fd);
    }
-   this->FileName = "";
    return true;
 }
 bool FileFd::OpenInternDescriptor(unsigned int const Mode, APT::Configuration::Compressor const &compressor)
@@ -1057,11 +1057,21 @@ bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
       else
 #endif
          Res = read(iFd,To,Size);
-      if (Res < 0 && errno == EINTR)
-	 continue;
+
       if (Res < 0)
       {
+	 if (errno == EINTR)
+	    continue;
 	 Flags |= Fail;
+#if APT_USE_ZLIB
+	 if (d->gz != NULL)
+	 {
+	    int err;
+	    char const * const errmsg = gzerror(d->gz, &err);
+	    if (err != Z_ERRNO)
+	       return _error->Error("gzread: %s (%d: %s)", _("Read error"), err, errmsg);
+	 }
+#endif
 	 return _error->Errno("read",_("Read error"));
       }
       
@@ -1405,7 +1415,7 @@ bool FileFd::Close()
 #if APT_USE_ZLIB
       if (d != NULL && d->gz != NULL) {
 	 int const e = gzclose(d->gz);
-	 // gzdopen() on empty files always fails with "buffer error" here, ignore that
+	 // gzdclose() on empty files always fails with "buffer error" here, ignore that
 	 if (e != 0 && e != Z_BUF_ERROR)
 	    Res &= _error->Errno("close",_("Problem closing the gzip file %s"), FileName.c_str());
       } else

apt-pkg/contrib/mmap.cc

@@ -85,7 +85,7 @@ bool MMap::Map(FileFd &Fd)
 	 return _error->Error("Compressed file %s can only be mapped readonly", Fd.Name().c_str());
       Base = new unsigned char[iSize];
       if (Fd.Seek(0L) == false || Fd.Read(Base, iSize) == false)
-	 return false;
+	 return _error->Error("Compressed file %s can't be read into mmap", Fd.Name().c_str());
       return true;
    }