Make NAR header check more robust

Changes

  std::bad_alloc

into

  bad archive: input doesn't look like a Nix archive

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 4b6ad5da5b9c..969e4dff383d 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -284,7 +284,7 @@ inline uint64_t readLongLong(Source & source)
 
 void readPadding(size_t len, Source & source);
 size_t readString(unsigned char * buf, size_t max, Source & source);
-string readString(Source & source);
+string readString(Source & source, size_t max = std::numeric_limits<size_t>::max());
 template<class T> T readStrings(Source & source);
 
 Source & operator >> (Source & in, string & s);