Remove bad daemon connections from the pool

This is necessary for long-running processes like hydra-queue-runner:
if a nix-daemon worker is killed, we need to stop reusing that
connection.

1 files changed, 19 insertions, 3 deletions

diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index f136a13248..c9620e2bf3 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -72,7 +72,17 @@ void FdSink::write(const unsigned char * data, size_t len)
             warned = true;
         }
     }
-    writeFull(fd, data, len);
+    try {
+        writeFull(fd, data, len);
+    } catch (SysError & e) {
+        _good = true;
+    }
+}
+
+
+bool FdSink::good()
+{
+    return _good;
 }
 
 
@@ -119,12 +129,18 @@ size_t FdSource::readUnbuffered(unsigned char * data, size_t len)
         checkInterrupt();
         n = ::read(fd, (char *) data, bufSize);
     } while (n == -1 && errno == EINTR);
-    if (n == -1) throw SysError("reading from file");
-    if (n == 0) throw EndOfFile("unexpected end-of-file");
+    if (n == -1) { _good = false; throw SysError("reading from file"); }
+    if (n == 0) { _good = false; throw EndOfFile("unexpected end-of-file"); }
     return n;
 }
 
 
+bool FdSource::good()
+{
+    return _good;
+}
+
+
 size_t StringSource::read(unsigned char * data, size_t len)
 {
     if (pos == s.size()) throw EndOfFile("end of string reached");