build-remote: Ugly hackery to get build logs to work

The build hook mechanism expects build log output to go to file
descriptor 4, so do that.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 1f6ea4dc1c..a6479a450e 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -17,6 +17,9 @@ struct LegacySSHStore : public Store
     const Setting<Path> sshKey{this, "", "ssh-key", "path to an SSH private key"};
     const Setting<bool> compress{this, false, "compress", "whether to compress the connection"};
 
+    // Hack for getting remote build log output.
+    const Setting<int> logFD{this, -1, "log-fd", "file descriptor to which SSH's stderr is connected"};
+
     struct Connection
     {
         std::unique_ptr<SSHMaster::Connection> sshConn;
@@ -44,7 +47,8 @@ struct LegacySSHStore : public Store
             sshKey,
             // Use SSH master only if using more than 1 connection.
             connections->capacity() > 1,
-            compress)
+            compress,
+            logFD)
     {
     }