Subject: [bug#75810] [PATCH v8 02/16] daemon: Close the read end of the logging pipe.

From: Ludovic Courtès <[email-masked]>
Date: Sun, 23 Mar 2025 15:24:55 +0100

* nix/libutil/util.cc (commonChildInit): Close ‘logPipe.readSide’.

Reported-by: Reepca Russelstein <[email-masked]>
Change-Id: Ia9e48d1afb85d7af52770e016f2b6832792044dd
---
 nix/libutil/util.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/nix/libutil/util.cc b/nix/libutil/util.cc
index eb2d16e1cc..56f116046c 100644
--- a/nix/libutil/util.cc
+++ b/nix/libutil/util.cc
@@ -1279,6 +1279,9 @@ void commonChildInit(Pipe & logPipe)
     if (setsid() == -1)
         throw SysError(format("creating a new session"));
 
+    /* Close the read end so only the parent holds a reference to it.  */
+    logPipe.readSide.close();
+
     /* Dup the write side of the logger pipe into stderr. */
     if (dup2(logPipe.writeSide, STDERR_FILENO) == -1)
         throw SysError("cannot pipe standard error into log file");
-- 
2.48.1