5 files changed, 48 insertions, 0 deletions
diff --git a/src/libstore/build/child.cc b/src/libstore/build/child.cc
new file mode 100644
index 000000000..a82a5eec9
--- /dev/null
+++ b/src/libstore/build/child.cc
@@ -0,0 +1,33 @@
+#include "current-process.hh"
+#include "logging.hh"
+
+namespace nix {
+
+void commonChildInit()
+{
+    logger = makeSimpleLogger();
+
+    const static std::string pathNullDevice = "/dev/null";
+    restoreProcessContext(false);
+
+    /* Put the child in a separate session (and thus a separate
+       process group) so that it has no controlling terminal (meaning
+       that e.g. ssh cannot open /dev/tty) and it doesn't receive
+       terminal signals. */
+    if (setsid() == -1)
+        throw SysError("creating a new session");
+
+    /* Dup stderr to stdout. */
+    if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1)
+        throw SysError("cannot dup stderr into stdout");
+
+    /* Reroute stdin to /dev/null. */
+    int fdDevNull = open(pathNullDevice.c_str(), O_RDWR);
+    if (fdDevNull == -1)
+        throw SysError("cannot open '%1%'", pathNullDevice);
+    if (dup2(fdDevNull, STDIN_FILENO) == -1)
+        throw SysError("cannot dup null device into stdin");
+    close(fdDevNull);
+}
+
+}
diff --git a/src/libstore/build/child.hh b/src/libstore/build/child.hh
new file mode 100644
index 000000000..3dfc552b9
--- /dev/null
+++ b/src/libstore/build/child.hh
@@ -0,0 +1,11 @@
+#pragma once
+///@file
+
+namespace nix {
+
+/**
+ * Common initialisation performed in child processes.
+ */
+void commonChildInit();
+
+}
diff --git a/src/libstore/build/hook-instance.cc b/src/libstore/build/hook-instance.cc
index 108722cfb..86f72486e 100644
--- a/src/libstore/build/hook-instance.cc
+++ b/src/libstore/build/hook-instance.cc
@@ -1,3 +1,4 @@
+#include "child.hh"
 #include "file-system.hh"
 #include "globals.hh"
 #include "hook-instance.hh"
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index c90910d29..d385ffb34 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -14,6 +14,7 @@
 #include "cgroup.hh"
 #include "personality.hh"
 #include "namespaces.hh"
+#include "child.hh"
 
 #include <regex>
 #include <queue>
diff --git a/src/libstore/meson.build b/src/libstore/meson.build
index 98549f6d9..f776e9621 100644
--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@@ -79,6 +79,7 @@ libstore_sources = files(
   'store-api.cc',
   'uds-remote-store.cc',
   'worker-protocol.cc',
+  'build/child.cc',
   'build/derivation-goal.cc',
   'build/drv-output-substitution-goal.cc',
   'build/entry-points.cc',
@@ -96,6 +97,7 @@ libstore_sources = files(
 
 libstore_headers = files(
   'binary-cache-store.hh',
+  'build/child.hh',
   'build/derivation-goal.hh',
   'build/drv-output-substitution-goal.hh',
   'build/goal.hh',