libstore: inline commonExecveingChildInit into single user

Change-Id: Ia389ec8c5e375b8386949c5fb031a52f27e76d37

lix/libstore/build/child.cc

@@ -1,35 +0,0 @@
-#include "lix/libutil/c-calls.hh"
-#include "lix/libutil/current-process.hh"
-#include "lix/libutil/logging.hh"
-
-namespace nix {
-
-void commonExecveingChildInit()
-{
-    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. */
-    auto fdDevNull = sys::open(pathNullDevice, O_RDWR);
-    if (!fdDevNull) {
-        throw SysError("cannot open '%1%'", pathNullDevice);
-    }
-    if (dup2(fdDevNull.get(), STDIN_FILENO) == -1) {
-        throw SysError("cannot dup null device into stdin");
-    }
-}
-
-}

lix/libstore/build/child.hh

@@ -1,15 +0,0 @@
-#pragma once
-///@file
-
-namespace nix {
-
-/**
- * Common initialisation performed in child processes that are just going to
- * execve.
- *
- * These processes may not use ReceiveInterrupts as they do not have an
- * interrupt receiving thread.
- */
-void commonExecveingChildInit();
-
-}

lix/libstore/build/hook-instance.cc

@@ -1,4 +1,3 @@
-#include "lix/libstore/build/child.hh"
 #include "lix/libutil/c-calls.hh"
 #include "lix/libutil/error.hh"
 #include "lix/libutil/file-descriptor.hh"

lix/libstore/build/local-derivation-goal.cc

@@ -2,6 +2,7 @@
 #include "derivation-goal.hh"
 #include "lix/libutil/async-io.hh"
 #include "lix/libutil/async.hh"
+#include "lix/libutil/current-process.hh"
 #include "lix/libutil/error.hh"
 #include "lix/libstore/indirect-root-store.hh"
 #include "lix/libstore/machines.hh"
@@ -25,7 +26,6 @@
 #include "lix/libutil/json.hh"
 #include "lix/libstore/build/personality.hh"
 #include "lix/libutil/namespaces.hh"
-#include "lix/libstore/build/child.hh"
 #include "lix/libutil/types.hh"
 #include "lix/libutil/unix-domain-socket.hh"
 #include "lix/libutil/mount.hh"
@@ -1208,7 +1208,31 @@ void LocalDerivationGoal::runChild(const Path & builder, const Strings & envStrs
 
     try { /* child */
 
-        commonExecveingChildInit();
+        logger = makeSimpleLogger();
+
+        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. */
+        AutoCloseFD fdDevNull{open("/dev/null", O_RDWR)};
+        if (!fdDevNull) {
+            throw SysError("cannot open '%1%'", "/dev/null");
+        }
+        if (dup2(fdDevNull.get(), STDIN_FILENO) == -1) {
+            throw SysError("cannot dup null device into stdin");
+        }
 
         const bool setUser = prepareChildSetup();
 

lix/libstore/meson.build

@@ -174,7 +174,6 @@ liblix_sources += files(
   # keep-sorted start
   'binary-cache-store.cc',
   'build-result.cc',
-  'build/child.cc',
   'build/derivation-goal.cc',
   'build/entry-points.cc',
   'build/goal.cc',
@@ -242,7 +241,6 @@ libstore_headers = files(
   # keep-sorted start
   'binary-cache-store.hh',
   'build-result.hh',
-  'build/child.hh',
   'build/derivation-goal.hh',
   'build/goal.hh',
   'build/hook-instance.hh',