libutil, libstore: move closeExtraFDs to derivation goal

it's only used there.

Change-Id: I61ee47d37214c59c073cc9ed671ac1c82430227c

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

@@ -1199,6 +1199,52 @@ void LocalDerivationGoal::chownToBuilder(const AutoCloseFD & fd)
         throw SysError("cannot change ownership of file '%1%'", fd.guessOrInventPath());
 }
 
+static void closeExtraFDs()
+{
+    constexpr int MAX_KEPT_FD = 2;
+    static_assert(std::max({STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO}) == MAX_KEPT_FD);
+
+    // Both Linux and FreeBSD support close_range.
+#if __linux__ || __FreeBSD__
+    auto closeRange = [](unsigned int first, unsigned int last, int flags) -> int {
+    // musl does not have close_range as of 2024-08-10
+    // patch: https://www.openwall.com/lists/musl/2024/08/01/9
+#if HAVE_CLOSE_RANGE
+        return close_range(first, last, flags);
+#else
+        return syscall(SYS_close_range, first, last, flags);
+#endif
+    };
+    // first try to close_range everything we don't care about. if this
+    // returns an error with these parameters we're running on a kernel
+    // that does not implement close_range (i.e. pre 5.9) and fall back
+    // to the old method. we should remove that though, in some future.
+    if (closeRange(3, ~0U, 0) == 0) {
+        return;
+    }
+#endif
+
+#if __linux__
+    try {
+        for (auto & s : readDirectory("/proc/self/fd")) {
+            auto fd = std::stoi(s.name);
+            if (fd > MAX_KEPT_FD) {
+                debug("closing leaked FD %d", fd);
+                close(fd);
+            }
+        }
+        return;
+    } catch (SysError &) {
+    }
+#endif
+
+    int maxFD = 0;
+    maxFD = sysconf(_SC_OPEN_MAX);
+    for (int fd = MAX_KEPT_FD + 1; fd < maxFD; ++fd) {
+        close(fd); /* ignore result */
+    }
+}
+
 void LocalDerivationGoal::runChild(const Path & builder, const Strings & envStrs, const Strings & args)
 {
     /* Warning: in the child we should absolutely not make any SQLite

lix/libutil/file-descriptor.cc

@@ -268,52 +268,6 @@ void Pipe::close()
     writeSide.close();
 }
 
-
-void closeExtraFDs()
-{
-    constexpr int MAX_KEPT_FD = 2;
-    static_assert(std::max({STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO}) == MAX_KEPT_FD);
-
-    // Both Linux and FreeBSD support close_range.
-#if __linux__ || __FreeBSD__
-    auto closeRange = [](unsigned int first, unsigned int last, int flags) -> int {
-      // musl does not have close_range as of 2024-08-10
-      // patch: https://www.openwall.com/lists/musl/2024/08/01/9
-#if HAVE_CLOSE_RANGE
-        return close_range(first, last, flags);
-#else
-        return syscall(SYS_close_range, first, last, flags);
-#endif
-    };
-    // first try to close_range everything we don't care about. if this
-    // returns an error with these parameters we're running on a kernel
-    // that does not implement close_range (i.e. pre 5.9) and fall back
-    // to the old method. we should remove that though, in some future.
-    if (closeRange(3, ~0U, 0) == 0) {
-        return;
-    }
-#endif
-
-#if __linux__
-    try {
-        for (auto & s : readDirectory("/proc/self/fd")) {
-            auto fd = std::stoi(s.name);
-            if (fd > MAX_KEPT_FD) {
-                debug("closing leaked FD %d", fd);
-                close(fd);
-            }
-        }
-        return;
-    } catch (SysError &) {
-    }
-#endif
-
-    int maxFD = 0;
-    maxFD = sysconf(_SC_OPEN_MAX);
-    for (int fd = MAX_KEPT_FD + 1; fd < maxFD; ++fd)
-        close(fd); /* ignore result */
-}
-
 void closeOnExec(int fd, bool doClose)
 {
     int prev;

lix/libutil/file-descriptor.hh

@@ -101,12 +101,6 @@ private:
     SocketPair(AutoCloseFD a, AutoCloseFD b) : a(std::move(a)), b(std::move(b)) {}
 };
 
-/**
- * Close all file descriptors except stdio fds (ie 0, 1, 2).
- * Good practice in child processes.
- */
-void closeExtraFDs();
-
 /**
  * Set or clear the close-on-exec flag for the given file descriptor.
  */