shell/ash: use dup2() where possible, due to copyfd's inefficencies

1 files changed, 13 insertions, 1 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 7cc452d20..9f916b8a3 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -4875,13 +4875,21 @@ dupredirect(union node *redir, int f)
 
         if (redir->nfile.type == NTOFD || redir->nfile.type == NFROMFD) {
                 if (redir->ndup.dupfd >= 0) {   /* if not ">&-" */
+#ifdef __MINGW32__
+                        dup2(redir->ndup.dupfd, fd);
+#else
                         copyfd(redir->ndup.dupfd, fd);
+#endif
                 }
                 return;
         }
 
-        if (f != fd) {
+        if (f >= 0 && f != fd) {
+#ifdef __MINGW32__
+                dup2(f, fd);
+#else
                 copyfd(f, fd);
+#endif
                 close(f);
         }
 }
@@ -4978,7 +4986,11 @@ popredir(int drop)
                 if (rp->renamed[i] != EMPTY) {
                         if (!drop) {
                                 close(i);
+#ifdef __MINGW32__
+                                dup2(rp->renamed[i], i);
+#else
                                 copyfd(rp->renamed[i], i);
+#endif
                         }
                         close(rp->renamed[i]);
                 }