* callproc.c (relocate_fd): Use F_DUPFD if defined.

1 files changed, 10 insertions, 4 deletions

diff --git a/src/callproc.c b/src/callproc.c
index e78d1a9aeaa..4ad6bcf41ea 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1288,7 +1288,16 @@ relocate_fd (int fd, int minfd)
     return fd;
   else
     {
-      int new = dup (fd);
+      int new;
+#ifdef F_DUPFD
+      new = fcntl (fd, F_DUPFD, minfd);
+#else
+      new = dup (fd);
+      if (new != -1)
+        /* Note that we hold the original FD open while we recurse,
+           to guarantee we'll get a new FD if we need it.  */
+        new = relocate_fd (new, minfd);
+#endif
       if (new == -1)
         {
           const char *message1 = "Error while setting up child: ";
@@ -1299,9 +1308,6 @@ relocate_fd (int fd, int minfd)
           emacs_write (2, message2, strlen (message2));
           _exit (1);
         }
-      /* Note that we hold the original FD open while we recurse,
-         to guarantee we'll get a new FD if we need it.  */
-      new = relocate_fd (new, minfd);
       emacs_close (fd);
       return new;
     }