1 files changed, 70 insertions, 0 deletions
diff --git a/lib/spawn_faction_adddup2.c b/lib/spawn_faction_adddup2.c
new file mode 100644
index 0000000..8d257ae
--- /dev/null
+++ b/lib/spawn_faction_adddup2.c
@@ -0,0 +1,70 @@
+/* Copyright (C) 2000, 2009-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <spawn.h>
+
+#include <errno.h>
+#include <unistd.h>
+
+#if !_LIBC
+# define __sysconf(open_max) getdtablesize ()
+#endif
+
+#if REPLACE_POSIX_SPAWN
+# include "spawn_int.h"
+#endif
+
+/* Add an action to FILE-ACTIONS which tells the implementation to call
+   'dup2' for the given file descriptors during the 'spawn' call.  */
+int
+posix_spawn_file_actions_adddup2 (posix_spawn_file_actions_t *file_actions,
+                                  int fd, int newfd)
+#undef posix_spawn_file_actions_adddup2
+{
+  int maxfd = __sysconf (_SC_OPEN_MAX);
+
+  /* Test for the validity of the file descriptor.  */
+  if (fd < 0 || newfd < 0 || fd >= maxfd || newfd >= maxfd)
+    return EBADF;
+
+#if !REPLACE_POSIX_SPAWN
+  return posix_spawn_file_actions_adddup2 (file_actions, fd, newfd);
+#else
+  /* Allocate more memory if needed.  */
+  if (file_actions->_used == file_actions->_allocated
+      && __posix_spawn_file_actions_realloc (file_actions) != 0)
+    /* This can only mean we ran out of memory.  */
+    return ENOMEM;
+
+  {
+    struct __spawn_action *rec;
+
+    /* Add the new value.  */
+    rec = &file_actions->_actions[file_actions->_used];
+    rec->tag = spawn_do_dup2;
+    rec->action.dup2_action.fd = fd;
+    rec->action.dup2_action.newfd = newfd;
+
+    /* Account for the new entry.  */
+    ++file_actions->_used;
+
+    return 0;
+  }
+#endif
+}