1 files changed, 117 insertions, 0 deletions
diff --git a/examples/loadables/push.c b/examples/loadables/push.c
new file mode 100644
index 0000000..b27455b
--- /dev/null
+++ b/examples/loadables/push.c
@@ -0,0 +1,117 @@
+/*
+ * push - anyone remember TOPS-20?
+ *
+ */
+
+/*
+   Copyright (C) 1999-2020 Free Software Foundation, Inc.
+
+   This file is part of GNU Bash.
+   Bash is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   Bash 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "builtins.h"
+#include "shell.h"
+#include "jobs.h"
+#include "bashgetopt.h"
+#include "common.h"
+
+#ifndef errno
+extern int errno;
+#endif
+
+extern pid_t dollar_dollar_pid;
+extern int last_command_exit_value;
+
+int
+push_builtin (list)
+     WORD_LIST *list;
+{
+  pid_t pid;
+  int xstatus, opt;
+
+  xstatus = EXECUTION_SUCCESS;
+  reset_internal_getopt ();
+  while ((opt = internal_getopt (list, "")) != -1)
+    {
+      switch (opt)
+	{
+	CASE_HELPOPT;
+	default:
+	  builtin_usage ();
+	  return (EX_USAGE);
+	}
+    }
+  list = loptend;  
+
+  pid = make_child (savestring ("push"), 0);
+  if (pid == -1)
+    {
+      builtin_error ("cannot fork: %s", strerror (errno));
+      return (EXECUTION_FAILURE);
+    }
+  else if (pid == 0)
+    {
+      /* Shell variable adjustments: $SHLVL, $$, $PPID, $! */
+      adjust_shell_level (1);
+      dollar_dollar_pid = getpid ();
+      set_ppid ();
+
+      /* Clean up job control stuff. */
+      stop_making_children ();
+      cleanup_the_pipeline ();
+      delete_all_jobs (0);
+
+      last_asynchronous_pid = NO_PID;
+
+      /* Make sure the job control code has the right values for
+	 the shell's process group and tty process group, and that
+	 the signals are set correctly for job control. */
+      initialize_job_control (0);
+      initialize_job_signals ();
+
+      /* And read commands until exit. */
+      reader_loop ();
+      exit_shell (last_command_exit_value);
+    }
+  else
+    {
+      stop_pipeline (0, (COMMAND *)NULL);
+      xstatus = wait_for (pid, 0);
+      return (xstatus);
+    }   
+}
+
+char *push_doc[] = {
+	"Create child shell.",
+	"",
+	"Create a child that is an exact duplicate of the running shell",
+	"and wait for it to exit.  The $SHLVL, $!, $$, and $PPID variables",
+	"are adjusted in the child.  The return value is the exit status",
+	"of the child.",
+	(char *)NULL
+};
+
+struct builtin push_struct = {
+	"push",
+	push_builtin,
+	BUILTIN_ENABLED,
+	push_doc,
+	"push",
+	0
+};