Adding upstream version 2.41.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

lib/exec_shell.c

@@ -0,0 +1,49 @@
+/*
+ * exec_shell() - launch a shell, else exit!
+ *
+ * This program 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 2, or (at your option) any
+ * later version.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <libgen.h>
+
+#include "nls.h"
+#include "c.h"
+#include "xalloc.h"
+
+#include "exec_shell.h"
+
+#define DEFAULT_SHELL "/bin/sh"
+
+void __attribute__((__noreturn__)) exec_shell(void)
+{
+	const char *shell = getenv("SHELL");
+	char *shellc;
+	const char *shell_basename;
+	char *arg0;
+
+	if (!shell)
+		shell = DEFAULT_SHELL;
+
+	shellc = xstrdup(shell);
+	shell_basename = basename(shellc);
+	xasprintf(&arg0, "-%s", shell_basename);
+
+	execl(shell, arg0, (char *)NULL);
+	errexec(shell);
+}