1 files changed, 82 insertions, 0 deletions
diff --git a/lib/shell.c b/lib/shell.c
new file mode 100644
index 0000000..25ef3e3
--- /dev/null
+++ b/lib/shell.c
@@ -0,0 +1,82 @@
+/*
+ * SPDX-FileCopyrightText: 1989 - 1991, Julianne Frances Haugh
+ * SPDX-FileCopyrightText: 1996 - 1998, Marek Michałkiewicz
+ * SPDX-FileCopyrightText: 2003 - 2006, Tomasz Kłoczko
+ * SPDX-FileCopyrightText: 2009       , Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ident "$Id$"
+
+#include <stdio.h>
+#include <errno.h>
+#include "prototypes.h"
+#include "defines.h"
+#include "string/sprintf.h"
+
+
+extern char **newenvp;
+extern size_t newenvc;
+
+/*
+ * shell - execute the named program
+ *
+ *	shell begins by trying to figure out what argv[0] is going to
+ *	be for the named process.  The user may pass in that argument,
+ *	or it will be the last pathname component of the file with a
+ *	'-' prepended.
+ *	Then, it executes the named file.
+ */
+
+int shell (const char *file, /*@null@*/const char *arg, char *const envp[])
+{
+	int   err;
+	char  arg0[1024];
+
+	if (file == NULL) {
+		errno = EINVAL;
+		return errno;
+	}
+
+	/*
+	 * The argv[0]'th entry is usually the path name, but
+	 * for various reasons the invoker may want to override
+	 * that.  So, we determine the 0'th entry only if they
+	 * don't want to tell us what it is themselves.
+	 */
+	if (arg == NULL) {
+		SNPRINTF(arg0, "-%s", Basename(file));
+		arg = arg0;
+	}
+
+	/*
+	 * First we try the direct approach.  The system should be
+	 * able to figure out what we are up to without too much
+	 * grief.
+	 */
+	(void) execle (file, arg, (char *) NULL, envp);
+	err = errno;
+
+	if (access (file, R_OK|X_OK) == 0) {
+		/*
+		 * Assume this is a shell script (with no shebang).
+		 * Interpret it with /bin/sh
+		 */
+		(void) execle (SHELL, "sh", "-", file, (char *) NULL, envp);
+		err = errno;
+	}
+
+	/*
+	 * Obviously something is really wrong - I can't figure out
+	 * how to execute this stupid shell, so I might as well give
+	 * up in disgust ...
+	 */
+	SNPRINTF(arg0, _("Cannot execute %s"), file);
+	errno = err;
+	perror (arg0);
+	return err;
+}
+