jn: new applet

Add a Windows-specific applet to create a directory junction.

Usage:  jn DIR JUNC

where DIR must be an existing directory on a local drive and JUNC
must not currently exist.

There isn't a simple WIN32 API to create directory junctions.
The implementation of mklink in ReactOS provided useful inspiration.

1 files changed, 37 insertions, 0 deletions

diff --git a/miscutils/jn.c b/miscutils/jn.c
new file mode 100644
index 000000000..db6a3e6d9
--- /dev/null
+++ b/miscutils/jn.c
@@ -0,0 +1,37 @@
+/*
+ * directory junction creation for busybox
+ *
+ * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
+ * Copyright (C) 2022 Ron Yorston <rmy@pobox.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+//config:config JN
+//config:       bool "jn (3.2 kb)"
+//config:       default y
+//config:       depends on PLATFORM_MINGW32
+//config:       help
+//config:       Creates a directory junction.
+
+//applet:IF_JN(APPLET_NOEXEC(jn, jn, BB_DIR_USR_BIN, BB_SUID_DROP, jn))
+
+//kbuild:lib-$(CONFIG_JN) += jn.o
+
+//usage:#define jn_trivial_usage
+//usage:       "DIR JUNC"
+//usage:#define jn_full_usage "\n\n"
+//usage:       "Create directory junction JUNC to DIR"
+
+#include "libbb.h"
+
+int jn_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int jn_main(int argc UNUSED_PARAM, char **argv)
+{
+        getopt32(argv, "^" "" "\0" "=2");
+        argv += optind;
+        if (create_junction(argv[0], argv[1]) != 0) {
+                bb_perror_msg_and_die("can't create junction '%s' to '%s'",
+                        argv[1], argv[0]);
+        }
+        return EXIT_SUCCESS;
+}