- add new applet rdev (Grant Erickson)

- fixes and shrink (me)

include/applets.h

@@ -286,6 +286,7 @@ USE_PSCAN(APPLET(pscan, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_PWD(APPLET_NOFORK(pwd, pwd, _BB_DIR_BIN, _BB_SUID_NEVER, pwd))
 USE_RAIDAUTORUN(APPLET(raidautorun, _BB_DIR_SBIN, _BB_SUID_NEVER))
 USE_RDATE(APPLET(rdate, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))
+USE_RDEV(APPLET(rdev, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))
 USE_READAHEAD(APPLET(readahead, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_READLINK(APPLET(readlink, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 USE_READPROFILE(APPLET(readprofile, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))

include/usage.h

@@ -3168,6 +3168,14 @@
      "\n	-s	Set the system date and time (default)" \
      "\n	-p	Print the date and time" \
 
+#define rdev_trivial_usage \
+       ""
+#define rdev_full_usage "\n\n" \
+       "Print the device node associated with the filesystem mounted at '/'"
+#define rdev_example_usage \
+       "$ rdev\n" \
+       "/dev/mtdblock9 /\n"
+
 #define readahead_trivial_usage \
        "[FILE]..."
 #define readahead_full_usage "\n\n" \

scripts/defconfig

@@ -520,6 +520,7 @@ CONFIG_FEATURE_MOUNT_FLAGS=y
 CONFIG_FEATURE_MOUNT_FSTAB=y
 CONFIG_PIVOT_ROOT=y
 CONFIG_RDATE=y
+CONFIG_RDEV=y
 CONFIG_READPROFILE=y
 CONFIG_RTCWAKE=y
 CONFIG_SCRIPT=y

util-linux/Config.in

@@ -707,6 +707,12 @@ config RDATE
 	  the RFC868 protocol, which is built into the inetd daemon on most
 	  systems.
 
+config RDEV
+       bool "rdev"
+       default n
+       help
+	  Print the device node associated with the filesystem mounted at '/'.
+
 config READPROFILE
 	bool "readprofile"
 	default n

util-linux/Kbuild

@@ -26,6 +26,7 @@ lib-$(CONFIG_MORE)              += more.o
 lib-$(CONFIG_MOUNT)             += mount.o
 lib-$(CONFIG_PIVOT_ROOT)        += pivot_root.o
 lib-$(CONFIG_RDATE)             += rdate.o
+lib-$(CONFIG_RDEV)              += rdev.o
 lib-$(CONFIG_READPROFILE)       += readprofile.o
 lib-$(CONFIG_RTCWAKE)           += rtcwake.o
 lib-$(CONFIG_SCRIPT)            += script.o

util-linux/rdev.c

@@ -0,0 +1,24 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * rdev - print device node associated with a filesystem
+ *
+ * Copyright (c) 2008 Nuovation System Designs, LLC
+ *   Grant Erickson <gerickson@nuovations.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ *
+ */
+
+#include "libbb.h"
+
+int rdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int rdev_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
+{
+	char const * const root_device = find_block_device("/");
+
+	if (root_device != NULL) {
+		printf("%s /\n", root_device);
+		return EXIT_SUCCESS;
+	}
+	return EXIT_FAILURE;
+}