flash_lock, flash_unlock: new applets

By Thierry Reding (thierry.reding AT avionic-design.de)

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

miscutils/flash_lock_unlock.c

@@ -0,0 +1,69 @@
+/* vi: set sw=4 ts=4: */
+/* Ported to busybox from mtd-utils.
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+#include "libbb.h"
+#include <mtd/mtd-user.h>
+
+int flash_lock_unlock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int flash_lock_unlock_main(int argc UNUSED_PARAM, char **argv)
+{
+	/* note: fields in these structs are 32-bits.
+	 * apparently we can't win anything by using off_t
+	 * or long long's for offset and/or sectors vars. */
+	struct mtd_info_user info;
+	struct erase_info_user lock;
+	unsigned long offset;
+	long sectors;
+	int fd;
+
+#define do_lock (ENABLE_FLASH_LOCK && (!ENABLE_FLASH_UNLOCK || (applet_name[6] == 'l')))
+
+	if (!argv[1])
+		bb_show_usage();
+
+	/* parse offset and number of sectors to lock */
+	offset = 0;
+	sectors = -1;
+	if (do_lock) {
+		if (!argv[2] || !argv[3])
+			bb_show_usage();
+		offset = xstrtoul(argv[2], 0);
+		sectors = xstrtol(argv[3], 0);
+	}
+
+	fd = xopen(argv[1], O_RDWR);
+
+	xioctl(fd, MEMGETINFO, &info);
+
+	lock.start = 0;
+	lock.length = info.size;
+	if (do_lock) {
+		unsigned long size = info.size - info.erasesize;
+		if (offset > size) {
+			bb_error_msg_and_die("%lx is beyond device size %lx\n",
+					offset, size);
+		}
+
+		if (sectors == -1) {
+			sectors = info.size / info.erasesize;
+		} else {
+// isn't this useless?
+			unsigned long num = info.size / info.erasesize;
+			if (sectors > num) {
+				bb_error_msg_and_die("%ld are too many "
+						"sectors, device only has "
+						"%ld\n", sectors, num);
+			}
+		}
+
+		lock.start = offset;
+		lock.length = sectors * info.erasesize;
+		xioctl(fd, MEMLOCK, &lock);
+	} else {
+		xioctl(fd, MEMUNLOCK, &lock);
+	}
+
+	return EXIT_SUCCESS;
+}