/*
 * mtd - simple memory technology device manipulation tool
 *
 * Copyright (c) 2006, 2007 Thorsten Glaser <tg@freewrt.org>
 * Copyright (C) 2005 Waldemar Brodkorb <wbx@freewrt.org>,
 *	                  Felix Fietkau <nbd@openwrt.org>
 *
 * 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
 * of the License, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * The code is based on the linux-mtd examples.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <limits.h>
#include <unistd.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <fcntl.h>
#include <errno.h>
#include <error.h>
#include <err.h>
#include <time.h>
#include <string.h>

#include <mtd/mtd-user.h>
#include <linux/reboot.h>

#define BUFSIZE (16 * 1024)
#define MAX_ARGS 8

#define DEBUG

int mtd_check(char *);
int mtd_unlock(const char *);
int mtd_open(const char *, int);
int mtd_erase(const char *);
int mtd_write(int, const char *, int, bool);
void usage(void) __attribute__((noreturn));

char buf[BUFSIZE];
int buflen;

int
mtd_check(char *mtd)
{
	struct mtd_info_user mtdInfo;
	int fd;

	fd = mtd_open(mtd, O_RDWR | O_SYNC);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		return 0;
	}

	if(ioctl(fd, MEMGETINFO, &mtdInfo)) {
		fprintf(stderr, "Could not get MTD device info from %s\n", mtd);
		close(fd);
		return 0;
	}

	close(fd);
	return 1;
}

int
mtd_unlock(const char *mtd)
{
	int fd;
	struct mtd_info_user mtdInfo;
	struct erase_info_user mtdLockInfo;

	fd = mtd_open(mtd, O_RDWR | O_SYNC);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		exit(1);
	}

	if(ioctl(fd, MEMGETINFO, &mtdInfo)) {
		fprintf(stderr, "Could not get MTD device info from %s\n", mtd);
		close(fd);
		exit(1);
	}

	mtdLockInfo.start = 0;
	mtdLockInfo.length = mtdInfo.size;
	if(ioctl(fd, MEMUNLOCK, &mtdLockInfo)) {
		close(fd);
		return 0;
	}

	close(fd);
	return 0;
}

int
mtd_open(const char *mtd, int flags)
{
	FILE *fp;
	char dev[PATH_MAX];
	int i;

	if ((fp = fopen("/proc/mtd", "r"))) {
		while (fgets(dev, sizeof(dev), fp)) {
			if (sscanf(dev, "mtd%d:", &i) && strstr(dev, mtd)) {
				snprintf(dev, sizeof(dev), "/dev/mtd%d", i);
				fclose(fp);
				return open(dev, flags);
			}
		}
		fclose(fp);
	}

	return open(mtd, flags);
}

int
mtd_erase(const char *mtd)
{
	int fd;
	struct mtd_info_user mtdInfo;
	struct erase_info_user mtdEraseInfo;

	fd = mtd_open(mtd, O_RDWR | O_SYNC);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		exit(1);
	}

	if(ioctl(fd, MEMGETINFO, &mtdInfo)) {
		fprintf(stderr, "Could not get MTD device info from %s\n", mtd);
		close(fd);
		exit(1);
	}

	mtdEraseInfo.length = mtdInfo.erasesize;

	for (mtdEraseInfo.start = 0;
		 mtdEraseInfo.start < mtdInfo.size;
		 mtdEraseInfo.start += mtdInfo.erasesize) {

		ioctl(fd, MEMUNLOCK, &mtdEraseInfo);
		if(ioctl(fd, MEMERASE, &mtdEraseInfo)) {
			fprintf(stderr, "Could not erase MTD device: %s\n", mtd);
			close(fd);
			exit(1);
		}
	}

	close(fd);
	return 0;

}

int
mtd_write(int imagefd, const char *mtd, int quiet, bool do_erase)
{
	int fd, result;
	size_t r, w, e;
	struct mtd_info_user mtdInfo;
	struct erase_info_user mtdEraseInfo;

	fd = mtd_open(mtd, O_RDWR | O_SYNC);
	if(fd < 0) {
		fprintf(stderr, "Could not open mtd device: %s\n", mtd);
		exit(1);
	}

	if(ioctl(fd, MEMGETINFO, &mtdInfo)) {
		fprintf(stderr, "Could not get MTD device info from %s\n", mtd);
		close(fd);
		exit(1);
	}

	r = w = e = 0;
	if (!quiet)
		fprintf(stderr, " [ ]");

	for (;;) {
		/* buffer may contain data already (from trx check) */
		r = buflen;
		r += read(imagefd, buf + buflen, BUFSIZE - buflen);
		w += r;

		/* EOF */
		if (r <= 0) break;

		/* need to erase the next block before writing data to it */
		while (do_erase && w > e) {
			mtdEraseInfo.start = e;
			mtdEraseInfo.length = mtdInfo.erasesize;

			if (!quiet)
				fprintf(stderr, "\b\b\b[e]");
			/* erase the chunk */
			if (ioctl (fd,MEMERASE,&mtdEraseInfo) < 0) {
				fprintf(stderr, "Erasing mtd failed: %s\n", mtd);
				exit(1);
			}
			e += mtdInfo.erasesize;
		}

		if (!quiet)
			fprintf(stderr, "\b\b\b[w]");

		if ((result = write(fd, buf, r)) < (ssize_t)r) {
			if (result < 0) {
				fprintf(stderr, "Error writing image.\n");
				exit(1);
			} else {
				fprintf(stderr, "Insufficient space.\n");
				exit(1);
			}
		}

		buflen = 0;
	}
	if (!quiet)
		fprintf(stderr, "\b\b\b\b");

	close(fd);
	return 0;
}

void
usage(void)
{
	fprintf(stderr, "Usage: mtd [<options> ...] <command> [<arguments> ...] <device>\n\n"
	"The device is in the format of mtdX (eg: mtd4) or its label.\n"
	"mtd recognises these commands:\n"
	"        unlock                  unlock the device\n"
	"        erase                   erase all data on device\n"
	"        write <imagefile>|-     write <imagefile> (use - for stdin) to device\n"
	"Following options are available:\n"
	"        -q                      quiet mode (once: no [w] on writing,\n"
	"                                           twice: no status messages)\n"
	"        -e <device>             erase <device> before executing the command\n\n"
	"        -r                      reboot after successful command\n"
	"Example: To write linux.img to mtd partition labeled as linux\n"
	"         mtd write linux.img linux\n\n");
	exit(1);
}

int
main(int argc, char **argv)
{
	int ch, i, imagefd = -1, quiet, unlocked, boot;
	char *erase[MAX_ARGS], *device;
	const char *imagefile = NULL;
	enum {
		CMD_ERASE,
		CMD_WRITE,
		CMD_UNLOCK
	} cmd;

	erase[0] = NULL;
	boot = 0;
	buflen = 0;
	quiet = 0;

	while ((ch = getopt(argc, argv, "Fqre:")) != -1)
		switch (ch) {
			case 'F':
				quiet = 1;
				/* FALLTHROUGH */
			case 'q':
				quiet++;
				break;
			case 'r':
				boot = 1;
				break;
			case 'e':
				i = 0;
				while ((erase[i] != NULL) && ((i + 1) < MAX_ARGS))
					i++;

				erase[i++] = optarg;
				erase[i] = NULL;
				break;

			case '?':
			default:
				usage();
		}
	argc -= optind;
	argv += optind;

	if (argc < 2)
		usage();

	if ((strcmp(argv[0], "unlock") == 0) && (argc == 2)) {
		cmd = CMD_UNLOCK;
		device = argv[1];
	} else if ((strcmp(argv[0], "erase") == 0) && (argc == 2)) {
		cmd = CMD_ERASE;
		device = argv[1];
	} else if ((strcmp(argv[0], "write") == 0) && (argc == 3)) {
		cmd = CMD_WRITE;
		device = argv[2];

		if (strcmp(argv[1], "-") == 0) {
			imagefile = "<stdin>";
			imagefd = 0;
		} else {
			imagefile = argv[1];
			if ((imagefd = open(argv[1], O_RDONLY)) < 0) {
				fprintf(stderr, "Couldn't open image file: %s!\n", imagefile);
				exit(1);
			}
		}

		if (!mtd_check(device)) {
			fprintf(stderr, "Can't open device for writing!\n");
			exit(1);
		}
	} else {
		usage();
	}

	sync();

	i = 0;
	unlocked = 0;
	while (erase[i] != NULL) {
		if (quiet < 2)
			fprintf(stderr, "Unlocking %s ...\n", erase[i]);
		mtd_unlock(erase[i]);
		if (quiet < 2)
			fprintf(stderr, "Erasing %s ...\n", erase[i]);
		mtd_erase(erase[i]);
		if (strcmp(erase[i], device) == 0)
			/* this means that <device> is unlocked and erased */
			unlocked = 1;
		i++;
	}

	if (!unlocked) {
		if (quiet < 2)
			fprintf(stderr, "Unlocking %s ...\n", device);
		mtd_unlock(device);
	}

	switch (cmd) {
		case CMD_UNLOCK:
			break;
		case CMD_ERASE:
			if (unlocked) {
				fprintf(stderr, "Already erased: %s\n", device);
				break;
			}
			if (quiet < 2)
				fprintf(stderr, "Erasing %s ...\n", device);
			mtd_erase(device);
			break;
		case CMD_WRITE:
			if (quiet < 2)
				fprintf(stderr, "Writing from %s to %s ... ", imagefile, device);
			mtd_write(imagefd, device, quiet, (unlocked == 0));
			if (quiet < 2)
				fprintf(stderr, "\n");
			break;
	}
	
	sync();
	if (boot) {
		fprintf(stderr, "\nRebooting ... ");
		fflush(stdout);
		fflush(stderr);
		syscall(SYS_reboot,LINUX_REBOOT_MAGIC1,LINUX_REBOOT_MAGIC2,LINUX_REBOOT_CMD_RESTART,NULL);
	}	
	return 0;
}
