/*
 * U-Boot utility program for Linux
 *
 * Copyright (C) 2010 by Multi-Tech Systems
 *
 * Author: James Maki <jmaki@multitech.com>
 *
 * 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
 *
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <zlib.h>

#include "u_boot.h"

static int tokcmp(const char *cmd, const char *pattern) {
	int len = strlen(cmd);
	if (len > strlen(pattern)) {
		return -1;
	}

	return memcmp(pattern, cmd, len);
}

#define ENV_HEADER_SIZE		(sizeof(uint32_t) + sizeof(uint8_t))
#define ENV_DATA_SIZE		(MTD_SIZE - ENV_HEADER_SIZE)

struct environment {
	uint32_t crc;
	uint8_t flags;
	char data[ENV_DATA_SIZE];
};

static int write_uboot_env(const char *device, struct environment *env)
{
	int err;
	int fd;

	err = mtd_erase_all(device, 0);
	if (!err) {
		error("mtd_erase_all %s failed", device);
		return -1;
	}

	fd = open(device, O_WRONLY);
	if (fd < 0) {
		error("open %s failed: %d", device, errno);
		return -1;
	}

	err = write(fd, env, sizeof(*env));
	if (err != sizeof(*env)) {
		error("write to %s failed: %d", device, errno);
		close(fd);
		return -1;
	}

	close(fd);

	return err;
}

static int read_uboot_env(const char *device, struct environment *env)
{
	int fd;
	int err;

	memset(env, 0, sizeof(*env));

	fd = open(device, O_RDONLY);
	if (fd < 0) {
		error("open %s failed: %d", device, errno);
		return -1;
	}

	err = read(fd, env, sizeof(*env));
	if (err != sizeof(*env)) {
		error("read from %s failed: %d", device, errno);
		close(fd);
		return -1;
	}

	close(fd);

	return err;
}

static char *next_var(const char *var)
{
	return (char *) (var + strlen(var) + 1);
}

static int cmd_printenv(struct environment *env, int argc, char **argv)
{
	char *var;
	char *name = NULL;
	size_t name_len = 0;

	if (argc) {
		name = *argv;
		name_len = strlen(name);
	}

	var = env->data;
	while (*var) {
		if (!name) {
			printf("%s\n", var);
		} else if (!strncmp(var, name, name_len) && var[name_len] == '=') {
			printf("%s\n", var);
			return true;
		}

		var = next_var(var);
	}

	if (name) {
		fprintf(stderr, "environment variable not found\n");
		return false;
	}

	return true;
}

static int cmd_setenv(struct environment *env, int argc, char **argv)
{
	int tmp;
	char *var;
	char *cp;
	char *end = env->data + sizeof(env->data);
	char *name;
	size_t name_len;
	size_t value_len;

	if (!argc) {
		fprintf(stderr, "name expected\n");
		return false;
	}
	name = *argv;
	argc--; argv++;

	name_len = strlen(name);

	var = env->data;
	while (*var) {
		if (!strncmp(var, name, name_len) && var[name_len] == '=') {
			dbg("found variable (%s) at %lld", var, (long long int) var);

			cp = next_var(var);
			while (*cp) {
				while (*cp) {
					*var++ = *cp++;
				}
				*var++ = *cp++;
			}

			break;
		}

		var = next_var(var);
	}

	value_len = 0;
	for (tmp = 0; tmp < argc; tmp++) {
		value_len += strlen(argv[tmp]);
		if (tmp + 1 < argc) {
			value_len += 1;
		}
	}

	if (value_len) {
		if (var + strlen(name) + strlen("=") + value_len + 1 >= end) {
			error("end of environment reached");
			return false;
		}
		*var = 0;
		strcat(var, name);
		strcat(var, "=");
		for (tmp = 0; tmp < argc; tmp++) {
			strcat(var, argv[tmp]);
			if (tmp + 1 < argc) {
				strcat(var, " ");
			}
		}
		var += strlen(var) + 1;
	}

	*var = 0;
	if (var == env->data) {
		*(var + 1) = 0;
	}

	env->crc = crc32(0, (uint8_t *) env->data, sizeof(env->data));
	dbg("crc: 0x%08X", env->crc);
	env->flags = 0;

	tmp = write_uboot_env(MTD_ENV1, env);
	if (tmp < 0) {
		dbg("write_uboot_env %s failed with %d", MTD_ENV1, tmp);
	}
	tmp = write_uboot_env(MTD_ENV2, env);
	if (tmp < 0) {
		dbg("write_uboot_env %s failed with %d", MTD_ENV1, tmp);
	}

	return true;
}

static void print_version(const char *name) {
	printf("%s (" PACKAGE ") " VERSION " (" __DATE__ " " __TIME__ ")\n", name);
	printf("Copyright (C) 2010 by Multi-Tech Systems\n");
	printf(
"This program is free software; you may redistribute it under the terms of\n"
"the GNU General Public License version 2 or (at your option) any later version.\n"
"This program has absolutely no warranty.\n");
}

static void usage(FILE *out) {
	fprintf(out, "Usage: u-boot { printenv [ name ] | setenv name [ value ] }\n");
	fprintf(out, "\n");
}

int main(int argc, char *argv[]) {
	int err;
	char *cmd;
	char *option;
	struct environment *env = NULL;

	struct environment *env1;
	struct environment *env2;
	uint32_t crc1_ok;
	uint32_t crc2_ok;

	if (argc <= 1) {
		usage(stderr);
		exit(1);
	}
	argc--; argv++;

	while (argc) {
		option = *argv;
		if (*option != '-') {
			break;
		} else if (!strcmp(option, "--")) {
			break;
		} else if (!strcmp(option, "--version")) {
			print_version("u-boot");
			exit(0);
		} else if (!strcmp(option, "--help")) {
			usage(stdout);
			exit(0);
		} else {
			usage(stderr);
			exit(1);
		}

		argc--; argv++;
	}

	if (!argc) {
		usage(stderr);
		exit(1);
	}

	env1 = malloc(sizeof(struct environment));
	if (!env1) {
		error("out of memory");
		return 1;
	}

	env2 = malloc(sizeof(struct environment));
	if (!env2) {
		error("out of memory");
		return 1;
	}

	err = read_uboot_env(MTD_ENV1, env1);
	if (err < 0) {
		error("read_uboot_env failed");
		return 1;
	}
	dbg("env1 crc: 0x%08X", env1->crc);
	dbg("env1 flags: %d", env1->flags);
	if (crc32(0, (uint8_t *) env1->data, sizeof(env1->data)) == env1->crc) {
		crc1_ok = 1;
	} else {
		error("crc does not match on primary env");
		crc1_ok = 0;
	}

	err = read_uboot_env(MTD_ENV2, env2);
	if (err < 0) {
		error("read_uboot_env failed");
		return 1;
	}
	dbg("env2 crc: 0x%08X", env2->crc);
	dbg("env2 flags: %d", env2->flags);
	if (crc32(0, (uint8_t *) env2->data, sizeof(env2->data)) == env2->crc) {
		crc2_ok = 1;
	} else {
		error("crc does not match on redundant env");
		crc2_ok = 0;
	}

	if (!crc1_ok && !crc2_ok) {
		error("both environments are bad: loading DEFAULT_ENV");
		env = env1;
		env->flags = 0;
		memcpy(env->data, DEFAULT_ENV, sizeof(DEFAULT_ENV));
	} else if (crc1_ok && !crc2_ok) {
		env = env1;
	} else if (!crc1_ok && crc2_ok) {
		env = env2;
	} else {
		if (env1->flags == 255 && env2->flags == 0) {
			env = env2;
		} else if (env2->flags == 255 && env1->flags == 0) {
			env = env1;
		} else if (env1->flags > env2->flags) {
			env = env1;
		} else if (env2->flags > env1->flags) {
			env = env2;
		} else {
			env = env1;
		}
	}

	cmd = *argv;
	argc--; argv++;
	if (!tokcmp(cmd, "printenv")) {
		err = cmd_printenv(env, argc, argv);
	} else if (!tokcmp(cmd, "setenv")) {
		err = cmd_setenv(env, argc, argv);
	} else {
		usage(stderr);
		exit(1);
	}

	return !err;
}