// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2000-2010
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * (C) Copyright 2008
 * Guennadi Liakhovetski, DENX Software Engineering, lg@denx.de.
 */

#define _GNU_SOURCE

#include <errno.h>
#include <env_flags.h>
#include <fcntl.h>
#include <libgen.h>
#include <linux/fs.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>

#include "fw_env_private.h"
#include "fw_env.h"

#define min(x, y) ({				\
	typeof(x) _min1 = (x);			\
	typeof(y) _min2 = (y);			\
	(void) (&_min1 == &_min2);		\
	_min1 < _min2 ? _min1 : _min2; })

#define ENV_SIZE     (ENV_SIZE_BYTE - sizeof(uint32_t)) 

struct env_image_single {
	uint32_t crc;		/* CRC32 over data bytes    */
	char data[];
};

enum flag_scheme {
	FLAG_NONE,
	FLAG_BOOLEAN,
	FLAG_INCREMENTAL,
};

struct environment {
	void *image;
	uint32_t *crc;
	unsigned char *flags;
	char *data;
	enum flag_scheme flag_scheme;
};

static struct environment environment = {
	.flag_scheme = FLAG_NONE,
};

#include <env_default.h>

static int flash_io(int mode);
static char *skip_chars(char *s)
{
	for (; *s != '\0'; s++) {
		if (isblank(*s) || *s == '=')
			return s;
	}
	return NULL;
}

static char *skip_blanks(char *s)
{
	for (; *s != '\0'; s++) {
		if (!isblank(*s))
			return s;
	}
	return NULL;
}

/*
 * s1 is either a simple 'name', or a 'name=value' pair.
 * s2 is a 'name=value' pair.
 * If the names match, return the value of s2, else NULL.
 */
static char *envmatch(char *s1, char *s2)
{
	if (s1 == NULL || s2 == NULL)
		return NULL;

	while (*s1 == *s2++)
		if (*s1++ == '=')
			return s2;
	if (*s1 == '\0' && *(s2 - 1) == '=')
		return s2;
	return NULL;
}

/**
 * Search the environment for a variable.
 * Return the value, if found, or NULL, if not found.
 */
char *fw_getenv(char *name)
{
	char *env, *nxt;

	for (env = environment.data; *env; env = nxt + 1) {
		char *val;

		for (nxt = env; *nxt; ++nxt) {
			if (nxt >= &environment.data[ENV_SIZE]) {
				fprintf(stderr, "## Error: "
					"environment not terminated\n");
				return NULL;
			}
		}
		val = envmatch(name, env);
		if (!val)
			continue;
		return val;
	}
	return NULL;
}

/*
 * Search the default environment for a variable.
 * Return the value, if found, or NULL, if not found.
 */
char *fw_getdefenv(char *name)
{
	char *env, *nxt;

	for (env = default_environment; *env; env = nxt + 1) {
		char *val;

		for (nxt = env; *nxt; ++nxt) {
			if (nxt >= &default_environment[ENV_SIZE]) {
				fprintf(stderr, "## Error: "
					"default environment not terminated\n");
				return NULL;
			}
		}
		val = envmatch(name, env);
		if (!val)
			continue;
		return val;
	}
	return NULL;
}

/*
 * Print the current definition of one, or more, or all
 * environment variables
 */
int fw_printenv(int argc, char *argv[], int value_only)
{
	int i, rc = 0;

	if (value_only && argc != 1) {
		fprintf(stderr,
			"## Error: `-n'/`--noheader' option requires exactly one argument\n");
		return -1;
	}

	if (fw_env_init())
		return -1;

	if(flash_io(O_RDONLY) != 0){
		perror("fw_printenv flash_io error\n");
		return -1;
	}

	if (argc == 0) {	/* Print all env variables  */
		char *env, *nxt;
		for (env = environment.data; *env; env = nxt + 1) {
			for (nxt = env; *nxt; ++nxt) {
				if (nxt >= &environment.data[ENV_SIZE]) {
					fprintf(stderr, "## Error: "
						"environment not terminated\n");
					return -1;
				}
			}

			printf("%s\n", env);
		}
		fw_env_close();
		return 0;
	}

	for (i = 0; i < argc; ++i) {	/* print a subset of env variables */
		char *name = argv[i];
		char *val = NULL;

		val = fw_getenv(name);
		if (!val) {
			fprintf(stderr, "## Error: \"%s\" not defined\n", name);
			rc = -1;
			continue;
		}

		if (value_only) {
			puts(val);
			break;
		}

		printf("%s=%s\n", name, val);
	}

	fw_env_close();

	return rc;
}

int fw_env_flush(void)
{
	/*
	 * Update CRC
	 */
	*environment.crc = crc32(0, (uint8_t *) environment.data, ENV_SIZE);

	/* write environment back to flash */
	if (flash_io(O_RDWR)) {
		fprintf(stderr, "Error: can't write fw_env to binary file\n");
		return -1;
	}

	return 0;
}

/*
 * Set/Clear a single variable in the environment.
 * This is called in sequence to update the environment
 * in RAM without updating the copy in flash after each set
 */
int fw_env_write(char *name, char *value)
{
	int len;
	char *env, *nxt;
	char *oldval = NULL;
	int deleting, creating, overwriting;

	/*
	 * search if variable with this name already exists
	 */
	for (nxt = env = environment.data; *env; env = nxt + 1) {
		for (nxt = env; *nxt; ++nxt) {
			if (nxt >= &environment.data[ENV_SIZE]) {
				fprintf(stderr, "## Error: "
					"environment not terminated\n");
				errno = EINVAL;
				return -1;
			}
		}
		oldval = envmatch(name, env);
		if (oldval)
			break;
	}

	deleting = (oldval && !(value && strlen(value)));
	creating = (!oldval && (value && strlen(value)));
	overwriting = (oldval && (value && strlen(value)));

	/* check for permission */
	if (deleting) {
		if (env_flags_validate_varaccess(name,
		    ENV_FLAGS_VARACCESS_PREVENT_DELETE)) {
			printf("Can't delete \"%s\"\n", name);
			errno = EROFS;
			return -1;
		}
	} else if (overwriting) {
		if (env_flags_validate_varaccess(name,
		    ENV_FLAGS_VARACCESS_PREVENT_OVERWR)) {
			printf("Can't overwrite \"%s\"\n", name);
			errno = EROFS;
			return -1;
		} else if (env_flags_validate_varaccess(name,
			   ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR)) {
			const char *defval = fw_getdefenv(name);

			if (defval == NULL)
				defval = "";
			if (strcmp(oldval, defval)
			    != 0) {
				printf("Can't overwrite \"%s\"\n", name);
				errno = EROFS;
				return -1;
			}
		}
	} else if (creating) {
		if (env_flags_validate_varaccess(name,
		    ENV_FLAGS_VARACCESS_PREVENT_CREATE)) {
			printf("Can't create \"%s\"\n", name);
			errno = EROFS;
			return -1;
		}
	} else
		/* Nothing to do */
		return 0;

	if (deleting || overwriting) {
		if (*++nxt == '\0') {
			*env = '\0';
		} else {
			for (;;) {
				*env = *nxt++;
				if ((*env == '\0') && (*nxt == '\0'))
					break;
				++env;
			}
		}
		*++env = '\0';
	}

	/* Delete only ? */
	if (!value || !strlen(value))
		return 0;

	/*
	 * Append new definition at the end
	 */
	for (env = environment.data; *env || *(env + 1); ++env)
		;
	if (env > environment.data)
		++env;
	/*
	 * Overflow when:
	 * "name" + "=" + "val" +"\0\0"  > CUR_ENVSIZE - (env-environment)
	 */
	len = strlen(name) + 2;
	/* add '=' for first arg, ' ' for all others */
	len += strlen(value) + 1;

	if (len > (&environment.data[ENV_SIZE] - env)) {
		fprintf(stderr,
			"Error: environment overflow, \"%s\" deleted\n", name);
		return -1;
	}

	while ((*env = *name++) != '\0')
		env++;
	*env = '=';
	while ((*++env = *value++) != '\0')
		;

	/* end is marked with double '\0' */
	*++env = '\0';

	return 0;
}

/*
 * Deletes or sets environment variables. Returns -1 and sets errno error codes:
 * 0	  - OK
 * EINVAL - need at least 1 argument
 * EROFS  - certain variables ("ethaddr", "serial#") cannot be
 *	    modified or deleted
 *
 */
int fw_env_set(int argc, char *argv[])
{
	int i;
	size_t len;
	char *name, **valv;
	char *oldval;
	char *value = NULL;
	int valc;
	int ret;

	if (argc < 1) {
		fprintf(stderr, "## Error: variable name missing\n");
		errno = EINVAL;
		return -1;
	}

	if (fw_env_init()) {
		fprintf(stderr, "Error: environment not initialized\n");
		return -1;
	}
	
	if(flash_io(O_RDONLY) != 0){
		perror("fw_env_set flash_io error\n");
		return -1;
	}

	name = argv[0];
	valv = argv + 1;
	valc = argc - 1;

	if (env_flags_validate_env_set_params(name, valv, valc) < 0) {
		fw_env_close();
		return -1;
	}

	len = 0;
	for (i = 0; i < valc; ++i) {
		char *val = valv[i];
		size_t val_len = strlen(val);

		if (value)
			value[len - 1] = ' ';
		oldval = value;
		value = realloc(value, len + val_len + 1);
		if (!value) {
			fprintf(stderr,
				"Cannot malloc %zu bytes: %s\n",
				len, strerror(errno));
			free(oldval);
			return -1;
		}

		memcpy(value + len, val, val_len);
		len += val_len;
		value[len++] = '\0';
	}

	fw_env_write(name, value);

	free(value);

	ret = fw_env_flush();
	fw_env_close();

	return ret;
}

/*
 * Parse  a file  and configure the u-boot variables.
 * The script file has a very simple format, as follows:
 *
 * Each line has a couple with name, value:
 * <white spaces>variable_name<white spaces>variable_value
 *
 * Both variable_name and variable_value are interpreted as strings.
 * Any character after <white spaces> and before ending \r\n is interpreted
 * as variable's value (no comment allowed on these lines !)
 *
 * Comments are allowed if the first character in the line is #
 *
 * Returns -1 and sets errno error codes:
 * 0	  - OK
 * -1     - Error
 */
int fw_parse_script(char *fname)
{
	FILE *fp;
	char *line = NULL;
	size_t linesize = 0;
	char *name;
	char *val;
	int lineno = 0;
	int len;
	int ret = 0;

	if (fw_env_init()) {
		fprintf(stderr, "Error: environment not initialized\n");
		return -1;
	}

	if (strcmp(fname, "-") == 0)
		fp = stdin;
	else {
		fp = fopen(fname, "r");
		if (fp == NULL) {
			fprintf(stderr, "I cannot open %s for reading\n",
				fname);
			return -1;
		}
	}

	while ((len = getline(&line, &linesize, fp)) != -1) {
		lineno++;

		/*
		 * Read a whole line from the file. If the line is not
		 * terminated, reports an error and exit.
		 */
		if (line[len - 1] != '\n') {
			fprintf(stderr,
				"Line %d not correctly terminated\n",
				lineno);
			ret = -1;
			break;
		}

		/* Drop ending line feed / carriage return */
		line[--len] = '\0';
		if (len && line[len - 1] == '\r')
			line[--len] = '\0';

		/* Skip comment or empty lines */
		if (len == 0 || line[0] == '#')
			continue;

		/*
		 * Search for variable's name remove leading whitespaces
		 */
		name = skip_blanks(line);
		if (!name)
			continue;

		/* The first white space is the end of variable name */
		val = skip_chars(name);
		len = strlen(name);
		if (val) {
			*val++ = '\0';
			if ((val - name) < len)
				val = skip_blanks(val);
			else
				val = NULL;
		}
#ifdef DEBUG
		fprintf(stderr, "Setting %s : %s\n",
			name, val ? val : " removed");
#endif

		if (env_flags_validate_type(name, val) < 0) {
			ret = -1;
			break;
		}

		/*
		 * If there is an error setting a variable,
		 * try to save the environment and returns an error
		 */
		if (fw_env_write(name, val)) {
			fprintf(stderr,
				"fw_env_write returns with error : %s\n",
				strerror(errno));
			ret = -1;
			break;
		}

	}
	free(line);

	/* Close file if not stdin */
	if (strcmp(fname, "-") != 0)
		fclose(fp);

	ret |= fw_env_flush();

	fw_env_close();

	return ret;
}

static int flash_io_read(int fd_current)
{
	void *data = environment.image;
	struct stat sb;
	off_t rsectlen = 0;
	
	if(fstat(fd_current, &sb) != 0){
		fprintf(stderr, "fstat file %s failed: %s\n", ENV_IMG_FILE_NAME, strerror(errno));
		return -1;
	}
	
	for(rsectlen = 0; rsectlen < sb.st_size; data += 4096){
		if (sb.st_size - rsectlen >= 4096){
			if(read(fd_current, data, 4096) != 4096){
				fprintf(stderr, "Write error on %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));	
				return -1;	
			}
			rsectlen += 4096;
		} else{
			if(read(fd_current, data, sb.st_size - rsectlen) != sb.st_size - rsectlen){
				fprintf(stderr, "Write error on %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));
				return -1;
			}
			rsectlen = sb.st_size;
		}
	}

	return 0;
}

static int flash_io_write(int fd_current)
{
	void *data = environment.image;

	for(int wsectlen = 0; wsectlen < ENV_SIZE_BYTE; data += 4096){
		if (ENV_SIZE_BYTE - wsectlen >= 4096){
			if(write(fd_current, data, 4096) != 4096){
				fprintf(stderr, "Write error on %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));	
				return -1;	
			}
			wsectlen += 4096;
		} else{
			if(write(fd_current, data, ENV_SIZE_BYTE - wsectlen) != ENV_SIZE_BYTE - wsectlen){
				fprintf(stderr, "Write error on %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));
				return -1;
			}
			wsectlen = ENV_SIZE_BYTE;
		}
	}

	return 0;
}

static int flash_io(int mode)
{
	int fd_current, rc;

	if(mode == O_RDONLY){		// fw_printenv
		if(access(ENV_IMG_FILE_NAME, F_OK | R_OK) == 0){		// if ENV_IMG_FILE_NAME exist, we parse it!
			fd_current = open(ENV_IMG_FILE_NAME, mode);
			if (fd_current < 0) {
				fprintf(stderr, "Can't open %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));
				return -1;
			}
			rc = flash_io_read(fd_current);
		}else{													// else we use default environment, and write it to %ENV_IMG_FILE_NAME
			fprintf(stdout, "%s isn't exist or cannot be read, use default environment", ENV_IMG_FILE_NAME);
			memcpy(environment.data, default_environment, sizeof(default_environment));
			fw_env_flush();
			return 0;
		}
	}else{			// fw_setenv or fw_printenv write to %ENV_IMG_FILE_NAME
		fd_current = open(ENV_IMG_FILE_NAME, mode | O_CREAT | O_TRUNC, 0666);
		if (fd_current < 0) {
			fprintf(stderr, "Can't open %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));
			return -1;
		}
		rc = flash_io_write(fd_current);
	}

	if (close(fd_current)) {
		fprintf(stderr, "I/O error on %s: %s\n", ENV_IMG_FILE_NAME, strerror(errno));
		return -1;
	}

	return rc;
}

/*
 * Prevent confusion if running from erased flash memory
 */
int fw_env_init(void)
{
	void *addr0 = NULL;
	struct env_image_single *single;
	int ret;

	addr0 = calloc(1, ENV_SIZE_BYTE);
	if (addr0 == NULL) {
		fprintf(stderr, "Not enough memory for environment (%ld bytes)\n", (long)ENV_SIZE_BYTE);
		ret = -ENOMEM;
		goto open_cleanup;
	}

	environment.image = addr0;
	single = addr0;
	environment.crc = &single->crc;
	environment.flags = NULL;
	environment.data = single->data;
	
	// don't use default environment defaultly
//	memcpy(environment.data, default_environment, sizeof(default_environment));

	return 0;

open_cleanup:
	if (addr0)
		free(addr0);

	return ret;
}

/*
 * Simply free allocated buffer with environment
 */
int fw_env_close(void)
{
	if (environment.image)
		free(environment.image);

	environment.image = NULL;

	return 0;
}