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  •  * (C) Copyright 2000-2008
    
     * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
     *
    
     * (C) Copyright 2008
     * Guennadi Liakhovetski, DENX Software Engineering, lg@denx.de.
     *
    
     * See file CREDITS for list of people who contributed to this
     * project.
     *
     * 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 <errno.h>
    #include <fcntl.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 <stdint.h>
    
    # include <linux/mtd/mtd.h>
    #else
    
    # define  __user	/* nothing */
    
    # include <mtd/mtd-user.h>
    #endif
    
    #include "fw_env.h"
    
    
    #define	CMD_GETENV	"fw_printenv"
    #define	CMD_SETENV	"fw_setenv"
    
    
    #define min(x, y) ({				\
    	typeof(x) _min1 = (x);			\
    	typeof(y) _min2 = (y);			\
    	(void) (&_min1 == &_min2);		\
    	_min1 < _min2 ? _min1 : _min2; })
    
    struct envdev_s {
    
    	char devname[16];		/* Device name */
    
    	ulong devoff;			/* Device offset */
    	ulong env_size;			/* environment size */
    	ulong erase_size;		/* device erase size */
    
    	ulong env_sectors;		/* number of environment sectors */
    	uint8_t mtd_type;		/* type of the MTD device */
    };
    
    static struct envdev_s envdevices[2] =
    {
    	{
    		.mtd_type = MTD_ABSENT,
    	}, {
    		.mtd_type = MTD_ABSENT,
    	},
    };
    static int dev_current;
    
    
    #define DEVNAME(i)    envdevices[(i)].devname
    
    #define DEVOFFSET(i)  envdevices[(i)].devoff
    
    #define ENVSIZE(i)    envdevices[(i)].env_size
    #define DEVESIZE(i)   envdevices[(i)].erase_size
    
    #define ENVSECTORS(i) envdevices[(i)].env_sectors
    #define DEVTYPE(i)    envdevices[(i)].mtd_type
    
    #define CFG_ENV_SIZE ENVSIZE(dev_current)
    
    #define ENV_SIZE      getenvsize()
    
    struct env_image_single {
    	uint32_t	crc;	/* CRC32 over data bytes    */
    	char		data[];
    };
    
    struct env_image_redundant {
    	uint32_t	crc;	/* CRC32 over data bytes    */
    	unsigned char	flags;	/* active or obsolete */
    	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,
    };
    
    static int HaveRedundEnv = 0;
    
    
    static unsigned char active_flag = 1;
    
    /* obsolete_flag must be 0 to efficiently set it on NOR flash without erasing */
    
    static unsigned char obsolete_flag = 0;
    
    
    #define XMK_STR(x)	#x
    #define MK_STR(x)	XMK_STR(x)
    
    
    static char default_environment[] = {
    
    #if defined(CONFIG_BOOTARGS)
    
    	"bootargs=" CONFIG_BOOTARGS "\0"
    
    #if defined(CONFIG_BOOTCOMMAND)
    
    	"bootcmd=" CONFIG_BOOTCOMMAND "\0"
    
    #if defined(CONFIG_RAMBOOTCOMMAND)
    
    	"ramboot=" CONFIG_RAMBOOTCOMMAND "\0"
    
    #endif
    #if defined(CONFIG_NFSBOOTCOMMAND)
    
    	"nfsboot=" CONFIG_NFSBOOTCOMMAND "\0"
    
    #endif
    #if defined(CONFIG_BOOTDELAY) && (CONFIG_BOOTDELAY >= 0)
    
    	"bootdelay=" MK_STR (CONFIG_BOOTDELAY) "\0"
    
    #if defined(CONFIG_BAUDRATE) && (CONFIG_BAUDRATE >= 0)
    
    	"baudrate=" MK_STR (CONFIG_BAUDRATE) "\0"
    
    #ifdef	CONFIG_LOADS_ECHO
    
    	"loads_echo=" MK_STR (CONFIG_LOADS_ECHO) "\0"
    
    	"ethaddr=" MK_STR (CONFIG_ETHADDR) "\0"
    
    	"eth1addr=" MK_STR (CONFIG_ETH1ADDR) "\0"
    
    #endif
    #ifdef	CONFIG_ETH2ADDR
    
    	"eth2addr=" MK_STR (CONFIG_ETH2ADDR) "\0"
    
    #ifdef	CONFIG_ETH3ADDR
    	"eth3addr=" MK_STR (CONFIG_ETH3ADDR) "\0"
    #endif
    
    	"ethprime=" CONFIG_ETHPRIME "\0"
    
    	"ipaddr=" MK_STR (CONFIG_IPADDR) "\0"
    
    #endif
    #ifdef	CONFIG_SERVERIP
    
    	"serverip=" MK_STR (CONFIG_SERVERIP) "\0"
    
    	"autoload=" CFG_AUTOLOAD "\0"
    
    #endif
    #ifdef	CONFIG_ROOTPATH
    
    	"rootpath=" MK_STR (CONFIG_ROOTPATH) "\0"
    
    #endif
    #ifdef	CONFIG_GATEWAYIP
    
    	"gatewayip=" MK_STR (CONFIG_GATEWAYIP) "\0"
    
    #endif
    #ifdef	CONFIG_NETMASK
    
    	"netmask=" MK_STR (CONFIG_NETMASK) "\0"
    
    #endif
    #ifdef	CONFIG_HOSTNAME
    
    	"hostname=" MK_STR (CONFIG_HOSTNAME) "\0"
    
    #endif
    #ifdef	CONFIG_BOOTFILE
    
    	"bootfile=" MK_STR (CONFIG_BOOTFILE) "\0"
    
    #endif
    #ifdef	CONFIG_LOADADDR
    
    	"loadaddr=" MK_STR (CONFIG_LOADADDR) "\0"
    
    #endif
    #ifdef	CONFIG_PREBOOT
    
    	"preboot=" CONFIG_PREBOOT "\0"
    
    #endif
    #ifdef	CONFIG_CLOCKS_IN_MHZ
    
    	"clocks_in_mhz=" "1" "\0"
    
    #if defined(CONFIG_PCI_BOOTDELAY) && (CONFIG_PCI_BOOTDELAY > 0)
    
    	"pcidelay=" MK_STR (CONFIG_PCI_BOOTDELAY) "\0"
    
    #ifdef  CONFIG_EXTRA_ENV_SETTINGS
    	CONFIG_EXTRA_ENV_SETTINGS
    #endif
    
    	"\0"		/* Termimate struct environment data with 2 NULs */
    
    static int flash_io (int mode);
    
    static char *envmatch (char * s1, char * s2);
    
    static int env_init (void);
    static int parse_config (void);
    
    
    #if defined(CONFIG_FILE)
    
    static int get_config (char *);
    
    static inline ulong getenvsize (void)
    
    	ulong rc = CFG_ENV_SIZE - sizeof (long);
    
    
    		rc -= sizeof (char);
    
    
    /*
     * Search the environment for a variable.
     * Return the value, if found, or NULL, if not found.
     */
    
    char *fw_getenv (char *name)
    
    	if (env_init ())
    
    		return NULL;
    
    	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 NULL;
    
    		val = envmatch (name, env);
    
    		return val;
    
    	return NULL;
    
    }
    
    /*
     * Print the current definition of one, or more, or all
     * environment variables
     */
    
    int fw_printenv (int argc, char *argv[])
    
    	if (env_init ())
    
    		return -1;
    
    	if (argc == 1) {		/* Print all env variables  */
    		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);
    
    		return 0;
    
    	if (strcmp (argv[1], "-n") == 0) {
    
    		n_flag = 1;
    		++argv;
    		--argc;
    		if (argc != 2) {
    			fprintf (stderr, "## Error: "
    				"`-n' option requires exactly one argument\n");
    
    			return -1;
    
    	for (i = 1; i < argc; ++i) {	/* print single env variables   */
    
    		char *name = argv[i];
    		char *val = NULL;
    
    		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;
    
    			val = envmatch (name, env);
    
    			if (val) {
    				if (!n_flag) {
    					fputs (name, stdout);
    
    					putc ('=', stdout);
    
    				puts (val);
    
    			fprintf (stderr, "## Error: \"%s\" not defined\n", name);
    
    	return rc;
    
     * 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_setenv (int argc, char *argv[])
    {
    
    	int i, len;
    
    	char *env, *nxt;
    	char *oldval = NULL;
    	char *name;
    
    		errno = EINVAL;
    		return -1;
    
    	if (env_init ())
    
    		return -1;
    
    
    	name = argv[1];
    
    	/*
    	 * 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;
    
    		if ((oldval = envmatch (name, env)) != NULL)
    
    			break;
    	}
    
    	/*
    	 * Delete any existing definition
    	 */
    	if (oldval) {
    		/*
    		 * Ethernet Address and serial# can be set only once
    		 */
    		if ((strcmp (name, "ethaddr") == 0) ||
    
    			(strcmp (name, "serial#") == 0)) {
    
    			fprintf (stderr, "Can't overwrite \"%s\"\n", name);
    
    			errno = EROFS;
    			return -1;
    
    		}
    
    		if (*++nxt == '\0') {
    			*env = '\0';
    		} else {
    			for (;;) {
    				*env = *nxt++;
    				if ((*env == '\0') && (*nxt == '\0'))
    					break;
    				++env;
    			}
    		}
    		*++env = '\0';
    	}
    
    	/* Delete only ? */
    	if (argc < 3)
    		goto WRITE_FLASH;
    
    	/*
    	 * 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"  > CFG_ENV_SIZE - (env-environment)
    	 */
    
    	len = strlen (name) + 2;
    
    	/* add '=' for first arg, ' ' for all others */
    
    	for (i = 2; i < argc; ++i) {
    		len += strlen (argv[i]) + 1;
    
    	if (len > (&environment.data[ENV_SIZE] - env)) {
    
    		fprintf (stderr,
    			"Error: environment overflow, \"%s\" deleted\n",
    			name);
    
    		return -1;
    
    	}
    	while ((*env = *name++) != '\0')
    		env++;
    
    	for (i = 2; i < argc; ++i) {
    
    		char *val = argv[i];
    
    		*env = (i == 2) ? '=' : ' ';
    		while ((*++env = *val++) != '\0');
    
    	}
    
    	/* end is marked with double '\0' */
    	*++env = '\0';
    
    
      WRITE_FLASH:
    
    	/*
    	 * 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 flash\n");
    
    		return -1;
    
    	return 0;
    
    /*
     * Test for bad block on NAND, just returns 0 on NOR, on NAND:
     * 0	- block is good
     * > 0	- block is bad
     * < 0	- failed to test
     */
    static int flash_bad_block (int fd, uint8_t mtd_type, loff_t *blockstart)
    
    	if (mtd_type == MTD_NANDFLASH) {
    		int badblock = ioctl (fd, MEMGETBADBLOCK, blockstart);
    
    		if (badblock < 0) {
    			perror ("Cannot read bad block mark");
    			return badblock;
    		}
    
    		if (badblock) {
    #ifdef DEBUG
    			fprintf (stderr, "Bad block at 0x%llx, "
    				 "skipping\n", *blockstart);
    #endif
    			return badblock;
    		}
    
    	return 0;
    }
    
    /*
     * Read data from flash at an offset into a provided buffer. On NAND it skips
     * bad blocks but makes sure it stays within ENVSECTORS (dev) starting from
     * the DEVOFFSET (dev) block. On NOR the loop is only run once.
     */
    static int flash_read_buf (int dev, int fd, void *buf, size_t count,
    			   off_t offset, uint8_t mtd_type)
    {
    	size_t blocklen;	/* erase / write length - one block on NAND,
    				   0 on NOR */
    	size_t processed = 0;	/* progress counter */
    	size_t readlen = count;	/* current read length */
    	off_t top_of_range;	/* end of the last block we may use */
    	off_t block_seek;	/* offset inside the current block to the start
    				   of the data */
    	loff_t blockstart;	/* running start of the current block -
    				   MEMGETBADBLOCK needs 64 bits */
    	int rc;
    
    	/*
    	 * Start of the first block to be read, relies on the fact, that
    	 * erase sector size is always a power of 2
    	 */
    	blockstart = offset & ~(DEVESIZE (dev) - 1);
    
    	/* Offset inside a block */
    	block_seek = offset - blockstart;
    
    	if (mtd_type == MTD_NANDFLASH) {
    		/*
    		 * NAND: calculate which blocks we are reading. We have
    		 * to read one block at a time to skip bad blocks.
    		 */
    		blocklen = DEVESIZE (dev);
    
    		/*
    		 * To calculate the top of the range, we have to use the
    		 * global DEVOFFSET (dev), which can be different from offset
    		 */
    		top_of_range = (DEVOFFSET (dev) & ~(blocklen - 1)) +
    			ENVSECTORS (dev) * blocklen;
    
    		/* Limit to one block for the first read */
    		if (readlen > blocklen - block_seek)
    			readlen = blocklen - block_seek;
    	} else {
    		blocklen = 0;
    		top_of_range = offset + count;
    
    	/* This only runs once on NOR flash */
    	while (processed < count) {
    		rc = flash_bad_block (fd, mtd_type, &blockstart);
    		if (rc < 0)		/* block test failed */
    			return -1;
    
    		if (blockstart + block_seek + readlen > top_of_range) {
    			/* End of range is reached */
    			fprintf (stderr,
    				 "Too few good blocks within range\n");
    			return -1;
    
    		if (rc) {		/* block is bad */
    			blockstart += blocklen;
    			continue;
    
    		/*
    		 * If a block is bad, we retry in the next block at the same
    		 * offset - see common/env_nand.c::writeenv()
    		 */
    		lseek (fd, blockstart + block_seek, SEEK_SET);
    
    		rc = read (fd, buf + processed, readlen);
    		if (rc != readlen) {
    			fprintf (stderr, "Read error on %s: %s\n",
    				 DEVNAME (dev), strerror (errno));
    			return -1;
    
    #ifdef DEBUG
    		fprintf (stderr, "Read 0x%x bytes at 0x%llx\n",
    			 rc, blockstart + block_seek);
    #endif
    		processed += readlen;
    		readlen = min (blocklen, count - processed);
    		block_seek = 0;
    		blockstart += blocklen;
    	}
    
    	return processed;
    }
    
    /*
     * Write count bytes at offset, but stay within ENVSETCORS (dev) sectors of
     * DEVOFFSET (dev). Similar to the read case above, on NOR we erase and write
     * the whole data at once.
     */
    static int flash_write_buf (int dev, int fd, void *buf, size_t count,
    			    off_t offset, uint8_t mtd_type)
    {
    	void *data;
    	struct erase_info_user erase;
    	size_t blocklen;	/* length of NAND block / NOR erase sector */
    	size_t erase_len;	/* whole area that can be erased - may include
    				   bad blocks */
    	size_t erasesize;	/* erase / write length - one block on NAND,
    				   whole area on NOR */
    	size_t processed = 0;	/* progress counter */
    	size_t write_total;	/* total size to actually write - excludinig
    				   bad blocks */
    	off_t erase_offset;	/* offset to the first erase block (aligned)
    				   below offset */
    	off_t block_seek;	/* offset inside the erase block to the start
    				   of the data */
    	off_t top_of_range;	/* end of the last block we may use */
    	loff_t blockstart;	/* running start of the current block -
    				   MEMGETBADBLOCK needs 64 bits */
    	int rc;
    
    	blocklen = DEVESIZE (dev);
    
    	/* Erase sector size is always a power of 2 */
    	top_of_range = (DEVOFFSET (dev) & ~(blocklen - 1)) +
    		ENVSECTORS (dev) * blocklen;
    
    	erase_offset = offset & ~(blocklen - 1);
    
    	/* Maximum area we may use */
    	erase_len = top_of_range - erase_offset;
    
    	blockstart = erase_offset;
    	/* Offset inside a block */
    	block_seek = offset - erase_offset;
    
    	/*
    	 * Data size we actually have to write: from the start of the block
    	 * to the start of the data, then count bytes of data, and to the
    	 * end of the block
    	 */
    	write_total = (block_seek + count + blocklen - 1) & ~(blocklen - 1);
    
    	/*
    	 * Support data anywhere within erase sectors: read out the complete
    	 * area to be erased, replace the environment image, write the whole
    	 * block back again.
    	 */
    	if (write_total > count) {
    		data = malloc (erase_len);
    		if (!data) {
    
    				 "Cannot malloc %u bytes: %s\n",
    				 erase_len, strerror (errno));
    			return -1;
    
    
    		rc = flash_read_buf (dev, fd, data, write_total, erase_offset,
    				     mtd_type);
    		if (write_total != rc)
    			return -1;
    
    		/* Overwrite the old environment */
    		memcpy (data + block_seek, buf, count);
    	} else {
    		/*
    		 * We get here, iff offset is block-aligned and count is a
    		 * multiple of blocklen - see write_total calculation above
    		 */
    		data = buf;
    	}
    
    	if (mtd_type == MTD_NANDFLASH) {
    		/*
    		 * NAND: calculate which blocks we are writing. We have
    		 * to write one block at a time to skip bad blocks.
    		 */
    		erasesize = blocklen;
    	} else {
    		erasesize = erase_len;
    	}
    
    	erase.length = erasesize;
    
    	/* This only runs once on NOR flash */
    	while (processed < write_total) {
    		rc = flash_bad_block (fd, mtd_type, &blockstart);
    		if (rc < 0)		/* block test failed */
    			return rc;
    
    		if (blockstart + erasesize > top_of_range) {
    			fprintf (stderr, "End of range reached, aborting\n");
    			return -1;
    
    
    		if (rc) {		/* block is bad */
    			blockstart += blocklen;
    			continue;
    		}
    
    		erase.start = blockstart;
    		ioctl (fd, MEMUNLOCK, &erase);
    
    		if (ioctl (fd, MEMERASE, &erase) != 0) {
    			fprintf (stderr, "MTD erase error on %s: %s\n",
    				 DEVNAME (dev),
    				 strerror (errno));
    			return -1;
    		}
    
    		if (lseek (fd, blockstart, SEEK_SET) == -1) {
    
    				 "Seek error on %s: %s\n",
    				 DEVNAME (dev), strerror (errno));
    			return -1;
    
    
    #ifdef DEBUG
    		printf ("Write 0x%x bytes at 0x%llx\n", erasesize, blockstart);
    #endif
    		if (write (fd, data + processed, erasesize) != erasesize) {
    			fprintf (stderr, "Write error on %s: %s\n",
    				 DEVNAME (dev), strerror (errno));
    			return -1;
    
    
    		ioctl (fd, MEMLOCK, &erase);
    
    		processed  += blocklen;
    		block_seek = 0;
    		blockstart += blocklen;
    	}
    
    	if (write_total > count)
    		free (data);
    
    	return processed;
    }
    
    /*
     * Set obsolete flag at offset - NOR flash only
     */
    static int flash_flag_obsolete (int dev, int fd, off_t offset)
    {
    	int rc;
    
    	/* This relies on the fact, that obsolete_flag == 0 */
    	rc = lseek (fd, offset, SEEK_SET);
    	if (rc < 0) {
    		fprintf (stderr, "Cannot seek to set the flag on %s \n",
    			 DEVNAME (dev));
    		return rc;
    	}
    	rc = write (fd, &obsolete_flag, sizeof (obsolete_flag));
    	if (rc < 0)
    		perror ("Could not set obsolete flag");
    
    	return rc;
    }
    
    static int flash_write (int fd_current, int fd_target, int dev_target)
    {
    	int rc;
    
    	switch (environment.flag_scheme) {
    	case FLAG_NONE:
    		break;
    	case FLAG_INCREMENTAL:
    		(*environment.flags)++;
    		break;
    	case FLAG_BOOLEAN:
    		*environment.flags = active_flag;
    		break;
    	default:
    		fprintf (stderr, "Unimplemented flash scheme %u \n",
    			 environment.flag_scheme);
    		return -1;
    	}
    
    #ifdef DEBUG
    	printf ("Writing new environment at 0x%lx on %s\n",
    		DEVOFFSET (dev_target), DEVNAME (dev_target));
    #endif
    	rc = flash_write_buf (dev_target, fd_target, environment.image,
    			      CFG_ENV_SIZE, DEVOFFSET (dev_target),
    			      DEVTYPE(dev_target));
    	if (rc < 0)
    		return rc;
    
    	if (environment.flag_scheme == FLAG_BOOLEAN) {
    		/* Have to set obsolete flag */
    		off_t offset = DEVOFFSET (dev_current) +
    			offsetof (struct env_image_redundant, flags);
    #ifdef DEBUG
    		printf ("Setting obsolete flag in environment at 0x%lx on %s\n",
    			DEVOFFSET (dev_current), DEVNAME (dev_current));
    #endif
    		flash_flag_obsolete (dev_current, fd_current, offset);
    	}
    
    	return 0;
    }
    
    static int flash_read (int fd)
    {
    	struct mtd_info_user mtdinfo;
    	int rc;
    
    	rc = ioctl (fd, MEMGETINFO, &mtdinfo);
    	if (rc < 0) {
    		perror ("Cannot get MTD information");
    		return -1;
    	}
    
    	if (mtdinfo.type != MTD_NORFLASH && mtdinfo.type != MTD_NANDFLASH) {
    		fprintf (stderr, "Unsupported flash type %u\n", mtdinfo.type);
    		return -1;
    	}
    
    	DEVTYPE(dev_current) = mtdinfo.type;
    
    	rc = flash_read_buf (dev_current, fd, environment.image, CFG_ENV_SIZE,
    			     DEVOFFSET (dev_current), mtdinfo.type);
    
    	return (rc != CFG_ENV_SIZE) ? -1 : 0;
    }
    
    static int flash_io (int mode)
    {
    	int fd_current, fd_target, rc, dev_target;
    
    	/* dev_current: fd_current, erase_current */
    	fd_current = open (DEVNAME (dev_current), mode);
    	if (fd_current < 0) {
    		fprintf (stderr,
    			 "Can't open %s: %s\n",
    			 DEVNAME (dev_current), strerror (errno));
    		return -1;
    	}
    
    	if (mode == O_RDWR) {
    
    			/* switch to next partition for writing */
    			dev_target = !dev_current;
    			/* dev_target: fd_target, erase_target */
    			fd_target = open (DEVNAME (dev_target), mode);
    			if (fd_target < 0) {
    
    					 "Can't open %s: %s\n",
    					 DEVNAME (dev_target),
    					 strerror (errno));
    				rc = -1;
    				goto exit;
    
    		} else {
    			dev_target = dev_current;
    			fd_target = fd_current;
    
    
    		rc = flash_write (fd_current, fd_target, dev_target);
    
    
    			if (close (fd_target)) {
    
    					"I/O error on %s: %s\n",
    
    					DEVNAME (dev_target),
    
    					strerror (errno));
    
    				rc = -1;
    
    		rc = flash_read (fd_current);
    
    exit:
    	if (close (fd_current)) {
    
    			 "I/O error on %s: %s\n",
    			 DEVNAME (dev_current), strerror (errno));
    		return -1;
    
    	return rc;
    
    }
    
    /*
     * 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)
    
    {
    
    	while (*s1 == *s2++)
    		if (*s1++ == '=')
    
    			return s2;
    
    	if (*s1 == '\0' && *(s2 - 1) == '=')
    
    		return s2;
    	return NULL;
    
    }
    
    /*
     * Prevent confusion if running from erased flash memory
     */
    
    static int env_init (void)
    
    	int crc0, crc0_ok;
    	char flag0;
    	void *addr0;
    
    
    	char flag1;
    	void *addr1;
    
    	struct env_image_single *single;
    	struct env_image_redundant *redundant;
    
    	if (parse_config ())		/* should fill envdevices */
    
    		return -1;
    
    	addr0 = calloc (1, CFG_ENV_SIZE);
    	if (addr0 == NULL) {
    
    		fprintf (stderr,
    			"Not enough memory for environment (%ld bytes)\n",
    
    			CFG_ENV_SIZE);
    		return -1;
    
    	/* read environment from FLASH to local buffer */
    
    	environment.image = addr0;
    
    	if (HaveRedundEnv) {
    		redundant = addr0;
    		environment.crc		= &redundant->crc;
    		environment.flags	= &redundant->flags;
    		environment.data	= redundant->data;
    	} else {
    		single = addr0;
    		environment.crc		= &single->crc;
    		environment.flags	= NULL;
    		environment.data	= single->data;
    
    	dev_current = 0;
    	if (flash_io (O_RDONLY))
    		return -1;
    
    	crc0 = crc32 (0, (uint8_t *) environment.data, ENV_SIZE);
    	crc0_ok = (crc0 == *environment.crc);
    
    		if (!crc0_ok) {
    
    			fprintf (stderr,
    				"Warning: Bad CRC, using default environment\n");
    
    			memcpy(environment.data, default_environment, sizeof default_environment);
    
    		flag0 = *environment.flags;
    
    		dev_current = 1;
    		addr1 = calloc (1, CFG_ENV_SIZE);
    		if (addr1 == NULL) {
    
    			fprintf (stderr,
    				"Not enough memory for environment (%ld bytes)\n",
    
    				CFG_ENV_SIZE);
    			return -1;
    
    		redundant = addr1;
    
    		/*
    		 * have to set environment.image for flash_read(), careful -
    		 * other pointers in environment still point inside addr0
    		 */
    		environment.image = addr1;
    		if (flash_io (O_RDONLY))
    			return -1;
    
    		/* Check flag scheme compatibility */
    		if (DEVTYPE(dev_current) == MTD_NORFLASH &&
    		    DEVTYPE(!dev_current) == MTD_NORFLASH) {
    			environment.flag_scheme = FLAG_BOOLEAN;
    		} else if (DEVTYPE(dev_current) == MTD_NANDFLASH &&
    			   DEVTYPE(!dev_current) == MTD_NANDFLASH) {
    			environment.flag_scheme = FLAG_INCREMENTAL;
    		} else {
    			fprintf (stderr, "Incompatible flash types!\n");
    			return -1;
    
    		crc1 = crc32 (0, (uint8_t *) redundant->data, ENV_SIZE);
    		crc1_ok = (crc1 == redundant->crc);
    		flag1 = redundant->flags;
    
    		if (crc0_ok && !crc1_ok) {
    			dev_current = 0;
    		} else if (!crc0_ok && crc1_ok) {
    			dev_current = 1;
    		} else if (!crc0_ok && !crc1_ok) {
    
    			fprintf (stderr,
    				"Warning: Bad CRC, using default environment\n");
    
    			memcpy (environment.data, default_environment,
    				sizeof default_environment);
    			dev_current = 0;
    		} else {
    			switch (environment.flag_scheme) {
    			case FLAG_BOOLEAN:
    				if (flag0 == active_flag &&
    				    flag1 == obsolete_flag) {
    					dev_current = 0;
    				} else if (flag0 == obsolete_flag &&
    					   flag1 == active_flag) {
    					dev_current = 1;
    				} else if (flag0 == flag1) {
    					dev_current = 0;
    				} else if (flag0 == 0xFF) {
    					dev_current = 0;
    				} else if (flag1 == 0xFF) {
    					dev_current = 1;
    				} else {
    					dev_current = 0;
    				}
    				break;
    			case FLAG_INCREMENTAL:
    				if ((flag0 == 255 && flag1 == 0) ||
    				    flag1 > flag0)
    					dev_current = 1;
    				else if ((flag1 == 255 && flag0 == 0) ||
    					 flag0 > flag1)
    					dev_current = 0;