text: /*
   * (C) Copyright 2002-2008
   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <aes.h>
  #include <stdint.h>
  
  /*
   * To build the utility with the static configuration
   * comment out the next line.
   * See included "fw_env.config" sample file
   * for notes on configuration.
   */
  #define CONFIG_FILE     "/etc/fw_env.config"
  
  #ifndef CONFIG_FILE
  #define HAVE_REDUND /* For systems with 2 env sectors */
  #define DEVICE1_NAME      "/dev/mtd1"
  #define DEVICE2_NAME      "/dev/mtd2"
  #define DEVICE1_OFFSET    0x0000
  #define ENV1_SIZE         0x4000
  #define DEVICE1_ESIZE     0x4000
  #define DEVICE1_ENVSECTORS     2
  #define DEVICE2_OFFSET    0x0000
  #define ENV2_SIZE         0x4000
  #define DEVICE2_ESIZE     0x4000
  #define DEVICE2_ENVSECTORS     2
  #endif
  
  #ifndef CONFIG_BAUDRATE
  #define CONFIG_BAUDRATE		115200
  #endif
  
  #ifndef CONFIG_BOOTDELAY
  #define CONFIG_BOOTDELAY	5	/* autoboot after 5 seconds	*/
  #endif
  
  #ifndef CONFIG_BOOTCOMMAND
  #define CONFIG_BOOTCOMMAND							\
  	"bootp; "								\
  	"setenv bootargs root=/dev/nfs nfsroot=${serverip}:${rootpath} "	\
  	"ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}::off; "	\
  	"bootm"
  #endif
  
  struct env_opts {
  #ifdef CONFIG_FILE
  	char *config_file;
  #endif
  	int aes_flag; /* Is AES encryption used? */
  	uint8_t aes_key[AES_KEY_LENGTH];
  };
  
  int parse_aes_key(char *key, uint8_t *bin_key);
  
  /**
   * fw_printenv() - print one or several environment variables
   *
   * @argc: number of variables names to be printed, prints all if 0
   * @argv: array of variable names to be printed, if argc != 0
   * @value_only: do not repeat the variable name, print the bare value,
   *          only one variable allowed with this option, argc must be 1
   * @opts: encryption key, configuration file, defaults are used if NULL
   *
   * Description:
   *  Uses fw_env_open, fw_getenv
   *
   * Return:
   *  0 on success, -1 on failure (modifies errno)
   */
  int fw_printenv(int argc, char *argv[], int value_only, struct env_opts *opts);
  
  /**
   * fw_setenv() - adds or removes one variable to the environment
   *
   * @argc: number of strings in argv, argv[0] is variable name,
   *          argc==1 means erase variable, argc > 1 means add a variable
   * @argv: argv[0] is variable name, argv[1..argc-1] are concatenated separated
   *           by single blank and set as the new value of the variable
   * @opts: how to retrieve environment from flash, defaults are used if NULL
   *
   * Description:
   *  Uses fw_env_open, fw_env_write, fw_env_close
   *
   * Return:
   *  0 on success, -1 on failure (modifies errno)
   *
   * ERRORS:
   *  EROFS - some variables ("ethaddr", "serial#") cannot be modified
   */
  int fw_setenv(int argc, char *argv[], struct env_opts *opts);
  
  /**
   * fw_parse_script() - adds or removes multiple variables with a batch script
   *
   * @fname: batch script file name
   * @opts: encryption key, configuration file, defaults are used if NULL
   *
   * Description:
   *  Uses fw_env_open, fw_env_write, fw_env_close
   *
   * Return:
   *  0 success, -1 on failure (modifies errno)
   *
   * Script Syntax:
   *
   *  key [ [space]+ value]
   *
   *  lines starting with '#' treated as comment
   *
   *  A variable without value will be deleted. Any number of spaces are allowed
   *  between key and value. The value starts with the first non-space character
   *  and ends with newline. No comments allowed on these lines.  Spaces inside
   *  the value are preserved verbatim.
   *
   * Script Example:
   *
   *  netdev         eth0
   *
   *  kernel_addr    400000
   *
   *  foo            spaces           are copied verbatim
   *
   *  # delete variable bar
   *
   *  bar
   */
  int fw_parse_script(char *fname, struct env_opts *opts);
  
  
  /**
   * fw_env_open() - read enviroment from flash into RAM cache
   *
   * @opts: encryption key, configuration file, defaults are used if NULL
   *
   * Return:
   *  0 on success, -1 on failure (modifies errno)
   */
  int fw_env_open(struct env_opts *opts);
  
  /**
   * fw_getenv() - lookup variable in the RAM cache
   *
   * @name: variable to be searched
   * Return:
   *  pointer to start of value, NULL if not found
   */
  char *fw_getenv(char *name);
  
  /**
   * fw_env_write() - modify a variable held in the RAM cache
   *
   * @name: variable
   * @value: delete variable if NULL, otherwise create or overwrite the variable
   *
   * This is called in sequence to update the environment in RAM without updating
   * the copy in flash after each set
   *
   * Return:
   *  0 on success, -1 on failure (modifies errno)
   *
   * ERRORS:
   *  EROFS - some variables ("ethaddr", "serial#") cannot be modified
   */
  int fw_env_write(char *name, char *value);
  
  /**
   * fw_env_close - write the environment from RAM cache back to flash
   *
   * @opts: encryption key, configuration file, defaults are used if NULL
   *
   * Return:
   *  0 on success, -1 on failure (modifies errno)
   */
  int fw_env_close(struct env_opts *opts);
  
  unsigned long crc32(unsigned long, const unsigned char *, unsigned);
  