/*
   * (C) Copyright 2000-2010
   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   *
   * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   * Andreas Heppel <aheppel@sysgo.de>
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <common.h>
  #include <command.h>
  #include <environment.h>
  #include <linux/stddef.h>
  #include <search.h>
  #include <errno.h>
  #include <malloc.h>
  
  DECLARE_GLOBAL_DATA_PTR;
  
  /************************************************************************
   * Default settings to be used when no valid environment is found
   */
  #include <env_default.h>
  
  struct hsearch_data env_htab = {
  	.change_ok = env_flags_validate,
  };
  
  __weak uchar env_get_char_spec(int index)
  {
  	return *((uchar *)(gd->env_addr + index));
  }
  
  static uchar env_get_char_init(int index)
  {
  	/* if crc was bad, use the default environment */
  	if (gd->env_valid)
  		return env_get_char_spec(index);
  	else
  		return default_environment[index];
  }
  
  uchar env_get_char_memory(int index)
  {
  	return *env_get_addr(index);
  }
  
  uchar env_get_char(int index)
  {
  	/* if relocated to RAM */
  	if (gd->flags & GD_FLG_RELOC)
  		return env_get_char_memory(index);
  	else
  		return env_get_char_init(index);
  }
  
  const uchar *env_get_addr(int index)
  {
  	if (gd->env_valid)
  		return (uchar *)(gd->env_addr + index);
  	else
  		return &default_environment[index];
  }
  
  /*
   * Read an environment variable as a boolean
   * Return -1 if variable does not exist (default to true)
   */
  int getenv_yesno(const char *var)
  {
  	char *s = getenv(var);
  
  	if (s == NULL)
  		return -1;
  	return (*s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T') ?
  		1 : 0;
  }
  
  /*
   * Look up the variable from the default environment
   */
  char *getenv_default(const char *name)
  {
  	char *ret_val;
  	unsigned long really_valid = gd->env_valid;
  	unsigned long real_gd_flags = gd->flags;
  
  	/* Pretend that the image is bad. */
  	gd->flags &= ~GD_FLG_ENV_READY;
  	gd->env_valid = 0;
  	ret_val = getenv(name);
  	gd->env_valid = really_valid;
  	gd->flags = real_gd_flags;
  	return ret_val;
  }
  
  void set_default_env(const char *s)
  {
  	int flags = 0;
  
  	if (sizeof(default_environment) > ENV_SIZE) {
  		puts("*** Error - default environment is too large
  
  ");
  		return;
  	}
  
  	if (s) {
  		if (*s == '!') {
  			printf("*** Warning - %s, "
  				"using default environment
  
  ",
  				s + 1);
  		} else {
  			flags = H_INTERACTIVE;
  			puts(s);
  		}
  	} else {
  		puts("Using default environment
  
  ");
  	}
  
  	if (himport_r(&env_htab, (char *)default_environment,
  			sizeof(default_environment), '\0', flags, 0,
  			0, NULL) == 0)
  		error("Environment import failed: errno = %d
  ", errno);
  
  	gd->flags |= GD_FLG_ENV_READY;
  }
  
  
  /* [re]set individual variables to their value in the default environment */
  int set_default_vars(int nvars, char * const vars[])
  {
  	/*
  	 * Special use-case: import from default environment
  	 * (and use \0 as a separator)
  	 */
  	return himport_r(&env_htab, (const char *)default_environment,
  				sizeof(default_environment), '\0',
  				H_NOCLEAR | H_INTERACTIVE, 0, nvars, vars);
  }
  
  #ifdef CONFIG_ENV_AES
  #include <aes.h>
  /**
   * env_aes_cbc_get_key() - Get AES-128-CBC key for the environment
   *
   * This function shall return 16-byte array containing AES-128 key used
   * to encrypt and decrypt the environment. This function must be overriden
   * by the implementer as otherwise the environment encryption will not
   * work.
   */
  __weak uint8_t *env_aes_cbc_get_key(void)
  {
  	return NULL;
  }
  
  static int env_aes_cbc_crypt(env_t *env, const int enc)
  {
  	unsigned char *data = env->data;
  	uint8_t *key;
  	uint8_t key_exp[AES_EXPAND_KEY_LENGTH];
  	uint32_t aes_blocks;
  
  	key = env_aes_cbc_get_key();
  	if (!key)
  		return -EINVAL;
  
  	/* First we expand the key. */
  	aes_expand_key(key, key_exp);
  
  	/* Calculate the number of AES blocks to encrypt. */
  	aes_blocks = ENV_SIZE / AES_KEY_LENGTH;
  
  	if (enc)
  		aes_cbc_encrypt_blocks(key_exp, data, data, aes_blocks);
  	else
  		aes_cbc_decrypt_blocks(key_exp, data, data, aes_blocks);
  
  	return 0;
  }
  #else
  static inline int env_aes_cbc_crypt(env_t *env, const int enc)
  {
  	return 0;
  }
  #endif
  
  /*
   * Check if CRC is valid and (if yes) import the environment.
   * Note that "buf" may or may not be aligned.
   */
  int env_import(const char *buf, int check)
  {
  	env_t *ep = (env_t *)buf;
  	int ret;
  
  	if (check) {
  		uint32_t crc;
  
  		memcpy(&crc, &ep->crc, sizeof(crc));
  
  		if (crc32(0, ep->data, ENV_SIZE) != crc) {
  			set_default_env("!bad CRC");
  			return 0;
  		}
  	}
  
  	/* Decrypt the env if desired. */
  	ret = env_aes_cbc_crypt(ep, 0);
  	if (ret) {
  		error("Failed to decrypt env!
  ");
  		set_default_env("!import failed");
  		return ret;
  	}
  
  	if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
  			0, NULL)) {
  		gd->flags |= GD_FLG_ENV_READY;
  		return 1;
  	}
  
  	error("Cannot import environment: errno = %d
  ", errno);
  
  	set_default_env("!import failed");
  
  	return 0;
  }
  
  /* Emport the environment and generate CRC for it. */
  int env_export(env_t *env_out)
  {
  	char *res;
  	ssize_t	len;
  	int ret;
  
  	res = (char *)env_out->data;
  	len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
  	if (len < 0) {
  		error("Cannot export environment: errno = %d
  ", errno);
  		return 1;
  	}
  
  	/* Encrypt the env if desired. */
  	ret = env_aes_cbc_crypt(env_out, 1);
  	if (ret)
  		return ret;
  
  	env_out->crc = crc32(0, env_out->data, ENV_SIZE);
  
  	return 0;
  }
  
  void env_relocate(void)
  {
  #if defined(CONFIG_NEEDS_MANUAL_RELOC)
  	env_reloc();
  	env_htab.change_ok += gd->reloc_off;
  #endif
  	if (gd->env_valid == 0) {
  #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
  		/* Environment not changable */
  		set_default_env(NULL);
  #else
  		bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
  		set_default_env("!bad CRC");
  #endif
  	} else {
  		env_relocate_spec();
  	}
  }
  
  #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
  int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
  {
  	ENTRY *match;
  	int found, idx;
  
  	idx = 0;
  	found = 0;
  	cmdv[0] = NULL;
  
  	while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
  		int vallen = strlen(match->key) + 1;
  
  		if (found >= maxv - 2 || bufsz < vallen)
  			break;
  
  		cmdv[found++] = buf;
  		memcpy(buf, match->key, vallen);
  		buf += vallen;
  		bufsz -= vallen;
  	}
  
  	qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
  
  	if (idx)
  		cmdv[found++] = "...";
  
  	cmdv[found] = NULL;
  	return found;
  }
  #endif