/*
   * This implementation is based on code from uClibc-0.9.30.3 but was
   * modified and extended for use within U-Boot.
   *

   * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>

   *
   * Original license header:
   *
   * Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
   * This file is part of the GNU C Library.
   * Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1993.
   *

   * SPDX-License-Identifier:	LGPL-2.1+

   */
  
  #include <errno.h>
  #include <malloc.h>
  
  #ifdef USE_HOSTCC		/* HOST build */
  # include <string.h>
  # include <assert.h>

  # include <ctype.h>

  
  # ifndef debug
  #  ifdef DEBUG
  #   define debug(fmt,args...)	printf(fmt ,##args)
  #  else
  #   define debug(fmt,args...)
  #  endif
  # endif
  #else				/* U-Boot build */
  # include <common.h>
  # include <linux/string.h>

  # include <linux/ctype.h>

  #endif

  #ifndef	CONFIG_ENV_MIN_ENTRIES	/* minimum number of entries */
  #define	CONFIG_ENV_MIN_ENTRIES 64
  #endif

  #ifndef	CONFIG_ENV_MAX_ENTRIES	/* maximum number of entries */
  #define	CONFIG_ENV_MAX_ENTRIES 512
  #endif

  #include <env_callback.h>

  #include <env_flags.h>

  #include <search.h>

  #include <slre.h>

  
  /*
   * [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986

   * [Knuth]	      The Art of Computer Programming, part 3 (6.4)

   */
  
  /*

   * The reentrant version has no static variables to maintain the state.
   * Instead the interface of all functions is extended to take an argument
   * which describes the current status.
   */

  typedef struct _ENTRY {

  	int used;

  	ENTRY entry;
  } _ENTRY;

  static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
  	int idx);

  /*
   * hcreate()
   */
  
  /*
   * For the used double hash method the table size has to be a prime. To
   * correct the user given table size we need a prime test.  This trivial
   * algorithm is adequate because
   * a)  the code is (most probably) called a few times per program run and
   * b)  the number is small because the table must fit in the core
   * */
  static int isprime(unsigned int number)
  {
  	/* no even number will be passed */
  	unsigned int div = 3;
  
  	while (div * div < number && number % div != 0)
  		div += 2;
  
  	return number % div != 0;
  }

  /*
   * Before using the hash table we must allocate memory for it.
   * Test for an existing table are done. We allocate one element
   * more as the found prime number says. This is done for more effective
   * indexing as explained in the comment for the hsearch function.
   * The contents of the table is zeroed, especially the field used
   * becomes zero.
   */

  int hcreate_r(size_t nel, struct hsearch_data *htab)
  {
  	/* Test for correct arguments.  */
  	if (htab == NULL) {
  		__set_errno(EINVAL);
  		return 0;
  	}
  
  	/* There is still another table active. Return with error. */
  	if (htab->table != NULL)
  		return 0;
  
  	/* Change nel to the first prime number not smaller as nel. */
  	nel |= 1;		/* make odd */
  	while (!isprime(nel))
  		nel += 2;
  
  	htab->size = nel;
  	htab->filled = 0;
  
  	/* allocate memory and zero out */
  	htab->table = (_ENTRY *) calloc(htab->size + 1, sizeof(_ENTRY));
  	if (htab->table == NULL)
  		return 0;
  
  	/* everything went alright */
  	return 1;
  }
  
  
  /*
   * hdestroy()
   */

  
  /*
   * After using the hash table it has to be destroyed. The used memory can
   * be freed and the local static variable can be marked as not used.
   */

  void hdestroy_r(struct hsearch_data *htab)

  {
  	int i;
  
  	/* Test for correct arguments.  */
  	if (htab == NULL) {
  		__set_errno(EINVAL);
  		return;
  	}
  
  	/* free used memory */
  	for (i = 1; i <= htab->size; ++i) {

  		if (htab->table[i].used > 0) {

  			ENTRY *ep = &htab->table[i].entry;

  			free((void *)ep->key);

  			free(ep->data);
  		}
  	}
  	free(htab->table);
  
  	/* the sign for an existing table is an value != NULL in htable */
  	htab->table = NULL;
  }
  
  /*
   * hsearch()
   */
  
  /*
   * This is the search function. It uses double hashing with open addressing.
   * The argument item.key has to be a pointer to an zero terminated, most
   * probably strings of chars. The function for generating a number of the
   * strings is simple but fast. It can be replaced by a more complex function
   * like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
   *
   * We use an trick to speed up the lookup. The table is created by hcreate
   * with one more element available. This enables us to use the index zero
   * special. This index will never be used because we store the first hash
   * index in the field used where zero means not used. Every other value
   * means used. The used field can be used as a first fast comparison for
   * equality of the stored and the parameter value. This helps to prevent
   * unnecessary expensive calls of strcmp.
   *
   * This implementation differs from the standard library version of
   * this function in a number of ways:
   *
   * - While the standard version does not make any assumptions about
   *   the type of the stored data objects at all, this implementation
   *   works with NUL terminated strings only.
   * - Instead of storing just pointers to the original objects, we
   *   create local copies so the caller does not need to care about the
   *   data any more.
   * - The standard implementation does not provide a way to update an
   *   existing entry.  This version will create a new entry or update an
   *   existing one when both "action == ENTER" and "item.data != NULL".
   * - Instead of returning 1 on success, we return the index into the
   *   internal hash table, which is also guaranteed to be positive.
   *   This allows us direct access to the found hash table slot for
   *   example for functions like hdelete().
   */

  int hmatch_r(const char *match, int last_idx, ENTRY ** retval,
  	     struct hsearch_data *htab)
  {
  	unsigned int idx;
  	size_t key_len = strlen(match);
  
  	for (idx = last_idx + 1; idx < htab->size; ++idx) {

  		if (htab->table[idx].used <= 0)

  			continue;
  		if (!strncmp(match, htab->table[idx].entry.key, key_len)) {
  			*retval = &htab->table[idx].entry;
  			return idx;
  		}
  	}
  
  	__set_errno(ESRCH);
  	*retval = NULL;
  	return 0;
  }

  /*
   * Compare an existing entry with the desired key, and overwrite if the action
   * is ENTER.  This is simply a helper function for hsearch_r().
   */
  static inline int _compare_and_overwrite_entry(ENTRY item, ACTION action,
  	ENTRY **retval, struct hsearch_data *htab, int flag,
  	unsigned int hval, unsigned int idx)
  {
  	if (htab->table[idx].used == hval
  	    && strcmp(item.key, htab->table[idx].entry.key) == 0) {
  		/* Overwrite existing value? */
  		if ((action == ENTER) && (item.data != NULL)) {

  			/* check for permission */
  			if (htab->change_ok != NULL && htab->change_ok(
  			    &htab->table[idx].entry, item.data,
  			    env_op_overwrite, flag)) {
  				debug("change_ok() rejected setting variable "
  					"%s, skipping it!
  ", item.key);
  				__set_errno(EPERM);
  				*retval = NULL;
  				return 0;
  			}

  			/* If there is a callback, call it */
  			if (htab->table[idx].entry.callback &&
  			    htab->table[idx].entry.callback(item.key,
  			    item.data, env_op_overwrite, flag)) {
  				debug("callback() rejected setting variable "
  					"%s, skipping it!
  ", item.key);
  				__set_errno(EINVAL);
  				*retval = NULL;
  				return 0;
  			}

  			free(htab->table[idx].entry.data);
  			htab->table[idx].entry.data = strdup(item.data);
  			if (!htab->table[idx].entry.data) {
  				__set_errno(ENOMEM);
  				*retval = NULL;
  				return 0;
  			}
  		}
  		/* return found entry */
  		*retval = &htab->table[idx].entry;
  		return idx;
  	}
  	/* keep searching */
  	return -1;
  }

  int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval,

  	      struct hsearch_data *htab, int flag)

  {
  	unsigned int hval;
  	unsigned int count;
  	unsigned int len = strlen(item.key);
  	unsigned int idx;

  	unsigned int first_deleted = 0;

  	int ret;

  
  	/* Compute an value for the given string. Perhaps use a better method. */
  	hval = len;
  	count = len;
  	while (count-- > 0) {
  		hval <<= 4;
  		hval += item.key[count];
  	}
  
  	/*
  	 * First hash function:
  	 * simply take the modul but prevent zero.
  	 */
  	hval %= htab->size;
  	if (hval == 0)
  		++hval;
  
  	/* The first index tried. */
  	idx = hval;
  
  	if (htab->table[idx].used) {
  		/*

  		 * Further action might be required according to the

  		 * action value.
  		 */
  		unsigned hval2;

  		if (htab->table[idx].used == -1
  		    && !first_deleted)
  			first_deleted = idx;

  		ret = _compare_and_overwrite_entry(item, action, retval, htab,
  			flag, hval, idx);
  		if (ret != -1)
  			return ret;

  
  		/*
  		 * Second hash function:
  		 * as suggested in [Knuth]
  		 */
  		hval2 = 1 + hval % (htab->size - 2);
  
  		do {
  			/*

  			 * Because SIZE is prime this guarantees to
  			 * step through all available indices.

  			 */
  			if (idx <= hval2)
  				idx = htab->size + idx - hval2;
  			else
  				idx -= hval2;
  
  			/*
  			 * If we visited all entries leave the loop
  			 * unsuccessfully.
  			 */
  			if (idx == hval)
  				break;
  
  			/* If entry is found use it. */

  			ret = _compare_and_overwrite_entry(item, action, retval,
  				htab, flag, hval, idx);
  			if (ret != -1)
  				return ret;

  		}
  		while (htab->table[idx].used);
  	}
  
  	/* An empty bucket has been found. */
  	if (action == ENTER) {
  		/*

  		 * If table is full and another entry should be
  		 * entered return with error.

  		 */
  		if (htab->filled == htab->size) {
  			__set_errno(ENOMEM);
  			*retval = NULL;
  			return 0;
  		}
  
  		/*
  		 * Create new entry;
  		 * create copies of item.key and item.data
  		 */

  		if (first_deleted)
  			idx = first_deleted;

  		htab->table[idx].used = hval;
  		htab->table[idx].entry.key = strdup(item.key);
  		htab->table[idx].entry.data = strdup(item.data);
  		if (!htab->table[idx].entry.key ||
  		    !htab->table[idx].entry.data) {
  			__set_errno(ENOMEM);
  			*retval = NULL;
  			return 0;
  		}
  
  		++htab->filled;

  		/* This is a new entry, so look up a possible callback */
  		env_callback_init(&htab->table[idx].entry);

  		/* Also look for flags */
  		env_flags_init(&htab->table[idx].entry);

  		/* check for permission */
  		if (htab->change_ok != NULL && htab->change_ok(
  		    &htab->table[idx].entry, item.data, env_op_create, flag)) {
  			debug("change_ok() rejected setting variable "
  				"%s, skipping it!
  ", item.key);
  			_hdelete(item.key, htab, &htab->table[idx].entry, idx);
  			__set_errno(EPERM);
  			*retval = NULL;
  			return 0;
  		}

  		/* If there is a callback, call it */
  		if (htab->table[idx].entry.callback &&
  		    htab->table[idx].entry.callback(item.key, item.data,
  		    env_op_create, flag)) {
  			debug("callback() rejected setting variable "
  				"%s, skipping it!
  ", item.key);
  			_hdelete(item.key, htab, &htab->table[idx].entry, idx);
  			__set_errno(EINVAL);
  			*retval = NULL;
  			return 0;
  		}

  		/* return new entry */
  		*retval = &htab->table[idx].entry;
  		return 1;
  	}
  
  	__set_errno(ESRCH);
  	*retval = NULL;
  	return 0;
  }
  
  
  /*
   * hdelete()
   */
  
  /*
   * The standard implementation of hsearch(3) does not provide any way
   * to delete any entries from the hash table.  We extend the code to
   * do that.
   */

  static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
  	int idx)
  {
  	/* free used ENTRY */
  	debug("hdelete: DELETING key \"%s\"
  ", key);
  	free((void *)ep->key);
  	free(ep->data);

  	ep->callback = NULL;

  	ep->flags = 0;

  	htab->table[idx].used = -1;
  
  	--htab->filled;
  }

  int hdelete_r(const char *key, struct hsearch_data *htab, int flag)

  {
  	ENTRY e, *ep;
  	int idx;
  
  	debug("hdelete: DELETE key \"%s\"
  ", key);
  
  	e.key = (char *)key;

  	idx = hsearch_r(e, FIND, &ep, htab, 0);
  	if (idx == 0) {

  		__set_errno(ESRCH);
  		return 0;	/* not found */
  	}

  	/* Check for permission */

  	if (htab->change_ok != NULL &&
  	    htab->change_ok(ep, NULL, env_op_delete, flag)) {
  		debug("change_ok() rejected deleting variable "
  			"%s, skipping it!
  ", key);

  		__set_errno(EPERM);
  		return 0;
  	}

  	/* If there is a callback, call it */
  	if (htab->table[idx].entry.callback &&
  	    htab->table[idx].entry.callback(key, NULL, env_op_delete, flag)) {
  		debug("callback() rejected deleting variable "
  			"%s, skipping it!
  ", key);
  		__set_errno(EINVAL);
  		return 0;
  	}

  	_hdelete(key, htab, ep, idx);

  
  	return 1;
  }
  
  /*
   * hexport()
   */

  #ifndef CONFIG_SPL_BUILD

  /*
   * Export the data stored in the hash table in linearized form.
   *
   * Entries are exported as "name=value" strings, separated by an
   * arbitrary (non-NUL, of course) separator character. This allows to
   * use this function both when formatting the U-Boot environment for
   * external storage (using '\0' as separator), but also when using it
   * for the "printenv" command to print all variables, simply by using
   * as '
  " as separator. This can also be used for new features like
   * exporting the environment data as text file, including the option
   * for later re-import.
   *
   * The entries in the result list will be sorted by ascending key
   * values.
   *
   * If the separator character is different from NUL, then any
   * separator characters and backslash characters in the values will
   * be escaped by a preceeding backslash in output. This is needed for
   * example to enable multi-line values, especially when the output
   * shall later be parsed (for example, for re-import).
   *
   * There are several options how the result buffer is handled:
   *
   * *resp  size
   * -----------
   *  NULL    0	A string of sufficient length will be allocated.
   *  NULL   >0	A string of the size given will be
   *		allocated. An error will be returned if the size is
   *		not sufficient.  Any unused bytes in the string will
   *		be '\0'-padded.
   * !NULL    0	The user-supplied buffer will be used. No length
   *		checking will be performed, i. e. it is assumed that
   *		the buffer size will always be big enough. DANGEROUS.
   * !NULL   >0	The user-supplied buffer will be used. An error will
   *		be returned if the size is not sufficient.  Any unused
   *		bytes in the string will be '\0'-padded.
   */

  static int cmpkey(const void *p1, const void *p2)
  {
  	ENTRY *e1 = *(ENTRY **) p1;
  	ENTRY *e2 = *(ENTRY **) p2;
  
  	return (strcmp(e1->key, e2->key));
  }

  static int match_string(int flag, const char *str, const char *pat, void *priv)

  {
  	switch (flag & H_MATCH_METHOD) {
  	case H_MATCH_IDENT:
  		if (strcmp(str, pat) == 0)
  			return 1;
  		break;
  	case H_MATCH_SUBSTR:
  		if (strstr(str, pat))
  			return 1;
  		break;

  #ifdef CONFIG_REGEX
  	case H_MATCH_REGEX:
  		{
  			struct slre *slrep = (struct slre *)priv;
  			struct cap caps[slrep->num_caps + 2];
  
  			if (slre_match(slrep, str, strlen(str), caps))
  				return 1;
  		}
  		break;
  #endif

  	default:
  		printf("## ERROR: unsupported match method: 0x%02x
  ",
  			flag & H_MATCH_METHOD);
  		break;
  	}
  	return 0;
  }
  
  static int match_entry(ENTRY *ep, int flag,

  		 int argc, char * const argv[])
  {
  	int arg;

  	void *priv = NULL;

  	for (arg = 0; arg < argc; ++arg) {

  #ifdef CONFIG_REGEX
  		struct slre slre;
  
  		if (slre_compile(&slre, argv[arg]) == 0) {
  			printf("Error compiling regex: %s
  ", slre.err_str);
  			return 0;
  		}
  
  		priv = (void *)&slre;
  #endif

  		if (flag & H_MATCH_KEY) {

  			if (match_string(flag, ep->key, argv[arg], priv))

  				return 1;
  		}
  		if (flag & H_MATCH_DATA) {

  			if (match_string(flag, ep->data, argv[arg], priv))

  				return 1;

  		}
  	}
  	return 0;
  }

  ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,

  		 char **resp, size_t size,
  		 int argc, char * const argv[])

  {
  	ENTRY *list[htab->size];
  	char *res, *p;
  	size_t totlen;
  	int i, n;
  
  	/* Test for correct arguments.  */
  	if ((resp == NULL) || (htab == NULL)) {
  		__set_errno(EINVAL);
  		return (-1);
  	}

  	debug("EXPORT  table = %p, htab.size = %d, htab.filled = %d, "
  		"size = %zu
  ", htab, htab->size, htab->filled, size);

  	/*
  	 * Pass 1:
  	 * search used entries,
  	 * save addresses and compute total length
  	 */
  	for (i = 1, n = 0, totlen = 0; i <= htab->size; ++i) {

  		if (htab->table[i].used > 0) {

  			ENTRY *ep = &htab->table[i].entry;

  			int found = match_entry(ep, flag, argc, argv);

  			if ((argc > 0) && (found == 0))
  				continue;

  			if ((flag & H_HIDE_DOT) && ep->key[0] == '.')
  				continue;

  			list[n++] = ep;
  
  			totlen += strlen(ep->key) + 2;
  
  			if (sep == '\0') {
  				totlen += strlen(ep->data);
  			} else {	/* check if escapes are needed */
  				char *s = ep->data;
  
  				while (*s) {
  					++totlen;
  					/* add room for needed escape chars */
  					if ((*s == sep) || (*s == '\\'))
  						++totlen;
  					++s;
  				}
  			}
  			totlen += 2;	/* for '=' and 'sep' char */
  		}
  	}
  
  #ifdef DEBUG
  	/* Pass 1a: print unsorted list */
  	printf("Unsorted: n=%d
  ", n);
  	for (i = 0; i < n; ++i) {
  		printf("\t%3d: %p ==> %-10s => %s
  ",
  		       i, list[i], list[i]->key, list[i]->data);
  	}
  #endif
  
  	/* Sort list by keys */
  	qsort(list, n, sizeof(ENTRY *), cmpkey);
  
  	/* Check if the user supplied buffer size is sufficient */
  	if (size) {
  		if (size < totlen + 1) {	/* provided buffer too small */

  			printf("Env export buffer too small: %zu, "
  				"but need %zu
  ", size, totlen + 1);

  			__set_errno(ENOMEM);
  			return (-1);
  		}
  	} else {
  		size = totlen + 1;
  	}
  
  	/* Check if the user provided a buffer */
  	if (*resp) {
  		/* yes; clear it */
  		res = *resp;
  		memset(res, '\0', size);
  	} else {
  		/* no, allocate and clear one */
  		*resp = res = calloc(1, size);
  		if (res == NULL) {
  			__set_errno(ENOMEM);
  			return (-1);
  		}
  	}
  	/*
  	 * Pass 2:
  	 * export sorted list of result data
  	 */
  	for (i = 0, p = res; i < n; ++i) {

  		const char *s;

  
  		s = list[i]->key;
  		while (*s)
  			*p++ = *s++;
  		*p++ = '=';
  
  		s = list[i]->data;
  
  		while (*s) {
  			if ((*s == sep) || (*s == '\\'))
  				*p++ = '\\';	/* escape */
  			*p++ = *s++;
  		}
  		*p++ = sep;
  	}
  	*p = '\0';		/* terminate result */
  
  	return size;
  }

  #endif

  
  
  /*
   * himport()
   */

  /*
   * Check whether variable 'name' is amongst vars[],
   * and remove all instances by setting the pointer to NULL
   */
  static int drop_var_from_set(const char *name, int nvars, char * vars[])

  {
  	int i = 0;

  	int res = 0;

  
  	/* No variables specified means process all of them */
  	if (nvars == 0)
  		return 1;
  
  	for (i = 0; i < nvars; i++) {

  		if (vars[i] == NULL)
  			continue;
  		/* If we found it, delete all of them */
  		if (!strcmp(name, vars[i])) {
  			vars[i] = NULL;
  			res = 1;
  		}

  	}

  	if (!res)
  		debug("Skipping non-listed variable %s
  ", name);

  	return res;

  }

  /*
   * Import linearized data into hash table.
   *
   * This is the inverse function to hexport(): it takes a linear list
   * of "name=value" pairs and creates hash table entries from it.
   *
   * Entries without "value", i. e. consisting of only "name" or
   * "name=", will cause this entry to be deleted from the hash table.
   *
   * The "flag" argument can be used to control the behaviour: when the
   * H_NOCLEAR bit is set, then an existing hash table will kept, i. e.
   * new data will be added to an existing hash table; otherwise, old
   * data will be discarded and a new hash table will be created.
   *
   * The separator character for the "name=value" pairs can be selected,
   * so we both support importing from externally stored environment
   * data (separated by NUL characters) and from plain text files
   * (entries separated by newline characters).
   *
   * To allow for nicely formatted text input, leading white space
   * (sequences of SPACE and TAB chars) is ignored, and entries starting
   * (after removal of any leading white space) with a '#' character are
   * considered comments and ignored.
   *
   * [NOTE: this means that a variable name cannot start with a '#'
   * character.]
   *
   * When using a non-NUL separator character, backslash is used as
   * escape character in the value part, allowing for example for
   * multi-line values.
   *
   * In theory, arbitrary separator characters can be used, but only
   * '\0' and '
  ' have really been tested.
   */

  int himport_r(struct hsearch_data *htab,

  		const char *env, size_t size, const char sep, int flag,

  		int nvars, char * const vars[])

  {
  	char *data, *sp, *dp, *name, *value;

  	char *localvars[nvars];
  	int i;

  
  	/* Test for correct arguments.  */
  	if (htab == NULL) {
  		__set_errno(EINVAL);
  		return 0;
  	}
  
  	/* we allocate new space to make sure we can write to the array */
  	if ((data = malloc(size)) == NULL) {

  		debug("himport_r: can't malloc %zu bytes
  ", size);

  		__set_errno(ENOMEM);
  		return 0;
  	}
  	memcpy(data, env, size);
  	dp = data;

  	/* make a local copy of the list of variables */
  	if (nvars)
  		memcpy(localvars, vars, sizeof(vars[0]) * nvars);

  	if ((flag & H_NOCLEAR) == 0) {
  		/* Destroy old hash table if one exists */
  		debug("Destroy Hash Table: %p table = %p
  ", htab,
  		       htab->table);
  		if (htab->table)

  			hdestroy_r(htab);

  	}
  
  	/*
  	 * Create new hash table (if needed).  The computation of the hash
  	 * table size is based on heuristics: in a sample of some 70+
  	 * existing systems we found an average size of 39+ bytes per entry
  	 * in the environment (for the whole key=value pair). Assuming a

  	 * size of 8 per entry (= safety factor of ~5) should provide enough
  	 * safety margin for any existing environment definitions and still

  	 * allow for more than enough dynamic additions. Note that the

  	 * "size" argument is supposed to give the maximum environment size

  	 * (CONFIG_ENV_SIZE).  This heuristics will result in
  	 * unreasonably large numbers (and thus memory footprint) for
  	 * big flash environments (>8,000 entries for 64 KB

  	 * envrionment size), so we clip it to a reasonable value.
  	 * On the other hand we need to add some more entries for free
  	 * space when importing very small buffers. Both boundaries can
  	 * be overwritten in the board config file if needed.

  	 */
  
  	if (!htab->table) {

  		int nent = CONFIG_ENV_MIN_ENTRIES + size / 8;

  
  		if (nent > CONFIG_ENV_MAX_ENTRIES)
  			nent = CONFIG_ENV_MAX_ENTRIES;

  
  		debug("Create Hash Table: N=%d
  ", nent);
  
  		if (hcreate_r(nent, htab) == 0) {
  			free(data);
  			return 0;
  		}
  	}
  
  	/* Parse environment; allow for '\0' and 'sep' as separators */
  	do {
  		ENTRY e, *rv;
  
  		/* skip leading white space */

  		while (isblank(*dp))

  			++dp;
  
  		/* skip comment lines */
  		if (*dp == '#') {
  			while (*dp && (*dp != sep))
  				++dp;
  			++dp;
  			continue;
  		}
  
  		/* parse name */
  		for (name = dp; *dp != '=' && *dp && *dp != sep; ++dp)
  			;
  
  		/* deal with "name" and "name=" entries (delete var) */
  		if (*dp == '\0' || *(dp + 1) == '\0' ||
  		    *dp == sep || *(dp + 1) == sep) {
  			if (*dp == '=')
  				*dp++ = '\0';
  			*dp++ = '\0';	/* terminate name */
  
  			debug("DELETE CANDIDATE: \"%s\"
  ", name);

  			if (!drop_var_from_set(name, nvars, localvars))

  				continue;

  			if (hdelete_r(name, htab, flag) == 0)

  				debug("DELETE ERROR ##############################
  ");
  
  			continue;
  		}
  		*dp++ = '\0';	/* terminate name */
  
  		/* parse value; deal with escapes */
  		for (value = sp = dp; *dp && (*dp != sep); ++dp) {
  			if ((*dp == '\\') && *(dp + 1))
  				++dp;
  			*sp++ = *dp;
  		}
  		*sp++ = '\0';	/* terminate value */
  		++dp;

  		if (*name == 0) {
  			debug("INSERT: unable to use an empty key
  ");
  			__set_errno(EINVAL);
  			return 0;
  		}

  		/* Skip variables which are not supposed to be processed */

  		if (!drop_var_from_set(name, nvars, localvars))

  			continue;

  		/* enter into hash table */
  		e.key = name;
  		e.data = value;

  		hsearch_r(e, ENTER, &rv, htab, flag);

  		if (rv == NULL)

  			printf("himport_r: can't insert \"%s=%s\" into hash table
  ",
  				name, value);

  		debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"
  ",
  			htab, htab->filled, htab->size,
  			rv, name, value);

  	} while ((dp < data + size) && *dp);	/* size check needed for text */
  						/* without '\0' termination */

  	debug("INSERT: free(data = %p)
  ", data);

  	free(data);

  	/* process variables which were not considered */
  	for (i = 0; i < nvars; i++) {
  		if (localvars[i] == NULL)
  			continue;
  		/*
  		 * All variables which were not deleted from the variable list
  		 * were not present in the imported env
  		 * This could mean two things:
  		 * a) if the variable was present in current env, we delete it
  		 * b) if the variable was not present in current env, we notify
  		 *    it might be a typo
  		 */

  		if (hdelete_r(localvars[i], htab, flag) == 0)

  			printf("WARNING: '%s' neither in running nor in imported env!
  ", localvars[i]);
  		else
  			printf("WARNING: '%s' not in imported env, deleting it!
  ", localvars[i]);
  	}

  	debug("INSERT: done
  ");

  	return 1;		/* everything OK */
  }

  
  /*
   * hwalk_r()
   */
  
  /*
   * Walk all of the entries in the hash, calling the callback for each one.
   * this allows some generic operation to be performed on each element.
   */
  int hwalk_r(struct hsearch_data *htab, int (*callback)(ENTRY *))
  {
  	int i;
  	int retval;
  
  	for (i = 1; i <= htab->size; ++i) {
  		if (htab->table[i].used > 0) {
  			retval = callback(&htab->table[i].entry);
  			if (retval)
  				return retval;
  		}
  	}
  
  	return 0;
  }