xref: /rk3399_rockchip-uboot/lib/hashtable.c (revision 7afcf3a55b5f484b3d3442053fae8186a3fb92d7)
1 /*
2  * This implementation is based on code from uClibc-0.9.30.3 but was
3  * modified and extended for use within U-Boot.
4  *
5  * Copyright (C) 2010 Wolfgang Denk <wd@denx.de>
6  *
7  * Original license header:
8  *
9  * Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
10  * This file is part of the GNU C Library.
11  * Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1993.
12  *
13  * The GNU C Library is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU Lesser General Public
15  * License as published by the Free Software Foundation; either
16  * version 2.1 of the License, or (at your option) any later version.
17  *
18  * The GNU C Library is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  * Lesser General Public License for more details.
22  *
23  * You should have received a copy of the GNU Lesser General Public
24  * License along with the GNU C Library; if not, write to the Free
25  * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26  * 02111-1307 USA.
27  */
28 
29 #include <errno.h>
30 #include <malloc.h>
31 
32 #ifdef USE_HOSTCC		/* HOST build */
33 # include <string.h>
34 # include <assert.h>
35 # include <ctype.h>
36 
37 # ifndef debug
38 #  ifdef DEBUG
39 #   define debug(fmt,args...)	printf(fmt ,##args)
40 #  else
41 #   define debug(fmt,args...)
42 #  endif
43 # endif
44 #else				/* U-Boot build */
45 # include <common.h>
46 # include <linux/string.h>
47 # include <linux/ctype.h>
48 #endif
49 
50 #ifndef	CONFIG_ENV_MIN_ENTRIES	/* minimum number of entries */
51 #define	CONFIG_ENV_MIN_ENTRIES 64
52 #endif
53 #ifndef	CONFIG_ENV_MAX_ENTRIES	/* maximum number of entries */
54 #define	CONFIG_ENV_MAX_ENTRIES 512
55 #endif
56 
57 #include "search.h"
58 
59 /*
60  * [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
61  * [Knuth]	      The Art of Computer Programming, part 3 (6.4)
62  */
63 
64 /*
65  * The reentrant version has no static variables to maintain the state.
66  * Instead the interface of all functions is extended to take an argument
67  * which describes the current status.
68  */
69 
70 typedef struct _ENTRY {
71 	int used;
72 	ENTRY entry;
73 } _ENTRY;
74 
75 
76 static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
77 	int idx);
78 
79 /*
80  * hcreate()
81  */
82 
83 /*
84  * For the used double hash method the table size has to be a prime. To
85  * correct the user given table size we need a prime test.  This trivial
86  * algorithm is adequate because
87  * a)  the code is (most probably) called a few times per program run and
88  * b)  the number is small because the table must fit in the core
89  * */
90 static int isprime(unsigned int number)
91 {
92 	/* no even number will be passed */
93 	unsigned int div = 3;
94 
95 	while (div * div < number && number % div != 0)
96 		div += 2;
97 
98 	return number % div != 0;
99 }
100 
101 /*
102  * Before using the hash table we must allocate memory for it.
103  * Test for an existing table are done. We allocate one element
104  * more as the found prime number says. This is done for more effective
105  * indexing as explained in the comment for the hsearch function.
106  * The contents of the table is zeroed, especially the field used
107  * becomes zero.
108  */
109 
110 int hcreate_r(size_t nel, struct hsearch_data *htab)
111 {
112 	/* Test for correct arguments.  */
113 	if (htab == NULL) {
114 		__set_errno(EINVAL);
115 		return 0;
116 	}
117 
118 	/* There is still another table active. Return with error. */
119 	if (htab->table != NULL)
120 		return 0;
121 
122 	/* Change nel to the first prime number not smaller as nel. */
123 	nel |= 1;		/* make odd */
124 	while (!isprime(nel))
125 		nel += 2;
126 
127 	htab->size = nel;
128 	htab->filled = 0;
129 
130 	/* allocate memory and zero out */
131 	htab->table = (_ENTRY *) calloc(htab->size + 1, sizeof(_ENTRY));
132 	if (htab->table == NULL)
133 		return 0;
134 
135 	/* everything went alright */
136 	return 1;
137 }
138 
139 
140 /*
141  * hdestroy()
142  */
143 
144 /*
145  * After using the hash table it has to be destroyed. The used memory can
146  * be freed and the local static variable can be marked as not used.
147  */
148 
149 void hdestroy_r(struct hsearch_data *htab)
150 {
151 	int i;
152 
153 	/* Test for correct arguments.  */
154 	if (htab == NULL) {
155 		__set_errno(EINVAL);
156 		return;
157 	}
158 
159 	/* free used memory */
160 	for (i = 1; i <= htab->size; ++i) {
161 		if (htab->table[i].used > 0) {
162 			ENTRY *ep = &htab->table[i].entry;
163 
164 			free((void *)ep->key);
165 			free(ep->data);
166 		}
167 	}
168 	free(htab->table);
169 
170 	/* the sign for an existing table is an value != NULL in htable */
171 	htab->table = NULL;
172 }
173 
174 /*
175  * hsearch()
176  */
177 
178 /*
179  * This is the search function. It uses double hashing with open addressing.
180  * The argument item.key has to be a pointer to an zero terminated, most
181  * probably strings of chars. The function for generating a number of the
182  * strings is simple but fast. It can be replaced by a more complex function
183  * like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
184  *
185  * We use an trick to speed up the lookup. The table is created by hcreate
186  * with one more element available. This enables us to use the index zero
187  * special. This index will never be used because we store the first hash
188  * index in the field used where zero means not used. Every other value
189  * means used. The used field can be used as a first fast comparison for
190  * equality of the stored and the parameter value. This helps to prevent
191  * unnecessary expensive calls of strcmp.
192  *
193  * This implementation differs from the standard library version of
194  * this function in a number of ways:
195  *
196  * - While the standard version does not make any assumptions about
197  *   the type of the stored data objects at all, this implementation
198  *   works with NUL terminated strings only.
199  * - Instead of storing just pointers to the original objects, we
200  *   create local copies so the caller does not need to care about the
201  *   data any more.
202  * - The standard implementation does not provide a way to update an
203  *   existing entry.  This version will create a new entry or update an
204  *   existing one when both "action == ENTER" and "item.data != NULL".
205  * - Instead of returning 1 on success, we return the index into the
206  *   internal hash table, which is also guaranteed to be positive.
207  *   This allows us direct access to the found hash table slot for
208  *   example for functions like hdelete().
209  */
210 
211 /*
212  * hstrstr_r - return index to entry whose key and/or data contains match
213  */
214 int hstrstr_r(const char *match, int last_idx, ENTRY ** retval,
215 	      struct hsearch_data *htab)
216 {
217 	unsigned int idx;
218 
219 	for (idx = last_idx + 1; idx < htab->size; ++idx) {
220 		if (htab->table[idx].used <= 0)
221 			continue;
222 		if (strstr(htab->table[idx].entry.key, match) ||
223 		    strstr(htab->table[idx].entry.data, match)) {
224 			*retval = &htab->table[idx].entry;
225 			return idx;
226 		}
227 	}
228 
229 	__set_errno(ESRCH);
230 	*retval = NULL;
231 	return 0;
232 }
233 
234 int hmatch_r(const char *match, int last_idx, ENTRY ** retval,
235 	     struct hsearch_data *htab)
236 {
237 	unsigned int idx;
238 	size_t key_len = strlen(match);
239 
240 	for (idx = last_idx + 1; idx < htab->size; ++idx) {
241 		if (htab->table[idx].used <= 0)
242 			continue;
243 		if (!strncmp(match, htab->table[idx].entry.key, key_len)) {
244 			*retval = &htab->table[idx].entry;
245 			return idx;
246 		}
247 	}
248 
249 	__set_errno(ESRCH);
250 	*retval = NULL;
251 	return 0;
252 }
253 
254 /*
255  * Compare an existing entry with the desired key, and overwrite if the action
256  * is ENTER.  This is simply a helper function for hsearch_r().
257  */
258 static inline int _compare_and_overwrite_entry(ENTRY item, ACTION action,
259 	ENTRY **retval, struct hsearch_data *htab, int flag,
260 	unsigned int hval, unsigned int idx)
261 {
262 	if (htab->table[idx].used == hval
263 	    && strcmp(item.key, htab->table[idx].entry.key) == 0) {
264 		/* Overwrite existing value? */
265 		if ((action == ENTER) && (item.data != NULL)) {
266 			/* check for permission */
267 			if (htab->change_ok != NULL && htab->change_ok(
268 			    &htab->table[idx].entry, item.data,
269 			    env_op_overwrite, flag)) {
270 				debug("change_ok() rejected setting variable "
271 					"%s, skipping it!\n", item.key);
272 				__set_errno(EPERM);
273 				*retval = NULL;
274 				return 0;
275 			}
276 
277 			free(htab->table[idx].entry.data);
278 			htab->table[idx].entry.data = strdup(item.data);
279 			if (!htab->table[idx].entry.data) {
280 				__set_errno(ENOMEM);
281 				*retval = NULL;
282 				return 0;
283 			}
284 		}
285 		/* return found entry */
286 		*retval = &htab->table[idx].entry;
287 		return idx;
288 	}
289 	/* keep searching */
290 	return -1;
291 }
292 
293 int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval,
294 	      struct hsearch_data *htab, int flag)
295 {
296 	unsigned int hval;
297 	unsigned int count;
298 	unsigned int len = strlen(item.key);
299 	unsigned int idx;
300 	unsigned int first_deleted = 0;
301 	int ret;
302 
303 	/* Compute an value for the given string. Perhaps use a better method. */
304 	hval = len;
305 	count = len;
306 	while (count-- > 0) {
307 		hval <<= 4;
308 		hval += item.key[count];
309 	}
310 
311 	/*
312 	 * First hash function:
313 	 * simply take the modul but prevent zero.
314 	 */
315 	hval %= htab->size;
316 	if (hval == 0)
317 		++hval;
318 
319 	/* The first index tried. */
320 	idx = hval;
321 
322 	if (htab->table[idx].used) {
323 		/*
324 		 * Further action might be required according to the
325 		 * action value.
326 		 */
327 		unsigned hval2;
328 
329 		if (htab->table[idx].used == -1
330 		    && !first_deleted)
331 			first_deleted = idx;
332 
333 		ret = _compare_and_overwrite_entry(item, action, retval, htab,
334 			flag, hval, idx);
335 		if (ret != -1)
336 			return ret;
337 
338 		/*
339 		 * Second hash function:
340 		 * as suggested in [Knuth]
341 		 */
342 		hval2 = 1 + hval % (htab->size - 2);
343 
344 		do {
345 			/*
346 			 * Because SIZE is prime this guarantees to
347 			 * step through all available indices.
348 			 */
349 			if (idx <= hval2)
350 				idx = htab->size + idx - hval2;
351 			else
352 				idx -= hval2;
353 
354 			/*
355 			 * If we visited all entries leave the loop
356 			 * unsuccessfully.
357 			 */
358 			if (idx == hval)
359 				break;
360 
361 			/* If entry is found use it. */
362 			ret = _compare_and_overwrite_entry(item, action, retval,
363 				htab, flag, hval, idx);
364 			if (ret != -1)
365 				return ret;
366 		}
367 		while (htab->table[idx].used);
368 	}
369 
370 	/* An empty bucket has been found. */
371 	if (action == ENTER) {
372 		/*
373 		 * If table is full and another entry should be
374 		 * entered return with error.
375 		 */
376 		if (htab->filled == htab->size) {
377 			__set_errno(ENOMEM);
378 			*retval = NULL;
379 			return 0;
380 		}
381 
382 		/*
383 		 * Create new entry;
384 		 * create copies of item.key and item.data
385 		 */
386 		if (first_deleted)
387 			idx = first_deleted;
388 
389 		htab->table[idx].used = hval;
390 		htab->table[idx].entry.key = strdup(item.key);
391 		htab->table[idx].entry.data = strdup(item.data);
392 		if (!htab->table[idx].entry.key ||
393 		    !htab->table[idx].entry.data) {
394 			__set_errno(ENOMEM);
395 			*retval = NULL;
396 			return 0;
397 		}
398 
399 		++htab->filled;
400 
401 		/* check for permission */
402 		if (htab->change_ok != NULL && htab->change_ok(
403 		    &htab->table[idx].entry, item.data, env_op_create, flag)) {
404 			debug("change_ok() rejected setting variable "
405 				"%s, skipping it!\n", item.key);
406 			_hdelete(item.key, htab, &htab->table[idx].entry, idx);
407 			__set_errno(EPERM);
408 			*retval = NULL;
409 			return 0;
410 		}
411 
412 		/* return new entry */
413 		*retval = &htab->table[idx].entry;
414 		return 1;
415 	}
416 
417 	__set_errno(ESRCH);
418 	*retval = NULL;
419 	return 0;
420 }
421 
422 
423 /*
424  * hdelete()
425  */
426 
427 /*
428  * The standard implementation of hsearch(3) does not provide any way
429  * to delete any entries from the hash table.  We extend the code to
430  * do that.
431  */
432 
433 static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
434 	int idx)
435 {
436 	/* free used ENTRY */
437 	debug("hdelete: DELETING key \"%s\"\n", key);
438 	free((void *)ep->key);
439 	free(ep->data);
440 	htab->table[idx].used = -1;
441 
442 	--htab->filled;
443 }
444 
445 int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
446 {
447 	ENTRY e, *ep;
448 	int idx;
449 
450 	debug("hdelete: DELETE key \"%s\"\n", key);
451 
452 	e.key = (char *)key;
453 
454 	idx = hsearch_r(e, FIND, &ep, htab, 0);
455 	if (idx == 0) {
456 		__set_errno(ESRCH);
457 		return 0;	/* not found */
458 	}
459 
460 	/* Check for permission */
461 	if (htab->change_ok != NULL &&
462 	    htab->change_ok(ep, NULL, env_op_delete, flag)) {
463 		debug("change_ok() rejected deleting variable "
464 			"%s, skipping it!\n", key);
465 		__set_errno(EPERM);
466 		return 0;
467 	}
468 
469 	_hdelete(key, htab, ep, idx);
470 
471 	return 1;
472 }
473 
474 /*
475  * hexport()
476  */
477 
478 #ifndef CONFIG_SPL_BUILD
479 /*
480  * Export the data stored in the hash table in linearized form.
481  *
482  * Entries are exported as "name=value" strings, separated by an
483  * arbitrary (non-NUL, of course) separator character. This allows to
484  * use this function both when formatting the U-Boot environment for
485  * external storage (using '\0' as separator), but also when using it
486  * for the "printenv" command to print all variables, simply by using
487  * as '\n" as separator. This can also be used for new features like
488  * exporting the environment data as text file, including the option
489  * for later re-import.
490  *
491  * The entries in the result list will be sorted by ascending key
492  * values.
493  *
494  * If the separator character is different from NUL, then any
495  * separator characters and backslash characters in the values will
496  * be escaped by a preceeding backslash in output. This is needed for
497  * example to enable multi-line values, especially when the output
498  * shall later be parsed (for example, for re-import).
499  *
500  * There are several options how the result buffer is handled:
501  *
502  * *resp  size
503  * -----------
504  *  NULL    0	A string of sufficient length will be allocated.
505  *  NULL   >0	A string of the size given will be
506  *		allocated. An error will be returned if the size is
507  *		not sufficient.  Any unused bytes in the string will
508  *		be '\0'-padded.
509  * !NULL    0	The user-supplied buffer will be used. No length
510  *		checking will be performed, i. e. it is assumed that
511  *		the buffer size will always be big enough. DANGEROUS.
512  * !NULL   >0	The user-supplied buffer will be used. An error will
513  *		be returned if the size is not sufficient.  Any unused
514  *		bytes in the string will be '\0'-padded.
515  */
516 
517 static int cmpkey(const void *p1, const void *p2)
518 {
519 	ENTRY *e1 = *(ENTRY **) p1;
520 	ENTRY *e2 = *(ENTRY **) p2;
521 
522 	return (strcmp(e1->key, e2->key));
523 }
524 
525 ssize_t hexport_r(struct hsearch_data *htab, const char sep,
526 		 char **resp, size_t size,
527 		 int argc, char * const argv[])
528 {
529 	ENTRY *list[htab->size];
530 	char *res, *p;
531 	size_t totlen;
532 	int i, n;
533 
534 	/* Test for correct arguments.  */
535 	if ((resp == NULL) || (htab == NULL)) {
536 		__set_errno(EINVAL);
537 		return (-1);
538 	}
539 
540 	debug("EXPORT  table = %p, htab.size = %d, htab.filled = %d, "
541 		"size = %zu\n", htab, htab->size, htab->filled, size);
542 	/*
543 	 * Pass 1:
544 	 * search used entries,
545 	 * save addresses and compute total length
546 	 */
547 	for (i = 1, n = 0, totlen = 0; i <= htab->size; ++i) {
548 
549 		if (htab->table[i].used > 0) {
550 			ENTRY *ep = &htab->table[i].entry;
551 			int arg, found = 0;
552 
553 			for (arg = 0; arg < argc; ++arg) {
554 				if (strcmp(argv[arg], ep->key) == 0) {
555 					found = 1;
556 					break;
557 				}
558 			}
559 			if ((argc > 0) && (found == 0))
560 				continue;
561 
562 			list[n++] = ep;
563 
564 			totlen += strlen(ep->key) + 2;
565 
566 			if (sep == '\0') {
567 				totlen += strlen(ep->data);
568 			} else {	/* check if escapes are needed */
569 				char *s = ep->data;
570 
571 				while (*s) {
572 					++totlen;
573 					/* add room for needed escape chars */
574 					if ((*s == sep) || (*s == '\\'))
575 						++totlen;
576 					++s;
577 				}
578 			}
579 			totlen += 2;	/* for '=' and 'sep' char */
580 		}
581 	}
582 
583 #ifdef DEBUG
584 	/* Pass 1a: print unsorted list */
585 	printf("Unsorted: n=%d\n", n);
586 	for (i = 0; i < n; ++i) {
587 		printf("\t%3d: %p ==> %-10s => %s\n",
588 		       i, list[i], list[i]->key, list[i]->data);
589 	}
590 #endif
591 
592 	/* Sort list by keys */
593 	qsort(list, n, sizeof(ENTRY *), cmpkey);
594 
595 	/* Check if the user supplied buffer size is sufficient */
596 	if (size) {
597 		if (size < totlen + 1) {	/* provided buffer too small */
598 			printf("Env export buffer too small: %zu, "
599 				"but need %zu\n", size, totlen + 1);
600 			__set_errno(ENOMEM);
601 			return (-1);
602 		}
603 	} else {
604 		size = totlen + 1;
605 	}
606 
607 	/* Check if the user provided a buffer */
608 	if (*resp) {
609 		/* yes; clear it */
610 		res = *resp;
611 		memset(res, '\0', size);
612 	} else {
613 		/* no, allocate and clear one */
614 		*resp = res = calloc(1, size);
615 		if (res == NULL) {
616 			__set_errno(ENOMEM);
617 			return (-1);
618 		}
619 	}
620 	/*
621 	 * Pass 2:
622 	 * export sorted list of result data
623 	 */
624 	for (i = 0, p = res; i < n; ++i) {
625 		const char *s;
626 
627 		s = list[i]->key;
628 		while (*s)
629 			*p++ = *s++;
630 		*p++ = '=';
631 
632 		s = list[i]->data;
633 
634 		while (*s) {
635 			if ((*s == sep) || (*s == '\\'))
636 				*p++ = '\\';	/* escape */
637 			*p++ = *s++;
638 		}
639 		*p++ = sep;
640 	}
641 	*p = '\0';		/* terminate result */
642 
643 	return size;
644 }
645 #endif
646 
647 
648 /*
649  * himport()
650  */
651 
652 /*
653  * Check whether variable 'name' is amongst vars[],
654  * and remove all instances by setting the pointer to NULL
655  */
656 static int drop_var_from_set(const char *name, int nvars, char * vars[])
657 {
658 	int i = 0;
659 	int res = 0;
660 
661 	/* No variables specified means process all of them */
662 	if (nvars == 0)
663 		return 1;
664 
665 	for (i = 0; i < nvars; i++) {
666 		if (vars[i] == NULL)
667 			continue;
668 		/* If we found it, delete all of them */
669 		if (!strcmp(name, vars[i])) {
670 			vars[i] = NULL;
671 			res = 1;
672 		}
673 	}
674 	if (!res)
675 		debug("Skipping non-listed variable %s\n", name);
676 
677 	return res;
678 }
679 
680 /*
681  * Import linearized data into hash table.
682  *
683  * This is the inverse function to hexport(): it takes a linear list
684  * of "name=value" pairs and creates hash table entries from it.
685  *
686  * Entries without "value", i. e. consisting of only "name" or
687  * "name=", will cause this entry to be deleted from the hash table.
688  *
689  * The "flag" argument can be used to control the behaviour: when the
690  * H_NOCLEAR bit is set, then an existing hash table will kept, i. e.
691  * new data will be added to an existing hash table; otherwise, old
692  * data will be discarded and a new hash table will be created.
693  *
694  * The separator character for the "name=value" pairs can be selected,
695  * so we both support importing from externally stored environment
696  * data (separated by NUL characters) and from plain text files
697  * (entries separated by newline characters).
698  *
699  * To allow for nicely formatted text input, leading white space
700  * (sequences of SPACE and TAB chars) is ignored, and entries starting
701  * (after removal of any leading white space) with a '#' character are
702  * considered comments and ignored.
703  *
704  * [NOTE: this means that a variable name cannot start with a '#'
705  * character.]
706  *
707  * When using a non-NUL separator character, backslash is used as
708  * escape character in the value part, allowing for example for
709  * multi-line values.
710  *
711  * In theory, arbitrary separator characters can be used, but only
712  * '\0' and '\n' have really been tested.
713  */
714 
715 int himport_r(struct hsearch_data *htab,
716 		const char *env, size_t size, const char sep, int flag,
717 		int nvars, char * const vars[])
718 {
719 	char *data, *sp, *dp, *name, *value;
720 	char *localvars[nvars];
721 	int i;
722 
723 	/* Test for correct arguments.  */
724 	if (htab == NULL) {
725 		__set_errno(EINVAL);
726 		return 0;
727 	}
728 
729 	/* we allocate new space to make sure we can write to the array */
730 	if ((data = malloc(size)) == NULL) {
731 		debug("himport_r: can't malloc %zu bytes\n", size);
732 		__set_errno(ENOMEM);
733 		return 0;
734 	}
735 	memcpy(data, env, size);
736 	dp = data;
737 
738 	/* make a local copy of the list of variables */
739 	if (nvars)
740 		memcpy(localvars, vars, sizeof(vars[0]) * nvars);
741 
742 	if ((flag & H_NOCLEAR) == 0) {
743 		/* Destroy old hash table if one exists */
744 		debug("Destroy Hash Table: %p table = %p\n", htab,
745 		       htab->table);
746 		if (htab->table)
747 			hdestroy_r(htab);
748 	}
749 
750 	/*
751 	 * Create new hash table (if needed).  The computation of the hash
752 	 * table size is based on heuristics: in a sample of some 70+
753 	 * existing systems we found an average size of 39+ bytes per entry
754 	 * in the environment (for the whole key=value pair). Assuming a
755 	 * size of 8 per entry (= safety factor of ~5) should provide enough
756 	 * safety margin for any existing environment definitions and still
757 	 * allow for more than enough dynamic additions. Note that the
758 	 * "size" argument is supposed to give the maximum enviroment size
759 	 * (CONFIG_ENV_SIZE).  This heuristics will result in
760 	 * unreasonably large numbers (and thus memory footprint) for
761 	 * big flash environments (>8,000 entries for 64 KB
762 	 * envrionment size), so we clip it to a reasonable value.
763 	 * On the other hand we need to add some more entries for free
764 	 * space when importing very small buffers. Both boundaries can
765 	 * be overwritten in the board config file if needed.
766 	 */
767 
768 	if (!htab->table) {
769 		int nent = CONFIG_ENV_MIN_ENTRIES + size / 8;
770 
771 		if (nent > CONFIG_ENV_MAX_ENTRIES)
772 			nent = CONFIG_ENV_MAX_ENTRIES;
773 
774 		debug("Create Hash Table: N=%d\n", nent);
775 
776 		if (hcreate_r(nent, htab) == 0) {
777 			free(data);
778 			return 0;
779 		}
780 	}
781 
782 	/* Parse environment; allow for '\0' and 'sep' as separators */
783 	do {
784 		ENTRY e, *rv;
785 
786 		/* skip leading white space */
787 		while (isblank(*dp))
788 			++dp;
789 
790 		/* skip comment lines */
791 		if (*dp == '#') {
792 			while (*dp && (*dp != sep))
793 				++dp;
794 			++dp;
795 			continue;
796 		}
797 
798 		/* parse name */
799 		for (name = dp; *dp != '=' && *dp && *dp != sep; ++dp)
800 			;
801 
802 		/* deal with "name" and "name=" entries (delete var) */
803 		if (*dp == '\0' || *(dp + 1) == '\0' ||
804 		    *dp == sep || *(dp + 1) == sep) {
805 			if (*dp == '=')
806 				*dp++ = '\0';
807 			*dp++ = '\0';	/* terminate name */
808 
809 			debug("DELETE CANDIDATE: \"%s\"\n", name);
810 			if (!drop_var_from_set(name, nvars, localvars))
811 				continue;
812 
813 			if (hdelete_r(name, htab, flag) == 0)
814 				debug("DELETE ERROR ##############################\n");
815 
816 			continue;
817 		}
818 		*dp++ = '\0';	/* terminate name */
819 
820 		/* parse value; deal with escapes */
821 		for (value = sp = dp; *dp && (*dp != sep); ++dp) {
822 			if ((*dp == '\\') && *(dp + 1))
823 				++dp;
824 			*sp++ = *dp;
825 		}
826 		*sp++ = '\0';	/* terminate value */
827 		++dp;
828 
829 		/* Skip variables which are not supposed to be processed */
830 		if (!drop_var_from_set(name, nvars, localvars))
831 			continue;
832 
833 		/* enter into hash table */
834 		e.key = name;
835 		e.data = value;
836 
837 		hsearch_r(e, ENTER, &rv, htab, flag);
838 		if (rv == NULL) {
839 			printf("himport_r: can't insert \"%s=%s\" into hash table\n",
840 				name, value);
841 			return 0;
842 		}
843 
844 		debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"\n",
845 			htab, htab->filled, htab->size,
846 			rv, name, value);
847 	} while ((dp < data + size) && *dp);	/* size check needed for text */
848 						/* without '\0' termination */
849 	debug("INSERT: free(data = %p)\n", data);
850 	free(data);
851 
852 	/* process variables which were not considered */
853 	for (i = 0; i < nvars; i++) {
854 		if (localvars[i] == NULL)
855 			continue;
856 		/*
857 		 * All variables which were not deleted from the variable list
858 		 * were not present in the imported env
859 		 * This could mean two things:
860 		 * a) if the variable was present in current env, we delete it
861 		 * b) if the variable was not present in current env, we notify
862 		 *    it might be a typo
863 		 */
864 		if (hdelete_r(localvars[i], htab, flag) == 0)
865 			printf("WARNING: '%s' neither in running nor in imported env!\n", localvars[i]);
866 		else
867 			printf("WARNING: '%s' not in imported env, deleting it!\n", localvars[i]);
868 	}
869 
870 	debug("INSERT: done\n");
871 	return 1;		/* everything OK */
872 }
873