1 // SPDX-License-Identifier: LGPL-2.1+
2 /*
3 * This implementation is based on code from uClibc-0.9.30.3 but was
4 * modified and extended for use within U-Boot.
5 *
6 * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
7 *
8 * Original license header:
9 *
10 * Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
11 * This file is part of the GNU C Library.
12 * Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1993.
13 */
14
15 #include <errno.h>
16 #include <log.h>
17 #include <malloc.h>
18 #include <sort.h>
19
20 #ifdef USE_HOSTCC /* HOST build */
21 # include <string.h>
22 # include <assert.h>
23 # include <ctype.h>
24
25 # ifndef debug
26 # ifdef DEBUG
27 # define debug(fmt,args...) printf(fmt ,##args)
28 # else
29 # define debug(fmt,args...)
30 # endif
31 # endif
32 #else /* U-Boot build */
33 # include <linux/string.h>
34 # include <linux/ctype.h>
35 #endif
36
37 #define USED_FREE 0
38 #define USED_DELETED -1
39
40 #include <env_callback.h>
41 #include <env_flags.h>
42 #include <search.h>
43 #include <slre.h>
44
45 /*
46 * [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
47 * [Knuth] The Art of Computer Programming, part 3 (6.4)
48 */
49
50 /*
51 * The reentrant version has no static variables to maintain the state.
52 * Instead the interface of all functions is extended to take an argument
53 * which describes the current status.
54 */
55
56 struct env_entry_node {
57 int used;
58 struct env_entry entry;
59 };
60
61 static void _hdelete(const char *key, struct hsearch_data *htab,
62 struct env_entry *ep, int idx);
63
64 /*
65 * hcreate()
66 */
67
68 /*
69 * For the used double hash method the table size has to be a prime. To
70 * correct the user given table size we need a prime test. This trivial
71 * algorithm is adequate because
72 * a) the code is (most probably) called a few times per program run and
73 * b) the number is small because the table must fit in the core
74 * */
isprime(unsigned int number)75 static int isprime(unsigned int number)
76 {
77 /* no even number will be passed */
78 unsigned int div = 3;
79
80 while (div * div < number && number % div != 0)
81 div += 2;
82
83 return number % div != 0;
84 }
85
86 /*
87 * Before using the hash table we must allocate memory for it.
88 * Test for an existing table are done. We allocate one element
89 * more as the found prime number says. This is done for more effective
90 * indexing as explained in the comment for the hsearch function.
91 * The contents of the table is zeroed, especially the field used
92 * becomes zero.
93 */
94
hcreate_r(size_t nel,struct hsearch_data * htab)95 int hcreate_r(size_t nel, struct hsearch_data *htab)
96 {
97 /* Test for correct arguments. */
98 if (htab == NULL) {
99 __set_errno(EINVAL);
100 return 0;
101 }
102
103 /* There is still another table active. Return with error. */
104 if (htab->table != NULL) {
105 __set_errno(EINVAL);
106 return 0;
107 }
108
109 /* Change nel to the first prime number not smaller as nel. */
110 nel |= 1; /* make odd */
111 while (!isprime(nel))
112 nel += 2;
113
114 htab->size = nel;
115 htab->filled = 0;
116
117 /* allocate memory and zero out */
118 htab->table = (struct env_entry_node *)calloc(htab->size + 1,
119 sizeof(struct env_entry_node));
120 if (htab->table == NULL) {
121 __set_errno(ENOMEM);
122 return 0;
123 }
124
125 /* everything went alright */
126 return 1;
127 }
128
129 /*
130 * hdestroy()
131 */
132
133 /*
134 * After using the hash table it has to be destroyed. The used memory can
135 * be freed and the local static variable can be marked as not used.
136 */
137
hdestroy_r(struct hsearch_data * htab)138 void hdestroy_r(struct hsearch_data *htab)
139 {
140 int i;
141
142 /* Test for correct arguments. */
143 if (htab == NULL) {
144 __set_errno(EINVAL);
145 return;
146 }
147
148 /* free used memory */
149 for (i = 1; i <= htab->size; ++i) {
150 if (htab->table[i].used > 0) {
151 struct env_entry *ep = &htab->table[i].entry;
152
153 free((void *)ep->key);
154 free(ep->data);
155 }
156 }
157 free(htab->table);
158
159 /* the sign for an existing table is an value != NULL in htable */
160 htab->table = NULL;
161 }
162
163 /*
164 * hsearch()
165 */
166
167 /*
168 * This is the search function. It uses double hashing with open addressing.
169 * The argument item.key has to be a pointer to an zero terminated, most
170 * probably strings of chars. The function for generating a number of the
171 * strings is simple but fast. It can be replaced by a more complex function
172 * like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
173 *
174 * We use an trick to speed up the lookup. The table is created by hcreate
175 * with one more element available. This enables us to use the index zero
176 * special. This index will never be used because we store the first hash
177 * index in the field used where zero means not used. Every other value
178 * means used. The used field can be used as a first fast comparison for
179 * equality of the stored and the parameter value. This helps to prevent
180 * unnecessary expensive calls of strcmp.
181 *
182 * This implementation differs from the standard library version of
183 * this function in a number of ways:
184 *
185 * - While the standard version does not make any assumptions about
186 * the type of the stored data objects at all, this implementation
187 * works with NUL terminated strings only.
188 * - Instead of storing just pointers to the original objects, we
189 * create local copies so the caller does not need to care about the
190 * data any more.
191 * - The standard implementation does not provide a way to update an
192 * existing entry. This version will create a new entry or update an
193 * existing one when both "action == ENV_ENTER" and "item.data != NULL".
194 * - Instead of returning 1 on success, we return the index into the
195 * internal hash table, which is also guaranteed to be positive.
196 * This allows us direct access to the found hash table slot for
197 * example for functions like hdelete().
198 */
199
hmatch_r(const char * match,int last_idx,struct env_entry ** retval,struct hsearch_data * htab)200 int hmatch_r(const char *match, int last_idx, struct env_entry **retval,
201 struct hsearch_data *htab)
202 {
203 unsigned int idx;
204 size_t key_len = strlen(match);
205
206 for (idx = last_idx + 1; idx < htab->size; ++idx) {
207 if (htab->table[idx].used <= 0)
208 continue;
209 if (!strncmp(match, htab->table[idx].entry.key, key_len)) {
210 *retval = &htab->table[idx].entry;
211 return idx;
212 }
213 }
214
215 __set_errno(ESRCH);
216 *retval = NULL;
217 return 0;
218 }
219
220 static int
do_callback(const struct env_entry * e,const char * name,const char * value,enum env_op op,int flags)221 do_callback(const struct env_entry *e, const char *name, const char *value,
222 enum env_op op, int flags)
223 {
224 int ret = 0;
225
226 #ifndef CONFIG_XPL_BUILD
227 static bool in_callback;
228
229 if (!e->callback || in_callback)
230 return 0;
231
232 /*
233 * In case there are two variables which each implement env callback
234 * that performs env_set() on the other variable, the callbacks will
235 * call each other recursively until the stack runs out. Prevent such
236 * a recursion from happening.
237 *
238 * Example which triggers this behavior:
239 * static int on_foo(...) { env_set("bar", 0); ... }
240 * static int on_bar(...) { env_set("foo", 0); ... }
241 * U_BOOT_ENV_CALLBACK(foo, on_foo);
242 * U_BOOT_ENV_CALLBACK(bar, on_bar);
243 */
244 in_callback = true;
245 ret = e->callback(name, value, op, flags);
246 in_callback = false;
247 #endif
248
249 return ret;
250 }
251
252 /*
253 * Compare an existing entry with the desired key, and overwrite if the action
254 * is ENV_ENTER. This is simply a helper function for hsearch_r().
255 */
_compare_and_overwrite_entry(struct env_entry item,enum env_action action,struct env_entry ** retval,struct hsearch_data * htab,int flag,unsigned int hval,unsigned int idx)256 static inline int _compare_and_overwrite_entry(struct env_entry item,
257 enum env_action action, struct env_entry **retval,
258 struct hsearch_data *htab, int flag, unsigned int hval,
259 unsigned int idx)
260 {
261 if (htab->table[idx].used == hval
262 && strcmp(item.key, htab->table[idx].entry.key) == 0) {
263 /* Overwrite existing value? */
264 if (action == ENV_ENTER && item.data) {
265 /* check for permission */
266 if (htab->change_ok != NULL && htab->change_ok(
267 &htab->table[idx].entry, item.data,
268 env_op_overwrite, flag)) {
269 debug("change_ok() rejected setting variable "
270 "%s, skipping it!\n", item.key);
271 __set_errno(EPERM);
272 *retval = NULL;
273 return 0;
274 }
275
276 /* If there is a callback, call it */
277 if (do_callback(&htab->table[idx].entry, item.key,
278 item.data, env_op_overwrite, flag)) {
279 debug("callback() rejected setting variable "
280 "%s, skipping it!\n", item.key);
281 __set_errno(EINVAL);
282 *retval = NULL;
283 return 0;
284 }
285
286 free(htab->table[idx].entry.data);
287 htab->table[idx].entry.data = strdup(item.data);
288 if (!htab->table[idx].entry.data) {
289 __set_errno(ENOMEM);
290 *retval = NULL;
291 return 0;
292 }
293 }
294 /* return found entry */
295 *retval = &htab->table[idx].entry;
296 return idx;
297 }
298 /* keep searching */
299 return -1;
300 }
301
hsearch_r(struct env_entry item,enum env_action action,struct env_entry ** retval,struct hsearch_data * htab,int flag)302 int hsearch_r(struct env_entry item, enum env_action action,
303 struct env_entry **retval, struct hsearch_data *htab, int flag)
304 {
305 unsigned int hval;
306 unsigned int count;
307 unsigned int len = strlen(item.key);
308 unsigned int idx;
309 unsigned int first_deleted = 0;
310 int ret;
311
312 /* Compute an value for the given string. Perhaps use a better method. */
313 hval = len;
314 count = len;
315 while (count-- > 0) {
316 hval <<= 4;
317 hval += item.key[count];
318 }
319
320 /*
321 * First hash function:
322 * simply take the modul but prevent zero.
323 */
324 hval %= htab->size;
325 if (hval == 0)
326 ++hval;
327
328 /* The first index tried. */
329 idx = hval;
330
331 if (htab->table[idx].used) {
332 /*
333 * Further action might be required according to the
334 * action value.
335 */
336 unsigned hval2;
337
338 if (htab->table[idx].used == USED_DELETED)
339 first_deleted = idx;
340
341 ret = _compare_and_overwrite_entry(item, action, retval, htab,
342 flag, hval, idx);
343 if (ret != -1)
344 return ret;
345
346 /*
347 * Second hash function:
348 * as suggested in [Knuth]
349 */
350 hval2 = 1 + hval % (htab->size - 2);
351
352 do {
353 /*
354 * Because SIZE is prime this guarantees to
355 * step through all available indices.
356 */
357 if (idx <= hval2)
358 idx = htab->size + idx - hval2;
359 else
360 idx -= hval2;
361
362 /*
363 * If we visited all entries leave the loop
364 * unsuccessfully.
365 */
366 if (idx == hval)
367 break;
368
369 if (htab->table[idx].used == USED_DELETED
370 && !first_deleted)
371 first_deleted = idx;
372
373 /* If entry is found use it. */
374 ret = _compare_and_overwrite_entry(item, action, retval,
375 htab, flag, hval, idx);
376 if (ret != -1)
377 return ret;
378 }
379 while (htab->table[idx].used != USED_FREE);
380 }
381
382 /* An empty bucket has been found. */
383 if (action == ENV_ENTER) {
384 /*
385 * If table is full and another entry should be
386 * entered return with error.
387 */
388 if (htab->filled == htab->size) {
389 __set_errno(ENOMEM);
390 *retval = NULL;
391 return 0;
392 }
393
394 /*
395 * Create new entry;
396 * create copies of item.key and item.data
397 */
398 if (first_deleted)
399 idx = first_deleted;
400
401 htab->table[idx].used = hval;
402 htab->table[idx].entry.key = strdup(item.key);
403 htab->table[idx].entry.data = strdup(item.data);
404 if (!htab->table[idx].entry.key ||
405 !htab->table[idx].entry.data) {
406 __set_errno(ENOMEM);
407 *retval = NULL;
408 return 0;
409 }
410
411 ++htab->filled;
412
413 /* This is a new entry, so look up a possible callback */
414 env_callback_init(&htab->table[idx].entry);
415 /* Also look for flags */
416 env_flags_init(&htab->table[idx].entry);
417
418 /* check for permission */
419 if (htab->change_ok != NULL && htab->change_ok(
420 &htab->table[idx].entry, item.data, env_op_create, flag)) {
421 debug("change_ok() rejected setting variable "
422 "%s, skipping it!\n", item.key);
423 _hdelete(item.key, htab, &htab->table[idx].entry, idx);
424 __set_errno(EPERM);
425 *retval = NULL;
426 return 0;
427 }
428
429 /* If there is a callback, call it */
430 if (do_callback(&htab->table[idx].entry, item.key, item.data,
431 env_op_create, flag)) {
432 debug("callback() rejected setting variable "
433 "%s, skipping it!\n", item.key);
434 _hdelete(item.key, htab, &htab->table[idx].entry, idx);
435 __set_errno(EINVAL);
436 *retval = NULL;
437 return 0;
438 }
439
440 /* return new entry */
441 *retval = &htab->table[idx].entry;
442 return 1;
443 }
444
445 __set_errno(ESRCH);
446 *retval = NULL;
447 return 0;
448 }
449
450 /*
451 * hdelete()
452 */
453
454 /*
455 * The standard implementation of hsearch(3) does not provide any way
456 * to delete any entries from the hash table. We extend the code to
457 * do that.
458 */
459
_hdelete(const char * key,struct hsearch_data * htab,struct env_entry * ep,int idx)460 static void _hdelete(const char *key, struct hsearch_data *htab,
461 struct env_entry *ep, int idx)
462 {
463 /* free used entry */
464 debug("hdelete: DELETING key \"%s\"\n", key);
465 free((void *)ep->key);
466 free(ep->data);
467 ep->flags = 0;
468 htab->table[idx].used = USED_DELETED;
469
470 --htab->filled;
471 }
472
hdelete_r(const char * key,struct hsearch_data * htab,int flag)473 int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
474 {
475 struct env_entry e, *ep;
476 int idx;
477
478 debug("hdelete: DELETE key \"%s\"\n", key);
479
480 e.key = (char *)key;
481
482 idx = hsearch_r(e, ENV_FIND, &ep, htab, 0);
483 if (idx == 0) {
484 __set_errno(ESRCH);
485 return -ENOENT; /* not found */
486 }
487
488 /* Check for permission */
489 if (htab->change_ok != NULL &&
490 htab->change_ok(ep, NULL, env_op_delete, flag)) {
491 debug("change_ok() rejected deleting variable "
492 "%s, skipping it!\n", key);
493 __set_errno(EPERM);
494 return -EPERM;
495 }
496
497 /* If there is a callback, call it */
498 if (do_callback(&htab->table[idx].entry, key, NULL,
499 env_op_delete, flag)) {
500 debug("callback() rejected deleting variable "
501 "%s, skipping it!\n", key);
502 __set_errno(EINVAL);
503 return -EINVAL;
504 }
505
506 _hdelete(key, htab, ep, idx);
507
508 return 0;
509 }
510
511 #if !(defined(CONFIG_XPL_BUILD) && !defined(CONFIG_SPL_SAVEENV))
512 /*
513 * hexport()
514 */
515
516 /*
517 * Export the data stored in the hash table in linearized form.
518 *
519 * Entries are exported as "name=value" strings, separated by an
520 * arbitrary (non-NUL, of course) separator character. This allows to
521 * use this function both when formatting the U-Boot environment for
522 * external storage (using '\0' as separator), but also when using it
523 * for the "printenv" command to print all variables, simply by using
524 * as '\n" as separator. This can also be used for new features like
525 * exporting the environment data as text file, including the option
526 * for later re-import.
527 *
528 * The entries in the result list will be sorted by ascending key
529 * values.
530 *
531 * If the separator character is different from NUL, then any
532 * separator characters and backslash characters in the values will
533 * be escaped by a preceding backslash in output. This is needed for
534 * example to enable multi-line values, especially when the output
535 * shall later be parsed (for example, for re-import).
536 *
537 * There are several options how the result buffer is handled:
538 *
539 * *resp size
540 * -----------
541 * NULL 0 A string of sufficient length will be allocated.
542 * NULL >0 A string of the size given will be
543 * allocated. An error will be returned if the size is
544 * not sufficient. Any unused bytes in the string will
545 * be '\0'-padded.
546 * !NULL 0 The user-supplied buffer will be used. No length
547 * checking will be performed, i. e. it is assumed that
548 * the buffer size will always be big enough. DANGEROUS.
549 * !NULL >0 The user-supplied buffer will be used. An error will
550 * be returned if the size is not sufficient. Any unused
551 * bytes in the string will be '\0'-padded.
552 */
553
cmpkey(const void * p1,const void * p2)554 static int cmpkey(const void *p1, const void *p2)
555 {
556 struct env_entry *e1 = *(struct env_entry **)p1;
557 struct env_entry *e2 = *(struct env_entry **)p2;
558
559 return (strcmp(e1->key, e2->key));
560 }
561
match_string(int flag,const char * str,const char * pat,void * priv)562 static int match_string(int flag, const char *str, const char *pat, void *priv)
563 {
564 switch (flag & H_MATCH_METHOD) {
565 case H_MATCH_IDENT:
566 if (strcmp(str, pat) == 0)
567 return 1;
568 break;
569 case H_MATCH_SUBSTR:
570 if (strstr(str, pat))
571 return 1;
572 break;
573 #ifdef CONFIG_REGEX
574 case H_MATCH_REGEX:
575 {
576 struct slre *slrep = (struct slre *)priv;
577
578 if (slre_match(slrep, str, strlen(str), NULL))
579 return 1;
580 }
581 break;
582 #endif
583 default:
584 printf("## ERROR: unsupported match method: 0x%02x\n",
585 flag & H_MATCH_METHOD);
586 break;
587 }
588 return 0;
589 }
590
match_entry(struct env_entry * ep,int flag,int argc,char * const argv[])591 static int match_entry(struct env_entry *ep, int flag, int argc,
592 char *const argv[])
593 {
594 int arg;
595 void *priv = NULL;
596
597 for (arg = 0; arg < argc; ++arg) {
598 #ifdef CONFIG_REGEX
599 struct slre slre;
600
601 if (slre_compile(&slre, argv[arg]) == 0) {
602 printf("Error compiling regex: %s\n", slre.err_str);
603 return 0;
604 }
605
606 priv = (void *)&slre;
607 #endif
608 if (flag & H_MATCH_KEY) {
609 if (match_string(flag, ep->key, argv[arg], priv))
610 return 1;
611 }
612 if (flag & H_MATCH_DATA) {
613 if (match_string(flag, ep->data, argv[arg], priv))
614 return 1;
615 }
616 }
617 return 0;
618 }
619
hexport_r(struct hsearch_data * htab,const char sep,int flag,char ** resp,size_t size,int argc,char * const argv[])620 ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
621 char **resp, size_t size,
622 int argc, char *const argv[])
623 {
624 struct env_entry *list[htab->size];
625 char *res, *p;
626 size_t totlen;
627 int i, n;
628
629 /* Test for correct arguments. */
630 if ((resp == NULL) || (htab == NULL)) {
631 __set_errno(EINVAL);
632 return (-1);
633 }
634
635 debug("EXPORT table = %p, htab.size = %d, htab.filled = %d, size = %lu\n",
636 htab, htab->size, htab->filled, (ulong)size);
637 /*
638 * Pass 1:
639 * search used entries,
640 * save addresses and compute total length
641 */
642 for (i = 1, n = 0, totlen = 0; i <= htab->size; ++i) {
643
644 if (htab->table[i].used > 0) {
645 struct env_entry *ep = &htab->table[i].entry;
646 int found = match_entry(ep, flag, argc, argv);
647
648 if ((argc > 0) && (found == 0))
649 continue;
650
651 if ((flag & H_HIDE_DOT) && ep->key[0] == '.')
652 continue;
653
654 list[n++] = ep;
655
656 totlen += strlen(ep->key);
657
658 if (sep == '\0') {
659 totlen += strlen(ep->data);
660 } else { /* check if escapes are needed */
661 char *s = ep->data;
662
663 while (*s) {
664 ++totlen;
665 /* add room for needed escape chars */
666 if ((*s == sep) || (*s == '\\'))
667 ++totlen;
668 ++s;
669 }
670 }
671 totlen += 2; /* for '=' and 'sep' char */
672 }
673 }
674
675 #ifdef DEBUG
676 /* Pass 1a: print unsorted list */
677 printf("Unsorted: n=%d\n", n);
678 for (i = 0; i < n; ++i) {
679 printf("\t%3d: %p ==> %-10s => %s\n",
680 i, list[i], list[i]->key, list[i]->data);
681 }
682 #endif
683
684 /* Sort list by keys */
685 qsort(list, n, sizeof(struct env_entry *), cmpkey);
686
687 /* Check if the user supplied buffer size is sufficient */
688 if (size) {
689 if (size < totlen + 1) { /* provided buffer too small */
690 printf("Env export buffer too small: %lu, but need %lu\n",
691 (ulong)size, (ulong)totlen + 1);
692 __set_errno(ENOMEM);
693 return (-1);
694 }
695 } else {
696 size = totlen + 1;
697 }
698
699 /* Check if the user provided a buffer */
700 if (*resp) {
701 /* yes; clear it */
702 res = *resp;
703 memset(res, '\0', size);
704 } else {
705 /* no, allocate and clear one */
706 *resp = res = calloc(1, size);
707 if (res == NULL) {
708 __set_errno(ENOMEM);
709 return (-1);
710 }
711 }
712 /*
713 * Pass 2:
714 * export sorted list of result data
715 */
716 for (i = 0, p = res; i < n; ++i) {
717 const char *s;
718
719 s = list[i]->key;
720 while (*s)
721 *p++ = *s++;
722 *p++ = '=';
723
724 s = list[i]->data;
725
726 while (*s) {
727 if ((*s == sep) || (*s == '\\'))
728 *p++ = '\\'; /* escape */
729 *p++ = *s++;
730 }
731 *p++ = sep;
732 }
733 *p = '\0'; /* terminate result */
734
735 return size;
736 }
737 #endif
738
739 /*
740 * himport()
741 */
742
743 /*
744 * Check whether variable 'name' is amongst vars[],
745 * and remove all instances by setting the pointer to NULL
746 */
drop_var_from_set(const char * name,int nvars,char * vars[])747 static int drop_var_from_set(const char *name, int nvars, char * vars[])
748 {
749 int i = 0;
750 int res = 0;
751
752 /* No variables specified means process all of them */
753 if (nvars == 0)
754 return 1;
755
756 for (i = 0; i < nvars; i++) {
757 if (vars[i] == NULL)
758 continue;
759 /* If we found it, delete all of them */
760 if (!strcmp(name, vars[i])) {
761 vars[i] = NULL;
762 res = 1;
763 }
764 }
765 if (!res)
766 debug("Skipping non-listed variable %s\n", name);
767
768 return res;
769 }
770
771 /*
772 * Import linearized data into hash table.
773 *
774 * This is the inverse function to hexport(): it takes a linear list
775 * of "name=value" pairs and creates hash table entries from it.
776 *
777 * Entries without "value", i. e. consisting of only "name" or
778 * "name=", will cause this entry to be deleted from the hash table.
779 *
780 * The "flag" argument can be used to control the behaviour: when the
781 * H_NOCLEAR bit is set, then an existing hash table will kept, i. e.
782 * new data will be added to an existing hash table; otherwise, if no
783 * vars are passed, old data will be discarded and a new hash table
784 * will be created. If vars are passed, passed vars that are not in
785 * the linear list of "name=value" pairs will be removed from the
786 * current hash table.
787 *
788 * The separator character for the "name=value" pairs can be selected,
789 * so we both support importing from externally stored environment
790 * data (separated by NUL characters) and from plain text files
791 * (entries separated by newline characters).
792 *
793 * To allow for nicely formatted text input, leading white space
794 * (sequences of SPACE and TAB chars) is ignored, and entries starting
795 * (after removal of any leading white space) with a '#' character are
796 * considered comments and ignored.
797 *
798 * [NOTE: this means that a variable name cannot start with a '#'
799 * character.]
800 *
801 * When using a non-NUL separator character, backslash is used as
802 * escape character in the value part, allowing for example for
803 * multi-line values.
804 *
805 * In theory, arbitrary separator characters can be used, but only
806 * '\0' and '\n' have really been tested.
807 */
808
himport_r(struct hsearch_data * htab,const char * env,size_t size,const char sep,int flag,int crlf_is_lf,int nvars,char * const vars[])809 int himport_r(struct hsearch_data *htab,
810 const char *env, size_t size, const char sep, int flag,
811 int crlf_is_lf, int nvars, char * const vars[])
812 {
813 char *data, *sp, *dp, *name, *value;
814 char *localvars[nvars];
815 int i;
816
817 /* Test for correct arguments. */
818 if (htab == NULL) {
819 __set_errno(EINVAL);
820 return 0;
821 }
822
823 /* we allocate new space to make sure we can write to the array */
824 if ((data = malloc(size + 1)) == NULL) {
825 debug("himport_r: can't malloc %lu bytes\n", (ulong)size + 1);
826 __set_errno(ENOMEM);
827 return 0;
828 }
829 memcpy(data, env, size);
830 data[size] = '\0';
831 dp = data;
832
833 /* make a local copy of the list of variables */
834 if (nvars)
835 memcpy(localvars, vars, sizeof(vars[0]) * nvars);
836
837 #if CONFIG_IS_ENABLED(ENV_APPEND)
838 flag |= H_NOCLEAR;
839 #endif
840
841 if ((flag & H_NOCLEAR) == 0 && !nvars) {
842 /* Destroy old hash table if one exists */
843 debug("Destroy Hash Table: %p table = %p\n", htab,
844 htab->table);
845 if (htab->table)
846 hdestroy_r(htab);
847 }
848
849 /*
850 * Create new hash table (if needed). The computation of the hash
851 * table size is based on heuristics: in a sample of some 70+
852 * existing systems we found an average size of 39+ bytes per entry
853 * in the environment (for the whole key=value pair). Assuming a
854 * size of 8 per entry (= safety factor of ~5) should provide enough
855 * safety margin for any existing environment definitions and still
856 * allow for more than enough dynamic additions. Note that the
857 * "size" argument is supposed to give the maximum environment size
858 * (CONFIG_ENV_SIZE). This heuristics will result in
859 * unreasonably large numbers (and thus memory footprint) for
860 * big flash environments (>8,000 entries for 64 KB
861 * environment size), so we clip it to a reasonable value.
862 * On the other hand we need to add some more entries for free
863 * space when importing very small buffers. Both boundaries can
864 * be overwritten in the board config file if needed.
865 */
866
867 if (!htab->table) {
868 int nent = CONFIG_ENV_MIN_ENTRIES + size / 8;
869
870 if (nent > CONFIG_ENV_MAX_ENTRIES)
871 nent = CONFIG_ENV_MAX_ENTRIES;
872
873 debug("Create Hash Table: N=%d\n", nent);
874
875 if (hcreate_r(nent, htab) == 0) {
876 free(data);
877 return 0;
878 }
879 }
880
881 if (!size) {
882 free(data);
883 return 1; /* everything OK */
884 }
885 if(crlf_is_lf) {
886 /* Remove Carriage Returns in front of Line Feeds */
887 unsigned ignored_crs = 0;
888 for(;dp < data + size && *dp; ++dp) {
889 if(*dp == '\r' &&
890 dp < data + size - 1 && *(dp+1) == '\n')
891 ++ignored_crs;
892 else
893 *(dp-ignored_crs) = *dp;
894 }
895 size -= ignored_crs;
896 dp = data;
897 }
898 /* Parse environment; allow for '\0' and 'sep' as separators */
899 do {
900 struct env_entry e, *rv;
901
902 /* skip leading white space */
903 while (isblank(*dp))
904 ++dp;
905
906 /* skip comment lines */
907 if (*dp == '#') {
908 while (*dp && (*dp != sep))
909 ++dp;
910 ++dp;
911 continue;
912 }
913
914 /* parse name */
915 for (name = dp; *dp != '=' && *dp && *dp != sep; ++dp)
916 ;
917
918 /* deal with "name" and "name=" entries (delete var) */
919 if (*dp == '\0' || *(dp + 1) == '\0' ||
920 *dp == sep || *(dp + 1) == sep) {
921 if (*dp == '=')
922 *dp++ = '\0';
923 *dp++ = '\0'; /* terminate name */
924
925 debug("DELETE CANDIDATE: \"%s\"\n", name);
926 if (!drop_var_from_set(name, nvars, localvars))
927 continue;
928
929 if (hdelete_r(name, htab, flag))
930 debug("DELETE ERROR ##############################\n");
931
932 continue;
933 }
934 *dp++ = '\0'; /* terminate name */
935
936 /* parse value; deal with escapes */
937 for (value = sp = dp; *dp && (*dp != sep); ++dp) {
938 if ((*dp == '\\') && *(dp + 1))
939 ++dp;
940 *sp++ = *dp;
941 }
942 *sp++ = '\0'; /* terminate value */
943 ++dp;
944
945 if (*name == 0) {
946 debug("INSERT: unable to use an empty key\n");
947 __set_errno(EINVAL);
948 free(data);
949 return 0;
950 }
951
952 /* Skip variables which are not supposed to be processed */
953 if (!drop_var_from_set(name, nvars, localvars))
954 continue;
955
956 /* enter into hash table */
957 e.key = name;
958 e.data = value;
959
960 hsearch_r(e, ENV_ENTER, &rv, htab, flag);
961 #if !IS_ENABLED(CONFIG_ENV_WRITEABLE_LIST)
962 if (rv == NULL) {
963 printf("himport_r: can't insert \"%s=%s\" into hash table\n",
964 name, value);
965 }
966 #endif
967
968 debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"\n",
969 htab, htab->filled, htab->size,
970 rv, name, value);
971 } while ((dp < data + size) && *dp); /* size check needed for text */
972 /* without '\0' termination */
973 debug("INSERT: free(data = %p)\n", data);
974 free(data);
975
976 if (flag & H_NOCLEAR)
977 goto end;
978
979 /* process variables which were not considered */
980 for (i = 0; i < nvars; i++) {
981 if (localvars[i] == NULL)
982 continue;
983 /*
984 * All variables which were not deleted from the variable list
985 * were not present in the imported env
986 * This could mean two things:
987 * a) if the variable was present in current env, we delete it
988 * b) if the variable was not present in current env, we notify
989 * it might be a typo
990 */
991 if (hdelete_r(localvars[i], htab, flag))
992 printf("WARNING: '%s' neither in running nor in imported env!\n", localvars[i]);
993 else
994 printf("WARNING: '%s' not in imported env, deleting it!\n", localvars[i]);
995 }
996
997 end:
998 debug("INSERT: done\n");
999 return 1; /* everything OK */
1000 }
1001
1002 /*
1003 * hwalk_r()
1004 */
1005
1006 /*
1007 * Walk all of the entries in the hash, calling the callback for each one.
1008 * this allows some generic operation to be performed on each element.
1009 */
hwalk_r(struct hsearch_data * htab,int (* callback)(struct env_entry * entry))1010 int hwalk_r(struct hsearch_data *htab, int (*callback)(struct env_entry *entry))
1011 {
1012 int i;
1013 int retval;
1014
1015 for (i = 1; i <= htab->size; ++i) {
1016 if (htab->table[i].used > 0) {
1017 retval = callback(&htab->table[i].entry);
1018 if (retval)
1019 return retval;
1020 }
1021 }
1022
1023 return 0;
1024 }
1025