2 * This implementation is based on code from uClibc-0.9.30.3 but was
3 * modified and extended for use within U-Boot.
5 * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
7 * Original license header:
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.
13 * SPDX-License-Identifier: LGPL-2.1+
19 #ifdef USE_HOSTCC /* HOST build */
26 # define debug(fmt,args...) printf(fmt ,##args)
28 # define debug(fmt,args...)
31 #else /* U-Boot build */
33 # include <linux/string.h>
34 # include <linux/ctype.h>
37 #ifndef CONFIG_ENV_MIN_ENTRIES /* minimum number of entries */
38 #define CONFIG_ENV_MIN_ENTRIES 64
40 #ifndef CONFIG_ENV_MAX_ENTRIES /* maximum number of entries */
41 #define CONFIG_ENV_MAX_ENTRIES 512
44 #include <env_callback.h>
45 #include <env_flags.h>
50 * [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
51 * [Knuth] The Art of Computer Programming, part 3 (6.4)
55 * The reentrant version has no static variables to maintain the state.
56 * Instead the interface of all functions is extended to take an argument
57 * which describes the current status.
60 typedef struct _ENTRY {
66 static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
74 * For the used double hash method the table size has to be a prime. To
75 * correct the user given table size we need a prime test. This trivial
76 * algorithm is adequate because
77 * a) the code is (most probably) called a few times per program run and
78 * b) the number is small because the table must fit in the core
80 static int isprime(unsigned int number)
82 /* no even number will be passed */
85 while (div * div < number && number % div != 0)
88 return number % div != 0;
92 * Before using the hash table we must allocate memory for it.
93 * Test for an existing table are done. We allocate one element
94 * more as the found prime number says. This is done for more effective
95 * indexing as explained in the comment for the hsearch function.
96 * The contents of the table is zeroed, especially the field used
100 int hcreate_r(size_t nel, struct hsearch_data *htab)
102 /* Test for correct arguments. */
108 /* There is still another table active. Return with error. */
109 if (htab->table != NULL)
112 /* Change nel to the first prime number not smaller as nel. */
113 nel |= 1; /* make odd */
114 while (!isprime(nel))
120 /* allocate memory and zero out */
121 htab->table = (_ENTRY *) calloc(htab->size + 1, sizeof(_ENTRY));
122 if (htab->table == NULL)
125 /* everything went alright */
135 * After using the hash table it has to be destroyed. The used memory can
136 * be freed and the local static variable can be marked as not used.
139 void hdestroy_r(struct hsearch_data *htab)
143 /* Test for correct arguments. */
149 /* free used memory */
150 for (i = 1; i <= htab->size; ++i) {
151 if (htab->table[i].used > 0) {
152 ENTRY *ep = &htab->table[i].entry;
154 free((void *)ep->key);
160 /* the sign for an existing table is an value != NULL in htable */
169 * This is the search function. It uses double hashing with open addressing.
170 * The argument item.key has to be a pointer to an zero terminated, most
171 * probably strings of chars. The function for generating a number of the
172 * strings is simple but fast. It can be replaced by a more complex function
173 * like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
175 * We use an trick to speed up the lookup. The table is created by hcreate
176 * with one more element available. This enables us to use the index zero
177 * special. This index will never be used because we store the first hash
178 * index in the field used where zero means not used. Every other value
179 * means used. The used field can be used as a first fast comparison for
180 * equality of the stored and the parameter value. This helps to prevent
181 * unnecessary expensive calls of strcmp.
183 * This implementation differs from the standard library version of
184 * this function in a number of ways:
186 * - While the standard version does not make any assumptions about
187 * the type of the stored data objects at all, this implementation
188 * works with NUL terminated strings only.
189 * - Instead of storing just pointers to the original objects, we
190 * create local copies so the caller does not need to care about the
192 * - The standard implementation does not provide a way to update an
193 * existing entry. This version will create a new entry or update an
194 * existing one when both "action == ENTER" and "item.data != NULL".
195 * - Instead of returning 1 on success, we return the index into the
196 * internal hash table, which is also guaranteed to be positive.
197 * This allows us direct access to the found hash table slot for
198 * example for functions like hdelete().
201 int hmatch_r(const char *match, int last_idx, ENTRY ** retval,
202 struct hsearch_data *htab)
205 size_t key_len = strlen(match);
207 for (idx = last_idx + 1; idx < htab->size; ++idx) {
208 if (htab->table[idx].used <= 0)
210 if (!strncmp(match, htab->table[idx].entry.key, key_len)) {
211 *retval = &htab->table[idx].entry;
222 * Compare an existing entry with the desired key, and overwrite if the action
223 * is ENTER. This is simply a helper function for hsearch_r().
225 static inline int _compare_and_overwrite_entry(ENTRY item, ACTION action,
226 ENTRY **retval, struct hsearch_data *htab, int flag,
227 unsigned int hval, unsigned int idx)
229 if (htab->table[idx].used == hval
230 && strcmp(item.key, htab->table[idx].entry.key) == 0) {
231 /* Overwrite existing value? */
232 if ((action == ENTER) && (item.data != NULL)) {
233 /* check for permission */
234 if (htab->change_ok != NULL && htab->change_ok(
235 &htab->table[idx].entry, item.data,
236 env_op_overwrite, flag)) {
237 debug("change_ok() rejected setting variable "
238 "%s, skipping it!\n", item.key);
244 /* If there is a callback, call it */
245 if (htab->table[idx].entry.callback &&
246 htab->table[idx].entry.callback(item.key,
247 item.data, env_op_overwrite, flag)) {
248 debug("callback() rejected setting variable "
249 "%s, skipping it!\n", item.key);
255 free(htab->table[idx].entry.data);
256 htab->table[idx].entry.data = strdup(item.data);
257 if (!htab->table[idx].entry.data) {
263 /* return found entry */
264 *retval = &htab->table[idx].entry;
271 int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval,
272 struct hsearch_data *htab, int flag)
276 unsigned int len = strlen(item.key);
278 unsigned int first_deleted = 0;
281 /* Compute an value for the given string. Perhaps use a better method. */
284 while (count-- > 0) {
286 hval += item.key[count];
290 * First hash function:
291 * simply take the modul but prevent zero.
297 /* The first index tried. */
300 if (htab->table[idx].used) {
302 * Further action might be required according to the
307 if (htab->table[idx].used == -1
311 ret = _compare_and_overwrite_entry(item, action, retval, htab,
317 * Second hash function:
318 * as suggested in [Knuth]
320 hval2 = 1 + hval % (htab->size - 2);
324 * Because SIZE is prime this guarantees to
325 * step through all available indices.
328 idx = htab->size + idx - hval2;
333 * If we visited all entries leave the loop
339 /* If entry is found use it. */
340 ret = _compare_and_overwrite_entry(item, action, retval,
341 htab, flag, hval, idx);
345 while (htab->table[idx].used);
348 /* An empty bucket has been found. */
349 if (action == ENTER) {
351 * If table is full and another entry should be
352 * entered return with error.
354 if (htab->filled == htab->size) {
362 * create copies of item.key and item.data
367 htab->table[idx].used = hval;
368 htab->table[idx].entry.key = strdup(item.key);
369 htab->table[idx].entry.data = strdup(item.data);
370 if (!htab->table[idx].entry.key ||
371 !htab->table[idx].entry.data) {
379 /* This is a new entry, so look up a possible callback */
380 env_callback_init(&htab->table[idx].entry);
381 /* Also look for flags */
382 env_flags_init(&htab->table[idx].entry);
384 /* check for permission */
385 if (htab->change_ok != NULL && htab->change_ok(
386 &htab->table[idx].entry, item.data, env_op_create, flag)) {
387 debug("change_ok() rejected setting variable "
388 "%s, skipping it!\n", item.key);
389 _hdelete(item.key, htab, &htab->table[idx].entry, idx);
395 /* If there is a callback, call it */
396 if (htab->table[idx].entry.callback &&
397 htab->table[idx].entry.callback(item.key, item.data,
398 env_op_create, flag)) {
399 debug("callback() rejected setting variable "
400 "%s, skipping it!\n", item.key);
401 _hdelete(item.key, htab, &htab->table[idx].entry, idx);
407 /* return new entry */
408 *retval = &htab->table[idx].entry;
423 * The standard implementation of hsearch(3) does not provide any way
424 * to delete any entries from the hash table. We extend the code to
428 static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
431 /* free used ENTRY */
432 debug("hdelete: DELETING key \"%s\"\n", key);
433 free((void *)ep->key);
437 htab->table[idx].used = -1;
442 int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
447 debug("hdelete: DELETE key \"%s\"\n", key);
451 idx = hsearch_r(e, FIND, &ep, htab, 0);
454 return 0; /* not found */
457 /* Check for permission */
458 if (htab->change_ok != NULL &&
459 htab->change_ok(ep, NULL, env_op_delete, flag)) {
460 debug("change_ok() rejected deleting variable "
461 "%s, skipping it!\n", key);
466 /* If there is a callback, call it */
467 if (htab->table[idx].entry.callback &&
468 htab->table[idx].entry.callback(key, NULL, env_op_delete, flag)) {
469 debug("callback() rejected deleting variable "
470 "%s, skipping it!\n", key);
475 _hdelete(key, htab, ep, idx);
484 #ifndef CONFIG_SPL_BUILD
486 * Export the data stored in the hash table in linearized form.
488 * Entries are exported as "name=value" strings, separated by an
489 * arbitrary (non-NUL, of course) separator character. This allows to
490 * use this function both when formatting the U-Boot environment for
491 * external storage (using '\0' as separator), but also when using it
492 * for the "printenv" command to print all variables, simply by using
493 * as '\n" as separator. This can also be used for new features like
494 * exporting the environment data as text file, including the option
495 * for later re-import.
497 * The entries in the result list will be sorted by ascending key
500 * If the separator character is different from NUL, then any
501 * separator characters and backslash characters in the values will
502 * be escaped by a preceeding backslash in output. This is needed for
503 * example to enable multi-line values, especially when the output
504 * shall later be parsed (for example, for re-import).
506 * There are several options how the result buffer is handled:
510 * NULL 0 A string of sufficient length will be allocated.
511 * NULL >0 A string of the size given will be
512 * allocated. An error will be returned if the size is
513 * not sufficient. Any unused bytes in the string will
515 * !NULL 0 The user-supplied buffer will be used. No length
516 * checking will be performed, i. e. it is assumed that
517 * the buffer size will always be big enough. DANGEROUS.
518 * !NULL >0 The user-supplied buffer will be used. An error will
519 * be returned if the size is not sufficient. Any unused
520 * bytes in the string will be '\0'-padded.
523 static int cmpkey(const void *p1, const void *p2)
525 ENTRY *e1 = *(ENTRY **) p1;
526 ENTRY *e2 = *(ENTRY **) p2;
528 return (strcmp(e1->key, e2->key));
531 static int match_string(int flag, const char *str, const char *pat, void *priv)
533 switch (flag & H_MATCH_METHOD) {
535 if (strcmp(str, pat) == 0)
539 if (strstr(str, pat))
545 struct slre *slrep = (struct slre *)priv;
546 struct cap caps[slrep->num_caps + 2];
548 if (slre_match(slrep, str, strlen(str), caps))
554 printf("## ERROR: unsupported match method: 0x%02x\n",
555 flag & H_MATCH_METHOD);
561 static int match_entry(ENTRY *ep, int flag,
562 int argc, char * const argv[])
567 for (arg = 0; arg < argc; ++arg) {
571 if (slre_compile(&slre, argv[arg]) == 0) {
572 printf("Error compiling regex: %s\n", slre.err_str);
576 priv = (void *)&slre;
578 if (flag & H_MATCH_KEY) {
579 if (match_string(flag, ep->key, argv[arg], priv))
582 if (flag & H_MATCH_DATA) {
583 if (match_string(flag, ep->data, argv[arg], priv))
590 ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
591 char **resp, size_t size,
592 int argc, char * const argv[])
594 ENTRY *list[htab->size];
599 /* Test for correct arguments. */
600 if ((resp == NULL) || (htab == NULL)) {
605 debug("EXPORT table = %p, htab.size = %d, htab.filled = %d, "
606 "size = %zu\n", htab, htab->size, htab->filled, size);
609 * search used entries,
610 * save addresses and compute total length
612 for (i = 1, n = 0, totlen = 0; i <= htab->size; ++i) {
614 if (htab->table[i].used > 0) {
615 ENTRY *ep = &htab->table[i].entry;
616 int found = match_entry(ep, flag, argc, argv);
618 if ((argc > 0) && (found == 0))
621 if ((flag & H_HIDE_DOT) && ep->key[0] == '.')
626 totlen += strlen(ep->key) + 2;
629 totlen += strlen(ep->data);
630 } else { /* check if escapes are needed */
635 /* add room for needed escape chars */
636 if ((*s == sep) || (*s == '\\'))
641 totlen += 2; /* for '=' and 'sep' char */
646 /* Pass 1a: print unsorted list */
647 printf("Unsorted: n=%d\n", n);
648 for (i = 0; i < n; ++i) {
649 printf("\t%3d: %p ==> %-10s => %s\n",
650 i, list[i], list[i]->key, list[i]->data);
654 /* Sort list by keys */
655 qsort(list, n, sizeof(ENTRY *), cmpkey);
657 /* Check if the user supplied buffer size is sufficient */
659 if (size < totlen + 1) { /* provided buffer too small */
660 printf("Env export buffer too small: %zu, "
661 "but need %zu\n", size, totlen + 1);
669 /* Check if the user provided a buffer */
673 memset(res, '\0', size);
675 /* no, allocate and clear one */
676 *resp = res = calloc(1, size);
684 * export sorted list of result data
686 for (i = 0, p = res; i < n; ++i) {
697 if ((*s == sep) || (*s == '\\'))
698 *p++ = '\\'; /* escape */
703 *p = '\0'; /* terminate result */
715 * Check whether variable 'name' is amongst vars[],
716 * and remove all instances by setting the pointer to NULL
718 static int drop_var_from_set(const char *name, int nvars, char * vars[])
723 /* No variables specified means process all of them */
727 for (i = 0; i < nvars; i++) {
730 /* If we found it, delete all of them */
731 if (!strcmp(name, vars[i])) {
737 debug("Skipping non-listed variable %s\n", name);
743 * Import linearized data into hash table.
745 * This is the inverse function to hexport(): it takes a linear list
746 * of "name=value" pairs and creates hash table entries from it.
748 * Entries without "value", i. e. consisting of only "name" or
749 * "name=", will cause this entry to be deleted from the hash table.
751 * The "flag" argument can be used to control the behaviour: when the
752 * H_NOCLEAR bit is set, then an existing hash table will kept, i. e.
753 * new data will be added to an existing hash table; otherwise, old
754 * data will be discarded and a new hash table will be created.
756 * The separator character for the "name=value" pairs can be selected,
757 * so we both support importing from externally stored environment
758 * data (separated by NUL characters) and from plain text files
759 * (entries separated by newline characters).
761 * To allow for nicely formatted text input, leading white space
762 * (sequences of SPACE and TAB chars) is ignored, and entries starting
763 * (after removal of any leading white space) with a '#' character are
764 * considered comments and ignored.
766 * [NOTE: this means that a variable name cannot start with a '#'
769 * When using a non-NUL separator character, backslash is used as
770 * escape character in the value part, allowing for example for
773 * In theory, arbitrary separator characters can be used, but only
774 * '\0' and '\n' have really been tested.
777 int himport_r(struct hsearch_data *htab,
778 const char *env, size_t size, const char sep, int flag,
779 int crlf_is_lf, int nvars, char * const vars[])
781 char *data, *sp, *dp, *name, *value;
782 char *localvars[nvars];
785 /* Test for correct arguments. */
791 /* we allocate new space to make sure we can write to the array */
792 if ((data = malloc(size + 1)) == NULL) {
793 debug("himport_r: can't malloc %zu bytes\n", size + 1);
797 memcpy(data, env, size);
801 /* make a local copy of the list of variables */
803 memcpy(localvars, vars, sizeof(vars[0]) * nvars);
805 if ((flag & H_NOCLEAR) == 0) {
806 /* Destroy old hash table if one exists */
807 debug("Destroy Hash Table: %p table = %p\n", htab,
814 * Create new hash table (if needed). The computation of the hash
815 * table size is based on heuristics: in a sample of some 70+
816 * existing systems we found an average size of 39+ bytes per entry
817 * in the environment (for the whole key=value pair). Assuming a
818 * size of 8 per entry (= safety factor of ~5) should provide enough
819 * safety margin for any existing environment definitions and still
820 * allow for more than enough dynamic additions. Note that the
821 * "size" argument is supposed to give the maximum environment size
822 * (CONFIG_ENV_SIZE). This heuristics will result in
823 * unreasonably large numbers (and thus memory footprint) for
824 * big flash environments (>8,000 entries for 64 KB
825 * envrionment size), so we clip it to a reasonable value.
826 * On the other hand we need to add some more entries for free
827 * space when importing very small buffers. Both boundaries can
828 * be overwritten in the board config file if needed.
832 int nent = CONFIG_ENV_MIN_ENTRIES + size / 8;
834 if (nent > CONFIG_ENV_MAX_ENTRIES)
835 nent = CONFIG_ENV_MAX_ENTRIES;
837 debug("Create Hash Table: N=%d\n", nent);
839 if (hcreate_r(nent, htab) == 0) {
846 return 1; /* everything OK */
848 /* Remove Carriage Returns in front of Line Feeds */
849 unsigned ignored_crs = 0;
850 for(;dp < data + size && *dp; ++dp) {
852 dp < data + size - 1 && *(dp+1) == '\n')
855 *(dp-ignored_crs) = *dp;
860 /* Parse environment; allow for '\0' and 'sep' as separators */
864 /* skip leading white space */
868 /* skip comment lines */
870 while (*dp && (*dp != sep))
877 for (name = dp; *dp != '=' && *dp && *dp != sep; ++dp)
880 /* deal with "name" and "name=" entries (delete var) */
881 if (*dp == '\0' || *(dp + 1) == '\0' ||
882 *dp == sep || *(dp + 1) == sep) {
885 *dp++ = '\0'; /* terminate name */
887 debug("DELETE CANDIDATE: \"%s\"\n", name);
888 if (!drop_var_from_set(name, nvars, localvars))
891 if (hdelete_r(name, htab, flag) == 0)
892 debug("DELETE ERROR ##############################\n");
896 *dp++ = '\0'; /* terminate name */
898 /* parse value; deal with escapes */
899 for (value = sp = dp; *dp && (*dp != sep); ++dp) {
900 if ((*dp == '\\') && *(dp + 1))
904 *sp++ = '\0'; /* terminate value */
908 debug("INSERT: unable to use an empty key\n");
913 /* Skip variables which are not supposed to be processed */
914 if (!drop_var_from_set(name, nvars, localvars))
917 /* enter into hash table */
921 hsearch_r(e, ENTER, &rv, htab, flag);
923 printf("himport_r: can't insert \"%s=%s\" into hash table\n",
926 debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"\n",
927 htab, htab->filled, htab->size,
929 } while ((dp < data + size) && *dp); /* size check needed for text */
930 /* without '\0' termination */
931 debug("INSERT: free(data = %p)\n", data);
934 /* process variables which were not considered */
935 for (i = 0; i < nvars; i++) {
936 if (localvars[i] == NULL)
939 * All variables which were not deleted from the variable list
940 * were not present in the imported env
941 * This could mean two things:
942 * a) if the variable was present in current env, we delete it
943 * b) if the variable was not present in current env, we notify
946 if (hdelete_r(localvars[i], htab, flag) == 0)
947 printf("WARNING: '%s' neither in running nor in imported env!\n", localvars[i]);
949 printf("WARNING: '%s' not in imported env, deleting it!\n", localvars[i]);
952 debug("INSERT: done\n");
953 return 1; /* everything OK */
961 * Walk all of the entries in the hash, calling the callback for each one.
962 * this allows some generic operation to be performed on each element.
964 int hwalk_r(struct hsearch_data *htab, int (*callback)(ENTRY *))
969 for (i = 1; i <= htab->size; ++i) {
970 if (htab->table[i].used > 0) {
971 retval = callback(&htab->table[i].entry);